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The solution structure of 1.0 M Uranyl Chloride has been determined by the EPSR modelling of a combination of neutron scattering and EXAFS data. The experimental data show an equilibrium in solution between [UO

The order Chiroptera comprises all bat species and is the second-most diverse order of mammals. Organization of this diversity into well-delimited taxa embodying their evolutionary affinities remains challenging, particularly because the relationships among various groups at most taxonomic levels are not yet fully resolved. Historically, systematic questions were approached independently using tools and methodologies within researchers' individual expertise. With technological advances, this trend has shifted to more comprehensive analyses, merging independent datasets from various lines of research. Nevertheless, disagreements among phylogenetic relationships inferred from independent datasets, and derived from the complexity of modes of diversification and speciation, still preclude the achievement of a single, comprehensive, and stable classification framework for bats. In this context, integrative taxonomy uses complementarity among various disciplines to improve the outcome of hypothesis testing, which can be achieved by congruence or cumulation of datasets. Here, we provide a review of bat systematics, with emphasis on the instances where integrative taxonomy has proven to be crucial in delimitation of taxa. We focus on examples of true integration or integration using discrete data to support delimitation at different taxonomic levels. In addition, we discuss the difficulties associated with the integration of incongruent phylogenies, as well as how to incorporate information crucial to phylogenetic decisions from data not easily comparable to most common datasets. Our goal is to provide exemplar guidelines that can be useful to taxonomists for the creation of stable classifications without subjectivity and limitations of single datasets. Accordingly, we present a review of recent issues in chiropteran systematics, including comments on how the use of integrative taxonomy helped to solve them.

The solid state structure of the pentaborate anion templated by a doubly protonated TMEDA cation is reported. The structure is typical of this family of ligands, featuring extensive hydrogen bonding. Spectroscopic characterisation is also reported.

Classical and molecular cytogenetic methods were applied to study the karyotypes of one species of Hipposideridae and three taxa of the Rhinolophidae subgenus Aquias from Malaysian Borneo. Except for four chromosomal pairs with autapomorphic arm combinations, the karyotype of Coelops robinsoni was found to be similar to the closely related Aselliscus stoliczkanus. From the three Rhinolophus taxa studied, only R. trifoliatus was found to share the karyotype with conspecifics from Peninsular Malaysia. In contrast, the karyotype of R. luctus foetidus from Sarawak, Borneo differed in the composition of the Y-autosomal translocation products from the closely related R. morio from Peninsular Malaysia, formerly also a subspecies of R. luctus. Therefore, elevation to specific rank is suggested for R. l. foetidus. Examination of the chromosomal set of male R. sedulus specimens from Borneo with 2n = 45 and a Neo-X1X2Y sex chromosome system revealed extreme differences to the karyotype of specimens from Peninsular Malaysia with 2n = 28, to date also classified as R. sedulus. Therefore, with Sarawak, Borneo, as the type locality for R. sedulus, the taxon from Peninsular Malaysia is here described as a new species.

The benzimidazole derivative (E)-2-((4-(1H-benzo[d]imidazol-2-yl)phenylimino)methyl)-4-bromo phenol and the corresponding Zn(II), Ni(II), Cu(II), and Pd(II) complexes were prepared. The synthesized ligand and complexes were fully characterized and the ligand structure confirmed by single crystal X-ray diffraction analysis. The ability of this compound and its complexes to bind to DNA was first investigated with DNA thermal denaturation experiments, in general showing weak interactions. Additionally, UV–Vis absorption spectroscopy was used to assess the binding to DNA and the corresponding binding constants (Kb) were calculated suggesting an intercalative mode of binding for the benzimidazole ligand. All compounds were screened for their antibacterial activity and the Ni(II) complex showed promising results against all bacterial strains (Gram positive and Gram negative) while the rest of the compounds showed activity against selective strains.

L1s are transposable elements that move by a copy-and-paste mechanism that continuously increases their copy number in the genome, such that each genome has a record of the L1 history in that host lineage. They make up about 20% of the genomes of eutherian mammals and have played a major role in shaping genome evolution. Chiroptera has the lowest average genome size among mammalian orders and the only documented case of L1 extinction affecting an entire mammalian family. Herein, L1 activity and extinction are characterized in all families of the order Chiroptera using a method that enriches for the youngest lineages of L1s in the genome. In addition to the previously reported L1 extinction in Pteropodidae, L1 extinction was documented to occur in Mormoops blainvilli, but this event did not affect all species of Mormoopidae. Further, there was no evidence of concordance between the evolution of L1s and their chiropteran host. There were two L1 lineages present before the divergence of all extant bats. Both lineages are extinct in the Pteropodidae. One or the other L1 lineage is extinct in almost all bat families, but Taphozous melanopogon maintains active members of both. Most intriguingly, some families within the Rhinolophoidea retain one active L1 lineage whereas other families retain the other, creating a deep discontinuity between L1 phylogeny and chiropteran phylogeny. These results indicate that there have been numerous losses of active L1 lineages over the history of chiropteran evolution, but that all chiropteran families except Pteropodidae have retained L1 activity.

The solid state structure of an N-heterocyclic borane 1,1,3,3-tetramethyl-1,3λ4,2-diazaborolidin-1-ium chloride is reported. This molecule features numerous Cl⋯H hydrogen bonds. The crystal structure of 1,1,3,3-tetramethyl-1,3λ4,2-diazaborolidin-1-ium chloride shows multiple C–H⋯Cl interactions in the solid state.

The minerals studtite, [UO2(η2-O2)(H2O)2]·2H2O, and metastudtite, [UO2(η2-O2)(H2O)2], are uranyl peroxide minerals that are major oxidative alteration phases of UO2 under conditions of geological storage. The dehydration of studtite has been studied using X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy. XPS of the U 4f region shows small but significant differences between studtite and metastudtite, with the 4f binding energy of studtite being the highest reported for a uranyl mineral studied by this technique. Further information about the changes in the electronic structure was elucidated using U M4-edge high-energy resolution X-ray absorption near-edge structure (HR-XANES) spectroscopy, which directly probes f orbital states. The transition from the 3d to 5fσ* orbital is sensitive to variations in the U═Oaxial bond length and to changes in the bond covalency. We report evidence that the covalence in the uranyl fragment decreases upon dehydration. Photoluminescence spectroscopy ...

Perfluorooctanoic acid (PFOA) is a persistent organic pollutant and widespread in the environment. Three hosts have been synthesized based upon the formation of a fluorous cavity and hydrogen bonding receptors with the aim of extracting PFOA from water into organic solvents. The hosts based upon a calix[4]arene functionalized at the lower rim with amide groups and fluorous ponytails are effective for the quantitative removal of PFOA. Modification to a partial cone or a trisaminoamine framework reduces the conformational rigidity and lowers the extraction efficiency. A comprehensive NMR spectroscopic analysis both in solution and the solid state, along with other characterization techniques, has elucidated the stoichiometry of the host:guest species and the binding constants have been measured. A computational study has given further insight into the binding modes and corroborated the spectroscopic measurements.

A series of complexes [Et4N][Ln(NCS)4(H2O)4] (Ln = Pr, Tb, Dy, Ho, Yb) have been structurally characterized, all showing the same structure, namely a distorted square antiprismatic coordination geometry, and the Ln–O and Ln–N bond lengths following the expected lanthanide contraction. When the counterion is Cs+, a different structural motif is observed and the eight-coordinate complex Cs5[Nd(NCS)8] isolated. The thorium compounds [Me4N]4[Th(NCS)7(NO3)] and [Me4N]4[Th(NCS)6(NO3)2] have been characterized, and high coordination numbers are also observed. Finally, attempts to synthesize a U(III) thiocyanate compound has been unsuccessful; from the reaction mixture, a heterocycle formed by condensation of five MeCN solvent molecules, possibly promoted by U(III), was isolated and structurally characterized. To rationalize the inability to isolate U(III) thiocyanate compounds, thin-layer cyclic voltammetry and IR spectroelectrochemistry have been utilized to explore the cathodic behavior of [Et4N]4[U(NCS)8] and [Et4N][U(NCS)5(bipy)2] along with a related uranyl compound [Et4N]3[UO2(NCS)5]. In all examples, the reduction triggers a rapid dissociation of [NCS]− ions and decomposition. Interestingly, the oxidation chemistry of [Et4N]3[UO2(NCS)5] in the presence of bipy gives the U(IV) compound [Et4N]4[U(NCS)8], an unusual example of a ligand-based oxidation triggering a metal-based reduction. The experimental results have been augmented by a computational investigation, concluding that the U(III)–NCS bond is more ionic than the U(IV)–NCS bond.

A series of 10-[(4-halo-2,6-diisopropylphenyl)imino]phenanthren-9-ones and derivatives of the phenanthrene-9,10-dione ligand have been synthesised and structurally characterised to explore two types of noncovalent interactions, namely the influence of the steric bulk upon the resulting C–H···π and π-stacking interactions and halogen bonding. Selected noncovalent interactions have additionally been analysed by DFT and AIM techniques. No halogen bonding has been observed in these systems, but X lone pair···π, C–H···O=C and C–H···π interactions are the prevalent ones in the halogenated systems. Removal of the steric bulk in N-(2,4,6-trimethylphenyl)-9,10-iminophenanthrenequinone affords different noncovalent interactions, but the C–H···O=C hydrogen bonds are observed. Surprisingly, in N-(2,6-dimethylphenyl)-9,10-iminophenanthrenequinone and N-(phenyl)-9,10-iminophenanthrenequinone these C–H···O=C hydrogen bonds are not observed. However, they are observed in the related 2,6-di-tert-butylphenanthrene-9,10-dione. The π-interactions in dimers extracted from the crystal structures have been analysed by DFT and AIM. Spectroscopic investigations are also presented and these show only small perturbations to the O=C–C=N fragment.

The solid state structure of 1,1,1,2,2,3,3-heptachloropropane is reported. This molecule features numerous type I and type II Cl⋯Cl interactions in the solid state as well as Cl⋯H hydrogen bonds. A Hirshfeld surface analysis is also presented. The crystal structure of 1,1,1,2,2,3,3-heptachloropropane shows type I and type II Cl⋯Cl interactions in the solid state.

A series of R2Sn (R = Me, Ph) complexes of the Schiff’s base salicylaldehyde acyldihydrazone with a methylene spacer of variable length have been structurally characterized in order to explore the prevalence of Sn···O noncovalent interactions. Structural studies show that these can exist, with the shortest Sn···O distance of 3.480(2) A in this library of compounds, significantly shorter than the sum of the van der Waals radii (3.92 A). Crystallographic studies also show that steric effects are important, and these interactions are seen only for compounds with Me2Sn while they are not observed for Ph2Sn. However, this is not simply a steric effect, and C–H···O interactions can compete with these Sn···O interactions. A computational study, in combination with the quantum theory of atoms in molecules, shows that these interactions are mostly electrostatic in origin with little evidence of covalency.

The extent and nature of covalency in actinide complexes is an important and complex question. There are two main mechanisms of covalency, namely overlap of orbitals or degeneracy of the energies of the ligand and actinide metal, and computational approaches can play a significant part in rationalising the relative importance of each. In this work, we use a suite of computational approaches including Natural Bond Orbitals (NBO), Quantum Theory of Atoms in Molecules (QTAIM) and Interacting Quantum Atoms (IQA) to probe these effects in [EUE]2+ (E = O, S, Se, Te) and [UE2(H2O)5]2+ compounds. All methods indicate increased bond order and reduced charge separation on descending the group. Donation from filled np orbitals on E into formally empty orbitals on U is evident, with 5f and 6d orbitals the most populated. NBO analysis quantifies orbital interactions, finding energy separation is largest for E = O, while for E = Te the atomic orbitals are almost degenerate. However, NBO and IQA data suggests that although overlap is greater for heavier chalcogens, stabilisation due to covalency is greatest for E = O. Thus, for the heavier chalcogens we find that covalency is driven by near-degeneracy of orbitals involved, which does not stabilise the complexes to the same extent as overlap-driven covalency in uranyl. In the hydrated ions the same trends are broadly reproduced, albeit with more stabilisation and a lower HOMO–LUMO gap. The structure and stability of the [OUS]2+ ion is also examined, showing evidence for an inverse trans-influence. Finally bending of the [US2(H2O)5]2+ ion has been examined, suggesting a possible meta-stable cis-form.

Herein, a multi-technique study was performed to reveal the elemental speciation and microphase composition in altered granitic rock collected from the Krunkelbach Valley uranium (U) deposit area near an abandoned U mine, Black Forest, Southern Germany., RSC Advances (2020)

Computational modeling is an important aspect of the research on nuclear waste materials. In particular, atomistic simulations, when used complementary to experimental efforts, contribute to the scientific basis of safety case for nuclear waste repositories. Here we discuss the state-of-the-art and perspectives of atomistic modeling for nuclear waste management on a few cases of successful synergy of atomistic simulations and experiments. In particular, we discuss here: (1) the potential of atomistic simulations to investigate the uranium oxidation state in mixed valence uranium oxides and (2) the ability of cementitious barrier materials to retain radionuclides such as 226Ra and 90Sr, and of studtite/metastudtite secondary peroxide phases to incorporate actinides such as Np and Am. The new contribution we make here is the computation of the incorporation of Sr by C-S-H (calcium silicate hydrate) phases., MRS Advances (2020)

Neptunium(V) and uranium(VI) are precipitated from an aqueous potassium–sodium-containing carbonate-rich solution, and the solid phases are investigated. U/Np M4,5-edge high-energy resolution X-ray absorption near edge structure (HR-XANES) spectroscopy and Np 3d4f resonant inelastic X-ray scattering (3d4f RIXS) are applied in combination with thermodynamic calculations, U/Np L3-edge XANES, and extended X-ray absorption fine structure (EXAFS) studies to analyze the local atomic coordination and oxidation states of uranium and neptunium. The XANES/HR-XANES analyses are supported by ab initio quantum-chemical computations with the finite difference method near-edge structure code (FDMNES). The solid precipitates are also investigated with powder X-ray diffraction, scanning electron microscopy–energy dispersive X-ray spectroscopy, and Raman spectroscopy. The results strongly suggest that K[NpVO2CO3](cr), K3[NpVO2(CO3)2](cr), and K3Na[UVIO2(CO3)3](cr) are the predominant neptunium and uranium solid phases form...

The extent and nature of covalency in actinide complexes is an important and complex question. There are two main mechanisms of covalency, namely overlap of orbitals or degeneracy of the energies of the ligand and actinide metal, and computational approaches can play a significant part in rationalising the relative importance of each. In this work, we use a suite of computational approaches including Natural Bond Orbitals (NBO), Quantum Theory of Atoms in Molecules (QTAIM) and Interacting Quantum Atoms (IQA) to probe these effects in [E[double bond, length as m-dash]U[double bond, length as m-dash]E]

Studtite, [UO2(η2-O2)(H2O)2]·2H2O, and metastudtite, [UO2(η2-O2)(H2O)2], are important phase alterations of UO2 in a spent nuclear fuel repository and have previously been shown to react with Np(V). In this work we extend the study to Am(V) on a tracer scale and show spectroscopic evidence that the Am is incorporated into the structure of studtite as Am(III). A computational study on the possible mechanisms for the incorporation of Np and Am shows that protonation of the -yl oxygen is the favoured route and the calculated incorporation energies are large and positive. The results suggest that Am is less favoured compared to Np but energetically more favoured to incorporate both actinide ions into metastudtite rather than studtite. Finally, we have shown that once incorporated, Am readily leaches into water but spectroscopic measurements suggest subtle changes in the structure of studtite.

The synthesis of two types of phosphine ligands that feature perfluorinated ponytails is reported. A bidentate (RfCH2CH2)2PCH2CH2P(CH2CH2Rf)2 (Rf = CF3(CF2)n; n = 5, 7) and an alkoxyphosphine made by ring opening a fluorous epoxide, RfCH2CH(OH)CH2PR2 (Rf = CF3(CF2)7), have been prepared and spectroscopically characterised. The electronic effects of the fluorous chains have been elucidated from either the 1JPt–P or 1JP–Se coupling constants in Pt(II) or phosphine selenide compounds. Whilst the bidentate phosphines do not give stable or active Pd catalysts, the hybrid ligand does allow Susuki, Heck and Sonogashira catalysis to be demonstrated with low catalyst loadings and good turnovers. Whilst a fluorous extraction methodology does not give good performance, the ligand can be adsorbed onto Teflon tape and for the Suzuki cross coupling reaction the catalytic system can be run 6 times before activity drops and this has been traced to oxidation of the ligand. Additionally the crystal structure of the hybrid phosphine oxide is reported and the non-covalent interactions discussed.

Oxidation of Cs4[U(NCS)8] in different solvents results in two mixed-valent uranium compounds. Spectroscopic, magnetic and computational data support a unique [UIVUVUIV][UVI] oxidation state assignment in [U(DMF)8(μ-O)U(NCS)5(μ-O)U(DMF)7(NCS)][UO2(NCS)5].

Although coloniality is widespread among mammals, it is still not clear what factors influence composition of social groups. As animals need to adapt to multiple habitat and environmental conditions throughout their range, variation in group composition should be influenced by adaptive adjustment to different ecological factors. Relevant to anthropogenic disturbance, increased habitat modification by humans can alter species’ presence, density, and population structure. Therefore, it is important to understand the consequences of changes to landscape composition, in particular how habitat modification affects social structure of group‐forming organisms. Here, we combine information on roosting associations with genetic structure of Peter's tent‐roosting bats, Uroderma bilobatum to address how different habitat characteristics at different scales affect structure of social groups. By dividing analyses by age and sex, we determined that genetic structure was greater for adult females than adult males or offspring. Habitat variables explained 80% of the variation in group relatedness (mainly influenced by female relatedness) with roost characteristics contributing the most explained variation. This suggests that females using roosts of specific characteristics exhibit higher relatedness and seem to be philopatric. These females mate with more males than do more labile female groups. Results describe ecological and microevolutionary processes, which affect relatedness and social structure; findings are highly relevant to species distributions in both natural and human‐modified environments.

Phyllostomidae (New World leaf-nosed bats), the second most speciose chiropteran family, is one of the best-known and wellstudied chiropteran groups. Due to the ecological and morphological diversity of this family, comparative studies of phyllostomids abound in the literature, and numerous systematic and phylogenetic analyses have been published. Unfortunately, many of these studies have reached different conclusions concerning phyllostomid relationships, and have proposed different classification schemes. This has led to confusion, and highlighted the need for a well-supported and stable classification of the family, particularly at the level of subfamilies and tribes, areas of the greatest controversy. The goal of this paper is to provide morphological diagnoses of higher-level taxa (subtribes, tribes, and subfamilies). Herein we provide morphological diagnoses for 11 subfamilies (Macrotinae, Micronycterinae, Desmodontinae, Lonchorhininae, Phyllostominae, Glyphonycterinae, Glossophaginae, Lonchophyllin...

The family Phyllostomidae is recognized as representing the most extensive radiation known in any mammalian family. Creating a Linnaean classification for this clade has been difficult and controversial. In two companion papers, we here propose a revised classification drawing on the strengths of genetic and morphological data and reflecting current ideas regarding phylogenetic relationships within this monophyletic clade. We recognize 11 subfamilies (Macrotinae, Micronycterinae, Desmodontinae, Phyllostominae, Glossophaginae, Lonchorhininae, Lonchophyllinae, Glyphonycterinae, Carolliinae, Rhinophyllinae, and Stenodermatinae), 12 tribes (Diphyllini, Desmodontini, Macrophyllini, Phyllostomini, Vampyrini, Glossophagnini, Brachyphyllini, Choeronycterini, Lonchophyllini, Hsunycterini, Sturnirini, and Stenodermatini), and nine subtribes (Brachyphyllina, Phyllonycterina, Anourina, Choeronycterina, Vampyressina, Enchisthenina, Ectophyllina, Artibeina, and Stenodermatina). The proposed arrangement avoids non-monop...

We present a comparative molecular cytogenetic investigation of six emballonurid species using chromosome banding and cross-species chromosome painting with probes from Myotis myotis, supplemented by selected probes from human, tree shrew, and lemur. The main differences between the 2n = 42 Taphozous karyotype and the 2n = 44 chromosomal complement of Saccolaimus can be explained by one Robertsonian fusion, one type-b, and one type-c whole arm reciprocal translocation. The 2n = 24 karyotype of Emballonura is highly derived by splitting of 11 of the 25 chiropteran evolutionarily conserved units resulting in a total number of 36 segments. In contrast to the presence of several autapomorphies in the karyotypes of studied species from both subfamilies, no cytogenetic synapomorphy uniting Taphozoinae and Emballonurinae was found.

Populations that have historically been isolated from each other are expected to differ in some heritable features. This divergence could be due to drift (and other mechanisms of neutral evolution) or differential adaptation of populations to local conditions. Discriminating between these two evolutionary trajectories can be difficult, but when possible, such data provides critical insight into the evolutionary history of a species. Here, we examine the patterns of geographic variation of two contact signals regularly produced by disc-winged bats, Thyroptera tricolor, and discuss possible processes leading to the observed patterns of differentiation. We compared allopatric populations separated by an elevational barrier, and estimated genetic distance using nuclear microsatellite loci. Our findings revealed that the mountain ridge is permeable to gene flow. Acoustic divergence was significantly explained by genetic and spatial factors, supporting the notion that stochastic factors are the main drivers of signal divergence. Yet, we found different patterns of geographic variation between the two types of calls. We examine how this variability in the patterns of acoustic divergence may suggest distinct modes of signal transmission within and between populations (i.e., social vs genetic transmission). This work provides further support of the role of random change shaping communication systems in mammals, and highlights the importance of studying multiple elements of a species repertoire to evaluate the underlying processes driving signal evolution. Despite increasing interest in studying patterns of acoustic divergence, the relative contribution of adaptive and stochastic processes underlying variation of acoustic signals remain poorly understood, particularly in mammals. Our study examines signal divergence in Spix’s disc-winged bats, Thyoptera tricolor, with the goal of understanding the underlying processes driving signal evolution. Specifically, we studied whether the patterns of geographic variation of two social signals regularly emitted by T. tricolor are congruent with patterns of genetic distance among populations separated by a geographic barrier. We demonstrate that genetic and spatial distance explains acoustic variation, which points to stochastic processes as major drivers of signal divergence in T. tricolor. Notably, we found that the patterns of geographic variation differ between the two types of calls studied. We suggest that this variation results from distinct modes of vocal transmission within populations. Comparison of different signal types provides additional insight of social pressures shaping call design.

We report a set of theoretical calculations designed to examine the potential of model uranyl complexes to participate in hydrogen- and halogen-bonding. Potential energy scans for the interaction of [UO2Cl2(H2O)3] and [UO2(NCSe)2(H2O)3] with a single water molecule demonstrate that uranyl is a weak hydrogen bond acceptor, but that equatorially coordinated water is a strong hydrogen bond donor. These predictions are supported by a survey of contacts reported in the Cambridge Structural Database. At the minima of each scan, we show that the interaction energy is only weakly dependent on the choice of the theoretical method, with standard density functional theory methods comparing well with coupled-cluster, MP2 and double-hybrid DFT predictions. Geometry optimisation of a 1 : 1 uranyl : water complex results in a cyclic structure, in which vibrational frequencies, atoms-in-molecules and natural bond orbital analysis support the weakness of U-Oyl as an acceptor. The origin of this behaviour is traced to the electronic structure of uranyl, and in particular covalency in the U-Oyl bonds resulting from donation into formally empty 5f and 6d orbitals on U.

A series of uranyl thiocyanate and selenocyanate of the type [R4N]3[UO2(NCS)5] (R4 = nBu4, Me3Bz, Et3Bz), [Ph4P][UO2(NCS)3(NO3)] and [R4N]3[UO2(NCSe)5] (R4 = Me4, nPr4, Et3Bz) have been prepared and structurally characterized. The resulting noncovalent interactions have been examined and compared to other examples in the literature. The nature of these interactions is determined by the cation so that when the alkyl groups are small, chalcogenide···chalcogenide interactions are present, but this “switches off” when R = nPr and charge assisted U═O···H–C and S(e)···H–C hydrogen bonding remain the dominant interaction. Increasing the size of the chain to nBu results in only S···H–C interactions. The spectroscopic implications of these chalcogenide interactions have been explored in the vibrational and photophysical properties of the series [R4N]3[UO2(NCS)5] (R4 = Me4, Et4, nPr4, nBu4, Me3Bz, Et3Bz), [R4N]3[UO2(NCSe)5] (R4 = Me4, nPr4, Et3Bz) and [Et4N]4[UO2(NCSe)5][NCSe]. The data suggest that U═O···H–C interactions are weak and do not perturb the uranyl moiety. While the chalcogenide interactions do not influence the photophysical properties, a coupling of the U═O and δ(NCS) or δ(NCSe) vibrational modes is observed in the 77 K solid state emission spectra. A theoretical examination of representative examples of Se···Se, C–H···Se, and C–H···O═U by molecular electrostatic potentials and NBO and AIM methodologies gives a deeper understanding of these weak interactions. C–H···Se are individually weak but C–H···O═U interactions are even weaker, supporting the idea that the -yl oxo’s are weak Lewis bases. An Atoms in Molecules study suggests that the chalcogenide interaction is similar to lone pair···π or fluorine···fluorine interactions. An oxidation of the NCS ligands to form [(UO2)(SO4)2(H2O)4]·3H2O was also noted.

The minerals studtite, [UO

The use of laser sources can expand the range of applications of photochemical surface functionalization strategies, increasing reaction rate and sample throughput. However, high irradiances can result in thermal effects and/or changes in the mechanism of photoinduced reactions. In this work we report on the use of a pulsed UV laser source for the modification of carbon surfaces using fluorinated terminal alkenes. A perfluorinated alkene, 1H,1H,2H-perfluoro-dec-1-ene (PFD), was used to modify amorphous carbon surfaces using a pulsed excimer laser (248 nm). The rate and yield of photoinduced PFD chemisorption was measured using Infrared Reflectance Absorption Spectroscopy (IRRAS) and compared to that obtained using a continuous lamp source. Quartz Crystal Microbalance (QCM) measurements were also used to obtain quantitative estimates of surface coverage and quantum yields. We found that, under the experimental conditions investigated, PFD chemisorption rates at bare carbon are proportional to the rate of incident photons. Simulations indicated that thermal effects of laser irradiation are expected to be minor, thus supporting the conclusion that the pulsed source can be used to accelerate the reaction rate without leading to changes in reaction mechanism. However, we observed that the limiting chemisorption yield was ∼30% higher for the laser source. We propose that this difference is due to photochemical formation of multilayers, a reaction that is slower than chemisorption at bare carbon, but that becomes evident when very high total fluence is applied via pulsed sources. Finally, we investigated the influence of reaction conditions on the ability of fluorinated carbon surfaces obtained via laser- and lamp-driven reactions to adsorb and capture fluorinated ligands via non-covalent fluorous–fluorous interactions.

The reaction of a number of uranyl minerals of the (oxy)hydroxide, phosphate and carbonate types with Eu(iii), as a surrogate for Am(iii), have been investigated. A photoluminescence study shows that Eu(iii) can interact with the uranyl minerals Ca[(UO2)6(O)4(OH)6]·8H2O (becquerelite) and A[UO2(CO3)3]·xH2O (A/x = K3Na/1, grimselite; CaNa2/6, andersonite; and Ca2/11, liebigite). For the minerals [(UO2)8(O)2(OH)12]·12H2O (schoepite), K2[(UO2)6(O)4(OH)6]·7H2O (compreignacite), A[(UO2)2(PO4)2]·8H2O (A = Ca, meta-autunite; Cu, meta-torbernite) and Cu[(UO2)2(SiO3OH)2]·6H2O (cuprosklodowskite) no Eu(iii) emission was observed, indicating no incorporation into, or sorption onto the structure. In the examples with Eu(3+) incorporation, sensitized emission is seen and the lifetimes, hydration numbers and quantum yields have been determined. Time Resolved Laser Induced Fluroescence Spectroscpoy (TRLFS) at 10 K have also been measured and the resolution enhancements at these temperatures allow further information to be derived on the sites of Eu(iii) incorporation. Infrared and Raman spectra are recorded, and SEM analysis show significant morphology changes and the substitution of particularly Ca(2+) by Eu(3+) ions. Therefore, Eu(3+) can substitute Ca(2+) in the interlayers of becquerelite and liebigite and in the structure of andersonite, whilst in grimselite only sodium is exchanged. These results have guided an investigation into the reactions with (241)Am on a tracer scale and results from gamma-spectrometry show that becquerelite, andersonite, grimselite, liebigite and compreignacite can include americium in the structure. Shifts in the U[double bond, length as m-dash]O and C-O Raman active bands are similar to that observed in the Eu(iii) analogues and Am(iii) photoluminescence measurements are also reported on these phases; the Am(3+) ion quenches the emission from the uranyl ion.

In this paper we study the stability of a phase-locked loop (PLL) in the presence of noise. We represent the noise as Brownian motion and model the circuit as a nonlinear stochastic differential equation, with the noise lumped at the phase detector input. We show that for the PLL, the theory of asymptotics of singular diffusions can be applied and we use this theory to develop a new figure of merit which we call a stability margin. The stability margin provides easily computable bounds on the acceptable noise levels for which stability is guaranteed. Through simulation, we show that such a sufficient bound provides a realistic prediction for PLL stability.

The solid-state structures of CF3(CF2)5CH2CO2H and a fluorous triazole are reported, both of which display a wide variety and large number of noncovalent interactions in their packing. The solid-state structure of CF3(CF2)5CH2CO2H is stabilized by multiple F···F contacts but only one C–H···F–C interaction, as well as O–H···O and C–H···O hydrogen bonds. In contrast to other reported structures, the torsion angles in the fluorous chain are close to 180°, which means that the fluorine atoms are eclipsed. A DFT study of the interactions in both compounds show that F···F interactions, along with stacking and C–H···F and C–H···O contacts, are individually weakly energetically stabilizing, but collectively, they can give rise to interaction energies of up to 13 kcal mol–1. A topological approach to the interactions using atoms-in-molecules (AIM) theory reveals that there are bond critical points between the C–F···F–C interactions as well as C–F···H–C interactions that are not recognized when using only the van d...

The amino acid [1-(aminomethyl)cyclohexyl]acetic acid was reacted with 2-hydroxynaphthaldehyde to produce the Schiff base ligand [1-({[(Z)-(2-hydroxynaphthalen-1-yl)methylidene]amino}methyl)cyclohexyl]acetic acid (H-HMAC) which was fully characterized spectroscopically and by single crystal diffraction. It was reacted with metal ions to produce compounds with composition [M(HMAC)2] [M = Co(II), Ni(II), Cu(II) and Zn(II)], which were characterized spectroscopically, with distorted tetragonal geometries assigned based on spectroscopic and B3LYP theoretical studies. All synthesized compounds were studied for their thermal stabilities under static air. The coordination compounds were also screened for their free radical scavenging properties using DPPH free radicals and xanthine oxidase inhibitory activities. Only the zinc complex was found to be an inhibitor of the enzymatic activity with IC50 = 0.7 ± 0.01 μM ± SEM better than the standard reference drug used. The inhibitory activity was structurally rationalized by carrying out molecular modeling studies using the auto dock program.

Author(s): Cook, JA; Greiman, SE; Agosta, SJ; Anderson, RP; Arbogast, BS; Baker, RJ; Boeger, W; Bradley, RD; Brooks, DR; Cole, R; Demboski, JR; Dobson, AP; Dunnum, JL; Eckerlin, RP; Esselstyn, J; Galbreath, KE; Hawdon, J; Hoekstra, HE; Kutz, SJ; Light, JE; Olson, LE; Patterson, BD; Patton, JL; Phillips, AJ; Rickart, E; Rogers, DS; Siddall, ME; Tkach, VV; Hoberg, EP

The perovskite La0.15Sm0.35Sr0.08Ba0.42FeO3 − δ has been prepared by the glycine nitrate (GNC) route, varying the fuel/oxidizer ratio (glycine/nitrate, G/N = 1 and 2) and cooling rate (slow cooling and air-quenched), in order to study the influence of sample preparation on the materials' properties, in the context of their application as a cathode material for SOFCs. For this, the performance of the prepared mixed ion and electron conducting perovskite oxides is dictated by their structure, oxygen stoichiometry (3 − δ), chemical composition and thermal expansion properties. High-resolution Synchrotron X-ray powder diffraction patterns were collected at room temperature and at 700 and 800 °C. It was found that the materials had a cubic crystal structure at these temperatures. As expected, 3 − δ decreased as temperature increased, and was slightly smaller for the quenched sample. Higher electrical conductivity values were obtained for the sample with G/N = 1 (air-quenched) in the cooling rate. At 700 and 800 °C the cathode synthesized with G/N = 1 and air-quenched showed the smallest polarization resistance values in impedance spectroscopy studies. Therefore, the physicochemical and electrochemical characterization clearly demonstrated the influence of the synthetic conditions on the cathode performance., This research has been funded by the Ministerio de Economía, Industria y Competitividad (MAT2016-76739-R (AEI/FEDER, UE) and MAT2015-86078-R), and Departamento de Educación of the Basque Government (IT-630-13). The authors thank SGIker of UPV/EHU for technical and personnel support. This work was benefited from the BL04-MSPD beamline at ALBA. The authors thank Dr. Francois Fauth of the Experiments Division of ALBA for his assistance in situ synchrotron measurements. K. Vidal thanks UPV/EHU for funding.

Currently, the effects of chronic, continuous low dose environmental irradiation on the mitochondrial genome of resident small mammals are unknown. Using the bank vole (Myodes glareolus) as a model system, we tested the hypothesis that approximately 50 generations of exposure to the Chernobyl environment has significantly altered genetic diversity of the mitochondrial genome. Using deep sequencing, we compared mitochondrial genomes from 131 individuals from reference sites with radioactive contamination comparable to that present in northern Ukraine before the 26 April 1986 meltdown, to populations where substantial fallout was deposited following the nuclear accident. Population genetic variables revealed significant differences among populations from contaminated and uncontaminated localities. Therefore, we rejected the null hypothesis of no significant genetic effect from 50 generations of exposure to the environment created by the Chernobyl meltdown. Samples from contaminated localities exhibited significantly higher numbers of haplotypes and polymorphic loci, elevated genetic diversity, and a significantly higher average number of substitutions per site across mitochondrial gene regions. Observed genetic variation was dominated by synonymous mutations, which may indicate a history of purify selection against nonsynonymous or insertion/deletion mutations. These significant differences were not attributable to sample size artifacts. The observed increase in mitochondrial genomic diversity in voles from radioactive sites is consistent with the possibility that chronic, continuous irradiation resulting from the Chernobyl disaster has produced an accelerated mutation rate in this species over the last 25 years. Our results, being the first to demonstrate this phenomenon in a wild mammalian species, are important for understanding genetic consequences of exposure to low‐dose radiation sources.

The rapid diversification of Myotis bats into more than 100 species is one of the most extensive mammalian radiations available for study. Efforts to understand relationships within Myotis have primarily utilized mitochondrial markers and trees inferred from nuclear markers lacked resolution. Our current understanding of relationships within Myotis is therefore biased towards a set of phylogenetic markers that may not reflect the history of the nuclear genome. To resolve this, we sequenced the full mitochondrial genomes of 37 representative Myotis, primarily from the New World, in conjunction with targeted sequencing of 3,648 ultraconserved elements (UCEs). We inferred the phylogeny and explored the effects of concatenation and summary phylogenetic methods, as well as combinations of markers based on informativeness or levels of missing data, on our results. Of the 294 phylogenies generated from the nuclear UCE data, all are significantly different from phylogenies inferred using mitochondrial genomes. Even within the nuclear data, quartet frequencies indicate that around half of all UCE loci conflict with the estimated species tree. Several factors can drive such conflict, including incomplete lineage sorting, introgressive hybridization, or even phylogenetic error. Despite the degree of discordance between nuclear UCE loci and the mitochondrial genome and among UCE loci themselves, the most common nuclear topology is recovered in one quarter of all analyses with strong nodal support. Based on these results, we re-examine the evolutionary history of Myotis to better understand the phenomena driving their unique nuclear, mitochondrial, and biogeographic histories.