Transport of amino acid aryl amides by the intestinal H+/peptide cotransport system, PEPT1

The oxygen tension (PO2) in the renal cortex and outer renal medulla in 26 rats was studied by use of oxygen microelectrodes before and after injection of x-ray contrast media (CM). The CM, iopromide, ioxaglate and iotrolan were administrated intravenously in iodine equivalent doses (1,600 mg iodine/kg body wt). Ringer's solution was used as the control. In the outer medulla, all three CM induced a decrease in PO2: iopromide (N = 6) from 30 +/- 3 to 18 +/- 4 mm Hg; ioxaglate (N = 7) from 32 +/- 6 to 15 +/- 4 mm Hg; and iotrolan (N = 6) from 36 +/- 3 to 14 +/- 4 mm Hg. All these decreases were significant. After the injection of Ringer's (N = 7) there was an increase from 34 +/- 3 to 35 +/- 3 mm Hg. In the cortex a slight decrease was noted for injection of CM, but this was significant only after injection of iotrolan. All tested contrast media decrease PO2 in the outer renal medulla, which may partly explain contrast medium-induced acute renal failure.     

pH-dependent fluoride transport in intestinal brush border membrane vesicles

Ciliary neurotrophic factor (CNTF) exerts a multiplicity of effects on a broad spectrum of target cells, including retinal neurons. To investigate how this functional complexity relates to the regulation of CNTF receptor alpha (CNTFR alpha) expression, we have studied the developmental expression of the receptor protein in chick retina by using immunocytochemistry. During the course of development, the receptor is expressed in all retinal layers, but three levels of specificity can be observed. First, the expression is regulated temporally with immunoreactivity observed in ganglion cells (embryonic day 8 [E8] to adult), photoreceptor precursors (E8-E12), amacrine cells (E10 to adult), bipolar cells (E12-E18), differentiated rods (E18 to adult), and horizontal cells (adult). Second, expression is restricted to distinct subpopulations of principal retinal neurons: preferentially, large ganglion cells; subpopulations of amacrine cells, including a particular type of cholinergic neuron; a distinctly located type of bipolar cell; and rod photoreceptors. Third, expression exhibits subcellular restriction: it is confined largely to dendrites in mature amacrine cells and is restricted entirely to outer segments in mature rods. These data correlate with CNTF effects on the survival of ganglion cells and mature photoreceptors, the in vitro differentiation of photoreceptor precursors and cholinergic amacrine cells, and the number of bipolar cells in culture described here or in previous studies. Thus, our results demonstrate an exceptional degree of complexity with respect to the regulation of neuronal CNTFR alpha expression in a defined model system. This suggests that the same signaling pathway is used to mediate a variety of regulatory influences, depending on the developmental stage and cell type.     

An epistemic event‐based correlation approach for managing pervasive networks

Existing pervasive applications are based on time series data that possess the form of time‐ordered series of events. Such applications also embody the need to handle large volumes of unexpected events, often modified on‐the‐fly, containing conflicting information, and dealing with rapidly changing contexts while producing results with low latency. Correlating events across contextual dimensions holds the key to expanding the capabilities and improving the performance of these applications. In this paper we analyze complex‐event semantic correlation that examines epistemic uncertainty in computer networks by using Dempster–Shafer theory to support a high‐volume, event‐based, in‐network and non‐deterministic pervasive network management. We consider imprecision and uncertainty when an event is detected and associate a belief parameter with the semantics and the detection of composite events. The approach taps into in‐network processing capabilities of pervasive computer networks and can withstand missing or conflicting information gathered from multiple participating entities. In the end, we establish that a lightweight, distributed, large‐volume, event‐based technique which exploits epistemic uncertainty to correlate events along contextual dimensions provides a successful technique for enabling management of large‐scale and pervasive contemporary and future computer networks. Copyright © 2011 John Wiley & Sons, Ltd.     

Performance optimization of Jatropha biodiesel engine model using Taguchi approach

This paper proposes a methodology for thermodynamic model analysis of Jatropha biodiesel engine in combination with Taguchi’s optimization approach to determine the optimum engine design and operating parameters. A thermodynamic model based on two-zone Weibe’s heat release function has been employed to simulate the Jatropha biodiesel engine performance. Among the important engine design and operating parameters 10 critical parameters were selected assuming interactions between the pair of parameters. Using linear graph theory and Taguchi method an L₁₆ orthogonal array has been utilized to determine the engine test trials layout. In order to maximize the performance of Jatropha biodiesel engine the signal to noise ratio (SNR) related to higher-the-better (HTB) quality characteristics has been used. The present methodology correctly predicted the compression ratio, Weibe’s heat release constants and combustion zone duration as the critical parameters that affect the performance of the engine compared to other parameters.     

Preparation and characterization of pyrolytic oil through pyrolysis of neem seed and study of performance,combustion and emission characteristics in CI engine

This paper deals with production of pyrolytic oil from neem seed and using this pyrolytic oil in the form of blend with fossil diesel to study the performance and emission characteristics in CI engine. Thermal and catalytic pyrolysis of non edible neem seed was performed in a slow fixed bed pyrolyser to produce pyrolytic oil. Maximum pyrolytic oil obtained in thermal pyrolysis was 55% wt and in catalytic pyrolysis was 60% wt using both Al₂O₃ and K₂CO₃ catalysts followed by 41% wt and 38% wt for zeolite and kaolin catalysts respectively. The catalytic pyrolysis improved pH and calorific values of 12.4% and 14.4% respectively as compared to thermal pyrolysis. Blends of neem seed catalytic pyrolytic oil (NB) with fossil diesel in the ratio of 5% (NB5) and 10% (NB10) by volume were tested on an unmodified CI engine. Brake thermal efficiency (BTE) was lower at part load conditions and higher at full load condition up to 3.7% in the case of blends as compared to fossil diesel operation. Higher Brake Specific Fuel Consumption (BSFC) was observed in the case of NB5 blend on all load conditions, up to 23.9%. Reduction in emission levels were observed for HC (46.9%), CO (42.2%), CO₂ (29.8%) and NOx (20.7%) at full load condition. This study observed that neem seed catalytic pyrolytic oil is a potential renewable and sustainable green fuel.     

Aging of vulcanizates of formulations for rubber seals

Typical formulations based on NBR (acrylonitrile butadiene rubber), EPDM (ethylene propylene diene monomer rubber), and a NBR–CR (polychloroprene rubber) blend were studied for various properties under accelerated air aging conditions. The trend in tensile properties indicated the propensity of these formulations to oxidative degradation. The derivatives of these properties, such as their retention indices, strain energy, and Mooney–Rivlin constants also showed similar trends. Some of the observations correlate to shelf-aging data, but the time to rupture data derived from ultimate elongation values did not provide tangible conclusions. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 985–994, 1998     

Epoxy-imide resins from <Emphasis Type="Italic">N</Emphasis>-(4-carboxyphenyl)trimellitimide: effect of imide and aromatic content on adhesive and thermal properties

The effect of imide and aromatic content on the adhesive and thermal properties of epoxy-imide resins obtained through the reaction of epoxy resins viz., Araldite GY 250 (DGEBA; difunctional), Araldite EPN 1138 (novolac; polyfunctional) and epoxidized hydroxyl-terminated polybutadiene (EHTPB) with an imide-diacid viz., N-(4-carboxyphenyl)trimellitimide (IDA-I) was studied for different carboxyl equivalent to epoxy equivalent ratios (C/E ratios). The glass transition temperature of epoxy-imides varies from 80 to 144 °C, 120 to 184 °C and 41 to 143 °C for GY 250-IDA-I, EPN 1138-IDA-I and EHTPB-IDA-I respectively with the variation in C/E ratio from 0.5 to 2. For C/E ratio up to 1, the overall thermal stability of epoxy-imides follow the trend, EPN 1138-IDA-I > GY 250-IDA-I > EHTPB-IDA-I and above this ratio considerable improvement in overall thermal stability is observed only for EHTPB-IDA-I. The optimum C/E ratio for obtaining maximum room temperature and elevated temperature adhesive strength was found to be 1.25. For the optimum ratio, GY 250, EPN 1138 and EHTPB-based systems give adhesive strength of 29, 23 and 18 MPa respectively at room temperature and retain 78.3, 56.2 and 44.4% of the room temperature adhesive strength at 150 °C. The influence of C/E ratio or in otherwords, imide or aromatic content on the adhesive strength, thermal stability and glass transition temperature was more pronounced for aliphatic epoxy, i.e., EHTPB-based system.     

Structural and optical properties of Ag doped tungsten oxide (WO<Subscript>3</Subscript>) by microwave-assisted chemical route

The present study explores, the pure and silver (Ag) doped WO₃ nanoparticles synthesized by microwave irradiation method. Powder X-ray diffraction results reveal that the WO₃ doped with Ag concentration from 0 to 10 wt% crystallizes in monoclinic structure. TEM analysis shows both pristine and silver doped WO₃ nanoparticles. They are having spherical morphology with a average size from 30 to 40 nm. Scanning electron microscopy studies depicts that both the pristine and Ag doped WO₃ form in spherical shaped morphology with an average diameter of 40–30 nm, which is in proper agreement with the average crystallite sizes calculated by Scherrer’s formula. A considerable red shift in the absorbing band edge and a decrease in the band gap energy from 3.00 to 2.85 eV for Ag doped samples were observed by using UV–DRS spectra analysis. The defects in crystal and oxygen deficiencies were analyzed by photoluminescence spectra analysis.