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761.
Human plasma of 5 normolipemic individuals was incubated for 24 hr at 37 C in the presence or in the absence of lecithin:
cholesterol acyltransferase (LCAT)-inhibitors. Plasma steored at 4 C served as a control. The low density lipoprotein (LDL)
fractions of the samples were isolated and investigated with respected to changes in chemical composition and complexing activity
with glycosamino glycans (GAG).
Incubation of plasma in the presence of LCAT inhibitors caused a significant increase of LDL triglycerides at the expense
of cholesteryl esters. Incubation with active LCAT not only changed the core but also the surface constituents (decrease in
phospholipids and in free cholesterol).
The amount of GAG bound per mg of LDL was not uniformly changed in samples incubated after LCAT inhibition. LDL isolated from
plasma incubated in the presence of LCAT, on the other hand, showed a significant reduction in GAG binding.
The ratio of free cholesterol: GAG in the complex was most significantly reduced in LCAT-modified LDL. There was in addition
a highly significant correlation between the LDL:GAG ratio in the complex and the free cholesterol and phospholipid content
of the LDL samples.
It is concluded that alterations in surface lipid constitutents of LDL strongly after their interaction with sulfated polysaccharides,
an effect which may be relevant also in vivo for the interaction of LDL with cell surfaces and intercellular matrices. 相似文献
762.
Albrecht Seher Ingo Helmut Dorn Hubert Engelhardt Wolfgang Gruber Karl Walter Maichel 《化学,工程师,技术》1988,60(9):691-698
The radioactive tracer method in the chemical industry. In the chemical industry the radioactive tracer method has become a method of analysis with a variety of applications, which range from determining traces of biologically active substances to process analysis in production plants. Process analysis, for instance the determination of residence-time distributions or of intermingling of streams of different substances, can be carried out under widely varying operating conditions. If the streams of material are labelled with gamma-ray emitters the distribution of the tracers can be determined by means of detectors outside the plant. To demonstrate the possible applications of the method to process analysis, measurements in three different plants are described. Exhaust gases were labelled with Ar-41 to determine the residence-time distribution in plant for the combustion of waste residues consisting of a rotary tube furnace, an afterburn chamber, and a waste-heat boiler. The waste water entering the activation tank of sewage-treatment plant was labelled with Na-24 to determine its residence-time distribution. Individual particles labelled with Mn-56 were used to investigate mixing of the powder in the stirred-bed reactor of a polypropylene plant. The knowledge gained from these measurements has contributed to optimization of existing and planned plant. 相似文献
763.
Bresson Francois; De Schonen Scania; Furth Hans; Gillieron Christiane; Gruber Howard E.; Voyat Gilbert 《Canadian Metallurgical Quarterly》1977,32(5):385b
Draws attention to the omission of Dr. Alina Szeminska's name from the English translation of The Child's Conception of Number. The book, published in French in 1941, was coauthored by Jean Piaget and Szeminska. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
764.
VF Okhotnikova LK Grakovskaia VG Koroleva GS Minasova IR Zak 《Canadian Metallurgical Quarterly》1976,21(8):719-721
Relation between the rate of tetracycline dissolution from tablets and capsules and the biological acceptibility of the antibiotic in the host was studied. The antibiotic dissolution rate from the pharmaceutical forms was determined in a modernized apparatus "Rotary basket" in water, the speed of the basket rotation was 200 r.p.m. In addition the tetracycline blood levels in patients treated with the drug in the above pharmaceutical forms were estimated. It was found that the rate of the antibiotic dissolution characterized the antibiotic biological acceptibility. A test for the dissolution rate was developed. It may be used for estimation of production batches of tetracycline tablets. 相似文献
765.
We study the hardness of approximation of clause minimum and literal minimum representations of pure Horn functions in n Boolean variables. We show that unless P=NP, it is not possible to approximate in polynomial time the minimum number of clauses and the minimum number of literals of pure Horn CNF representations to within a factor of \(2^{\log^{1-o(1)} n}\) . This is the case even when the inputs are restricted to pure Horn 3-CNFs with O(n 1+ε ) clauses, for some small positive constant ε. Furthermore, we show that even allowing sub-exponential time computation, it is still not possible to obtain constant factor approximations for such problems unless the Exponential Time Hypothesis turns out to be false. 相似文献
766.
Visualizing Oxidative Cellular Stress Induced by Nanoparticles in the Subcytotoxic Range Using Fluorescence Lifetime Imaging
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Jens Balke Pierre Volz Falko Neumann Robert Brodwolf Alexander Wolf Hannah Pischon Moritz Radbruch Lars Mundhenk Achim D. Gruber Nan Ma Ulrike Alexiev 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(23)
Nanoparticles hold a great promise in biomedical science. However, due to their unique physical and chemical properties they can lead to overproduction of intracellular reactive oxygen species (ROS). As an important mechanism of nanotoxicity, there is a great need for sensitive and high‐throughput adaptable single‐cell ROS detection methods. Here, fluorescence lifetime imaging microscopy (FLIM) is employed for single‐cell ROS detection (FLIM‐ROX) providing increased sensitivity and enabling high‐throughput analysis in fixed and live cells. FLIM‐ROX owes its sensitivity to the discrimination of autofluorescence from the unique fluorescence lifetime of the ROS reporter dye. The effect of subcytotoxic amounts of cationic gold nanoparticles in J774A.1 cells and primary human macrophages on ROS generation is investigated. FLIM‐ROX measures very low ROS levels upon gold nanoparticle exposure, which is undetectable by the conventional method. It is demonstrated that cellular morphology changes, elevated senescence, and DNA damage link the resulting low‐level oxidative stress to cellular adverse effects and thus nanotoxicity. Multiphoton FLIM‐ROX enables the quantification of spatial ROS distribution in vivo, which is shown for skin tissue as a target for nanoparticle exposure. Thus, this innovative method allows identifying of low‐level ROS in vitro and in vivo and, subsequently, promotes understanding of ROS‐associated nanotoxicity. 相似文献
767.
768.
Modern distributed systems are diverse and dynamic, and consequently difficult to manage using traditional approaches, which rely on an extensive initial knowledge of the system. On the performance front, these systems often offer multiple opportunities for dynamically degrading or improving service level based on workload intensity, to avoid overload and underload. In this context, we propose a novel approach for building distributed systems capable of autonomously deciding when and how to adapt service level. Our approach limits the knowledge that must be provided manually to a component‐based representation of the system. From this representation, we build and maintain a performance profile, which allows us to (1) identify the most promising adaptations based on workload type and (2) dynamically characterize the intrinsic efficiency of each adaptation based on past attempts. We have successfully implemented and evaluated a prototype of our approach in the context of multi‐tiered application servers. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
769.
770.
Günther Weichslberger Heinrich Gruber Simone Knaus Christian Hansmann 《Holz als Roh- und Werkstoff》2007,26(2):403-405
A novel method for the determination of the water content in wood has been developed and experimentally
tested. Based on the reaction of trimethylchlorosilane with various wood constituents and water, the generation
of a by-product (hexamethyldisiloxane) was pursued and quantified via gas-chromatography and the water
content was subsequently calculated back. The experiments were carried out with preconditioned spruce wood
meal (particle sizes ranging between 60 and 140 microns) using water free solvents and reagents in
a water free reaction atmosphere. The results showed that the investigated samples incorporated around
10 wt. % of water after preconditioning for 48 h. 相似文献