Biomedical subjects

Yao Shi

Publications and source records attributed to Yao Shi.

24 records · Page 2Linked to original sources

PubMed2004

[Scale-up study on pulse corona discharge for the removal of toluene].

The scale-up experiments of the decomposition of toluene by pulse corona discharge in wire-plate reactor were investigated. The maximum output power of pulse voltage source was 1 kW, and the maximal peak voltage was 100 kV. The experiments were conducted with a gas-flow rate of 4-16 m3 x h(-1). Different parameters which influenced on removal efficiency were investigated, such as peak voltage, pulse frequency, inlet concentration of toluene, gas-flow rate. The results showed that the removal efficiency was improved obviously when the peak field intensity was changed in the range of 9-12 kV x cm(-1); the removal efficiency 88% was obtained when gas-flow rate, peak voltage, inlet concentration of toluene, pulse frequency were 4 m3 x h(-1), 69 kV, 1180 mg x m(-3), 300 pps respectively. The energy yield of toluene was about 16 g x (kW x h)(-1); the main products of decomposition were CO2 and H2O, few of CO. Combining the removal efficiency of toluene with energy density and inlet concentration of toluene, a reaction kinetic mathematic model was developed. By this model, the decomposition rate constant of toluene was 0.00356 L x J(-1). According to the results, the optimization design for the reactor and the matching of pulse voltage source were reckoned.

Air Pollutants↗

PubMed2004

[Properties of Pesudomonas sp. DN-1 in reduction of nitric oxide chelate absorption solution].

Metal chelate absorption is deemed as a promising method of NO removal in FGD system, but the difficulty in the regeneration of the absorption solution hinders its further development. An original method with microbial reduction is proposed in this paper. With the adding of Psudomonas sp. DN-1, which was newly isolated from wastewater treatment plant, FeII (EDTA) NO will be reduced to the environmentally benign gaseous product of N2, and thus FeII (EDTA) was regenerated simultaneously. The effects of the types and amount of carbon source, FeII (EDTA) NO concentration, pH, temperature and the biomass inoculation on bio-reduction efficiency were investigated. The results showed that the microorganism exhibited good performance on bio-reduction of FeII (EDTA) NO with the carbon sources of glucose. 250 mg x L(-1) glucose was enough for microorganism to reduce 6.50 mmol x L(-1) FeII (EDTA) NO completely. The rate of FeII (EDTA) NO reduction did not increase with adding a larger amount of carbon source. The bio-reduction could be achieved efficiently among the temperature range of 40 - 45 degrees C and a pH range of 6.9 - 7.2. The bio-reduction rate increased with the increasing of biomass inoculation. When FeII (EDTA) NO concentration is less than 11.8 mmol x L(-1), the reduction rate increased as the concentration increases, while the concentration is over 11.8 mmol x L(-1), the reduction rate keeps constant.

Absorption↗

PubMed2004

Desulfurization of dibenzothiophene by a newly isolated Corynebacterium sp. ZD-1 in aqueous phase.

Sulfur emission through fuel combustion is a global problem because it is a major cause of acid rain. Crud oil contains many heterocyclic organic sulfur compounds, among which dibenzothiophene (DBT) and DBTs bearing alkyl substitutions usually are representative compounds. A strain was isolated from refinery sludge and identified as Corynebacterium ZD-1. The behavior of DBT degradation by ZD-1 in aqueous phase was investigated. Corynebacterium ZD-1 could metabolize DBT to 2-hydroxybiphenyl(2-HBP) as the dead-end metabolite through a sulfur-specific pathway. In shake flask culture, ZD-1 had its maximal desulfurization activity in the late exponential growth phase and the specific production rate of 2-HBP was about 0.14 (mmol x kg dry cell(-1) x min(-1), mmol x KDC(-1) x min(-1)). Active resting cells for desulfurization should be prepared only in this period. 2-HBP inhibited the growth of strain ZD-1, the production of DBT degradation enzymes, and the activity of enzymes. Sulfate inhibited the production of dibenzothiophene (DBT) degradation enzymes but had no effect on the enzymes' activity. The production rates of 2-HBP at lower cell densities were higher and the maximum amount conversion of DBT to 2-HBP (0.067 mmol/L) after 8 h was gained at 9.2 g dry cell/L rather higher cell density. The results indicated that this newly isolated strain could be a promising biocatalyst for DBT desulfurization.

Air Pollution↗

PubMed2003

The effect of folic acid on the development of stomach and other gastrointestinal cancers.

OBJECTIVE: To evaluate the roles of folic acid and beta-carotene in the chemoprevention of gastric and other gastrointestinal (GI) cancers. METHODS: In a randomized, double-blind, placebo-controlled trial, a total of 216 patients with atrophic gastritis were randomly assigned to one of the four groups: (1) folate (FA, 20 mg per day plus vitamin B(12) 1 mg, intramuscularly, per month for one year, then 20 mg two times a week plus 1 mg per three months for the next year); (2) natural beta-carotene (N-betaC, 30 mg per day for first year, then 30 mg two times a week for the next); (3) synthetic beta-carotene (S-betaC, administered as in N-betaC); and (4) placebo. Follow-ups continued from 1994 to 2001. RESULTS: A total of 7 new cases of gastrointestinal cancers were diagnosed with 3 stomach, 1 colon and 1 esophageal cancers occurring in the placebo group; 1 stomach cancer in both of the N-betaC and S-betaC groups, and no cancer occurring in FA group. In terms of GI cancers, there was a significant reduction in the FA group, compared with the placebo group (P = 0.04). A similar trend was observed in both N-betaC and S-betaC groups (P = 0.07 - 0.08). Taken together, the three intervention groups displayed a highly significant decrease in occurrence (P = 0.004, vs placebo), and a lower risk for GI cancers (OR = 0.12; 95% confidence interval, 0.03 - 0.51). For development of gastric cancer, any one of the three active-treated groups did not reach statistically significant reduction. The FA group showed obvious improvement of the gastric mucosal lesions with more patients displaying lesions reversed or stable atrophy and inflammation (P = 0.04), reversed intestinal metaplasia (P = 0.06) at the end of follow-up, and reversed displasia (P = 0.017) at 12 months. Two cases of false jaundice were found in beta-carotene groups with no influence on administration, and no side-effects were reported in FA group. CONCLUSIONS: This trial revealed the interventional effect of folic acid on the development of GI cancers, a similar effect of beta-carotene was also detected. Also, folic acid may be of use to treat atrophic gastritis by preventing or reversing the precancerous lesions.

Adult↗

PubMed2002

Capture and separation of CO2 from flue gas by coupling free and immobilized amines.

A novel system was proposed for the capture and separation of CO2 from flue gas. In this method, a resin was employed to regenerate the amine capturing CO2 from flue gas at room temperature. The feasibility for the resin to regenerate amines such as MEA, MAE, TEA, and ammonia was demonstrated. It was also discovered that the resin could be regenerated by hot water.

Adsorption↗

PubMed1998

Effect of Helicobacter pylori infection on gastric epithelial proliferation in progression from normal mucosa to gastriccarcinoma.

AIM:To study the effect of Helicobacter pylori (H. pylori) infection on gastric epithelial proliferation in the progression from normal mucosa to gastric carcinoma.METHODS:Gastric biopsy specimens from normal controls (n = 11), superficial gastritis (n = 32), atrophic gastritis with intestinal metaplasia (n= 83), dysplasia (n= 25) and gastric carcinoma (n = 10) were studied by immunohistochemical stianing of proliferating cell nuclear antigen (PCNA).RESULTS: The gastric epithelial proliferation, expressed as PCNA labeling index (LI)%, was progressively increased in successive stages from normal mucosa to gastric carcinoma regardless of H. pylori status. There was significant difference in PCNA LI% among all groups (P <0.01). The analysis pursuing the effect of H. pylori infection on gastric epithelial proliferation in the progression from normal mucosa to gastriccarcinoma showed that in superficial gastritis and mild atrophic gastritis groups, PCNA LI% in H. pylori positive patients were 13.14 ± 1.6 and 19.68 ± 2.22 respectively, significantly higher than 6.95 ± 0.78 and 11.34 ± 1.89 in H. pylori negative patients (P <0.01); but there was no such difference in other groups (P >0.05).CONCLUSION:H. pylori infection causes increased gastric epithelial proliferation in the stages of superficial and mild atrophic gastritis and may play a part in triggering gastric carcinogenesis.

Journal Article↗