bluuebunny/crossref_metadata_2025_split huggingface dataset:
Managing environmental aspects associated with the development of domestic and international power projects
Authors: Stover‐Catha Peggy , Edgley Gerald , Cooper Laura 
Published: February 2007

AbstractIncreasingly, a key component in the financial success of developing and operating domestic and international energy projects is the management of environmental issues. This article outlines an environmental management system for developing and acquiring power projects. The specific issues addressed include the development and communication of an environmental policy and the development and use of environmental expectations. These expectations are designed to manage the environmental components of the dynamic development process and provide a framework for enhancing team effectiveness in addressing environmental issues. Examples of expectations for each development phase are provided. © 1998 John Wiley & Sons, Inc.
Renewable energy: Biomass power and biofuels as alternative sustainable energy sources
Authors: Kolar Jim 
Published: February 2007

AbstractThis article describes biomass fuels as renewable and sustainable energy resources in Minnesota as well as across the United States. This country has long benefited from surplus supplies of diverse energy resources, while our dependency on foreign petroleum supplies and domestic coal reserves has only recently prompted Congress to recognize the importance of renewable and alternative fuels such as biomass energy. Our further utilization of biomass power and biofuels can be an important step in altering our dependency on both coal and petroleum while simultaneously reducing carbon dioxide emissions. © 1998 John Wiley & Sons, Inc.
Solving variational problems in image processing via projections – a common view on TV denoising and wavelet shrinkage
Authors: Lorenz D.A. 
Published: February 2007

AbstractIn this paper we investigate a special class of minimization problems for image denoising and deblurring. We focus on problems with positively one homogeneous penalty terms and show that the minimizer can be given in terms of projections. Especially we apply the results to wavelet shrinkage and TV denoising. Furthermore we present an application to deblurring with a TV penalty term. The approach presented here provides a common view on TV denoising and wavelet shrinkage.
Studies on the selectivity of enzymes involved in platelet‐activating factor formation in stimulated cells
Authors: van den Bosch H. , Sturk A. , ten Cate J. W. , Aarsman A. J. 
Published: February 2007

AbstractThe present studies were undertaken to obtain further insight into the selectivities of the enzymes, i.e., phospholipase A2 and acetyltransferase, involved in platelet‐activating factor (PAF) production upon stimulation of human polymorphonuclear leukocytes (PMN) and platelets. After appropriate stimulation of the cells in the presence of [3H]acetate the total PAF and analogs, i.e., 1‐alkyl‐2‐acetyl‐, 1‐alkenyl‐2‐acetyl‐, and 1‐acyl‐2‐acetyl‐glycero‐3‐phosphocholine were isolated by high performance liquid chromatography. The isolated mixture was subjected to treatment with phospholipase A1 to differentiate acetate incorporation into 1‐ether linked and 1‐ester linked species. The ratio of acetate incorporation into 1‐ether linked vs 1‐ester linked PAF analogs amounted to 13.8±1.0 and 1.3±0.1 for PMN and platelets, respectively. When compared to the ratio of 1‐ether linked and 1‐ester linked species in the diradylglycerophosphocholine precursors in each cell type, i.e., 1.13 for PMN and 0.22 for platelets, these data suggested a pronounced selectivity for the phospholipase A2 and/or acetyltransferase in the process of PAF production. When the experiments were repeated with cells that had been pretreated with phenylmethanesulfonylfluoride (PMSF) to block the acetylhydrolase, the most dramatic effects were observed on acetate incorporation into 1‐acyl‐2‐acetyl‐glycero‐3‐phosphocholine, which increased much more than that into 1‐alk(en)yl‐2‐acetyl‐glycero‐3‐phosphocholine. Under these conditions, the ratio of acetate incorporation into 1‐ether linked vs 1‐ester linked PAF analogs became 1.4±0.2 and 0.17±0.02 for PMN and platelets, respectively. These values are very close to the 1‐ether linked vs 1‐ester linked species in the diradylglycerophosphocholine precursors for PAF in the respective cell type. These data suggested that the selectivities of phospholipase A2 and/or acetyl transferase for etherlinked species, as observed in non‐PMSF treated cells, are only apparent and caused by rapid degradation of the 1‐acyl analog either before or after acetylation. In line with this interpretation, we demonstrated that 1‐acyl‐2‐acetyl‐GPC can be deacylated to water‐soluble acetyl‐GPC and GPC by sonicated PMN and platelets and that this deacylation is completely blocked in sonicates from PMSF‐pretreated cells. In addition, evidence is presented which indicates that the enzyme responsible for deacylation may be a lysophospholipase.
Transmembrane signalling and paf‐acether biosynthesis
Authors: Ninio Ewa , Joly Francine 
Published: February 2007

AbstractExpression of lyso paf‐acether (lyso paf):acetyl‐CoA acetyltransferase and its activation above basal levels by specific agonists controls the rate of paf biosynthesis in proinflammatory cells. Acetyltransferase activation in these cells is due to the rapid postranslational modification of an inactive precursor by phosphorylation, most probably catalyzed by a cAMP‐dependent kinase. However, the possibility exists that a calcium/calmodulin‐dependent kinase can be implicated as well. Unlike murine cultured mast cells, human neutrophils form paf when stimulated with phorbol myristate acetate (PMA) or diacylglycerol. In both cell types, acetyltransferase is activated by PMA. Controversy exists as to whether PMA activates the remodeling pathway,i.e. the activation of phospholipase A2 and acetyltransferase, or thede novo route through CDPcholine cholinephosphotransferase action on alkylacetylglycerol. There is some indication that PKC might regulate paf biosynthesis. The implication of a GTP‐regulated protein has also been postulated in signal transduction leading to paf formation in endothelial cells, neutrophils, and mast cells. The topography of paf formation is discussed in light of the subcellular distribution of acetyltransferase in neutrophils and Krebs II cells.
Biotransformation of alkylglycerols in plant cell cultures: Production of platelet activating factor and other biologically active ether lipids,
Authors: Mangold Helmut K. , Apte Shashank S. , Weber Nikolaus 
Published: February 2007

AbstractPlant cells in culture are capable of incorporating exogenous 1‐O‐alkyl‐sn‐glycerols into various neutral and ionic ether lipids. 1‐O‐Alkyl‐2‐acyl‐sn‐glycerol‐3‐phosphocholines, the major class of compounds thus formed, are used for the preparation of platelet activating factor (PAF) in high yields. Similarly, the prochiral 2‐O‐alkyl‐sn‐glycerols are transformed to chiral 2‐O‐alkyl glycerophospholipids from which compounds can be obtained that exhibit antiviral activity in plant and animal cells. Reaction of 1‐O‐alkyl‐2‐acyl‐sn‐glycerol‐3‐phosphocholines with phospholipase D in the presence of ethanolamine leads to 1‐O‐alkyl‐2‐acyl‐sn‐glycerol‐3‐phosphoethanolamines, which serve as starting material, for the preparation of 1‐O‐alkyl‐2‐acyl‐sn‐glycero‐3‐phospho‐(N‐acyl)ethanolamines, compounds known to have antitumor activity.
Effect of platelet‐activating factor on lipoprotein lipase and blood lipids
Authors: Mimura Keiji , Yukawa Susumu , Mori Yoshio , Okada Kazuya , Mune Masatoshi , Nishikawa Osamu , Hibino Akira , Sonobe Miyahiko , Goto Tetuya , Nomoto Hiroshi 
Published: February 2007

AbstractWe investigated the effect of platelet‐activating factor (PAF) and of the PAF specific antagonist CV‐6209 on plasma lipid metabolism, and particularly on post‐heparin plasma lipolytic activity in male Wistar rats. Lipoprotein lipase (LPL) activity was enhanced by intravenous injection of PAF before intravenous injection of heparin when the PAF dose was low (0.2 μg/kg). PAF activated hepatic triacylglycerol lipase (HTGL) activity dose‐dependently. Plasma triacylglycerols (TG) significantly decreased with the activation of LPL and/or HTGL. Plasma total cholesterol (TC) and phospholipid (PL) levels decreased at a low dose of PAF (0.2 μg/kg), but increased when higher doses were used. The PAF antagonist CV‐6209 partially reversed the PAF induced effects on HTGL, TC and PL.
Tandem mass spectrometry of negative ions from choline phospholipid molecular species related to platelet activating factor
Authors: Zirrolli J. A. , Clay K. L. , Murphy R. C. 
Published: February 2007

AbstractFast atom bombardment mass spectrometry of choline phospholipids produces negative ions characteristic of the intact molecule and tandem mass spectrometry of collision‐induced decomposition of M‐15 anions characterizes both the identity and substituent position of radyl groups. Certain choline phospholipid molecular species which may be of special interest in the generation of platelet activating factor contain a highly unsaturated fatty acyl substituent atsn‐2 and an ether radyl group atsn‐1; other choline phospholipid molecular species which contain esterified arachidonic acid are of interest as potential sources of arachidonate for eicosanoid biosynthesis. Collisional activated decomposition of 1‐hexadecanoyl‐2‐arachidonoyl‐sn‐glycerophosphocholine produce abundant carboxylate anions atm/z 303 (arachidonate) andm/z 255 (hexadecanoate) in a ratio of 3∶1, diagnostic for thesn‐2 arachidonoyl position. The ether analog, 1‐O‐hexadecyl‐2‐arachidonoyl glycerophosphocholine, produces only one collision‐induced dissociation ion atm/z 303 and no product ions corresponding to the ether substituent atsn‐1. Molecular weight information from the M‐15 ion combined with the CID generated carboxylate anions completely characterize these important phospholipids.Precursor ion studies of M‐15 anions from glycerophosphocholine lipids indicate that this ion is derived directly from a unique adduct ion formed by attachment of the molecular species to a matrix alkoxide ion, neutralizing the positive charge of the quaternary choline nitrogen. Decomposition of this adduct ion yields a methylated matrix molecule and the nominal M‐15 ion.
Chemical and biochemical characterization of lignan analogs as novel PAF receptor antagonists
Authors: Shen T. Y. 
Published: February 2007

AbstractVarious derivatives and isosteres of neolignans of the 2,5‐diaryl tetrahydrofuran type have been synthesized as antagonists of platelet‐activating factor (PAF). A detailed analysis of their structure‐activity relationship (SAR) has revealed a clear preference for an asymmetrical molecular configuration with a high degree of stereo and chiral specificity associated with greater potency. Thetrans‐2S,5S enantiomers are generally 10–200 times more potentin vitro than their correspondingcis ortrans‐2R,5R isomers. A similar stereochemical preference is indicated by the recently reported PAF antagonist MK‐287 which has undergone clinical evaluation. An azido derivative L‐662,025 has been characterized as a photolabile irreversible antagonist of PAF for the investigation of solubilized and partially purified PAF binding proteins from cell membranes. The biological justification for concomitant inhibition of both PAF receptor and 5‐lipoxygenase in inflammation is well recognized. The feasibility of developing such dual‐functional agents has been demonstrated by a group of dithiolane analogs of neolignans and several derivatives of futoenone.
Studies on the role of platelet‐activating factor in blood pressure regulation
Authors: Sakaguchi Katsuhiko , Morimoto Shigeto , Masugi Fuminori , Saeki Shuichi , Ogihara Toshio , Yamada Kouji , Yamatsu Isao 
Published: February 2007

AbstractCirculating levels of 1‐O‐hexadecyl‐2‐acetyl‐sn‐glycero‐3‐phosphocholine (C16PAF) in human subjects were measured by gas chromatography/mass spectrometry using negative ion chemical ionization. The mean (±S.D.) circulating C16PAF levels in patients with essential hypertension (18.1±5.3 pg/mL, n=16) were not significantly different from those in normotensive subjects (17.2±7.2 pg/mL, n=14). During a salt balance study, high salt intake (20 g/day) significantly increased the circulating level of C16PAF, and changes in circulating C16PAF significantly and positively correlated with changes in mean arterial blood pressure (r=0.47, p<0.05). Changes in C16PAF also correlated with changes in creatinine clearance (r=0.55, p<0.05), but did not correlate with changes in plasma sodium concentration, plasma chloride concentration and plasma volume. An intravenous injection of 50 μg of human atrial natriuretic peptide (hANP) decreased circulating C16PAF levels from 20.0±2.7 to 13.9±2.4 pg/mL of blood (n=10, p<0.01) in healthy subjects. The data appear to indicate that C16PAF levels are changed by salt intake‐induced mild increase in blood pressure, and that hANP may be an endogenous factor which lowers circulating C16PAF.
The effects of R‐75,317 on antiglomerular basement membrane glomerulonephritis in rats
Authors: Miyamoto Masaaki , Koike Hiroyuki , Sada Toshio , Ijima Yasuteru , Fukushige Junichiro , Nakamura Norio 
Published: February 2007

AbstractPlatelet‐activating factor (PAF) is a potent inflammatory mediator which is released by various inflammatory cells and produced by certain tissues, including the kidney. PAF has been shown to increase glomerular permeability to protein and to decrease glomerular filtration rate (GFR) by contracting mesangium. On the basis of these observations, it has been suspected that PAF may play a role as mediator of glomerular damage in glomerular nephritis. To examine this possibility, we studied the effects of a specific PAF antagonist, R‐75,317, on the development of an experimental model of anti‐glomerular basement membrane (anti‐GBM) glomerulonephritis. Glomerulonephritis was initiated by injecting rabbit anti‐rat GBM serum into rats. Proteinuria gradually developed after serum injection, plateaued at week 2, and remained at the high level of week 2 throughout the experimental period (6 wk). Chronic treatment with R‐75,317 (10 mg/kg/day i.p.) tended to delay the onset of proteinuria and significantly accelerated the recovery phase. Creatinine clearance (Ccr) fell to 40% at week 3. R‐75,317 treatment completely prevented this decline of Ccr. Histological changes in this model (glomerular hypertrophy, proliferation of mesangial matrix and interstitial fibrosis) were also ameliorated by the R‐75,317 treatment. The results suggest that PAF may play a role in the development of glomerulonephritis and that PAF antagonists could be used in the treatment of human renal disease.
Platelet‐activating factor may mediate dexamethasone‐induced gastric damage in the rat
Authors: Filep János , Hermán Ferenc , Braquet Pierre 
Published: February 2007

AbstractThe possible role of platelet‐activating factor (PAF) in dexamethasone‐induced gastric mucosal damage was studied in rats. PAF was measured by a platelet aggregation assay. The identity of the PAF‐like product recovered from gastric tissues was ascertained by thin‐layer chromatography and high‐pressure liquid chromatography. Low levels of PAF were detected in the normal rat stomach, while in dexamethasone‐treated animals PAF levels were significantly higher. Pretreatment of the animals with BN 52021, a specific PAF receptor antagonist, significantly attenuated dexamethasone‐induced mucosal injury. These findings suggest that PAF may be a mediator of mucosal damage induced by glucocorticoids.
Stereospecific synthesis of antitumor active thioether PAF analogs
Authors: Bhatia Suresh K. , Hajdu Joseph 
Published: February 2007

AbstractA novel stereospecific synthesis of antitumor active thioether analogs of platelet‐activating factor (PAF) is reported. The synthesis is based upon: i) the use ofD‐serine to provide the chiral center for the construction of the optically active phospholipid molecule; ii) development of thesn‐1‐thioalkyl function via thioacetate displacement of methanesulfonate‐activated primary hydroxyl group followed by alkylation of thesn‐1‐thiolate function; and iii) introduction of the phosphocholine moiety through the 2‐chloro‐2‐oxo‐1,3,2‐dioxaphospholane/trimethylamine sequence. The entire scheme relies on the use of a single protecting group. The synthetic thioether phospholipid 1‐S‐hexadecyl‐2‐N‐acetamidodeoxy‐sn‐glycero‐3‐phosphocholine has been shown to be a potent antitumor active phospholipid, exhibiting tumor cytotoxicity against a lymphoblastoid lymphoma (Li‐A) cell line and a malignant histiocytic (DHL‐4) cell line of human origin at the same level of potency as ET‐18‐OMe and 1‐O‐octadecyl‐2‐N‐acetamidodeoxy‐sn‐glycero‐3‐phosphocholine. The synthetic method described has a great deal of flexibility, providing a convenient general route to a wide range of thioether PAF analogs.
Helichrysum see oil. I. Separation and characterization of individual acids
Authors: Powell R. G. , Smith C. R. , Wolff I. A. 
Published: February 2007

AbstractHelichrysum bracteatum (family Compositae) seed oil contains a complex array of unusual fatty acids in addition to the usual palmitic, stearic, oleic, and linoleic acids. Its unusual constituents include 9.5% crepenynic acid; 14.0% epoxy acids, mainly coronaric; 4.4%cis,trans‐hydroxy conjugated dienoic acids; and 7.2% of a previously unknown hydroxyacetylenic acid for which the name helenynolic acid is proposed. A method for determining helenynolic acid in the presence of hydroxy‐conjugated dienes is described.
Cyclopropenoid fatty acid content and fatty acid composition of crude cottonseed oils from successive solvent extractions
Authors: Bailey A. V. , Pons W. A. , Skau E. L. 
Published: February 2007

AbstractThe fatty acid composition and properties of six fractions of oil successively extracted from cottonseed meats has been investigated. The cyclopropenoid fatty acid concn increased regularly from 0.30舑1.06%, a 3.5‐fold increase. This suggests that the cyclopropenoid constituents of the oil in the seed are less accessible to the solvent. The linoleic acid concn decreased from 56.3舑53.1% accounting for a slight reduction in iodine value (I.V.). The first two fractions had a markedly lower phosphatide content than the remaining fractions.
Evaluating detergents by a huck towel method
Authors: Mihalik W. B. , Cross H. D. 
Published: February 2007

AbstractThis paper describes a practical method of evaluating the performance of detergents by using huck towels soiled in plant mechanical shops and washed in a 5 gal semiautomatic washer. Detergency, redeposition and optical brightener intensity are evaluated by reflectance, yellowness, blueness and ultraviolet fluorescence measured on a Gardner Larger Area Colorimeter after six soil‐wash cycles. The precision of the method is determined statistically by analysis of variance. Significant differences to a 95% confidence level that can be expected by this method are given.
Modern techniques for the production of crude tall oil
Authors: Thrush R. E. 
Published: February 2007

AbstractA short background of the methods for the production of crude tall oil is given.A simplified flow sheet of the continuous acidulation proces is shown and a new type centrifuge is introduced for the continuous separation of the various components of the acidulated sulfate reaction mixture.The separation section of the process is described with particular emphasis given to the operation of the centrifuge.Performance of the process is discussed with respect to yield and quality of the crude tall oil.
Tall oil fatty acid‐formaldehyde derivatives and their application as vinyl plasticizers
Authors: DiBella E. P. , Green Richard , Kraft W. M. , Gottesman R. T. 
Published: February 2007

AbstractAcid‐catalyzed condensations of tall oil fatty acid and related materials with formaldehyde, in the absence of a carboxylic acid solvent, led to acidic products, lower in unsaturation, but partially polymeric due to formation of interester linkages. Hydrolysis of these linkages furnished products lower in mol wt but higher in free hydroxyl content. Some modified esters of these materials were evaluated as primary plasticizers for polyvinyl chloride by comparison with dioctyl phthalate and, when applicable, to Monsanto S409.In general, those plasticizer candidates in which free hydroxyl contents were lowered by acetylation exhibited a good overall balance of physical and permanence properties but possessed poor heat stability and borderline compatibility.A preliminary study on the acid‐catalyzed reaction of ethyl tallate with anhydrous formaldehyde gave promise that an improved alternate route to fatty acid‐formaldehyde esters could be developed.
Omega‐formylalkanoates by ozonization of unsaturated fatty esters
Authors: Anders D. E. , Pryde E. H. , Cowan J. C. 
Published: February 2007

AbstractOzonization of the methyl esters of 11‐eicosenoic, linoleic, erucic and linolenic acids gave a number of different homologous methyl ३‐formylalkanoates. Complete ozonization of the monounsaturated esters formed C11 and C13 compounds with 90% conversion; partial ozonization of the polyunsaturated esters gave C12 and C15 products with maximum conversions at ca. 75% consumption of fatty ester. Thus, methyl linoleate gave 52 and 23% conversions to the 9‐ and 12‐carbon products, and methyl linolenate gave 29, 27 and 19% conversions to the 9‐, 12‐ and 15‐carbon products. Yields of aldehyde or acetal esters in distilled products were 70舑90% in preparative‐scale experiments. Kinetic analysis showed that ozone attack was essentially random. Methanol was used as a participating solvent.
Quantitative measure of selectivity of hydrogenation of triglycerides
Authors: Albright L. F. 
Published: February 2007

AbstractGraphs have been prepared using a digital computer that allow the quantitative determination of the degree of selectivity for the hydrogenation of cottonseed, peanut, corn, soybean and linseed oils. Use of these graphs requires only a knowledge of the composition of the initial (unhydrogenated) oil and that of the hydrogenated oil plus simple calculations. If the exact composition of the initial oil is unknown, a typical composition can generally be assumed.
Polyunsaturated phosphatidylinositol and diacylglycerol substantially modify the fluidity and polymorphism of biomembranes: A solid‐state deuterium NMR study
Authors: Larijani Banafshé , Dufourc Erick J. 
Published: February 2007

AbstractOne of the main biological systems that can be used as a model for studying the molecular mechanisms involved in membrane fusion is the formation of the nuclear envelope (NE). NE assembly to form the male pronucleus at fertilization occurs by binding of NE membrane precursor vesicles to chromatin and their fusion. MV1 is an NE precursor vesicle population of low density, highly enriched in {18∶0/20∶4}Pl. The modification of {18∶0/20∶4}Pl to {18∶0/20∶4}DAG leads to NE formation, and the depletion of MV1 from the total membrane precursors results in the inhibition of NE assembly. Here we show by2H NMR studies of various physiologically relevant model membranes made of {18∶0/20∶4}Pl, {18∶0/20∶4}DAG, and saturated and unsaturated PC that membranes of composition similar to MV1 exhibit dramatically enhanced fluidity and non‐lamellar structures, thus providing a possible explanation for the essential role of MV1 and the modification of Pl to DAG in membrane precursor vesicles during NE assembly.