原油高效减阻剂的制备及其性能

采用本体聚合方法,以TiCl4/Al(Et)2Cl为催化体系,C10～C14长链α-烯烃为单体,合成了原油管输高效减阻剂,对该减阻剂的制备、后处理等工业化方法进行了探讨。对聚合物进行了FTIR、1HNMR、XRD、TG表征,对浆料进行了减阻性能测试。结果表明,该聚合物为无定型半透明弹性体,相对分子质量410×104,最初分解温度300℃。将聚合物冷冻粉碎后,可配制出质量分数为47%、凝点低于-50℃、流动性较好、难挥发的高碳醇基减阻剂浆料。当减阻剂在柴油中的质量浓度为0.01kg/m3时,减阻率可达40.1%。     

CD4-mediated inhibiton of IL-2 production in activated T cells

The role of CD4 in T cell activation has been attributed to its capacity to increase the avidity of interaction with APC and to shuttle associated Lck to the TCR/CD3 activation complex. The results presented in this study demonstrate that ligation of CD4 inhibits ongoing responses of preactivated T cells. Specifically, delayed addition of CD4-specific mAb is shown to inhibit Ag- or mAb-induced responses of both primary T cells and T cell clonal variants. The Ag responses of the latter are independent of the adhesion provided by CD4; thus the observed inhibition is not due to blocking CD4-MHC interactions. Further, analysis of the clonal variants demonstrates that CD4-associated Lck is not essential for the inhibition observed, as anti-CD4 inhibits responses of clonal variants, expressing a form of CD4 unable to associate with Lck (double cysteine-mutated CD4). The inhibition is counteracted by the addition of exogenous IL-2, demonstrating that the block is not due to a lesion in IL-2 utilization, rather its production. It is demonstrated that the delayed addition of anti-CD4 results in a rapid reduction in steady-state levels of IL-2 mRNA in both primary T cells and clonal variants.     

Stable isotope ratio analysis of amino acids: the use of N(O,S)-ethoxycarbonyl trifluoroethyl ester derivatives and gas chromatography/mass spectrometry

N(O,S)-Ethoxycarbonyl trifluoroethyl amino acid esters are formed by the reaction of amino acids with ethylchloroformate plus trifluoroethanol plus pyridine. The use of these derivatives for a rapid and sensitive determination of specific enrichment of stable isotopically labeled tracer amino acids in blood plasma and protein hydrolysates, by using gas chromatography/electron impact mass spectrometry, is discussed.     

OILWELL COMPLETION FLUID SOLIDS INTERACTION WITH AN UNCONSOLIDATED OIL RESERVOIR

This work addresses the problem of modelling, detection and evaluation of the mechanical interaction between oilwell completion fluid particles and granular reservoir rocks. These interactions contribute to a reservoir productivity reduction known as the “permeability damage” phenomenon.

Fundamental concepts of cake filtration and filter medium filtration were used to formulate mathematical models of particles capturing: gradual pore blocking, screening, and straining. The models provide theoretical bases for simple diagnostic plots in which the linearity of a plot becomes an indication of a prevailing mechanism of particles' capture.

Laboratory tests were run by pumping a completion fluid through synthetic simulated cores of unconsolidated sandstone gas reservoir samples from the Adriatic Sea. By using diagnostic plots and grade passing efficiency curves, the effects of total solids concentration particle size on the type and efficiency of the capture mechanism were investigated.

The study revealed the existence of three mechanisms of particle capture and the applicability of diagnostic plots for their detection. The onset of the straining mechanisms was attributed mainly to the total solids concentration while the duration of the gradual pore blockage phase was correlated with both particle size and concentration.     

Fabrication of Copper Nanowire Films and their Incorporation into Polymer Matrices for Antibacterial and Marine Antifouling Applications

With the ban of tributyltin, copper‐based biocides are now widely used in antifouling coatings as the major active ingredients. Given the past experience of heavy‐metal accumulation in harbors with limited water exchange, there is a significant interest in developing copper materials that greatly reduce the amount of copper ions released into marine surroundings. In this paper, copper nanowires (NWs) encapsulated in polymer matrices are investigated as the means to control the release of copper ions and to achieve a long‐lasting antifouling effect. Very long CuNWs with high aspect ratio in organic solution are drop‐coated onto substrates to fabricate uniform thin films. They are then incorporated into an elastomeric polydimethylsiloxane (PDMS) matrix. A small amount of CuNWs in PDMS can inhibit barnacle cyprid settlement, while it exhibits low mortality to cyprids and nauplii present in the surrounding seawater environment. The low levels of copper released after 50 days suggest that the intersecting and interconnected CuNWs embedded in PDMS could potentially release copper ions continuously over a few years in seawater. This approach provides a novel platform to use hybrid materials as effective marine antifouling coatings, and may be applied to fouling release materials to enhance their antifouling properties.     

Zur Theorie der Bewegung schwimmender Tiere

Ohne Zusammenfassung Schlu? des Aufsatzes aus Heft 6 (1965) S. 192/97.     

Neuere Fruchtkonserven

Ohne ZusammenfassungMitteilung aus dem Städtischen Nahrungsmittel-Untersuchungsamt von Budapest.     

In vivo evidence for increased apolipoprotein A-I catabolism in subjects with impaired glucose tolerance

The in vivo kinetics of the HDL apolipoproteins (apo) A-I and A-II were studied in six subjects with impaired glucose tolerance (IGT) and six control subjects with normal glucose tolerance (NGT), using a stable isotope approach. During a 12-h primed constant infusion of L-[ring-13C6]-phenylalanine, tracer enrichment was determined in apoA-I and apoA-II from ultracentrifugally isolated HDL. The rates of HDL apoA-I and apoA-II production and catabolism were estimated using a one-compartment model-based analysis. Triglycerides were higher in IGT subjects (1.33 +/- 0.21 vs. 0.84 +/- 0.27 mmol/l, P < 0.05), but were within the normal range. HDL cholesterol and apoA-I levels were significantly lower in subjects with IGT (1.07 +/- 0.15 vs. 1.36 +/- 0.14 mmol/l, P < 0.05; 0.94 +/- 0.10 vs. 1.34 +/- 0.07 g/l, P < 0.01). In IGT subjects, HDL composition was significantly altered, characterized by an increase in HDL triglycerides (4.9 +/- 1.9 vs. 3.2 +/- 1.0%, P < 0.05) and HDL phospholipids (34.7 +/- 2.6 vs. 27.5 +/- 5.8%, P < 0.05) and a decrease in HDL cholesteryl esters (10.1 +/- 2.0 vs. 12.7 +/- 2.9%, P < 0.05) and HDL apoA-I (31.5 +/- 4.4 vs. 43.2 +/- 2.4%, P < 0.05). The mean fractional catabolic rate (FCR) of HDL apoA-I was significantly higher in IGT subjects (0.34 +/- 0.05 vs. 0.26 +/- 0.03 day(-1), P < 0.01), while the HDL apoA-I production rate (PR), as well as the PR and FCR of HDL apoA-II, showed no differences between the two groups. There were significant correlations between HDL apoA-I FCR and the following parameters: HDL apoA-I (r = -0.902, P < 0.001), HDL cholesterol (r = -0.797, P = 0.001), plasma triglycerides (r = 0.743, P < 0.01), HDL triglycerides (r = 0.696, P < 0.01), and cholesterol ester transfer protein activity (r = 0.646, P < 0.01). We observed a strong positive association between increased apoA-I catabolism and insulin (r = 0.765, P < 0.01) and proinsulin (r = 0.797, P < 0.01) concentrations. These data support the hypothesis that the decrease in HDL cholesterol and apoA-I levels in IGT is principally the result of an enhanced apoA-I catabolism. The latter seems to be an early metabolic finding in IGT even when other lipid parameters, especially plasma triglycerides, still appear to be not or only weakly affected.     

朗度晨风 2.1-D音箱

打开包装我们第一的感觉是晨风2.1-D外观相当淡雅，见惯了黑色、灰色、银色、深褐色各种颜色沉稳的音箱，晨风2.1-D淡色调的木纹外观让人眼前一亮。     

Computer program for iterative evaluation of fractional turnover rates by exponential regression: application to the turnover of VLDL-triglycerides in blood

A microcomputer program ('EXREG') in GW BASIC was developed for fitting experimental data of A(T) to the equation A = A0 + A1.exp(-K.T) by exponential regression. In an iterative procedure K-values are tested to yield the maximum coefficient of determination. The accuracy of K is further improved in consecutive steps. The program is used to obtain the fractional turnover rate K of radiolabelled very low density lipoprotein (VLDL)-triglycerides in patients suffering from disturbances of lipid metabolism. A is the radioactivity of VLDL-triglycerides which is measured after isolation from blood. Seventeen consecutive blood samples are taken within a period of 24 h after injection of radioactive glycerol. T is the time after injection. The production rate of VLDL-triglycerides is calculated using K, the VLDL-triglyceride concentration, the body weight and height.