Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Ann Palliat Med ; 2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-32233619

RESUMO

BACKGROUND: Re-treatment pulmonary tuberculosis (PTB) has a high risk of being multi-drug- or rifampicin-resistant tuberculosis (MDR/RR-TB). The Xpert MTB/RIF assay possesses high efficacy for the evaluation of rifampicin resistance. The aim of the present study was to assess the benefit of the Xpert MTB/ RIF assay in the screening and treatment of MDR/RR-TB in re-treatment PTB patients. METHODS: Patients with suspected re-treatment PTB were prospectively enrolled and divided into Xpert MTB/RIF and mycobacterial tuberculosis (MTB) culture groups. No Xpert MTB/RIF assay was carried out in the MTB culture group. The diagnostic performance and turn-around time (TAT) of MDR/RRTB detection and the culture results of MDR/RR-TB patients following two-month chemotherapy in two groups were calculated and compared. RESULTS: Using phenotypic DST as a reference standard, the positive predictive value of Xpert MTB/RIF for the detection of RR-TB and MDR-TB among re-treatment PTB patients was 90.72% and 77.32%, respectively. The Xpert MTB/RIF group had a significantly shorter interval for the initiation of anti-MDR/ RR-TB treatment {1 [1-1] vs. 52 [47-57] days, P<0.0001}; and following two-month chemotherapy, the percentage of positive culture MDR/RR-TB patients in the Xpert MTB/RIF group was significantly reduced (24.18% vs. 50%, P=0.0003). CONCLUSIONS: Xpert MTB/RIF can accurately screen MDR/RR-TB among re-treatment PTB patients, reducing both the turn-around time for therapy initiation and the percentage of positive culture MDR/ RR-TB patients following two-month chemotherapy. This is not only beneficial for treatment but also for reducing MDR-TB transmission. We recommend that re-treatment PTB patients receive anti-RR/TB chemotherapy following a positive RFP resistance result in the Xpert MTB/RIF assay.

2.
Sci Total Environ ; 711: 135183, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32000350

RESUMO

China is the largest rice producer and consumer in the world. Accurate estimations of paddy rice planting area and rice grain production is important for feeding the increasing population in China. However, Southern China had substantial losses in paddy rice area over the last three decades in those regions where paddy rice has traditionally been produced. Several studies have shown increased paddy rice area in Northeast China. Here we document the annual dynamics of paddy rice area, gross primary production (GPP), and grain production in Northeast China (Heilongjiang, Jilin and Liaoning provinces) during 2000-2017 using agricultural statistical data, satellite images, and model simulations. Annual maps derived from satellite images show that paddy rice area in Northeast China has increased by 3.68 million ha from 2000 to 2017, which is more than the total combined paddy rice area of North Korea, South Korea, and Japan. Approximately 82% of paddy rice pixels had an increase in annual GPP during 2000-2017. The expansion of paddy rice area slowed down substantially since 2015. Annual GPP from those paddy rice fields cultivated continuously over the 18 years were moderately higher than that from other paddy rice fields, which suggested that improved management practices could increase grain production in the region. There was a strong linear relationship between annual GPP and annual rice grain production in Northeast China by province and year, which illustrates the potential of using satellite-based data-driven model to track and assess grain production of paddy rice in the region. Northeast China is clearly an emerging rice production base and plays an increasing role in crop production and food security in China. However, many challenges for the further expansion and sustainable cultivation of paddy rice in Northeast China remain.


Assuntos
Oryza , Agricultura , China , Grão Comestível , Japão , República da Coreia
3.
Int Immunopharmacol ; 80: 106148, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31978802

RESUMO

INTRODUCTION: The efficacy and safety of hypofractionated radiation therapy (HFRT) combined with immune checkpoint inhibitors (ICIs) in patients with brain metastases (BM) remain controversial. This meta-analysis was performed to compare the efficacy and safety of HFRT with and without ICIs in BM patients. MATERIALS AND METHODS: PubMed, Embase, and Cochrane Library were searched up to 25 December 2018 for studies that compared the efficacy and safety of HFRT with and without ICIs in BM patients. RESULTS: Twenty-four studies involving 2,365 patients were included in this analysis. Compared with those of HFRT without ICIs, the 6-month locoregional recurrence-free survival (LRFS) rate (P = 0.002), 6-month overall survival (OS) rate (P = 0.001), 1-year OS rate (P = 0.001), 2-year OS rate (P = 0.007), and median OS (mOS) (P < 0.001) were significantly improved in combined HFRT and ICI treatment. A trend toward improved 1-year LRFS rate (P = 0.392) and 3-year OS rate (P = 0.266) for the ICI arm was observed compared with the non-ICI arm, although there was no statistically significant difference between the two arms. No significant difference in toxicity was found between the two arms (radionecrosis: P = 0.361; BM hemorrhage: P = 0.738). CONCLUSIONS: Compared with HFRT without ICIs, the combination of these two therapies improved efficacy but did not increase toxicity in patients with BM.

4.
Artigo em Inglês | MEDLINE | ID: mdl-31828045

RESUMO

Objective: To investigate the drug resistance characteristics of Mycobacterium tuberculosis (MTB) isolates from patients with tuberculosis to 12 antituberculous drugs in China. Methods: All clinical isolates of MTB were isolated from patients with tuberculosis in Shanghai Pulmonary Hospital (SPH) during the period from January 1st to December 31th, 2018. Drug susceptibility testing (DST) was performed in micro plates with 12 antituberculous drugs in accordance with relevant guideline. Demographic information, including sex, age, and treatment history was recorded. Results: A total of 1,950 MTB isolates were included in this retrospective study which were isolated from 1,950 patients from 29 regions in China. One thousand six hundred and forty-four were initial treated and 306 were re-treated in the hospital. Two hundred and eight (10.67%, 208/1,950) cases were diagnosed as multidrug-resistant tuberculosis (MDR-TB), from which 74 (4.50%, 74/1,644) cases were initial treated, and the remaining (43.79%, 134/306) were re-treated cases. Besides, the percentage of extensively drug-resistant tuberculosis (XDR-TB) varied in such 3 different groups: 1.64% (32/1,950) in total cases, 0.30% (5/1,644) in initial treated cases and 8.82% (27/306) in re-treated cases. The total resistance rates were as follows: isoniazid (361, 18.51%), streptomycin (302, 15.49%), rifampin (241, 12.36%), ofloxacin (239, 12.26%), moxifloxacin (232, 11.90%), rifabutin (195, 10.00%), ethambutol (100, 5.13%), cycloserine (55, 2.82%), kanamycin (48, 2.46%), ethionamide (40, 2.05%), amikacin (39, 2.00%), and aminosalicylic acid (21, 1.08%). Rates of resistance to any drug in re-treated cases were significantly higher than in initial treated cases. The drug resistance rates of the 12 drugs were higher in males than in females. Patients older than 60 years had significantly lower percentages of MDR/XDR-TB (7.11 and 0.65%) than in younger age groups. The proportion of re-treated cases in Shanghai (11.38%, 88/773) was lower than that in other regions. Meanwhile, the percentages of MDR/XDR-TB in Shanghai (4.79 and 0.65%) were significantly lower than in other regions. Conclusions: In this study, we found higher proportion of MDR/XDR-TB among re-treated cases than initial treated cases in China and the drug resistance rate of tuberculosis varied with age, sex, and region, indicating that standardized anti-tuberculosis treatment can reduce the incidence of drug-resistant tuberculosis and the recurrence of tuberculosis.

5.
Proc Natl Acad Sci U S A ; 116(44): 22393-22398, 2019 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-31611384

RESUMO

Photosynthesis of the Amazon rainforest plays an important role in the regional and global carbon cycles, but, despite considerable in situ and space-based observations, it has been intensely debated whether there is a dry-season increase in greenness and photosynthesis of the moist tropical Amazonian forests. Solar-induced chlorophyll fluorescence (SIF), which is emitted by chlorophyll, has a strong positive linear relationship with photosynthesis at the canopy scale. Recent advancements have allowed us to observe SIF globally with Earth observation satellites. Here we show that forest SIF did not decrease in the early dry season and increased substantially in the late dry season and early part of wet season, using SIF data from the Tropospheric Monitoring Instrument (TROPOMI), which has unprecedented spatial resolution and near-daily global coverage. Using in situ CO2 eddy flux data, we also show that cloud cover rarely affects photosynthesis at TROPOMI's midday overpass, a time when the forest canopy is most often light-saturated. The observed dry-season increases of forest SIF are not strongly affected by sun-sensor geometry, which was attributed as creating a pseudo dry-season green-up in the surface reflectance data. Our results provide strong evidence that greenness, SIF, and photosynthesis of the tropical Amazonian forest increase during the dry season.

6.
Int J Infect Dis ; 81: 91-96, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30738907

RESUMO

OBJECTIVE: To evaluate the diagnostic performance of Xpert MTB/RIF Ultra for EPTB (Extrapulmonary Tuberculosis) patients on different types of extrapulmonary specimens from different anatomic sites. METHODS: Patients with suspected EPTB were prospectively included, extrapulmonary specimens were collected and subjected to culture, Xpert and Xpert Ultra assays in accordance with relevant guidelines. RESULTS: A total of 225 cases were included which contained 200 EPTB cases (43 culture-positive EPTB, 157 culture-negative EPTB which were diagnosed based on pathological results and a satisfied response to anti-TB treatment) and 25 non-EPTB cases. Sensitivities of Xpert Ultra and Xpert for culture-positive cases were 83.7% (95%CI, 68.7-92.7) and 67.4% (95% CI, 51.3-80.5) respectively. Specificities of Xpert Ultra and Xpert were 92.0% (95% CI, 72.5-98.6) and 96.0% (95% CI, 77.7-99.8) respectively. The sensitivities of Xpert Ultra, Xpert and culture for 200 EPTB cases were 52.5% (105/200, 95% CI, 45.4-59.6), 34.0% (68/200, 95% CI, 27.6-41.1) and 21.5% (43/200, 95% CI, 16.2-28.0) respectively. By comparison among different types of specimens, Xpert Ultra can detect 78.9% (56/71) of EPTB on fine-needle aspiration (FNA) tissues which was higher than that on pleural fluid (43.7% (45/103), p<0.05. CONCLUSIONS: Xpert Ultra assay had a higher sensitivity than those of Xpert and culture on extrapulmonary specimens, which could be a promising approach for rapid EPTB diagnosis.


Assuntos
Exsudatos e Transudatos/microbiologia , Técnicas de Diagnóstico Molecular/instrumentação , Mycobacterium tuberculosis/isolamento & purificação , Tuberculose/diagnóstico , Adolescente , Adulto , Idoso , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Técnicas de Diagnóstico Molecular/métodos , Valor Preditivo dos Testes , Estudos Prospectivos , Sensibilidade e Especificidade , Tuberculose/fisiopatologia , Adulto Jovem
7.
ChemSusChem ; 12(4): 858-865, 2019 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-30600929

RESUMO

In this study, nitrogen-doped graphene nanoshells (N-GNS) were developed to support palladium nanoparticles (Pd/N-GNS) as an efficient and recyclable catalyst for the N-allylation reaction. N-GNS was synthesized through a facile hard-template method by using petroleum asphalt, followed by nitrogen doping by thermal annealing with urea, the contents and species of which could be altered by the calcination temperature. Palladium nanoparticles (Pd NPs) with an average diameter of 3.3 nm were homogeneously deposited onto the N-GNS support through a mild solvent-growth approach. The Pd/N-GNS exhibited a superior activity towards the N-allylation reaction, 6-fold higher than that of the pristine graphene nanoshells supporting the palladium catalyst. The Pd/N-GNS could be recycled several times without activity deterioration and metal leaching. The catalytic activity showed a linear correlation relationship with the pyridinic N content. Experimental and theoretical studies reveal strong metal-support interactions between the pyridinic N and palladium species, which can downsize the Pd NPs, modulate the electronic properties, and promote the adsorption of reactant, thereby significantly boosting the catalytic efficiency and stability for the N-allylation process. The present work could help unravel the roles of nitrogen-doped carbon supports and provides a feasible strategy to rationally design superior palladium catalysts for chemical transformations.

8.
Glob Chang Biol ; 24(12): 5655-5667, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30215879

RESUMO

Woody plant encroachment (WPE) into grasslands has been occurring globally and may be accelerated by climate change in the future. This land cover change is expected to alter the carbon and water cycles, but it remains uncertain how and to what extent the carbon and water cycles may change with WPE into grasslands under current climate. In this study, we examined the difference of vegetation indices (VIs), evapotranspiration (ET), gross primary production (GPP), and solar-induced chlorophyll fluorescence (SIF) during 2000-2010 between grasslands and juniper-encroached grasslands. We also quantitatively assessed the changes of GPP and ET for grasslands with different proportions of juniper encroachment (JWPE). Our results suggested that JWPE increased the GPP, ET, greenness-related VIs, and SIF of grasslands. Mean annual GPP and ET were, respectively, ~55% and ~45% higher when grasslands were completely converted into juniper forests under contemporary climate during 2000-2010. The enhancement of annual GPP and ET for grasslands with JWPE varied over years ranging from about +20% GPP (~+30% for ET) in the wettest year (2007) to about twice as much GPP (~+55% for ET) in the severe drought year (2006) relative to grasslands without encroachment. Additionally, the differences in GPP and ET showed significant seasonal dynamics. During the peak growing season (May-August), GPP and ET for grasslands with JWPE were ~30% and ~40% higher on average. This analysis provided insights into how and to what degree carbon and water cycles were impacted by JWPE, which is vital to understanding how JWPE and ecological succession will affect the regional and global carbon and water budgets in the future.


Assuntos
Ciclo do Carbono , Mudança Climática , Florestas , Pradaria , Juniperus/fisiologia , Água , Secas , Transpiração Vegetal , Estações do Ano , Luz Solar
9.
J Neurooncol ; 137(1): 49-56, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29170906

RESUMO

Administration of bevacizumab to patients with brain metastases (BM) is controversial due to concerns about the increased risk of intracranial hemorrhage (ICH). This meta-analysis assessed whether the risk of ICH increases in BM patients receiving treatments that contain bevacizumab versus without. PubMed, Embase, Cochrane Library and annual meeting abstracts of the American Society of Clinical Oncology up to 13 November 2016 were searched for studies that referred to ICH complications due to bevacizumab in patients with BM. Eight studies involving 8713 patients were included in this analysis. Compared with the control arm without bevacizumab, the bevacizumab treatment arm did not exhibit a significant increase in ICH [odds ratio (OR) 1.20; 95% confidence intervals (CI) 0.69-2.09; P = 0.53]. Subgroup analyses with retrospective studies showed a similar result, although subgroup analyses with prospective studies failed. This meta-analysis revealed that bevacizumab does not significantly increase the risk of ICH in solid tumor patients with BM.


Assuntos
Antineoplásicos Imunológicos/efeitos adversos , Bevacizumab/efeitos adversos , Neoplasias Encefálicas/complicações , Hemorragias Intracranianas/induzido quimicamente , Neoplasias Encefálicas/secundário , Feminino , Humanos , Hemorragias Intracranianas/complicações , Masculino , Razão de Chances , Resultado do Tratamento
10.
Sci Rep ; 7(1): 14963, 2017 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-29097731

RESUMO

The gross primary production (GPP) of vegetation in urban areas plays an important role in the study of urban ecology. It is difficult however, to accurately estimate GPP in urban areas, mostly due to the complexity of impervious land surfaces, buildings, vegetation, and management. Recently, we used the Vegetation Photosynthesis Model (VPM), climate data, and satellite images to estimate the GPP of terrestrial ecosystems including urban areas. Here, we report VPM-based GPP (GPPvpm) estimates for the world's ten most populous megacities during 2000-2014. The seasonal dynamics of GPPvpm during 2007-2014 in the ten megacities track well that of the solar-induced chlorophyll fluorescence (SIF) data from GOME-2 at 0.5° × 0.5° resolution. Annual GPPvpm during 2000-2014 also shows substantial variation among the ten megacities, and year-to-year trends show increases, no change, and decreases. Urban expansion and vegetation collectively impact GPP variations in these megacities. The results of this study demonstrate the potential of a satellite-based vegetation photosynthesis model for diagnostic studies of GPP and the terrestrial carbon cycle in urban areas.


Assuntos
Clorofila/metabolismo , Fotossíntese , Plantas/metabolismo , Ciclo do Carbono , Ecossistema , Fluorescência , Modelos Biológicos , Desenvolvimento Vegetal , Luz Solar , Urbanização
11.
Sci Data ; 4: 170165, 2017 10 24.
Artigo em Inglês | MEDLINE | ID: mdl-29064464

RESUMO

Accurate estimation of the gross primary production (GPP) of terrestrial vegetation is vital for understanding the global carbon cycle and predicting future climate change. Multiple GPP products are currently available based on different methods, but their performances vary substantially when validated against GPP estimates from eddy covariance data. This paper provides a new GPP dataset at moderate spatial (500 m) and temporal (8-day) resolutions over the entire globe for 2000-2016. This GPP dataset is based on an improved light use efficiency theory and is driven by satellite data from MODIS and climate data from NCEP Reanalysis II. It also employs a state-of-the-art vegetation index (VI) gap-filling and smoothing algorithm and a separate treatment for C3/C4 photosynthesis pathways. All these improvements aim to solve several critical problems existing in current GPP products. With a satisfactory performance when validated against in situ GPP estimates, this dataset offers an alternative GPP estimate for regional to global carbon cycle studies.

12.
Acta Derm Venereol ; 97(4): 472-477, 2017 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-27840887

RESUMO

Cutaneous tuberculosis (CTB) is probably underreported due to difficulties in detection and diagnosis. To address this issue, genotypes of Mycobacterium tuberculosis strains isolated from 30 patients with CTB were mapped at multiple loci, namely, RD105 deletions, spacer oligonucleotides, and Mycobacterial Interspersed Repetitive Unit-Variable Number Tandem Repeats (MIRU-VNTRs). Fifty-eight strains of pulmonary tuberculosis (PTB) were mapped as experimental controls. Drug resistance-associated gene mutations were determined by amplicon sequencing of target regions within 7 genes. Beijing family isolates were the most prevalent strains in CTB and PTB. MIRU-VNTR typing separated the Beijing strains from the non-Beijing strains, and the majority of CTB could be separated from PTB counterparts. Drug resistance determining regions showed only one CTB strain expressing isomazid resistance. Thus, while the CTB strains belonged to the same phylogenetic lineages and sub-lineages as the PTB strains, they differed at the level of several MIRU-VNTRs and in the proportion of drug resistance.


Assuntos
DNA Bacteriano/genética , Mycobacterium/genética , Pele/microbiologia , Tuberculose Cutânea/microbiologia , Adulto , Antituberculosos/uso terapêutico , Estudos de Casos e Controles , China/epidemiologia , DNA Bacteriano/isolamento & purificação , Farmacorresistência Bacteriana/genética , Feminino , Genótipo , Humanos , Sequências Repetitivas Dispersas , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Repetições Minissatélites , Técnicas de Diagnóstico Molecular , Mycobacterium/efeitos dos fármacos , Mycobacterium/isolamento & purificação , Fenótipo , Filogenia , Tuberculose Cutânea/diagnóstico , Tuberculose Cutânea/tratamento farmacológico , Tuberculose Cutânea/epidemiologia
13.
Sci Rep ; 6: 39748, 2016 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-28008960

RESUMO

Carbon uptake by terrestrial ecosystems is increasing along with the rising of atmospheric CO2 concentration. Embedded in this trend, recent studies suggested that the interannual variability (IAV) of global carbon fluxes may be dominated by semi-arid ecosystems, but the underlying mechanisms of this high variability in these specific regions are not well known. Here we derive an ensemble of gross primary production (GPP) estimates using the average of three data-driven models and eleven process-based models. These models are weighted by their spatial representativeness of the satellite-based solar-induced chlorophyll fluorescence (SIF). We then use this weighted GPP ensemble to investigate the GPP variability for different aridity regimes. We show that semi-arid regions contribute to 57% of the detrended IAV of global GPP. Moreover, in regions with higher GPP variability, GPP fluctuations are mostly controlled by precipitation and strongly coupled with evapotranspiration (ET). This higher GPP IAV in semi-arid regions is co-limited by supply (precipitation)-induced ET variability and GPP-ET coupling strength. Our results demonstrate the importance of semi-arid regions to the global terrestrial carbon cycle and posit that there will be larger GPP and ET variations in the future with changes in precipitation patterns and dryland expansion.

14.
Tuberculosis (Edinb) ; 95(6): 695-700, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26542224

RESUMO

OBJECTIVES: Mixed infections of Mycobacterium tuberculosis strains have attracted more attention due to their increasing frequencies worldwide, especially in the areas of high tuberculosis (TB) prevalence. In this study, we accessed the rates of mixed infections in a setting with high TB prevalence in Inner Mongolia Autonomous Region of China. METHODS: A total of 384 M. tuberculosis isolates from the local TB hospital were subjected to mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) typing method. The single clones of the strains with mixed infections were separated by subculturing them on the Löwenstein-Jensen medium. RESULTS: Of these 384 isolates, twelve strains (3.13%) were identified as mixed infections by MIRU-VNTR. Statistical analysis indicated that demographic characteristics and drug susceptibility profiles showed no statistically significant association with the mixed infections. We further subcultured the mixed infection strains and selected 30 clones from the subculture for each mixed infection. Genotyping data revealed that eight (8/12, 66.7%) strains with mixed infections had converted into single infection through subculture. The higher growth rate was associated with the increasing proportion of variant subpopulation through subculture. CONCLUSIONS: In conclusion, by using the MIRU-VNTR method, we demonstrate that the prevalence of mixed infections in Inner Mongolia is low. Additionally, our findings reveal that the subculture changes the population structures of mixed infections, and the subpopulation with higher growth rate show better fitness, which is associated with high proportion among the population structure after subculture. This study highlights that the use of clinical specimens, rather than subcultured isolates, is preferred to estimate the prevalence of mixed infections in the specific regions.


Assuntos
Coinfecção/microbiologia , DNA Bacteriano/genética , Mycobacterium tuberculosis/genética , Tuberculose/microbiologia , China/epidemiologia , Coinfecção/diagnóstico , Coinfecção/epidemiologia , DNA Bacteriano/isolamento & purificação , Genótipo , Humanos , Testes de Sensibilidade Microbiana , Repetições Minissatélites , Técnicas de Diagnóstico Molecular , Mycobacterium tuberculosis/classificação , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/crescimento & desenvolvimento , Mycobacterium tuberculosis/isolamento & purificação , Fenótipo , Prevalência , Fatores de Risco , Tuberculose/diagnóstico , Tuberculose/epidemiologia
15.
Sci Rep ; 5: 13799, 2015 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-26347998

RESUMO

Water use efficiency (WUE) measures the trade-off between carbon gain and water loss of terrestrial ecosystems, and better understanding its dynamics and controlling factors is essential for predicting ecosystem responses to climate change. We assessed the magnitude, spatial patterns, and trends of WUE of China's terrestrial ecosystems and its responses to drought using a process-based ecosystem model. During the period from 2000 to 2011, the national average annual WUE (net primary productivity (NPP)/evapotranspiration (ET)) of China was 0.79 g C kg(-1) H2O. Annual WUE decreased in the southern regions because of the decrease in NPP and the increase in ET and increased in most northern regions mainly because of the increase in NPP. Droughts usually increased annual WUE in Northeast China and central Inner Mongolia but decreased annual WUE in central China. "Turning-points" were observed for southern China where moderate and extreme droughts reduced annual WUE and severe drought slightly increased annual WUE. The cumulative lagged effect of drought on monthly WUE varied by region. Our findings have implications for ecosystem management and climate policy making. WUE is expected to continue to change under future climate change particularly as drought is projected to increase in both frequency and severity.


Assuntos
Secas , Ecossistema , Abastecimento de Água , Água , China , Análise Espacial
16.
Antimicrob Agents Chemother ; 59(4): 2045-50, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25605360

RESUMO

Ethambutol (EMB) plays a pivotal role in the chemotherapy of drug-resistant tuberculosis (TB), including multidrug-resistant tuberculosis (MDR-TB). Resistance to EMB is considered to be caused by mutations in the embCAB operon (embC, embA, and embB). In this study, we analyzed the embCAB mutations among 139 MDR-TB isolates from China and found a possible association between embCAB operon mutation and EMB resistance. Our data indicate that 56.8% of MDR-TB isolates are resistant to EMB, and 82.2% of EMB-resistant isolates belong to the Beijing family. Overall, 110 (79.1%) MDR-TB isolates had at least one mutation in the embCAB operon. The majority of mutations were present in the embB gene and the embA upstream region, which also displayed significant correlations with EMB resistance. The most common mutations occurred at codon 306 in embB (embB306), followed by embB406, embA(-16), and embB497. Mutations at embB306 were associated with EMB resistance. DNA sequencing of embB306-497 was the best strategy for detecting EMB resistance, with 89.9% sensitivity, 58.3% specificity, and 76.3% accuracy. Additionally, embB306 had limited value as a candidate predictor for EMB resistance among MDR-TB infections in China.


Assuntos
Antituberculosos/farmacologia , Proteínas de Bactérias/genética , Etambutol/farmacologia , Proteínas de Membrana/genética , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/genética , Pentosiltransferases/genética , Tuberculose Resistente a Múltiplos Medicamentos/genética , Tuberculose/microbiologia , China , DNA Bacteriano/genética , Humanos , Testes de Sensibilidade Microbiana
17.
Guang Pu Xue Yu Guang Pu Fen Xi ; 34(8): 2218-24, 2014 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-25474965

RESUMO

A three-dimensional Gabor filter was developed for classification of hyperspectral remote sensing image. This method is based on the characteristics of hyperspectral image and the principle of texture extraction with 2-D Gabor filters. Three-dimensional Gabor filter is able to filter all the bands of hyperspectral image simultaneously, capturing the specific responses in different scales, orientations, and spectral-dependent properties from enormous image information, which greatly reduces the time consumption in hyperspectral image texture extraction, and solve the overlay difficulties of filtered spectrums. Using the designed three-dimensional Gabor filters in different scales and orientations, Hyperion image which covers the typical area of Qi Lian Mountain was processed with full bands to get 26 Gabor texture features and the spatial differences of Gabor feature textures corresponding to each land types were analyzed. On the basis of automatic subspace separation, the dimensions of the hyperspectral image were reduced by band index (BI) method which provides different band combinations for classification in order to search for the optimal magnitude of dimension reduction. Adding three-dimensional Gabor texture features successively according to its discrimination to the given land types, supervised classification was carried out with the classifier support vector machines (SVM). It is shown that the method using three-dimensional Gabor texture features and BI band selection based on automatic subspace separation for hyperspectral image classification can not only reduce dimensions; but also improve the classification accuracy and efficiency of hyperspectral image.

18.
Antimicrob Agents Chemother ; 58(4): 1997-2005, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24419342

RESUMO

To investigate the molecular characterization of multidrug-resistant tuberculosis (MDR-TB) isolates from China and the association of specific mutations conferring drug resistance with strains of different genotypes, we performed spoligotyping and sequenced nine loci (katG, inhA, the oxyR-ahpC intergenic region, rpoB, tlyA, eis, rrs, gyrA, and gyrB) for 128 MDR-TB isolates. Our results showed that 108 isolates (84.4%) were Beijing family strains, 64 (59.3%) of which were identified as modern Beijing strains. Compared with the phenotypic data, the sensitivity and specificity of DNA sequencing were 89.1% and 100.0%, respectively, for isoniazid (INH) resistance, 93.8% and 100.0% for rifampin (RIF) resistance, 60.0% and 99.4% for capreomycin (CAP) resistance, 84.6% and 99.4% for kanamycin (KAN) resistance, and 90.0% and 100.0% for ofloxacin (OFX) resistance. The most prevalent mutations among the MDR-TB isolates were katG315, inhA15, rpoB531, -526, and -516, rrs1401, eis-10, and gyrA94, -90, and -91. Furthermore, there was no association between specific resistance-conferring mutations and the strain genotype. These findings will be helpful for the establishment of rapid molecular diagnostic methods to be implemented in China.


Assuntos
Antituberculosos/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Capreomicina/farmacologia , Genótipo , Humanos , Isoniazida/farmacologia , Canamicina/farmacologia , Testes de Sensibilidade Microbiana , Mycobacterium tuberculosis/metabolismo , Ofloxacino/farmacologia , Rifampina/farmacologia , Tuberculose Resistente a Múltiplos Medicamentos/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA