Biomedical subjects

Y J Chou

Publications and source records attributed to Y J Chou.

7 recordsLinked to original sources

PubMed2004

Microbial kinetic analysis of three different types of EBNR process.

The disadvantages of developed biological nutrient removal (BNR) processes (additional energy for liquid circulation and addition of external carbon substrate for denitrification in anoxic zones) were improved by reconfiguring the process into (1) an anaerobic zone followed by multiple stages of aerobic-anoxic zones (TNCU3 process) or (2) anaerobic, oxic, anoxic, oxic zones in sequence (TNCU2 process). These two pilot plants were operated at a recycling sludge ratio of 0.5 without internal recycle of nitrified supernatant. The sludge retention time was maintained at 10 d. The main objective of this study is to analyze the kinetics of different microorganisms in these two processes and A2O process by using the Activated Sludge Model No. 2d. The effective removal efficiency of carbon, total phosphorus and total nitrogen at 87-98%, 92-100% and 63-80%, respectively, were achieved in the testing runs. According to model simulations, the microbial kinetics in the TNCU3 and TNCU2 processes would be affected by different operations. When the step feeding strategy was adopted, the HRT was longer due to the less influent flowrate in the front stages and the microbes would grow in quantities by about 6% in the aerobic reactors. In the followed anoxic reactors, the microbes would decrease in quantities by about 12% due to the dilution effect. The dilution effects in TNCU3 and TNCU2 processes did not take place in A2O process because the recycling mixed liquid from the aerobic reactor to the anoxic reactor still contained particulate components. The XH, XPAO, and XAUT concentrations in the effluent of the last tank were lower when the step-feeding mode was adopted. The TNCU3 and TNCU2 processes could be operated efficiently without nitrified liquid circulation and addition of external carbon substrate for denitrification.

Bacteria↗

PubMed2003

Impact of separating drug prescribing and dispensing on provider behaviour: Taiwan's experience.

In many Asian countries, physicians both prescribe and dispense drugs. This practice is hypothesized to have caused high drug expenditure and widespread prescription of antibiotics in Asia. Recently, Taiwan implemented the separation policy on an experimental basis. This paper's objective is to empirically evaluate the impact of Taiwan's reform to separate drug prescribing and dispensing on drug expenditure and total health expenditure. The research design consists of a pre/post comparison of the experimental with the control sites (difference-in-difference). Separation policy was implemented in Kaohsung and Taipei in March 1997, and expanded to Chia-yi and Taichung in March 1998. Changes in drug prescription behaviour before and after implementation in these two pairs of experimental cities were compared to Hsin-chu and Tainan (control), where separation policy was not implemented during the study period. To reduce resistance, providers in experimental sites were allowed to hire on-site pharmacists and dispense drugs through them if they chose to do so. Our study sample consists of all outpatient visits to clinics in the study sites between December 1996 and June 1998, with a total of 55.23 million claim records. The drug prescription rate, drug expenditure and total health expenditure per visit were the main outcome measures. We found that the probability of prescription and drug expenditure per visit were, respectively, 17-34% and 12-36% less among visits to clinics without on-site pharmacists, compared with the control sites. However, no difference in total health expenditure was found between these two types of visits. Hence, the separation policy could be effective in reducing drug expenditure and affecting prescription behaviour, but is less certain as a policy for reducing total health expenditure. We also found that the policy has practically no effect on clinics that have on-site pharmacists.

Drug Costs↗

PubMed2001

Health insurance and female labor supply in Taiwan.

We examine whether the availability of subsidized health insurance to the non-working population in Taiwan affected the labor force participation of married women. Our empirical identification exploits the fact that such insurance was first made available to wives of government employees, before being made universally available in Taiwan in 1995. We find that the availability of insurance for non-workers was associated with a 4 percentage point decline in labor force participation among married women, with larger declines among women from low income households. Countries considering universal health insurance as in Taiwan should anticipate similar declines in labor force participation.

Employment↗

PubMed1999

Toxicity of nitromusks in early lifestages of South African clawed frog (Xenopus laevis) and zebrafish (Danio rerio).

Musk xylene (MX), musk ketone (MK) and musk moskene (MM) are synthetic nitro-containing fragrances. Due to their inherent lipophilicity and environmental persistence, they are frequently detected in environmental samples and especially in aquatic ecosystems. Despite this, the current environmental toxicity database of nitromusks is limited. Although nitromusks have been shown to accumulate in aquatic organisms, little is known about their potential developmental effects in the respective aquatic species. To investigate the developmental toxicity of these compounds to amphibians and fish, early lifestages of xenopus (Xenopus laevis) and zebrafish (Danio rerio) were exposed to three nitromusks for 96 h to examine the developmental effects of these compounds in the two species. Nitromusk body concentration measurements were carried out in parallel for correlation with potential developmental effects. No increased mortality, malformation or growth inhibition was observed in either species following 96-h exposure to 400 microg/l MX, MK and MM. However, an approximately 20% reduced viability was observed in xenopus larvae when exposed to 400 microg/l MX, MK and MM for 11 days. Xenopus and zebrafish exposed to 10, 153, 871 and 1637 microg/l 14C-MX for 96 h resulted in whole-body concentrations of 0.7 +/- 0.1, 11.1 +/- 1.1, 38.7 +/- 1.9 and 76.3 +/- 18.3 microg/g, and 4.3 +/- 0.6, 73.3 +/- 11.8, 440.0 +/- 72.7 and 664.0 +/- 47.7 microg/g wet body weight, respectively. Exposure of xenopus larvae to 400 microg/l MX, MK and MM for 11 days, resulted in whole body concentrations (extrapolated from gas chromatographic determinations) of 4700 +/- 5000, 1300 + 300 and 4600 + 4800 microg/g wet weight for MX, MK and MM, respectively. The latter toxicity results, in conjunction with the fact that the concentrations used for the above experiments were between 400- and 10000-fold higher than those detected in the environment, suggest that environmental concentrations of nitromusks are not hazardous for early lifestages of fish and amphibians.

Abnormalities, Drug-Induced↗

PubMed1999

Interactions of nitromusk parent compounds and their amino-metabolites with the estrogen receptors of rainbow trout (Oncorhynchus mykiss) and the South African clawed frog (Xenopus laevis).

Nitromusks, musk xylene (MX), musk ketone (MK) and musk moskene (MM) are synthetic fragrances. 4-Amino-MX (4X), 2-amino-MX (2X) and 2-amino-MK (2K) are nitromusk metabolites formed during the sewage treatment process and have been detected in effluent and surface water at concentrations four to 40 times higher than their parent compounds. To date, data to the aquatic toxicity of nitromusk compounds are limited to the parent compounds and the determination of acute and subacute effects in aquatic organisms. No data are available regarding the potential endocrine modulating effects of these compounds and/or their metabolites in aquatic organisms. Therefore, the competitive binding capability of nitromusks and their metabolites to the estrogen receptors (ER) in rainbow trout and xenopus was investigated. No binding of MX, MK and MM to the ER of either species was observed. In contrast, binding to the ER was observed for 4X, 2X and 2K in both species. The IC50 (competitive binding at the ER) of 2X in rainbow trout was 1.3 +/- 1.1 mM. In contrast, 4X, 2X and 2K bound to the xenopus ER with an IC50 of 30.8 +/- 28.5, 12.9 +/- 10.3 and 70.1 +/- 88.3 microM, respectively.

Animals↗

PubMed1992

Mortality trends in the past 20 years in Pu-Li, Taiwan.

This study was based on a survey of the death certificates of Pu-Li Town in Taiwan, issued over the past 20 years from 1966 to 1985. Age-adjusted mortality trends as well as cause-specific mortality trends were analyzed and compared with nationwide Taiwan data. As a whole, Pu-Li had a higher age-adjusted mortality than that of the overall Taiwan area. This finding may result from a higher mortality from tuberculosis in Pu-Li. Based on these data, the five leading causes of death in Pu-Li were cerebro-vascular disease, accident, heart disease, cancer and tuberculosis. Hypertension and diabetes were the 5th and 6th leading causes of death in 1985 and ranked 12th and 13th, respectively, in 1966. This data point out the increasing importance of hypertension and diabetes rates in Pu-Li. Tuberculosis and pneumonia had been controlled, ranking from the 1st and 3rd in 1966 to the 10th and 12th, respectively, in 1985. Suicide, cancer, and accident were usually coded as the single cause of death without other co-existent causes of death noted, so that there was in most instances not much difference between analyses based on the underlying cause of death and multiple causes of death. However, this was not true for hypertension and diabetes. If multiple causes of death were analyzed, only 34.5% of hypertension and 66% of diabetes were coded as the underlying cause of death. 37.2% of cerebro-vascular diseases co-existed with hypertension, and 20.3% of diabetes co-existed with hypertension.

Adolescent↗

PubMed1982

Techniques for virus detection in aquatic sediments.

Laboratory experiments have been undertaken to study the adsorption-desorption of poliovirus to and from marine and freshwater sediments. It was observed that marine sediments retained 99% of added virus, whereas, freshwater sediments adsorbed approximately 40% of the added virus. Ten eluents were investigated for their ability to desorb viruses from a marine sediment. It was found that virus elution from the marine sediment was relatively low and ranged from less than 1% to 44%. Two eluents, urea-lysine and TCA-glycine at pH 9.0, were found to be the most efficient among the eluents tested. Viruses were more easily released from freshwater than from marine sediments. When urea-lysine, beef extract and purified casein were used as eluents, the overall virus recovery ranged from 8% to 22% for the marine sediment and from 23% to 59% for the freshwater sediments. The urea-lysine methods was used for the detection of indigenous enteroviruses in sediments from a closed shellfish bed. Enteroviruses were recovered with concentrations up to 708 TCID50/50 g of sediment.

Adsorption↗