bluuebunny/crossref_metadata_2025_split huggingface dataset:
Formation and Crystal Structure of the Salt (IC(PPh3)2)2I[I3]·(I2)2 with a new Polyiodide Chain
Authors: Petz Wolfgang , Heimann Samuel , Öxler Florian , Neumüller Bernhard 
Published: February 2007

AbstractThe reaction of the carbodiphosphorane Ph3P=C=PPh3 (1) with MeI in the presence of iodine gives the oxidation product (IC(PPh3)2)2I[I3]·(I2)2 (2). In the solid state dimeric units linked by indefinite ···I−···I2···I3−···I2···I−··· chains are found. An additional I···I contact between the cation and the I2 molecule is formed, amounting to 359.23(5) pm. 2 crystallizes in the monoclinic space group P2/c, with the unit cell dimensions a = 2053.9(1), b = 1011.4(1), c = 1889.8(1) pm; β = 105.21(1)° and Z = 4.
Structural Investigations and Thermal Behaviour of Mercury(II) Sulfito Complexes
Authors: Weil Matthias , Breitinger Dietrich K. , Liehr Günther , Zürbig Jürgen 
Published: February 2007

AbstractThe crystal structures of (NH4)[HgSO3Cl] (1) and of (NH4)2[Hg(SO3)2] (2) were determined from single crystal diffractometer data sets. 1: 22 °C, Pnma, Z = 4, a = 15.430(3), b = 5.525(1), c = 6.679(1) Å, R(F) = 0.0256, Rw(F2) = 0.0642 (all 1056 unique reflections). 2: −108 °C, P212121, Z = 4, a = 6.2240(4), b = 9.3908(6), c = 13.6110(8) Å, R(F) = 0.0179, Rw(F2) = 0.0493 (all 2699 unique reflections). The structure of 1 contains bent Cl‐Hg‐SO3 entities (site symmetry m; d(Hg‐Cl) = 2.3403(13) Å, d(Hg‐S) = 2.3636(12) Å, ∠(Cl‐Hg‐S) = 164.51(5)°, d(S‐O) 2×1.458(3) Å, 1.468(4) Å, ${\bar d}\rm (S-O)$= 1.461Å) linked to undulated ribbons parallel to the b‐axis by intermolecular secondary bonds SO···Hg (d(O···Hg) = 2×2.595(3) Å). These ribbons in turn aggregate to layers around the bc‐plane. The layers are stacked along the a‐axis with interlayer distances of a/2. The structure of 2 is made up of O3S‐Hg‐SO3 moieties (d(Hg‐S) = 2.3935(7), 2.3935(8) Å; ∠(Hg‐S‐Hg) = 174.41(3)°; ${\bar d}\rm (S-O)$ = 1.474Å), that are linked to ribbons parallel to the a axis by coordination of Hg to three remote O atoms (2.801(4) < d(Hg‐O) < 2.844(3) Å). Adjacent ribbons are joined together by an additional Hg‐O contact of 2.733(3) Å, leading to a three‐dimensional anionic framework. Both crystal structures are stabilised by disordered NH4+ cations, placed between the anionic layers or in the vacancies of the framework, via moderate hydrogen bonding interactions N‐H···O with donor‐acceptor distances ranging from 2.8 to 3.2Å. 1 and 2 were further characterised by thermal analysis (TG, DSC). They start to decompose at temperatures above 130 °C.
Synthese und Kristallstruktur des Lewis‐Säure/Base‐Addukts AlCl3·C3N3Cl3
Authors: Tragl Sonja , Gibson Katharina , Meyer H.‐Jürgen 
Published: February 2007

AbstractSynthesis and Crystal Structure of the Lewis Acid‐Base Adduct AlCl3·C3N3Cl3The reaction between cyanuric chloride (C3N3Cl3) and the strong Lewis acid AlCl3 yielded colorless crystals of the adduct AlCl3·C3N3Cl3. The crystal structure was determined by single crystal X‐ray diffraction at room temperature and was solved in the space group $P{\bar1}$ with Z = 4, a = 7.3802(7) Å, b = 9.688(1) Å, c = 16.272(2) Å, α = 72.80(1)°, β = 89.97(1)°, γ = 87.23(1)°, and V = 1110.0(2) Å3. In the crystal structure, AlCl3 is closely associated to the triazine ring with Al–N distances of 2.042(3) Å and 2.067(4) Å, respectively. The AlCl3·C3N3Cl3 units are connected with each other via intermolecular N···Cl donor–acceptor interactions, forming tape‐like arrangements in the ac‐plane, with tapes running parallel to the a‐axis.
Inorganic‐organic Microporous Solid of Wells‐Dawson Type Polyoxometalate: Synthesis, Characterization, and Electrochemical Properties
Authors: Tian Aixiang , Han Zhangang , Peng Jun , Zhai Jiangli , Zhao Yulong 
Published: February 2007

AbstractAn inorganic‐organic hybrid solid (H6/5bppy)5[P2W18O62]·4.5H2O (1) (bppy = 4‐(5‐(4‐bromophenyl)pyridin‐2‐yl)pyridine) was hydrothermally synthesized by using pre‐constructed Wells‐Dawson type salt α‐K6P2W18O62·15H2O as inorganic moiety. The crystal structure keeps integrated and steady under the interactions together of aryl packing, hydrogen bonding and halogen bonding. X‐ray single crystal structure analysis reveals that compound 1 contains cavities with the sizes of about 6 × 8Å, in which H2O molecules are captured. The hybrid was used as a solid bulk modifier to fabricate a three‐dimensional bulk‐modified carbon paste electrode (1‐CPE) by direct mixing. The electrochemical and electrocatalytic behavior of the 1‐CPE has been studied in detail. The results exhibit that the redox ability of the Wells‐Dawson polyanions can be maintained in the hybrid solid, which has a good electrocatalytic activity toward the reduction of bromate and hydrogen peroxide. A hydrodynamic voltammetric experiment was performed to characterize the electrode as an amperometric sensor for the determination of hydrogen peroxide. The 1‐CPE showed long‐term stability and excellent reproducibility of surface renewal.
Chromatographic resolution of chiral diacylglycerol derivatives: Potential in the stereospecific analysis of triacyl‐sn‐glycerols
Authors: Laakso Paivi , Christie William W. 
Published: February 2007

AbstractDiacylglycerols have been separated as their (S)‐(+)‐or (R)‐(−)‐1‐(1‐naphthyl)ethyl urethanes by high performance liquid chromatography (HPLC) on a column of silica gel with 0.5% 2‐propanol in hexane as the mobile phase. The elution order of components derivatized with the (S)‐form of the reagent was 1,3‐, followed by 1,2‐, and finally 2,3‐diacyl‐sn‐glycerols. The elution order of 1,2‐ and 2,3‐diastereomers was reversed when the (R)‐form of 1‐(1‐naphthyl)ethyl isocyanate was used for derivatization. Single‐acid 1,2‐ and 2,3‐diastereomers were separated to the baseline with a resolution factor from 5.2–5.7, and the resolution factor between 1,3‐ and 1,2‐ or 2,3‐diacyl‐sn‐glycerol derivatives was more than 23. Molecular species of single‐acid diacylglycerol derivatives were separated in the sequence 18∶1<18∶0<18∶2<16.0.In order to assess this methodology as part of a procedure for the stereospecific analysis of triacyl‐sn‐glycerols, we prepared diacyl‐rac‐glycerols from maize oil, evening primrose oil and egg yolk triacylglycerols by partial hydrolysis with ethyl magnesium bromide. The 1,3‐, 1,2‐ and 2,3‐diacyl‐sn‐glycerols as (S)‐(+)‐1‐(1‐naphthyl)ethyl urethanes were isolated and their fatty acid compositions were determined. Although this only permitted an indirect determination of the compositions of positionssn‐1,‐2 and‐3, it was sufficient to indicate the potential of the methodology because results comparable to those published earlier were achieved.
Δ6 desaturase in brain and liver during development and aging
Authors: Bourre J. M. , Piciotti M. , Dumont O. 
Published: February 2007

AbstractΔ6 Desaturase was measured in the mouse brain and liver using linoleic acid as substrate. During pre‐ and postnatal development, Δ6 desaturase in brain decreased dramatically (12‐fold) up to postnatal day 21 and remained nearly constant thereafter. In liver, the activity increased approximately 9‐fold between day 3 before birth and day 7 after birth. Then it decreased slightly up to weaning and was approximately constant up to 4 mo. From then on, Δ6 desaturase decreased with age (40% between 4 and 17 mo).
The effect of glutathione on the vitamin E requirement for inhibition of liver microsomal lipid peroxidation
Authors: Leedle R. A. , Aust S. D. 
Published: February 2007

AbstractVitamin E dependent inhibition of rat liver microsomal lipid peroxidation in an NADPH and ADP‐Fe+3 containing system occurred at lower vitamin E concentrations in the presence of glutathione (GSH). Using microsomes from rats fed a vitamin E deficient diet, vitamin E was shown to be rquired for inhibition. Inhibition also required the presence of a storage labile microsomal component, since no inhibition was observed when using microsomes that had been stored for one moth. This observation provides evidence that direct reduction of reversibly oxidized vitamin E by GSH does not appear to contribute significantly to inhibition of peroxidation. During GSH and vitamin E dependent inhibition of lipid peroxidation, vitamin E (reduced form) concentrations remained constant, indicating that GSH maintained vitamin E concentrations. Without GSH, vitamin E concentrations dropped rapidly. By adding vitamin E to microsomes, it was found that inhibition of lipid peroxidation in the presence of GSH occurred at about five‐fold less vitamin E than in the absence of GSH. Inhibition at these lower levels of vitamin E was 85–90% complete. Results indicate that GSH can be used to maintain vitamin E (reduced form) concentrations, thereby lowering the concentration of vitamin E necessary to inhibit microsomal lipid peroxidation.
Preparation and physical properties of some C18 unsaturated fatty esters containingL‐amino acid residues and methyl esters ofN‐stearoylamino acids
Authors: Lie Ken Jie Marcel S. F. , Lao H. B. , Leung David W. Y. 
Published: February 2007

AbstractA series of five C18 unsaturated fatty esters (1–5) containing anL‐amino acid residue (glycine, alanine, valine, leucine, phenylalanine) was prepared from methyl 12‐amino‐9‐cis‐octadecenoate and five methylN‐stearoyl‐amino acid ester derivatives (6–10) from stearoyl chloride and the sameL‐amino acids. The infrared analysis of compounds 1–5 showed characteristic absorption bands at 3300 and 1665 cm−1 for the amino and amido functions, while the amido function in compounds 6–10 gave absorption bands at 3300 and 1680 cm−1. The position of the amido group (peptide linkage) in compounds 1–5 was readily determined by mass spectral analysis.1H nuclear magnetic resonance (NMR) analysis showed a doublet at 7.15 ppm for the amide proton (NHCO) in compounds 1–5, while in compounds 6–10 the amide proton signal appeared at 6.0 ppm. In13C NMR, the amido carbonyl resonance appeared at 171–175 ppm. In compounds 1–5 the effect of the amide function on the ethylene carbon (C‐9) gave a signal at 124.1–125.3 ppm, while the remaining ethylenic carbon appeared at 131.9–132.5 ppm. The methine carbon (C‐12) of the alkenyl chain was shifted to 48.4–49.8 ppm, and the assignment of the various carbon nuclei in the amino acid residue was readily achieved. In the methylN‐stearoylamino acid ester derivatives (6–10), the methine carbon adjacent to the amido system and alpha to the carbomethoxy group appeared between 41.2–57.0 ppm depending on the type of alkyl group present in the amino acid moiety. The phenyl system in compounds 5 and 10 was confirmed by the13C signals in the 127–136 ppm range and by the proton signals in the 7.0–7.27 ppm region.
Effect of dietary α‐linolenate/linoleate balance on crescent type‐anti‐glomerular basement membrane nephritis in rats
Authors: Watanabe Shiro , Suzuki Erika , Kojima Ryoji , Suzuki Yoshio , Okuyama Harumi 
Published: February 2007

AbstractRats were fed diets with three different ratios of α‐linolenate (18∶3 n−3) and linoleate (18∶2 n−6), and then crescentic‐type anti‐glomerular basement membrane (GBM) nephritis was induced. The urinary protein levels and the plasma urea nitrogen levels were significantly higher, and histological abnormalities of glomeruli were seen more frequently in the high‐α‐linolenate group than in the high‐linoleate group. The differences in dietary α‐linolenate/linoleate balances were reflected in the proportions of arachidonate and eicosapentaenoate in glomerular phospholipids. Our results indicate that dietary enrichment with α‐linolenate causes unfavorable effects in this anti‐GBM nephritis model.
Separation of the enantiomers of 1‐alkyl‐2‐acyl‐rac‐glycerol and of 1‐alkyl‐3‐acyl‐rac‐glycerol by high performance liquid chromatography on a chiral column
Authors: Takagi Toru , Okamoto Jiro , Ando Yasuhiro , Itabashi Yutaka 
Published: February 2007

AbstractHigh performance liquid chromatographic separations of two enantiomeric pairs of 1‐alkyl‐2‐acyl‐rac‐glycerol (1‐alkyl‐2‐acyl‐ and 3‐alkyl‐2‐acyl‐sn‐glycerols) and 1‐alkyl‐3‐acyl‐rac‐glycerol (1‐alkyl‐3‐acyl‐ and 3‐alkyl‐1‐acyl‐sn‐glycerols) as 3,5‐dinitrophenylurethanes (3,5‐DNPUs) were carried out on a chiral stationary phase, N‐(R)‐1‐(α‐naphthyl)ethylaminocarbonyl‐(S)‐valine chemically bonded to γ‐aminopropyl silanized silica (Sumipax OA‐4100). Good separation of the enantiomers of 1‐hexadecyl‐2‐hexadecanoyl‐rac‐glycerol was easily achieved within 10 min using hexane/ethylene dichloride/ethanol (80∶20∶1, v/v/v) as a mobile phase. Separation of the enantiomers of 1‐hexadecyl‐3‐hexadecanoyl‐rac‐glycerol was more difficult and required about 80 min to achieve satisfactory peak resolution (0.8) using hexane/ethylene dichloride/ethanol (250∶20∶1, v/v/v) as a mobile phase.
Molecular species composition of phosphatidylcholine fromCrypthecodinium cohnii in relation to growth temperature
Authors: Bell Michael V. , Henderson R. James 
Published: February 2007

AbstractThe molecular species composition was determined for phosphatidylcholine (PC) isolated from the marine dinoflagellateCrypthecodinium cohnii grown at three different temperatures. At all three temperatures the didocosahexaenoyl species comprised about 25% of the PC with 14∶0/22∶6 and 16∶0/22∶6 also being of major importance; these three species comprised 75–82% of the total. Another 20 species were identified, including several short chain disaturated species. Only small differences in the composition of PC were found in response to growth at 16, 23 and 27°C. On dropping the growth temperature from 27°C to 16°C the largest changes were a decrease of 8.9% in saturated/saturated species and an increase of 5.3% in saturated/PUFA species; the 22∶6/22∶6 content only increased slightly (by 1.9% to 25.4%). This unusual molecular species composition is discussed.
Evidence for the unique function of docosahexaenoic acid during the evolution of the modern hominid brain
Authors: Crawford M. A. , Bloom M. , Broadhurst C. L. , Schmidt W. F. , Cunnane S. C. , Galli C. , Gehbremeskel K. , Linseisen F. , Lloyd‐Smith J. , Parkington J. 
Published: February 2007

AbstractThe African savanna ecosystem of the large mammals and primates was associated with a dramatic decline in relative brain capacity associated with little docosahexaenoic acid (DHA), which is required for brain structures and growth. The biochemistry implies that the expansion of the human brain required a plentiful source of preformed DHA. The richest source of DHA is the marine food chain, while the savanna environment offers very little of it. ConsequentlyHomo sapiens could not have evolved on the savannas. Recent fossil evidence indicates that the lacustrine and marine food chain was being extensively exploited at the time cerebral expansion took place and suggests the alternative that the transition from the archaic to modern humans took place at the land/water interface. Contemporary data on tropical lakeshore dwellers reaffirm the above view with nutritional support for the vascular system, the development of which would have been a prerequisite for cerebral expansion. Both arachidonic acid and DHA would have been freely available from such habitats providing the double stimulus of preformed acyl components for the developing blood vessels and brain. The n‐3 docosapentaenoic acid precursor (n‐3 DPA) was the major n‐3‐metabolite in the savanna mammals. Despite this abundance, neither it nor the corresponding n‐6 DPA was used for the photoreceptor nor the synapse. A substantial difference between DHA and other fatty acids is required to explain this high specificity. Studies on fluidity and other mechanical features of cell membranes did not reveal a difference of such magnitude between even α‐linolenic acid and DHA sufficient to explain the exclusive use of DHA. We suggest that the evolution of the large human brain depended on a rich source of DHA from the land/water interface. We review a number of proposals for the possible influence of DHA on physical properties of the brain that are essential for its function.
New developments in phospholipase A2
Authors: Chaminade Brigitte , Le Balle François , Fourcade Olivier , Nauze Michel , Delagebeaudeuf Claire , Gassama‐Diagne Ama , Simon Marie‐Françoise , Fauvel Josette , Chap Hugues 
Published: February 2007

AbstractSome of the most recent data concerning various phospholipases A2, with special emphasis on secretory, cytosolic, and calcium‐independent phospholipases A2 are summarized. Besides their contribution to the production of proinflammatory lipid mediators, the involvement of these enzymes in key cell responses such as apoptosis or tumor cell metastatic potential is also discussed, taking advantage of transgenic models based on gene invalidation by homologous recombination. The possible role of secretory and cytosolic platelet‐activating factor acetyl hydrolases is also briefly mentioned. Finally, the ectopic expression in epididymis of an intestinal phospholipase B opens some novel issues as to the possible function of phospholipases in reproduction.
Changes in membrane microdomains and caveolae constituents in multidrug‐resistant cancer cells
Authors: Lavie Yaakov , Fiucci Giusy , Czarny Malgorzata , Liscovitch Mordechai 
Published: February 2007

AbstractCancer chemotherapy often fails because of the development of tumors which are resistant to most commonly used cytotoxic drugs. This phenomenon, multidrug resistance (MDR), is usually mediated by overexpression of P‐glycoprotein (P‐gp), an ATPase that pumps out the drugs used in chemotherapy, thereby preventing their accumulation in cancer cells and greatly reducing their cytotoxic efficacy. A large body of work indicates that MDR is associated also with marked changes in membrane lipid composition. Most notably, elevated levels of cholesterol, glycosphingolipids (e.g., glucosylceramide), and sphingomyelin have been reported. These lipids are enriched in caveolae and in membrane microdomains termed detergent‐insoluble glycosphingolipid‐enriched complexes (DIGs). Recently we demonstrated that in multidrug‐resistant tumor cells there is a dramatic increase in the number of caveolae and in the level of caveolin‐1, an essential structural constituent of caveolae. Another constituent of membrane microdomains, phospholipase D, is also elevated in MDR cells. These findings may be related to the fact that a significant fraction of cellular P‐gp is associated with caveolin‐rich membrane domains. The possible role of DIGs and caveolae in the acquisition and/or maintenance of the multidrug resistant phenotype is discussed.
Tumor necrosis factor‐α and ceramides in insulin resistance
Authors: Brindley David N. , Wang Chuen‐Neu , Mei Jie , Xu James , Hanna Atef N. 
Published: February 2007

AbstractThe present studies tested the hypothesis that some effects of tumor necrosis factor‐α (TNF‐α) are mediated by activation of sphingomyelinases and the production of ceramides. Differentiated 3T3‐L1 adipocytes were incubated with short‐chain ceramide analogs, (C2‐ and C6‐ceramides:N‐acetyl‐ andN‐hexanoyl‐sphingosines, respectively), and this treatment increased 2‐deoxyglucose uptake in the absence of insulin progressively from 2–24 h. This effect was inhibited by blocking the activations of mitogen‐activated protein kinase, phosphatidylinositol 3‐kinase (PI 3‐kinase), and ribosomal S6 kinase which mediated an increase in GLUT1 concentrations. Long‐term increases in PI 3‐kinase activity associated with insulin receptor substrate‐1 (IRS‐1) increased the proportion of GLUT1 and GLUT4 in plasma membranes. These events explain the increases in noninsulin‐dependent glucose uptake and incorporation of this glucose into the fatty acid and glycerol moieties of triacylglycerol. The mechanisms by which TNF‐α and ceramides increase PI 3‐kinase activity were investigated further by using rat2 fibroblasts. Incubation for 20 min with TNF‐α, bacterial sphingomyelinase, or C2‐ceramides increased PI 3‐kinase activity by about fivefold, and this effect depended upon a stimulation of tyrosine kinase activity and an increase in Ras‐GTP. This demonstrates the existence of a novel signaling pathway for TNF‐α that could contribute to the effects of this cytokine in stimulating basal glucose uptake. By contrast, treating the 3T3‐L1 adipocytes for 2–24 h with C2‐ceramide diminished insulin‐stimulated glucose uptake by decreasing the insulin‐induced translocation of GLUT1 and GLUT4 to plasma membranes. This inhibition was observed when there was no increase in basal glucose uptake, and it occurred downstream of PI 3‐kinase. Our work provides further mechanisms whereby TNF‐α and ceramides produce insulin resistance and decrease the effectiveness of insulin in stimulating glucose disposal from the blood. Conversely, TNF‐α and ceramides increase the ability of adipocytes to take up glucose and store triacylglycerol in the absence of insulin.
Diabetes puts myocardial n‐3 fatty acid status at risk in the absence of supplementation in the rat
Authors: McLennan P. L. , Raederstorff D. 
Published: February 2007

ConclusionsThe changes in fatty acid incorporation into myocardial membranes that occurred with acute diabetes in this study were indicative of depressed PUFA desaturation. However this was largely confined to the long‐chain n‐3 PUFA, DHA. Anti‐arrhythmic efficets of n‐3 PUFA diets were associated with elevated DHA levels. It is conclused that perturbed PUFA metabolism in diabetes puts myocardial n‐3 PUFA status at high risk which may have important implications for heart function and that this may be prevented by low‐level supplementation with purified DHA.
Postprandial hypertriglyceridemia induced by saturated vs. monounsaturated fatty acids is related to reduced hepatic lipoprotein receptors binding in NZW rabbits
Authors: Harbis A. , Juhel C. , Senft M. , Lairon D. 
Published: February 2007

ConclusionsAs compared to a low‐fat control diet, chronic ingestion of a SFA diet increased postprandial lipemia, did not noticeably modify lipoprotein lipase and hepatic lipase activities, and decreased binding activities to LDL‐R as well as LSR. On the contrary, a MUFA‐rich diet did not alter postprandial lipemia, had no effect on lipase activities, but increased binding activities to LDL‐R and to LSR measured on hepatocyte plasmic membrane. In both cases, postprandial triglyceridemia and accumulation of triglycerides from dietary origin were inversely correlated to LDL‐R and LSR binding activities.The reduced LDL‐R as well as LSR binding activities could explain the postprandial hypertriglyceridemia observed in rabbits chronically ingesting SFA. MUFA could prevent postprandial accumulation of TRL by accelerating their hepatic uptake mediated by LDL‐R and LSR.
Effects of age and dietary n‐3 fatty acids on the metabolism of [13C]‐α‐linolenic acid
Authors: Vermunt S. H. F. , Mensink R. P. , Simonis A. M. G. , Hornstra G. 
Published: February 2007

ConclusionWe conclude that13C α‐linolenic acid is converted into its LCP. The conversion of α‐linolenic acid into its LCP appears to be inhibited on diets rich in EPA/DHA, while it appears not to be influenced by age. In addition, oxidation of α‐linolenic acid is not dependent on age or dietary α‐linolenic acid, but may be slightly increased on diets rich in EPA/DHA.
A chronic ethanol‐feeding study in rhesus monkeys
Authors: Pawlosky Robert J. , Salem Norman 
Published: February 2007

AbstractThis study describes the effect of chronic ethanol‐feeding in rhesus monkeys. Animals which were maintained on a diet containing 18:2n‐6 and 18:3n‐3 as 1.4 and 0.08% of the calories, respectively, and consumed alcohol (mean 2.6 g kg−1 d−1) had decreased amounts of 20:4n‐6 and 22:6n‐3 in their livers and plasma lipids compared with controls. Alcohol consumption did not appear to effect the absorption of2H5‐18:2n‐6 and 18:3n‐3 esters into the blood following an oral dose. There was an increase in2H5 enrichment in plasma 20:4n‐6 and 22:6n‐3, indicating that alcohol may have increased production of these fatty acids. There was a greater concentration of 4‐hydroxynonenal in the plasma of alcohol‐exposed monkeys compared to controls.