bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of geranyl acetate by lipase entrap‐immobilized in cellulose acetate‐TiO2 gel fiber
Authors: Ikeda Yuko , Kurokawa Youichi
Published: November 2006

Lipase from Candida antarctica was entrap‐immobilized in cellulose acetate‐TiO2 gel fiber (fiber‐immobilized lipase) by the sol‐gel method. Syntheses of geranyl acetate and citronellyl acetate catalyzed by the fiber‐immobilized lipase were studied in heptane solution. Conversions reached 85% for geranyl acetate after 100 h, and 75% for citronellyl acetate after 80 h, and these values were almost identical to those for syntheses catalyzed by nonimmobilized lipase, although the reaction rate was decreased by immobilization. Compared to those of the non‐immobilized lipase and commercially available immobilized lipase (Novozyme 435), the activity of the fiber‐immobilized lipase was not particularly affected by changes in reaction conditions, such as bulk water content or substrate concentration. The fiber‐immobilized lipase retained a high level of activity after six repeated uses, and almost no enzyme leakage from fiber was observed. However, the reactivity of the fiber‐immobilized lipase was depressed at higher temperature, presumably due to dehydration by thermal contraction of the gel fiber.
Solvent‐based fatty alcohol synthesis using supercritical butane. Thermodynamic analysis
Authors: Brands D. S. , Poels E. K. , Dimian A. C. , Bliek A.
Published: November 2006

Conventional liquid‐phase fatty ester hydrogenolysis processes are necessarily operated at high pressures owing to the limited solubility of hydrogen in the reaction medium. In a solvent‐based process this problem can be overcome, but recycling and product‐solvent separation may turn out to be difficult. An alternative is the use of supercritical solvents, for which the solubility of fatty esters and fatty alcohols is high. Dropping the pressure into the subcritical domain allows for easy product separation and reactant recycle. In the present work we have analyzed the hydrogenolysis of methyl palmitate in supercritical butane. A reliable estimation of properties of the supercritical mixture can be obtained by fitting experimental vapor‐liquid equilibrium data with Schwatzentruber‐Renon cubic equation of state. The reaction mixture remains supercritical for a maximum pressure of 9 MPa and temperature of 470 K for mole fractions of hydrogen and methyl palmitate of 0.1 and 0.025, respectively. In these conditions an equilibrium conversion of more than 99% can be reached. An industrial process is feasible.
Distribution of chlorophylls and carotenoids in ripening olives and between oil and alperujo when processed using a two‐phase extraction system
Authors: Gallardo‐Guerrero Lourdes , Roca María , Isabel Mínguez‐Mosquera M
Published: November 2006

The present work has studied the content and type of pigments present in olive fruits and the respective oils and alperujos. The concentration of isochromic pigment fractions—chlorophylls and carotenoids—decreased with fruit ripening, more markedly in the former than in the latter. This implied that the ratio between the two pigment fractions also decreased in parallel in the three products studied. However, the value in the oil was lower than in the fruit, and that in the alperujo was much higher. During the extraction process, the release of acids may have caused pheophytinization reactions in the chlorophyll fraction, increasing pheophytin content in alperujos and oils, whereas the carotenoid fraction was affected only in the alperujo. Chlorophyll b derivatives were destroyed in greater proportion than chlorophyll a derivatives during transfer to the oil. During processing the destruction of lutein was greater than that of β‐carotene. The balance of matter between fruit, alperujo, and oil indicated that not all the fruit pigmentation was released from the structures, and most remained occluded in the alperujo. The rest of the pigmentation, and particularly the chlorophyll fraction, was partly destroyed during its transfer to the oil.
A novel approach to process crude oil membrane concentrate using a centrifuge
Authors: Gupta R. , Muralidhara H. S.
Published: November 2006

The present work discusses an alternative process to handle crude oil membrane concentrate during a degumming process. In this process, the membrane concentrate, which typically consists of 15–30% phospholipids (PL) by weight of oil, is first stripped of hexane and then centrifuged to produce two phases—supernatant (PL<0.6%) and lecithin concentrate (PL>62%). The main advantages of this method are limited oil loss, potential lecithin by‐product, and a supposedly simpler process. In this work, we first show that the phase behavior of an oil‐PL‐hexane system can be exploited to identify the various steps of the process. The steps include membrane degumming, hexane evaporation, and centrifugation. Although much knowledge already exists on these unit operations for miscella degumming, it is the combination and sequence of these steps that is proposed here. Since the novelty of this process lies in using a centrifuge after the membrane separations, we focus on this step. Here, we evaluate the dependence of hexane removal, moisture, temperature, hexane amount, residence time, centrifuge g‐force, and nonhydratable PL on the phase separations.
Low molecular weight polypeptides in virgin and refined olive oils
Authors: Hidalgo Francisco J. , Alaiz Manuel , Zamora Rosario
Published: November 2006

Twenty‐eight virgin olive oils—from different regions of Spain and prepared from olive drupes of different varieties—and six refined olive oils were analyzed to determine the presence of proteins in these oils. All oils studied showed the presence of proteins in the range of 7–51 μ/100 g of oil. There were no significant differences in protein content in oils from different varieties or between virgin or refined oils. In addition, all oils exhibited analogous amino acid patterns, suggesting a similarity among protein fractions obtained from different oils. A polypeptide with an apparent M.W. of 4600 Da was common to the isolated protein fractions. These results suggest that this polypeptide is a previously unknown minor component in olive oils. No clear influence of this component on oil stability was observed when oil stabilities were estimated as a function of phenol, tocopherol, phosphorus, and protein contents of the oils.
Low‐temperature flow properties of vegetable oil/cosolvent blend diesel fuels
Authors: Dunn R. O.
Published: November 2006

Vegetable oils are an attractive renewable source for alternative diesel fuels. However, the relatively high kinematic viscosity of vegetable oils must be reduced to make them more compatible with conventional compression‐ignition engines and fuel systems. Cosolvent blending is a low‐cost and easy‐to‐adapt technology that reduces viscosity by diluting the vegetable oil with a low‐M.W. alcohol (methanol or ethanol). The cosolvent (A), which consists of one or more amphiphilic compounds, is added to solubilize the otherwise nearly immiscible oil‐polar alcohol mixture. This work investigates cold flow properties and phase equilibrium behavior associated with blends consisting of soybean oil (SBO) and methanol where A=8∶1 (mol) n‐butanol/oleyl alcohol; 6∶1 (mol) 2‐octanol/triethylammonium linoleate; and 4∶1 (mol) 2‐octanol/Unadol 40 (alcohols from SBO FA); and a blend of 2∶1 (vol/vol) No. 2 diesel fuel/SBO and 95% ethanol where A=n‐butanol. Cloud point (CP), pour point, cold filter plugging point (CFPP), and low‐temperature flow test (LTFT) results were compared with corresponding phase separation temperature (Tϕ) data measured at equilibrium. Although CP data were measured under non‐equilibrium experimental conditions, a nearly linear correlation was found between Tϕ and CP. Statistical analysis showed that Tϕ may also be correlated with CFPP and LTFT. Analysis of heating and cooling DSC curves indicated that peak temperatures may be employed to predict cold flow properties and Tϕ behavior for SBO/cosolvent blends. Cooling curve parameters correlated more readily than heating curve parameters. Finally, relatively low quantities of heat evolved during freezing indicated that crystallization in the SBO/cosolvent blends studied in this work occurs easily during cooling.
Toluenesulfonate‐acyl esters of ethylene glycol and other 1,2‐diols as industrial antioxidants with cupric ion
Authors: Jiang Yongyi Julia , Hammond Earl G.
Published: November 2006

Ethylene glycol esters of soybean oil FA increased in viscosity much more slowly than methyl or glycerol esters when oxidized at 105°C in the presence of flowing air and colloidal copper. This increased stability was caused by a minor constituent of the ethylene glycol esters, which was shown by MS to be a mixed ethanediol fatty acylate p‐toluenesulfonate (EFAT). The p‐toluenesulfonate group came from the catalyst used in the formation of the ethylene glycol esters. EFAT was quantified by UV spectrometry, HPLC, or GC of the acyl group that it contains. EFAT could be synthesized in good yield by reacting ethylene glycol, a FA, and p‐toluenesulfonic acid (TSA) in a 1∶1∶1 molar ratio using a benzene azeotrope to remove water of esterification. EFAT increased the time required for the polymerization of soybean oil by about 27 times but required concentrations of 2–5% by weight. EFAT made with a variety of FA were active in delaying viscosity increase. Ethyl and decyl p‐toluenesulfonate were inactive. Replacing ethylene glycol by glycerol and 1,2‐propylene glycol but not by 1,3‐propylene glycol resulted in active EFAT. TSA itself delayed the polymerization of soybean oil, especially in the presence of free ethylene glycol and FA, but this probably was caused by formation of EFAT during the oxidation test. Colloidal copper could be replaced by cupric ion. EFAT‐copper appeared to act as an antioxidant by destroying hydroperoxides without initiation of free radical chains.
Fractionation of transgenic corn for recovery of recombinant enzymes
Authors: Yildirim S. , Fuentes R. G. , Evangelista R. , Nikoloy Z. L.
Published: November 2006

Two germ‐separation methods, dry‐milling and density separation by flotation, were evaluated for recovering recombinant β‐glucuronidase (rGUS) that accumulated primarily in the germ of transgenic corn. The dry‐milling process consisted of (i) seed tempering, (ii) degerming with a horizontal‐drum degermer/dehuller, (iii) particle size fractionation with standard sieves, (iv) germ and endosperm separation by roller milling and sifting, and (v) removal of hulls by aspiration. Sieves nos. 5, 6, and 7 retained the majority of germ, and subfractions from these sieves were pooled as a germ‐rich fraction. Mass balances showed that the germ‐rich fraction, which constituted 17% of the total dry‐milled corn weight, contained 49% of rGUS activity and 64% of the total recoverable oil. Germ fractionation by flotation was tested as a proof‐of‐concept method aimed at separating corn fractions based on their difference in specific gravity (sp gr). The process consisted of impact‐grinding of corn kernels followed by density separation using 1.15 or 1.3 specific gravity sodium nitrate solution. The oil‐containing germ fraction floated, whereas the heavier endosperm fraction sedimented. The flotation method was simpler and resulted in higher enzyme recovery, that is, the germ‐rich fraction was 20% (w/w) of the initial corn weight, and accounted for 80% of rGUS activity and 77% of total oil. The sodium nitrate solution did not have an adverse effect on the enzyme activity.
Adhesive qualities of soybean protein‐based foamed plywood glues
Authors: Hojilla‐Evangelista Milagros P.
Published: November 2006

The potential of soy protein‐based plywood glues for foam extrusion was evaluated. Standard glue mixes containing the soy flours Honeysoy 90, ISU‐CCUR, Nutrisoy 7B, and defatted Soyafluff, and the soy concentrates Arcon F and Procon 2000 showed excellent foaming and adhesive qualities but did not have the ability to refoam. To improve refoaming capability, the formulations were modified by increasing the quantities of soy flour or concentrate so that they provided 3.48 g protein/100 g of glue mix. This was the amount of protein contributed by animal blood when it was used as the extender in the standard formulation for foamed glue. All the modified glues containing soy flour or concentrate had good refoaming properties and adhesive strengths that were at least equal to that of the control glue. Simple cost analysis also indicated that when soy flour was used, the modified formulations were cheaper to produce than the current blood‐based glue.
Effect of emulsion temperature on physical properties of palm oil‐based margarine
Authors: Miskandar M. S. , Che Man Y. B. , Yusoff M. S. A. , Abdul Rahman R.
Published: November 2006

Margarines made from refined, bleached, and deodorized palm oil at different emulsion temperatures showed no significant difference in their consistency, polymorphic behavior, and solid fat content (SFC) during storage, although differences were observed during processing. The emulsion temperatures studied were 40, 45, and 50°C, with other parameters such as emulsion flow rates, tube cooler temperature, and pin rotor speed kept constant. The SFC developed during processing and storage at 28°C was measured to evaluate the quality of margarine. The emulsion contained no SFC at any emulsion temperature studied. However, the amount of SFC in the perfector or tube cooler unit increased to 15.9, 13.9, and 15.6% in margarine produced at emulsion temperatures of 40, 45, and 50°C, respectively. At 40°C, the lowest SFC was developed during storage even though this margarine had the highest consistency. The softening point of this sample was moderately high and closely related to the type of crystal developed, which was a mixture of β′ and β crystals. Emulsion at 45°C gave the most stable margarine consistency and SFC with crystal in the β′ form even after the fourth week. At 50°C, moderately soft product was produced, which might be undesirable for some applications, although the crystals were in the β′ form.
An improved method for determining the composition of FFA in red tide flagellates by RP‐HPLC with fluorescence detection
Authors: Terasaki Masaru , Itabashi Yutaka , Suzuki Toshiyuki , Nishimura Kazuhiko
Published: November 2006

An improved method for determining the composition of FFA in red tide flagellates by HPLC with fluorescence detection is described. For this purpose, total lipids from Heterosigma akashiwo, Chattonella antiqua, and C. marina were allowed to react with 9‐anthryldiazomethane, then the resulting 9‐anthrylmethyl esters of FFA were analyzed without any purification by RP‐HPLC on a highly efficient C18 column (Superspher 100 RP‐18e, 25 cm×4 mm i.d., 4 μm particle size; Merck, Darmstadt, Germany). Clear separations of long‐chain saturated and unsaturated FFA, including 14∶0 and 16∶1, which were major components in the flagellates and were unresolved on a previously used C18 column, were achieved by a stepwise gradient elution using acetonitrile, water, and propan‐2‐ol. Two characteristic FA, 18∶5n−3 and trans‐16∶1n−13, whose behaviors on RP‐HPLC had not been reported previously, were also clearly separated from the other FFA. The FFA compositions of the flagellates determined by HPLC were in good agreement with those obtained by GLC. The present method is simple and sensitive, and would be widely applicable for compositional analysis of microalgal FFA.
Two‐stage solvent extraction of seeds of Hibiscus abelmoschus linn: Lipid and FA compositions
Authors: Sahoo D. , Jena K. S. , Rout P. K. , Rao Y. R.
Published: November 2006

The lipid and FA compositions of TAG seed oil of ambrette (Hibiscus abelmoschus), contrary to earlier reports, were found to contain only a small amount of epoxy FA. Higher HBr absorption values were shown to be due to the presence of fragrance components of the seed coat in the oil derived from intact whole seeds. Cyclopropene/cyclopropane acids in the FAME were determined to be about 1.5% by GLC, while epoxy acids were less than 1% by two different methods. Based on the physicochemical characteristics and lipid and FA compositions of the fresh and methanol‐extracted seeds, ambrette TAG oil may be a candidate for edible use. The process of selective recovery of the expensive fragrant oily concentrate in higher yield in a first step and of an edible fatty oil in a second step makes it an attractive economic proposal.
Synthesis of 13(14)‐hydroxy‐cis‐10‐nonadecenyl amine hydrochloride
Authors: Balakrishnan S. , Raghavan D.
Published: November 2006

Compatibility between a hydrophilic nanoclay reinforcement and organophilic polymer matrix resin is achieved by ion exchange reaction substitution of intra gallery mono‐ or divalent cation with foreign aliphatic long‐chain cation. The exchange of long‐chain cation increases the organophilicity of the clay layers and provides sufficient layer separation for polymer chains to impregnate into the formation of a nanocomposite. This study demonstrates the synthesis of hydroxy functional longchain amine hydrochloride from Vernonia galamensis oil (VO). Vernonia galamensis oil, containing a naturally epoxidized long‐chain TG, was transesterified under basic conditions to yield VO methyl esters (VOMe). The VOMe were reduced using lithium aluminum hydride (LAH) in hexane to obtain cis‐12,13‐epoxy‐cis‐9‐octadecenol (vernanol) as the primary product. Vernanol was then converted to vernanyl mesylate, followed by reaction with potassium cyanide to obtain cis‐13,14‐epoxy‐cis‐10‐nonadecenitrile (C19 nitrile). The C19 nitrile was reduced with LAH in diethyl ether medium and later reacted with hydrochloric acid to obtain the title product. 1H and 13C NMR, FTIR, and matrixassisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) techniques were used to characterize the intermediates and the title product.
Use of rosemary extract in preventing oxidation during deep‐fat frying of potato chips
Authors: Lalas Stavros , Dourtoglou Vassilis
Published: November 2006

The effect of using a rosemary extract on the stability of oil used for frying potato chips has been evaluated. Sliced potatoes were fried intermittently in soybean oil containing a natural extract from rosemary. The conditions used for frying were 185°C for 90 s. Two separate experiments, with and without replenishment of oil, were carried out. Oil samples were taken each day, not only from the frying pans but also by extraction with hexane from the chips. Changes in the induction period of the oil samples (Rancimat method) were determined. The induction period decreased as frying progressed. The reduction in the induction period was higher in the oil free of rosemary extract, and the chips were much darker in color. The oil containing the extract showed greater antioxidant activity, and reduced darkening and rancidity of the oil. Potato chips fried in the oil with added rosemary extract were more acceptable than chips fried in oil containing no extract until the last frying. The free radical scavenging activity of rosemary extract in comparison to other natural antioxidants was also determined by the reduction of O2.‐ in a hypoxanthine/xanthine oxidase system.
An aqueous suspension system for phospholipase D‐mediated synthesis of PS without toxic organic solvent
Authors: Iwasaki Yugo , Mizumoto Yukiko , Okada Takahiro , Yamamoto Takaya , Tsutsumi Kentaro , Yamane Tsuneo
Published: November 2006

Enzymatic synthesis of PS by phospholipase D (PLD)‐mediated transphosphatidylation in an aqueous media was investigated. The purpose of this study was to establish a novel synthetic method where no toxic organic solvents were used. An attempt to react soybean lecithin (simply dispersed in an aqueous buffer) with an aqueous solution of l‐serine and PLD was unsuccessful, giving only 20% of PS. By contrast, a suspension of lecithin adsorbed on fine powders such as silica was effectively converted into PS in an aqueous solution of l‐serine and PLD. After screening various powders for use as the lecithin adsorbent, calcium sulfate was found to be the best with respect to lecithin conversion. In addition, calcium sulfate did not require prior adsorption of lecithin (i.e., the reaction proceeded effectively simply by adding the powder to an aqueous mixture of lecithin, l‐serine, and PLD). With this “aqueous suspension system” of calcium sulfate, up to 180 mg/mL lecithin was completely converted, resulting in more than 80% PS in 24 h. The synthesized PS could easily be recovered from the powder by extracting with a mixture of n‐hexane, ethanol, and diluted HCl.
Oxidation kinetics for cis‐9,trans‐11 and trans‐10,cis‐12 isomers of CLA
Authors: Minemoto Yasumasa , Adachi Shuji , Shimada Yuji , Nagao Toshihiro , Iwata Toshio , Yamauchi‐Sato Yoshie , Yamamoto Takaya , Kometani Tadashi , Matsuno Ryuichi
Published: November 2006

The autoxidation processes of the cis‐9,trans‐11 (c9,t11) and trans‐10,cis‐12 (t10,c12) isomers of CLA were separately observed at ca. 0% RH and different temperatures. The t10,c12 CLA oxidized faster than the c9,t11 isomer at all tested temperatures. The first half of the oxidation process of t10,c12 CLA obeyed an autocatalytic‐type rate expression, but the latter half followed first‐order kinetics. On the other hand, the entire oxidation process of c9,t11 CLA could be expressed by the autocatalytic‐type rate expression. The apparent activation energies and frequency factors for the autoxidation of the isomers were estimated from the rate constants obtained at various temperatures based on the Arrhenius equation. The apparent activation energies for the CLA isomers were greater than those for the nonconjugated n−6 and n−3 PUFA or their esters. However, the enthalpyentropy compensation held during the autoxidation of both the CLA and PUFA. This suggested that the autoxidation mechanisms for the CLA and PUFA were essentially the same.
Natural estolides produced by Pseudomonas sp. 42A2 grown on oleic acid: Production and characterization
Authors: Peláez M. , Orellana C. , Marqués A. , Busquets M. , Guerrero A. , Manresa A.
Published: November 2006

Estolides are a group of FA polyesters resulting from ester bond formation between a hydroxyl or olefinic group of one FA and the terminal carboxyl group of a second FA. These products are commonly found in trace amounts, forming tetraglycerides in several oil seed plants, and have been produced by acid clay and enzymatic catalysis in vitro. In this study, natural estolides produced by a bacterial culture are presented for the first time. Pseudomonas sp. 42A2 produced (E)‐10‐hydroxy‐8‐octadecenoic acid and (E)‐7,10‐dihydroxy‐8‐octadecenoic acid when grown on oleic acid. It is suggested that these FA were polymerized in culture by a lipase produced by the bacterial strain, resulting in a mixture of estolides. These compounds amounted to 3.8 g/L after 72 h of incubation. LC‐MS analysis indicated that the types of estolides formed were dimers (m/z 560–610), trimers (m/z 845–906), tetramers (m/z 1122–1202), pentamers (m/z 1328–1424), and hexamers (m/z 1554–1788), with a relative abundance of 27.5, 19.4, 15, 9.7, and 11%, respectively. This is the first report in which hexamers were detected in a bacterial culture.
Continuous production of acyl l‐ascorbates using a packed‐bed reactor with immobilized lipase
Authors: Kuwabara Ko , Watanabe Yoshiyuki , Adachi Shuji , Nakanishi Kazuhiro , Matsuno Ryuichi
Published: November 2006

Saturated acyl (6‐O‐caproyl, lauroyl, and myristoyl) and unsaturated acyl (6‐O‐oleoyl, linoleoyl, and arachidonoyl) l‐ascorbates were continuously synthesized at 50°C using a system where a column packed with ascorbic acid powder and a packed‐bed reactor with an immobilized lipase from Candida antarctica were connected in series. A productivity of 1.6–1.9 kg/L reactor·d was achieved for at least 11 d. The surface tension of the caproyl or lauroyl l‐ascorbate in aqueous solution was measured at various temperatures and pH to estimate the critical micelle concentration (CMC) of the acyl l‐ascorbate. The CMC values were independent of temperature but dependent on the pH. The value of the caproyl ascorbate increased with an increase in pH.
Pressurized liquid extraction of polar and nonpolar lipids in corn and oats with hexane, methylene chloride, isopropanol, and ethanol
Authors: Moreau Robert A. , Powell Michael J. , Singh Vijay
Published: November 2006

Samples of freshly ground corn kernels and freshly ground rolled oats were extracted via pressurized liquid extraction (accelerated solvent extraction) using four different organic solvents [hexane, methylene chloride (also known as dichloromethane), isopropanol, and ethanol] at two temperatures (40 and 100°C). Lipid yields varied from 2.9 to 5.9 wt% for ground corn and from 5.5 to 6.7 wt% for ground oats. With ground corn, more lipid was extracted as solvent polarity was increased, and for each individual solvent, more lipid was extracted at 100°C than at 40°C. With ground oats, the same temperature effects was observed, but the solvent polarity effect was more complex. For both corn and oats, methylene chloride extracted the highest levels of each of the nonpolar lipid classes. In general, for both corn and oats, icnreasing solvent polarity resulted in increasing yields of polar lipids, and for each solvent, more of each lipid class was extracted at 100°C, than at 40°C. Among the lipids in corn extracts, the phytosterols may be the most valuable, and total phytosterols ranged from about 0.6 wt% in the hot ethanol extracts to about 2.1 wt% in the hot hexane and methylene chloride extracts. Total phytosterols in all oat extracts were about 0.1 wt%. Digalactosyldiacylglycerol was the most abundant polar lipid in the oat extracts; its levels ranged from 1.6 wt% in the cold hexane extracts to 4.3 wt% in the hot ethanol extracts.
Effect of triacylglycerol structures on the thermal oxidative stability of edible oil
Authors: Hoshina Ryosuke , Endo Yasushi , Fujimoto Kenshiro
Published: November 2006

Different molecular species of TAG were assessed to determine the influence of TAG structure on the thermal oxidative stability of edible oil. TAG containing palmitic acid (16∶0, P) as saturated FA (SFA) and oleic acid (18∶1, O), linoleic acid (18∶2, L), or linolenic acid (18∶3, Ln) as unsaturated FA (UFA) were chemically synthesized and then heated at 180 or 150°C. Thermal oxidative stability of TAG was determined by evaluating the resultant UFA, polar compound, FFA, carbonyl compound, polymerized compound, and tocopherol contents. When TAG containing 16∶0 and 18∶2 in the ratio of 2∶1 (mol/mol) were heated at 180°C, a 2∶1 (mol/mol) mixture of saturated TAG (PPP) and unsaturated TAG (LLL) was found to be more susceptible to thermal oxidation than PPP/PLL (1∶1) and PPL. Similarly, a 2∶1 mixture of PPP and OOO or LnLnLn was more unstable toward thermal oxidation than PPO or PPLn, respectively. Thermal oxidative stability of TAG containing SFA and UFA (2∶1) was negatively correlated with the moles of UFA in a single TAG molecule. This tendency was also observed at 150°C. From these results, it is suggested that the TAG structure could be one of the factors determining the thermal oxidative stability of edible oil.
Dehydration of glycerin/water mixtures by pervaporation using homo and copolymer membranes
Authors: Khairnar D. B. , Pangarkar V. G.
Published: November 2006

Separation characteristics of glycerol/water mixtures were studied using hydrophilic poly(acrylonitrile‐comethacrylic acid) (PANMAC), poly(acrylonitrile‐co‐hydroxyethyl methacrylate) (PANHEMA), Poly(vinyl alcohol) GFT‐1001, and poly(vinyl alcohol) (PVA) crosslinked with maleic anhydride (PVAManh) membranes. All membranes were found to be highly water selective. PVAManh membrane yielded the highest permeation flux for water over the entire range of water concentration studied. Homopolymers (PVAManh and GFT‐1001) gave better permeation rates than copolymer membranes (PANHEMA and PANMAC). But the swelling of homopolymers is nuch greater than that of copolymers, which is why PVA membranes have poor longevity. No effect on selectivity of the membrane was observed with a change in operating parameters. No decomposition/polymerization of glycerin was observed, as there was no involvement of high temperatures as there is with distillation. A comparison of pervaporation with vapor‐liquid equilibrium data showed that pervaporation of glycerin/water mixtures yielded better selectivity than vapor‐liquid equilibrium, particularly for glycerol concentrations above 90 wt%.
Prediction of crude sunflower oil deterioration after seed drying and storage processes
Authors: Bax M. M. , Gely M. C. , Santalla E. M.
Published: November 2006

The effects of air‐drying temperature and storage time on several characteristics of crude sunflower oil were evaluated in terms of FFA and PV. Long storage affected oil content to a greater extent than air‐drying temperature. FFA and PV varied between 0.53 and 1.22% and between 10.7 and 23.3. meq O2/kg, respectively, when samples of uniform initial moisture content (approximately 28%) were dried at various temperatures between 25 and 90°C to approximately 7% moisture content, stored for 8 mon, and then analyzed. Both oil quality characteristics increased exponentially with air‐drying temperature (T) and linearly with storage time (t). Mathematical functions of the form A·exp(B·T)+C·t (where A, B, and C are parameters adjusted from experimental data) most closely predicted the experimental loss of quality of sunflower oil in terms of FFA and PV with variations in T and t. Statistical analysis showed SE of the estimated parameters of 0.08 and 1.19 and coefficients of determination, R2, of 0.922 and 0.939 for FFA and PV, respectively, which were significant at 95% confidence. High‐oleic seeds from a similar experiment were used to validate the proposed equation. The results of applying the mathematical function proposed above showed a reasonable ability to predict the experimental values with SE of 0.037 and 0.808 and R2 of 0.983 and 0.972 for FFA and PV, respectively, which were significant at 95% confidence. Plots of residuals showed random distribution. The results obtained suggested that the equation proposed could be used as a quality‐loss model in sunflower drying simulations.
The constant variation: DNA methylation changes during preimplantation development
Authors: Arányi Tamás , Páldi András
Published: November 2006

Studies on the DNA methylation changes in the mouse preimplantation embryo suggested a simple and attractive model explaining the process believed to be general in mammals. However, recent reports revealed marked differences between different species that abrogates the universal validity of the model. In order to find an explanation to the differences, we have analyzed the published mouse data and compared them to the observations available in other species. The emerging common theme is the high variability of the methylation at all scales of observation and all levels of organization. This variability is the likely consequence of a dynamic and active redistribution process of the cytosine methylation in the genome.
Theoretical study of the pre-ionized XeCl laser
Authors: HARRACHE Z. , BELASRI A.
Published: November 2006

In this paper, we use numerical modeling to study some characteristics of the XeCl laser under homogeneous pre-ionization conditions. The study is executed using a model combining external circuit and plasma kinetics. The model validity is checked by comparing the model results to the experimental data from the literature. A qualitative agreement was found.
Biology of the schistosome lung-stage schistosomulum
Authors: GOBERT G. N. , CHAI M. , McMANUS D. P.
Published: November 2006

Past and more recent research has examined the ultrastructure, metabolism, cell biology, genomics and post-genomics of schistosome schistosomula. These areas are considered and discussed in this review with particular emphasis on (1) the early migration phases through the host, (2) interaction of the host immune response with the parasite surface, (3) glucose uptake mechanisms, and (4) defining the transcriptional profiles of lung-stage schistosomula compared with other developmental stages using microarrays. The microarray profiling studies suggest caution is required when considering the use of schistosomes obtained byin vitromeans for molecular or biochemical studies.
Rotavirus VP7, VP4 and VP6 genotypes co-circulating in Tehran, Iran, between 2003 and 2004
Authors: FARAHTAJ F. , GALLIMORE C. I. , ITURRIZA-GOMARA M. , TAREMI M. , ZALI M. R. , EDALATKHAH H. , FAYAZ A. , GRAY J. J.
Published: November 2006

Rotaviruses were detected by enzyme-linked immunosorbent assay (ELISA) in 92 out of 374 faecal samples collected between November 2003 and October 2004 at the Markaz Tebbi Koudakan Hospital, Tehran, Iran, from children aged 6 months to 5 years. Analysis of clinical and disease severity data showed a significant association between rotavirus infection and diarrhoea, vomiting and severe dehydration. Ninety-two samples (64 rotavirus ELISA-positive and 28 ELISA-negative samples) were sent to the Enteric Virus Unit, Virus Reference Department, Centre for Infection, Health Protection Agency, UK for rotavirus characterization by G-typing, P-typing and subgrouping (SG) using reverse transcriptase (RT)–PCR, semi-nested PCR and sequencing methods. In this study, both common and uncommon rotavirus genotypes were detected. The most prevalent types were G1P[8], SGII (59·2%) followed by G9P[8] SGII (15·5%) which has not been previously reported from Iran. Unusual genotypes G1P[10] SGI (2·8%) and G12P[8] SGII (1·4%) and strains derived from reassortment between common co-circulating genotypes such as G1P[4] SGII represented 5·6% of strains. Mixed infections with combinations of G1+G4P[8] SGII and G1+G9P[8] SGII were also found. This contrasts with previous reports from Iran in which a small number of common rotavirus strains (G1 and G4) were found. This study highlights the need for continued surveillance and characterization of rotaviruses to take account of the rapid evolution and introduction of novel rotaviruses into the human population.
More than one variant ofListeria monocytogenesisolated from each of two human cases of invasive listeriosis
Authors: THAM W. , VALLADARES G. LOPEZ , HELMERSSON S. , ÖSTERLUND A. , DANIELSSON-THAM M.-L.
Published: November 2006

Two variants ofListeria monocytogeneswere isolated from blood cultures from each of two patients with listeriosis. Each variant displayed a two-band difference in DNA profile from the other by pulsed-field gel electrophoresis. Although this difference in profile is insufficient to distinguish clearly between the variants, the possibility of co-infection with different strains ofL. monocytogenesneeds to be considered. We suggest that more than one colony should be selected for molecular typing to aid interpretation during investigation of the sources and routes ofListeriainfection.
Low genetic diversity of the intrinsic OXA-51-like class D carbapenemases amongAcinetobacter baumanniiclinical isolates in Greece
Authors: IKONOMIDIS A. , POURNARAS S. , MARKOGIANNAKIS A. , MANIATIS A. N. , MANOLIS E. N. , TSAKRIS A.
Published: November 2006

This study examined the geographical distribution and diversity of the intrinsic OXA-51-like class D carbapenemases amongAcinetobacter baumanniiclones recovered in three major Greek regions from 2000 to 2005. TheblaOXA-66allele was exclusively detected among clonally distinctA. baumanniiisolates recovered in the regions of Thessaloniki and Larissa. This sequence was also the most widespread amongA. baumanniiisolates in Athens, while less frequent wereblaOXA-69andblaOXA-65alleles. These findings highlight the high prevalence of a specificblaOXA-51-likeallele in Greece, possibly indicating that ourA. baumanniiclones might have originated from a common ancestor. However, the possibility thatblaOXA-51-likevariants, withblaOXA-66predominating, are widely disseminated among several unrelatedA. baumanniistrains cannot be excluded.
Total antioxidant capacity of plasma in asymptomatic carrier state ofNeisseria meningitidis
Authors: UBEROS J. , MOLINA-CARBALLO A. , GALDO-MUÑOZ G. , MUÑOZ-HOYOS A.
Published: November 2006

Reduction of the antioxidant capacity of plasma has been linked with the impairment of an effective immune response and so we hypothesized that the carriage rate ofNeisseria meningitidisin asymptomatic subjects might correlate with the levels of antioxidants in plasma. To this end we took pharyngeal swabs from 339 children in Marquesado Basic Health Zone, Granada, Spain and in addition determined the total antioxidant capacity (TAC) in plasma samples from these subjects. The overall prevalence ofN. meningitidiscarriage was 5·9% (mean age 7·1 years) with rates of 10·3% in children aged ⩽3 years, 3·9% between 4 and 7 years and 2·4% in older subjects. Plasma TAC for the ⩽3-year-olds was 0·13 for carriers and 1·10 for non-carrier controls (P=0·04), 0·13 for carriers aged 4–7 years (controls 0·63) and 0·28 for carriers aged >7 years (controls 0·52). We analysed the association between TAC in plasma (<0·37 – 2s.d.) and the carrier state ofN. meningitidis. In the carrier state, the odds ratio for this association (TAC in plasma <0·25) was 8·44 (95% CI 1·5–48·9). These findings may suggest a reduced immune response in the host favourable to nasopharyngeal persistence of meningococci.
A note on ‘the simple analytics of the Environmental Kuznets Curve’
Authors: PLASSMANN FLORENZ , KHANNA NEHA
Published: November 2006

In a widely cited paper, Andreoni and Levinson (2001) argue that, under very mild restrictions on preferences, increasing returns to scale in pollution abatement are a sufficient condition for pollution to ultimately fall to zero with income growth. We show that the existence of an Environmental Kuznets Curve depends on the relative magnitudes of the returns to scale in abatement and in gross pollution, rather than on their absolute values. Increasing returns to scale in abatement by themselves are not sufficient for pollution to fall with income unless the returns to scale of abatement exceed the returns to the production of gross pollution.
Developing a rhythmic performance practice in music for piano and tape
Authors: DING SHIAU-UEN
Published: November 2006

There are many excellent works for piano and tape; however, there have been an insufficient number of pianists widely performing these works. The purpose of this article is to critically analyse the rhythmic relationships between piano and tape, serving a pedagogical function for both composers and pianists in technical and aesthetic terms. Hopefully these techniques will encourage pianists to include music for piano and tape as part of their repertoire.
A comparative evaluation of auditory-visual mappings for sound visualisation
Authors: GIANNAKIS KOSTAS
Published: November 2006

The significant role of visual communication in modern computer applications is indisputable. In the case of music, various attempts have been made from time to time to translate non-visual ideas into visual codes (see Walters 1997 for a collection of graphic scores from the late computer music pioneer Iannis Xenakis, John Cage, Karlheinz Stockhausen, and others). In computer music research, most current sound design tools allow the direct manipulation of visual representations of sound such as time-domain and frequency-domain representations, with the most notable examples being the UPIC system (Xenakis 1992), Phonogramme (Lesbros 1996), Lemur (Fitz and Haken 1997), and MetaSynth (Wenger 1998), among others. Associations between auditory and visual dimensions have also been extensively studied in other scientific domains such as visual perception and cognitive psychology, as well as inspired new forms of artistic expression (see, for example, Wells 1980; Goldberg and Schrack 1986; Whitney 1991).
Residual mean transport in the stratosphere: Contributions from wave driving and seasonal transience
Authors: Salby Murry L. , Callaghan Patrick F.
Published: November 2006

A three‐dimensional model of dynamics and photochemistry is used to evaluate the contributions to residual mean motion and ozone transport from planetary wave drag, gravity wave drag and from the seasonal transience of diabatic cooling. The integrations reveal that over much of the winter hemisphere, seasonal transience plays a major role in driving residual mean motion. During autumn, when the seasonal drift of radiative equilibrium temperature is fast, that contribution dominates. Following solstice, the dominant contribution to residual mean motion swings to wave driving. Similar dependence is reflected in the wintertime increase of total ozone and in the transfer of stratospheric ozone to the troposphere. Owing to the substantial contribution from seasonal transience, only about half of the net wintertime increase of Northern Hemisphere ozone (spring‐autumn) is actually available to change through changes of wave driving. Observed changes then represent nearly all of the wintertime increase that is available to change.
Atmospheric mercury chemistry: Sensitivity of global model simulations to chemical reactions
Authors: Seigneur Christian , Vijayaraghavan Krish , Lohman Kristen
Published: November 2006

The effect of new mercury (Hg) chemistry information on Hg atmospheric concentrations is investigated in a systematic manner with a global chemical transport model, taking into account current uncertainties in Hg emission and removal rates. The reactions of interest include the gas‐phase oxidation of Hg(0) by O3, the gas‐phase oxidation of Hg(0) by OH, the aqueous‐phase reduction of Hg(II) by HO2 radicals, a hypothetical gas‐phase reduction of Hg(II) by SO2, and a hypothetical pseudo‐first‐order gas‐phase reduction of Hg(II). The new kinetics of the oxidation of Hg(0) by O3 is fast and would require balancing by a commensurate reduction reaction pathway that has not been identified; it may include some heterogeneous component and should be seen as an upper limit for atmospheric applications. Eliminating the gas‐phase oxidation of Hg(0) by both O3 and OH does not lead to realistic Hg(0) concentrations even after eliminating the aqueous‐phase reduction of Hg(II) by HO2 and having a greater dry deposition rate of Hg(0). Thus gas‐phase oxidation of Hg(0) by oxidants such as O3 and/or OH is required to reproduce global Hg(0) concentration patterns. The reduction of Hg(II) by HO2 (or a reaction with a similar overall rate) is needed to balance the oxidation of Hg(0) by OH and O3 but is not needed if the gas‐phase oxidation of Hg(0) by OH is eliminated. The reduction of Hg(II) in power plant plumes can be represented by a reaction of Hg(II) with SO2; such a reaction is consistent with the global cycling of Hg. However, a first‐order reaction for Hg(II) reduction in power plant plumes is not consistent with our current understanding of the atmospheric Hg chemistry. Additional laboratory studies are recommended to address the remaining uncertainties in the atmospheric chemistry of Hg.
Carbon monoxide: A quantitative tracer for fossil fuel CO2?
Authors: Gamnitzer Ulrike , Karstens Ute , Kromer Bernd , Neubert Rolf E. M. , Meijer Harro A. J. , Schroeder Hartwig , Levin Ingeborg
Published: November 2006

Carbon monoxide (CO), carbon dioxide (CO2), and radiocarbon (14CO2) measurements have been made in Heidelberg from 2001 to 2004 in order to determine the regional fossil fuel CO2 component and to investigate the application of CO as a quantitative tracer for fossil fuel CO2 (CO2(foss)). The observations were compared with model estimates simulated with the regional transport model REMO at 0.5° × 0.5° resolution in Europe for 2002. These estimates are based on two available emissions inventories for CO and CO2(foss) and simplified atmospheric chemistry of CO. Both emissions inventories appear to overestimate fossil fuel emissions in the Heidelberg catchment area, in particular in summer and autumn by up to a factor of 2. Nevertheless, during meteorological conditions with high local source influence the CO/CO2(foss) emission ratios compared well with the observed atmospheric CO/CO2(foss) ratios. For a larger catchment area of several 100 km the observed CO/CO2(foss) ratio compared within better than 25% with the ratios derived from model simulations that take the transport from the sites of emission to the measurement station into account. Non‐fossil‐fuel CO emissions, production by volatile organic compounds, and oxidation, as well as soil uptake, turned out to add significant uncertainty to the application of CO as a quantitative fossil fuel CO2 surrogate tracer, so that 14CO2 measurements seem to be indispensable for reliable estimates of fossil fuel CO2 over the European continent.
Change of cloud amount and the climate warming on the Tibetan Plateau
Authors: Duan Anmin , Wu Guoxiong
Published: November 2006

Based on the 6‐hourly weather observations at 71 stations across the central and eastern Tibetan Plateau (TP) during 1961–2003, the change of cloud amount and its possible connection with recent climate warming on TP were investigated. The low‐level cloud amount exhibits a significant increasing trend during the nighttimes, leading to the enhanced atmospheric counterradiation, weakened effective terrestrial radiation, and the subsequently strong nocturnal surface warming. On the other hand, both the total and low‐level cloud amounts during daytime display decreasing trends, resulting in more absorbing of direct solar radiation at the surface and the associated surface warming. Since the increase in nocturnal low‐level cloud is more than the decrease of daytime low and total cloud amounts, such changes in cloud amount contribute to at least partly of the increased surface air temperature and its diminished diurnal range on TP.
Sound velocities of ferropericlase in the Earth's lower mantle
Authors: Lin Jung‐Fu , Jacobsen Steven D. , Sturhahn Wolfgang , Jackson Jennifer M. , Zhao Jiyong , Yoo Choong‐Shik
Published: November 2006

Sound velocity measurements on candidate mantle minerals at relevant mantle conditions are needed to interpret Earth's seismic structure in terms of model abundances, variable composition, and other potentially influential parameters such as electronic spin‐pairing transitions. Here the sound velocities of the lower‐mantle ferropericlase have been measured by nuclear resonant inelastic X‐ray scattering to 110 GPa. Compressional and shear wave velocities and their pressure derivatives rise dramatically across the spin‐pairing transition of iron in (Mg0.75Fe0.25)O above 50 GPa. Effects of the transition on the sound velocities of (Mg, Fe)O at lower‐mantle pressures yield values that are much greater than what is predicted by studying pure MgO and high‐spin ferropericlase. Our results indicate that sound velocities of the low‐spin ferropericlase need to be considered in future geophysical and geochemical models, which could offset the effect of the addition of iron in the lower‐mantle minerals and affect the evaluation of the lower‐mantle heterogeneities.