bluuebunny/crossref_metadata_2025_split huggingface dataset:
Control of nonlinear phenomena in DC–DC converters: Fuzzy logic approach
Authors: Guesmi Kamel , Hamzaoui Abdelaziz , Zaytoon Janan 
Published: January 2008

AbstractDC–DC power converters are characterized by cyclic switching of circuit configurations, which gives rise to a variety of nonlinear behaviours. Their occurrence in DC–DC power converters makes the system analysis, control and behaviour prediction difficult. An enhanced modelling method allowing one to obtain an accurate description of the converter behaviour is presented in this paper. A fuzzy control scheme is proposed, and a fuzzy logic controller is then developed to both suppress converter nonlinear phenomena and ensure the averaged input current regulation for a wide range of parameters' variation. Copyright © 2008 John Wiley & Sons, Ltd.
An efficient algorithm for finding all DC solutions of piecewise‐linear circuits
Authors: Yamamura Kiyotaka , Machida Akinori 
Published: January 2008

AbstractAn efficient algorithm is proposed for finding all DC solutions of transistor circuits where characteristics of transistors are represented by piecewise‐linear (PWL) convex monotone functions. This algorithm is based on a simple test (termed the linear programming, LP, test) for non‐existence of a solution to a system of PWL equations in a given region. In the conventional LP test, the system of PWL equations is transformed into an LP problem by surrounding component PWL functions by rectangles. Then the dual simplex method is applied, by which the number of pivotings per region becomes very small. In this letter, we propose a new LP test using the dual simplex method and triangles. The proposed test is not only efficient but also more powerful than the conventional test using the simplex method or rectangles. Copyright © 2008 John Wiley & Sons, Ltd.
Heteroduplex analysis using flow cytometric microbead assays to detect deletions, insertions, and single‐strand lesions
Authors: Hegedüs Éva , Imre László , Pataki Judit , Lizanecz Erzsébet , Székvölgyi Lóránt , Fazakas Ferenc , Bacsó Zsolt , Tóth Attila , Szabó Miklós , Seres Zoltán , Szabó Gábor 
Published: January 2008

AbstractWe explore the possibilities offered by flow cytometric microbead analysis to develop high throughput methods for the detection of deletions/insertions and single‐strand DNA lesions. The products of PCR reactions derived from reference and test samples are denatured and reannealed, then exposed to enzymatic or chemical treatments distinguishing homoduplices from heteroduplices. The biotin‐ and dye labeled reaction products are immobilized on microbeads and the homo‐ and heteroduplices are assessed in separate fluorescence channels, by flow cytometry. Using a model system based on the mixed lineage leukemia gene breakpoint cluster region, we demonstrate that deletions and insertions in genomic DNA can be detected, using S1 nuclease and chemical cleavage to distinguish hetero‐ from homoduplices, or a restriction enzyme cleaving only the homoduplices. Single‐strand discontinuities can also be detected, by combining nick‐translation, using labeled nucleotide, and flow cytometric microbead analysis. The methodical approaches demonstrated are applicable in a versatile manner in basic cell and molecular biological research and also promise direct application for high throughput screening of genetic diseases and lesions, including insertions or deletions of short sequence elements and single‐strand lesions formed at hypersensitive sites in response to apoptotic stimuli. © 2008 International Society for Analytical Cytology
Myelodysplasia and anemia of chronic disease in human tumor necrosis factor‐α transgenic mice
Authors: Capocasale Renold J. , Makropoulos Dorie A. , Achuthanandam Ram , Stowell Nicole , Quinn John , Rafferty Patricia A. , O'Brien Joanne , Emmell Eva , Bugelski Peter J. 
Published: January 2008

AbstractTNF‐α is a pleitropic cytokine that expresses both pro‐ and anti‐inflammatory activity and transgenic mice expressing human tumor necrosis factor‐α (TNF‐α) exhibit a progressive polyarthritis that models rheumatoid arthritis (RA). One of the common comorbidities of RA is anemia of chronic disease (ACD). The purpose of these experiments was to study the changes in the bone marrow and peripheral blood that accompany polyarthritis in TNF‐α transgenic mice in an effort to better understand the pathogenesis of myelodysplasia and ACD. Polychromatic cytometry, hematology and serum cytokine analysis were used to study the pathogenesis of ACD in human TNF‐α transgenic mice. Our hematological evaluation revealed a mild, compensated, microcytic hypochromic anemia, and monocytosis. In the bone marrow, we observed alterations in cell kinetics, decreased relative expression of transferrin receptor and increased apoptosis and cell death in several late precursor cell populations. Although significant levels of human TNF‐α were found in the serum, neither change in serum murine erythropoietin nor any significant difference observed in serum levels of murine IL‐β, IL‐5, IL‐6, IL‐10, IL‐12(p70), IL‐17, TNF‐α, IFNγ, GM‐CSF, MIP‐1αJE, MCP‐5 was observed. Tg197 mice develop a compensated, microcytic, hypochromic anemia, and a functional iron deficiency by 9 weeks of age. Changes in peripheral blood are reflected in alterations in cell kinetics, transferrin receptor expression and markedly increased apoptosis and cell death in the bone marrow indicating that TNF‐α may contribute to myelodysplasia in ACD. Moreover, since human TNF‐α can interact only with murine TNFR1, our data suggest that TNFR1 may play an important role in the development of ACD © 2008 International Society for Analytical Cytology
Quantification of green fluorescent protein by in vivo imaging, PCR, and flow cytometry: Comparison of transgenic strains and relevance for fetal cell microchimerism
Authors: Fujiki Yutaka , Tao Kai , Bianchi Diana W. , Giel‐Moloney Maryann , Leiter Andrew B. , Johnson Kirby L. 
Published: January 2008

AbstractAnimal models are increasingly being used for the assessment of fetal cell microchimerism in maternal tissue. We wished to determine the optimal transgenic mouse strain and analytic technique to facilitate the detection of rare transgenic microchimeric fetal cells amongst a large number of maternal wild‐type cells. We evaluated two strains of mice transgenic for the enhanced green fluorescent protein (EGFP): a commercially available, commonly used strain (C57BL/6‐Tg(ACTB‐EGFP)10sb/J) (CAG) and a newly created strain (ROSA26‐EGFP) using three different techniques: in vivo and ex vivo fluorescent imaging (for whole body and dissected organs, respectively), PCR amplification of gfp, and flow cytometry (FCM). By fluorescent imaging, organs from CAG mice were 10‐fold brighter than organs from ROSA26‐EGFP mice (P < 0.0001). By PCR, more transgene from CAG mice was detected compared to ROSA26‐EGFP mice (P = 0.04). By FCM, ROSA26‐EGFP cell fluorescence was more uniform than CAG cells. A greater proportion of cells from ROSA26‐EGFP organs were positive for EGFP than cells from CAG organs, but CAG mice had a greater proportion of cells with the brightest fluorescent intensity. Each transgenic strain possesses characteristics that make it useful under specific experimental circumstances. The CAG mouse model is preferable when experiments require brighter cells, whereas ROSA26‐EGFP is more appropriate when uniform or ubiquitous expression is more important than brightness. Investigators must carefully select the transgenic strain most suited to the experimental design to obtain the most consistent and reproducible data. In vivo imaging allows for phenotypic evaluation of whole animals and intact organs; however, we did not evaluate its utility for the detection of rare, fetal microchimeric cells in the maternal organs. Finally, while PCR amplification of a paternally inherited transgene does allow for the quantitative determination of rare microchimeric cells, FCM allows for both quantitative and qualitative evaluations of fetal cells at very high sensitivity in a plethora of maternal organs. © 2008 International Society for Analytical Cytology
Oxidation of intracellular and extracellular fatty acids in skeletal muscle
Authors: Guo ZengKui , Jensen Michael D. , Xu Jinze , Zhou Lianzhen , Persson Xuan‐Mai T. , Balagopal Prabhakaran , Yarasheski Kevin 
Published: January 2008

AbstractFatty acids are a major fuel for many tissues, and abnormal utilization is implicated in diseases. However, tissue fatty acid oxidation has not been determined reliably in vivo. Furthermore, fatty acid oxidation has not been partitioned into intracellular and extracellular components. In this report, a one‐pool model is described that enables direct quantitation of fluxes of intracellular and plasma fatty acids to mitochondria in skeletal muscle using dual stable isotopes and liquid chromatography/electrospray ionization ion‐trap tandem mass spectrometry technology. It is validated by the determination of palmitate oxidation by skeletal muscle in lean and obese rats and the regulation by insulin. Resting postabsorptive intramyocellular and plasma palmitate oxidation by the gastrocnemius muscle was determined to be 3.47 ± 0.8 and 2.06 ± 0.5 nmol/g/min in lean and 6.96 ± 1.8 and 1.34 ± 0.2 nmol/g/min in obese rats, respectively. In obese rats, hyperinsulinemia (1 nmol/L) suppressed intramyocellular (by 59 ± 5% to 2.88 ± 0.3 nmol/g/min; p <0.05) but not plasma (1.41 ± 0.14 nmol/g/min; p >0.05) palmitate oxidation. The fractional turnover rate of palmitoylcarnitine (0.34 ± 0.1/min vs. 0.83 ± 0.2/min; p <0.05) was also suppressed by insulin in obese rats. In obese and lean rats, 83 and 51%, respectively (p = 0.08), of plasma fatty acids traverse the triacylglycerol pool before being oxidized. The results demonstrated that the methodology is feasible and sensitive to metabolic alterations and thus can be used to study fatty acid utilization at tissue level in vivo in a compartmentalized manner for the first time.
Endogenous microflora in turbid virgin olive oils and the physicochemical characteristics of these oils
Authors: Koidis Anastasios , Triantafillou Eleftherios , Boskou Dimitrios 
Published: January 2008

AbstractCloudy olive oil, the fresh olive juice, is an intermediate form before full precipitation of freshly produced olive oil. Some consumers prefer it because they consider it as more natural and less processed. The cloudy form can persist for several months. The oil is a sort of dispersion/suspension system which can be also described as a micro‐emulsion/suspension. Water micro‐droplets were found to have a size ranging from 1 to 5 µm. Cloudiness is due to the low water content and the presence of natural emulsifiers in the oil. The suspension is formed by solid particles (5–60 µm) deriving from the olive fruit. They are present in small amounts (12–460 mg/kg oil). In the newly produced olive oil, containing 0.17–0.49% water, a number of microorganisms of different types (bacteria, yeasts, moulds) were found to survive, but at very low concentrations (<3 log cfu/mL oil). They originate from the exterior of the fruit (epiphytic microflora) and their presence is considered natural. Their enzyme activities do not seem to affect the quality of the final product.
Using lipid profiles and genotypes for the characterization of Corsican olive oils
Authors: Bronzini de Caraffa Virginie , Gambotti Claude , Giannettini Jean , Maury Jacques , Berti Liliane , Gandemer Gilles 
Published: January 2008

AbstractIn 2004, the Corsican producers of olive oils obtained a French protected designation of origin (PDO) “huile d'olive de Corse”, but up to now specifications of Corsican oil production do not clearly indicate the oil attributes related to the territory of production. That is why the fatty acid and triacylglycerol (TAG) compositions of olive oils from the nine main cultivars used to produce oils under PDO were determined and related to the olive variety. The results showed (i) that the nine cultivars covered only four olive varieties, as revealed by random‐amplified polymorphic DNA markers, (ii) that the lipid composition of oils is strongly dependent on the variety, and (iii) that the lipid composition of the four varieties is completely discriminated on the basis of the proportions of four TAG (OOO, OOL, PoOO, OOL) and one fatty acid (18:0). These results clearly establish the relationships between some characteristics of oils and the area of production (Corsica) for at least three varieties that are originated from Corsica. For the fourth variety, other investigations on minor compounds and on sensory attributes of oils must be undertaken to link some oil traits to the territory of production.
Characterization of virgin olive oil from Southern Tunisia
Authors: Zarrouk Wissem , Haddada Faouzia Mahjoub , Baccouri Bechir , Oueslati Imen , Taamalli Wael , Fernandez Xavier , Lizzani‐Cuvelier Louisette , Daoud Douja , Zarrouk Mokhtar 
Published: January 2008

AbstractFruits from three Tunisian cultivars of Olea europea L. grown in the southeast of Tunisia were harvested at the maturity stage of ripeness and immediately processed with a laboratory mill. There are as yet no data on the chemical composition of virgin olive oils from the southeast of Tunisia, an area characterized by an arid condition of growth for olive trees. Our results showed significant differences in the analytical parameters examined for the three cultivars such as fatty acid composition, total phenols and o‐diphenols, and the content of chlorophylls and carotenoids, confirming the importance of genetic factors in the chemical characteristics of the oil. Headspace solid‐phase microextraction (HS‐SPME) was applied to the analysis of volatile compounds of virgin olive oils. Forty‐eight compounds were isolated and characterized by GC‐RI and GC‐MS, representing 94.1–98.1% of the total amount. (E)‐Hex‐2‐enal, the main compound extracted by SPME, characterized the olive oil headspace for all samples. So, it was clearly shown that there were qualitative and quantitative differences in the proportion of volatile constituents from oils of the various cultivars.
Structured lipids from rice bran oil and stearic acid using immobilized lipase from Rhizomucor miehei
Authors: Chopra Rajni , Reddy Sunki Reddy Yella , Sambaiah Kari 
Published: January 2008

AbstractThe major objective of the present study was to prepare structured lipids rich in stearic acid from rice bran oil (RBO) using immobilized lipase (IM 60) from Rhizomucor miehei. The effects of incubation time and temperature, substrate molar ratio, and enzyme load on incorporation of stearic acid were studied. Acidolysis reactions were performed in hexane. Pancreatic lipase‐catalyzed sn‐2 positional analysis and tocopherol analyses were performed before and after enzymatic modification. The kinetics of the reaction was studied and maximum incorporation of stearic acid was observed at 6 h, at 37 °C, when the triacylglycerol and stearic acid molar ratio was maintained at 1 : 6 and the enzyme concentration was 10% of total substrates weight. Stearic acid in RBO after acidolysis was increased from 2.28 to 48.5%, with a simultaneous decrease in palmitic, oleic and linoleic acids. HPLC analysis of tocopherols and tocotrienols was carried out and their content in modified RBO was not significantly affected compared to that of native RBO. The oryzanol content of the modified RBO was reduced from 1.02 to 0.68%. Melting and crystallizing characteristics of the modified fat were studied using differential scanning calorimetry. The total solid fat content at 25 °C increased from 26.12 to 34.8% with an increase in stearic acid incorporation into RBO from 38 to 48%, but it was comparatively less than for cocoa butter and vanaspati. However, the modified RBO completely melted at 37 °C and was useful as plastic fat for various culinary purposes, bakery and confectionary applications. The results of the present study indicated that structured lipids prepared from RBO rich in stearic acid retained their beneficial nutraceuticals; in addition, they do not contain any trans fatty acids.
Determination of total 3‐chloropropane‐1,2‐diol (3‐MCPD) in edible oils by cleavage of MCPD esters with sodium methoxide
Authors: Weißhaar Rüdiger 
Published: January 2008

AbstractA method for the determination of total 3‐chloropropane‐1,2‐diol (3‐MCPD) in edible fats and oils was presented. 3‐MCPD was released from 3‐MCPD fatty acid esters by transesterification with NaOCH3/methanol. After derivatization with phenylboronic acid, 3‐MCPD was determined by GC‐MS. Deuterium‐labeled 3‐MCPD was used as internal standard. In a model experiment, it was shown that acidic hydrolysis with methanol/sulfuric acid, which is normally used for the release of 3‐MCPD from its esters, can cause problems because under acidic conditions additional 3‐MCPD can be formed. No additional 3‐MCPD was formed using NaOCH3/methanol for transesterification. Eleven samples of cold‐pressed and refined safflower oils were analyzed with this method. Levels of total 3‐MCPD were in the range from <100 up to 3200 µg/kg.
Volatile compounds and triacylglycerol composition of original Indian fatty plant oils
Authors: Krist Sabine , Stuebiger Gerald , Bail Stefanie , Unterweger Heidrun 
Published: January 2008

AbstractSome typical original Indian edible and non‐edible fatty plant oils were subject of our investigations. Fundamental research was done on analyzing volatile compounds using HS‐SPME‐GC‐MS. In addition, a sensorial evaluation was applied to receive data on the smell of the samples. Furthermore, the typical and prevailing triacylglycerols (TAG) were investigated by MALDI‐TOF‐MS. Mass spectra reflect the TAG profiles of the whole oil samples based on the detection of [M+Na]+ ions. Oil samples exhibit quite unique TAG profiles, which are suitable for rapid characterization of the original plant oils. The fatty acid composition of the corresponding TAG structures was calculated using lipid analysis software based on the known fatty acid composition. Relative quantification of TAG components was in good agreement with the literature, in case appropriate data are available so far.
Chicken fat dry fractionation: Effects of temperature and time on crystallization, filtration and fraction properties
Authors: Arnaud Elodie , Collignan Antoine 
Published: January 2008

AbstractA surface response experimental design was used to quantify the effects of the final cooling temperature and the residence time at this temperature on the filtration characteristics of the crystal suspension and the quality of the fractions during chicken fat dry fractionation. The crystal morphology was monitored to gain insight into the observed effects. Temperature affected crystallization and the characteristics of the olein and stearin fractions. The crystals became fragmented as the residence time increased, thus leading to a decrease in the filterability of the crystal suspension and an increase in the proportion of the entrained liquid phase. The residence time only affected the quality of the stearin fraction. This time effect was noted at high cooling temperatures in the investigated experimental domain. At low temperatures, increasing the residence time enhanced crystal growth and increased the extent of unsaturation of both fractions without modifying the filtration features.
Improvement of microemulsion electrokinetic chromatography for measuring octanol–water partition coefficients
Authors: Xia Zhining , Jiang Xuemei , Mu Xiaojing , Chen Hua 
Published: January 2008

AbstractMicroemulsion electrokinetic chromatography (MEEKC) has been used to indirectly measure octanol–water partition coefficients (log Pow) of compounds. In order to obtain an accurate log Pow value, the electrophoretic mobilities of the microemulsion phase (μme) and the analyte (μeff) in MEEKC must be accurately required. However, in conventional MEEKC, the shortage of obtaining μme with a tracing method was discovered, and the influences of concentration, injection volume of analyte, and high electric field on measuring μeff were also found. In this paper, a novel method called improved MEEKC (I‐MEEKC) was developed to avoid the problems mentioned above. In I‐MEEKC, a nonlinearity fitting program was used to obtain μme to avoid the error from tracing μme; the extrapolating method was used to eliminate the effects of concentrations and injection volumes of analytes on μeff measurement, and an enough stable microemulsion was selected to eliminate the effect of high electric field on μeff measurement. Then the novel method was applied to estimate log Pow of uncharged compounds and charged pharmaceuticals compared to the conventional MEEKC. The log Pow of all analytes obtained by I‐MEEKC agreed with those obtained by classical shake flask or literature values, the errors between them were within 0.1 logarithm units, better than the ones by conventional MEEKC.
Novel open tubular CEC with tentacle‐type polymer stationary phase functionalized by phenylalanine
Authors: Xu Liang , Sun Yan 
Published: January 2008

AbstractA novel stationary phase with tentacle‐type polymer chains with epoxy groups was fabricated for open tubular CEC. The fabrication procedure of the stationary phase included pretreatment of capillary inner wall, silanization, and glycidyl methacrylate (GMA)‐grafted polymerization. The influence of initiator concentration and polymerization time on the resulting polymer stationary phase was studied by measuring EOF mobility and hydrophobicity of the prepared capillary column. SEM showed that the capillary inner wall was evenly coated with a polymer film showing a wrinkly surface. The prepared GMA‐grafted stationary phase could be easily modified with different chromatographic ligands by the ring‐opening reaction of the epoxy groups. In this study, phenylalanine (Phe) was selected as the ligand. Benzene derivatives and three amino acids were then separated, respectively, using the Phe modified tentacle‐type capillary column. As a control, separations were also performed on a monolayer Phe‐modified capillary. The tentacle‐type polymer stationary phase was found affording stronger retention and better resolution in the separation of benzene derivatives and tryptophan, tyrosine, and Phe mixtures compared with the monolayer stationary phase.
Fabrication of molecularly imprinted hybrid monoliths via a room temperature ionic liquid‐mediated nonhydrolytic sol–gel route for chiral separation of zolmitriptan by capillary electrochromatography
Authors: Wang He‐Fang , Zhu Yi‐Zhou , Lin Jian‐Ping , Yan Xiu‐Ping 
Published: January 2008

AbstractA room temperature ionic liquid (RTIL)‐mediated nonhydrolytic sol–gel (NHSG) protocol was explored for the fabrication of new molecularly imprinted silica‐based hybrid monoliths for chiral separation of a basic template zolmitriptan by CEC. The RTIL‐mediated NHSG protocol involved free‐radical copolymerization and NHSG process. Three carboxylic acids (trifluoromethyl acrylic acid, cinnamic acid, and methacrylic acid (MAA)) were examined as both the functional monomers and the catalysts for the NHSG condensation of methacryloxypropyltrimethoxysilane (MPTMS) to form silica‐based framework. RTIL was incorporated to reduce gel shrinkage and also to act as the pore template. The effects of carboxylic acids and RTIL on the performance of the silica‐based hybrid molecularly imprinted polymer (MIP) monoliths were investigated in detail to realize excellent chiral recognition and to give new insights into the mechanism of the RTIL‐mediated NHSG strategy. Excellent chiral separation of (R)/(S)‐zolmitriptan was achieved when the molar ratio of MAA to MPTMS was 1:4 and 1:2 with RTIL involved. The synergism of the free‐radical copolymerization of the C=C bond of carboxylic acids and MPTMS with the NHSG condensation of MPTMS catalyzed by the carboxylic acids was demonstrated. The incorporation of RTIL increased porosity, and hence improved selectivity of the prepared hybrid monoliths.