Flood Risk Analysis Based on Information Diffusion Theory

Due to the fact that the flood data series of small drainage basins is relatively short, available data are often not sufficient for flood risk analysis. This presents the problem of risk analysis using very small data samples. One method that can be applied is to regard the available small samples as fuzzy information and optimize them using information diffusion technology to yield analytical results with greater reliability. In this article a risk analysis method based on information diffusion theory is applied to create a new flood risk analysis model. Application of the model is illustrated taking the Jinhuajiang and Qujiang drainage basins as examples. This is a new attempt at applying information diffusion theory in flood risk analysis. Computations based on this analytical flood risk model can yield an estimated flood damage value that is relatively accurate. This study indicates that the aforementioned model exhibits fairly stable analytical results, even when using a small set of sample data. The results also indicate that information diffusion technology is highly capable of extracting useful information and therefore improves system recognition accuracy. This method can be easily applied and the analytical results produced are easy to understand. Results are accurate enough to act as a guide in disaster situations.     

Transport of GABA at the Blood-CSF Interface

Abstract: The entry of GABA into cerebrospinal fluid (CSF) was studied in dogs anesthetized with pentobarbital and relaxed with suxamethonium. GABA was administered intravenously as a priming dose and subsequent maintenance infusion to compensate for the rapid elimination of the amino acid. Steady state concentrations of GABA in CSF were reached between 10 and 60 min after injection, the rate of entry tending to decrease with increasing plasma levels. During steady state conditions CSF concentrations showed great interin-dividual differences and varied between 0.03 and 5.1% of those in plasma. Probenecid and sodium valproate considerably enhanced the CSF/plasma concentration ratio of GABA. When GABA was directly injected into the liquor space, probenecid slowed down the elimination of GABA from CSF. The results suggest a transport of GABA into and out of CSF, the outward transport being inhibited by probenecid and sodium valproate.     

Ensembles of endothelial and mural cells promote angiogenesis in prenatal human brain

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Horseradish peroxidase: a reliable or a misleading tool for the investigations on the origin of the proteins of the aqueous humor?

The concept of the blood-aqueous barrier is largely based on the use of horseradish peroxidase (HRP). The present investigation was designed to check its reliability as a macromolecular tracer, especially with regard to the transport of plasma proteins. Rabbits were killed 5 min to 24 h after being intravenously injected with HRP. The tracer diffused rapidly, reaching the aqueous humor of the eye in 3 min or less and was detected at high concentration in the narrow space between the outer epithelial layer of the ciliary epithelium and the wall of the pervious capillaries in the stroma of the processes. HRP appeared to migrate from the blood to the posterior chamber, permeating the tight junctions, viz., the anatomical basis of the blood-aqueous barrier. It was detected at higher concentration at the anterior surface of the iris, at short time intervals; this was interpreted as penetration of the tracer from the aqueous humor of the anterior chamber. The choroid was also labeled in continuation with the reaction in the stroma of the pars plana of the ciliary body which, in turn, sometimes reached the iris root. Therefore, the pervious blood vessels of the choroid could be a source of macromolecules for the iris root. HRP also induced the formation of lysosomes in the ciliary epithelium. This can hardly be accepted as the way in which plasma proteins are physiologically transported to the aqueous humor. However, the pathway of HRP migration over short time intervals seems to be in agreement with previous research indicating that the entrance of serum albumin into the posterior chamber is the first step of its incorporation into the aqueous humor. Received: 7 June 1996 / Accepted: 15 January 1997     

Mannitol induces selective astroglial death in the CA1 region of the rat hippocampus following status epilepticus

In the present study, we addressed the question of whether treatment with mannitol, an osmotic diuretic, affects astrogliovascular responses to status epilepticus (SE). In saline-treated animals, astrocytes exhibited reactive astrogliosis in the CA1-3 regions 2-4 days after SE. In the mannitol-treated animals, a large astroglial empty zone was observed in the CA1 region 2 days after SE. This astroglial loss was unrelated to vasogenic edema formation. There was no difference in SE-induced neuronal loss between saline- and mannitol-treated animals. Furthermore, mannitol treatment did not affect astroglial loss and vasogenic edema formation in the dentate gyrus and the piriform cortex. These findings suggest that mannitol treatment induces selective astroglial loss in the CA1 region independent of vasogenic edema formation following SE. These findings support the hypothesis that the susceptibility of astrocytes to SE is most likely due to the distinctive heterogeneity of astrocytes independent of hemodynamics. [BMB Reports 2015; 48(9): 507-512]     

Characterization of Aspergillus niger catalase

Aspergillus niger catalase has been characterized by a variety of physical techniques including gel filtration, sedimentation rate and equilibrium methods and photon correlation spectroscopy. The catalase has a sedimentation coefficient (S₂₀⁰) of 14.2 ± 0.08 S and diffusion coefficient (D₂₀⁰) of 4.14 ± 0.35 × 10⁻⁷ cm² s⁻¹. The average molecular weight of the catalase from all available data including current sedimentation equilibrium measurements and two previous literature values is 345 000. The frictional ratio of the molecule assuming a hydration parameter similar to that of bovine liver catalase (.3 g H₂O g⁻¹) is 1.103, suggesting that Aspergillus niger catalase has an asymmetric structure with an axial ratio of approximately 3 (the Stokes radius is 5.83 ± 0.49 nm). The titration curve and amino acid analysis indicate that in the native conformation only 23% of the ionizable amino acid residues are titratable between pH 3 and 10.5. Denaturation with sodium n-dodecylsulphate increases the number of titratable groups to 46%. The ratio of anionic to cationic amino acid residues in Aspergillus niger catalase is 2.46 and the isoelectric point is 6.5. The optimum pH for catalytic activity is approximately 7.     

Depolarized fluorescence photobleaching recovery

The effects of the fact that the laser sources typically used in fluorescence photobleaching recovery (FPR) experiments in the most commonly employed in-line microscope imaging geometries, are highly linearly polarized, are examined in some detail. The implications of the results, in particular for the interpretation of FPR data in complex cell membrane systems in terms of laterally mobile and immobile sub-populations of the labelled molecular species of concern, are discussed. Methods of experimentally eliminating the potentially major rotational diffusion-based artifacts, different from those appropriate to three-dimensional (solution or suspension) systems which require other than in-line geometries, are delineated.Abbreviations FPR fluorescence photobleaching recovery - FRAP fluorescence recovery after photobleaching - 2- and 3-D two- and three-dimensional     

Chain length and pressure dependence of lipid translational diffusion

The translational diffusion of pyrene, pyrene butyric acid and pyrene decanoic acid has been determined in phosphatidylcholine bilayers of different chain length and under pressure up to 200 bars. In the liquid crystalline phase and at a given temperature the diffusion decreases with increasing chain length. At a constant reduced temperature, T _red (about 10 K above the transition temperature), long chain lipids exhibit the fastest diffusion which is in disagreement with hydrodynamic models but favours free volume models for diffusion in lipid bilayers. The volume of activation, V _act, calculated from the decrease of the diffusion coefficient with pressure, ln D/P, depends on lipid chain length. V _act decreases with decreasing lipid chain length at a given temperature, T=65°C, and increases at the reduced temperature. These results are again in agreement with the dependence of the diffusion on lipid chain length and therefore with the free volume model.Abbreviations DLPC Dilauroylphosphatidylcholine - DMPC Dimyristoylphosphatidylcholine - DPPC Dipalmitoylphosphatidylcholine - DSPC Distearoylphosphatidylcholine - LUV Large unilamellar vesicles - SUV Small unilamellar vesicles - Tris Tris(hydroxymethyl)aminomethan