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1.
Ecol Lett ; 27(6): e14447, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38844351

RESUMEN

Host specialization plays a critical role in the ecology and evolution of plant-microbe symbiosis. Theory predicts that host specialization is associated with microbial genome streamlining and is influenced by the abundance of host species, both of which can vary across latitudes, leading to a latitudinal gradient in host specificity. Here, we quantified the host specificity and composition of plant-bacteria symbioses on leaves across 329 tree species spanning a latitudinal gradient. Our analysis revealed a predominance of host-specialized leaf bacteria. The degree of host specificity was negatively correlated with bacterial genome size and the local abundance of host plants. Additionally, we found an increased host specificity at lower latitudes, aligning with the high prevalence of small bacterial genomes and rare host species in the tropics. These findings underscore the importance of genome streamlining and host abundance in the evolution of host specificity in plant-associated bacteria along the latitudinal gradient.


Asunto(s)
Tamaño del Genoma , Especificidad del Huésped , Hojas de la Planta , Simbiosis , Hojas de la Planta/microbiología , Bacterias/genética , Bacterias/clasificación , Genoma Bacteriano , Árboles/microbiología
2.
Environ Res ; 252(Pt 2): 118792, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38583662

RESUMEN

Coal mining changes groundwater environment, results in deterioration of water quality and endangering human health in the mining area. However, the comprehensive study of groundwater evolution and its potential impact in mining area is still insufficient. In this study, 95 groundwater samples were collected from 2019 to 2020 in a typical mining area of China. Ion ratio coefficients, isotopic tracing technology, Entropy-weighted water quality index (EWQI) and human health risk assessment model (HHRA) were applicated to investigate the hydrochemical variation reasons, groundwater quality and its potential health risk in the study area. Results showed that the groundwater hydrochemical types changed from HCO3∙SO4-Ca∙Mg type to SO4-Ca∙Mg and SO4∙Cl-Ca∙Mg type. Water-rock interaction, agricultural activities, manure and sewage input, precipitation and evaporation controlled the groundwater hydrochemical composition. Groundwater quality showed a trend of fluctuation with an average EWQI of 59.23, 68.92, 63.75, 58.02 and 64.92, respectively. 91.6% of the water samples was fair and acceptable for drinking. The groundwater health risk of nitrate in the study area ranged from 0.03 to 17.80. Infants had the highest health risk and nitrate concentration was the most sensitive parameter. The results will present a comprehensive research of groundwater evolution and potential impacts through a typical mining area example. Thereby offering valuable insights into the influencing factors identification, hydrochemical processes evolution, protection and utilization of groundwater in global mining areas.


Asunto(s)
Monitoreo del Ambiente , Agua Subterránea , Contaminantes Químicos del Agua , Agua Subterránea/química , Agua Subterránea/análisis , Medición de Riesgo , Humanos , China , Monitoreo del Ambiente/métodos , Contaminantes Químicos del Agua/análisis , Calidad del Agua , Minería , Minas de Carbón , Nitratos/análisis
3.
J Environ Manage ; 351: 119728, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38086122

RESUMEN

The interaction between groundwater and surface water, including their recharge relationship and ratio, is crucial for water cycling, management, and pollution control. However, accurately estimating their spatiotemporal interaction at the watershed scale remains challenging. In this study, we used dual stable isotopes (δ18O, δ2H, d-excess, and lc-excess) and hydrochemistry methods to rethink spatiotemporal interaction at the Yiluo River watershed in central China. We collected 20 groundwater and 40 surface water samples over four periods in two seasons (dry and wet). Our results showed that in the downstream region, groundwater recharged surface water in the dry season while surface water recharged groundwater in the wet season, with average recharge ratios of 89.82% and 90.02%, respectively. In the midstream region, surface water recharged groundwater in both seasons with average ratios of 93.79% and 91.35%. In contrast, in the upstream region, groundwater recharged surface water in both seasons with ratios of 67.35% and 76.89%. Seasonal changes in the recharge relationship between surface water and groundwater in the downstream region also been found. Our findings provide valuable insights for watershed-scale water resource and pollution management.


Asunto(s)
Agua Subterránea , Contaminantes Químicos del Agua , Agua , Monitoreo del Ambiente/métodos , Isótopos , Ríos , China , Contaminantes Químicos del Agua/análisis
4.
Am J Respir Cell Mol Biol ; 68(4): 406-416, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36413750

RESUMEN

Transmembrane serine proteases are a group of enzymes that are implicated in diverse biological processes. Transmembrane serine protease 11E (TMPRSS11E) is expressed in epithelial cells. Previous studies on TMPRSS11E mainly focused on its function in tumor progression. In this study, we investigated the association of TMPRSS11E with the inflammatory response. We found that TMPRSS11E levels were upregulated in the BAL fluid of patients with acute respiratory distress syndrome and LPS-stimulated cultured epithelial cells. In an LPS-induced acute lung injury mouse model and a cercal ligation and puncture-induced sepsis model, increased expression levels of TMPRSS11E were also observed in the lung tissues. Knockdown of TMPRSS11E suppressed the proinflammatory cytokine release and alleviated lung injury. In addition, increased TMPRSS11E expression was detected in lung tissues of poly(I:C)-challenged mice, and overexpression of TMPRSS11E aggregated the lung injury. Unexpectedly, ectopic TMPRSS11E expression in macrophages was observed. Protease-activated receptor-1 was proteolytically activated by TMPRSS11E and enhanced the levels of proinflammatory cytokines. Taken together, our results indicate that TMPRSS11E can be induced during inflammatory response triggered by infection. Therefore, interventions with TMPRSS11E can aid in the treatment of pulmonary inflammation.


Asunto(s)
Lesión Pulmonar Aguda , Lipopolisacáridos , Animales , Ratones , Lesión Pulmonar Aguda/patología , Citocinas/metabolismo , Inflamación/patología , Lipopolisacáridos/farmacología , Pulmón/patología , Poli I-C/farmacología
5.
New Phytol ; 240(4): 1534-1547, 2023 11.
Artículo en Inglés | MEDLINE | ID: mdl-37649282

RESUMEN

Predicting and managing the structure and function of plant microbiomes requires quantitative understanding of community assembly and predictive models of spatial distributions at broad geographic scales. Here, we quantified the relative contribution of abiotic and biotic factors to the assembly of phyllosphere bacterial communities, and developed spatial distribution models for keystone bacterial taxa along a latitudinal gradient, by analyzing 16S rRNA gene sequences from 1453 leaf samples taken from 329 plant species in China. We demonstrated a latitudinal gradient in phyllosphere bacterial diversity and community composition, which was mostly explained by climate and host plant factors. We found that host-related factors were increasingly important in explaining bacterial assembly at higher latitudes while nonhost factors including abiotic environments, spatial proximity and plant neighbors were more important at lower latitudes. We further showed that local plant-bacteria associations were interconnected by hub bacteria taxa to form metacommunity-level networks, and the spatial distribution of these hub taxa was controlled by hosts and spatial factors with varying importance across latitudes. For the first time, we documented a latitude-dependent importance in the driving factors of phyllosphere bacteria assembly and distribution, serving as a baseline for predicting future changes in plant phyllosphere microbiomes under global change and human activities.


Asunto(s)
Bacterias , Microbiota , Humanos , ARN Ribosómico 16S/genética , Bacterias/genética , Plantas/genética , Hojas de la Planta/microbiología
6.
Carcinogenesis ; 43(11): 1092-1102, 2022 12 25.
Artículo en Inglés | MEDLINE | ID: mdl-35951670

RESUMEN

TMPRSS11E was found to be upregulated in human nonsmall cell lung cancer samples (NSCLC) and cell lines, and high expression was associated with poor survival of NSCLC patients. The results of in vitro and in vivo experiments showed that overexpressing TMPRSS11E resulted in A549 cell proliferation and migration promotion, while the TMPRSS11E S372A mutant with the mutated catalytic domain lost the promoting function. In addition, in mouse xenograft models, silencing TMPRSS11E expression inhibited the growth of 95D cell-derived tumors. To explore the mechanism of marked upregulation of TMPRSS11E in NSCLC cells, promoter analysis, EMSA, and ChIP assays were performed. STAT3 was identified as the transcription factor responsible for TMPRSS11E transcription. Moreover, the purified recombinant TMPRSS11E catalytic domain exhibited enzymatic activity for the proteolytic cleavage of PAR2. Recombinant TMPRSS11E catalytic domain incubation further activated the PAR2-EGFR-STAT3 pathway. These findings established a mechanism of TMPRSS11E-PAR2-EGFR-STAT3 positive feedback, and the oncogenic role of TMPRSS11E as a PAR2 modulator in NSCLC was revealed.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Animales , Ratones , Humanos , Carcinoma de Pulmón de Células no Pequeñas/patología , Neoplasias Pulmonares/patología , Serina Proteasas/metabolismo , Línea Celular Tumoral , Proliferación Celular , Serina Endopeptidasas/genética , Serina Endopeptidasas/metabolismo , Receptores ErbB/genética , Regulación Neoplásica de la Expresión Génica , Factor de Transcripción STAT3/metabolismo
7.
PLoS Comput Biol ; 17(4): e1008853, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33914731

RESUMEN

When Darwin visited the Galapagos archipelago, he observed that, in spite of the islands' physical similarity, members of species that had dispersed to them recently were beginning to diverge from each other. He postulated that these divergences must have resulted primarily from interactions with sets of other species that had also diverged across these otherwise similar islands. By extrapolation, if Darwin is correct, such complex interactions must be driving species divergences across all ecosystems. However, many current general ecological theories that predict observed distributions of species in ecosystems do not take the details of between-species interactions into account. Here we quantify, in sixteen forest diversity plots (FDPs) worldwide, highly significant negative density-dependent (NDD) components of both conspecific and heterospecific between-tree interactions that affect the trees' distributions, growth, recruitment, and mortality. These interactions decline smoothly in significance with increasing physical distance between trees. They also tend to decline in significance with increasing phylogenetic distance between the trees, but each FDP exhibits its own unique pattern of exceptions to this overall decline. Unique patterns of between-species interactions in ecosystems, of the general type that Darwin postulated, are likely to have contributed to the exceptions. We test the power of our null-model method by using a deliberately modified data set, and show that the method easily identifies the modifications. We examine how some of the exceptions, at the Wind River (USA) FDP, reveal new details of a known allelopathic effect of one of the Wind River gymnosperm species. Finally, we explore how similar analyses can be used to investigate details of many types of interactions in these complex ecosystems, and can provide clues to the evolution of these interactions.


Asunto(s)
Evolución Biológica , Bosques , Árboles , Análisis por Conglomerados , Fenómenos Ecológicos y Ambientales , Modelos Biológicos , Filogenia
8.
Appl Opt ; 61(29): 8783-8791, 2022 Oct 10.
Artículo en Inglés | MEDLINE | ID: mdl-36256012

RESUMEN

Angular color uniformity and luminous flux are the most important figures of merit for a white-light-emitting diode (WLED), and simultaneous improvement of both figures of merit is desired. The cellulose-nanocrystal (CNC)-based optical diffuser has been applied on the WLED module to enhance angular color uniformity, but it inevitably causes the reduction of luminous flux. Here we demonstrate a deep-learning-based inverse design approach to design CNC-coated WLED modules. The developed forward neural network successfully predicts two figures of merit with high accuracy, and the inverse predicting model can rapidly design the structural parameters of CNC film. Further explorations taking advantage of both forward and inverse neutral networks can effectively construct the coating layer for WLED modules to reach the best performance.

9.
Proc Biol Sci ; 288(1948): 20203045, 2021 04 14.
Artículo en Inglés | MEDLINE | ID: mdl-33849320

RESUMEN

The decline in species richness at higher latitudes is among the most fundamental patterns in ecology. Whether changes in species composition across space (beta-diversity) contribute to this gradient of overall species richness (gamma-diversity) remains hotly debated. Previous studies that failed to resolve the issue suffered from a well-known tendency for small samples in areas with high gamma-diversity to have inflated measures of beta-diversity. Here, we provide a novel analytical test, using beta-diversity metrics that correct the gamma-diversity and sampling biases, to compare beta-diversity and species packing across a latitudinal gradient in tree species richness of 21 large forest plots along a large environmental gradient in East Asia. We demonstrate that after accounting for topography and correcting the gamma-diversity bias, tropical forests still have higher beta-diversity than temperate analogues. This suggests that beta-diversity contributes to the latitudinal species richness gradient as a component of gamma-diversity. Moreover, both niche specialization and niche marginality (a measure of niche spacing along an environmental gradient) also increase towards the equator, after controlling for the effect of topographical heterogeneity. This supports the joint importance of tighter species packing and larger niche space in tropical forests while also demonstrating the importance of local processes in controlling beta-diversity.


Asunto(s)
Biodiversidad , Árboles , Ecología , Asia Oriental
10.
BMC Pulm Med ; 21(1): 423, 2021 Dec 20.
Artículo en Inglés | MEDLINE | ID: mdl-34930196

RESUMEN

BACKGROUND: Endobronchial ultrasound (EBUS) elastography has been used in EBUS-guided transbronchial needle aspiration (EBUS-TBNA) to identify malignant lymph nodes based on tissue stiffness. Rapid onsite cytological evaluation (ROSE) has been widely utilized for onsite evaluation of sample adequacy and for guiding sampling during EBUS-TBNA. The aim of this study was to investigate the diagnostic value of combined EBUS elastography and ROSE in evaluating mediastinal and hilar lymph node status. METHODS: Retrospective chart review was performed from December 2018 to September 2020. Patient demographics, EBUS elastography scores, and ROSE, pathologic, and clinical outcome data were collected. The EBUS elastography scores were classified as follows: Type 1, predominantly nonblue; Type 2, partially blue and partially nonblue; and Type 3, predominantly blue. A receiver operating characteristic curve was used to compare the sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio for evaluation of malignant lymph nodes among the EBUS elastography, ROSE, and EBUS combined with ROSE groups. RESULTS: A total of 245 patients (345 lymph nodes) were included. The sensitivity and specificity of the EBUS elastography group for the diagnosis of malignant lymph nodes were 90.51% and 57.26%, respectively. The sensitivity and specificity in the ROSE group were 96.32% and 79.05%, respectively. The sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of EBUS elastography combined with ROSE were 86.61%, 92.65%, 11.78, and 0.14, respectively, and the area under the curve was 0.942. CONCLUSIONS: Combining EBUS elastography and ROSE significantly increased the diagnostic value of EBUS-TBNA in evaluating mediastinal and hilar lymph node status compared to each method alone.


Asunto(s)
Bronquios/diagnóstico por imagen , Diagnóstico por Imagen de Elasticidad/métodos , Biopsia por Aspiración con Aguja Fina Guiada por Ultrasonido Endoscópico/métodos , Endosonografía/métodos , Enfermedades Pulmonares/diagnóstico por imagen , Enfermedades Pulmonares/patología , Ganglios Linfáticos/diagnóstico por imagen , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Ganglios Linfáticos/patología , Metástasis Linfática , Masculino , Mediastino , Persona de Mediana Edad , Estadificación de Neoplasias , Estudios Retrospectivos , Sensibilidad y Especificidad
11.
Immunol Invest ; 49(1-2): 166-177, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31752548

RESUMEN

Associations between vitamin D receptor (VDR) gene polymorphisms and allergic diseases were already reported by many publications. The aim of this meta-analysis was to clarify associations between VDR gene polymorphisms and allergic diseases by combing the results of all relevant publications. Eligible publications were searched from Pubmed, Embase, WOS and CNKI. We used Review Manager to combine the results of individual studies. Twenty-one studies were included in this study. Combined results proved that VDR rs1544410 BsmI (over-dominant comparison: p = .04, OR = 1.14, 95% CI 1.01-1.29; allele comparison: p = .03, OR = 1.11, 95% CI 1.01-1.22) and rs731236 TaqI (dominant comparison: p = .01, OR = 1.18, 95% CI 1.04-1.33) polymorphisms were both associated with allergic diseases. In subgroup analyses by type of disease, we confirmed positive results for rs1544410 BsmI polymorphism in both asthma and atopic dermatitis, and for rs731236 TaqI polymorphism in atopic dermatitis. Besides, in subgroup by ethnicity of participants, we observed significant associations with allergic diseases for rs7975232 ApaI polymorphism in Caucasians, for rs1544410 BsmI polymorphism in Asians and Caucasians, and for rs731236 TaqI polymorphism in Asians. We also investigated associations between VDR rs2228570 FokI polymorphism and allergic diseases, yet no any positive results were detected for this polymorphism. If we only focused on asthma, then positive findings were detected for rs1544410 BsmI polymorphism in Caucasians, and for rs731236 TaqI polymorphism in Asians. Collectively, this meta-analysis proved that VDR rs7975232 ApaI, rs1544410 BsmI and rs731236 TaqI gene polymorphisms may confer susceptibility to allergic diseases in certain populations.


Asunto(s)
Predisposición Genética a la Enfermedad/genética , Hipersensibilidad/genética , Receptores de Calcitriol/genética , Humanos , Polimorfismo de Nucleótido Simple/genética
12.
Opt Lett ; 44(2): 463-466, 2019 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-30644926

RESUMEN

Solution-processed semiconductors that exhibit tunable light absorption and can be directly integrated into state-of-the-art silicon technologies are attractive for near-infrared (NIR) light detection in applications of medical imaging, night vision cameras, hyperspectral sensing, etc. Colloidal quantum dot (CQD) is regarded as a promising candidate for its solution-processability and superior optoelectronic properties. Here we propose an on-chip CQD photodetector, photodiode-oxide-semiconductor field-effect transistor, for NIR light sensing. This CMOS compatible device architecture utilizes silicon as a channel for carrier transport and PbS CQD as the light absorbing material controlling the channel conductivity. While the light with a wavelength longer than about 1100 nm cannot excite a photocurrent in commercial silicon-based photodetectors due to the absorption cutoff of silicon, the proposed photodetector can have responses owing to the usage of a PbS CQD photodiode. Simulations showed that the photodiode could provide photovoltage to the semiconductor, forming an inversion layer at the oxide-semiconductor interface, and the electron density at the interface is significantly enhanced. As a result, currents could flow through this layer with ease between the source and drain electrodes. For a proof-of-concept demonstration, we experimentally connected a CQD photodiode with a commercial silicon transistor and proved that the current from the transistor could be increased by photovoltage provided by the photodiode under NIR light illumination. The device shows a responsivity of 5.9A/W at the wavelength of 1250 nm.

13.
Oecologia ; 190(3): 629-637, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-31214834

RESUMEN

Species with large intraspecific trait variability (ITV) have larger niche breadth than species with low ITV and thus are expected to be more abundant at the local scale. However, whether the positive ITV-abundance relationship holds in heterogeneous local environments remains uncertain. Using an individual-based trait dataset encompassing three leaf traits (leaf area, specific leaf area, and leaf dry mass content) of 20,248 individuals across 80 species in an environmentally heterogeneous subtropical forest in eastern China, ITV for each trait of each species was estimated by rarefaction. Resource-based niche breadth and marginality (the absolute distance between the mean resource states used by a species and the mean plot-wise resource states) were estimated simultaneously by the K-S method and the outlying mean index, respectively. Species with moderate ITV were often locally abundant, while species with large or small ITV were locally rare. This unimodal relationship between ITV and species abundance persisted when traits were analyzed separately and for all tree size classes. There was also a hump-backed relationship between niche breadth and marginality, and ITV was positively associated with niche breadth. The combined results suggest either a trade-off between the benefit from expanding niche breadth to adapt to multiple habitats and the disadvantage of reducing competitive ability, or a scarcity of favorable resources. Our results do not support the traditional thought that ITV positively correlates with species abundance in heterogeneous local environments. Instead, our study suggests that moderate-rather than large-intraspecific trait variability increases species abundance at local scales.


Asunto(s)
Bosques , Árboles , China , Ecosistema , Fenotipo
14.
Appl Opt ; 58(10): 2505-2511, 2019 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-31045045

RESUMEN

Gridline shadowing is one of the main factors affecting the performance of silicon solar cells. In this demonstration, a straightforward, scalable approach is reported to reduce shadowing losses from metallic contacts on silicon solar cells by employing cellulose nanocrystals (CNC) mixed in a polymer- polydimethylsiloxane. The method is highly compatible with current solar cell module manufacturing. The CNC:polymer (CNP) hybrid diffusers, offering highly efficient broadband light diffusion, are applied atop the metallization areas to deflect the light impinging on metallic gridlines toward uncovered active areas on the solar cell. Simulations showed that the CNP diffuser is an excellent candidate for reducing shadowing losses within a wide range of incident angles, as it can reduce more than 30% of shadowing losses at normal incidence, and nearly 50% of the lost light can be recycled at the incident angle of 60°. Taking advantage of reduced shadowing losses, a new 6-busbar technology based on the CNP diffusers is proposed with lower manufacturing complexity and higher overall efficiency.

15.
Appl Opt ; 58(27): 7649-7654, 2019 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-31674423

RESUMEN

Improvement in angular color uniformity is of significant importance to reach high illumination quality for a white LED. In this demonstration, we show potential applications of cellulose-nanocrystal (CNC)-filled polymer for enhancing color uniformity of white LEDs. The excellent optical diffusion capability provided by CNC and the mechanical flexibility offered by the polymer matrix render it a highly efficient color mixer. The CNC-filled polymer was applied on the outer surface of a conventional white LED module to enhance both color and illumination uniformities. It reduced 71.4% of angular color deviation and improved illumination uniformity by 35.5% while maintaining over 85% of light energy transmission. We also demonstrate that for a specific application purpose, such as downlight illumination, one can simultaneously achieve high color uniformity and downlight illumination with reduced glare by constructing the CNC-filled polymer into a CNC-doped lens. In this case, a 0.03%-CNC-filled lens can reduce angular color deviation by 74.0% and achieve a light energy transmission of 85.5%. The light energy transmission can be further improved by advanced lens designs for energy-saving purposes.

16.
Oecologia ; 186(3): 793-803, 2018 03.
Artículo en Inglés | MEDLINE | ID: mdl-29344733

RESUMEN

The importance of intraspecific trait variability (ITV) to the spatial distribution of individual species is unclear. We hypothesized that intraspecific trait dispersions underlying niche processes deviate more from null model expectations, by reducing their spread (range and variance), kurtosis, and standard deviation of near-neighbor distance, for species with aggregated than those with random distributions. The link between species' spatial distributions and ITV patterns was examined using an individual tree-based trait data set, in which specific leaf area, mean leaf area, leaf dry matter content, and diameter at breast height were measured for 18,773 stems of 45 species in a 4.84 ha mapped subtropical forest plot in China. The nearest-neighbor distance analysis showed that, of 45 species, 14 species were distributed in random and 31 species were distributed in aggregation, while no species was distributed in uniform in the plot. The dispersions of all studied traits in species with an aggregated distribution on average deviated more strongly from the null expectation than those in species with a random distribution and that the extent of deviation was negatively associated with the degree of spatial randomness across species. Our results indicate that niche processes are primarily responsible for the spatial structure of species with aggregated distributions, while stochastic processes drive those with random distributions. Our results highlight the fundamental role of ITV in shaping spatial patterns of co-existing species.


Asunto(s)
Bosques , Hojas de la Planta , China , Fenotipo
17.
Opt Lett ; 41(7): 1506-9, 2016 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-27192273

RESUMEN

Large-area patterning of periodic nanostructures using self-assembled nanospheres is of interest for fabricating low-cost plasmonic substrates, such as two-dimensional (2D) metallic gratings. Surface plasmon polaritons (SPPs) excited on metallic gratings have applications in biosensors, thin-film photovoltaics, photoelectrochemical cells, and photodetectors. Here we fabricated large-area metallic gratings using nanosphere lithography, and the geometry of gratings was controlled by the sphere size and distance between nanospheres. Both forward and backward propagating SPPs were observed using the grating coupling geometry. Furthermore, we reported the first observation of localized surface plasmons (LSPs) on this large-area metallic grating by both simulation and experimental studies. Such an LSP mode was confined in the 2D nanocavities and was not supported by dielectric gratings with the same 2D geometry.

18.
Opt Express ; 22 Suppl 6: A1576-88, 2014 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-25607315

RESUMEN

The application of nanostructured indium-doped tin oxide (ITO) electrodes as diffraction gratings for light absorption enhancement in colloidal quantum dot solar cells is numerically investigated using finite-difference time-domain (FDTD) simulation. Resonant coupling of the incident diffracted light with supported waveguide modes in light absorbing layer at particular wavelengths predicted by grating far-field projection analysis is shown to provide superior near-infrared light trapping for nanostructured devices as compared to the planar structure. Among various technologically feasible nanostructures, the two-dimensional nano-branch array is demonstrated as the most promising polarization-independent structure and proved to be able to maintain its performance despite structural imperfections common in fabrication.


Asunto(s)
Suministros de Energía Eléctrica , Electrodos , Nanopartículas del Metal/química , Puntos Cuánticos , Refractometría/instrumentación , Energía Solar , Absorción de Radiación , Simulación por Computador , Diseño Asistido por Computadora , Transferencia de Energía , Diseño de Equipo , Análisis de Falla de Equipo , Lentes , Luz , Nanopartículas del Metal/efectos de la radiación , Modelos Teóricos , Dispersión de Radiación
19.
Glob Chang Biol ; 20(1): 240-50, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24022892

RESUMEN

There is evidence that climate change induced tree mortalities in boreal and temperate forests and increased forest turnover rates (both mortality and recruitment rates) in Amazon forests. However, no study has examined China's tropical and subtropical evergreen broadleaved forests (TEBF) that cover >26% of China's terrestrial land. The sustainability of this biome is vital to the maintenance of local ecosystem services (e.g., carbon sequestration, biodiversity conservation, climatic regulation), many of which may influence patterns of atmospheric circulation and composition at regional to global scales. Here, we analyze time-series data collected from thirteen permanent plots within China's unmanaged TEBF to study whether and how this biome has changed over recent decades. We find that the numbers of individuals and species for shrub and small tree have increased since 1978, whereas the numbers of individuals and species for tree have decreased over this same time period. The shift in species composition is accompanied by a decrease in the mean diameter at breast height (DBH) for all individuals combined. China's TEBF may thereby be transitioning from cohorts of fewer and larger individuals to ones of more and smaller individuals, which shows a unique change pattern differing from the documented. Regional-scale drying is likely responsible for the biome's reorganization. This biome-wide reconstitution would deeply impact the regimes of carbon sequestration and biodiversity conservation and have implications for the sustainability of economic development in the area.


Asunto(s)
Árboles/crecimiento & desarrollo , Biodiversidad , China , Suelo , Clima Tropical
20.
Chem Commun (Camb) ; 60(9): 1072-1088, 2024 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-38174780

RESUMEN

Colloidal quantum dots (CQDs) are a promising class of materials for next-generation optoelectronic devices, such as displays, LEDs, lasers, photodetectors, and solar cells. CQDs can be obtained at low cost and in large quantities using wet chemistry. CQDs have also been produced using various materials, such as CdSe, InP, perovskites, PbS, PbSe, and InAs. Some of these CQD materials absorb and emit photons in the visible region, making them excellent candidates for displays and LEDs, while others interact with low-energy photons in the near-infrared (NIR) region and are intensively utilized in NIR lasers, NIR photodetectors, and solar cells. In this review, we have focused on NIR CQD materials and reviewed the development of CQD materials for solar cells, NIR lasers, and NIR photodetectors since the first set of reports on CQD materials in these particular applications.

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