55 research outputs found

    Simvastatin reduces atherogenesis and promotes the expression of hepatic genes associated with reverse cholesterol transport in apoE-knockout mice fed high-fat diet

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    <p>Abstract</p> <p>Background</p> <p>Statins are first-line pharmacotherapeutic agents for hypercholesterolemia treatment in humans. However the effects of statins on atherosclerosis in mouse models are very paradoxical. In this work, we wanted to evaluate the effects of simvastatin on serum cholesterol, atherogenesis, and the expression of several factors playing important roles in reverse cholesterol transport (RCT) in apoE-/- mice fed a high-fat diet.</p> <p>Results</p> <p>The atherosclerotic lesion formation displayed by oil red O staining positive area was reduced significantly by 35% or 47% in either aortic root section or aortic arch en face in simvastatin administrated apoE-/- mice compared to the control. Plasma analysis by enzymatic method or ELISA showed that high-density lipoprotein-cholesterol (HDL-C) and apolipoprotein A-I (apoA-I) contents were remarkably increased by treatment with simvastatin. And plasma lecithin-cholesterol acyltransferase (LCAT) activity was markedly increased by simvastatin treatment. Real-time PCR detection disclosed that the expression of several transporters involved in reverse cholesterol transport, including macrophage scavenger receptor class B type I, hepatic ATP-binding cassette (ABC) transporters ABCG5, and ABCB4 were induced by simvastatin treatment, the expression of hepatic ABCA1 and apoA-I, which play roles in the maturation of HDL-C, were also elevated in simvastatin treated groups.</p> <p>Conclusions</p> <p>We demonstrated the anti-atherogenesis effects of simvastatin in apoE-/- mice fed a high-fat diet. We confirmed here for the first time simvastatin increased the expression of hepatic ABCB4 and ABCG5, which involved in secretion of cholesterol and bile acids into the bile, besides upregulated ABCA1 and apoA-I. The elevated HDL-C level, increased LCAT activity and the stimulation of several transporters involved in RCT may all contribute to the anti-atherosclerotic effect of simvastatin.</p

    Properties of Alkali-Resistant Glass Fiber Reinforced Coral Aggregate Concrete

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    The intention of this paper is to analyze the properties of coral aggregate concrete (CAC) that is reinforced by alkali-resistant glass fibers (ARGF) and the bond performance with BFRP (basalt fiber reinforced polymer) bars. Two types of ARGF, denoted by Type A and Type B with different manufacturing technologies and fiber lengths, are used in the test. Tests of compressive strength, splitting tensile strength, and flexural performance were performed on ARGF-CAC with four different contents for the two types of ARGF. It is found that the cubic compressive strength is slightly reduced when the fiber volume fraction exceeds 0.5%, but almost keeps invariable if the fiber content further increases. However, the tensile strength, residual strength retention and flexural toughness are improved as more ARGFs are added into CAC, and even higher with Type B ARGF addition. The optimized volume fraction is 1.5% for both the two types of ARGF based on the evaluation of the workability and mechanical performance. Moreover, central pull-out test was performed to study the bond properties of ARGF-CAC with BFRP bars. It is found that both the maximum average bond stress and residual frictional stress are generally reduced as the bond length is longer. The addition of Type B ARGFs can significantly improve the bond strength; however, the Type A ARGFs seem to have marginal effect

    Ultra-Short Pulsed Laser Manufacturing and Surface Processing of Microdevices

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    Ultra-short laser pulses possess many advantages for materials processing. Ultrafast laser has a significantly low thermal effect on the areas surrounding the focal point; therefore, it is a promising tool for micro- and submicro-sized precision processing. In addition, the nonlinear multiphoton absorption phenomenon of focused ultra-short pulses provides a promising method for the fabrication of various structures on transparent material, such as glass and transparent polymers. A laser direct writing process was applied in the fabrication of high-performance three-dimensional (3D) structured multilayer micro-supercapacitors (MSCs) on polymer substrates exhibiting a peak specific capacitance of 42.6ā€ÆmFĀ·cmāˆ’2 at a current density of 0.1ā€ÆmAĀ·cmāˆ’2. Furthermore, a flexible smart sensor array on a polymer substrate was fabricated for multi-flavor detection. Different surface treatments such as gold plating, reduced-graphene oxide (rGO) coating, and polyaniline (PANI) coating were accomplished for different measurement units. By applying principal component analysis (PCA), this sensing system showed a promising result for flavor detection. In addition, two-dimensional (2D) periodic metal nanostructures inside 3D glass microfluidic channels were developed by all-femtosecond-laser processing for real-time surface-enhanced Raman spectroscopy (SERS). The processing mechanisms included laser ablation, laser reduction, and laser-induced surface nano-engineering. These works demonstrate the attractive potential of ultra-short pulsed laser for surface precision manufacturing. Keywords: Ultra-short pulsed laser processing, Microdevices, Supercapacitor, Electronic tongue, Surface-enhanced Raman spectroscop

    A study of high-strength and durable cotton fabric joining via laser-induced polymerisation of silica-sol photosensitive resin

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    Cotton is the most popular fabric used in human clothing and garment, and its joining process is still based on the traditional sewing method. In this study, a new approach to cotton fabric joining via UV-laser induced polymerisation was investigated, which involved preparation of a silane coupling agent (3-Aminopropyl) triethoxysilane (3-Aps) for surface modification of cotton fabric, and formulation and application of a silica-sol photosensitive resin as the filler. The developed resin consists of two other silanes, Silane A174 and KH560 so as to provide chemical bonds with the cellulose of cotton surface and the 3-Aps modified cotton. The results showed that the silica-sol resin not only produced self-polymerisation due to photothermal effect, but also joined with the fiber surfaces by chemical bonding, which enhanced the surface interaction with cotton fibers and obtained excellent mechanical properties. The heat accumulation at joint was detected in real-time using the infrared thermography, which ensured the fast drying and curing of the silica-sol containing resin. With 4Ā % silica-sol content in resin, the interfacial bonding was optimal for APS-Fabric, and the tensile force of the 2Ā mm joint reached 300Ā N exceeding the ultimate breaking strength of the cotton fabric itself. The fabric joint was demonstrated to withstand at least 20 washing cycles without cracking. This new fabric joining technique provides both strong bonding and sufficient flexibility in the joints, resulting in high strength and durable cotton fabric joining, which has a broad application prospect in the field of apparel

    Impacts of Arctic Sea Fog on the Change of Route Planning and Navigational Efficiency in the Northeast Passage during the First Two Decades of the 21st Century

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    Under the background of climate change, the Northeast Passageā€™s navigability is on the rise. Arctic sea fog significantly influences navigational efficiency in this region. Existing research primarily focuses on routes accumulating the lowest distance, neglecting routes with the lowest time and sea fogā€™s influence on route planning and navigational efficiency. This study compares the fastest and shortest routes and analyzes Arctic sea fogā€™s impact on the Northeast Passage from June to September (2001ā€“2020). The results show that coastal areas are covered with less sea ice under notable monthly variations. Sea fog frequency is highest near coasts, declining with latitude. September offers optimal navigation conditions due to minimal ice and fog. When only sea ice is considered, the fastest route is approximately 4 days quicker than the shortest. The shortest route has migrated towards the higher latitude over two decades, while the fastest route remains closer to the Russian coast. Adding the impact of sea fog on the fastest route, the speed decreased by 30.2%, increasing sailing time to 45.1%. The new fastest route considering both sea ice and sea fog achieved a 13.9% increase in sailing speed and an 11.5% reduction in sailing time compared to the original fastest route

    Performance audit evaluation of marine development projects based on SPA and BP neural network model

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    Accurately grasping the comprehensive cost-benefit and influencing factors of various marine development projects is of great significance to the promotion of high-quality marine development. This work screened and constructed the performance audit evaluation index system of comprehensive cost-benefit of marine development projects from the four aspects including society, economy, resources, and environment. The entropy weight set pair analysis (SPA) was used to audit and evaluate the comprehensive cost-benefit of 15 marine development projects during the construction and operation period. The back propagation (BP) neural network model was used to test the results. The main influencing factors were analyzed by the grey relational analysis (GRA) model. It was found that the comprehensive cost-benefit performance audit evaluation index of the six projects of marine protected area and offshore wind power were higher than the other nine projects of mariculture, sewage dumping, and port industry. The main influencing factors were economic net income, loss of wetland ecological service value, environmental pollution prevention and control cost, new addition employment rate, etc. The countermeasures suggestions were put forward

    Experimental investigation and analytical prediction on bond behaviour of CFRP-to-concrete interface with FRP anchors

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    Hybrid bonded technology with fiber-reinforced polymer (FRP) anchors can effectively improve the load capacity of carbon fiber-reinforced polymer (CFRP)-to-concrete interface. To investigate the reinforcement effect of FRP anchors, tensile shear tests of seventeen CFRP-concrete bonded joints with additional FRP anchors were conducted in this paper. The effects of the construction sequence, anchor position, and type of FRP anchor were considered in the experimental investigation. It was found that bonding CFRP sheet before installing FRP anchor and construction simultaneously could ensure the integrity of FRP anchor and provide a better anchor effect. The ultimate load-carrying capacity was increased with the increasing of plate length after anchor, that is the effect of anchor position. From the results of specimens with different types of FRP anchors at the same location, the FRP anchor composed of multiple small anchors can take effect earlier. By fitting the test results, the exponential bond-slip model for the CFRP-to-concrete interface and the elastic constitutive model for the FRP anchor were obtained. Further, substituting the two constitutive models, analytic theoretical models for load-slip curves and strain distribution were derived to predict the bond behavior of FRP anchored CFRP-to-concrete interface in this paper. The comparison between the prediction results and experimental data shows the good predictive accuracy of these analytical models

    Prediction of Surface Roughness in Gas-Solid Two-Phase Abrasive Flow Machining Based on Multivariate Linear Equation

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    The main purpose of this study is to explore a surface roughness prediction model of Gas-Solid Two-Phase Abrasive Flow Machining. In order to achieve the above purpose, an orthogonal experiment was carried out. Q235 steel as processing material and white corundum with different particle sizes as abrasive particles were used in the experiment. Shape and spindle speed were the main reference factors. The range method and factor trend graph are used to comprehensively analyze the experimental results of different processing stages of the detection point, and the optimal parameter combination of A3B2C1D2 was obtained. According to the experimental results, a multiple linear regression equation was established to predict the surface roughness, and the experimental results were solved and significantly analyzed by software to obtain a highly reliable prediction model. Through experiments, modeling and verification, it is known that the maximum error between the obtained model and the actual value is 0.339 Ī¼m and the average error is 0.00844 Ī¼m, which can better predict the surface roughness of the gas-solid two-phase flow abrasive pool
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