bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerische und experimentelle Untersuchung der Randwirbelentwicklung an verschieden ausgeprägten Tragflügelenden
Authors: Wimmer Peter 
Published: April 2003

AbstractDie Ermittlung des induzierten Widerstandes eines Tragflügels ist eine wichtige Aufgabe zur Analyse seiner aerodynamischen Güte. In der Vergangenheit wurden bereits verschiedene Randbogenausformungen entwickelt, um den induzierten Widerstand mithilfe einer Beeinflussung der entstehenden Randwirbelstruktur hinter dem Flügel zu veringern.In dieser Arbeit werden PIV (Particle Image Velocimetry) ‐ Messungen der Geschwindigkeitsfelder des Wirbelnachlaufes an einem Modellflügel in einem Luft‐Schleppwindkanal vorgestellt. Dabei wird die Auswirkung verschiedener Randbögen auf das Wirbelband hinter dem Flügel dargestellt und Simulationsergebnissen gegenübergestellt. Die Simulation der dreidimensionalen Tragflügelumströmung wird dabei mit einem Finite Volumen Verfahren durchgeführt. Verwendung findet ein Solver für reibungsfreie inkompressible Strömungen, wobei bei der Simulation besonderer Wert auf eine Ermittlung der freien Wirbelstruktur hinter dem Tragflügel gelegt wird. Die aus der Diskretisierung des Rechengebietes resultierende numerische Dissipation übersteigt dabei jene aufgrund der natürlichen Viskosität der Luft.Die Simulations‐ und Messergebnisse zeigen, wie die untersuchten Randbogengeometrien den Nachlauf und somit den induzierten Widerstand beeinflussen können.
A comparative study of the steady state and the transient liquid crystal technique for determining the heat transfer coefficients in a bend
Authors: Pape D. , von Wolfersdorf J. , Weigand B. 
Published: April 2003

AbstractFor the investigation of internal and external heat transfer thermochromic liquid crystals (TLC's) have become a very commonly used tool. Today, mainly two different experimental methods with TLC's are in use: The steady state TLC method measuring the wall temperature according to a constant heat flux produced by a heater foil and the transient TLC method measuring the time response of the wall temperature due to a sudden change of the fluid temperature. In the present paper the two different measurement techniques are compared for a very complex 3D flow inside a 180°‐turn of a two‐pass cooling system. From theoretical considerations, the general difference in the heat transfer because of the different wall boundary conditions is shown.
3‐D Inviscid Transonic Condensing Flow around a Swept Wing
Authors: Goodheart K.A. , Dykas S. , Schnerr G.H. 
Published: April 2003

AbstractTransonic condensing flow is an interesting phenomena because of the large change in temperature over a small area. This drop in temperature allows the moist air to condense. It is the purpose of this paper to examine the effect of sweep on condensing flow. The geometry of the wing model starts with NACA‐0014 at the wall and reduces to a NACA‐0010 at the tip. The span of the wing is 2.5 times the maximum chord length. The effect of sweep is examined by comparing a model wing with a sweep angle of 11.3 with a straight trailing edge that has no thickness and then a straight leading edge with a 11.3 trailing edge sweep. The free stream Mach number is 0.8 and angle of attack is 0. A 2‐D calculation shows that the NACA‐0014 and NACA‐0010 have a region of supersonic flow but due to the effect of sweep the sonic line does not extend to the tip. This change of the supersonic region influences the area of condensation on the wing. The swept wing has a lower total drag coefficient for the adiabatic and all condensation cases compared to the straight leading edge wing and second for the each wing the trend of increasing drag with humidity is shown.
PV water pumping systems based on standard frequency converters
Authors: Alonso Abella M. , Lorenzo E. , Chenlo F. 
Published: April 2003

AbstractStandard frequency converters (FCs) are evaluated in this work as a universal solution for photovoltaic (PV) water pumping systems. FCs can be connected directly to a PV generator to power centrifugal submersible pumps driven by three‐phase asynchronous induction motors. In comparison with dedicated products, the use of standard FCs and centrifugal motopumps encompasses several advantages: power range, broad range of products and technological independence. This paper describes the main rules to implement standard FCs in PV pumping systems, and presents a model to estimate its performance from standard pumps manufacturers' data. The experimental validation of the model is also presented. Copyright © 2003 John Wiley & Sons, Ltd.
A high‐efficiency LPE GaAs solar cell at concentrations ranging from 2000 to 4000 suns
Authors: Ortiz Estíbaliz , Algora Carlos 
Published: April 2003

AbstractIII–V solar cells for terrestrial concentration applications are currently becoming of greater and greater interest. From our experience, concentrations higher than 1000 suns are required with these cells to reduce PV electricity cost to such an extent that this alternative could become cost competitive.In this paper, a single‐junctionp/nGaAs solar cell, with efficiencies of 23ċ8 and 22ċ5% at concentration ratios of 2700 and 3600 suns respectively, is presented. This GaAs solar cell is well suited for use with non‐imaging optical concentrators, which possess a large aperture angle. Low‐temperature liquid phase epitaxy (LTLPE) has been the growing technique for the semiconductor structure as an attempt to use a simplified, cheap and clean technique, within a renewable energy perspective.The GaAs solar cell presented is compared with the highest efficiency tandem solar cells at concentration levels exceeding 1000 suns. The GaAs solar cell performance maintains high efficiencies up to 4000 suns, while tandem cells seem to drop very quickly after reaching their maximum. Therefore, single‐junction GaAs solar cells are a good candidate for operating at very high concentrations, and LPE is able to supply these high‐quality solar cells to work within terrestrial concentration systems, the main objective of which is the reduction of PV electricity costs. Copyright © 2003 John Wiley & Sons, Ltd.
Protein expression changes in the Sprague Dawley rat liver proteome following administration of peroxisome proliferator activated receptor α and γ ligands
Authors: White Ian R. , Man Wai J. , Bryant Duncan , Bugelski Peter , Camilleri Patrick , Cutler Paul , Hayes William , Holbrook Joanna D. , Kramer Kerstin , Lord Peter G. , Wood John 
Published: April 2003

AbstractPeroxisome proliferator activated receptors (PPARs) are members of the nuclear receptor superfamily and are intimately involved in lipid metabolism and energy homeostasis. Activation of these receptors in rodents can lead to hepatomegaly and ultimately hepatic carcinogenesis although the mechanisms by which these processes occur are poorly understood. To further our understanding of these processes and to discriminate between different PPAR mediated signalling pathways, a proteomic approach has been undertaken to identify changes in protein expression patterns in Sprague Dawley rat liver following dosing with a PPARα agonist (Wyeth 14643), a PPARγ agonist (Troglitazone) and a compound with mixed PPARα/γ agonist activity (SB‐219994). Using one‐and‐two‐dimensional electrophoresis of tissue lysates a diverse range of protein abundance changes was observed in these tissues. Whilst a number of these proteins have PPAR response elements (PPREs) in their respective promoters, another group was detected whose expression has been documented to be sensitive to peroxisome proliferator administration. Most notably within these groups, proteins involved in lipid catabolism displayed increased expression following drug administration. A further subset of proteins, with less obvious biological implications, also showed altered expression patterns. Where available, sequences upstream of the coding regions of genes not previously known to have PPREs were searched with positional consensus matrices for the presence of PPREs in an attempt to validate these changes. Using such an approach putative PPARγ and PPARδ response elements were discovered upstream of the tubulin β coding region. There was limited overlap in observed protein abundance changes between the three groups, and where this was the case (cytosolic epoxide hydrolase, peroxisomal bifunctional enzyme, hydroxymethyl glutaryl CoA, synthase, long chain acyl‐CoA thioesterase), expression of these proteins had previously been shown to be under the control of PPAR activity.
Proteome analysis of diploid, tetraploid and hexaploid wheat: Towards understanding genome interaction in protein expression
Authors: Islam Nazrul , Tsujimoto Hisashi , Hirano Hisashi 
Published: April 2003

AbstractHexaploid wheat (Triticum aestivum L.) is derived from a complex hybridization procedure involving three diploid species carrying the A, B and D genomes. The proteome patterns of diploid, tetraploid and hexaploid wheat were analyzed to explore the genome interaction in protein expression. At least two species from each of the diploid and tetraploid were used to compare their proteome maps with a hexaploid wheat cv. Chinese Spring. The ancestral cultivars were selected based on their history of closeness with the cultivated wheat. Proteins were extracted from seed flour and separated by two‐dimensional electrophoresis (2‐DE) with isoelectric focusing of pH range from 4–10. 2‐DE maps of cultivated and ancestral species were analyzed by computer assisted image analyzer. The region of high molecular weight glutenin subunits of hexaploid wheat showed similarity with those of the diploid donors, BB and DD genomes. The omega gliadin, which is controlled by B genome in common wheat, was assumed to have evolved as a result of interaction between AA and BB genomes. The low molecular weight glutenins and alpha and beta gliadin regions were contributed by the three genomes. This result suggests that the function of donor genomes particularly in the expression of proteins in hexaploid wheat is not totally independent; rather it is the product of interactions among the diploid genomes in the hexaploid nuclear constitutions. The expression of nonstorage proteins was affected substantially due to the removal of the D genome from hexaploid constitution. Location of the structural gene controlling one of the alpha amylase inhibitor proteins in the nonstorage protein region was identified in the short arm of chromosome 3D.
On asymptotic stability of solitary waves for nonlinear Schrödinger equations
Authors: Buslaev Vladimir S. , Sulem Catherine 
Published: April 2003

We study the long-time behavior of solutions of the nonlinear Schrödinger equation in one space dimension for initial conditions in a small neighborhood of a stable solitary wave. Under some hypothesis on the structure of the spectrum of the linearized operator, we prove that, asymptotically in time, the solution decomposes into a solitary wave with slightly modified parameters and a dispersive part described by the free Schrödinger equation. We explicitly calculate the time behavior of the correction.

Résumé
On étudie le comportement aux temps longs des solutions de l’équation de Schrödinger nonlinéaire unidimensionnelle pour des conditions initiales proches d’une onde solitaire stable. Moyennant des hypothèses sur la structure du spectre de l’opérateur linearisé autour du soliton, on montre qu’asymptotiquement en temps, la solution se décompose en la somme d’une onde solitaire avec des paramètres faiblement modifiés et d’une composante dispersive, solution de l’équation de Schrödinger libre. On calcule explicitement le comportement en temps des termes correctifs.
Effect of pH on Infectivity and Morphology of Ecotropic Moloney Murine Leukemia Virus
Authors: Ye Kaiming , Dhiman Harpreet K. , Suhan Joseph , Schultz Jerome S. 
Published: April 2003

AbstractA number of factors affect the infectivity of retroviruses. The effect of pH on infectivity and morphology of ecotropic moloney murine leukemia virus (MoMuLV) was determined in this work. The ecotropic MoMuLVs were found to remain infectious at a narrow pH range from 5.5 to 8.0. Our experiments indicated that the viruses were inactivated swiftly at lower or higher pH. Within 5 min of exposure to pH 4 about 95% of the viruses lost infectiousness. The viruses were completely inactivated after exposure to pH < 3 or pH >11 for 5 min. The inactivation of MoMuLV was irreversible. Electron microscopy revealed that ecotropic MoMuLV remained round‐shaped at pH between 7.0 and 5. They became irregular with a convex head at pH < 4. At pH 2, virtually all virion particles were penetrated by stains, causing the accumulation of heavy metals inside the particles. The penetration of heavy metal inside the particles indicated the disassociation of the lipid bilayer of the viruses at low pH. A FACS‐based screening strategy for selecting high‐titer retrovirus producing cell lines is also presented in this report.
Lipase‐Mediated Deacetylation and Oligomerization of Lactonic Sophorolipids
Authors: Hu Yongmei , Ju Lu‐Kwang 
Published: April 2003

AbstractThe direct enzymatic polymerization of lactonic sophorolipids (SLs) was investigated with four lipases, including porcine pancreatic lipase (PPL), immobilized Mucor miehei lipase (MML), lyophilized Candida antarctica lipase (Fraction B, CAL‐B), and lyophilized Pseudomonas sp. lipase (PSL). Several organic solvents, covering a wide range of polarity, were compared for suitability as the reaction medium. Isopropyl ether and toluene were found most effective. According to the quantification and structure identification by HPLC and LC‐MS, the reaction proceeded with the formation of monoacetylated lactonic SLs and the subsequent conversion of the intermediates to oligomers and polymers, presumably through ring‐opening polymerization. Temperature was found to have significant effects on the reaction. Both the conversion of reactant SLs and the subsequent formation of oligomers and polymers from the intermediates were faster at 60 °C than at 50 °C. The substrate selectivity among the three dominant reactant SLs also differed with the temperature. The conversion rate increased with the ring size of the lactones at 60 °C, but it decreased with the size at 50 °C.
Production of Phytase by Mucorracemosus in Solid‐State Fermentation
Authors: Bogar Barbara , Szakacs George , Pandey Ashok , Abdulhameed Sabu , Linden James C. , Tengerdy Robert P. 
Published: April 2003

AbstractPhytase production was studied by three Mucor and eight Rhizopus strains by solid‐state fermentation (SSF) on three commonly used natural feed ingredients (canola meal, coconut oil cake, wheat bran). Mucor racemosusNRRL 1994 (ATCC 46129) gave the highest yield (14.5 IU/g dry matter phytase activity) on coconut oil cake. Optimizing the supplementation of coconut oil cake with glucose, casein and (NH4)2SO4, phytase production in solid‐state fermentation was increased to 26 IU/g dry matter (DM). Optimization was carried out by Plackett‐Burman and central composite experimental designs. Using the optimized medium phytase, α‐amylase and lipase production of Mucor racemosusNRRL 1994 was compared in solid‐state fermentation and in shake flask (SF) fermentation. SSF yielded higher phytase activity than did SF based on mass of initial substrate. Because this particular isolate is a food‐grade fungus that has been used for sufu fermentation in China, the whole SSF material (crude enzyme, in situ enzyme) may be used directly in animal feed rations with enhanced cost efficiency.
A Novel Correlation for Protein Diffusion Coefficients Based on Molecular Weight and Radius of Gyration
Authors: He Lizhong , Niemeyer Bernd 
Published: April 2003

AbstractA new correlation is proposed for the prediction of protein diffusion coefficients in free solution. Molecular weight and radius of gyration of proteins are employed as correlation parameters in this method. Both parameters can be easily found in the literature. The correlation works well for diverse proteins with different shapes and extensive molecular weight. Furthermore, this method does not require a preassumption regarding the protein shape while it offers a rapid and convenient calculation with a high accuracy. Also, the proposed correlation can elucidate the estimation deviation of previous correlation methods in the literature.
Enhancement and Prolongation of Baculovirus‐Mediated Expression in Mammalian Cells: Focuses on Strategic Infection and Feeding
Authors: Hu Yu‐Chen , Tsai Chien‐Tai , Chang Yao‐Jen , Huang Jen‐Huang 
Published: April 2003

AbstractThe baculovirus/insect cell system has been widely used for recombinant protein production. Since the finding that baculovirus was able to infect hepatocytes in 1995, various attempts to utilize baculovirus as a gene delivery vehicle into mammalian cells have been reported. In this study, we intended to explore the possibility of utilizing a baculovirus/mammalian cell system as a nonlytic, continuous protein production system. A recombinant baculovirus vector carrying enhanced green fluorescent protein (EGFP) under the control of cytomegalovirus immediate‐early (CMV‐IE) promoter was constructed. This virus was used to infect four common mammalian cell lines, and HeLa was found to yield the highest expression level. Additions of butyrate and valproic acid both enhanced the expression level, but butyrate exhibited a more profound effect. More importantly, HeLa cells were found to be superinfected by baculovirus, a result not observed in the conventional baculovirus/insect cell system. The effects of multiplicity of infection (MOI) and infection timing were also compared. High MOI up to 800 increased the expression in the short term (4 days), but the relatively higher cell death and lower cell density compromised the overall protein yield thereafter. The highest overall expression for a long term was obtained at MOI = 200 when the cells were initially infected at the mid‐exponential phase and superinfected with additional baculovirus (MOI = 200) together with a one‐time supplement of butyrate. In summary, the strategic infection and feeding enhanced the expression level 9‐fold (compared with unsuperinfected culture) and prolonged the duration of expression to 16 days. This study reveals that this baculovirus/mammalian cell system has great potential to become a novel continuous, nonlytic expression system.
Macroaffinity Ligand‐Facilitated Three‐Phase Partitioning (MLFTPP) of α‐Amylases Using a Modified Alginate
Authors: Mondal Kalyani , Sharma Aparna , Lata  , Gupta Munishwar Nath 
Published: April 2003

AbstractThe crude extracts of α‐amylases when mixed with alginate, tert‐butyl alcohol, and ammonium sulfate resulted in an interfacial precipitate containing polymer‐bound amylase. The precipitate was dissolved in 1 M maltose to recover α‐amylase activity. The recovery of α‐amylases were 74%, 77%, and 92% in the case of Bacillus amyloliquefaciens, wheat germ, and porcine pancreas, respectively. All purified preparations showed a single band on SDS‐PAGE.
Co‐Extraction during Reactive Extraction of Phenylalanine using Aliquat 336: Interfacial Mass Transfer
Authors: Pursell Mark R. , Alcina Mendes‐Tatsis M. , Stuckey David C. 
Published: April 2003

AbstractReactive liquid‐liquid extraction can be used to separate hydrophilic fermentation products that would not otherwise partition into nonpolar solvents. However, during extraction of the target solute other compounds present in the extraction medium will also react with the ion exchange reagent and are thus co‐extracted. In this study the effect of co‐extraction on the interfacial flux of the target solute phenylalanine has been investigated for reactive extraction using Aliquat 336. The effect of co‐extracting compounds has been included in a new interfacial flux balance, and experimental results reveal that the interfacial concentrations are equal to the final equilibrium conditions of the system. Using this information a simple mass transfer model has been developed from which film mass transfer coefficients may be determined. Co‐extraction of other compounds present in the feed was found to reduce the interfacial flux of the target solute by reducing the driving force. Co‐extraction did not affect the value of the film mass transfer coefficient, and therefore, co‐extraction does not effect the transport properties of the solute to the interface. Extraction from a multicomponent fermentation broth resulted in a reduced flux, which arises from a reduction in the driving force caused by high levels of co‐extraction. Furthermore, the flux was also reduced as the result of a mass transfer resistance caused by soluble surface‐active compounds present in the fermentation broth adsorbing to the interface. The biomass associated with the fermentation broth was also found to reduce the solute flux, and it is believed that this is due to blockage of the interfacial area.
Use of Process Data To Assess Chromatographic Performance in Production‐Scale Protein Purification Columns
Authors: Larson Tina M. , Davis Jeff , Lam Harry , Cacia Jerry 
Published: April 2003

AbstractTransition analysis was performed on production‐scale chromatography data in order to monitor column performance. Analysis of over 300 transitions from several different chromatography operations demonstrated the utility of the techniques presented. Several of the transitions analyzed occurred on columns with known integrity breaches. The techniques proved sensitive for detection of these breaches. Seven transition calculations are presented, which were combined to produce a single overall integrity value for each column. In addition, principal components analysis (PCA) was used to detect shifts in the transition pattern, including those attributed to integrity breaches. Besides detection of integrity breaches, transition analysis proved useful in monitoring column efficiency over multiple column uses.