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Based on radiocarbon dating, a tephra horizon, varve counts and palaeomagnetism, detailed age models covering the last ~24 k cal a bp, have been developed for the stratigraphy in the lakes Bolshoye Shchuchye and Maloye Shchuchye in the Polar Ural Mountains, Russia. The inclination curves from these lakes show nearly identical palaeomagnetic secular variations in the studied cores from both lakes, allowing for a precise correlation between the cores. A large and very distinct inclination deviation, named the Bolshoye Shchuchye Event, was identified in all cores retrieved from both lakes. It lasted over a period of 1245 years, from 20 470 to 19 225 cal a bp. The well-dated palaeomagnetic inclination graph offers a new possibility to correlate archives in this part of the Arctic for the last ~24 k cal a bp, probably also over longer distances. The sedimentation rate shows the same trend in all cores from both lakes, including high input during the Last Glacial Maximum and gradually lowering after ~18 k cal a bp to lower and stable Holocene values. publishedVersion

Liquid-crystal materials exhibiting up to three nematic phases are reported. Dielectric response measurements show that while the lower temperature nematic phase has ferroelectric order and the highest temperature nematic phase is apolar, the intermediate phase has local antiferroelectric order. The modification of the molecular structure by increasing the number of lateral fluorine substituents leads to one of the materials showing a direct isotropic- ferronematic phase transition.

Financial support for this work was provided by NERC Doctoral Training Partnership Ph.D. studentship NE/L002558/1 to Polly I. J. Thompson. We explore the effect small-scale surface features have on influencing the morphology and grain-size distribution (GSD) of tephra layers within the Quaternary stratigraphy of sub-polar landscapes. Icelandic thúfur, small cryogenic earth mounds, are used to assess how and why the morphology and GSD of tephra layers vary over such formations. Through measurement of tephra layer thickness and GSD, Hekla 1947 and Grímsvötn 2011 tephra layers are analysed. Results indicate that such microtopographic features do indeed alter the form of tephra deposits and therefore the tephra layer that is preserved in the stratigraphy. Tephra thickness is significantly greater in hollows than on the thúfur crests. There is greater variation in tephra thickness measurements from thúfur in comparison to control measurements from a surface where thúfur are absent. Thúfur crests contain larger grain sizes than hollows, for both H1947 and G2011 tephras; however this was only statistically significant for the G2011 tephra. Such morphological patterns are thought to arise from an interplay of tephra characteristics, altered topography from the thúfur formations and earth surface processes operating at the sites. This study provides insight into the potential of tephra layer morphology and internal structures as indicators of Quaternary landforms and processes. Additionally, it provides important context for the appropriate sampling of tephra layers to infer volcanological processes, as the characteristics of preserved layers do not necessarily reflect those of the original fall-out. Publisher PDF

Puncturing and shortening are two common ways to achieve rate‐compatible non‐systematic polar codes (NSPCs). Systematic polar codes (SPCs) have been shown to outperform NSPCs with the same encoding and decoding complexity. However, rate‐compatible SPCs have never been comprehensively studied in previous work. In this paper, two rate‐compatible algorithms for SPCs are first proposed: uniform puncturing (UP) algorithm and uniform shortening (US) algorithm, which are referred to as SPC‐UP and SPC‐US, respectively. In order to effectively estimate the maximum likelihood decoding performance of punctured and shortened polar codes, subsequently, a distance spectrum calculation algorithm based on successive cancellation list (SCL) decoder for rate‐compatible polar codes is proposed. Simulation results show that rate‐compatible SPCs yield better bit error rate performance than rate‐compatible NSPCs while they have the same frame error rate performance under different code rates and decoding algorithms. Eventually, union bounds that are obtained by the distance spectrum to provide the theoretical explanation for the superiority of rate‐compatible SPCs are utilised.

Ionic liquids (ILs) are an important class of media that are usually used in combination with polar solvents to reduce costs and tune their physicochemical properties. In this regard, it is essential to understand the influence of adding solvents on the properties of ILs. In this work, the micro-heterogeneity and H-bonding interactions between a hydroxyl-functionalized IL, [HOEmim][TFSI], and acetonitrile (ACN) were investigated by attenuated total reflection Fourier transform infrared spectroscopy and molecular simulations. All studied IL-ACN mixtures were found to deviate from the ideal mixtures. The degree of deviations reaches the maximum at about x(ACN)=0.7 with the presence of both homogeneous clusters of pure IL/ACN and heterogeneous clusters of IL-ACN. With the addition of ACN to IL, the mixtures undergo the transformation from "ACN solvated in [HOEmim][TFSI]" to "[HOEmim][TFSI] solvated in ACN". It is found that the newly formed H-bonding interactions between the IL and ACN is the main factor that contributes to the red shifts of O-H, C2 -H, C4,5 -H, and Calkyl -H of [HOEmim]+ cation, and the blue shifts of C-D, C≡N of ACN, and C-F, S=O of [TFSI]- anion. These in-depth studies on the mixtures of hydroxyl-functionalized IL and acetonitrile would help to understand the micro-heterogeneity and H-bonding interactions of miscible solutions and shed light on exploring their applications.

The discovery of new nonlinear optical (NLO) crystals with excellent properties is in urgently demand because of their ability to generate coherent light. Herein, we report an unique NLO lead bromide formate, KCs2 [Pb2 Br5 (HCOO)2 ], which has been synthesized by a mix-solvothermal method. KCs2 [Pb2 Br5 (HCOO)2 ] exhibits strong phase-matching second-harmonic generation (SHG) response (6.5×KDP), large birefringence (0.16@ 1064 nm), and a wide transparent window in most visible light and mid-IR region. Interestingly, KCs2 [Pb2 Br5 (HCOO)2 ] features a polar 3D lead-bromide framework in which adjacent Pb-Br layers containing coplanar Pb6 Br6 rings are not only parallel to each other, but also orient in the same direction. These oriented arrangements are responsible for the strong SHG response and large birefringence that are elucidated by both local dipole moment and theoretical calculations. This research provides a new strategy to explore subsequent NLO crystals.

Hydrolysis of trimethylaluminum (Me3 Al) in polar solvents can be monitored by electrospray ionization mass spectrometry (ESI-MS) using the donor additive octamethyltrisiloxane [(Me3 SiO)2 SiMe2 , OMTS]. Using hydrated salts, hydrolytic methylaluminoxane (h-MAO) features different anion distributions, depending on the conditions of synthesis, and different activator contents as measured by NMR spectroscopy. Non-hydrolytic MAO was prepared using trimethylboroxine. The properties of this material, which contains incorporated boron, differ significantly from h-MAO. In the case of MAO prepared by direct hydrolysis, oligomeric anions are observed to rapidly form, and then more slowly evolve into a mixture dominated by an anion with m/z 1375 with formula [(MeAlO)16 (Me3 Al)6 Me]- . Theoretical calculations predict that sheet structures with composition (MeAlO)n (Me3 Al)m are favoured over other motifs for MAO in the size range suggested by the ESI-MS experiments. A possible precursor to the m/z 1375 anion is a local minimum based on the free energy released upon hydrolysis of Me3 Al.

Hydrophilic interaction liquid chromatography is an alternative liquid chromatography mode for separation of polar compounds. In the recent years, this liquid chromatography mode has been recognized as an important solution for the analysis of compounds not amenable to reverse phase chromatography. In this work, we evaluated three different hydrophilic liquid chromatography stationary phases for the determination of 14 highly polar anionic molecules including pesticides such as glyphosate, glufosinate, ethephon and fosetyl, their main metabolites, and bromide, chlorate, and perchlorate. Several mobile phase compositions were evaluated combined with different gradients for the chromatographic run. The two columns that presented the best results were used to assess the performance for the determination of the 14 compounds in challenging highly complex feed materials. Very different matrix effects were observed for most of the compounds in each column, suggesting that different interactions can occur. Using isotopically labeled internal standards, acceptable quantitative performance and identification could be achieved down to 0.02 mg kg−1 (the lowest level tested) for most compounds. While one column was found to be favorable in terms of scope (suited for all 14 compounds), the other one was more suited for quantification and identification at lower levels, however, not for all analytes tested.

Ferroelectric spin crossover (SCO) behavior is demonstrated to occur in the cobalt(II) complex, [Co(FPh-terpy)2 ](BPh4 )2 ⋅3ac (1⋅3 ac; FPh-terpy=4'-((3-fluorophenyl)ethynyl)-2,2':6',2''-terpyridine) and is dependent on the degree of 180° flip-flop motion of the ligand's polar fluorophenyl ring. Single crystal X-ray structures at several temperatures confirmed the flip-flop motion of fluorobenzene ring and also gave evidence for the SCO behavior with the latter behavior also confirmed by magnetic susceptibility measurements. The molecular motion of the fluorobenzene ring was also revealed using solid-state 19 F NMR spectroscopy. Thus the SCO behavior is accompanied by the flip-flop motion of the fluorobenzene ring, leading to destabilization of the low spin cobalt(II) state; with the magnitude of rotation able to be controlled by an electric field. This first example of spin-state conversion being dependent on the molecular motion of a ligand-appended fluorobenzene ring in a SCO cobalt(II) compound provides new insight for the design of a new category of molecule-based magnetoelectric materials.

This articles develops a probabilistic scheme for the efficient controlling of hybrid microgrids seeing renewable sources and power storages. Owing to the increasing popularity of DC loads (such as laptops, phones, etc) and distributed generation, hybrid AC–DC microgrids can provide more advantages than AC microgrids by direct power supply to AC and DC loads individually. In order to incorporate the randomness of forecast values’ impacts, a new load flow approach constructed based on unscented transform is engaged to handle the uncertainties of electrical demand, bidding pricing, tidal turbine output power and photovoltaic output. As the planned problem is a hard non‐linear optimization, an influential polar crow search optimization algorithm is created to explore the problem domain. The polar version helps to search the optimal solution in a smoother and symmetrical space. Also, a new self‐adaptive three platform correction system is used to reinforce the search aptitude of crow search optimization algorithm when evading early convergence. The total energy losses has improved from the initial condition of 4,065.363 $ to 3,216.129, 3,147.086 and 3,276.394 $ in the 1st, 2nd and 3rd scenarios, respectively. Moreover, the second scenario could get into the best voltage profile with deviation of 0.077428 pu.

This is the peer reviewed version of the following article: Angewandte Chemie - International Edition 60.9 (2021): 4555-4560, which has been published in final form at https://doi.org/10.1002/anie.202013020. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited, Herein, a light-driven, atom-economical process that provides access to enantiomerically enriched substituted chiral 1-pyrroline derivatives is introduced. The strategy involves the distal functionalization of acyl heterocycles through a hydrogen-atom transfer (HAT) process and the use of tailor-made ketimines as reliable electrophilic partners. This transformation is translated into an enantiomerically controlled radical/polar cascade reaction in which water is produced as the sole by-product and stereoselectivity is dictated by coordination to a chiral-at-rhodium catalyst, Financial support was provided by the European Research Council (ERC-CoG, contract number: 647550, 861930), Spanish Government (RTI2018-095038-B-I00), “Comunidadde Madrid” and European Structural Funds (S2018/NMT-4367)

The physical and mechanical processes rooted in the hydrated, serpentinized mantle above subduction zones remain insufficiently explored despite fundamental implications for our understanding of rheology and fluid recycling along subduction interfaces. Through a field-based investigation, serpentinized peridotites and jadeitite samples from a fossil forearc mantle in the Polar Urals (Russia) are studied here to document fluid–rock interaction processes in the high-P field, as well as the long-term evolution of the base of the mantle wedge. Petrographic, geochemical and microstructural observations reveal a complex, protracted evolution of the jadeitite-forming fluid pathway throughout the gradual cooling of the forearc mantle and increasing serpentinization of the host. It is shown that the jadeitite lenses in the studied locality (a) derive for a large part from a trondhjemitic dyke earlier emplaced in a warm subduction environment, and (b) record the cooling of the subduction hangingwall under high-P conditions associated with increasing host serpentinization. In the studied locality, the majority of the jadeitites formed at relatively high temperatures (>600°C) by the influx of Na–Al-rich, slab-derived metamorphic fluids that were drained along the base of the mantle wedge, parallel to the subduction interface. Changes in bulk-rock geochemical signatures and in paragenetic sequences also constrain the compositional evolution of the fluid channelized along this drainage, with an increasing sedimentary component. The phlogopite-bearing walls of the dyke exhibit Rb–Sr and Ar–Ar ages ranging between c. 405 and c. 390 Ma, a range partly overlapping within uncertainty with the previously dated zircons from the jadeitite core (410–⁠400 Ma; U–Pb). This study opens a unique window on the pristine structures formed above the plate interface by melting and fluid–rock interaction in the early subduction stages, as well as their evolution during secular cooling of the base of the mantle wedge., Agence Nationale de la Recherche, Grant/ Award Number: 16C538. Nicolas Rividi and Michel Fialin (CAMPARIS) are acknowledged for assistance with Electron Probe measurements and mapping. Michael Bostock is acknowledged for insightful discussions. This study was supported by the IdEx ANR-18-IDEX-0001 through a chair attributed to SA. Oleg, Firaz and Katia are acknowledged for assistance during the two field expeditions. The article was prepared when working on the state budget topic IGG UB RAS AAAA-A18-118052590032-6. Two reviewers are acknowledged for constructive comments. This is IPGP contribution #40XX.

Polar materials attract wide research interest due to their unique properties, such as ferroelectricity and the bulk photovoltaic effect (BPVE), which are not accessible with nonpolar materials. However, in general, rationally designing polar materials is difficult because nonpolar materials are more favorable in terms of dipole-dipole interactions. Here, we report a rational strategy to form polar assemblies with bowl-shaped π-conjugated molecules and a molecular design principle for this strategy. We synthesized and thoroughly characterized 12 single crystals with the help of various theoretical calculations. Furthermore, we demonstrated that it can be possible to predict whether polar assemblies become more favorable or not by estimating their lattice energies. We believe that this study contributes to the development of organic polar materials and their related studies.

​According to Mayr, polar organic synthesis can be rationalized by a simple empirical relationship linking bimolecular rate constants to as few as three reactivity parameters. Here, we propose an extension to Mayr’s reactivity method that is rooted in uncertainty quantification and transforms the reactivity parameters into probability distributions. Through uncertainty propagation, these distributions can be transformed into uncertainty estimates for bimolecular rate constants. Chemists can exploit these virtual error bars to enhance synthesis planning and to decrease the ambiguity of conclusions drawn from experimental data. We demonstrate the above at the example of the reference data set released by Mayr and co-workers [J. Am. Chem. Soc. 2001, 123, 9500; J. Am. Chem. Soc. 2012, 134, 13902]. As by-product of the new approach, we obtain revised reactivity parameters for 36 π-nucleophiles and 32 benzhydrylium ions.

In this letter, a modified message passing algorithm to prevent short cycles in the factor graph is proposed and combined with a relaxation technique to improve the performance of cyclic redundancy check aided belief propagation decoding for polar codes. Numerical results show that the proposed scheme can achieve a 0.7 dB coding gain, for the code rate of 0.5 at the block error rate of 10−5 with a comparable average number of iterations over the pure belief propagation decoding scheme when the code block length is 1024.

To develop high-performance nonlinear optical (NLO) materials for infrared (IR) applications, we have applied a rational element-composition design strategy and investigated the unexplored PbO-PbCl2 -PbI2 system. By doing so, we discovered a new polar lead mixed oxyhalide, Pb18 O8 Cl15 I5 , the first synthetic metal oxyhalide combining both Cl- and I- . Pb18 O8 Cl15 I5 reveals an unprecedented structural feature with two different dimensional types of oxocentered Pb-O units, namely, [O4 Pb8 ]8+ clusters and [OPb2 ]2+ chains. Centimeter-sized single crystals of Pb18 O8 Cl15 I5 have been successfully grown under ambient conditions. Remarkably, Pb18 O8 Cl15 I5 satisfies all fundamental yet rigorous criteria for high-performance IR NLO materials, exhibiting the widest IR transparency (up to 16.0 μm) among oxide-based crystals, strong second-harmonic generation response (1.05×AgGaS2 ), superior birefringence (0.086 at 636 nm), and a high laser-induced damage threshold (8.5×AgGaS2 ).

Water molecules within a thin hydration layer, spontaneously generated on hydrophobic protein surfaces, are reported to form a poorly dynamic network structure. However, how such a water network affects the conformational change dynamics of polar groups has never been explored, although such polar groups play a critical role in protein-protein and protein-ligand interactions. In the present work, we utilized as model protein surfaces a series of self-assembled monolayers (SAMs) appended with polar (Fmoc) or ionic (FITC) fluorescent head groups that were tethered via a 1.5-nm-long flexible oligoether chain to a hydrophobic silicon wafer surface, which was densely covered with paraffinic chains. We found that, not only in deionized water but also in aqueous buffer, these oligoether-appended head groups at ambient temperatures both displayed an anomalously slow conformational change, which required ∼10 h to reach a thermodynamically equilibrated state. We suppose that these behaviors reflect the poorly dynamic and low-permittivity natures of the thin hydration layer.

Liquid state self‐assembly is important for the understanding of the complex structures developed in abiogenesis and biogenesis as well as for numerous potential technological applications. Herein we report the first body‐centered cubic liquid crystalline phase with 8‐connected network topology and open octahedral network structure. It is formed by dynamic soft self‐assembly of X‐shaped polyphiles with oligo(para‐phenylene‐ethynylene) cores. The π‐conjugated rods with perfluorinated inner benzene rings form networks conjoined by eight‐way junctions, which are formed by nano‐segregated spheres involving hydrogen‐bonded polar end groups, while the branched aliphatic chains at opposite sides of the cores fill the continuum. This novel cubic phase is based on the I‐WP minimal surface separating the frameworks of polyaromatic cores from the most disordered chain segments. It can also be considered as a dense sphere packing. Such liquid organic frameworks, representing hybrids of sphere packings and networks could be of interest for organic photonics and other technologies., The first 8‐connected network based on the I‐WP minimal surface is formed by dynamic soft self‐assembly of X‐shaped polyphiles with oligo(para‐phenylene‐ethynylene) cores. This Im 3‾ m cubic liquid‐crystalline phase is one of a new kind of cubic phases combining a network structure of rod‐bundles interconnected by polar spheres.

Hydration is a critical factor in the ligand binding process. Herein, to examine the hydration states of ligand binding sites, the three‐dimensional distribution function for the water oxygen site, gO(r), is computed for 3,706 ligand‐free protein structures based on the corresponding small molecule–protein complexes using the 3D‐RISM theory. For crystallographic waters (CWs) close to the ligand, gO(r) reveals that several CWs are stabilized by interaction networks formed between the ligand, CW, and protein. Based on the gO(r) for the crystallographic binding pose of the ligand, hydrogen bond interactions are dominant in the highly hydrated regions while weak interactions such as CH‐O are dominant in the moderately hydrated regions. The polar heteroatoms of the ligand occupy the highly hydrated and moderately hydrated regions in the crystallographic (correct) and wrongly docked (incorrect) poses, respectively. Thus, the gO(r) of polar heteroatoms may be used to distinguish the correct binding poses., The hydration states of ligand binding sites are comprehensively analyzed using a theory of solvation. An analysis of the hydration states at the positions of ligand heavy atoms indicates that the polar heteroatoms of the ligand tend to occupy highly hydrated regions in the correct ligand poses and moderately hydrated regions in the incorrect ligand poses, suggesting a way to distinguish these two poses.

The sorption of CO2 is often used to modify the macroscopic properties of liquids and solids. In the particular case of ionic liquids, different from molecular liquids, the sorption of CO2 may not induce volume expansions due to the strong Coulombic interactions between the ions of the fluid. However, a considerable viscosity decrease has been systematically observed. In order to understand the mechanisms of properties modifications in ionic fluids, herein we used Raman spectroscopy to probe the effect of CO2 on the structure of ionic liquids. It is shown that CO2 perturbs the electrostatic interactions between cations and anions, thus inducing a change in the polar domain of ionic liquids. It is observed that ionic liquids having bulkier ions are more prone to be perturbed by CO2 in comparison to ionic liquids having smaller ions. These results reveal new means of controlling the electrostatic forces between the ions and contributes to the mechanistic understanding of the modification of the macroscopic properties of ionic liquids by CO2 sorption.

We present time-resolved photometry of the cataclysmic variable (CV) PTF1J2224+17 obtained during 4 nights in October 2018 and January 2019 from Inastars observatory. The object is variable on a period of 103.82 min. Archival Catalina Real-Time Transient Survey (CRTS), PTF, and ZTF-data show frequent changes between high and low states. Based on its photometric properties and the cyclotron humps in the identification spectrum the object is certainly classified as an AM Herculis star (or polar) with a likely magnetic field strength of B ~ 65 MG. Its accretion duty cycle was estimated from nine years of photometric monitoring to be about 35 %., Comment: AN, in press (7 pages, 6 figures)