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1.
J Hazard Mater ; 464: 132895, 2024 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-37976856

RESUMO

The extensive production and use of phthalates means that these compounds are now ubiquitous in the environment and various biota, which raises concerns about potential harmful health effects. In this study, phthalate metabolites (mPAEs) were measured in breast milk (n = 100) collected from mothers of southern China between 2014 - 2022. Of the nine target mPAEs, five were detected in all of the samples, including mono-methyl phthalate (MMP), mono-ethyl phthalate (MEP), mono-isobutyl phthalate (MiBP), mono-n-butyl phthalate (MnBP), and mono-(2-ethylhexyl) phthalate (MEHP). The total levels of mPAEs in breast milk ranged from 4.76 to 51.6 ng/mL, with MiBP and MnBP being the predominant isomers (MiBP + MnBP > 48.3%). Increasing trends were observed in MMP (5.7%/year) and MEHP (7.1%/year) levels during the study period, while a decreasing trend were observed in MiBP (-6.6%/year); no clear temporal trends were found for the other metabolites and total mPAE levels. The results indicate that exposure to phthalates is still prevalent in southern China. Breastfeeding was found to contribute to estimated daily phthalate intakes of 0.383-6.95 µg/kg-bw/day, suggesting insignificant health risks to infants based on dietary exposure. However, the increasing exposure to MMP and MEHP calls for more research into the possible sources and potential risks.


Assuntos
Poluentes Ambientais , Ácidos Ftálicos , Feminino , Lactente , Humanos , Leite Humano/química , Exposição Ambiental/análise , Poluentes Ambientais/metabolismo , Ácidos Ftálicos/análise , Medição de Risco , China
2.
Front Public Health ; 10: 1022666, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36299754

RESUMO

Spatial equality of parks is a significant issue in environmental justice studies. In cities with high-density development and limited land resources, this study uses a supply-demand adjusted two-step floating catchment area model (2SFCA), paying attention to residents' subjective preferences and psychological accessibility. It assesses equality of access to urban parks from two dimensions: spatial equality and quantitative equality at a fine scale of 100 × 100 m grid resolution. The spatial equality of urban parks in Chengdu is measured under different transportation modes (walking, cycling, and driving) based on multi-source geospatial big data and machine learning approaches. The results show: (1) There were significant differences in the spatial distribution of park accessibility under different modes of transportation. The spatial distribution under walking was significantly influenced by the park itself, while the distribution of rivers significantly influenced the spatial distribution under cycling and driving; (2) Accessibility to urban parks was almost universally equal in terms of driving, relatively equal in terms of cycling, and seriously unequal in terms of walking; (3) Spatial local autocorrelation analysis shows that park accessibility tended to be significantly clustered, with little spatial variation; and (4) The supply and demand of urban parks were relatively equal. The results can help urban planners to formulate effective strategies to alleviate spatial inequality more reasonably and precisely. The applied research methods can further improve the system of scientific evaluation from a new perspective.


Assuntos
Análise de Dados , Parques Recreativos , Big Data , Cidades , Análise Espacial
3.
Sci Rep ; 12(1): 10066, 2022 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-35710687

RESUMO

The northern fringe area of the East Asian summer monsoon (EASM) between arid and semiarid regions is a fragile eco-environment zone and ecological transition zone, and it is highly sensitive to climate change. Predicting the future migration of the northern boundary of the EASM is important for understanding future East Asian climate change and formulating of decisions on ecological protection and economic development in arid and semiarid regions. The reanalysis dataset and simulations of 23 models from the Coupled Models Intercomparison Project Phase 6 (CMIP6) were used to investigate the response of the boundary of the ESAM to the global warming. The multi-model ensemble showed a northwestward migration of the EASM northern boundary during the near-term (2020-2060) and late-term (2061-2099) of the twenty-first century under various Shared Socioeconomic Pathways (SSPs). The northern boundary migrated northwestward by 23-28 and 74-76 km in the near-term and late-term respectively, under SSP1-2.6, 2-4.5 and 3-7.0 and by ~ 44 km and ~ 107 km respectively during the near-term and late-term under SSP5-8.5. During the twenty-first century, under various SSPs, the surface of the East Asian subcontinent warmed more than the ocean, thereby increasing the contrast of near-surface temperature and sea level pressure in summer between the East Asian subcontinent and the surrounding oceans. In turn, the intensified land-sea thermal contrast reinforced the EASM meridional circulation and thus transported more moisture from the Indian Ocean into northern China. Additionally, a poleward migration and weakening of the East Asian subtropical westerly jet would also favor an increase in precipitation, eventually caused a northwestward migration of the EASM northern boundary. The results suggest that the arid and semiarid ecotone will become wetter, which could dramatically improve the eco-environment in the future.


Assuntos
Mudança Climática , Tempestades Ciclônicas , Aquecimento Global , Oceano Índico , Estações do Ano
4.
Sci Total Environ ; 830: 154820, 2022 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-35341846

RESUMO

Utilization of renewable energy has become a current energy development trend. In this study, the water footprints of a fuel cell electric vehicle (FCEV) and a compressed natural gas vehicle (CNG) under different fuel scenarios were evaluated. The FCEV exhibits a low water footprint of 27.2 L/100 km under steam methane reforming hydrogen production technology. Hydrogen production using steam methane reforming and water electrolysis via wind can enable the FCEV industry to save more water resources. The percentage difference between different metallic materials in automobiles was analyzed. The water consumption by steel accounted for 73.6% and 80.5%, respectively. The fluctuation law of the water footprint was analyzed based on different power structures and steel water consumption coefficients. It was found that for low steel water consumption coefficient, wind power generation is conducive to slowing down the water consumption during the entire life cycle. In addition, a sensitivity analysis was performed for the FCEV and CNG under different fuel scenarios. Fuel technology and material structure have a significant impact on the total water footprint. The results of this study can provide guidance for the layout of the automobile industry and for water-saving measures in the future.


Assuntos
Gás Natural , Emissões de Veículos , Hidrogênio/análise , Metano/análise , Veículos Automotores , Gás Natural/análise , Vapor/análise , Aço/análise , Emissões de Veículos/análise , Água/análise
5.
Medicine (Baltimore) ; 100(4): e24057, 2021 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-33530200

RESUMO

ABSTRACT: Health literacy (HL) has become an important public health issue and received growing attention in recent years. However, knowledge about the HL of adolescents and young adults is limited.[1] This study aimed to investigate the awareness rate of HL and its related factors among college freshmen in Jiangsu, China. And the results were used to support the promotion intervention to improve the HL of at-risk groups among this population.A total of 25,272 freshmen were surveyed through multi-stage stratified random sampling from 20 colleges and universities in Jiangsu province between 2016 to 2018. Data were obtained using the "Chinese Citizen Health Literacy Questionnaire" (2013 edition). Multiple logistic regression analysis was conducted to determine the factors influencing HL levels.The awareness rate of HL of college freshmen in Jiangsu province was 26.6% among the 25,272 subjects. The awareness rate of HL tended to increase from 2016 to 2018, which was 17.9%, 21.5%, and 39.6%, respectively (P < 0.001). Specifically, except for chronic diseases, knowledge and attitudes, knowledge and attitudes toward health-related behavior and lifestyle, health-related skill and scientific views of health, infection diseases, safety and first aid, medical care, health information awareness rate all have improved to a certain degree (P < .001). The independent factors associated with HL awareness rate were sex (odds ratio [OR] = 1.099, (1.039 -1.164)), residence (urban: OR = 1.141, (1.056∼1.234)), educational system (OR = 2.133, (1.975-2.305)), only child or not (OR = 1.087, (1.018-1.161)), family structure (OR = 1.192, (1.078-1.319)) and maternal education level (high school: OR = 1.183 (1.067-1.313); university and more: OR = 1.481 (1.324-1.658)).Awareness rate of HL of college freshmen is associated with multi-complex factors, further works are recommended to improve the HL levels of college freshmen, especially for the aspect of chronic diseases.


Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Letramento em Saúde/estatística & dados numéricos , Adolescente , China , Feminino , Estilo de Vida Saudável , Humanos , Modelos Logísticos , Estudos Longitudinais , Masculino , Características de Residência , Fatores de Risco , Fatores Socioeconômicos , Universidades , Adulto Jovem
6.
J Magn Reson Imaging ; 52(6): 1668-1678, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32445618

RESUMO

BACKGROUND: The noninvasive assessment of hepatic inflammatory activity (HIA) is crucial for making clinical decisions and monitoring therapeutic efficacy in chronic liver disease (CLD). PURPOSE: To develop MRI-based radiomics models by extracting features from the whole liver and localized regions of the right liver lobe, compare the efficiency of two radiomics models, and further develop a radiomics nomogram for the assessment of HIA in CLD. STUDY TYPE: Retrospective. POPULATION: In all, 137 consecutive patients. FIELD STRENGTH/SEQUENCE: 1.5T/T2 -weighted imaging. ASSESSMENT: All patients (nonsignificant HIA, n = 98; significant HIA, n = 39) were randomly divided into a training (n = 95) and a test cohort (n = 42). Radiomics features were extracted from the regions covering the whole liver (ROI-w) and localized regions of the right liver lobe (ROI-r). Least absolute shrinkage and selection operator (LASSO) and multivariate logistic regression analyses were used to select features and develop radiomics models. A combined model fusing the valuable radiomics features with clinical-radiological predictors was developed. Finally, a radiomics nomogram derived from the combined model was developed. STATISTICAL TESTS: Synthetic minority oversampling technique algorithm, LASSO, receiver operator characteristic curve, and calibration curve analysis were performed. RESULTS: The area under the curve (AUC), sensitivity, and specificity of the ROI-w radiomics model in assessing HIA were 0.858, 0.800, and 0.733, respectively. The ROI-r model were 0.844, 0.733, and 0.867, respectively. No differences were detected between the two radiomics models (P = 0.8329). The combined model fusing valuable ROI-w radiomics features, albumin, and periportal edema exhibited a promising performance (AUC, 0.911). The calibration curves showed good agreement between the actual observations and nomogram predictions. DATA CONCLUSION: The MRI-based radiomics models had a powerful ability to evaluate HIA and the ROI-w radiomics model was comparable to the ROI-r model. Moreover, the radiomics nomogram could be a favorable method to individually estimate HIA in CLD. J. MAGN. RESON. IMAGING 2020;52:1668-1678.


Assuntos
Hepatopatias , Imageamento por Ressonância Magnética , Humanos , Hepatopatias/diagnóstico por imagem , Nomogramas , Estudos Retrospectivos
7.
Breast J ; 26(7): 1284-1288, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32291841

RESUMO

The purpose of this study was to identify a correlation between the screening BI-RADS 0 (recall) rates and diagnostic BI-RADS 3 (short-interval follow-up) rates of individual interpreting radiologists, with the goal of utilizing the BI-RADS 3 rate as an acceptable performance metric in the diagnostic population. A multicenter retrospective analysis of medical audit statistics was conducted on annual radiologist performance data collected over a 14-year period in a community hospital-based practice. Mixed regression models were used to estimate the association between screening BI-RADS 0 and diagnostic BI-RADS 3 examinations while adjusting for calendar year, annual radiologist screening volume, annual radiologist diagnostic volume, and diagnostic examination indication. A moderate statistically significant positive correlation was established between the screening BI-RADS 0 rates and Diagnostic BI-RADS 3 rates (Pearson correlation coefficient + 0.349, P ≤ .001). Furthermore, when utilizing a national benchmark range of 8%-12% as an acceptable BI-RADS 0 rate within a screening population, the correlative BI-RADS 3 assessment rate was demonstrated to be approximately 16%. We propose that this BI-RADS category 3 rate may represent an additional acceptable performance metric in the diagnostic population. Routine inclusion of an interpreting mammographer's diagnostic BI-RADS 3 rate in the annual medical audit may help reduce inappropriate and/or excess use of the BI-RADS 3 category, which may lead to significant potential reductions in follow-up examinations with their associated healthcare-related costs, resource expenditure, and induced patient anxiety.


Assuntos
Benchmarking , Neoplasias da Mama , Neoplasias da Mama/diagnóstico por imagem , Feminino , Seguimentos , Humanos , Mamografia , Estudos Retrospectivos
8.
Sci Rep ; 9(1): 14393, 2019 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-31591457

RESUMO

Drought disaster space agglomeration assessment is one of the important components of meteorological disaster prevention and mitigation. Agriculture affected by drought disaster is not only a serious threat to world food security, but also an obstacle to sustainable development. Additionally, China is an important agricultural import and export country in the world. Therefore, we used the global Moran's I and the local indicators of spatial autocorrelation (LISA) to reveal the spatial agglomeration of agricultural drought disaster in China from1978 to 2016, respectively. The results showed that China's agricultural drought disaster presents local spatial autocorrelation of geographical agglomeration at national level during the study period. The spatial agglomeration regions of China's agricultural drought disaster were in Inner Mongolia, Jilin province, Heilongjiang province, Liaoning province, Shanxi province, Hebei province, Shandong province, Shaanxi province and Henan province, indicating that agricultural drought disaster mainly distributed in North and Northwest China, especially occurred in the Yellow River Basin and its north areas. We also found that the overall movement direction of agricultural drought disaster agglomeration regions was northwest, and the maximum moving distance was 722.16 km. Our results might provide insight in early warning and prevention for drought disaster.

9.
Sensors (Basel) ; 19(11)2019 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-31159245

RESUMO

With the launch of BDS-3 and Galileo new satellites, the BeiDou navigation satellite system (BDS) has developed from the regional to global system, and the Galileo constellation will consist of 26 satellites in space. Thus, BDS, GPS, GLONASS, and Galileo all have the capability of global positioning services. It is meaningful to evaluate the ability of global precise point positioning (PPP) of the GPS, BDS, GLONASS, and Galileo. This paper mainly contributes to the assessment of BDS-2, BDS-2/BDS-3, GPS, GLONASS, and Galileo PPP with the observations that were provided by the international Global Navigation Satellite System (GNSS) Monitoring and Assessment System (iGMAS). The Position Dilution of Precision (PDOP) value was utilized to research the global coverage of GPS, BDS-2, BDS-2/BDS-3, GLONASS, and Galileo. In particular, GPS-only, BDS-2-only, BDS-2/BDS-3, GLONASS-only, Galileo-only, and multi-GNSS combined PPP solutions were analyzed to verify the capacity of the PPP performances in terms of positioning accuracy, convergence time, and zenith troposphere delay (ZTD) accuracy. In view of PDOP, the current BDS and Galileo are capable of global coverage. The BDS-2/BDS-3 and Galileo PDOP values are fairly evenly distributed around the world similar to GPS and GLONASS. The root mean square (RMS) of positioning errors for static BDS-2/BDS-3 PPP and Galileo-only PPP are 10.7, 19.5, 20.4 mm, and 6.9, 18.6, 19.6 mm, respectively, in the geographic area of the selected station, which is the same level as GPS and GLONASS. It is worth mentioning that, by adding BDS-3 observations, the positioning accuracy of static BDS PPP is improved by 17.05%, 24.42%, and 35.65%, and the convergence time is reduced by 27.15%, 27.87%, and 35.76% in three coordinate components, respectively. Similar to the static positioning, GPS, BDS-2/BDS-3, GLONASS, and Galileo have the basically same kinematic positioning accuracy. Multi-GNSS PPP significantly improves the positioning performances in both static and kinematic positioning. In terms of ZTD accuracy, the difference between GPS, BDS-2/BDS-3, GLONASS, and Galileo is less than 1 mm, and the BDS-2/BDS-3 improves ZTD accuracy by 20.48% over the BDS-2. The assessment of GPS, BDS-2, BDS-2/BDS-3, GLONASS, Galileo, and multi-GNSS global PPP performance are shown to make comments for the development of multi-GNSS integration, global precise positioning, and the construction of iGMAS.

10.
Genet Med ; 20(8): 817-824, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29120459

RESUMO

PURPOSE: Noninvasive prenatal screening (NIPS) sequences a mixture of the maternal and fetal cell-free DNA. Fetal trisomy can be detected by examining chromosomal dosages estimated from sequencing reads. The traditional method uses the Z-test, which compares a subject against a set of euploid controls, where the information of fetal fraction is not fully utilized. Here we present a Bayesian method that leverages informative priors on the fetal fraction. METHOD: Our Bayesian method combines the Z-test likelihood and informative priors of the fetal fraction, which are learned from the sex chromosomes, to compute Bayes factors. Bayesian framework can account for nongenetic risk factors through the prior odds, and our method can report individual positive/negative predictive values. RESULTS: Our Bayesian method has more power than the Z-test method. We analyzed 3,405 NIPS samples and spotted at least 9 (of 51) possible Z-test false positives. CONCLUSION: Bayesian NIPS is more powerful than the Z-test method, is able to account for nongenetic risk factors through prior odds, and can report individual positive/negative predictive values.


Assuntos
Teorema de Bayes , Diagnóstico Pré-Natal/métodos , Análise de Sequência de DNA/métodos , Adulto , China , Feminino , Feto , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Cadeias de Markov , Gravidez , Cuidado Pré-Natal
11.
Psychiatry Res ; 253: 22-27, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28319788

RESUMO

This study aimed to clarify the relationship between functional and dysfunctional impulsivity and attempted suicide in rural China. Data of this study came from the investigation of 407 suicide attempters and their paired non-suicide attempters matched with the same gender, age (±3 years) and residence area in six counties in rural Shandong, China. Suicide attempters accounted for a lower proportion on high functional impulsivity, but a higher proportion on high dysfunctional impulsivity than non-suicide attempters. Dysfunctional impulsivity in the male denoted a significant risk factor for attempted suicide, even after adjustment for psychiatric disorder and demographic factors. Suicide attempters with high dysfunctional impulsivity had a higher percent of family suicide history than those with low dysfunctional impulsivity. High functional impulsivity was a significant protective factor for attempted suicide in the group aged 35-59 years, but a significant risk factor in the group aged 15-34 years. Suicide attempters with low functional impulsivity had poorer economic status and older age than those with high functional impulsivity. Our findings support the key roles of functional and dysfunctional impulsivity in attempted suicide among rural residents of China.


Assuntos
Comportamento Impulsivo , Tentativa de Suicídio/psicologia , Adolescente , Adulto , Estudos de Casos e Controles , China , Demografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Proteção , Fatores de Risco , População Rural/estatística & dados numéricos , Fatores Socioeconômicos , Adulto Jovem
12.
Biomed Eng Online ; 13: 148, 2014 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-25361700

RESUMO

BACKGROUND: There is a high probability of accidental perforation of the vertebral pedicle wall in pedicle screw insertion surgery. A pedicle screw (PS) measurement device with an optical probe has been reported to send out a warning signal before the PS tip breaking the vertebral pedicle wall. METHODS: In this study, we explored the detection depth of optical probe in this measurement device, which was closely related to the effective alarm distance. In the boundary, the vertebrae tissues could be treated as 2-layer models including spongy bones and compact bones. The Monte Carlo simulation and phantom models were performed to analyse and define the detection depth. Then the porcine vertebrae models were performed to obtain optical spectrum and reduced scattering coefficient, based on which the detection depths were deduced. Moreover, a comparison was made to explore the most significant pattern factor from the experiment results. RESULTS: According to the pattern factor, an alarm threshold was successfully deduced to define the alarm distance during pedicle screw monitoring. CONCLUSIONS: Thus, the proposed alarm standard based on detection depth provides a potential for guiding pedicle screw in surgery.


Assuntos
Parafusos Pediculares , Algoritmos , Animais , Osso e Ossos/anatomia & histologia , Simulação por Computador , Desenho de Equipamento , Vértebras Lombares/anatomia & histologia , Método de Monte Carlo , Óptica e Fotônica , Imagens de Fantasmas , Probabilidade , Espalhamento de Radiação , Espectroscopia de Luz Próxima ao Infravermelho , Suínos , Tomografia Computadorizada por Raios X
13.
J Asthma ; 50(7): 729-36, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23745594

RESUMO

OBJECTIVES: Home-based, multifaceted interventions have been effective in reducing asthma morbidity in children. However, identification of independent components that contribute to outcomes and delineating effectiveness by level of asthma symptoms would help to refine the intervention and target appropriate populations. METHODS: A community health educator led asthma intervention implemented in a low-income African-American neighborhood included asthma management education, individually tailored low-cost asthma home trigger remediation, and referrals to social and medical agencies, when appropriate. Changes in asthma morbidity measures were assessed in relation to implementation of individual intervention components using multivariable logistic regression. RESULTS: Among the 218 children who completed the year-long program, there were significant reductions in measures of asthma morbidity, including symptoms, urgent care visits, emergency department (ED) visits, hospitalizations, missed school days, and missed work days for caretakers. We also found significant decreases in the prevalence of many home asthma triggers and improvements in asthma management practices. Improvement in caretaker's ability to manage the child's asthma was associated with reduction in ED visits for asthma and uncontrolled asthma. Specific home interventions, such as repair of water leaks and reduced exposure to plants, dust, clutter and stuffed toys, may be related to reduction in asthma morbidity. CONCLUSIONS: This program was effective in reducing asthma morbidity in low-income African-American children and identified specific interventions as possible areas to target in future projects. Furthermore, the intervention was useful in children with persistent asthma symptoms as well as those with less frequent asthma exacerbations.


Assuntos
Asma/fisiopatologia , Asma/terapia , Educação de Pacientes como Assunto/métodos , Adolescente , Negro ou Afro-Americano , Antiasmáticos/administração & dosagem , Antiasmáticos/uso terapêutico , Asma/economia , Asma/etnologia , Chicago , Criança , Pré-Escolar , Gerenciamento Clínico , Habitação , Humanos , Lactente , Modelos Logísticos , Análise Multivariada , Educação de Pacientes como Assunto/normas , Pobreza
14.
Environ Sci Technol ; 47(1): 95-101, 2013 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-22747244

RESUMO

Effects of oxygen-containing surface functionalities on the adsorption of mixtures including CO(2)/CH(4), CO(2)/N(2), and CO(2)/H(2)O have been investigated in the current work. Together with Bader charge analysis, electronic structure calculations have provided the initial framework comprising both the geometry and corresponding charge information required to carry out statistical-based molecular simulations. The adsorption isotherms and selectivity of CO(2) from CO(2)/N(2), CO(2)/CH(4), and CO(2)/H(2)O gas mixtures were determined by grand canonical Monte Carlo simulations at temperature/pressure conditions relevant to carbon capture and sequestration applications. The interactions between the surfaces with induced polarity and nonpolar/polar molecules have been investigated. It has been observed that, due to the induced polarity of the surface functionalization, the selectivity of CO(2) over CH(4) increases from approximately 2 to higher than 5, and the selectivity of CO(2) over N(2) increases from approximately 5 to 20, especially in the low-pressure regime. However, water vapor will always preferentially adsorb over CO(2) in carbon-based systems containing oxygen functionalized surfaces at conditions relevant to carbon capture application. Molecular simulation results indicate that the surface chemistry in micropores is tunable thereby influencing the selectivity for enhanced uptake of CO(2).


Assuntos
Poluentes Atmosféricos/química , Dióxido de Carbono/química , Sequestro de Carbono , Modelos Moleculares , Adsorção , Simulação por Computador , Grafite/química , Metano/química , Método de Monte Carlo , Nitrogênio/química , Porosidade
15.
Environ Sci Technol ; 46(3): 1940-7, 2012 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-22216997

RESUMO

Carbon capture combined with utilization and storage has the potential to serve as a near-term option for CO(2) emissions reduction. CO(2) capture by carbon-based sorbents and CO(2) storage in geologic formations such as coal and shale both require a thorough understanding of the CO(2) adsorption properties in microporous carbon-based materials. Complex pore structures for natural organic materials, such as coal and gas shale, in addition to general carbon-based porous materials are modeled as a collection of independent, noninterconnected, functionalized graphitic slit pores with surface heterogeneities. Electronic structure calculations coupled with van der Waals-inclusive corrections have been performed to investigate the electronic properties of functionalized graphitic surfaces. With Bader charge analysis, electronic structure calculations can provide the initial framework comprising both the geometry and corresponding charge information required to carry out statistical modeling. Grand canonical Monte Carlo simulations were carried out to determine the adsorption isotherms for a given adsorbent-adsorbate interaction at temperature/pressure conditions relevant to carbon capture applications to focus on the effect of the surface functionalities. On the basis of the current work, oxygen-containing functional groups were predicted to enhance CO(2) adsorption in microporous carbon materials in the absence of water vapor, and the hydrated graphite was found to hinder CO(2) adsorption.


Assuntos
Dióxido de Carbono/química , Sequestro de Carbono , Grafite/química , Modelos Químicos , Conformação Molecular , Oxigênio/química , Adsorção , Simulação por Computador , Estrutura Molecular , Método de Monte Carlo , Porosidade , Pressão , Eletricidade Estática , Temperatura
16.
Stress Health ; 28(4): 340-6, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22190389

RESUMO

In a sample of 368 Chinese high school students, the present study examined the different effects of Chinese high school students' academic stress on their depressive symptoms and the moderating effects of gender and students' perceptions of school climate on the relationships between their academic stress and depressive symptoms. Regression mixture model identified two different kinds of subgroups in the effects of students' academic stress on their depressive symptoms. One subgroup contained 90% of the students. In this subgroup, the students' perceptions of academic stress from lack of achievement positively predicted their depressive symptoms. For the other 10% of the students, academic stress did not significantly predict their depressive symptoms. Next, multinomial regression analysis revealed that girls or students who had high levels of achievement orientation were more likely to be in the first subgroup. The findings suggested that gender and students' perceptions of school climate could moderate the relationships between Chinese high school students' academic stress and their depressive symptoms.


Assuntos
Logro , Depressão/psicologia , Instituições Acadêmicas , Meio Social , Estresse Psicológico/psicologia , Adolescente , Povo Asiático/psicologia , China , Escolaridade , Feminino , Humanos , Masculino , Fatores Sexuais
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