The ratio of reduced glutathione/oxidized glutathione is maintained in the liver during short-term hepatic hypoxia

Controversy persists as to whether reperfusion-induced injuries actually occur in the hepatocyte. The liver is the major source of glutathione, a scavenger of hydrogen peroxide. The aim of this study was to evaluate the sensitivity of the ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG) [GSH:GSSG] as an index of hepatic metabolic stress. A total of 121 rats were studied. The superior mesenteric vein (SMV) was occluded for 30 min, and this was followed by 0, 10, or 120 min of reperfusion. Total glutathione and GSSG levels in the liver, bile, and plasma were quantified, using glutathione reductase-coupled enzymatic assays. Results indicated that the hepatic GSH/GSSG ratio was maintained after an occlusion of the SMV, despite a decrease in adenosine triphosphate (ATP) level and energy charge potential. However, plasma levels of total glutathione and GSSG in the inferior vena cava increased after SMV occlusion and continued to increase after reperfusion. Biliary GSSG efflux decreased during 30-min occlusion of the SMV, and remained low even after reperfusion. The liver maintains homeostasis despite a decrease in biliary GSSG efflux, probably by secreting excess GSSG into the hepatic vein when the SMV is occluded. We conclude that the total amount of glutathione and GSSG in the plasma is directly correlated with oxidative stress in the liver.     

纤维素在近临界水中连续分解的研究

1 INTRODUCTIONBiomass continues to be an important candidate asa renewable resource for energy chemicals,and feed-stock.This makes cellulose,which is the major com-ponent of biomass,an important compound to study.Near-critical water (NCW) is usually referredto hot compressed water in the range of 250--350℃,which has changing properties as temperature goes upsubstantially. NCW has a strong tendency to ionizeand can act as an effective acid and base catalysts.     

Experimental verification of frequency decoupling effect on acceleration sensitivity in tuning fork gyroscopes using in-plane coupled resonators

The effect of in- and anti-phase mode decoupling on the frequency response of coupled in-plane resonators was examined, experimentally, to suppress the acceleration sensitivity (acceleration output) in tuning fork gyroscopes (TFGs). Finite element simulations, conducted in our recent works, show that the origin of acceleration sensitivity for the sensing resonators in TFGs lies in the transduction of linear (in-phase) acceleration to anti-phase resonant vibration of the sensing resonators in TFGs. We further revealed that the frequency decoupling of the in- and anti-phase vibration modes is effective in suppressing the transduction. To experimentally validate this, two types of coupled resonators (one coupled with a frame and the other with a spring) to represent the sensing resonators of TFGs were fabricated on silicon-on-insulator wafer. Different resonant frequencies were used to evaluate the frequency decoupling effect on the coupled resonators, i.e., the coupling from in-phase mode oscillation to the anti-phase mode vibration. The vibration amplitude of the anti-phase mode increased in the coupled resonators with small frequency decoupling (decoupling ratio, DR) value. Additionally, the two types of coupled resonators exhibit similar output after considering the effect of decoupling ratio, anti-phase frequency and different stiffness unbalances. Our results reveal that TFG can be designed with lower acceleration sensitivity by utilizing sense resonators with large decoupling ratio, higher anti-phase frequency, and possessing structures which are insensitive to fabrication imperfections.     

Hypocholesterolemic action of chitosans with different viscosity in rats

The relationship between hypocholesterolemic efficacy and average molecular weight of chitosan was studied in rats fed a cholesterol-enriched (0.5%) diet. Several chitosan preparations with a comparable degree of deacetylation but differing widely in average molecular weight, as demonstrated by viscosity, almost completely prevented the rise of serum cholesterol at the 5% dietary level. At the 2% level, chitosans with viscosities at both extremes exerted a comparable cholesterol-lowering action. The glucosamine oligomer composed mainly of three to five aminosugar residues was not effective. The results indicate that the hypocholesterolemic action of chitosans is independent of their molecular weight within the tested viscosity range.     

Estimation of Hydraulic Property of an Unconfined Aquifer by GPR

Controlled water productions were performed at a water source area of Ulaanbaatar city, Mongolia to evaluate the effectiveness of ground penetrating radar (GPR) for detecting and monitoring dynamic groundwater movements in the subsurface and for estimating the hydraulic properties of the aquifer. Field experiments in Ulaanbaatar were carried out in 2001 and 2002. GPR data were acquired using 100 MHz antennas. This paper reports the results of GPR methods to monitor the groundwater migration caused by the pumping operation and GPR’s potential ability to estimate hydraulic properties of the aquifer. The GPR data sets were acquired very carefully by locating the antenna position accurately. The residual trace shows a feature that is a combination of the water level reflections acquired at two different times in the pumping test. It helped to determine travel time and its effective reflection point from the top of the water saturated zone. The residual wavelet varies versus offset from the pumping well for a given residual image. Common midpoint (CMP) data and velocity analysis indicated the depth of the water table and the water content in the unsaturated and saturated zone. Combining hydrogeologic data with quantitative information yielded by GPR data, hydraulic properties of the aquifer could be estimated by assuming a hydraulic model. It was concluded that GPR can be successfully employed to monitor groundwater migration and to estimate hydraulic properties of the aquifer.     

Dispersion Behavior of Barium Titanate Nanoparticles Prepared by Using Various Polycarboxylic Dispersants

The effects of the polycarboxylic dispersant structures on the crystallinity and sedimentation behavior of prepared BaTiO₃ nanoparticles were analyzed using four types of dispersants—ethylenediaminetetraacetic acid dipotassium salt (EDTA), trans -aconitic acid (TAA), ammonium acrylate–methyl acrylate co-polymer (PAA50), and sodium polyacrylate (PAA100). In the case of EDTA and TAA, the adsorbed ratio of the dispersants on BaTiO₃ nanoparticles was relatively low, and only slight improvement of sedimentation behavior was observed. On the other hand, in the case of PAA50 and PAA100, the adsorbed ratio was high, and the sedimentation behavior was gratefully improved. Next, in order to analyze the relationships among the additive amount of polycarboxylic dispersants, crystallinity, and sedimentation behavior, various amounts of PAA100 or PAA50 were treated in the synthesis solution. The sedimentation behavior of BaTiO₃ nanoparticles improved with increasing amounts of PAA100 and PAA50 while their crystal phase became amorphous. Adding PAA50 at a molar ratio of COO⁻/Ba²⁺=0.266 resulted in BaTiO₃ nanoparticles with the best dispersion stability in an aqueous media.     

Dietary conjugated linoleic acid reciprocally modifies ketogenesis and lipid secretion by the rat liver

The effects of dietary conjugated linoleic acid (CLA) and linoleic acid (LA) on ketone body production and lipid secretion were compared in isolated perfused rat liver. After feeding the 1% CLA diet for 2 wk, the concentration of post-perfused liver cholesterol was significantly reduced by CLA feeding, whereas that of triacylglycerol remained unchanged. Livers from CLA-fed rats produced significantly more ketone bodies; and the ratio of β-hydroxybutyrate to acetoacetate, an index of mitochondrial redox potential, tended to be consistently higher in the liver perfusate. Conversely, cumulative secretions of triacylglycerol and cholesterol were consistently lower in the livers of rats fed CLA, and the reduction in the latter was statistically significant. Thus dietary CLA appeared to exert its hypolipidemic effect at least in part through an enhanced β-oxidation of fatty acids at the expense of esterification of fatty acid in the liver.     

ALOS/PALSAR full polarimetric observations of the Iwate–Miyagi Nairiku earthquake of 2008

We analysed Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) data on the areas damaged by the Iwate–Miyagi Nairiku earthquake that struck Japan in 2008. The observations before and after the earthquake have been carried out in the full polarimetric mode. We observed the dominance of surface scattering of the three-component scattering model in the landslide areas and identified 11 of the 13 landslide areas. However, we also detected vacant pieces of land, pastures and other land bodies. The possible landslide areas are estimated for 102 patch areas, of which 36 correspond to the actual landslide areas. This method is useful to detect the landslide area when the land classification map or optical image taken before a disaster is available. We propose the use of σ⁰ _VH information to distinguish the landslide areas from the other areas. Since σ⁰ _VH is sensitive to the surface roughness of an area, vacant pieces of land and pastures, which have a relatively low surface roughness, can be distinguished from the landslide areas, which have a high surface roughness. By combining the surface scattering and the σ⁰ _VH filter, the number of possible landslide areas is reduced from 102 to 54, which include the actual landslide areas except for some small patch areas.