bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polyurethane elastomer: A new material for the visualization of cadaveric blood vessels
Authors: Meyer Eric P. , Beer Gertrude M. , Lang Axel , Manestar Mirjana , Krucker Thomas , Meier Sonja , Mihic‐Probst Daniela , Groscurth Peter 
Published: October 2006

AbstractA multitude of various materials are available for the visualization of cadaveric vessels, ranging from natural materials like gelatin and latex to synthetic materials like silicone rubber or acrylates. To achieve a detailed overview of the vascular architecture in microvascular studies in experimental flap surgery, the injected material should have low viscosity to assure perfusion of even the smallest vessels. In addition, the material ideally should have either no or only minimal shrinkage, and should harden within a reasonable time, but retain sufficient elasticity and resistance to withstand tearing off the delicate vessels during subsequent dissection or casting. Because none of the available injection materials adequately combines these attributes, we evaluated the polyurethane elastomer “PU4ii” in latissimus dorsi muscles as a new material for the visualization of cadaveric vessels in comparison with the frequently used silicone rubber. The dissection of vessels injected with PU4ii proved easy largely because of its exceptional hardness. Even if not visible before dissection, the completely perfused vessels were easily palpated in the surrounding fat or muscle tissue of the microsurgical latissimus dorsi model. Despite the significantly higher hardness of PU4ii over silicone rubber (98 Sh‐A vs. 12 Sh‐A), PU4ii proved enough elasticity (20–25 N/mm2 E modulus) and a high tear resistance (64–68 N/mm vs. 15 N/mm) preventing breakage during dissection even within the smallest vessels. In contrast to silicone rubber (and latex or gelatin), the high corrosion resistance and form stability of PU4ii also allowed building of casts for qualitative examination by scanning electron microscopy and quantitative analysis of the vessel density using micro‐computed tomography with accurate 3D representation. In this study we show that PU4ii has physical characteristics that make it a multi‐purpose material that allows at the same breath an excellent gross visualization of the architecture of cadaveric blood vessels as well as a detailed evaluation of casts by modern microscopic and or radiologic tools. Thus, the new polyurethane elastomer PU4ii is in many respects superior to the widely used silicone rubber and can be strongly recommended as a visualization material for a comprehensive evaluation of cadaveric blood vessels in microsurgery. Clin. Anat. 20:448–454, 2007. © 2006 Wiley‐Liss, Inc.
Synthesis, Solution Structure and Immune Recognition of an Epidermal Growth Factor‐Like Domain from Plasmodium falciparum Merozoite Surface Protein‐1
Authors: James Sonya , Moehle Kerstin , Renard Annabelle , Mueller Markus S. , Vogel Denise , Zurbriggen Rinaldo , Pluschke Gerd , Robinson John A. 
Published: October 2006

AbstractThe Plasmodium falciparum merozoite surface protein‐1 19 kDa fragment (MSP‐119) comprises two closely packed EGF‐like domains (EGF=epidermal growth factor), each stabilized by three disulfide bonds. The native conformation of this protein is important for eliciting P. falciparum growth inhibitory antibodies. Here we show that the N‐terminal EGF domain alone can be chemically synthesized and efficiently refolded to a native‐like state, as shown by its solution structure as determined by NMR spectroscopy. In order to study its immunogenicity, the domain was coupled through its N terminus to a phospholipid and incorporated into reconstituted influenza virus‐like particles (virosomes). When used to immunize mice, the peptide‐loaded virosomes elicited potent humoral immune responses that were shown by Western blots and immunofluorescence assays to cross‐react with native MSP‐1 on the surfaces of P. falciparum blood stage parasites. This opens the way for a medicinal chemistry‐oriented approach to the study and optimization of the antigenicity of the protein as a potential malaria vaccine candidate, whilst exploiting the immunopotentiating properties of influenza virosomes as a delivery vehicle.
Switching between Ligand‐to‐Ligand Charge‐Transfer, Intraligand Charge‐Transfer, and Metal‐to‐Ligand Charge‐Transfer Excited States in Platinum(II) Terpyridyl Acetylide Complexes Induced by pH Change and Metal Ions
Authors: Han Xue , Wu Li‐Zhu , Si Gang , Pan Jie , Yang Qing‐Zheng , Zhang Li‐Ping , Tung Chen‐Ho 
Published: October 2006

AbstractA series of platinum(II) terpyridyl alkynyl complexes, [Pt{4′‐(4‐R1‐C6H4)terpy}(CC‐C6H4‐R2‐4)]ClO4 (terpy = 2,2′:6′,2′′‐terpyridyl; R1 = R2 = N(CH3)2 (1); R1 = N(CH3)2, R2 = N‐[15]monoazacrown‐5 (2); R1 = CH3, R2 = N(CH3)2 (3); R1 = N(CH3)2, R2 = H (4); R1 = CH3, R2 = H (5)), has been synthesized and the photophysical properties of the complexes have been examined through measurement of their UV/Vis absorption spectra, photoluminescence spectra, and transient absorptions. Complex 3 shows a lowest‐energy absorption corresponding to a ligand‐to‐ligand charge‐transfer (LLCT) transition from the acetylide to the terpyridyl ligand, whereas 4 shows an intraligand charge‐transfer (ILCT) transition from the π orbital of the 4′‐phenyl group to the π* orbital of the terpyridyl. Upon protonation of the amino groups in 3 and 4, their lowest‐energy excited states are switched to dπ(Pt)→π*(terpy) metal‐to‐ligand charge‐transfer (MLCT) states. The lowest‐energy absorption for 1 and 2 may be attributed to an LLCT transition from the acetylide to the terpyridyl. Upon addition of an acid to a solution of 1 or 2, the amino group on the acetylide is protonated first, followed by the amino group on the terpyridyl. Thus, the lowest excited state of 1 and 2 can be successively switched from the LLCT state to the ILCT state and then to the MLCT state by controlling the amount of the acid added. Such switches in the excited state are fully reversible upon subsequent addition of a base to the solution. Sequential addition of alkali metal or alkaline earth metal ions and then an acid to a solution of 2 also leads to switching of its lowest excited state from the LLCT state, first to the ILCT state and then to the MLCT state. All of the complexes exhibit a transient absorption of the terpyridyl anion radical, which is present in all of the LLCT, ILCT, and MLCT states. However, the shape of the transient absorption spectrum depends on both the substitution pattern on the terpyridyl moiety and the nature of the excited state.
Ursachen der erhöhten Resistenz von Mikroorganismen in Biofilmen
Authors: Schulte Simone , Flemming Hans‐Curt 
Published: October 2006

AbstractBiofilme stellen die älteste Form des Lebens auf der Erde dar, in der sie durch Selektion über Milliarden Jahre ein enormes Überlebenspotenzial entwickelt haben. Dazu gehört, dass sie wesentlich widerstandsfähiger gegenüber Bioziden sind als in der planktonischen Form in der Wasserphase. Die Gründe für die Resistenz sind vielfältig. Für die Praxis bedeutet dies, dass es schwierig ist, Biofilme vollständig abzutöten, weil immer damit gerechnet werden muss, dass ein kleiner Teil der Population überlebt. Rasche und generelle Lösungen für Biofilm‐Probleme gibt es nicht – es kommt immer auf die jeweiligen Gegebenheiten des zu schützenden Systems an. Daher sind integrative Ansätze entscheidend, bei denen sowohl das Medium, die Materialien, das Design, der Prozess und die Überwachung ineinander greifen. Dann aber lassen sich Biofilm‐Probleme durchaus unter Kontrolle halten.
Kombination von Mikrofiltration und thermischen Verfahren zur Haltbarkeitsverlängerung von Lebensmitteln
Authors: Kaufmann V. , Kulozik U. 
Published: October 2006

AbstractMittels Mikrofiltration lässt sich ein Großteil der im Produkt enthaltenen Mikroorganismen mechanisch abtrennen und damit die Haltbarkeit von Milch verlängern. Um eine möglichst effiziente und selektive Keimretention bei konstantem Flux zu erreichen, sind dabei verschiedene Einflussgrößen (Anlagenkonzeption, Prozessbedingungen) und im Laufe des Filtrationsprozesses auftretende Effekte wie Deckschichtbildung und/oder (Bio)Fouling zu berücksichtigen. Die Kombination von membrantrenntechnischer und thermischer Behandlung ermöglicht eine produktschonende Prozessintensivierung. Neben dem eigentlichen Herstellprozess spielen im Hinblick auf die Qualität und die Stabilität der Milch zudem vor‐ und nachgelagerte Faktoren (Rohmilchbeschaffenheit, Prozesshygiene und Verpackung sowie Lager‐ und Distributionsbedingungen) eine Rolle.
Relationship of presympathetic‐premotor neurons to the serotonergic transmitter system in the rat brainstem
Authors: Kerman Ilan A. , Shabrang Cyrus , Taylor Larry , Akil Huda , Watson Stanley J. 
Published: October 2006

AbstractNumerous physiological conditions and emotionally motivated behaviors require concomitant activation of somatomotor and sympathetic efferents. Using a virally mediated retrograde transsynaptic tract‐tracing approach, we have previously determined locations of presympathetic‐premotor neurons (PSPMNs) in the rat brainstem. These putative dual‐function neurons send projections to somatomotor and sympathetic targets and likely participate in sympatho‐somatomotor integration. A significant portion of these neurons is found within brainstem areas known to contain serotonergic neurons. Thus, we hypothesized that some of the PSPMNs utilize serotonin as their neurotransmitter. To test this hypothesis we first produced an antibody against TPH2, a brain‐specific isoform of tryptophan hydroxylase (serotonin synthetic enzyme). We identified PSPMNs by using recombinant strains of the pseudorabies virus (PRV) for transsynaptic tract‐tracing. PRV‐152, a strain that expresses enhanced green fluorescent protein, was injected into sympathectomized gastrocnemius muscle, while PRV‐BaBlu, which expresses β‐galactosidase, was injected into the adrenal gland in the same animals. Using immunofluorescent methods we determined whether coinfected neurons expressed TPH2. Our findings demonstrate that TPH2‐positive PSPMNs are present at different rostrocaudal levels of the brainstem. Just over half of them are found at the pontomedullary junction within raphe obscurus, raphe magnus, and gigantocellular nucleus pars alpha. These cells may play a role in mediating responses to acute pain stimuli and/or participate in the central control of exercise. Overactivity of these serotonergic sympatho‐somatomotor circuits may also play a role in the pathophysiology of serotonin syndrome. J. Comp. Neurol. 499:882–896, 2006. © 2006 Wiley‐Liss, Inc.
Distinct expression and localization of serine protease HtrA1 in human endometrium and first‐trimester placenta
Authors: Nie Guiying , Hale Kathryn , Li Ying , Manuelpillai Ursula , Wallace Euan M. , Salamonsen Lois A. 
Published: October 2006

AbstractMammalian embryos cannot survive without the placenta. Development of the human placenta requires trophoblast proliferation, differentiation, and invasion as well as highly coordinated modulation of the maternal uterus. HtrA1 is a member of the recently identified mammalian HtrA (high temperature requirement factor A) serine protease family with a high level of expression in the placenta. In this study, we examined whether HtrA1 expression (mRNA and protein) is associated with placental development in the human. HtrA1 is up‐regulated in both endometrial glands and decidual cells during endometrial preparation for embryo implantation and during first‐trimester pregnancy at placentation. HtrA1 expression was also detected in certain trophoblast subtypes during early pregnancy. The villous syncytiotrophoblast and cytotrophoblast showed the strongest expression while the interstitial extravillous trophoblast showed the lowest or no expression of HtrA1. The distinct distribution of HtrA1 at the maternal‐trophoblast interface suggests that HtrA1 may play a role in placental development. Developmental Dynamics 235:3448–3455, 2006. © 2006 Wiley‐Liss, Inc.
New Bis(silyl)cyclopentadienidoniobium and ‐tantalum Complexes:X‐ray Crystal Structures of [NbCp∧Cl4] and [NbCp∧Cl4(CNAr)][Cp∧ = η5‐C5H3(SiClMe2)(SiMe3); Ar = 2,6‐Me2C6H3]
Authors: Gómez Manuel , Gómez‐Sal Pilar , Hernández José Manuel 
Published: October 2006

AbstractThe [bis(silyl)cyclopentadienido]tetrachloroniobium and‐tantalum complexes [MCp∧Cl4] [Cp∧ = η5‐C5H3(SiClMe2)(SiMe3); M = Nb 3, Ta 4] were synthesized by reaction of the pentachlorides MCl5 with C5H3(SiClMe2)(SiMe3)2 (1). Although the Lewis acidity of tetrachloro complexes 3 and 4 is lower than that of the pentahalides, two adducts [M{η5‐C5H3(SiClMe2)(SiMe3)}Cl4(CNAr)] (Ar = 2,6‐Me2C6H3; M = Nb 5, Ta 6) have been isolated by reaction with ArNC. Complexes 3 and 4 react with tert‐butylamine or lithium amides to afford the dichloroimido and amidochloroimido complexes [M{η5‐C5H3(SiClMe2)(SiMe3)}Cl2(NR)] (R = tBu, M = Nb 7, Ta 8; R = Me, M = Nb 9) and [Ta{η5‐C5H3(SiClMe2)(SiMe3)}Cl(NHtBu)(NtBu)] (10), respectively. In addition, 7 and 8 can be prepared by treatment of the pentachlorides with [C5H3(SiMe2NHtBu)(SiMe3)2] (2) by elimination of 1. The tetrachloro compound 3 reacts with four equivalents of tBuNH2 to give the constrained‐geometry derivative [Nb{η5‐C5H3(SiMe2NtBu‐κN)(SiMe3)}Cl(NtBu)] (11), whereas the treatment of toluene solutions of 3 and 4 with H2NCH2CH2NH2 in the presence of triethylamine leads to the trichloro complexes [M{η5‐C5H3(SiMe2NCH2CH2NH2‐κ2N,N)(SiMe3)}Cl3] (M = Nb 12, Ta 13). All the reported complexes were studied by IR and NMR spectroscopy and the molecular structures of complexes 3 and 5 were determined by X‐ray diffraction methods. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Enhanced differentiation and mineralization of human fetal osteoblasts on PDLLA containing Bioglass® composite films in the absence of osteogenic supplements
Authors: Tsigkou O. , Hench L.L. , Boccaccini A.R. , Polak J.M. , Stevens M.M. 
Published: October 2006

AbstractThis study investigates the cellular response of fetal osteoblasts to bioactive resorbable composite films consisting of a poly‐D,L‐lactide (PDLLA) matrix and bioactive glass 45S5 Bioglass® (BG) particles at three different concentrations (0% (PDLLA), 5% (P/BG5), and 40% (P/BG40)). Using scanning electron microscopy (SEM) we observed that cells were less spread and elongated on PDLLA and P/BG5, whereas cells on P/BG40 were elongated but with multiple protrusions spreading over the BG particles. Vinculin immunostaining revealed similar distribution of focal adhesion contacts on all cells independent of substratum, indicating that all materials permitted cell adhesion. However, when differentiation and maturation of fetal osteoblasts was examined, incorporation of 45S5 BG within the PDLLA matrix was found to significantly (p < 0.05) enhance alkaline phosphatase enzymatic activity and osteocalcin protein synthesis compared to tissue culture polystyrene controls and PDLLA alone. Alizarin red staining indicated extracellular matrix mineralization on both P/BG5 and P/BG40, with significantly more bone nodules formed than on PDLLA. Real time RT‐PCR revealed that expression of bone sialoprotein was also affected by the BG containing films compared to controls, whereas expression of Collagen Type I was not influenced. By performing these investigations in the absence of osteogenic factors it appears that the incorporation of BG stimulates osteoblast differentiation and mineralization of the extracellular matrix, demonstrating the osteoinductive capacity of the composite. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
A novel poly(ethylene glycol)–fibrinogen hydrogel for tibial segmental defect repair in a rat model
Authors: Peled Eli , Boss Jochanan , Bejar Jacob , Zinman Chaim , Seliktar Dror 
Published: October 2006

AbstractThe aim of this study is to investigate regeneration in a segmental bone defect using a novel fibrinogen‐based hydrogel material. The use of hydrogels made from poly(ethylene glycol) (PEG) conjugated to fibrinogen for this purpose may be better to conventional fibrin‐based materials as it offers an additional degree of control over the structural characteristics and biodegradation of the material. At the same time, it maintains some of the inherent biofunctionality of the fibrinogen molecule. PEGylated fibrinogen hydrogels with various degrees of proteolytic resistance based on PEG and fibrinogen composition were designed for slow, intermediate, and fast biodegradation. The hydrogels were implanted into 7‐mm segmental rat tibial defects without additional osteoinductive factors with the rationale that the ingrowth matrix will displace the normal fibrin clot while sustaining a similar healing effect for a longer duration. Histological and X‐ray results confirmed that the extent and distribution of newly formed bone in the defect after 5 weeks strongly parallels the biodegradation pattern of the implanted material. When compared to nonunions in animals treated with the fast‐degrading implants and untreated control animals, the rats implanted with the intermediate‐degrading material exhibited osteoneogenesis. This data supports the hypothesis that the perseverance of the PEGylated fibrinogen material can be synchronized with the optimal healing characteristics of a segmental osseous defect and that the consequent sustained release of fibrinogen fragments facilitates the osteogenic response at the injury site. The PEGylated fibrinogen material may, therefore, be a highly efficacious material for promoting the healing of bone defects and especially nonunion fractures. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
A mathematical model for predicting controlled release of bioactive agents from composite fiber structures
Authors: Zilberman Meital , Sofer Moran 
Published: October 2006

AbstractA mathematical model for predicting bioactive agent release profiles from core/shell fiber structures was developed and studied. These new composite fibers, which combine good mechanical properties with desired protein release profiles, are designed for use in tissue regeneration and other biomedical applications. These fibers are composed of an inner dense polymeric core surrounded by a porous bioresorbable shell, which encapsulates the bioactive agent molecules. The model is based on Fick's second law of diffusion, and on two major assumptions: (a) first‐order degradation kinetics of the porous shell, and (b) a nonconstant diffusion coefficient for the bioactive agent, which increases with time because of degradation of the host polymer. Three factors are evaluated and included in this model: a porosity factor, a tortuosity factor, and a polymer concentration factor. Our study indicates that the model correlates well with in vitro release results, exhibiting a mean error of less than 2.2% for most studied cases. In this study, the model was used for predicting protein release profiles from fibers with shells of various initial molecular weights and for predicting the release of proteins with various molecular weights. This new model exhibits a potential for simulating fibrous systems for a wide variety of biomedical applications. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Preparation of nano‐tentacle polypyrrole with pseudo‐molecular template for ATP incorporation
Authors: Xiao Yinghong , Che Jianfei , Li Chang Ming , Sun Chang Q. , Chua Yek T. , Lee Vee S. , Luong John H.T. 
Published: October 2006

AbstractPolypyrrole was electrochemically synthesized onto a gold electrode in the presence of sodiump‐toluenesulfonate (TSNa) as the key dopant. Under the optimal synthesis condition, the surface morphology of PPy/TSNa was tailored and exhibited a nano‐tentacle structure. The resulting rough and fuzzy morphology greatly enhanced the apparent surface area as well as the polymer film conductivity. Adenosine triphosphate (ATP) was then incorporated in the structure by subsequent ion exchanging. This procedure could be envisaged as pseudo‐molecular templating to eliminate several shortcomings associated with physical templating. Fourier transform infrared (FTIR) and ultraviolet‐visible (UV‐vis) spectroscopy were conducted to investigate the incorporation of ATP. The pronounced rough surface of PPy/TSNa provided a higher density of active sites for ATP binding. The resulting PPy/ATP film exhibited a high charged capacity and lower impedance compared to the bare gold electrode. ATP remained stable in the PPy film; however, a negative bias to the electrode stimulated the conducting polymer to release ATP. This concept could serve as a mechanism for drug delivery and biosensing applications. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Transfer of apatite coating from porogens to scaffolds: Uniform apatite coating within porous poly(DL‐lactic‐co‐glycolic acid) scaffold in vitro
Authors: Li Jiashen , Beaussart Audrey , Chen Yun , Mak Arthur F.T. 
Published: October 2006

AbstractStrategies to bone tissue engineering have focused on the use of synthetic or natural degradable materials as scaffolds for cell transplantation to guide bone regeneration. Biocompatibility, biodegradability, biomechanical integrity, and osteoconductivity are important requirements for the scaffold materials. This study explored a new approach of apatite coating to enhance the osteoconductivity of a synthetic degradable poly(DL‐lactic‐co‐glycolic acid) (PLGA) scaffold. The new approach was developed to ensure a relatively uniform apatite coating on the interior pore surfaces deep inside a scaffold, even for a relatively thick scaffold with small pores. Apatite was first coated on the surface of paraffin spheres of the desirable sizes. The paraffin spheres were then molded to form a foam. PLGA/pyridine solution was cast into the interspaces among the paraffin spheres. After the paraffin spheres were dissolved and removed by cyclohexane, PLGA scaffold with controlled pore size, good interconnectivity and high porosity was obtained with apatite left on the pore surface uniformly throughout the whole scaffold. The scaffold and apatite coating were characterized using thermogravimetry analysis, scanning electron microscopy, energy dispersive X‐ray spectroscopy, and X‐ray diffractometry. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Small complete caps inPG(N,q),qeven
Authors: Giulietti Massimo 
Published: October 2006

AbstractA new family of small complete caps inPG(N,q),qeven, is constructed. Apart from small values of eitherNorq, it provides an improvement on the currently known upper bounds on the size of the smallest complete cap inPG(N,q): forNeven, the leading term$q^{{N}\over{2}}$is replaced by$\alpha q^{{N}\over{2}}$with$\alpha \le {{1}\over{2}}$, forNodd the leading term$3q^{{N-1}\over{2}}$is replaced by$\beta q^{{N-1}\over{2}}$with$\beta \le {{5}\over{2}}$. © 2006 Wiley Periodicals, Inc. J Combin Designs 15: 420–436, 2007
There is no 2‐(22, 8, 4) block design
Authors: Bilous Richard , Lam Clement W. H. , Thiel Larry H. , Li (Ben) P. C. , van Rees G. H. John , Radziszowski Stanisław P. , Holzmann Wolfgang H. , Kharaghani Hadi 
Published: October 2006

AbstractIn this article, we show that a 2‐(22,8,4) design does not exist. This result was obtained by a computer search. © 2006 Wiley Periodicals, Inc. J Combin Designs 15: 262–267, 2007