Biomedical subjects

Yuan Zhou

Publications and source records attributed to Yuan Zhou.

40 records · Page 3Linked to original sources

PubMed2002

Change of vanilloid receptor 1 following neuromodulation in rats with spinal cord injury.

BACKGROUND: Neuromodulation has been used to treat voiding dysfunction caused by spinal cord injury (SCI). However, the underlying mechanism of this technique is not well understood. Recently, vanilloid receptor 1 (VR1) has been recognized as a capsaicin receptor and an agent for noxious stimuli. The purposes of this study were to evaluate whether development of bladder hyperreflexia after SCI involves VR1 upregulation and whether VR1 is involved in the process of neuromodulation. MATERIALS AND METHODS: Sprague-Dawley rats (n = 20) were divided into five groups: sham control (n = 4); 3 days after SCI (n = 4); 7 days after SCI (n = 4); 14 days after SCI (n = 4), and 14 days after SCI with neurostimulation (n = 4). Bilateral electrode wires were implanted into S1 dorsal foramina and electrical stimulation was performed 8 h/day for 2 weeks. Spinal segments of L6, S1, and dorsal root ganglia were removed and cut into sections. The intensity of VR1 staining was evaluated by image analysis. RESULTS: VR1-positive staining was confined to the superficial dorsal horn of the spinal cord. The staining was weak in the sham group (1/luminosity: 0.0050 +/- 0.0006), but the staining intensity was significantly increased in three SCI groups (3 days, 7 days, and 14 days) when compared with that in the sham group (P < 0.05). After neuromodulation, the staining intensity was reduced. CONCLUSIONS: VR1 expression in the spinal cord is up-regulated after SCI. Sacral nerve root stimulation can down-regulate the VR1 expression.

Animals↗

PubMed2002

[Determination of silicon, manganese and magnesium in cast iron by atomic emission spectrometry].

A spectrograph with high voltage spark source, once pre-burned and continuous photography was used for the quantitative determination of Silicon, Manganese and Magnesium in cast iron. The experimental conditions were optimized including the control of pre-burning time, plate moving rate, slit height of the blackness measuring, the selection of electrode material, the distance between the electrodes, shape of the electrode and the diminution of interferences. The determination range of contents (w/w) are 0.010%-0.090% for Mg, 1.50%-3.50% for Si and 0.40%-1.10% for Mn. The relative standard deviations are 10.4%, 1.9% and 3.0% for Mg, Si, and Mn, respectively.

English Abstract↗

PubMed2001

Cooperation of yeast peroxiredoxins Tsa1p and Tsa2p in the cellular defense against oxidative and nitrosative stress.

Peroxiredoxins are a family of antioxidant enzymes conserved from bacteria to humans. In Saccharomyces cerevisiae, there exist five peroxiredoxins, among which Tsa2p shares striking homology with the well described Tsa1p but has not been extensively studied. Here we report on the functional characterization of yeast tsa2Delta mutants and the comparison of TSA1 with TSA2. The tsa2Delta and tsa1Delta tsa2Delta cells grew normally under aerobic conditions. However, the tsa1Delta tsa2Delta mutant yeast was more susceptible to oxidants than either tsa1Delta or tsa2Delta cells. Notably, the tsa1Delta tsa2Delta yeast was also hypersensitive to peroxynitrite and sodium nitroprusside. This phenotype was rescued by the expression of either the TSA1 or TSA2 gene. The demonstration of a peroxynitrite reductase activity of Tsa2p in vitro points to a pivotal role for peroxiredoxins in the protection against nitrosative stress. In yeast cells, Tsa1p and Tsa2p exhibited comparable antioxidant activity. While the basal expression level of TSA1 was significantly higher than that of TSA2, the transcription of TSA2 was stimulated more potently by various oxidants. In addition, TSA2 was activated in tsa1Delta cells in a Yap1p-dependent manner. Taken together, our findings implicate the cooperation of Tsa1p and Tsa2p in the cellular defense against reactive oxygen and nitrogen species.

Blotting, Northern↗

PubMedDate not supplied

Interactive point-based rendering of higher-order tetrahedral data.

Computational simulations frequently generate solutions defined over very large tetrahedral volume meshes containing many millions of elements. Furthermore, such solutions may often be expressed using non-linear basis functions. Certain solution techniques, such as discontinuous Galerkin methods, may even produce non-conforming meshes. Such data is difficult to visualize interactively, as it is far too large to fit in memory and many common data reduction techniques, such as mesh simplification, cannot be applied to non-conforming meshes. We introduce a point-based visualization system for interactive rendering of large, potentially non-conforming, tetrahedral meshes. We propose methods for adaptively sampling points from non-linear solution data and for decimating points at run time to fit GPU memory limits. Because these are streaming processes, memory consumption is independent of the input size. We also present an order-independent point rendering method that can efficiently render volumes on the order of 20 million tetrahedra at interactive rates.

Journal Article↗