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1.
J Am Chem Soc ; 146(1): 460-467, 2024 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-38109256

RESUMO

Dielectric ceramic capacitors with high recoverable energy density (Wrec) and efficiency (η) are of great significance in advanced electronic devices. However, it remains a challenge to achieve high Wrec and η parameters simultaneously. Herein, based on density functional theory calculations and local structure analysis, the feasibility of developing the aforementioned capacitors is demonstrated by considering Bi0.25Na0.25Ba0.5TiO3 (BNT-50BT) as a matrix material with large local polarization and structural distortion. Remarkable Wrec and η of 16.21 J/cm3 and 90.5% have been achieved in Bi0.25Na0.25Ba0.5Ti0.92Hf0.08O3 via simple chemical modification, which is the highest Wrec value among reported bulk ceramics with η greater than 90%. The examination results of local structures at lattice and atomic scales indicate that the disorderly polarization distribution and small nanoregion (∼3 nm) lead to low hysteresis and high efficiency. In turn, the drastic increase in local polarization activated via the ultrahigh electric field (80 kV/mm) leads to large polarization and superior energy storage density. Therefore, this study emphasizes that chemical design should be established on a clear understanding of the performance-related local structure to enable a targeted regulation of high-performance systems.

2.
Small ; 20(7): e2306486, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37803415

RESUMO

Lead-free antiferroelectrics with excellent energy storage performance can become the core components of the next-generation advanced pulse power capacitors. However, the low energy storage efficiency caused by the hysteresis of antiferroelectric-ferroelectric transition largely limits their development toward miniaturization, lightweight, and integration. In this work, an ultrahigh recoverable energy storage density of ≈11.4 J cm-3 with a high efficiency of ≈80% can be realized in La-modified Ag0.5 Na0.5 NbO3 antiferroelectric ceramics at an ultrahigh breakdown electric field of ≈67 kV mm-1 by the compromise optimization between antiferroelectricity enhancement and nanodomain engineering, resulting in the transformation of large-size ferrielectric antipolar stripe domains into ultrasmall antiferroelectric nanodomains or polarization nanoregions revealing as Moiré fringe structures. In addition, the enhanced transparency with increasing La content can also be clearly observed. This work not only develops new lead-free antiferroelectric energy storage materials with high application potential but also demonstrates that the strategy of compromise optimization between antiferroelectricity modulation and nanodomain engineering is an effective avenue to enhance the energy storage performance of antiferroelectrics.

3.
Microb Ecol ; 87(1): 28, 2024 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-38182675

RESUMO

High mountain freshwater systems are particularly sensitive to the impacts of global warming and relevant environmental changes. Microorganisms contribute substantially to biogeochemical processes, yet their distribution patterns and driving mechanism in alpine streams remain understudied. Here, we examined the bacterial and fungal community compositions in stream biofilm along the elevational gradient of 745-1874 m on Mt. Kilimanjaro and explored their alpha and beta diversity patterns and the underlying environmental drivers. We found that the species richness and evenness monotonically increased towards higher elevations for bacteria, while were non-significant for fungi. However, both bacterial and fungal communities showed consistent elevational distance-decay relationships, i.e., the dissimilarity of assemblage composition increased with greater elevational differences. Bacterial alpha diversity patterns were mainly affected by chemical variables such as total nitrogen and phosphorus, while fungi were affected by physical variables such as riparian shading and stream width. Notably, climatic variables such as mean annual temperature strongly affected the elevational succession of bacterial and fungal community compositions. Our study is the first exploration of microbial biodiversity and their underlying driving mechanisms for stream ecosystems in tropical alpine regions. Our findings provide insights on the response patterns of tropical aquatic microbial community composition and diversity under climate change.


Assuntos
Microbiota , Rios , Tanzânia , Bactérias/genética , Biofilmes
4.
Environ Res ; 247: 118165, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38215923

RESUMO

BACKGROUND: Airborne particulate matter pollution has been linked to occurrence of childhood allergic rhinitis (AR). However, the relationships between exposure to particulate matter with an aerodynamic diameter ≤1 µm (PM1) during early life (in utero and first year of life) and the onset of childhood AR remain largely unknown. This study aims to investigate potential associations of in utero and first-year exposures to size-segregated PMs, including PM1, PM1-2.5, PM2.5, PM2.5-10, and PM10, with childhood AR. METHODS: We investigated 29286 preschool children aged 3-6 years in 7 Chinese major cities during 2019-2020 as the Phase II of the China Children, Families, Health Study. Machine learning-based space-time models were utilized to estimate early-life residential exposure to PM1, PM2.5, and PM10 at 1 × 1-km resolutions. The concentrations of PM1-2.5 and PM2.5-10 were calculated by subtracting PM1 from PM2.5 and PM2.5 from PM10, respectively. Multiple mixed-effects logistic models were used to assess the odds ratios (ORs) and 95% confidence intervals (CIs) of childhood AR associated with per 10-µg/m3 increase in exposure to particulate air pollution during in utero period and the first year of life. RESULTS: Among the 29286 children surveyed (mean ± standard deviation, 4.9 ± 0.9 years), 3652 (12.5%) were reported to be diagnosed with AR. Average PM1 concentrations during in utero period and the first year since birth were 36.3 ± 8.6 µg/m3 and 33.1 ± 6.9 µg/m3, respectively. Exposure to PM1 and PM2.5 during pregnancy and the first year of life was associated with an increased risk of AR in children, and the OR estimates were higher for each 10-µg/m3 increase in PM1 than for PM2.5 (e.g., 1.132 [95% CI: 1.022-1.254] vs. 1.079 [95% CI: 1.014-1.149] in pregnancy; 1.151 [95% CI: 1.014-1.306] vs. 1.095 [95% CI: 1.008-1.189] in the first year of life). No associations were observed between AR and both pre- and post-natal exposure to PM1-2.5, indicating that PM1 rather than PM1-2.5 contributed to the association between PM2.5 and childhood AR. In trimester-stratified analysis, childhood AR was only found to be associated with exposure to PM1 (OR = 1.077, 95% CI: 1.027-1.128), PM2.5 (OR = 1.048, 95% CI: 1.018-1.078), and PM10 (OR = 1.032, 95% CI: 1.007-1.058) during the third trimester of pregnancy. Subgroup analysis suggested stronger PM-AR associations among younger (<5 years old) and winter-born children. CONCLUSIONS: Prenatal and postnatal exposures to ambient PM1 and PM2.5 were associated with an increased risk of childhood AR, and PM2.5-related hazards could be predominantly attributed to PM1. These findings highlighted public health significance of formulating air quality guideline for ambient PM1 in mitigating children's AR burden caused by particulate air pollution.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Rinite Alérgica , Pré-Escolar , Gravidez , Feminino , Humanos , Material Particulado/análise , Poluentes Atmosféricos/toxicidade , Estudos Transversais , Exposição Ambiental/análise , Poluição do Ar/efeitos adversos , Poluição do Ar/análise , Rinite Alérgica/etiologia , Rinite Alérgica/induzido quimicamente , China/epidemiologia , Poeira/análise
5.
Small ; 19(47): e2303768, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37485639

RESUMO

Lead-free dielectric ceramics with excellent energy-storage performance are crucial to the development of the next-generation advanced pulse power capacitors. However, low energy-storage density limits the evolution of capacitors toward lightweight, miniaturization, and integration. Here, an effective strategy of constructing highly dynamic polarization heterogeneous nanoregions is proposed in lead-free relaxors to realize an ultrahigh energy-storage density of ≈8.0 J cm-3 , making almost ten times the growth of energy-storage density compared with pure Bi0.5 Na0.5 TiO3 ceramic, accompanied by a higher energy efficiency of ≈80% as well as an ultrafast discharge rate of ≈20 ns. Ultrasmall polarization heterogeneous nanoregions with different orientations and ultrahigh flexibility, and significantly decreased grain size to submicron lead to reduced heat loss, improved breakdown electric field and polarization, enhanced relaxation, and delayed polarization saturation behaviors, contributing to the remarkable energy-storage performance. Moreover, the breakdown path distribution or electrical tree evolution behaviors are systematically studied to reveal the origin of ultrahigh breakdown electric field through phase field simulations. This work demonstrates that constructing highly dynamic polarization heterogeneous nanoregions is a powerful approach to develop new lead-free dielectric materials with high energy-storage performance.

6.
Mar Drugs ; 21(2)2023 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-36827125

RESUMO

Parasitic diseases still threaten human health. At present, a number of parasites have developed drug resistance, and it is urgent to find new and effective antiparasitic drugs. As a rich source of biological compounds, marine natural products have been increasingly screened as candidates for developing new antiparasitic drugs. The literature related to the study of the antigenic animal activity of marine natural compounds from invertebrates and microorganisms was selected to summarize the research progress of marine compounds and the structure-activity relationship of these compounds in the past five years and to explore the possible sources of potential antiparasitic drugs for parasite treatment.


Assuntos
Anti-Infecciosos , Produtos Biológicos , Animais , Humanos , Antiparasitários , Invertebrados , Organismos Aquáticos
7.
Ecotoxicol Environ Saf ; 264: 115451, 2023 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-37703807

RESUMO

BACKGROUND: Studies suggested that greenness could reduce death risks related to ambient exposure to particulate matter (PM), while the available evidence was mixed across the globe and substantially exiguous in low- and middle-income countries. By conceiving an individual-level case-crossover study in central China, this analysis primarily aimed to quantify PM-mortality associations and examined the modification effect of greenness on the relationship. METHODS: We investigated a total of 177,058 nonaccidental death cases from 12 counties in central China, 2008-2012. Daily residential exposures to PM2.5 (aerodynamic diameter <2.5 µm), PMc (aerodynamic diameter between 2.5 and 10 µm), and PM10 (aerodynamic diameter <10 µm) were assessed at a 1 × 1-km resolution through satellite-derived machine-learning models. Residential surrounding greenness was assessed using satellite-derived enhanced vegetation index (EVI) and normalized difference vegetation index (NDVI) at multiple buffer sizes (250, 500, and 1000 m). To quantify the acute mortality risks associated with short-term exposure to PM2.5, PMc, and PM10, a time-stratified case-crossover design was utilized in conjunction with a conditional logistic regression model in our main analyses. To investigate the effect modification of greenness on PM-mortality associations, we grouped death cases into low, medium, and high greenness levels using cutoffs of 25th and 75th percentiles of NDVI or EVI exposure, and examined potential effect heterogeneity in PM-related mortality risks among these groups. RESULTS: Mean concentrations (standard deviation) on the day of death were 73.8 (33.4) µg/m3 for PM2.5, 43.9 (17.3) µg/m3 for PMc, and 117.5 (44.9) µg/m3 for PM10. Size-fractional PM exposures were consistently exhibited significant associations with elevated risks of nonaccidental and circulatory mortality. For every increase of 10-µg/m3 in PM exposure, percent excess risks of nonaccidental and circulatory mortality were 0.271 (95% confidence interval [CI]: 0.010, 0.533) and 0.487 (95% CI: 0.125, 0.851) for PM2.5 at lag-01 day, 0.731 (95% CI: 0.108, 1.359) and 1.140 (95% CI: 0.267, 2.019) for PMc at lag-02 day, and 0.271 (95% CI: 0.010, 0.533) and 0.386 (95% CI: 0.111, 0.662) for PM10 at lag-01 day, respectively. Compared to participants in the low-level greenness areas, those being exposed to higher greenness were found to be at lower PM-associated risks of nonaccidental and circulatory mortality. Consistent evidence for alleviated risks in medium or high greenness group was observed in subpopulations of female and younger groups (age <75). CONCLUSIONS: Short-term exposure to particulate air pollution was associated with elevated risks of nonaccidental and circulatory death, and individuals residing in higher neighborhood greenness possessed lower risk of PM-related mortality. These findings emphasized the potential public health advantages through incorporating green spaces into urban design and planning.


Assuntos
Poluição do Ar , Poeira , Feminino , Humanos , Estudos Cross-Over , Material Particulado/toxicidade , Poluição do Ar/efeitos adversos , China
8.
Environ Microbiol ; 24(12): 5734-5748, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36156840

RESUMO

Seasonal variation has been shown to influence symbiotic bacterial community composition and structure in amphibians. It is still unknown how the symbiotic bacterial community assembly changes during different seasons, especially for amphibians who are particularly sensitive to environmental change. We found significant differences in the composition and diversity (alpha and beta diversity) of amphibian skin and gut bacteria. Co-occurrences network analysis showed that seasonal variation reduced the microbial network complexity of amphibians from summer to autumn. The normalized stochastic ratio (NST) and phylogenetic bin-based null model analysis (iCAMP) models showed that the same result that stochastic processes was the major factor regulating the symbiotic bacterial community assembly mechanisms of amphibians. From summer to autumn, the symbiotic bacterial community assembly mechanisms declined in the contribution of stochastic processes, while increasing in the contribution of deterministic processes. Dispersal limitation was the dominant microbial assembly mechanism, followed by homogeneous selection, and then heterogeneous selection in the symbiotic bacterial community communities of amphibians between summer and autumn. Furthermore, higher niche width of the symbiotic bacterial community of amphibians was found in summer than autumn. Overall, these results demonstrated that seasonal variation influenced amphibian symbiotic bacterial community between summer and autumn.


Assuntos
Anfíbios , Bactérias , Animais , Estações do Ano , Filogenia , Bactérias/genética , Processos Estocásticos
9.
Microb Ecol ; 84(2): 565-579, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34545413

RESUMO

Nitrogen (N) and phosphorus (P) have significant effects on soil microbial community diversity, composition, and function. Also, trees of different life stages have different fertilization requirements. In this study, we designed three N additions and three P levels (5 years of experimental treatment) at two Metasequoia glyptostroboides plantations of different ages (young, 6 years old; middle mature, 24 years old) to understand how different addition levels of N and P affect the soil microbiome. Here, the N fertilization of M. glyptostroboides plantation land (5 years of experimental treatment) significantly enriched microbes (e.g., Lysobacter, Luteimonas, and Rhodanobacter) involved in nitrification, denitrification, and P-starvation response regulation, which might further lead to the decreasing in alpha diversity (especially in 6YMP soil). The P addition could impact the genes involved in inorganic P-solubilization and organic P-mineralization by increasing soil AP and TP. Moreover, the functional differences in the soil microbiomes were identified between the 6YMP and 24YMP soil. This study provides valuable information that improves our understanding on the effects of N and P input on the belowground soil microbial community and functional characteristics in plantations of different stand ages.


Assuntos
Microbiota , Fósforo , China , Nitrogênio/análise , Fósforo/análise , Solo , Microbiologia do Solo
10.
Arch Psychiatr Nurs ; 36: 28-33, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35094822

RESUMO

OBJECTIVE: To assess the prevalence of depressive symptoms and subjective occupational well-being, and examine the mediating role of resilience between depressive symptoms and subjective occupational well-being among nursing home staff as well. MATERIALS AND METHODS: The cross-sectional study involving 236 convenient nursing home staff with an average age of 25.73 years was conducted from November 2020 till January 2021 in Jinan and Heze city, Shandong Province. Participants filled out the questionnaires of demographic information, depressive symptoms, resilience and subjective occupational well-being. Descriptive analysis, Pearson correlations and mediation analysis based on PROCESS macro were conducted. RESULTS: The study revealed that the prevalence of depressive symptoms among nursing home staff was 30.1%. Depressive symptoms were negatively related to subjective occupational well-being (r = -0.336, P < 0.001) and resilience (r = -0.373, P < 0.001), and resilience was positively correlated with subjective occupational well-being (r = 0.390, P < 0.001). Moreover, resilience mediated the relationship between depressive symptoms and subjective occupational well-being with the mediating effect accounting for 35.47% of the total effect. CONCLUSION: Depressive symptoms were highly prevalent among nursing home staff. Resilience could mediate the association between depressive symptoms and subjective occupational well-being. It is advisable to pay more attention to mental health among nursing home staff and contribute to the development of effective resilience improvement interventions to enhance subjective occupational well-being.


Assuntos
Depressão , Casas de Saúde , Adulto , Estudos Transversais , Depressão/epidemiologia , Depressão/psicologia , Humanos , Prevalência , Inquéritos e Questionários
11.
Psychogeriatrics ; 22(2): 236-242, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35048481

RESUMO

BACKGROUND: The COVID-19 pandemic has influenced all social spaces and older adults are susceptible to COVID-19. Geriatric caregivers in nursing homes might experience death anxiety when faced with infected older adults and a closed working environment. Death anxiety is a negative and formidable affective state. Yet, little is currently known about the relationships among death anxiety, self-esteem, and health-related quality of life among geriatric caregivers during the COVID-19 pandemic. This study aimed to examine whether self-esteem could moderate the association between death anxiety and health-related quality of life during the pandemic. METHODS: A cross-sectional study was conducted in Jinan and Heze cities, Shandong Province, from November 2020 to January 2021. Participants comprised a convenience sample of 236 geriatric caregivers in nursing homes. Data on sociodemographic variables, death anxiety, self-esteem, and health-related quality of life were collected. Descriptive analysis, Pearson correlation, and moderated analysis were used for statistical analysis. RESULTS: Self-esteem moderated the association between death anxiety and health-related quality of life (death anxiety × self-esteem: B = -0.113, 95% CI: -0.143, -0.018). CONCLUSION: This study revealed that self-esteem played a moderating role between death anxiety and health-related quality of life during the pandemic, which implies that mental health should be given more attention, and that interventions for improving self-esteem need to be carried out.


Assuntos
COVID-19 , Qualidade de Vida , Idoso , Ansiedade/epidemiologia , Ansiedade/psicologia , COVID-19/epidemiologia , Cuidadores , Estudos Transversais , Depressão , Humanos , Pandemias , SARS-CoV-2
12.
Zhongguo Dang Dai Er Ke Za Zhi ; 24(3): 249-254, 2022 Mar 15.
Artigo em Inglês, Zh | MEDLINE | ID: mdl-35351253

RESUMO

OBJECTIVES: To investigate the efficacy and application value of plasma exchange as an adjuvant therapy in children with hemophagocytic syndrome (HPS). METHODS: A prospective randomized controlled trial was designed. Forty children with severe HPS were enrolled, who were treated in the pediatric intensive care unit (PICU) of Hunan Children's Hospital from October 2018 to October 2020. The children were randomly divided into a plasma exchange group and a conventional treatment group using a random number table, with 20 children in each group. The children in the conventional treatment group received etiological treatment and conventional symptomatic supportive treatment, and those in the plasma exchange group received plasma exchange in addition to the treatment in the conventional treatment group. The two groups were compared in terms of general information, clinical symptoms and signs before and after treatment, main laboratory markers, treatment outcome, and prognosis. RESULTS: Before treatment, there were no significant differences between the two groups in gender, age, course of the disease before admission, etiological composition, pediatric critical illness score, involvement of organ or system functions, and laboratory markers (P>0.05). After 7 days of treatment, both groups had remission and improvement in clinical symptoms and signs. After treatment, the plasma exchange group had significantly lower levels of C-reactive protein, procalcitonin, and serum protein levels than the conventional treatment group (P<0.05). The plasma exchange group also had significantly lower levels of alanine aminotransferase and total bilirubin than the conventional treatment group (P<0.05). The length of stay in the PICU in the plasma exchange group was significantly shorter than that in the conventional treatment group (P<0.05). The plasma exchange group had a significantly higher treatment response rate than the conventional treatment group (P<0.05). There were no significant differences between the two groups in the total length of hospital stay and 3-month mortality rate (P>0.05). CONCLUSIONS: Plasma exchange as an adjuvant therapy is effective for children with severe HPS. It can improve clinical symptoms and signs and some laboratory markers and shorten the length of stay in the PICU, and therefore, it may become an optional adjuvant therapy for children with severe HPS.


Assuntos
Linfo-Histiocitose Hemofagocítica , Troca Plasmática , Criança , Humanos , Unidades de Terapia Intensiva Pediátrica , Linfo-Histiocitose Hemofagocítica/terapia , Plasmaferese , Estudos Prospectivos
13.
Front Zool ; 18(1): 41, 2021 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-34454525

RESUMO

Many animals lower their metabolic rate in response to low temperatures and scarcity of food in the winter in phenomena called hibernation or overwintering. Living at high altitude on the Tibetan Plateau where winters are very cold, the frog Nanorana parkeri, survives in one of the most hostile environments on Earth but, to date, relatively little is known about the biochemical and physiological adjustments for overwintering by this species. The present study profiled changes in plasma metabolites of N. parkeri between winter and summer using UHPLC-QE-MS non-target metabolomics in order to explore metabolic adaptations that support winter survival. The analysis showed that, in total, 11 metabolites accumulated and 95 were reduced in overwintering frogs compared with summer-active animals. Metabolites that increased included some that may have antioxidant functions (canthaxanthin, galactinol), act as a metabolic inhibitor (mono-ethylhexylphthalate), or accumulate as a product of anaerobic metabolism (lactate). Most other metabolites in plasma showed reduced levels in winter and were generally involved in energy metabolism including 11 amino acids (proline, isoleucine, leucine, valine, phenylalanine, tyrosine, arginine, tryptophan, methionine, threonine and histidine) and 4 carbohydrates (glucose, citrate, succinate, and malate). Pathway analysis indicated that aminoacyl-tRNA biosynthesis, phenylalanine, tyrosine and tryptophan biosynthesis, and nitrogen metabolism were potentially the most prominently altered pathways in overwintering frogs. Changes to these pathways are likely due to fasting and global metabolic depression in overwintering frogs. Concentrations of glucose and urea, commonly used as cryoprotectants by amphibians that winter on land, were significantly reduced during underwater hibernation in N. parkeri. In conclusion, winter survival of the high-altitude frog, N. parkeri was accompanied by substantial changes in metabolomic profiles and this study provides valuable information towards understanding the special adaptive mechanisms of N. parkeri to winter stresses.

14.
Environ Microbiol ; 20(5): 1711-1722, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29528548

RESUMO

Carnivorous members of the Carnivora reside at the apex of food chains and consume meat-only diets, rich in purine, fats and protein. Here, we aimed to identify potential adaptive evolutionary signatures compatible with high purine and fat metabolism based on analysis of host genomes and symbiotic gut microbial metagenomes. We found that the gut microbiomes of carnivorous Carnivora (e.g., Felidae, Canidae) clustered in the same clade, and other clades comprised omnivorous and herbivorous Carnivora (e.g., badgers, bears and pandas). The relative proportions of genes encoding enzymes involved in uric acid degradation were higher in the gut microbiomes of meat-eating carnivorans than plant-eating species. Adaptive amino acid substitutions in two enzymes, carnitine O-palmitoyltransferase 1 (CPT1A) and lipase F (LIPF), which play a role in fat digestion, were identified in Felidae-Candidae species. Carnivorous carnivorans appear to endure diets high in purines and fats via gut microbiomic and genomic adaptations.


Assuntos
Bactérias/classificação , Evolução Biológica , Carnívoros/fisiologia , Gorduras na Dieta/administração & dosagem , Microbioma Gastrointestinal , Purinas/administração & dosagem , Ração Animal/análise , Animais , Bactérias/metabolismo , Carnívoros/genética , Carnívoros/microbiologia , Dieta , Gorduras na Dieta/metabolismo , Genoma , Metagenoma , Purinas/metabolismo
15.
Proc Biol Sci ; 284(1862)2017 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-28904137

RESUMO

Wild giant pandas use different parts of bamboo (shoots, leaves and stems) and different bamboo species at different times of the year. Their usage of bamboo can be classified temporally into a distinct leaf stage, shoot stage and transition stage. An association between this usage pattern and variation in the giant panda gut microbiome remains unknown. Here, we found associations using a gut metagenomic approach and nutritional analyses whereby diversity of the gut microbial community in the leaf and shoot stages was significantly different. Functional metagenomic analysis showed that in the leaf stage, bacteria species over-represented genes involved in raw fibre utilization and cell cycle control. Thus, raw fibre utilization by the gut microbiome was guaranteed during the nutrient-deficient leaf stage by reinforcing gut microbiome robustness. During the protein-abundant shoot stage, the functional capacity of the gut microbiome expanded to include prokaryotic secretion and signal transduction activity, suggesting active interactions between the gut microbiome and host. These results illustrate that seasonal nutrient variation in wild giant pandas substantially influences gut microbiome composition and function. Nutritional interactions between gut microbiomes and hosts appear to be complex and further work is needed.


Assuntos
Dieta/veterinária , Microbioma Gastrointestinal , Estações do Ano , Ursidae/microbiologia , Animais , Alimentos , Metagenômica , Folhas de Planta , Brotos de Planta
16.
J Org Chem ; 82(17): 9066-9074, 2017 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-28776369

RESUMO

A unique approach to biaryls was developed on the basis of propargyl vinyl ethers and dienophiles substrates via a gold(I)-initiated cycloisomerization/Diels-Alder/retro-Diels-Alder cascade reaction. The scope and mechanism of the reaction were investigated on the basis of a series of synthetic substrates, control experiments, and DFT calculations.

17.
Chemphyschem ; 17(1): 112-8, 2016 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-26593743

RESUMO

Moisture is shown to activate the reaction between PbI2 and methylammonium halides. In addition, two activating mechanisms are proposed for the formation of CH3 NH3 PbI3 and CH3 NH3 PbI3-x Clx films from a series of carefully controlled experiments. When these rapidly formed perovskite films are directly fabricated into the devices, poor photovoltaic properties are found, due to heavy surface charge recombination. However, the cell performance can be significantly enhanced to 13.63 % and to over 12 % in the steady state for CH3 NH3 PbI3 and to 15.50 % and over 14 % in the steady state for CH3 NH3 PbI3-x Clx , if the rapidly formed perovskite film is annealed. Thus, it is believed that moisture (below 60 % RH) is not a problem for the fabrication of highly efficient perovskite solar cells.

18.
J Med Syst ; 40(8): 184, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27307267

RESUMO

The interpolation technique of computed tomography angiography (CTA) image provides the ability for 3D reconstruction, as well as reduces the detect cost and the amount of radiation. However, most of the image interpolation algorithms cannot take the automation and accuracy into account. This study provides a new edge matching interpolation algorithm based on wavelet decomposition of CTA. It includes mark, scale and calculation (MSC). Combining the real clinical image data, this study mainly introduces how to search for proportional factor and use the root mean square operator to find a mean value. Furthermore, we re- synthesize the high frequency and low frequency parts of the processed image by wavelet inverse operation, and get the final interpolation image. MSC can make up for the shortage of the conventional Computed Tomography (CT) and Magnetic Resonance Imaging(MRI) examination. The radiation absorption and the time to check through the proposed synthesized image were significantly reduced. In clinical application, it can help doctor to find hidden lesions in time. Simultaneously, the patients get less economic burden as well as less radiation exposure absorbed.


Assuntos
Angiografia por Tomografia Computadorizada/métodos , Processamento de Imagem Assistida por Computador/métodos , Análise de Ondaletas , Algoritmos , Humanos , Doses de Radiação
19.
Mol Biol Evol ; 31(10): 2663-71, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25015646

RESUMO

The captive genetic management of threatened species strives to preserve genetic diversity and avoid inbreeding to ensure populations remain available, healthy, and viable for future reintroduction. Determining and responding to the genetic status of captive populations is therefore paramount to these programs. Here, we genotyped 19 microsatellite loci for 240 captive giant pandas (Ailuropoda melanoleuca) (∼64% of the captive population) from four breeding centers, Wolong (WL), Chengdu (CD), Louguantai (LGT), and Beijing (BJ), and analyzed 655 bp of mitochondrial DNA control region sequence for 220 of these animals. High levels of genetic diversity and low levels of inbreeding were estimated in the breeding centers, indicating that the captive population is genetically healthy and deliberate further genetic input from wild animals is unnecessary. However, the LGT population faces a higher risk of inbreeding, and significant genetic structure was detected among breeding centers, with LGT-CD and WL-BJ clustering separately. Based on these findings, we highlight that: 1) the LGT population should be managed as an independent captive population to resemble the genetic distinctness of their Qinling Mountain origins; 2) exchange between CD and WL should be encouraged because of similar wild founder sources; 3) the selection of captive individuals for reintroduction should consider their geographic origin, genetic background, and genetic contribution to wild populations; and 4) combining our molecular genetic data with existing pedigree data will better guide giant panda breeding and further reduce inbreeding into the future.


Assuntos
Animais de Zoológico/genética , DNA Mitocondrial/análise , Ursidae/genética , Animais , Teorema de Bayes , China , Conservação dos Recursos Naturais , Espécies em Perigo de Extinção , Variação Genética , Haplótipos , Repetições de Microssatélites , Linhagem
20.
Conserv Biol ; 29(6): 1497-507, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26372302

RESUMO

Giant panda (Ailuropoda melanoleuca) conservation is a possible success story in the making. If extinction of this iconic endangered species can be avoided, the species will become a showcase program for the Chinese government and its collaborators. We reviewed the major advancements in ecological science for the giant panda, examining how these advancements have contributed to panda conservation. Pandas' morphological and behavioral adaptations to a diet of bamboo, which bear strong influence on movement ecology, have been well studied, providing knowledge to guide management actions ranging from reserve design to climate change mitigation. Foraging ecology has also provided essential information used in the creation of landscape models of panda habitat. Because habitat loss and fragmentation are major drivers of the panda population decline, efforts have been made to help identify core habitat areas, establish where habitat corridors are needed, and prioritize areas for protection and restoration. Thus, habitat models have provided guidance for the Chinese governments' creation of 67 protected areas. Behavioral research has revealed a complex and efficient communication system and documented the need for protection of habitat that serves as a communication platform for bringing the sexes together for mating. Further research shows that den sites in old-growth forests may be a limiting resource, indicating potential value in providing alternative den sites for rearing offspring. Advancements in molecular ecology have been revolutionary and have been applied to population census, determining population structure and genetic diversity, evaluating connectivity following habitat fragmentation, and understanding dispersal patterns. These advancements form a foundation for increasing the application of adaptive management approaches to move panda conservation forward more rapidly. Although the Chinese government has made great progress in setting aside protected areas, future emphasis will be improved management of pandas and their habitat.


Assuntos
Conservação dos Recursos Naturais , Espécies em Perigo de Extinção , Ursidae/fisiologia , Animais , China
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