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1.
Lancet Infect Dis ; 20(8): 911-919, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32353347

RESUMO

BACKGROUND: Rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Wuhan, China, prompted heightened surveillance in Shenzhen, China. The resulting data provide a rare opportunity to measure key metrics of disease course, transmission, and the impact of control measures. METHODS: From Jan 14 to Feb 12, 2020, the Shenzhen Center for Disease Control and Prevention identified 391 SARS-CoV-2 cases and 1286 close contacts. We compared cases identified through symptomatic surveillance and contact tracing, and estimated the time from symptom onset to confirmation, isolation, and admission to hospital. We estimated metrics of disease transmission and analysed factors influencing transmission risk. FINDINGS: Cases were older than the general population (mean age 45 years) and balanced between males (n=187) and females (n=204). 356 (91%) of 391 cases had mild or moderate clinical severity at initial assessment. As of Feb 22, 2020, three cases had died and 225 had recovered (median time to recovery 21 days; 95% CI 20-22). Cases were isolated on average 4·6 days (95% CI 4·1-5·0) after developing symptoms; contact tracing reduced this by 1·9 days (95% CI 1·1-2·7). Household contacts and those travelling with a case were at higher risk of infection (odds ratio 6·27 [95% CI 1·49-26·33] for household contacts and 7·06 [1·43-34·91] for those travelling with a case) than other close contacts. The household secondary attack rate was 11·2% (95% CI 9·1-13·8), and children were as likely to be infected as adults (infection rate 7·4% in children <10 years vs population average of 6·6%). The observed reproductive number (R) was 0·4 (95% CI 0·3-0·5), with a mean serial interval of 6·3 days (95% CI 5·2-7·6). INTERPRETATION: Our data on cases as well as their infected and uninfected close contacts provide key insights into the epidemiology of SARS-CoV-2. This analysis shows that isolation and contact tracing reduce the time during which cases are infectious in the community, thereby reducing the R. The overall impact of isolation and contact tracing, however, is uncertain and highly dependent on the number of asymptomatic cases. Moreover, children are at a similar risk of infection to the general population, although less likely to have severe symptoms; hence they should be considered in analyses of transmission and control. FUNDING: Emergency Response Program of Harbin Institute of Technology, Emergency Response Program of Peng Cheng Laboratory, US Centers for Disease Control and Prevention.

2.
PLoS Negl Trop Dis ; 14(3): e0008085, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32196496

RESUMO

BACKGROUND: The epidemic of hand, foot, and mouth disease (HFMD) has become a severe public health problem in the world and has also brought a high economic and health burden. Furthermore, the prevalence of HFMD varies significantly among different locations. However, there have been few investigations of the effects of socioeconomic factors and air pollution factors on the incidence of HFMD. METHODS: This study collected data on HFMD in Shenzhen, China, from 2012 to 2015. We selected eleven factors as potential risk factors for HFMD. A Bayesian spatiotemporal model was used to quantify the influence of the factors on HFMD and to identify the relative risks in different districts. RESULTS: The risk factors of HFMD were the population, population density, concentration of SO2, and concentration of NO2. The relative risks (RRs) were 1.00473 (95% CI: 1.00059-1.00761), 1.00010 (95% CI: 1.00002-1.00016), 1.00215 (95% CI: 1.00170-1.00232) and 1.00058 (95% CI: 1.00028-1.00078), respectively. The protective factors against HFMD were the per capita GDP, the number of public kindergartens, the concentration of PM10, and the concentration of O3. The RRs were 0.98840 (95% CI: 0.98660-0.99026), 0.97686 (95% CI: 0.96946-0.98403), 0.99108 (95% CI: 0.98551-0.99840) and 0.99587 (95% CI: 0.99534-0.99610), respectively. The risk of incidence in Longgang district and Pingshan district decreased, while the risk of incidence in Baoan district increased. CONCLUSIONS: Studies have confirmed that socioeconomic factors and air pollution factors have an impact on the incidence of HFMD in Shenzhen, China. The results will be of great practical significance to local authorities, which is conducive to accurate prevention and can be used to formulate HFMD early warning systems.


Assuntos
Doença de Mão, Pé e Boca/epidemiologia , Poluição do Ar , Teorema de Bayes , Criança , Pré-Escolar , China/epidemiologia , Exposição Ambiental , Feminino , Humanos , Incidência , Lactente , Masculino , Medição de Risco , Fatores Socioeconômicos , Análise Espaço-Temporal
3.
J Pharm Biomed Anal ; 182: 113110, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32004768

RESUMO

Callicarpa nudiflora, belonging to the family Verbenaceae, is widely used to treat inflammation caused by bacterial infection.However, the underlying active substances of C. nudiflora against inflammation remains obscure. In this work, an ultra high-performance liquid chromatography (UHPLC) coupled with quadrupole time-of-flight mass spectrometry method was developed to characterize the ingredients in C. nudiflora, and a validated UHPLC coupled with triple quadrupole tandem mass spectrometry method was applied to quantify major components. As a result, a total of 96 chemical compounds were identified in C. nudiflora, and 26 compounds of them were further quantified in 34 batches of C. nudiflora. Based on the identified components from C. nudiflora, a compound-target network for the anti-inflammation effect was constructed by reverse docking target prediction, disease associated genes screening in DisGeNET and the protein-protein interaction from STRING. The compound-target network showed that C. nudiflora might exert anti-inflammation effect on the target of complement 3 and 5 in the pathway of cells and molecules involved in local acute inflammatory response, and 16 effective candidate compounds were found such as catalpol, acteoside, rutin, etc. This study provided an opportunity to deepen the understanding of the chemical composition and the potential anti-inflammatory mechanism of C. nudiflora.

4.
Microbiol Res ; 223-225: 88-98, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31178056

RESUMO

CodY and (p)ppGpp synthetases are two important global regulators of bacteria. In some pathogens, such as Listeria monocytogenes, the GTP pool links these two regulatory systems, and introducing a codY mutant into the ΔrelA strain restored the pathogenicity of the attenuated ΔrelA mutant. In previous studies, we identified the (p)ppGpp synthetases (RelA and RelQ) and CodY of Streptococcus suis. To understand the interrelationships between these two regulators in S. suis, a ΔrelAΔrelQΔcodY mutant was constructed, and its growth, morphology, and pathogenicity were evaluated. Compared with ΔrelAΔrelQ, ΔcodY, its growth was very slow, but its chain length was partly restored to the wild-type length and its capsule became thick and rough. The adherence, invasion ability, and resistance to whole-blood killing in vitro of ΔrelAΔrelQΔcodY and its lethality and colonization ability in mice were clearly reduced, which differs from the effects of these mutations in L. monocytogenes. An analysis of gene expression showed that CodY interacted with the relA promoter in a GTP-independent manner to positively regulate the expression of relA. The introduction of a codY mutant into the ΔrelAΔrelQ strain further reduced the expression of virulence factors, which suggests a novel interaction between the (p)ppGpp synthetases and CodY. This study extends our understanding of the relationship between the (p)ppGpp-mediated stringent response and the regulation of CodY in S. suis.


Assuntos
Regulação Bacteriana da Expressão Gênica , Ligases/metabolismo , Streptococcus suis/citologia , Streptococcus suis/metabolismo , Streptococcus suis/patogenicidade , Fatores de Transcrição/metabolismo , Transcriptoma , Adesinas Bacterianas/genética , Animais , Proteínas de Bactérias/genética , Modelos Animais de Doenças , Feminino , Guanosina Trifosfato/metabolismo , Ligases/genética , Listeria monocytogenes/genética , Listeria monocytogenes/metabolismo , Listeria monocytogenes/patogenicidade , Camundongos , Mutação , Regiões Promotoras Genéticas , Infecções Estreptocócicas/microbiologia , Streptococcus suis/genética , Fatores de Transcrição/genética , Fatores de Virulência/genética , Fatores de Virulência/metabolismo
5.
J Biomed Inform ; 93: 103144, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30905736

RESUMO

Influenza rapidly spreads in seasonal epidemics and imposes a considerable economic burden on hospitals and other healthcare costs. Thus, predicting the propagation of influenza accurately is crucial in preventing influenza outbreaks and protecting public health. Most current studies focus on the spread simulation of influenza. However, few studies have investigated the dependencies between meteorological variables and influenza activity. This study develops a non-parametric model based on Gaussian process regression for influenza prediction considering meteorological effect to capture temporal dependencies hidden in influenza time series. To identify the most explanatory external variables, L1-regularization is applied to identify meteorology factor subsets, and three types of covariance functions are designed to characterize non-stationary and periodic behavior in influenza activity. The dependencies of diseases and meteorology are modeled through the designed cross-covariance function. A real case in Shenzhen, China was studied to validate our proposed model along with comparisons to recently developed multivariate statistical models for influenza prediction. Results show that our proposed influenza prediction approach achieves superior performance in terms of one-week-ahead prediction of influenza-like illness.

6.
Artigo em Inglês | MEDLINE | ID: mdl-30708969

RESUMO

Background: China is at its most important stage of air pollution control. Research on the association between air pollutants and human health is very important and necessary. The purpose of this study was to evaluate the association between PM2.5 concentrations and residents' mortality and to compare the effect of PM2.5 on the different diseases, accidental deaths, sex or age of residents from high polluted areas with less polluted areas. Methods: The semi-parametric generalized additive model (GAM) with Poisson distribution of time series analysis was used. The excess risk (ER) of mortality with the incremental increase of 10 µg/m³ in PM2.5 concentration was calculated. Concentration-response relationship curves and autocorrelation between different lags of PM2.5 were also evaluated. Results: PM2.5 exposure was significantly associated with the mortality of residents. The strongest ERs per 10 µg/m³ increase in PM2.5 were 0.74% (95% CI: 0.11⁻1.38%) for all-cause, 0.67% (95% CI: 0.01⁻1.33%) for non-accidental, 1.81% (95% CI: 0.22⁻3.42%) for accidental, 3.04% (95% CI: 0.60⁻5.55%) for total respiratory disease, 6.38% (95% CI: 2.78⁻10.11%) for chronic lower respiratory disease (CLRD), 8.24% (95% CI: 3.53⁻13.17%) for chronic obstructive pulmonary disease (COPD), 1.04% (95% CI: 0.25⁻1.84%) for male and 1.32% (95% CI: 0.46⁻2.19%) for elderly. Furthermore, important information on the concentration-response relationship curves was provided. Conclusions: PM2.5 can increase the risk of residents' mortality, even in places with less air pollution and developed economy in China.


Assuntos
Poluentes Atmosféricos/toxicidade , Exposição por Inalação/efeitos adversos , Exposição por Inalação/estatística & dados numéricos , Mortalidade , Material Particulado/toxicidade , Poluentes Atmosféricos/química , China , Cidades , Relação Dose-Resposta a Droga , Humanos , Tamanho da Partícula , Material Particulado/química , Distribuição de Poisson
7.
Sci Total Environ ; 652: 1013-1021, 2019 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-30380469

RESUMO

Hand, foot and mouth disease (HFMD) is a public health issue in China, and its incidence in Guangdong Province is higher than the national average. Previous studies have found climatic factors have an influential role in the transmission of HFMD. Internet search technology has been shown to predict some infectious disease epidemics and is a potential resource in tracking epidemics in countries where the use of Internet search index data is prevalent. This study aims to improve the prediction of HFMD in two Chinese cities, Shantou and Shenzhen in Guangdong Province, applying both meteorological data and Baidu search indices to create a HFMD forecasting model. To this end, the relationship between meteorological factors and HFMD was found to be linear in both cities, while the relationship between search engine data and HFMD was not consistent. The results of our study suggest that using both Internet search and meteorological data can improve the prediction of HFMD incidence. Using comparative analysis of both cities, we posit that improved quality search indices enhance prediction of HFMD.


Assuntos
Doença de Mão, Pé e Boca/epidemiologia , Conceitos Meteorológicos , China/epidemiologia , Previsões , Humanos , Incidência , Internet , Meteorologia , Prevalência , Saúde Pública
8.
Zhongguo Gu Shang ; 31(12): 1168-1171, 2018 Dec 25.
Artigo em Chinês | MEDLINE | ID: mdl-30583661

RESUMO

OBJECTIVE: To evaluate the clinical value of contralateral supplementary puncture in unilateral percutaneous vertebroplasty(PVP) with poor cement dispersion. METHODS: From January 2015 to December 2016, PVP was performed unilaterally in 285 patients(319 vertebrae) with osteoporotic compression fractures(OVCF). Contralateral percutaneous puncture was performed in 13 patients with poor cement dispersion. Among the patients, 5 cases were male and 8 patients were female, ranging in age from 63 to 88 years old; 1 case of T11, 4 cases of T12, 3 cases of L1, 2 cases of L2, 1 case of L3, and 2 cases of L5. The time from injury to operation ranged from 1 to 16 days. The VAS score, ODI score, residual low back pain and loss of vertebral height were observed. RESULTS: The VAS score and ODI score of 13 patients who underwent contralateral supplementary puncture were significantly improved (P<0.01), and there was no postoperative residual low back pain. During the follow-up period, there was no significant difference in the height loss between the two sides of the vertebral body (0.35 to 3.69 mm on the original puncture side and 0.59 to 3.66 mm on the supplementary puncture side). CONCLUSIONS: For unilateral PVP with poor cement dispersion, contralateral puncture can reduce the occurrence of postoperative residual pain; at the same time, can reduce the difference between the loss of height on both sides of the vertebral body, and then prevent the occurrence of lateral vertebral deformity, which is a safe and reliable method.


Assuntos
Fraturas por Compressão , Fraturas por Osteoporose , Fraturas da Coluna Vertebral , Vertebroplastia , Idoso , Idoso de 80 Anos ou mais , Cimentos para Ossos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Punções , Estudos Retrospectivos , Resultado do Tratamento
9.
Biosci Trends ; 12(5): 450-455, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30473551

RESUMO

Hand, foot, and mouth disease (HFMD) is caused by a group of enteroviruses. It infects millions of children in the Southeast Asian area. An accurate forecasting of outbreaks of HFMD could facilitate public health officials to suggest public health actions earlier. Many researchers tried to develop an early warning system for HFMD to lower the damage caused by a HFMD outbreak. The research data based on daily level could help figure out the relationship between HFMD and environmental factors, but nevertheless is difficult to collect. In this study, we collected the daily clinical data from the Shenzhen Health Information Center and multiple environmental factors to analyze the outbreaks of HFMD. Considering the incubation period of HFMD, we fed the previous 60 days' HFMD rates, 7 days' temperature factors and 7 days' air-quality factors into the tree model, XGBoost. The following conclusions were drawn in this study: i) Compared with the model only using the previous HFMD rate and temperature factors, the addition of the air-quality factors could make the model better, improving MAE nearly 16.7%. ii) By analyzing the Pearson correlation, we found that the temperature showed a positive correlation and the air quality showed a negative correlation for the HFMD outbreaks. Improving the air quality, especially decreasing PM2.5 and PM10 could decrease the risk of HFMD outbreaks.


Assuntos
Controle de Doenças Transmissíveis , Doença de Mão, Pé e Boca/epidemiologia , Infectologia/métodos , Poluição do Ar , Algoritmos , China/epidemiologia , Clima , Coleta de Dados , Surtos de Doenças , Previsões , Humanos , Aprendizado de Máquina , Modelos Estatísticos , Morbidade , Saúde Pública , Análise de Regressão , Temperatura , Tempo (Meteorologia)
10.
Conf Proc IEEE Eng Med Biol Soc ; 2018: 1148-1151, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-30440594

RESUMO

Despite traditional risk factors such as aging and hyperlipemia for cardiovascular disease (CVD) mortality, many studies have also confirmed that both hot and cold ambient temperatures are associated with CVD mortality. This paper aims to explore the effects of consecutive moderately cold days on CVD mortality in the warm city Shenzhen during relatively cold months from 2011 to 2015. In this study, totally there were 4589 CVD death cases among the residents during a total of 24 relatively cold months. Effects of consecutive cold days on CVD mortality was evaluated by the daily percent increase of CVD mortality. Three temperature thresholds were selected, which were 15°, 14°, and 13°, respectively. The results showed that when the cold weather lasted 5 days and onwards, CVD mortality showed a continuous increment. When the temperature thresholds were 15°, 14°, or 13°, percent increase of CVD mortality at the consecutive 6th cold day reached 22%, 21%, and 24% respectively, and 26%, 38%, 33% at the consecutive 10th cold day, respectively. Thus, the consecutive moderately cold days in warm regions had continuous and accumulative negative effects on CVD mortality. The study may help local government to take timely prevention measures for moderately cold temperatures and thus to protect the wellbeing for the public.


Assuntos
Doenças Cardiovasculares , China , Cidades , Temperatura Baixa , Temperatura Alta , Humanos , Mortalidade
11.
Biosci Rep ; 38(5)2018 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-30042167

RESUMO

The mechanism of action by which oxidative stress induces granulosa cell apoptosis, which plays a vital role in initiating follicular atresia, is not well understood. In the present study, the effect of 3-nitropropionic acid (3-NPA) on oxidative stress and apoptosis in granulosa cells in geese was investigated. Our results showed that treatment with 3-NPA at 5.0 mmol/l for 24 h increased intracellular reactive oxygen species (ROS) production by 25.4% and decreased granulosa cell viability by 45.5% (P<0.05). Catalase and glutathione peroxidase gene expression levels in granulosa cells treated with 3-NPA were 1.32- and 0.49-fold compared with those of the control cells, respectively (P <0.05). A significant decrease in the expression level of B-cell lymphoma 2 (Bcl-2) protein and remarkable increases in the levels of Bax, p53 and cleaved-Caspase 3 proteins and the ratio of Bax/Bcl-2 expression in granulosa cells treated with 3-NPA were observed (P<0.05). Furthermore, a 38.43% increase in the percentage of early apoptotic cells was also observed in granulosa cells treated with 3-NPA (P<0.05). Moreover, the expression levels of NF-κB, Nrf2, Fhc, Hspa2 and Ho-1 in granulosa cells treated with 3-NPA were elevated 4.36-, 1.63-, 3.62-, 27.54- and 10.48-fold compared with those of the control cells (P<0.05), respectively. In conclusion, the present study demonstrates that treatment with 3-NPA induces ROS production and apoptosis and inhibits the viability of granulosa cells in geese. Furthermore, 3-NPA triggers increases in the expression of cleaved-Caspase 3 protein and the ratio of Bax/Bcl-2 expression, and induces the early apoptosis of granulosa cells.


Assuntos
Células da Granulosa/efeitos dos fármacos , Nitrocompostos/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Propionatos/farmacologia , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Caspase 3/genética , Catalase/genética , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Feminino , Gansos , Regulação da Expressão Gênica/efeitos dos fármacos , Glutationa Peroxidase/genética , Células da Granulosa/citologia , Células da Granulosa/fisiologia , Estresse Oxidativo/genética , Proteínas Proto-Oncogênicas c-bcl-2/genética , Espécies Reativas de Oxigênio/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína X Associada a bcl-2/genética
12.
Artigo em Inglês | MEDLINE | ID: mdl-29360738

RESUMO

Nowadays, air pollution is a severe environmental problem in China. To investigate the effects of ambient air pollution on health, a time series analysis of daily outpatient and inpatient visits in 2015 were conducted in Shenzhen (China). Generalized additive model was employed to analyze associations between six air pollutants (namely SO2, CO, NO2, O3, PM10, and PM2.5) and daily outpatient and inpatient visits after adjusting confounding meteorological factors, time and day of the week effects. Significant associations between air pollutants and two types of hospital visits were observed. The estimated increase in overall outpatient visits associated with each 10 µg/m³ increase in air pollutant concentration ranged from 0.48% (O3 at lag 2) to 11.48% (SO2 with 2-day moving average); for overall inpatient visits ranged from 0.73% (O3 at lag 7) to 17.13% (SO2 with 8-day moving average). Our results also suggested a heterogeneity of the health effects across different outcomes and in different populations. The findings in present study indicate that even in Shenzhen, a less polluted area in China, significant associations exist between air pollution and daily number of overall outpatient and inpatient visits.


Assuntos
Poluentes Atmosféricos/efeitos adversos , Poluição do Ar/efeitos adversos , Assistência Ambulatorial/estatística & dados numéricos , Hospitais/estatística & dados numéricos , Material Particulado/efeitos adversos , China , Humanos , Pacientes Internados , Conceitos Meteorológicos , Pacientes Ambulatoriais
13.
Reprod Biol ; 18(1): 60-65, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29336947

RESUMO

Spermine synthase (SPMS), which converts spermidine into spermine, is essential for normal cell growth and development processes in humans and other mammals, but the molecular characterization and expression profiling of the SPMS gene remain undetermined in goose tissues and ovarian follicles. In this study, the SPMS cDNA sequence of the Sichuan white goose was cloned and analysed, and SPMS mRNA expression was profiled in various tissues and ovarian follicles. The results showed that the open reading frame of the SPMS cDNA sequence was 1092 bp in length, encoding 363 amino acids with a molecular weight of 41 kDa. Among all the examined tissues, SPMS expression was highest in the spleen and cerebrum and lowest in the breast and thigh muscles. SPMS expression in the F1 follicle was significantly higher than that in the POF (except for POF2) (P < 0.05). Our results indicate that SPMS might play an important role in follicular development and ovulation.


Assuntos
Proteínas Aviárias/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Ovário/enzimologia , RNA Mensageiro/metabolismo , Espermina Sintase/metabolismo , Sequência de Aminoácidos , Animais , Proteínas Aviárias/química , Proteínas Aviárias/genética , Sequência de Bases , Cérebro/enzimologia , Cérebro/metabolismo , China , Biologia Computacional , DNA Complementar/química , DNA Complementar/metabolismo , Feminino , Gansos , Perfilação da Expressão Gênica/veterinária , Peso Molecular , Proteínas do Tecido Nervoso/química , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Neurônios/enzimologia , Neurônios/metabolismo , Fases de Leitura Aberta , Especificidade de Órgãos , Folículo Ovariano/enzimologia , Folículo Ovariano/metabolismo , Ovário/metabolismo , Filogenia , RNA Mensageiro/química , Alinhamento de Sequência/veterinária , Homologia de Sequência , Espermina Sintase/química , Espermina Sintase/genética , Baço/enzimologia , Baço/metabolismo
14.
Environ Sci Pollut Res Int ; 24(25): 20261-20272, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28702913

RESUMO

Although the growths of ambient pollutants have been attracting public concern, the characteristic of the associations between air pollutants and mortality remains elusive. Time series analysis with a generalized additive model was performed to estimate the associations between ambient air pollutants and mortality outcomes in Shenzhen City for the period of 2012-2014. The results showed that nitrogen dioxide (NO2)-induced excess risks (ER) of total non-accidental mortality and cardiovascular mortality were significantly increased (6.05% (95% CI 3.38%, 8.78%); 6.88% (95% CI 2.98%, 10.93%), respectively) in interquartile range (IQR) increase analysis. Also, these associations were strengthened after adjusting for other pollutants. Moreover, similar associations were estimated for sulfur dioxide (SO2), particulate matter with an aerodynamic diameter of <10 µm (PM10), and total non-accidental mortality. There were significant higher ERs of associations between PM10 and mortality for men than women; while there were significant higher ERs of associations between PM10/NO2 and mortality for elders (65 or elder) than youngers (64 or younger). Season analyses showed that associations between NO2 and total non-accidental mortality were more pronounced in hot seasons than in warm seasons. Taken together, NO2 was positively associated with total non-accidental mortality and cardiovascular mortality in Shenzhen even when the concentrations were below the ambient air quality standard. Policy measures should aim at reducing residents' exposure to anthropogenic NO2 emissions.


Assuntos
Poluentes Atmosféricos/toxicidade , Poluição do Ar/efeitos adversos , Monitoramento Ambiental , Mortalidade , Poluentes Atmosféricos/análise , Poluição do Ar/análise , China , Estudos Epidemiológicos , Feminino , Humanos , Masculino , Dióxido de Nitrogênio/análise , Dióxido de Nitrogênio/toxicidade , Material Particulado/análise , Material Particulado/toxicidade , Fatores de Risco , Dióxido de Enxofre/análise , Dióxido de Enxofre/toxicidade
15.
Plant Genome ; 10(2)2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28724072

RESUMO

Tar spot complex (TSC) is one of the most destructive foliar diseases of maize ( L.) in tropical and subtropical areas of Central and South America, causing significant grain yield losses when weather conditions are conducive. To dissect the genetic architecture of TSC resistance in maize, association mapping, in conjunction with linkage mapping, was conducted on an association-mapping panel and three biparental doubled-haploid (DH) populations using genotyping-by-sequencing (GBS) single-nucleotide polymorphisms (SNPs). Association mapping revealed four quantitative trait loci (QTL) on chromosome 2, 3, 7, and 8. All the QTL, except for the one on chromosome 3, were further validated by linkage mapping in different genetic backgrounds. Additional QTL were identified by linkage mapping alone. A major QTL located on bin 8.03 was consistently detected with the largest phenotypic explained variation: 13% in association-mapping analysis and 13.18 to 43.31% in linkage-mapping analysis. These results indicated that TSC resistance in maize was controlled by a major QTL located on bin 8.03 and several minor QTL with smaller effects on other chromosomes. Genomic prediction results showed moderate-to-high prediction accuracies in different populations using various training population sizes and marker densities. Prediction accuracy of TSC resistance was >0.50 when half of the population was included into the training set and 500 to 1,000 SNPs were used for prediction. Information obtained from this study can be used for developing functional molecular markers for marker-assisted selection (MAS) and for implementing genomic selection (GS) to improve TSC resistance in tropical maize.


Assuntos
Genoma de Planta , Genótipo , Doenças das Plantas/genética , Polimorfismo de Nucleotídeo Único , Zea mays/genética , Mapeamento Cromossômico/métodos , Genes de Plantas , Doenças das Plantas/microbiologia , Locos de Características Quantitativas
16.
Mar Pollut Bull ; 124(1): 292-302, 2017 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-28751027

RESUMO

The size and settling velocity of oil-mineral aggregates (OMAs) derived from diluted bitumen are primary constituents in predictive models for evaluating the potential fate of oil spilled in the aquatic environment. A series of low sediment concentration (15mg·L-1), colder water (<10°C) wave tank experiments designed to measure variability in these parameters in naturally-formed OMAs in response the presence or absence of chemical dispersant are discussed. Corresponding lab experiments revealed settling velocities of artificially formed OMAs on the order of 0.1-0.4mm·s-1. High-resolution imagery of settling particles were analyzed for particle size, density and settling velocity. In situ formation of OMAs in the wave tank was unsuccessful. Possible effects of chemical dispersant on natural sediment flocculation, the size of suspended oil droplets and clearance rates of suspended particles are discussed.


Assuntos
Hidrocarbonetos/análise , Minerais/análise , Poluição por Petróleo/análise , Poluentes Químicos da Água/análise , Floculação , Sedimentos Geológicos/química , Tamanho da Partícula
17.
Biosci Trends ; 11(3): 292-296, 2017 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-28484187

RESUMO

Influenza, a disease caused by a respiratory virus, sickened over 5,043,127 citizens in Shenzhen, China, from January 2014 to April 2016. An accurate forecasting of outbreaks of influenza-like illness (ILI, here we refer to ILI as the upper respiratory infection) could facilitate public health officials to suggest public health actions earlier. In this study, a random forest regression constructed with a one-year period of factors was adopted to forecast the weekly ILI rate using the clinical data from Shenzhen Health Information Center. The following conclusions were drawn based on this method: i) Compared to the predication with 52 (one-year) history observations, the accuracy of the predication was improved by adding another 52 first-order difference variables: mean absolute percentage error (MAPE) decreased from 5.04% to 4.35% and mean squared error (MSE) decreased from 2.85E-04 to 1.97E-04. ii) The variables with the first-order difference seemed more significant than the original history observations during the predication. In addition, both the recent observations and the later observations seemed important in the predicating procedure. iii) Analysis using the Pearson correlation concluded that weather conditions, the influence of which could have been implied by history observations and seemed insignificant for the predication, showed correlation to the weekly average temperature and maximum temperature. The correlation coefficients were -0.3656 and -0.3583, respectively.


Assuntos
Influenza Humana/epidemiologia , Temperatura , Tempo (Meteorologia) , China/epidemiologia , Humanos , Análise de Regressão
18.
Mar Pollut Bull ; 114(1): 176-182, 2017 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-27609234

RESUMO

Raindrops falling on the sea surface produce turbulence. The present study examined the influence of rain-induced turbulence on oil droplet size and dispersion of oil spills in Douglas Channel in British Columbia, Canada using hourly atmospheric data in 2011-2013. We examined three types of oils: a light oil (Cold Lake Diluent - CLD), and two heavy oils (Cold Lake Blend - CLB and Access Western Blend - AWB). We found that the turbulent energy dissipation rate produced by rainfalls is comparable to what is produced by wind-induced wave breaking in our study area. With the use of chemical dispersants, our results indicate that a heavy rainfall (rain rate>20mmh-1) can produce the maximum droplet size of 300µm for light oil and 1000µm for heavy oils, and it can disperse the light oil with fraction of 22-45% and the heavy oils of 8-13%, respectively. Heavy rainfalls could be a factor for the fate of oil spills in Douglas Channel, especially for a spill of light oil and the use of chemical dispersants.


Assuntos
Modelos Químicos , Poluição por Petróleo/análise , Petróleo/análise , Chuva , Poluentes Químicos da Água/análise , Colúmbia Britânica , Vento
19.
Sensors (Basel) ; 16(9)2016 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-27589766

RESUMO

Aimed at solving the misplaced body trajectory problem caused by the rolling of semi-round rigid feet when a robot is walking, a legged kinematic trajectory correction methodology based on the Least Squares Support Vector Machine (LS-SVM) is proposed. The concept of ideal foothold is put forward for the three-dimensional kinematic model modification of a robot leg, and the deviation value between the ideal foothold and real foothold is analyzed. The forward/inverse kinematic solutions between the ideal foothold and joint angular vectors are formulated and the problem of direct/inverse kinematic nonlinear mapping is solved by using the LS-SVM. Compared with the previous approximation method, this correction methodology has better accuracy and faster calculation speed with regards to inverse kinematics solutions. Experiments on a leg platform and a hexapod walking robot are conducted with multi-sensors for the analysis of foot tip trajectory, base joint vibration, contact force impact, direction deviation, and power consumption, respectively. The comparative analysis shows that the trajectory correction methodology can effectively correct the joint trajectory, thus eliminating the contact force influence of semi-round rigid feet, significantly improving the locomotion of the walking robot and reducing the total power consumption of the system.

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