PubMed Health⌕ Search

Biomedical subjects

Y W Tsai

Publications and source records attributed to Y W Tsai.

8 recordsLinked to original sources
PubMed2001

In situ EXAFS investigation of carbon-supported Pt clusters under potential control.

The transformation of carbon supported Pt clusters under potential control in 1M HClO4 solution was investigated by in-situ X-ray absorption spectroscopy measurements. Both XANES and EXAFS data are used to show the structure evolution of the Pt clusters at various potentials. It showed that the white line area and the edge energy increase with the applied potential in the range 0.1-1.5V. The coordination number of oxygen and platinum on the Pt/C electrode increases and decreases, respectively, with the applied potential. It is found that the size of Pt cluster does not grow during the electrode fabrication. However, the crystallization of Pt cluster occurs during the potential cycling.

Journal Article↗
PubMed2000

Three-dimensional modelling of the catalytic domain of Streptococcus mutans glucosyltransferase GtfB.

Glucosyltransferases (GtfB/C/D) of Streptococcus mutans, a pathogen for human dental caries, synthesize water-insoluble glucan through the hydrolysis of sucrose. Genetic and biochemical approaches have identified several active sites of these enzymes, but no three-dimensional (3D) structural evidence is yet available to elucidate the subdomain arrangement and molecular mechanism of catalysis. Based on a combined sequence and secondary structure alignment against known crystal structures of segments from closely related proteins, we propose here the 3D model of an N-terminal domain essential for the sucrose binding and splitting in GtfB. A Tim-barrel of (alpha/beta)(8) structural characteristics is revealed and the structural correlation for two peptides is described.

Amino Acid Sequence↗
PubMed2000

Cigarette consumption in rural China: survey results from 3 provinces.

OBJECTIVES: This study assessed cigarette consumption and its main determinants in rural China. METHODS: A logistic regression model was used to analyze status of smoking, daily amount of smoking, and expense of cigarettes in rural China. RESULTS: Approximately 57.1% of the males and 3.1% of the females were current smokers. The daily amount of smoking among smokers was 15.23 cigarettes, and their annual expenses were 227 yuan. CONCLUSIONS: People in rural China consume fewer cigarettes and are less likely to smoke than those in urban areas. Education and occupation are 2 major factors that determine the likelihood of smoking in rural China.

Adolescent↗
PubMed2000

Children of working low-income families in California: does parental work benefit children's insurance status, access, and utilization of primary health care?

OBJECTIVE: To examine financial and nonfinancial access to care and utilization of primary health care services among children of working low-income families earning below 200 percent of the federal poverty level in California, and to compare them to children in nonworking low-income families and in families earning over 200 percent of poverty. DATA SOURCES/STUDY SETTING: The 1994 National Health Interview survey weighted to reflect population estimates for California. STUDY DESIGN: This cross-sectional study of 3,831 children under age 19 focuses on financial access, that is, the prevalence and continuity of health insurance coverage; structural access, including the presence of a usual source of care, the predominant care source, its responsiveness to patient's needs, and any indications of delayed or missed care; and utilization of health care measured by the presence of an outpatient doctor's visit and the mean number of visits relative to child health status. DATA COLLECTION: The study uses secondary analysis. FINDINGS: Compared to children of nonworking low-income parents and to nonpoor children, children of working low-income parents were more likely to be uninsured (32.1 percent versus 15.6 percent and 10.3 percent, p = .0001) and to experience disruptions in insurance coverage (p = .0009). These differences persisted after controlling for other covariates in multivariate analyses. Children of working low-income parents did not differ significantly from children of nonworking low-income parents on measures of structural access or utilization, after adjusting for other covariates. However, they differed significantly from nonpoor children on structural access and utilization, and these differences mostly persisted after adjusting for other covariates (odds ratios from 1.5 to 2.9). Similar patterns were observed when children of full-time, year-round working parents with low earnings were compared with the two reference populations. CONCLUSION: Children in working low-income families in California have some of the worst access problems. Even full attachment to the workforce does not guarantee health insurance benefits, access to care, or improved health care use for children of low-income parents. These children are not better off than other low-income children of nonworking parents and are much worse off than nonpoor children. Expansion of health insurance coverage through Healthy Families and Medi-Cal, and attention to nonfinancial barriers to care for working low-income families may help to reduce these disparities.

Adolescent↗
PubMed1998

Differentiation of lactate-fermenting, gas-producing Clostridium spp. isolated from milk.

Endospores of Clostridium spp. capable of producing gas in a lactate-containing medium were enumerated from 14 pasteurized milk samples from Wisconsin cheese plants. Concentrations of endospores of lactate-fermenting, gas-producing Clostridium spp. were between 5.0 x 10(-2) and 1.7 x 10(0) MPN ml(-1). Concentrations of presumptive C. tyrobutyricum endospores (defined by subterminal endospore position and lactate dehydrogenase activity) were lower, not exceeding 2.0 x 10(-2) MPN ml(-1). Based on subterminal endospore position, lactate dehydrogenase activity, and a carbohydrate fermentation profile identical to C. tyrobutyricum strain ATCC 25755, five isolates (Ct) were initially characterized as C. tyrobutyricum, a known cause of late-blowing in high-pH cheeses. Twenty-eight other isolates (Cx) produced gas from lactate, but differed from ATCC 25755 in either endospore position, lactate dehydrogenase activity or carbohydrate fermentation profile. When inoculated at high concentrations in Gouda cheese, strain ATCC 25755, two Ct isolates and 18 Cx isolates tested produced gas during ripening. Among the five Ct isolates obtained and two reference strains confirmed as C. tyrobutyricum, there were four qualitatively different volatile organic acid byproduct profiles. Each of the two confirmed C. tyrobutyricum reference strains and five Ct isolates had distinct quantitative cell membrane fatty acid (CMFA) profiles. The Cx isolates represented 14 different volatile organic acid byproduct profiles and each isolate had a unique CMFA profile. Pulsed field gel electrophoresis (PFGE) of DNA from the two confirmed reference C. tyrobutyricum strains, four Ct and three Cx isolates, showed a low degree of relatedness. The results of this study suggest that a heterogeneous group of lactate-fermenting, gas-producing Clostridium spp. may be found in milk. Gas chromatographic analysis of volatile organic acid byproducts or CMFA, and PFGE of DNA are highly discriminating methods for differentiating Clostridium spp. that may cause late blowing in high-pH cheeses.

Animals↗
PubMed1995

T-tube drainage for the treatment of high jejunal atresia.

Since 1976, the authors have used T-tube drainage for the treatment of diaphragmatic type, high jejunal atresia. Twelve cases were operated on. All cases survived the operation. On the fourteenth to thirtieth postoperative day, T-tubes were removed when the dilated proximal intestine returned to normal size.

Drainage↗
PubMed1989

Adult Hirschsprung's disease.

This report presents a series of 17 patients with adult Hirschsprung's disease treated at the National Taiwan University Hospital and its affiliated hospitals from 1965 to 1988. Adults with Hirschsprung's disease may present with symptoms and operative findings different from those of children with Hirschsprung's disease. The symptoms, signs, criteria for diagnosis, operative findings, and operative procedures are presented.

Adolescent↗