bluuebunny/crossref_metadata_2025_split huggingface dataset:
Compressive properties of soybean oil‐based polymers at quasi‐static and dynamic strain rates
Authors: Song Bo , Chen Weinong , Liu Zengshe , Erhan Sevim Z. 
Published: December 2005

AbstractQuasi‐static and dynamic compressive properties of three soybean oil‐based polymeric materials, which were made through the reaction of epoxidized soybean oil with diamine compounds, have been determined. Quasi‐static properties were determined with an MTS 810 hydraulically driven testing machine, whereas dynamic experiments were conducted with a split Hopkinson pressure bar (SHPB) modified for low‐impedance material testing. All three materials were capable of deforming to very large strains, with significant nonlinear stress–strain response. Their compressive behaviors were strain‐rate sensitive with distinctive rate sensitivities. On the basis of the experimental results at various strain rates, a compressive one‐dimensional stress–strain material model with strain‐rate effects was developed to describe the experimental results for all three materials under both quasi‐static and dynamic loading conditions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 2006
Cascade model for coupled two‐component polymer gels
Authors: Mao Ching‐Feng , Chen Jia‐Chin 
Published: December 2005

AbstractA cascade model for the network of coupled two‐component polymer gels is presented. The network formation is assumed to be primarily due to the interaction between the functional groups of two unlike polymers. The gel modulus G versus polymer concentration C curve is constructed using the cascade formalism. The variation of G versus C curves with respect to the concentration ratio r of the two components is found to be the characteristics of mixed gels. The model parameters can be obtained by fitting G versus C curves using a nonlinear least‐squares method (the gel‐modulus approach). The approach is applied to the experimental data for galactomannan/xanthan and glucomannan/xanthan mixed gels. Finally we discuss the gel point predicted by the cascade model. The critical concentration C0 for the gel point is strongly dependent on r and the functionalities for both polymers. The C0 versus r curve is easily obtained by experiment, and can be used to evaluate the model parameters (the gel‐point approach). The experimental data for galactomannan/xanthan mixed gels is tested to demonstrate the validity of the gel‐point approach. The advantages and limitations of both approaches are discussed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006
Properties of highly filled polypropylene derivative composites containing calcite and zeolite
Authors: Biswas Jagannath , Kim Hyun , Choe Soonja 
Published: December 2005

AbstractThis work aims to study the effects of high loading (total 50 wt %) of inorganic calcite, zeolite particulates, and calcite/zeolite mixture with structurally different copolymer [CoPP; poly(propylene‐co‐ethylene)] and terpolymer [TerPP; poly(propylene‐co‐ethylene‐co‐1‐butene)] systems. Melt processing is the sole mode of mixing particulates with polymer for making master batch sample throughout this work. Mechanical properties, like the modulus and yield stress, continuously increase up to a critical zeolite ratio in calcite/zeolite mix and then decrease after exceeding the critical concentration. The impact strength of the composites is not improved by replacing the calcite portion from the mix with zeolite. Morphological study was carried out for matrix–filler dispersion observation. The complex melt viscosity, increased for both systems with increasing zeolite content, indicates extra processing difficulties because of high filler volume. Burning properties and thermal stability of CoPP and TerPP composites with 50 wt % filler systems were also studied. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006
Aging behavior of a hot‐cured epoxy system
Authors: Fata Davis , Possart Wulff 
Published: December 2005

AbstractThe thermal and hydro‐thermal aging of a hot‐cured epoxy system (diglycidylether of bisphenol A (DGEBA) + dicyandiamide (DDA)) in the glassy state is revisited using DSC and IR attenuated total reflection spectroscopy. Because of the diffusion of DDA from the solid particles into the liquid DGEBA matrix, curing produces a highly crosslinked amorphous matrix that contains low crosslinked amorphous regions. After full curing, the network possesses a relatively low molecular mobility and no residual reactive groups. Thermal and hydro‐thermal loading is performed at 60°C, well below the principal glass transition temperature (Tg1 = 171°C). Both aging regimes cause significant chemical and structural changes to the glassy epoxy. It undergoes a phase separation of relatively mobile segments inside the low mobile matrix, providing a second glass transition that shifts from Tg2 = 86–114°C within 108 days of aging. This phase separation is reversible on heating into the viscoelastic state. Hydro‐thermal aging leads to a reversible and a nonreversible plasticizing effect as well. On thermal aging, no chemical changes are observed but hydro‐thermal aging causes significant chemical modifications in the epoxy system. These modifications are identified as a partial degradation of crosslinks produced by the cyano groups of the DDA and correspond to the nonreversible plasticitation. These changes in the cured epoxy should exert an influence on the mechanical properties of an adhesive bond. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006
Mechanical and acoustic frequency responses in flat hot‐compacted polyethylene and polypropylene panels
Authors: Jenkins M. J. , Hine P. J. , Hay J. N. , Ward I. M. 
Published: December 2005

AbstractA range of flat hot‐compacted single‐polymer composite panels made from oriented polypropylene and polyethylene with differing dynamic modulus and damping capacity were freely suspended and subjected to mechanical excitation, allowing their acoustic frequency response over the audio bandwidth to be measured. The audio response over selected bands was correlated with the dynamic modulus and damping capacity measured in bending in these materials and compared with the response of a traditional composite material, namely, carbon‐fiber‐reinforced epoxy resin. Low damping and high dynamic modulus were found to result in relatively high output levels from the hot‐compacted flat panels, which contrasted with the results previously measured on a traditional cone‐shaped speaker made from a hot‐compacted polypropylene material, which found high damping to be advantageous. The results of the current study on flat panels are explained in terms of mechanical impedance of the panels and their corresponding efficiency. It was concluded that the best flat‐panel audio response came from compacted polyethylene sheets, which combined high stiffness, low density, and a low level of damping. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006
Use of bacteria in anti‐cancer therapies
Authors: Ryan Rachel M. , Green Jeffrey , Lewis Claire E. 
Published: December 2005

AbstractWhile a number of valid molecular targets have been discovered for tumours over the past decade, finding an effective way of delivering therapeutic genes specifically to tumours has proved more problematic. A variety of viral and non‐viral delivery vehicles have been developed and applied in anti‐cancer gene therapies. However, these suffer from either inefficient and/or short‐lived gene transfer to target cells, instability in the bloodstream and inadequate tumour targeting. Recently, various types of non‐pathogenic obligate anaerobic and facultative anaerobic bacteria have been shown to infiltrate and selectively replicate within solid tumours when delivered systemically. This has prompted the development of cancer gene therapy protocols that use such bacteria as gene delivery vehicles. Here, we review the evidence for the success of these in pre‐clinical models and clinical trials, as single modality treatments and in combination with conventional cancer therapies. BioEssays 28:84–94, 2006. © 2005 Wiley Periodicals, Inc.
Multicellular redox regulation: integrating organismal biology and redox chemistry
Authors: Blackstone Neil W. 
Published: December 2005

AbstractEarly in the 20th century, Charles Manning Child attributed organismal gradients in metabolism to interactions among groups of cells. Metabolic gradients are now firmly grounded in redox chemistry, yet modern work on metabolic signaling has consistently focused on the cellular level. Multicellular redox regulation, however, may occur when redox state is determined by the behavior of a group of cells. For instance, typically an abundance of substrate will shift the redox state of mitochondria in the direction of reduction, leading to increased reactive oxygen species (ROS). These ROS, in turn, may modify the conformation and activity of proteins involved in signaling pathways, resulting in phenotypic changes. In contrast, if substrate triggers the contractions of a muscular structure comprising mitochondrion‐rich cells, the resulting metabolic demand may shift the redox state in the direction of oxidation, with a corresponding decrease of ROS and different phenotypic effects. Indeed, colonial hydroids exemplify this process. Parallel examples may occur whenever mitochondria are concentrated in cells of structures that can respond to environmental perturbations with increased metabolic demand. In these circumstances, predicting the direction of metabolic signaling may require an understanding of events at the organismal level. BioEssays 28:72–77, 2006. © 2005 Wiley Periodicals, Inc.
Hypothesis: transcript‐templated repair of DNA double‐strand breaks
Authors: Trott Deborah A. , Porter Andrew C.G. 
Published: December 2005

AbstractTwo mechanisms are available for the repair of DNA double‐strand breaks (DSBs) in eukaryotic cells: homology directed repair (HDR) and non‐homologous end‐joining (NHEJ). While NHEJ is not restricted to a particular phase of the cell cycle, it is incapable of accurately repairing DBSs that have suffered a loss or gain of nucleotide sequence information. In contrast, HDR achieves accurate repair of such DSBs by use of a sister chromatid as a DNA template, but is restricted to cell cycle phases (S/G2) when such templates are available. In this scheme, G1 cells appear to lack a mechanism for the accurate repair of certain DSBs, and an ability to use alternative templates would be highly advantageous. Considered here, therefore, is the possibility that RNA transcripts are used as templates for HDR. Potential mechanisms for transcript‐templated HDR, and ways in which it might be detected, are presented. BioEssays 28:78–83, 2006. © 2005 Wiley Periodicals, Inc.
Plants on red alert: do insects pay attention?
Authors: Schaefer H. Martin , Rolshausen Gregor 
Published: December 2005

AbstractTwo recent hypotheses have proposed that non‐green plant colouration evolved as a defence against herbivores, either as protective colouration promoting handicap signals indicating plant fitness or by undermining their crypsis. The handicap hypothesis posits a co‐evolutionary process between plants and herbivores, whereas the anti‐crypsis hypothesis suggests that an arms race between insects and plants is the evolutionary mechanism. Both explanations assume that insects are the evolutionary origin causing plants' colouration. Here, we propose a different hypothesis, termed the “Defence Indication hypothesis”. This idea focuses on the multiple protective functions of anthocyanins and carotenoids as pigments, and suggests that plant colouration evolved primarily in response to various stressors. Because pigments and defensive compounds share a common biosynthesis, the production of pigments also provides elevated defensive strengths against herbivores, a process termed priming. In effect, the Defence Indication hypothesis predicts that pleiotropic effects of the pigments and, more generally, plants' shared defence responses, explain why insects might react to plant colouration. BioEssays 28:65–71, 2006. © 2005 Wiley Periodicals, Inc.
Signal transduction in bacterial chemotaxis
Authors: Baker Melinda D. , Wolanin Peter M. , Stock Jeffry B. 
Published: December 2005

AbstractMotile bacteria respond to environmental cues to move to more favorable locations. The components of the chemotaxis signal transduction systems that mediate these responses are highly conserved among prokaryotes including both eubacterial and archael species. The best‐studied system is that found in Escherichia coli. Attractant and repellant chemicals are sensed through their interactions with transmembrane chemoreceptor proteins that are localized in multimeric assemblies at one or both cell poles together with a histidine protein kinase, CheA, an SH3‐like adaptor protein, CheW, and a phosphoprotein phosphatase, CheZ. These multimeric protein assemblies act to control the level of phosphorylation of a response regulator, CheY, which dictates flagellar motion. Bacterial chemotaxis is one of the most‐understood signal transduction systems, and many biochemical and structural details of this system have been elucidated. This is an exciting field of study because the depth of knowledge now allows the detailed molecular mechanisms of transmembrane signaling and signal processing to be investigated. BioEssays 28:9–22, 2006. © 2005 Wiley Periodicals, Inc.
Controlling the stem cell niche: right time, right place, right strength
Authors: Niemann Catherin 
Published: December 2005

AbstractWnt signalling through β‐catenin plays a pivotal role during embryonic pattern formation, cell fate determination and tissue homeostasis in the adult organism. In the skin, as in many other tissues, Wnt/β‐catenin signalling can control lineage determination and differentiation. However, it was not known whether Wnt/β‐catenin signalling is an immediate regulator of the stem cell niche in skin tissue. A recent publication now provides evidence that Wnt/β‐catenin signalling exerts a direct effect on the stem cell compartment by inducing quiescent stem cells to enter the cell cycle during early stages of hair follicle regeneration. In addition, the authors demonstrate that β‐catenin is required for maintenance of the stem cell pool in the tissue.1 The data suggest that a gradient in Wnt/β‐catenin activity levels can induce different responses within distinct cell populations reflected by activation of distinct transcriptional profiles. BioEssays 28:1–5, 2006. © 2005 Wiley Periodicals, Inc.
Resistance and the jumping gene
Authors: ffrench‐Constant Richard , Daborn Philip , Feyereisen Rene 
Published: December 2005

AbstractTransposons are well‐known architects of genetic change but their role in insecticide resistance has, until recently, only been speculated upon.1 Transposon insertion, or transposon‐mediated transposition, could alter either metabolic enzymes capable of degrading pesticides or could change the functionality of insecticide targets. The recent work of Aminetzach and coworkers2 suggests an exciting alternative, that transposon insertion can cause resistance by altering gene product function. This hypothesis is discussed in the light of other examples in which transposons have been implicated in insecticide resistance. BioEssays 28:6–8, 2006. © 2005 Wiley Periodicals, Inc.
Facilitating safer choices: use of warnings to dissuade viewing of pornography on the internet
Authors: Williams Katherine S. 
Published: December 2005

AbstractThere are many facets of child safety on the internet. Here the interest is in two scenarios: firstly, protection of children using the internet from viewing pornographic images; and secondly, the prevention of damage to children through adults viewing child pornography disseminated via the internet. The aim is to explore whether warnings or informational advice attached to sites would dissuade individuals from visiting them. Consideration will be given to the practicalities of attaching these warnings as well as to their success/failure in other media and across other products before assessing their utility in these scenarios. In essence, their use to protect children against viewing pornography is probably of little value, and may be counterproductive except in helping carers to guide safe use on the internet. Use of informational advice attached to child pornography sites may have more success and be worth pursuing, as might realistic warnings of prosecution. More research needs to be conducted into automatic means of assessing the nature of sites, into the mechanics of successful warnings on the internet and into their effects in this medium and for this material. Copyright © 2005 John Wiley & Sons, Ltd.
Using computer‐assisted self‐interviewing (CASI) questionnaires to facilitate consultation and participation with vulnerable young people
Authors: Davies Murray , Morgan Alun 
Published: December 2005

AbstractThis paper explores computer‐assisted self‐interviewing (CASI) as a methodology for consulting with vulnerable children. The authors provide a brief review of the literature in this area, indicating that computer‐mediated environments for self‐administered questionnaires can be particularly helpful in enabling data to be obtained about sensitive subjects. A case example is provided of Viewpoint Interactive, a CASI application in use in the UK in local authority children's services, education, and in learning disability child care practice. The paper concludes that CASI as a methodology can assist with consultation, and that it may provide a useful additional tool in the complex process of moving beyond consultation alone to the development of increased and more effective participation for vulnerable children in the provision of their care. Copyright © 2005 John Wiley & Sons, Ltd.
Cationic P–S–X cages (X=Br, I)
Authors: Gonsior Marcin , Krossing Ingo , Matern Eberhard 
Published: December 2005

AbstractThe first condensed‐phase preparation of ternary P–Ch–X cations (Ch=O–Te, X=F–I) is reported: [P5S3X2]+, [P5S2X2]+, and [P4S4X]+ (X=Br, I). [P5S3X2]+ is formed from the reaction of the Ag+/PX3 reagent with P4S3. The [P5S3X2]+ ions have a structure that is related to P4S5 by replacing PS by P+X and S in the four‐membered ring by P(X). We provide evidence that the active ingredient of the Ag+/PX3 reagent is the (H2CCl2)Ag–X–PX2+ cation. The latter likely reacts with the HOMO of P4S3 in a concerted HOMO–LUMO addition to give the P5S3X2+ ion as the first species visible in situ in the low‐temperature 31P NMR spectrum. The [P5S3X2]+ ions are metastable at −78 °C and disproportionate at slightly higher temperatures to give [P5S2X2]+ and [P4S4X]+, probably with the extrusion of 1/n (PX)n (X=Br, I). All six new cage compounds have been characterized by multinuclear NMR spectroscopy and, in part, by IR or Raman spectroscopy. The [P5S2X2]+ salts have a nortricyclane skeleton and were also characterized by X‐ray crystallography. The structure of the [P4S4X]+ ion is related to that of P4S5 in that the exo‐cage PS bond is replaced by an isoelectronic P+X moiety.
Discovery and Structure–Activity Relationship Studies of a Unique Class of HIV‐1 Integrase Inhibitors
Authors: Dayam Raveendra , Sanchez Tino , Neamati Nouri 
Published: December 2005

AbstractHIV‐1 integrase (IN) is an essential enzyme for viral replication and a validated target for the development of drugs against AIDS. Currently there are no approved drugs that target IN. However, new IN inhibitors are under clinical investigation. As more IN inhibitors enter human drug trials, there is a growing need for the design of novel lead compounds with diverse structural scaffolds and promising pharmacokinetic properties to counteract the difficulties observed with first‐generation IN inhibitors. We have identified a novel class of IN inhibitors through the systematic exploration of structure–activity relationships in a series of linomide analogues. The predicted bound conformation of the most active analogues inside the IN active site also supports the observed structure–activity correlation in this new compound class.
Individualizing combination of two antiproliferative immunosuppressants with pharmacodynamic modeling of stimulated lymphocyte responses
Authors: Berry Vishal , Magill Amy , Yost Mary , Janosky Janine , Sindhi Rakesh 
Published: December 2005

AbstractBackgroundUnpredictable serious adverse events (SAE) of immunosuppression, e.g. nephrotoxicity, with the nephrotoxic immunosuppressants have fostered interest in alternative regimens, which contain two antiproliferative agents, and individualized therapy. However, titration of such combinations to individual needs is not understood.Specific AimTo determine concentration (C) mixtures of mycophenolate mofetil (MMF) and sirolimus (SRL), which produce half‐maximal inhibitory effect (EC50) on human lymphocytes from individual subjects.MethodsConcentration mixtures of MMF (0–5 μg/ml) and SRL (0–30 ng/ml) were incubated with whole blood from each of five healthy human subjects. The intracellular cytokines IL‐2, TNF‐α, and IFN‐γ were measured in PMA‐ionomycin‐stimulated T‐cells (CD4+), while CD54, CD95, CD86, CD25, CD69, and CD71 were measured in pokeweed mitogen‐stimulated B‐cells, by flow cytometry. Pharmacodynamic (PD) relationships were evaluated using Hill equations modified for single and multidrug regimens, and expressed as EC50 for each target receptor.ResultsNo change was seen in the expression of the T‐cell cytokines with either MMF or SRL. Each B‐cell receptor was inhibited with increasing concentrations of either MMF or SRL. Each B‐cell receptor was also inhibited half‐maximally at lower concentrations of MMF in the presence of SRL, than with either agent alone, for the test population of five subjects together, and for each of five individual subjects. However, each subject showed distinctly different amounts of MMF and SRL that needed to be present together, in order to produce an identical inhibitory effect on lymphocyte function.ConclusionsPD analysis of biological effect can potentially predict optimal concentration mixtures of two immunosuppressants for individual recipients, and enhance rejection prophylaxis and safety. While this holds promise for drug development efforts, clinical application must await correlation of lymphocyte markers with post‐transplant clinical outcomes. © 2005 Wiley‐Liss, Inc.