Molecular weight determination of the hepatic vasopressin receptor with a high-affinity photoprobe

We report here a study of photoaffinity labeling of the V1a-vasopressin receptor with high-affinity, V1-specific radioiodinated antagonist ligands: one containing an azidophenylalanine residue ([beta,beta-dimethyl-beta-mercaptopropionyl(1), p-azido-Phe2,Val4,Lys8,D-Tyr9] vasopressin), two others containing nitrophenylalanine, and one, highly similar but without a photosensitive function, as control. All analogues competed in the dark for the same binding site with vasopressin. Long-wavelength UV irradiation of rat liver membranes incubated in presence of the radio-iodinated azido photolabel produced a specifically labeled protein band at 53 kDa in SDS-PAGE. Identical experiments with the nitrophenylalanyl peptides produced only non-specific labeling and control experiments with the non-photosensitive analogue produced no labeling at all. Chemical crosslinking of 3H-VP to the same membrane preparation produced a result identical to that of the azido photolabel, confirming the receptor nature of the labeled protein. Deglycosylation of the labeled receptor with endoglycosidase F reduced the observed molecular weight of 53 kDa to 43 kDa. The molecular parameters reported herein of the presumed hepatic vasopressin receptor confirm the values deduced from the molecular cloning of the rat V1a receptor.     

Laser melting treatment by overlapping passes of preheated nickel electrodeposited coatings on Al−Si alloy

Microstructure improvements of a nickel electrodeposited Al−Si alloy were studied after high-power laser melting treatment through a single pass or partially overlapping successive adjacent passes. In some cases, laser melting treatment was preceded by a 5-hour heating of the specimens at 500°C in argon atmosphere furnace. Microstructure observations and microhardness measurements were carried out on the specimens before and after laser melting treatment with and without preheating. Best results concerning microhardness, microstructural homogeneity, and porosity elimination, as well as adhesion of the nickel coating on the Al−Si alloy, were achieved when the specimens were first subjected to heating at 500°C in an argon atmosphere furnace for 5 hours and then submitted to a laser melting treatment through successive adjacent laser passes with an overlapping rate of 70 pct. Microstructure studies were carried out employing X-ray diffraction analysis (XRD) and energy-dispersive spectrometry (EDS). AlNi and Al₃Ni phases were detected in the diffusion area which resulted from the 5-hour heating. AlNi, Al₃Ni, and Al₃Ni₂ phases were identified in the laser melted zones (LMZs). Each one of the above phase was found to be the main phase under different conditions.     

High Stiffness Cellulose Fibers from Low Molecular Weight Microcrystalline Cellulose Solutions Using DMSO as Co‐Solvent with Ionic Liquid

There is a need to develop high‐performance cellulose fibers as sustainable replacements for glass fibers, and as alternative precursors for carbon filaments. Traditional fiber spinning uses toxic solvents, but in this study, by using dimethyl sulfoxide (DMSO) as a co‐solvent with an ionic liquid, a novel high‐performance fiber with exceptional mechanical properties is produced. This involves a one‐step dissolution, and cost‐effective route to convert high concentrations of low molecular weight microcrystalline cellulose into high stiffness cellulose fibers. As the cellulose concentration increases from 20.8 to 23.6 wt%, strong optically anisotropic patterns appear for cellulose solutions, and the clearing temperature (T _c) increases from ≈100 °C to above 105 °C. Highly aligned, stiff cellulose fibers are dry‐jet wet spun from 20.8 and 23.6 wt% cellulose/1‐ethyl‐3‐methylimidazolium diethyl phosphate/DMSO solutions, with a Young's modulus of up to ≈41 GPa. The significant alignment of cellulose chains along the fiber axis is confirmed by scanning electron microscopy, wide‐angle X‐ray diffraction, and powder X‐ray diffraction. This process presents a new route to convert high concentrations of low molecular weight cellulose into high stiffness fibers, while significantly reducing the processing time and cost.     

Premixed Flames Under Microgravity and Normal Gravity Conditions

Premixed conical CH₄-air flames were studied experimentally and numerically under normal straight, reversed gravity conditions and microgravity. Low-gravity experiments were performed in Drop tower. Classical Bunsen-type burner was used to find out features of gravity influence on the combustion processes. Mixture equivalence ratio was varied from 0.8 to 1.3. Wide range of flow velocity allows to study both laminar and weakly turbulized flames. High-speed flame chemoluminescence video-recording was used as diagnostic. The investigations were performed at atmospheric pressure. As results normalized flame height, laminar flame speed were measured, also features of flame instabilities were shown. Low- and high-frequency flame-instabilities (oscillations) have a various nature as velocity fluctuations, preferential diffusion instability, hydrodynamic and Rayleigh-Taylor ones etc., that was explored and demonstrated.     

Focussed crawling of environmental Web resources based on the combination of multimedia evidence

Focussed crawlers enable the automatic discovery of Web resources about a given topic by automatically navigating the Web link structure and selecting the hyperlinks to follow by estimating their relevance to the topic based on evidence obtained from the already downloaded pages. This work proposes a classifier-guided focussed crawling approach that estimates the relevance of a hyperlink to an unvisited Web resource based on the combination of textual evidence representing its local context, namely the textual content appearing in its vicinity in the parent page, with visual evidence associated with its global context, namely the presence of images relevant to the topic within the parent page. The proposed focussed crawling approach is applied towards the discovery of environmental Web resources that provide air quality measurements and forecasts, since such measurements (and particularly the forecasts) are not only provided in textual form, but are also commonly encoded as multimedia, mainly in the form of heatmaps. Our evaluation experiments indicate the effectiveness of incorporating visual evidence in the link selection process applied by the focussed crawler over the use of textual features alone, particularly in conjunction with hyperlink exploration strategies that allow for the discovery of highly relevant pages that lie behind apparently irrelevant ones.     

Characterization of the Impact of Hardware Islands on OLTP

Modern hardware is abundantly parallel and increasingly heterogeneous. The numerous processing cores have non-uniform access latencies to the main memory and processor caches, which causes variability in the communication costs. Unfortunately, database systems mostly assume that all processing cores are the same and that microarchitecture differences are not significant enough to appear in critical database execution paths. As we demonstrate in this paper, however, non-uniform core topology does appear in the critical path and conventional database architectures achieve suboptimal and even worse, unpredictable performance. We perform a detailed performance analysis of OLTP deployments in servers with multiple cores per CPU (multicore) and multiple CPUs per server (multisocket). We compare different database deployment strategies where we vary the number and size of independent database instances running on a single server, from a single shared-everything instance to fine-grained shared-nothing configurations. We quantify the impact of non-uniform hardware on various deployments by (a) examining how efficiently each deployment uses the available hardware resources and (b) measuring the impact of distributed transactions and skewed requests on different workloads. We show that no strategy is optimal for all cases and that the best choice depends on the combination of hardware topology and workload characteristics. Finally, we argue that transaction processing systems must be aware of the hardware topology in order to achieve predictably high performance.