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Shear Conditions (shear + condition)
Selected AbstractsTwo novel monoclonal antibodies to VWFA3 inhibit VWF-collagen and VWF-platelet interactionsJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 9 2007Y. ZHAO Summary.,Background:,The interaction of collagen-von Willebrand factor (VWF)-GPIb is essential for platelet adhesion, especially under high shear conditions. VWF, which acts as a bridge between platelets and exposed subendothelium, interacts with collagen through its A3 domain, which is a new target for the antithrombotic agent. Objective:,To develop functional blockers that specifically inhibit VWF-dependent adhesion of platelets to collagen under high shear stress. Methods:,To develop murine antihuman VWF A3 monoclonal antibodies (mAbs) by standard hybridoma technology, and characterize their abilities to block interactions between VWF A3 and collagen as well as platelet function. Results:,Thirty anti-VWF-A3 mAbs were obtained. Among them, two mAbs, designated as SZ-123 and SZ-125, were found to inhibit VWF-collagen type III interaction. SZ-123 and SZ-125 inhibited the binding of purified human VWF (1.5 or 3 ,g mL,1) to human placenta collagen type III (IC50 = 0.07 ± 0.02 and 0.15 ± 0.03 ,g mL,1, respectively) or to calf skin collagen type III (IC50 = 0.48 ± 0.06 and 0.51 ± 0.07 ,g mL,1, respectively) coated on plates. Under flow shear condition (1000 s,1), SZ-123 and SZ-125 inhibited platelet adhesion on human placenta collagen- or calf skin collagen-coated surfaces. Both mAbs also inhibited platelet aggregation induced by ristocetin, botrocetin or bovine plasma. Conclusions:,SZ-123 and SZ-125 inhibited VWF-collagen and VWF-platelet interactions. [source] Metabolic profiling as a tool for understanding defense response of Taxus Cuspidata cells to shear stressBIOTECHNOLOGY PROGRESS, Issue 5 2009Pei-Pei Han Abstract To obtain a better understanding of responsive mechanism of plant cells in response to hydrodynamic mechanical stress, a metabolic profiling approach was used to profile metabolite changes of Taxus cuspidata cells under laminar shear stress. A total of 65 intracellular metabolites were identified and quantified, using gas chromatography coupled to time-of-flight mass spectrometry. Potential biomarkers were found by the principal component analysis as well as partial least squares combined with variable influence in the projection. Trehalose, sorbitol, ascorbate, sucrose, and gluconic acid were mainly responsible for the discrimination between shear stress induced cells and control cells. Further analysis by mapping measured metabolite concentrations onto the metabolic network revealed that shear stress imposed restrictions on primary metabolic pathways by inhibiting tricarboxylic acid cycle, glycolysis, and N metabolism. To adapt to the shear condition, cells responded by starting defensive programs. These defensive programs included coinduction of glycolysis and sucrose metabolism, accumulation of compatible solutes, and antioxidative strategy. A strategy of defense mechanisms at the level of metabolites for T. cuspidata cells when challenged with the shear stress was proposed. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] Magnetic Resonances in ECR-Heated Plasmas of the TJ-II HeliacCONTRIBUTIONS TO PLASMA PHYSICS, Issue 6-7 2010D. López-Bruna Abstract Low order rational values of the rotational transform ,magnetic resonances, for brevity, can be present inside ECR,heated plasmas of the TJ-II Heliac, in low magnetic shear conditions, without causing damage to confinement. Moreover, in agreement with previous experience in the TJ-II, the resonances seem to benefit confinement and are associated to changes in the radial electric field, at least in the density gradient region. These results encourage considering magnetic resonances as possible external actuators on confinement in stellarator/heliotron devices (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Viscosity measurements of ethylene glycol solution with flow drag reduction additivesHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 8 2006Naoto Haruki Abstract The viscous characteristics of ethylene glycol (EG) solution with flow drag reduction additive have been investigated experimentally. In this study, oleyldihydoroxyetyl amineoxide (ODEAO) was used as the flow drag reduction additive, and an aqueous solution of EG was used as a secondary refrigerant. The viscosity of the EG solution with ODEAO was measured with a rotational rheometer. The experimental parameters of viscosity measurement were the temperature of the EG solution with ODEAO, the ODEAO concentration, and the EG concentration. From the experimental results, the apparent viscosity of the EG solution with ODEAO showed SIS (shear induced state). The non-linear dependence of shear stress on shear rate has been well approximated by the power-law model under high shear conditions. The power-law contents, pseudoplastic viscosity, and index number have been estimated for each experimental parameter. Using the measured viscosity and non-dimensional analysis, the flow drag and heat transfer reduction effect of the EG solution with ODEAO has been investigated. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 35(8): 553,567, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20134 [source] USE OF EXTRUSION-TEXTURIZED WHEY PROTEIN ISOLATES IN PUFFED CORN MEALJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 2010C.I. ONWULATA ABSTRACT Adding whey protein concentrates or isolates to expanded snack foods would boost their nutritional content; however, adding non-textured whey proteins in amounts larger than 5% interferes with expansion, making the products less crunchy. To counter this effect, whey protein isolate (WPI) was first extruded (texturized) at either 50C (WPI-50) or 90C (WPI-100) before adding to corn meal at 25% (WPI) level, and was extruded again to make the puffed product. Corn meal, corn meal with non-texturized WPI (25%), corn meal with WPI-50, or corn meal with WPI-100 were extruded at high shear conditions (300 rpm) and product temperatures of 125C. All extrudates containing texturized WPI were more expanded, firmer, crispier and easier to break than corn meal or corn meal with non-texturized WPI. Pre-texturizing whey proteins and using them in extruded snacks improves textural properties, making it possible to add large amounts of whey proteins directly into expanded snacks to fortify them. PRACTICAL APPLICATIONS This study determined that it is better to modify whey protein isolates (WPI) before adding them to the corn meal and extruding them to create crunchy products. The process described shows that modifying the structure of the whey proteins creates a form of WPI that is more compatible with corn meal. This knowledge allows the creation of nutritious high-protein expanded crunchy snacks. [source] Effects of shear and electrical properties on flow characteristics of pharmaceutical blendsAICHE JOURNAL, Issue 3 2010Kalyana C. Pingali Abstract This article examines the effects and interactions of shear rate, shear strain on electrical and flow properties of pharmaceutical blends. An unexpectedly strong relation between the flow and passive electrical properties of powders is observed to depend on the shear history of the powder bed. Charge density, impedance, dielectrophoresis, flow index, and dilation were measured for several pharmaceutical blends after they were subjected to a controlled shear environment. It was found that the increase in the shear strain intensified the electrical properties for blends that did not contain MgSt. The opposite effect was found in blends lubricated with MgSt. Different shear conditions resulted in different correlations between flow index and dilation. Flow properties of powders were found to improve with continuous exposure to shear strain. It was also found that flow properties correlated to charge acquisition and impedance for different shear treatments. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Two novel monoclonal antibodies to VWFA3 inhibit VWF-collagen and VWF-platelet interactionsJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 9 2007Y. ZHAO Summary.,Background:,The interaction of collagen-von Willebrand factor (VWF)-GPIb is essential for platelet adhesion, especially under high shear conditions. VWF, which acts as a bridge between platelets and exposed subendothelium, interacts with collagen through its A3 domain, which is a new target for the antithrombotic agent. Objective:,To develop functional blockers that specifically inhibit VWF-dependent adhesion of platelets to collagen under high shear stress. Methods:,To develop murine antihuman VWF A3 monoclonal antibodies (mAbs) by standard hybridoma technology, and characterize their abilities to block interactions between VWF A3 and collagen as well as platelet function. Results:,Thirty anti-VWF-A3 mAbs were obtained. Among them, two mAbs, designated as SZ-123 and SZ-125, were found to inhibit VWF-collagen type III interaction. SZ-123 and SZ-125 inhibited the binding of purified human VWF (1.5 or 3 ,g mL,1) to human placenta collagen type III (IC50 = 0.07 ± 0.02 and 0.15 ± 0.03 ,g mL,1, respectively) or to calf skin collagen type III (IC50 = 0.48 ± 0.06 and 0.51 ± 0.07 ,g mL,1, respectively) coated on plates. Under flow shear condition (1000 s,1), SZ-123 and SZ-125 inhibited platelet adhesion on human placenta collagen- or calf skin collagen-coated surfaces. Both mAbs also inhibited platelet aggregation induced by ristocetin, botrocetin or bovine plasma. Conclusions:,SZ-123 and SZ-125 inhibited VWF-collagen and VWF-platelet interactions. [source] The von Willebrand factor self-association is modulated by a multiple domain interactionJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 3 2005H. ULRICHTS Summary.,Background:,Platelet adhesion and aggregation at sites of vascular injury exposed to rapid blood flow require von Willebrand factor (VWF). VWF becomes immobilized by binding to subendothelial components or by a self-association at the interface of soluble and surface-bound VWF. Objectives:,As this self-association has been demonstrated only under shear conditions, our first goal was to determine whether the same interaction could be observed under static conditions. Furthermore, we wanted to identify VWF domain(s) important for this self-association. Results:,Biotinylated VWF (b-VWF) interacted dose-dependently and specifically with immobilized VWF in an enzyme-linked immunosorbent assay (ELISA) assay, showing that shear is not necessary to induce the VWF self-association. Whereas anti-VWF monoclonal antibodies (mAbs) had no effect on the self-association, the proteolytic VWF-fragments SpII(1366,2050) and SpIII(1,1365) inhibited the b-VWF,VWF interaction by 70 and 80%, respectively. Moreover, a specific binding of b-VWF to immobilized Sp-fragments was demonstrated. Finally, both biotinylated SpII and SpIII were able to bind specifically to both immobilized SpII and SpIII. Similar results were observed under flow conditions, which confirmed the functional relevance of our ELISA system. Conclusion:,We have developed an ELISA binding assay in which a specific VWF self-association under static conditions can be demonstrated. Our results suggest a multiple domain interaction between immobilized and soluble VWF. [source] An experimental study of morphology and rheology of ternary Pglass-PS-LDPE hybridsPOLYMER ENGINEERING & SCIENCE, Issue 6 2003Peter C. Guschl Ternary blends of low-density polyethylene (LDPE), polystyrene (PS), and a low Tg tin-based phosphate glass (Pglass) were prepared at compositions ranging from 0,50 vol% Pglass in which either LDPE or PS was the continuous matrix phase. Differential scanning calorimetry was used to investigate the phase behavior of the pure components, PS-LDPE blends and binary Pglass-polymer hybrids. Interesting steady-shear and transient rheology was observed for the hybrids. In particular, the steady shear viscosity curves for the hybrids of ,Pglass , 30% exhibited unusual, four-region flow behavior, similar to that of liquid crystalline polymers. Two Newtonian plateaus at low ( , 0.1 s,1) and moderate (0.4 , , s,1) shear rates connected by two distinct shear-thinning regimes were apparent. This observed rheology is ascribed to a unique composite morphology of these multi-component systems. Rheological data on the binary Pglass-polymer systems suggest that the presence of the Pglass within both PS and LDSE contributes significantly to this unusual behavior, perhaps because of the interfacial behavior between the phases. Micrographs obtained via scanning electron microscopy reveal preferential placement of the Pglass phase dispersed within the PS-phase and surrounding the LDPE phase. Optical shearing data confirmed the evolution of this microstructure under specific shear conditions. [source] Factors influencing antibody stability at solid,liquid interfaces in a high shear environmentBIOTECHNOLOGY PROGRESS, Issue 5 2009James G. Biddlecombe Abstract A rotating disk shear device was used to study the effect of interfacial shear on the structural integrity of human monoclonal antibodies of IgG4 isotype. Factors associated with the solution conditions (pH, ionic strength, surfactant concentration, temperature) and the interface (surface roughness) were studied for their effect on the rate of IgG4 monomer loss under high shear conditions. The structural integrity of the IgG4 was probed after exposure to interfacial shear effects by SDS-PAGE, IEF, dynamic light scattering, and peptide mapping by LC-MS. This analysis revealed that the main denaturation pathway of IgG4 exposed to these effects was the formation of large insoluble aggregates. Soluble aggregation, breakdown in primary structure, and chemical modifications were not detected. The dominant factors found to affect the rate of IgG4 monomer loss under interfacial shear conditions were found to be pH and the nanometer-scale surface roughness associated with the solid-liquid interface. Interestingly, temperature was not found to be a significant factor in the range tested (15,45°C). The addition of surfactant was found to have a significant stabilizing effect at concentrations up to 0.02% (w/v). Implications of these findings for the bioprocessing of this class of therapeutic protein are briefly discussed. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] | ||||||||||