Arachidonic acid release from mammalian cells transfected with human groups IIA and X secreted phospholipase A(2) occurs predominantly during the secretory process and with the involvement of cytosolic phospholipase A(2)-alpha

Stable expression of human groups IIA and X secreted phospholipases A(2) (hGIIA and hGX) in CHO-K1 and HEK293 cells leads to serum- and interleukin-1beta-promoted arachidonate release. Using mutant CHO-K1 cell lines, it is shown that this arachidonate release does not require heparan sulfate proteoglycan- or glycosylphosphatidylinositol-anchored proteins. It is shown that the potent secreted phospholipase A(2) inhibitor Me-Indoxam is cell-impermeable. By use of Me-Indoxam and the cell-impermeable, secreted phospholipase A(2) trapping agent heparin, it is shown that hGIIA liberates free arachidonate prior to secretion from the cell. With hGX-transfected CHO-K1 cells, arachidonate release occurs before and after enzyme secretion, whereas all of the arachidonate release from HEK293 cells occurs prior to enzyme secretion. Immunocytochemical studies by confocal laser and electron microscopies show localization of hGIIA to the cell surface and Golgi compartment. Additional results show that the interleukin-1beta-dependent release of arachidonate is promoted by secreted phospholipase A(2) expression and is completely dependent on cytosolic (group IVA) phospholipase A(2). These results along with additional data resolve the paradox that efficient arachidonic acid release occurs with hGIIA-transfected cells, and yet exogenously added hGIIA is poorly able to liberate arachidonic acid from mammalian cells

ADP Ribosylation Factors 1 and 4 and Group VIA Phospholipase A2 Regulate Morphology and Intraorganellar Traffic in the Endoplasmic Reticulum–Golgi Intermediate Compartment

In search of morphological determinants for the endoplasmic reticulum-Golgi intermediate compartment (ERGIC), we found that a concerted action of Arf1, Arf4, and PLA2G6-A controls the architecture of the ERGIC by regulating tubular carriers. This is predicted to impact the rate of transport and destination of cargos in the ERGIC

Effect of spark plasma sintering pressure on mechanical properties of WC-7.5wt% Nano Co

Abstract not availableMd. Raihanuzzaman Rumman, Zonghan Xie, Soon-Jik Hong, Reza Ghomashch

Effects of electromagnetic stirring and superheat on the microstructural characteristics of Al-Si-Fe alloy

Semisolid metal (SSM) processing is getting momentum to be the preferred fabrication route for near or net-shaped castings. For SSM processing of Al-Si alloys, there are two important microstructural features which influence the properties of finished products. These are the size and morphology of the primary α-Al phase and the eutectic matrix which consists of silicon, aluminum, and intermetallic phases. The presence of iron is beneficial to reduce the soldering effects in permanent mold castings, but it is unfavorable due to formation of a range of intermetallic phases. The casting parameters play an important role in avoiding the segregation of thin platelets of Fe-intermetallic, which is detrimental to mechanical properties. In this context, it is of particular interest to see the effects of melt stirring on the formation of eutectic silicon flakes and iron-based intermetallics during SSM processing. The effects of process parameters such as cooling rate and superheat are investigated on the morphology and size distribution of eutectic silicon and iron-based intermetallics during application of electromagnetic stirring (EMS). It is concluded that melt stirring not only alters the morphology of α-Al phase to rosette or globule shape, but also refines the eutectic silicon and iron-intermetallics. © 2006 Elsevier B.V. All rights reserved.S. Nafisi, D. Emadi, M.T. Shehata, R. Ghomashch

Effect of Stirring on the Silicon Morphological Evolution in Hypoeutectic Al-Si Alloys

Semi-Solid Metal, SSM, Processing is a relatively new technology to fabricate near or net-shaped casting products. In contrast to conventional casting routes, i.e. starting material is fully liquid, casting begins with the mushy alloy. For SSM processing of Al-Si alloys, there are two important microstructural features to influence the properties of the finished products. These are the size, shape and volume fraction of the primary α-Al phase and the morphology of silicon within the eutectic regions. It is well known that the irregular growth mode of eutectic Si can be modified by addition of modifiers such as strontium or sodium. In this paper, it will be shown that during SSM processing of Al-Si alloys; melt stirring not only alters the morphology of α-Al phase to rosette or globule shape, but also refines the eutectic silicon.Sh. Nafisi, R. Ghomashchi, D. Emadi, and M.T. Shehatahttp://iweb.tms.org/Purchase/ProductDetail.aspx?Product_code=05-5808-

Reliable Assay of Acid Sphingomyelinase Deficiency with the Mutation Q292K by Tandem Mass Spectrometry

Photograph of a scene on Kaw Lake

Fluid and heat transfer characteristics of aqueous graphene nanoplatelet (GNP) nanofluid in a microchannel

In the present work, thermo-physical properties of aqueous Graphene Nanoplatelet (GNP) at various mass concentrations of GNPs was experimentally measured. An experimental investigation was conducted to quantify the heat transfer coefficient, friction factor, pressure drop value, pumping power and thermo-hydraulic performance index of the nanofluid within a microchannel at various heat flux and Reynolds number. Results showed that GNP/water nanofluid can plausibly enhance the heat transfer coefficient and the Nusselt number by ~80%. In addition, a small increase in the friction factor and the pressure drop value was seen, which was attributed to the augmentation in the friction forces. The maximum increase in the pressure drop was 18.3% recorded at the highest Reynolds number and the highest mass concentration of the nanofluid. Also, despite the augmentation in the pressure drop value, the thermal performance of the system increased by 76% showing the great potential of the GNP/water nanofluid cooling and/or heating applications despite ~20% augmentation in the pumping power at Reynolds number > 1376. The enhancement in the thermal performance of the system was attributed to the thermophoresis effect, Brownian motion and the enhancement in the thermal conductivity of the nanofluid due to the presence of the GNP nanoplatelets.M.M. Sarafraz, B. Yang, O. Pourmehran, M. Arjomandi, R. Ghomashch