Modulation of contact system proteases by glycosaminoglycans. Selective enhancement of the inhibition of factor XIa

We investigated the influence of dextran sulfate, heparin, heparan sulfate, and dermatan sulfate on the inhibition of FXIa (where FXIa is activated factor XI, for example), FXIIa, and kallikrein by C1 inhibitor, alpha1-antitrypsin, alpha2-antiplasmin, and antithrombin III. The second-order rate constants for the inhibition of FXIa by C1 inhibitor, alpha1-antitrypsin, alpha2-antiplasmin, and antithrombin III, in the absence of glycosaminoglycans, were 1.8, 0.1, 0.43, and 0.32 x 10(3) M-1 s-1, respectively. The rate constants of the inactivation of FXIa by C1 inhibitor and by antithrombin III increased up to 117-fold in the presence of glycosaminoglycans. These data predicted that considering the plasma concentration of the inhibitors, C1 inhibitor would be the main inhibitor of FXIa in plasma in the presence of glycosaminoglycans. Results of experiments in which the formation of complexes between serine protease inhibitors and FXIa was studied in plasma agreed with this prediction. Glycosaminoglycans did not enhance the inhibition of alpha-FXIIa, beta-FXIIa, or kallikrein by C1 inhibitor. Thus, physiological glycosaminoglycans selectively enhance inhibition of FXIa without affecting the activity of FXIIa and kallikrein, suggesting that glycosaminoglycans may modulate the biological effects of contact activation, by inhibiting intrinsic coagulation without affecting the fibrinolytic potential of FXIIa/kallikrein.     

Characterization and Identification of Triglycerides by Infrared Spectroscopy

Infrared spectroscopy can be a more powerful tool for fat analysis as is generally thought. Infrared spectra of solid triglycerides, unlike spectra of fats in the liquid form or in solutions, can namely give information about the following items: crystallization form, chain length of the fatty acid moieties, isomeric form, unsaturated fatty acid moieties, cis or trans unsaturation, and position of double bonds. This is illustrated by some examples. Almost all bands have been assigned, even in the fingerprint region. To understand the observed phenomena, the new concept ‘diathesis’ has been used with success.     

The influence of a barrel-valve on the degree of fill in a co-rotating twin-screw extruder

The influence of a barrel-valve on the degree of fill of a co-rotating, twin-screw extruder (MPF-50) built by APV Baker was measured by opening the barrel and by residence time distribution (RTD) measurements. The RTDs, which were measured by a radio tracer technique, were characterised by their minimum and average residence times and curve widths. Measurements were made at a ‘low’ and a ‘high’ barrel temperature profile, two mass flows and three screw speeds. The degree of fill and the minimum and average residence time increased when the valve in the barrel was closed. When the rotational speed of the screw decreased the hold-up in the extruder increased. The degree of fill during the measurements ranged from 30% to 56%, depending on the temperature, barrel-valve position, rotational speed of the screws and the feed rate. With a ‘low’ temperature profile the width of the curve was independent of the barrel valve position. When the barrel-valve was closed at ‘high’ temperatures, only a minor increase in the curve width, of the order of twice the measurement accuracy, was found.     

15—A NEW APPROACH TO BARRÉ-FREE PACKAGES OF CONTINUOUS-FILAMENT WEFT YARN: THE ‘MEGAPHONE’ TRAVERSE PATTERN

It has been found that barré streaks in woven fabrics, particularly those made from polyamide-fibre yarns, can be markedly reduced by the use of yarns from packages wound in a special way on the drawtwister. Graphical analysis has shown that the best results are to be expected from a ‘megaphone build-up’, so named from the shape of the traverse pattern. In building up a package with this type of pattern on the drawtwister, the length of the traverse stroke is reduced during approximately one-third of the winding time and subsequently increased again to its initial value during the remaining winding time.

Weaving tests have shown that yarn from these packages considerably reduces the barre effect compared with yarn from packages wound according to the known types of build-up.     

染料敏化太阳能电池中TiO2光阳极形貌研究进展

纳米TiO2具有合适的禁带宽度(3.2 eV)、良好的光电化学稳定性、价格低廉、易牢固吸附染料等优点,目前仍是应用于染料敏化太阳能电池(DSSC)主要的半导体材料。TiO2光阳极是DSSC的重要组成部分之一,其晶体的形貌与DSSC的光电性能密切相关。本文综述了应用于DSSC中不同形貌TiO2光阳极,重点探讨了常规TiO2光阳极形貌,如纳米粒子、纳米棒、纳米线、纳米管;对新型TiO2光阳极及复合光阳极的形貌也作了介绍。讨论了不同形貌TiO2光阳极的制备方法及其结构对DSSC光电性能的影响,提出TiO2光阳极今后的研究方向是将不同形貌光阳极进行复合或混合掺杂来提高电子传输速率、优化TiO2薄膜厚度、控制TiO2薄膜中晶体结构抑制电荷再结合、提高电荷传输效率。