bluuebunny/crossref_metadata_2025 huggingface dataset:
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

Protease 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

More 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

The 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

Knowledge 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

This 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

Summary: 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.

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Direct 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

Summary: 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

Summary: 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.

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Representative 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

Summary: 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.

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Schematic 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

17β‐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

Dietary 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

The 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

The 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

Optimal 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

In 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.
Thickness uniformity of HDPE blown film: Relation to rheological properties and density
Authors: Higuchi Hiroyuki , Fujikawa Shinjiro , Sato Mikio , Koyama Kiyohito
Published: June 2004

Previous work has elucidated that the wall slip velocity and viscosity of polymer melts influence the thickness uniformity of blown film. The present study investigates the effects of the stress dependence of wall slip, the shear thinning and the density on the uniformity. We have prepared high‐density polyethylenes with a variety of molecular weight distributions, which have different rheological properties. Examination of the thickness uniformity of their blown film has shown that the uniformity is correlated with wall slip velocity, the stress dependence of the velocity, melt viscosity, shear thinning and density; the coefficient of the correlation is determined to be 0.990. The reason why the stress dependence of wall slip and the shear thinning affect the uniformity is explained in terms of polymer melt flow behavior in a die, while the effect of density is interpreted considering bubble fluctuation in the blow‐up process. Polym. Eng. Sci. 44:965–972, 2004. © 2004 Society of Plastics Engineers.
Proteomic characterization of herbicide safener‐induced proteins in the coleoptile of Triticum tauschii seedlings
Authors: Zhang Qin , Riechers Dean E.
Published: June 2004

Proteomic methods such as two‐dimensional gel electrophoresis and liquid chromatography tandem mass spectrometry, as well as immunoblotting, were used to identify herbicide safener‐induced proteins in the coleoptile of Triticum tauschii, a diploid wheat containing the D genome also found in the cultivated, hexaploid wheat Triticum aestivum. The herbicide safener fluxofenim dramatically increased protein abundance in the molecular weight (Mr) range of 24 to 30 kDa, as well as a few higher Mr proteins, in the coleoptile of T. tauschii seedlings. In total, twenty proteins were identified in this study. Eleven proteins were highly safener induced and only weakly expressed in the control; seven proteins were new safener induced proteins that were not detected in the control. Two other proteins were constitutively expressed in both the control and safener‐treated coleoptiles. Among the eighteen inducible proteins, fifteen were glutathione S‐transferase (GST) subunits that fall into three subclasses: eight proteins were from the tau subclass, six proteins were from the phi subclass, and one protein was from the lambda class. Another three safener inducible proteins showed homology to the aldo/keto reductase family and with proteins that have roles in glycolysis and the Krebs cycle. Two constitutively expressed proteins were identified, one having highest homology to the dehydroascorbate reductase subclass of GSTs and one with an ascorbate peroxidase. Immunoblot analyses, using two different antisera raised against the same GST protein but differing in their specificity, were used to further characterize the GST proteins expressed in response to safener treatment. Results from immunoblotting, combined with mass spectral analysis, showed that post‐translational modification of GST proteins in control and safener‐treated coleoptiles may occur.
Proteomic analysis of a ferric uptake regulator mutant of Helicobacter pylori: Regulation of Helicobacter pylori gene expression by ferric uptake regulator and iron
Authors: Lee Hyang Woo , Choe Yon Ho , Kim Dae Kyong , Jung Sung Yun , Lee Na Gyong
Published: June 2004

The ferric uptake regulator (Fur) protein is a Fe2+‐dependent transcriptional repressor that binds to the Fur‐box of bacterial promoters and down‐regulates gene expression. In this study, to investigate global gene regulation by Fur in response to iron in Helicobacter pylori, a causative agent of human gastric diseases, we compared the proteome profiles of the H. pylori strain 26695 and its isogenic fur mutant grown under iron‐rich and iron‐depleted conditions. In total, 93 protein spots were found to be up‐ or down‐regulated by more than 2‐fold by either a fur mutation or iron‐depletion. From these, 39 spots were identified by matrix‐assisted laser desorption/ionization time of flight analysis to be 29 different proteins of diverse functions, including energy metabolism, transcription and translation, detoxification, biosynthesis of amino acids and nucleotides and production of the cell envelope. Expression of six proteins was found to be higher in the fur mutant than in the wild‐type bacteria, indicating Fur‐mediated repression. Eleven proteins were activated by Fur; five responded to iron and the others were not iron‐responsive. The remaining 12 proteins were not under Fur‐regulation but responded to iron in a positive or negative manner. Seven different types of gene regulation via Fur and iron were identified. These findings demonstrate that the H. pylori Fur protein functions as a classical transcriptional repressor but can also function as an activator, providing evidence for the presence of Fur‐mediated positive regulation in H. pylori.
Toughness enhancements in poly(methyl methacrylate) by addition of oriented multiwall carbon nanotubes
Authors: Gorga Russell E. , Cohen Robert E.
Published: June 2004

The mechanical properties of multiwall carbon nanotube (MWNT)/poly(methyl methacrylate) (PMMA) nanocomposites were studied as a function of nanotube orientation, length, concentration, and type. Orientation and dispersion were assessed by electron microscopy. A processing parameter study revealed the robust nature of fabricating nanotube/PMMA nanocomposites. An optimal set of extrusion conditions was found for minimizing the aggregate size in single‐wall carbon nanotube (SWNT)/PMMA nanocomposites; this set was also used for the fabrication of the MWNT/PMMA composites. Good dispersion was achieved for MWNTs in PMMA at 0.1–10 wt % loading levels (with the best dispersions at the lower loading levels). The orientation of MWNTs in PMMA proved to be the only way to substantially toughen the nanocomposite. A level of 1 wt % MWNTs in PMMA (oriented nanocomposite) exhibited the largest increase in tensile toughness with a 170% improvement over oriented PMMA. Increases in the modulus and yield strength were not nearly as pronounced (and occurred only at the highest loading of MWNTs, which was 10 wt %) with increases of 38 and 25%, respectively. A failure mechanism was proposed in which orientation of the MWNTs (normal to the direction of craze propagation and crack development) enabled them to toughen the brittle PMMA by bridging cracks that developed (via craze precursors) during the tensile test. None of the nanotube/PMMA composites showed mechanical properties close to the values expected from simple rule of mixture and orientation considerations. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2690–2702, 2004
P704P, P712P, and P775P: A genomic cluster of prostate‐specific genes
Authors: Stolk John A. , Jiang Yuqiu , Day Craig H. , Klee Jennifer I. , Zhang Xinqun , Dillon Davin C. , Houghton Raymond L. , Harlan Dianne , Reed Steven G. , Xu Jiangchun
Published: May 2004

BACKGROUND

Discovery of prostate cancer‐ and tissue‐specific genes will lead to an increased understanding of the molecular events associated with the malignant transformation and tumorigenesis of prostate cells. Such understanding will likely result in the development of promising new markers for screening, diagnosis, and prognosis, as well as potential therapeutic approaches for combating this disease.

METHODS

A PCR‐based subtraction method was combined with a high‐throughput microarray screening approach to identify prostate tissue‐ and/or cancer‐specific genes. Northern blot and quantitative real‐time PCR were used to confirm prostate specificity. Bioinformatics analysis was performed to determine gene localization and to identify the open reading frame of novel genes.

RESULTS

Three novel cDNA clones, P704P, P712P, and P775P, were identified and characterized to be specific for normal and malignant prostate tissues. Furthermore, P712P mRNA expression was found to be androgen responsive in LNCaP cells. Sequences for all three cDNAs were localized to an 80 kb genomic region on chromosome 22. Attempts to identify full‐length transcripts did not reveal any apparent open reading frames, indicating that P704P, P712P, and P775P may belong to a novel class of transcripts with specific patterns of gene expression that do not code for translated proteins.

CONCLUSIONS

A genomic cluster of prostate‐specific genes with no apparent open reading frame has been discovered using a high‐throughput approach combining subtraction with microarray. This may represent an important genomic region having possible connections to prostate biology with potential applications in prostate diagnostics and therapy. © 2004 Wiley‐Liss, Inc.
RETRACTED: Interleukin‐6 protects LNCaP cells from apoptosis induced by androgen deprivation through the Stat3 pathway
Authors: Lee Soo Ok , Lou Wei , Johnson Candace S. , Trump Donald L. , Gao Allen C.
Published: May 2004

BACKGROUND

Elevated expression of interleukin‐6 (IL‐6) is implicated in the progression of hormone refractory prostate cancer. Previous studies demonstrated that IL‐6 promotes androgen‐independent growth of prostate cancer cells. In this study, the effect of IL‐6 on apoptosis induced by androgen deprivation was investigated.

METHODS

The effect of IL‐6 on apoptosis induced by androgen deprivation in LNCaP cells was examined by cell death ELISA and Western blot using cleaved poly (ADP‐ribose) polymerase (PARP) and caspase‐9, as well as Bcl‐xL and phosphorylated Bad. The Stat3 in IL‐6‐mediated anti‐apoptosis in prostate cancer cells was examined using either dominant‐negative or constitutively activated Stat3 mutants.

RESULTS

Overexpression of IL‐6 renders androgen sensitive LNCaP human prostate cancer cells more resistant to apoptosis induced by androgen deprivation. LNCaP cells undergo apoptosis after 72 hr of androgen deprivation, an outcome is largely absent in clones overexpressing IL‐6 as measured by cell death ELISA and chromatin degradation assays. IL‐6 over‐expressing cells resulted in a significant decrease in the expression of cleaved PARP and cleaved caspase‐9 as well as an increase in the expression of Bcl‐xL and phosphorylated Bad. Addition of IL‐6 antibody completely abolished the anti‐apoptotic activity of IL‐6. This protective effect of IL‐6 was reversed by the expression of a dominant‐negative Stat3 mutant, Stat3F. Furthermore, ectopic expression of a constitutively active Stat3 antagonized androgen deprivation‐induced cell death of LNCaP cells.

CONCLUSION

These results indicate that IL‐6 protects androgen sensitive LNCaP cells from apoptosis induced by androgen deprivation, and Stat3 activation play an important role in IL‐6‐mediated anti‐apoptosis in prostate cancer cells. © 2004 Wiley‐Liss, Inc.
The Combinatorial Synthesis of Purine, Pyrimidine and Triazine‐based Libraries
Authors: Bork Jacqueline T. , Lee Jae Wook , Chang Young‐Tae
Published: June 2004

With the advent of combinatorial chemistry, heterocyclic scaffolds can be efficiently used for the generation of large member libraries. Due to the pressing need for such compound libraries, unique synthesis reactions and techniques have been developed to expedite and further improve the process. Present review article summarizes synthetic strategies for the construction of purine, pyrimidine and triazine libraries in both solution and solid phase syntheses. Typical strategy includes the nucleophilc aromatic substitution, such as amination. Also, metal‐mediated synthesis has been used as a driving tool in expanding the diversity of the libraries. Demonstrated biological properties of these libraries, as a rich source of bioactivities, are also highlighted.
2D‐ and 3D‐QSAR Models of Interaction between Flavor Compounds and beta‐Lactoglobulin Using Catalyst and Cerius2
Authors: Tromelin Anne , Guichard Elisabeth
Published: June 2004

The present paper describes an application of Catalyst to three aroma sets (35, 24 and 21 compounds respectively) to generate activities‐based alignments, using the best significant generated hypotheses. The obtained Catalyst models confirmed the existence of at least two binding sites on the BLG.
High‐performance liquid chromatography/inductively coupled plasma mass spectrometry and tandem mass spectrometry for the detection of carbon‐containing compounds
Authors: Smith Christopher , Jensen Berit Packert , Wilson Ian D. , Abou‐Shakra Fadi , Crowther David
Published: June 2004

High‐performance liquid chromatography (HPLC) combined with inductively coupled plasma mass spectrometry (ICPMS) has been studied as a means for the detection of carbon to provide a ‘universal’ method for detecting organic compounds in chromatographic eluents. Carbon is particularly difficult to ionise and the amount of carbon present in normal chromatographic systems leads to high backgrounds, making detection a challenge. Novel separation approaches were therefore employed, using either entirely aqueous eluents (at temperatures of 60 and 160°C, dependent on the column used) to eliminate the organic modifier completely, or isotopically enriched solvents. For the aqueous eluents, detection limits for sulphanilamide were found to be 2.26 μg, corresponding to 1.13 μmol (0.47 μmol of carbon), injected on a conventional 4.6 mm i.d. column. The use of a narrow bore column with highly isotopically enriched 12C‐methanol (99.95 atom%) as organic modifier for the mobile phase enabled the detection of 86 μmol for 13C‐triple‐labelled caffeine and 79 μmol for 13C‐double‐labelled phenacetin. The sensitive detection of 12C‐compounds with 13C‐enriched methanol as organic modifier proved impractical due to a lower level of isotopic enrichment (99 atom%) of this solvent, with the residual 12C‐methanol resulting in significant interference. Copyright © 2004 John Wiley & Sons, Ltd.
High‐performance liquid chromatography with electrospray ionisation mass spectrometry and diode array detection in the identification and quantification of the degradation products of calix[4]arene crown‐6 under radiolysis
Authors: Lamouroux C. , Aychet N. , Lelièvre A. , Jankowski C. K. , Moulin C.
Published: June 2004

The extraction of 135Cs from high‐activity liquid waste, arising from reprocessing of spent nuclear fuel, can be achieved by using calix[4]arene crown‐6 compounds. The radiolytic degradation of di(n‐octyloxy)calix[4]arene crown‐6 (octMC6), in aliphatic or aromatic solvent in contact with 3 M nitric acid, was studied by high‐performance liquid chromatography directly coupled to electrospray ionisation mass spectrometry (LC/ESI‐MS). More than 50 distinct degradation products were observed, and about 30 of these were identified. These compounds can be assigned to three categories, namely, products of reactions involving radical cleavage or addition, of oxidation reactions, or of aromatic substitution reactions. The major product, corresponding to substitution by an NO2 group, was quantified by external standard calibration using a purified synthetic sample. Despite the observation of all these degradation compounds, octMC6 appears to be remarkably stable under these drastic conditions, combining hydrolysis (HNO3 3 M) and an extreme exposure to radiolysis (106 Gy). Less than 35% degradation of octMC6 was observed in aromatic solvent under these conditions. Copyright © 2004 John Wiley & Sons, Ltd.
Micropropulsion for small spacecraft: a new challenge for field effect electric propulsion and microstructured liquid metal ion sources
Authors: Mitterauer J.
Published: June 2004

The growing interest in the use of microspacecraft is driving a critical need for new micropropulsion systems. The constraints on mass, dimension and power with which microspacecraft have to contend pose severe challenges to the system design. This general definition allows the inclusion of a wide range of concepts, from scaled‐down versions of existing thrusters operating at reduced power levels to completely redesigned microelectromechanical‐fabricated thrusters with micron characteristic sizes. More than ten years ago, microelectromechanical‐based propulsion was first introduced in the form of a proposed microfabricated field effect electric propulsion (FEEP) liquid metal ion thruster concept. Now a review will be given on basic features of liquid metal field emission sources, on selection criteria for liquid metal propellants for FEEP thrusters, on the principles of microstructured liquid metal ion sources (MILMIS) and finally on the miniaturization of MILMIS. Copyright © 2004 John Wiley & Sons, Ltd.
Kinetic instabilities in the NO/H2 reaction on platinum
Authors: Chau Thoi‐Dai , Visart de Bocarmé Thierry , Kruse Norbert
Published: June 2004

We have studied the catalytic reduction of nitric oxide (NO) with hydrogen (H2) on platinum using both field ion microscopy (FIM) and pulsed field desorption mass spectrometry (PFDMS). Under certain conditions of temperature and gas pressure this reaction exhibits non‐linear behaviour, i.e. hysteresis effects and rate oscillations occur. Ensembles of kink sites of the <100> zones are found to act as pacemakers, which is in line with earlier studies demonstrating {012} planes to ignite in a quasi‐concerted manner.1,2 Experiments with tips of varying radius of curvature always lead to the same sequence of image patterns. Large variations in the H2 partial pressure has little influence on the frequency of the rate oscillations.

Using PFDMS under the reaction conditions we show that NO+ rather than H2O+/H3O+ (the neutrals are formed during the reaction process) is the imaging species in FIM. Interestingly, $\hbox{PtO}_{{x}}^{n+} (x \leq 3)$ are seen in the mass spectra, indicating that the reaction is controlled by a vacant site mechanism with the inclusion of partial oxidation of the Pt surface. Copyright © 2004 John Wiley & Sons, Ltd.
Solute cluster formation in austenitic and ferritic alloys under ion irradiation: a three‐dimensional atom probe characterization
Authors: Krummeich R. , Pareige P. , Massoud J. P. , Jumel S.
Published: June 2004

Vessel and internal core steels of nuclear power reactors are subjected to energetic neutron irradiation. The production of point defects in the material results from elastic collisions in displacement cascades. On a microscopic scale, changes in the microstructure and local microchemistry are observed in both steels. On a global scale, a shift in the transient ductile to brittle temperature of vessel steels and an increase in the irradiation‐assisted stress‐corrosion‐cracking susceptibility of internal core stainless steels are observed. Also, on a nanometre scale, radiation‐induced phase transformation occurs in both steels. A systematic approach has proved its efficiency here to study the specific role of displacement cascades on cluster formation in two different materials: ferritic steels (bcc structure) and austenitic steels (fcc structure). In order to produce the primary knock atom, model ferritic steels containing a small amount of copper as well as a commercial austenitic steel (316) were irradiated using Fe and Ni ions, respectively. The different resulting microstructures are then studied on a nanoscale using tomographic atom probe three‐dimensional reconstruction. Copyright © 2004 John Wiley & Sons, Ltd.
Three‐dimensional atom probe study of irradiated, annealed and re‐irradiated VVER 440 weld metals
Authors: Pareige P. , Radiguet B. , Suvorov A. , Kozodaev M. , Krasikov E. , Zabusov O. , Massoud J. P.
Published: June 2004

The radiation embrittlement of the welds of old VVER 440 reactor pressure vessels promoted research on technical ways to ensure their safe operation during design service life. One of those is the recovery annealing of the reactor pressure vessel. Today, very few data are available concerning re‐irradiated materials. These data are essential in order to understand the mechanism of re‐embrittlement and to be able to predict the evolution of the microstructure and the mechanical properties of the steel during in‐service re‐irradiation. For that purpose a research programme was launched to carry out atom probe studies of the microstructure of weld metals in irradiated, irradiated–annealed and re‐irradiated conditions. This work demonstrates that neutron irradiation promotes the formation of ultra‐fine copper‐enriched clusters and solute segregation to crystal defects in these Cr–Mo–V steels. The study of the annealed materials allows us to explain how the mechanical properties of the irradiated materials can be recovered. Also, study of the re‐irradiated material points out the non‐detection of copper‐enriched clusters and the phosphorus behaviour during re‐irradiation. Copyright © 2004 John Wiley & Sons, Ltd.
Characterization of the precipitation in Al–Li–Cu–Mg–(Mn, Zr) alloys
Authors: Davin Laury , Cerezo Alfred , Gao Nong , Starink Marco
Published: June 2004

The three‐dimensional atom probe has been used to characterize the precipitates in two Li‐containing 2xxx series aluminium alloys: Al–6Li–Cu–Mg–0.2Mn (alloy A) and Al–6Li–Cu–Mg–0.03Zr (alloy B). The alloys have been heat treated at 150°C for times in the range 6–24 h. In alloy A, the particles identified can be classified into two categories: those rich in Cu and Mg (similar to GPB zones and S′ precipitates); and spherical particles rich in Li (δ′ precipitates). Clusters rich in Li are also observed. The same phases are observable in alloy B, although growth of the δ′ phase precipitates is accompanied by the formation of a Zr‐rich phase similar to β′. Copyright © 2004 John Wiley & Sons, Ltd.
Oxidation improvement of field electron emission from diamond nanomaterials
Authors: Karabutov A. V. , Gordeev S. K. , Ralchenko V. G. , Korchagina S. B. , Maslakov K. I. , Dementjev A. P.
Published: June 2004

Porous diamond/sp2‐bonded carbon nanocomposites were studied to determine how their field electron emission properties and electrical conductivity depend on composition and post‐growth treatment. It was found that a treatment enriching the nanocomposites with oxygen could significantly improve the field emission from the diamond samples. The oxidized composites exhibited lower emission threshold fields (Eth = 1–2 V µm−1 compared with Eth = 4–6 V µm−1 for non‐oxidized samples) and improved emission uniformity (the number of emission sites per unit area). The composites with low sp2‐bonded carbon content, i.e. the more porous samples, typically show better results. The structure of the samples was studied using a C KVV Auger spectrometer, with x‐ray excitation of Auger emission. Possible reasons for the emission improvement by oxidation in this two‐phase carbon system are discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Study of modulation methods in field emission displays
Authors: Wei Lei , Zhang Xiaobing , Li Juntao , Wang Baoping , Yin Hanchun
Published: June 2004

Field emission displays have many characteristics that are similar to cathode ray tubes but the field emission display panel can be thin. With the development of field emission materials, field emission devices have shown promise for display devices in the near future. In this paper, an electron optical system is introduced into a field emission display device. The modulation voltage changes the divergence angle of the electron beam. Consequently, the current of the electron beam that bombards the phosphor screen can be modulated. From the simulation results it can be seen that the modulation voltage is smaller than that for a conventional triode. Copyright © 2004 John Wiley & Sons, Ltd.
Study of the self‐sustaining discharge gas sensor with a carbon nanotube cathode
Authors: Li Xin , Bai Peng , Liu Junhua , Zhu Chang‐Chun
Published: June 2004

This method, which recognizes the species and concentration of gases by its Townsand discharge I–V curve, provides good stability and selectivity. Among the many factors affecting Townsand discharge, the most important one is the shape of the electrode. Four kinds of tip electrode are developed and discussed in this paper: metal, tungsten, carbon nanotube‐covered metal and carbon nanotube‐covered tungsten. The electric field of the tungsten tip is higher than that of the metal tip. If covered with carbon nanotube, the electric fields of both tips are threefold higher. Of the two tips, the carbon nanotube‐covered tungsten tip is the most promising. The large space between the two electrodes, which is 1.65 mm, helps the gas flow and the gas sensor recovery from electron affinity. Copyright © 2004 John Wiley & Sons, Ltd.
Effect of surface treatment on printed carbon nanotube field emitters
Authors: Ren Hao , Deng S. Z. , Chen Jun , She J. C. , Xu N. S.
Published: June 2004

The effects of different surface treatments on printed carbon nanotube thick‐film field emitters are described. Surface treatments using chemical etching and physical plasma etching techniques were purposely developed. The surface morphology and field emission properties of the carbon nanotube emitters after different surface treatments were characterized. It was found that the etching processes can effectively improve the field emission property through increasing the extent of protrusion of carbon nanotubes out of the surface of emitters, resulting in an increase in the field enhancement factor β. Copyright © 2004 John Wiley & Sons, Ltd.
Template‐based synthesis of carbon nanofibres and their field emission characteristics
Authors: Wu Q. B. , Ren S. , Deng S. Z. , Chen Jun , She J. C. , Xu N. S.
Published: June 2004

A synthesis technique based on an anodic aluminium oxide (AAO) template was developed to synthesize carbon nanofibres via thermal decomposition of acetylene using nickel as a catalyst. The structure and morphology of the nanofibres were studied with scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. It was found that most of the carbon nanofibres have a diameter of 150 nm, similar to that of the template nanopores. Also, they have novel shapes. Their electron field emission property was measured and a threshold field of 6.6 MV m−1 was observed. Copyright © 2004 John Wiley & Sons, Ltd.
Brightness of electron beam emitted from a single pentagon on a multiwall carbon nanotube tip
Authors: Hata Koichi , Takakura Akihiro , Ohshita Akinori , Saito Yahachi
Published: June 2004

A capped multiwall carbon nanotube with a clean surface gives field emission patterns consisting of six pentagonal rings corresponding to pentagons located at the tip. To evaluate the optical properties of a single pentagon as an electron source, the I–V characteristics and angular current densities for a single clean pentagon have been measured by probe‐hole‐type field emission microscopy. Reduced brightness estimated from the angular current density and the geometrical size of the pentagon reached ∼5.6 × 109 A m−2 sr−1 V−1 at an emission current of 53 nA. This value is one order of magnitude or more higher than that of an individual multiwall carbon nanotube field emitter reported by Jonge et al. Copyright © 2004 John Wiley & Sons, Ltd.