bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sea‐island polyurethane/polycarbonate composite nanofiber fabricated through electrospinning
Authors: Liu Ruilai , Cai Ning , Yang Wenqing , Chen Weidu , Liu Haiqing 
Published: December 2009

AbstractSea‐island polyurethane (PU)/polycarbonate (PC) composite nanofibers were obtained through electrospinning of partially miscible PU and PC in 3 : 7 (v/v) N,N‐dimethylformamide (DMF) and tetrahydrofuran (THF) mixture solvent. Their structures, mechanical, and thermal properties were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric (TG), and differential scanning calorimetry (DSC). The structures and morphologies of the nanofibers were influenced by composition ratio in the binary mixtures. The pure PC nanofiber was brittle and easy to break. With increasing the PU content in the PU/PC composite nanofibers, PU component not only facilitated the electrospinning of PC but improved the mechanical properties of PU/PC nanofibrous mats. In a series of nanofibrous mats with varied PU/PC composition ratios, PU/PC 70/30 showed excellent tensile strength of 9.60 Mpa and Young's modulus of 55 Mpa. After selective removal of PC component in PU/PC composite nanofibers by washing with acetone, the residual PU maintained fiber morphology. However, the residual PU nanofiber became irregular and contained elongated indents and ridges along the fiber surface. PU/PC composite fibers showed sea‐island nanofiber structure due to phase separation in the spinning solution and in the course of electrospinning. At PC content below 30%, the PC domains were small and evenly dispersed in the composite nanofibers. As PC content was over 50%, the PC phases became large elongated aggregates dispersed in the composite nanofibers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation, characterization, and drug‐release properties of pH/temperature‐responsive poly(N‐isopropylacrylamide)/chitosan semi‐IPN hydrogel particles
Authors: Chen Xiaochun , Song He , Fang Ting , Bai Jianxin , Xiong Jian , Ying Hanjie 
Published: December 2009

AbstractNovel poly(N‐isopropylacrylamide) (PNIPAAm)/chitosan (CS) semi‐interpenetrating polymer network hydrogel particles were prepared by inverse suspension polymerization. The prepared particles were sensitive to both temperature and pH, and they had good reversibility in solution at different temperatures and pH values. The swelling ratios of PNIPAAm/CS hydrogel particles decreased slightly with the addition of CS, which did not shift the lower critical solution temperature. The drug‐release behavior of the particles was investigated using cyclic adenosine 3′,5′‐monophosphate (cAMP) as a model drug. The release of cAMP from the hydrogel particles was affected by temperature, pH, and the CS content in the particles. These results showed that semi‐IPN hydrogel particles appeared to be of great promise in pH‐ and temperature‐sensitive oral drug release. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Woher kommen die Bemessungswerte der Verbundspannung?
Authors: Lindorf Alexander 
Published: December 2009

Abstract“Wenn über den Verbund neu nachgedacht wird, dann ist es sicher hilfreich, die Überlegungen, die seinerzeit zur Festlegung der Kriterien für die Verbundcharakteristik und der Verbundgüte führten, zu kennen.” Dieser wichtige Gedanke von Rehm soll Ausgangspunkt sein, die vielgestellte Frage nach dem Ursprung der heute gültigen Bemessungswerte der Verbundspannung im Grenzzustand der Tragfähigkeit näher zu betrachten. Die Kenntnis der in der Vergangenheit zugrunde gelegten Kriterien ist für eine Bewertung und Einordnung von bisher wenig untersuchten Einflussparametern auf das Verbundverhalten zwischen Bewehrungsstahl und Beton von großer Bedeutung. Im vorliegenden Aufsatz wird erneut die damalige Diskussion über die Bestimmung von zulässigen Verbundspannungen für Normalbeton direkt aus Verbundversuchen aufgegriffen und diskutiert.
Querschnittsberechnung von Stahlbetonstäben
Authors: Löhning Thomas , Schenk Jochen , Starossek Uwe 
Published: December 2009

AbstractViele Tragwerke aus Stahlbeton lassen sich mit Hilfe von Stabelementen berechnen. Die Einfachheit der Anwendung eines Stabelements steht im Kontrast zur Komplexität der mechanischen und mathematischen Formulierung. Die gesamte Information des realen Stabkontinuums muss auf ein linienförmiges Element projiziert werden. Dies ist insbesondere bei einer nichtlinearen Berechnung eine große Herausforderung. Gilt die Erfassung der geometrischen Nichtlinearität als gelöst, existiert für die materielle Nichtlinearität bislang noch kein etabliertes, allgemein anerkanntes Verfahren für räumliche Stäbe aus Stahlbeton. Die materielle Nichtlinearität wird im Rahmen der Stabtheorie auf Querschnittsebene erfasst. In einer Querschnittsberechnung wird der Spannungs‐ und Dehnungszustand korrespondierend zu den Schnittgrößen bestimmt. Die Grundidee des hybriden Modells ist die Aufteilung des Querschnitts in Bereiche mit einaxialen bzw. zweiaxialen Spannungs‐ und Dehnungszuständen. Der zweiaxiale Bereich wird durch Membranelemente modelliert und beteiligt sich am Abtrag aller sechs Schnittgrößen, während sich der einaxiale auf die beiden Biegemomente und die Normalkraft beschränkt.Cross‐Sectional Analysis of Reinforced Concrete Beams – A Hybrid ApproachMany reinforced concrete structures can be analysed using beam elements. The simplicity of the application of beam elements contrasts the complexity of the mechanical and mathematical formulation. The whole information of the beam continuum has to be projected on an one‐dimensional element. Especially regarding a non‐linear analysis this is a big challenge. The geometrical nonlinearity is regarded as solved. Considering material nonlinearity, however, no established, generally accepted model for spatial reinforced concrete beam elements exists so far. Within beam theory, the material nonlinearity is captured on cross‐sectional level. In a cross‐sectional analysis, the stress and strain state corresponding to sectional forces is determined. The hybrid approach is based on dividing the cross section in areas with uniaxial and biaxial stress and strain states. The biaxial area is modelled by membrane elements and contributes to all six sectional forces. The uniaxial area is restricted to normal force and bending moments.
Verstärkung mit vorgespannten eingeschlitzten Lamellen
Authors: Vorwagner Alois , Burtscher Stefan L. , Grass Günter , Kollegger Johann 
Published: December 2009

AbstractOberflächig geklebte Kohlefaserlamellen (CFK) werden seit vielen Jahren zur Bauteilverstärkung eingesetzt. Die hohe Festigkeit dieser Lamellen kann aufgrund der begrenzten Zugkapazität des Betons nicht zur Gänze ausgenutzt werden. Eingeschlitzte CFK Lamellen hingegen bieten wesentliche Vorteile, die zusammen mit Vorspannung noch weiter optimiert werden können. Für den Vorspannvorgang wurde eine spezielle Verankerung, auf Basis der Composite Wedge Technik, entwickelt, die einfaches und rasches Vorspannen erlaubt. Die Verankerung ist zudem nur 8 kg schwer, was besonders vorteilhaft beim Hantieren an der Tragwerksunterseite ist. Nach dem Vorspannen wird die Verankerung entfernt, die permanente Verankerung der Lamellenenden wird durch nachträgliches Verkleben gewährleistet. Es verbleiben keine Stahlteile im oder am Bauwerk. So zeichnet sich die Konstruktion durch geringen Wartungsaufwand und hohe Dauerhaftigkeit aus. Die Effizienz der entwickelten Systeme wurde an vorgespannten Plattenstreifen experimentell untersucht. In den Untersuchungen konnte die Funktionsfähigkeit nachgewiesen werden.Strengthening using Prestressed Near Surface Mounted StripsExernally bonded carbon fiber reinforced plastic (CFRP) strips are used since several years for strengthening of structures. The high strength of the strips cannot be exploited in most applications. Near surface mounted strips offer several advantages, which allow for further optimization together with prestressing. For the prestressing action a special anchoring device, based on the Composite Wedge Principle, was developed, which allows a simple and quick prestressing procedure. Additionally the anchorage weighs only 8 kg, which is especially beneficial when manipulations on the lower surface of the structure are necessary. The anchorage will be removed after prestressing and the permanent anchorage of the ends of the strips will be established by bond. No steel parts remain in the structure, after completing the strengthening. This results in low maintenance and a high durability. The efficiency of the developed systems and the prestressed plate strips was examined experimentally. In these investigations a perfect functionality could be demonstrated.
p38 Mitogen-activated protein kinase signalling regulates vascular inflammation and epithelial barrier dysfunction in an experimental model of radiation-induced colitis
Authors: Mihaescu A , Santen S , Jeppsson B , Thorlacius H 
Published: December 2009

AbstractBackgroundMicrovascular injury and epithelial barrier dysfunction are rate-limiting aspects in radiation enteropathy. This study examined the role of p38 mitogen-activated protein kinase (p38 MAPK) signalling in radiation-induced colitis in an experimental model.MethodsThe p38 MAPK inhibitor SB239063 was administered to mice immediately before exposure to 20 Gy radiation. Leucocyte– and platelet–endothelium interactions in the colonic microcirculation were assessed by intravital microscopy. Levels of myeloperoxidase (MPO) and CXC chemokines (macrophage inflammatory protein (MIP) 2 and cytokine-induced neutrophil chemoattractant (KC)), and albumin leakage were quantified 16 h after irradiation.ResultsIrradiation induced an increase in leucocyte and platelet recruitment, MPO activity, CXC chemokine levels and intestinal leakage. Inhibition of p38 MAPK by SB239063 decreased radiation-induced leucocyte and platelet recruitment (leucocyte rolling and adhesion by 70 and 90 per cent, both P &lt; 0·001; that of platelets by 70 and 74 per cent, both P &lt; 0·001). It also reduced radiation-provoked increases in colonic MPO activity by 88 per cent (P &lt; 0·001), formation of MIP-2 and KC by 72 and 74 per cent respectively (P = 0·003 and P &lt; 0·001), and intestinal leakage by 81 per cent (P &lt; 0·001).Conclusionp38 MAPK is an important signalling pathway in radiation-induced colitis.
Development and validation of a high‐performance liquid chromatography method for the simultaneous determination of aspirin and folic acid from nano‐particulate systems
Authors: Chaudhary Abhishek , Wang Jeffrey , Prabhu Sunil 
Published: December 2009

AbstractAttention has shifted from the treatment of colorectal cancer (CRC) to chemoprevention using aspirin and folic acid as agents capable of preventing the onset of colon cancer. However, no sensitive analytical method exists to simultaneously quantify the two drugs when released from polymer‐based nanoparticles. Thus, a rapid, highly sensitive method of high‐performance liquid chromatography analysis to simultaneously detect low quantities of aspirin (hydrolyzed to salicylic acid, the active moiety) and folic acid released from biodegradable polylactide‐co‐glycolide (PLGA) copolymer nanoparticles was developed. Analysis was done on a reversed‐phase C18 column using a photodiode array detector at wavelengths of 233 nm (salicylic acid) and 277 nm (folic acid). The mobile phase consisted of acetonitrile–0.1% trifluoroacetic acid mixture programmed for a 30 min gradient elution analysis. In the range of 0.1–100 μg/mL, the assay showed good linearity for salicylic acid (R2 = 0.9996) and folic acid (R2 = 0.9998). The method demonstrated good reproducibility, intra‐ and inter‐day precision and accuracy (99.67, 100.1%) and low values of detection (0.03, 0.01 μg/mL) and quantitation (0.1 and 0.05 μg/mL) for salicylic acid and folic acid, respectively. The suitability of the method was demonstrated by simultaneously determining salicylic acid and folic acid released from PLGA nanoparticles. Copyright © 2009 John Wiley & Sons, Ltd.
Transannular Addition of Phenols to 1,1′‐Dialkynylferrocenes: Unanticipated Formation of Phenoxy[4]ferrocenophanedienes
Authors: Ma Jingxiang , Kühn Björn , Hackl Thomas , Butenschön Holger 
Published: December 2009

AbstractThe reaction of some 1,1′‐dialkynylferrocenes with a variety of phenols in the presence as well as in the absence of [Mo(CO)6] yields good to high yields of phenoxy[4]ferrocenophanedienes. Similar reactivity was observed with a thiophenol and with acetic acid. Reaction under basic reaction conditions led to the formation of the [4]ferrocenophanone 17. The phenoxy[4]ferrocenophanedienes obtained show dynamic behavior as a result of a torsional twist of the carbon bridge as indicated by the 1H and 13C NMR spectra. The reaction mechanism is discussed in view of recent related results of Sato et al. as well as of Pudelski et al. A vinyl cation intermediate is postulated in this context, whose relative stability is evident from the mass spectra of the compounds prepared.
Transcriptional regulatory regions of gap43 needed in developing and regenerating retinal ganglion cells
Authors: Kusik Brandon W. , Hammond Dena R. , Udvadia Ava J. 
Published: December 2009

AbstractMammals and fish differ in their ability to express axon growth‐associated genes in response to CNS injury, which contributes to the differences in their ability for CNS regeneration. Previously we demonstrated that for the axon growth‐associated gene, gap43, regions of the rat promoter that are sufficient to promote reporter gene expression in the developing zebrafish nervous system are not sufficient to promote expression in regenerating retinal ganglion cells in zebrafish. Recently, we identified a 3.6‐kb gap43 promoter fragment from the pufferfish, Takifugu rubripes (fugu), that can promote reporter gene expression during both development and regeneration. Using promoter deletion analysis, we have found regions of the 3.6‐kb fugu gap43 promoter that are necessary for expression in regenerating, but not developing, retinal ganglion cells. Within the 3.6‐kb promoter, we have identified elements that are highly conserved among fish, as well as elements conserved among fish, mammals, and birds. Developmental Dynamics 239:482–495, 2010. © 2009 Wiley‐Liss, Inc.
Expression and regulation of ANTXR1 in the chick embryo
Authors: Herrmann David , Ferrer‐Vaquer Anna , Lahsnig Christian , Firnberg Nicole , Leibbrandt Andreas , Neubüser Annette 
Published: December 2009

AbstractAnthrax Toxin Receptor 1 (ANTXR1; also known as Tumor Endothelial Marker 8, TEM8) is one of several genes that was recently found to be up‐regulated in tumor‐associated endothelial cells. In vitro, the protein can link extracellular matrix components with the actin cytoskeleton to promote cell adhesion and cell spreading. Both, ANTXR1 and the closely related ANTXR2 can bind anthrax toxin and interact with lipoprotein receptor‐related protein 5 and 6, which also work as coreceptors in the WNT signaling pathway. Here, we report the cloning of chick ANTXR1 from a suppression subtractive hybridization screen for fibroblast growth factor (FGF) ‐inducible genes in chicken embryonic facial mesenchyme. We show that chicken ANTXR1 is dynamically expressed throughout embryogenesis, starting from Hamburger and Hamilton stage 10. Furthermore, we demonstrate that FGF signaling is sufficient, but not necessary, to induce ANTXR1 expression in chicken facial mesenchyme. Developmental Dynamics 239:680–687, 2010. © 2009 Wiley‐Liss, Inc.
Medaka Oct4 is expressed during early embryo development, and in primordial germ cells and adult gonads
Authors: Sánchez‐Sánchez Ana V. , Camp Esther , García‐España Antonio , Leal‐Tassias Aránzazu , Mullor José L. 
Published: December 2009

AbstractOct4 is a crucial transcription factor for controlling pluripotency in embryonic stem cells and the epiblast of mouse embryos. We have characterized the expression pattern of medaka (Oryzias latipes) Ol‐Oct4 during embryonic development and in the adult gonads. Genomic analysis showed that Ol‐Oct4 is the ortholog of zebrafish spg/pou2. However, their expression patterns are not the same, suggesting that Oct4 may play different roles in zebrafish and medaka. Using specific antibodies for the Ol‐Oct4 protein, we showed that Ol‐Oct4 is also expressed in primordial germ cells, in the spermatogonia (male germ stem cells), and during different stages of oocyte development. These results suggest that Ol‐Oct4 plays a post‐embryonic role in the maturing gonads and gametes. The Ol‐Oct4 mRNA and protein expression patterns are similar to those of mammalian Oct4 and introduce medaka fish as a valid model for the functional and evolutionary study of pluripotency genes in vivo. Developmental Dynamics 239:672–679, 2010. © 2009 Wiley‐Liss, Inc.
Physical attachment of fluorescent protein particles to atomic force microscopy probes in aqueous media: Implications for surface pH, fluorescence, and mechanical properties studies
Authors: Moreno‐Flores Susana , Georgieva Radostina , Xiong Yu , Melzak Kathryn , Bäumler Hans , Luis Toca‐Herrera José 
Published: December 2009

AbstractTransfer of a fluorescently labeled protein particle from a surface to a microsized scanning probe has been induced by repetitive scanning in aqueous medium. The so‐attached particle can in turn act as a probing tool to study particle–substrate and particle–particle interactions. Attachment of the fluorescent particle occurs at the apical region of an atomic force microscope (AFM) cantilever tip and it endures repetitive loading–unloading cycles against the sample surface. Fluorescence microscopy has been used to address the exact location of the attached particle in the cantilever and to identify the moment when the particle contacts the sample. Moreover, we have observed that fluorescence intensity at the contact point is lower when the probing particle contacts another fluorescent particle than when it contacts the nonfluorescent substrate. The change in fluorescence is attributed to local changes of pH and interparticle‐quenching of fluorophores in the contact region. These findings are promising since they constitute a chemical‐free way to attach bioparticles to AFM probes under fisiological conditions. The atomic force microscopy combined with fluorescence microscopy provides a straight forward method to study particle/particle and particle/substrate interactions, as well as to investigate mechanical properties of biocolloids. Microsc. Res. Tech. 73:746–751, 2010. © 2009 Wiley‐Liss, Inc.
Cytokine stimulation and the choice of promoter are critical factors for the efficient transduction of mouse T cells with HIV‐1 vectors
Authors: Gilham David E. , Lie‐A‐Ling Michael , Taylor Naomi , Hawkins Robert E. 
Published: December 2009

AbstractBackgroundHIV‐1 fails to successfully infect mouse T cells as a result of several blocks in the viral replication cycle. We investigated whether this also impacted on the use of HIV‐1 derived lentiviral vectors for stable gene transfer into mouse T cells.MethodsFreshly isolated primary mouse T cells were immediately mixed with lentiviral vectors encoding an enhanced green fluorescent protein marker gene and transduction frequency was determined after 5 days of culture.ResultsOptimal transduction required both mouse T cell activation and cytokine support. Furthermore, transduction was also dependent upon the promoter chosen, with the rank order of potency being PGK > EF1 > SFFV > CMV. HIV‐1 lentiviral vectors also efficiently transduced cytokine‐stimulated T cells (in the absence of antibody driven T cell activation), albeit with a lower level of transgene expression compared to fully‐activated T cells.ConclusionsThe present study demonstrates that primary mouse T cells can be efficiently transduced with HIV‐1 lentiviral vectors, opening up prospects for their use in mouse models of gene‐modified adoptive cellular therapy. Copyright © 2009 John Wiley & Sons, Ltd.
Improvement of the quality and abatement of the biogenic amines of grass carp muscles by fermentation using mixed cultures
Authors: Liu Zhong‐Yi , Li Zhong‐Hai , Zhong Peng‐Peng , Zhang Ping , Zeng Mu‐Qing , Zhu Chi‐Fang 
Published: December 2009

AbstractBACKGROUND: To improve the quality of processed grass carp (Ctenopharyngodon idellus) products and control the accumulation of hazardous substances therein, minced grass carp slices were salted for 6 h at room temperature and then inoculated with mixed starter cultures of Lactobacillus casei, Streptococcus lactis, Saccharomyces cerevisiae Hansen and Monascus anka and fermented for 12 h at 30 °C. The changes in some characteristics and biogenic amine contents of the fermented muscles were investigated.RESULTS: During the 12 h fermentation at 30 °C, muscles inoculated with mixed starter cultures showed a rapid decrease in pH from 6.0 to 5.1 and suppression of the growth of enterobacteria and pseudomonads. The fermented muscles exhibited better colour, appearance, flavour and overall acceptability than the control (P < 0.05). The changes in non‐protein nitrogen and free amino acid contents of the fermented muscles and in their sodium dodecyl sulfate polyacrylamide gel electrophoresis profiles indicated that severe hydrolysis of muscle proteins occurred during fermentation. The accumulation of biogenic amines in the muscles was efficiently reduced by fermentation with mixed starter cultures.CONCLUSION: Fermentation with mixed starter cultures of L. casei, S. lactis, S. cerevisiae Hansen and M. anka significantly improved the characteristics of grass carp muscles and controlled the accumulation of biogenic amines. Copyright © 2009 Society of Chemical Industry
Cereal‐based bioproducts containing polyunsaturated fatty acids
Authors: Certik Milan , Adamechova Zuzana 
Published: December 2009

AbstractOne of the main targets of high‐value oils is focused on polyunsaturated fatty acids (PUFAs) that have been incorporated into several products ranging through feeds, foods, cosmetics and pharmaceuticals. Biotechnological strategies based on solid state fermentation have been used to enrich cereals with PUFA as a major food source. Under appropriate conditions, lower filamentous fungi were able to transform numerous cereal substrates to products containing various n‐6 and n‐3 PUFAs.
Dietary fat and the risk of having a stroke
Authors: Stanley John C. 
Published: December 2009

AbstractStroke is the third largest cause of death behind coronary heart disease and cancer and the leading cause of long‐term disability in many countries such as the United Kingdom. Stroke has greater effects on mortality and morbidity in women than in men. However, by contrast with coronary heart disease and cancer very little information is available on effects of diet on the risk of having a stroke. Effects of saturated fat on the risk of having a stroke are puzzling as four prospective studies have shown inverse associations implying a protective effect of saturated fat although one large prospective study has shown no association. These findings are not consistent with the Lipid Hypothesis. By contrast the available evidence suggests that oily fish and fish oil protect against having an ischaemic stroke. More research is urgently needed which analyses effects of diet on stroke subtypes and gender separately.