bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of insoluble fibroin films without methanol treatment
Authors: Lv Qiang , Cao Chuanbao , Zhang Ying , Ma Xilan , Zhu Hesun 
Published: April 2005

AbstractInsoluble fibroin films were prepared without methanol treatment. A 15 wt % fibroin solution was obtained through concentration, and then, the insoluble film was achieved by the adjustment of the drying temperature and rate. These films were examined through Fourier transform infrared–attenuated total reflection, X‐ray diffraction, and scanning electron microscopy to determine the structure of the silk fibroin. The physical and mechanical properties were investigated to discover the feasibility of using these films as biomedical materials. When fibroin films were dried above 60°C, abundant β‐sheet crystals existed in the fibroin films, and many globule‐containing micelles aggregated and interacted with each other, which resulted in excellent mechanical properties of the regenerated fibroin films in the wet state. Interestingly, the amide III band of the random coil structure in the fibroin films dried at 70 and 80°C was shifted to a lower frequency, 1228 cm−1, which meant that a partly orientated structure formed. This may have also affected the mechanical properties of the fibroin films. The tensile strength and breaking elongation of the films dried at 70°C were 29.8 MPa and 59.6%, which is distinctly superior to fibroin films treated with methanol. If the drying temperature was raised to 60°C, the stability of the films in water was also excellent. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2168–2173, 2005
Preparation and characterization of micron‐sized non‐porous magnetic polymer microspheres with immobilized metal affinity ligands by modified suspension polymerization
Authors: Ma Zhi‐Ya , Guan Yue‐Ping , Liu Xian‐Qiao , Liu Hui‐Zhou 
Published: April 2005

AbstractA novel preparation method of micron‐sized non‐porous magnetic polymer microspheres with immobilized metal affinity ligands was developed. A modified suspension polymerization of methacrylate (MA) and divinylbenzene (DVB) was performed in the presence of oleic acid‐coated magnetic Fe3O4 nanoparticles to obtain magnetic poly (methacrylate‐divinylbenzene) (mPMA‐DVB) microspheres. Through ammonolysis using ethylenediamine (EDA) and subsequent carboxymethylation with chloroacetic acid, magnetic polymer microspheres with chelate ligands of iminodiacetic acid (IDA) were obtained. Charging with copper ions resulted in magnetic polymer microspheres capable of binding proteins that display metal affinity. The morphology, magnetic properties, and composition of magnetic polymer microspheres were characterized with scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and Fourier transform infrared spectroscopy (FTIR), respectively. Bovine hemoglobin (BHb) was adopted as a model protein to investigate their affinity adsorption capacity. It was found that the adsorption capacity was as high as 168.2 mg/g microspheres and with rather low non‐specific adsorption. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2174–2180, 2005
Effect of acrylic acid on the properties of recycled poly(vinyl chloride)/acrylonitrile–butadiene rubber blends
Authors: Ismail H. , Supri  , Yusof A. M. M. 
Published: April 2005

AbstractThe effect of acrylic acid (AAc) on the torque, stabilization torque, mechanical energy, swelling behavior, mechanical properties, thermal stability, and morphological characteristics of recycled poly(vinyl chloride)/acrylonitrile–butadiene rubber (PVCr/NBR) blends was studied. The blends were melt mixed at a temperature of 150°C and rotor speed of 50 rpm. AAc was used to improve the compatibility of PVCr/NBR blends. Virgin PVCv/NBR blends were prepared to provide a comparison. It was found that PVCr/NBR + AAc blends exhibit higher stabilization torque, mechanical energy, stress at peak, and stress at 100% elongation, but lower elongation at break and swelling index than those of PVCr/NBR and PVCv/NBR blends. SEM study of the tensile fracture surfaces of the blends indicated that the presence of AAc increased the interfacial interaction between PVCr and NBR phases, thus improving the compatibility between PVCr and NBR phases. However, thermal gravimetry analysis of the blends showed that the presence of AAc decreased the thermal stability of PVCr/NBR blends. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2181–2191, 2005
Gas barrier changes and morphological alterations induced by retorting in ethylene vinyl alcohol–based food packaging structures
Authors: López‐Rubio Amparo , Hernández‐Muñoz Pilar , Gimenez Enrique , Yamamoto Tomoyuki , Gavara Rafael , Lagarón Jose M. 
Published: April 2005

AbstractEthylene vinyl alcohol (EVOH)–based packaging structures were analyzed in terms of both barrier properties and morphological alterations after a retorting process and as functions of ethylene content. From the results, it was found that the samples do have a substantial decrease in oxygen barrier properties and that the kinetics of recovery strongly depends on the copolymer ethylene fraction. A morphological deterioration was also observed as a result of retorting, particularly for packaging structures composed of EVOH copolymers of low ethylene contents. However, the polymer morphology and barrier properties were restored after a dry thermal treatment of the retorted samples. Interestingly, preannealing of copolymers of low ethylene content rendered them more resistant to the retorting process by means of promoting both a more robust crystallinity and a lower water sorption capacity. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2192–2202, 2005
Physicomechanical properties of α‐cellulose–filled styrene–butadiene rubber composites
Authors: Haghighat M. , Zadhoush A. , Khorasani S. Nouri 
Published: April 2005

AbstractIn this research, the influence of adding α‐cellulose powder to styrene–butadiene rubber (SBR) compounds was investigated. Physicomechanical properties of SBR–α‐cellulose composites, including tensile strength, elongation, Young's modulus, tear strength, hardness, abrasion, resilience, and compression set, before and after ageing, were determined and analyzed. Young's modulus, hardness, and compression set increased and elongation and resilience decreased with increasing α‐cellulose loading in the composites, whereas tensile strength, tear strength, and abrasion resistance initially increased at low α‐cellulose concentration (5 phr), after which these properties decreased with increasing α‐cellulose content. Lower loadings of α‐cellulose (5 phr) showed better results than higher loadings, given that tensile strength, tear strength, and abrasion resistance increased at low α‐cellulose concentration. Theoretical prediction of elastic modulus was carried out using rule of mixtures, Hashin, Kerner, and Halpin–Tsai equations. Calculated results show that these equations are not suitable for accurate prediction for the work carried out. However, these models can be used with confidence for the prediction of elastic modulus because experimental results are higher than the calculated values. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2203–2211, 2005
Nanoencapsulation of capsaicin by complex coacervation of gelatin, acacia, and tannins
Authors: Xing Fubao , Cheng Guoxiang , Yi Kejing , Ma Linrong 
Published: April 2005

AbstractUsing gelatin and acacia as wall and capsaicin as core substance, nanocapsules were prepared by mixing two solutions of oppositely charged polymers, and then treated by hydrolysable tannins. The morphology and size distribution of the nanocapsules were analyzed by transmission electron microscope and laser particle size analyzer, respectively. The nanocapsules had a mean diameter of 300–600 nm, with mean drug loading content (20.81%) and encapsulation efficiency (81.17%) with good dispersion and spherical morphology. The interaction between gelatin and tannins is discussed in the article. Moreover, the addition of hydrolysable tannins in the system had an important influence on the morphology and particle distribution of the nanocapsules because of the synergistic actions of hydrogen bonding and hydrophobic effects. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2225–2229, 2005
Study on PET fiber modified by nanomaterials: Improvement of dimensional thermal stability of PET fiber by forming PET/MMT nanocomposites
Authors: Xiao Weizhen , Yu Huimin , Han Keqing , Yu Muhuo 
Published: April 2005

AbstractPoly(ethylene terephthalate) (PET) and PET/montmorillonite(MMT) (2.5 wt %) nanocomposites with high molecular weight were prepared by solid‐state polycondensation and their fiber was spun and drawn under various conditions. The influence of MMT nanomaterials on the thermal shrinkage of PET fiber was investigated and the structure was studied using the methods of WAXD, DSC, fiber orientation measurement, etc. The results showed that the MMT nanomaterials improved the thermal stability of microstructure of PET fiber. The fusion heat of PET/MMT was higher than that of PET, which generally implied the high orientation or high crystallinity. However, the degree of orientation and the crystallinity of PET/MMT fiber measured by WAXD were lower than that of pure PET fiber. It is suggested that the strong interaction between MMT layer and PET restricted the motions of PET molecular chains, which developed “a special continuous network structure” and prohibited the thermal shrinkage of PET fiber. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2247–2252, 2005
Equilibrium swelling studies of highly swollen acrylamide/mesaconic acid hydrogels
Authors: Üzüm Ömer Barış , Karadağ Erdener 
Published: April 2005

AbstractAcrylamide/mesaconic acid (AAm/MA) hydrogels were prepared by free radical solution polymerization in aqueous solution of acrylamide (AAm) with mesaconic acid (MA) as comonomer and two multifunctional crosslinkers such as ethylene glycol dimethacrylate (EGDMA) and 1,4‐butanediol dimethacrylate (BDMA). Swelling experiments were performed in water at 25°C, gravimetrically. The influence of mesaconic acid content in hydrogels was examined. Swelling of AAm/MA hydrogels was increased up to 2301% (for containing 20 mg MA and crosslinked by EGDMA) to 3296% (for containing 80 mg MA and crosslinked by BDMA), while AAm hydrogels swelled up to 1330% (crosslinked by BDMA) to 1400% (crosslinked by EGDMA). The values of equilibrium water content of the hydrogels are 0.9301–0.9706. Diffusion behavior was investigated. Water diffusion into hydrogels was found to be non‐Fickian in character. Diffusion coefficients of AAm/MA hydrogels were calculated by the short time approximation and found to be from 38.01 × 10−6 cm2 s−1 to 182.73 × 10−6 cm2 s−1. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2253–2259, 2005
Relying on electronic journals: Reading patterns of astronomers
Authors: Tenopir Carol , King Donald W. , Boyce Peter , Grayson Matt , Paulson Keri‐Lynn 
Published: April 2005

AbstractSurveys of the members of the American Astronomical Society identify how astronomers use journals and what features and formats they prefer. While every work field is distinct, the patterns of use by astronomers may provide a glimpse of what to expect of journal patterns and use by other scientists. Astronomers, like other scientists, continue to invest a large amount of their time in reading articles and place a high level of importance on journal articles. They use a wide variety of formats and means to get access to materials that are essential to their work in teaching, service, and research. They select access means that are convenient—whether those means be print, electronic, or both. The availability of a mature electronic journals system from their primary professional society has surely influenced their early adoption of e‐journals.
Distributed multi‐agent information filtering—A comparative study
Authors: Mukhopadhyay S. , Peng S. , Raje R. , Mostafa J. , Palakal M. 
Published: April 2005

AbstractInformation filtering is a technique to identify, in large collections, information that is relevant according to some criteria (e.g., a user's personal interests, or a research project objective). As such, it is a key technology for providing efficient user services in any large‐scale information infrastructure, e.g., digital libraries. To provide large‐scale information filtering services, both computational and knowledge management issues need to be addressed. A centralized (single‐agent) approach to information filtering suffers from serious drawbacks in terms of speed, accuracy, and economic considerations, and becomes unrealistic even for medium‐scale applications. In this article, we discuss two distributed (multi‐agent) information filtering approaches, that are distributed with respect to knowledge or functionality, to overcome the limitations of single‐agent centralized information filtering. Large‐scale experimental studies involving the well‐known TREC data set are also presented to illustrate the advantages of distributed filtering as well as to compare the different distributed approaches.
Quantitative analysis of helix–coil transition of block copolypeptide, Glu12–Ala12, by combined use of CD and NMR spectroscopy
Authors: Yamazaki Toshimasa , Furuya Hidemine , Watanabe Takeshi , Miyachi Sayaka , Nishiuchi Yuji , Nishio Hideki , Abe Akihiro 
Published: April 2005

AbstractTo investigate helix–coil transition mechanisms, conformations of Glu12–Ala12, EA, in aqueous solution have been studied in detail over the pH range from 2 to 8 and the temperature range from 20 to 60°C using CD and NMR spectroscopy. The 750‐MHz NMR spectra displayed excellent dispersion of the backbone amide proton signals, and permitted essentially complete sequence‐specific resonance assignments. These assignments, together with short‐ and medium‐range nuclear Overhauser effect (NOE) constraints and coupling constants, enable us to analyze conformational characteristics of all the residues in the EA peptide individually. A combined use of CD and NMR techniques reveals that the EA peptide assumes a stable α‐helix from Glu12 to Ala19 in 0.1M NaCl solution at 20°C above pH 7. The α‐helix is getting longer as decreasing pH. Below pH 4, the peptide assumes the longest α‐helix from Glu3 to Ala23. The important observation of the present study is that the helix–coil transition occurs stepwise, residue by residue, from both the N‐ and C‐termini of the α‐helix. No conformational equilibrium between the helical and random‐coil states is detected for the residues in the central region of the α‐helix. Quantitative analysis of temperature‐induced helix‐to‐coil transitions at various pHs provides a pH‐independent residual enthalpy change ΔHr = 0.95 kcal res−1. Similar values have been reported for a 50‐residue alanine‐rich peptide (1.2 kcal res−1), poly‐L‐glutamate (1.1 kcal res−1), poly‐L‐lysine (1.1 kcal res−1), and poly‐L‐alanine (0.86 kcal res−1). Those investigations, along with our present result, suggest that ΔHr is mainly determined by the transformation of the backbone associated with the disruption of the intramolecular hydrogen bond. These results should increase our understanding of the helix–coil transition. © 2005 Wiley Periodicals, Inc. Biopolymers (Pept Sci), 2005
A well‐defined amphipathic conformation for the calcium‐free cyclic lipopeptide antibiotic, daptomycin, in aqueous solution
Authors: Rotondi Kenneth S. , Gierasch Lila M. 
Published: April 2005

AbstractDaptomycin is a 13‐residue cyclic lipopeptide with Ca2+‐dependent bactericidal activity against a variety of high‐risk pathogens. Ring closure in daptomycin is via an ester linkage between the side chain of Thr4 and the C‐terminal carboxyl of the main chain; the N‐terminal residue is capped by a decanoyl aliphatic chain. Extensive NMR data obtained under solution conditions that minimize aggregation have provided constraints for a detailed conformational analysis of daptomycin in aqueous solution, which should facilitate the rational design of improved analogs and enhance understanding of its mode of action. Transannular and shorter‐range nuclear Overhauser effects (NOEs) as well as amide temperature shifts and 3JNHα coupling constants indicate that daptomycin adopts a well‐defined conformation containing a distorted hairpin formed by Gly5–D‐Ala6 type II′ β‐turn. A number of hydrophobic moieties (the lipid N‐cap and the Trp1 and Kyn13 side chains) are clustered at one end of the hairpin, while neutral polar and anionic residues are localized on the other end, leading to amphipathicity in the molecule. These features suggest a mode of action in which the large hydrophobic cluster of the peptide interacts with the acyl chain region of a membrane. This interaction may be facilitated by Ca2+ ions, both by neutralizing the anionic charges and by favoring association with the membrane head groups. Interestingly, our findings differ from two recent articles in which the aqueous conformation of Ca2+‐free daptomycin is reported to lack a well‐defined conformation (D. Jung, A. Rozek, M. Okron, and R. E. W. Hancock, Chemistry & Biology, 2004, Vol. 11, pp. 949–957) or is suggested to populate an alternate conformation (L.‐J. Ball, C. M. Goult, J. A. Donarski, J. Micklefield, and V. Ramesh, Organic & Biomolecular Chemistry, 2004, Vol. 2, pp. 1872–1878). © 2005 Wiley Periodicals, Inc. Biopolymers (Pept Sci), 2005
Metabolite profiling for analysis of yeast stress response during very high gravity ethanol fermentations
Authors: Devantier Rasmus , Scheithauer Britta , Villas‐Bôas Silas Granato , Pedersen Sven , Olsson Lisbeth 
Published: April 2005

AbstractA laboratory strain and an industrial strain of Saccharomyces cerevisiae were grown at high substrate concentration, so‐called very high gravity (VHG) fermentation. Simultaneous saccharification and fermentation (SSF) was applied in a batch process using 280 g/L maltodextrin as carbon source. It was shown that known ethanol and osmotic stress responses such as decreased growth rate, lower viability, higher energy consumption, and intracellular trehalose accumulation occur in VHG SSF for both strains when compared with standard laboratory medium (20 g/L glucose). The laboratory strain was the most affected. GC‐MS metabolite profiling was applied for assessing the yeast stress response influence on cellular metabolism. It was found that metabolite profiles originating from different strains and/or fermentation conditions were unique and could be distinguished with the help of multivariate data analysis. Several differences in the metabolic responses to stressing conditions were revealed, particularly the increased energy consumption of stressed cells was also reflected in increased intracellular concentrations of pyruvate and related metabolites. © 2005 Wiley Periodicals, Inc.
Anaerobic treatment of complex chemical wastewater in a sequencing batch biofilm reactor: Process optimization and evaluation of factor interactions using the Taguchi dynamic DOE methodology
Authors: Venkata Mohan S. , Chandrasekhara Rao N. , Krishna Prasad K. , Murali Krishna P. , Sreenivas Rao R. , Sarma P.N. 
Published: April 2005

AbstractThe Taguchi robust experimental design (DOE) methodology has been applied on a dynamic anaerobic process treating complex wastewater by an anaerobic sequencing batch biofilm reactor (AnSBBR). For optimizing the process as well as to evaluate the influence of different factors on the process, the uncontrollable (noise) factors have been considered. The Taguchi methodology adopting dynamic approach is the first of its kind for studying anaerobic process evaluation and process optimization. The designed experimental methodology consisted of four phases—planning, conducting, analysis, and validation connected sequence‐wise to achieve the overall optimization. In the experimental design, five controllable factors, i.e., organic loading rate (OLR), inlet pH, biodegradability (BOD/COD ratio), temperature, and sulfate concentration, along with the two uncontrollable (noise) factors, volatile fatty acids (VFA) and alkalinity at two levels were considered for optimization of the anae robic system. Thirty‐two anaerobic experiments were conducted with a different combination of factors and the results obtained in terms of substrate degradation rates were processed in Qualitek‐4 software to study the main effect of individual factors, interaction between the individual factors, and signal‐to‐noise (S/N) ratio analysis. Attempts were also made to achieve optimum conditions. Studies on the influence of individual factors on process performance revealed the intensive effect of OLR. In multiple factor interaction studies, biodegradability with other factors, such as temperature, pH, and sulfate have shown maximum influence over the process performance. The optimum conditions for the efficient performance of the anaerobic system in treating complex wastewater by considering dynamic (noise) factors obtained are higher organic loading rate of 3.5 Kg COD/m3 day, neutral pH with high biodegradability (BOD/COD ratio of 0.5), along with mesophilic temperature range (40°C), and low sulfate concentration (700 mg/L). The optimization resulted in enhanced anaerobic performance (56.7%) from a substrate degradation rate (SDR) of 1.99 to 3.13 Kg COD/m3 day. Considering the obtained optimum factors, further validation experiments were carried out, which showed enhanced process performance (3.04 Kg COD/m3‐day from 1.99 Kg COD/m3 day) accounting for 52.13% improvement with the optimized process conditions. The proposed method facilitated a systematic mathematical approach to understand the complex multi‐species manifested anaerobic process treating complex chemical wastewater by considering the uncontrollable factors. © 2005 Wiley Periodicals, Inc.
Potentiometric Detection of Single Nucleotide Polymorphism by Using a Genetic Field‐effect transistor
Authors: Sakata Toshiya , Miyahara Yuji 
Published: April 2005

AbstractPotentiometric measurement of allele‐specific oligonucleotide hybridization based on the principle of detection of charge‐density change at the surface of a gate insulator by using of a genetic field‐effect transistor has been demonstrated. Since DNA molecules are negatively charged in aqueous solution, a hybridization event at the gate surface leads to a charge‐density change in the channel of the FET and can be directly transduced into an electrical signal without any labeling of target DNA molecules. One of the unique features of our method is to utilize DNA binders such as intercalators as charged species for double‐stranded DNA after hybridization, since these are ionized and carry positive charges in aqueous solution. Single‐base mismatch of the target DNA could be successfully detected both with the wild‐type and with the mutant genetic FETs by controlling the hybridization temperatures and introducing Hoechst 33258 as DNA binder. The genetic FET platform is suitable as a simple, accurate, and inexpensive system for SNP typing in clinical diagnostics.