The Essential Role of PRAK in Preserving Cardiac Function and Insulin Resistance in High-Fat Diet-Induced Diabetes

Regulated/activated protein kinase (PRAK) plays a crucial role in modulating biological function. However, the role of PRAK in mediating cardiac dysfunction and metabolic disorders remains unclear. We examined the effects of deletion of PRAK on modulating cardiac function and insulin resistance in mice exposed to a high-fat diet (HFD). Wild-type and PRAK^−/− mice at 8 weeks old were exposed to either chow food or HFD for a consecutive 16 weeks. Glucose tolerance tests and insulin tolerance tests were employed to assess insulin resistance. Echocardiography was employed to assess myocardial function. Western blot was used to determine the molecular signaling involved in phosphorylation of IRS-1, AMPKα, ERK-44/42, and irisin. Real time-PCR was used to assess the hypertrophic genes of the myocardium. Histological analysis was employed to assess the hypertrophic response, interstitial myocardial fibrosis, and apoptosis in the heart. Western blot was employed to determine cellular signaling pathway. HFD-induced metabolic stress is indicated by glucose intolerance and insulin intolerance. PRAK knockout aggravated insulin resistance, as indicated by glucose intolerance and insulin intolerance testing as compared with wild-type littermates. As compared with wild-type mice, hyperglycemia and hypercholesterolemia were manifested in PRAK-knockout mice following high-fat diet intervention. High-fat diet intervention displayed a decline in fractional shortening and ejection fraction. However, deletion of PRAK exacerbated the decline in cardiac function as compared with wild-type mice following HFD treatment. In addition, PRAK knockout mice enhanced the expression of myocardial hypertrophic genes including ANP, BNP, and βMHC in HFD treatment, which was also associated with an increase in cardiomyocyte size and interstitial fibrosis. Western blot indicated that deletion of PRAK induces decreases in phosphorylation of IRS-1, AMPKα, and ERK44/42 as compared with wild-type controls. Our finding indicates that deletion of PRAK promoted myocardial dysfunction, cardiac remodeling, and metabolic disorders in response to HFD.     

北美特种纸行业概况

从市场总量、产品分类、生产设备以及行业现状等方面,概括分析了北美地区特种纸行业的整体状况。北美地区58家特种纸公司每年产量总计约为300万t,其中5大特种纸公司各自所占市场份额均超过7%,排名前12位的公司总计占市场份额总量的69%。北美地区特种纸机平均产能居全球第一,但平均技术年龄也最高。造成这一局面的原因在于北美地区特种纸行业发展成熟、市场饱和,近年来对本行业的新投资远落后于全球其他地区。随着各种新技术、新材料的诞生以及对环保、可再生能源等领域的重视,北美特种纸行业将迎来新的发展机遇。     

Induction plasma spheroidization of ZrB2-SiC powders for plasma-spray coating

To improve the microstructure and properties of ZrB₂-SiC (ZrB₂-30?vol%SiC, Z7S3) coatings, a facile synthesis route involving induction plasma spheroidization (IPS) has been proposed, and the morphologies, particle size distributions, and phase compositions of the feedstock powders were analysed by scanning electron microscopy and focused ion beam techniques. The obtained results showed that the surfaces of the produced powders contained eutectic-like and granular zones. Owing to the existence of a temperature gradient, the internal microstructure of the IPS-treated powder exhibited a three-layered structure consisting of a ′surface shell′, a ′transition layer′, and a ′porous core′. Additionally, the properties of the IPS-treated samples were compared with those of the spray-dried (SD) powders. The former exhibited good plastic deformation properties, and their single splats contained flattened structures, while the single splats of the SD powder melted only partially retaining some of their original characteristics.     

Improved thermal shock resistance of SiCnw/PyC core-shell structure-toughened CVD-SiC coating

In-situ SiC nanowire (SiCnw)/pyrolytic carbon (PyC) core-shell structures were introduced to mainly improve the thermal shock performance of chemical vapor deposition (CVD)-SiC coating on carbon/carbon (C/C) composites. The microstructure, phase composition, and mechanical properties of the CVD-SiC coating toughened by SiCnw/PyC core-shell structures were studied as well. The results show that the introduction of SiCnw/PyC core-shell structures can effectively alleviate the mismatch of coefficient of thermal expansion (CTE) between SiC coating and C/C substrate, thus enhancing the thermal shock resistance of the coating. Furthermore, the increased numbers of interfaces in the SiC coating owing to the addition of core-shell structures are beneficial to the mechanical properties of the coating after thermal shock test.     

钢化玻璃白雾成因及解决方法

采用显微镜分析钢化白雾缺陷发现,钢化白雾是玻璃表面形成的凹坑,凹坑数量和大小不能量化白雾,且钢化白雾的表面形貌与进炉方向无关.针对白雾缺陷进行详细分析,给出具体的解决方法.     

Significantly enhanced breakdown field in Ca1-xSrxCu3Ti4O12 ceramics by tailoring donor densities

Significantly enhanced breakdown field of 24.52 kV cm^?1 as well as noteworthy nonlinear coefficient of 8.11 and low dielectric loss of 0.077 were obtained in Ca_0.6Sr_0.4Cu₃Ti₄O₁₂ ceramic. It was proved from impedance spectra that improved breakdown field was attributed to enhanced grain boundary resistance and elevated Schottky barrier height, which was further found resulting from reduced donor densities in C-V measurements. In addition, it was found that the activation energy originated from oxygen vacancies was increased, indicating the generation of oxygen vacancies was suppressed. Since oxygen vacancies acted as donors in depletion layers, it is reasonable to deduce that the reduced donor density was mainly ascribed to the decreased oxygen vacancies. In conclusion, maximum integrated action of strong solid solution effect and weak Sr-stretching effect was achieved when Sr/Ca ratio is 40/60, leading to greatly elevated potential barrier height and enhanced breakdown field consequently.     

Gelation properties of goose liver protein recovered by isoelectric solubilisation/precipitation process

Isoelectric solubilisation/precipitation (ISP) process was applied to goose liver (GL) for protein extraction. The gelation properties of proteins extracted by acid processes (ACP, pH 2.0, 2.5 and 3.0) and alkaline processes (ALP, pH 11.0, 11.5 and 12.0) were estimated, where the unextracted ground GL was set as the control. Nearly 58.39~79.00% of GL proteins were recovered by ISP treatments. High molecular weight (100~250 kDa) proteins were found to be partially hydrolysed by ACP, while few changes in proteins occurred during ALP. As evidenced by rheological and textural measurements, ALP proteins formed gels with high elasticity and superior texture, whereas ACP proteins had inferior gelation properties. Moreover, ALP proteins were able to form a highly interconnected and homogeneous three‐dimensional microstructure. Predominantly, gels produced by 11.0 had optimal texture and the lowest cooking loss (P < 0.05). These results suggested that the ISP process (ALP) is a potential method to improve the economic value of GL.     

An adaptive failure boundary approximation method for reliability analysis and its applications

Engineering with Computers - In practical engineering problems, accurate reliability assessment often is computationally expensive with time-consuming numerical models or simulation models. How to...     

A simple design approach to analyse the piled embankment including tensile reinforcement and subsoil contributions

There is not one generally accepted approach for the design of geogrid-reinforced pile-supported (GRPS) embankments. Relevant mechanisms include arching of the embankment material, but also the effect of geogrid reinforcement and potentially a contribution from the underlying subsoil. This paper presents a simple design approach to identify the contribution of all three mechanisms, in which the contribution of multi-layered geogrid reinforcement is also presented. To validate the theoretical predictions for the effect of geogrid reinforcement and the potential contribution of underlying subsoil, a series of three-dimensional finite element analyses are conducted. It is found that a point of ‘maximum arching’ is increased with the height of embankment. This study also presents that the reinforcement could reduce the ultimate stress on the subsoil. However, this requires significant sag of the reinforcement. It is found that the sag of reinforcement is very sensitive to the span of the reinforcement between piles, but relatively insensitive to the stiffness of the reinforcement. For a case with three layers of geogrid, the upper two grids carry relatively little tension compared to the bottom layer. This in turn leads to an approximate but simple equation of vertical equilibrium which may be of use in design.     

Transient Simulation of Hollow‐Fiber Membrane Filtration with Nonuniform Permeability Distribution

Transient simulation of filtration in hollow‐fiber membranes with nonuniform permeability distribution was conducted. The diversity of permeability distributions caused different initial flux and transmembrane pressure distributions. Manipulating the permeability distribution enables a hollow‐fiber membrane to achieve its maximum volumetric flow rate. During solid‐liquid separation, the inter‐adjustment between flux and cake distributions improved their uniformities simultaneously. The reciprocal of the volumetric flow rate of the membranes all increased linearly with water production. Severely nonuniform permeability distribution caused low water production. The numerical results could be applicable to account for the non‐ideal performance of industrial hollow‐fiber membrane modules.