bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vertical transport in all‐binary GaAs/AlAs short‐period superlattices and carrier trapping and detrapping dynamics by different quantum wells
Authors: Fujiwara K. , Satake A. , Schrottke L. , Hey R. , Grahn H. T. 
Published: June 2007

AbstractDynamics of vertical transport in all‐binary GaAs/AlAs short‐period superlattices (SPSs) have been investigated as a function of temperature by steady‐state and time‐resolved photoluminescence (PL) experiments. When two different, enlarged quantum wells are embedded in the SPSs, photoexcited carriers compete to be trapped into various localized exciton states and a variety of exciton radiative recombination dynamics appears accompanied by phonon heating. Redistribution of carrier population in the different wells by phonon scattering is significantly influenced by vertical miniband transport in the SPSs. Three different transport regimes are pointed out: (i) tunnelling transport affected by irreversible carrier cooling into deep localized states, (ii) interplay of carrier relaxation and phonon‐assisted activation mediated by an efficient miniband Bloch transport, and (iii) thermalization processes. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hysteresis loops of a bilayer superlattice
Authors: Essaoudi I. , Ainane A. , Saber M. , de Miguel J. J. 
Published: June 2007

AbstractWe apply the effective field theory with a probability distribution technique to study the effects of the interfacial coupling constant and the thickness on the hysteresis of the bilayer. A ferroelectric bilayer with an antiferroelectric interfacial coupling is investigated within the framework of the spin –1/2 Ising model. The effects of the interfacial coupling on the susceptibility and the pyroelectric coefficient are also examined. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A driving simulator with driver monitor system
Authors: Adachi Kazumasa , Kobayashi Fumikazu , Itoh Michimasa , Yamasaki Hatsuo , Nakano Tomoaki , Tsugawa Sadayuki , Yamamoto Shin 
Published: June 2007

AbstractThe driving simulators hitherto developed were intended for investigation of active safety techniques, verification of vehicle movement models, etc., without using an actual vehicle. But there subsequently arose a need for a system that could be used to investigate ways of providing driving and safety assistance to drivers in the aging society of the future. There has been no driving simulator available for such evaluations. The authors have developed a driving simulator for evaluation of driver‐assistance systems with the following installations. A driver monitor camera is installed in the inner mirror unit of the car, and the level of consciousness of the driver is estimated by video processing. A technique for measuring the gaze direction is installed. Techniques for character size transformation in the display and warnings are investigated with reference to the lowered visual acuity of elderly drivers. A verification experiment is performed on braking distance, which is affected by the increased reaction time when the level of consciousness is low. The effectiveness of the system as verified by experiment is reported. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(10): 69– 80, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20469
Spectrum conversion using prosodic information
Authors: Mochizuki Ryo , Okubo Tadashi , Kobayashi Tetsunori 
Published: June 2007

AbstractFor speaker conversion with spectral conversion using GMM, a method is proposed for adding information relating to prosody to the characteristic values and improving conversion precision. In conventional spectral conversion using GMM, only the unaltered spectral parameters are used as input information. However, the voice spectrum is generally related to the closeness of the base frequencies during speech, and therefore, improvement in the quality of the converted voice can be expected with the consideration of prosodic information at the time of conversion. Thus, a method is proposed for spectrum conversion with good precision which assumes the application to actual synthesis by rule, and performs GMM training using the prosodic information of the conversion source and conversion target. Also, the proposed spectrum conversion is applied to speech conversion in a voice synthesis framework. At this time, a method is proposed for preparing triphone joint vectors to ensure training data of a greater number of prosodic conditions using a parallel corpus. A physical evaluation using the cepstrum distance indicates that the use of prosodic information is effective in improving the precision of spectrum conversion. An auditory evaluation was performed of voice quality and speech characteristics after conversion with a conventional method and the proposed method, and indicated that the proposed method is effective in an auditory sense as well. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(10): 12–20, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20667
Structural Color in Porous, Superhydrophilic, and Self‐Cleaning SiO2/TiO2 Bragg Stacks
Authors: Wu Zhizhong , Lee Daeyeon , Rubner Michael F. , Cohen Robert E. 
Published: June 2007

AbstractThin‐film Bragg stacks exhibiting structural color have been fabricated by a layer‐by‐layer (LbL) deposition process involving the sequential adsorption of nanoparticles and polymers. High‐ and low‐refractive‐index regions of quarter‐wave stacks were generated by calcining LbL‐assembled multilayers containing TiO2 and SiO2 nanoparticles, respectively. The physical attributes of each region were characterized by a recently developed ellipsometric method. The structural color characteristics of the resultant nanoporous Bragg stacks could be precisely tuned in the visible region by varying the number of stacks and the thickness of the high‐ and low‐refractive‐index stacks. These Bragg stacks also exhibited potentially useful superhydrophilicity and self‐cleaning properties.
Fetal magnetic resonance imaging in the antenatal diagnosis and management of hydrocolpos
Authors: Picone O. , Laperelle J. , Sonigo P. , Levaillant J.‐M. , Frydman R. , Senat M.‐V. 
Published: June 2007

AbstractHydrocolpos should be considered systematically when an abdominopelvic cystic mass is diagnosed in a female fetus. Because the prognosis and neonatal management of isolated hydrocolpos with spontaneous resolution differs greatly from that of hydrocolpos associated with a cloacal malformation, it is important to ascertain prenatally whether there are associated anomalies. We report the prenatal characteristics of three fetuses with hydrocolpos; in two cases there was spontaneous resolution and one infant was born with digestive tract atresia. The principal ultrasound findings were an oblong anechoic pelvic mass with or without a sagittal septum, located behind a normal bladder. On magnetic resonance imaging (MRI), the cervical imprint on the vagina confirmed the diagnosis of hydrocolpos and helped to diagnose cloacal malformation by demonstrating the absence of meconium beside the bladder on T1 sequences. Our cases show that MRI is useful for differentiating isolated hydrocolpos from hydrocolpos associated with cloacal malformation. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Downstream Processes for Aqueous Enzymatic Extraction of Rapeseed Oil and Protein Hydrolysates
Authors: Zhang Shao Bing , Wang Zhang , Xu Shi Ying 
Published: June 2007

AbstractDownstream processes following aqueous enzymatic extraction (AEE) of rapeseed oil and protein hydrolysates were developed to enhance the oil and protein yields as well as to purify the protein hydrolysates. The wet precipitate (meal residue) from the AEE was washed with twofold water at 60 °C, pH 11 for 1 h. Emulsions from the AEE and the washing step were pooled and submitted to a stepwise demulsification procedure consisting of storage‐centrifugation and freezing–thawing followed by centrifugation. Aqueous phases were pooled and adsorbed onto macroporous adsorption resins (MAR) to remove salts and sugars. Following extensive rinsing with deionized water (pH 4), desorption was achieved by washing with 85% ethanol (v/v) to obtain crude rapeseed peptides (CRPs). In a separate experiment, stepwise desorption was carried out with 25, 55, and 85% ethanol to separate the bitter peptides from the other peptides. Using a combination of the AEE process, washing and demulsification steps, the yields of the total free oil and protein hydrolysates were 88–90% and 94–97%, respectively. The protein recovery was 66.7% and the protein content was enriched from 47.04 to 73.51% in the CRPs. No glucosinolates and phytic acid were detected in the CRPs. From the stepwise desorption, a non‐bitter fraction RP25 (containing 64–66% of total desorbed protein) had a bland color and significantly higher protein content (81.04%) and hence was the more desirable product.
Trans fatty acid determination in fats and margarine by fourier transform infrared spectroscopy using a disposable infrared card
Authors: Ma Kangming , van de Voort F. R. , Sedman J. , Ismail A. A. 
Published: June 2007

AbstractThe use of a disposable polyethylene infrared (IR) card as a sample carrier for the quantitative determination of trans content of fats and oils and margarine by Fourier transform IR spectroscopy was investigated. Standards prepared by dissolving trielaidin in a zero‐trans oil were used to develop partial least squares (PLS) calibrations for both the IR card and a 100‐µm transmission flow cell. These calibrations were then used to predict a series of gas chromatographically‐preanalyzed unknowns, the trans predictions obtained using the card being comparable to those obtained with the transmission flow cell. Somewhat improved performance could be obtained when the spectral data from the card were normalized to compensate for inherent variations in path length and variability in sample loading. Both IR methods tracked the gas chromatographic reference trans values very well. A series of margarine samples was also analyzed by the card method, producing results similar to those obtained using a flow cell. For the analysis of margarines, the card method has the advantage that the trans analysis can be performed directly on microwave melted emulsions because moisture is not retained on the card. Overall, the disposable IR card was shown to work well and has the benefit of allowing trans analyses to be carried out without requiring investment in a heated flow cell or attenuated total reflectance accessory.
Quantitative determination of triacylglycerol profile of structured lipid by capillary supercritical fluid chromatography and high‐temperature gas chromatography
Authors: Lee Theresa W. , Hastilow Christine I. 
Published: June 2007

AbstractTwo analytical methods have been developed for the qualitative and quantitative analyses of triacylglycerol profile of structured lipid (SL)‐containing medium‐chain and long‐chain fatty acids. Supercritical fluid chromatography (SFC) was used in the first method. The SL was dissolved in chloroform/methanol, 95:5 (vol/vol), and analyzed directly using a super‐critical fluid chromatograph equipped with temperature and density programming capabilities. No derivatization was required for sample preparation. An SB‐methyl‐100 capillary column (10 m, 100 µ i.d., 0.25 µ film thickness) was used for the separation of the triacylglycerol species and a flame‐ionization detector (FID) was used for the detection. Supercritical fluid carbon dioxide was used as the mobile phase. In the second method, the SL was hydrogenated to complete saturation prior to analysis using gas chromatography at high temperatures of up to 375°C. A DB‐5HT capillary column (30 m × 0.32 mm i.d., 0.1 µ film thickness) was used for the separation. FID was used for the detection and helium gas was used as mobile phase. The triacylglycerol species were separated and identified based on their equivalent carbon number (ECN), the total carbon number of the acyl side chains. A calibration curve was constructed using a triacylglycerol mixture containing known amounts of monoacyltriacylglycerol standard materials ranging from ECN 18 (trihexanoin) to ECN 66 (tridocosanoin). The novel triacylglycerol species, ECN 32–43, created by the interesterification of medium‐chain triacylglycerol (MCT) and long‐chain triacylglycerol (LCT) were separated and identified based on their retention times. These triacylglycerols, ECN 32–43, were absent in the physical mixture of MCT and LCT. The unique triacylglycerol specieis, ECN 32‐43, were therefore selected as the fingerprinting region for the qualitative identification of the SL. Quantitation of the novel triacylglycerol species in the SL was achieved by using the integrated peak area of the new species. Both methods were employed successfully to distinguish the physical mixture from the corresponding interesterified SL. Results generated by the two methods were compared and found to be in good agreement.
Formation of a Δ7 triterpene alcohol in refined olive oils
Authors: Lanzón A. , Albi T. , Guinda A. 
Published: June 2007

AbstractThe triterpene alcohol fraction in several virgin olive oils and the corresponding oils refined by alkali and by physical processes was analyzed by gas chromatography. A Δ7 compound was detected in all refined olive oils but not in virgin olive oils. This compound was tentatively identified by gas chromatography‐mass spectrometry as 24‐methyl‐5α‐lanosta‐7,24‐dien‐3β‐ol, a 24‐methylenecycloartanol isomer produced during the refining process by the opening of the 9, 19 cyclopropane ring with formation of a double bond in the Δ7 position and the translocation of a double bond in the side chain from the 24–28 to the 24–25 position.
Oxidative stability and AromaScan analyses of corn oils with altered fatty acid content
Authors: Shen N. , Duvick S. , White P. , Pollak L. 
Published: June 2007

AbstractThis project was designed to evaluate the oxidative stability of corn oils with increased total saturated fatty acid composition and to test the feasibility of using the AromaScan, an “electronic nose,” to detect the odors/aromas produced by oxidation. Corn oils with traditional (13.1%) and elevated (14.7 to 17.1%) total saturated fatty acid percentages were evaluated for their oxidative quality. Oils from five corn genotypes were extracted, refined, bleached, and deodorized (RBD) in the laboratory. Two replications, separated at the point of extraction, were evaluated for each genotype. The RBD corn oils (18.0 g) were stored in 50‐mL beakers at 60°C in the dark, and peroxide values were measured every other day for 8 d. Corn oils with elevated saturated fatty acid compositions were more stable (P<0.05) than the traditional corn oil. Aroma intensity of the oils was measured with an AromaScan at days 0, 4, and 8. The AromaScan provided a useful tool to detect odors/aromas produced by oxidation during an oxidative stability study; this tool might be used to partly replace human sensory panel evaluation of oxidized samples.
Heat‐resistant cocoa butter extenders from mahua (Madhuca latifolia) and kokum (Garcinia indica) fats
Authors: Jeyarani T. , Reddy S. Yella 
Published: June 2007

AbstractCocoa butter extenders with heat‐resistant properties were prepared using mahua and kokum fats. The stearin fraction [Fraction (Fr.) 1, 77–80% yield] obtained by solvent fractionation of 50:50 blends of these fats showed a steep melting profile with a higher solid fat content (SFC) at 32.5°C than cocoa butter, even after mixing with it at 25 or 50% levels. The solidification characteristics showed that the Fr. 1 had a supercooling property similar to cocoa butter, but showed higher temperature rise with less crystallization time on the cooling curve, which is advantageous for chocolate molding. Fr. 1 was compatible with cocoa butter at all proportions, as revealed by cooling curves and isothermal solid diagrams. The stearin fraction obtained by dry fractionation of mahua/kokum blend (Fr. 2, 77% yield), though, had similar solidification characteristics and showed lower SFC compared to that of Fr. 1. Fr. 1 and Fr. 2 have high levels of 2‐oleo‐distearin triacylglycerols (46–51%), which are responsible for better stand‐up property at high temperatures compared to cocoa butter. The suitability of the blends of mahua/kokum fats and mahua stearin/kokum fats as cocoa butter extenders was also evaluated. The isothermal solid diagrams showed complete miscibility of the two fats fractions. The results showed that a series of cocoa butter extenders with varying melting characteristics could be prepared by fractionating and by physical blending of mahua and kokum fats in selected proportions.
Antioxidant activity in soybean oil of extracts from thompson grape bagasse
Authors: Gámez‐Meza N. , Noriega‐Rodríguez J. A. , Medina‐Juárez L. A. , Ortega‐García J. , Cázarez‐Casanova R. , Angulo‐Guerrero O. 
Published: June 2007

AbstractThe phenolic compounds of Thompson grape bagasse were extracted using a 95:5 (vol/vol) ethanol/water mixture. Measurement of the antioxidant activity in refined soybean oil of bagasse grape extract was performed by using two different methods, the Rancimat method and the Schaal oven method in conjunction with peroxide value determination. The antioxidant activity of the extract was compared to the tertiary butyl hydroquinone (TBHQ) and butylated hydroxyanisole (BHA) activity. The bagasse grape extract showed similar antioxidant activities in both methods employed. At all concentrations tested [0.1, 0.3 and 0.5% of total phenols (TP)] the extract exhibited appreciable activity, which exceeded the activity of BHA. At some concentrations (0.3 and 0.5% TP) the extract exhibited activity comparable to that of TBHQ. Bagasse is a byproduct with a high content of phenolic compounds and is a good source of natural antioxidants.
Soybean drying in fluidized bed. effect on the hydratable and nonhydratable phosphatide concentration in crude and degummed crude oil
Authors: Tosi Enzo A. , Cazzoli Ampelio , Ré Edmundo , Tapiz Luis 
Published: June 2007

AbstractThe content of nonhydratable phosphatides in soybean crude oil is increased by phospholipase D activity during the oil‐making process. Enzyme inhibition would allow to minimize them. Recently harvested soybeans with high moisture levels require adequate drying to store safely. Simultaneous soybean drying and phospholipase D inactivation in a single operation when applying a thermal treatment by the fluidized‐bed technique was evaluated. The process conditions for performing the drying and a complete enzyme inhibition on soybeans, with an initial moisture content between 7.4 and 20.6% wet basis, similar to that at the time of the harvest, were fluidizing and drying medium temperature between 110 and 140°C, and a drying time between 1 and 2 min. For the treated soybeans, the phosphorus content increased up to 223% in crude oil and decreased 17% in degummed crude oil with regard to the values of the control sample.
Synthesis of geranyl and citronellyl esters of coconut oil fatty acids through alcoholysis by Rhizomucor miehei lipase catalysis
Authors: De B. K. , Chatterjee T. , Bhattacharyya D. K. 
Published: June 2007

AbstractSynthesis of geranyl and citronellyl esters of mixed fatty acids has been investigated by alcoholysis of coconut oil (CNO) using Rhizomucor miehei lipase. CNO fatty acid esters of geraniol and citronellol have unique mild flavors that can be used in food materials. Both geraniolysis and citronellolysis of CNO produce flavor esters in good yield. Depending on substrate concentration the molar yield is more than 50%. The optimized reaction conditions were: pressure, atmospheric; temperature, 50°C; incubation period, 5 h; and Lipozyme, 10% (w/w).
Studies on the enzymatic synthesis of lipophilic derivatives of natural antioxidants
Authors: Stamatis H. , Sereti V. , Kolisis F. N. 
Published: June 2007

AbstractThe esterification of some natural antioxidants such as cinnamic acid derivatives and ascorbic acid in non‐aqueous media, catalyzed by immobilized lipases from Candida antarctica and Rhizomucor miehei, was investigated. The alcohol chain length affected the rate of esterification of cinnamic acids by both lipases. Higher reaction rates were observed when the esterification was carried out with medium‐ or long‐chain alcohols. The rate also depended on aromatic acid structure. The reactivity of the carboxylic function of the cinnamic acids was affected by electron‐donating substituents in the aromatic ring. Higher yields were observed for the esterification of p‐hydroxyphenylacetic acid (97%) catalyzed by C. antarctica lipase and for the esterification of cinnamic acid (59%) catalyzed by R. miehei lipase. Candida antarctica lipase was more suitable for producing ascorbic acid fatty esters, catalyzing with a relatively high yield (up to 65% within 24 h) the regioselective esterification of ascorbic acid with various fatty acids in 2‐methyl‐2‐propanol. The reaction rate and yield depended on the fatty acid chain length and on the molar ratio of reactants. All ascorbic acid fatty esters produced by this procedure exhibited a significant antioxidant activity in a micellar substrate composed of linoleic acid.