Role of platelet-activating factor and prostanoids in hemodynamic changes in rat experimental endotoxic shock

BACKGROUND: Gliadin amino acid sequence(s) responsible for toxicity in susceptible individuals have not been fully elucidated. Previous in vitro studies have suggested the presence of active sequences in the NH(2)-terminal part of the A-gliadin molecule. In this paper the in vitro activity of A-gliadin synthetic peptides 31-55, 31-43, and 44-55 has been investigated. METHODS: Organ culture of jejunal mucosa from untreated and treated coeliac patients was used. In the first system enterocyte height was used as a measure of peptide toxicity; in the second system evidence of activated mucosal cell-mediated immune response was sought. RESULTS: Peptides 31-55 and 31-43 were active on untreated coeliac mucosa at a concentration of 0.5 mg/ml and peptide 44-55 only at a concentration of 3 mg/ml. In in vitro-cultured treated coeliac mucosa peptides 31-55 and 31-43 at 1 mg/ml and peptide 44-55 at 3 mg/ml were able to induce enhanced epithelial expression of HLA-DR and 4F2 molecules and the appearance of CD25 positive cells. CONCLUSIONS: Our results suggest that 31-43 and 44-55 A-gliadin peptides are both active, even if to different extents. In vitro systems remain essential tools to screen material to be subsequently tested in vivo.     

SiC晶须砂轮的开发及其磨削特性

细磨粒砂轮用来进行高精度磨削。然而，由于细磨粒具有较小的结合面积，即使在正常的磨削条件下，磨粒易于从砂轮表面上脱落，导致加工精度与效率低下。近十年来，由于SiC晶须(微细纤维)具有高硬度、高强度、高耐磨性和相容性好等优良的机械与物理化学特性，因而广泛地用作金属、陶瓷、塑料及复合材料的强化材料^[1-2]。SiC晶须的平均长度和直径分别为50μm左右和数微米，比相同直径的细磨粒具有相对较大的结合面积。1993年以来，日本山口胜美、洞口严教授和中国魏源迁教授使用SiC晶须作为磨料和酚醛树脂结合剂，成功地开发了一种SiC晶须砂轮^[3-5]。该砂轮中的SiC晶须按同一方向排列且与砂轮磨削面相垂直，晶须的端部可作为切削刃。为了考察此砂轮的磨削特性，本文对难加工材料如模具钢SKD11(HRC60))进行了大量的磨削试验。试验结果表明该砂轮不仅具有很高的磨削比(6000以上)和磨削效率，而且能获得纳米级加工表面(Ral．5nm／Ry16nm)。     

Solution‐processed organic TFT array for active‐matrix LCDs on a plastic substrate

Abstract— Organic TFTs (OTFTs) have been developed with a novel solution‐processed gate insulator of poly(4‐vinylphenol) (PVP) with the addition of octadecyltrichloro‐silane (OTS) and a solution‐processed organo‐silver electrode/wire to improve the performance of an OTFT and to maked high‐throughput‐manufacturing process possible. Solution‐processed PVP has also employed for a buffer layer on a plastic substrate. The OTFT backplane with these solution‐based organic‐material technologies has been successfully applied to drive a 2.5‐in. QQVGA (160 × 120 pixels) AMLCD with a resolution of 79 dpi.     

Multilayer optical thin films for use at terahertz frequencies: method of fabrication

A new method of fabricating multilayer optical coatings used at terahertz frequencies has been developed. Using plasma-enhanced chemical-vapor deposition, a multilayer antireflection coating for germanium optics at terahertz frequencies was fabricated. The coating consists of amorphous silicon and silicon-oxide layers. The transmittance and structure of the coating were experimentally investigated. The transmittance spectrum of the coating on the Ge substrate shows a wideband antireflection behavior in the 40-120 cm(-1) region.     

Prostaglandins and renin release in vitro

The present studies were undertaken to explore further the role of prostaglandins in the release of renin from the renal cortex. To provide the best assessment of renin release, renin was determined by a radioimmunoassay for the direct measurement of renin. Slices of mouse renal cortex were incubated at 37 degrees C with arachidonic acid (AA), 5,8,11,14-eicosatetraenoic acid (ETA), indomethacin, prostaglandins, and synthetic prostaglandin endoperoxide analogue (EPA). Our results showed that AA at 1.5 X 10(-8) M significantly increased renin release at 10 and 30 min of incubation. This renin increase ws abolished by either ETA or indomethacin. Prostaglandin F2 alpha (PGF2 alpha) also significantly stimulated renin release at 10 and 60 min. PGE2 and 16,16-dimethyl PGE2 (DMPGE2) showed much less renin release-stimulating activity. EPA and PGI2 on the other hand very strongly stimulated renin release. However, at higher concentrations the stimulating effect of PGI2 and EPA disappeared and even became inhibitory in the case of EPA. Other prostaglandins were found to have no effect on renin release. The results suggest that the prostaglandin system directly affects renin release from the juxtaglomerular cells independent of systemic neurogenic and hemodynamic influences.     

Normalised frequency dependence of splice losses in single-mode optical fibres

Simple formulas for splice losses have been derived by using the series expansion. The losses are proportional to the square of normalised axial or angular displacement. The coefficient is determined by only the normalised frequency. Normalised frequency dependence measurements of the splice losses show excellent agreement with the theory.     

Mechanism of glass formation in portland cement clinker

In the system C₃A---C₄AF---SiO₂---MgO, the glass formation region that is closely similar in composition to the interstitial material of portland cement clinker has been determined. The interstitial melt that exists in equilibrium with the silicates at the clinkering temperature contains a little silica. This forms clusters, which increase the viscosity of the melt and cause the latter to supercool appreciably. Crystallization of C₃A and C₄AF increases the concentration of clusters, which progressively interlock in the residual liquid, thus giving a glass on quenching. The presence of SiO₂ in the interstitial melt also enables the metastable formation of the orthorhombic aluminate and the oriented overgrowth of the ferrite on the aluminate to occur through encouraging supercooling of the melt.     

Very low OH content P2O5-doped silica fibres

Very low OH content optical fibres consisting of P2O5-doped silica core and GeO2-P2O5-B2O3-doped silica cladding were fabricated by the m.c.v.d. technique. The relation between the OH absorption loss and the deposition temperature was clarified. The OH content in this fibre could be reduced to about seven parts per billion (~ 7 × 10?9) by using a low deposition temperature.