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Bangkok, Thailand

Intarapong P.,Chulalongkorn University | Jindavat C.,Chulalongkorn University | Luengnaruemitchai A.,Chulalongkorn University | Jai-In S.,Royal Thai Navy
International Journal of Green Energy | Year: 2014

In this study, KOH/bentonite catalysts, prepared by the impregnation method, were studied for transesterification in a continuous reactor. The catalysts were characterized using X-ray diffraction, Fourier transform infrared spectrophotometry, scanning electron microscopy, nitrogen adsorption/ desorption, CO2 temperature programmed desorption, and X-ray fluorescence. The results showed that the addition of 20 wt% K on the bentonite catalyst at 60°C reaction temperature, methanol/oil molar ratio of 15:1, and flow rate of 0.3 ml/min gave a biodiesel content exceeding 75%. With increasing basicity, the presence of K2O was observed, and the biodiesel content was improved. In addition, there was negligible loss in activity when the catalyst was operated at 60°C for 7 days. A minimum level of potassium leaching on the 20 wt% K/bentonite was observed during the run. © Taylor & Francis Group, LLC. Source


Luksamijarulkul P.,Mahidol University | Aiempradit N.,Royal Thai Navy | Vatanasomboon P.,Mahidol University
Oman Medical Journal | Year: 2014

Objective: To assess the relationship of bacterial and fungal contamination on used surgical masks worn by the hospital personnel and microbial air quality in their working wards.Methods: This is a cross-sectional study of 230 used surgical masks collected from 214 hospital personnel, and 215 indoor air samples collected from their working wards to culture for bacterial and fungal counts. This study was carried out at the hospital in Bangkok. Group or genus of isolated bacteria and fungi were preliminarily identified by Gram’s stain and lacto-phenol cotton blue. Data were analyzed using paired t-test and Pearson’s correlation coefficient at the significant level of p<0.050.Results: Means and standard deviation of bacterial and fungal contamination on inside area of the used masks were 47 ± 56 and 15 ± 9 cfu/ml/piece, and on outside area were 166 ± 199 and 34 ± 18 cfu/ml/piece, respectively, p<0.001. The bacterial and fungal contamination on used masks from hospital personnel working in the male and female medical wards and out-patient department, as well as the bacterial and fungal counts of the indoor air sample collected from the same area were relatively higher than the other wards. The predominant isolated bacteria and fungi contaminated on inside and outside areas of the used masks and air samples were similar (Staphylococcus spp. and Aspergillus spp.; respectively). For its relationship, results found that bacterial and fungal counts in air samples showed significantly positive correlation with the bacterial contamination load on outside area of the used masks, r=0.16, p=0.018 and r=0.21, p=0.003, respectively.Conclusion: High bacterial contamination on outside area of the used masks was demonstrated, and it showed a significant correlation with microbial air quality of working wards. © OMSB, 2014. Source


Lerdsamran H.,Mahidol University | Pittayawonganon C.,Bureau of Epidemiology | Pooruk P.,Mahidol University | Mungaomklang A.,Maharat Nakhonratchasima Hospital | And 15 more authors.
PLoS ONE | Year: 2011

Background: Individuals infected with the 2009 pandemic virus A(H1N1) developed serological response which can be measured by hemagglutination-inhibition (HI) and microneutralization (microNT) assays. Methodology/Principal Findings: MicroNT and HI assays for specific antibody to the 2009 pandemic virus were conducted in serum samples collected at the end of the first epidemic wave from various groups of Thai people: laboratory confirmed cases, blood donors and health care workers (HCW) in Bangkok and neighboring province, general population in the North and the South, as well as archival sera collected at pre- and post-vaccination from vaccinees who received influenza vaccine of the 2006 season. This study demonstrated that goose erythrocytes yielded comparable HI antibody titer as compared to turkey erythrocytes. In contrast to the standard protocol, our investigation found out the necessity to eliminate nonspecific inhibitor present in the test sera by receptor destroying enzyme (RDE) prior to performing microNT assay. The investigation in pre-pandemic serum samples showed that HI antibody was more specific to the 2009 pandemic virus than NT antibody. Based on data from pre-pandemic sera together with those from the laboratory confirmed cases, HI antibody titers ≥40 for adults and ≥20 for children could be used as the cut-off level to differentiate between the individuals with or without past infection by the 2009 pandemic virus. Conclusions/Significance: Based on the cut-off criteria, the infection rates of 7 and 12.8% were estimated in blood donors and HCW, respectively after the first wave of the 2009 influenza pandemic. Among general population, the infection rate of 58.6% was found in children versus 3.1% in adults. © 2011 Lerdsamran et al. Source


Wongwises P.,King Mongkuts University of Technology Thonburi | Vongvisessomjai S.,TEAM Consulting Engineering and Management Co. | Lueangaram W.,Royal Thai Navy
American Journal of Environmental Sciences | Year: 2010

Problem statement: A two-dimensional wave prediction model along the best track of Typhoon Linda 1997 was interested to study the impact of typhoon wind-wave characteristics. The dynamical wave model with deep water condition was used to predict the wave height (Hs) of Typhoon Linda before and after entering into the Gulf of Thailand (GoT). Approach: The standard one-way nested grid for a regional scale of the third generation WAve Model Cycle 4 (WAMC4) is scrutinized in the present study. This model is enabled to solve the spectral energy balance equation on a coarse resolution grid in order to produce boundary conditions for a small area by the nested grid technique along the best track of typhoon. The model takes full advantage of the fine resolution wind fields in space and time produced by the available US Navy Operational Global Atmospheric Prediction System (NOGAPS) model with 1° resolution. The nested grid application was developed in order to gradually increase the resolution from the open ocean towards the South China Sea (SCS) and the Gulf of Thailand (GoT) respectively. Results: The model results were predicted at five stations which were before and during the typhoon entering into the GoT. The wind speeds of the stations 1-5 were in ranges of 5.14-29.81, 4.11-28.27, 0.51-24.67, 0.51-31.35 and 0.51-33.41 m sec-1, respectively. While the Hs of these stations were found in ranges of 0.54-2.99, 0.68-2.85, 0.11-1.57, 0.12-2.92 and 0.09-2.76 m, respectively. The model results were compared with buoy observations at Ko-Chang and Rayong locations in the GoT which were obtained from the Seawatch project. The comparison of those results at Ko-Chang and Rayong showed the percentage errors of 11.20 and 15.12% respectively. Conclusion: The model results presented the relationship of typhoon wind-induced ocean wave at five stations along the best track. The tendency of the Hs from the model in the spherical coordinate propagation with deep water condition in the fine grid domain was in good agreement with the Hs from the observations. © 2010 Science Publications. Source


Yuntadilok N.,Mahidol University | Timmuang R.,Hua Chiew Chalermprakiet University | Timsard S.,Royal Thai Navy | Guadamuz T.E.,University of Pittsburgh | And 4 more authors.
AIDS and Behavior | Year: 2014

Despite extensive early prevention efforts, recent surveys suggest that sexual risk taking may again be on the rise in Thailand. The present cross-sectional study surveyed 3,299 recruits in the Thai Navy in 2010, to examine their rates and correlates of consistent condom use. Most participants were aged 21-22 years, unmarried, and had a secondary education. Almost half were employed in labor/agriculture. Only 17 % of sexually experienced recruits were consistent condom users, and 53 % reported multiple sex partners in the past 3 months. In multiple logistic regression, residence in the Northeast (AOR 1.47), age (AOR 1.43), being single (AOR 2.13), non-MSM status (AOR 1.41), voluntary testing (AOR 1.24), and condom use at first sex (AOR 4.29) were significantly associated with consistent condom use. These findings suggest gaps in Thailand's condom campaign targeting both sexually experienced and inexperienced youth. Interventions targeting naval recruits may benefit from including sex education in the training curriculum, building drillmasters' capacities to facilitate sex education/counseling, and creating a supportive environment with better access to condoms. © Springer Science+Business Media New York 2013. Source

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