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- Bonk, Fábio A., et al.
(author)
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Investigation by Combined Solid-State NMR and SAXS Methods of the Morphology and Domain Size in Polystyrene-b-Polyethylene Oxide-b-Polystyrene Triblock Copolymers
- 2010
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In: Journal of Polymer Science. Part B, Polymer Physics. - : Wiley. - 0887-6266. ; 48:1, s. 55-64
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Journal article (peer-reviewed)abstract
- The microphase structure of a series of polystyrene-b-polyethylene oxide-b-polystyrene (SEOS) triblock copolymers with different compositions and molecular weights has been studied by solid-state NMR, DSC, wide and small angle X-ray scattering (WAXS and SAXS). WAXS and DSC measurements were used to detect the presence of crystalline domains of polyethylene-oxide (PEO) blocks at room temperature as a function of the copolymer chemical composition. Furthermore, DSC experiments allowed the determination of the melting temperatures of the crystalline part of the PEO blocks. SAXS measurements, performed above and below the melting temperature of the PEO blocks, revealed the formation of periodic structures, but the absence or the weakness of high order reflections peaks did not allow a clear assessment of the morphological structure of the copolymers. This information was inferred by combining the results obtained by SAXS and 1H NMR spin diffusion experiments, which also provided an estimation of the size of the dispersed phases of the nanostructured copolymers.
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- Trang, Phan Minh, et al.
(author)
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Heatwaves and Hospital Admissions for Mental Disorders in Northern Vietnam
- 2016
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In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:5
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Journal article (peer-reviewed)abstract
- Studies in high-income countries have shown an association between heatwaves and hospital admissions for mental disorders. It is unknown whether such associations exist in subtropical nations like Vietnam. The study aim was to investigate whether hospital admissions for mental disorders may be triggered, or exacerbated, by heat exposure and heatwaves, in a low-and middle-income country, Vietnam. For this, we used data from the Hanoi Mental Hospital over five years (2008-2012) to estimate the effect of heatwaves on admissions for mental disorders. A zero-inflated negative binomial regression model accounting for seasonality, time trend, days of week, and mean humidity was used to analyse the relationship. Heatwave events were mainly studied as periods of three or seven consecutive days above the threshold of 35 degrees C daily maximum temperature (90th percentile). The study result showed heatwaves increased the risk for admission in the whole group of mental disorders (F00-79) for more persistent heatwaves of at least 3 days when compared with non-heatwave periods. The relative risks were estimated at 1.04 (0.95-1.13), 1.15 (1.005-1.31), and 1.36 (1-1.90) for a one-, three- and seven-day heatwave, respectively. Admissions for mental disorders increased among men, residents in rural communities, and the elderly population during heatwaves. The groups of organic mental disorders, including symptomatic illnesses (F0-9) and mental retardation (F70-79), had increased admissions during heatwaves. The findings are novel in their focus on heatwave impact on mental diseases in a population habituating in a subtropical low-and middle-income country characterized by rapid epidemiological transitions and environmental changes.
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- Trang, Phan Minh, et al.
(author)
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Seasonality of hospital admissions for mental disorders in Hanoi, Vietnam
- 2016
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In: Global Health Action. - : Informa UK Limited. - 1654-9716 .- 1654-9880. ; 9
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Journal article (peer-reviewed)abstract
- BACKGROUND: Some studies have shown a relationship between seasonality in weather patterns and depressive and behavioural disorders, especially in temperate climate regions. However, there is a lack of studies describing the seasonal patterns of hospital admissions for a variety of mental disorders in tropical and subtropical nations. The aim of this study has been to examine the relationship between seasons and daily hospital admissions for mental disorders in Hanoi, Vietnam.DESIGNS: A 5-year database (2008-2012) compiled by Hanoi Mental Hospital covering mental disorder admissions diagnosed by the International Classification of Diseases 10 was analysed. A negative binominal regression model was applied to estimate the associations between seasonality and daily hospital admissions for mental disorders, for all causes and for specific diagnoses.RESULTS: The summer season indicated the highest relative risk (RR=1.24, confidence interval (CI)=1.1-1.39) of hospital admission for mental disorders, with a peak in these cases in June (RR=1.46, CI=1.19-1.7). Compared to other demographic groups, males and the elderly (aged over 60 years) were more sensitive to seasonal risk changes. In the summer season, the RR of hospital visits among men increased by 26% (RR=1.26, CI=1.12-1.41) and among the elderly by 23% (RR=1.23, CI=1.03-1.48). Furthermore, when temperatures including minimum, mean, and maximum increased 1°C, the number of cases for mental disorders increased by 1.7%, 2%, and 2.1%, respectively.CONCLUSION: The study results showed a correlation between hospital admission for mental disorders and season.
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5. |
- Trang, Phan Minh, 1974-
(author)
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Weather and extreme heat in association to mental disorders : The case of Hanoi, Vietnam
- 2017
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Doctoral thesis (other academic/artistic)abstract
- Background: Vietnam suffers consequences of global warming. There is limited data of the relationship between weather, extreme heat and potential mental health problems. It is therefore crucial to study heat-related mental illnesses and to establish good solutions with relevant adaptations to global warming. The adaptation measures should give attention to people that live in areas facing annual extreme weather, and protecting health in general and more specifically mental health of citizens. The study aimed to examine relationships between weather patterns, extreme heat or heatwaves, and mental disorders, and to investigate factors contributing to increased vulnerability and susceptibility.Methods: The thesis includes a systematic review and a hospital-based study using data from the Hanoi Mental Hospital for five years (2008 – 2012), with mental disorders diagnosed by ICD10 (F00-99) to estimate the effects of weather variation, seasonality, increased temperatures, and heatwaves on hospital admissions for depression and other mental disorders. A negative binomial regression model accounting for yearly study period, time trends, and day of the week was used to analyze the relationship between seasonality, heatwaves, and monthly and daily mental disorder hospitalizations.Results: Our findings showed (i) a general tendency for more admissions between May and December, with a seasonal bi-annual high between May-June and November-December, and elevated ambient temperature was significantly related to increasing admissions for depressive disorders; (ii) the number of hospital cases for mental disorders increased in the summer seasone specially in June, and two percent of cases emerged during elevated temperature of one degree Celsius; and (iii) when compared with non-heatwave periods, heatwaves amounted to increasing risks for admission for the whole group of mental disorders (F00-79), and admissions for mental disorders among residents in rural communities and in the elderly population increased significantly during heatwaves.Conclusion: There were associations between hospital admissions for depression and other mental disorders and seasonality, weather patterns, elevated temperatures, and heatwaves. The associations grew stronger with the length of the heatwaves and particularly the elderly appeared more sensitive to seasonality, hot weather and heatwaves.
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6. |
- Trang, Phan Minh, et al.
(author)
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Weather Variations and Hospital Admissions for Depressive Disorders : A Case Study in Hanoi
- 2015
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In: Annals of Psychiatry and Mental Health. - : JSciMed Central. - 2374-0124. ; 3:1
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Journal article (peer-reviewed)abstract
- Studies from developed countries have shown season and weather influencing mood disorders, but it is not known whether such associations exist in tropical/sub-tropical low- and middle-income countries. This study from Vietnam examined the seasonal pattern of hospital admissions for depressive disorders andits relationship to daily weather variations, after stratifying for age, sex, and geographic area. Daily admission data from 2008 to 2012 were collected from Hanoi Mental Hospital in which 619 first-episode admissions for depressive disorders were diagnosed by the International Classification of Diseases 10 criteria for mood disorders (F30–F39). A negative binominal time series regression model for daily counts of eventswasestablished to analyze the relationship between weather variations, seasonality and daily hospital admissions for depressive disorders after adjusting for time trends. Our findings showed a general tendency for more admissionsin 2010 as well as between May and December, with a seasonal bi-annual high between May-June and November-December. Males were more affected by high ambient temperature and sunshine-hours. Elevated ambient temperature was significantly related to increasing admissions RR=1.05 (1.01 – 1.09) over the same or following day. The relationship between hours of sunshine and the number of cases indicateda significant linear associationin menwhen the number of hours of sunlight per day was over each one hour RR=1.06 (1.02 – 1.11). High temperatures and high numbers of sunshine hours had a strong positive relationship to admission with a delay of 0–13 days. For these associations, men and ages below 40 years appeared more susceptible
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