bluuebunny/crossref_metadata_2025_split huggingface dataset:
Controlled degradation by melt processing with oxygen or peroxide of ethylene/propylene copolymers
Authors: Pucci Andrea , Lorenzi Davide , Coltelli Maria‐Beatrice , Polimeni Giulio , Passaglia Elisa 
Published: July 2004

AbstractEthylene/propylene copolymers with the same composition but different sequence of monomer distribution were submitted to thermal degradation in an inert atmosphere, in the presence of oxygen and/or free radical initiators. The analysis of the reaction products, consisting of lower molecular weight macromolecules with double bonds and oxygenated functional groups, was performed by viscosimetric, FTIR, NMR, and differential scanning calorimetry (DSC) analysis. The presence of linear ethylene blocks of different length with distinct melting temperatures was detected by the self‐annealing methods based on DSC. The results are used to evaluate the effect of the copolymer macromolecules' microstructure and the processing conditions on the degradation extent and the molecular structure of the degradation products. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 372–381, 2004
Verschiebungen des Bodenauflagers bei Baugruben auf der Grundlage der Mobilisierungsfunktion von Besler
Authors: Hettler Achim , Maier Thomas 
Published: July 2004

AbstractIn der Praxis ist es üblich, Baugrubenwände mit dem Trägermodell und unverschieblichen Auflagern zu berechnen. Dabei steht die Annahme eines unverschieblichen Bodenauflagers im Widerspruch zu dem aktivierten Erdwiderstand.Mit Hilfe der Mobilisierungsfunktion von Besler können die Verformungsberechnungen von Baugrubenwänden verbessert werden, indem eine Verschiebung des Bodenauflagers eingeführt wird.Für nichtbindige Böden liegen umfangreiche Untersuchungen vor. Der Ansatz eignet sich auch für bindige Böden, wie gezeigt wird. Allerdings fehlen hier noch grundsätzliche Studien zu den maßgebenden Parametern.
Ein erweitertes physikalisches Modell der pF‐Kurve für teilgesättigte grobkörnige Böden auf primäre Entwässerung und sekundäre Be‐ und Entwässerung
Authors: Zou Yazhou 
Published: July 2004

AbstractDurch Analyse der Bewässerungs‐ und Entwässerungsvorgänge teilgesättigter grobkörniger Böden wird das physikalische Modell in [5] zur Beschreibung der pF‐Kurven bei primärer Entwässerung und bei sekundärer Bewässerung und Entwässerung erweitert. Dabei wird zusätzlich noch der Einfluß eingeschlossener Gasblasen im Porenwasser auf die pF‐Kurve berücksichtigt. Das erweiterte Modell wird durch Versuchsergebnisse verifiziert.
Wiederaufbau des Neuen Museums in Berlin – Tragwerksplanung pro Baudenkmalpflege
Authors: Eisele Gerhard , Gutermann Marc , Seiler Josef , Steffens Klaus 
Published: July 2004

Abstract“Lässt kein Werk sich verstehen ohne dass seine Technik verstanden wäre, lässt diese sowenig sich verstehen ohne Verständnis des Werkes” [1]. Der Wiederaufbau des Neuen Museums in Berlin ist im Sinne Adorno's eine Herausforderung für alle Baubeteiligten. Historische Tragelemente, insbesondere gewölbeartige Bauteile, verfügen in der Regel über erstaunliche Tragfähigkeiten, die allerdings selten durch rechnerische Nachweisführung allein bestätigt werden können. An zwei Beispielen wird aufgezeigt, wie sich rechnerische und experimentelle Tragfähigkeitsanalyse ergänzen und damit Konstruktionselemente von höchster denkmalpflegerischer Bedeutung einer modernen Nutzung zugeführt werden können.
Sanierungsmaßnahmen am Dom St. Marien in Zwickau
Authors: Kühn Michael , Opitz Heinz 
Published: July 2004

AbstractDer Dom St. Marien in Zwickau ist Zeugnis einer 880 Jahre alten und sehr wechselvollen Baugeschichte. Das Gebiet um die spätgotische dreischiffige Hallenkirche hat sich durch den Steinkohlenbergbau um durchschnittlich 4 m gesenkt und 1,30 m nach Südosten bewegt. Dadurch sind am Bauwerk erhebliche Beanspruchungen, Risse und andere Schäden entstanden. Maßnahmen zur Instandsetzung und zur Dauerüberwachung des Bauwerks werden beschrieben.
Sprengabbruch von Stahlbeton‐Schornsteinen
Authors: Werner Diethelm , Melzer Rainer 
Published: July 2004

AbstractDer Sprengabbruch von Schornsteinen aus Stahlbeton wird i. d. R. von spezialisierten Firmen geplant und ausgeführt. Kenntnisse über die mit dem Sprengabbruch verbundenen Vorgänge sind dennoch sowohl für Planungen als auch für die Beratung mit Betroffenen wünschenswert. Da Sprengarbeiten mit i. d. R. beherrschbaren Gefahren verknüpft sind und in der hier betrachteten Größenordnung großes öffentliches Interesse genießen, haben die folgenden Ausführungen auch das Ziel, bestehende Vorurteile abzubauen. Folgende Aspekte sollen beschrieben werden: Fallvorgang, Erschütterungsausbreitung im Boden, Gefährdung benachbarter Bauwerke und weitere Schadensquellen.
Zerstörungsfreie Prüfung von jungem Beton mittels einer Ultraschallreflexionsmethode
Authors: Voigt Thomas , Dehn Frank , Shah Surendra P. 
Published: July 2004

AbstractDie zuverlässige und zerstörungsfreie Bestimmung der Eigenschaften jungen Betons ist ein entscheidender Faktor für den Erfolg und den Fortschritt vieler Bauvorhaben. Der vorliegende Aufsatz beschreibt eine neue Methode zur Charakterisierung zementgebundener Werkstoffe in jungem Alter. Die Methode beruht auf der Messung des Reflexionskoeffizienten (bzw. des Reflexionsverlusts) hochfrequenter Scherwellen an der Grenzfläche zwischen einer Stahlplatte und z. B. Beton. Die beschriebenen Versuche haben gezeigt, daß die Reflexionsmethode in der Lage ist, den Erstarrungs‐ und Erhärtungsprozeß von Beton qualitativ und quantitativ zu beschreiben. Über einen ersten, erfolgreichen Feldversuch wird berichtet.
Progress towards Development of a Cholera Subunit Vaccine
Authors: Taylor Ronald K. , Kirn Thomas J. , Bose Niranjan , Stonehouse Emily , Tripathi Shital A. , Kováč Pavol , Wade William F. 
Published: July 2004

AbstractCholera, an enteric disease that can reach pandemic proportions, remains a world‐wide problem that is positioned to increase in incidence as changes in global climate or armed conflict spawn the conditions that enhance transmission to humans and, thus, precipitate epidemic cholera. An effective subunit cholera vaccine that can provide protective immunity with one parenteral immunization would be a major advantage over the existing oral vaccines that can require two doses for optimal protection. The existing vaccines are clearly effective in some settings, but are less so in others, especially with respect to specific groups such as young (2–5 years) children. In our efforts to develop a cholera subunit vaccine, we focused on two Vibrio cholerae antigens, LPS (lipopolysaccharide) and TCP (toxin co‐regulated pilus), that are known to induce protective antibodies in animal models and, in the case of anti‐LPS antibodies, to be associated with clinical protection of V. cholerae exposed or vaccinated individuals. This review discusses the current cholera vaccines and compares the advantages of a cholera subunit vaccine to that of the whole cell vaccines. We discuss the possible subunit antigens and prospective targeted use of a subunit cholera vaccine.
In the Quest for a Virtual Pseudo Receptor for Sandalwood‐Like Odorants. Part I
Authors: Chapuis Christian 
Published: July 2004

AbstractBased on similarities between naturally occurring (−)‐(Z)‐β‐ or (+)‐(Z)‐α‐santalol ((−)‐ 1 or (+)‐2, resp.) and the reversed (E)‐configured synthetic derivatives from campholenal (7a), a simple model A was developed. Besides reconciliation of this stereochemical aspect, this initial model also tentatively explained the enantiodiscriminations as well as the large spectra of distances separating the OH function from the lipophilic quaternary center(s) reported for different classes of substrates. Evolution, modifications, and refinement of this imperfect model allied with the research for alternative possibilities are illustrated, along with a historical guideline, in the light of olfactively challenging synthetic seco‐substructures as well as literature reports. Despite evolution of the inadequate model A and a plausible interpretation of the lipophilic part, the topological positions of the OH function and its vicinal alkyl substituent could nevertheless not be fully ascertained by this approach. This apparently inconclusive empirical concept prompted us to turn our attention towards a computerized methodology, which will constitute the second and third part of this study.
Glutamine‐dependent changes in gene expression and protein activity
Authors: Curi R. , Lagranha C. J. , Doi S. Q. , Sellitti D. F. , Procopio J. , Pithon‐Curi T. C. 
Published: July 2004

AbstractThe functions of glutamine are many and include, substrate for protein synthesis, anabolic precursor for muscle growth, acid–base balance in the kidney, substrate for ureogenesis in the liver, substrate for hepatic and renal gluconeogenesis, an oxidative fuel for intestine and cells of the immune system, inter‐organ nitrogen transport, precursor for neurotransmitter synthesis, precursor for nucleotide and nucleic acid synthesis and precursor for glutathione production. In the present review information on the mechanism of glutamine action is presented. This amino acid has been shown to regulate the expression of several genes (such as p47phox, p22phox, gp91phox, α‐actin and fibronectin) and activate several proteins (such as ASK1, c‐myc, c‐jun and p70s6k). Copyright © 2004 John Wiley & Sons, Ltd.
NADPH oxidase produces reactive oxygen species and maintains survival of rat astrocytes
Authors: Liu Qing , Kang Jiu‐Hong , Zheng Rong‐Liang 
Published: July 2004

AbstractReactive oxygen species (ROS) produced by activated astrocytes have been considered to be involved in the pathogenesis of neurodegenerative diseases, while NADPH oxidase is an essential enzyme involved in ROS‐mediated signal transduction. The goal of the present study was to determine whether NADPH oxidase plays a role in ROS generation and cell survival in rat astrocytes. We found that the release of ROS in rat astrocytes was significantly increased by stimulation with calcium ionophore or opsonized zymosan, which are known to trigger a respiration burst in phagocytes by the NADPH oxidase pathway. Further study indicated that diphenylene iodonium (DPI), an inhibitor of NADPH oxidase, significantly suppressed the increase of ROS release caused by the calcium ionophore or opsonized zymosan. Cell survival assay and fluorescence double dyeing with acridine orange and ethidium bromide showed that DPI dose‐ and time‐dependently decreased the viability of normal astrocytes, whereas exogenous supplementation of H2O2 can reverse the survival of DPI‐treated astrocytes. For the first time, our results suggest that NADPH oxidase is an important enzyme for the generation of ROS in astrocytes, and the ROS generated by NADPH oxidase play an essential role in astrocyte survival. Copyright © 2004 John Wiley & Sons, Ltd.
The role of student learning outcomes in accreditation quality review
Authors: Beno Barbara A. 
Published: July 2004

AbstractThis chapter is designed to acquaint the reader with the context for accreditors' increased emphasis on student learning outcomes as a key indicator of institutional quality and on the use of learning assessment as a key strategy for guiding institutional improvement. It articulates accreditors' expectations for the presentation of evidence that the institution is using student learning outcomes assessment as part of its quality improvement efforts.
Synthesis, Structures and Electrochemical Properties of Nitro‐ and Amino‐Functionalized Diiron Azadithiolates as Active Site Models of Fe‐Only Hydrogenases
Authors: Liu Tianbiao , Wang Mei , Shi Zhan , Cui Hongguang , Dong Weibing , Chen Jiesheng , Åkermark Björn , Sun Licheng 
Published: July 2004

AbstractComplex [{(μ‐SCH2)2N(4‐NO2C6H4)}Fe2(CO)6] (4) was prepared by the reaction of the dianionic intermediate [(μ‐S)2Fe2(CO)6]2−andN,N‐bis(chloromethyl)‐4‐nitroaniline as a biomimetic model of the active site of Fe‐only hydrogenase. The reduction of4by Pd‐C/H2under a neutral condition afforded complex [{(μ‐SCH2)2N(4‐NH2C6H4)}Fe2(CO)6] (5) in 67 % yield. Both complexes were characterized by IR,1H and13C NMR spectroscopy and MS spectrometry. The molecular structure of4, as determined by X‐ray analysis, has a butterfly 2Fe2S core and the aryl group on the bridged‐N atom slants to the Fe(2) site. Cyclic voltammograms of4and5were studied to evaluate their redox properties. It was found that complex4catalyzed electrochemical proton reduction in the presence of acetic acid. A plausible mechanism of the electrocatalytic proton reduction is discussed.
Scanning fluorescent microscopy analysis is applicable for absolute and relative cell frequency determinations
Authors: Bocsi József , Varga Viktor Sebestyén , Molnár Béla , Sipos Ferenc , Tulassay Zsolt , Tárnok Attila 
Published: July 2004

AbstractBackgroundFlow cytometry (FCM) and laser scanning cytometry (LSC) are the routine techniques for fluorescent cell analysis. Recently, we developed a scanning fluorescent microscopy (SFM) technique. This study compares SFM to LSC (two slide‐based cytometry, SBC, techniques) and FCM, in experimental and clinical settings.MethodsFor the relative cell‐frequency determinations, HT29 colorectal cancer cells and Ficoll separated blood mononuclear cells (FSBMCs) were serially diluted (from 1:1 to 1:1,000) and measured by each of the three techniques. For the absolute cell number determinations (only for SBC) FSBMCs were smeared on slides, then HT29 cells were placed on the slide with a micromanipulator (5–50 cells). Tumor cells circulating in the peripheral blood were isolated by magnetic separation from clinical blood samples of colorectal cancer patients. All samples were double‐stained by CD45 ECD and CAM5.2 FITC antibodies. For slides, TOTO‐3 and Hoechst 33258 DNA dyes were applied as nuclear counter staining.ResultsIn the relative cell frequency determinations, the correlations between the calculated value and measured values by SFM, LSC, and FCM were r2 = 0.79, 0.62, and 0.84, respectively (for all P < 0.01). In the absolute cell frequency determinations, SFM and LSC correlated to a high degree (r2 = 0.97; P < 0.01).ConclusionsSFM proved to be a reliable alternative method, providing results comparable to LSC and FCM. SBC proved to be more suitable for rare‐cell detection than FCM. SFM with digital slides may prove an acceptable adaptation of conventional fluorescent microscopes in order to perform rare‐cell detection. © 2004 Wiley‐Liss, Inc.
Flow cytometric characterization of cell populations in bronchoalveolar lavage and bronchial brushings from patients with chronic obstructive pulmonary disease
Authors: Hodge Sandra J. , Hodge Greg L. , Holmes Mark , Reynolds Paul N. 
Published: July 2004

AbstractBackgroundChronic obstructive pulmonary disease (COPD) is a serious, chronic inflammatory disease of the airway associated with cigarette smoking. Leucocytes are involved in the inflammatory process in the airways in COPD. There is a need for accurate characterization of cellular populations in bronchoalveolar lavage (BAL) due to variation in the predominant cell types reported, which were investigated mostly with manual counting techniques.MethodsBronchial brushings and BAL were obtained from human subjects undergoing fiber optic bronchoscopy. Flow cytometry was applied to identify various cell types. Quenching of autofluorescence of BAL‐derived alveolar macrophages was achieved with η‐octyl β‐D‐galactopyranoside and crystal violet. Comparisons of cell counts obtained with flow cytometric and manual counting methods were performed.ResultsCorrelation analysis showed that manual cell counting methods overestimated the percentage of macrophages when compared with flow cytometric methods (R2 = 0.54). There was also a small tendency by manual counting to underestimate the percentage of lymphocytes and neutrophils. Using flow cytometry, the percentage and absolute numbers of alveolar macrophages and lymphocytes in BAL were not significantly different between patients with COPD and control subjects. The percentage and absolute numbers of neutrophils were higher in BAL from patients with moderate to severe COPD.ConclusionsThis novel flow cytometric assay for identification of various cell types from heterogenous samples of BAL and bronchial brushing will allow further investigation of cell characteristics, such as cytokine production and receptor expression, and an accurate evaluation of apoptosis for different cell types and provide a rationale for urgently required effective treatments for COPD. © 2004 Wiley‐Liss, Inc.
Role of FGFR signaling in the morphogenesis of the Drosophila visceral musculature
Authors: Mandal Lolitika , Dumstrei Karin , Hartenstein Volker 
Published: July 2004

AbstractWe report in this study that the longitudinal visceral muscle founder cells (LVMFs), a population of cells that migrate along the midgut primordium and visceral mesoderm, require the function of the Drosophila fibroblast growth factor receptor (FGFR) homolog, Heartless (Htl). Htl is expressed in LVMFs before and during their migration, and mitogen‐activated protein K (MAPK) activity is present at the same stage. Embryos deficient for htl show an almost complete absence of longitudinal visceral fibers at late stages. In line with previous studies implicating FGFR signaling in morphogenetic movements, we conclude that the defect we observe in htl mutant embryos indicates a role of this signaling pathway in cell migration and/or differentiation of the LVMFs. Given that, in addition to hemocytes, LVMFs are the only cells of the Drosophila embryo that migrate over large distances, we propose that these cells represent a highly suitable system to dissect the role of signaling pathways in cell migration in Drosophila. Developmental Dynamics 231:342–348, 2004. © 2004 Wiley‐Liss, Inc.
Differential tissue development during embryogenesis and regeneration in an annelid
Authors: Myohara Maroko 
Published: July 2004

AbstractThe fragmenting potworm Enchytraeus japonensis (Oligochaeta, Annelida) reproduces asexually by dividing the body into several fragments that then regenerate to complete individuals in 4–5 days. Such large‐scale regeneration, however, occurs only in some invertebrates. To better our understanding of why regeneration is so limited in many animals, despite their ability to undergo embryonic development from the single cell of a fertilized egg, comparisons were made between regeneration and embryonic development of E. japonensis by using two methods: histochemistry for alkaline phosphatase (ALP) and immunohistochemistry with an antibody against acetylated tubulin that visualizes nervous system development. The analyses revealed that both ALP expression patterns and central nervous system development differ between embryogenesis and the regeneration, suggesting that regeneration is not a simple reiteration of embryogenesis but involves different regulatory mechanisms. The study provides a basis for the elucidation of mechanisms that are unique and crucial to regeneration. Developmental Dynamics 231:349–358, 2004. © 2004 Wiley‐Liss, Inc.
Raldh2 expression in optic vesicle generates a retinoic acid signal needed for invagination of retina during optic cup formation
Authors: Mic Felix A. , Molotkov Andrei , Molotkova Natalia , Duester Gregg 
Published: July 2004

AbstractThree retinaldehyde dehydrogenase genes (Raldh1, Raldh2, and Raldh3) expressed in unique spatiotemporal patterns may control synthesis of retinoic acid (RA) needed for retina development. However, previous studies indicate that retina formation still proceeds normally in Raldh1‐/‐ mouse embryos lacking RA synthesis in the dorsal neural retina at the optic cup stage. Here, we demonstrate that Raldh2‐/‐ embryos lacking RA synthesis in the optic vesicle exhibit a failure in retina invagination needed to develop an optic cup. This was also observed in Raldh1‐/‐:Raldh2‐/‐ double mutants, which develop similarly. Both mutants retain RA activity in the lens placode associated with Raldh3 expression, but this RA activity is insufficient to induce optic cup formation. Maternal RA administration at the optic vesicle stage rescues optic cup formation in Raldh2‐/‐ and Raldh1‐/‐:Raldh2‐/‐ embryos, demonstrating that Raldh1 is not required during rescue of optic cup development. The optic cup of rescued Raldh1‐/‐:Raldh2‐/‐ embryos exhibits normal RA activity and this is associated with Raldh3 expression in the retina and lens. Thus, RA signaling initiates in the optic vesicle in response to Raldh2 but can be maintained during optic cup formation by a gene other than Raldh1, most likely Raldh3. Loss of optic vesicle RA signaling does not effect expression of early determinants of retina at the optic vesicle stage (Pax6, Six3, Rx, Mitf). Our findings suggest that RA functions as one of the signals needed for invagination of the retina to generate an optic cup. Developmental Dynamics 231:270–277, 2004. © 2004 Wiley‐Liss, Inc.
Rhombomere boundaries are Wnt signaling centers that regulate metameric patterning in the zebrafish hindbrain
Authors: Riley Bruce B. , Chiang Ming‐Yung , Storch Elly M. , Heck Rebecca , Buckles Gerri R. , Lekven Arne C. 
Published: July 2004

AbstractThe vertebrate hindbrain develops from a series of segments (rhombomeres) distributed along the anteroposterior axis. We are studying the roles of Wnt and Delta–Notch signaling in maintaining rhombomere boundaries as organizing centers in the zebrafish hindbrain. Several wnt genes (wnt1, wnt3a, wnt8b, and wnt10b) show elevated expression at rhombomere boundaries, whereas several delta genes (dlA, dlB, and dlD) are expressed in transverse stripes flanking rhombomere boundaries. Partial disruption of Wnt signaling by knockdown of multiple wnt genes, or the Wnt mediator tcf3b, ablates boundaries and associated cell types. Expression of dlA is chaotic, and cell types associated with rhombomere centers are disorganized. Similar patterning defects are observed in segmentation mutants spiel‐ohne‐grenzen (spg) and valentino (val), which fail to form rhombomere boundaries due to faulty interactions between adjacent rhombomeres. Stripes of wnt expression are variably disrupted, with corresponding disturbances in metameric patterning. Mutations in dlA or mind bomb (mib) disrupt Delta–Notch signaling and cause a wide range of patterning defects in the hindbrain. Stripes of wnt1 are initially normal but subsequently dissipate, and metameric patterning becomes increasingly disorganized. Driving wnt1 expression using a heat‐shock construct partially rescues metameric patterning in mib mutants. Thus, rhombomere boundaries act as Wnt signaling centers required for precise metameric patterning, and Delta signals from flanking cells provide feedback to maintain wnt expression at boundaries. Similar feedback mechanisms operate in the Drosophila wing disc and vertebrate limb bud, suggesting coaptation of a conserved signaling module that spatially organizes cells in complex organ systems. Developmental Dynamics 231:278–291, 2004. © 2004 Wiley‐Liss, Inc.