Home About us Contact
|
Home About us Contact | ||
|
|
||
SO
Selected AbstractsMixed crystal of bis(,2 -N,N-di-n-butyldithiocarbamato-S,S,S,)-bis(N,N-di-n-butyldithiocarbamato-S,S,)-di-zinc(II) and bis(,2 -N,N-di-n-butyldithiopercarbamato-S,O,O,)-bis(N,N-di-n-butyldithiocarbamato-S,S,)-di-zinc(II)CRYSTAL RESEARCH AND TECHNOLOGY, Issue 10 2007F. Emmerling Abstract The title compounds Zn2[S2CN(n-C4H9)2]41 and Zn2[(S(SO)CN(n-C4H9)2)(S2CN(n-C4H9)2)]23 build mixed crystals in the ratio 0.42: 0.58. Each compound forms dimers, in which the monomer moieties are related via a two-fold axis, coinciding with that of the monoclinic space group C2/c. The lattice parameters are a = 23.581(9), b = 17.112(5), c = 16.372(9) Å, and , = 128.33(3)°. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Fly Six-type homeodomain proteins Sine oculis and Optix partner with different cofactors during eye developmentDEVELOPMENTAL DYNAMICS, Issue 3 2005Kristy L. Kenyon Abstract Two members from the Six class of homeobox transcription factors, Sine oculis (SO) and Optix, function during development of the fly visual system. Differences in gain-of-function phenotypes and gene expression suggest that these related factors play distinct roles in the formation of the fly eye. However, the molecular nature of their functional differences remains unclear. In this study, we report the identification of two novel factors that participate in specific partnerships with Sine oculis and Optix during photoreceptor neurons formation and in eye progenitor cells. This work shows that different cofactors likely mediate unique functions of Sine oculis and Optix during the development of the fly eye and that the repeated requirement for SO function at multiple stages of eye development reflects the activity of different SO,cofactor complexes. Developmental Dynamics 234:497,504, 2005. © 2005 Wiley-Liss, Inc. [source] Electrochemical Preparation of Poly(acriflavine) Film-Modified Electrode and Its Electrolcatalytic Properties Towards NADH, Nitrite and Sulfur OxoanionsELECTROANALYSIS, Issue 9 2007Shen-Ming Chen Abstract Electrochemical polymerization of acriflavine (AF) was carried out onto glassy carbon electrodes (GCE) from the aqueous buffer solution containing 1.5×10,3,M AF monomer (pH,3.5) which produced a thin electrochemically active film. This is noted as poly(AF) film modified electrodes (PAF/GCE). This modified electrode was shown a stable reversible redox couple centered at +0.22,V in pH,3.5 buffer solutions. PAF/GCE was found to be more stable in acidic solutions and its formal potential was found to be pH dependent with a slope close to ,60,mV/pH. The electrochemical deposition kinetics of poly(AF) onto gold coated quartz crystal was studied by using electrochemical quartz crystal microbalance (EQCM) combined with cyclic voltammetry (CV). PAF/GCE was found be good mediator for electrochemical oxidation of reduced nicotinamide adenine dinucleotide (NADH) in pH,5 buffer solutions. The electrocatalytic oxidation of SO and electrocatalytic reduction of NO, SO and S2O were carried out at PAF/GCE electrode in acidic aqueous solutions. The electrocatalytic oxidation of NADH was also investigated by using amperometric method. [source] Observed and predicted reproduction of Ceriodaphnia dubia exposed to chloride, sulfate, and bicarbonate,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2010Peter J. Lasier Abstract Chronic toxicities of Cl,, SO, and HCO to Ceriodaphnia dubia were evaluated in low- and moderate-hardness waters using a three-brood reproduction test method. Toxicity tests of anion mixtures were used to determine interaction effects and to produce models predicting C. dubia reproduction. Effluents diluted with low- and moderate-hardness waters were tested with animals acclimated to low- and moderate-hardness conditions to evaluate the models and to assess the effects of hardness and acclimation. Sulfate was significantly less toxic than Cl, and HCO in both types of water. Chloride and HCO toxicities were similar in low-hardness water, but HCO was the most toxic in moderate-hardness water. Low acute-to-chronic ratios indicate that toxicities of these anions will decrease quickly with dilution. Hardness significantly reduced Cl, and SO toxicity but had little effect on HCO. Chloride toxicity decreased with an increase in Na+ concentration, and HCO toxicity may have been reduced by the dissolved organic carbon in effluent. Multivariate models using measured anion concentrations in effluents with low to moderate hardness levels provided fairly accurate predictions of reproduction. Determinations of toxicity for several effluents differed significantly depending on the hardness of the dilution water and the hardness of the water used to culture test animals. These results can be used to predict the contribution of elevated anion concentrations to the chronic toxicity of effluents; to identify effluents that are toxic due to contaminants other than Cl,, SO, and HCO; and to provide a basis for chemical substitutions in manufacturing processes. Environ. Toxicol. Chem. 2010;29:347,358. Published 2009 SETAC [source] Cyclic fatty acids in sunflower oils during frying of frozen foods with oil replenishment,EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 2 2007Antonio Romero Abstract Frying of frozen foods has become popular because it considerably reduces cooking time. Polymers and cyclic fatty acid monomers (CFAM) formed during frying are potentially toxic and therefore their production should be minimized. Twenty discontinuous fryings of different frozen foods were carried out over ten consecutive days, in sunflower oil (SO) and in high-oleic acid sunflower oil (HOSO), by adding fresh oil after each frying to bring the volume of the fryer oil back to 3,L. CFAM methyl ester derivates were hydrogenated, isolated, concentrated and quantified by HPLC using a reverse-phase column, followed by gas chromatography. After 20,fryings, significantly higher contents of polar material, polymers and CFAM (all p,<0.001) were found in SO than in HOSO. Bicyclic compound formation was four times higher in SO (p,<0.001). The fat from the fried potatoes presented a polymer content very similar to that of their corresponding oils. The 100-g rations of the SO-fried potatoes from the 20th frying supply 49 or 15%, respectively, more polymers and CFAM and 1,mg more bicyclic fatty acids than the 100-g rations of HOSO-fried potatoes. Because digestion and absorption of polar material, polymers and CFAM occur, the data clearly show the advantageousness and advisability of frying with HOSO rather than SO. [source] An Expedient Synthesis of Perfluorinated Tetraazamacrocycles: New Ligands for Copper-Catalyzed Oxidation under Fluorous Biphasic ConditionsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 20 2006Augustin de Castries Abstract Conjugate additions of cyclam to perfluorohexyl vinyl sulfone and sulfoxide, which act as efficient fluorous Michael acceptors, readily give access to new fluoro-ponytail tetraazamacrocycles in good yields. The solubility of the N -tetrasubstituted macrocycles depends dramatically on the nature of the polar function (SO or SO2): the sulfoxide cyclam derivative is soluble in perfluorodecaline (pfd) and perfluoromethylcyclohexane (pfmc) while the sulfonyl derivative is almost insoluble in organic or fluorous solvents. In agreement with the well known affinity of cyclam for copper(II) ions, stable copper complexes of the fluorous macrocyclic ligands have been isolated and characterized. In chloroform/methanol, complexes with four perfluorinated tails have been obtained from reaction of the tetra- N -perfluorohexylsulfinyl-substituted macrocycle with copper nitrate and copper perfluorocarboxylate. In trifluoroethanol, a selective retro-Michael reaction has been observed and the same reaction specifically gives copper complexes of the tri- N -substituted macrocycle. Complexes with three and four fluorous tails associated with perfluorocarboxylate counteranions are soluble in fluorous solvents (pfd and pfmc). These copper complexes were tested as catalysts for the oxidation of cyclohexene by molecular oxygen in the presence of tert -butyl hydroperoxide (tbhp). The oxidation reactions proceed under fluorous biphasic conditions and the catalyst can be recovered and reused. Quenching experiments indicate that cyclohexenyl hydroperoxide is the main oxidation product of the reaction performed with or without tbhp. Interestingly, these perfluorinated copper complexes are good, recyclable catalysts for the oxidation of cyclohexene by molecular oxygen without tbhp at room temperature and 65 °C.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Compactifications of the heterotic string with unitary bundlesFORTSCHRITTE DER PHYSIK/PROGRESS OF PHYSICS, Issue 11 2006T. Weigand Abstract We describe a large new class of four-dimensional supersymmetric string vacua defined as compactifications of the E8 × E8 and the SO(32) heterotic string on smooth Calabi-Yau threefolds with unitary gauge bundles and heterotic five-branes. The conventional gauge symmetry breaking via Wilson lines is replaced by the embedding of non-flat line bundles into the ten-dimensional gauge group, thus opening up the way for phenomenologically interesting string compactifications on simply connected manifolds. After a detailed analysis of the four-dimensional effective theory we exemplify the general framework by means of a couple of explicit examples involving the spectral cover construction of stable holomorphic bundles. As for the SO(32) heterotic string, the resulting vacua can be viewed, in the S-dual Type I picture, as a generalisation of magnetized D9/D5-brane models. In the case of the E8 × E8 string, we find a natural way to construct realistic MSSM-like models, either directly or via a flipped SU(5) GUT scenario. [source] Compactifications on half-flat manifolds,FORTSCHRITTE DER PHYSIK/PROGRESS OF PHYSICS, Issue 3 2005S. Gurrieri Abstract We review various aspects of compactifications of heterotic and type II supergravities on six dimensional manifolds. In the general framework of non-Kähler compactifications, emphasis is made on a particular class of manifolds with SU(3)-structure named half-flat. We recall how these manifolds appeared in the context of mirror symmetry of type II theories, providing mirror configurations to Calabi-Yau compactifications with NS-NS electric fluxes. In the heterotic sector, they generate a potential for all moduli, and are expected to break the E8 × E8 gauge group down to SO(10) × E8 in 4 dimensions. [source] M-theory and gauged supergravities,FORTSCHRITTE DER PHYSIK/PROGRESS OF PHYSICS, Issue 2 2005D. Roest Abstract We present a pedagogical discussion of the emergence of gauged supergravities from M-theory. First, a review of maximal supergravity and its global symmetries and supersymmetric solutions is given. Next, different procedures of dimensional reduction are explained: reductions over a torus, a group manifold and a coset manifold and reductions with a twist. Emphasis is placed on the consistency of the truncations, the resulting gaugings and the possibility to generate field equations without an action. Using these techniques, we construct a number of gauged maximal supergravities in diverse dimensions with a string or M-theory origin. One class consists of the CSO gaugings, which comprise the analytic continuations and group contractions of SO(n) gaugings. We construct the corresponding half-supersymmetric domain walls and discuss their uplift to D- and M-brane distributions. Furthermore, a number of gauged maximal supergravities are constructed that do not have an action. [source] Distribution of benthic diatoms in U.S. rivers in relation to conductivity and ionic compositionFRESHWATER BIOLOGY, Issue 8 2003Marina Potapova Summary 1We quantified the relationships between diatom relative abundance and water conductivity and ionic composition, using a dataset of 3239 benthic diatom samples collected from 1109 river sites throughout the U.S.A. [U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program dataset]. This dataset provided a unique opportunity to explore the autecology of freshwater diatoms over a broad range of environmental conditions. 2Conductivity ranged from 10 to 14 500 ,S cm,1, but most of the rivers had moderate conductivity (interquartile range 180,618 ,S cm,1). Calcium and bicarbonate were the dominant ions. Ionic composition, however, varied greatly because of the influence of natural and anthropogenic factors. 3Canonical correspondence analysis (CCA) and Monte Carlo permutation tests showed that conductivity and abundances of major ions (HCO + CO, Cl,, SO, Ca2+, Mg2+, Na+, K+) all explained a statistically significant amount of the variation in assemblage composition of benthic diatoms. Concentrations of HCO + CO and Ca2+ were the most significant sources of environmental variance. 4The CCA showed that the gradient of ionic composition explaining most variation in diatom assemblage structure ranged from waters dominated by Ca2+ and HCO + CO to waters with higher proportions of Na+, K+, and Cl,. The CCA also revealed that the distributions of some diatoms correlated strongly with proportions of individual cations and anions, and with the ratio of monovalent to divalent cations. 5We present species indicator values (optima) for conductivity, major ions and proportions of those ions. We also identify diatom taxa characteristic of specific major-ion chemistries. These species optima may be useful in future interpretations of diatom ecology and as indicator values in water-quality assessment. [source] Effects of melatonin and caffeic acid phenethyl ester on testicular injury induced by myocardial ischemia/reperfusion in ratsFUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 3 2005Mukaddes E Abstract Experimental studies indicate that ischemia/reperfusion (I/R) causes remote organ injury although the molecular mechanism has not been clearly defined. In this report, the role of oxidative injury on testicular damage following myocardial I/R injury and the effects of antioxidant agents, melatonin and caffeic acid phenethyl ester (CAPE), on testicular injury were investigated. As far as we know, this is the first report demonstrating that myocardial I/R induces damage to the testes. Thirty-two male Wistar rats were randomly divided into four groups: sham operation (SO), I/R + vehicle, I/R + melatonin, and I/R + caffeic acid phenethyl ester. To produce cardiac damage, the left main coronary artery was occluded for 30 min, followed by 120 min reperfusion, in anesthetized rats. Serum nitric oxide (NO) and malondialdehyde (MDA) levels and morphological changes were examined. I/R was accompanied by a significant increase in serum MDA and NO levels, whereas, melatonin and CAPE administration significantly reduced these values. Melatonin was more efficient in reducing MDA levels than CAPE (P < 0.05). I/R induced myocardial damage, manifested as the histopathological evidence of intracellular vacuolization, interstitial edema, neutrophil infiltration and coagulative necrosis. I/R + vehicle group showed many histological alterations such as focal tubular atrophy, and degeneration and disorganization of the seminiferous epithelium in testes. The number of atrophic tubules and degenerating cells was significantly higher in I/R + vehicle group than that of SO group. Melatonin and CAPE significantly reduced the number of degenerating cells; additionally, melatonin reduced the number of atrophic tubules (P < 0.05). Our results indicate that myocardial I/R induces severe testicular damage and antioxidant agents, especially melatonin, have protective effects on testicular injury after myocardial I/R. Our data emphasize that oxygen-based reactants may play a central role in remote organ injury. [source] Distribution of Chemical Constituents in Superimposed Ice from Austre Brøggerbreen, SpitsbergenGEOGRAFISKA ANNALER SERIES A: PHYSICAL GEOGRAPHY, Issue 1 2000H. Motoyama 10 m and 2.3 m ice cores were obtained on Austre Brøggerbreen, Spitsbergen in Svalbard (78°53,N, 11°56,E, 450 m a.s.l.) in September 1994 and in March 1995, respectively. Stratigraphy, bulk density, pH, electrical conductivity, and major ions were obtained from the core samples. The chemical effect of meltwater percolation through snow/ice is examined. Good correlation between Cl, and Na+ was obtained. The ratio of Cl, to Na+ was 1.14 which was nearly the same value as in bulk sea water. However, the variation of Cl,/Na+ shows that higher ratio occured in the bubble-free ice. Furthermore the Cl, ions remain in higher concentration than SO 4 2, or Na+ ions. [source] Computational NMR Spectroscopy of Transition-Metal/Nitroimidazole Complexes: Theoretical Investigation of Potential RadiosensitizersHELVETICA CHIMICA ACTA, Issue 10 2005Teodorico The computed chemical shifts of transition-metal complexes with dimetridazole (=,1,2-dimethyl-5-nitro-1H -imidazole; 1), a prototypical nitro-imidazole-based radiosensitizer, are reported at the GIAO-BP86 and -B3LYP levels for BP86/ECP1-optimized geometries. These complexes comprise [MCl2(1)2] (M,=,Zn, Pd, Pt), [RuCl2(DMSO)2(1)2], and [Rh2(O2CMe)4(1)2]. Available ,(1H) and ,(15N) values, and ,,(1H) and ,,(15N) coordination shifts are well-reproduced theoretically, provided solvation and relativistic effects are taken into account by means of a polarizable continuum model and suitable methods including spin,orbit (SO) coupling, respectively. These effects are particularly important for the metal-coordinated N-atom, where the contributions from solvation and relativity can affect ,(15N) and ,,(15N) values up to 10,20,ppm. The 195Pt chemical shifts of cis - and trans -[PtCl2(1)2] are well-reproduced using the zero-order regular approximation including SO coupling (ZORA-SO). Predictions are reported for 99Ru and 103Rh chemical shifts, which suggest that these metal centers could be used as additional, sensitive NMR probes in their complexes with nitro-imidazoles. [source] Electrical activation of common bile duct nerves modulates sphincter of Oddi motility in the Australian possumHPB, Issue 4 2005Y. Sonoda Abstract Background: Sphincter of Oddi (SO) motility is regulated by extrinsic and intrinsic nerves. The existence of neural circuits between the SO and the proximal extrahepatic biliary tree has been reported, but they are poorly understood. Using electrical field stimulation (EFS), we determined if a neural circuit exists between the common bile duct (CBD) and the SO in anaesthetized Australian brush-tailed possums. Methods: The gallbladder, cystic duct or CBD were subjected to EFS with a stimulating electrode. Spontaneous SO phasic waves were measured by manometry. Results: EFS at sites on the distal CBD (12,20 mm proximal to the SO), but less commonly at more proximal CBD, evoked a variety of responses consisting of an excitatory and/or inhibitory phase. Bi-phasic responses consisting of an excitation followed by inhibition were the most common. Tri-phasic responses were also observed as well as excitation or inhibition only. These evoked responses were blocked by topical application of local anaesthetic to the distal CBD or transection of the CBD. EFS at sites on the gallbladder body, neck or cystic duct did not consistently evoke an SO response. Pretreatment with atropine or guanethidine reduced the magnitude of the evoked response by about 50% (p<0.05), pretreatment with hexamethonium had no consistent effect and pretreatment with a nitric oxide synthase inhibitor increased the response. Discussion: A neural circuit(s) between the SO and the distal CBD modulates SO motility. Damage to this area of the CBD during bile duct exploration surgery could adversely affect SO motility. [source] Relationship of topography to surface water chemistry with particular focus on nitrogen and organic carbon solutes within a forested watershed in Hokkaido, JapanHYDROLOGICAL PROCESSES, Issue 2 2006Akiko Ogawa Abstract We studied the relationships between streamwater chemistry and the topography of subcatchments in the Dorokawa watershed in Hokkaido Island, northern Japan, to examine the use of topography as a predictor of streamwater chemistry in a watershed with relatively moderate terrain compared with other regions of Japan. Topographic characteristics of the Dorokawa watershed and its subcatchments were expressed as topographic index (TI) values, which ranged from 4·5 to 20·4 for individual grid cells (50 × 50 m2), but averaged from 6·4 to 7·4 for the 20 subcatchments. Streamwater samples for chemical analyses were collected four times between June and October 2002 from 20 locations in the watershed. The pH of water that passed through the watershed increased from ,5·0 to 7·0, with major increases in Na+ and Ca2+ and marked decreases in NO3, and SO. Distinctive spatial patterns were observed for dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and NO3, concentrations of streamwater across the watershed. Statistical analyses indicated significant linear relationships between the average TI values of subcatchments and DOC, DON, and NO3, concentrations. Furthermore, the proportion of DOC in streamwaters in the wet season increased with TI values relative to other nitrogen species, whereas NO3, concentrations decreased with TI. The gradients of soil wetness and the presence of wetlands explained many of the observed spatial and temporal patterns of DOC, DON, and NO3, concentrations in the surface waters of the Dorokawa watershed. Our results suggest that the TI is especially useful for predicting the spatial distribution of DOC, DON and NO3, in the surface waters of Hokkaido, where topographical relief is moderate and wetlands more common than in other regions of Japan. Copyright © 2006 John Wiley & Sons, Ltd. [source] The influences of the Southern and North Atlantic Oscillations on climatic surface variables in TurkeyHYDROLOGICAL PROCESSES, Issue 6 2005M. Ça, atay Karabörk Abstract In this study, Turkish climatic variables (precipitation, stream flow and maximum and minimum temperatures) were first analysed in association with both the Southern Oscillation (SO) and the North Atlantic Oscillation (NAO). The relationships between Turkish maximum and minimum monthly temperatures and the extreme phases of the SO (El Niño and La Niña events) were examined. The results of this analysis showed that relationships between Turkish monthly maximum temperatures and El Niño and La Niña contain some complexity still to be identified, because both events produce a signal indicating a correspondence with cold anomalies in the aggregate composites. A relationship between turkish minimum temperatures and El Niño was detected in western Anatolia, whereas there was no significant and consistent signal associated with La Niña. Moreover a series of cross-correlation analyses was carried out to demonstrate the teleconnections between the climatic variables and both the NAO and SO. The NAO during winter was found to influence precipitation and stream-flow patterns. In contrast temperature patterns appeared to be less sensitive to the NAO. Furthermore, lag-correlation results indicated a prediction potential for both precipitation and stream-flow variables in connection with the NAO. Simultaneous and time-lag correlations between the climatic variables and the SO index, in general, indicated weaker relationships in comparison with those for the NAO. These analyses also showed that the influences of the SO on Turkish temperature data are negligible. The outcomes were presented in conjunction with an explanation regarding physical mechanisms behind the implied teleconnections. Copyright © 2004 John Wiley & Sons, Ltd. [source] Geochemical weathering at the bed of Haut Glacier d'Arolla, Switzerland,a new modelHYDROLOGICAL PROCESSES, Issue 5 2002M. Tranter Waters were sampled from 17 boreholes at Haut Glacier d'Arolla during the 1993 and 1994 ablation seasons. Three types of concentrated subglacial water were identified, based on the relative proportions of Ca2+, HCO3, and SO42, to Si. Type A waters are the most solute rich and have the lowest relative proportion of Si. They are believed to form in hydrologically inefficient areas of a distributed drainage system. Most solute is obtained from coupled sulphide oxidation and carbonate dissolution (SO,CD). It is possible that there is a subglacial source of O2, perhaps from gas bubbles released during regelation, because the high SO42, levels found (up to 1200 µeq/L) are greater than could be achieved if sulphides are oxidized by oxygen in saturated water at 0 °C (c.414 µeq/L). A more likely alternative is that sulphide is oxidized by Fe3+ in anoxic environments. If this is the case, exchange reactions involving FeIII and FeII from silicates are possible. These have the potential to generate relatively high concentrations of HCO3, with respect to SO42,. Formation of secondary weathering products, such as clays, may explain the low Si concentrations of Type A waters. Type B waters were the most frequently sampled subglacial water. They are believed to be representative of waters flowing in more efficient parts of a distributed drainage system. Residence time and reaction kinetics help determine the solute composition of these waters. The initial water,rock reactions are carbonate and silicate hydrolysis, and there is exchange of divalent cations from solution for monovalent cations held on surface exchange sites. Hydrolysis is followed by SO,CD. The SO42, concentrations usually are <414 µeq/L, although some range up to 580 µeq/L, which suggests that elements of the distributed drainage system may become anoxic. Type C waters were the most dilute, yet they were very turbid. Their chemical composition is characterized by low SO42, : HCO3, ratios and high pH. Type C waters were usually artefacts of the borehole chemical weathering environment. True Type C waters are believed to flow through sulphide-poor basal debris, particularly in the channel marginal zone. The composition of bulk runoff was most similar to diluted Type B waters at high discharge, and was similar to a mixture of Type B and C waters at lower discharge. These observations suggest that some supraglacial meltwaters input to the bed are stored temporarily in the channel marginal zone during rising discharge and are released during declining flow. Little of the subglacial chemical weathering we infer is associated with the sequestration of atmospheric CO2. The progression of reactions is from carbonate and silicate hydrolysis, through sulphide oxidation by first oxygen and then FeIII, which drives further carbonate and silicate weathering. A crude estimate of the ratio of carbonate to silicate weathering following hydrolysis is 4 : 1. We speculate that microbial oxidation of organic carbon also may occur. Both sulphide oxidation and microbial oxidation of organic carbon are likely to drive the bed towards suboxic conditions. Hence, we believe that subglacial chemical weathering does not sequester significant quantities of atmospheric CO2 and that one of the key controls on the rate and magnitude of solute acquisition is microbial activity, which catalyses the reduction of FeIII and the oxidation of FeS2. Copyright © 2002 John Wiley & Sons, Ltd. [source] Kinetic evidence for the copper peroxide intermediate with two copper ions in proximityINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 7 2006S. Selvarani The decomposition of caroate (peroxomonosulfate, PMS) is catalyzed by Cu(II) ions even at 5 × 10,5 M in aqueous alkaline solution. The rate is second order in copper(II) ions concentrations and first order in [PMS]. The rate constant values are found to decrease with increase in hydroxide ion concentrations. The turnover number for the reaction is estimated as >1000. The experimental results suggest that the formation of peroxide type intermediate with two copper(II) ions is the rate-determining step. This peroxide intermediate reacts with another molecule of PMS to give the products oxygen, SO and copper ions. The overall entropy of activation is positive with a value of ,20 cals/mol/K. The very high turnover number suggests that Cu(II) ion is one of the best catalysts for the decomposition of caroate ions in alkaline medium. The reaction also represents a system in which metal ion catalyzed decomposition of caroate does not involve radical intermediates. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 439,443, 2006 [source] Relative energies of conformations and sulfinyl oxygen-induced pentacoordination at silicon in 4-bromo- and 4,4-dibromo-4-silathiacyclohexane 1-oxide: A computational studyINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 4 2005Fillmore Freeman Abstract The equilibrium geometries and relative energies of the chair, twist, and boat conformations of cis - and trans -4-bromo-4-silathiacyclohexane 1-oxide and 4,4-dibromo-4-silathiacyclohexane 1-oxide have been calculated at the B3LYP/6-311G(d,p) and MP2/6-311+G(d,p) theoretical levels. The axial (SO) chair conformers of the sulfoxides are of lower energy than the chair conformers of the corresponding equatorial (SO) sulfoxides. The chair conformer of the axial (SO) trans -4-bromo-4-silathiacyclohexane 1-oxide is only 0.10 kcal/mol more stable than the corresponding 1,4-boat conformer which is stabilized by a transannular coordination of the sulfinyl oxygen with silicon that results in trigonal bipyramidal geometry at silicon. The 1,4-boat structure of equatorial (SO) trans -4-bromo-4-silathiacyclohexane 1-oxide is a transition state and is 5.77 kcal/mol higher in energy than the respective chair conformer. The 1,4-boat conformer of axial (SO) 4,4-dibromo-4-silathiacyclohexane 1-oxide is also stabilized by transannular coordination of the sulfinyl oxygen and silicon, but it is 4.31 kcal/mol higher in energy than the corresponding chair conformer. The relatively lower stability of the 1,4-boat conformer of 4,4-dibromo-4-silathiacyclohexane 1-oxide may be due to repulsive interactions of the axial halogen and sulfinyl oxygen atom. The relative energies of the conformers and transition states are discussed in terms of hyperconjugative interactions, orbital interactions, nonbonded interactions, and transannular sulfinyl oxygen-silicon coordination. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005 [source] Self-Objectification and Exercise Behaviors: The Mediating Role of Social Physique AnxietyJOURNAL OF APPLIED BIOBEHAVIORAL RESEARCH, Issue 3-4 2007Lise Melbye Self-objectification (SO) and Social Physique Anxiety (SPA) were investigated in relation to reported exercise behaviors (EBs). A conceptual model was used in which SPA was posited as a mediating variable between SO and EBs categorized as protective or permissive. Two hundred and ninety-one women (age range = 18,74 years) completed the SO, SPA, and EB questionnaires. Women lower in SO reported exercising more, wearing more concealing exercise apparel, and preferring outdoors locations. The models were found to fit the data adequately, but only the path from SO to SPA was significant. These results reaffirm the relationship between SO and SPA, but further understanding of the potential effects of SO on behaviors involving health, body, and exercise is required. [source] Chronic toxicity/oncogenicity study of styrene in cd-1 mice by inhalation exposure for 104 weeksJOURNAL OF APPLIED TOXICOLOGY, Issue 3 2001George Cruzan Abstract Groups of 70 male and 70 female Charles River CD-1 mice were exposed whole body to styrene vapor at 0, 20, 40, 80 or 160 ppm 6 h per day 5 days per week for 98 weeks (females) or 104 weeks (males). The mice were observed daily; body weights, food and water consumption were measured periodically, a battery of hematological and clinical pathology examinations were conducted at weeks 13, 26, 52, 78 and 98 (females)/104 (males). Ten mice of each gender per group were pre-selected for necropsy after 52 and 78 weeks of exposure and the survivors of the remaining 50 of each gender per group were necropsied after 98 or 104 weeks. An extensive set of organs from the control and high-exposure mice were examined histopathologically, whereas target organs, gross lesions and all masses were examined in all other groups. Styrene had no effect on survival in males. Two high-dose females died (acute liver toxicity) during the first 2 weeks; the remaining exposed females had a slightly higher survival than control mice. Levels of styrene and styrene oxide (SO) in the blood at the end of a 6 h exposure during week 74 were proportional to exposure concentration, except that at 20 ppm the SO level was below the limit of detection. There were no changes of toxicological significance in hematology, clinical chemistry, urinalysis or organ weights. Mice exposed to 80 or 160 ppm gained slightly less weight than the controls. Styrene-related non-neoplastic histopathological changes were found only in the nasal passages and lungs. In the nasal passages of males and females at all exposure concentrations, the changes included respiratory metaplasia of the olfactory epithelium with changes in the underlying Bowman's gland; the severity increased with styrene concentration and duration of exposure. Loss of olfactory nerve fibers was seen in mice exposed to 40, 80 or 160 ppm. In the lungs, there was decreased eosinophilia of Clara cells in the terminal bronchioles and bronchiolar epithelial hyperplasia extending into alveolar ducts. Increased tumor incidence occurred only in the lung. The incidence of bronchioloalveolar adenomas was significantly increased in males exposed to 40, 80 or 160 ppm and in females exposed to 20, 40 and 160 ppm. The increase was seen only after 24 months. In females exposed to 160 ppm, the incidence of bronchiolo-alveolar carcinomas after 24 months was significantly greater than in the controls. No difference in lung tumors between control and styrene-exposed mice was seen in the intensity or degree of immunostaining, the location of tumors relative to bronchioles or histological type (papillary, solid or mixed). It appears that styrene induces an increase in the number of lung tumors seen spontaneously in CD-1 mice. Copyright © 2001 John Wiley & Sons, Ltd. [source] Calculations of frequency-dependent molecular magnetizabilities with quasi-relativistic time-dependent generalized unrestricted Hartree,Fock methodJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 4 2007Terutaka Yoshizawa Abstract The time-dependent generalized unrestricted Hartree,Fock (TDGUHF) method combined with a two-component quasi-relativistic Hamiltonian generated from the Douglas,Kroll,Hess (DKH) transformation was developed to calculate frequency-dependent molecular magnetizabilities, which are the linear response quantity of a molecule to an external magnetic field. By calculating the magnetizabilities of H2X (X = O, S, Se, and Te), the noble gases (He, Ne, Ar, Kr, and Xe) and small open shell molecules (CH2, CH3, and O2), we found that scalar relativistic terms affect mainly the diamagnetic magnetizability and spin-orbit (SO) interaction affects the paramagnetic magnetizability. © 2007 Wiley Periodicals, Inc. J Comput Chem 28: 740,747, 2007 [source] Inclusion of Blended Lipid Solutions as Functional Ingredients to Alter the Fatty Acid Profile of Beef PattiesJOURNAL OF FOOD SCIENCE, Issue 7 2010A.C. Lowder Abstract:, Beef patties formulated to contain beef fat, plant oil, and a rosemary extract to increase unsaturated fatty acid content and maintain desirable sensory attributes were compared to control beef patties formulated without plant oils. Treatment patties were formulated to a fat content of 10% or 20% by combining beef trimmings (6% fat) with 4% or 14% addition of a lipid blend. Blends contained 57% beef tallow, 0.3% rosemary extract, and 43% of high oleic safflower oil (SO), olive oil (OO), or corn oil (CO). Lipid oxidation, as measured by TBA values, of treatment patties were similar to control patties after 0 and 3 d of refrigerated (2 °C) storage and up to 56 d of frozen (,10 °C) storage. Cooked lipid blend patties having a fat content of 10% or 20% were similar to or higher than control patties for juiciness and were no different for other sensory attributes evaluated. At fat levels of 10% or 20%, oleic acid (18: 1) in cooked SO patties (46.1% and 50.3%, respectively) and OO patties (43.8% and 48.1%, respectively) was higher than the control (37.3% and 37.6%, respectively). Unsaturated to saturated fatty acid ratios at the 10% or 20% fat levels were higher in SO (1.37 and 1.60, respectively) and CO (1.40 and 1.48, respectively) patties than the control (0.97 and 0.94, respectively). Beef patties manufactured with varying lipid blends increased unsaturated fatty acid content and were similar in physical characteristics and sensory attributes of all beef patties formulated without lipid blends. Practical Application:, The development of healthier beef products that will be more appealing to consumers has long been an industry goal. The authors believe that lipid blends such as the one used in this study could be used to create such products, not only in the form of beef patties, but any number of processed meat products. Because the materials and equipment used to create the lipid blends in this study are widely available, their incorporation into meat products would represent a small capital investment. This is an important factor in bringing a reasonably priced, healthier product to consumers. [source] Increased heat-shock protein 90 expression contributes to impaired adaptive cytoprotection in the gastric mucosa of portal hypertensive ratsJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 6 2009Masayuki Tominaga Abstract Background and Aims:, Portal hypertensive (PHT) gastropathy results in an increased susceptibility to damage. Adaptive cytoprotection against ethanol-induced damage is impaired in the gastric mucosa of rats with portal hypertension. Excessive nitric oxide (NO) production occurs in portal hypertension and is mediated in part via heat-shock protein (Hsp)90 production. The aim of this study was to investigate the relation between adaptive cytoprotection after exposure to ethanol and gastric expression of Hsp90 in PHT rats. Methods:, Portal hypertension was induced in rats by staged portal vein occlusion. Adaptive cytoprotection to 70% ethanol was evaluated by assessing the injury index of the gastric mucosa with or without pretreatment with 10% ethanol. Expression of Hsp90 mRNA was evaluated by real-time polymerase chain reaction, and expression of Hsp90 protein was evaluated by western blotting. The effect of Hsp90 inhibition in PHT rats was evaluated by administration of geldanamycin. Results:, Gastric Hsp90 mRNA expression in PHT rats was significantly less than that in sham-operated (SO) controls. However, after 10% ethanol pretreatment, Hsp90 mRNA expression was significantly greater in PHT rats than in SO controls. In PHT rats, gastric Hsp90 protein expression after 10% ethanol pretreatment was significantly greater than that without the pretreatment. However, the pretreatment had no effect on the injury index compared to SO rats. Administration of geldanamycin prior to 10% ethanol pretreatment significantly decreased the injury index in response to 70% ethanol in the PHT rats. Conclusions:, These results show that 10% ethanol pretreatment markedly increases gastric Hsp90 expression in PHT rats. Excessive production of Hsp90 may contribute impaired adaptive cytoprotection. [source] Comparative innervation of cephalic photophores of the loosejaw dragonfishes (Teleostei: Stomiiformes: Stomiidae): Evidence for parallel evolution of long-wave bioluminescenceJOURNAL OF MORPHOLOGY, Issue 4 2010Christopher P. Kenaley Abstract Four genera of the teleost family Stomiidae, the loosejaw dragonfishes, possess accessory cephalic photophores (AOs). Species of three genera, Aristostomias, Malacosteus, and Pachystomias, are capable of producing far-red, long-wave emissions (>650nm) from their AOs, a character unique among vertebrates. Aristostomias and Malacosteus posses a single far-red AO, while Pachystomias possesses anterior and posterior far-red AOs, each with smaller separate photophores positioned in their ventral margins. The purpose of this study was to establish the primary homology of the loosejaw AOs based on topological similarity of cranial nerve innervation, and subject these homology conjectures to tests of congruence under a phylogenetic hypothesis for the loosejaw dragonfishes. On the basis of whole-mount, triple-stained specimens, innervation of the loosejaw AOs is described. The AO of Aristostomias and the anterior AO of Pachystomias are innervated by the profundal ramus of the trigeminal (Tpr), while the far-red AO of Malacosteus and a small ventral AO of Pachystomias are innervated by the maxillary ramus of the trigeminal (Tmx). The largest far-red AO of Pachystomias, positioned directly below the orbit, and the short-wave AO of Photostomias are innervated by a branch of the mandibular ramus of the trigeminal nerve. Conjectures of primary homology drawn from these neuroanatomical similarities were subjected to tests of congruence on a phylogeny of the loosejaws inferred from a reanalysis of a previously published morphological dataset. Optimized for accelerated transformation, the AO innervated by the Tpr appears as a single transformation on the new topology, thereby establishing secondary homology. The AOs innervated by the Tmd found in Pachystomias and Photostomias appear as two transformations in a reconstruction on the new topology, a result that rejects secondary homology of this structure. The secondary homology of AOs innervated by the Tmx found in Malacosteus and Pachystomias is rejected on the same grounds. Two short-wave cephalic photophores present in all four genera, the suborbital (SO) and the postorbital (PO), positioned in the posteroventral margin of the orbit and directly posterior to the orbit, respectively, are innervated by separate divisions of the Tmd. The primary homologies of the loosejaw PO and SO across loosejaw taxa are proposed on the basis of similar innervation patterns. Because of dissimilar innervation of the loosejaw SO and SO of basal stomiiforms, primary homology of these photophores cannot be established. Because of similar function and position, the PO of all other stomiid taxa is likely homologous with the loosejaw PO. Nonhomology of loosejaw long-wave photophores is corroborated by previously published histological evidence. The totality of evidence suggests that the only known far-red bioluminescent system in vertebrates has evolved as many as three times in a closely related group of deep-sea fishes. J. Morphol., 2010. © 2009 Wiley-Liss, Inc. [source] Slow-tonic muscle fibers and their potential innervation in the turtle, Pseudemys (Trachemys) scripta elegansJOURNAL OF MORPHOLOGY, Issue 1 2005Robert J. Callister Abstract A description is provided of the ratio of slow-tonic vs. slow- and fast-twitch fibers for five muscles in the adult turtle, Pseudemys (Trachemys) scripta elegans. The cross-sectional area of each fiber type and an estimation of the relative (weighted) cross-sectional area occupied by the different fiber types are also provided. Two hindlimb muscles (flexor digitorum longus, FDL; external gastrocnemius, EG) were selected on the basis of their suitability for future motor-unit studies. Three neck muscles (the fourth head of testo-cervicis, TeC4; the fourth head of retrahens capitus collique, RCCQ4; transversalis cervicis, TrC) were chosen for their progressively decreasing oxidative capacity. Serial sections were stained for myosin adenosine triphosphatase (ATPase), NADH-diaphorase, and alpha-glycerophosphate dehydrogenase (,-GPDH). Conventional fiber-type classification was then performed using indirect markers for contraction speed and oxidative (aerobic) vs. glycolytic (anaerobic) metabolism: i.e., slow oxidative (SO, including slow-twitch and possibly slow-tonic fibers), fast-twitch, oxidative-glycolytic (FOG), and fast-twitch glycolytic (Fg) fibers. Slow-tonic fibers in the SO class were then revealed by directing the monoclonal antibody, ALD-58 (raised against the slow-tonic fiber myosin heavy chain of chicken anterior latissimus dorsi), to additional muscle cross sections. All five of the tested muscles contained the four fiber types, with the ATPase-stained fibers including both slow-tonic and slow-twitch fibers. The extreme distributions of SO fibers were in the predominately glycolytic TrC vs. the predominately oxidative TeC4 muscle (TrC,SO, 9%; FOG, 20%; Fg, 71% vs. TeC4,SO, 58%: FOG, 16%; Fg, 25%). Across the five muscles, the relative prevalence of slow-tonic fibers (4,47%) paralleled that of the SO fibers (9,58%). TeC4 had the highest prevalence of slow-tonic fibers (47%). The test muscles exhibited varying degrees of regional concentration of each fiber type, with the distribution of slow-tonic fibers paralleling that of the SO fibers. In the five test muscles, fiber cross-sectional area was usually ranked Fg > FOG > SO, and slow-twitch always > slow-tonic. In terms of weighted cross-sectional area, which provides a coarse-grain measure of each fiber type's potential contribution to whole muscle force, all five muscles exhibited a higher Fg and lower SO contribution to cross-sectional area than suggested by their corresponding fiber-type prevalence. This was also the case for the slow-twitch vs. slow-tonic fibers. We conclude that slow-tonic fibers are widespread in turtle muscle. The weighted cross-sectional area evidence suggested, however, that their contribution to force generation is minor except in highly oxidative muscles, with a special functional role, like TeC4. There is discussion of: 1) the relationship between the present results and previous work on homologous neck and hindlimb muscles in other nonmammalian species, and 2) the potential motoneuronal innervation of slow-tonic fibers in turtle hindlimb muscles. J. Morphol. © 2005 Wiley-Liss, Inc. [source] Lower leg muscle atrophy in ankle osteoarthritisJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 12 2006Victor Valderrabano Abstract The aim of this study was to determine changes in the lower leg muscles associated with ankle osteoarthritis. Fifteen unilateral ankle osteoarthritis patients and fifteen age-gender-matched normal subjects were assessed with clinical [osteoarthritis latency time, pain, alignment, AOFAS ankle score, ankle range of motion (ROM), calf circumference], radiological (ankle osteoarthritis grading), and muscular-physiological parameters [isometric maximal voluntary ankle torque, surface electromyography of the anterior tibial (AT), medial gastrocnemius (MG), soleus (SO), and peroneus longus (PL) muscle]. The osteoarthritis patients had increased pain (6.8 points) and reduced AOFAS score (33.7 points) compared to the control group. Compared to the contralateral healthy leg, the arthritic leg showed reduced mean dorsi-/plantar flexion ROM (16.0°), reduced mean calf circumference (2.1 cm), smaller mean dorsiflexion (16.4 Nm) and plantar flexion (15.8 Nm) torques, lower mean electromyography frequency for all muscles (AT ,22.6 Hz; MG ,27.3 Hz; SO ,25.9 Hz; PL ,28.5 Hz), and lower mean electromyography intensity in the AT [,28.0,×,103 (µv)2], MG [,13.3,×,103 (µv)2], and PL [,12.8,×,103 (µv)2]. SO mean electromyography intensity was not significantly changed [+2.0,×,103 (µv)2]. Unilateral ankle osteoarthritis is associated with atrophic changes of the lower leg muscles. This study supports previous observations on muscle dysfunction in knee osteoarthritis. © 2006 Orthopaedic Research Society. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source] Attenuation of ciclosporin-induced nephrotoxicity by dietary supplementation of seal oil in Sprague-Dawley ratsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 11 2005Wei Yang Fish oil, rich in omega-3 (n-3) polyunsaturated fatty acids (PUFAs), has been reported to attenuate nephrotoxicity induced by ciclosporin (cyclosporine A). Harp seal oil is a rich source of n-3 PUFAs. This study investigated the ability of dietary seal oil to reduce nephrotoxicity caused by ciclosporin. Sprague-Dawley rats were maintained on a standard diet (with sunflower oil as lipid, SFO) or a diet enriched with seal oil (with 85% seal oil and 15% sunflower oil as lipid, SO) for four weeks before and four weeks after intravenous administration of ciclosporin (15 mg kg,1 daily). Kidney function was assessed by measuring blood urea nitrogen, creatinine clearance, urinary N -acetyl-1-,- d -glucosaminidase, 6-keto-prostaglandin F1,, thromboxane B2 and malondialdehyde. Systolic blood pressure (SBP) was monitored. Ciclosporin concentrations in blood were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The fatty acid compositions of the diets and erythrocyte membranes were analysed by gas chromatography (GC). The results showed that nephrotoxicity was induced by ciclosporin in rats maintained on both SO and SFO diets. However, rats fed on SO diet endured less toxicity than those on SFO diet. The n-3 and n-6 PUFAs in the erythrocyte membrane of rats maintained on SO diet were found to be 10.79% and 11.93%, while those in rats maintained on SFO diet were found to be 1.67% and 22.71%, respectively. In conclusion, dietary supplementation of seal oil was found to reduce ciclosporin-induced nephrotoxicity in rats. [source] Melatonin induces tyrosine hydroxylase mRNA expression in the ventral mesencephalon but not in the hypothalamusJOURNAL OF PINEAL RESEARCH, Issue 1 2002José L Venero We have evaluated the effect of chronic administration of melatonin in terms of mRNA expression for tyrosine hydroxylase (TH), the rate-limiting enzyme in catecholamine biosynthesis, and in the terms of dopamine (DA) transporter (DAT) by means of in situ hybridization. Experimental rats received daily late afternoon injections of 1.5 mg/kg melatonin for 30 days and analysis were performed in the ventral mesencephalon including the substantia nigra (SN) and ventral tegmental area (VTA), and hypothalamus. In the ventral mesencephalon, melatonin treatment significantly induced TH mRNA levels in individual dopaminergic neurons in SN and VTA. In contrast, DAT mRNA levels remained at control levels. Striatal synaptosomal DA uptake was not modified by melatonin treatment as compared with controls. Analysis of glutamic acid decarboxylase (GAD) mRNA in SN, the biosynthetic enzyme for GABAergic neurons, revealed no effect of melatonin treatment on mRNA levels for this marker. In the hypothalamus, we performed mRNA quantitation for TH in arcuate nucleus (Arc) and supraoptic nucleus (SO). Melatonin treatment failed to alter mRNA levels in either area. We detected weak but significant mRNA levels for DAT in Arc, SO, zona incerta (ZI) and periventricular hypothalamic nucleus (Pe). However, because of the low levels of mRNA in hypothalamic areas we were unable to perform a reliable measurement of DAT mRNA levels in response to melatonin treatment. We conclude that melatonin administration, that combines antioxidant capacity and a tissue-specific TH inducing effect, may be useful as a pharmacological agent to protect dopaminergic neurons from degeneration. [source] Estrogen-Dependent Enhancement of NO Production in the Nucleus Tractus Solitarius Contributes to Ethanol-Induced Hypotension in Conscious Female RatsALCOHOLISM, Issue 2 2009Guichu Li Background:, Our previous pharmacological and cellular studies showed that peripheral (cardiac and vascular) nitric oxide synthase (NOS)-derived NO is implicated in the estrogen (E2)-dependent hypotensive action of ethanol in female rats. The objective of this study was to test the hypothesis that enhanced NO production in the nucleus tractus solitarius (NTS) is implicated in the E2 -dependent hypotensive action of ethanol. Methods:, To achieve this goal, we utilized in vivo electrochemistry to measure real time changes in neuronal NO to investigate the acute effects of intragastric ethanol (0, 0.5, or 1 g/kg) on NO in NTS neurons, blood pressure (BP), and heart rate (HR) in conscious female rats in the absence (ovariectomized, OVX, rats) or presence of E2. Results:, In sham operated (SO) rats, ethanol elicited dose-related increase in NTS NO and reduction in BP. These neurochemical and BP effects of ethanol were absent in OVX rats. Whether the neurochemical effect of ethanol and the associated hypotension are dependent on rapid E2 signaling was investigated. In OVX rats pretreated, 30 minutes earlier, with E2 (1 ,g/kg), intragastric ethanol (1 g/kg) increased NTS NO and reduced BP and these responses were comparable to those obtained in SO rats. Conclusions:, The present findings suggest that increased production of NO in NTS neurons contributes to ethanol-evoked hypotension in female rats. Further, ethanol enhancement of neuronal NO production in the brainstem is dependent on rapid E2 signaling. [source] | ||||||||||||||||||||||||||||||||||||||||||||||