Ark or park: the need to predict relative effectiveness of ex situ and in situ conservation before attempting captive breeding

1. When species face extinction, captive breeding may be appropriate. However, captive breeding may be unsuccessful, while reducing motivation and resources for in situ conservation and impacting wild source populations. Despite such risks, decisions are generally taken without rigorous evaluation. We develop an individual-based, stochastic population model to evaluate the potential effectiveness of captive-breeding and release programmes, illustrated by the Critically Endangered Ardeotis nigriceps Vigors great Indian bustard. 2. The model was parameterized from a comprehensive review of captive breeding and wild demography of large bustards. To handle uncertainty in the standards of captive-breeding performance that may be achieved we explored four scenarios of programme quality: ‘full-range’ (parameters sampled across the observed range), ‘below-average’, ‘above-average’ and ‘best possible’ (performance observed in exemplary breeding programmes). Results are evaluated examining i) the probability of captive population extirpation within 50 years and ii) numbers of adult females subsequently established in the wild following release, compared to an alternative strategy of in situ conservation without attempting captive breeding. 3. Successful implementation of captive breeding, involving permanent retention of 20 breeding females and release of surplus juveniles, required collection of many wild eggs and consistent ‘best possible’ performance across all aspects of the programme. Under ‘full-range’ and ‘above-average’ scenarios captive population extirpation probabilities were 73–88% % and 23‒51%% respectively, depending on egg collection rates. 4. Although most (73‒92%) ‘best possible’ programmes supported releases, re-establishment of free-living adults also required effective in situ conservation. Incremental implementation of effective conservation measures over the initial 10 years resulted in more free-living adults within 35 years if eggs were left in the wild without attempting captive breeding. 5. Synthesis and applications. For the great Indian bustard Ardeotis nigriceps, rapid implementation of in situ conservation offers a better chance to avoid extinction than captive breeding. Demographic modelling should be used to examine whether captive breeding is likely to bring net benefits to conservation programmes

Synthesis, isotopic enrichment and solid-state NMR characterization of zeolites derived from the assembly, disassembly, organisation, reassembly process

We would like to thank the ERC (EU FP7 Consolidator Grant 614290 “EXONMR”), the Leverhulme Trust (IN-2012-094), and EPSRC (EP/K025112/1, EP/L014475/1, and EP/M506631/1 (for GPMB)). S.E.A. would like to thank the Royal Society and the Wolfson Foundation for a merit award. The research data (and/or materials) supporting this publication can be accessed at DOI: 10.17630/d66d1146-5892-4f14-8e41-dfc075a8cd91.The great utility and importance of zeolites in fields as diverse as industrial catalysis and medicine has driven considerable interest in the ability to target new framework types with novel properties and applications. The recently introduced and unconventional assembly, disassembly, organization, reassembly (ADOR) method represents one exciting new approach to obtain solids with targeted structures by selectively disassembling preprepared hydrolytically unstable frameworks and then reassembling the resulting products to form materials with new topologies. However, the hydrolytic mechanisms underlying such a powerful synthetic method are not understood in detail, requiring further investigation of the kinetic behavior and the outcome of reactions under differing conditions. In this work, we report the optimized ADOR synthesis, and subsequent solid-state characterization, of 17O- and doubly 17O- and 29Si-enriched UTL-derived zeolites, by synthesis of 29Si-enriched starting Ge-UTL frameworks and incorporation of 17O from 17O-enriched water during hydrolysis. 17O and 29Si NMR experiments are able to demonstrate that the hydrolysis and rearrangement process occurs over a much longer time scale than seen by diffraction. The observation of unexpectedly high levels of 17O in the bulk zeolitic layers, rather than being confined only to the interlayer spacing, reveals a much more extensive hydrolytic rearrangement than previously thought. This work sheds new light on the role played by water in the ADOR process and provides insight into the detailed mechanism of the structural changes involved.Publisher PDFPeer reviewe

Sterically restricted tin phosphines, stabilized by weak intramolecular donor-acceptor interactions

Funding: Engineering and Physical Sciences Research Council (EPSRC)Four related sterically restricted pen-substituted acenaphthenes have been prepared containing mixed tin phosphorus moieties in the proximal 5,6-positions (Acenap[SnR3][(PPr2)-Pr-i]; Acenap = acenaphthene-5,6-diyl; R-3 = Ph-3 (1), Ph2Cl (2), Me2Cl (3), Bu2Cl (4)). The degree of intramolecular P-Sn bonding within the series was investigated by X-ray crystallography, solution and solid-state NMR spectroscopy, and density functional theory (DFT/B3LYP/SBKJC/PCM) calculations. All members of the series adopt a conformation such that the phosphorus lone pair is located directly opposite the tin center, promoting an intramolecular donor acceptor P -> Sn type interaction. The extent of covalent bonding between Sn and P is found to be much greater in triorganotin chlorides 2-4 in comparison with the triphenyl derivative 1. Coordination of a highly electronegative chlorine atom naturally increases the Lewis acidity of the tin center, enhancing the Ip(P)-sigma*(Sn-Y) donor acceptor 3c-4e type interaction, as indicated by conspicuously short Sn-P peri distances and significant (1)J(P-31,Sn-119) spin spin coupling constants (SSCCs) in the range 740-754 Hz. Evidence supporting the presence of this interaction was also found in solid-state NMR spectra of some of the compounds which exhibit an indirect spin spin coupling on the same order of magnitude as observed in solution. DFT calculations confirm the increased covalent bonding between P and Sn in 2-4, with notable WBIs of ca. 0.35 obtained, in comparison to 0.1 in 1.PostprintPeer reviewe

Synthesis and polymorphism of mixed aluminium-gallium oxides

DSC is grateful to the EPSRC for award of an industrial CASE studentship, partly funded by Johnson Matthey plc. SEA, DMD and JEH thank the ERC (EU FP7 Consolidator Grant 614290 “EXONMR”) for funding. SEA would also like to thank the Royal Society and Wolfson Foundation for a merit award.The synthesis of a new solidsolution of the oxyhydroxide Ga5–xAlxO7(OH) isinvestigated via solvothermalreaction between gallium acetylacetonate and aluminium isopropoxide in1,4-butanediol at 240 °C. A limited compositional range 0 ≤ x ≤ 1.5 is produced, with the hexagonalunit cell parameters refined from powder X-ray diffraction (XRD) showing alinear contraction in unit cell volume with increasing Al content. Solid-state 27Aland 71Ga NMR spectroscopy show a strong preference for Ga to occupythe tetrahedral sites and Al to occupy the octahedral sites. Using isopropanolas the solvent, g-Ga2–xAlxO3defect spinel solid solutions with x ≤ 1.8 can be prepared at 240 °C in24 hours. These materials are nanocrystalline, as evidenced by their broaddiffraction profiles, but the refined cubic lattice parameter shows a linearrelationship with the Ga:Al content and solid-state NMR spectroscopy again showsa preference for Al to occupy the octahedral sites. Thermal decomposition ofthe Ga5–xAlxO7(OH)occurs via poorly ordered materials that resemble e-Ga2–xAlxO3and k-Ga2–xAlxO3,but g-Ga2–xAlxO3transforms above 750 °C to monoclinic b-Ga2–xAlxO3for 0 ≤ x ≤ 1.3 and to hexagonal a-Ga2–xAlxO3for x = 1.8, with intermediate compositions 1.3 < x < 1.8 giving mixturesof the aand b polymorphs.Solid-state NMR spectroscopy shows only the expected octahedral Al for a-Ga2–xAlxO3and, for b-Ga2–xAlxO3,the ~1:2 ratio of tetrahedral:octahedral Al is in good agreement with Rietveldanalysis of the average structures against powder XRD data. Relative energiescalculated by periodic density functional theory (DFT) confirm that there is a~5.2 kJ mol–1 penalty for tetrahedral rather than octahedral Al inGa5–xAlxO7(OH), whereas this penalty is muchlower (~2.0 kJ mol–1) for b-Ga2–xAlxO3,in good qualitative agreement with the experimental NMR spectra.PostprintPeer reviewe

Phase distribution, composition and disorder in Y2(Hf,Sn)2O7 ceramics : insights from solid-state NMR spectroscopy and first-principles calculations

The authors would like to thank the ERC (EU FP7 Consolidator Grant 614290 “‘EXONMR’”), and EPSRC for support for SS and ASG (EP/L005581/1). SEA would like to thank the Royal Society and Wolfson Foundation for a merit award. We acknowledge support from the Collaborative Computational Project on NMR Crystallography CCP-NC funded by EPSRC (EP/M022501/1).A NMR crystallographic approach, combining 89Y, 119Sn and 17O NMR spectroscopy with X-ray diffraction and first-principles calculations has been used investigate the number and type of phases present, and the local structure and disorder in Y2Hf2–xSnxO7 ceramics. Although a phase change is predicted with increasing Hf content, NMR spectra clearly show the presence of a significant two-phase region, with a Sn-rich pyrochlore and relatively Hf-rich defect fluorite phase co-existing for much of the compositional series. A single-phase pyrochlore is found only for the Sn end member, and a single defect fluorite phase only for x = 0 to 0.2. A solid-solution limit of ~10% is seen for the substitution of Hf into Y2Sn2O7, although no evidence is seen for any cation ordering or antisite disorder in this phase. In the defect fluorite phase there is preferential ordering of oxygen vacancies around Sn, which is only ever seen in a six-coordinate environment. The remaining vacancies are more likely to be associated with Hf than with Y, although this distinction is less apparent at higher Sn concentrations. To acquire 17O NMR spectra samples were post-synthetically exchanged with 17O2(g), although high temperatures (> 900 ºC) were required to ensure uniform enrichment of different chemical species. although these 17O NMR spectra confirm the formation of mixed-metal materials and the presence of two phases, more quantitative analysis is hindered by the overlap of signals from pyrochlore and defect fluorite phases. In all cases, DFT calculations play a vital role in the interpretation and assignment of the NMR spectra, and in understanding the local structure and disorder in these complex multi-phase materials.PostprintPostprintPeer reviewe

In situ solid-state NMR and XRD studies of the ADOR process and the unusual structure of zeolite IPC-6

R.E.M. and M.N. thank the Royal Society and the E.P.S.R.C. (Grants EP/L014475/1, EP/K025112/1 and EP/K005499/1) for funding work in this area. R.E.M. and J.Č. acknowledge the Czech Science Foundation for the project P106/12/G015 and OP VVV "Excellent Research Teams", project No. CZ.02.1.01/0.0/0.0/15_003/0000417 - CUCAM. S.E.A. would like to thank the ERC (EU FP7 Consolidator Grant 614290 “EXONMR”) and the Royal Society and Wolfson Foundation for a merit award. The UK 850 MHz solid-state NMR Facility used in this research was funded by EPSRC and BBSRC (contract reference PR140003), as well as the University of Warwick including via part funding through Birmingham Science City Advanced Materials Projects 1 and 2 supported by Advantage West Midlands (AWM) and the European Regional Development Fund (ERDF). W.A.S. and D.S.W. acknowledge the Research Council of Norway and NOTUR are acknowledged for providing the computer time at the Norwegian supercomputer facilities (under the project number NN2875k).The assembly–disassembly–organization–reassembly (ADOR) mechanism is a recent method for preparing inorganic framework materials and, in particular, zeolites. This flexible approach has enabled the synthesis of isoreticular families of zeolites with unprecedented continuous control over porosity, and the design and preparation of materials that would have been difficult—or even impossible—to obtain using traditional hydrothermal techniques. Applying the ADOR process to a parent zeolite with the UTL framework topology, for example, has led to six previously unknown zeolites (named IPC-n, where n = 2, 4, 6, 7, 9 and 10). To realize the full potential of the ADOR method, however, a further understanding of the complex mechanism at play is needed. Here, we probe the disassembly, organization and reassembly steps of the ADOR process through a combination of in situ solid-state NMR spectroscopy and powder X-ray diffraction experiments. We further use the insight gained to explain the formation of the unusual structure of zeolite IPC-6.PostprintPeer reviewe

Determining the surface structure of silicated alumina catalysts via isotopic enrichment and dynamic nuclear polarization surface-enhanced NMR spectroscopy

We would like to thank SASOL and EPSRC (EP/L505079/1) for studentship funding for AGMR. SEA would also like to thank the Royal Society and Wolfson Foundation for a merit award. PBW would like to thank the Royal Society for the award of an Industry Fellowship. The University of Nottingham DNP MAS NMR Facility used in this research was funded by EPSRC and the University of Nottingham, and assistance from the Facility Manager (Subhradip Paul, University of Nottingham) is also acknowledged. This work was also supported by ERC Advanced Grant No. 320860. The research data (and/or materials) supporting this publication can be accessed at DOI: http://dx.doi.org/10.17630/00533fb3-e938-498d-bfe4-f07d82c309d6.Isotopic enrichment of 29Si and DNP-enhanced NMR spectroscopy are combined to determine the detailed surface structure of a silicated alumina catalyst. The significant sensitivity enhancement provided by DNP is vital to the acquisition of multinuclear and multidimensional experiments that provide information on the atomic-level structure of the species present at the surface. Isotopic enrichment not only facilitates spectral acquisition, particularly given the low (1.5 wt%) Si loading, but also enables spectra with higher resolution than those acquired using DNP to be obtained. The unexpected similarity of conventional, CP and DNP NMR spectra is attributed to the presence of adventitious surface water that forms a sufficiently dense 1H network at the silica surface so as to mediate efficient polarization transfer to all Si species regardless of their chemical nature. Spectra reveal the presence of Si-O-Si linkages at the surface (identified as Q4(3Al)-Q4(3Al)), and confirm that the anchoring of the surface overlayer with the alumina occurs through AlIV and AlV species only. This suggests the presence of Q3/Q4 Si at the surface affects the neighboring Al species, modifying the surface structure and making it less likely AlVI environments are in close spatial proximity. In contrast, Q1/Q2 species, bonded to the surface by fewer covalent bonds, have less of an effect on the surface and more AlVI species are consequently found nearby. The combination of isotropic enrichment and DNP provides a definitive and fully quantitative description of the Si-modified alumina surface, and we demonstrate that almost one-third of the silicon at the surface is connected to another Si species, even at the low level of coverage used, lowering the propensity for the formation of Brønsted acid sites. This suggests that a variation in the synthetic procedure might be required to obtain a more even coverage for optimum performance. The work here will allow for more rigorous future investigations of structure-function relationships in these complex materials.PostprintPeer reviewe

Random matrix ensembles of time correlation matrices to analyze visual lifelogs

Visual lifelogging is the process of automatically recording images and other sensor data for the purpose of aiding memory recall. Such lifelogs are usually created using wearable cameras. Given the vast amount of images that are maintained in a visual lifelog, it is a significant challenge for users to deconstruct a sizeable collection of images into meaningful events. In this paper, random matrix theory (RMT) is applied to a cross-correlation matrix C, constructed using SenseCam lifelog data streams to identify such events. The analysis reveals a number of eigenvalues that deviate from the spectrum suggested by RMT. The components of the deviating eigenvectors are found to correspond to “distinct significant events” in the visual lifelogs. Finally, the cross-correlation matrix C is cleaned by separating the noisy part from the non-noisy part. Overall, the RMT technique is shown to be useful to detect major events in SenseCam images

Residue 82 of the Chikungunya Virus E2 Attachment Protein Modulates Viral Dissemination and Arthritis in Mice

Chikungunya virus (CHIKV) is a mosquito-borne alphavirus that has reemerged to cause profound epidemics of fever, rash, and arthralgia throughout sub-Saharan Africa, Southeast Asia, and the Caribbean. Like other arthritogenic alphaviruses, mechanisms of CHIKV pathogenesis are not well defined. Using the attenuated CHIKV strain 181/25 and virulent strain AF15561, we identified a residue in the E2 viral attachment protein that is a critical determinant of viral replication in cultured cells and pathogenesis in vivo. Viruses containing an arginine at E2 residue 82 displayed enhanced infectivity in mammalian cells but reduced infectivity in mosquito cells and diminished virulence in a mouse model of CHIKV disease. Mice inoculated with virus containing an arginine at this position exhibited reduced swelling at the site of inoculation with a concomitant decrease in the severity of necrosis in joint-associated tissues. Viruses containing a glycine at E2 residue 82 produced higher titers in the spleen and serum at early times postinfection. Using wild-type and glycosaminoglycan (GAG)-deficient Chinese hamster ovary (CHO) cell lines and soluble GAGs, we found that an arginine at residue 82 conferred greater dependence on GAGs for infection of mammalian cells. These data suggest that CHIKV E2 interactions with GAGs diminish dissemination to lymphoid tissue, establishment of viremia, and activation of inflammatory responses early in infection. Collectively, these results suggest a function for GAG utilization in regulating CHIKV tropism and host responses that contribute to arthritis

A Single-Amino-Acid Polymorphism in Chikungunya Virus E2 Glycoprotein Influences Glycosaminoglycan Utilization

Chikungunya virus (CHIKV) is a reemerging arbovirus responsible for outbreaks of infection throughout Asia and Africa, causing an acute illness characterized by fever, rash, and polyarthralgia. Although CHIKV infects a broad range of host cells, little is known about how CHIKV binds and gains access to the target cell interior. In this study, we tested whether glycosaminoglycan (GAG) binding is required for efficient CHIKV replication using CHIKV vaccine strain 181/25 and clinical isolate SL15649. Preincubation of strain 181/25, but not SL15649, with soluble GAGs resulted in dose-dependent inhibition of infection. While parental Chinese hamster ovary (CHO) cells are permissive for both strains, neither strain efficiently bound to or infected mutant CHO cells devoid of GAG expression. Although GAGs appear to be required for efficient binding of both strains, they exhibit differential requirements for GAGs, as SL15649 readily infected cells that express excess chondroitin sulfate but that are devoid of heparan sulfate, whereas 181/25 did not. We generated a panel of 181/25 and SL15649 variants containing reciprocal amino acid substitutions at positions 82 and 318 in the E2 glycoprotein. Reciprocal exchange at residue 82 resulted in a phenotype switch; Gly82 results in efficient infection of mutant CHO cells but a decrease in heparin binding, whereas Arg82 results in reduced infectivity of mutant cells and an increase in heparin binding. These results suggest that E2 residue 82 is a primary determinant of GAG utilization, which likely mediates attenuation of vaccine strain 181/25