Biomedical subjects

Liming Shi

Publications and source records attributed to Liming Shi.

3 recordsLinked to original sources

PubMed2005

Membrane-based wet electrostatic precipitation.

Emissions of fine particulate matter, PM2.5, in both primary and secondary form, are difficult to capture in typical dry electrostatic precipitators (ESPs). Wet (or water-based) ESPs are well suited for collection of acid aerosols and fine particulates because of greater corona power and virtually no re-entrainment. However, field disruptions because of spraying (misting) of water, formation of dry spots (channeling), and collector surface corrosion limit the applicability of current wet ESPs in the control of secondary PM2.5. Researchers at Ohio University have patented novel membrane collection surfaces to address these problems. Water-based cleaning in membrane collectors made of corrosion-resistant fibers is facilitated by capillary action between the fibers, maintaining an even distribution of water. This paper presents collection efficiency results of lab-scale and pilot-scale testing at FirstEnergy's Bruce Mansfield Plant for the membrane-based wet ESP. The data indicate that a membrane wet ESP was more effective at collecting fine particulates, acid aerosols, and oxidized mercury than the metal-plate wet ESP, even with approximately 15% less collecting area.

Air Movements↗

PubMed2004

Real time quantitative PCR as a method to evaluate xenotropic murine leukemia virus removal during pharmaceutical protein purification.

Chinese hamster ovary cells used for pharmaceutical protein production express noninfectious retrovirus-like particles. To assure the safety of pharmaceutical proteins, validation of the ability of manufacturing processes to clear retrovirus-like particles is required for product registration. Xenotropic murine leukemia virus (X-MuLV) is often used as a model virus for clearance studies. Traditionally, cell-based infectivity assay has been the standard virus quantification method. In this article, a real time quantitative PCR (Q-PCR) method has been developed for X-MuLV detection/quantification. This method provides accurate and reproducible quantification of X-MuLV particle RNA (pRNA) over a linear dynamic range of at least 100,000-fold with a quantification limit of approximately 1.5 pRNA copies microL(-1). It is about 100-fold more sensitive than the cell-based infectivity assay. High concentrations of protein and cellular DNA present in test samples have been demonstrated to have no impact on X-MuLV quantification. The X-MuLV clearance during chromatography and filtration procedures determined by this method is highly comparable with that determined by the cell-based infectivity assay. X-MuLV clearance measured by both methods showed that anion exchange chromatography (QSFF) and DV50 viral filtration are robust retroviral removal steps. In addition, combination of the two methods was able to distinguish the viral removal from inactivation by the Protein A chromatography, and fully recognize the viral clearance capacity of this step. This new method offers significant advantages over cell-based infectivity assays. It could be used to substitute cell-based infectivity assays for process validation of viral removal procedures, but not inactivation steps. Its availability should greatly facilitate and reduce the cost of viral clearance evaluations for new biologic product development.

Animals↗

PubMed2004

Effect of heme oxygenase-1 inducer hemin on chronic renal failure rats.

The role of HO-1 inducer, hemin, in chronic renal failure (CRF) rats and its possible mechanism of action was studied. 5/6 subtotal nephrectomy was performed to establish chronic renal failure model. Rats were randomly assigned to 4 groups: sham-operated group, CRF group, ferrous gluconate group and hemin group. At the 10th week after operation, serum creatinine, BUN, RBC, HGB and HCT were measured. Renal pathologic changes were observed. RT-PCR and immunohistochemistry were used to detect the expression and distribution of HO-1. RT-PCR and radioimmunoassay was used to determine the expression of ET-1 in the kidney and plasma. The results showed that as compared with CRF group, serum creatinine and BUN in hemin group were reduced significantly and nephrogenic anemia was improved markedly. Glomerular mesangial proliferation and interstitial lesion were also ameliorated significantly. Hemin not only increased the expression of HO-1 but also reduced the expression of ET-1 in the kidney. The level of ET-1 protein in the plasma was also reduced after hemin treatment. Most of these indexes were not obviously changed in ferrous gluconate group. It was suggested that through inducing the expression of HO-1 and reducing the level of ET-1 in the kidney and plasma, hemin plays an important protective role in 5/6 subtotal nephrectomized rats.

Animals↗