bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microstructure and mechanical properties of poly(L‐lactide) scaffolds fabricated by gelatin particle leaching method
Authors: Zhou Qingliang , Gong Yihong , Gao Changyou 
Published: August 2005

AbstractBiodegradable poly(L‐lactide) (PLLA) scaffolds with well‐controlled interconnected irregular pores were fabricated by a porogen leaching technique using gelatin particles as the porogen. The gelatin particles (280–450 μm) were bonded together through a treatment in a saturated water vapor condition at 70°C to form a 3‐dimensional assembly in a mold. PLLA was dissolved in dioxane and was cast onto the gelatin assembly. The mixtures were then freeze‐dried or dried at room temperature, followed by removal of the gelatin particles to yield the porous scaffolds. The microstructure of the scaffolds was characterized by scanning electron microscopy with respect to the pore shape, interpore connectivity, and pore wall morphology. Compression measurements revealed that scaffolds fabricated by freeze‐drying exhibited better mechanical performance than those by room temperature dying. Along with the increase of the polymer concentration, the porosity of the scaffolds decreased whereas the compressive modulus increased. When the scaffolds were in a hydrated state, the compressive modulus decreased dramatically. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1373–1379, 2005
Emulsion copolymerization of vinyl acetate and 2‐ethyl hexyl acrylate using nonionic emulsifiers in loop reactor
Authors: Sarac Ayfer , Keklik Mehmet , Yildiz Özgür , Yildirim Huseyin 
Published: August 2005

AbstractBatch emulsion copolymerization of vinyl acetate and 2‐ethyl hexyl acrylate (VAc/2EHA = 90 : 10) was initiated by the thermal initiators ammonium persulfate and potassium persulfate at 70°C in the presence of nonylphenol ethoxylates with varying chain lengths and poly(vinyl alcohol). VAc–2EHA copolymer latexes were synthesized as two different series in a loop reactor. The first series was initiated by ammonium persulfate, and the second series was initiated by potassium persulfate. The influence of the counterions or initiators and chain lengths of a nonionic emulsifier on the properties of VAc–2EHA copolymer latexes were determined by measuring the viscosities, weight‐average molecular weights, number‐average molecular weights, molecular weight distribution, and surface tension of latexes to air. The results for the copolymer latexes indicated that some of their physicochemical properties increased with increasing chain length of the nonionic emulsifier, but some of them followed a different trend for the two initiators. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1380–1384, 2005
Acoustic analysis of composite soft materials III: Compressibility of boundary layers around particles of mica and calcium carbonate
Authors: Maebayashi Masahiro , Otsuka Shinya , Matsuoka Tatsuro , Koda Shinobu 
Published: August 2005

AbstractThe velocities of longitudinal, transverse, and leaky surface skimming compressional waves (LSSCW) of polyvinylchloride composite materials were measured as a function of the particle concentration. The mica and calcium carbonate (CC) particles were used as additives. The longitudinal and transverse velocities for the PVC/mica composite increased with the concentration of the mica. In the case of the PVC/CC composite, the transverse velocity increased with the concentration of the CC particle, but the longitudinal velocity was independent of the concentration. The LSSCW velocity for the polyvinylchloride matrix did not change in each composite. The partial specific volume and the partial specific adiabatic compressibility of each particle dispersed in polyvinylchloride were evaluated from sound velocity and density data. The compressibility of the boundary layer around the particles was estimated. The thickness of the boundary layer around the mica particle was estimated. For the PVC/CC composite, on the other hand, a softer phase than the PVC matrix was formed around the CC particle because the compressibility of the boundary layer was larger than that of the PVC matrix. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1385–1392, 2005
Dynamically vulcanized PP/EPDM blends by multifunctional peroxides: Characterization with various analytical techniques
Authors: Datta S. , Naskar K. , Jelenic J. , Noordermeer J. W. M. 
Published: August 2005

AbstractThe characterization of peroxide‐cured PP/EPDM TPVs using various spectroscopic techniques is difficult. These techniques are most suited for analysis of solutions, while the PP‐phase does not dissolve in common organic solvents at room temperature. To obtain more insight into the chemistry and reactivity involved between the multifunctional peroxides and EPDM rubber, several characterization techniques were employed. In the present investigation, FTIR, GC‐(FID + MS), HP‐SEC, and element analysis were used to characterize the multifunctional peroxides TBIB and DTBT, before and after the dynamic curing of the EPDM phase. The decomposition products obtained from these multifunctional peroxides are most likely grafted onto the EPDM‐rubber, thereby reducing their volatility and avoiding the common unpleasant smell. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1393–1403, 2005
The effects of zwitterionic and anionic charge densities in polymer chains on the viscosity behavior of a pH‐responsive hydrophobically modified ionic polymer
Authors: Umar Yunusa , Abu‐Sharkh B. F. , Ali Sk. Asrof 
Published: August 2005

AbstractSulfur dioxide, N,N‐diallyl‐N‐carboethoxymethylammonium chloride, and the hydrophobic monomer N,N‐diallyl‐N‐octadecylammonium chloride were cyclocopolymerized in dimethyl sulfoxide using azobisisobutyronitrile (AIBN) as the initiator to afford water‐soluble cationic polyelectrolytes (CPE) having a five‐membered cyclic structure on the polymeric backbone. The CPE on acidic hydrolysis of the pendent ester groups gave the corresponding cationic acid salts (CAS), which, on treatment with sodium hydroxide, were converted to polybetaines (PB) and anionic polyelectrolytes (APE), as well as polymers PB/APE containing various proportions of zwitterionic (PB) and anionic fractions (APE) in the polymer chain. The solution properties of the CPE, APE, and PB/APE systems containing varying amounts of the hydrophobic monomers in the range 0–4 mol % were investigated by viscometric techniques. Treating the pH‐responsive CAS polymers 4 with different equivalents of NaOH varied the zwitterionic and anionic charge densities in the polymer chain. It was found that the PB/APE polymer with a ratio of 33 : 67 for the zwitterionic and anionic fractions in the polymer chain, respectively, gave the highest viscosity value. The polymers showed that concentration (C*HA) of around 1 g/dL was required for the manifestation of significant hydrophobic associations. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1404–1411, 2005
Schalldämpfer für raumlufttechnische Anlagen in Niedrigenergiehäusern
Authors: Ackermann Ulrich 
Published: August 2005

AbstractDie gute Isolation von Niedrigenergiehäusern erhöht die Gefahr von Schimmelbildung, da der Wasserdampf nicht entweichen kann. Um das Wasser zu entfernen, muß eine raumlufttechnische Anlage installiert werden. Die Strömungskanäle verbinden alle Räume und erzeugen einen akustischen Kurzschluß. Um diese sog. Telefonie zu unterdrücken, müssen Schalldämpfer in die Strömungskanäle eingebaut werden. Die Schalldämpfer erzeugen einen zusätzlichen Druckverlust, der Energie kostet. Die Schalldämpfer wurden deshalb aerodynamisch und akustisch optimiert. Die entwickelten Kulissenschalldämpfer sind aus verhautetem Kunststoff aufgebaut und dadurch gegen Verschmutzung geschützt. Die beste Dämpfung wird zwischen 1000 und 5000 Hz erreicht. In diesem Frequenzbereich ist das menschliche Gehör am empfindlichsten.
Europäische Dämmstoffnormen der 2. Generation: Prüfmethoden zur Ermittlung flüchtiger organischer Komponenten (VOC)
Authors: Gellert Roland , Horn Wolfgang 
Published: August 2005

AbstractDie im Oktober 2001 erschienenen Dämmstoffnormen der 1. Generation DIN EN 13162 (Mineralwolle), DIN EN 13163 (EPS) und folgende (bis DIN EN 13171) verlangen vom Hersteller einen “initial type test (ITT)” von einer notifizierten Prüfstelle – nicht nur für bauphysikalische Eigenschaften wie den Wärmedurchgangswiderstand – sondern auch für die Freisetzung gefährlicher Substanzen. In den Normen wird allerdings noch auf nationale Regelungen verwiesen, da entsprechende Erfahrungen mit europäischen Prüfverfahren nicht vorliegen – auch nationale Erfahrungen liegen nur sehr eingeschränkt vor. Deshalb ist die Entwicklung eines kostengünstigen und praxisrelevanten Prüfverfahrens zur Bestimmung der Emissionen aus Dämmstoffen von normativem Interesse. Es konnte gezeigt werden, daß das Emissionsprüfzellenverfahren (FLEC mit Subunit) gemäß DIN V ENV 13419‐2 vergleichbare Ergebnisse wie das aufwendigere 1‐m3‐Prüfkammerverfahren gemäß DIN V ENV 13419‐1 liefert und damit als Erstprüfverfahren fungieren könnte.
Zur Ermittlung des Energiebedarfs für Kunstlicht in Bürogebäuden – Diskussion von Meßresultaten
Authors: Hoffmann C. , Voss Karsten 
Published: August 2005

AbstractIm Rahmen des Förderkonzeptes Energieoptimiertes Bauen werden Forschung und Demonstration auf dem Gebiet energiesparender Gebäude des Nichtwohnungsbaus gefördert. Das Förderkonzept und die Gebäude wurden 2003 u. a. in dieser Zeitschrift [1, 2] und in einer Buchpublikation [3] vorgestellt. Der vorliegende Beitrag konzentriert sich auf die Auswertung des Bereichs Tageslicht und elektrische Beleuchtung. Neben einer vergleichenden Gegenüberstellung der Projekte wird untersucht, wie wirklichkeitsnah sich der Energiebedarf für elektrische Beleuchtung anhand von Rechenverfahren voraussagen läßt.
Bemessung von Holzdecken aus Hohlkastenelementen im Brandfall
Authors: Frangi Andrea , Fontana Mario 
Published: August 2005

AbstractDer vorliegende Aufsatz stellt eine vereinfachte Berechnungsmethode zur Bemessung von Holzdecken aus Hohlkastenelementen bei Normbrandbeanspruchung vor. Die vereinfachte Berechnungsmethode orientiert sich an der vereinfachten Bemessungsmethode mit reduziertem Querschnitt für Holzbauteile im Brandfall gemäß Eurocode 5 und berücksichtigt zwei unterschiedliche Brandphasen, und zwar vor und nach der vollständigen Verkohlung der unteren, direkt dem Feuer ausgesetzten Holzlamelle. Es wird angenommen, daß die Abbrandgeschwindigkeit während der ersten bzw. zweiten Brandphase konstant über die Zeit ist. Im ersten Teil wird die vereinfachte Berechnungsmethode vorgestellt, der zweite Teil vergleicht die Resultate von Brandversuchen mit der Bemessungsmethode.
Hochschalldämmende Leichtbau‐Trennwände für ein Kino
Authors: Fischer Christian 
Published: August 2005

AbstractMit hochschalldämmenden Trennwänden hat sich die DS‐Plan Ingenieurgesellschaft vor allem in den 1990er Jahren intensiv beschäftigt, als eine große Zahl von Multiplexkinos geplant wurde. Kinobetreiber orientierten sich damals an dem THX‐Manual der Lucasfilm Ltd, in dem unter anderem schallschutztechnische Standards formuliert waren. Zahlreiche Erfahrungen bei der Übertragung der amerikanischen Begrifflichkeiten auf deutsche Kenntnisse und Bauweisen erwiesen sich als hilfreich dabei, einen Kinokomplex in der geforderten Qualität in Leichtbauweise zu erstellen.
Schalldämmung von Gipskarton‐Einfachständerwänden: Einfluß von Veränderungen der Unterkonstruktion
Authors: Wildoer Jörg 
Published: August 2005

AbstractBeim Einsatz von leichten Gipskarton(GK)‐Ständerwänden mit Schallschutzanforderungen ist neben exakter schalltechnischer Planung und Systemauswahl besondere Sorgfalt bei der Ausführung erforderlich. Abweichende Materialparameter oder Systemeigenschaften sind vorab praktisch schwer erkennbar, können jedoch erheblichen Einfluß auf die schalltechnischen Eigenschaften haben. Anhand meßtechnischer Untersuchungen an Trennwänden mit nicht systemkonformer Unterkonstruktion werden die Auswirkungen auf die erreichbare Schalldämmung dargestellt und diskutiert.
Kalibrierung eines Ingenieurmodells zur hygrothermischen Materialcharakterisierung
Authors: Scheffler Gregor , Grunewald John , Häupl Peter 
Published: August 2005

AbstractIm vorliegenden Beitrag wird ein Materialmodell vorgestellt, mit welchem die Verknüpfung komplexer, aus thermodynamischen Grundlagen abgeleiteter Funktionen mit einfachen, in der Ingenieurpraxis bekannten Kennwerten hergestellt wird. Das Modell besitzt dadurch die Vorteile der einfachen Handhabung und der Erweiterbarkeit auf andere Problemstellungen, da es keinen prinzipiell einschränkenden Voraussetzungen bzgl. der Modellierung von Transportvorgängen unterliegt. Im Ergebnis steht ein im gesamten Feuchtebereich kalibriertes, auf thermodynamischen Grundlagen basierendes Transportmodell für gekoppelten Flüssigwasser‐, Wasserdampf‐ und Wärmetransport. Das Modell ist für die wissenschaftliche Weiterentwicklung offen, z. B. auf den Salztransport und Salzkristallisationsprozesse erweiterbar.
Effects of neck exposure to 5.5 mT static magnetic field on pharmacologically modulated blood pressure in conscious rabbits
Authors: Okano Hideyuki , Ohkubo Chiyoji 
Published: August 2005

AbstractStatic magnetic fields (SMF) in the millitesla (mT) range have been reported to modulate microcirculatory hemodynamics and/or blood pressure (BP) under pharmacologically modified state in mammals. This study was designed to investigate the acute effects of local application of a SMF to neck or pelvic region under pharmacologically modulated BP; norepinephrine (NE)‐induced hypertension as well as an L‐type voltage‐gated Ca2+ channel blocker, nicardipine (NIC)‐induced hypotension in conscious rabbits. Magnetic flux densities were up to 5.5 mT and the spatial magnetic gradient peaked in neck (carotid sinus baroreceptor) region at the level of ∼0.06 mT/mm. The duration of exposure was 30 min (including 10 min of pretreatment) and the effects on BP were investigated up to 100 min postexposure. Baroreflex sensitivity (BRS) was estimated from invasive recordings of systolic BP and pulse interval. Neck exposure to 5.5 mT significantly attenuated the pharmacologically induced vasoconstriction or vasodilation, and subsequently suppressed the increase or decrease in BP compared with sham exposure. In contrast, pelvic exposure to 5.5 mT did not significantly antagonized NE‐elevated BP or NIC‐reduced BP. The neck exposure to 5.5 mT has a biphasic and restorative effect on vascular tone and BP acting to normalize the tone and BP. The neck exposure to 5.5 mT caused a significant increase in BRS in NE‐elevated BP compared with sham exposure. The buffering effects of the SMF on increased hemodynamic variability under NE‐induced high vascular tone and NIC‐induced low vascular tone might be, in part, dependent on baroreflex pathways, which could modulate NE‐mediated response in conjunction with Ca2+ dynamics. Bioelectromagnetics 26:469–480, 2005. © 2005 Wiley‐Liss, Inc.
Study of subgridding in SAR computation for the cochlea
Authors: Kopecký Rudolf , Hamnerius Yngve , Persson Mikael 
Published: August 2005

AbstractA 3D subgridding technique is used to model the specific absorption rate (SAR) distribution in the isolated cochlea exposed to mobile phone radiation at 1750 MHz using the FDTD method. The cochlea is modeled using an increasing spatial resolutions of 1, 1/3, 1/5, and 1/7 mm. First simulations were performed at 1 mm spatial resolution. The numerical resolution was then increased to 1/3, 1/5, and 1/7 using subgridding without changing the spatial resolution. A second set of simulations was then performed when both the spatial and numerical resolution were increased together. From the obtained results, we conclude that subgridding is important only when both the numerical resolution of the computational grid and the spatial resolution of the model are increased together. Bioelectromagnetics 26:520–522, 2005. © 2005 Wiley‐Liss, Inc.
Boris Balinsky: transition from embryology to developmental biology
Authors: Korzh Vladimir 
Published: August 2005

AbstractThis is the story of a textbook that students of developmental biology have used for 45 years. “An Introduction to Embryology” was released soon after a role for genes in the control of development became finally recognized but not yet well documented. Thus this book manifested the transition from embryology to developmental biology. The story of its author, Boris Balinsky, who against all odds survived to write this book, is remarkable on its own. He started his scientific career in the USSR, but due to 20th century social and political upheavals, ended it in South Africa. This article will shed light on the life of Boris Balinsky, a scientist and writer and will explore the origins of his book. BioEssays 27:970–977, 2005. © 2005 Wiley Periodicals, Inc.
Evolution of early development of the nervous system: a comparison between arthropods
Authors: Stollewerk Angelika , Simpson Pat 
Published: August 2005

AbstractLarge numbers of cells with unique neuronal specificity are generated during development of the central nervous system of animals. Here we discuss the events that generate cell diversity during early development of the ventral nerve cord of different arthropod groups. Neural precursors are generated in a spatial array in the epithelium of each hemisegment over a period of time. Spatial cues within the epithelium are thought to evolve as embryogenesis proceeds. This spatiotemporal information might generate diversity among the neural precursors in all arthropod groups, although the mechanisms regulating the positioning of individual precursors have diverged. However, distinct strategies for the generation of neuronal diversity have evolved in the different arthropod lineages that appear to correlate with specific modes of ontogenesis. We hypothesize that an evolutionary trend towards reduced cell numbers and possibly rapid embryogenesis in insects has culminated in the appearance of stereotyped neuroblast lineages. BioEssays 27:874–883, 2005. © 2005 Wiley Periodicals, Inc.
Regulation of BRCA1, BRCA2 and BARD1 intracellular trafficking
Authors: Henderson Beric R. 
Published: August 2005

AbstractThe subcellular location and function of many proteins are regulated by nuclear–cytoplasmic shuttling. BRCA1 and BARD1 provide an interesting model system for understanding the influence of protein dimerization on nuclear transport and localization. These proteins function predominantly in the nucleus to regulate cell cycle progression, DNA repair/recombination and gene transcription, and their export to the cytoplasm has been linked to apoptosis. Germ‐line mutations in the BRCA1/BRCA2 and BARD1 genes predispose to risk of breast/ovarian cancer, and certain mutations impair protein function and nuclear accumulation. BRCA1 and BARD1 shuttle between the nucleus and cytoplasm; however heterodimerization masks the nuclear export signals located within each protein, causing nuclear retention of the BRCA1–BARD1 complex and potentially influencing its role in DNA repair, cell survival and regulation of centrosome duplication. This review discusses BRCA1, BRCA2 and BARD1 subcellular localization with emphasis on regulation of transport by protein dimerization and its functional implications. BioEssays 27:884–893, 2005. © 2005 Wiley Periodicals, Inc.
The structure of photosystem I and evolution of photosynthesis
Authors: Nelson Nathan , Ben‐Shem Adam 
Published: August 2005

AbstractOxygenic photosynthesis is the principal producer of both oxygen and organic matter on earth. The primary step in this process—the conversion of sunlight into chemical energy—is driven by four multi‐subunit membrane protein complexes named photosystem I, photosystem II, cytochrome b6f complex and F‐ATPase. Photosystem I generates the most negative redox potential in nature and thus largely determines the global amount of enthalpy in living systems. The recent structural determination of PSI complexes from cyanobacteria and plants sheds light on the evolutionary forces that shaped oxygenic photosynthesis. The fortuitous formation of our solar system in a space plentiful of elements, our distance from the sun and the long time of uninterrupted evolution enabled the perfection of photosynthesis and the evolution of advanced organisms. The available structural information complements the knowledge gained from genomic and proteomic data to illustrate a more precise scenario for the evolution of life systems on earth. BioEssays 27:914–922, 2005. © 2005 Wiley Periodicals, Inc.
Evolution of the neural basis of consciousness: a bird–mammal comparison
Authors: Butler Ann B. , Manger Paul R. , Lindahl B.I.B. , Århem Peter 
Published: August 2005

AbstractThe main objective of this essay is to validate some of the principal, currently competing, mammalian consciousness–brain theories by comparing these theories with data on both cognitive abilities and brain organization in birds. Our argument is that, given that multiple complex cognitive functions are correlated with presumed consciousness in mammals, this correlation holds for birds as well. Thus, the neuroanatomical features of the forebrain common to both birds and mammals may be those that are crucial to the generation of both complex cognition and consciousness. The general conclusion is that most of the consciousness–brain theories appear to be valid for the avian brain. Even though some specific homologies are unresolved, most of the critical structures presumed necessary for consciousness in mammalian brains have clear homologues in avian brains. Furthermore, considering the fact that the reptile–bird brain transition shows more structural continuity than the stem amniote–mammalian transition, the line drawn at the origin of mammals for consciousness by several of the theorists seems questionable. An equally important point is that consciousness cannot be ruled out in the absence of complex cognition; it may in fact be the case that consciousness is a necessary prerequisite for complex cognition. BioEssays 27:923–936, 2005. © 2005 Wiley Periodicals, Inc.
ECM degrading proteases and tissue remodelling in the mammary gland
Authors: Green Kirsty A. , Lund Leif R. 
Published: August 2005

AbstractMatrix degradation and tissue remodelling directed by matrix‐degrading proteases are activated in physiological situations such as wound healing and involution of the prostate, ovaries and uterus. Recently, other activities, in addition to the cleavage of matrix proteins, have been attributed to matrix proteases including the release of growth factors from the extracellular matrix and roles in the maturation of adipocytes. This review describes extracellular proteases, including MMPs, plasminogen and cathepsins involved in the tissue remodelling processes that occur in the breast during pubertal mammary development and the mammary cycle of pregnancy, lactation and weaning. It particularly focuses on development and weaning, termed mammary gland involution, when the majority of remodelling occurs. It also brings together recent findings on the exciting new functions of matrix‐degrading proteases. BioEssays 27:894–903, 2005. © 2005 Wiley Periodicals, Inc.