Effect of water immersion on the interlaminar and flexural performance of low cost liquid resin infused carbon fabric composites

This study investigates some potential benefits of using non-epoxy matrices in carbon fibre composites, targeting specific marine and wind energy applications. Water uptake during and after immersion for up to 28 days in deionised water at 40 °C, and the effects of such conditioning on the interlaminar shear and flexural performance of the composites with isophthalic polyester, vinyl ester and urethane acrylate matrices were compared to those of equivalent composites impregnated with three grades of epoxy resin. Results demonstrated that, although the epoxy systems perform equally or better than the alternative resins in the dry state, they are also more sensitive to property degradation due to water ingress. The relatively lower water absorption and subsequent limited reduction in performance of vinyl ester and urethane acrylate composites is sufficiently promising to justify further study.     

Enhanced expression of cyclin D1 in senescent human fibroblasts

When human fibroblast, TIG-1, was growth-stimulated with fetal bovine serum, the induction level of cell cycle-dependent genes was generally much lower in senescent cells than in young counterparts. Exceptionally, the expression level of cyclin D1 in senescent cells was constitutively higher than in young cells and further increased after serum stimulation, which was confirmed by Northern and Western blots and immunoprecipitation. This was also true in other human diploid fibroblast lines, TIG-3 and MRC-5. However, cyclin D1-dependent kinase activity was not detected in senescent cells. When sense- or antisense-cyclin D1 cDNA driven by beta-actin promoter was transfected into young TIG-1 cells, the number of appeared colonies from sense-strand transfected cultures was lower than that from antisense-strand-transfected ones. However, clones expressing cyclin D1 at low or undetectable level which were isolated after transfection with antisense-cyclin D1 proliferated up to the same division limit as untransfected and sense-strand transfected cells. Four clones of SV40-transformed TIG-1 expressed cyclin D1 at moderate levels during their extended proliferative lifespan. It appears that, if the extremely overexpressed cyclin D1 could cause an inhibition of cell proliferation at senescent stage, cellular senescence occurs regardless of overexpression of cyclin D1.     

Visualization of coronary arteries with helical scanning CT: diastolic reconstruction

The purpose of this study was the visualization of coronary arteries by the diastolic reconstruction method with helical scanning (HES) CT. We chose diastolic phase images from the image data acquired with the HES technique using a continuous nutate-rotate fast CT scanner, because few motion artifacts are induced by cardiac pulsation during the slow filling diastolic phase. We assessed coronary diseases using this method based on HES-CT, and evaluated its clinical effectiveness. We also studied the clinical value of multiplanar reconstruction and three-dimensional surface reconstruction. The subjects consisted of 31 patients with coronary disease, aged 41-77 years. When a diastolic reconstruction HES-CT was employed, the average rate of visualization of the coronary arteries was 72%. An examination can be completed during a 30-second single breath-hold, permitting the acquisition of coronary artery images with excellent continuity. Calcified coronary arteries can be identified.     

Development of a snowdrift wind tunnel

This paper describes an experiment and its result, using a snowdrift wind tunnel for the modeling of snowdrift formation, snow accretion and other phenomena caused by windborne snow particles.A wind tunnel of the closed-circuit type is considered by far the most suitable for the modeling of the phenomena mentioned above because conditions of air flow inside the tunnel are controlled by isolating them from conditions outside the tunnel.This suitability has been proved by the result obtained from an experiment conducted by constructing and using such a wind tunnel for modeling a snowdrift and snow accretion.     

Deciding probabilistic automata weak bisimulation: theory and practice

Weak probabilistic bisimulation on probabilistic automata can be decided by an algorithm that needs to check a polynomial number of linear programming problems encoding weak transitions. It is hence of polynomial complexity. This paper discusses the specific complexity class of the weak probabilistic bisimulation problem, and it considers several practical algorithms and linear programming problem transformations that enable an efficient solution. We then discuss two different implementations of a probabilistic automata weak probabilistic bisimulation minimizer, one of them employing SAT modulo linear arithmetic as the solver technology. Empirical results demonstrate the effectiveness of the minimization approach on standard benchmarks, also highlighting the benefits of compositional minimization.     

The behavior of charged conducting particles in electric fields

The presence of metal particles within a gas-insulated switchgear (GIS) might initiate a sparkover and lead to fatal failure of an electric power transmission system. In order to investigate the behavior of a particle in a GIS, the model electrodes and the measuring system are constructed. The motion of a particle was investigated by using a CCD camera and a high-speed video camera. Different shapes of elongated particles were made from 0.1-mm and 0.25-mm diameter wires. The measured values of lift-off field strength of a particle lying on the electrode agreed quite well with the theoretical predictions. The initial raising up of a particle usually started at the sharper edge, as expected. There were two types of different modes of particle motions: one is the bouncing motion between two electrodes or one electrode, and the other is the standing motion on the electrode. An interesting thing is that the standing motion is on the upper electrode, when a negative voltage is applied to the upper electrode. This phenomenon could be explained from the difference of positive and negative corona currents starting from both edges of a standing particle     

Fucoidan Hydrogels Significantly Alleviate Oxidative Stress and Enhance the Endocrine Function of Encapsulated Beta Cells

Microencapsulating pancreatic islets in immunoprotective alginate hydrogels is a promising strategy for treatment of type 1 diabetes. However, this strategy is limited by inflammation and hypoxia mediated oxidative stress, due to encapsulation and the hydrogel itself, leading to impaired insulin secretion and limited short and long term cell survival. Herein, the antioxidant effect of fucoidan, an algae derived polysaccharide, on beta cells, and its positive effects on encapsulated beta cell viability and function is presented. Fucoidan from Fucus vesiculosus (FF) exhibits a high total antioxidant capacity, and free radical scavenging activity, and is able to significantly alleviate intracellular oxidative stress in rat insolinoma beta cells (INS1E). In addition, FF significantly increases insulin secretion in a dose- and time-dependent manner. When FF is incorporated in ultrapure alginate used for microencapsulation of primary rat islets, both viability and glucose responsiveness of rat islets in these socalled Fucogel microcapsules (Fucocaps) are found to be significantly higher compared to islets encapsulated in alginate alone. Similar results are obtained with INS1E pseudoislets and neonatal pig islets. Fucocaps can provide a redox-modulatory niche and an immune barrier for islets and beta cells in the same time leading to significantly improved survival and endocrine function by mitigating oxidative stress.