bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protein electrostatic self‐assembly on poly(DL‐lactide) scaffold to promote osteoblast growth
Authors: Zhu Huiguang , Ji Jian , Barbosa M. A. , Shen Jiacong 
Published: May 2004

AbstractThe development of protein coating on 3D biodegradable scaffold based on electrostatic self‐assembly (ESA) to promote osteoblast growth is reported. Poly (ethylenimine) (PEI) was employed to obtain a stable positively charged surface on poly(DL‐lactide) (PDL‐LA) substrate. An extracellular‐matrix (ECM)‐like biomacromolecule, gelatin, was chosen as the polyelectrolyte to deposit on the activated PDL‐LA substrate via ESA technique. Osteoblast (MC3T3) was then cultured on unmodified and gelatin‐modified PDL‐LA scaffolds. Osteoblast testing regarding total intracellular protein content, total DNA content, cell activity, and cell morphology on the ECM‐like multilayer‐modified PDL‐LA scaffold showed that osteoblast growth was promoted. It will be easy to replace the gelatin with osteoinductive proteins or other polyelectrolytes to promote specific osteoblast functions. In comparison with conventional coating methods, polyelectrolyte multilayers are easy and stable to prepare. They may be a good choice for the surface modification of complex biomedical devices, especially for the 3D tissue‐engineering scaffold. These very flexible systems allow broad medical applications for drug delivery and tissue engineering. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 71B: 159–165, 2004
Protease nexin‐1: A cellular serpin down‐regulated by thrombin in rat aortic smooth muscle cells
Authors: Richard Benjamin , Arocas Véronique , Guillin Marie‐Claude , Michel Jean‐Baptiste , Jandrot‐Perrus Martine , Bouton Marie‐Christine 
Published: June 2004

AbstractProtease nexin‐1 (PN‐1), a potent inhibitor of serine proteases, is present in vascular cells and forms complexes with thrombin, plasminogen activators, and plasmin. We examined the effect of thrombin on PN‐1 expression by rat aortic smooth muscle cells (RASMCs). PN‐1 expression was determined by measuring protein and mRNA levels, using respectively immunoblotting and semi‐quantitative reverse transcriptase polymerase chain reaction (PCR). Thrombin down‐regulated PN‐1 expression in a dose‐ and time‐dependent manner. This effect was mediated via the interaction of thrombin with its receptor protease activated receptor (PAR‐1) since the peptide thrombin receptor activating peptide (TRAP) reduced PN‐1 expression. PN‐1 secreted by smooth muscle cells remained essentially associated to cell‐surface glycosaminoglycans and was released from the cell surface by heparin. A lower amount of PN‐1 was released by heparin from TRAP‐stimulated versus unstimulated cells and correlated with a decreased capacity to inhibit thrombin. In addition, the ability to generate peri‐cellular plasmin was increased in cells with a low PN‐1 expression. Pre‐treatment of smooth muscle cells with cycloheximide abolished the reduction of PN‐1 expression by thrombin. Furthermore, conditioned media from thrombin‐treated cells reproduced the effect of thrombin, suggesting that thrombin acted via the induction of auto/paracrine mediator(s). We observed that fibroblast growth factor‐2 (FGF‐2)‐neutralizing antibodies abolished thrombin effect whereas FGF‐2 reproduced it, indicating that FGF‐2 is one of the involved mediator. Together, these results indicate that (i) PN‐1 modulates the activity of endogenous and exogenous serine proteases in RASMCs, (ii) thrombin down‐regulates PN‐1 expression and thus may increase its own activity on cells. J. Cell. Physiol. 201: 138–145, 2004. © 2004 Wiley‐Liss, Inc.
A new Holocene relative sea‐level curve for Terra Nova Bay, Victoria Land, Antarctica
Authors: Baroni Carlo , Hall Brenda L. 
Published: June 2004

AbstractMore than 100 radiocarbon dates of penguin guano and remains, shells and seal skin afford ages for raised beaches adjacent to Terra Nova Bay, Antarctica. These dates permit construction of a new relative sea‐level curve that bears on the timing of deglaciation. Recession of the Ross Sea ice‐sheet grounding line from Terra Nova Bay occurred no earlier than 7200 14C yr (8000 cal. yr) BP. Retreat along the Victoria Land coast may have been rapid, possibly contributing to eustatic sea‐level rise centred at ca. 7600 cal. yr BP. The presence of a significant amount of ice remaining in the Ross Sea Embayment in Holocene time lessens the chance that Antarctica contributed significantly to meltwater pulse 1A several thousand years earlier. Copyright © 2004 John Wiley & Sons, Ltd.
Temporal changes in Holocene δ18O records from the northwest and central North Iceland Shelf
Authors: Castañeda Isla S. , Smith L. Micaela , Kristjánsdóttir Gréta Björk , Andrews John T. 
Published: June 2004

AbstractThe region of north Iceland is highly sensitive climatically owing to its location with respect to atmospheric and oceanographic fronts. In this study we present total carbonate and δ18O records of benthic and planktic Foraminifera from nine sediment cores from the North Iceland Shelf. The results of this work indicate that the deglaciation of the Vestfirdir Peninsula was completed by 10 200 cal. yr BP. The 8200 cal. yr BP cold event is present only as a minor isotopic event, and seems not to have had much of a cooling effect on the bottom waters of the northwest Iceland shelf. The Holocene maximum warmth, attributed to a stronger North Icelandic Irminger Current, occurred between ca. 7800 and 6200 cal. yr BP. Over the past 4500 cal. yr BP a general cooling trend has occurred on the North Iceland Shelf, and superimposed on this overall cooling trend are a number of oscillations between periods when relatively warmer and cooler waters occupied the shelf. Relatively cooler waters were present at 4200–4000 cal. yr BP, 3200–2900 cal. yr BP, 2500–2350 cal. yr BP and 600–200 cal. yr BP, whereas relatively warmer waters were present on the shelf at 3750–3450 cal. yr BP, 2800–2600 cal. yr BP and 1700–1000 cal. yr BP. Copyright © 2004 John Wiley & Sons, Ltd.
Why cross‐cultural knowledge transfer is a form of translation in more ways than you think
Authors: Holden Nigel J. , Von Kortzfleisch Harald F. O. 
Published: June 2004

AbstractKnowledge transfer is often likened to acts of translation. It is argued that translation is a very robust analogue of knowledge transfer and that theory provides insight into cross‐cultural sharing processes. Three issues which affect the quality of translation and, hence, knowledge transfer are highlighted: ambiguity, interference (intrusion from one's own cultural background) and lack of equivalence. Other terms from translation science, which can serve as a useful reference for knowledge management experts, are discussed: translation as a networking activity, process and end‐product quality, levels of accuracy and constraints on the production of good translations. A new concept is introduced to the knowledge management community; namely convertibility, which refers to the perceived utility of a knowledge source and the availability of domain experts to reveal its import to final users. Two models representing knowledge transfer as translation are presented, the second of which incorporates Nonaka's SECI model. Copyright © 2004 John Wiley & Sons, Ltd.
Fuzzy cognitive maps as a back end to knowledge‐based systems in geographically dispersed financial organizations
Authors: Xirogiannis George , Glykas Michael , Staikouras Christos 
Published: June 2004

AbstractThis paper addresses the problem of designing a knowledge management methodology tool to act as a decision support mechanism for geographically dispersed financial enterprises. The underlying research addresses the problem of information capture and representation in financial institutions in order to provide an implementation of the virtuous cycle of knowledge flow. The proposed methodology tool utilizes the fuzzy causal characteristics of Fuzzy Cognitive Maps (FCMs) to generate a hierarchical and dynamic network of interconnected financial performance concepts. By using FCMs, the proposed mechanism simulates the operational efficiency of distributed organizational models with imprecise relationships and quantifies the impact of the geographically dispersed activities to the overall business model. Generic adaptive maps that supplement the decision‐making process present a roadmap for integrating hierarchical FCMs into the business model of typical financial sector enterprises. Copyright © 2004 John Wiley & Sons, Ltd.
Direct and Reverse ATRP of MMA in Aqueous Dispersed Medium in the Presence of a Bipyridine‐Functionalized Block Copolymer Support
Authors: Kotre Thomas , Nuyken Oskar , Weberskirch Ralf 
Published: June 2004

AbstractSummary: In a recent communication (Macromol. Rapid Commun. 2002, 23, 871), we reported the synthesis of a bipyridine containing amphiphilic polymer and its usage as macroligand in the atom transfer radical polymerization (ATRP) of MMA in aqueous dispersed medium. Investigations on the mechanism and locus of nucleation by transmission electron microscopy (TEM) studies herein of latex particles prepared by direct ATRP using oil‐soluble ethyl 2‐bromoisobutyrate as initiator revealed a broad particle size distribution between 250 nm and 1 μm, suggesting two nucleation sites, micelles and monomer droplets. By using the water‐soluble initiator 2,2′‐azoisobutyramidine‐dihydrochloride (V‐50) reverse ATRP experiments were conducted at 90 °C. Kinetic measurements showed a sigmoidal slope of monomer conversion versus time as a first indication for an emulsion‐like process. Controlled polymerization behavior was achieved at a ratio of radicals versus Cu(II) deactivator of 1:8. TEM measurements of polymer latex particles obtained by reverse ATRP revealed particle sizes between 100 and 400 nm. Residual copper content of eight PMMA samples prepared by direct and reverse ATRP was determined to be 0.01–0.03 wt.‐% (theoretical 0.73 wt.‐%) and indicated that on average 96–99% of all copper used in a polymerization experiment can be removed from the polymer latex particles by a simple precipitation/washing step.Direct and reverse ATRP experiments of MMA in aqueous media in the presence of an amphiphilic, water‐soluble block copolymer with pendent bipyridine units.magnified imageDirect and reverse ATRP experiments of MMA in aqueous media in the presence of an amphiphilic, water‐soluble block copolymer with pendent bipyridine units.
Fine Structures in the Spherulites of Regioregular Poly(3‐dodecylthiophene)
Authors: Wang Wei , Toh Kee Chua , Tjiu Chauhari Wuiwui 
Published: June 2004

AbstractSummary: In this work, we employed various techniques to cooperatively characterize the crystalline structure and morphology of a regioregular poly(3‐dodecylthiophene). We observed the spherulites in casting films first by polarized light microscopy and then further studied the fine structures within the spherulites by scanning and transmission electron microscopy. These studies showed that the stripe‐like structures with a width of ≈20 nm and a length of 100–500 nm are the basic building blocks of the spherulites. The small‐angle X‐ray scattering and wide‐angle X‐ray diffraction studies further confirm the existence of such the structures. Considering the stiff and unfolding feature of the macromolecules, we believe that the stiff macromolecules may adopt a special way to form the fine structure: the orientation of stiff macromolecules parallel to the longitudinal direction of the stripes without any chain folding.
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New Types of Telechelic Polyisobutylenes, 1
Authors: Nagy Miklós , Orosz László , Kéki Sándor , Deák György , Herczegh Pál , Zsuga Miklós 
Published: May 2004

AbstractSummary: A new, simple, and effective synthetic method for the preparation of glucose‐terminated polyisobutylenes starting from the corresponding hydroxyl‐terminated polymers is reported. Detailed NMR and matrix‐assisted laser desorption/ionization mass spectrometric (MALDI‐TOF MS) investigations showed the exclusive presence of bis(glucopyranosyl) polyisobutylene. Dynamic light scattering (DLS) investigations of this polymer in solution in both tetrahydrofuran and water showed that microphase separation takes place by the formation of micelles and/or vesicles.Representative structure of the glucose‐terminated polyisobutylenes synthesized here.imageRepresentative structure of the glucose‐terminated polyisobutylenes synthesized here.
An Attenuated Total Reflection FT‐IR Spectroscopic Study of Polyamide 6/Clay Nanocomposite Fibers
Authors: Chen Guangming , Shen Deyan , Feng Meng , Yang Mingshu 
Published: May 2004

AbstractSummary: An attenuated total reflection FT‐IR spectroscopic study of the hydrogen bonding, molecular orientation, and crystalline phase transitions in polyamide 6 (PA6)/clay nanocomposite (PA6CN) fibers is proposed. The nanoscale dispersed clay layers lowered the degree of order of hydrogen bonding, affected little the hydrogen bonding strength, and increased the degree of orientation of both γ crystalline and overall domains. A partial γ to α phase transition appeared with time.Schematic representation of the attenuated total reflection FT‐IR dichroism measurements.imageSchematic representation of the attenuated total reflection FT‐IR dichroism measurements.
Cover Picture: Macromol. Rapid Commun. 11/2004
Authors: Iwata Tadahisa , Aoyagi Yoshihiro , Fujita Masahiro , Yamane Hideki , Doi Yoshiharu , Suzuki Yoshio , Takeuchi Akihisa , Uesugi Kentaro 
Published: May 2004

Cover: Biodegradable strong poly[(R)‐3‐hydroxybutyrate] (P(3HB)) fibers with a tensile strength of 1.32 GPa and Young's modulus of 18.1 GPa were processed from ultra‐high‐molecular‐weight P(3HB) by cold‐drawing and two‐step‐drawing procedures. The molecular and higher‐ordered structure in the P(3HB) mono‐filament were analyzed by a micro‐beam X‐ray diffraction by using a Fresnel Zone Plate technique in synchrotron radiation and linearly scanned perpendicular to the fiber axis. It was revealed that P(3HB) fiber has a new core‐sheath structure with two types of molecular conformations: one is a 21 helix conformation in the sheath region and the other is a planar zigzag conformation in the core region.Further details can be found in the Communication by T. Iwata,* Y. Aoyagi, M. Fujita, H. Yamane, Y. Doi, Y. Suzuki, A. Takeuchi, and K. Uesugi on page 1100.
Estrogen‐dependent regulation of ornithine decarboxylase in breast cancer cells through activation of nongenomic cAMP‐dependent pathways
Authors: Qin Chunhua , Samudio Ismael , Ngwenya Sharon , Safe Stephen 
Published: May 2004

Abstract17β‐Estradiol (E2) induces ornithine decarboxylase (ODC) activity in several E2‐responsive tissues/cells, and this study investigated the mechanism of hormone‐induced transactivation in MCF‐7 human breast cancer cells. E2‐induced reporter gene (luciferase) activity in MCF‐7 cells transfected with a construct (pODC1) containing the −164 to +29 region of the human ODC gene promoter linked to bacterial luciferase. This promoter sequence contains GC‐rich Sp1 binding sites, CAAT, LSF, cAMP response element (CRE), and TATA motifs. Deletion and mutational analysis of the ODC promoter showed that both CAAT and LSF sites were required for hormone‐induced transactivation. Gel mobility shift and DNA footprinting assays indicated that NFYA and LSF bound the CAAT and LSF motifs, respectively, and GAL4‐NFYA/GAL4‐LSF chimeras were also activated by E2, 8‐bromo‐cAMP, and protein kinase A (PKA) expression plasmid. However, E2‐induced transactivation of GAL4‐NFYA and GAL4‐LSF was blocked by the PKA inhibitor SQ22356 indicating that the mechanism of ODC induction by E2 involves upregulation of cAMP/PKA through nongenomic pathways of estrogen action. © 2004 Wiley‐Liss, Inc.
Effects of polyunsaturated fatty acids on prostaglandin synthesis and cyclooxygenase‐mediated DNA adduct formation by heterocyclic aromatic amines in human adenocarcinoma colon cells
Authors: Moonen H.J.J. , Dommels Y.E.M. , van Zwam M. , van Herwijnen M.H.M. , Kleinjans J.C.S. , Alink G.M. , de Kok T.M.C.M. 
Published: May 2004

AbstractDietary heterocyclic aromatic amines (HCA) and polyunsaturated fatty acids (PUFA) are both believed to play a role in colon carcinogenesis, and are both substrate for the enzyme cyclooxygenase (COX). In HCA‐7 cells, highly expressing isoform COX‐2, we investigated the effects of PUFA on prostaglandin synthesis and DNA adduct formation by the HCA 2‐amino‐1‐methyl‐6‐phenylimidazo[4,5‐b]pyridine (PhIP) and 2‐amino‐3‐methylimidazo[4,5‐f]quinoline (IQ). Furthermore, we studied the role of COX, COX‐2 in particular, and cytochrome P4501A2 (CYP1A2) by using the enzyme inhibitors indomethacin (IM), NS‐398, and phenethyl isothiocyanate (PEITC), respectively. COX‐mediated formation of prostaglandin E2 (PGE2) from linoleic acid (LA) showed that HCA‐7 cells can convert LA into arachidonic acid (AA). Alternatively, eicosapentaenoic acid (EPA) was found to compete with AA for COX. Strongly decreased PGE2 levels by addition of IM demonstrated involvement of COX in PUFA metabolism. Both IM and NS‐398 inhibited adduct formation by HCA to nearly the same extent, indicating involvement of COX‐2 rather than COX‐1, while CYP1A2 activity in HCA‐7 cells was demonstrated by addition of PEITC. Overall, inhibiting effects were stronger for PhIP than for IQ. HCA‐DNA adduct formation was stimulated by addition of PUFA, although high PUFA concentrations partly reduced this stimulating effect. Finally, similar effects for n‐3 and n‐6 fatty acids suggested that adduct formation may not be the crucial mechanism behind the differential effects of PUFA on colon carcinogenesis that have been described. These results show that COX, and COX‐2 in particular, can play a substantial role in HCA activation, especially in extrahepatic tissues like the colon. Furthermore, the obvious interactions between PUFA and HCA in COX‐2 expressing cancer cells may be important in modulating colorectal cancer risk. © 2004 Wiley‐Liss, Inc.
Non‐isothermal crystallization kinetics of polyamide 1010/montmorillonite nanocomposite
Authors: Liu Zengjun , Yan Deyue 
Published: June 2004

AbstractThe non‐isothermal crystallization kinetics of pure polyamide 1010 (PA1010) and PA1010/montmorillonite nanocomposite (PA1010/MMT) was investigated by differential scanning calorimetry (DSC) at various cooling rates. The Avrami analysis modified by Jeziorny and a new method developed by Mo can describe the non‐isothermal crystallization process of PA1010 and PA1010/MMT nanocomposite very well. The difference in the value of exponent n between PA1010 and PA1010/MMT nanocomposite suggests that the nano‐size montmorillonite layers act as nucleation agents of PA1010. The values of half‐time of crystallization and crystallization rate coefficient (CRC) show that the crystallization rate of PA1010/MMT nanocomposite is faster than that of PA1010 at a given cooling rate. Polym. Eng. Sci. 44:861–867, 2004. © 2004 Society of Plastics Engineers.
Cure characteristics, mechanical properties, and morphological studies of linoleum flour‐filled NBR compounds
Authors: Biagiotti J. , Iannoni A. , Lopez‐Manchado M. A. , Kenny J. M. 
Published: June 2004

AbstractThe effects of the content and size of the filler on the curing characteristics and mechanical properties of linoleum flour‐reinforced acrylonitrile‐butadiene rubber (NBR) composites are analyzed. The linoleum flour was obtained from wastes of linoleum production. The effects of this filler are compared with those of two other kinds of lignocellulosic fillers. Four filler percentages (10, 20, 30 and 40 phr) were added to the rubber. The morphology of the fillers was studied and then related to the curing and mechanical characteristics of the studied compounds. The results indicate that all the fillers behave as vulcanizing agents, accelerating the vulcanization process, which is reflected in a significant decrease of the optimum cure time. In this case, linoleum is the most effective one; however, it produces lower mechanical properties than the other two systems. The results obtained together with the positive environmental impact in the recycling of production wastes would justify the use of linoleum flour in rubber technology. Polym. Eng. Sci. 44:909–916, 2004. © 2004 Society of Plastics Engineers.
Optimal process conditions of shrinkage and warpage of thin‐wall parts
Authors: Liao S. J. , Chang D. Y. , Chen H. J. , Tsou L. S. , Ho J. R. , Yau H. T. , Hsieh W. H. , Wang James T. , Su Y. C. 
Published: June 2004

AbstractOptimal process conditions of thin‐wall injection molding of a cellular phone cover were investigated with the consideration of interaction effects between process parameters. L27experimental tests based on Taguchi's method were performed, and then Cyclone Scanner, PolyCAD and PolyWorks were used to measure the shrinkage and warpage of the thin‐wall injected parts to determine the optimal process conditions. Based on the results of the analysis of variables and the F‐test, interaction effects for each observed factor were determined. The results indicated that the packing pressure was the most important process parameter affecting the shrinkage and warpage of the thin‐wall part. The optimal process conditions were different for the shrinkage and the warpage. This was because during the injection process, the mechanisms affecting shrinkage or warpage were different. Compared with the results obtained with simplified thin‐wall parts in the literature, it was found that the geometry of a real commercial part did affect the optimal process conditions and the order of influence of process parameters. The optimal process conditions determined by Taguchi's method for reducing the shrinkage and warpage were verified experimentally in this work. Polym. Eng. Sci. 44:917–928, 2004. © 2004 Society of Plastics Engineers.
Interlayer adhesion of coextruded films: Effect of biaxial stretching
Authors: Zhou Hongyi 
Published: June 2004

AbstractIn order to understand the effect of thermoforming on the interlayer adhesion of coextruded films, a peel test was performed for coextruded films after being stretched. To simulate the non‐uniaxial stretching nature of actual thermoforming processes, planar stretching and biaxial stretching were applied to the coextruded films prior to the peel test. Both the planar stretching and biaxial stretching were performed at an optimum thermoforming temperature under well‐controlled stretch rates to a predetermined stretch ratio. It was found that there was a significant amount of reduction of interlayer adhesion due to stretching. Furthermore, the loss of interlayer adhesion at the optimum thermoforming temperature was linearly related to thickness drawdown as a result of stretching regardless of stretching modes. Therefore, it is suggested that the effect of thermoforming on interlayer adhesion of coextruded films can be easily estimated from the thickness distribution of thermoformed parts. Polym. Eng. Sci. 44:948–954, 2004. © 2004 Society of Plastics Engineers.