Biomedical subjects

Dapeng Liu

Publications and source records attributed to Dapeng Liu.

3 recordsLinked to original sources

PubMed2006

Hydrogen and methane production from household solid waste in the two-stage fermentation process.

A two-stage process combined hydrogen and methane production from household solid waste was demonstrated working successfully. The yield of 43 mL H(2)/g volatile solid (VS) added was generated in the first hydrogen production stage and the methane production in the second stage was 500 mL CH(4)/g VS added. This figure was 21% higher than the methane yield from the one-stage process, which was run as control. Sparging of the hydrogen reactor with methane gas resulted in doubling of the hydrogen production. pH was observed as a key factor affecting fermentation pathway in hydrogen production stage. The optimum pH range for hydrogen production in this system was in the range from 5 to 5.5. The short hydraulic retention time (2 days) applied in the first stage was enough to separate acidogenesis from methanogenesis. No additional control for preventing methanogenesis in the first stage was necessary. Furthermore, this study also provided direct evidence in the dynamic fermentation process that, hydrogen production increase was reflected by acetate to butyrate ratio increase in liquid phase.

Acetates↗

PubMed2006

Factors influencing the prevalence of gallstones in liver cirrhosis.

BACKGROUND AND AIMS: To investigate the prevalence of gallstone disease in Chinese patients with liver cirrhosis and to identify risk factors for cholelithiasis. METHODS: Blood samples were tested and ultrasonographic examination of the upper abdomen was conducted to observe the prevalence of gallstones in 90 compensated cirrhotic patients (Child-Pugh A), 180 decompensated cirrhotic patients (Child-Pugh B, C) and 300 controls. Risk factors for gallstone formation (age, sex, pregnancy, family history) and the characteristics of liver cirrhosis (Child class, inside diameter of portal vein), and gallbladder (wall thickness) were assessed. RESULTS: Gallstones were found more often in cirrhotic patients (23.7%) than in controls (7.33%, P < 0.001). The prevalence of gallstones in decompensated cirrhotic patients was higher than that of the compensated cirrhotic patients (P < 0.001). Advanced age, female sex, family history of gallstones, gallbladder wall thickness 4 mm or greater and inside diameter of portal vein 13 mm or greater were significantly associated with gallstone disease in patients with liver cirrhosis. Multivariate analysis revealed that age (P < 0.001), sex (P = 0.0005) and thickness (4 mm or greater) of the gallbladder wall (P = 0.0064) were independently associated with gallstone disease in such patients. CONCLUSIONS: This study confirms the high prevalence of cholelithiasis in liver cirrhosis. Age and sex are risk factors for gallstones and gallbladder wall thickness could be an additional risk factor for the development of gallstone in patients with liver cirrhosis.

Abdomen↗

PubMed2005

[An experimental study on repairing bone defect with the biodegradable polycaprolactone material].

OBJECTIVE: To investigate the ability of the biodegradable polycaprolactone (PCL) material to repair bone defect and to evaluate the feasibility of using the PCL as the scaffold in tissue engineering bone. METHODS: The bone defect models of 4. 5 mm x 12 mm were made in the bilateral femoral condyle of 65 New Zealand white rabbits. The PCL cylinder was implanted into the right side of defect (experimental group, n = 60), the high dense hydroxyapatite was implanted into the left side of defect (control group, n = 60), and the incision was sutured without any implants (blank group, n = 5). The samples were harvested and observed by examinations of gross, X-ray, bone density, 99mTc-MDP bone scanning, gamma-display ratio and scanning electron microscope (SEM) after 3, 6, 9 and 12 months of operation. The results were compared between the experimental group and control group. RESULTS: At 3, 6, 9 and 12 months after operation, the gross and X-ray examinations indicated that the bone defect filled with the new bone on the PCL-tissue surface, and no delayed inflammatory reaction appeared. The average bone mineral density was greater in the experimental group than that in the control group, and the difference had statistical significance (P< 0. 05). The results of 99mTc-MDP bone scanning and gamma-display ratio showed that the nuclide uptake was more in the PCL group than that in the control group. The SEM result proved that the new compact bone formed on the PCL migrating surface as the PCL degraded gradually,but the collagen fiber sheath formed around the hydroxyapatite in the control group. CONCLUSION: PCL possesses good biocompatibility and high bone inductive potentiality, it can be used to repair bone defect.

Absorbable Implants↗