Search

Background: Meeting the global demand for grain is becoming increasingly difficult due to numerous factors including climate variability, urbanization, increasingly frequent extreme weather events and drought. Stalk lodging destroys between 5%-25% of grain crops annually. Developing crop varieties with improved lodging resistance will reduce the frequency and impact of stalk lodging and consequently reduce the yield gap. Field-phenotyping equipment is critical to develop lodging resistant crop varieties, but the effectiveness of current equipment is hindered by measurement error. Relatively little research has been done to identify and rectify sources of measurement error in biomechanical phenotyping platforms. This study specifically investigated sources of error in bending stiffness and bending strength measurements which are often acquired using field-phenotyping devices. Three specific sources of error in bending stiffness and bending strength measurements were evaluated: horizontal device placement, vertical device placement and incorrect recordings of load cell height. Results: Incorrect load cell heights introduced errors as large as 130% in bending stiffness and 50% in bending strength. Results indicated that errors on the order of 15%-25% in bending stiffness and 1–10% in bending strength are common in field-based measurements. Improving operating procedures and protocols can mitigate this error. Such improvements include emphasizing attention to detail while conducting tests and improving the design of phenotyping equipment. Conclusion: Reducing measurement error in field-phenotyping equipment is crucial for advancing the development of improved, lodging-resistant crop varieties. The study found that incorrect load cell height entry and incorrect device placement both significantly contributed to measurement error in bending stiffness and bending strength measurements. These findings have important implications for reducing the yield gap in staple crops and meeting the global demand for grain.

Combustion synthesis in uranyl nitrate-acetylacetone-2-methoxyethanol solutions was used to deposit thin UO2 films on aluminum substrates to investigate the irradiation-induced restructuring processes. Thermal analysis revealed that the combustion reactions in these solutions are initiated at ∼160 °C. The heat released during the process and the subsequent brief annealing at 400 °C allow the deposition of polycrystalline films with 5-10 nm UO2 grains. The use of multiple deposition cycles enables tuning of the film thicknesses in the 35-260 nm range. Irradiation with Ar2+ ions (1.7 MeV energy and a fluence of up to 1 × 1017 ions/cm2) is utilized to generate a uniform distribution of atomic displacements within the films. X-ray fluorescence (XRF) and alpha-particle emission spectroscopy showed that the films were stable under irradiation and did not undergo sputtering degradation. X-ray photoelectron spectroscopy (XPS) showed that the stoichiometry and uranium ionic concentrations remain stable during irradiation. The high-resolution electron microscopy imaging and electron diffraction analysis demonstrated that at the early stages of irradiation (below 1 × 1016 ion/cm2) UO2 films show complete amorphization and beam-induced densification (sintering), resulting in a pore-free disordered film. Prolonged irradiation (5 × 1016 ion/cm2) is shown to trigger a crystallization process at the surface of the films that moves toward the UO2/Al interface, converting the entire amorphous material into a highly crystalline film. This work reports on an entirely different radiation-induced restructuring of the nanoscale UO2 compared to the coarse-grained counterpart. The preparation of thin UO2 films deposited on Al substrates fills an area of national need within the stockpile stewardship program of the National Nuclear Security Administration and fundamental research with actinides. The method reported in this work produces pure, robust, and uniform thin-film actinide targets for nuclear science measurements.

The Structural Maintenance of Chromosomes (SMC) complexes cohesin and condensin establish the 3D organization of mitotic chromosomes1–3. Cohesin is essential to maintain sister chromatid pairing until anaphase onset4, while condensin is important for mitotic centromere structure and elastic resistance to spindle forces5–8. Both complexes are also important to form productive kinetochore-spindle attachments6, 8, 9. How condensin and cohesin work together to shape the mitotic centromere to ensure faithful chromosome segregation remains unclear. Here we show by super-resolution imaging, Capture-C analysis and polymer modeling that vertebrate centromeres are partitioned into two distinct condensin-dependent subdomains during mitosis. This bipartite sub-structure is found in human, mouse and chicken centromeres and also in human neocentromeres devoid of satellite repeats, and is therefore a fundamental feature of vertebrate centromere identity. Super-resolution imaging reveals that bipartite centromeres assemble bipartite kinetochores with each subdomain capable of binding a distinct microtubule bundle. Cohesin helps to link the centromere subdomains, limiting their separation in response to mitotic spindle forces. In its absence, separated bipartite kinetochores frequently engage in merotelic spindle attachments. Consistently, uncoupling of centromere subdomains is a common feature of lagging chromosomes in cancer cells. The two-domain structure of vertebrate regional centromeres described here incorporates architectural roles for both condensin and cohesin and may have implications for avoiding chromosomal instability in cancer cells.

We report on the reversible, electrochemical (de)fluorination of the defect fluoride pyrochlore CsMnFeF6 at room temperature using a liquid electrolyte. CsMnFeF6 was synthesized via three different methods (hydrothermal, ceramic, and mechanochemical), each of which yield products of varying particle size and phase purity. Using galvanostatic cycling, we found that after three oxidative/ reductive cycles, approximately one fluoride ion can be reversibly inserted and removed from mechanochemically synthesized CsMnFeF6 for multiple cycles. Ex-situ X-ray absorption spectroscopy confirmed that both the Mn2+ and Fe3+ in this composition are redox active during cycling. Electrochemical impedance spectroscopy and ex-situ synchrotron powder diffraction were utilized to investigate the delayed onset of significant fluoride (de)insertion. We observed decreased impedance after one full cycle and subtle expansion and contraction of the CsMnFeF6 cubic lattice on oxidation (insertion) and reduction (removal), respectively, over the first two cycles. Our results suggest the formation of fluoride vacancies in early cycles generates mixed-valent Fe that enhances the conductivity and improves the reversibility in later cycles.

Off-Site Modular Construction (OSMC) research has been a growing research area over the past two decades because of low productivity in construction. Tools are superior in factories and productivity is much higher compared to a stick built site. This has spawned the development small, factory built, rapidly deployable and flexible process plants to take advantage of the gains in OSMC productivity. Chemical process plant research is studying fast, automated design and configuration. In this paper, a literature review was performed on modular factory manufactured process plants. The literature review found that moving to small scale OSMC plant systems could enable cost and schedule savings and months of design time compared to the previous on-site assembly design. It was also found that while automation has been applied in earlier stages of the plant design process, a layout optimisation methodology has not been applied to small OSMC process plants. The paper then proposes to utilise a mathematical layout optimisation model to help design and construct modular process plants and considers how this may fit into the process plant design process, as well as considering the transport requirements for modules.

Combustion synthesis in uranyl nitrate-acetylacetone-2-methoxyethanol solutions was used to deposit thin UO

A plethora of biological processes like gene transcription, DNA replication, DNA recombination, and chromosome segregation are mediated through protein–DNA interactions. A powerful method for investigating proteins within a native chromatin environment in the cell is chromatin immunoprecipitation (ChIP). Combined with the recent technological advancement in next generation sequencing, the ChIP assay can map the exact binding sites of a protein of interest across the entire genome. Here we describe a-step-by step protocol for ChIP followed by library preparation for ChIP-seq from yeast cells.

A plethora of biological processes like gene transcription, DNA replication, DNA recombination, and chromosome segregation are mediated through protein–DNA interactions. A powerful method for investigating proteins within a native chromatin environment in the cell is chromatin immunoprecipitation (ChIP). Combined with the recent technological advancement in next generation sequencing, the ChIP assay can map the exact binding sites of a protein of interest across the entire genome. Here we describe a-step-by step protocol for ChIP followed by library preparation for ChIP-seq from yeast cells.

A plethora of biological processes like gene transcription, DNA replication, DNA recombination, and chromosome segregation are mediated through protein–DNA interactions. A powerful method for investigating proteins within a native chromatin environment in the cell is chromatin immunoprecipitation (ChIP). Combined with the recent technological advancement in next generation sequencing, the ChIP assay can map the exact binding sites of a protein of interest across the entire genome. Here we describe a-step-by step protocol for ChIP followed by library preparation for ChIP-seq from yeast cells.

A plethora of biological processes like gene transcription, DNA replication, DNA recombination, and chromosome segregation are mediated through protein–DNA interactions. A powerful method for investigating proteins within a native chromatin environment in the cell is chromatin immunoprecipitation (ChIP). Combined with the recent technological advancement in next generation sequencing, the ChIP assay can map the exact binding sites of a protein of interest across the entire genome. Here we describe a-step-by step protocol for ChIP followed by library preparation for ChIP-seq from yeast cells.

A plethora of biological processes like gene transcription, DNA replication, DNA recombination, and chromosome segregation are mediated through protein–DNA interactions. A powerful method for investigating proteins within a native chromatin environment in the cell is chromatin immunoprecipitation (ChIP). Combined with the recent technological advancement in next generation sequencing, the ChIP assay can map the exact binding sites of a protein of interest across the entire genome. Here we describe a-step-by step protocol for ChIP followed by library preparation for ChIP-seq from yeast cells.

A plethora of biological processes like gene transcription, DNA replication, DNA recombination, and chromosome segregation are mediated through protein–DNA interactions. A powerful method for investigating proteins within a native chromatin environment in the cell is chromatin immunoprecipitation (ChIP). Combined with the recent technological advancement in next generation sequencing, the ChIP assay can map the exact binding sites of a protein of interest across the entire genome. Here we describe a-step-by step protocol for ChIP followed by library preparation for ChIP-seq from yeast cells.

A plethora of biological processes like gene transcription, DNA replication, DNA recombination, and chromosome segregation are mediated through protein–DNA interactions. A powerful method for investigating proteins within a native chromatin environment in the cell is chromatin immunoprecipitation (ChIP). Combined with the recent technological advancement in next generation sequencing, the ChIP assay can map the exact binding sites of a protein of interest across the entire genome. Here we describe a-step-by step protocol for ChIP followed by library preparation for ChIP-seq from yeast cells. Chromatin immunoprecipitation (ChIP) is a powerful method for assaying protein–DNA binding in vivo and is broadly used to estimate the density of DNA-bound proteins at specific sites in the genome. ChIP is a multistep assay and every step needs to be optimized for consistent results. Briefly, protein–DNA associations are immobilized by cross-linking with formaldehyde [1,2,3] before shearing the chromatin, either mechanically [4] or by enzymatic digestion [5] into DNA fragments of average size 200–500bp. Specific cross-linked protein–DNA complexes are then isolated by immunoprecipitation using an antibody to the protein of interest. Finally, the cross-links are reversed, and the retrieved DNA is analyzed to determine the sequences bound by the protein. ChIP followed by quantitative real-time PCR (ChIP-qPCR), using specific primers, can be used to measure protein association and relative abundance at a particular genomic locus. Alternatively, ChIP can be combined with next generation sequencing (ChIP-seq) to provide a genome-wide view of protein occupancy. While ChIP-seq allows for relative protein abundance at distinct chromosomal addresses to be compared within a sample, differences between samples cannot be quantified without introducing a method to normalize. Typically, this involves “spike in” of a known amount of DNA or cross-linked cells from a different species, with sufficient sequence divergence from the organism of interest to allow sequencing reads to be confidently distinguished bioinformatically [6,7,8]. This technique, referred to as calibrated ChIP-seq, makes it possible to quantitate genome-wide changes in the distribution of an epitope tagged protein and allows for quantification of differences in occupancy between experimental samples [8]. Calibrated ChIP-seq requires that both calibration and experimental organisms carry the same epitope tag and can be immunoprecipitated by the same protocol. For this protocol we use S. pombe to calibrate S. cerevisiae, a combination that also allows us to invert the roles, that is, calibrate S. pombe with S. cerevisiae. The ChIP method described here has been optimized for use with chromatin from two species of yeast,S. cerevisiae and S. pombe; however, it should be easy to adapt it for use with other chromatin sources. To demonstrate the robustness of our ChIP and library preparation protocols we performed ChIP against the Scc1 subunit of the cohesin multiprotein complex, tagged with the 6HA epitope [9,10,11] . We have also used a similar protocol for the condensin subunit Brn1 [12] and for the meiotic counterpart of cohesin, Rec8 [13]. Here, we outline in detail an optimized protocol for cross-linking and harvesting cells, fragmenting chromatin, immunoprecipitating the desired protein–DNA complexes, and preparing the library for sequencing on the Illumina MiniSeq platform. A schematic stepwise representation of the method is illustrated in Fig.1. References: Solomon MJ, Varshavsky A (1985) Formaldehyde-mediated DNA-protein crosslinking: a probe for in vivo chromatin structures. Proc Natl Acad Sci U S A 82(19):6470–6474 Solomon MJ, Larsen PL, Varshavsky A (1988) Mapping protein-DNA interactions in vivo with formaldehyde: evidence that histone H4 is retained on a highly transcribed gene. Cell 53(6):937–947 Gilmour DS, Lis JT (1984) Detecting protein-DNA interactions in vivo: distribution of RNA polymerase on specific bacterial genes. Proc Natl Acad Sci U S A 81(14):4275–4279 Kuo MH, Allis CD (1999) In vivo cross-linking and immunoprecipitation for studying dynamic protein:DNA associations in a chromatin environment. Methods 19(3):425–433.https://doi.org/10.1006/meth.1999.0879 Thorne AW, Myers FA, Hebbes TR (2004) Native chromatin immunoprecipitation. Methods Mol Biol 287:21–44.https://doi.org/10.1385/1-59259-828-5:021 Bonhoure N, Bounova G, Bernasconi D, Praz V, Lammers F, Canella D, Willis IM, Herr W, Hernandez N, Delorenzi M, Cycli XC (2014) Quantifying ChIP-seq data: a spiking method providing an internal reference for sample-to-sample normalization. Genome Res 24(7):1157–1168.https://doi.org/10.1101/gr.168260.113 Orlando DA, Chen MW, Brown VE, Solanki S, Choi YJ, Olson ER, Fritz CC, Bradner JE, Guenther MG (2014) Quantitative ChIP-Seq normalization reveals global modulation of the epigenome. Cell Rep 9(3):1163–1170.https://doi.org/10.1016/j.celrep.2014.10.018 Hu B, Petela N, Kurze A, Chan KL, Chapard C, Nasmyth K (2015) Biological chromodynamics: a general method for measuring protein occupancy across the genome by calibrating ChIP-seq. Nucleic Acids Res 43(20):e132.https://doi.org/10.1093/nar/gkv670 Fernius J, Marston AL (2009) Establishment of cohesion at the pericentromere by the Ctf19 kinetochore subcomplex and the replication fork-associated factor, Csm3. PLoS Genet 5(9):e1000629.https://doi.org/10.1371/journal.pgen.1000629 Fernius J, Nerusheva OO, Galander S, Alves Fde L, Rappsilber J, Marston AL (2013) Cohesin-dependent association of scc2/4 with the centromere initiates pericentromeric cohesion establishment. Curr Biol 23(7):599–606.https://doi.org/10.1016/j.cub.2013.02.022 Hinshaw SM, Makrantoni V, Kerr A, Marston AL, Harrison SC (2015) Structural evidence for Scc4-dependent localization of cohesin loading. elife 4:e06057.https://doi.org/10.7554/eLife.06057 Verzijlbergen KF, Nerusheva OO, Kelly D, Kerr A, Clift D, de Lima Alves F, Rappsilber J, Marston AL (2014) Shugoshin biases chromosomes for biorientation through condensin recruitment to the pericentromere. elife 3:e01374.https://doi.org/10.7554/eLife.01374 Vincenten N, Kuhl LM, Lam I, Oke A, Kerr AR, Hochwagen A, Fung J, Keeney S, Vader G, Marston AL (2015) The kinetochore prevents centromere-proximal crossover recombination during meiosis. elife 4.https://doi.org/10.7554/eLife.10850 Nelson JD, Denisenko O, Bomsztyk K (2006) Protocol for the fast chromatin immunoprecipitation (ChIP) method. Nat Protoc 1(1):179–185.https://doi.org/10.1038/nprot.2006.27 Cockram CA, Filatenkova M, Danos V, El Karoui M, Leach DR (2015) Quantitative genomic analysis of RecA protein binding during DNA double-strand break repair reveals RecBCD action in vivo. PNAS Aug 25;112(34):E4735–42. DeAngelis MM, Wang DG, Hawkins TL (1995) Solid-phase reversible immobilization for the isolation of PCR products. Nucleic Acids Res 23(22):4742–4743 Ewels P, Magnusson M, Lundin S, Kaller M (2016) MultiQC: summarize analysis results for multiple tools and samples in a single report. Bioinformatics 32(19):3047–3048.https://doi.org/10.1093/bioinformatics/btw354 Li H (2018) Minimap2: pairwise alignment for nucleotide sequences. Bioinformatics 34(18):3094–3100.https://doi.org/10.1093/bioinformatics/bty191 Li H, Handsaker B, Wysoker A, Fennell T, Ruan J, Homer N, Marth G, Abecasis G, Durbin R, 1000 Genome Project Data Processing Subgroup (2009) The sequence alignment/map format and SAMtools. Bioinformatics 25(16):2078–2079.https://doi.org/10.1093/bioinformatics/btp352 Quinlan AR, Hall IM (2010) BEDTools: a flexible suite of utilities for comparing genomic features. Bioinformatics 26(6):841–842.https://doi.org/10.1093/bioinformatics/btq033 Robinson JT, Thorvaldsdottir H, Winckler W, Guttman M, Lander ES, Getz G, Mesirov JP (2011) Integrative genomics viewer. Nat Biotechnol 29(1):24–26.https://doi.org/10.1038/nbt.1754 Tian B, Yang J, Brasier AR (2012) Two-step cross-linking for analysis of protein-chromatin interactions. Methods Mol Biol 809:105–120.https://doi.org/10.1007/978-1-61779-376-9_7 Craig DW, Pearson JV, Szelinger S, Sekar A, Redman M, Corneveaux JJ, Pawlowski TL, Laub T, Nunn G, Stephan DA, Homer N, Huentelman MJ (2008) Identification of genetic variants using bar-coded multiplexed sequencing. Nat Methods 5(10):887–893.https://doi.org/10.1038/nmeth.1251 Ford E, Nikopoulou C, Kokkalis A, Thanos D (2014) A method for generating highly multiplexed ChIP-seq libraries. BMC Res Notes 7:312. https://doi.org/10.1186/1756-0500-7-312 Acknowledgements: We are grateful to Manu Shukla for discussions and comments on the ChIP-seq library preparation and for kindly providing a representative Bioanalyzer image, Nicholas Toda, Jesus Torres-Garcia, and Flora Paldi for sharing tips on the ChIP-seq library protocol and Stefan Galangher and Lesley Clayton for general comments on the manuscript. This work was funded by Wellcome through a Senior Research Fellowship to AM and a Wellcome Centre core grant [107827 and 203149].

A plethora of biological processes like gene transcription, DNA replication, DNA recombination, and chromosome segregation are mediated through protein–DNA interactions. A powerful method for investigating proteins within a native chromatin environment in the cell is chromatin immunoprecipitation (ChIP). Combined with the recent technological advancement in next generation sequencing, the ChIP assay can map the exact binding sites of a protein of interest across the entire genome. Here we describe a-step-by step protocol for ChIP followed by library preparation for ChIP-seq from yeast cells.

The Small Modular Reactor (SMR) concept is designed such that it will solve some of the construction problems of large reactors. SMRs are designed to be “shop fabricated and then transported as modules to the sites for installation” (IAEA, 2018). As a consequence they theoretically have shorter build schedules and require less capital investment (Locatelli et al., 2014). Factory built modules can also increase safety and productivity, due to higher quality tools and inspection available. A literature review has highlighted substantial work has been undertaken in the research, development and construction of different types of reactors and reactor modules but the design of balance of plant modules has not been extensively researched (Wrigley et al., 2018). The focus of this paper is a case study for balance of plant modules in a light water reactor which also could have applications to other reactor types. Modules that are designed for factory build and transport may be built in a standardized module approach. By maximizing module size for transport, this maximizes work offsite, to achieve the cost and schedule savings associated. A design method needs to be developed to help support this approach. To enable this, a three step method is proposed: group components into modules, layout the modules and arrange components inside the modules. The Shearon Harris nuclear power plant was chosen for its publically available data. A previous study on this plant used matrix reordering techniques to group components and heuristically assign them to large modules, built for construction in an assembly area on site, highlighting a potential capital cost savings of 15%. This paper utilizes the same allocation of components to modules as the previous study but aims to undertake the challenge of how balance of plant modules should be arranged. The literature review highlighted that although the facility and plant layout problem has been extensively researched, mathematical layout optimization has not been applied to nuclear power plants. Many techniques for layout optimization have been developed for facilities and process plants however. The work in this paper develops an optimization model using a genetic algorithm for module layout and allocation within a nuclear power plant. This paper analysed two configurations of modules, where balance of plant modules are located on either one or two sides of the nuclear island. The objective function was to minimise pipe length. In the original research, where the plant was configured for assembly on site, the balance of plant modules are located around three sides of the nuclear island. The objective function was calculated at 14,914. As the distances are calculated rectilinearly, this number would be higher in reality as pipework has to be routed around containment. The optimization reduced the objective function by 33.9% and 37.8% for the three and four floor layouts respectively when balance of plant modules are located on two sides of the nuclear island. Furthermore, when modules are located on one side of the nuclear island, the objective function was reduced by 45.4% and 46.1% for three and four floor layouts respectively. This will reduce materials used, reduce build time and hence reduce the cost of a nuclear power plant. This method will also save design time when developing the layout of modules around the plant.

Hard chromium plate (HCP) has been the wear resistant coating of choice in the nuclear industry for decades, but new protective coatings are required as a result of the hazardous nature of Cr(VI) compounds used in electroplating. This study compares the wear performance of candidate replacements materials, Cr2O3 and Cr3C2–NiCr. These two coatings are also compared with HCP and a WC-(W,Cr)2C–Ni coating assessed in an earlier publication. The Cr2O3 and Cr3C2–NiCr coatings were supplied having been applied to Inconel 625 substrates using high velocity oxy fuel (HVOF) and thermal detonation gun spray techniques, respectively. A ball-on-flat sliding wear configuration was used with three environments: dry, deionised water, and borated water to partially simulate nuclear reactor water chemistry. Wear rates were measured using both volume and mass standard metrics. The wear surface samples were characterised using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) in order to establish the operative wear mechanisms. All three candidate coating materials exhibited similar wear performance to HCP in the three test environments. There was, however, enough of a difference between performance in deionised and borated water, to merit the use of borated water in future testing. The data gathered using SEM and XPS provided insight into the wear mechanisms. These include both particle pull-out and tribolayer formation. The XPS data revealed that Cr3C2 is preferentially removed from the Cr3C2–NiCr coating during wear testing in a borated water environment.

The influence of high-energy (1.6 MeV) Ar

Charge cycling cross sections of lithium and helium ions are measured for atomic metal films of titanium, zirconium and copper. The material dependence of the measured charge state fractions is investigated and compared with the material density, electron density, mean ionization potential and Fermi level. The experimental data quantitatively agrees with previously documented charge exchange cross sections for thin films and shows the expected increase in the fraction of higher charge states with increasing velocity, over the ion velocity range considered. There is an observable material dependence of the charge state fraction. The measured charge state distributions are expressed as a mean charge state and compared with various mean and effective charge formalisms. The effective charge models are demonstrated to be inadequate representations of the measured mean charge states for the ions and films probed in this study.

Off-Site Modular Construction (OSMC) research has been a burgeoning research area over the past two decades due to low productivity of traditional construction methods. Some large Gen 3 reactors may employ an on-site assembly area similar to shipbuilding techniques. This OSMC productivity has attracted the interest of the nuclear industry with over 50+ designs in commercial development. Off-site modular construction has been estimated to reduce the capital cost of an SMR by up to 37.98% compared to a stick-built method. The IAEA highlights the first commercial SMR “shop built and road transported to site” has an earliest operation date of 2026 (IAEA, 2018). This research paper aims to understand the current state of modular design in nuclear power by reviewing current literature with a systematic literature review. What can new small modular reactor designs learn from modularisation in large nuclear. What design and analysis techniques have been developed that may aid the design considering design, schedule, transportation and supply chain? What is the state of the art in the module design process? The research provides knowledge gaps and recommendations for further research.

Five new Tl(I) coordination compounds based on aryl monocyanoximes, such as phenylcyanoxime – HPhCO, 1, 2-fluorophenylcyanoxime – H(2F-PhCO, 2, 3-fluorophenylcyanoxime – H(3F-PhCO), 3, of TlL composition, and aryl biscyanoximes, such as 1,3-cyanoxime (benzene) – H2(1,3-BCO, 4 and 1,4-cyanoxime (benzene) – H2(1,4-BCO), 5 of Tl2L stoichiometry were synthesized and characterized using spectroscopic methods, thermal stability studies, and X-ray analysis. All obtained complexes represent coordination polymers of different complexity, ranging in dimensionality from 1D in Tl(2F-PhCO) to 3D in Tl2(1,3-BCO). The most interesting feature of all synthesized complexes is the formation of Tl2O2 rhombs: non planar and non-centrosymmetric in Tl(PhCO), and planar and centrosymmetric in the other three compounds. These rhombi are interconnected, forming zigzag and ladder-type polymers in which very short thallophilic Tl---Tl distances were observed. Thus, in the structure of Tl2(1,3-BCO) the closest distance between metal centers was found to be 3.670 A. This is the second shortest on-record intermetallic contact in non-organometallic and non-cluster, but Werner type complexes, and is close to that in metallic thallium: 3.456 A. In all five new coordination polymers the central atom has a stereo-active 6 s2 lone pair that significantly distorts the shape of the coordination polyhedron of Tl(I). The first time, Tl–O vibrations in Tl2O2 rhombs were observed in Raman spectra of the obtained complexes. Thermal analysis studies evidenced stability of all complexes, but Tl(PhCO), to ∼200 °C. The Tl2(1,3-BCO) compound demonstrates properties of the high energy compound, and violently exothermically decomposes at ∼255 °C with the release of a significant amount of kinetic energy. The final product of anaerobic decomposition of all studied Tl-cyanoximates is metallic thallium sponge.

The UK Small Modular Reactor (UKSMR) programme has been established to develop an SMR for the UK energy market. Developing an SMR is a multi-disciplinary technical challenge, involving nuclear physics, electrical, mechanical, design, management, safety, testing to name but a few. In 2016 Upadhyay & Jain performed a literature review on modularity in Nuclear Power. They concluded that although modularisation has been utilised in nuclear to reduce costs, more work needs to be done to “create effective modules”. Hohmann et al also concluded the same for defining modules in the chemical process plant industry. The aim of this paper is to further define modules with a particular focus on an SMR for the UK market, the UKSMR. The methods highlighted may be relevant and applied to other international SMR designs or other types of plant. An overview and examination of modularisation work in nuclear to date is provided. The different configurations are defined for the Nuclear Steam Supply System (NSSS) in primary circuits and then for Balance of Plant (BOP) modules. A top level design process has been defined to aid in the understanding of design choices for current reactors and to further assist designing balance of plant modules. The paper then highlights areas for additional research that may further support module design and definition.

Reconfigurable mechanisms are a relatively recent contribution to the field of mechanism design and authors have only just been producing real-life applications of these mechanisms. This paper builds on the application of two categories of reconfigurable mechanisms by elaborating on a generalised static balancing theory suggested in a previous review paper [1]. These categories are single loop mechanisms with one degree of freedom per mode, and single loop mechanisms with multiple degrees of freedom per mode. In this paper it is shown that all configurations of the single DoF mechanisms can be balanced using a single spring. The multiple DoF mechanisms can be balanced by balancing each link with respect to the previous link. These balancing strategies are mathematically shown to be valid. The balancing strategy is then applied to a reconfigurable rehabilitation mechanism for patients with a lower limb paralysis by Tseng et al. [2] of which a simulation and a prototype is made to validate the theory. From the simulation and prototype follows that the single spring balancing of multiple configurations of a single DoF mechanism is possible.

Summary Meiosis produces gametes through a specialized, two-step cell division, which is highly error prone in humans. Reductional meiosis I, where maternal and paternal chromosomes (homologs) segregate, is followed by equational meiosis II, where sister chromatids separate. Uniquely during meiosis I, sister kinetochores are monooriented and pericentromeric cohesin is protected. Here, we demonstrate that these key adaptations for reductional chromosome segregation are achieved through separable control of multiple kinases by the meiosis-I-specific budding yeast Spo13 protein. Recruitment of Polo kinase to kinetochores directs monoorientation, while independently, cohesin protection is achieved by containing the effects of cohesin kinases. Therefore, reductional chromosome segregation, the defining feature of meiosis, is established by multifaceted kinase control by a master regulator. The recent identification of Spo13 orthologs, fission yeast Moa1 and mouse MEIKIN, suggests that kinase coordination by a meiosis I regulator may be a general feature in the establishment of reductional chromosome segregation., Graphical Abstract, Highlights • Spo13 recruits Polo kinase to kinetochores to direct sister chromatid co-segregation • Kinetochore-associated Polo drives co-segregation independently of monopolin • Spo13 counteracts cohesin kinases to prevent premature loss of centromeric cohesion • Spo13 restricts CK1δ to allow shugoshin reaccumulation after meiosis I, Segregation of homologs—rather than sister chromatids—is unique to meiosis I. Galander et al. show that the meiosis-I-specific Spo13 protein prevents sister chromatid segregation by controlling the effects of multiple kinases to both enforce sister kinetochore co-orientation and prevent premature loss of cohesion.

The half-life of the neutron-rich nuclide $^{60}\mathrm{Fe}$ has been in dispute in recent years. A measurement in 2009 published a value of $(2.62\ifmmode\pm\else\textpm\fi{}0.04)\ifmmode\times\else\texttimes\fi{}{10}^{6}$ years, almost twice that of the previously accepted value from 1984 of $(1.49\ifmmode\pm\else\textpm\fi{}0.27)\ifmmode\times\else\texttimes\fi{}{10}^{6}$ yr. This longer half-life was confirmed in 2015 by a second measurement, resulting in a value of $(2.50\ifmmode\pm\else\textpm\fi{}0.12)\ifmmode\times\else\texttimes\fi{}{10}^{6}$ yr. All three half-life measurements used the grow-in of the $\ensuremath{\gamma}$-ray lines in $^{60}\mathrm{Ni}$ from the decay of the ground state of $^{60}\mathrm{Co}$ (${t}_{1/2}=5.27$ yr) to determine the activity of a sample with a known number of $^{60}\mathrm{Fe}$ atoms. In contrast, the work presented here measured the $^{60}\mathrm{Fe}$ activity directly via the 58.6 keV $\ensuremath{\gamma}$-ray line from the short-lived isomeric state of $^{60}\mathrm{Co}$ (${t}_{1/2}=10.5$ min), thus being independent of any possible contamination from long-lived $^{60\mathrm{g}}\mathrm{Co}$. A fraction of the material from the 2015 experiment with a known number of $^{60}\mathrm{Fe}$ atoms was used for the activity measurement, resulting in a half-life value of $(2.72\ifmmode\pm\else\textpm\fi{}0.16)\ifmmode\times\else\texttimes\fi{}{10}^{6}$ yr, confirming again the longer half-life. In addition, $^{60}\mathrm{Fe}/^{56}\mathrm{Fe}$ isotopic ratios of samples with two different dilutions of this material were measured with accelerator mass spectrometry to determine the number of $^{60}\mathrm{Fe}$ atoms. Combining this with our activity measurement resulted in a half-life value of $(2.69\ifmmode\pm\else\textpm\fi{}0.28)\ifmmode\times\else\texttimes\fi{}{10}^{6}$ yr, again agreeing with the longer half-life.

The influence of high-energy (1.6 MeV) Ar2+ irradiation on the interfacial interaction between cerium oxide thin films (∼15 nm) with a SiO2/Si substrate is investigated using transmission electron microscopy, ultrahigh vacuum x-ray photoelectron spectroscopy (XPS), and a carbon monoxide (CO) oxidation catalytic reaction using ambient pressure XPS. The combination of these methods allows probing the dynamics of vacancy generation and its relation to chemical interactions at the CeO2/SiO2/Si interface. The results suggest that irradiation causes amorphization of some portion of CeO2 at the CeO2/SiO2/Si interface and creates oxygen vacancies due to the formation of Ce2O3 at room temperature. The subsequent ultra-high-vacuum annealing of irradiated films increases the concentration of Ce2O3 with the simultaneous growth of the SiO2 layer. Interactions with CO molecules result in an additional reduction of cerium and promote the transition of Ce2O3 to a silicate compound. Thermal annealing of thin films exposed to oxygen or carbon monoxide shows that the silicate phase is highly stabile even at 450 °C.

The necessity to handle heat loads in the MW/m2 range has become increasingly prevalent in a number of industries. Termed high-heat flux cooling, some of the most challenging conditions in this field occur at the first wall and divertor regions of a fusion tokamak. Steady-state heat fluxes here may reach values in excess of 10 MW/m2 in some areas for a first stage DEMO. The situation is exasperated further by the environment within the machine, which severely alters material properties with time. Even coolant choice itself can have an impact beyond thermal considerations through tritium inventory and neutron activation. Successfully addressing these issues is of critical importance to the development of commercial fusion power. A number of heat sink modules utilising jet impingement in a flat plate geometry were manufactured using diffusion bonding. Each sample produced was subject to leak and hydrostatic pressure measurements, together with further non-destructive analyses. Thermo-fluid measurements were performed on the components in a purpose built facility employing water as the coolant at pressures of up to 200 bar. To replicate the thermal boundary conditions a resistive thin-film heater technique was utilised. This allowed heat fluxes in the MW/m2 range to be applied to the modules. The results indicate that the concept may be a viable alternative heat sink candidate for first wall or divertor applications in a DEMO, but that further research is required to optimise certain aspects of the design.

Equilibrium charge state fractions have been measured for 3–7 MeV lithium, boron and carbon ions passing through thin foils of copper, silver, and gold. The current results are combined with other low-Z ion data from the literature to give the relative influence of different target materials on charge exchange processes. The mean charge of the projectile, the functional form of the charge state distribution, and the charge state distribution width are parameters used to examine the effects of the electronic structure on charge exchange for various target-projectile combinations. Projectile shell structure is found to have a large influence on the widths of the charge state.

This paper presents a new type of series ac-processing pickup used in inductive-power-transfer applications. The proposed pickup uses an ac switch operating under zero-current-switching conditions in series with a resonant network to produce a controllable ac voltage source suitable for driving incandescent lights. When a rectifier is cascaded onto this pickup, it can also produce a precisely controlled dc voltage. This topology eliminates the need to use an extra buck converter after the traditional series pickup for controlling the output load voltage to a desired value, which may be different from the induced voltage of the pickup. Furthermore, this pickup has the ability to control the inductor current directly, and hence, eliminate the transient inrush current at startup for the series-tuned resonant tank. The circuit is analytically analyzed and the maximum efficiency for a 1.2-kW prototype is measured to be 93%.

We report on the growth of ultra-thin bismuth (Bi) films on the basal plane of highly ordered pyrolitic graphite (HOPG) substrates; we investigate the morphologies of films grown at room temperature and then annealed at high temperature, and the morphologies of Bi structures grown at high temperature. Films grown at room temperature nucleate flat islands on the HOPG terraces, and 1D nanorods from HOPG step edges, the islands and rods both have heights in the range 1–3 nm. During annealing, the flat islands break up into groups of aligned, ∼ 2.5 nm tall rods. For films grown at high temperature, terrace nucleation is almost nonexistent, and 1D structures grow from step edges, with heights up to 30 nm. Finally, we observe rods with distinctively different morphologies corresponding to (110) and (111) orientations, and infer a surface energy driven Bi(110) to Bi(111) orientation transition. We speculate that the dominant mechanism for the reorientation is coalescence.

Equilibrium charge state distributions of boron and carbon ions through carbon and aluminum targets were measured with an energy range of 3–6 MeV. Comparisons of the data with relevant semi-empirical models for the equilibrium mean charge states and for the charge state distribution widths could provide valuable insight on the underlying mechanisms for a fast ion to lose or capture electrons. In-depth examinations of the experimental results in combination with semi-empirical models suggest that equilibrium charge state distributions are well represented by Gaussian distributions.

Treatment delivery with active beam scanning in proton radiation therapy introduces the problem of interplay effects when pencil beam motion occurs on a similar time scale as intra-fractional tumor motion. In situations where fractionation may not provide enough repetition to blur the effects of interplay, repeated delivery or 'repainting' of each field several times within a fraction has been suggested. The purpose of this work was to investigate the effectiveness of different repainting strategies in proton beam scanning. To assess the dosimetric impact of interplay effects, we performed a series of simulations considering the following parameters: tumor motion amplitude, breathing period, asymmetry in the motion trajectory for the target and time required to change the beam energy for the delivery system. Several repainting strategies were compared in terms of potential vulnerability to a dose delivery error. Breathing motion perpendicular to the beam direction (representing superior-inferior type tumor motion in patients) was considered and modeled as an asymmetric sine function with a peak-to-peak amplitude of between 10 and 30 mm. The results show that motion effects cause a narrowing of the high-dose profile and widening of the penumbra. The 90% isodose area was reduced significantly when considering a large motion amplitude of 3 cm. The broadening of the penumbra appears to depend only on the amplitude of tumor motion (assuming harmonic motion). The delivered dose exhibits a shift of 10-15% of the tumor amplitude (or 1-5 mm) in the caudal direction due to breathing asymmetry observed for both sin(4)(x) and sin(6)(x) motion. Of the five repainting techniques studied, so-called 'breath sampling' turned out to be most effective in reducing dose errors with a minimal increase in treatment time. In this method, each energy level is repainted at several evenly spaced times within one breathing period. To keep dose delivery errors below 5% while minimizing treatment time, it is recommended that breath sampling repainting be employed using 5-10 paintings per field for an assumed tumor volume of 8.5 x 8.5 x 10 cm(3). For smaller tumor volumes more repaintings will be required, while for larger volumes five repaintings should be sufficient to achieve the required dose accuracy.

We report on the first measurement of 39Ar in argon from underground natural gas reservoirs. The gas stored in the US National Helium Reserve was found to contain a low level of 39Ar. The ratio of 39Ar to stable argon was found to be, 6 pages, 2 figures, 2 tables

The purpose of this study was to develop a novel algorithm to create a robust internal respiratory signal (IRS) for retrospective sorting of four-dimensional (4D) computed tomography (CT) images.The proposed algorithm combines information from the Fourier transform of the CT images and from internal anatomical features to form the IRS. The algorithm first extracts potential respiratory signals from low-frequency components in the Fourier space and selected anatomical features in the image space. A clustering algorithm then constructs groups of potential respiratory signals with similar temporal oscillation patterns. The clustered group with the largest number of similar signals is chosen to form the final IRS. To evaluate the performance of the proposed algorithm, the IRS was computed and compared with the external respiratory signal from the real-time position management (RPM) system on 80 patients.In 72 (90%) of the 4D CT data sets tested, the IRS computed by the authors' proposed algorithm matched with the RPM signal based on their normalized cross correlation. For these data sets with matching respiratory signals, the average difference between the end inspiration times (Δtins) in the IRS and RPM signal was 0.11 s, and only 2.1% of Δtins were more than 0.5 s apart. In the eight (10%) 4D CT data sets in which the IRS and the RPM signal did not match, the average Δtins was 0.73 s in the nonmatching couch positions, and 35.4% of them had a Δtins greater than 0.5 s. At couch positions in which IRS did not match the RPM signal, a correlation-based metric indicated poorer matching of neighboring couch positions in the RPM-sorted images. This implied that, when IRS did not match the RPM signal, the images sorted using the IRS showed fewer artifacts than the clinical images sorted using the RPM signal.The authors' proposed algorithm can generate robust IRSs that can be used for retrospective sorting of 4D CT data. The algorithm is completely automatic and requires very little processing time. The algorithm is cost efficient and can be easily adopted for everyday clinical use.

Nitrosation of 2-chlorophenyl acetonitrile with t-butylnitrite under basic conditions (Meyer reaction) resulted in a high-yield preparation of the first substituted arylcyanoxime, 2-chlorophenyl(oximino)acetonitrile, H(2Cl–PhCO) (HL). The obtained cyanoxime is readily deprotonated in solution by metal hydroxides or carbonates with the formation of yellow sodium, tetrabutylammonium, thallium(I) and silver(I) derivatives. The crystal structure of the Tl(I) complex was determined. Thallium(I) salt (TlL) crystallizes in the monoclinic space group P21 n with a = 3.8382(7), b = 11.0065(18), c = 20.901(4) A, and β = 92.447(3)°, V = 882.2(3) A3, Z = 4; T = 193 K (Mo Kα radiation). The structure was solved by direct methods to a final R of 0.0689 (wR2 = 0.1650) for I > 2σ(I). The crystal structure of the complex is a one-dimensional coordination polymer that consists of centrosymmetric [TlL]2 dimers in which Tl2O2 rhombohedra are connected to each other at 90.72°. The crystal structure of TlL is an interesting exa...

Background: Optical potentials are crucial ingredients for the prediction of nuclear reaction rates needed in simulations of the astrophysical $\ensuremath{\gamma}$ process. Associated uncertainties are particularly large for reactions involving $\ensuremath{\alpha}$ particles. This includes $(\ensuremath{\gamma},\ensuremath{\alpha})$ reactions which are of special importance in the $\ensuremath{\gamma}$ process.Purpose: The measurement of $(\ensuremath{\alpha},n)$ reactions allows for an optimization of currently used $\ensuremath{\alpha}$-nucleus potentials. The reactions $^{165}\mathrm{Ho}$$(\ensuremath{\alpha},n)$ and $^{166}\mathrm{Er}$$(\ensuremath{\alpha},n)$ probe the optical model in a mass region where $\ensuremath{\gamma}$ process calculations exhibit an underproduction of $p$ nuclei which is not yet understood.Method: To investigate the energy-dependent cross sections of the reactions $^{165}\mathrm{Ho}$$(\ensuremath{\alpha},n)$ and $^{166}\mathrm{Er}$$(\ensuremath{\alpha},n)$ close to the reaction threshold, self-supporting metallic foils were irradiated with $\ensuremath{\alpha}$ particles using the FN tandem Van de Graaff accelerator at the University of Notre Dame. The induced activity was determined afterwards by monitoring the specific $\ensuremath{\beta}$-decay channels.Results: Hauser-Feshbach predictions with a widely used global $\ensuremath{\alpha}$ potential describe the data well at energies where the cross sections are almost exclusively sensitive to the $\ensuremath{\alpha}$ widths. Increasing discrepancies appear towards the reaction threshold at lower energy.Conclusions: The tested global $\ensuremath{\alpha}$ potential is suitable at energies above 14 MeV, while a modification seems necessary close to the reaction threshold. Since the $\ensuremath{\gamma}$ and neutron widths show non-negligible impact on the predictions, complementary data are required to judge whether or not the discrepancies found can be solely assigned to the $\ensuremath{\alpha}$ width.

It is well known that the Chinese language does not have functional equivalents of the English definite and indefinite article. Correspondingly, there is plenty of observational evidence that Chinese learners have difficulty with the article system in English. In particular, these learners have a marked tendency to omit the article where native speakers of English would use one. In this article we report the results of an experimental investigation of the variable use of the definite and indefinite articles by 18 Chinese learners of English. A referential communication task was used to elicit samples of the speech of these learners which was rich in referring noun phrases. From the resulting corpus 1884 noun phrases were coded, using a taxonomy based on Hawkins' (1978) description of the definite and indefinite articles and demonstratives in English. The analysis shows an overall rate of 78% suppliance of articles in contexts where a native speaker would use the definite or indefinite article. Of the remaining 22% of contexts where articles are not used, we found that many of the instances of nonsuppliance of articles could be explained by three principles: 1) a syntactic principle of ‘determiner drop’, whereby an NP with definite or indefinite reference need not be overtly marked for [± definiteness] if it is included in the scope of the determiner of a preceding NP; 2) a ‘recoverability’ principle, whereby an NP need not be marked for [± definiteness] if the information encoded in this feature is recoverable from the context; and 3) a ‘lexical transfer principle’, whereby some of these learners are using demonstratives (particularly this) and the numeral one as markers of definiteness and indefiniteness respectively. However, these principles do not account for all the instances of non-native-like usage in the corpus. There remains a residue of 206 noun phrases without articles in contexts where native speakers would use an article.There are identical contexts, moreover, where these learners use the articles. We suggest that this evidence of unsystematic variation in the use of the articles by these learners lends support to the hypothesis that the optionality in the use of articles is due to difficulty acquiring the correct mapping from the surface features of definiteness and referentiality ( the, a, and the zero article Ø) onto the abstract features of the DP.

Short-lived radionuclides (SLRs) with lifetimes τ < 100 Myr are known to have been extant when the Solar System formed over 4.5 billion years ago. Identifying the sources of SLRs is important for understanding the time scales of Solar System formation and processes that occurred early in its history. Extinct 36Cl (t1/2= 0.301 Myr) is thought to have been produced by interaction of solar energetic particles, emitted by the young Sun, with gas and dust in the nascent Solar System. However, models that calculate SLR production in the early Solar System lack experimental data for the 36Cl production reactions. We present here the first measurement of the cross section of one of the main 36Cl production reactions, 33S(α,p)36Cl, in the energy range 0.70–2.42 MeV/nucleon. The cross-section measurement was performed by bombarding a target and collecting the recoiled 36Cl atoms produced in the reaction, chemically processing the samples, and measuring the 36Cl/Cl ratio of the activated samples with accelerator mass spectrometry. The experimental results were found to be systematically higher than the cross sections used in previous local irradiation models and other Hauser-Feshbach calculated predictions. However, the effects of the experimentally measured cross sections on the modeled production of 36Cl in the early Solar System were found to be minimal. Reaction channels involving S targets dominate 36Cl production, but the astrophysical event parameters can dramatically change each reaction's relative contribution.

Cross section measurements of the reactions ${}^{90,92}$Zr($p$,$\ensuremath{\gamma}$)${}^{91,93}$Nb were performed using the National Superconducting Cyclotron Laboratory Summing NaI(Tl) detector at the University of Notre Dame. These reactions are part of the nuclear reaction flow for the synthesis of the light $p$ nuclei. For the ${}^{90}$Zr($p$,$\ensuremath{\gamma}$)${}^{91}$Nb reaction the new measurement resolves the disagreement between previous results. For the ${}^{92}$Zr($p$,$\ensuremath{\gamma}$)${}^{93}$Nb reaction the present work reports the first measurement of this reaction cross section. Both reaction cross sections are compared to theoretical calculations and a very good agreement with the standard non-smoker model is observed.