bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phenomenological modeling of anomalous diffusion in polymers
Authors: Pomerantsev Alexey L. 
Published: March 2005

AbstractBoth normal and anomalous diffusion kinetics are considered in this article. Models of the relaxation, convection, and wetting–drying‐cycle kinetics and some other kinds of diffusion kinetics are evaluated. Analytically tractable solutions (when available) are presented. All calculations have been performed with the new nonlinear regression software Fitter (Moscow, Russia). © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1102–1114, 2005
Thickness‐dependent sorption and effects of physical aging in a polyimide sample
Authors: Punsalan David , Koros William J. 
Published: March 2005

AbstractThe solubility of a relatively noninteracting gas (CH4) was measured and compared for samples of vastly different thicknesses (25.4 vs 0.1 μm) to investigate the possibility of thickness‐dependent sorption and physical aging in glassy polymers. Changes in the sorption due to physical aging in these dense samples were observed and compared. To further compare the tendency of free‐volume relaxations in samples of different thicknesses, a variety of conditioning sorption tests were performed in which increases in the CH4 sorption due to high‐pressure CO2 exposure were observed and then compared after sample degassing. The reduction in CH4 solubility was related to excess free‐volume relaxations, and response comparisons of samples of widely different film thicknesses supported the notion of thickness‐dependent physical aging in glassy polymers. To the authors' knowledge, this was the first direct observation of a significant differences in gas solubility in glassy polymers due to the film thickness and aging time. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1115–1121, 2005
Kinetic study of the degradation of acrylonitrile–acrylamide copolymers
Authors: Hou Chen , Qun Wang , Qu Rong‐Jun , Wang Cheng‐Guo 
Published: March 2005

AbstractDifferential scanning calorimetry was used to investigate the degradation of acrylonitrile–acrylamide copolymers in air. The apparent activation energy of degradation of the copolymers was calculated with the Kissinger method. The effects of the copolymerization conditions on the apparent activation energy of the copolymers were studied. Increasing the dimethylformamide concentration in the solvent mixture led to a rapid increase in the apparent activation energy of degradation of the acrylonitrile–acrylamide copolymers. The apparent activation energy decreased quickly as the comonomer acrylamide concentration increased, and this change became less prominent as the acrylamide/acrylonitrile weight ratio increased beyond 5/95. The apparent activation energy increased as the copolymerization temperature increased. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1017–1020, 2005
Gel formation in diimide‐hydrogenated polymers
Authors: Lin Xingwang , Pan Qinmin , Rempel Garry L. 
Published: March 2005

AbstractThe hydrogenation of diene‐based polymers via diimide is a very attractive alternative to the conventional catalytic hydrogenation route based on gaseous molecular hydrogen. However, serious crosslinking always accompanies it and limits the end‐use properties of the polymers. Gel formation in polymers that are hydrogenated via diimide has been investigated in detail through an inspection of all the chemical reactions involved in the process. The results indicate that hydrogen peroxide decomposition, some reactions related to oxygen, and the redox reaction between hydrogen peroxide and hydrazine are capable of generating radicals. However, radicals generated in the aqueous phase do not appear to initiate the crosslinking of diene‐based polymers in the latex form. It is proposed that the primary radicals giving rise to crosslinking are generated in the polymer phase in situ, and the step responsible for generating these organic radicals is possibly the diimide disproportionation reaction. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1122–1125, 2005
Effect of calcium carbonate on the mechanical and thermal properties of isotactic polypropylene/ethylene vinyl acetate blends
Authors: Öksüz Mustafa , Yıldırım Hüseyin 
Published: March 2005

AbstractThe effect of calcium carbonate (CaCO3) on the mechanical properties (with heat treatment) and thermal properties of polypropylene and isotactic polypropylene (i‐PP)/ethylene vinyl acetate (EVA) blends was investigated. CaCO3, in five different concentrations (3, 6, 9, 12l, and 15 wt %), was added to i‐PP/EVA (88/12) to produce ternary composites. The mechanical properties, including the yield and tensile strengths, elastic modulus, Izod impact strength for notch radii of 0.25 and 1 mm, and hardness with and without an annealing heat treatment, and the thermal properties, such as the melting point and melt‐flow index, of the composites were investigated. The annealing heat treatment was carried out at 100°C for three different holding times: 75, 100, and 150 h. On the basis of the results, attempts were made to establish a relationship between the CaCO3 content, the annealing holding time, and the mechanical and thermal properties to obtain the best results. The tensile test results showed that the heat treatment was not effective for the ultimate tensile strength, and the yield strength and tensile strength decreased gradually as the CaCO3 content increased. However, CaCO3 was effective for higher elastic modulus, impact strength, and hardness values. A considerable increase in the elastic modulus was found with a 3% CaCO3 concentration for a holding time of 100 h. The maximum impact strength for a notch radius of 1 mm was obtained with 3% CaCO3 with annealing for a holding time of 100 h, whereas a 9% CaCO3 concentration produced higher toughness values for a notch radius of 0.25 mm. The fracture surfaces also supported the results from the Izod impact tests. Similarly, hardness values increased with the annealing heat treatment and increasing CaCO3 content. However, different holding times showed similar effects on the hardness values. The increased CaCO3 content caused the melting point to increase 5°C, whereas the melt‐flow index showed a sharp decrease as the CaCO3 content increased to 3%. Taking into consideration the mechanical and thermal properties and the annealing holding time, we recommend a CaCO3 concentration of 3% with an annealing heat treatment for 100 h for optimum properties of such ternary composites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1126–1137, 2005
Prevention of surgical adhesions with barriers of carboxymethylcellulose and poly(ethylene glycol) hydrogels synthesized by irradiation
Authors: Lee Joon‐Ho , Nho Young‐Chang , Lim Youn‐Mook , Son Tae‐Il 
Published: March 2005

AbstractBiocompatible and biodegradable hydrogels based on carboxymethylcellulose (CMC) and poly(ethylene glycol) (PEG) were prepared as physical barriers for preventing surgical adhesions. These interpolymeric hydrogels were synthesized by a γ‐irradiation crosslinking technique. Sections (1.5 cm × 1.5 cm) of the cecal serosa and an adjacent abdominal wall were abraded with a bone burr until the serosal surface was disrupted and hemorrhagic but not perforated, and the serosa of the cecum was sutured to the abdominal wall 5 mm away from the injured site. The denuded cecum was covered with either CMC/PEG hydrogels or a solution from a CMC/PEG hydrogel. A control rat serosa was not covered. Two weeks later, the rats were killed, and the adhesions were scored on a 0–5 scale. No treatment showed a significantly higher incidence of adhesions than the CMC/PEG hydrogels or solutions from the CMC/PEG hydrogels. This study demonstrated that CMC/PEG hydrogels could prevent intra‐abdominal adhesion in a rat model. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1138–1145, 2005
Bulk polymerization of styrene in the presence of organomodified montmorillonite
Authors: Liu Guodong , Zhang Liucheng , Zhao Dongmei , Qu Xiongwei 
Published: March 2005

AbstractThe effect of montmorillonite (Cloisite 6A) on the bulk polymerization of styrene initiated by benzoyl peroxide (BPO) was studied by the dilatometric determination of the polymerization rates. The bulk polymerization rates increased as the montmorillonite input quantity increased. The effect became greater when the BPO concentration decreased. Under the assumption that clay participated in the radical initiation reaction of the chains, the reaction orders for clay and BPO were determined to be approximately 1.0 and 0.5, respectively. X‐ray diffraction and thermogravimetric analysis studies showed that the structure and properties of the obtained polystyrene (PS)/montmorillonite nanocomposites were greatly affected by the BPO concentration. With lower BPO concentrations, a larger interlayer distance and a higher extent of delamination for the clay were observed in the obtained PS/montmorillonite nanocomposites. The nanocomposites prepared with lower BPO concentrations also showed higher heat‐decomposition‐resistance temperatures. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1146–1152, 2005
Swelling behavior and diffusion studies of high‐water‐retaining acrylamide/potassium methacrylate hydrogels
Authors: Mohan Y. Murali , Murthy P. S. Keshava , Rao K. Madhusudana , Sreeramulu J. , Raju K. Mohana 
Published: March 2005

AbstractPoly(acrylamide‐co‐potassium methacrylate) hydrogels were prepared by free‐radical simultaneous polymerization with aqueous solutions of acrylamide (AAm) and potassium methacrylate (KMA) with a redox initiator. The copolymerization was performed with eight different compositions of KMA at a fixed concentration of oil‐soluble crosslinkers, including 1,4‐butanediol diacrylate and ethylene glycol dimethacrylate (EGDMA). For every composition of AAm/KMA copolymer, the percentage swelling, swelling equilibrium, and diffusion characteristics were investigated. The copolymers were further studied for deswelling properties. The power law relationships of the hydrogels were evaluated for variation in terms of saline concentration. The AAm/KMA copolymers were confirmed by IR spectroscopy. Thermal studies of hydrogels were performed with differential scanning calorimetry and thermogravimetric analysis. EGDMA was found to be a better crosslinker for obtaining higher swelling and deswelling properties for the AAm/KMA hydrogels. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1153–1164, 2005
Transcriptome profiles for high‐cell‐density recombinant and wild‐type Escherichia coli
Authors: Haddadin Fu'ad T. , Harcum Sarah W. 
Published: March 2005

AbstractThe transcriptome profiles for wild‐type (plasmid‐free) and recombinant (plasmid‐bearing) Escherichia coli during well‐controlled synchronized high‐cell‐density fed‐batch cultures were analyzed by DNA microarrays. It was observed that the growth phase significantly affected the transcriptome profiles, and the transcriptome profiles were significantly different for the recombinant and wild‐type cultures. The response of the wild‐type and recombinant cultures to an isopropyl‐1‐thio‐β‐d‐galactopyranoside‐ (IPTG‐) addition was examined, where IPTG induced recombinant protein production in the plasmid‐bearing cultures. The IPTG‐addition significantly altered the transcriptome response of the wild‐type cultures entering the stationary phase. The IPTG‐induced recombinant protein production resulted in a significant down‐regulation of many energy synthesis genes (atp, nuo, cyo), as well as nearly all transcription‐ and translation‐related genes (rpo, rpl, rpm, rps, rrf, rrl, rrs). Numerous phage (psp, hfl) and transposon‐related genes (tra, ins) were significantly regulated in the recombinant cultures due to the IPTG‐induction. These results indicate that the signaling mechanism, associated with the recombinant protein production, may induce a metabolic burden in the form of a phage defense mechanism. Taken together, these results indicated that recombinant protein production initiated a cascade of transcriptome responses that down‐regulated the very genes needed to sustain productivity. © 2005 Wiley Periodicals, Inc.
Uncertainty analysis of penicillin V production using Monte Carlo simulation
Authors: Biwer Arno , Griffith Steve , Cooney Charles 
Published: March 2005

AbstractUncertainty and variability affect economic and environmental performance in the production of biotechnology and pharmaceutical products. However, commercial process simulation software typically provides analysis that assumes deterministic rather than stochastic process parameters and thus is not capable of dealing with the complexities created by variance that arise in the decision‐making process. Using the production of penicillin V as a case study, this article shows how uncertainty can be quantified and evaluated. The first step is construction of a process model, as well as analysis of its cost structure and environmental impact. The second step is identification of uncertain variables and determination of their probability distributions based on available process and literature data. Finally, Monte Carlo simulations are run to see how these uncertainties propagate through the model and affect key economic and environmental outcomes. Thus, the overall variation of these objective functions are quantified, the technical, supply chain, and market parameters that contribute most to the existing variance are identified and the differences between economic and ecological evaluation are analyzed. In our case study analysis, we show that final penicillin and biomass concentrations in the fermenter have the highest contribution to variance for both unit production cost and environmental impact. The penicillin selling price dominates return on investment variance as well as the variance for other revenue‐dependent parameters. © 2004 Wiley Periodicals, Inc.
Bioprocess intensification in flow‐through monolithic microbioreactors with immobilized bacteria
Authors: Akay G. , Erhan E. , Keskinler B. 
Published: March 2005

AbstractMicroporous polymers (with porosity up to 90%) with a well‐ prescribed internal microstructure were prepared in monolithic form to construct a flow‐through microbioreactor in which phenol‐degrading bacteria, Pseudomonas syringae, was immobilized. Initially, bacteria was forced seeded within the pores and subsequently allowed to proliferate followed by acclimatization and phenol degradation at various initial substrate concentrations and flow rates. Two types of microporous polymer were used as the monolithic support. These polymers differ with respect to their pore and interconnect sizes, macroscopic surface area for bacterial support, and phase volume. Polymer with a nominal pore size of 100 μm with phase volume of 90% (with highly open pore structure) yielded reduced bacterial proliferation, while the polymer with nominal pore size of 25 μm with phase volume of 85% (with small interconnect size and large pore area for bacterial adhesion) yielded monolayer bacterial proliferation. Bacteria within the 25 μm polymer support remained monolayered, without any apparent production of extracellular matrix during the 30‐day continuous experimental period. The microbioreactor performance was characterized in terms of volumetric utilization rate and compared with the published data, including the case where the same bacteria was immobilized on the surface of microporous polymer beads and used in a packed bed during continuous degradation of phenol. It is shown that at similar initial substrate concentration, the volumetric utilization in the microreactor is at least 20‐fold more efficient than the packed bed, depending on the flow rate of the substrate solution. The concentration of the bacteria within the pores of the microreactor decreases from 2.25 cells per μm2 on the top surface to about 0.4 cells per μm2 within 3 mm reactor depth. If the bacteria‐depleted part of the microreactor is disregarded, the volumetric utilization increases by a factor of 30‐fold compared with the packed bed. This efficiency increase is attributed to the reduction of diffusion path for the substrate and nutrients and enhanced availability of the bacteria for bioconversion in the absence of biofilm formation as well as the presence of flow over the surface of the monolayer bacteria. © 2005 Wiley Periodicals, Inc.
Evaluating environmental and social performance of large Portuguese companies: a balanced scorecard approach
Authors: Dias‐Sardinha Idalina , Reijnders Lucas 
Published: March 2005

AbstractA thematic balanced scorecard format was used to address environmental and social performance evaluation of 13 large companies operating in Portugal. Financial aspects of environmental and social company activities are also included. Companies were categorized as to their actual performance status using a predefined performance framework. Three categories were found: compliance with the law while emphasizing pollution control, pollution prevention and eco‐efficiency. Management tools and procedural matters were found to be most relevant for categorization. Often, reported information did not allow for quantitative evaluation of environmental burden reduction.Use of the thematic balanced scorecard format was useful to better understand the strengths and weaknesses of links between objectives and measurements, initiatives and achievements. Improvement as to environmental performance was found to be paralleled by increased social performance, suggesting that a multi‐level ‘sustainability’ performance categorization of these Portuguese companies is feasible. Driving forces for environmental management initiatives were found to differ by category of performance. Copyright © 2005 John Wiley & Sons, Ltd and ERP Environment.
Exploring individual and institutional drivers of proactive environmentalism in the US Wine industry
Authors: Marshall R. Scott , Cordano Mark , Silverman Murray 
Published: March 2005

AbstractIndustry transformation related to environmental stewardship proceeds through multiple stages, and there is as of yet no clear understanding of the importance of certain drivers of transformation at different stages. We bring together previous environmental management research regarding individual‐ and institutional‐level drivers of environmental stewardship to develop a model and series of questions regarding proactive environmental behavior in the US wine industry. A qualitative research method, including interviews and focus groups, is used to test the model. At the early stage of environmental transformation in the wine industry, we find that managerial attitudes and norms, existing regulations, employee welfare and competitive pressures are all strong drivers of proactive environmental behavior. However, our multi‐level analysis suggests that drivers of environmentalism vary in relevance and relative importance and that future environmental management research needs to consider the relationship between drivers of environmentalism and the stage of an industry's environmental transformation. Copyright © 2005 John Wiley & Sons, Ltd and ERP Environment.
Rhetoric and reality of corporate greening: a view from the supply chain management function
Authors: Preuss Lutz 
Published: March 2005

AbstractThe increasingly important economic role of supply chain management provides the backcloth against which this article examines what contribution the function can make to environmental protection. Theoretical perspectives on greener supply are developed and then tested against a sample of manufacturing companies. Environmental policy documents published by the sample companies seem to offer surface evidence for a proactive supply chain management role in environmental protection. Yet a more detailed examination of the three elements that constitute supply chain management – the management of the transformation of materials, the management of information flows and the management of supply chain relationships – finds a suboptimal situation for all three areas. In part this gap can be explained by limits in the technical capabilities of the supply chain. More important, however, are structural constraints that prevent the supply chain manager from actively searching for environmentally friendlier alternatives. Copyright © 2005 John Wiley & Sons, Ltd and ERP Environment.
The Target Discovery Process
Authors: Egner Ursula , Krätzschmar Jörn , Kreft Bertolt , Pohlenz Hans‐Dieter , Schneider Martin 
Published: March 2005

AbstractIn order to minimise attrition rates in drug development projects, a target discovery process is implemented to select and characterise the most suitable candidate kinase targets, before lead identification and lead optimisation are embarked upon. The process consists of 1) target selection, 2) target assessment, and 3) target validation. This rational approach to target discovery, as a prerequisite for lead discovery, ensures that new therapeutic targets fulfil a set of general criteria, as well as indication‐specific, descriptive and functional ones. The approach should ultimately maximise the likelihood of achieving target‐selective inhibition by small‐molecule inhibitors with minimal in vivo side effects and a therapeutic effect based on a sound biological hypothesis.
High‐Throughput Screening for Kinase Inhibitors
Authors: von Ahsen Oliver , Bömer Ulf 
Published: March 2005

AbstractFollowing G protein‐coupled receptors (GPCRs), protein kinases have become the second most important class of targets for drug discovery over the last 20 years. While only four kinase inhibitors have reached the market to date (Fasudil for rho‐dependent kinase, Rapamycin for TOR, Gleevec for BCR‐Abl, and Iressa for EGFR), many more are already in clinical development. A historical overview of kinase inhibitors was recently published by Cohen.1 After the previous successes, protein kinases are now regarded as attractive, well‐drugable targets, and the analysis of the human genome has yielded 518 protein kinases.2 We can thus expect screening for protein kinase inhibitors to become even more important in the future. In this review we will focus on the early steps of drug discovery programs producing new lead compounds. We will guide the reader through efficient state‐of‐the‐art assay development and high‐throughput screening of large chemical libraries for protein kinase inhibitors.
Heme Alkylation by Artesunic Acid and Trioxaquine DU1301, Two Antimalarial Trioxanes
Authors: Laurent Sophie A.‐L. , Loup Christophe , Mourgues Sophie , Robert Anne , Meunier Bernard 
Published: March 2005

AbstractThe sesquiterpene Artemisinin, an antimalarial drug that is effective against multidrug‐resistant Plasmodium falciparum strains, contains a 1,2,4‐trioxane, and the endoperoxide function plays a key role in its biological activity. However, its poor solubility means that hemisynthetic derivatives, such as artesunic acid, are preferred for drugs.The reductive activation of the peroxide function of artemisinin by iron(II)‐heme produces heme derivatives that are alkylated at meso positions by a C‐centered radical derived from artemisinin. We checked if the alkylating ability of trioxane‐based drugs toward heme, which might be related to its parasiticidal activity, is a general feature by comparing the chemical reactivity toward heme of the clinically relevant derivative artesunic acid and DU1301, a drug of the trioxaquine family, that is active against P. falciparum. Both artesunic acid and trioxaquine DU1301 efficiently alkylated the heme macrocycle after activation of their peroxide function by the iron(II) of heme itself and thus gave rise to covalently coupled heme–drug products. This heme–drug adduct formation might be related to the high antimalarial activity of DU1301.