The Influence of Ammonia and Carbon Dioxide on the Sorption of a Basic Organic Pollutant to a Mineral Surface

Indoor surfaces have a sorptive capacity for organic pollutants which may be significantly influenced by other gases and the pH of the surface. in this research, we examine the influence of a common indoor gaseous acid, CO2, and base, NH3, on the adsorption of a volatile organic base, trimethylamine (TMA), to a mineral surface, zirconium silicate beads. Varying ammonia and CO2 within concentration ranges of indoor relevance substantially influences the sorptive capacity of this mineral surface. Increasing the CO2 mixing ratio to 1000 p.p.m. enhances surface capacity of TMA by 40-50%; increasing the NH3 mixing ratio to 10 p.p.m. decreases the TMA surface capacity by ~5-80% depending on relative humidity. the phenomena of dissolution of TMA into bulk surface water and acid-base chemistry in the surface water do not adequately describe equilibrium adsorption on this surface. Instead, adsorption to the dry solid or to adsorbed water layers appears to dominate. Reduction in the equilibrium partition coefficient, ke, in the presence of NH3 is due to a competition between TMA and ammonia molecules for adsorption sites. Site competition appears to follow the Langmuir competitive model and most ke values range from 0.003-0.045 m

Prevalence of chronic hepatitis B virus infection in Thailand : a systematic review and meta-analysis

Objective: To estimate the number of people living in Thailand with chronic hepatitis B (CHB), a major cause of liver cirrhosis and cancer, in view of the implementation of programs to prevent CHB complications. Methods: Using PubMed/Medline and ScienceDirect, all studies reporting hepatitis B surface antigen (HBsAg) seroprevalence estimates conducted in Thailand and published between 1975 and 2015 were reviewed systematically. Pooled prevalence estimates and their 95% confidence intervals (CIs) were calculated, and potential sources of heterogeneity investigated. Results: A high heterogeneity was observed between prevalence estimates. There was a significant decrease in the 150 estimates of HBsAg prevalence with more recent decades of birth (p < 0.001), even before the implementation of the national universal immunization program in 1992. When restricted to the general population, the pooled prevalence estimate was 5.1% (95% CI 4.3-6.0%), which would translate to an estimated number of individuals with CHB living in Thailand in 2015 as high as three million. Conclusions: The high burden of CHB in Asian countries is a major challenge for the incorporation of national programs to prevent CHB complications within health care systems

Hepatitis B prevalence and associated factors in adults presenting for infection screening in northern Thailand

Background and aims : Hepatitis B is a leading cause of morbidity and mortality worldwide. In view of the World Health Organization 2030 targets, effective screening of chronic infection is crucial. We have assessed the prevalence and risk factors of hepatitis B surface antigen in adults presenting for screening. Methods : Free-of-charge and anonymous services for simultaneous hepatitis B, hepatitis C, human immunodeficiency virus and syphilis screening and counseling were provided in four facilities in northern Thailand. Analyses were performed separately in clients born before integration into the 1992 hepatitis B vaccine Thailand's Expanded Program on Immunization and in clients born afterwards. Results : Between October 2015 and August 2020, hepatitis B surface antigen prevalence was 7.2 % (185/2578) in clients born before 1992 (95 % confidence interval [CI] = 6.2%-8.2 %). In the multivariable analysis, characteristics independently associated with a higher risk of infection were being born male (adjusted odds ratio [aOR] = 1.49, 95 % CI = 1.10-2.01) and being part of a hill tribe (aOR = 1.65, 95 % CI = 1.01-2.70). Forty-two percent were unaware of their infection. In clients born in 1992 or afterwards, prevalence was 1.5 % (43/2933) (95 % CI = 1.1%-2.0 %) and characteristics independently associated with a higher risk were being born between 1992 and 1995 (aOR = 1.90, 95 % CI = 1.00-3.61), being born male (aOR = 2.60, 95 % CI = 1.34-5.07), being part of a hill tribe (aOR = 5.09, 95 % CI = 2.52-10.26) and having ever injected drugs (aOR = 4.33, 95 % CI = 1.23-15.24). Conclusions : Risk factor-based screening would miss many chronic hepatitis cases. Screening all adults once in their lifetime may be beneficial until the second generation of immunized infants have reached adult age