Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 19 de 19
Filtrar
Mais filtros

Bases de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Huan Jing Ke Xue ; 43(11): 5326-5332, 2022 Nov 08.
Artigo em Chinês | MEDLINE | ID: mdl-36437104

RESUMO

Plastic pollution is a global concern and an issue in environmental governance. Based on the updated "Plastic Prohibition/Restriction Order" issued recently in China, the present study systematically reviewed the implementation effectiveness of the "Plastic Prohibition/Restriction Order" since 2007. Furthermore, we summarized plastics in China and plastic waste management progress policies. Additionally, three deficiencies of the updated "Plastic Prohibition/Restriction Order" were discussed:policy formulation, implementation, and supervision. Some positive recommendations were provided based on the available reports, such as integrating plastic pollution into national basic laws and regulation systems, building a network platform for public attendance, and coordinating the publicity of the "Plastic prohibition/Restriction Order" with the public interest. Besides these measurements, some points about plastic waste management in the future were also highlighted, such as the "blind area" in small retail stores, the rational sharing of environmental protection responsibility, new materials and processes, and recycling and disposal systems for plastic wastes. Most importantly, the present study could provide ideas for policy-makers to address plastic pollution at its sources.


Assuntos
Conservação dos Recursos Naturais , Plásticos , Política Ambiental , Formulação de Políticas , China
2.
Environ Conserv ; 49(2): 114-121, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36246571

RESUMO

Protected areas (PAs) are critical for achieving conservation, economic and development goals, but the factors that lead households to engage in prohibited resource collection in PAs are not well understood. We examine collection behaviours in community forests and the protected Chitwan National Park in Chitwan, Nepal. Our approach incorporates household and ecological data, including structured interviews, spatially explicit data on collection behaviours measured with computer tablets and a systematic field survey of invasive species. We pair our data with a framework that considers factors related to a household's demand for resources, barriers to prohibited resource collection, barriers to legal resource collection and alternatives to resource collection. The analysis identifies key drivers of prohibited collection, including sociodemographic variables and perceptions of an invasive plant (Mikania micrantha). The social-ecological systems approach reveals that household perceptions of the presence of M. micrantha were more strongly associated with resource collection decisions than the actual ecologically measured presence of the plant. We explore the policy implications of our findings for PAs and propose that employing a social-ecological systems approach leads to conservation policy and scientific insights that are not possible to achieve with social or ecological approaches alone.

3.
J Magn Reson ; 341: 107257, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35752065

RESUMO

Monte Carlo simulations and a mathematical model of spectral fitting were used to study the correlations between metabolites with overlapping resonances. The dependence of the polarity and the magnitude of cross-correlation coefficients between overlapping metabolites on the spectral patterns of MRS signals was investigated. The results demonstrate the importance of quantifying metabolite correlations originating from spectral overlap as they may confound determination of correlations of biological origin. The findings also indicate that it is possible to minimize unwanted metabolite correlations by altering spectral patterns in the presence of significant spectral overlap.


Assuntos
Modelos Teóricos , Simulação por Computador , Método de Monte Carlo
4.
Respir Med ; 186: 106524, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34265629

RESUMO

BACKGROUND: The 2021 Global Initiative for Asthma (GINA) report recommends as-needed inhaled corticosteroid (ICS)/formoterol irrespective of severity, and maintenance and reliever treatment (MART) from GINA Step 3 as part of Treatment Track 1, partly based on the SYGMA studies. We investigated how current clinical practice in Australia, Canada, China and the Philippines relates to latest GINA recommendations. METHODS: Patients and physicians were recruited from online panels between July and August 2020 and invited to complete an online survey. INCLUSION CRITERIA: age ≥18 years, current/past physician diagnosis of asthma (patients); primary care (Canada also included respirologists/respiratory therapists), treating ≥4 patients with asthma per month, ≥3 years in clinical practice (physicians). RESULTS: Overall, 1216/70,183 patients and 803/8376 physicians replied and were eligible for inclusion. Only 8-15% of patients were using MART; 66-81% used regular maintenance therapy with/without an as-needed reliever. Across the four countries, physicians classified 48-63% of their patients as mild (GINA Steps 1-2) and 28-36% as moderate (GINA Steps 3-4). Generally, physicians rated symptom control over exacerbation reduction as their main treatment goal; patients also ranked symptom relief as very important. Approximately 9-29% of patients and 24-45% of physicians were unaware of MART, and among those who prescribed MART, 80-95% prescribed an additional (non-ICS) as-needed reliever. INTERPRETATION: Most physicians prioritized managing asthma symptoms over exacerbations. A lack of awareness and understanding of MART dosing exists among physicians. Practical strategies are required to implement GINA recommendations effectively in real-world clinical practice and to identify appropriate patients for MART.


Assuntos
Corticosteroides/administração & dosagem , Asma/tratamento farmacológico , Efeitos Psicossociais da Doença , Fumarato de Formoterol/administração & dosagem , Quimioterapia de Manutenção/métodos , Médicos de Atenção Primária , Guias de Prática Clínica como Assunto , Adolescente , Adulto , Progressão da Doença , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Inquéritos e Questionários , Adulto Jovem
5.
World J Surg Oncol ; 18(1): 331, 2020 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-33308239

RESUMO

OBJECTIVES: To fully assess the quality of the guidelines for the management of malignant pleural effusions (MPE) and ascites and reveal the heterogeneity of recommendations and possible reasons among guidelines. METHODS: A systematic search was performed in the database to obtain guidelines for the management of MPE and ascites. The AGREE IIGtool was used to assess the quality of these guidelines. The Measurement Scale of Rate of Agreement (MSRA) was introduced to assess the scientific agreement of formulated recommendations for the management of MPE and ascites among guidelines, and evidence supporting these recommendations was extracted and analyzed. RESULTS: Nine guidelines were identified. Only 4 guidelines scored more than 60% and are worth recommending. Recommendations were also heterogeneous among guidelines for the management of MPE, and the main reasons were the different emphases of the recommendations for the treatment of MPE, the contradictions in recommendations, and the unreasonably cited evidence for MPE. CONCLUSIONS: The quality of the management guidelines for patients with MPE and malignant ascites was highly variable. Specific improvement of the factors leading to the heterogeneity of recommendations will be a reasonable and effective way for developers to upgrade the recommendations in the guidelines for MPE.


Assuntos
Derrame Pleural Maligno , Ascite/etiologia , Ascite/terapia , Humanos , Derrame Pleural Maligno/diagnóstico , Derrame Pleural Maligno/terapia , Prognóstico
6.
J Magn Reson ; 316: 106756, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32521478

RESUMO

A single-step spectral editing approach using an always-on editing pulse was proposed to enhance the signals of strongly coupled spins. Specifically, a single-step spectral editing sequence with an always-on editing pulse applied at 2.12 ppm was used to enhance glutamine (Gln) and glutathione (GSH) signals at TE = 56 ms on a 7 T scanner. Density matrix simulations demonstrated that the current method (TE = 56 ms) led to large signal enhancement of at least 61% for Gln and 51% for GSH compared to a previous single-step method (TE = 106 ms). Monte Carlo simulations showed that the current method reduced noise-originated variations by 31% for Gln and 26% for GSH compared to a previous three-step spectral editing method from which the present method was derived.


Assuntos
Química Encefálica , Glutamina/metabolismo , Glutationa/metabolismo , Espectroscopia de Ressonância Magnética/métodos , Adulto , Algoritmos , Feminino , Ácido Glutâmico/metabolismo , Humanos , Masculino , Método de Monte Carlo , Sensibilidade e Especificidade , Razão Sinal-Ruído
7.
Int Ophthalmol ; 40(7): 1831-1839, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32249376

RESUMO

PURPOSE: To evaluate the relationship between cataract types and subjective visual function among patients with age-related cataract. METHODS: This was a prospective, multicenter, 831 Chinese patient-based, cross-sectional study. Patients were administered the Visual Function Index-14 (VF-14) and the 25-item National Eye Institute Visual Functioning Questionnaire (NEI-VFQ-25) to evaluate their subjective visual function. Lens Opacities Classification System III (LOCS III) was used to evaluate the type of cataract. Relationships among these parameters were analyzed. RESULTS: LOCS III cortical (C) and posterior subcapsular scores are negatively associated with VF-14 (r = - 0.188, P < 0.01; r = - 0.146, P < 0.01) and total score of NEI-VFQ-25 (r = - 0.223, P < 0.01; r = - 0.160, P < 0.01), respectively; LOCS III nuclear opalescence (NO) score is positively associated with VF-14 (r = 0.087, P < 0.05) and total score of NEI-VFQ-25 (r = 0.097, P < 0.05). In multiple linear regression, a decrease in the LOCS III C score is a significant predictor for improvement of the total score of NEI-VFQ-25 (ß = - 1.286, P < 0.05). In contrast, an increase in LOCS III NO score is a significant predictor for improvement of VF-14 (ß = 3.826, P < 0.01) and total score of NEI-VFQ-25 (ß = 4.618, P < 0.01). Patients with LOCS III C score ≤ 2 have higher VF-14 (49.38 versus 43.74, P < 0.01), total (80.73 versus 71.58, P < 0.01) and subscale scores of NEI-VFQ-25 than patients with LOCS III C score > 2. CONCLUSION: Cortical cataract has adverse effects on subjective visual function, while mild-to-moderate nuclear cataract has positive effects. Furthermore, "LOCS III C score > 2" can be a potential cutoff as a reference for cataract surgery without self-assessing questionnaires.


Assuntos
Catarata , National Eye Institute (U.S.) , Fatores Etários , Idoso , Catarata/diagnóstico , Estudos Transversais , Feminino , Humanos , Masculino , Estudos Prospectivos , Qualidade de Vida , Inquéritos e Questionários , Estados Unidos , Acuidade Visual
8.
Lancet ; 394(10196): 407-418, 2019 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-31230828

RESUMO

BACKGROUND: Asthma is a common chronic airway disease worldwide. Despite its large population size, China has had no comprehensive study of the national prevalence, risk factors, and management of asthma. We therefore aimed to estimate the national prevalence of asthma in a representative sample of the Chinese population. METHODS: A representative sample of 57 779 adults aged 20 years or older was recruited for the national cross-sectional China Pulmonary Health (CPH) study using a multi-stage stratified sampling method with parameters derived from the 2010 census. Ten Chinese provinces, representative of all socioeconomic settings, from six geographical regions were selected, and all assessments were done in local health centres. Exclusion criteria were temporary residence, inability to take a spirometry test, hospital treatment of cardiovascular conditions or tuberculosis, and pregnancy and breastfeeding. Asthma was determined on the basis of a self-reported history of diagnosis by a physician or by wheezing symptoms in the preceding 12 months. All participants were assessed with a standard asthma questionnaire and were classed as having or not having airflow limitation through pulmonary function tests before and after the use of a bronchodilator (400 µg of salbutamol). Risk factors for asthma were examined by multivariable-adjusted analyses done in all participants for whom data on the variables of interest were available. Disease management was assessed by the self-reported history of physician diagnosis, treatments, and hospital visits in people with asthma. FINDINGS: Between June 22, 2012, and May 25, 2015, 57 779 participants were recruited into the CPH study. 50 991 (21 446 men and 29 545 women) completed the questionnaire survey and had reliable post-bronchodilator pulmonary function test results and were thus included in the final analysis. The overall prevalence of asthma in our sample was 4·2% (95% CI 3·1-5·6), representing 45·7 million Chinese adults. The prevalence of asthma with airflow limitation was 1·1% (0·9-1·4), representing 13·1 million adults. Cigarette smoking (odds ratio [OR] 1·89, 95% CI 1·26-2·84; p=0·004), allergic rhinitis (3·06, 2·26-4·15; p<0·0001), childhood pneumonia or bronchitis (2·43, 1·44-4·10; p=0·002), parental history of respiratory disease (1·44, 1·02-2·04; p=0·040), and low education attainment (p=0·045) were associated with prevalent asthma. In 2032 people with asthma, only 28·8% (95% CI 19·7-40·0) reported ever being diagnosed by a physician, 23·4% (13·9-36·6) had a previous pulmonary function test, and 5·6% (3·1-9·9) had been treated with inhaled corticosteroids. Furthermore, 15·5% (11·4-20·8) people with asthma reported at least one emergency room visit and 7·2% (4·9-10·5) at least one hospital admission due to exacerbation of respiratory symptoms within the preceding year. INTERPRETATION: Asthma is prevalent but largely undiagnosed and undertreated in China. It is crucial to increase the awareness of asthma and disseminate standardised treatment in clinical settings to reduce the disease burden. FUNDING: National Key R&D Program of China, Ministry of Science and Technology of China; the Special Research Foundation for Public Welfare of Health, Ministry of Health of China; the Chinese National Research Program for Key Issues in Air Pollution Control; and the National Natural Science Foundation of China.


Assuntos
Asma/tratamento farmacológico , Asma/epidemiologia , Bronquite/epidemiologia , Fumar Cigarros/epidemiologia , Pneumonia/epidemiologia , Rinite Alérgica/epidemiologia , Administração por Inalação , Corticosteroides/uso terapêutico , Adulto , Asma/etiologia , Bronquite/complicações , China/epidemiologia , Fumar Cigarros/efeitos adversos , Estudos Transversais , Gerenciamento Clínico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pneumonia/complicações , Prevalência , Rinite Alérgica/complicações , Fatores de Risco , Inquéritos e Questionários
9.
MAGMA ; 32(2): 237-246, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30467687

RESUMO

OBJECTIVES: This study sought to investigate the effects of carrier frequency mismatch on spectral editing and its correction by frequency matching of basis functions. MATERIALS AND METHODS: Full density matrix computations and Monte-Carlo simulations based on magnetic resonance spectroscopy (MRS) data collected from five healthy volunteers at 7 T were used to analyze the effects of carrier frequency mismatch on spectral editing. Relative errors in metabolite quantification were calculated with and without frequency matching of basis functions. The algorithm for numerical computation of basis functions was also improved for higher computational efficiency. RESULTS: We found significant errors without frequency matching of basis functions when carrier frequency mismatch was generally considered negligible. By matching basis functions with the history of frequency deviation, the mean errors in glutamate, glutamine, γ-aminobutyric acid, and glutathione concentrations were reduced from 3.90%, 1.85%, 11.53%, and 3.43% to 0.18%, 0.34%, 0.40%, and 0.51%, respectively. CONCLUSION: Matching basis functions to frequency deviation history was necessary even when frequency deviations during frequency-selective spectral editing were fairly small. Basis set frequency matching significantly improved accuracy in the quantification of glutamate, glutamine, γ-aminobutyric acid, and glutathione concentrations.


Assuntos
Espectroscopia de Ressonância Magnética/métodos , Algoritmos , Simulação por Computador , Ácido Glutâmico/metabolismo , Glutamina/metabolismo , Glutationa/metabolismo , Giro do Cíngulo/diagnóstico por imagem , Giro do Cíngulo/metabolismo , Voluntários Saudáveis , Humanos , Imageamento por Ressonância Magnética , Espectroscopia de Ressonância Magnética/estatística & dados numéricos , Método de Monte Carlo , Razão Sinal-Ruído , Ácido gama-Aminobutírico/metabolismo
10.
Biol Psychol ; 128: 125-131, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28757070

RESUMO

Studies testing the benefits of enriching smoking-cessation video ads with attention-grabbing sensory features have yielded variable results. Dopamine transporter gene (DAT1) has been implicated in attention deficits. We hypothesized that DAT1 polymorphism is partially responsible for this variability. Using functional magnetic resonance imaging, we examined brain responses to videos high or low in attention-grabbing features, indexed by "message sensation value" (MSV), in 53 smokers genotyped for DAT1. Compared to other smokers, 10/10 homozygotes showed greater neural response to High- vs. Low-MSV smoking-cessation videos in two a priori regions of interest: the right temporoparietal junction and the right ventrolateral prefrontal cortex. These regions are known to underlie stimulus-driven attentional processing. Exploratory analysis showed that the right temporoparietal response positively predicted follow-up smoking behavior indexed by urine cotinine. Our findings suggest that responses to attention-grabbing features in smoking-cessation messages is affected by the DAT1 genotype.


Assuntos
Atenção/fisiologia , Encéfalo/fisiologia , Proteínas da Membrana Plasmática de Transporte de Dopamina/genética , Abandono do Hábito de Fumar/psicologia , Fumar/genética , Adolescente , Adulto , Mapeamento Encefálico , Feminino , Marcadores Genéticos , Genótipo , Promoção da Saúde/métodos , Humanos , Individualidade , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Fumar/fisiopatologia , Abandono do Hábito de Fumar/métodos , Gravação em Vídeo , Adulto Jovem
11.
Magn Reson Med ; 78(6): 2072-2081, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28164364

RESUMO

PURPOSE: To simultaneously measure concentration and T1 and T2 values of metabolites in the human brain in a single scan session. METHODS: A new pulse sequence with multiple variable acquisition parameters was proposed to encode metabolite T1 and T2 information into the acquired data. A linear combination-fitting algorithm was developed in-house to simultaneously determine metabolite concentrations and relaxation times. RESULTS: Concentration, T1 , and T2 values of N-acetyl-aspartate, total creatine, total choline, and glutamate were reliably measured in the frontal gray matter and white matter regions of nine healthy volunteers at 7 tesla in less than 10 minutes of scan time per voxel. T1 and T2 values of glutamine, as well as T1 of glutathione, were also measured in the frontal gray matter region with reasonable precision. CONCLUSION: The proposed technique allows multiparametric characterization of brain metabolites in a single scan session, making it possible to measure both levels and intracellular microenvironments of brain chemicals in clinical MR spectroscopy studies. Magn Reson Med 78:2072-2081, 2017. © 2017 International Society for Magnetic Resonance in Medicine.


Assuntos
Encéfalo/diagnóstico por imagem , Processamento de Imagem Assistida por Computador , Espectroscopia de Ressonância Magnética , Adulto , Algoritmos , Ácido Aspártico/análogos & derivados , Ácido Aspártico/análise , Colina/análise , Creatina/análise , Feminino , Lobo Frontal/diagnóstico por imagem , Ácido Glutâmico/análise , Substância Cinzenta/diagnóstico por imagem , Voluntários Saudáveis , Humanos , Masculino , Método de Monte Carlo , Imagens de Fantasmas , Substância Branca/diagnóstico por imagem , Adulto Jovem
12.
Int J Ophthalmol ; 9(12): 1761-1765, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28003976

RESUMO

AIM: To investigate the effect of posterior scleral reinforcement (PSR) on circulation of pathologic myopia eyes with posterior staphyloma by optical coherence tomography angiography (OCTA). METHODS: The study included 30 pathologic myopia eyes with posterior staphyloma which underwent PSR (PSR group) for 6 to 18mo ago, and 30 age and myopia matched eyes without PSR surgery as control group. Macular, choriocapillaris and radial peripapillary capillary (RPC) flow density were measured by OCTA, and the measurements were compared between groups. RESULTS: OCTA found no significant differences in macular flow density between PSR and control groups. For the superficial flow, whole enface flow density (WED), fovea density (FD), and parafoveal density (PD) were 46.55%±5.19% vs 47.29%±4.12% (P=0.542), 31.45%±6.35% vs 31.17%±4.48% (P=0.841), and 48.82%±5.66% vs 49.21%±4.15% (P=0.756) in PSR and control groups, respectively. For the deep flow, WED, FD, and PD were 52.07%±5.78% vs 53.95%±4.62% (P=0.168), 29.62%±6.55% vs 29.50%±6.38% (P=0.940), and 56.93%±6.17% vs 58.15%±5.13% (P=0.407) in PSR and control groups, respectively. The choriocapillary flow density was 61.18±3.25% in PSR group vs 60.88%±2.56% in control group (P=0.692). Also, OCTA found no significant differences in RPCs flow density between PSR and control groups. The optic disc WED, inside disc flow density and peripapillary flow density were 48.47%±4.77% vs 48.11%±4.57% (P=0.813), 45.47%±11.44% vs 46.68%±9.02% (P=0.709), 54.32%±5.29% vs 52.47%±6.62% (P=0.349) in PSR and control groups, respectively. CONCLUSION: OCTA provides a non-invasive and quantitative approach for monitoring macular and papillary blood flow in pathologic myopia. PSR can not improve but may maintain the circulation of pathologic myopia eyes with posterior staphyloma.

13.
J Int Med Res ; 44(3): 557-68, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26951842

RESUMO

OBJECTIVE: To investigate the effects of a knowledge-attitude-behaviour health education model on acquisition of disease-related knowledge and self-management behaviour by patients undergoing maintenance haemodialysis. METHODS: Patients recently prescribed MHD were randomly assigned to a control group or an intervention group. Control group patients were treated with usual care and general education models. A specialist knowledge-attitude-behaviour health education model was applied to patients in the intervention group. RESULTS: Eighty-six patients were included (n = 43 per group). Before intervention, there were no significant between-group differences in disease knowledge and self-management behaviour. After 6 months' intervention, a significant between-group difference in acquisition of disease knowledge was observed. Self-management behaviour scores (control of body mass, reasonable diet, correct drug intake, physical activity, correct fistula care, disease condition monitoring, psychological and social behaviours) for the intervention group were also higher than those for the control group. CONCLUSION: These preliminary findings suggest that the knowledge-attitude-behaviour model appears to be a valuable tool for the health education of MHD patients.


Assuntos
Povo Asiático , Educação em Saúde , Conhecimentos, Atitudes e Prática em Saúde , Diálise Renal , Adulto , Feminino , Humanos , Masculino , Autocuidado
14.
Med Phys ; 42(9): 5278-86, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26328977

RESUMO

PURPOSE: Image-guided localization SPectral Localization Achieved by Sensitivity Heterogeneity (SPLASH) allows rapid measurement of signals from irregularly shaped anatomical compartments without using phase encoding gradients. Here, the authors propose a novel method to address the issue of heterogeneous signal distribution within the localized compartments. METHODS: Each compartment was subdivided into multiple subcompartments and their spectra were solved by Tikhonov regularization to enforce smoothness within each compartment. The spectrum of a given compartment was generated by combining the spectra of the components of that compartment. The proposed method was first tested using Monte Carlo simulations and then applied to reconstructing in vivo spectra from irregularly shaped ischemic stroke and normal tissue compartments. RESULTS: Monte Carlo simulations demonstrate that the proposed regularized SPLASH method significantly reduces localization and metabolite quantification errors. In vivo results show that the intracompartment regularization results in ∼ 40% reduction of error in metabolite quantification. CONCLUSIONS: The proposed method significantly reduces localization errors and metabolite quantification errors caused by intracompartment heterogeneous signal distribution.


Assuntos
Imagem de Difusão por Ressonância Magnética , Espectroscopia de Ressonância Magnética/métodos , Humanos , Método de Monte Carlo , Razão Sinal-Ruído , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/metabolismo , Acidente Vascular Cerebral/patologia
15.
J Chem Phys ; 143(2): 024908, 2015 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-26178128

RESUMO

We investigate the effect of topology on the equilibrium behavior of singly tethered ring polymers adsorbed on an attractive surface. We focus on the change of square radius of gyration Rg(2), the perpendicular component Rg⊥(2) and the parallel component Rg‖(2) to the adsorbing surface, the mean contacting number of monomers with the surface , and the monomer distribution along z-direction during transition from desorption to adsorption. We find that both of the critical point of adsorption εc and the crossover exponent ϕ depend on the knot type when the chain length of ring ranges from 48 to 400. The behaviors of Rg(2), Rg⊥(2), and Rg‖(2) are found to be dependent on the topology and the monomer-surface attractive strength. At weak adsorption, the polymer chains with more complex topology are more adsorbable than those with simple topology. However, at strong adsorption, the polymer chains with complex topology are less adsorbable. By analyzing the distribution of monomer along z-direction, we give a possible mechanism for the effect of topology on the adsorption behavior.


Assuntos
Polímeros/química , Adsorção , Simulação por Computador , Modelos Químicos , Método de Monte Carlo , Propriedades de Superfície
16.
PLoS One ; 9(11): e113256, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25409187

RESUMO

Greater sensory stimulation in advertising has been postulated to facilitate attention and persuasion. For this reason, video ads promoting health behaviors are often designed to be high in "message sensation value" (MSV), a standardized measure of sensory intensity of the audiovisual and content features of an ad. However, our previous functional Magnetic Resonance Imaging (fMRI) study showed that low MSV ads were better remembered and produced more prefrontal and temporal and less occipital cortex activation, suggesting that high MSV may divert cognitive resources from processing ad content. The present study aimed to determine whether these findings from anti-smoking ads generalize to other public health topics, such as safe sex. Thirty-nine healthy adults viewed high- and low MSV ads promoting safer sex through condom use, during an fMRI session. Recognition memory of the ads was tested immediately and 3 weeks after the session. We found that low MSV condom ads were better remembered than the high MSV ads at both time points and replicated the fMRI patterns previously reported for the anti-smoking ads. Occipital and superior temporal activation was negatively related to the attitudes favoring condom use (see Condom Attitudes Scale, Methods and Materials section). Psychophysiological interaction (PPI) analysis of the relation between occipital and fronto-temporal (middle temporal and inferior frontal gyri) cortices revealed weaker negative interactions between occipital and fronto-temporal cortices during viewing of the low MSV that high MSV ads. These findings confirm that the low MSV video health messages are better remembered than the high MSV messages and that this effect generalizes across public health domains. The greater engagement of the prefrontal and fronto-temporal cortices by low MSV ads and the greater occipital activation by high MSV ads suggest that that the "attention-grabbing" high MSV format could impede the learning and retention of public health messages.


Assuntos
Publicidade/métodos , Promoção da Saúde/métodos , Memória , Sexo Seguro/psicologia , Adulto , Preservativos/estatística & dados numéricos , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Sensação , Televisão , Adulto Jovem
17.
J Neurosci ; 33(17): 7420-7, 2013 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-23616548

RESUMO

Televised public service announcements are video ads that are a key component of public health campaigns against smoking. Understanding the neurophysiological correlates of anti-tobacco ads is an important step toward novel objective methods of their evaluation and design. In the present study, we used functional magnetic resonance imaging (fMRI) to investigate the brain and behavioral effects of the interaction between content ("argument strength," AS) and format ("message sensation value," MSV) of anti-smoking ads in humans. Seventy-one nontreatment-seeking smokers viewed a sequence of 16 high or 16 low AS ads during an fMRI scan. Dependent variables were brain fMRI signal, the immediate recall of the ads, the immediate change in intentions to quit smoking, and the urine levels of a major nicotine metabolite cotinine at a 1 month follow-up. Whole-brain ANOVA revealed that AS and MSV interacted in the inferior frontal, inferior parietal, and fusiform gyri; the precuneus; and the dorsomedial prefrontal cortex (dMPFC). Regression analysis showed that the activation in the dMPFC predicted the urine cotinine levels 1 month later. These results characterize the key brain regions engaged in the processing of persuasive communications and suggest that brain fMRI response to anti-smoking ads could predict subsequent smoking severity in nontreatment-seeking smokers. Our findings demonstrate the importance of the quality of content for objective ad outcomes and suggest that fMRI investigation may aid the prerelease evaluation of televised public health ads.


Assuntos
Promoção da Saúde/métodos , Imageamento por Ressonância Magnética/métodos , Córtex Pré-Frontal/metabolismo , Desempenho Psicomotor/fisiologia , Abandono do Hábito de Fumar/psicologia , Televisão , Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neuroimagem/métodos , Fumar/metabolismo , Fumar/psicologia , Fumar/terapia , Abandono do Hábito de Fumar/métodos , Comportamento Social , Inquéritos e Questionários , Produtos do Tabaco/efeitos adversos , Adulto Jovem
18.
J Chem Phys ; 133(6): 064901, 2010 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-20707585

RESUMO

We perform lattice Monte Carlo simulation using the bond-fluctuation model to examine the conformation and dynamic properties of a single small flexible ring polymer in the matrix of linear chains as functions of the degree of polymerization of the linear chains. The average conformation properties as gauged by the mean-square radius of gyration and asphericity parameter are insensitive to the chain length for all the chain lengths examined (30, 100, 300, and 1000). However, in the longer chain (300 and 1000) samples, there is an increased spread in the distribution of the value of these quantities, suggesting structural heterogeneity. The center-of-mass diffusion of the ring shows a rapid decrease with increasing chain length followed by a more gradual change for the two longer chain systems. In these longer chain systems, a wide spread in the value of the apparent self-diffusion coefficient is also observed, as well as qualitatively different square displacement trajectories among the different samples, suggesting heterogeneity in the dynamics. A primitive path analysis reveals that in these long chain systems, the ring can exist in topologically distinct states with respect to threading by the linear chains. Threading by the linear chain can dramatically slow down and in some cases stall the diffusive motion of the ring. We argue that the life times for these topological conformers can be longer than the disentanglement time of the linear chain matrix, so that the ring exhibits nonergodic behavior on time scales less or comparable to the life time of these conformers. Our results suggest a picture of the ring diffusion as one where the diffusion path consists of distinctive segments, each corresponding to a different conformer, with slow interconversion between the different conformers.

19.
Ying Yong Sheng Tai Xue Bao ; 19(10): 2182-8, 2008 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-19123353

RESUMO

Vegetation restoration capacity of disturbed grassland ecosystem is one of the important components in assessing the influence of human engineering activities on the grassland ecosystems in permafrost region of Qinghai-Tibet Plateau. After comparing the features of vegetation communities, plant species diversity, grassland primary productivity, and economic group between disturbed and undisturbed communities, the comprehensive vegetation restoration capacity of several grassland communities under destroyed disturbance was assessed by using comprehensive assessment index. The results showed that the restoration of cover and community composition was obvious after 26 years natural restoration, being better for alpine steppes than for alpine meadows. However, the cover of disturbed communities was less than that of undisturbed communities. The restoration of plant species diversity in Stipa purpurea steppe was better than that in other grassland types. The biomass of standing plants restored from 0 to 148.8-489.6 g x m(-2), and that of Kobresia tibetica meadow was the highest (489.6 g x m(-2)). The palatable plants of disturbed communities were lower than those of undisturbed communities except for K. tibetica meadow, in which, the palatable plants were not changeable between disturbed and undisturbed communities. The comprehensive vegetation restoration capacity of alpine steppes was better than that of alpine meadows.


Assuntos
Monitoramento Ambiental , Atividades Humanas , Camada de Gelo , Poaceae/crescimento & desenvolvimento , Altitude , China , Engenharia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA