Differential regulation of tetramerization of the AMPA receptor glutamate-gated ion channel by auxiliary subunits.

α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) auxiliary subunits are specialized, nontransient binding partners of AMPARs that modulate AMPAR channel gating properties and pharmacology, as well as their biogenesis and trafficking. The most well-characterized families of auxiliary subunits are transmembrane AMPAR regulatory proteins (TARPs), cornichon homologs (CNIHs), and the more recently discovered GSG1-L. These auxiliary subunits can promote or reduce surface expression of AMPARs (composed of GluA1-4 subunits) in neurons, thereby impacting their functional role in membrane signaling. Here, we show that CNIH-2 enhances the tetramerization of WT and mutant AMPARs, presumably by increasing the overall stability of the tetrameric complex, an effect that is mainly mediated by interactions with the transmembrane domain of the receptor. We also find CNIH-2 and CNIH-3 show receptor subunit-specific actions in this regard with CNIH-2 enhancing both GluA1 and GluA2 tetramerization, whereas CNIH-3 only weakly enhances GluA1 tetramerization. These results are consistent with the proposed role of CNIHs as endoplasmic reticulum cargo transporters for AMPARs. In contrast, TARP γ-2, TARP γ-8, and GSG1-L have no or negligible effect on AMPAR tetramerization. On the other hand, TARP γ-2 can enhance receptor tetramerization but only when directly fused with the receptor at a maximal stoichiometry. Notably, surface expression of functional AMPARs was enhanced by CNIH-2 to a greater extent than TARP γ-2, suggesting that this distinction aids in maturation and membrane expression. These experiments define a functional distinction between CNIHs and other auxiliary subunits in the regulation of AMPAR biogenesis.

Review of terrestrial temporarily conserved areas in Canada, the United States, and Mexico.

The establishment of protected areas is a cornerstone of conservation, but permanent protection could be inefficient or even impossible in some situations. We synthesized the literature on temporarily conserved areas (TCAs) across Canada, the United States, and Mexico. We used a comprehensive search string to retrieve peer-reviewed articles published from 2000 to 2021 from the Web of Science. We identified 27 relevant peer-reviewed articles that examined the potential benefits of TCAs in the study area, indicating TCA is a relatively understudied area of research in the peer-reviewed literature. The TCA studies were highly clustered; 77% of studies focused on protecting a single life stage of migratory species and 61% of studies related to temporary conservation of breeding or staging habitats for migratory birds. Ninety-three percent of studies focused on preventing human-driven threats, mainly on public lands of coastal areas, the Great Plains, and the Mississippi Valley in the central United States. Short-term and experimental studies were the dominant study types. TCAs have the potential to complement permanently protected areas and provide protection when permanent protection is difficult. Some included studies examined their conservation value, but the ecological, social, and economic outcomes of TCAs are unclear. More TCA research is needed to determine the role they could play in conservation worldwide. Embracing the concept of TCAs as conservation tool could lead to more comprehensive and consistent reporting of the outcomes of temporary area-based conservation measures. However, a global review and analysis of effectiveness of TCAs will be required if they are to play a formal role in meeting international targets for biodiversity conservation.

Revisión de áreas terrestres conservadas temporalmente en Canadá, Estados Unidos y México Resumen La creación de áreas protegidas es una piedra angular de la conservación, aunque en algunos casos la protección permanente podría ser ineficiente o incluso imposible. Condensamos la literatura sobre las áreas de conservación temporal (ACT) en Canadá, Estados Unidos y México. Usamos una cadena completa de búsqueda para obtener artículos revisados por pares publicados del 2000 al 2021 en Web of Science. Identificamos 27 artículos relevantes que analizaban el potencial de las ACT en el área de estudio, lo que indica que las ACT es un área poco estudiada en la literatura revisada por pares. Los estudios sobre ACT estaban muy agrupados: el 77% se enfocaban en la protección de un solo estadio de vida de las especies migratorias y el 61% se relacionaban con la conservación temporal de los hábitats de reproducción o de descanso de las aves migratorias. El 93% de los estudios se enfocó en la prevención de amenazas causadas por humanos, principalmente en los terrenos públicos de las áreas costeras, las Grandes Llanuras y el valle del Mississippi en el centro de los Estados Unidos. Los estudios experimentales y a corto plazo fueron el tipo de estudio dominante. Las áreas de conservación temporal tienen el potencial para complementar las áreas de protección permanente y proporcionar protección cuando es complicado proporcionarla permanentemente. Algunos de los estudios incluidos analizaron el valor para la conservación de las ACT, pero aún no están claros sus resultados ecológicos, sociales y económicos. Se necesita más investigación sobre las ACT para determinar el papel que podrían tener en la conservación mundial. Si se acepta el concepto de ACT como una herramienta de conservación, se podrían reportar los resultados de las medidas de conservación basadas en las ACT de forma más completa y consistente. Sin embargo, se requerirá una revisión y análisis global de la eficiencia de las ACT si se espera que tengan un papel formal en el cumplimiento de los objetivos internacionales de la conservación de la biodiversidad.

Systematic conservation prioritization with the prioritizr R package.

Plans for expanding protected area systems (prioritizations) need to fulfill conservation objectives. They also need to account for other factors, such as economic feasibility and anthropogenic land-use requirements. Although prioritizations are often generated with decision support tools, most tools have limitations that hinder their use for decision-making. We outlined how the prioritizr R package (https://prioritizr.net) can be used for systematic conservation prioritization. This decision support tool provides a flexible interface to build conservation planning problems. It can leverage a variety of commercial (e.g., Gurobi) and open-source (e.g., CBC and SYMPHONY) exact algorithm solvers to identify optimal solutions in a short period. It is also compatible with a variety of spatially explicit (e.g., ESRI Shapefile, GeoTIFF) and nonspatial tabular (e.g., Microsoft Excel Spreadsheet) data formats. Additionally, it provides functionality for evaluating prioritizations, such as assessing the relative importance of different places selected by a prioritization. To showcase the prioritizr R package, we applied it to a case study based in Washington state (United States) for which we developed a prioritization to improve protected area coverage of native avifauna. We accounted for land acquisition costs, existing protected areas, places that might not be suitable for protected area establishment, and spatial fragmentation. We also conducted a benchmark analysis to examine the performance of different solvers. The prioritization identified 12,400 km2 of priority areas for increasing the percentage of species' distributions covered by protected areas. Although open source and commercial solvers were able to quickly solve large-scale conservation planning problems, commercial solvers were required for complex, large-scale problems.. The prioritizr R package is available on the Comprehensive R Archive Network (CRAN). In addition to reserve selection, it can inform habitat restoration, connectivity enhancement, and ecosystem service provisioning. It has been used in numerous conservation planning exercises to inform best practices and aid real-world decision-making.

Priorización de la conservación sistemática con el paquete prioritizr R Resumen Los planes para expandir los sistemas de áreas protegidas (priorizaciones) necesitan cumplir con los objetivos de conservación. También necesitan considerar otros factores, como la viabilidad económica y los requerimientos para el uso antropogénico del suelo. Aunque con frecuencia las priorizaciones se generan con herramientas de apoyo para decidir, la mayoría de estas herramientas tienen limitantes que complican su uso en la toma de decisiones. Esbozamos cómo el paquete prioritizr R (https://prioritizr.net) puede usarse para la priorización de la conservación sistemática. Esta herramienta de apoyo para decidir proporciona una interfaz flexible para construir problemas de la planeación de la conservación. También puede sacar provecho de una variedad de solucionadores exactos de algoritmos comerciales (p. ej.: Gurobi) y de fuentes abiertas (p. ej.: CBC y SYMPHONY) para identificar soluciones óptimas en un periodo breve. La herramienta también es compatible con una variedad de formatos de datos tabulares con espacialidad explícita (p. ej.: ESRI Shapefile, GeoTIFF) y sin espacialidad (p. ej.: hojas de cálculo de Microsoft Excel). Además, proporciona la funcionalidad para evaluar las priorizaciones, como el análisis de la importancia relativa de los diferentes lugares seleccionados por una priorización. Para mostrar la funcionalidad del paquete prioritizr R, lo aplicamos a un estudio de caso en el Estado de Washington, Estado Unidos, para el cual desarrollamos una priorización para mejorar la cobertura del área protegida de la avifauna nativa. Consideramos los costos de adquisición de tierras, las áreas protegidas existentes y la fragmentación espacial. También realizamos un análisis comparativo para examinar el desempeño de los diferentes solucionadores. La priorización identificó 12,400 km2 de áreas prioritarias para incrementar el porcentaje de la distribución de especies cubiertas por las áreas protegidas. Aunque los solucionadores comerciales y de fuente abierta lograron resolver rápidamente los problemas de conservación a gran escala, sólo los comerciales fueron requeridos para los problemas complejos de gran escala. El paquete prioritizr R está disponible en el Comprehensive R Archive Network (CRAN). Además de seleccionar las reservas, el paquete puede informar la restauración de hábitat, la mejora de la conectividad y el suministro de servicios ambientales. El paquete se ha usado en varios ejercicios para informar las mejores prácticas y ayudar a la toma de decisiones en el mundo real.

Challenges in assessing the effects of environmental governance systems on conservation outcomes.

Effective governance is crucial for the success of conservation projects aimed at protecting wildlife populations and supporting human well-being. However, few large-scale, comprehensive syntheses have been conducted on the effects of different environmental governance types on conservation outcomes (i.e., biological and ecological effectiveness or effects of conservation on human well-being), and clarity on the quantity and quality of evidence remains dispersed and ambiguous. We attempted a systematic map of the evidence on the effectiveness of different governance types to meet desired conservation outcomes in Africa, Asia, and Latin America. However, early in this effort, we observed a general lack of empirical research on the links between governance and conservation outcomes. To fill observed data gaps in the evidence base, we tried triangulating governance data from alternative sources (Protected Planet database) and pooling evidence from research conducted within the same conservation areas. Limited data were contained in the Protected Planet database, and governance types in conservation areas and landscapes were complex, making it difficult to use these approaches to assign governance types to conservation areas. To illustrate our observations from the failed systematic map attempt, we prepared a rapid evidence map that outlines a subset of the evidence base of articles linking governance types and governance principles with conservation outcomes. Only 3.2% (34 of 1067) of the articles we screened directly related conservation outcomes to governance type, and even fewer related governance principles to conservation outcomes. Based on our findings, we recommend improving the evidence base by supporting empirical research and increasing the availability and quality of governance data in freely accessible databases. These recommendations are critical for enhancing understanding of the role of governance in conservation projects and improving conservation outcomes.

Retos para la evaluación de los efectos de los sistemas de gestión ambiental sobre los resultados de conservación Resumen Una gestión eficaz es crucial para el éxito de los proyectos de conservación destinados a proteger las poblaciones de fauna y flora y apoyar el bienestar humano. Sin embargo, hay pocas síntesis exhaustivas a gran escala sobre los efectos de los distintos tipos de gestión ambiental en los resultados de conservación (es decir, la eficacia biológica y ecológica o los efectos de la conservación sobre el bienestar humano), y la claridad sobre la cantidad y calidad de las pruebas todavía está dispersa y ambigua. Intentamos elaborar un mapa sistemático con evidencias de la eficacia de los distintos tipos de gestión para logar los resultados de conservación deseados en África, Asia y América Latina. Sin embargo, al principio de este esfuerzo observamos una falta general de investigación empírica sobre los vínculos entre la gestión y los resultados de la conservación. Para cerrar las brechas observadas en la base de pruebas, intentamos triangular los datos sobre gobernanza procedentes de fuentes alternativas (base de datos Protected Planet) y agrupar las pruebas de las investigaciones realizadas en las mismas áreas de conservación. La base de datos Protected Planet tenía datos limitados y los tipos de gestión en las áreas de conservación y los paisajes eran complejos, lo que complicaba el uso de estos enfoques para asignar tipos de gestión a las áreas de conservación. Para ilustrar nuestras observaciones a partir del mapa sistemático fallido, preparamos un mapa rápido con evidencias que resumía un subconjunto de la base de pruebas de artículos que vinculan los tipos y los principios de gestión con los resultados de conservación. Sólo el 3.2% (34 de 1067) de los artículos analizados relacionaban directamente los resultados de conservación con el tipo de gestión; fueron menos los que relacionaban los principios de gestión con los resultados de conservación. Con base en nuestros hallazgos, recomendamos mejorar la base de pruebas con apoyo a la investigación empírica y aumentando la disponibilidad y la calidad de los datos sobre gestiones en bases de datos de libre acceso. Estas recomendaciones son fundamentales para comprender mejor el papel de la gestión en los proyectos de conservación y mejorar los resultados de la conservación.

Integrating the melanoma 31-gene expression profile test with clinical and pathologic features can provide personalized precision estimates for sentinel lymph node positivity: an independent performance cohort.

INTRODUCTION: Up to 88% of sentinel lymph node biopsies (SLNBs) are negative. The 31-gene expression profile (31-GEP) test can help identify patients with a low risk of SLN metastasis who can safely forego SLNB. The 31-GEP classifies patients as low (Class 1 A), intermediate (Class 1B/2A), or high risk (Class 2B) for recurrence, metastasis, and SLN positivity. The integrated 31-GEP (i31-GEP) combines the 31-GEP risk score with clinicopathologic features using a neural network algorithm to personalize SLN risk prediction. METHODS: Patients from a single surgical center with 31-GEP results were included (n = 156). An i31-GEP risk prediction < 5% was considered low risk of SLN positivity. Chi-square was used to compare SLN positivity rates between groups. RESULTS: Patients considered low risk by the i31-GEP had a 0% (0/30) SLN positivity rate compared to a 31.9% (30/94, p < 0.001) positivity rate in those with > 10% risk. Using the i31-GEP to guide SLNB decisions could have significantly reduced the number of unnecessary SLNBs by 19.2% (30/156, p < 0.001) for all patients and 33.0% (30/91, p < 0.001) for T1-T2 tumors. Patients with T1-T2 tumors and an i31-GEP-predicted SLN positivity risk > 10% had a similar SLN positivity rate (33.3%) as patients with T3-T4 tumors (31.3%). CONCLUSION: The i31-GEP identified patients with < 5% risk of SLN positivity who could safely forego SLNB. Combining the 31-GEP with clinicopathologic features for a precise risk estimate can help guide risk-aligned patient care decisions for SLNB to reduce the number of unnecessary SLNBs and increase the SLNB positivity yield if the procedure is performed.

A multi-omics approach to lignocellulolytic enzyme discovery reveals a new ligninase activity from Parascedosporium putredinis NO1.

Lignocellulose, the structural component of plant cells, is a major agricultural byproduct and the most abundant terrestrial source of biopolymers on Earth. The complex and insoluble nature of lignocellulose limits its conversion into value-added commodities, and currently, efficient transformation requires expensive pretreatments and high loadings of enzymes. Here, we report on a fungus from the Parascedosporium genus, isolated from a wheat-straw composting community, that secretes a large and diverse array of carbohydrate-active enzymes (CAZymes) when grown on lignocellulosic substrates. We describe an oxidase activity that cleaves the major ß-ether units in lignin, thereby releasing the flavonoid tricin from monocot lignin and enhancing the digestion of lignocellulose by polysaccharidase mixtures. We show that the enzyme, which holds potential for the biorefining industry, is widely distributed among lignocellulose-degrading fungi from the Sordariomycetes phylum.

Protected area planning to conserve biodiversity in an uncertain future.

Protected areas are a key instrument for conservation. Despite this, they are vulnerable to risks associated with weak governance, land-use intensification, and climate change. We used a novel hierarchical optimization approach to identify priority areas for expanding the global protected area system that explicitly accounted for such risks while maximizing protection of all known terrestrial vertebrate species. To incorporate risk categories, we built on the minimum set problem, where the objective is to reach species distribution protection targets while accounting for 1 constraint, such as land cost or area. We expanded this approach to include multiple objectives accounting for risk in the problem formulation by treating each risk layer as a separate objective in the problem formulation. Reducing exposure to these risks required expanding the area of the global protected area system by 1.6% while still meeting conservation targets. Incorporating risks from weak governance drove the greatest changes in spatial priorities for protection, and incorporating risks from climate change required the largest increase (2.52%) in global protected area. Conserving wide-ranging species required countries with relatively strong governance to protect more land when they bordered nations with comparatively weak governance. Our results underscore the need for cross-jurisdictional coordination and demonstrate how risk can be efficiently incorporated into conservation planning. Planeación de las áreas protegidas para conservar la biodiversidad en un futuro incierto.

Aunque las áreas protegidas son un instrumento clave para la conservación, no dejan de ser vulnerables a los riesgos asociados a una gestión pobre, la intensificación del uso de suelo y al cambio climático. Usamos una estrategia novedosa de optimización jerárquica para identificar las áreas prioritarias para la expansión del sistema global de áreas protegidas. La estrategia consideró de manera explícita los riesgos mencionados y también maximizó la protección de todas las especies conocidas de vertebrados terrestres. Para incorporar a las categorías de riesgo partimos del mínimo problema establecido, en donde el objetivo es lograr los objetivos de protección de la distribución de especies mientras se considera sólo una restricción, como el costo o área del suelo. Expandimos esta estrategia para que incluyera varios objetivos que consideraran el riesgo desde la formulación del problema mediante el manejo de cada nivel de riesgo como un objetivo aparte durante la formulación del problema. La reducción de la exposición a estos riesgos requirió que se expandiera el área total del sistema global de áreas protegidas en un 1.6% y así todavía cumplir con los objetivos de conservación. La incorporación de riesgos a partir de una gestión pobre fue el principal impulsor de cambios en las prioridades espaciales para la protección, mientras que la incorporación de riesgos a partir del cambio climático requirió el mayor incremento (2.52%) del área protegida a nivel mundial. La conservación de especies con distribución amplia requirió que los países con una gestión relativamente fuerte protegieran más suelo al tener fronteras con países con una gestión pobre en comparación son la suya. Nuestros resultados destacan la necesidad de una coordinación entre jurisdicciones y demuestran cómo puede incorporarse el riesgo de manera exitosa a la planeación de la conservación.

Giant and Controllable Photoplasticity and Photoelasticity in Compound Semiconductors.

We show that the wide-band gap compound semiconductors ZnO, ZnS, and CdS feature large photoplastic and photoelastic effects that are mediated by point defects. We measure the mechanical properties of ceramics and single crystals using nanoindentation, and we find that elasticity and plasticity vary strongly with moderate illumination. For instance, the elastic stiffness of ZnO can increase by greater than 40% due to blue illumination of intensity 1.4 mW/cm^{2}. Above-band-gap illumination (e.g., uv light) has the strongest effect, and the relative effect of subband gap illumination varies between samples-a clear sign of defect-mediated processes. We show giant optomechanical effects can be tuned by materials processing, and that processing dependence can be understood within a framework of point defect equilibrium. The photoplastic effect can be understood by a long-established theory of charged dislocation motion. The photoelastic effect requires a new theoretical framework which we present using density functional theory to study the effect of point defect ionization on local lattice structure and elastic tensors. Our results update the longstanding but lesser-studied field of semiconductor optomechanics, and suggest interesting applications.

Closing the knowledge-action gap in conservation with open science.

The knowledge-action gap in conservation science and practice occurs when research outputs do not result in actions to protect or restore biodiversity. Among the diverse and complex reasons for this gap, three barriers are fundamental: knowledge is often unavailable to practitioners and challenging to interpret or difficult to use or both. Problems of availability, interpretability, and useability are solvable with open science practices. We considered the benefits and challenges of three open science practices for use by conservation scientists and practitioners. First, open access publishing makes the scientific literature available to all. Second, open materials (detailed methods, data, code, and software) increase the transparency and use of research findings. Third, open education resources allow conservation scientists and practitioners to acquire the skills needed to use research outputs. The long-term adoption of open science practices would help researchers and practitioners achieve conservation goals more quickly and efficiently and reduce inequities in information sharing. However, short-term costs for individual researchers (insufficient institutional incentives to engage in open science and knowledge mobilization) remain a challenge. We caution against a passive approach to sharing that simply involves making information available. We advocate a proactive stance toward transparency, communication, collaboration, and capacity building that involves seeking out and engaging with potential users to maximize the environmental and societal impact of conservation science.

Cierre de la Brecha entre el Conocimiento y la Acción en la Conservación con Ciencia Abierta 21-311 Resumen La brecha entre el conocimiento y la acción en las ciencias de la conservación y en su práctica ocurre cuando los resultados de las investigaciones no derivan en acciones para proteger o restaurar la biodiversidad. Entre las razones complejas y diversas de esta brecha, existen tres barreras que son fundamentales: con frecuencia el conocimiento no está disponible para los practicantes, es difícil de interpretar o difícil de usar, o ambas. Los problemas con la disponibilidad, interpretabilidad y utilidad son solucionables mediante las prácticas de ciencia abierta. Consideramos los beneficios y los obstáculos de tres prácticas de ciencia abierta para su uso por parte de los científicos y practicantes de la conservación. Primero, las publicaciones de acceso abierto hacen que la literatura científica esté disponible para todos. Segundo, los materiales abiertos (métodos detallados, datos, códigos y software) incrementan la transparencia y el uso de los hallazgos de las investigaciones. Tercero, los recursos educativos abiertos permiten que los científicos y practicantes de la conservación adquieran las habilidades necesarias para utilizar los productos de las investigaciones. La adopción a largo plazo de las prácticas de ciencia abierta ayudaría a los investigadores y a los practicantes a lograr los objetivos de conservación mucho más rápido y de manera eficiente y a reducir las desigualdades que existen en la divulgación de información. Sin embargo, los costos a corto plazo para los investigadores individuales (incentivos institucionales insuficientes para participar en la ciencia abierta y en la movilización del conocimiento) todavía son un reto. Advertimos sobre las estrategias pasivas de divulgación que simplemente hacen que la información esté disponible. Abogamos por una postura proactiva hacia la transparencia, la comunicación, la colaboración y la construcción de las capacidades que incluyen la búsqueda de y la interacción con los usuarios potenciales para maximizar el impacto ambiental y social de las ciencias de la conservación.

Global assessment of marine and freshwater recreational fish reveals mismatch in climate change vulnerability and conservation effort.

Recreational fisheries contribute substantially to the sociocultural and economic well-being of coastal and riparian regions worldwide, but climate change threatens their sustainability. Fishery managers require information on how climate change will impact key recreational species; however, the absence of a global assessment hinders both directed and widespread conservation efforts. In this study, we present the first global climate change vulnerability assessment of recreationally targeted fish species from marine and freshwater environments (including diadromous fishes). We use climate change projections and data on species' physiological and ecological traits to quantify and map global climate vulnerability and analyze these patterns alongside the indices of socioeconomic value and conservation effort to determine where efforts are sufficient and where they might fall short. We found that over 20% of recreationally targeted fishes are vulnerable to climate change under a high emission scenario. Overall, marine fishes had the highest number of vulnerable species, concentrated in regions with sensitive habitat types (e.g., coral reefs). However, freshwater fishes had higher proportions of species at risk from climate change, with concentrations in northern Europe, Australia, and southern Africa. Mismatches in conservation effort and vulnerability were found within all regions and life-history groups. A key pattern was that current conservation effort focused primarily on marine fishes of high socioeconomic value rather than on the freshwater and diadromous fishes that were predicted to be proportionately more vulnerable. While several marine regions were notably lacking in protection (e.g., Caribbean Sea, Banda Sea), only 19% of vulnerable marine species were without conservation effort. By contrast, 72% of freshwater fishes and 33% of diadromous fishes had no measures in place, despite their high vulnerability and cultural value. The spatial and taxonomic analyses presented here provide guidance for the future conservation and management of recreational fisheries as climate change progresses.

Surface Transformations of Lead Oxides and Carbonates Using First-Principles and Thermodynamics Calculations.

Lead (Pb)-containing solids find widespread commercial use in batteries, piezoelectrics, and as starting materials for synthesis. Here, we combine density functional theory (DFT) and thermodynamics in a DFT + solvent ion model to compare the surface reactivity of Pb oxides and carbonates, specifically litharge, massicot, and cerussite, in contact with water. The information provided by this model is used to delineate structure-property relationships for surfaces that are able to release Pb as Pb2+. We find that Pb2+ release is dependent on pH and chemical bonding environment and go on to correlate changes in the surface bonding to key features of the electronic structure through a projected density of states analysis. Collectively, our analyses link the atomistic structure to i) specific electronic states and ii) the thermodynamics of surface transformations, and the results presented here can be used to guide synthetic efforts of Pb2+-containing materials in aqueous media or be used to better understand the initial steps in solid decomposition.

Density functional theory and thermodynamics analysis of MAl12 Keggin substitution reactions: Insights into ion incorporation and experimental confirmation.

Polyaluminum cations, such as the MAl12 Keggin, undergo atomic substitutions at the heteroatom site (M), where nanoclusters with M = Al3+, Ga3+, and Ge4+ have been experimentally studied. The identity of the heteroatom M has been shown to influence the structural and electronic properties of the nanocluster and the kinetics of ligand exchange reactions. To date, only three ε-analogs have been identified, and there is a need for a predictive model to guide experiment to the discovery of new MAl12 species. Here, we present a density functional theory (DFT) and thermodynamics approach to predicting favorable heteroatom substitution reactions, alongside structural analyses on hypothetical ε-MAl12 nanocluster models. We delineate trends in energetics and geometry based on heteroatom cation properties, finding that Al3+-O bond lengths are related to heteroatom cation size, charge, and speciation. Our analyses also enable us to identify potentially isolable new ε-MAl12 species, such as FeAl12 7+. Based upon these results, we evaluated the Al3+/Zn2+/Cr3+ system and determined that substitution of Cr3+ is unfavorable in the heteroatom site but is preferred for Zn2+, in agreement with the experimental structures. Complimentary experimental studies resulted in the isolation of Cr3+-substituted δ-Keggin species where Cr3+ substitution occurs only in the octahedral positions. The isolated structures Na[AlO4Al9.6Cr2.4(OH)24(H2O)12](2,6-NDS)4(H2O)22 (δ-CrnAl13-n-1) and Na[AlO4Al9.5Cr2.5(OH)24(H2O)12](2,7-NDS)4(H2O)18.5 (δ-CrnAl13-n-2) are the first pieces of evidence of mixed Al3+/Cr3+ Keggin-type nanoclusters that prefer substitution at the octahedral sites. The δ-CrnAl13-n-2 structure also exhibits a unique placement of the bound Na+ cation, which may indicate that Cr3+ substitution can alter the surface reactivity of Keggin-type species.

Relative costs of conserving threatened species across taxonomic groups.

Bias toward legally protecting and prioritizing charismatic taxonomic groups, such as mammals and birds, and against others, such as insects and plants, is well documented. However, the relative costs of conserving various taxonomic groups and the potential of these costs to interact with existing biases have been much less explored. We analyzed conservation programs across more than 2,000 species in 3 countries to investigate the costs of conserving species within taxonomic groups and how these costs might affect conservation planning. For each data set, we tested for differences in mean annual cost among taxonomic groups. For the data set from the United States, recovery plans differed in duration, so we also tested for differences in total costs among taxonomic groups. Although the costs for individual species varied widely, there were strong international consistencies. For example, mammals cost 8-26 times more on average to conserve than plants and 13-19 times more to conserve than aquatic invertebrates. On average, bird species cost 5-30 times more to conserve than plants and 6-14 times more to conserve than aquatic invertebrates. These cost differences could exacerbate unequal resource allocation among taxonomic groups such that more charismatic groups both receive more attention and require more resources, leading to neglect of other taxonomic groups.

Costos Relativos de la Conservación de Especies Amenazadas entre Grupos Taxonómicos Resumen El sesgo hacia la protección legal y la priorización de grupos taxonómicos carismáticos, como los mamíferos y las aves, y el sesgo que no favorece a otros grupos, como los insectos y las plantas, está bien documentado. A pesar de esto, los costos relativos de la conservación de varios grupos taxonómicos y el potencial que tienen estos costos para interactuar con los sesgos existentes no han sido explorados a profundidad. Analizamos los programas de conservación para más de 2,000 especies en tres países y así investigar los costos de la conservación de especies limitada a los grupos taxonómicos y cómo estos costos podrían afectar a la planeación de la conservación. Buscamos diferencias en el costo medio anual entre los grupos taxonómicos en cada conjunto de datos. Para el conjunto de datos de los Estados Unidos, los planes de recuperación difirieron en su duración, por lo que también buscamos diferencias en los costos totales entre los grupos taxonómicos. Aunque los costos para cada especie individual variaron ampliamente, hubo consistencias internacionales sólidas. Por ejemplo, la conservación de los mamíferos cuesta en promedio de 8-26 veces más que la de las plantas y de 13-19 veces más que la de los invertebrados acuáticos. En promedio, cuesta de 5-30 veces más la conservación de especies de aves que la de las plantas y de 6-14 veces más que la de los invertebrados acuáticos. Estas diferencias en los costos podrían agravar la asignación desigual de recursos entre los grupos taxonómicos de tal manera que los grupos taxonómicos más carismáticos reciben más atención y requieren de más recursos, resultando en el descuido de otros grupos taxonómicos.

Three lessons conservation science can learn from the COVID-19 pandemic.

Article impact statement: COVID-19 has demonstrated the need to optimize research activity, convey the gravity of loss, and reevaluate merit in conservation science.

Homogenization of freshwater lakes: Recent compositional shifts in fish communities are explained by gamefish movement and not climate change.

Globally, lake fish communities are being subjected to a range of scale-dependent anthropogenic pressures, from climate change to eutrophication, and from overexploitation to species introductions. As a consequence, the composition of these communities is being reshuffled, in most cases leading to a surge in taxonomic similarity at the regional scale termed homogenization. The drivers of homogenization remain unclear, which may be a reflection of interactions between various environmental changes. In this study, we investigate two potential drivers of the recent changes in the composition of freshwater fish communities: recreational fishing and climate change. Our results, derived from 524 lakes of Ontario, Canada sampled in two periods (1965-1982 and 2008-2012), demonstrate that the main contributors to homogenization are the dispersal of gamefish species, most of which are large predators. Alternative explanations relating to lake habitat (e.g., area, phosphorus) or variations in climate have limited explanatory power. Our analysis suggests that human-assisted migration is the primary driver of the observed compositional shifts, homogenizing freshwater fish community among Ontario lakes and generating food webs dominated by gamefish species.

DFT Computed Dielectric Response and THz Spectra of Organic Co-Crystals and Their Constituent Components.

Terahertz (THz) spectroscopy has been put forth as a non-contact, analytical probe to characterize the intermolecular interactions of biologically active molecules, specifically as a way to understand, better develop, and use active pharmaceutical ingredients. An obstacle towards fully utilizing this technique as a probe is the need to couple features in the THz regions to specific vibrational modes and interactions. One solution is to use density functional theory (DFT) methods to assign specific vibrational modes to signals in the THz region, coupling atomistic insights to spectral features. Here, we use open source planewave DFT packages that employ ultrasoft pseudopotentials to assess the infrared (IR) response of organic compounds and complex co-crystal formulations in the solid state, with and without dispersion corrections. We compare our DFT computed lattice parameters and vibrational modes to experiment and comment on how to improve the agreement between theory and modeling to allow for THz spectroscopy to be used as an analytical probe in complex biologically relevant systems.

First-Principles and Thermodynamics Study of Compositionally Tuned Complex Metal Oxides: Cation Release from the (001) Surface of Mn-Rich Lithium Nickel Manganese Cobalt Oxide.

Compositional tuning of nanoscale complex metal oxides (CMOs) can lead to enhanced performance and favorable properties for a variety of energy-related applications. However, investigations of the nanoscale CMOs used in energy storage technologies demonstrate that these nanomaterials may have an adverse biological impact, highlighting a fundamental knowledge gap between nanomaterial design and the structure and properties at the end of life. CMO nanomaterials can enter the environment due to improper disposal, where they undergo subsequent (as of yet poorly understood) nanoscale transformations that may affect biological response and, ultimately, environmental fate. This points to the need for studies at the nano-bio interface that can be used to shape rules for the redesign of CMOs: materials that are are potentially more benign by design and serve as examples of sustainable nanotechnology. The example given here is to enrich lithium nickel manganese cobalt oxide, Li x(Ni yMn zCo1- y- z)O2 (NMC), with Mn to create a family of materials that are less expensive and potentially less toxic to a wide range of organisms. In this paper, we investigate the structure and electronic states of Mn-rich NMC at the density functional theory (DFT) level to elucidate the interplay of redox properties, oxidation state, and coordination environment of a compositionally tuned CMO. We find that the oxidation states of Ni and Co remain mostly unaffected while Mn exists as both Mn2+ and Mn4+. Our models show that the ratio of Mn2+ and Mn4+ varies with changes in the coordination environment, such as the identity of neighboring atoms and surface OH group coverage. The surface metal release properties of Mn-rich NMC compositions are predicted using a DFT + solvent ion model and show that Mn-rich NMC compositions are inherently more prone to dissolution than NMC and that this is attributed to the changes in oxidation state of the transition metals in Mn-rich NMC.

Dissolution of Complex Metal Oxides from First-Principles and Thermodynamics: Cation Removal from the (001) Surface of Li(Ni1/3Mn1/3Co1/3)O2.

The rapid increase in use of Li-ion batteries in portable electronics has created a pressing need to understand the environmental impact and long-term fate of electonic waste (e-waste) products such as heavy and/or reactive metals. The type of e-waste that we focus on here are the complex metal oxide nanomaterials that compose Li-ion battery cathodes. While in operation the complex metal oxides are in a hermetically sealed container. However, at the end of life, improper disposal can cause structural transformations such as dissolution and metal leaching, resulting in a significant exposure risk to the surrounding environment. The transformations that occur between operational to environmental settings gives rise to a stark knowledge gap between macroscopic design and molecular-level behavior. In this study we use theory and modeling to describe and explain previously published experimental data for cation release from Li(Ni1/3Mn1/3Co1/3)O2 (NMC) nanoparticles in an aqueous environment ( Chem. Mater. 2016 (28) 1092-1100). To better understand the transformations that may occur when this material is exposed to the environment, we compute the free energy of surface dissolution, Δ G, from the complex metal oxide NMC for a range of surface terminations and pH.

Impact of Phosphate Adsorption on Complex Cobalt Oxide Nanoparticle Dispersibility in Aqueous Media.

A commonly overlooked and largely unknown aspect of assessing the environmental and biological safety of engineered nanomaterials is their transformation in aqueous systems. Complex metal oxides are an important class of materials for catalysis, energy storage, and water purification. However, the potential impact of nano complex metal oxides on the environment upon improper disposal is not well understood. We present a comprehensive analysis of the interaction of an environmentally relevant oxyanion, phosphate, with a complex metal oxide nanomaterial, lithium cobalt oxide. Our results show that adsorption of phosphate to the surface of these materials drastically impacts their surface charge, rendering them more stable in aqueous systems. The adsorbed phosphate remains on the surface over significant periods of time, suggesting that desorption is not kinetically favored. The implications of this interaction may be increased dispersibility and bioavailability of these materials in environmental water systems.

Analysis of the conformational properties of amine ligands at the gold/water interface with QM, MM and QM/MM simulations.

We describe a strategy of integrating quantum mechanical (QM), hybrid quantum mechanical/molecular mechanical (QM/MM) and MM simulations to analyze the physical properties of a solid/water interface. This protocol involves using a correlated ab initio (CCSD(T)) method to first calibrate Density Functional Theory (DFT) as the QM approach, which is then used in QM/MM simulations to compute relevant free energy quantities at the solid/water interface using a mean-field approximation of Yang et al. that decouples QM and MM thermal fluctuations; gas-phase QM/MM and periodic DFT calculations are used to determine the proper QM size in the QM/MM simulations. Finally, the QM/MM free energy results are compared with those obtained from MM simulations to directly calibrate the force field model for the solid/water interface. This protocol is illustrated by examining the orientations of an alkyl amine ligand at the gold/water interface, since the ligand conformation is expected to impact the chemical properties (e.g., charge) of the solid surface. DFT/MM and MM simulations using the INTERFACE force field lead to consistent results, suggesting that the effective gold/ligand interactions can be adequately described by a van der Waals model, while electrostatic and induction effects are largely quenched by solvation. The observed differences among periodic DFT, QM/MM and MM simulations, nevertheless, suggest that explicitly including electronic polarization and potentially charge transfer in the MM model can be important to the quantitative accuracy. The strategy of integrating multiple computational methods to cross-validate each other for complex interfaces is applicable to many problems that involve both inorganic/metallic and organic/biomolecular components, such as functionalized nanoparticles.