bluuebunny/crossref_metadata_2025_split huggingface dataset:
High pressure studies of mid‐infrared type‐II “W” diode lasers at cryogenic temperatures
Authors: O'Brien K. , Adams A. R. , Sweeney S. J. , Jin S. R. , Ahmad C. N. , Murdin B. N. , Canedy C. L. , Vurgaftman I. , Meyer J. R. 
Published: December 2006

AbstractUsing high hydrostatic pressure and spontaneous emission characterisation techniques we have investigated the important loss processes in type‐II “W” diode lasers, which emit at 3.24 μm at 78 K. Our studies indicate that Auger recombination involving the excitation of holes in the valence band and/or inter‐valence‐band absorption may contribute to the temperature sensitivity of these devices, even at cryogenic temperatures. Defect/impurity related recombination, which was of concern in these structures does not appear to make a significant contribution to the threshold current over the temperature and pressure ranges investigated. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Multiple linear regression with some correlated errors: Classical and robust methods
Authors: Pires Ana M. , Rodrigues Isabel M. 
Published: December 2006

AbstractIn this paper we consider classical and robust methods of estimation and diagnostics for the multiple linear regression model when some of the errors are correlated. This work was motivated by the analysis of a medical data set, from an observational study aimed at identifying factors affecting the outcome of a surgical method for the correction of scoliosis (abnormal lateral spinal curvature). There are 392 observations but some of them are on the same patient (double curves). It seems adequate to consider a multiple linear regression model but, since it is not desirable to discard the double curves, the assumption of non‐correlated errors is clearly violated, and this is indeed confirmed by related diagnostics on the residuals (Durbin–Watson test). A more appropriate model retains the linear structure but allows for non‐null correlation between the errors on the same patient. We propose two different procedures for the estimation of the parameters of the linear model and the correlation parameters: maximum likelihood assuming normal errors and a robustified version obtained by plugging‐in results from robust linear regression. The latter procedure is designed to be resistant to outlying observations or error distributions with heavy tails and has produced the most satisfactory results for the analysed data set. Copyright © 2006 John Wiley & Sons, Ltd.
The catalytic activity of lipases toward hydroxy fatty acids—A review
Authors: Hayes Douglas G. 
Published: December 2006

AbstractHydroxy fatty acids, derived from several natural and synthetic sources, have many applications. Lipases have been employed to catalyze reactions involving hydroxy acids to narrowly shape the product distribution via their regio‐ and stereoselectivities. This manuscript reviews the action of lipase on hydroxy acids and their derivatives. The formation of estolides or lactones by lipase‐catalyzed reactions depends strongly on the position of the hydroxyl moiety on the hydroxy acyl group and slightly on the hydroxy acid chainlength and concentration.Pseudomonas sp. and porcine pancreatic lipases are the most useful for catalyzing formation of optically pure lactones, while lipases lacking positional selectivity catalyzed estolide formation best. The product distribution of lipase‐catalyzed esterification between hydroxy‐ and nonhydroxy‐acyl groups is strongly dependent on the lipase type. Lipase‐catalyzed reactions between hydroxy acids and alcohols yield hydroxy esters, not estolides, as the major product.
Structure determination of long‐chain polyunsaturated triacylgyycerols by high‐resolution13C nuclear magnetic resonance
Authors: Bergana Marti M. , Lee Theresa W. 
Published: December 2006

AbstractThe application of13C nuclear magnetic resonance to determine the positional distribution of fatty acids on the glycerol backbone has been investigated. A systematic approach and synthetic triacylglycerols were used to measure the effect on the carbonyl chemical shifts of triacylglycerols by the positional distribution on the glycerol backbone and the number and position of the double bonds within the fatty acids. The correlation of13C carbonyl chemical shift to the molecular structure of triacylglycerol was delineated. The assignments for the chemical shifts of the carbonyl nuclei of monoacyltriacylglycerol standards were compiled. The resonance from the carbonyl carbons at the 1,3 positions is resolved from that at the 2 position. The13C carbonyl chemical shift was more dependent on the position of the double bonds than the degree of unsaturation of the fatty acids. In particular, little effect was observed in the chemical shifts for fatty acids containing more than two double bonds. However, the chemical shifts were influenced significantly by the position of the first double bond. The difference in the chemical shift of the unsaturated species from that of the saturated species was plotted against the position of the first double bond. A natural logarithmic relationship was found between carbon numbers 5 and 11. Inflection points were found outside of this region at carbon numbers 4 and 13. In addition, the resonances from the saturated species, independent of their chainlength, were degenerate in oil systems, even though small differences were observed in the standards. The applicability of this method was demonstrated in the determination of the composition and positional distribution of the fatty acids in borage and evening primrose oils.
Identification of α‐parinaric acid in the seed oil ofSebastiana brasiliensis sprengel (Euphorbiaceae)
Authors: Spitzer Volker , Tomberg Werner , Zucolotto Mônica 
Published: December 2006

AbstractBesides some usual fatty acids, the seed oil ofSabastiana brasiliensis (Euphorbiaceae) contains up to 39% (estimated by ultraviolet spectroscopy) of α‐parinaric acid (cis, trans, trans, cis‐9, 11, 13, 15‐octadecatetraenoic acid). The fatty acids were analyzed by gas chromatography and gas chromatography/mass spectrometry as their methyl esters. The structure of α‐parinaric acid was proven by a combination of chemical and spectroscopic methods, conducted with the crude oil, the methyl ester mixture, and the isolated fatty acid methyl ester. Complete assignment of the1H and13C nuclear magnetic resonance (NMR) shifts of α‐parinaric acid was carried out by two‐dimensional NMR experiments
Effect of genetic modification on the content and composition of bioactive constituents in soybean oil
Authors: Mounts T. L. , Abidi S. L. , Rennick K. A. 
Published: December 2006

AbstractThe content and composition of tocopherols, sterols, and phospholipids in soybean oils derived from genetically‐modified soybeans were determined by normal and reverse‐phase high‐performance liquid chromatography and gas‐liquid chromatography. Tocopherol content was lowered in oils from soybeans selected to yield high palmitate and stearate contents. However, β‐tocopherol, which amounts to less than 1 ppm in control oils, was increased to 25–53 ppm in these oils. Sterol content was higher in one reduced‐linolenate oil, which also had the highest oleate content. The greatest variability was observed in the content of β‐sitosterol, which ranged from 46.9–151.6 mg/100/g in the modified oils. Although, in general, there was little impact on the phospholipids, the content of phosphatidic acid was elevated in crude oils from three of the lines. Increases in phosphatidic acid are generally associated with storage deterioration of soybeans. Individual major classes of phospholipid were isolated, and the molecular species composition of each was determined. Compositional variations in molecular species indicated that there was an impact of the genetic modification of soybeans at the molecular level of the phospholipids that are primary plant cell components.
Immobilized lipase‐catalyzed production of structured lipids with eicosapentaenoic acid at specific positions
Authors: Lee Ki‐Teak , Akoh Casimir C. 
Published: December 2006

AbstractStructured lipids (SL) were synthesized by the interesterification reaction between medium‐chain triacylglycerols and eicosapentaenoic acid (EPA) ethyl ester. The products were partially purified, and the fatty acid at thesn‐2 position was determined after pancreatic lipase‐catalyzed hydrolysis. The effect of additives (water and glycerol) on the rate of reaction was also investigated. Mol% EPA incorporated into the triacylglycerols was increased by adding water when trilaurin and tricaprylin were the substrates and IM 60 was the biocatalyst. With SP 435, EPA incorporation was always less with additional water than without water. The addition of glycerol (0.005 g or 0.01 g) improved interesterification catalyzed by IM 60 to some degree, but an excess amount (0.02 g) inhibited the reaction. The reaction with glycerol showed no significant difference with SP 435. After scale‐up and fractionation by column chromatography, we could recover approximately 0.3–0.4 g of product/g of reaction products. After hydrolysis by pancreatic lipase, we can conclude that IM 60 has a high specificity forsn‐1,3 positions. With SP 435 lipase, 34.8–39.3 mol% of EPA was found at thesn‐2 position of the recovered SL.
Kinetic evaluation of 3β‐hydroxycholest‐5‐en‐7‐one (7‐ketocholesterol) stability during saponification
Authors: Park Peter W. , Guardiola Francesc , Park Susan H. , Addis Paul B. 
Published: December 2006

AbstractTo clarify conflicting information regarding 7‐ketocholesterol (7‐KC) recovery from saponification, we evaluated the stability of 7‐KC in methanolic alkaline medium. We added 1 N alcoholic KOH to 7‐KC or lard spiked with 7‐KC and held the mixtures at 45, 55, 65, and 75°C for different times to simulate various saponification conditions. Gas‐chromatographic determination of residual 7‐KC with 5α‐cholestane as the internal standard (IS) showed that the higher the saponification temperature, the greater the 7‐KC degradation. Hot saponification at 75°C for 30 min caused extensive destruction and left only 31% 7‐KC. 7‐KC loss during saponification could be described by pseudo first‐order kinetics, and the dependence of degradation rate on temperature (T, K) byk (h−1)=(2.6×1017) exp (−1.36×104/T). As predicted by the kinetic equation, 7‐KC loss during room‐temperature saponification (21°C) was practically negligible; following the exposure of 7‐KC or lard spiked with 7‐KC to 1 N alcoholic KOH for 18 h, about 97% 7‐KC was recovered. 6‐Ketocholestanol, when used as an IS, should be looked at carefully because of potential tautomerization, leading to the formation of two enol isomers when in extended contact with trimethylsilyl derivatization reagents.
Reducing the crystallization temperature of biodiesel by winterizing methyl soyate
Authors: Lee Inmok , Johnson Lawrence A. , Hammond Earl G. 
Published: December 2006

AbstractMethyl soyate, made from typical soybean varieties, has a crystallization onset temperature (Tco) of 3.7°C and, as a biodiesel fuel, is prone to crystallization of its high‐melting saturated methyl esters at cold operating temperatures. Removal of saturated esters by winterization was assessed as a means of reducing theTco of methyl soyate. Winterizing neat methyl esters of typical soybean oil produced aTco of −7.1°C, but this was not an efficient way of removing saturated methyl esters because of the low yield (26%) of the separated liquid fraction. However, aTco of −6.5°C with 86% yield was obtained by winterizing the neat methyl esters of a low‐palmitate soybean oil; aTco of −5.8°C with 77% yield was obtained by winterizing methyl esters of normal soybean oil diluted with hexane.
Preparation of sorbitol fatty acid polyesters, potential fat substitutes: Optimization of reaction conditions by response surface methodology
Authors: Chung Ha‐Yull , Park Jiyong , Kim Jung‐Han , Kong Un‐Yong 
Published: December 2006

AbstractEffects of the reaction temperature, reaction time, mole ratio of fatty acid methyl esters (FAME) to sorbitol, and mole ratio of fatty acid sodium soaps (FASS) to sorbitol on yields of sorbitol fatty acid polyester (SFPE) were examined with a response surface methodology. The optimum reaction conditions selected with response surface analysis were as follows: reaction temperature, 144°C; reaction time, 6.65 h; mole ratio of FAME to sorbitol, 10.7∶1; and mole ratio of FASS to sorbitol, 0.77∶1. Under these reaction conditions, the experimental yield of sorbitol fatty acid polyester (mean value: 92% range: 89–94%) obtained from seven replications was close to the predicted value (94%) calculated from the polynomial response surface model equation. The response surface methodology approach used in this study was able to predict the reaction conditions necessary for a high yield of sorbitol fatty acid polyester.
Antioxidative activity and phenolic composition of pilot‐plant and commercial extracts of sage and rosemary
Authors: Cuvelier Marie‐Elisabeth , Richard Hubert , Berset Claudette 
Published: December 2006

AbstractEight sage (Salvia officinalis) and twenty‐four rosemary (Rosmarinus officinalis) extracts, originating from pilot‐plant or commercial sources, had different antioxidative activities as measured by accelerated autoxidation of methyl linoleate. Twenty‐seven compounds were characterized in the Labiatae family extracts by high‐performance liquid chromatography (HPLC) coupled with mass spectrometry, equipped with an atmospheric pressure chemical ionization interface, and by HPLC coupled with a photodiode array spectrophotometer. Twenty‐two compounds were identified, including phenolic acids, carnosol derivatives, and flavonoids. The extracts showed great variation in their HPLC profiles, and no correlation was apparent between their antioxidative efficiency and their composition, in twenty specific phenols. Data indicated that the most effective compounds were carnosol, rosmarinic acid, and carnosic acid, followed by caffeic acid, rosmanol, rosmadial, genkwanin, and cirsimaritin.
Assignment of13C nuclear magnetic resonance signals in fatty compounds with allylic hydroxy groups
Authors: Knothe G. , Bagby M. O. 
Published: December 2006

Abstract13C Nuclear magnetic resonance (NMR) signals in several fatty compounds with allylic mono‐ and dihydroxy groups were assigned by comparing compounds with and without other functional groups (allylic hydroxy, carboxylic acid, respectively, methyl ester at C1). The simple13C NMR spectra of hydroxylated compounds derived from symmetrical alkenes are particularly useful in making assignments. The compounds whose signals were partially assigned are 8‐hydroxy‐9(E)‐octadecenoic acid, 11‐hydroxy‐9(E)‐octadecenoic acid, 8, 11‐dihydroxy‐9(E)‐octadecenoic acid, 9(E)‐octadecen‐8‐ol, and 9(E)‐octadecene‐8, 11‐diol. The present evaluation can be used for assigning signals in other fatty compounds.
A simple and sensitive method for detecting avocado seed oil in various avocado oils
Authors: Werman M. J. , Mokady S. , Neeman I. 
Published: December 2006

AbstractThe presence of avocado seed oil in various avocado oils was detected by thin‐layer chromatography (TLC). An unsaponifiable compound, called Component‐C, was identified in the avocado seed oil. This compound is unique to avocado seed and has a blue color when developed on the TLC plate. At least 9.2 μg of avocado seed unsaponifiables were needed at a single TLC spot to detect the unique blue color definitely. Admixtures of as little as 0.16% avocado seed oil in various avocado oils can be detected by the proposed procedure.
Evaluation of the diffusion coefficient of rapeseed oil during solvent extraction with hexane
Authors: Şaşmaz Dursun Ali 
Published: December 2006

AbstractThe diffusion coefficient of rapeseed oil was determined from data obtained during time‐varied solvent extraction experiments. The experiments were carried out in a Gülbaran extractor‐diffuser with hexane as the solvent. A relationship was found between the slope of the diffusion line and the shape and size of the rapeseed particles. This relation can be used to calculate the diffusion coefficient. A diffusion coefficient of 3.4×10−8 cm2/s was determined from the experimental data.
Effects of arbuscular mycorrhizal infection on the growth and reproduction of the annual legumeKummerowia striatagrowing in a nutrient‐poor alluvial soil
Authors: Nakatsubo Takayuki 
Published: December 2006

AbstractA culture experiment was conducted to examine the effects of arbuscular mycorrhizal (AM) fungi on the growth and reproduction ofKummerowia striata, a common annual legume of river floodplains of Japan. The plants were grown from seeds in pots with nutrient‐poor sandy soil collected from a fluvial bar. Arbuscular mycorrhizal infection increased the aboveground biomass, nodule weight, leaf nitrogen concentration and seed production. However, flowering occurred earlier in plants without AM fungi. These effects of AM fungi were insignificant in plants supplied with phosphate. These results suggest that AM fungi may influence the establishment ofK. striatain nutrient‐poor, disturbed habitats.
Food utilization of aphidophagous hoverfly larvae (Diptera: Syrphidae, Chamaemyiidae) on herbaceous plants in an urban habitat
Authors: Mizuno Masayuki , Itioka Takao , Tatematsu Yoshihiro , Itô Yosiaki 
Published: December 2006

AbstractWe examined food utilization in a community of aphidophagous hoverfly larvae (Diptera: Syrphidae and Chamaemyiidae) in open lands in an urban habitat in central Japan for 3 years. The community consisted of 17 hoverfly species feeding on 20 aphid species occurring on 14 species of dominant herbaceous plants. In terms of larval prey preference, the dominant eight species of hoverfly were categorized into three groups: a polyphagous ‘generalist’ group consisting of four species, Episyrphus balteatus, Betasyrphus serarius, Syrphus vitripennis and Sphaerophoria sp.; an oligophagous ‘specialist’ group consisting of three species, Metasyrphus hakiensis, Dideoides latus and Paragus hemorrhous; and Leucopis puncticornis, which showed a preference for two aphid species on the plant Torilis scabra. The prey aphids of the second group have behavioral or morphological defense mechanisms that are effective for preventing attacks by generalist hoverflies; two prey aphids are aggressive toward generalist predators and the others are protected by ant‐attendance. The specialist hoverflies seem to be adapted to overcome these defense mechanisms. The prey ranges overlapped little between the generalist and the specialist groups, while those within the generalist group overlapped greatly.
Seed germination and seedling survival in a colony of the common cormorant, Phalacrocorax carbo
Authors: Ishida Akira 
Published: December 2006

AbstractGermination and seedling survival of some woody plants were examined in a colony of the common cormorant at Unoyama, central Japan. The germination of Quercus serrata and Pinus densiflora was less successful in the colony than outside the colony. The percentage of germination success was negatively correlated with the amount of cormorant faeces scattered on the ground and also with the soil water conent. Most of the germinated seedlings inside of the colony died with symptoms such as necrosis spreading from the edge of leaves. Saplings of Q. serrata also tended to die more in the colony than outside the colony. The survival rate of Quercus glauca seedlings with scattered faeces on their leaves and/or on the the surrounding soil was significantly lower than the rate of those free of faeces. These results suggest that in the cormorant colony, germination of seeds and seedling survival are greatly inhibited due to both the direct and indirect effects of cormorant faeces.
Application of a rapid thin section method for observations on decomposing litter in mor humus form in a subalpine coniferous forest
Authors: Tian Xing‐jun , Takeda Hiroshi , Ando Tatsuo 
Published: December 2006

AbstractMorphological changes in the decomposing litter ofAbiesspp. andBetulaspp. in a mor humus form were studied by a rapid thin section method. According to the morphological characteristics, the epidermis, mesophyll and vascular bundleof Abiesneedle litter were classified into four types: (i) newly fallen; (ii) slightly decomposed; (iii) moderately decomposed; and (iv) greatly decomposed. The distribution of these tissue types along the profile of the forest floor was then investigated. The morphological changes in other litter types, such as branches, scales andBetulaleaves during decomposition were observed directly with microscope and electron microscope. Five vertical thin sections and 80 horizontal thin sections were used for these observations and investigations. the decomposition ofAbieslitter was slower than that ofBetulalitter. The relative decomposition rate of the tissues was in the order of: mesophyll>vascular bundle >epidermis inAbiesneedles; mesophyll≥epidermis>vascular bundles inBetulaleaves; and inner bark >xylem>outer bark in bothAbiesandBetulabranches. The last remains of the litter were usually stomata, segments of seminiferous scale and outer bark ofAbies. The decomposition of plant litter occurred mainly within the L and F layers of the soil (0–5 cm in depth).Abiesneedles andBetulaleaves completely disappeared at depths of 0–6 cm and 0–4 cm, respectively. Branches disappeared within the top of 5 cm and 6–8 cm forBetulaand forAbies, respectively. The scales ofAbieswere most slowly decomposed in the soil layers.
Mortality can produce predictable dynamics in chaotic populations
Authors: Gonzalez‐Andujar J. L. , Perry J. N. 
Published: December 2006

AbstractRecent theoretical studies have pointed out that a relatively small degree of dispersion between chaotic subpopulations produces predictable, simple dynamics and severely reduces the frequency of the occurrene of chaos. In this paper, we show that the introduction of mortality to models which are initially chaotic, alone or combined with dispersal, can produce similar effects.
Carbon input from plant to soil through root exudation in Digitaria adscendens and Ambrosia artemisiifolia
Authors: Bekku Yukiko , Kimura Makoto , Ikeda Hiroaki , Koizumi Hiroshi 
Published: December 2006

AbstractThe amount of carbon released into soil through root exudation by Digitaria adscendens Herrm. and Ambrosia artemisiifolia L. var. elatior Desc., which often predominate at the early stages of secondary succession, was evaluated in a laboratory experiment conducted over a 60‐day period. Differences in the amount of exuded carbon between these species and between the developmental stages were examined. The amount of carbon exuded increased with growth in both species. The percentage of exuded carbon to photosynthetically net fixed carbon, which was higher at younger stages (13%) in D. adscendens, decreased to 3.1% with time. On the other hand, no reduction in the amount of carbon exuded was observed in A. artemisiifolia (4.7–8.1% range). The total amount of carbon released through root exudation in D. adscendens and A. artemisiifolia was estimated at 3.1% and 6.9% of photosynthetically net fixed carbon, respectively. These results suggest the possibility that wild plants exude a considerable amount of carbon from their roots to the soil, and emphasizes the necessity for considering root exudation in the carbon cycle.