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Stearic Acid (stearic + acid)
Selected AbstractsInteraction of Stearic Acid Deposited on Silicon Samples With Ar/N2 and Ar/O2 Atmospheric Pressure Microwave Post-dischargesPLASMA PROCESSES AND POLYMERS, Issue S1 2009Cédric Noël Abstract In this work, the interactions of a stearic acid film deposited on silicon by spin coating with the post-discharge of an Ar/N2 or Ar/O2 atmospheric pressure microwave plasma are studied. Sample surface before and after plasma treatment is analysed by means of different surface analysis methods (water contact angle measurements, XPS, ToF-SIMS and FTMS). Both plasma treatments modify the surface but with a higher etching rate for Ar/O2 post-discharges. The creation of double carbon bonds CC is observed during the treatments, with a higher quantity after Ar/N2 treatments. The mechanisms leading to modifications of stearic acid are discussed. [source] Cryotolerance of Bovine Blastocysts is Affected by Oocyte Maturation in Media Containing Palmitic or Stearic AcidREPRODUCTION IN DOMESTIC ANIMALS, Issue 1 2009MA Shehab-El-Deen Contents In this study, non-esterified fatty acids (NEFAs) were added during in vitro maturation at concentrations measured previously in follicular fluid (FF) of high-producing dairy cows in a negative energy status to evaluate their subsequent effect on the embryos cryotolerance. Oocytes were matured for 24 h in serum-free media with or without (negative control) the addition of NEFAs dissolved in ethanol or ethanol alone (positive control). Matured oocytes were fertilized and cultured for 7 days in synthetic oviduct fluid medium supplemented with 5% FCS. Embryos that had at least reached the blastocyst stage were vitrified by open pulled straw (OPS) vitrification. Addition of palmitic (C16 : 0) or stearic acid (C18 : 0) during oocyte maturation had significant negative effects on embryo cryotolerance, whereas ethanol or oleic acid (C18 : 1) had no effect. These in vitro results suggest that high NEFA concentrations in FF during a period of negative energy balance in high-yielding dairy cows can have carry-over effects on embryo quality. [source] Letter to the Editor: Is Stearic Acid a Wholesome Substitute for Trans Fatty Acids?COMPREHENSIVE REVIEWS IN FOOD SCIENCE AND FOOD SAFETY, Issue 4 2008Rafael Monge-Rojas PhD No abstract is available for this article. [source] Structured lipids from rice bran oil and stearic acid using immobilized lipase from Rhizomucor mieheiEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 1 2008Rajni Chopra Abstract The major objective of the present study was to prepare structured lipids rich in stearic acid from rice bran oil (RBO) using immobilized lipase (IM,60) from Rhizomucor miehei. The effects of incubation time and temperature, substrate molar ratio, and enzyme load on incorporation of stearic acid were studied. Acidolysis reactions were performed in hexane. Pancreatic lipase-catalyzed sn -2 positional analysis and tocopherol analyses were performed before and after enzymatic modification. The kinetics of the reaction was studied and maximum incorporation of stearic acid was observed at 6,h, at 37,°C, when the triacylglycerol and stearic acid molar ratio was maintained at 1,:,6 and the enzyme concentration was 10% of total substrates weight. Stearic acid in RBO after acidolysis was increased from 2.28 to 48.5%, with a simultaneous decrease in palmitic, oleic and linoleic acids. HPLC analysis of tocopherols and tocotrienols was carried out and their content in modified RBO was not significantly affected compared to that of native RBO. The oryzanol content of the modified RBO was reduced from 1.02 to 0.68%. Melting and crystallizing characteristics of the modified fat were studied using differential scanning calorimetry. The total solid fat content at 25,°C increased from 26.12 to 34.8% with an increase in stearic acid incorporation into RBO from 38 to 48%, but it was comparatively less than for cocoa butter and vanaspati. However, the modified RBO completely melted at 37,°C and was useful as plastic fat for various culinary purposes, bakery and confectionary applications. The results of the present study indicated that structured lipids prepared from RBO rich in stearic acid retained their beneficial nutraceuticals; in addition, they do not contain any trans fatty acids. [source] Fatty acid incorporation in endothelial cells and effects on endothelial nitric oxide synthaseEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 9 2007S. Couloubaly Abstract Background The nature of fatty acids provided by the diet as well as plasma lipid metabolism can modify the composition and properties of plasma membrane and thus the activity of membrane proteins. In humans, as well as in experimental models, diabetes is associated with both an alteration in serum lipid profile and a documented endothelial dysfunction. This in vitro study investigated on an immortalized human endothelial cell line (EA.hy 926) the specific effects of several free fatty acids (FFAs) on the composition of cellular membranes and the regulation of endothelial nitric oxide synthase (eNOS). Materials and methods 0·1% of lipid deprived serum was added to the incubation medium with 25 mm glucose in order to study the effects of individual fatty acids: myristic acid, palmitic acid, stearic acid, oleic acid or linoleic acid at 100 µm bound with albumin. The effects of the FFAs on the endothelial nitric oxide synthase were investigated on mRNA level by quantitative PCR, on protein level and Ser1177 phosphorylation by Western blot and on enzymatic activity on living cells using radiolabelled arginine. Results Free linoleic acid increased the membrane content in n-6 fatty acids (mainly C18: n-6 and its metabolites) with a decrease in saturated and monounsaturated fatty acids. These conditions decreased the basal eNOS activity and reduced the phosphorylation of eNOS-Ser1177 due to activation by histamine. Free palmitic acid enriched the membranes with 16 : 0 with a slight decrease in monounsaturated fatty acids. These conditions increased eNOS activation without increasing Ser1177 phosphorylation upon histamine activation. The addition of the other FFAs also resulted in modifications of membrane composition, which did not to affect eNOS-Ser1177 phosphorylation. Conclusion Among the fatty acids used, only modification of the membrane composition due to linoleic acid supply disturbed the basal enzymatic activity and Ser1177 phosphorylation of eNOS in a way that limited the role of histamine activation. Linoleic acid might involve the dysfunction of both eNOS basal activity and its phosphorylation status and may then contribute to an impaired vasodilatation in vivo. [source] Structured lipids from rice bran oil and stearic acid using immobilized lipase from Rhizomucor mieheiEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 1 2008Rajni Chopra Abstract The major objective of the present study was to prepare structured lipids rich in stearic acid from rice bran oil (RBO) using immobilized lipase (IM,60) from Rhizomucor miehei. The effects of incubation time and temperature, substrate molar ratio, and enzyme load on incorporation of stearic acid were studied. Acidolysis reactions were performed in hexane. Pancreatic lipase-catalyzed sn -2 positional analysis and tocopherol analyses were performed before and after enzymatic modification. The kinetics of the reaction was studied and maximum incorporation of stearic acid was observed at 6,h, at 37,°C, when the triacylglycerol and stearic acid molar ratio was maintained at 1,:,6 and the enzyme concentration was 10% of total substrates weight. Stearic acid in RBO after acidolysis was increased from 2.28 to 48.5%, with a simultaneous decrease in palmitic, oleic and linoleic acids. HPLC analysis of tocopherols and tocotrienols was carried out and their content in modified RBO was not significantly affected compared to that of native RBO. The oryzanol content of the modified RBO was reduced from 1.02 to 0.68%. Melting and crystallizing characteristics of the modified fat were studied using differential scanning calorimetry. The total solid fat content at 25,°C increased from 26.12 to 34.8% with an increase in stearic acid incorporation into RBO from 38 to 48%, but it was comparatively less than for cocoa butter and vanaspati. However, the modified RBO completely melted at 37,°C and was useful as plastic fat for various culinary purposes, bakery and confectionary applications. The results of the present study indicated that structured lipids prepared from RBO rich in stearic acid retained their beneficial nutraceuticals; in addition, they do not contain any trans fatty acids. [source] Characterization of a hemocyte intracellular fatty acid-binding protein from crayfish (Pacifastacus leniusculus) and shrimp (Penaeus monodon)FEBS JOURNAL, Issue 13 2006Irene Söderhäll Intracellular fatty acid-binding proteins (FABPs) are small members of the superfamily of lipid-binding proteins, which occur in invertebrates and vertebrates. Included in this superfamily are the cellular retinoic acid-binding proteins and retinol-binding proteins, which seem to be restricted to vertebrates. Here, we report the cDNA cloning and characterization of two FABPs from hemocytes of the freshwater crayfish Pacifastacus leniusculus and the shrimp Penaeus monodon. In both these proteins, the binding triad residues involved in interaction with ligand carboxylate groups are present. From the sequence and homology modeling, the proteins are probably FABPs and not retinoic acid-binding proteins. The crayfish transcript (plFABP) was detected at high level in hemocytes, hepatopancreas, intestine and ovary and at low level in hematopoietic tissue and testis. Its expression in hematopoietic cells varied depending on the state of the crayfish from which it was isolated. Expression was 10,15 times higher in cultures isolated from crayfish with red colored plasma, in which hemocyte synthesis was high, if retinoic acid was added to the culture medium. In normal colored crayfish, with normal levels of hemocytes, no increase in expression of p1FABP was detected. Two other putative plFABP ligands, stearic acid and oleic acid, did not have any effect on plFABP expression in hematopoietic cells. These results suggest that retinoic acid-dependent signaling may be present in crustaceans. [source] Sulfatide with short fatty acid dominates in astrocytes and neuronsFEBS JOURNAL, Issue 8 2006Giorgis Isaac Glycosphingolipids are located in cell membranes and the brain is especially enriched. We speculated that the subcellular location of glycosphingolipids depends on their fatty acid chain length because their sugar residues are constant, whereas fatty acid chain length can vary within the same molecule. To test this hypothesis we analysed the glycosphingolipid sulfatide, which is highly abundant in myelin and has mostly long fatty acids. We used a negative ion electrospray tandem mass spectrometry precursor ion scan to analyse the molecular species of sulfatide in cultured astrocytes and a mouse model of the human disease metachromatic leukodystrophy. In these arylsulfatase A (ASA)-deficient mice sulfatide accumulates intracellularly in neurons and astrocytes. Immunocytochemistry was also performed on cultured astrocytes and analysed using confocal laser scanning microscopy. Analyses of the molecular species showed that cultured astrocytes contained sulfatide with a predominance of stearic acid (C18), which was located in large intracellular vesicles throughout the cell body and along the processes. The same was seen in ASA-deficient mice, which accumulated a higher proportion (15 mol% compared with 8 mol% in control mice) of sulfatide with stearic acid. We conclude that the major fatty acid composition of sulfatide differs between white and grey matter, with neurons and astrocytes containing mostly short-chain fatty acids with an emphasis on stearic acid. Based on our results, we speculate that the fatty acid chain length of sulfatide might determine its intracellular (short chain) or extracellular (long chain) location and thereby its functions. [source] Oligo(triacetylene) Derivatives with Pendant Long Alkyl ChainsHELVETICA CHIMICA ACTA, Issue 6 2004Jean-François Nierengarten Substituted (E)-2-(ethynyl)but-2-ene and (E)-hex-3-ene-1,5-diyne derivatives 6 and 10, respectively, were prepared by dicyclohexylcarbodiimide(DCC)-mediated esterification of tris(dodecyloxy)benzoic acid (4) with (E)-2-[(triisopropylsilyl)ethynyl]but-2-ene-1,4-diol (3) and (E)-2,3-bis[(trimethylsilyl)ethynyl]but-2-ene-1,4-diol (8), respectively, followed by deprotection with Bu4NF in wet THF (Schemes,1 and 2). Oligomerization reactions of diyne derivative 10 were attempted by treatment with the Hay catalyst in the presence of mono-alkyne 6 as an end-capping reagent. Under these conditions, only compound 7 resulting from the homocoupling of 6 (Scheme,1), and polymers of 10 were obtained due to the difference in reactivity of the alkyne groups in 6 and 10. In contrast, when phenylacetylene was used as the stopper, the oligomerization of 10 afforded a mixture of end-capped oligomers, from which 11,13 were isolated by column chromatography (Scheme,3). The poly(triacetylenes) (PTA) 16,18 were prepared in a similar manner starting from diol 8 and stearic acid (Schemes,4 and 5). Whereas the end-capped monomers and dimers 11, 12, 16, and 17 with pendant long alkyl chains do not exhibit any liquid-crystalline behavior, the trimeric derivatives 13 and 18 show mesomorphic properties, thus demonstrating that the poly(triacetylene) backbone can behave as a mesogenic unit. [source] Sex difference in the liver of hepatocyte-specific Pten-deficient mice: A model of nonalcoholic steatohepatitisHEPATOLOGY RESEARCH, Issue 6 2009Yumiko Anezaki Aim:, Nonalcoholic fatty liver disease (NAFLD) is considered to be a public health problem worldwide. NAFLD is more prevalent in men than in women. Tamoxifen, a potent estrogen receptor antagonist, causes nonalcoholic steatohepatitis (NASH), a severe form of NAFLD. Thus, there may be a sex difference that is dependent on estrogens in NAFLD and NASH. Hepatocyte-specific Pten-deficient mice exhibit hepatic lesions analogous to NASH and are considered to be a clinical model of NASH. We aimed to shed light on any sex differences in the hepatic lesions of Pten-deficient mice and the underlying mechanisms. Methods:, At 40 weeks, livers from male and female Pten-deficient mice were processed for measuring lipid content, genes expression analysis, and histological examination. Level of serum reactive oxygen species (ROS) was also determined. Seventy-six-week-old mice were used in tumor burden experiments. Results:, Hepatic steatosis, inflammation, and even carcinogenesis in Pten-deficient mice were attenuated in females compared to males. Attenuated fatty liver in females was ascribed to inactivation of sterol regulatory element binding protein-1c. Hepatic inflammation in females was suppressed via decreased ROS with increased antioxidant gene expression and decreased proinflammatory cytokine production. Anti-cancer effect in female mice was, at least in part, due to the significantly lower ratio of oleic to stearic acid in the liver. Conclusions:, Hepatic lesions in Pten-deficient mice were attenuated in females compared to males, as were human NAFLD and NASH. Some of the underlying mechanisms in sex difference appeared to be due to the change of gene expression, dependent on estrogens. [source] Effect of Long Chain Fatty Acids on Organocatalytic Aqueous Direct Aldol ReactionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2009Nobuyuki Mase Abstract In an organocatalyzed, aqueous direct aldol reaction, the addition of a long chain fatty acid (1,mol%) such as stearic acid or erucic acid improved the aldol product yield and the enantioselectivity with low catalyst loading (1,mol%). The small particle size of the emulsion (less than 1,,m) was a key to the enhanced reactivity as shown by dynamic light scattering (DLS) analyses. [source] Effect of Planting Date on Seed Yield, Oil Content and Fatty Acid Composition of Safflower (Carthamus tinctorius) Cultivars Grown in the Mediterranean Region of TurkeyJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 5 2003B. Samanc Abstract A study was conducted to investigate the effect of different planting dates (25 April, 5 May and 15 May 1998 and 30 April, 15 May and 25 May 1999) on the seed yield, oil content and fatty acid composition of three safflower (Carthamus tinctorius) cultivars (Yenice 5-38, Dincer 5-118 and 5-154) grown in fields of the research facility of Akdeniz University in Antalya, Turkey. While seed yield, oil content, and palmitic acid, stearic acid, and oleic acid contents decreased, linoleic acid content increased from 50.86 to 55.72 % with delay in planting date. The effect of genotype on fatty acids was greater than that of environment. [source] Kinetics of microbial hydrogenation of free linoleic acid to conjugated linoleic acidsJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2008H. Xu Abstract Aims:, To investigate the ability of selected probiotic bacterial strains to produce conjugated linoleic acid (CLA) and also to estimate the biohydrogenation kinetics of Lactobacillus acidophilus on the production of CLA from free linoleic acid (LA). Methods and Results:, Six probiotic bacteria, Lact. paracasei, Lact. rhamnosus GG, Lact. acidophilus ADH, and Bifidobacterium longum B6, Lact. brevis, and Lact. casei, were used to examine their ability to convert LA to CLA. LA tolerance was evaluated by addition of different LA concentrations in MRS broth. Lact. acidophilus showed the major tolerant to LA and the greatest CLA-producing ability (36,48 ,g ml,1 of CLA). The rate-controlling steps were k2 and k1 for the addition of 1 and 3 mg ml,1 of LA, respectively. The percentage of CLA conversion was higher in MRS broth supplemented with 1 mg ml,1 (65%) than 3 mg ml,1 (26%). Conclusion:, The results provide useful information and new approach for understanding the biohydrogenation mechanisms of CLA production. Significance and Impact of the Study:, This study would help elucidate the pathway from LA to stearic acid (SA), known as biohydrogenation. In addition, the use of selected probiotic bacteria might lead to a significant improvement in food safety. [source] Effects of epoxidized sunflower oil on the mechanical and dynamical analysis of the plasticized poly(vinyl chloride)JOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Badra Bouchareb Abstract Epoxidized soybean oil (ESBO), is one of the most commonly used epoxides because of its typical combined roles as a plasticizer and heat stabilizer. In this study, a novel plasticizer of poly(vinyl chloride) (PVC) resins, epoxidized sunflower oil (ESO), was synthesized, and its performance was evaluated. ESO was designed to act as a coplasticizer and a heat stabilizer like ESBO. ESO is used as organic coplasticizer for plasticized PVC containing Ca and Zn stearates as primary stabilizers and stearic acid as lubricant. Di-(2-ethylhexyl) phthalate (DEHP), a conventional plasticizer for PVC, was partially replaced by ESO. Mechanical properties (tensile and shore D hardness) were investigated. The performance of ESO to ESB0 (20 g) for comparison, indicated that ESO could be used as secondary plasticizer for PVC in combination with DEHP. All mechanical and dynamical properties of plasticized PVC sheets varied with the oxirane oxygen of the ESO. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Heparin release from slippery-when-wet guide wires for intravascular useJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 6 2002Camiel C. L. Peerlings Abstract Thin metallic wires with an adherent hydrophilic/ lubricious polymeric coating were manufactured in a new extrusion-like procedure. This procedure is part of a novel and efficient way of assembling lubricious guide wires for intravascular interventions, such as percutaneous transluminal angioplasty. It is reported that heparin can readily be incorporated in the hydrophilic coating. A set of heparin-containing guidewire models was made and studied in detail. This showed that (i) immersion of the guide-wire models in an aqueous environment leads to release of heparin from their surface; (ii) the presence of heparin in the coating does not impede the lubricity of the coils; (iii) addition of stearic acid in the coating, next to heparin, does not influence the lubricity of the guide-wire models. Two different charges of heparin (designated heparin-low and heparin-high) were incorporated in the coating. It is discussed that release of heparin from the surface of medical devices (e.g. guide wires and catheters) is much more effective than systemic heparinization, basically because dissolved heparin molecules have a much larger probability of simply passing a medical device's surface (axial convection) rather than contacting it (radial diffusion). © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 692,698, 2002 [source] Effects of Trans and Conjugated LC N-3 Polyunsaturated Fatty Acids on Lipid Composition and Abdominal Fat Weight in RatsJOURNAL OF FOOD SCIENCE, Issue 8 2008T. Okada ABSTRACT:,Trans and conjugated fatty acids may exhibit either beneficial or detrimental bioactive effects depending on their metabolic properties. This study was conducted to elucidate if isomerization and conjugation of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) demonstrate more favorable bioactivity on lipid metabolism compared to unmodified EPA and DHA. The effects of dietary intake of trans and conjugated forms of EPA and DHA on lipid metabolism were evaluated in animal trials and compared to a control group fed soybean oil. None of the experimental diets showed significant differences from the control in terms of body weight; however, the white adipose tissue weight of rodents fed trans DHA, conjugated EPA (CEPA), and conjugated DHA (CDHA) was significantly lower than the control. Triacylglycerol levels in plasma were significantly decreased in groups fed trans DHA (17.2 mg/dL) and CDHA (31.9 mg/dL) relative to the control (51.3 mg/dL). The total cholesterol concentrations were significantly lower than the control (68.0 mg/dL) in all experimental groups (47.3 to 53.7 mg/dL) except CEPA (58.3 mg/dL). Fatty acid compositions of lipids extracted from rodent livers were influenced by the dietary fatty acid profiles, with all groups showing higher concentrations of stearic acid and lower levels of linoleic acid compared to the control. Rodents fed trans DHA did not have detectable levels of these fatty acid isomers in their livers, suggesting either quick metabolism or a difficulty with bio-absorption. [source] Combined application of extrusion-spheronization and hot-melt coating technologies for improving moisture-proofing of herbal extractsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 5 2010Hao Chen Abstract The aim of this research was to investigate the moisture-proofing effect and its mechanism for herbal extracts using extrusion-spheronization combined with hot-melt coating. Guizhi Fuling (GF) compound herbal extract with high hygroscopicity was used as a model drug. In the process of extrusion-spheronization, pellets containing 100% GF were prepared, and then coated with hot-melt coating material using a traditional coating pan. The moisture sorption data for GF were determined by storage at a series of different relative humidities. When the pellets were coated with a 96:4 mixture of stearic acid and polyethylene glycol 6000, the cumulative drug release was over 90% at 45,min while the moisture content was 4.9% at 75% RH within 10 days. These pellets have better moisture-proofing than those coated with Opadry AMB at the same coating level due to a different moisture sorption mechanism. The moisture sorption behavior of the hot-melt coating can be attributed to water vapor diffusion via a porous matrix system, while the Opadry AMB coating system involved a swelling controlled system. The Higuchi model was the best fit for the moisture sorption of the hot-melt coating in all formulations whereas the Opadry AMB coating fitted the Nuttanan model. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99: 2444,2454, 2010 [source] Apoptosis inducing activity of viscin, a lipophilic extract from Viscum album L.JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 1 2005K. Urech Detection of antiproliferative activity and bioactivity-guided fractionation of viscin, a lipophilic extract from Viscum album L., led to the isolation of betulinic acid, oleanolic acid and ursolic acid as active components. Viscin, betulinic acid, oleanolic acid and ursolic acid inhibited growth and induced apoptotic cell death in Molt4, K562 and U937 leukaemia cells. The growth inhibitory effect of viscin was more pronounced in Molt4 and U937 cells (IC50 (concentration that inhibited cell proliferation by 50%): 118 ± 24 and 138 ± 24 ,g mL,1) than in K562 cells (IC50: 252 ± 37 ,g mL,1). Oleanolic acid was the least effective in all cell lines (7.5,45.5% inhibition at 10 ,g mL,1) and ursolic acid the most active in Molt4 and U937 cells (81.8 and 97.8% inhibition, respectively, at 5 ,g mL,1). A dose-dependent loss of membrane phospholipid asymmetry associated with apoptosis was induced in all cell lines as shown in flow cytometry by the externalization of phosphatidylserine and morphological changes in cell size and granularity. There were differences in individual cell lines' response towards the apoptosis-inducing effect of viscin, betulinic acid, oleanolic acid and ursolic acid. The triterpenoids ,-amyrin, ,-amyrinacetate, lupeol, lupeolacetate, ,-sitosterol and stigmasterol, and the fatty acids oleic acid, linoleic acid, palmitic acid and stearic acid were also present in the lipophilic extract. [source] Effect of ,-butyrobetaine on fatty liver in juvenile visceral steatosis miceJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 4 2001Yasuhiko Higashi We pharmacokinetically examined the effect of ,-butyrobetaine, a precursor of l -carnitine, on the change of fatty acid metabolism in juvenile visceral steatosis (JVS) mice, which have systemic l -carnitine deficiency due to lack of l -carnitine transporter activity. The concentrations of total free fatty acid (FFA), palmitic acid and stearic acid in the liver of JVS mice were significantly higher than those in wild-type mice. After intravenous administration of ,-butyrobetaine (50 mg kg,1), the concentration of l -carnitine in the plasma of JVS mice reached about twice that of the control level and levels in the brain, liver and kidney were also significantly increased, whereas those in wild-type mice hardly changed. Although the plasma concentrations of FFA in both types of mice were unchanged after administration of ,-butyrobetaine, the concentrations of palmitic acid and stearic acid were significantly decreased. In particular, the liver concentration of FFA in JVS mice was decreased to the wild-type control level, accompanied by significant decreases in long-chain fatty acids, palmitic acid and stearic acid, whereas those in wild-type mice were not changed. These results suggest that ,-butyrobetaine can be taken up into organs, including the liver, of JVS mice, and transformed to l -carnitine. Consequently, administration of ,-butyrobetaine may be more useful than that of l -carnitine itself for treatment of primary deficiency of carnitine due to a functional defect of the carnitine transporter. [source] Chemical composition of mate tea leaves (Ilex paraguariensis): A study of extraction methodsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 18 2006Rosângela Assis Jacques Abstract The objective of this work was to investigate the extraction of Ilex paraguariensis leaves by means of three extraction techniques: pressurized liquid extraction (PLE, also called accelerated solvent extraction , ASE), maceration, and sonication. Samples of mate tea leaves were collected from an experiment conducted under agronomic control at Indústria e Comércio de Erva-Mate Bar,o LTDA, Brazil. Six solvents with increasing polarities (n -hexane, toluene, dichloromethane, ethyl acetate, acetone, and methanol) were used in this investigation. Chemical analysis of the extracts was performed by GC coupled with a mass spectrometer detector. The identification and quantification were accomplished by coinjections of certified standards. The results showed that no significant differences in the qualities of the extracts were noticed regarding the extraction methods. On the other hand, the PLE technique was found to be more effective for the extractions of caffeine, phytol, palmitic, and stearic acid. The use of PLE led to a significant decrease in the total extraction time, amount of solvent consumption, and manipulation of samples compared to maceration and ultrasound-assisted extraction methods. [source] Improved Hydration Resistance of Synthesized Magnesia,Calcia Clinker by Surface ModificationJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2004Shujiang Chen Hydration resistance of synthesized MgO,CaO clinker was improved by surface modification using oleic acid, stearic acid, or complex acids as modifiers, with phosphoric acid as a reference. Unmodified and modified samples were evaluated using a powdering resistance test, weight change test, and flowability test. The remarkable effects of the modifiers on the hydration resistance and flowability of the clinker were manifested, and the complex modifier caused the most significant effect. The mechanism involved the formation of calcium-containing films on the surfaces of the clinker particles, which protected them from hydration. The flowability of the clinker also increased with improved hydration resistance because of the decreased bonded-moisture content. Comparison of infrared spectra between unmodified and modified samples confirmed the formation of surface films. [source] Pastoral and species flavour in lambs raised on pasture, lucerne or maizeJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 2 2003Owen A Young Abstract Variations in diet, age and castration were employed to generate a range of flavours that were chemically analysed to find the cause of ,pastoral' flavour in sheepmeat and its relationship to species flavour. Lambs were raised on pasture (ram or castrate) or on a maize-based or lucerne-based concentrate diet (ram only). They were slaughtered at 132 and 232 days. Fat from animals raised on concentrates had lower proportions of fat-hardening stearic acid and higher proportions of oxidation-prone fat-softening oleic and linoleic acids. Concentrations of species-characterising short branched-chain fatty acids (BCFAs), typified by 4-methyloctanoic acid, were lower for pasture-fed lambs, particularly at 232 days, although between-animal variation was high. Castration did not statistically affect BCFA concentration at this age. Correlations between BCFAs and testes weight were not significant, suggesting that they were not acting as sex pheromones. Concentrations of 3-methylindole (skatole) in perirenal fat were higher for the pasture diet at both slaughter dates. Concentrations of 4-methylphenol in the fat were not affected by diet. However, 3-methylphenol was more abundant in pasture treatments. A sensory panel found that the intensity of ,sheepmeat' flavour was higher for pasture-raised animals, but that associations of ,barnyard' flavour (which has been linked to pastoral flavour) with diet were more complex. The issue was resolved by fat sniffing. Panel responses to heated subcutaneous fat were recorded as frequency of descriptive terms drawn from a limited lexicon. Volatiles from fats pooled by treatment were resolved on a gas chromatographic column whose effluent was monitored by odourport sniffing. Compounds were identified by parallel chromatographic/mass spectrometric runs. The headspace concentrations of these compounds were then measured for individual animals. These data were related to frequency data by the principal component method. ,Mutton' and ,sheepmeat' odour notes were clearly linked to indoles (skatole particularly) and, to a lesser extent, methylphenol, setting these notes apart from ,lamb', an odour note more associated with lucerne and maize diets through higher concentrations of BCFAs. It was concluded that 3-methylindole was the major cause of pastoral flavour in sheepmeat, and that fat oxidation products represented a background flavour that varied quantitatively but not qualitatively with fatty acid profile. © 2002 Society of Chemical Industry [source] Micro-fabrication and monitoring of three-dimensional microstructures based on laser-induced thermoplastic formationMICROSCOPY RESEARCH AND TECHNIQUE, Issue 10 2009Leyan Wang Abstract This article reports a novel laser-induced micro-fabrication method and its monitoring system for three-dimensional (3D) microstructures. The mechanism of the method is that a small zone of thermoplastic material melted by laser heating grows in liquid surrounding environment, solidifying into a convex microstructure, such as micro-dot or micro-pillar. A laser diode (808 nm) with maximum power output of 130 mW is used as power source, and a kind of paraffin mixed with stearic acid and paint serves as the thermoplastic material for 3D microstructure formation experiments. A light microscope system consisting of a charge-coupled device (CCD) and a computer is utilized to realize real-time observation of the micro-fabricating process. The distribution of local temperature rise on material surface created by laser irradiation is simulated. The effects of liquid environment on microstructure formation have been theoretically analyzed and experimentally studied. Experiments are further carried out to investigate the relationship between laser spot and fabricated microstructures. The results indicate that the widths of micro-dots or micro-pillars are mostly determined by the size of focal spot, and their heights increase with the enlargement of laser power density. With this method, a micro-dot array of Chinese characters meaning "China" has been successfully fabricated through computer programming. This method has the advantages of implementing direct, mask-less, real-time and inexpensive 3D microstructure fabrication. Therefore, it would be widely applied in the fields of micro/nano-technology for practical fabrication of different kinds of 3D microstructures. Microsc. Res. Tech., 2009. © 2009 Wiley-Liss, Inc. [source] Expression of a cDNA encoding palmitoyl-acyl carrier protein desaturase from cat's claw (Doxantha unguis-cati L.) in Arabidopsis thaliana and Brassica napus leads to accumulation of unusual unsaturated fatty acids and increased stearic acid content in the seed oilPLANT BREEDING, Issue 2 2007M. Bondaruk Abstract A cDNA encoding palmitoyl-acyl carrier protein (ACP)-desaturase from cat's claw (Doxantha unguis-cati L.) was expressed in Arabidopsis thaliana and Brassica napus L. with the goal of decreasing the saturated fatty acid (FA) content of the seed oil. In general, transformation of Arabidopsis resulted in a greater change in the FA composition of the seed oil than for B. napus. An increase in palmitoleic acid (16:1cis,9) was obtained in transgenic lines, suggesting that the 16:0-ACP-desaturase cDNA was expressed in the manner originally intended. Other effects on lipid metabolism, however, were observed in the seed of transgenic plants. In Arabidopsis, there was a large increase in the proportions of cis -vaccenic acid (18:1cis,11) and cis -13-eicosenoic acid (20:1cis,13), possibly generated through elongation of 16:1cis,9. Elongation of 18:1cis,11 to 20:1cis,13, however, was not observed in B. napus indicating that certain aspects of lipid metabolism in the model plant, Arabidopsis, may not apply to B. napus. As well, the appearance of 18:1cis,11 was accompanied by a decrease in the proportion of oleic acid (18:1cis,9). Although the introduced ACP-desaturase resulted in synthesis of some unsaturated FAs, the overall saturated FA content was maintained at similar levels to the control or was enhanced. Increased levels of saturation were mainly associated with an increase in stearic acid, which unlike 16:0, is considered non-atherogenic. The results suggest that a mechanism exists further downstream in oil biosynthesis to counteract the decrease in saturation brought about by the 16:0-ACP-desaturase action. [source] Interaction of Stearic Acid Deposited on Silicon Samples With Ar/N2 and Ar/O2 Atmospheric Pressure Microwave Post-dischargesPLASMA PROCESSES AND POLYMERS, Issue S1 2009Cédric Noël Abstract In this work, the interactions of a stearic acid film deposited on silicon by spin coating with the post-discharge of an Ar/N2 or Ar/O2 atmospheric pressure microwave plasma are studied. Sample surface before and after plasma treatment is analysed by means of different surface analysis methods (water contact angle measurements, XPS, ToF-SIMS and FTMS). Both plasma treatments modify the surface but with a higher etching rate for Ar/O2 post-discharges. The creation of double carbon bonds CC is observed during the treatments, with a higher quantity after Ar/N2 treatments. The mechanisms leading to modifications of stearic acid are discussed. [source] Effects of stearic acid on the interface and performance of polypropylene/superfine down powder compositesPOLYMER COMPOSITES, Issue 12 2009Xin Liu To manufacture the hygroscopic sheets available for functional application, superfine down powder (SDP) and stearic acid modified superfine down powder (MSDP) were, respectively, blended and extruded with polypropylene (PP) to produce composite pellets, and the extruded pellets were hot-pressed into composite sheets. The chemical reaction between SDP and stearic acid was characterized using the attenuated total reflection attachment on the Fourier transform infrared. PP/MSDP composites showed more uniform powder dispersion in PP matrix, higher compatibility, and better mechanical properties than that of PP/SDP composites, which showed an evident decrease in tensile strength and elongation at break compared with pure PP. It was worth noting that the Young's modulus of PP/SDP composites was higher than that of pure PP, but lower than that of PP/MSDP composites. The addition of SDP led to a large increase in water absorption of PP/SDP composites. However, the water absorption of PP/MSDP composites decreased slightly compared with that of PP/SDP composites. Furthermore, the effects of SDP and MSDP on the microstructural and thermal properties of different composites were also investigated, respectively. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers [source] Properties of polypropylene/aluminum trihydroxide composites containing nanosized organoclayPOLYMER ENGINEERING & SCIENCE, Issue 12 2005Noora Ristolainen Montmorillonite is a promising substitute for aluminum trihydroxide in flame-retardant polypropylene/aluminum trihydroxide (PP/ATH) composites. Study was made of the partial substitution of organoclay for ATH in PP/ATH composites. The total concentration of filler was kept at 30 wt%. The composites were compatibilized with two types of compatibilizer: commercial maleic anhydride functionalized polypropylene (PP- g -MA) and hydroxyl-functionalized polypropylene (PP- co -OH) prepared with metallocene catalyst. The effect of compatibilization on the morphology was studied by the transmission electron microscopy and the scanning electron microscopy. Mechanical properties were characterized by tensile and impact measurements, and flammability properties with a cone calorimeter. Addition of compatibilizer and stearic acid (SA) treatment of the ATH particles contributed to the dispersion of the fillers. Both compatibilizers produced organoclay with exfoliated structure and improved adhesion between the fillers and the matrix. Toughness improved and decomposition and flammability were reduced. POLYM. ENG. SCI. 45:1568,1575, 2005. © 2005 Society of Plastics Engineers [source] Using nondenaturing mass spectrometry to detect fortuitous ligands in orphan nuclear receptorsPROTEIN SCIENCE, Issue 4 2003Noelle Potier Abstract Nondenaturing electrospray mass spectrometry (ESI-MS) has been used to reveal the presence of potential ligands in the ligand-binding domain (LBD) of orphan nuclear receptors. This new approach, based on supramolecular mass spectrometry, allowed the detection and identification of fortuitous ligands for the retinoic acid-related orphan receptor , (ROR,) and the ultraspiracle protein (USP). These fortuitous ligands were specifically captured from the host cell with the proper stoichiometry. After organic extraction, these molecules have been characterized by classic analytical methods and identified as stearic acid for ROR, and a phosphatidylethanolamine (PE) for USP, as confirmed by crystallography. These molecules act as "fillers" and may not be the physiological ligands, but they prove to be essential to stabilize the active conformation of the LBD, enabling its crystallization. The resulting crystal structures provide a detailed picture of the ligand-binding pocket, allowing the design of highly specific synthetic ligands that can be used to characterize the function of orphan nuclear receptors. An additional advantage of this new method is that it is not based on a functional test and that it can detect low-affinity ligands. [source] Identification of an unusual naturally occurring apolar fatty acid amide in mammalian brain and a method for its quantitative determinationRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 3 2006Maurizio Dalle Carbonare Fatty acid amides (FAAs), such as the N -acylamides, N -acylethanolamides, N -acyldopamines and N -acylamino acids, are now emerging as an important new class of lipid-signalling molecules. This paper provides evidence, based on high-performance liquid chromatography/electrospray ionisation mass spectrometry (HPLC/ESI-MS/MS), gas chromatography/mass spectrometry (GC/MS) and 1H-NMR, of the occurrence in mouse and bovine brain extracts of a compound characterised by a mass spectrum attributable to a FAA not previously described, namely, the isopropyl-amide of stearic acid (SIPA). A highly sensitive GC/MS method was developed for quantification of naturally occurring SIPA and, also, for purposes of comparison, that of palmitoylethanolamide (PEA), a structurally related compound commonly determined in animal tissues. The results obtained show that SIPA levels in mouse brain are 8,10-fold higher than those of PEA. Moreover, SIPA was found in human neuroblastoma cell (SHSY-5Y) extracts, at significantly higher levels following exposure of the cells to the mitochondrial inhibitor rotenone. All this evidence not only shows surprisingly that SIPA may be found naturally in mammalian biological extracts despite the unusual functional group (i.e. isopropylamide) implicated, but also raises many important questions concerning its biological origin. Copyright © 2005 John Wiley & Sons, Ltd. [source] Cryotolerance of Bovine Blastocysts is Affected by Oocyte Maturation in Media Containing Palmitic or Stearic AcidREPRODUCTION IN DOMESTIC ANIMALS, Issue 1 2009MA Shehab-El-Deen Contents In this study, non-esterified fatty acids (NEFAs) were added during in vitro maturation at concentrations measured previously in follicular fluid (FF) of high-producing dairy cows in a negative energy status to evaluate their subsequent effect on the embryos cryotolerance. Oocytes were matured for 24 h in serum-free media with or without (negative control) the addition of NEFAs dissolved in ethanol or ethanol alone (positive control). Matured oocytes were fertilized and cultured for 7 days in synthetic oviduct fluid medium supplemented with 5% FCS. Embryos that had at least reached the blastocyst stage were vitrified by open pulled straw (OPS) vitrification. Addition of palmitic (C16 : 0) or stearic acid (C18 : 0) during oocyte maturation had significant negative effects on embryo cryotolerance, whereas ethanol or oleic acid (C18 : 1) had no effect. These in vitro results suggest that high NEFA concentrations in FF during a period of negative energy balance in high-yielding dairy cows can have carry-over effects on embryo quality. [source] | ||||||||||||||||||||||