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1.
Proc Natl Acad Sci U S A ; 121(25): e2321479121, 2024 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-38857393

RESUMEN

Conservation enforcement is a direct strategy to combat illegal wildlife trade in open markets. Yet, its large-scale effectiveness has not been widely assessed due to the lack of extensive market data. Between August 2016 and June 2017, a national coordinated enforcement campaign led by the leading Chinese authority to combat illegal migratory bird trade coincided with the largest-ever pet bird market survey across China by voluntary birdwatchers before and after the enforcement, which served as a unique natural experiment. Across 73 markets from 22 Chinese provinces, the dataset contains 140,723 birds of 346 species from 48 families and recorded a drastic decline in bird abundance traded after enforcement. Notably, species protected under China's Wildlife Protection Law declined significantly, while commercially bred species increased, although responses to enforcement were spatially heterogeneous. Our model showed that the national protection level was the best predictor for the trend of traded species, even after accounting for confounding factors such as regional baseline enforcement pressure and wild native bird populations. However, the widely traded native songbirds were not offered adequate national protection. Future policies should consider the pet bird trade patterns, target key areas of trade, and develop a more systematic market survey design to monitor trade.


Asunto(s)
Aves , Comercio , Conservación de los Recursos Naturales , Aplicación de la Ley , Mascotas , Animales , China , Comercio/legislación & jurisprudencia , Conservación de los Recursos Naturales/legislación & jurisprudencia , Animales Salvajes
2.
PLoS Biol ; 21(7): e3002166, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37410698

RESUMEN

Birds share lands with humans at a substantial scale and affect crops. Yet, at a global scale, systematic evaluations of human-bird coexistence in croplands are scarce. Here, we compiled and used meta-analysis approaches to synthesize multiple global datasets of ecological and social dimensions to understand this complex coexistence system. Our result shows that birds usually increase woody, but not herbaceous, crop production, implying that crop loss mitigation efforts are critical for a better coexistence. We reveal that many nonlethal technical measures are more effective in reducing crop loss, e.g., using scaring devices and changing sow practices, than other available methods. Besides, we find that stakeholders from low-income countries are more likely to perceive the crop losses caused by birds and are less positive toward birds than those from high-income ones. Based on our evidence, we identified potential regional clusters, particularly in tropical areas, for implementing win-win coexistence strategies. Overall, we provide an evidence-based knowledge flow and solutions for stakeholders to integrate the conservation and management of birds in croplands.


Asunto(s)
Agricultura , Aves , Humanos , Animales , Femenino , Porcinos , Agricultura/métodos , Productos Agrícolas , Conservación de los Recursos Naturales/métodos
3.
Proc Natl Acad Sci U S A ; 119(23): e2202189119, 2022 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-35653574

RESUMEN

SignificanceSemiconductor interfaces are among the most important in use in modern technology. The properties they exhibit can either enable or disable the characteristics of the materials they connect for functional performance. While much is known about important junctions involving conventional semiconductors such as Si and GaAs, there are several unsolved mysteries surrounding interfaces between oxide semiconductors. Here we resolve a long-standing issue concerning the measurement of anomalously low dielectric constants in SrTiO3 films with record high electron mobilities. We show that the junction between doped and undoped SrTiO3 required to make dielectric constant measurements masks the dielectric properties of the undoped film. Through modeling, we extract the latter and show that it is much higher than previously measured.

4.
Proc Natl Acad Sci U S A ; 119(4)2022 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-35042814

RESUMEN

We unravel the interplay of topological properties and the layered (anti)ferromagnetic ordering in EuSn2P2, using spin and chemical selective electron and X-ray spectroscopies supported by first-principle calculations. We reveal the presence of in-plane long-range ferromagnetic order triggering topological invariants and resulting in the multiple protection of topological Dirac states. We provide clear evidence that layer-dependent spin-momentum locking coexists with ferromagnetism in this material, a cohabitation that promotes EuSn2P2 as a prime candidate axion insulator for topological antiferromagnetic spintronics applications.

5.
Phys Rev Lett ; 132(19): 196201, 2024 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-38804932

RESUMEN

We report the quantitative adsorption structure of pristine graphene on Cu(111) determined using the normal incidence x-ray standing wave technique. The experiments constitute an important benchmark reference for the development of density functional theory approximations able to capture long-range dispersion interactions. Electronic structure calculations based on many-body dispersion-inclusive density functional theory are able to accurately predict the absolute measure and variation of adsorption height when the coexistence of multiple moiré superstructures is considered. This provides a structural model consistent with scanning probe microscopy results.

6.
Conserv Biol ; 38(5): e14351, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39248759

RESUMEN

Unsustainable wildlife consumption and illegal wildlife trade (IWT) threaten biodiversity worldwide. Although publicly accessible data sets are increasingly used to generate insights into IWT, little is known about their potential bias. We compared three typical and temporally corresponding data sets (4204 court verdicts, 926 seizure news reports, and 219 bird market surveys) on traded birds native to China and evaluated their possible species biases. Specifically, we evaluated bias and completeness of sampling for species richness, phylogeny, conservation status, spatial distribution, and life-history characteristics among the three data sets when determining patterns of illegal trade. Court verdicts contained the largest species richness. In bird market surveys and seizure news reports, phylogenetic clustering was greater than that in court verdicts, where songbird species (i.e., Passeriformes) were detected in higher proportions in market surveys. The seizure news data set contained the highest proportion of species of high conservation priority but the lowest species coverage. Across the country, all data sets consistently reported relatively high species richness in south and southwest regions, but markets revealed a northern geographic bias. The species composition in court verdicts and markets also exhibited distinct geographical patterns. There was significant ecological trait bias when we modeled whether a bird species is traded in the market. Our regression model suggested that species with small body masses, large geographical ranges, and a preference for anthropogenic habitats and those that are not nationally protected were more likely to be traded illegally. The species biases we found emphasize the need to know the constraints of each data set so that they can optimally inform strategies to combat IWT.


Cuantificación del sesgo por especies entre fuentes de datos múltiples para el mercado ilegal de fauna y lo que implica para la conservación Resumen El consumo insostenible y el comercio ilegal de fauna y flora silvestres amenazan la biodiversidad en todo el mundo. Aunque los conjuntos de datos de acceso público se utilizan cada vez más para obtener información sobre el mercado ilegal de especies silvestres, se sabe poco sobre su posible sesgo. Comparamos tres conjuntos de datos típicos con correspondencia temporal (4,204 sentencias judiciales, 926 informes de noticias sobre incautaciones y 219 encuestas sobre mercados de aves) de aves autóctonas de China objeto de comercio y evaluamos sus posibles sesgos por especie. En concreto, evaluamos el sesgo y la exhaustividad del muestreo de la riqueza de especies, la filogenia, el estado de conservación, la distribución espacial y las características del ciclo vital entre los tres conjuntos de datos a la hora de determinar los patrones del mercado ilegal. Las sentencias judiciales contenían la mayor riqueza de especies. En los estudios de mercado de aves y en los informes de noticias sobre incautaciones, la agrupación filogenética fue mayor que en las sentencias judiciales, donde las especies de aves canoras (Passeriformes) se detectaron en mayor proporción en los estudios de mercado. El conjunto de datos de noticias sobre decomisos contenía la mayor proporción de especies de alta prioridad para la conservación, pero la menor cobertura de especies. En todo el país, todos los conjuntos de datos informaron sistemáticamente de una riqueza de especies relativamente alta en las regiones sur y suroeste, pero los mercados revelaron un sesgo geográfico septentrional. La composición por especies en los veredictos judiciales y en los mercados también mostró patrones geográficos distintos. Hubo un sesgo significativo de rasgos ecológicos cuando modelamos si una especie de ave se comercializa en el mercado. Nuestro modelo de regresión sugería que las especies con masas corporales pequeñas, grandes áreas de distribución geográfica y preferencia por los hábitats antropogénicos y las especies que no están protegidas a nivel nacional tenían más probabilidades de ser objeto de comercio ilegal. Los sesgos de las especies que hallamos resaltan la necesidad de conocer las limitaciones de cada conjunto de datos para poder informar de manera óptima las estrategias de lucha contra el comercio ilegal de especies silvestres.


Asunto(s)
Biodiversidad , Aves , Comercio , Conservación de los Recursos Naturales , Conservación de los Recursos Naturales/legislación & jurisprudencia , Animales , China , Comercio/legislación & jurisprudencia , Crimen/estadística & datos numéricos , Animales Salvajes , Filogenia , Comercio de Vida Silvestre
7.
Conserv Biol ; 38(5): e14352, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39248772

RESUMEN

Illegal poaching and overexploitation for the international pet trade are among the greatest threats to freshwater turtles in Southeast Asia. Expanding consumer research in China is crucial to filling knowledge gaps about the scale and structure of illegal trade and developing audience-targeted and relevant interventions that may reduce demand for illegal turtles as pets. We applied mixed methods to provide a detailed understanding of the consumer side of the illegal pet turtle trade in China. We conducted 30 interviews with key stakeholders and online surveys (n = 2456) of turtle keepers via community forums. From these, we identified 3 core consumer groups based on their prior turtle-keeping experience, species exposure, and potential for future purchases. We conducted a thematic qualitative analysis of concepts related to the capability, opportunity, motivation, and behavior (COM-B) model to determine the factors influencing the illegal pet turtle trade and to identify barriers to illegal purchases. Specifically, we identified purchasers' capabilities, opportunities, and motivations in the context of legality, enforcement risk, captive breeding, and impacts on wild population. We developed consumer journey maps (i.e., visual representations of customer's experiences throughout their buying journey) for core consumer groups. These maps illustrate the sequential behaviors and processes that consumers undertake when purchasing turtles, from initial exposure to sourcing, keeping, and providing a new home. Key factors influencing illegal purchases included convenient purchase channels, misguided cognition and motivations for pet keeping, and weak law enforcement. Effective interventions included messages focusing on shifting cognition and beliefs, increasing legal risk perception, and emphasizing stringent law enforcement, primarily delivered through online channels. Our results underscore the necessity for adaptable, audience-tailored interventions to reduce consumer demand for illegal wildlife products. The mixed-methods approach, combining quantitative and qualitative data, provided a comprehensive understanding of the target behavior and can inform the development of effective intervention strategies.


Uso de las percepciones del consumidor para guiar las intervenciones de cambio conductual enfocadas en el mercado ilegal de tortugas en China Resumen La caza furtiva y la sobreexplotación por el comercio internacional de mascotas son algunas de las mayores amenazas para las tortugas de agua dulce del sudeste asiático. Es esencial conocer más sobre los consumidores en China para llenar los vacíos en el conocimiento sobre la escala y la estructura del comercio ilegal y desarrollar intervenciones pertinentes y dirigidas al público que puedan reducir la demanda de tortugas como mascotas ilegales. Aplicamos métodos mixtos para conocer en detalle la percepción del consumidor del comercio ilegal de tortugas como mascotas en China. Realizamos 30 entrevistas a actores clave y encuestas en línea (n=2456) a cuidadores de tortugas a través de foros comunitarios. A partir de ellas, identificamos tres grupos principales de consumidores en función de su experiencia previa en la cría de tortugas, su exposición a las especies y su potencial para futuras compras. Realizamos un análisis cualitativo temático de conceptos relacionados con el modelo de capacidad, oportunidad, motivación y comportamiento (COM­B) para determinar los factores que influyen en el comercio ilegal de tortugas e identificar las barreras para las compras ilegales. En concreto, identificamos las capacidades, oportunidades y motivaciones de los compradores en el contexto de la legalidad, el riesgo de aplicación de la ley, la cría en cautiverio y el impacto sobre la población silvestre. Elaboramos mapas de viaje del consumidor (representaciones visuales de las experiencias del cliente a lo largo de su compra) para los principales grupos de consumidores. Estos mapas ilustran los comportamientos y procesos secuenciales que llevan a cabo los consumidores cuando compran tortugas, desde la exposición inicial hasta la adquisición, el mantenimiento y la asignación de un nuevo hogar. Entre los factores clave que influyen en las compras ilegales se encuentran la conveniencia de los canales de compra, los conocimientos y motivaciones erróneos para mantener mascotas y la debilidad de la aplicación de la ley. Las intervenciones eficaces incluyeron mensajes centrados en cambiar los conocimientos y las creencias, aumentar la percepción del riesgo legal y hacer hincapié en la aplicación rigurosa de la ley, principalmente a través de canales virtuales. Nuestros resultados destacan la necesidad de intervenciones adaptables y adaptadas al público para reducir la demanda de productos ilegales de fauna silvestre por parte de los consumidores. El enfoque de métodos mixtos, que combina datos cuantitativos y cualitativos, proporcionó una comprensión exhaustiva del comportamiento objetivo y puede servir de base para el desarrollo de estrategias de intervención eficaces.


Asunto(s)
Comercio , Conservación de los Recursos Naturales , Mascotas , Tortugas , Tortugas/fisiología , Animales , China , Conservación de los Recursos Naturales/legislación & jurisprudencia , Mascotas/psicología , Comportamiento del Consumidor , Humanos
8.
BMC Pulm Med ; 24(1): 164, 2024 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-38575978

RESUMEN

BACKGROUND: This study aimed to compare patient experiences during bronchoscopy procedures using either topical anesthesia (TA) or monitored anesthesia care (MA). The goal was to identify circumstances where patients could achieve similar levels of tolerance and satisfaction using only TA, especially in resource-limited settings. METHODS: This study included consecutive patients who underwent bronchoscopy with either TA or MA. Data collected included demographics, indications for bronchoscopy, procedure time, and complications during the procedure. A quality assurance survey was administered to assess patient experience and satisfaction with both procedures. A pre-specified subgroup analysis was performed based on procedure invasiveness and time. RESULTS: This study enrolled 350 (TA 251; MA 99) patients, with an average age of 65 years. Main indications for bronchoscopy included tumor diagnosis (38%), esophageal cancer staging (18%), and pulmonary infection (17%). The average duration of the procedures was 20 min, with MA being associated with a significantly longer procedure time than TA (31 min vs. 16 min; P < 0.001). The overall satisfaction rating with bronchoscopy was significantly higher in the MA group (visual analogue scale, 8.9 vs. 8.2; P = 0.001). Subgroup analyses showed that when less invasive or shorter procedures were performed, TA patients reported tolerance and satisfaction levels comparable to MA patients. CONCLUSIONS: Bronchoscopy with MA offered patients a better experience and greater satisfaction; however, in settings with limited resources, TA alone may provide similar levels of patient tolerance and satisfaction during less invasive or shorter procedures.


Asunto(s)
Anestesia , Neumonía , Humanos , Anciano , Broncoscopía/métodos , Dimensión del Dolor , Evaluación del Resultado de la Atención al Paciente , Satisfacción del Paciente
9.
Int J Mol Sci ; 25(12)2024 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-38928145

RESUMEN

Polyurethane (PU) is a promising material for addressing challenges in bone grafting. This study was designed to enhance the bone grafting capabilities of PU by integrating hydroxyapatite (HAp), which is known for its osteoconductive and osteoinductive potential. Moreover, a uniform distribution of HAp in the porous structure of PU increased the effectiveness of bone grafts. PEG/APTES-modified scaffolds were prepared through self-foaming reactions. A uniform pore structure was generated during the spontaneous foaming reaction, and HAp was uniformly distributed in the PU structure (PU15HAp and PU30HAp) during foaming. Compared with the PU scaffolds, the HAp-modified PU scaffolds exhibited significantly greater protein absorption. Importantly, the effect of the HAp-modified PU scaffold on bone repair was tested in a rat calvarial defect model. The microstructure of the newly formed bone was analyzed with microcomputed tomography (µ-CT). Bone regeneration at the defect site was significantly greater in the HAp-modified PU scaffold group than in the PU group. This innovative HAp-modified PU scaffold improves current bone graft materials, providing a promising avenue for improved bone regeneration.


Asunto(s)
Regeneración Ósea , Durapatita , Poliuretanos , Cráneo , Andamios del Tejido , Poliuretanos/química , Animales , Durapatita/química , Andamios del Tejido/química , Ratas , Regeneración Ósea/efectos de los fármacos , Cráneo/efectos de los fármacos , Cráneo/lesiones , Cráneo/patología , Cráneo/metabolismo , Ratas Sprague-Dawley , Microtomografía por Rayos X , Masculino , Porosidad , Trasplante Óseo/métodos
10.
Opt Express ; 31(3): 4281-4290, 2023 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-36785400

RESUMEN

A tapered bus-waveguide is demonstrated to enhance the waveguide-to-cavity coupling by mass-productive, cost-effective i-line UV lithography. Through enlarging the overlap between the evanescent wave and waveguide resonator, we experimentally show that the coupling strength of silicon nitride waveguides can be 7 times stronger than the conventional coupling of a uniform, straight bus-waveguide. For the first time, strong over-coupling is identified at a 400 nm gap and quality factor ≈ 105 without elongating the coupling length. This design relieves the fabrication limits and provides the flexibility for coupling control, especially in the strongly over-coupled regime with i-line UV lithography.

11.
Diabetes Metab Res Rev ; 39(3): e3603, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36579718

RESUMEN

AIMS: Type 2 diabetes mellitus (T2DM) frequently co-exists with osteoporosis and dyslipidemia. Statins have been commonly used in the treatment of dyslipidemia. Recent studies have indicated a therapeutic role of statins in decreasing the risk of osteoporosis and fractures, but conflicting results have been reported. This study investigated the association between statin use and hip fracture (HFx) risk among T2DM patients. MATERIALS AND METHODS: A retrospective Taiwan population-based propensity-matched cohort study was performed using the Diabetes Mellitus Health Database from Taiwan National Health Insurance Research Database. Patients with newly diagnosed with T2DM between 2010 and 2014 were identified. Patients who previously used statins and had ever suffered HFx before the index date were excluded. HFx that occurred from 2010 to 2019 was collected to compute the cumulative rate of HFx. Hazard ratios (HRs) were calculated for the HFx risk according to the use or non-use of statins. To evaluate the dose-effect relationship of statins, sensitivity analyses were conducted. RESULTS: After propensity score matching for age and sex, 188,588 patients were identified as statin users and non-statin users. Statin use after T2DM diagnosis was associated with a decreased HFx risk with an adjusted HR (aHR) of 0.69 (P < 0.001). A dose-effect relationship was identified. The aHRs for developing HFx were 1.29, 0.67, and 0.36 for patients who used 28-174, 175-447, and >447 cumulative defined daily doses of statins, respectively (P < 0.001). CONCLUSIONS: Statin use in adults with T2DM showed a lower risk of HFx by demonstrating a dose-response relationship.


Asunto(s)
Diabetes Mellitus Tipo 2 , Dislipidemias , Fracturas de Cadera , Inhibidores de Hidroximetilglutaril-CoA Reductasas , Osteoporosis , Adulto , Humanos , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/inducido químicamente , Estudios Retrospectivos , Estudios de Cohortes , Inhibidores de Hidroximetilglutaril-CoA Reductasas/uso terapéutico , Taiwán/epidemiología , Osteoporosis/inducido químicamente , Osteoporosis/complicaciones , Osteoporosis/tratamiento farmacológico , Dislipidemias/complicaciones , Dislipidemias/tratamiento farmacológico , Dislipidemias/epidemiología , Fracturas de Cadera/epidemiología , Fracturas de Cadera/etiología , Fracturas de Cadera/prevención & control , Factores de Riesgo
12.
Conserv Biol ; 37(4): e14055, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-36864722

RESUMEN

Internet trade is increasingly recognized as a dispersal pathway of non-native plant species that is difficult to monitor. We sought to identify non-native flora present in the Chinese online market, the largest e-commerce market globally, and to decipher the effect of existing trade regulations, among other variables, on e-trading patterns and to inform policy. We used a comprehensive list of 811 non-native plant species in China present in 1 of the 3 phases of the invasion continuum (i.e., introduced, naturalized, and invasive). The price, propagule types, and quantities of the species offered for sale were retrieved from 9 online stores, including 2 of the largest platforms. Over 30% of the non-native species were offered for sale in the online marketplaces; invasive non-native species dominated the list (45.53%). No significant price difference was observed across the non-native species of the 3 invasion categories. Among the 5 propagule types, a significantly higher number of non-native species were offered for sale as seeds. The regression models and path analyses consistently revealed a direct positive effect of the number of uses and species' minimum residence time and an indirect effect of biogeography on the pattern of trade in non-native plant species when minimal phylogenetic signal was detected. A review of the existing phytosanitary regulations in China revealed their inadequacy in managing e-trading of non-native plant species. To address the problem, we propose integration of a standardized risk assessment framework that considers perceptions of stakeholders and is adaptable based on continuous surveillance of the trade network. If implemented successfully, the measures could provide a template for other countries to strengthen trading regulations for non-native plant species and take proactive management measures.


La venta de plantas no nativas en el mercado virtual más grande y sus implicaciones para la invasión biológica Resumen El mercado virtual en internet se reconoce cada vez más como una vía de dispersión de especies vegetales no nativas difícil de controlar. Intentamos identificar la flora no nativa presente en el mercado virtual chino, el mayor mercado de comercio electrónico del mundo, para descifrar el efecto de las regulaciones comerciales vigentes, entre otras variables, en los patrones de comercio electrónico e informar a las políticas. Utilizamos una lista integral de 811 especies de plantas no nativas de China presentes en una de las tres fases de invasión (es decir, introducidas, naturalizadas o invasoras). El precio, los tipos de propágulos y las cantidades de las especies puestas a la venta se recuperaron de nueve tiendas en línea, incluidas dos de las mayores plataformas. Más del 30% de las especies no nativas se pusieron a la venta en los mercados en línea; las especies no nativas invasoras dominaron esta lista (45,53%). No se observaron diferencias significativas de precio entre las especies no nativas en las tres categorías de invasión. Entre los cinco tipos de propágulos, se puso a la venta un número significativamente mayor de especies no nativas en forma de semillas. Los modelos de regresión y los análisis de trayectoria revelaron un efecto positivo directo y constante del número de usos y del tiempo mínimo de residencia de las especies y un efecto indirecto de la biogeografía sobre el patrón de comercio de especies vegetales no nativas cuando se detectó una señal filogenética mínima. Una revisión de la normativa fitosanitaria vigente en China reveló su insuficiencia para gestionar el comercio electrónico de las especies vegetales no nativas. Para abordar el problema, proponemos la integración de un marco normalizado de evaluación de riesgos que tenga en cuenta las percepciones de los actores y sea adaptable en función de la vigilancia continua de la red comercial. Si se aplican con éxito, las medidas podrían servir de modelo para que otros países refuercen la normativa sobre comercio de especies vegetales no nativas y adopten medidas proactivas de gestión.


Asunto(s)
Conservación de los Recursos Naturales , Plantas , Filogenia , Especies Introducidas , Comercio
13.
J Environ Manage ; 332: 117358, 2023 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-36724595

RESUMEN

While altitude affects climatic characteristics, terrestrial plant habitats, and species composition, few studies considered the effects of altitude on ecosystem multifunctionality (EMF). Here, we teased apart the EMF at different altitude with a linear piecewise quantile regression and explore ecosystem functions and environmental factors with EMF along the altitudinal gradient across the Tibetan Plateau. Then, we estimated the response of ecosystem functions to environmental factors, and explain the impact of environmental factors on EMF through the structural equation model. Our data revealed an EMF changepoint at an altitude of about 3900 m where the EMF could be segregated into low- and high-altitude patterns. Our results indicate that water availability drives the EMF mainly through improving soil nutrients and microbe cycling functions in low-altitude regions; conversely, water-heat and phenological conditions regulate the EMF through the role of plant productivity and soil nutrients in high-altitude regions. As such, our EMF analysis suggests that to maintain the long-term stability of the grassland ecosystem, it becomes critical to fully consider the differences in the altitudinal patterns and mechanisms, particularly under the ongoing climate change.


Asunto(s)
Ecosistema , Pradera , Tibet , Altitud , Plantas , Suelo/química , Agua
14.
Acta Neuropsychiatr ; 35(2): 118-122, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35634747

RESUMEN

OBJECTIVE: Alzheimer's disease (AD) has prolonged asymptomatic or mild symptomatic periods. Given that there is an increase in treatment options and that early intervention could modify the disease course, it is desirable to devise biological indices that may differentiate AD and nonAD at mild cognitive impairment (MCI) stage. METHODS: Based on two well-acknowledged observations of background slowing (attenuation in alpha power and enhancement in theta and delta powers) and early involvement of posterior cingulate cortex (PCC, a neural hub of default-mode network), this study devised novel neural markers, namely, spectral ratios of alpha1 to delta and alpha1 to theta in the PCC. RESULTS: We analysed 46 MCI patients, with 22 ADMCI and 24 nonADMCI who were matched in age, education, and global cognitive capability. Concordant with the prediction, the regional spectral ratios were lower in the ADMCI group, suggesting its clinical application potential. CONCLUSION: Previous research has verified that neural markers derived from clinical electroencephalography may be informative in differentiating AD from other neurological conditions. We believe that the spectral ratios in the neural hubs that show early pathological changes can enrich the instrumental assessment of brain dysfunctions at the MCI (or pre-clinical) stage.


Asunto(s)
Enfermedad de Alzheimer , Disfunción Cognitiva , Humanos , Enfermedad de Alzheimer/patología , Disfunción Cognitiva/diagnóstico , Electroencefalografía , Giro del Cíngulo , Escolaridad
15.
Clin Endocrinol (Oxf) ; 97(1): 64-71, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35394663

RESUMEN

OBJECTIVE: The objective of this study is to assess the relationship between hypothalamic-pituitary-adrenal (HPA) axis activity, vascular function and insulin sensitivity in healthy adults. DESIGN: Open observational study. PATIENTS: Thirty healthy adults were studied at the Endocrine Research Unit, Repatriation General Hospital, Adelaide, SA, Australia. MEASUREMENTS: HPA activity was assessed from the serum cortisol 30 min after 1 µg ACTH1-24 (Novartis Pharmaceuticals). Subjects with a cortisol below (n = 15) and above (n = 15) the median were categorized as low and high responders, respectively. Reactive hyperaemia index (RHI) was measured fasting to estimate endothelial function. Matsuda index was calculated from glucose and insulin concentrations collected fasting and 30 minutely for 2 h after a mixed meal (10 kcal/kg, 45% carbohydrate, 15% protein, 40% fat). The primary endpoint was the difference in RHI between low and high responders. RESULTS: There were no significant differences in age (61 ± 9 vs. 64 ± 7 years, p = .19), body mass index (BMI; 26 ± 3 vs. 24 ± 4 kg/m2 , p = .25) and sex (p = .71) between low and high responders. High responders had a lower RHI (2.1 ± 0.2 vs. 2.6 ± 0.2, p = .04) than low responders and there was a negative association between RHI and peak cortisol post ACTH1-24 (ß = -.56, p < .01). There were no significant differences in Matsuda index (15.0 ± 2.4 vs. 22.7 ± 5.2, p = .19) between high and low responders. CONCLUSION: In healthy adults, endothelial dysfunction is likely to contribute to the association between HPA hyperactivity and increased cardiovascular risk. As insulin sensitivity was not different in high and low responders, endothelial dysfunction is not primarily secondary to insulin resistance.


Asunto(s)
Sistema Hipotálamo-Hipofisario , Sistema Hipófiso-Suprarrenal , Hormona Adrenocorticotrópica/metabolismo , Adulto , Humanos , Hidrocortisona , Sistema Hipotálamo-Hipofisario/metabolismo , Insulina , Sistema Hipófiso-Suprarrenal/metabolismo
16.
Phys Rev Lett ; 128(20): 206801, 2022 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-35657902

RESUMEN

X-ray standing-wave (XSW) excited photoelectron emission was used to measure the site-specific valence band (VB) for ½ monolayer (ML) Pt grown on a SrTiO_{3} (001) surface. The XSW induced modulations in the core level (CL), and VB photoemission from the surface and substrate atoms were monitored for three hkl substrate Bragg reflections. The XSW CL analysis shows the Pt to have a face-centered-cubic-like cube-on-cube epitaxy with the substrate. The XSW VB information compares well to a density functional theory calculated projected density of states from the surface and substrate atoms. Overall, this Letter represents a novel method for determining the contribution to the density of states by valence electrons from specific atomic surface sites.

17.
Nitric Oxide ; 122-123: 47-53, 2022 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-35367633

RESUMEN

BACKGROUND: Arginine metabolites are associated with cardiovascular and all-cause mortality in several patient groups. We investigated whether arginine metabolites are associated with mortality in patients with critical illness and whether associations are independent of other factors affecting prognosis in an Intensive Care Unit (ICU). METHODS: 1155 acutely unwell adult patients admitted to a mixed medical-surgical ICU were studied. Arginine, asymmetric dimethyl-l-arginine (ADMA), monomethyl-l-arginine (MMA), symmetric dimethyl-l-arginine (SDMA) and l-homoarginine were measured in a plasma sample collected at admission to ICU by liquid chromatography tandem mass spectrometry. Risk of death score was calculated using data submitted to the Australia and New Zealand Intensive Care Society. RESULTS: In this cohort, 163 patients (14.1%) died. ADMA (odds ratio = 1.159 (1.033-1.300) per 0.1 µmol/L increment, p = 0.012), homoarginine (odds ratio = 0.963 (0.934-0.992), p = 0.013) and risk of death score (odds ratio = 1.045 (1.037-1.053) per 1% increment, p < 0.001) were independently associated with mortality in ICU patients. The area under the receiver operator characteristic curve for risk of death score, ADMA and homoarginine combined for mortality was greater than for risk of death score alone (0.815 (95% CI 0.790-0.837) vs 0.796 (95% CI 0.781-0.820), p = 0.019). Other arginine metabolites were not independently associated with mortality. CONCLUSIONS: ADMA is positively and homoarginine negatively associated with mortality in ICU patients, independent of other clinical factors. Measuring ADMA and homoarginine may refine models to predict ICU mortality. Reducing ADMA and increasing homoarginine are potential therapeutic targets to reduce mortality in critically ill patients.


Asunto(s)
Sistema Cardiovascular , Homoarginina , Adulto , Arginina/metabolismo , Biomarcadores/metabolismo , Sistema Cardiovascular/metabolismo , Estudios de Cohortes , Enfermedad Crítica , Homoarginina/metabolismo , Humanos
18.
Faraday Discuss ; 236(0): 178-190, 2022 Aug 25.
Artículo en Inglés | MEDLINE | ID: mdl-35514290

RESUMEN

A combined high resolution X-ray photoelectron spectroscopy and X-ray standing wave study into the adsorption structure of hydrogenated graphene on Ir(111) is presented. By exploiting the unique absorption profiles and significant modulations in signal intensity found within the X-ray standing wave results, we refine the fitting of the C 1s X-ray photoelectron spectra, allowing us to disentangle the contributions from hydrogenation of graphene in different high-symmetry regions of the moiré supercell. We clearly demonstrate that hydrogenation in the FCC regions results in the formation of a graphane-like structure, giving a standalone component that is separated from the component assigned to the similar structure in the HCP regions. The contribution from dimer structures in the ATOP regions is found to be minor or negligible. This is in contrast to the previous findings where a dimer structure was assumed to contribute significantly to the sp3 part of the C 1s spectra. The corrugation of the remaining pristine parts of the H-graphene is shown to increase with the H coverage, reflecting an increasing number and size of pinning centers of the graphene to the Ir(111) substrate with increasing H exposure.

19.
Faraday Discuss ; 236(0): 267-287, 2022 Aug 25.
Artículo en Inglés | MEDLINE | ID: mdl-35543094

RESUMEN

The key charge transfer processes in electrochemical energy storage devices occur at electrode-electrolyte interfaces, which are typically buried, making it challenging to access their interfacial chemistry. In the case of Li-ion batteries, metallic Li electrodes hold promise for increasing energy and power densities and, when used in conjunction with solid electrolytes, the adverse safety implications associated with dendrite formation in organic liquid electrolytes can potentially be overcome. To better understand the stability of solid electrolytes when in contact with alkali metals and the reactions that occur, here we consider the deposition of thin (∼10 nm) alkali metal films onto solid electrolyte surfaces, where the metal is thin enough that X-ray photoelectron spectroscopy can probe the buried electrode-electrolyte interface. We highlight the importance of in situ alkali metal deposition by assessing the contaminant species that are present after glovebox handling and the use of 'inert' transfer devices. Consequently, we compare and contrast three available methods for in situ alkali-metal deposition; Li sputter deposition, Li evaporation, and Li plating induced by e- flood-gun irradiation. Studies on both a sulphide solid electrolyte (Li6PS5Cl), and a single-layer graphene probe surface reveal that the more energetic Li deposition methods, such as sputtering, can induce surface damage and interfacial mixing that are not seen with thermal evaporation. This indicates that the appropriate selection of the Li deposition method for in situ studies is required to observe representative behaviour, and the results of previous studies involving energetic deposition may warrant further evaluation.

20.
Faraday Discuss ; 239(0): 250-262, 2022 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-35848780

RESUMEN

Germanium selenide (GeSe) bulk crystals, thin films and solar cells are investigated with a focus on acceptor-doping with silver (Ag) and the use of an Sb2Se3 interfacial layer. The Ag-doping of GeSe occurred by a stoichiometric melt growth technique that created Ag-doped GeSe bulk crystals. A combination of capacitance voltage measurements, synchrotron radiation photoemission spectroscopy and surface space-charge calculations indicates that Ag-doping increases the hole density from 5.2 × 1015 cm-3 to 1.9 × 1016 cm-3. The melt-grown material is used as the source for thermally evaporated GeSe films within solar cells. The cell structure with the highest efficiency of 0.260% is FTO/CdS/Sb2Se3/undoped-GeSe/Au, compared with solar cells without the Sb2Se3 interfacial layer or with the Ag-doped GeSe.

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