57,705 results on '"Apollo - University of Cambridge Repository"'
Search Results
2. Chemically Assisted Precompression of Hydrogen Molecules in Alkaline-Earth Tetrahydrides
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Peña-Alvarez, Miriam, Binns, Jack, Marqués, Miriam, Kuzovnikov, Mikhail A, Dalladay-Simpson, Philip, Pickard, Chris J, Ackland, Graeme J, Gregoryanz, Eugene, Howie, Ross T, Peña-Alvarez, Miriam [0000-0001-7056-7158], Binns, Jack [0000-0001-5421-6841], Pickard, Chris J [0000-0002-9684-5432], Apollo - University of Cambridge Repository, and Apollo-University Of Cambridge Repository
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ddc:530 ,General Materials Science ,Physical and Theoretical Chemistry - Abstract
The journal of physical chemistry letters 13(36), 8447 - 8454 (2022). doi:10.1021/acs.jpclett.2c02157, Through a series of high pressure diamond anvil experiments, we report the synthesis of alkaline earth (Ca, Sr, Ba) tetrahydrides, and investigate their properties through Raman spectroscopy, X-ray diffraction, and density functional theory calculations. The tetrahydrides incorporate both atomic and quasi-molecular hydrogen, and we find that the frequency of the intramolecular stretching mode of the $H^{𝛿−}_2$ units downshifts from Ca to Sr and to Ba upon compression. The experimental results indicate that the larger the host cation, the longer the $H^{𝛿−}_2$ bond. Analysis of the electron localization function (ELF) demonstrates that the lengthening of the H–H bond is caused by the charge transfer from the metal to $H^{𝛿−}_2$ and by the steric effect of the metal host on the $H–H$ bond. This effect is most prominent for BaH$_4$, where the precompression of $H^{𝛿−}_2$ units at 50 GPa results in bond lengths comparable to that of pure $H_2$ above 275 GPa., Published by ACS, Washington, DC
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- 2022
3. Collective Mid-Infrared Vibrations in Surface-Enhanced Raman Scattering
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Mueller, Niclas S, Arul, Rakesh, Jakob, Lukas A, Blunt, Matthew Oliver, Földes, Tamás, Rosta, Edina, Baumberg, Jeremy J, Mueller, Niclas S [0000-0002-8688-1974], Arul, Rakesh [0000-0001-8355-2158], Blunt, Matthew Oliver [0000-0001-9877-4183], Rosta, Edina [0000-0002-9823-4766], Baumberg, Jeremy J [0000-0002-9606-9488], Apollo - University of Cambridge Repository, and Apollo-University Of Cambridge Repository
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vibrational exciton ,SERS ,Mechanical Engineering ,mid-infrared ,General Materials Science ,Bioengineering ,General Chemistry ,Spectrum Analysis, Raman ,Condensed Matter Physics ,collective vibration ,Vibration ,plasmonics - Abstract
Funder: Winton Programme for the Physics of Sustainability, Funder: Cambridge Commonwealth, European and International Trust, Funder: Trinity College, University of Cambridge, Funder: Deutsche Akademie der Naturforscher Leopoldina - Nationale Akademie der Wissenschaften, Funder: Rutherford Foundation of the Royal Society Te Aparangi of New Zealand, Surface-enhanced Raman scattering (SERS) is typically assumed to occur at individual molecules neglecting intermolecular vibrational coupling. Here, we show instead how collective vibrations from infrared (IR) coupled dipoles are seen in SERS from molecular monolayers. Mixing IR-active molecules with IR-inactive spacer molecules controls the intermolecular separation. Intermolecular coupling leads to vibrational frequency upshifts up to 8 cm-1, tuning with the mixing fraction and IR dipole strength, in excellent agreement with microscopic models and density functional theory. These cooperative frequency shifts can be used as a ruler to measure intermolecular distance and disorder with angstrom resolution. We demonstrate this for photochemical reactions of 4-nitrothiophenol, which depletes the number of neighboring IR-active molecules and breaks the collective vibration, enabling direct tracking of the reaction. Collective molecular vibrations reshape SERS spectra and need to be considered in the analysis of vibrational spectra throughout analytical chemistry and sensing.
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- 2022
4. Seroepidemiological Reconstruction of Long-term Chikungunya Virus Circulation in Burkina Faso and Gabon
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Lim, Jacqueline Kyungah, Ridde, Valery, Agnandji, Selidji Todagbe, Lell, Bertrand, Yaro, Seydou, Yang, Jae Seung, Hoinard, Damien, Weaver, Scott C, Vanhomwegen, Jessica, Salje, Henrik, Yoon, In-Kyu, Salje, Henrik [0000-0003-3626-4254], Apollo - University of Cambridge Repository, Apollo-University Of Cambridge Repository, International Vaccine Institute (IVI), School of Public Health [Montréal, Canada], Université de Montréal (UdeM), Centre de Recherches Médicales de Lambaréné, University of Tübingen, Medizinische Universität Wien = Medical University of Vienna, Centre Muraz [Bobo-Dioulasso, Burkina Faso], Institut Pasteur [Paris] (IP), University of Texas Medical Branch at Galveston, University of Cambridge [UK] (CAM), Coalition for Epidemic Preparedness Innovations [Washington, DC, États-Unis] (CEPI), H. S. was supported by the European Research Council (grant number 804744). I.-K. Y. and J. K. L. were supported by the Bill & Melinda Gates Foundation (grant number 1053432). S. C. W. was supported by the National Institutes of Health (grant number R24 AI120942).Potential conflicts of interest. H. S. reports being a paid consultant to Gavi, the Vaccine Alliance, for work understanding the potential of chikungunya vaccines. All other authors report no potential conflicts. Funding to pay the Open Access publication charges for this article was provided by the University of Cambridge., and European Project: 804744,H2020-EU.1.1.,ARBODYNAMIC(2019)
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Adult ,chikungunya ,Adolescent ,[SDV]Life Sciences [q-bio] ,virus diseases ,Infant ,Middle Aged ,Disease Outbreaks ,Young Adult ,Infectious Diseases ,Child, Preschool ,[SDV.MP.VIR]Life Sciences [q-bio]/Microbiology and Parasitology/Virology ,Africa ,Burkina Faso ,Humans ,Chikungunya Fever ,Immunology and Allergy ,[SDV.SPEE]Life Sciences [q-bio]/Santé publique et épidémiologie ,Gabon ,seroepidemiology ,Child ,Chikungunya virus - Abstract
Chikungunya virus (CHIKV) is a major public health concern worldwide. However, infection levels are rarely known, especially in Africa. We recruited individuals from Ouagadougou, Burkina Faso and Lambaréné, Gabon (age range, 1–55 years), tested their blood for CHIKV antibodies, and used serocatalytic models to reconstruct epidemiological histories. In Ouagadougou, 291 of 999 (29.1%) individuals were seropositive, ranging from 2% among those aged
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- 2022
5. On the order of Dehn twists
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Keating, Ailsa, Randal-Williams, Oscar, Keating, Ailsa [0000-0002-1288-3117], Randal-Williams, Oscar [0000-0002-7479-2878], Apollo - University of Cambridge Repository, and Apollo-University Of Cambridge Repository
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Mathematics - Geometric Topology ,Mathematics::Group Theory ,math.SG ,Mathematics - Symplectic Geometry ,FOS: Mathematics ,Symplectic Geometry (math.SG) ,math.GT ,Geometric Topology (math.GT) ,Mathematics::Geometric Topology - Abstract
This note records the order of a higher dimensional Dehn twist in a range of topologically significant groups., 7 pages. v2: Accepted version, to appear in NYJM
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- 2023
6. Anarchists for the State: From Egalitarian Opacity to Anticipating Thoughts of the Powerful
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Stasch, Rupert, Stasch, Rupert [0000-0002-4617-2153], Apollo - University of Cambridge Repository, and Apollo-University Of Cambridge Repository
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Archeology ,060101 anthropology ,Arts and Humanities (miscellaneous) ,Anthropology ,05 social sciences ,0507 social and economic geography ,0601 history and archaeology ,06 humanities and the arts ,16. Peace & justice ,050701 cultural studies - Abstract
Korowai of Indonesian Papua have shifted their political order from rejecting relations of authority, to actively subordinating themselves to government patrons and implementing state structures locally. This shift was caused by how internal complexities of the past Korowai egalitarian system have interacted with dramatic macrostructural changes in the intruding state. Previously, I linked Korowai ideas about opacity of minds to political egalitarianism. Analyzing the new political shifts here, I emphasize again how opacity doctrines are embedded in wider processes of exchange and kinship that involve attributing thoughts to others, trying to influence those thoughts, and trying to deal in egalitarian ways with unequal economic conditions, as well as with the intrinsically power-laden dynamics of intersubjectivity itself. The Korowai example suggests wider lessons in how state formation takes hold at extreme colonial and market peripheries, and how doctrines of the knowability of minds articulate with practical institutionalization of state administrative hierarchy.
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- 2021
7. Complex pattern of facial remapping in somatosensory cortex following congenital but not acquired hand loss
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Root, Victoria, Muret, Dollyane, Arribas, Maite, Amoruso, Elena, Thornton, John, Tarall-Jozwiak, Aurelie, Tracey, Irene, Makin, Tamar R, Apollo-University Of Cambridge Repository, University Of Cambridge, Root, Victoria [0000-0002-0500-3206], Muret, Dollyane [0000-0002-2626-654X], Makin, Tamar R [0000-0002-5816-8979], and Apollo - University of Cambridge Repository
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General Immunology and Microbiology ,General Neuroscience ,fMRI ,Motor Cortex ,Somatosensory Cortex ,General Medicine ,Hand ,Magnetic Resonance Imaging ,General Biochemistry, Genetics and Molecular Biology ,neuroscience ,cortical remapping ,phantom limb pain ,primary somatosensory cortex ,Phantom Limb ,Humans ,face somatotopoy ,human ,Research Article - Abstract
Peer reviewed: True, Cortical remapping after hand loss in the primary somatosensory cortex (S1) is thought to be predominantly dictated by cortical proximity, with adjacent body parts remapping into the deprived area. Traditionally, this remapping has been characterised by changes in the lip representation, which is assumed to be the immediate neighbour of the hand based on electrophysiological research in non-human primates. However, the orientation of facial somatotopy in humans is debated, with contrasting work reporting both an inverted and upright topography. We aimed to fill this gap in the S1 homunculus by investigating the topographic organisation of the face. Using both univariate and multivariate approaches we examined the extent of face-to-hand remapping in individuals with a congenital and acquired missing hand (hereafter one-handers and amputees, respectively), relative to two-handed controls. Participants were asked to move different facial parts (forehead, nose, lips, tongue) during functional MRI (fMRI) scanning. We first confirmed an upright face organisation in all three groups, with the upper-face and not the lips bordering the hand area. We further found little evidence for remapping of both forehead and lips in amputees, with no significant relationship to the chronicity of their phantom limb pain (PLP). In contrast, we found converging evidence for a complex pattern of face remapping in congenital one-handers across multiple facial parts, where relative to controls, the location of the cortical neighbour - the forehead - is shown to shift away from the deprived hand area, which is subsequently more activated by the lips and the tongue. Together, our findings demonstrate that the face representation in humans is highly plastic, but that this plasticity is restricted by the developmental stage of input deprivation, rather than cortical proximity.
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- 2022
8. Early asymmetric growth of planetary stagnant lids
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Callum Watson, Jerome A. Neufeld, Chloé Michaut, Apollo-University Of Cambridge Repository, University Of Cambridge, Watson, Callum [0000-0001-8807-6736], Neufeld, Jerome A [0000-0002-3284-5169], Michaut, Chloé [0000-0002-2578-0117], and Apollo - University of Cambridge Repository
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mantle convection ,Mechanics of Materials ,Mechanical Engineering ,Applied Mathematics ,suspensions ,magma and lava flow ,Condensed Matter Physics - Abstract
Convection within planetary bodies is often modelled using a temperature-dependent rheology which, when cooled from the surface, naturally leads to the formation of a so-called stagnant lid at the cold outer surface. However, for sufficiently large planets the phase diagram describing the partially molten system may depend significantly on pressure in addition to temperature, leading to significant variations in solid fraction. The aggregate rheology may therefore exhibit significant dependence on both the temperature and pressure, and hence may exhibit marked dependence on depth in addition to the dependence on the thermal structure due to convection. Here, we consider the growth and stability of a planetary stagnant lid. We first characterise the effect of a pressure- and temperature-dependent rheology on the evolution of a symmetric, planetary stagnant lid. This analysis further suggests that the pressure dependence of the rheology may lead to an instability of the growing stagnant lid which, importantly, may lead to asymmetric lid growth. We find that the most unstable mode is at the longest wavelengths, and discuss the implications for stagnant-lid convection and the growth of asymmetric surfaces of planetary bodies. In particular, we discuss the possibility that this instability has implications for the formation of the crustal dichotomy found on the Moon.
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- 2022
9. Acoustic sorting of microfluidic droplets at kHz rates using optical absorbance
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Richter, Esther S, Link, Andreas, McGrath, John S, Sparrow, Raymond W, Gantz, Maximilian, Medcalf, Elliot J, Hollfelder, Florian, Franke, Thomas, Richter, Esther S [0000-0001-5157-140X], Link, Andreas [0000-0002-1141-2831], McGrath, John S [0000-0001-9110-7759], Hollfelder, Florian [0000-0002-1367-6312], Franke, Thomas [0000-0001-5018-7545], Apollo - University of Cambridge Repository, and Apollo-University Of Cambridge Repository
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Spectrum Analysis ,Microfluidics ,Biomedical Engineering ,Bioengineering ,Acoustics ,General Chemistry ,Microfluidic Analytical Techniques ,Coloring Agents ,Oils ,Biochemistry - Abstract
Acknowledgements: This work is part of a project that has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 813786 (EVOdrops). This work reflects only the author's view, and the Research Executive Agency is not responsible for any use that may be made of the information it contains. It was supported by a studentship from the BBSRC Doctoral Training Account, (E. J. M., BB/M011194/1), a Trinity College/Benn W Levy SBS DTP PhD Studentship (M. G.) and an H2020 ERC Advanced Investigator Award (F. H., 695669)., Droplet microfluidics allows one to address the ever-increasing demand to screen large libraries of biological samples. Absorbance spectroscopy complements the golden standard of fluorescence detection by label free target identification and providing more quantifiable data. However, this is limited by speed and sensitivity. In this paper we increase the speed of sorting by including acoustofluidics, achieving sorting rates of target droplets of 1 kHz. We improved the device design for detection of absorbance using fibre-based interrogation of samples with integrated lenses in the microfluidic PDMS device for focusing and collimation of light. This optical improvement reduces the scattering and refraction artefacts, improving the signal quality and sensitivity. The novel design allows us to overcome limitations based on dielectrophoresis sorting, such as droplet size dependency, material and dielectric properties of samples. Our acoustic activated absorbance sorter removes the need for offset dyes or matching oils and sorts about a magnitude faster than current absorbance sorters.
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- 2022
10. Well-posedness of an integro-differential model for active Brownian particles
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Maria Bruna, Martin Burger, Antonio Esposito, Simon Schulz, Apollo-University Of Cambridge Repository, University Of Cambridge, Bruna Estrach, Maria [0000-0001-7829-5652], and Apollo - University of Cambridge Repository
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Computational Mathematics ,Mathematics - Analysis of PDEs ,Applied Mathematics ,FOS: Mathematics ,35K20, 35K58, 35Q70, 35Q92 ,Analysis ,math.AP ,Analysis of PDEs (math.AP) - Abstract
We propose a general strategy for solving nonlinear integro-differential evolution problems with periodic boundary conditions, where no direct maximum/minimum principle is available. This is motivated by the study of recent macroscopic models for active Brownian particles with repulsive interactions, consisting of advection-diffusion processes in the space of particle position and orientation. We focus on one of such models, namely a semilinear parabolic equation with a nonlinear active drift term, whereby the velocity depends on the particle orientation and angle-independent overall particle density (leading to a nonlocal term by integrating out the angular variable). The main idea of the existence analysis is to exploit a-priori estimates from (approximate) entropy dissipation. The global existence and uniqueness of weak solutions is shown using a two-step Galerkin approximation with appropriate cutoff in order to obtain nonnegativity, an upper bound on the overall density and preserve a-priori estimates. Our anyalysis naturally includes the case of finite systems, corresponding to the case of a finite number of directions. The Duhamel principle is then used to obtain additional regularity of the solution, namely continuity in time-space. Motivated by the class of initial data relevant for the application, which includes perfectly aligned particles (same orientation), we extend the well-posedness result to very weak solutions allowing distributional initial data with low regularity., Comment: 35 pages
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- 2022
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11. Witnessing quantum correlations in a nuclear ensemble via an electron spin qubit
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Daniel M. Jackson, Leon Zaporski, J. H. Bodey, Claire Le Gall, Maxime Hugues, Clara Bachorz, Dorian Gangloff, Gabriel Ethier-Majcher, Edmund Clarke, Constantin Lang, Mete Atatüre, Gangloff, DA [0000-0002-7100-0847], Zaporski, L [0000-0002-4543-6946], Bodey, JH [0000-0002-4067-1613], Jackson, DM [0000-0003-2001-6619], Clarke, E [0000-0002-8287-0282], Le Gall, C [0000-0002-8980-9628], Atatüre, M [0000-0003-3852-0944], Apollo - University of Cambridge Repository, and Apollo-University Of Cambridge Repository
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Physics ,Quantum Physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Spin states ,FOS: Physical sciences ,General Physics and Astronomy ,02 engineering and technology ,Quantum entanglement ,5104 Condensed Matter Physics ,021001 nanoscience & nanotechnology ,01 natural sciences ,5108 Quantum Physics ,Quantum dot ,Qubit ,Quantum mechanics ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,0103 physical sciences ,Quasiparticle ,Quantum Physics (quant-ph) ,010306 general physics ,0210 nano-technology ,Spin (physics) ,51 Physical Sciences ,Quantum ,Entanglement witness - Abstract
A coherent ensemble of spins interfaced with a proxy qubit is an attractive platform to create many-body coherences and probe the regime of collective excitations. An electron spin qubit in a semiconductor quantum dot can act as such an interface to the dense nuclear spin ensemble within the quantum dot consisting of multiple high-spin atomic species. Earlier work has shown that the electron can relay properties of its nuclear environment through the statistics of its mean-field interaction with the total nuclear polarization, namely its mean and variance. Here, we demonstrate a method to probe the spin state of a nuclear ensemble that exploits its response to collective spin excitations, enabling a species-selective reconstruction beyond the mean field. For the accessible range of optically prepared mean fields, the reconstructed populations indicate that the ensemble is in a non-thermal, correlated nuclear state. The sum over reconstructed species-resolved polarizations exceeds the classical prediction threefold. This stark deviation follows from a spin ensemble that contains inter-particle coherences, and serves as an entanglement witness that confirms the formation of a dark many-body state. Atoms in a semiconductor can have non-zero nuclear spins, creating a large ensemble with many quantum degrees of freedom. An electron spin coupled to the nuclei of a semiconductor quantum dot can witness the creation of entanglement within the ensemble.
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- 2021
12. A Journey to the West: The Ancient Dispersal of Rice Out of East Asia
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Li Tang, Hongen Jiang, Alisher Begmatov, Daniel Fuks, Rasmus Bjørn, Robert N. Spengler, Luca M. Olivieri, Sören Stark, Xinying Zhou, Basira Mir-Makhamad, Nicole Boivin, Spengler, Robert N [0000-0002-5648-6930], Apollo - University of Cambridge Repository, Apollo-University Of Cambridge Repository, and Spengler, Robert N., III [0000-0002-5648-6930]
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010506 paleontology ,South asia ,Agricultural intensification ,Archaeobotany ,Crop exchange ,Paddy farming ,Rice ,West Asia ,Soil Science ,Plant Science ,Review ,01 natural sciences ,SB1-1110 ,Paleoethnobotany ,0601 history and archaeology ,East Asia ,Domestication ,0105 earth and related environmental sciences ,2. Zero hunger ,060102 archaeology ,business.industry ,Plant culture ,06 humanities and the arts ,Arid ,Geography ,Agriculture ,Settore L-OR/16 - Archeologia e Storia Dell'Arte Dell'India e dell'Asia Centrale ,Biological dispersal ,Ethnology ,business ,Agronomy and Crop Science - Abstract
Rice is one of the most culturally valued and widely grown crops in the world today, and extensive research over the past decade has clarified much of the narrative of its domestication and early spread across East and South Asia. However, the timing and routes of its dispersal into West Asia and Europe, through which rice eventually became an important ingredient in global cuisines, has remained less clear. In this article, we discuss the piecemeal, but growing, archaeobotanical data for rice in West Asia. We also integrate written sources, linguistic data, and ethnohistoric analogies, in order to better understand the adoption of rice outside its regions of origin. The human-mediated westward spread of rice proceeded gradually, while its social standing and culinary uses repeatedly changing over time and place. Rice was present in West Asia and Europe by the tail end of the first millennium BC, but did not become a significant crop in West Asia until the past few centuries. Complementary historical, linguistic, and archaeobotanical data illustrate two separate and roughly contemporaneous routes of westward dispersal, one along the South Asian coast and the other through Silk Road trade. By better understanding the adoption of this water-demanding crop in the arid regions of West Asia, we explore an important chapter in human adaptation and agricultural decision making. Introduction Domestication - East Asia - South Asia Himalayan Plateau West and Central Asia - Historical Sources - Archaeobotanical Data South Asian Coastal Routes - Historical Sources - Archaeobotanical Data Intensification of Rice Cultivation Culinary Shift Conclusions
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- 2021
13. Surface reduction in lithium- and manganese-rich layered cathodes for lithium ion batteries drives voltage decay
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Wen, Bo, Sayed, Farheen N, Dose, Wesley M, Morzy, Jędrzej K, Son, Yeonguk, Nagendran, Supreeth, Ducati, Caterina, Grey, Clare P, De Volder, Michael FL, Wen, Bo [0000-0002-5860-649X], Sayed, Farheen N [0000-0002-5700-5959], Dose, Wesley M [0000-0003-3850-0505], Morzy, Jędrzej K [0000-0003-0770-461X], Grey, Clare P [0000-0001-5572-192X], De Volder, Michael FL [0000-0003-1955-2270], Apollo - University of Cambridge Repository, and Apollo-University Of Cambridge Repository
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34 Chemical Sciences ,Renewable Energy, Sustainability and the Environment ,3406 Physical Chemistry ,General Materials Science ,7 Affordable and Clean Energy ,General Chemistry ,4016 Materials Engineering ,40 Engineering - Abstract
Li- and Mn-rich layered oxides (Li1.2Ni0.2Mn0.6O2) are actively pursued as high energy and sustainable alternatives to the current Li-ion battery cathodes that contain Co. However, the severe decay in discharge voltage observed in these cathodes needs to be addressed before they can find commercial applications. A few mechanisms differing in origin have been proposed to explain the voltage fade, which may be caused by differences in material composition, morphology and electrochemical testing protocols. Here, these challenges are addressed by synthesising Li1.2Ni0.2Mn0.6O2 using three different hydrothermal and solid-state approaches and studying their degradation using the same cell design and cycling protocols. The voltage fade is found to be similar under the same electrochemical testing protocols, regardless of the synthesis method. X-ray absorption near edge, extended X-ray absorption fine structure spectroscopies, and energy loss spectroscopy in a scanning transmission electron microscope indicate only minor changes in the bulk Mn oxidation state but reveal a much more reduced particle surface upon extended cycling. No spinel phase is seen via the bulk structural characterisation methods of synchrotron X-ray diffraction, 7Li magic angle spinning solid state nuclear magnetic resonance and Raman spectroscopy. Thus, the voltage fade is believed to largely result from a heavily reduced particle surface. This hypothesis is further confirmed by galvanostatic intermittent titration technique analysis, which indicates that only very small shifts in equilibrium potential take place, in contrast to the overpotential which builds up after cycling. This suggests that a major source of the voltage decay is kinetic in origin, resulting from a heavily reduced particle surface with slow Li transport.
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- 2022
14. Environmental Impacts of Large-Scale Spirulina (Arthrospira platensis) Production in Hellisheidi Geothermal Park Iceland: Life Cycle Assessment
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Asaf Tzachor, Asger Smidt-Jensen, Alfons Ramel, Margrét Geirsdóttir, Apollo-University Of Cambridge Repository, and Apollo - University of Cambridge Repository
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Life Cycle Stages ,Research ,Iceland ,Water ,Vitamins ,Carbon Dioxide ,Environment ,Applied Microbiology and Biotechnology ,Carbon ,Carbon neutrality ,Environmental impact ,Photobioreactors ,Life cycle assessment ,Ammonia ,Spirulina ,Animals ,Cattle ,Amino Acids, Essential ,Biomass ,Fertilizers ,Alternative protein - Abstract
Spirulina algae (Spirulina platensis) cultivated in geothermally powered photobioreactors is here proposed as a potentially resource efficient, zero-carbon, and nutritious alternative to conventional beef meat. Employing a standard life cycle assessment, environmental impacts of large-scale Spirulina production in this facility are calculated. The production facility is sited in Orka náttúrunnar (ON Power) Geothermal Park, Iceland, and benefits from resource streams accessible through Hellisheiði (Hellisheidi) power station, including renewable electricity for illumination and power usage, hot and cold water streams for thermal management, freshwater for cultivation, and CO2 for biofixation. During cultivation, GHG-intensive ammonia-based fertilizers are replaced with macronutrients sourced from natural open mines. LCA results show that production of 1 kg of wet edible biomass in this facility requires 0.0378 m2 non-arable land, 8.36 m3 fresh water and is carbon neutral with − 0.008 CO2-eq GHG emissions (net zero). Compared with conventionally produced meat from beef cattle, Spirulina algae cultured in the ON Power Geothermal Park, referred to in this study as GeoSpirulina, requires less than 1% land and water and emits less than 1% GHGs. Considering food and nutritional security concerns, cultivation in a controlled environment agriculture system assures consistent nutritional profile year-round. Moreover, GeoSpirulina biomass assessed in this study contains all essential amino acids as well as essential vitamins and minerals. While keeping a balanced nutrition, for every kg beef meat replaced with one kg GeoSpirulina, the average consumer can save ~ 100 kg CO2-eq GHGs. It is concluded that environmental impacts of GeoSpirulina production in the Hellisheidi facility are considerably lower than those of conventionally produced ruminants. Graphical abstract
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- 2022
15. Writing Around the Ancient Mediterranean: Practices and Adaptations
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Steele, Philippa, Boyes, Philip, Steele, Philippa, Boyes, Philip J, Steele, Philippa [0000-0003-3109-265X], Apollo - University of Cambridge Repository, and Apollo-University Of Cambridge Repository
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Writing in the ancient Mediterranean existed against a backdrop of very high levels of interaction and contact. In the societies around its shores, writing was a dynamic practice that could serve many purposes – from a tool used by elites to control resources and establish their power bases to a symbol of local identity and a means of conveying complex information and ideas. This volume presents a group of papers by members of the Contexts of and Relations between Early Writing Systems (CREWS) research team and visiting fellows, offering a range of different perspectives and approaches to problems of writing in the ancient Mediterranean. They focus on practices, viewing writing as something that people do within a wider social and cultural context, and on adaptations, considering the ways in which writing changed and was changed by the people using it., ERC Horizon 2020 grant 677758 CREWS
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- 2022
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16. 3D Printable Soft Sensory Fiber Networks for Robust and Complex Tactile Sensing
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Hardman, David, George Thuruthel, Thomas, Georgopoulou, Antonia, Clemens, Frank, Iida, Fumiya, Hardman, David [0000-0002-5102-0541], George Thuruthel, Thomas [0000-0003-0571-1672], Georgopoulou, Antonia [0000-0002-9892-250X], Clemens, Frank [0000-0001-8253-170X], Iida, Fumiya [0000-0001-9246-7190], Apollo - University of Cambridge Repository, Apollo-University Of Cambridge Repository, Editor: Santaniello, Tommaso, and Editor: Milani, Paolo
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machine learning ,Control and Systems Engineering ,Mechanical Engineering ,3D printing ,soft robotic sensors ,Electrical and Electronic Engineering ,Article - Abstract
Peer reviewed: True, The human tactile system is composed of multi-functional mechanoreceptors distributed in an optimized manner. Having the ability to design and optimize multi-modal soft sensory systems can further enhance the capabilities of current soft robotic systems. This work presents a complete framework for the fabrication of soft sensory fiber networks for contact localization, using pellet-based 3D printing of piezoresistive elastomers to manufacture flexible sensory networks with precise and repeatable performances. Given a desirable soft sensor property, our methodology can design and fabricate optimized sensor morphologies without human intervention. Extensive simulation and experimental studies are performed on two printed networks, comparing a baseline network to one optimized via an existing information theory based approach. Machine learning is used for contact localization based on the sensor responses. The sensor responses match simulations with tunable performances and good localization accuracy, even in the presence of damage and nonlinear material properties. The potential of the networks to function as capacitive sensors is also demonstrated.
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- 2022
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17. Effects of Molecular Encapsulation on the Photophysical and Charge Transport Properties of a Naphthalene Diimide Bithiophene Copolymer
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Stefano Pecorario, Jeroen Royakkers, Alberto D. Scaccabarozzi, Francesca Pallini, Luca Beverina, Hugo Bronstein, Mario Caironi, Pecorario, S, Royakkers, J, Scaccabarozzi, A, Pallini, F, Beverina, L, Bronstein, H, Caironi, M, Pecorario, Stefano [0000-0001-9217-550X], Royakkers, Jeroen [0000-0002-6827-0969], Beverina, Luca [0000-0002-6450-545X], Bronstein, Hugo [0000-0003-0293-8775], Caironi, Mario [0000-0002-0442-4439], Apollo - University of Cambridge Repository, Sensor Engineering, RS: FSE Sensor Engineering, and Apollo-University Of Cambridge Repository
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HIGH-MOBILITY ,3403 Macromolecular and Materials Chemistry ,POLYTHIOPHENE ,34 Chemical Sciences ,General Chemical Engineering ,TEXTURE ,General Chemistry ,AGGREGATION ,PERFORMANCE ,4016 Materials Engineering ,PI-CONJUGATED POLYMERS ,CELLS ,Materials Chemistry ,CHAIN ,printed electronics ,ELECTRON-TRANSPORT ,CRYSTALLINITY ,40 Engineering - Abstract
Engineering the molecular structure of conjugated polymers is key to advancing the field of organic electronics. In this work, we synthesized a molecularly encapsulated version of the naphthalene diimide bithiophene copolymer PNDIT2, which is among the most popular high charge mobility organic semiconductors in n-type field-effect transistors and non-fullerene acceptors in organic photovoltaic blends. The encapsulating macrocycles shield the bithiophene units while leaving the naphthalene diimide units available for intermolecular interactions. With respect to PNDIT2, the encapsulated counterpart displays an increased backbone planarity. Molecular encapsulation prevents preaggregation of the polymer chains in common organic solvents, while it permits π-stacking in the solid state and promotes thin film crystallinity through an intermolecular-lock mechanism. Consequently, n-type semiconducting behavior is retained in field-effect transistors, although charge mobility is lower than in PNDIT2 due to the absence of the fibrillar microstructure that originates from preaggregation in solution. Hence, molecularly encapsulating conjugated polymers represent a promising chemical strategy to tune the molecular interaction in solution and the backbone conformation and to consequently control the nanomorphology of casted films without altering the electronic structure of the core polymer.
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- 2022
18. Using network analysis to illuminate the intergenerational transmission of adversity
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Chad Lance Hemady, Lydia Gabriela Speyer, Janell Kwok, Franziska Meinck, G.J. Melendez-Torres, Deborah Fry, Bonnie Auyeung, Aja Louise Murray, Apollo-University Of Cambridge Repository, Speyer, Lydia Gabriela [0000-0001-9071-4020], and Apollo - University of Cambridge Repository
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Substance-Related Disorders ,Infant, Newborn ,Infant ,preterm birth ,neonatal health ,ALSPAC ,low birthweight ,maternal health ,intergenerational transmission of adversity ,pairwise Markov Random Field models ,maternal adverse childhood experiences ,Adverse Childhood Experiences ,Pregnancy ,Risk Factors ,Intergenerational transmission of adversity ,Humans ,Premature Birth ,Female ,Longitudinal Studies ,Child ,network analysis - Abstract
Funder: Academy/Wolfson Foundation Fellowship, Funder: Data Driven Innovation Initiative, Funder: University of Bristol, Funder: European Research Council, UNLABELLED: Objective: The effects of maternal exposure to adverse childhood experiences (ACEs) may be transmitted to subsequent generations through various biopsychosocial mechanisms. However, studies tend to focus on exploring one or two focal pathways with less attention paid to links between different pathways. Using a network approach, this paper explores a range of core prenatal risk factors that may link maternal ACEs to infant preterm birth (PTB) and low birthweight (LBW). Methods: We used data from the Avon Longitudinal Study of Parents and Children (ALSPAC) (n = 8379) to estimate two mixed graphical network models: Model 1 was constructed using adverse infant outcomes, biopsychosocial and environmental risk factors, forms of ACEs, and sociodemographic factors. In Model 2, ACEs were combined to represent a threshold ACEs score (≥4). Network indices (i.e., shortest path and bridge expected influence [1-step & 2-step]) were estimated to determine the shortest pathway from ACEs to infant outcomes, and to identify the risk factors that are vital in activating other risk factors and adverse outcomes. Results: Network analyses estimated a mutually reinforcing web of childhood and prenatal risk factors, with each risk connected to at least two other risks. Bridge influence indices suggested that childhood physical and sexual abuse and multiple ACEs were highly interconnected to others risks. Overall, risky health behaviours during pregnancy (i.e., smoking & illicit drug use) were identified as 'active' risk factors capable of affecting (directly and indirectly) other risk factors and contributing to the persistent activation of the global risk network. These risks may be considered priority candidate targets for interventions to disrupt intergenerational risk transmission. Our study demonstrates the promise of network analysis as an approach for illuminating the intergenerational transmission of adversity in its full complexity. HIGHLIGHTS: We took a network approach to assessing links between ACEs and birth outcomes.ACEs, other prenatal risk factors, and birth outcomes had complex inter-connectionsHealth behaviours in pregnancy were indicated as optimal intervention targets.
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- 2022
19. The positive scalar curvature cobordism category
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Ebert, J, Randal-Williams, O, Apollo-University Of Cambridge Repository, University Of Cambridge, Randal-Williams, Oscar [0000-0002-7479-2878], and Apollo - University of Cambridge Repository
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Mathematics - Geometric Topology ,math.AT ,Mathematics::K-Theory and Homology ,Mathematics::Category Theory ,General Mathematics ,19K56, 53C27, 55P47, 55R35, 57R22, 57R65, 57R90, 58D17, 58D05, 58J20 ,FOS: Mathematics ,Algebraic Topology (math.AT) ,math.GT ,Geometric Topology (math.GT) ,Mathematics - Algebraic Topology ,Mathematics::Symplectic Geometry ,Mathematics::Algebraic Topology - Abstract
We prove that many spaces of positive scalar curvature metrics have the homotopy type of infinite loop spaces. Our result in particular applies to the path component of the round metric inside $\mathcal{R}^+ (S^d)$ if $d \geq 6$. To achieve that goal, we study the cobordism category of manifolds with positive scalar curvature. Under suitable connectivity conditions, we can identify the homotopy fibre of the forgetful map from the psc cobordism category to the ordinary cobordism category with a delooping of spaces of psc metrics. This uses a version of Quillen's Theorem B and instances of the Gromov--Lawson surgery theorem. We extend some of the surgery arguments by Galatius and the second named author to the psc setting to pass between different connectivity conditions. Segal's theory of $\Gamma$-spaces is then used to construct the claimed infinite loop space structures. The cobordism category viewpoint also illuminates the action of diffeomorphism groups on spaces of psc metrics. We show that under mild hypotheses on the manifold, the action map from the diffeomorphism group to the homotopy automorphisms of the spaces of psc metrics factors through the Madsen--Tillmann spectrum. This implies a strong rigidity theorem for the action map when the manifold has trivial rational Pontrjagin classes. A delooped version of the Atiyah--Singer index theorem proved by the first named author is used to moreover show that the secondary index invariant to real $K$-theory is an infinite loop map. These ideas also give a new proof of the main result of our previous work with Botvinnik., Comment: v2 98 pages. Accepted version, to appear in Duke Math. J
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- 2022
20. Identification of cis-acting determinants mediating the unconventional secretion of tau
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Thomas R. Jahn, Walter Nickel, William A. McEwan, Taxiarchis Katsinelos, Apollo - University of Cambridge Repository, McEwan, William [0000-0002-4408-0407], and Apollo-University Of Cambridge Repository
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0301 basic medicine ,Cell Membrane Permeability ,Science ,Cell ,631/80/2023 ,Hyperphosphorylation ,Fluorescent Antibody Technique ,tau Proteins ,CHO Cells ,Regulatory Sequences, Nucleic Acid ,Retina ,03 medical and health sciences ,0302 clinical medicine ,Cricetulus ,Microtubule ,Tandem Mass Spectrometry ,631/80/313/2376 ,medicine ,Extracellular ,Animals ,Secretion ,Cysteine ,Phosphorylation ,Secretory pathway ,Multidisciplinary ,Chemistry ,631/378/1689/1283 ,Gene Expression Profiling ,Cell Membrane ,article ,Alzheimer's disease ,medicine.disease ,Recombinant Proteins ,3. Good health ,Cell biology ,Transport protein ,Protein Transport ,030104 developmental biology ,medicine.anatomical_structure ,Drosophila melanogaster ,Gene Expression Regulation ,Medicine ,Tauopathy ,030217 neurology & neurosurgery ,Chromatography, Liquid - Abstract
The deposition of tau aggregates throughout the brain is a pathological characteristic within a group of neurodegenerative diseases collectively termed tauopathies, which includes Alzheimer’s disease. While recent findings suggest the involvement of unconventional secretory pathways driving tau into the extracellular space and mediating the propagation of the disease-associated pathology, many of the mechanistic details governing this process remain elusive. In the current study, we provide an in-depth characterization of the unconventional secretory pathway of tau and identify novel molecular determinants that are required for this process. Here, using Drosophila models of tauopathy, we correlate the hyperphosphorylation and aggregation state of tau with the disease-related neurotoxicity. These newly established systems recapitulate all the previously identified hallmarks of tau secretion, including the contribution of tau hyperphosphorylation as well as the requirement for PI(4,5)P2 triggering the direct translocation of tau. Using a series of cellular assays, we demonstrate that both the sulfated proteoglycans on the cell surface and the correct orientation of the protein at the inner plasma membrane leaflet are critical determinants of this process. Finally, we identify two cysteine residues within the microtubule binding repeat domain as novel cis-elements that are important for both unconventional secretion and trans-cellular propagation of tau.
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- 2021
21. Rational Passivation of Sulfur Vacancy Defects in Two-Dimensional Transition Metal Dichalcogenides
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Jack A. Alexander-Webber, Ye Fan, Steven G. Louie, Arelo Tanoh, Akshay Rao, Samuel D. Stranks, Géraud Delport, Stephan Hofmann, Sivan Refaely-Abramson, Cyan A. Williams, Hope M. Bretscher, Diana Y. Qiu, Jeffrey B. Neaton, Zhaojun Li, James Xiao, Bretscher, Hope [0000-0001-6551-4721], Qiu, Diana Yuan [0000-0003-3067-6987], Refaely-Abramson, Sivan [0000-0002-7031-8327], Alexander-Webber, Jack A [0000-0002-9374-7423], Tanoh, Arelo [0000-0003-2494-5984], Stranks, Samuel D [0000-0002-8303-7292], Hofmann, Stephan [0000-0001-6375-1459], Louie, Steven G [0000-0003-0622-0170], Rao, Akshay [0000-0003-4261-0766], Apollo - University of Cambridge Repository, and Apollo-University Of Cambridge Repository
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spectroscopy ,Materials science ,Photoluminescence ,Passivation ,Exciton ,General Physics and Astronomy ,Physics::Optics ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Article ,Condensed Matter::Materials Science ,defect engineering ,Transition metal ,Ab initio quantum chemistry methods ,Vacancy defect ,Monolayer ,General Materials Science ,Nanoscience & Nanotechnology ,Spectroscopy ,defects ,General Engineering ,many-body perturbation theory ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,2D materials ,0104 chemical sciences ,Chemical physics ,TMDC ,0210 nano-technology ,Den kondenserade materiens fysik - Abstract
Structural defects vary the optoelectronic properties of monolayer transition metal dichalcogenides, leading to concerted efforts to control defect type and density via materials growth or postgrowth passivation. Here, we explore a simple chemical treatment that allows on-off switching of low-lying, defect-localized exciton states, leading to tunable emission properties. Using steady-state and ultrafast optical spectroscopy, supported by ab initio calculations, we show that passivation of sulfur vacancy defects, which act as exciton traps in monolayer MoS2 and WS2, allows for controllable and improved mobilities and an increase in photoluminescence up to 275-fold, more than twice the value achieved by other chemical treatments. Our findings suggest a route for simple and rational defect engineering strategies for tunable and switchable electronic and excitonic properties through passivation.
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- 2021
22. Arabidopsis HEAT SHOCK FACTOR BINDING PROTEIN is required to limit meiotic crossovers and HEI10 transcription
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Juhyun Kim, Jihye Park, Heejin Kim, Namil Son, Eun‐Jung Kim, Jaeil Kim, Dohwan Byun, Youngkyung Lee, Yeong Mi Park, Divyashree C Nageswaran, Pallas Kuo, Teresa Rose, Tuong Vi T Dang, Ildoo Hwang, Christophe Lambing, Ian R Henderson, Kyuha Choi, Kim, Juhyun [0000-0001-5462-3391], Park, Jihye [0000-0002-9619-6575], Kim, Heejin [0000-0002-6144-775X], Son, Namil [0000-0003-4352-5627], Kim, Eun-Jung [0000-0003-4296-6826], Kim, Jaeil [0000-0001-8322-5624], Byun, Dohwan [0000-0002-1980-2252], Lee, Youngkyung [0000-0002-1451-6724], Park, Yeong Mi [0000-0002-1705-6356], Nageswaran, Divyashree C [0000-0001-7548-3244], Kuo, Pallas [0000-0001-5435-2026], Dang, Tuong Vi T [0000-0002-8042-0931], Hwang, Ildoo [0000-0002-9454-3326], Lambing, Christophe [0000-0001-5218-4217], Henderson, Ian R [0000-0001-5066-1489], Choi, Kyuha [0000-0002-4072-3807], Apollo - University of Cambridge Repository, and Apollo-University Of Cambridge Repository
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General Immunology and Microbiology ,Arabidopsis Proteins ,Chromosomal Proteins, Non-Histone ,General Neuroscience ,Ubiquitin-Protein Ligases ,HEI10 ,Arabidopsis ,Articles ,General Biochemistry, Genetics and Molecular Biology ,HSBP ,Meiosis ,HSF ,Crossover ,Crossing Over, Genetic ,Molecular Biology ,Heat-Shock Proteins ,Heat-Shock Response - Abstract
The number of meiotic crossovers is tightly controlled and most depend on pro-crossover ZMM proteins, such as the E3 ligase HEI10. Despite the importance of HEI10 dosage for crossover formation, how HEI10 transcription is controlled remains unexplored. In a forward genetic screen using a fluorescent crossover reporter in Arabidopsis thaliana, we identify heat shock factor binding protein (HSBP) as a repressor of HEI10 transcription and crossover numbers. Using genome-wide crossover mapping and cytogenetics, we show that hsbp mutations or meiotic HSBP knockdowns increase ZMM-dependent crossovers toward the telomeres, mirroring the effects of HEI10 overexpression. Through RNA sequencing, DNA methylome, and chromatin immunoprecipitation analysis, we reveal that HSBP is required to repress HEI10 transcription by binding with heat shock factors (HSFs) at the HEI10 promoter and maintaining DNA methylation over the HEI10 5' untranslated region. Our findings provide insights into how the temperature response regulator HSBP restricts meiotic HEI10 transcription and crossover number by attenuating HSF activity.
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- 2022
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23. Two electrolyte decomposition pathways at nickel-rich cathode surfaces in lithium-ion batteries
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Vivek J. Padmanabhan, Nuria Garcia-Araez, Bernardine Rinkel, Clare Grey, Apollo-University Of Cambridge Repository, Rinkel, Bernardine LD [0000-0003-4455-7313], Vivek, J Padmanabhan [0000-0002-6088-312X], Garcia-Araez, Nuria [0000-0001-9095-2379], Grey, Clare P [0000-0001-5572-192X], and Apollo - University of Cambridge Repository
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Nuclear Energy and Engineering ,34 Chemical Sciences ,Renewable Energy, Sustainability and the Environment ,3406 Physical Chemistry ,Environmental Chemistry ,Pollution ,4016 Materials Engineering ,40 Engineering - Abstract
Preventing the decomposition reactions of electrolyte solutions is essential for extending the lifetime of lithium-ion batteries. However, the exact mechanism(s) for electrolyte decomposition at the positive electrode, and particularly the soluble decomposition products that form and initiate further reactions at the negative electrode, are still largely unknown. In this work, a combination of operando gas measurements and solution NMR was used to study decomposition reactions of the electrolyte solution at NMC (LiNi xMn yCo 1−x−yO 2) and LCO (LiCoO 2) electrodes. A partially delithiated LFP (Li xFePO 4) counter electrode was used to selectively identify the products formed through processes at the positive electrodes. Based on the detected soluble and gaseous products, two distinct routes with different onset potentials are proposed for the decomposition of the electrolyte solution at NMC electrodes. At low potentials (80% SOC), 1O 2 released from the transition metal oxide chemically oxidises the electrolyte solvent (EC) to form CO 2, CO and H 2O. The formation of water via this mechanism was confirmed by reacting 17O-labelled 1O 2 with EC and characterising the reaction products via 1H and 17O NMR spectroscopy. The water that is produced initiates secondary reactions, leading to the formation of the various products identified by NMR spectroscopy. Noticeably fewer decomposition products were detected in NMC/graphite cells compared to NMC/Li xFePO 4 cells, which is ascribed to the consumption of water (from the reaction of 1O 2 and EC) at the graphite electrode, preventing secondary decomposition reactions. The insights on electrolyte decomposition mechanisms at the positive electrode, and the consumption of decomposition products at the negative electrode contribute to understanding the origin of capacity loss in NMC/graphite cells, and are hoped to support the development of strategies to mitigate the degradation of NMC-based cells.
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- 2022
24. Correcting a bias in the computation of behavioural time budgets that are based on supervised learning
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Resheff, Yehezkel S, Bensch, Hanna M, Zöttl, Markus, Rotics, Shay, Resheff, Yehezkel S [0000-0001-7863-7632], Bensch, Hanna M [0000-0002-8449-9843], Rotics, Shay [0000-0002-3858-1811], Apollo - University of Cambridge Repository, and Apollo-University Of Cambridge Repository
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Behavioural ecology ,body acceleration ,Ecological Modeling ,biotelemetry ,animal behaviour ,RESEARCH ARTICLES ,Movement ecology ,RESEARCH ARTICLE ,3109 Zoology ,machine learning ,biologging ,FOS: Biological sciences ,behavioural time budget ,Zoology ,Ecology, Evolution, Behavior and Systematics ,31 Biological Sciences - Abstract
This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by Wiley., 1. Supervised learning of behavioral modes from body-acceleration data has become a widely used research tool in Behavioral Ecology over the past decade. One of the primary usages of this tool is to estimate behavioral time budgets from the distribution of behaviors as predicted by the model. These serve as the key parameters to test predictions about the variation in animal behavior. In this paper we show that the widespread computation of behavioral time budgets is biased, due to ignoring the classification model confusion probabilities. 2. Next, we introduce the confusion matrix correction for time budgets - a simple correction method for adjusting the computed time budgets based on the model's confusion matrix. 3. Finally, we show that the proposed correction is able to eliminate the bias, both theoretically and empirically in a series of data simulations on body acceleration data of a fossorial rodent species (Damaraland mole-rat, Fukomys damarensis). 4. Our paper provides a simple implementation of the confusion matrix correction for time budgets, and we encourage researchers to use it to improve accuracy of behavioral time budget calculations.
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- 2022
25. Venture capital investments through the lens of network and functional data analysis
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Christian Esposito, Marco Gortan, Lorenzo Testa, Francesca Chiaromonte, Giorgio Fagiolo, Andrea Mina, Giulio Rossetti, Apollo-University Of Cambridge Repository, and Apollo - University of Cambridge Repository
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Social and Information Networks (cs.SI) ,FOS: Computer and information sciences ,Multidisciplinary ,G24 ,Computer Networks and Communications ,Research ,Computer Science - Social and Information Networks ,Statistics - Applications ,Venture capital ,Investment trajectory ,Computational Mathematics ,Functional data analysis ,C52 ,46 Information and Computing Sciences ,ddc:330 ,Applications (stat.AP) ,Network analysis ,4601 Applied Computing ,4006 Communications Engineering ,40 Engineering - Abstract
In this paper we characterize the performance of venture capital-backed firms based on their ability to attract investment. The aim of the study is to identify relevant predictors of success built from the network structure of firms' and investors' relations. Focusing on deal-level data for the health sector, we first create a bipartite network among firms and investors, and then apply functional data analysis (FDA) to derive progressively more refined indicators of success captured by a binary, a scalar and a functional outcome. More specifically, we use different network centrality measures to capture the role of early investments for the success of the firm. Our results, which are robust to different specifications, suggest that success has a strong positive association with centrality measures of the firm and of its large investors, and a weaker but still detectable association with centrality measures of small investors and features describing firms as knowledge bridges. Finally, based on our analyses, success is not associated with firms' and investors' spreading power (harmonic centrality), nor with the tightness of investors' community (clustering coefficient) and spreading ability (VoteRank)., Comment: 17 pages, 9 figures, supplementary material attached
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- 2022
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26. Composition-driven archetype dynamics in polyoxovanadates
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Kondinski, Aleksandar, Rasmussen, Maren, Mangelsen, Sebastian, Pienack, Nicole, Simjanoski, Viktor, Näther, Christian, Stares, Daniel L, Schalley, Christoph A, Bensch, Wolfgang, Kondinski, Aleksandar [0000-0002-0559-0172], Mangelsen, Sebastian [0000-0003-2121-9514], Simjanoski, Viktor [0000-0001-8686-2397], Näther, Christian [0000-0001-8741-6508], Stares, Daniel L [0000-0002-4497-6537], Schalley, Christoph A [0000-0002-8634-3578], Bensch, Wolfgang [0000-0002-3111-580X], Apollo - University of Cambridge Repository, and Apollo-University Of Cambridge Repository
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3402 Inorganic Chemistry ,molecular metal oxides ,34 Chemical Sciences ,General Chemistry ,500 Naturwissenschaften und Mathematik::540 Chemie::540 Chemie und zugeordnete Wissenschaften ,common structural frameworks ,polyoxovanadates - Abstract
Funder: Isaac Newton Trust, Funder: Alexander von Humboldt-Stiftung, Molecular metal oxides often adopt common structural frameworks (i.e. archetypes), many of them boasting impressive structural robustness and stability. However, the ability to adapt and to undergo transformations between different structural archetypes is a desirable material design feature offering applicability in different environments. Using systems thinking approach that integrates synthetic, analytical and computational techniques, we explore the transformations governing the chemistry of polyoxovanadates (POVs) constructed of arsenate and vanadate building units. The water-soluble salt of the low nuclearity polyanion [V6As8O26]4- can be effectively used for the synthesis of the larger spherical (i.e. kegginoidal) mixed-valent [V12As8O40]4- precipitate, while the novel [V10As12O40]8- POVs having tubular cyclic structures are another, well soluble product. Surprisingly, in contrast to the common observation that high-nuclearity polyoxometalate (POM) clusters are fragmented to form smaller moieties in solution, the low nuclearity [V6As8O26]4- anion is in situ transformed into the higher nuclearity cluster anions. The obtained products support a conceptually new model that is outlined in this article and that describes a continuous evolution between spherical and cyclic POV assemblies. This new model represents a milestone on the way to rational and designable POV self-assemblies.
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- 2022
27. Beneath the surface: Amino acid variation underlying two decades of dengue virus antigenic dynamics in Bangkok, Thailand
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Angkana T. Huang, Henrik Salje, Ana Coello Escoto, Nayeem Chowdhury, Christian Chávez, Bernardo Garcia-Carreras, Wiriya Rutvisuttinunt, Irina Maljkovic Berry, Gregory D. Gromowski, Lin Wang, Chonticha Klungthong, Butsaya Thaisomboonsuk, Ananda Nisalak, Luke M. Trimmer-Smith, Isabel Rodriguez-Barraquer, Damon W. Ellison, Anthony R. Jones, Stefan Fernandez, Stephen J. Thomas, Derek J. Smith, Richard Jarman, Stephen S. Whitehead, Derek A. T. Cummings, Leah C. Katzelnick, Huang, Angkana [0000-0002-9857-3506], Smith, Derek [0000-0002-2393-1890], Katzelnick, Leah C [0000-0003-1033-6758], Apollo - University of Cambridge Repository, Lowen, Anice C, Apollo-University Of Cambridge Repository, Editor: Lowen, Anice C., and Huang, Angkana T [0000-0002-9857-3506]
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FOS: Computer and information sciences ,Immunology ,Antibodies, Viral ,Microbiology ,Antibodies ,Dengue ,Vaccine Related ,Epitopes ,Viral Envelope Proteins ,Biodefense ,Virology ,Monoclonal ,Genetics ,Animals ,Viral ,Amino Acids ,Molecular Biology ,Neutralizing ,Medicine and health sciences ,Computer and information sciences ,Biology and life sciences ,Prevention ,Antibodies, Monoclonal ,Dengue Virus ,Thailand ,Antibodies, Neutralizing ,Vector-Borne Diseases ,Emerging Infectious Diseases ,Infectious Diseases ,Good Health and Well Being ,Medical Microbiology ,Parasitology ,Infection ,Research Article - Abstract
Funder: Division of Intramural Research, National Institute of Allergy and Infectious Diseases, Funder: Military Infectious Disease Research Program, Funder: Armed Forces Health Surveillance Branch, Neutralizing antibodies are important correlates of protection against dengue. Yet, determinants of variation in neutralization across strains within the four dengue virus serotypes (DENV1-4) is imperfectly understood. Studies focus on structural DENV proteins, especially the envelope (E), the primary target of anti-DENV antibodies. Although changes in immune recognition (antigenicity) are often attributed to variation in epitope residues, viral processes influencing conformation and epitope accessibility also affect neutralizability, suggesting possible modulating roles of nonstructural proteins. We estimated effects of residue changes in all 10 DENV proteins on antigenic distances between 348 DENV collected from individuals living in Bangkok, Thailand (1994-2014). Antigenic distances were derived from response of each virus to a panel of twenty non-human primate antisera. Across 100 estimations, excluding 10% of virus pairs each time, 77 of 295 positions with residue variability in E consistently conferred antigenic effects; 52 were within ±3 sites of known binding sites of neutralizing human monoclonal antibodies, exceeding expectations from random assignments of effects to sites (p = 0.037). Effects were also identified for 16 sites on the stem/anchor of E which were only recently shown to become exposed under physiological conditions. For all proteins, except nonstructural protein 2A (NS2A), root-mean-squared-error (RMSE) in predicting distances between pairs held out in each estimation did not outperform sequences of equal length derived from all proteins or E, suggesting that antigenic signals present were likely through linkage with E. Adjusted for E, we identified 62/219 sites embedding the excess signals in NS2A. Concatenating these sites to E additionally explained 3.4% to 4.0% of observed variance in antigenic distances compared to E alone (50.5% to 50.8%); RMSE outperformed concatenating E with sites from any protein of the virus (ΔRMSE, 95%IQR: 0.01, 0.05). Our results support examining antigenic determinants beyond the DENV surface.
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- 2022
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28. Study protocol comparing the ethical, psychological and socio-economic impact of personalised breast cancer screening to that of standard screening in the 'My Personal Breast Screening' (MyPeBS) randomised clinical trial
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Alexandra Roux, Rachel Cholerton, Jonathan Sicsic, Nora Moumjid, David P. French, Paolo Giorgi Rossi, Corinne Balleyguier, Michal Guindy, Fiona J. Gilbert, Jean-Benoit Burrion, Xavier Castells, David Ritchie, Debbie Keatley, Camille Baron, Suzette Delaloge, Sandrine de Montgolfier, Gilbert, Fiona [0000-0002-0124-9962], Apollo - University of Cambridge Repository, Apollo-University Of Cambridge Repository, Malbec, Odile, Institut de Recherche Interdisciplinaire sur les enjeux Sociaux - sciences sociales, politique, santé (IRIS), École des hautes études en sciences sociales (EHESS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Sorbonne Paris Nord, University of Manchester [Manchester], Laboratoire Interdisciplinaire de Recherche Appliquée en Economie de la Santé (LIRAES (URP_ 4470)), Université Paris Cité (UPCité), Parcours santé systémique (P2S), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Centre Léon Bérard [Lyon], Azienda Unità Sanitaria Locale di Bologna (AUSL), Institut Gustave Roussy (IGR), Imagerie thérapeutique (radiologie interventionnelle), Département d'imagerie médicale [Gustave Roussy], Institut Gustave Roussy (IGR)-Institut Gustave Roussy (IGR), Ben-Gurion University of the Negev (BGU), University of Cambridge [UK] (CAM), Institut Jules Bordet [Bruxelles], Faculté de Médecine [Bruxelles] (ULB), Université libre de Bruxelles (ULB)-Université libre de Bruxelles (ULB), IMIM-Hospital del Mar, Generalitat de Catalunya, European Cancer Leagues [Brussels, Belgium] (ECL), Independent Cancer Patients' Voice [London, UK] (ICPV), UNICANCER [Paris], Fédération nationale des Centres de lutte contre le Cancer (FNCLCC), Pathologie mammaire, and Département de médecine oncologique [Gustave Roussy]
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Adult ,Cancer Research ,[SDV]Life Sciences [q-bio] ,Satisfaction ,Breast Neoplasms ,Middle Aged ,Inequity ,Risk-stratification ,[SDV] Life Sciences [q-bio] ,Study Protocol ,Oncology ,Socioeconomic Factors ,Genetics ,Quality of Life ,Humans ,Mass Screening ,Female ,Underserved populations ,Breast cancer screening ,Comprehension ,Psychological impact ,Early Detection of Cancer ,Aged ,Randomized Controlled Trials as Topic - Abstract
Background: the MyPeBS study is an ongoing randomised controlled trial testing whether a risk-stratified breast cancer screening strategy is non-inferior, or eventually superior, to standard age-based screening at reducing incidence of stage 2 or more cancers. This large European Commission-funded initiative aims to include 85,000 women aged 40 to 70 years, without prior breast cancer and not previously identified at high risk in six countries (Belgium, France, Italy, Israel, Spain, UK). A specific work package within MyPeBS examines psychological, socio-economic and ethical aspects of this new screening strategy. It compares women's reported data and outcomes in both trial arms on the following issues: general anxiety, cancer-related worry, understanding of breast cancer screening strategy and information-seeking behaviour, socio-demographic and economic characteristics, quality of life, risk perception, intention to change health-related behaviours, satisfaction with the trial. Methods: at inclusion, 3-months, 1-year and 4-years, each woman participating in MyPeBS is asked to fill online questionnaires. Descriptive statistics, bivariate analyses, subgroup comparisons and analysis of variations over time will be performed with appropriate tests to assess differences between arms. Multivariate regression models will allow modelling of different patient reported data and outcomes such as comprehension of the information provided, general anxiety or cancer worry, and information seeking behaviour. In addition, a qualitative study (48 semi-structured interviews conducted in France and in the UK with women randomised in the risk-stratified arm), will help further understand participants' acceptability and comprehension of the trial, and their experience of risk assessment. Discussion: beyond the scientific and medical objectives of this clinical study, it is critical to acknowledge the consequences of such a paradigm shift for women. Indeed, introducing a risk-based screening relying on individual biological differences also implies addressing non-biological differences (e.g. social status or health literacy) from an ethical perspective, to ensure equal access to healthcare. The results of the present study will facilitate making recommendations on implementation at the end of the trial to accompany any potential change in screening strategy. MyPeBS project is funded by the European Union’s Horizon 2020 research and innovation programme under grant agreement N°755394 and underwent a full external peer review process at this step. MyPeBS has received funding from the PHRC-K research-funding programme (17–154) for the conduct of the study in France. DPF is supported by the NIHR Biomedical Research Centre in Manchester (IS-BRC-1215–20007). FJG is supported by the NIHR Cambridge Biomedical Research Centre (BRC-1215–20014). The views expressed are those of the authors and not necessarily those of the NHS, the NIHR, or the Department of Health and Social Care. XC is supported by grants from Instituto de Salud Carlos III FEDER (PI19/00007). MyPeBS is supported by the French health insurance systems (CNAM, MSA, MGEN, CPRPSNCF) for the covering of screening exams extra-costs, and by the Malakoff Humanis social protection group through the financing of the equipment of the recruiting centres with digital tablets to inform women about the study.
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- 2022
29. Strategies for sample labelling and library preparation in DNA metabarcoding studies
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Christian Carøe, Douglas W. Yu, Alex J. Dumbrell, Michael Bunce, Kristine Bohmann, Vasco Elbrecht, Florian Leese, Iliana Bista, Mathew Seymour, Simon Creer, Bohmann, Kristine [0000-0001-7907-064X], Elbrecht, Vasco [0000-0003-4672-7099], Carøe, Christian [0000-0001-9601-6768], Leese, Florian [0000-0002-5465-913X], Bunce, Michael [0000-0002-0302-4206], Yu, Douglas W [0000-0001-8551-5609], Seymour, Mathew [0000-0002-3654-4857], Dumbrell, Alex J [0000-0001-6282-3043], Creer, Simon [0000-0003-3124-3550], Apollo - University of Cambridge Repository, and Apollo-University Of Cambridge Repository
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0106 biological sciences ,Computer science ,Library preparation ,Sample (statistics) ,Computational biology ,Biology ,010603 evolutionary biology ,01 natural sciences ,Polymerase Chain Reaction ,DNA sequencing ,03 medical and health sciences ,Labelling ,Genetics ,DNA Barcoding, Taxonomic ,Environmental DNA ,Ecology, Evolution, Behavior and Systematics ,Illumina dye sequencing ,030304 developmental biology ,DNA Primers ,Gene Library ,0303 health sciences ,amplicon sequencing ,biodiversity assessment ,eDNA ,environmental DNA ,high-throughput sequencing ,Illumina sequencing ,library preparation ,high‐throughput sequencing ,Biodiversity ,Amplicon ,INVITED TECHNICAL REVIEW ,INVITED TECHNICAL REVIEWS ,Amplicon sequencing ,Biologie ,Biotechnology - Abstract
Metabarcoding of DNA extracted from environmental or bulk specimen samples is increasingly used to profile biota in basic and applied biodiversity research because of its targeted nature that allows sequencing of genetic markers from many samples in parallel. To achieve this, PCR amplification is carried out with primers designed to target a taxonomically informative marker within a taxonomic group, and sample-specific nucleotide identifiers are added to the amplicons prior to sequencing. The latter enables assignment of the sequences back to the samples they originated from. Nucleotide identifiers can be added during the metabarcoding PCR and during "library preparation", that is, when amplicons are prepared for sequencing. Different strategies to achieve this labelling exist. All have advantages, challenges and limitations, some of which can lead to misleading results, and in the worst case compromise the fidelity of the metabarcoding data. Given the range of questions addressed using metabarcoding, ensuring that data generation is robust and fit for the chosen purpose is critically important for practitioners seeking to employ metabarcoding for biodiversity assessments. Here, we present an overview of the three main workflows for sample-specific labelling and library preparation in metabarcoding studies on Illumina sequencing platforms; one-step PCR, two-step PCR, and tagged PCR. Further, we distill the key considerations for researchers seeking to select an appropriate metabarcoding strategy for their specific study. Ultimately, by gaining insights into the consequences of different metabarcoding workflows, we hope to further consolidate the power of metabarcoding as a tool to assess biodiversity across a range of applications., Molecular Ecology Resources, 22 (4), ISSN:1755-098X, ISSN:1471-8278, ISSN:1755-0998, ISSN:1471-8286
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- 2022
30. Proplyds in the flame nebula NGC 2024
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Cathie J. Clarke, Dean C. Hines, Giulia Ballabio, Thomas J. Haworth, Andrew J Winter, Karl R. Stapelfeldt, Andrew D Sellek, Jinyoung Serena Kim, Clarke, Catherine [0000-0003-4288-0248], Apollo - University of Cambridge Repository, and Apollo-University Of Cambridge Repository
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Population ,Continuum (design consultancy) ,FOS: Physical sciences ,Astrophysics ,circumstellar matter ,01 natural sciences ,galaxies: star clusters: individual: NGC 2024 ,accretion ,Planet ,0103 physical sciences ,education ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,Earth and Planetary Astrophysics (astro-ph.EP) ,Physics ,education.field_of_study ,Nebula ,010308 nuclear & particles physics ,Astronomy and Astrophysics ,Astrophysics - Astrophysics of Galaxies ,accretion discs ,Photoevaporation ,protoplanetary discs ,Accretion (astrophysics) ,Interstellar medium ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,galaxies: star formation ,Detection rate ,Astrophysics - Earth and Planetary Astrophysics - Abstract
A recent survey of the inner $0.35\times0.35$pc of the NGC 2024 star forming region revealed two distinct millimetre continuum disc populations that appear to be spatially segregated by the boundary of a dense cloud. The eastern (and more embedded) population is $\sim0.2-0.5$Myr old, with an ALMA mm continuum disc detection rate of about $45\,$per cent. However this drops to only $\sim15$per cent in the 1Myr western population. When presenting this result, van Terwisga et al. (2020) suggested that the two main UV sources, IRS 1 (a B0.5V star in the western region) and IRS 2b (an O8V star in the eastern region, but embedded) have both been evaporating the discs in the depleted western population. In this paper we report the firm discovery in archival HST data of 4 proplyds and 4 further candidate proplyds in NGC 2024, confirming that external photoevaporation of discs is occurring. However, the locations of these proplyds changes the picture. Only three of them are in the depleted western population and their evaporation is dominated by IRS 1, with no obvious impact from IRS 2b. The other 5 proplyds are in the younger eastern region and being evaporated by IRS 2b. We propose that both populations are subject to significant external photoevaporation, which happens throughout the region wherever discs are not sufficiently shielded by the interstellar medium. The external photoevaporation and severe depletion of mm grains in the 0.2-0.5Myr eastern part of NGC 2024 would be in competition even with very early planet formation., Comment: 14 pages, Accepted for publication in MNRAS
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- 2020
31. Microbial communities form rich extracellular metabolomes that foster metabolic interactions and promote drug tolerance
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Jason S. L. Yu, Clara Correia-Melo, Francisco Zorrilla, Lucia Herrera-Dominguez, Mary Y. Wu, Johannes Hartl, Kate Campbell, Sonja Blasche, Marco Kreidl, Anna-Sophia Egger, Christoph B. Messner, Vadim Demichev, Anja Freiwald, Michael Mülleder, Michael Howell, Judith Berman, Kiran R. Patil, Mohammad Tauqeer Alam, Markus Ralser, Yu, Jason SL [0000-0001-5203-3603], Correia-Melo, Clara [0000-0001-6062-1472], Herrera-Dominguez, Lucia [0000-0001-8276-2241], Wu, Mary Y [0000-0002-2074-6171], Hartl, Johannes [0000-0001-8470-5355], Egger, Anna-Sophia [0000-0002-5204-7121], Howell, Michael [0000-0003-0912-0079], Berman, Judith [0000-0002-8577-0084], Alam, Mohammad Tauqeer [0000-0002-6872-0691], Ralser, Markus [0000-0001-9535-7413], Apollo - University of Cambridge Repository, and Apollo-University Of Cambridge Repository
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Microbiology (medical) ,631/326/2565/855 ,RM ,Immunology ,Applied Microbiology and Biotechnology ,Microbiology ,82/80 ,13/44 ,14/34 ,Ecology,Evolution & Ethology ,38/47 ,Genetics ,14/35 ,Computational & Systems Biology ,Chemical Biology & High Throughput ,82/58 ,Microbiota ,article ,Cell Biology ,Drug Tolerance ,631/326/22 ,QP ,96/63 ,QR ,13/31 ,Metabolism ,Metabolome ,bacteria ,Microbial Interactions ,Synthetic Biology ,Metabolic Networks and Pathways - Abstract
Funder: United Arab Emirates University (UAEU); doi: https://doi.org/10.13039/501100006013, Microbial communities are composed of cells of varying metabolic capacity, and regularly include auxotrophs that lack essential metabolic pathways. Through analysis of auxotrophs for amino acid biosynthesis pathways in microbiome data derived from >12,000 natural microbial communities obtained as part of the Earth Microbiome Project (EMP), and study of auxotrophic-prototrophic interactions in self-establishing metabolically cooperating yeast communities (SeMeCos), we reveal a metabolically imprinted mechanism that links the presence of auxotrophs to an increase in metabolic interactions and gains in antimicrobial drug tolerance. As a consequence of the metabolic adaptations necessary to uptake specific metabolites, auxotrophs obtain altered metabolic flux distributions, export more metabolites and, in this way, enrich community environments in metabolites. Moreover, increased efflux activities reduce intracellular drug concentrations, allowing cells to grow in the presence of drug levels above minimal inhibitory concentrations. For example, we show that the antifungal action of azoles is greatly diminished in yeast cells that uptake metabolites from a metabolically enriched environment. Our results hence provide a mechanism that explains why cells are more robust to drug exposure when they interact metabolically.
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- 2022
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32. Geminate and Nongeminate Pathways for Triplet Exciton Formation in Organic Solar Cells
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Alberto Privitera, Jeannine Grüne, Akchheta Karki, William K. Myers, Vladimir Dyakonov, Thuc‐Quyen Nguyen, Moritz K. Riede, Richard H. Friend, Andreas Sperlich, Alexander J. Gillett, Apollo-University Of Cambridge Repository, University Of Cambridge, Gillett, AJ [0000-0001-7572-7333], and Apollo - University of Cambridge Repository
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Condensed Matter::Materials Science ,Renewable Energy, Sustainability and the Environment ,nonradiative recombination ,General Materials Science ,organic solar cells ,Physics::Chemical Physics ,triplet excitons - Abstract
Organic solar cells (OSCs) have recently shown a rapid improvement in their performance, bringing power conversion efficiencies to above 18%. However, the open‐circuit voltage of OSCs remains low relative to their optical gap and this currently limits efficiency. Recombination to spin‐triplet excitons is a key contributing factor, and is widely, but not universally, observed in donor–acceptor blends using both fullerene and nonfullerenes as electron acceptors. Here, an experimental framework that combines time‐resolved optical and magnetic resonance spectroscopies to detect triplet excitons and identify their formation mechanisms, is reported. The methodology is applied to two well‐studied polymer:fullerene systems, PM6:PC60BM and PTB7‐Th:PC60BM. In contrast to the more efficient nonfullerene acceptor systems that show only triplet states formed via nongeminate recombination, the fullerene systems also show significant triplet formation via geminate processes. This requires that geminate electron–hole pairs be trapped long enough to allow intersystem crossing. It is proposed that this is a general feature of fullerene acceptor systems, where isolated fullerenes are known to intercalate within the alkyl sidechains of the donor polymers. Thus, the study demonstrates that engineering good donor and acceptor domain purity is key for suppressing losses via triplet excitons in OSCs.
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- 2022
33. The EXPRES Stellar Signals Project II. State of the field in disentangling photospheric velocities
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Lily L. Zhao, Debra A. Fischer, Eric B. Ford, Alex Wise, Michaël Cretignier, Suzanne Aigrain, Oscar Barragan, Megan Bedell, Lars A. Buchhave, João D. Camacho, Heather M. Cegla, Jessi Cisewski-Kehe, Andrew Collier Cameron, Zoe L. de Beurs, Sally Dodson-Robinson, Xavier Dumusque, João P. Faria, Christian Gilbertson, Charlotte Haley, Justin Harrell, David W. Hogg, Parker Holzer, Ancy Anna John, Baptiste Klein, Marina Lafarga, Florian Lienhard, Vinesh Maguire-Rajpaul, Annelies Mortier, Belinda Nicholson, Michael L. Palumbo, Victor Ramirez Delgado, Christopher J. Shallue, Andrew Vanderburg, Pedro T. P. Viana, Jinglin Zhao, Norbert Zicher, Samuel H. C. Cabot, Gregory W. Henry, Rachael M. Roettenbacher, John M. Brewer, Joe Llama, Ryan R. Petersburg, Andrew E. Szymkowiak, Apollo-University Of Cambridge Repository, Zhao, LL [0000-0002-3852-3590], Fischer, DA [0000-0003-2221-0861], Ford, EB [0000-0001-6545-639X], Wise, A [0000-0002-5013-5769], Cretignier, M [0000-0002-2207-0750], Aigrain, S [0000-0003-1453-0574], Barragan, O [0000-0003-0563-0493], Bedell, M [0000-0001-9907-7742], Buchhave, LA [0000-0003-1605-5666], Camacho, JD [0000-0001-5121-5560], Cegla, HM [0000-0001-8934-7315], Cisewski-Kehe, J [0000-0002-9656-2272], Collier Cameron, A [0000-0002-8863-7828], De Beurs, ZL [0000-0002-7564-6047], Dodson-Robinson, S [0000-0002-8796-4974], Dumusque, X [0000-0002-9332-2011], Faria, JP [0000-0002-6728-244X], Gilbertson, C [0000-0002-1743-3684], Haley, C [0000-0003-3996-773X], Harrell, J [0000-0001-8936-6276], Hogg, DW [0000-0003-2866-9403], Holzer, P [0000-0001-8936-6276], John, AA [0000-0002-1715-6939], Klein, B [0000-0003-0637-5236], Lafarga, M [0000-0002-8815-9416], Lienhard, F [0000-0003-4047-0771], Maguire-Rajpaul, V [0000-0001-7576-6703], Mortier, A [0000-0001-7254-4363], Nicholson, B [0000-0003-1360-4404], Palumbo, ML [0000-0002-4677-8796], Ramirez Delgado, V [0000-0001-8183-459X], Shallue, CJ [0000-0002-7585-9974], Vanderburg, A [0000-0001-7246-5438], Viana, PTP [0000-0003-1572-8531], Zhao, J [0000-0001-5290-2952], Zicher, N [0000-0001-6143-2905], Cabot, SHC [0000-0001-9749-6150], Henry, GW [0000-0003-4155-8513], Roettenbacher, RM [0000-0002-9288-3482], Brewer, JM [0000-0002-9873-1471], Llama, J [0000-0003-4450-0368], Petersburg, RR [0000-0003-2168-0191], Szymkowiak, AE [0000-0002-4974-687X], Apollo - University of Cambridge Repository, Zhao, Lily L. [0000-0002-3852-3590], Fischer, Debra A. [0000-0003-2221-0861], Ford, Eric B. [0000-0001-6545-639X], Wise, Alex [0000-0002-5013-5769], Cretignier, Michaël [0000-0002-2207-0750], Aigrain, Suzanne [0000-0003-1453-0574], Barragan, Oscar [0000-0003-0563-0493], Bedell, Megan [0000-0001-9907-7742], Buchhave, Lars A. [0000-0003-1605-5666], Camacho, João D. [0000-0001-5121-5560], Cegla, Heather M. [0000-0001-8934-7315], Cisewski-Kehe, Jessi [0000-0002-9656-2272], Collier Cameron, Andrew [0000-0002-8863-7828], de Beurs, Zoe L. [0000-0002-7564-6047], Dodson-Robinson, Sally [0000-0002-8796-4974], Dumusque, Xavier [0000-0002-9332-2011], Faria, João P. [0000-0002-6728-244X], Gilbertson, Christian [0000-0002-1743-3684], Haley, Charlotte [0000-0003-3996-773X], Harrell, Justin [0000-0001-8936-6276], Hogg, David W. [0000-0003-2866-9403], Holzer, Parker [0000-0001-8936-6276], John, Ancy Anna [0000-0002-1715-6939], Klein, Baptiste [0000-0003-0637-5236], Lafarga, Marina [0000-0002-8815-9416], Lienhard, Florian [0000-0003-4047-0771], Maguire-Rajpaul, Vinesh [0000-0001-7576-6703], Mortier, Annelies [0000-0001-7254-4363], Nicholson, Belinda [0000-0003-1360-4404], Palumbo, Michael L., III [0000-0002-4677-8796], Ramirez Delgado, Victor [0000-0001-8183-459X], Shallue, Christopher J. [0000-0002-7585-9974], Vanderburg, Andrew [0000-0001-7246-5438], Viana, Pedro T. P. [0000-0003-1572-8531], Zhao, Jinglin [0000-0001-5290-2952], Zicher, Norbert [0000-0001-6143-2905], Cabot, Samuel H. C. [0000-0001-9749-6150], Henry, Gregory W. [0000-0003-4155-8513], Roettenbacher, Rachael M. [0000-0002-9288-3482], Brewer, John M. [0000-0002-9873-1471], Llama, Joe [0000-0003-4450-0368], Petersburg, Ryan R. [0000-0003-2168-0191], Szymkowiak, Andrew E. [0000-0002-4974-687X], Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science
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Radial velocity ,astro-ph.SR ,FOS: Physical sciences ,QB Astronomy ,Exoplanet detection methods ,Astrophysics::Solar and Stellar Astrophysics ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,Solar and Stellar Astrophysics (astro-ph.SR) ,QC ,Stellar activity ,QB ,Earth and Planetary Astrophysics (astro-ph.EP) ,MCC ,Spectrometers ,The Solar System, Exoplanets, and Astrobiology ,Astronomy and Astrophysics ,3rd-DAS ,QC Physics ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,astro-ph.EP ,Planet hosting stars ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics ,astro-ph.IM ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Measured spectral shifts due to intrinsic stellar variability (e.g., pulsations, granulation) and activity (e.g., spots, plages) are the largest source of error for extreme precision radial velocity (EPRV) exoplanet detection. Several methods are designed to disentangle stellar signals from true center-of-mass shifts due to planets. The EXPRES Stellar Signals Project (ESSP) presents a self-consistent comparison of 22 different methods tested on the same extreme-precision spectroscopic data from EXPRES. Methods derived new activity indicators, constructed models for mapping an indicator to the needed RV correction, or separated out shape- and shift-driven RV components. Since no ground truth is known when using real data, relative method performance is assessed using the total and nightly scatter of returned RVs and agreement between the results of different methods. Nearly all submitted methods return a lower RV RMS than classic linear decorrelation, but no method is yet consistently reducing the RV RMS to sub-meter-per-second levels. There is a concerning lack of agreement between the RVs returned by different methods. These results suggest that continued progress in this field necessitates increased interpretability of methods, high-cadence data to capture stellar signals at all timescales, and continued tests like the ESSP using consistent data sets with more advanced metrics for method performance. Future comparisons should make use of various well-characterized data sets -- such as solar data or data with known injected planetary and/or stellar signals -- to better understand method performance and whether planetary signals are preserved., 33 pages (+12 pages of Appendix), 10 figures, 8 tables, accepted for publication in AJ
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- 2022
34. From computational high-throughput screenings to the lab: taking metal-organic frameworks out of the computer
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Li, Aurelia, Bueno-Perez, Rocio, Madden, David, Fairen-Jimenez, David, Apollo-University Of Cambridge Repository, Li, Aurelia [0000-0001-8298-3992], Bueno-Perez, Rocio [0000-0002-1472-6852], Madden, David [0000-0003-3875-9146], Fairen-Jimenez, David [0000-0002-5013-1194], and Apollo - University of Cambridge Repository
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3403 Macromolecular and Materials Chemistry ,34 Chemical Sciences ,General Chemistry - Abstract
Metal-organic frameworks (MOFs) are one of the most researched designer materials today, as their high tunability offers scientists a wide space to imagine all kinds of possible structures. Their uniquely flexible customisability spurred the creation of hypothetical datasets and the syntheses of more than 100 000 MOFs officially reported in the Cambridge Structural Database. To scan such large numbers of MOFs, computational high-throughput screenings (HTS) have become the customary method to identify the most promising structure for a given application, and/or to spot useful structure-property relationships. However, despite all these data-mining efforts, only a fraction of HTS studies have identified synthesisable top-performing MOFs that were then further investigated in the lab. In this perspective, we review these specific cases and suggest possible steps to push future HTS more systematically towards synthesisable structures.
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- 2022
35. Multimodal correlative imaging and modelling of phosphorus uptake from soil by hyphae of mycorrhizal fungi
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Sam Keyes, Arjen Veelen, Dan McKay Fletcher, Callum Scotson, Nico Koebernick, Chiara Petroselli, Katherine Williams, Siul Ruiz, Laura Cooper, Robbie Mayon, Simon Duncan, Marc Dumont, Iver Jakobsen, Giles Oldroyd, Andrzej Tkacz, Philip Poole, Fred Mosselmans, Camelia Borca, Thomas Huthwelker, David L. Jones, Tiina Roose, Apollo-University Of Cambridge Repository, McKay Fletcher, Dan [0000-0001-6569-2931], Roose, Tiina [0000-0001-8744-2060], and Apollo - University of Cambridge Repository
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X-ray computed tomography ,X‐ray fluorescence ,Physiology ,fungi ,X-ray fluorescence ,Fungi ,Hyphae ,Phosphorus ,Plant Science ,mycorrhizas ,plant phosphorus uptake ,Plant Roots ,Full paper ,Full papers ,Soil ,X‐ray computed tomography ,rhizosphere modelling ,Mycorrhizae ,synchrotron ,Soil Microbiology - Abstract
Funder: U.S. Department of Energy through the LANL/LDRD Program, Funder: G. T. Seaborg Institute, Phosphorus (P) is essential for plant growth. Arbuscular mycorrhizal fungi (AMF) aid its uptake by acquiring P from sources distant from roots in return for carbon. Little is known about how AMF colonise soil pore-space, and models of AMF-enhanced P-uptake are poorly validated. We used synchrotron X-ray computed tomography to visualize mycorrhizas in soil and synchrotron X-ray fluorescence/X-ray absorption near edge structure (XRF/XANES) elemental mapping for P, sulphur (S) and aluminium (Al) in combination with modelling. We found that AMF inoculation had a suppressive effect on colonisation by other soil fungi and identified differences in structure and growth rate between hyphae of AMF and nonmycorrhizal fungi. Our results showed that AMF co-locate with areas of high P and low Al, and preferentially associate with organic-type P species over Al-rich inorganic P. We discovered that AMF avoid Al-rich areas as a source of P. Sulphur-rich regions were found to be correlated with higher hyphal density and an increased organic-associated P-pool, whilst oxidized S-species were found close to AMF hyphae. Increased S oxidation close to AMF suggested the observed changes were microbiome-related. Our experimentally-validated model led to an estimate of P-uptake by AMF hyphae that is an order of magnitude lower than rates previously estimated - a result with significant implications for the modelling of plant-soil-AMF interactions.
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- 2022
36. Associations between moderate alcohol consumption, brain iron, and cognition in UK Biobank participants: Observational and mendelian randomization analyses
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Anya Topiwala, Chaoyue Wang, Klaus P. Ebmeier, Stephen Burgess, Steven Bell, Daniel F. Levey, Hang Zhou, Celeste McCracken, Adriana Roca-Fernández, Steffen E. Petersen, Betty Raman, Masud Husain, Joel Gelernter, Karla L. Miller, Stephen M. Smith, Thomas E. Nichols, Topiwala, Anya [0000-0002-8408-0372], Wang, Chaoyue [0000-0001-9402-1563], Ebmeier, Klaus P [0000-0002-5190-7038], Burgess, Stephen [0000-0001-5365-8760], Bell, Steven [0000-0001-6774-3149], Levey, Daniel F [0000-0001-8431-9569], Zhou, Hang [0000-0002-7694-6391], McCracken, Celeste [0000-0003-1285-2393], Roca-Fernández, Adriana [0000-0002-8720-9397], Petersen, Steffen E [0000-0003-4622-5160], Husain, Masud [0000-0002-6850-9255], Gelernter, Joel [0000-0002-4067-1859], Nichols, Thomas E [0000-0002-4516-5103], Apollo - University of Cambridge Repository, and Apollo-University Of Cambridge Repository
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Medicine and health sciences ,Male ,Biology and life sciences ,Alcohol Drinking ,Iron ,Brain ,General Medicine ,Mendelian Randomization Analysis ,Middle Aged ,United Kingdom ,Research and analysis methods ,Alcoholism ,Cognition ,Humans ,Female ,Research Article ,Biological Specimen Banks - Abstract
Funder: BHF Centre of Research Excellence, Oxford, Funder: China Scholarship Council, Funder: Li Ka Shing Foundation, BACKGROUND: Brain iron deposition has been linked to several neurodegenerative conditions and reported in alcohol dependence. Whether iron accumulation occurs in moderate drinkers is unknown. Our objectives were to investigate evidence in support of causal relationships between alcohol consumption and brain iron levels and to examine whether higher brain iron represents a potential pathway to alcohol-related cognitive deficits. METHODS AND FINDINGS: Observational associations between brain iron markers and alcohol consumption (n = 20,729 UK Biobank participants) were compared with associations with genetically predicted alcohol intake and alcohol use disorder from 2-sample mendelian randomization (MR). Alcohol intake was self-reported via a touchscreen questionnaire at baseline (2006 to 2010). Participants with complete data were included. Multiorgan susceptibility-weighted magnetic resonance imaging (9.60 ± 1.10 years after baseline) was used to ascertain iron content of each brain region (quantitative susceptibility mapping (QSM) and T2*) and liver tissues (T2*), a marker of systemic iron. Main outcomes were susceptibility (χ) and T2*, measures used as indices of iron deposition. Brain regions of interest included putamen, caudate, hippocampi, thalami, and substantia nigra. Potential pathways to alcohol-related iron brain accumulation through elevated systemic iron stores (liver) were explored in causal mediation analysis. Cognition was assessed at the scan and in online follow-up (5.82 ± 0.86 years after baseline). Executive function was assessed with the trail-making test, fluid intelligence with puzzle tasks, and reaction time by a task based on the "Snap" card game. Mean age was 54.8 ± 7.4 years and 48.6% were female. Weekly alcohol consumption was 17.7 ± 15.9 units and never drinkers comprised 2.7% of the sample. Alcohol consumption was associated with markers of higher iron (χ) in putamen (β = 0.08 standard deviation (SD) [95% confidence interval (CI) 0.06 to 0.09], p < 0.001), caudate (β = 0.05 [0.04 to 0.07], p < 0.001), and substantia nigra (β = 0.03 [0.02 to 0.05], p < 0.001) and lower iron in the thalami (β = -0.06 [-0.07 to -0.04], p < 0.001). Quintile-based analyses found these associations in those consuming >7 units (56 g) alcohol weekly. MR analyses provided weak evidence these relationships are causal. Genetically predicted alcoholic drinks weekly positively associated with putamen and hippocampus susceptibility; however, these associations did not survive multiple testing corrections. Weak evidence for a causal relationship between genetically predicted alcohol use disorder and higher putamen susceptibility was observed; however, this was not robust to multiple comparisons correction. Genetically predicted alcohol use disorder was associated with serum iron and transferrin saturation. Elevated liver iron was observed at just >11 units (88 g) alcohol weekly c.f.
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- 2022
37. Breaking the Selection Rules of Spin-Forbidden Molecular Absorption in Plasmonic Nanocavities
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Rohit Chikkaraddy, Qianqi Lin, Oluwafemi Stephen Ojambati, Oren A. Scherman, Zsuzsanna Koczor-Benda, William M. Deacon, Charlie Readman, Jeremy J. Baumberg, Edina Rosta, Ojambati, OS [0000-0002-8028-4386], Chikkaraddy, R [0000-0002-3840-4188], Rosta, E [0000-0002-9823-4766], Scherman, OA [0000-0001-8032-7166], Baumberg, JJ [0000-0002-9606-9488], Apollo - University of Cambridge Repository, and Apollo-University Of Cambridge Repository
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Photoluminescence ,Materials science ,Organic solar cell ,Astrophysics::High Energy Astrophysical Phenomena ,resonant Raman ,Physics::Optics ,FOS: Physical sciences ,02 engineering and technology ,symmetry breaking ,7. Clean energy ,01 natural sciences ,010309 optics ,Physics - Chemical Physics ,spin mixing ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,0103 physical sciences ,Symmetry breaking ,Physics::Chemical Physics ,Electrical and Electronic Engineering ,Spin (physics) ,Absorption (electromagnetic radiation) ,Spectroscopy ,Plasmon ,Diode ,Chemical Physics (physics.chem-ph) ,Condensed Matter - Mesoscale and Nanoscale Physics ,021001 nanoscience & nanotechnology ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Chemical physics ,plasmonic nanocavity ,photoluminescence ,0210 nano-technology ,Physics - Optics ,Optics (physics.optics) ,Biotechnology - Abstract
Controlling absorption and emission of organic molecules is crucial for efficient light-emitting diodes, organic solar cells and single-molecule spectroscopy. Here, a new molecular absorption is activated inside a gold plasmonic nanocavity, and found to break selection rules via spin-orbit coupling. Photoluminescence excitation scans reveal absorption from a normally spin-forbidden singlet to triplet state transition, while drastically enhancing the emission rate by several thousand fold. The experimental results are supported by density functional theory, revealing the manipulation of molecular absorption by nearby metallic gold atoms., Comment: 8 pages, 4 figures
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- 2020
38. Thiol-Anchored TIPS-Tetracene Ligands with Quantitative Triplet Energy Transfer to PbS Quantum Dots and Improved Thermal Stability
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Victor Gray, Akshay Rao, Zhilong Zhang, Antonios M. Alvertis, Jesse R. Allardice, John E. Anthony, Neil C. Greenham, Simon Dowland, James Xiao, Gray, Victor [0000-0001-6583-8654], Zhang, Zhilong [0000-0001-9903-4945], Allardice, Jesse R [0000-0002-1969-7536], Alvertis, Antonios M [0000-0001-5916-3419], Greenham, Neil C [0000-0002-2155-2432], Anthony, John E [0000-0002-8972-1888], Rao, Akshay [0000-0003-4261-0766], Apollo - University of Cambridge Repository, and Apollo-University Of Cambridge Repository
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Imagination ,Chemical substance ,Materials science ,media_common.quotation_subject ,Physics::Optics ,02 engineering and technology ,010402 general chemistry ,Photochemistry ,01 natural sciences ,7. Clean energy ,Condensed Matter::Materials Science ,chemistry.chemical_compound ,General Materials Science ,Thermal stability ,Physical and Theoretical Chemistry ,media_common ,chemistry.chemical_classification ,Nanocomposite ,34 Chemical Sciences ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Tetracene ,chemistry ,Quantum dot ,Thiol ,0210 nano-technology ,Science, technology and society - Abstract
Triplet energy transfer between inorganic quantum dots (QDs) and organic materials plays a fundamental role in many optoelectronic applications based on these nanocomposites. Attaching organic molecules to the QD as transmitter ligands has been shown to facilitate transfer both to and from QDs. Here we show that the often disregarded thiol anchoring group can achieve quantitative triplet energy transfer yields in a PbS QD system with 6,11-bis[(triisopropylsilyl)ethynyl]tetracene-2-methylthiol (TET-SH) ligands. We demonstrate efficient triplet transfer in a singlet fission-based photon multiplication system with 5,12-bis[(triisopropylsilyl)ethynyl]tetracene generating triplets in solution that transfer to the PbS QDs via the thiol ligand TET-SH. Importantly, we demonstrate the increased thermal stability of the PbS/TET-SH system, compared to the traditional carboxylic acid counterpart, allowing for higher photoluminescence quantum yields.
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- 2020
39. Study protocol of the European Urban Burden of Disease Project: a health impact assessment study
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Mark J Nieuwenhuijsen, Jose Barrera-Gómez, Xavier Basagaña, Marta Cirach, Carolyn Daher, Maria Foraster Pulido, Tamara Iungman, Antonio Gasparrini, Gerard Hoek, Kees de Hoogh, Sasha Khomenko, Haneen Khreis, Audrey de Nazelle, Ana Ramos, David Rojas-Rueda, Evelise Pereira Barboza, Marko Tainio, Meelan Thondoo, Cathryn Tonne, James Woodcock, N Mueller, Apollo-University Of Cambridge Repository, Suomen ympäristökeskus, The Finnish Environment Institute, Nieuwenhuijsen, Mark J [0000-0001-9461-7981], Rojas-Rueda, David [0000-0001-5854-2484], Pereira Barboza, Evelise [0000-0002-2995-7418], Woodcock, James [0000-0003-4769-5375], and Apollo - University of Cambridge Repository
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vertailu ,kaupungit ,urban design ,urban planning ,methods ,diseases ,menetelmät ,Cost of Illness ,health effects ,Air Pollution ,liikenne ,terveysvaikutukset ,pollution ,Humans ,towns and cities ,Cities ,City Planning ,Eurooppa ,traffic ,Public health ,transport planning ,taudit ,Urban Health ,risk assessment ,health policy ,General Medicine ,kaupunkisuunnittelu ,riskinarviointi ,Europe ,liikennesuunnittelu ,comparison ,saastuminen ,Medicine ,epidemiology ,Health Impact Assessment - Abstract
Strengths and limitations of this study ► For the first time, the health impacts of current urban and transport planning practices and relationship with city characteristics in nearly 1000 European cities will be quantified. ► The linkages between urban and transport planning, environment, physical activity and health will be assessed in depth, and the health impacts of alternative urban and transport planning scenarios in cities will be modelled. ► We will employ a robust comparative risk assessment methodology (Urban and Transport Planning Health Impact Assessment) using state of the art input data on, for example, exposure response relationships to quantify related health impacts. ► Our analyses will be performed at high resolution (ie, grid-cell level with 250 m×250 m resolution), and the results will be estimated and compared within and between the cities, contributing to the design of evidence-based urban policies. ► The work is limited by the quantity, quality and comparability of some of the available city level exposure and health data, and the need to make assumptions where causal inference or specific guidelines is lacking. Introduction Cities have long been known to be society’s predominant engine of innovation and wealth creation, yet they are also hotspots of pollution and disease partly due to current urban and transport practices. The aim of the European Urban Burden of Disease project is to evaluate the health burden and its determinants related to current and future potential urban and transport planning practices and related exposures in European cities and make this evidence available for policy and decision making for healthy and sustainable futures. Methods and analysis Drawing on an established comparative risk assessment methodology (ie, Urban and Transport Planning Health Impact Assessment) tool), in nearly 1000 European cities we will (1) quantify the health impacts of current urban and transport planning related exposures (eg, air pollution, noise, excess heat, lack of green space) (2) and evaluate the relationship between current levels of exposure, health impacts and city characteristics (eg, size, density, design, mobility) (3) rank and compare the cities based on exposure levels and the health impacts, (4) in a number of selected cities assess in-depth the linkages between urban and transport planning, environment, physical activity and health, and model the health impacts of alternative and realistic urban and transport planning scenarios, and, finally, (5) construct a healthy city index and set up an effective knowledge translation hub to generate impact in society and policy. Ethics and dissemination All data to be used in the project are publicly available data and do not need ethics approval. We will request consent for personal data on opinions and views and create data agreements for those providing information on current and future urban and transport planning scenarios. For dissemination and to generate impact, we will create a knowledge translation hub with information tailored to various stakeholders.
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- 2022
40. Evolution of a Relativistic Outflow and X-ray Corona in the Extreme Changing-Look AGN 1ES 1927+654
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Megan Masterson, Erin Kara, Claudio Ricci, Javier A. García, Andrew C. Fabian, Ciro Pinto, Peter Kosec, Ronald A. Remillard, Michael Loewenstein, Benny Trakhtenbrot, Iair Arcavi, Apollo-University Of Cambridge Repository, Masterson, Megan [0000-0003-4127-0739], Kara, Erin [0000-0003-0172-0854], Ricci, Claudio [0000-0001-5231-2645], García, Javier A [0000-0003-3828-2448], Fabian, Andrew C [0000-0002-9378-4072], Pinto, Ciro [0000-0003-2532-7379], Kosec, Peter [0000-0003-4511-8427], Remillard, Ronald A [0000-0003-4815-0481], Loewenstein, Michael [0000-0002-1661-4029], Trakhtenbrot, Benny [0000-0002-3683-7297], Arcavi, Iair [0000-0001-7090-4898], and Apollo - University of Cambridge Repository
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High Energy Astrophysical Phenomena (astro-ph.HE) ,Space and Planetary Science ,5101 Astronomical Sciences ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics - High Energy Astrophysical Phenomena ,51 Physical Sciences ,High-Energy Phenomena and Fundamental Physics ,Astrophysics::Galaxy Astrophysics - Abstract
1ES 1927+654 is a paradigm-defying AGN and one of the most peculiar X-ray nuclear transients. In early 2018, this well-known AGN underwent a changing-look event, in which broad optical emission lines appeared and the optical flux increased. Yet, by July 2018, the X-ray flux had dropped by over two orders of magnitude, indicating a dramatic change to the inner accretion flow. With three years of observations with NICER, XMM-Newton, and NuSTAR, we present the X-ray evolution of 1ES 1927+654, which can be broken into three phases-(1) an early super-Eddington phase with rapid variability in X-ray luminosity and spectral parameters, (2) a stable super-Eddington phase at the peak X-ray luminosity, and (3) a steady decline back to the pre-outburst luminosity and spectral parameters. For the first time, we witnessed the formation of the X-ray corona, as the X-ray spectrum transitioned from thermally-dominated to primarily Comptonized. We also track the evolution of the prominent, broad 1 keV feature in the early X-ray spectra and show that this feature can be modeled with blueshifted reflection (z = -0.33) from a single-temperature blackbody irradiating spectrum using xillverTDE, a new flavor of the xillver models. Thus, we propose that the 1 keV feature could arise from reflected emission off the base of an optically thick outflow from a geometrically thick, super-Eddington inner accretion flow, connecting the inner accretion flow with outflows launched during extreme accretion events (e.g. tidal disruption events). Lastly, we compare 1ES 1927+654 to other nuclear transients and discuss applications of xillverTDE to super-Eddington accretors., Comment: 25 pages, 10 figures, accepted for publication in ApJ
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- 2022
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41. Digital transformation, for better or worse: a critical multi‐level research agenda
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Justyna Dąbrowska, Argyro Almpanopoulou, Alexander Brem, Henry Chesbrough, Valentina Cucino, Alberto Di Minin, Ferran Giones, Henri Hakala, Cristina Marullo, Anne‐Laure Mention, Letizia Mortara, Sladjana Nørskov, Petra A. Nylund, Calogero Maria Oddo, Agnieszka Radziwon, Paavo Ritala, Apollo-University Of Cambridge Repository, Dąbrowska, J [0000-0002-4578-2945], Almpanopoulou, A [0000-0002-5362-842X], Brem, A [0000-0002-6901-7498], Cucino, V [0000-0002-4910-5861], Di Minin, A [0000-0002-4904-1335], Giones, F [0000-0002-1927-6918], Hakala, H [0000-0002-3612-7391], Marullo, C [0000-0002-6133-9214], Mention, AL [0000-0001-9558-8799], Mortara, L [0000-0003-0461-5339], Nørskov, S [0000-0003-2337-5019], Nylund, PA [0000-0002-7819-3565], Oddo, CM [0000-0002-1489-5701], Radziwon, A [0000-0001-8491-6590], Ritala, P [0000-0002-8525-4610], Apollo - University of Cambridge Repository, Tampere University, and Industrial Engineering and Management
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digital technologies ,organizational change ,socioeconomic change ,Strategy and Management ,transformation ,digitalization of innovation ,512 Business and management ,3503 Business Systems In Context ,digitalization ,General Business, Management and Accounting ,Research Papers ,35 Commerce, Management, Tourism and Services ,open innovation ,platforms ,Management of Technology and Innovation ,digital transformation ,business models ,Business and International Management ,organizational systems ,ecosystems ,Research Paper - Abstract
For better or worse, digital technologies are reshaping everything we know, from customer behaviour and expectations to organizational and manufacturing systems, business models, markets, and ultimately society as a whole. To understand this overarching transformation, this paper extends the previous literature, which has focused mostly on the organizational level, by developing a multi-level research agenda for digital transformation (DT). In this regard, we propose an extended definition of DT as a socioeconomic change across individuals, organizations, ecosystems, and societies that is shaped by the adoption and utilization of digital technologies. We propose four lenses to interpret the DT phenomenon: individuals (utilizing and adopting digital technologies), organizations (strategizing and coordinating both internal and external transformation), ecosystems (harnessing digital technologies in governance and co-producing value propositions), and geopolitical frameworks (regulating the environments in which individuals and organizations are embedded). Based on these lenses, we build a multi-level research agenda at the intersection between the bright and dark sides of DT and propose the PIAI framework, which captures a process of perception, interpretation, and action that ultimately leads to the possible impact of intended and unintended consequences for the socioeconomic infrastructure. The PIAI framework identifies a research agenda consisting of a non-exhaustive list of topics that can assist researchers to deepen their understanding of the DT phenomenon and provide guidance to managers and policymakers when making strategic decisions that seek to shape and guide the DT.
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- 2022
42. Neanderthals on the Lower Danube: Middle Palaeolithic evidence in the Danube Gorges of the Balkans
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Kristine Korzow Richter, Vesna Dimitrijević, Rachel J A Hopkins, Emanuela Cristiani, Dusan Boric, Dustin White, Alana Masciana, Ana B. Marín-Arroyo, Karol Wehr, Jennifer R. Jones, Jelena Ćalić, Kevin T. Uno, Giuseppina Mutri, Dragana Antonović, Jean-Luc Schwenninger, Christine Lane, Katarina Gerometta, Rhiannon E. Stevens, C. French, Universidad de Cantabria, Borić, Dušan [0000-0003-0166-627X], Cristiani, Emanuela [0000-0002-2748-9171], Hopkins, Rachel [0000-0002-6254-7955], Gerometta, Katarina [0000-0002-9601-4911], French, Charly AI [0000-0001-7967-3248], Mutri, Giuseppina [0000-0002-4069-0507], Ćalić, Jelena [0000-0002-7271-5561], Dimitrijević, Vesna [0000-0001-8121-5457], Marín-Arroyo, Ana B [0000-0003-3353-5581], Jones, Jennifer R [0000-0002-9247-7994], Stevens, Rhiannon [0000-0002-6140-4549], Masciana, Alana [0000-0002-0805-9299], Uno, Kevin [0000-0001-6882-0900], Richter, Kristine Korzow [0000-0003-3591-6900], Antonović, Dragana [0000-0002-6534-1258], Lane, Christine [0000-0001-9206-3903], Apollo - University of Cambridge Repository, French, Charly A. I. [0000-0001-7967-3248], Marín‐Arroyo, Ana B. [0000-0003-3353-5581], Jones, Jennifer R. [0000-0002-9247-7994], and Apollo-University Of Cambridge Repository
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Special Issue Articles ,010506 paleontology ,OSL dating ,V490 ,cryptotephra ,Danube Gorges ,Palaeolithic ,radiocarbon dating ,ZooMS ,Structural basin ,01 natural sciences ,law.invention ,Arts and Humanities (miscellaneous) ,Cave ,law ,Earth and Planetary Sciences (miscellaneous) ,V460 ,0601 history and archaeology ,Radiocarbon dating ,V400 ,Zooarchaeology ,0105 earth and related environmental sciences ,geography ,geography.geographical_feature_category ,060102 archaeology ,Special Issue Article ,Paleontology ,Excavation ,06 humanities and the arts ,Karst ,Archaeology ,Radiometric dating ,Geology ,Accelerator mass spectrometry - Abstract
Funder: NOMIS Stiftung; Id: http://dx.doi.org/10.13039/501100008483, The article presents evidence about the Middle Palaeolithic and Middle to Upper Palaeolithic transition interval in the karst area of the Danube Gorges in the Lower Danube Basin. We review the extant data and present new evidence from two recently investigated sites found on the Serbian side of the Danube River – Tabula Traiana and Dubočka‐Kozja caves. The two sites have yielded layers dating to both the Middle and Upper Palaeolithic and have been investigated by the application of modern standards of excavation and recovery along with a suite of state‐of‐the‐art analytical procedures. The presentation focuses on micromorphological analyses of the caves’ sediments, characterisation of cryptotephra, a suite of new radiometric dates (accelerator mass spectrometry and optically stimulated luminescence) as well as proteomics (zooarchaeology by mass spectrometry) and stable isotope data in discerning patterns of human occupation of these locales over the long term.
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- 2022
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43. Reduced Barrier for Ion Migration in Mixed-Halide Perovskites
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McGovern, Lucie, Grimaldi, Gianluca, Futscher, Moritz H., Hutter, Eline M., Muscarella, Loreta A., Schmidt, Moritz C., Ehrler, Bruno, Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, McGovern, Lucie [0000-0001-7263-5249], Grimaldi, Gianluca [0000-0002-2626-9118], Futscher, Moritz H [0000-0001-8451-5009], Hutter, Eline M [0000-0002-5537-6545], Muscarella, Loreta A [0000-0002-0559-4085], Ehrler, Bruno [0000-0002-5307-3241], Apollo - University of Cambridge Repository, and Apollo-University Of Cambridge Repository
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ion migration ,Letter ,Energy Engineering and Power Technology ,02 engineering and technology ,mixed halide ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,7. Clean energy ,0104 chemical sciences ,methylammonium ,activation energy ,transient ion drift ,Electrochemistry ,Materials Chemistry ,halide ,Chemical Engineering (miscellaneous) ,Electrical and Electronic Engineering ,0210 nano-technology ,perovskite ,phase segregation - Abstract
Halide alloying in metal halide perovskites is a useful tool for optoelectronic applications requiring a specific bandgap. However, mixed-halide perovskites show ion migration in the perovskite layer, leading to phase segregation and reducing the long-term stability of the devices. Here, we study the ion migration process in methylammonium-based mixed-halide perovskites with varying ratios of bromide to iodide. We find that the mixed-halide perovskites show two separate halide migration processes, in contrast to pure-phase perovskites, which show only a unique halide migration component. Compared to pure-halide perovskites, these processes have lower activation energies, facilitating ion migration in mixed versus pure-phase perovskites, and have a higher density of mobile ions. Under illumination, we find that the concentration of mobile halide ions is further increased and notice the emergence of a migration process involving methylammonium cations. Quantifying the ion migration processes in mixed-halide perovskites shines light on the key parameters allowing the design of bandgap-tunable perovskite solar cells with long-term stability.
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- 2021
44. Mismatched Decoding Reliability Function at Zero Rate
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Marco Dalai, Albert Guillen i Fabregas, Marco Bondaschi, Apollo-University Of Cambridge Repository, Bondaschi, M [0000-0002-4158-2487], Fabregas, AGI [0000-0003-2795-1124], Dalai, M [0000-0003-2132-7072], and Apollo - University of Cambridge Repository
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FOS: Computer and information sciences ,Reliability (computer networking) ,Computer Science - Information Theory ,Decoding ,02 engineering and technology ,Library and Information Sciences ,information rates ,Upper and lower bounds ,Codes ,0202 electrical engineering, electronic engineering, information engineering ,exponents ,Random variables ,Mathematics ,Computer Science::Information Theory ,Discrete mathematics ,Measurement ,capacity ,Information Theory (cs.IT) ,Zero (complex analysis) ,Error exponents ,020206 networking & telecommunications ,Function (mathematics) ,Reliability ,Symmetry (physics) ,Computer Science Applications ,Capacity planning ,Mismatched decoding ,Metric (mathematics) ,mismatched decoding ,Exponent ,Decoding methods ,Upper bound ,Information Systems - Abstract
We derive an upper bound on the reliability function of mismatched decoding for zero-rate codes. The bound is based on a result by Koml ́os that shows the existence of a subcode with certain symmetry properties. The bound is shown to coincide with the expurgated exponent at rate zero for a broad family of channel-decoding metric pairs.
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- 2021
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45. Improving the stability of plasmonic magnesium nanoparticles in aqueous media
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Jérémie Asselin, Elizabeth R. Hopper, Emilie Ringe, Apollo-University Of Cambridge Repository, Ringe, Emilie [0000-0003-3743-9204], and Apollo - University of Cambridge Repository
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FOS: Nanotechnology ,Materials science ,Aqueous medium ,Magnesium ,chemistry.chemical_element ,Nanoparticle ,Bioengineering ,02 engineering and technology ,sub-03 ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Chemistry ,Chemical engineering ,chemistry ,Nanotechnology ,General Materials Science ,4018 Nanotechnology ,0210 nano-technology ,Plasmon ,40 Engineering - Abstract
This work describes two different core–shell architectures based on Mg nanoparticles (NPs) synthesised in order to improve Mg's stability in aqueous solutions. The shell thickness in Mg–polydopamine NPs can be modulated from 5 to >50 nm by ending the polymerization at different times; the resulting structures stabilize the metallic, plasmonic core in water for well over an hour. Mg–silica NPs with shells ranging from 5 to 30 nm can also be prepared via a modified Stöber procedure and they retain optical properties in 5% water-in-isopropanol solutions. These new architectures allow Mg nanoplasmonics to be investigated as an alternative to Ag and Au in a broader range of experimental conditions for a rich variety of applications., Plasmonic Mg nanoparticles can be stabilised up to a few hours in aqueous suspensions by protecting them inside core–shell architectures, which are prepared by condensation of either polydopamine or sol–gel silica.
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- 2021
46. High-throughput total RNA sequencing in single cells using VASA-seq
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Fredrik Salmen, Joachim De Jonghe, Tomasz S. Kaminski, Anna Alemany, Guillermo E. Parada, Joe Verity-Legg, Ayaka Yanagida, Timo N. Kohler, Nicholas Battich, Floris van den Brekel, Anna L. Ellermann, Alfonso Martinez Arias, Jennifer Nichols, Martin Hemberg, Florian Hollfelder, Alexander van Oudenaarden, De Jonghe, Joachim [0000-0003-0584-8265], Kaminski, Tomasz S [0000-0001-5124-4548], Parada, Guillermo E [0000-0003-1018-9882], Kohler, Timo N [0000-0003-1949-0655], Ellermann, Anna L [0000-0002-3713-2870], Hemberg, Martin [0000-0001-8895-5239], Hollfelder, Florian [0000-0002-1367-6312], van Oudenaarden, Alexander [0000-0002-9442-3551], Apollo - University of Cambridge Repository, Apollo-University Of Cambridge Repository, and Hubrecht Institute for Developmental Biology and Stem Cell Research
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Mammals ,RNA splicing ,Sequence Analysis, RNA ,Gene Expression Profiling ,Gastrulation ,Biomedical Engineering ,High-Throughput Nucleotide Sequencing ,Bioengineering ,Applied Microbiology and Biotechnology ,Non-coding RNAs ,Mice ,Alternative Splicing ,Databases ,Molecular Medicine ,Animals ,RNA ,Transcriptome ,Transcriptomics ,Biotechnology - Abstract
Data de publicació electrònica: 27-06-2022 Most methods for single-cell transcriptome sequencing amplify the termini of polyadenylated transcripts, capturing only a small fraction of the total cellular transcriptome. This precludes the detection of many long non-coding, short non-coding and non-polyadenylated protein-coding transcripts and hinders alternative splicing analysis. We, therefore, developed VASA-seq to detect the total transcriptome in single cells, which is enabled by fragmenting and tailing all RNA molecules subsequent to cell lysis. The method is compatible with both plate-based formats and droplet microfluidics. We applied VASA-seq to more than 30,000 single cells in the developing mouse embryo during gastrulation and early organogenesis. Analyzing the dynamics of the total single-cell transcriptome, we discovered cell type markers, many based on non-coding RNA, and performed in vivo cell cycle analysis via detection of non-polyadenylated histone genes. RNA velocity characterization was improved, accurately retracing blood maturation trajectories. Moreover, our VASA-seq data provide a comprehensive analysis of alternative splicing during mammalian development, which highlighted substantial rearrangements during blood development and heart morphogenesis. This work was supported by a European Research Council (ERC) Advanced Grant (ERC-AdG 742225-IntScOmics), a Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO) TOP award (NWO-CW 714.016.001) and the Wellcome Trust (WT108438/C/15/Z). This work is part of the Oncode Institute, which is partly financed by the Dutch Cancer Society. J.D.J. received scholarship support from the Biotechnology and Biological Sciences Research Council (BBSRC), T.N.K. from AstraZeneca, A.L.E. from the Cambridge Trusts and the EU H2020 Marie Curie ITN MMBio and T.S.K. from an EU H2020 Marie Skłodowska-Curie Actions Individual Fellowship (MSCA-IF 750772). F.H. is an H2020 ERC Advanced Investigator (69566). M.H. was supported by a core grant from the Wellcome Trust and by funding from the Evergrande Center for Immunologic Diseases. J.N. was funded by the Wellcome Trust (03151/Z/16/Z). For the purpose of open access, the author has applied a CC BY public copyright license to any Author Accepted Manuscript version arising from this submission. A.Y. was funded by the BBSRC (RG83885), and the mice used in the study are associated with the Wellcome Trust Strategic Grant (105031). Parts of the illustrations were designed using BioRender.
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- 2021
47. Spontaneous exciton dissociation enables spin state interconversion in delayed fluorescence organic semiconductors
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Bluebell H. Drummond, Weimin Chen, Claire Tonnelé, David Casanova, Neil C. Greenham, Richard H. Friend, David Beljonne, Yuttapoom Puttisong, Patrick J. Conaghan, Lin-Song Cui, Yoann Olivier, Gaetano Ricci, Emrys W. Evans, Frédéric Castet, Manon Catherin, Alexander J. Gillett, Giacomo Londi, Frédéric Fages, Elena Zaborova, Darcy M. L. Unson, Gillett, Alexander J [0000-0001-7572-7333], Tonnelé, Claire [0000-0003-0791-8239], Londi, Giacomo [0000-0001-7777-9161], Casanova, David [0000-0002-8893-7089], Castet, Frédéric [0000-0002-6622-2402], Chen, Weimin M [0000-0002-6405-9509], Evans, Emrys W [0000-0002-9092-3938], Drummond, Bluebell H [0000-0001-5940-8631], Greenham, Neil C [0000-0002-2155-2432], Puttisong, Yuttapoom [0000-0002-9690-6231], Fages, Frédéric [0000-0003-2013-0710], Beljonne, David [0000-0001-5082-9990], Friend, Richard H [0000-0001-6565-6308], Apollo - University of Cambridge Repository, Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Institut des Sciences Moléculaires (ISM), Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1 (UB)-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Apollo-University Of Cambridge Repository, Gillett, Alexander J. [0000-0001-7572-7333], Chen, Weimin M. [0000-0002-6405-9509], Evans, Emrys W. [0000-0002-9092-3938], Drummond, Bluebell H. [0000-0001-5940-8631], Greenham, Neil C. [0000-0002-2155-2432], and Friend, Richard H. [0000-0001-6565-6308]
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120 ,Materials science ,Spin states ,Band gap ,Science ,Atom and Molecular Physics and Optics ,639/624/1020/1091 ,General Physics and Astronomy ,FOS: Physical sciences ,02 engineering and technology ,Applied Physics (physics.app-ph) ,010402 general chemistry ,01 natural sciences ,Molecular physics ,General Biochemistry, Genetics and Molecular Biology ,Radiative transfer ,Organic LEDs ,639/301/1019/1020/1091 ,140/125 ,Hyperfine structure ,Condensed Matter - Materials Science ,Multidisciplinary ,132 ,article ,Materials Science (cond-mat.mtrl-sci) ,General Chemistry ,Physics - Applied Physics ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,cond-mat.mtrl-sci ,0104 chemical sciences ,Organic semiconductor ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,Microsecond ,Intersystem crossing ,Intramolecular force ,Atom- och molekylfysik och optik ,0210 nano-technology ,physics.app-ph - Abstract
Engineering a low singlet-triplet energy gap (ΔEST) is necessary for efficient reverse intersystem crossing (rISC) in delayed fluorescence (DF) organic semiconductors but results in a small radiative rate that limits performance in LEDs. Here, we study a model DF material, BF2, that exhibits a strong optical absorption (absorption coefficient = 3.8 × 105 cm−1) and a relatively large ΔEST of 0.2 eV. In isolated BF2 molecules, intramolecular rISC is slow (delayed lifetime = 260 μs), but in aggregated films, BF2 generates intermolecular charge transfer (inter-CT) states on picosecond timescales. In contrast to the microsecond intramolecular rISC that is promoted by spin-orbit interactions in most isolated DF molecules, photoluminescence-detected magnetic resonance shows that these inter-CT states undergo rISC mediated by hyperfine interactions on a ~24 ns timescale and have an average electron-hole separation of ≥1.5 nm. Transfer back to the emissive singlet exciton then enables efficient DF and LED operation. Thus, access to these inter-CT states, which is possible even at low BF2 doping concentrations of 4 wt%, resolves the conflicting requirements of fast radiative emission and low ΔEST in organic DF emitters., A low singlet-triplet energy gap, necessary for delayed fluorescence organic semiconductors, results in a small radiative rate that limits performance in OLEDs. Here, the authors show that it is possible to reconcile these conflicting requirements in materials that can access both high oscillator strength intramolecular excitations and intermolecular charge transfer states.
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- 2021
48. Genotype data not consistent with clonal transmission of sea turtle fibropapillomatosis or goldfish schwannoma
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Kelsey Yetsko, Elizabeth P. Murchison, Jessica A. Farrell, Carmelo Iaria, Gabriele Marino, David J. Duffy, Máire Ní Leathlobhair, Apollo-University Of Cambridge Repository, Ní Leathlobhair, Máire [0000-0002-8523-4935], Iaria, Carmelo [0000-0001-7930-8881], Duffy, David J [0000-0002-6075-8855], Murchison, Elizabeth P [0000-0001-7462-8907], and Apollo - University of Cambridge Repository
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0106 biological sciences ,Fibropapillomatosis ,viruses ,Transmissible Cancer ,Medicine (miscellaneous) ,Disease ,Schwannoma ,010603 evolutionary biology ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,Genotype ,medicine ,Allele ,Sea Turtle Fibropapillomatosis ,030304 developmental biology ,Genetics ,0303 health sciences ,biology ,Transmission (medicine) ,Articles ,biochemical phenomena, metabolism, and nutrition ,medicine.disease ,biology.organism_classification ,3. Good health ,Research Note ,Wildlife Cancer ,Sea turtle ,sea turtle fibropapillomatosis, fibropapillomatosis, goldfish schwannoma, transmissible cancer, wildlife cancer ,Cancer cell ,Goldfish Schwannoma - Abstract
Recent discoveries of transmissible cancers in multiple bivalve species suggest that direct transmission of cancer cells within species may be more common than previously thought, particularly in aquatic environments. Fibropapillomatosis occurs with high prevalence in green sea turtles (Chelonia mydas) and the geographic range of disease has increased since fibropapillomatosis was first reported in this species. Widespread incidence of schwannomas, benign tumours of Schwann cell origin, reported in aquarium-bred goldfish(Carassius auratus),suggest an infectious aetiology. We investigated the hypothesis that cancers in these species arise by clonal transmission of cancer cells. Through analysis of polymorphic microsatellite alleles, we demonstrate concordance of host and tumour genotypes in diseased animals. These results imply that the tumours examined arose from independent oncogenic transformation of host tissue and were not clonally transmitted. Further, failure to experimentally transmit goldfish schwannoma via water exposure or inoculation suggest that this disease is unlikely to have an infectious aetiology.
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- 2021
49. The Impact of the HydroxyMethylCytosine epigenetic signature on DNA structure and function
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Chiara Lara Castellazzi, Montserrat Terrazas, Pablo D. Dans, Guillem Portella, Federica Battistini, Isabelle Brun-Heath, Carlos González, Núria Villegas, Modesto Orozco, Mireia Labrador, Ministerio de Ciencia e Innovación (España), Generalitat de Catalunya, Instituto de Salud Carlos III, Instituto Nacional de Bioinformática (España), European Commission, Ministerio de Economía y Competitividad (España), Agencia Nacional de Investigación e Innovación (Uruguay), Apollo-University Of Cambridge Repository, Battistini, Federica [0000-0002-7544-0938], Dans, Pablo D [0000-0002-5927-372X], Terrazas, Montserrat [0000-0001-8614-5777], Labrador, Mireia [0000-0002-7105-1054], Villegas, Núria [0000-0001-9323-0697], Brun-Heath, Isabelle [0000-0002-5828-0020], González, Carlos [0000-0001-8796-1282], and Apollo - University of Cambridge Repository
- Subjects
Magnetic Resonance Spectroscopy ,ADN ,Biochemistry ,Stiffness ,Epigenesis, Genetic ,chemistry.chemical_compound ,0302 clinical medicine ,Biochemical Simulations ,Biology (General) ,Translocation (Genetics) ,0303 health sciences ,Ecology ,Translocació (Genètica) ,Chemistry ,Nucleotides ,Organic Compounds ,Physics ,Nuclear magnetic resonance spectroscopy ,Chromatin ,Nucleosomes ,Circular DNA ,Nucleic acids ,Physical sciences ,Computational Theory and Mathematics ,Modeling and Simulation ,DNA methylation ,5-Methylcytosine ,Epigenetics ,DNA modification ,Cytosine ,Chromatin modification ,Chromosome biology ,Research Article ,Cell biology ,QH301-705.5 ,Forms of DNA ,Materials Science ,Material Properties ,FOS: Physical sciences ,Molecular Dynamics Simulation ,Models, Biological ,Biophysical Phenomena ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,Genetics ,Nucleosome ,Mechanical Properties ,Humans ,Molecular Biology ,Psychological repression ,Ecology, Evolution, Behavior and Systematics ,030304 developmental biology ,Binding Sites ,Biology and life sciences ,Organic Chemistry ,Chemical Compounds ,Computational Biology ,DNA ,DNA Methylation ,Epigenètica ,Physical Properties ,Pyrimidines ,Biophysics ,Nucleic Acid Conformation ,Gene expression ,030217 neurology & neurosurgery - Abstract
Funder: Government of Spain, Funder: Instituci�� Catalana de Recerca i Estudis Avancats, Funder: Programa de Desarrollo de las Ciencias Basicas, Funder: Sistema Nacional de Investigadores, Agencia Nacional de Investigaci��n e Innovaci��n, Uruguay, We present a comprehensive, experimental and theoretical study of the impact of 5-hydroxymethylation of DNA cytosine. Using molecular dynamics, biophysical experiments and NMR spectroscopy, we found that Ten-Eleven translocation (TET) dioxygenases generate an epigenetic variant with structural and physical properties similar to those of 5-methylcytosine. Experiments and simulations demonstrate that 5-methylcytosine (mC) and 5-hydroxymethylcytosine (hmC) generally lead to stiffer DNA than normal cytosine, with poorer circularization efficiencies and lower ability to form nucleosomes. In particular, we can rule out the hypothesis that hydroxymethylation reverts to unmodified cytosine physical properties, as hmC is even more rigid than mC. Thus, we do not expect dramatic changes in the chromatin structure induced by differences in physical properties between d(mCpG) and d(hmCpG). Conversely, our simulations suggest that methylated-DNA binding domains (MBDs), associated with repression activities, are sensitive to the substitution d(mCpG) ��� d(hmCpG), while MBD3 which has a dual activation/repression activity is not sensitive to the d(mCpG) d(hmCpG) change. Overall, while gene activity changes due to cytosine methylation are the result of the combination of stiffness-related chromatin reorganization and MBD binding, those associated to 5-hydroxylation of methylcytosine could be explained by a change in the balance of repression/activation pathways related to differential MBD binding.
- Published
- 2021
50. Sound Authorities: Scientific and Musical Knowledge in Nineteenth-Century Britain
- Author
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Edward J. Gillin, Apollo-University Of Cambridge Repository, and Apollo - University of Cambridge Repository
- Abstract
In Sound Authorities, Edward J. Gillin shows how experiences of music and sound played a crucial role in nineteenth-century scientific inquiry in Britain.
- Published
- 2021
- Full Text
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