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S Y Yuan

Publications and source records attributed to S Y Yuan.

At least 19 recordsLinked to original sources
PubMed2006

Biodegradation of nonylphenol in soil.

We investigated the effects of various factors (brij 30, brij 35, yeast extract, hydrogen peroxide and compost) on the aerobic degradation of nonylphenol (NP) in soil and characterized the structure of the microbial community in that soil. Residues of NP were measured using gas chromatography-mass spectrometry (GC-MS) and a change of microbial communities was demonstrated using denaturing gradient gel electrophoresis (DGGE). The results showed that Taichung sandy clay loam had higher NP degradation rate than Kaoshiung silty clay. The addition of compost, yeast extract (0.5 mg/l), brij 30 (55 microM), or brij 35 (91 microM) enhanced NP degradation, while the addition of hydrogen peroxide (1.0 mg/l) inhibited its degradation. We also found that the addition of various substrates changed the microbial community in the soils. Cytophaga sp. and Ochrobactrum sp. were constantly dominant bacteria under various conditions in the soil.

Analysis of Variance↗
PubMed2006

Plasma glucose levels and diabetes are independent predictors for mortality and morbidity in patients with SARS.

AIMS: To investigate the relationships between a known history of diabetes and ambient fasting plasma glucose (FPG) levels with death and morbidity rates in patients with severe acute respiratory syndrome (SARS). METHODS: In this retrospective analysis, the clinical and biochemical characteristics of 135 patients who had died from SARS, 385 survivors of SARS and 19 patients with non-SARS pneumonia were compared. RESULTS: All patients were treated according to a predefined protocol. Before steroid treatment, the mean FPG level was significantly higher in the SARS group (deceased vs. survivors vs. non-SARS pneumonia group: 9.7 +/- 5.2 vs. 6.5 +/- 3.0 vs. 5.1 +/- 1.0 mmol/l, P < 0.01). In the SARS group, the percentage of patients with a known history of diabetes was significantly higher in the deceased patients than in the survivors (21.5% vs. 3.9%, P < 0.01). Among patients with no known history of diabetes and before commencement of steroid therapy, those who had hypoxaemia (SaO(2) < 93%) had higher FPG levels than those who did not have hypoxia in both the survivor (8.7 +/- 4.9 vs. 6.3 +/- 2.1 mmol/l, P < 0.001) and deceased (9.8 +/- 4.8 vs. 7.2 +/- 1.5 mmol/l, P < 0.001) groups. A known history of diabetes [odds ratio (OR) 3.0, 95% confidence interval (CI) 1.4, 6.3; P = 0.005] and FPG > or = 7.0 mmol/l before steroid treatment (OR 3.3, 95% CI 1.4, 7.7, P = 0.006) were independent predictors of death. During the course of the illness, FPG levels were negatively associated with SaO(2) (beta =-0.682 +/- 0.305, P = 0.025, general estimation equation model) in SARS patients. Survival analysis showed that FPG was independently associated with an increased hazard ratio (HR) of mortality (HR = 1.1, 95% CI 1.0, 1.1, P = 0.001) and hypoxia (HR = 1.1, 95% CI 1.0, 1.1, P = 0.002) after controlling for age and gender. CONCLUSIONS: A known history of diabetes and ambient hyperglycaemia were independent predictors for death and morbidity in SARS patients. Metabolic control may improve the prognosis of SARS patients.

Adult↗
PubMed2005

Biodegradation of nonylphenol in sewage sludge.

We investigated the effects of various factors on the aerobic degradation of nonylphenol (NP) in sewage sludge. NP (5 mg/kg) degradation rate constants (k1) calculated were 0.148 and 0.224 day(-1) for the batch experiment and the bioreactor experiment, respectively, and half-lives (t(1/2)) were 4.7 and 3.1 days, respectively. The optimal pH value for NP degradation in sludge was 7.0 and the degradation rate was enhanced when the temperature was increased and when yeast extract (5 mg/l) and surfactants such as brij 30 or brij 35 (55 or 91 microM) were added. The addition of aluminum sulfate (200 mg/l) and hydrogen peroxide (1 mg/l) inhibited NP degradation within 28 days of incubation. Of the microorganism strains isolated from the sludge samples, we found that strain CT7 (identified as Bacillus sphaericus) manifested the best degrading ability.

Bacillus↗
PubMed2005

Anaerobic degradation of diethyl phthalate, di-n-butyl phthalate, and di-(2-ethylhexyl) phthalate from river sediment in Taiwan.

We investigated anaerobic degradation rates for three phthalate esters (PAEs), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), and di-(2-ethylhexyl) phthalate (DEHP), from river sediment in Taiwan. The respective anaerobic degradation rate constants for DEP, DBP, and DEHP were observed as 0.045, 0.074, and 0.027 1/day, with respective half-lives of 15.4, 9.4, and 25.7 days under optimal conditions of 30 degrees C and pH7.0. Anaerobic degradation rates were enhanced by the addition of the surfactants brij 35 and triton N101 at a concentration of 1 critical micelle concentration (CMC), and by the addition of yeast extract. Degradation rates were inhibited by the addition of acetate, pyruvate, lactate, FeCl3, MnO2, NaCl, heavy metals, and nonylphenol. Our results indicate that methanogen, sulfate-reducing bacteria, and eubacteria are involved in the degradation of PAEs.

Animals↗
PubMed2005

Anaerobic degradation of nonylphenol in sludge.

We investigated the effects of various factors on the anaerobic degradation of nonylphenol (NP) in sludge. NP (5 mg/l) anaerobic degradation rate constants were 0.029 1/day for sewage sludge and 0.019l/day for petrochemical sludge, and half-lives were 23.9 days and 36.5 days respectively. The optimal pH for NP degradation in sludge was 7 and the degradation rate was enhanced when the temperature was increased. The addition of yeast extract (5 mg/l) or surfactants such as brij 30 or brij 35 (55 or 91 microM) also enhanced the NP degradation rate. The addition of aluminum sulfate (200 mg/l) inhibited the NP degradation rate within 84 days of incubation. The high-to-low order of degradation rates was: sulfate-reducing conditions>methanogenic conditions>nitrate-reducing conditions. Sulfate-reducing bacteria, methanogen, and eubacteria are involved in the degradation of NP, sulfate-reducing bacteria being a major component of sludge.

Anaerobiosis↗
PubMed2004

Biodegradation of phthalate esters by two bacteria strains.

In this study two aerobic phthalic acid ester (PAE) degrading bacteria strains, DK4 and O18, were isolated from river sediment and petrochemical sludge, respectively. The two strains were found to rapidly degrade PAE with shorter alkyl-chains such diethyl phthalate (DEP), dipropyl phthalate (DPrP), di-n-butyl phthalate (DBP), benzylbutyl phthalate (BBP) and diphenyl phthalate (DPP) are very easily biodegraded, while PAE with longer alkyl-chains such as dicyclohexyl phthalate (DCP) and dihexyl phthalate (DHP) and di-(2-ethylhexyl) phthalate (DEHP) are poorly degraded. The degradation rates of the eight PAEs were higher for strain DK4 than for strain O18. In the simultaneous presence of strains DK4 and O18, the degradation rates of the eight PAEs examined were enhanced. When the eight PAEs were present simultaneously, degradation rates were also enhanced. We also found that PAE degradation was delayed by the addition of nonylphenol or selected polycyclic aromatic hydrocarbons (PAHs) at a concentration of 1 microg/g in the sediment. The bacteria strains isolated, DK4 and O18, were identified as Sphigomonas sp. and Corynebacterium sp., respectively.

Biodegradation, Environmental↗
PubMed2004

Degradation of nonylphenol by anaerobic microorganisms from river sediment.

We investigated the degradation of nonylphenol monoethoxylate (NP1EO) and nonylphenol (NP) by anaerobic microbes in sediment samples collected at four sites along the Erren River in southern Taiwan. Anaerobic degradation rate constants (k1) and half-lives (t1/2) for NP (2 microg/g) ranged from 0.010 to 0.015 1/day and 46.2 to 69.3 days respectively. For NP1EO (2 microg/g), the ranges were 0.009-0.014 1/day and 49.5-77.0 days respectively. Degradation rates for NP and NP1EO were enhanced by increasing temperature and inhibited by the addition of acetate, pyruvate, lactate, manganese dioxide, ferric chloride, sodium chloride, heavy metals, and phthalic acid esters. Degradation was also measured under three anaerobic conditions. Results show the high-to-low order of degradation rates to be sulfate-reducing conditions > methanogenic conditions > nitrate-reducing conditions. The results show that sulfate-reducing bacteria, methanogen, and eubacteria are involved in the degradation of NP and NP1EO, with sulfate-reducing bacteria being a major component of the river sediment.

Bacteria, Anaerobic↗
PubMed2004

Biodegradation of nonylphenol in river sediment.

We investigated the biodegradation of nonylphenol monoethoxylate (NP1EO) and nonylphenol (NP) by aerobic microbes in sediment samples collected at four sites along the Erren River in southern Taiwan. Aerobic degradation rate constants (k1) and half-lives (t1/2) for NP (2 microg g(-1)) ranged from 0.007 to 0.051 day(-1) and 13.6 to 99.0 days, respectively; for NP1EO (2 microg g(-1)) the ranges were 0.006 to 0.010 day(-1) and 69.3 to 115.5 days. Aerobic degradation rates for NP and NP1EO were enhanced by shaking and increased temperature, and delayed by the addition of Pb, Cd, Cu, Zn, phthalic acid esters (PAEs), and NaCl, as well as by reduced levels of ammonium, phosphate, and sulfate. Of the microorganism strains isolated from the sediment samples, we found that strain JC1 (identified as Pseudomonas sp.) expressed the best biodegrading ability. Also noted was the presence of 4'-amino-acetophenone, an intermediate product resulting from the aerobic degradation of NP by Pseudomonas sp.

Bacteria, Aerobic↗
PubMed2004

Protective effects of early treatment with propofol on endotoxin-induced acute lung injury in rats.

BACKGROUND: To investigate the effects of propofol administration on acute lung injury in endotoxin-induced shock in rats. METHODS: Seventy-six male Wistar rats were randomly assigned to one of five groups: (i) saline control; (ii) endotoxin alone (receiving lipopolysaccharide (LPS) 8 mg kg(-1) i.v.); (iii) pretreatment with propofol 1 h before LPS; (iv) simultaneous treatment with propofol and LPS; (v) post-treatment with propofol 1 h after LPS. During the 5 h after LPS injection, survival rates were recorded. Lung tissue was sampled to measure values of nitrite/nitrates (NO(2-)/NO(3-)) and tumour necrosis factor (TNF)-alpha in bronchoalveolar lavage (BAL) fluid, and wet-to-dry lung weight ratio, pulmonary permeability index, BAL protein and expression of inducible nitric oxide synthase (iNOS) and nitrotyrosine (NT). RESULTS: Compared with the endotoxaemic group, both the pre- and simultaneous treatment groups showed significantly improved 5 h survival rates, and attenuated endotoxin-induced increased BAL fluid NO(2-) /NO(3-) and TNF-alpha, iNOS mRNA and NT expression in lung tissue, and decreased pulmonary microvascular permeability. These beneficial effects were blunted in the post-treatment group. CONCLUSIONS: These findings indicate that early administration of propofol may provide protective effects against endotoxin-induced acute lung injury.

Anesthetics, Intravenous↗
PubMed2002

Anaerobic biodegradation of polycyclic aromatic hydrocarbon in soil.

Known concentrations of phenanthrene, pyrene, anthracene, fluorene and acenapthene were added to soil samples to investigate the anaerobic degradation potential of polycyclic aromatic hydrocarbon (PAH). Consortia-treated river sediments taken from known sites of long-term pollution were added as inoculum. Mixtures of soil, consortia, and PAH (individually or combined) were amended with nutrients and batch incubated. High-to-low degradation rates for both soil types were phenanthrene > pyrene > anthracene > fluorene > acenaphthene. Degradation rates were faster in Taida soil than in Guishan soil. Faster individual PAH degradation rates were also observed in cultures containing a mixture of PAH substrates compared to the presence of a single substrate. Optimal incubation conditions were noted as pH 8.0 and 30 degrees C. Degradation was enhanced for PAH by the addition of acetate, lactate, or pyruvate. The addition of municipal sewage or oil refinery sludge to the soil samples stimulated PAH degradation. Biodegradation was also measured under three anaerobic conditions; results show the high-to-low order of biodegradation rates to be sulfate-reducing conditions > methanogenic conditions > nitrate-reducing conditions. The results show that sulfate-reducing bacteria, methanogen, and eubacteria are involved in the PAH degradation; sulfate-reducing bacteria constitute a major component of the PAH-adapted consortia.

Anaerobiosis↗
PubMed2002

Occurrence and microbial degradation of phthalate esters in Taiwan river sediments.

Concentrations and microbial degradation rates were measured for eight phthalate esters (PAEs) found in 14 surface water and six sediment samples taken from rivers in Taiwan. The tested PAEs were diethyl phthalate (DEP), dipropyl phthalate (DPP), di-n-butyl phthalate (DBP), diphenyl phthalate (DPhP), benzylbutyl phthalate (BBP), dihexyl phthalate (DHP), dicyclohexyl phthalate (DCP), and di-(2-ethylhexyl) phthalate (DEHP). In all samples, concentrations of DEHP and DBP were found to be higher than the other six PAEs. DEHP concentrations in the water and sediment samples ranged from ND to 18.5 microg/l and 0.5 to 23.9 microg/g, respectively; for DBP the concentration ranges were 1.0-13.5 microg/l and 0.3-30.3 microg/g, respectively. Concentrations of DHP, BBP, DCP and DPhP were below detection limits. Under aerobic conditions, average degradation half-lives for DEP, DPP, DBP, DPhP, BBP, DHP, DCP and DEHP were measured as 2.5, 2.8, 2.9, 2.6, 3.1, 9.7, 11.1 and 14.8 days, respectively; under anaerobic conditions, respective average half-lives were measured as 33.6, 25.7, 14.4, 14.6, 19.3, 24.1, 26.4 and 34.7 days. In other words, under aerobic conditions we found that DEP, DPP, DBP, DPhP and BBP were easily degraded, but DEHP was difficult to degrade; under anaerobic conditions, DBP, DPhP and BBP were easily degraded, but DEP and DEHP were difficult to degrade. Aerobic degradation rates were up to 10 times faster than anaerobic degradation rates.

Bacteria, Anaerobic↗
PubMed2002

Ventral burn in rats: an experimental model for intravital microscopic study of microcirculation.

A novel technique of application of controlled ventral scald burn to rodent, whose back is inaccessible because of preburn preparation, is described. Boiling water is applied across a polyethylene membrane that partially envelops the subject. The technique is simple, economical, reproducible and allows intravital microscopic study of microcirculation in a remote muscular bed before and after burn injury.

Abdominal Injuries↗
PubMed2001

Biodegradation of phenanthrene in river sediment.

The aerobic biodegradation potential of phenanthrene (a polycyclic aromatic hydrocarbon [PAH]) in river sediment was investigated in the laboratory. Biodegradation rate constants (k1) and half-lives (t1/2) for phenanthrene (5 microg/g) in sediment samples collected at five sites along the Keelung River in densely populated northern Taiwan ranged from 0.12 to 1.13 l/day and 0.61 to 5.78 day, respectively. Higher biodegradation rate constants were noted in the absence of sediment. Two of the sediment samples were capable of biodegrading phenanthrene at initial concentrations 5-100 microg/g; lower biodegradation rates occurred at higher concentrations. Optimal biodegradation conditions were determined as 30 degreesC and pH 7.0. Biodegradation was not significantly influenced by the addition of such carbon sources as acetate, pyruvate, and yeast extract, but was significantly influenced by the addition of ammonium, sulfate, and phosphate. Results show that anthracene, fluorene, and pyrene biodegradation was enhanced by the presence of phenanthrene, but that phenanthrene treatment did not induce benzo[a]pyrene biodegradation during a 12-day incubation period.

Adsorption↗
PubMed2001

Microbial dechlorination of three PCB congeners in river sediment.

We investigated the potential for the anaerobic degradation of three PCB congeners (2,3,5,6-CB, 2,3,4,5-CB, and 2,3,4,5,6-CB) in sediments collected from five monitoring sites along the Keelung River in northern Taiwan. Optimal conditions for congener dechlorination were 30 degrees C and pH 7.0. Intermediate 2,3,4,5-CB products were identified as 2,3,5-CB, 2,4,5-CB, and 2,5-CB. Intermediate 2,3,4,5,6-CB products were identified as 2,3,5,6-CB, 2,3,6-CB, and 2,5-CB. For 2,3,5,6-CB, intermediate products were identified as 2,3,6-CB and 2,5-CB. Dechlorination rates for PCB congeners were observed as (fastest to slowest): 2, 3, 4-CB > 2, 3, 4, 5-CB > 2, 3, 4, 5, 6-CB > 2, 3, 5, 6-CB > 2, 2', 3, 3', 4, 4'-CB > 2, 2', 4, 4' 6, 6'-CB > 2, 2', 3, 4, 4', 5, 5'-CB > 2, 2', 3, 3', 4, 4', 5, 5'-CB. Rates decreased for mixtures of the eight congeners. Dechlorination rates for the three primary congeners under different reducing conditions occurred in the order of (fastest to slowest): methanogenic condition > sulfate-reducing condition > nitrate-reducing condition. Under methanogenic and sulfate-reducing conditions, dechlorination rates were enhanced by the addition of lactate, pyruvate, or acetate, but delayed by the addition of manganese oxide, or ferric chloride. Under nitrate-reducing condition, dechlorination rates were delayed by the addition of lactate, pyruvate, acetate, manganese oxide or ferric chloride. Treatment with such microbial inhibitors as bromoethanesulfonic acid (BESA) or molybdate revealed that methanogen and sulfate-reducing bacteria were involved in the dechlorination of these three PCB congeners.

Bacteria, Anaerobic↗