bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simulation dynamisch‐thermischen Langzeitverhaltens in Gebäuden mittels CFD
Authors: Zitzmann Tobias , Pfrommer Peter , Cook Malcolm 
Published: April 2006

AbstractDie Planung komplexer Gebäude erfordert immer häufiger den Einsatz von Simulationsprogrammen. Die hierfür derzeit verwendeten dynamischen Gebäudesimulationsprogramme sind jedoch nicht in der Lage, die Luftströmungen und die Temperaturverteilung innerhalb eines Raumes zu erfassen. Eine Lösung der Problematik besteht in der Verlagerung der Gebäudesimulation auf eine CFD‐Plattform, deren Berechnung derzeit allerdings noch mit extrem langen Rechenzeiten und großen Datenmengen verbunden ist. Um diese Rechenzeiten zu verringern, wurde für ANSYS CFX‐5 eine neue Freeze‐Flow‐Methode entwickelt, die auf der periodischen Einfrierung der hydrodynamischen Gleichungen basiert und so dynamische Langzeitsimulationen erlaubt. Zudem wurden die CFD‐Simulationen für die in Räumen vorherrschende freie Konvektion validiert. Im Ergebnis ergaben Freeze‐Flow‐Simulationen einfacher Testmodelle schließlich eine erhebliche Reduzierung der Simulationszeit ohne einhergehenden Verlust an Genauigkeit im Vergleich zur volldynamischen CFD‐Simulation. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Verringerung der Feuchtigkeitsbelastung geschädigter Bauteile durch Temperierung
Authors: Dreyer Jürgen 
Published: April 2006

AbstractWenn der Feuchtigkeitsgehalt in Baustoffen kritische Werte überschreitet, können verschiedenartige Schädigungsmechanismen auftreten. Der sich einstellende Feuchtigkeitsgehalt ist ein Gleichgewichtszustand aus Befeuchtungs‐ und Trocknungsprozessen und hängt somit von deren Intensität und Häufigkeit ab. Zur Verbesserung der Feuchtebilanz kann man durch Sperrschichten oder Dampfbremsen die Feuchtigkeitszufuhr vermindern oder durch diffusionsoffene Schichten die Feuchtigkeitsabfuhr erhöhen. Zur Feuchtigkeitsentlastung werden bei aufsteigender Feuchtigkeit häufig Dränagen und Lüftungskanäle verwendet. Umstritten ist eine Methode, die unter dem Namen “Temperierung von Bauteilen” an einigen Objekten eingesetzt wurde. Die Bauteilbeheizung soll die Verdunstung fördern und so die Feuchtigkeitsbelastung verringern. Bei höheren Temperaturen sinkt die Viskosität stärker als die Oberflächenspannung, so daß Wasser in erwärmten Stoffen schneller kapillar transportiert wird. Allerdings wird dadurch die Verdunstung wesentlich erhöht, so daß in Abhängigkeit von den Geometrien und den klimatischen Bedingungen durchaus der Verdunstungseffekt überwiegen kann und sich der Feuchtigkeitsgehalt verringert. Die durchgeführten Untersuchungen haben gezeigt, daß bei Kalksandstein, Porenbeton, Sand‐ und Kalkstein diese Methode erfolgreich sein kann. Bei Wänden aus Ziegelstein ist diese Methode nicht ohne Einschränkungen zu empfehlen, da hier die Wirkungen sehr unterschiedlich ausfallen können. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Gültigkeit thermischer Behaglichkeitsmodelle
Authors: Hellwig Runa Tabea , Bischof Wolfgang 
Published: April 2006

AbstractZur Zeit führen fehlende Richtlinien für das Raumklima zu Planungsunsicherheit bei frei belüfteten Bürogebäuden in Deutschland. Eine interdisziplinäre Forschungsarbeit wurde durchgeführt, um anhand von Befragungs‐ und Meßdaten zu untersuchen, ob es Unterschiede in der thermischen Behaglichkeit von Personen in frei belüfteten und mechanisch belüfteten Gebäuden gibt. Es werden Befragungs‐ und Meßdaten von 14 Bürogebäuden aus dem ProKlimA‐Projekt verwendet. Die relevante Literatur nennt vier bedeutende Methoden zur Bewertung und Vorhersage der thermischen Behaglichkeit. Auf der einen Seite werden das PMV‐Modell von Fanger sowie eine Modifizierung dieses Modells von Mayer betrachtet. Auf der anderen Seite stehen zwei Ansätze – eine niederländische Richtlinie und ein Ansatz aus einer ASHRAE‐Studie. Im Gegensatz zum PMV‐Modell wird die optimale Raumtemperatur bei diesen zwei Ansätzen in Abhängigkeit von einer mittleren Außentemperatur bestimmt. Die vier Methoden werden auf ihre Eignung für die Bewertung thermischer Behaglichkeit in frei und mechanisch belüfteten Gebäuden untersucht. Der Ansatz nach Mayer erzielt für Personen in mechanisch belüfteten Gebäuden die beste Übereinstimmung mit der Beobachtung. Für frei belüftete Gebäude ist dies der ASHRAE‐Ansatz. Die Ergebnisse zeigen, daß sowohl für freie als auch für mechanische Lüftung neue, bisher in Deutschland und Europa nicht genormte Modelle zur Planung von Behaglichkeit in Räumen erforderlich sind. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Brandschutz in Lüftungsanlagen – die neue Muster‐Lüftungsanlagenrichtlinie M‐LüAR vom September 2005
Authors: Czepuck Knut 
Published: April 2006

AbstractSeit 1984 gibt es die “Lüftungsanlagenrichtlinie”: Richtlinie über brandschutztechnische Anforderungen an Lüftungsanlagen – eine anerkannte technische Baubestimmung. Das Bauordnungsrecht hat sich in der Zwischenzeit deutlich weiterentwickelt. Die zu erwartenden Brände und deren Verläufe sind zwar physikalisch unverändert, aber die Produktentwicklungen und deren weitere Anwendungen sowie die Ausführungen der Gebäude in der Praxis führen zu neuen Lösungswegen. Auch die Erfahrungen aus Bränden der jüngeren Vergangenheit und die veränderte Beurteilung von Risiken und von Einschätzungen zur Brandausbreitung waren zu berücksichtigen. Die M‐LüAR mußte daher auf Aktualität geprüft und an die heutigen Rahmenbedingungen angepaßt werden. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A newly established mutant strain with mild‐type ocular coloboma (retinochoroidal coloboma without microphthalmia) in albino mice
Authors: Matsuura Tetsuro , Kodama Yasushi , Ozaki Kiyokazu , Shirai Shoichiro , Hirasawa Tsutomu , Aoyama Hiroaki , Narama Isao 
Published: April 2006

AbstractBACKGROUNDA complicated malformation of the fundus accompanied by typical ocular coloboma was detected in albino fatty liver Shionogi (FLS) mice. We elucidated a new type of 3‐dimensional anomalous structure inside the eye in this mouse strain.METHODSThe fundi of FLS mice aged 1, 3, 5, and 20 weeks were observed intensively, both macroscopically and by light microscopy. For the prenatal study, coronal serial sections of eyes of FLS embryos were examined by light microscopy on gestation day (GD) 15.0.RESULTSThe frequency of ocular coloboma was almost 70% in FLS mice, and the inheritance mode of this anomaly is suggested to be autosomal recessive with incomplete penetrance. Stereoscopic observation and light microscopy revealed that the mice had characteristic fundus features at any age during the postnatal period. Following ectopic ciliary epithelia, the surface of the retina protruded like a roof, and on the opposite side of the “roof,” a translucent membrane without retinal tissue and choroidal tissue was also consistently detected in the inferior part of the fundus. On GD 15.0, the inner layer and the outer layer were not normally fused at the optic fissure, where a part of the outer layer was absent and the irregular fold of the inner layer was conspicuous in the colobomatous eye of the FLS embryo.CONCLUSIONSThe characteristics of the ocular coloboma in FLS mice are thought to be similar to a mild‐type malformation in humans. These ocular defects seem to be situated along the failed fetal optic fissure. Birth Defects Research (Part A), 2006. © 2006 Wiley‐Liss, Inc.
An anthocyanin/polyphenolic‐rich fruit juice reduces oxidative DNA damage and increases glutathione level in healthy probands
Authors: Weisel Tamara , Baum Matthias , Eisenbrand Gerhard , Dietrich Helmut , Will Frank , Stockis Jean‐Pierre , Kulling Sabine , Rüfer Corinna , Johannes Christian , Janzowski Christine 
Published: April 2006

AbstractOxidative cell damage is involved in the pathogenesis of atherosclerosis, cancer, diabetes and other diseases. Uptake of fruit juice with especially high content of antioxidant flavonoids/polyphenols, might reduce oxidative cell damage. Therefore, an intervention study was performed with a red mixed berry juice [trolox equivalent antioxidative capacity (TEAC): 19.1 mmol/L trolox] and a corresponding polyphenol‐depleted juice (polyphenols largely removed, TEAC 2.4 mmol/L trolox), serving as control. After a 3‐week run‐in period, 18 male probands daily consumed 700 mL juice, and 9 consumed control juice, in a 4‐week intervention, followed by a 3‐week wash‐out. Samples were collected weekly to analyze DNA damage (comet assay), lipid peroxidation (plasma malondialdehyde: HPLC/fluorescence; urinary isoprostanes: GC‐MS), blood glutathione (photometrically), DNA‐binding activity of nuclear factor‐κB (ELISA) and plasma carotenoid/α‐tocopherol levels (HPLC‐DAD). During intervention with the fruit juice, a decrease of oxidative DNA damage (p<5×10–4) and an increase of reduced glutathione (p<5×10–4) and of glutathione status (p<0.05) were observed, which returned to the run‐in levels in the subsequent wash‐out phase. The other biomarkers were not significantly modulated by the juice supplement. Intervention with the control juice did not result in reduction of oxidative damage. In conclusion, the fruit juice clearly reduces oxidative cell damage in healthy probands.
Essential fatty acids: biochemistry, physiology and pathology
Authors: Das Undurti N. 
Published: April 2006

AbstractEssential fatty acids (EFAs), linoleic acid (LA), and α‐linolenic acid (ALA) are essential for humans, and are freely available in the diet. Hence, EFA deficiency is extremely rare in humans. To derive the full benefits of EFAs, they need to be metabolized to their respective long‐chain metabolites, i.e., dihomo‐γ‐linolenic acid (DGLA), and arachidonic acid (AA) from LA; and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from ALA. Some of these long‐chain metabolites not only form precursors to respective prostaglandins (PGs), thromboxanes (TXs), and leukotrienes (LTs), but also give rise to lipoxins (LXs) and resolvins that have potent anti‐inflammatory actions. Furthermore, EFAs and their metabolites may function as endogenous angiotensin‐converting enzyme and 3‐hdroxy‐3‐methylglutaryl coenzyme A reductase inhibitors, nitric oxide (NO) enhancers, anti‐hypertensives, and anti‐atherosclerotic molecules. Recent studies revealed that EFAs react with NO to yield respective nitroalkene derivatives that exert cell‐signaling actions via ligation and activation of peroxisome proliferator‐activated receptors. The metabolism of EFAs is altered in several diseases such as obesity, hypertension, diabetes mellitus, coronary heart disease, schizophrenia, Alzheimer's disease, atherosclerosis, and cancer. Thus, EFAs and their derivatives have varied biological actions and seem to be involved in several physiological and pathological processes.
Yoghurt fermentation at elevated temperatures by strains of Streptococcus thermophilus expressing a small heat‐shock protein: application of a two‐plasmid system for constructing food‐grade strains of Streptococcus thermophilus
Authors: El Demerdash Hassan A. , Oxmann Julian , Heller Knut J. , Geis Arnold 
Published: April 2006

AbstractStreptococcus thermophilus S4 expressing a small heat‐shock protein from the plasmid pSt04‐encoded copy of shsp, is able to carry out fermentation at elevated temperature, i.e., at 50°C. In yoghurt culture together with Lactobacillus delbrueckii subsp. bulgaricus, fermentation at elevated temperature results in a mild yoghurt with low post‐acidification and improved stability of the starter bacteria during storage at 4°C. To transfer pSt04 into commercial S. thermophilus yoghurt starter strains, a two‐plasmid system was constructed. A helper plasmid providing a selectable antibiotic marker, but relying on the repA gene of pSt04, was transformed together with pSt04. After isolation of transformants, the helper plasmid was readily lost upon incubation of transformants in antibiotic‐free medium, thus yielding food‐grade strains carrying pSt04 only. Successful application of the system was demonstrated.
Model‐based analysis and design of a microchannel reactor for tissue engineering
Authors: Mehta Khamir , Linderman Jennifer J. 
Published: April 2006

AbstractRecently developed perfusion micro‐bioreactors offer the promise of more physiologic in vitro systems for tissue engineering. Successful application of such bioreactors will require a method to characterize the bioreactor environment required to elicit desired cell function. We present a mathematical model to describe nutrient/growth factor transport and cell growth inside a microchannel bioreactor. Using the model, we first show that the nature of spatial gradients in nutrient concentration can be controlled by both design and operating conditions and are a strong function of cell uptake rates. Next, we extend our model to investigate the spatial distributions of cell‐secreted soluble autocrine/paracrine growth factors in the bioreactor. We show that the convective transport associated with the continuous cell culture and possible media recirculation can significantly alter the concentration distribution of the soluble signaling molecules as compared to static culture experiments and hence needs special attention when adapting static culture protocols for the bioreactor. Further, using an unsteady state model, we find that spatial gradients in nutrient/growth factor concentrations can bring about spatial variations in the cell density distribution inside the bioreactor, which can result in lowered working volume of the bioreactor. Finally, we show that the nutrient and spatial limitations can dramatically affect the composition of a co‐cultured cell population. Our results are significant for the development, design, and optimization of novel micro‐channel systems for tissue engineering. © 2006 Wiley Periodicals, Inc.
Model of the mass transport to the surface of animal cells cultured in a rotating bioreactor operated in micro gravity
Authors: Rivera‐Solorio Ivan , Kleis Stanley J. 
Published: April 2006

AbstractA mathematical model is used to investigate the transport of dissolved oxygen from the bulk fluid to the surface of aggregates of animal cells cultured in a rotating bioreactor. These aggregates move through different regions of the bioreactor with a local flow field and concentration distribution that vary with time. The time variation of the Sherwood number and the surface concentration for a range of parameters typical of a cell science experiment executed in the Rotating Wall Perfused Vessel (RWPV) bioreactor in space are investigated. The Reynolds numbers experienced by the aggregate are generally low (Re < 1) and the Peclet numbers range from O(1) to O(100). Comparison of the results from the numerical solution of the mathematical model with those from a quasi‐steady model, using a steady‐state correlation for mass transport on a sphere, indicate that the quasi‐steady assumption is not a good model to compute the instantaneous Sherwood number. This indicates a significant history effect in the Sherwood number response to the variations of acceleration of the aggregates in the bioreactor. A high resistance to the mass transport from the bulk fluid to the surface of the aggregate exists for the bioreactor operated in micro gravity. The difference between the surface concentration and the free stream concentration was as high as 30% for aggregates larger than 3 mm. Diffusion reduces the variations of the free stream concentration resulting in a nearly constant value for the concentration at the surface of the aggregates. © 2006 Wiley Periodicals, Inc.
Responses of defense signals, biosynthetic gene transcription and taxoid biosynthesis to elicitation by a novel synthetic jasmonate in cell cultures of Taxus chinensis
Authors: Hu Fengxian , Huang Junhai , Xu Yufang , Qian Xuhong , Zhong Jian‐Jiang 
Published: April 2006

AbstractRecently novel synthetic jasmonate derivatives were shown to have very powerful stimulating effects on the biosynthesis of taxuyunnanine C (Tc) by Taxus chinensis cells (Biotech Bioeng, 86:595; ibid. 86: 809, 2004). To provide an insight into the elicitation mechanism of the newly synthesized elicitors, by taking 2‐hydroxyethyl jasmonate (HEJ, at 100 µM) as a typical example, in this work the defense signals were detected and their influences on the expression of important genes in taxoid biosynthetic pathway were examined in cell cultures of T. chinensis. The oxidative burst (induced H2O2 production) was confirmed, and the induction of lipoxygenase (LOX) activity and intracellular jasmonate acid (JA) synthesis was found. The gene transcription of geranylgeranyl diphosphate synthase (GGPPs) and taxa‐4(5),11(12)‐diene synthase (TS) was up‐regulated by HEJ elicitation compared to control. Inhibition of JA biosynthesis by a putative LOX inhibitor, ibuprofen (IBU), effectively depressed the HEJ‐induced up‐regulation of GGPPs and TS gene transcription levels. In contrast, the inhibition of H2O2 production by membrane NADPH oxidase inhibitor, diphenylene iodonium (DPI), did not affect the transcriptions of those genes. For the HEJ‐induced Tc production, it was suppressed with addition of DPI or IBU. The results suggest that both H2O2 and JA signals were involved in HEJ‐induced Tc biosynthesis, and JA mediated the induction of GGPPs and TS genes expression, but H2O2 was not essential to activate them. Finally, a signal transduction cascade from defense signal response to activated transcription of taxoid biosynthetic genes and enhanced Tc production is proposed. © 2006 Wiley Periodicals, Inc.
Assaying CO2 release for determination of formate dehydrogenase activity in entrapment matrices and aqueous‐organic two‐phase systems
Authors: Ansorge‐Schumacher Marion B. , Steinsiek Sonja , Eberhard Werner , Keramidas Nikolaos , Erkens Klaus , Hartmeier Winfried , Büchs Jochen 
Published: April 2006

AbstractFormate dehydrogenase is an important enzyme for NADH‐regeneration in enzyme‐catalysed reductions. Methods to determine the activity of this biocatalyst during reaction in aqueous‐organic two‐phase systems or after immobilisation were therefore investigated. Determination of gaseous CO2 in the headspace of reaction vessels either by gas chromatography or by pressure sensors was found to be a suitable way for deduction of FDH‐activity in either of these reaction systems. In the presence of organic solvents, gas chromatography yielded more precise data than pressure sensors, while pressure measurements offer the opportunity to assay continuously the activity of entrapped FDH throughout the whole course of reaction. © 2006 Wiley Periodicals, Inc.
Engineering of protein thermodynamic, kinetic, and colloidal stability: Chemical Glycosylation with monofunctionally activated glycans
Authors: Solá Ricardo J. , Al‐Azzam Wasfi , Griebenow Kai 
Published: April 2006

AbstractIn this work we establish the relationship between chemical glycosylation and protein thermodynamic, kinetic, and colloidal stability. While there have been reports in the literature that chemical glycosylation modulates protein stability, mechanistic details still remain uncertain. To address this issue, we designed and coupled monofunctional activated glycans (lactose and dextran) to the model protein α‐chymotrypsin (α‐CT). This resulted in a series of glycoconjugates with variations in the glycan size and degree of glycosylation. Thermodynamic unfolding, thermal inactivation, and temperature‐induced aggregation experiments revealed that chemical glycosylation increased protein thermodynamic (ΔG(25°C)), kinetic (t1/2(45°C)), and colloidal stability. These results highlight the potential of chemical glycosylation with monofunctional activated glycans as a technology for increasing the long‐term stability of liquid protein formulations for industrial and biotherapeutic applications. © 2006 Wiley Periodicals, Inc.
Siderophore production by using free and immobilized cells of two pseudomonads cultivated in a medium enriched with Fe and/or toxic metals (Cr, Hg, Pb)
Authors: Braud Armelle , Jézéquel Karine , Léger Marie‐Anne , Lebeau Thierry 
Published: April 2006

AbstractPseudomonads are serious candidates for siderophore production applied to toxic metal (TM) solubilization. The bioaugmentation of contaminated soils by these TM‐solubilizing bacteria combined with phytoextraction is an emerging clean‐up technology. Unfortunately, siderophore synthesis may be drastically reduced by soluble iron in soils and bacteria can suffer from TM toxicity. In this study, we compared siderophore production by Pseudomonas aeruginosa and Pseudomonas fluorescens by using free and immobilized cells in Ca‐alginate beads incubated in a medium containing Fe and/or TM (mixture of Cr, Hg, and Pb in concentrations which represented the soluble fraction of a contaminated agricultural soil). Free cell growth was stimulated by Fe, whatever the microorganism, the inoculum size and the presence or not of TM might have been. P. aeruginosa was less sensitive to TM than P. fluorescens. By comparison with free cells, immobilization with the high inoculum size showed less sensitivity to TM most probably because of lower metal diffusion in beads. Indeed, a maximum of 99.1% of Cr, 57.4% of Hg, and 99.6% of Pb were adsorbed onto beads. The addition of iron in the culture medium reduced significantly siderophore production of free cells while it led only to a low decrease with their immobilized counterparts, in particular with P. aeruginosa. In culture medium enriched with Fe and/or TM, siderophore‐specific production of immobilized cells was higher than for free cells. © 2006 Wiley Periodicals, Inc.
Claudication secondary to Perclose use after percutaneous procedures
Authors: Jang James J. , Kim Michael , Gray Bruce , Bacharach J. Michael , Olin Jeffrey W. 
Published: April 2006

AbstractThe use of suture‐mediated arterial closure devices has dramatically increased with the increased number of percutaneous procedures being performed. Complications from suture‐mediated closure devices have been underreported. Specifically, arterial stenosis resulting in claudication has not been previously described in detail. We present nine patients who presented with various leg symptoms after Perclose was used to achieve arterial hemostasis following percutaneous procedures. All cases were found to have significant arterial stenoses from the Perclose sutures. Once diagnosis was correctly made, the patients either underwent surgical repair or percutaneous balloon angioplasty and in all cases the symptoms abated. © 2006 Wiley‐Liss, Inc.
Percutaneous replacement of pulmonary valve using the Edwards‐Cribier percutaneous heart valve: First report in a human patient
Authors: Garay Francisco , Webb John , Hijazi Ziyad M. 
Published: April 2006

AbstractWe report on the use of the Edwards‐Cribier percutaneous heart valve (PHV) in a stenotic right ventricle to pulmonary artery homograft in a 16‐year old patient who underwent the Ross operation. Initially, the homograft was stented and at the same procedure, the PHV was deployed inside it. This is the first human case of the application of this valve in the pulmonary valve position. © 2006 Wiley‐Liss, Inc.