Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 100
Filtrar
1.
Nat Commun ; 15(1): 2573, 2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38519487

RESUMO

In two-dimensional chiral metal-halide perovskites, chiral organic spacers endow structural and optical chirality to the metal-halide sublattice, enabling exquisite control of light, charge, and electron spin. The chiroptical properties of metal-halide perovskites have been measured by transmissive circular dichroism spectroscopy, which necessitates thin-film samples. Here, by developing a reflection-based approach, we characterize the intrinsic, circular polarization-dependent complex refractive index for a prototypical two-dimensional chiral lead-bromide perovskite and report large circular dichroism for single crystals. Comparison with ab initio theory reveals the large circular dichroism arises from the inorganic sublattice rather than the chiral ligand and is an excitonic phenomenon driven by electron-hole exchange interactions, which breaks the degeneracy of transitions between Rashba-Dresselhaus-split bands, resulting in a Cotton effect. Our study suggests that previous data for spin-coated films largely underestimate the optical chirality and provides quantitative insights into the intrinsic optical properties of chiral perovskites for chiroptical and spintronic applications.

2.
Conserv Biol ; 38(1): e14160, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37551779

RESUMO

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.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , Estados Unidos , Humanos , México , Biodiversidade , Canadá
3.
Neuropharmacology ; 240: 109703, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37689262

RESUMO

The NMDA receptor (NMDAR) is a ubiquitously expressed glutamate-gated ion channel that plays key roles in brain development and function. Not surprisingly, a variety of disease-associated variants have been identified in genes encoding NMDAR subunits. A critical first step to assess whether these variants contribute to their associated disorder is to characterize their effect on receptor function. However, the complexity of NMDAR function makes this challenging, with many variants typically altering multiple functional properties. At synapses, NMDARs encode pre- and postsynaptic activity to carry a charge transfer that alters membrane excitability and a Ca2+ influx that has both short- and long-term signaling actions. Here, we characterized epilepsy-associated variants in GluN1 and GluN2A subunits with various phenotypic severity in HEK293 cells. To capture the complexity of NMDAR gating, we applied 10 glutamate pulses at 10 Hz to derive a charge integral. This assay is advantageous since it incorporates multiple gating parameters - activation, deactivation, and desensitization - into a single value. We then integrated this gating parameter with Mg2+ block and Ca2+ influx using fractional Ca2+ currents to generate indices of charge transfer and Ca2+ transfer over wide voltage ranges. This approach yields consolidated parameters that can be used as a reference to normalize channel block and allosteric modulation to better define potential patient treatment. This is especially true for variants in the transmembrane domain that affect not only receptor gating but also often Mg2+ block and Ca2+ permeation.

4.
J Biol Chem ; 299(10): 105227, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37673338

RESUMO

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.


Assuntos
Ácido Glutâmico , Multimerização Proteica , Receptores de AMPA , Ácido Glutâmico/metabolismo , Neurônios/metabolismo , Domínios Proteicos , Receptores de AMPA/química , Receptores de AMPA/genética , Transdução de Sinais , Subunidades Proteicas/química , Subunidades Proteicas/genética , Células HEK293 , Humanos
5.
bioRxiv ; 2023 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-36798164

RESUMO

AMPA receptor (AMPAR) auxiliary subunits are specialized, non-transient binding partners of AMPARs that modulate their ion 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) and cornichon homologs (CNIHs) and the more recently discovered GSG1-L. These auxiliary subunits can promote or reduce surface expression of AMPARs in neurons, thereby impacting their functional role in membrane signaling. Here, we show that CNIH-2 enhances the tetramerization of wild type and mutant AMPARs, possibly 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.

6.
Surg Oncol ; 51: 101895, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36682944

RESUMO

BACKGROUND: Increasing data suggests that the combination of modern systemic therapies and Cytoreductive surgery with or without Hyperthermic Intraperitoneal Chemotherapy (HIPEC) may improve the outcome of patients with colon cancer with peritoneal metastases. Patient selection and sequence of treatments remains ill-defined. MATERIALS AND METHODS: A working group, the State of Delaware Peritoneal Surface Malignancies Task Force (DE-PSM-TF), was created including representatives from medical and surgical oncology from the acute care hospitals in Delaware. An extensive review of all available literature was carried out. Virtual meetings were held, and interpretation and discussion of the data was conducted. RESULTS: A clinical pathway that includes a multidisciplinary evaluation at the time of diagnosis of colon cancer with peritoneal metastases and reflects a consensus from the Task Force on 7 key points that suggest the management of these patients based on the severity of their peritoneal metastases and incorporates all currently available therapies was created. The sequence of therapies of this multimodality treatment was determined by the Peritoneal Surface Disease Severity Score (PSDSS) (Fig. 1). CONCLUSION: The current pathway represents a comprehensive, team effort that should improve the outcome of patients with Colon Cancer with peritoneal metastases in the state of Delaware by having multidisciplinary discussions at the time of diagnosis, selecting the best order of sequence of currently available therapies in order to maximize benefits and minimize morbidity.


Assuntos
Neoplasias do Colo , Neoplasias Colorretais , Hipertermia Induzida , Neoplasias Peritoneais , Humanos , Neoplasias Peritoneais/secundário , Neoplasias Colorretais/patologia , Procedimentos Clínicos , Delaware , Prognóstico , Estudos Retrospectivos , Seguimentos , Neoplasias do Colo/terapia , Terapia Combinada , Procedimentos Cirúrgicos de Citorredução
7.
Adv Mater ; 35(15): e2211155, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36688433

RESUMO

Optomechanical reliability has emerged as an important criterion for evaluating the performance and commercialization potential of perovskite solar cells (PSCs) due to the mechanical-property mismatch of metal halide perovskites with other device layer. In this work, grain-boundary grooves, a rarely discussed film microstructural characteristic, are found to impart significant effects on the optomechanical reliability of perovskite-substrate heterointerfaces and thus PSC performance. By pre-burying iso-butylammonium chloride additive in the electron-transport layer (ETL), GB grooves (GBGs) are flattened and an optomechanically reliable perovskite heterointerface that resists photothermal fatigue is created. The improved mechanical integrity of the ETL-perovskite heterointerfaces also benefits the charge transport and chemical stability by facilitating carrier injection and reducing moisture or solvent trapping, respectively. Accordingly, high-performance PSCs which exhibit efficiency retentions of 94.8% under 440 h damp heat test (85% RH and 85 °C), and 93.0% under 2000 h continuous light soaking are achieved.

8.
Conserv Biol ; 37(3): e14048, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36661081

RESUMO

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.


Assuntos
Biodiversidade , Conservação dos Recursos Naturais , Mudança Climática , Incerteza , Ecossistema
9.
Cureus ; 15(12): e50536, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38222137

RESUMO

Mantle cell lymphoma (MCL) most commonly presents as lymphadenopathy (LAD), fevers, night sweats, weight loss, splenomegaly, and blood count abnormalities. While extranodal involvement as an initial presentation can occur, it is uncommon. At initial diagnosis, MCL most commonly presents as widespread, advanced stage III or IV lymphoma. Given advanced stage MCL at presentation, it is important for medical practitioners to recognize unusual extranodal presentations of MCL for earlier diagnosis and treatment planning. Here, we present a case of MCL initially presenting as cholecystitis and bilateral nephromegaly in a 53-year-old male patient.

10.
Phys Rev Lett ; 129(6): 065501, 2022 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-36018671

RESUMO

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.

11.
J Appl Ecol ; 59(3): 653-663, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35873077

RESUMO

Neotropical countries receive financing and effort from temperate nations to aid the conservation of migratory species that move between temperate and tropical regions. If allocated strategically, these resources could simultaneously contribute to other conservation initiatives. In this study, we use novel distribution maps to show how those resources could aid planning for the recovery of threatened resident vertebrates.Using eBird-based relative abundance estimates, we first identified areas with high richness of Neotropical migrant landbirds of conservation concern (23 species) during the stationary non-breeding period. Within these areas, we then identified threatened species richness, projected forest loss and conducted a prioritization for 1,261 red-listed vertebrates using Terrestrial Area-of-Habitat maps.Richness for migrants was greatest along a corridor from the Yucatan peninsula south to the northern Andes but also included south-west Mexico and Hispaniola. Protected areas account for 22% of this region while 21% is at risk of forest loss. Within this focal region for migrants, all four vertebrate groups showed hotspots of threatened species richness along the west and east Andean slopes. Taxa-specific hotspots included montane areas of southern Mexico and central Guatemala (amphibians/reptiles) and the entire east slope of the Colombian East Andes (mammals).Our prioritization highlighted several areas of importance for conservation due to high threatened species richness and projected forest loss including (a) the Pacific dry forests of south-west Mexico, (b) montane regions of northern Central America and (c) the west Andean slope of Colombia and Ecuador. At a landscape scale in southern Colombia, we show how conservation efforts for six Neotropical migrants could benefit 56 threatened residents that share a similar elevational range. Synthesis and applications. Funding and effort for migratory bird conservation also has potential to benefit threatened resident vertebrates in the Neotropics. Our study highlights how novel, high-resolution information on species distributions and risk of forest loss can be integrated to identify priority areas for the two groups at regional and landscape scales. The approach and data can be further modified for more specific goals, such as within-country initiatives.


Los países neotropicales reciben financiamiento y recursos esfuerzos de países templados para ayudar a la conservación de las aves migratorias que se mueven entre estas dos regiones. Si se asignan estratégicamente, estos recursos podrían beneficiar simultáneamente a otras iniciativas de conservación. En esta investigación, usamos novedosos mapas de distribución para mostrar cómo esos recursos podrían ayudar a planificar la conservación de especies residentes amenazadas.Utilizando estimaciones de abundancia de eBird, delineamos la Región Focal con la mayor riqueza de aves migratorias neotropicales de interés para la conservación durante el periodo invernal (23 especies). Dentro de esta región, determinamos la riqueza de especies residentes amenazadas, la proyección de pérdida de bosque, y realizamos una priorización para 1261 especies de vertebrados incluidos en la lista roja de la IUCN utilizando mapas del área de hábitat terrestre.En la Región Focal, la riqueza de aves migratorias fue mayor a lo largo de un corredor desde el sur de la península de Yucatán hasta el norte de los Andes, y en el suroeste de México y la isla La Española. Las áreas protegidas representan 22% de esta región mientras que el 21% está en riesgo de pérdida de bosque. Dentro de la Región Focal para las aves migratorias, todos los vertebrados residentes mostraron puntos de mayor riqueza de especies amenazadas en los Andes occidentales y orientales. Las regiones con mayor riqueza para taxones específicos incluyeron las montañas del sur de México y del centro de Guatemala (anfibios y reptiles) y la vertiente oriental de la cordillera oriental de Colombia (mamíferos).La priorización destacó varias áreas de importancia para la conservación debido a la alta riqueza de especies amenazadas y a la pérdida de bosque proyectada incluyendo 1) los bosques secos del Pacífico del suroeste de México, 2) las regiones montañosas del norte de Centroamérica y 3) la vertiente occidental de los Andes Occidental de Colombia y Ecuador. A escala del paisaje en el sur de Colombia, mostramos cómo los esfuerzos para la conservación de 6 aves migratorias podrían beneficiar a 56 especies residentes amenazadas que comparten un rango altitudinal similar. Síntesis y aplicaciones. La financiación y esfuerzos para la conservación de las aves migratorias tienen el potencial a beneficiar a los vertebrados residentes amenazados en el Neotrópico. Nuestro estudio resalta como se puede integrar información novedosa y de alta resolución acerca de la distribución de especies y el riesgo de pérdida de bosques para identificar áreas prioritarias para los dos grupos a escala regional y paisajística. El enfoque y los datos se pueden modificar para objetivos más específicos, como por ejemplo iniciativas dentro de cada país.

12.
Exp Gerontol ; 163: 111803, 2022 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-35413409

RESUMO

INTRODUCTION: Many falls in older adults are due to a loss of mediolateral stability during gait. This investigation examines if a simple beam-walking task can assess fall risk in older adults by taxing mediolateral control during gait. MATERIAL AND METHODS: 50 older adults (65-96 yrs.) and 20 younger adults (20-35 yrs.) walked along three 6 m long beams (12, 9 and 6 cm wide). Distance walked, number of steps and velocity were recorded. Participants also completed the Narrow Path Walking Test on a computerized gait mat and walked unrestricted across the mat. The number of falls in the 6 months pre- and post-testing were recorded. RESULTS: The beam data revealed significant differences between fallers and non-fallers in distance walked and number of steps taken on the 9 cm beam but not on the other beam widths. The coefficient of variation (CV) for step time and step length for unrestricted walking and for the NPWT were also significantly different between fallers and non-fallers. Falls in the 6 months before testing was not correlated with gait velocity but was significantly correlated with the number of steps and the distance walked on the 9 cm beam and with step length and step time CV. Falls in the 6 months following testing were strongly correlated with distance walked on the 9 cm beam. CONCLUSION: This research suggests that examining an older adult's ability to walk on a 9 cm wide beam might contribute significantly to the assessment of that person's fall risk.


Assuntos
Marcha , Caminhada , Acidentes por Quedas/prevenção & controle , Idoso , Suscetibilidade a Doenças , Humanos , Teste de Caminhada
13.
ACS Appl Mater Interfaces ; 14(11): 13858-13871, 2022 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-35258292

RESUMO

Humans have incorporated minerals in objects of cultural heritage importance for millennia. The surfaces of these objects, which often long outlast the humans that create them, are undeniably exposed to a diverse mixture of chemicals throughout their lifetimes. As of yet, the art conservation community lacks a nondestructive, accurate, and inexpensive flexible computational screening method to evaluate the potential impact of chemicals with art, as a complement to experimental studies. In this work, we propose periodic density functional theory (DFT) studies as a way to address this challenge, specifically for the aragonite phase of calcium carbonate, a mineral that has been used in pigments, marble statues, and limestone architecture since ancient times. Computational models allow art conservation scientists to better understand the atomistic impact of small-molecule adsorbates on common mineral surfaces across a wide variety of environmental conditions. To gain insight into the surface adsorption reactivity of aragonite, we use DFT to investigate the atomistic interactions present in small-molecule-surface interfaces. Our adsorbate set includes common solvents, atmospheric pollutants, and emerging contaminants. Chemicals that significantly disrupt the surface structure such as carboxylic acids and sulfur-containing molecules are highlighted. We also focus on comparing adsorption energies and changes in surface bonds, which allows for the identification of key features in the electronic structure presented in a projected-density-of-state analysis. The trends outlined here will guide future experiments and allow art conservators to gain a better understanding of how a wide range of molecules interact with an aragonite surface under variable conditions and in different environments.

14.
Environ Evid ; 11(1): 3, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35136590

RESUMO

BACKGROUND: Altering the natural flow regime, an essential component of healthy fluvial systems, through hydropower operations has the potential to negatively impact freshwater fish populations. Establishing improved management of flow regimes requires better understanding of how fish respond to altered flow components, such as flow magnitude. Based on the results of a recent systematic map on the impacts of flow regime changes on direct outcomes of freshwater or estuarine fish productivity, evidence clusters on fish abundance and biomass responses were identified for full systematic review. The primary goal of this systematic review is to address one of those evidence clusters, with the following research question: how do changes in flow magnitude due to hydropower operations affect fish abundance and biomass? METHODS: This review follows the guidelines of the Collaboration for Environmental Evidence. It examined commercially published and grey literature originally identified during the systematic map process and a systematic search update. All articles were screened using an a priori eligibility criteria at two stages (title and abstract, and full-text) and consistency checks were performed at all stages. All eligible articles were assessed for study validity and specifically designed data extraction and study validity tools were used. A narrative synthesis included all available evidence and meta-analysis using the standardized mean difference (Hedges' g) was conducted where appropriate. REVIEW FINDINGS: A total of 133 studies from 103 articles were included in this systematic review for data extraction and critical appraisal. Most studies were from North America (60%) and were conducted at 146 different hydropower dams/facilities. Meta-analysis included 268 datasets from 58 studies, separated into three analyses based on replication type [temporal (within or between year replication) or spatial]. Fish abundance (226 datasets) and biomass (30 datasets) had variable responses to changes in flow magnitude with estimated overall mean effect sizes ranging from positive to negative and varying by study design and taxa. In studies with temporal replication, we found a detectable effect of alterations to the direction of flow magnitude, the presence of other flow components, sampling methods, season, and fish life stage. However, we found no detectable effect of these moderators for studies with spatial replication. Taxonomic analyses indicated variable responses to changes in flow magnitude and a bias towards salmonid species. CONCLUSIONS: This synthesis did not find consistent patterns in fish abundance or biomass responses to alterations or changes in flow magnitude. Fish responses to flow magnitude alterations or changes were highly variable and context dependent. Our synthesis suggests that biotic responses may not be generalizable across systems impacted by hydroelectric power production and operations, where specific features of the system may be highly influential. Site-specific and adaptive management may be necessary. To improve study validity and interpretability, studies with long-term continuous monitoring, and both temporal and spatial replication are needed. When this gold standard is unfeasible, studies should strive, at minimum, to maximize replication within both intervention and comparator groups for either temporal or spatial designs. To further address knowledge gaps, studies are needed that focus on non-salmonids, multiple seasons, and systems outside of North America. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13750-021-00254-8.

15.
Conserv Biol ; 36(3): e13835, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-34476839

RESUMO

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.


Assuntos
Biodiversidade , Conservação dos Recursos Naturais , Humanos , Pesquisadores
16.
Ecol Evol ; 11(16): 11275-11281, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34429917

RESUMO

Knowing the distribution of migratory species at different stages of their life cycle is necessary for their effective conservation. For the Monarch butterfly (Danaus plexippus), although its overwintering distribution is well known, the available information on premigration distribution is limited to the studies estimating the natal origins of overwintering Monarchs in Mexico (i.e., postmigration data). However, the premigration distribution and the natal origins of overwintering Monarchs can be equivalent only if we assume that migrating Monarchs have the same mortality rate irrespective of their origins. To estimate Monarchs' premigration distribution, we used data reported by community scientists before Monarchs start their fall migration, that is, before migration mortality, and controlled for sampling bias. Our premigration distribution map indicated that Minnesota, Texas, and Ontario are the states/provinces with the highest abundance of Monarch in North America. Although this higher estimated abundance can be related to the large sizes of these states/provinces, this information is still important because it identifies the management jurisdictions with the largest responsibility for the conservation of the premigration population of Monarchs. Our premigration distribution map will be useful in future studies estimating the rates, distribution, and causes of mortality in migrating Monarchs.

17.
Glob Chang Biol ; 27(19): 4799-4824, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34289527

RESUMO

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.


Assuntos
Mudança Climática , Peixes , Animais , Conservação dos Recursos Naturais , Ecossistema , Pesqueiros , Água Doce
18.
Surg Oncol ; 37: 101319, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34103239

RESUMO

BACKGROUND: Pancreatic tumors are frequently found in a geriatric population. Given that the median age of patients with pancreatic cancer is 70 years at diagnosis and the ubiquity of CT and MRI imaging has increased the detection of pancreas masses, pancreatic surgeons often find themselves operating on patients of advanced age. This study sought to evaluate the outcomes of pancreatic resection in an octogenarian population at a single institution with a dedicated surgical oncology team. STUDY DESIGN: A retrospective chart review was performed for all patients undergoing pancreatic resection over a 13-year period at an academic community cancer center. Patient characteristics and operative outcomes were compared between patients aged 80 and older, and those younger than 80. Student t-tests, Fisher's exact test, and Kruskal-Wallis tests were used for univariate analyses. RESULTS: Over the 13-year period, a total of 48 patients of 403 undergoing pancreatic resections were aged 80 or older. Of these 48 patients, 35 underwent pancreaticoduodenectomy (Whipple) and 13 underwent distal pancreatectomy. Patient characteristics including ASA classification were similar among the two age groups. The procedures themselves were equally complicated with similar operative times, transfusion requirements, estimated blood losses, and portal vein resections. The number and severity of complications such as delayed gastric emptying and pancreatic leak were not statistically different between the two groups. Additionally, the 30-day reoperation, readmission, and mortality rates were not statistically different. Outcomes at 90-days revealed an increased rate of readmission amongst octogenarians who underwent Whipple without an increase in rates of major complications. The total number of deaths in the octogenarian group was 3 (6.2%) vs. 6 (1.7%) in the non-octogenarian group (p = 0.080). The median length of stay was similar amongst the two age groups. CONCLUSIONS: At a large-volume academic community cancer center with a dedicated surgical oncology team, highly selected octogenarians can undergo pancreatic resection safely with outcomes that do not differ significantly from their younger counterparts.


Assuntos
Pancreatectomia/estatística & dados numéricos , Neoplasias Pancreáticas/epidemiologia , Neoplasias Pancreáticas/cirurgia , Pancreaticoduodenectomia/métodos , Pancreaticoduodenectomia/estatística & dados numéricos , Adenocarcinoma/patologia , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Maryland/epidemiologia , Pancreatectomia/efeitos adversos , Pancreatectomia/métodos , Neoplasias Pancreáticas/patologia , Pancreaticoduodenectomia/efeitos adversos , Complicações Pós-Operatórias/epidemiologia , Estudos Retrospectivos , Resultado do Tratamento
19.
Am J Surg ; 222(5): 983-988, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33933208

RESUMO

BACKGROUND: Gastrointestinal Stromal Tumors (GISTs) are rare sarcomas with 5000 new cases arising in the United States each year. Despite their low incidence, general surgeons should be familiar with GISTs since a quarter of these neoplasms are encountered incidentally. METHODS: A retrospective medical records review was conducted to create a database of all GISTs resected from January 2005 to May 2019. We isolated patients who had incidental discovery of GISTs intraoperatively or within final pathology. Characteristics of patient (Age, gender), index procedure (malignant vs. benign, elective vs. emergent) and tumor (location, size and mitotic rate) were analyzed. RESULTS: A total 48 patients were incidentally discovered to have a GIST excised during index operation. The mean age of these patients was 62 years, with 27 females and 21 males. The primary location of tumors in descending frequency was stomach (30), small bowel (15), colon/rectum (2) and esophagus (1). The average size of all tumors was 1.2 cm, with the average size of the stomach, small bowel, colon/rectum and esophagus at 0.9 cm, 1.7 cm, 0.9 cm and 0.3 cm respectively. Mitotic rate was less than 5 mitosis per 50 HPF in 96% of patients. Incidental tumors were identified during both bariatric (13) and non-bariatric stomach surgery (8), colorectal surgery (14), hernia repair (4), ampullary/pancreatic surgery (5), esophageal surgery (2) liver surgery (1) and uterine surgery (1). Most incidental-GISTs were identified during elective surgery (81%, 39). Finally, 15 of the tumors were identified during surgery for other malignancies. CONCLUSIONS: One quarter (25%) of the GISTs encountered at our academic community cancer center over a 15-year period were discovered incidentally. These tumors had less malignant characteristics overall and were likely cured with surgical resection.


Assuntos
Neoplasias Gastrointestinais/diagnóstico , Tumores do Estroma Gastrointestinal/diagnóstico , Achados Incidentais , Neoplasias Gástricas/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Gastrectomia/estatística & dados numéricos , Neoplasias Gastrointestinais/patologia , Tumores do Estroma Gastrointestinal/patologia , Humanos , Masculino , Pessoa de Meia-Idade
20.
Proc Natl Acad Sci U S A ; 118(18)2021 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-33903229

RESUMO

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.


Assuntos
Ascomicetos/enzimologia , Biopolímeros/química , Enzimas/química , Lignina/química , Ascomicetos/química , Biopolímeros/metabolismo , Enzimas/genética , Flavonoides/química , Lignina/metabolismo , Oxirredução , Oxirredutases/química , Oxirredutases/genética , Oxigenases/química , Especificidade por Substrato/genética , Triticum/enzimologia , Triticum/microbiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA