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Newman P.A.,University of Toronto | Lee S.-J.,University of California at Los Angeles | Roungprakhon S.,Rajamangala University of Technology at Phra Nakhon | Tepjan S.,University of Toronto
Prevention Science

High HIV prevalence among men who have sex with men (MSM) and transgender women in Thailand suggest a vital need for targeted interventions. We conducted a cross-sectional survey to examine and compare sexual risk behaviors, and demographic and behavioral correlates of risk, among MSM and transgender women recruited from gay entertainment venue staff and community-based organization (CBO) participants. We used venue-based sampling across nine sites in Bangkok and Chiang Mai. Among 260 participants (57. 3% gay-identified, 26. 9% heterosexual/bisexual-identified, 15. 8% transgender; mean age = 26. 7 years), nearly one-fifth (18. 5%) reported unprotected anal sex (UAS), half (50. 4%) sex in exchange for money, and one-fifth (20. 0%) STI diagnosis (past year). Nearly one-fourth (23. 1%) reported oral erectile dysfunction medication use and nearly one-fifth (19. 2%) illicit drug use (past 3 months). Overall, 43. 1% indicated that healthcare providers exhibited hostility towards them. Gay entertainment venue staff were significantly more likely to self-identify as heterosexual/bisexual (versus gay or transgender female), and to have less than high school degree education, higher monthly income, to have engaged in sex in exchange for money, sex with women and unprotected vaginal sex, but were significantly less likely to have engaged in UAS than CBO participants. Targeted interventions for younger MSM and transgender women, for non gay-identified men, and strategies to address structural determinants of risk, including low education and discrimination from healthcare providers, may support HIV prevention among MSM and transgender women, and serve broader national HIV prevention efforts in Thailand. © 2012 Society for Prevention Research. Source

Rukzon S.,Rajamangala University of Technology at Phra Nakhon | Chindaprasirt P.,Khon Kaen University
Materials and Design

This paper presents the use of bagasse ash (BA) as a pozzolanic material for producing high-strength concrete. Portland cement type I (PC) is partially replaced with finely ground bagasse ash. The concrete mixtures, in part, are replaced with 10%, 20% and 30% of BA respectively. In addition, the compressive strength, the porosity, the coefficient of water absorption, the rapid chloride penetration and the chloride diffusion of concretes are determined. The test results indicate that the incorporation of BA up to 30% replacement level increases the resistance to chloride penetration. Besides, the use of 10% of BA produced concretes with good strength and low porosity. Reasonably, the substitution of 30% BA is acceptable for producing high-strength concrete. © 2011 Elsevier Ltd. Source

Rukzon S.,Rajamangala University of Technology at Phra Nakhon | Chindaprasirt P.,Khon Kaen University
Advances in Civil Engineering

This paper presents the use of blend of Portland cement with rice husk-bark ash in producing self-compacting concrete (SCC). CT was partially replaced with ground rice husk-bark ash (GRHBA) at the dosage levels of 0%-40% by weight of binder. Compressive strength, porosity, chloride penetration, and corrosion of SCC were determined. Test results reveal that the resistance to chloride penetration of concrete improves substantially with partial replacement of CT with a blend of GRHBA and the improvement increases with an increase in the replacement level. The corrosion resistances of SCC were better than the CT concrete. In addition, test results indicated that the reduction in porosity was associated with the increase in compressive strength. The porosity is a significant factor as it affects directly the durability of the SCC. This work is suggested that the GHRBA is effective for producing SCC with 30% of GHRBA replacement level. © 2014 Sumrerng Rukzon and Prinya Chindaprasirt. Source

Chindaprasirt P.,Khon Kaen University | Chotetanorm C.,Khon Kaen University | Rukzon S.,Rajamangala University of Technology at Phra Nakhon
Journal of Materials in Civil Engineering

This paper presents the use of palm oil fuel ash as a pozzolanic material in producing high-strength and high-workability concrete. Portland cement Type I (CT) was partially replaced with ground palm oil fuel ash (PA). PA with 2-5% by weight retained on a sieve No. 325 was used. The concrete mixtures were made with portland cement Type I containing 10, 20, and 30% of PA. Compressive strength, coefficient of water absorption, rapid chloride penetration and corrosion resistance of concretes were determined. Test results indicated that the high-strength high-workability concrete can be achieved by using PA to replace portland cement Type I up to 20%. The resistance to chloride-induced corrosion of concrete containing PA as measured by accelerated corrosion test with impressed voltage is significantly improved in comparison to that of CT concrete. © 2011 American Society of Civil Engineers. Source

Chansuvarn W.,Rajamangala University of Technology at Phra Nakhon | Tuntulani T.,Chulalongkorn University | Imyim A.,Chulalongkorn University
TrAC - Trends in Analytical Chemistry

This review focuses on colorimetric and visual assays for determination of mercury(II) (Hg2+) ions based on gold nanoparticles (AuNPs), fluorescent gold nanoclusters (AuNCs), gold nanorods (AuNRs), gold nanoflowers (AuNFs) and gold nanostars (AuNSs). The analytical colorimetric approaches based on AuNPs can be categorized according to the aggregation or disaggregation mechanisms of functionalized or unmodified AuNPs. The colorimetric concept involves change of the color of a solution of AuNPs from deep red to purple or blue. Disaggregation assays involve reversing the color from blue to red. Detection using AuNCs is based on Hg2+-induced fluorescence quenching of functionalized AuNCs and label-free AuNCs. The benefits of these systems are simplicity, rapidity, cost-effective production, ease of usage, easy visualization of the color change, and detection using spectrophotometry, fluorometry and the naked eye. We summarize applications to real samples, limits of detection, and the development of test strips. © 2014 . Source

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