bluuebunny/crossref_metadata_2025_split huggingface dataset:
Model for reaction‐assisted polymer dissolution in LIGA
Authors: Larson Richard S. 
Published: April 2005

AbstractA new chemically oriented mathematical model for the development step of the LIGA process is presented (LIGA is an acronym for the German words Lithographie, Galvanoformung, and Abformung). The key assumption is that the developer can react with the polymeric resist material to increase the solubility of the latter, thereby partially overcoming the need to reduce the polymer size. The ease with which this reaction takes place is assumed to be determined by the number of side‐chain scissions that occur during the X‐ray exposure phase of the process. The dynamics of the dissolution process are simulated by the solution of the reaction diffusion equations for this three‐component, two‐phase system, the three species being the unreacted and reacted polymers and the solvent. The mass fluxes are described by multicomponent diffusion (Stefan–Maxwell) equations, and the chemical potentials are assumed to be given by the Flory–Huggins theory. Sample calculations are used to determine the dependence of the dissolution rate on key system parameters such as the reaction rate constant, polymer size, solid‐phase diffusivity, and Flory–Huggins interaction parameters. A simple photochemistry model is used to relate the reaction rate constant and the polymer size to the absorbed X‐ray dose. The resulting formula for the dissolution rate as a function of the dose and temperature is fit to an extensive experimental database to evaluate a set of unknown global parameters. The results suggest that reaction‐assisted dissolution is very important at low doses and low temperatures, the solubility of the unreacted polymer being too small for it to be dissolved at an appreciable rate. However, at high doses or at higher temperatures, the solubility is such that the reaction is no longer needed, and dissolution can take place via the conventional route. These results provide an explanation for the observed dependences of both the rate of dissolution and its activation energy on the absorbed dose. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 25–37, 2005
Study on preparation and tribological properties of epoxy resin/SiO2 hybrid thin film
Authors: Qi Chenze , Gao Hui , Yan Fengyuan , Liu Weimin , Bao Gaoqiang , Sun Xudong , Chen Jianmin , Zheng Xiaoming 
Published: April 2005

AbstractA series of organic–inorganic hybrid thin films are prepared by means of the sol–gel process in curing epoxy and hydrolyzing tetraethoxysilane. The epoxy group of γ‐glycidyloxipropyltrimethoxysilane can be incorporated into the sol–gel network to form the interaction between the inorganic and organic phases. Inorganic and organic components can be mixed on the nanometer scales, thereby leading to the formation of so‐called hybrid materials. Transmission electron microscopy examinations and atomic force microscopy are employed to study the morphology and roughness of the samples, respectively. In addition, the tribological behavior of dip‐coating thin films is evaluated by the use of a dynamic/static friction precision measurement apparatus (unidirectional sliding tester). The influences of the contents of both the filler and the coupling agent on the tribological properties of the nanocomposite thin films are systematically studied. These results indicate that the films sliding against a GCr15 steel ball display excellent antiwear and friction reduction performance. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 38–43, 2005
Preparation of titanium dioxide/poly(methyl methacrylate‐co‐n‐butyl acrylate‐co‐methacrylic acid) hybrid composite particles via emulsion polymerization
Authors: Yu Dong‐Guk , An Jeong Ho , Bae Jin Young , Ahn Seong Deok , Kang Seung‐Youl , Suh Kyung Soo 
Published: April 2005

AbstractTitanium dioxide core and polymer shell composite poly(methyl methacrylate‐co‐n‐butyl acrylate‐co‐methacrylic acid) [P(MMA‐BA‐MAA)] particles were prepared by emulsion copolymerization. The stability of dispersions of TiO2 particles in aqueous solution was investigated. The addition of an ionic surfactant, sodium lauryl sulfate, which can be absorbed strongly at the TiO2/aqueous interface, increases the stability of the TiO2 dispersion effectively by increasing the absolute value of the ζ potential of the TiO2 particles. The adsorption of the nonionic surfactant, Triton X‐100, on the surface of TiO2 particles is less than that of the ionic surfactant. Fourier transform IR spectroscopy was used to measure the content of MAA composite particles. Dynamic light scattering characterized the composite particle size and size distribution. The field‐emission scanning electron microscopy results for the composite particles showed a regular spherical shape, and no bare TiO2 was detected on the entire surface of the samples. The composite particles that were produced showed good spectral reflectance compared to bare TiO2. Thermogravimetric analysis results indicated the encapsulated TiO2 and estimated density of composite particles. There was up to 78.9% encapsulated TiO2 and the density ranged from 1.76 to 1.94 g/cm3. The estimated density of the composite particles is suitable at 1.73 g/cm3, which is due to density matching with the suspending fluid. The sedimentation experiment indicates that reducing the density mismatch between the composite particles and suspending fluid may enhance the stability. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 72–79, 2005
Effect of electron beam irradiation on physical properties of ultrahigh molecular weight polyethylene
Authors: Kim Sungsik , Kang Phil Hyun , Nho Young Chang , Yang O‐Bong 
Published: April 2005

AbstractIf a large amount of polymer radicals remain trapped after the irradiation of ultrahigh molecular weight polyethylene (UHMWPE), the radicals may result in a significant alteration of its physical properties during long‐term shelf storage and implantation. An electron spin resonance spectroscopic study was undertaken to investigate the remaining free radicals in UHMWPE after electron beam irradiation up to 500 kGy in air and an N2 environment. Heat treatment was employed at 110 and 145°C for various periods of time to decay the free radicals. The free radicals were rapidly decayed for 1 h and gradually decayed as a function of time with the heat treatment. The decay of the free radicals was completed more rapidly with a heat treatment at 145°C than at 110°C. Therefore, a longer heat treatment time is required to scavenge all the free radicals formed in UHMWPE at 110°C. The oxidation profiles showed that the oxidation index of the heat‐treated UHMWPE was lower than the oxidation index of the non‐heat‐treated UHMWPE. The heat treatment of irradiated UHMWPE can substantially reduce the concentration of free radicals; therefore, UHMWPE has resistance against long‐term oxidative degradation. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 103–116, 2005
Shrinking rate of conducting grains in HCl–protonated polyaniline, polypyrrole, and polypyrrole/polyaniline blends with their thermal aging
Authors: Sakkopoulos S. , Vitoratos E. , Dalas E. , Kyriakopoulos N. , Malkaj P. , Argyreas T. 
Published: April 2005

AbstractThe dc electrical conductivity (σ) of HCl‐protonated polyaniline, polypyrrole, and their blends was measured from 80 to 300 K for thermal aging times between approximately 0 and 600 h. The thermal aging took place at 70°C under room atmosphere. The change of σ with the temperature (T) and the decrease of σ with the thermal aging time (t) are consistent with a granular metal type structure, in which conductive grains are randomly distributed into an insulating matrix. Aging makes the grains shrink in a corrosion‐like process. From σ = σ(T) measurements the ratio s/d, where s is the average separation between the grains and d their diameter, as well as the rate d(s/d)/dt of their decrease with t were calculated. These revealed that the conductive grains consist of a shell, in which aging proceeds at a decreasing rate, and a central core, which is consumed at a much slower rate. Our measurements not only permitted the estimation of the shell thickness, which lies between 0 and 5 Å, but also gave quantitative information about the quality of the shells and the cores from their aging rates. The shells are consumed with an average rate of d(s/d)/dt = 6.6 × 10−4 (h−1), which is about 5 times greater than the more durable cores. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 117–122, 2005
Efficient circumferential superdrawing
Authors: Aneja Arun Pal 
Published: April 2005

AbstractAmorphous poly(ethylene terephthalate) (PET) can be stretched at low tension without causing any observable crystallization at temperatures above the glass‐transition temperature. The resulting increased length with no measurable change in orientation is called superdrawing. Superdrawing of hollow PET fibers in the circumferential direction was demonstrated earlier. This behavior is accompanied by an increase in fiber voids caused by a combination of air expansion and water permeation. The present work describes efficient techniques for superdrawing in the circumferential direction only. The process develops large void (>65%) fibers starting from standard 15% void spun supply. It is not possible to obtain such large voids in the longitudinal direction in low denier‐per‐filament fibers via direct melt spinning. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 123–127, 2005
Synthesis and properties of polystyrene–clay nanocomposites via in situ intercalative polymerization
Authors: Qi Rongrong , Jin Xing , Nie Jinghui , Yu Wei , Zhou Chixing 
Published: April 2005

AbstractOrganophilic montmorillonite (MMT) was prepared by ion exchange between Na+ ions in the clay and twin benzyldimethyloctadecylammonium bromine cations in an aqueous medium. The organophilic MMT particles were easily dispersed and swollen in styrene monomer. Polystyrene–MMT nanocomposites were prepared by the free‐radical polymerization of styrene containing dispersed clay. The intercalation spacing in the nanocomposites and the degree of dispersion of these composites were investigated with X‐ray diffraction and transmission electron microscopy, respectively. The nanocomposites had higher weight‐average molecular weights, lower glass‐transition temperatures, and better thermal stability (the decomposition temperature was improved by ca. 70°C) than the virgin polystyrene. The rheological behavior of the polystyrene–MMT nanocomposites was also studied. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 201–207, 2005
Scaling phenomena in the growth dynamics of scientific output
Authors: Matia Kaushik , Nunes Amaral Luis A. , Luwel Marc , Moed Henk F. , Stanley H. Eugene 
Published: April 2005

AbstractWe analyze a set of three databases at different levels of aggregation: (a) a database of approximately 106 publications from 247 countries published from 1980–2001, (b) a database of 508 academic institutions from the European Union (EU) and 408 institutes from the United States for the 11‐year period of 1991–2001, and (c) a database of 2,330 Flemish authors published in the period from 1980–2000. At all levels of aggregation we find that the mean annual growth rates of publications is independent of the number of publications of the various units involved. We also find that the standard deviation of the distribution of annual growth rates decays with the number of publications as a power law with exponent ≈ 0.3. These findings are consistent with those of recent studies of systems such as the size of research and development funding budgets of countries, the research publication volumes of U.S. universities, and the size of business firms.
Computational tools for Brassica–Arabidopsis comparative genomics
Authors: Beckett Paul , Bancroft Ian , Trick Martin 
Published: April 2005

AbstractRecent advances, such as the availability of extensive genome survey sequence (GSS) data and draft physical maps, are radically transforming the means by which we can dissect Brassica genome structure and systematically relate it to the Arabidopsis model. Hitherto, our view of the co‐linearities between these closely related genomes had been largely inferred from comparative RFLP data, necessitating substantial interpolation and expert interpretation. Sequencing of the Brassica rapa genome by the Multinational Brassica Genome Project will, however, enable an entirely computational approach to this problem. Meanwhile we have been developing databases and bioinformatics tools to support our work in Brassica comparative genomics, including a recently completed draft physical map of B. rapa integrated with anchor probes derived from the Arabidopsis genome sequence. We are also exploring new ways to display the emerging Brassica–Arabidopsis sequence homology data. We have mapped all publicly available Brassica sequences in silico to the Arabidopsis TIGR v5 genome sequence and published this in the ATIDB database that uses Generic Genome Browser (GBrowse). This in silico approach potentially identifies all paralogous sequences and so we colour‐code the significance of the mappings and offer an integrated, real‐time multiple alignment tool to partition them into paralogous groups. The MySQL database driving GBrowse can also be directly interrogated, using the powerful API offered by the Perl Bio::DB::GFF methods, facilitating a wide range of data‐mining possibilities. Copyright © 2005 John Wiley & Sons, Ltd.
The Korea Brassica Genome Project: A glimpse of the Brassica genome based on comparative genome analysis with Arabidopsis
Authors: Yang Tae‐Jin , Kim Jung‐Sun , Lim Ki‐Byung , Kwon Soo‐Jin , Kim Jin‐A , Jin Mina , Park Jee Young , Lim Myung‐Ho , Kim Ho‐Il , Kim Seog Hyung , Lim Yong Pyo , Park Beom‐Seok 
Published: April 2005

AbstractA complete genome sequence provides unlimited information in the sequenced organism as well as in related taxa. According to the guidance of the Multinational Brassica Genome Project (MBGP), the Korea Brassica Genome Project (KBGP) is sequencing chromosome 1 (cytogenetically oriented chromosome #1) of Brassica rapa. We have selected 48 seed BACs on chromosome 1 using EST genetic markers and FISH analyses. Among them, 30 BAC clones have been sequenced and 18 are on the way. Comparative genome analyses of the EST sequences and sequenced BAC clones from Brassica chromosome 1 revealed their homeologous partner regions on the Arabidopsis genome and a syntenic comparative map between Brassica chromosome 1 and Arabidopsis chromosomes. In silico chromosome walking and clone validation have been successfully applied to extending sequence contigs based on the comparative map and BAC end sequences. In addition, we have defined the (peri)centromeric heterochromatin blocks with centromeric tandem repeats, rDNA and centromeric retrotransposons. In‐depth sequence analyses of five homeologous BAC clones and an Arabidopsis chromosomal region reveal overall co‐linearity, with 82% sequence similarity. The data indicate that the Brassica genome has undergone triplication and subsequent gene losses after the divergence of Arabidopsis and Brassica. Based on in‐depth comparative genome analyses, we propose a comparative genomics approach for conquering the Brassica genome. In 2005 we intend to construct an integrated physical map, including sequence information from 500 BAC clones and integration of fingerprinting data and end sequence data of more than 100 000 BAC clones. The sequences have been submitted to GenBank with accession numbers: 10 204 BAC ends of the KBrH library (CW978640–CW988843); KBrH138P04, AC155338; KBrH117N09, AC155337; KBrH097M21, AC155348; KBrH093K03, AC155347; KBrH081N08, AC155346; KBrH080L24, AC155345; KBrH077A05, AC155343; KBrH020D15, AC155340; KBrH015H17, AC155339; KBrH001H24, AC155335; KBrH080A08, AC155344; KBrH004D11, AC155341; KBrH117M18, AC146875; KBrH052O08, AC155342. Copyright © 2005 John Wiley & Sons, Ltd.
The Tomato Sequencing Project, the first cornerstone of the International Solanaceae Project (SOL)
Authors: Mueller Lukas A. , Tanksley Steven D. , Giovannoni Jim J. , van Eck Joyce , Stack Stephen , Choi Doil , Kim Byung Dong , Chen Mingsheng , Cheng Zhukuan , Li Chuanyou , Ling Hongqing , Xue Yongbiao , Seymour Graham , Bishop Gerard , Bryan Glenn , Sharma Rameshwar , Khurana Jiten , Tyagi Akhilesh , Chattopadhyay Debasis , Singh Nagendra K. , Stiekema Willem , Lindhout P. , Jesse Taco , Lankhorst Rene Klein , Bouzayen Mondher , Shibata Daisuke , Tabata Satoshi , Granell Antonio , Botella Miguel A. , Giuliano Giovanni , Frusciante Luigi , Causse Mathilde , Zamir Dani 
Published: April 2005

AbstractThe genome of tomato (Solanum lycopersicum) is being sequenced by an international consortium of 10 countries (Korea, China, the United Kingdom, India, The Netherlands, France, Japan, Spain, Italy and the United States) as part of a larger initiative called the ‘International Solanaceae Genome Project (SOL): Systems Approach to Diversity and Adaptation’. The goal of this grassroots initiative, launched in November 2003, is to establish a network of information, resources and scientists to ultimately tackle two of the most significant questions in plant biology and agriculture: (1) How can a common set of genes/proteins give rise to a wide range of morphologically and ecologically distinct organisms that occupy our planet? (2) How can a deeper understanding of the genetic basis of plant diversity be harnessed to better meet the needs of society in an environmentally friendly and sustainable manner? The Solanaceae and closely related species such as coffee, which are included in the scope of the SOL project, are ideally suited to address both of these questions. The first step of the SOL project is to use an ordered BAC approach to generate a high quality sequence for the euchromatic portions of the tomato as a reference for the Solanaceae. Due to the high level of macro and micro‐synteny in the Solanaceae the BAC‐by‐BAC tomato sequence will form the framework for shotgun sequencing of other species. The starting point for sequencing the genome is BACs anchored to the genetic map by overgo hybridization and AFLP technology. The overgos are derived from approximately 1500 markers from the tomato high density F2‐2000 genetic map (http://sgn.cornell.edu/). These seed BACs will be used as anchors from which to radiate the tiling path using BAC end sequence data. Annotation will be performed according to SOL project guidelines. All the information generated under the SOL umbrella will be made available in a comprehensive website. The information will be interlinked with the ultimate goal that the comparative biology of the Solanaceae—and beyond—achieves a context that will facilitate a systems biology approach. Copyright © 2005 John Wiley & Sons, Ltd.
Expression of xeroderma pigmentosum A protein predicts improved outcome in metastatic ovarian carcinoma
Authors: Stevens Ellen V. , Raffeld Mark , Espina Virginia , Kristensen Gunnar B. , Trope' Claes G. , Kohn Elise C. , Davidson Ben 
Published: April 2005

AbstractBACKGROUNDThe nucleotide excision repair (NER) proteins repair DNA adducts due to xenobiotics and cancer chemotherapy. The authors hypothesized that expression of the NER protein xeroderma pigmentosum A (XPA) would be reduced in a clinically significant fashion in metastatic ovarian carcinoma.METHODSMalignant effusion specimens were studied so that there was a uniform metastatic ovarian carcinoma population for study. XPA protein expression was analyzed by immunocytochemistry in 142 effusion specimens (109 peritoneal specimens, 33 pleural specimens) from 125 patients. Specimens were obtained at diagnosis (n = 76), and at disease recurrence (n = 66). Patients in the latter group received platinum‐based chemotherapy.RESULTSXPA was expressed in cancer cells in 136 of the 142 (96%) effusion specimens. Strongest expression occurred in leukocytes and reactive mesothelial cells. XPA expression did not correlate with treatment status, effusion site, International Federation of Gynecology and Obstetrics stage, histologic grade, or the extent of residual disease. More effusion tumor cells from patients with a complete response to chemotherapy expressed XPA compared with those with a partial or no response (P = 0.03, χ2 test). Patients with recurrent disease with XPA expressed in > 25% of tumor cells had better progression‐free survival (PFS) by univariate analysis (median = 0 vs. 11 months, P < 0.001; 95% confidence interval [CI], 1–5, 8–14) and overall survival (OS; median = 24 vs. 34 months, P = 0.04; 95% CI, 17–31, 24–44). XPA was the only predictor of PFS outcome by multivariate analysis (P = 0.03).CONCLUSIONSThe results of the current study showed that XPA was widely expressed in metastatic ovarian carcinoma effusion specimens and in the cells of the effusion microenvironment. Paradoxically, XPA expression was associated with better response to chemotherapy and predicted better PFS and OS. Cancer 2005. Published 2005 by the American Cancer Society.
High incidence of disease recurrence in the brain and leptomeninges in patients with nonsmall cell lung carcinoma after response to gefitinib
Authors: Omuro Antonio M. P. , Kris Mark G. , Miller Vincent A. , Franceschi Enrico , Shah Neelam , Milton Daniel T. , Abrey Lauren E. 
Published: April 2005

AbstractBACKGROUNDGefitinib is an epidermal growth factor receptor tyrosine kinase inhibitor that induces an early and dramatic response in 10% of patients with advanced nonsmall cell lung carcinoma (NSCLC). Long‐ term outcome and patterns of disease recurrence after response have not been described.METHODSThe authors evaluated 139 patients with NSCLC treated with gefitinib at Memorial Sloan‐Kettering Cancer Center (New York, NY) between 1998 and 2002. They focused on patterns of disease recurrence, risk of brain metastases (BM) and leptomeningeal metastasis (LM), and long‐term outcome after initial response to gefitinib.RESULTSOf the 139 patients treated with gefitinib, 21 (15%) achieved a partial response. The median age of the responders was 64 years (range, 38–87 years), the median Karnofsky performance score was 80 (range, 60–90), and 4 of the patients were men. All responders had adenocarcinoma. The central nervous system (CNS) was the initial site of disease recurrence in 7 (33%) patients (BM in 5 and LM in 2). In 9 (43%) patients, the initial site of disease recurrence was the lung and in 1 it was the liver and bone. Four (57%) of the patients with disease recurrence in the CNS had lung disease under control. BM also developed in 2 patients who had initial disease recurrence in the lungs. The actuarial 5‐year incidence of CNS metastases was 60%. The median overall survival periods were 15 months and 23 months for patients with and without CNS metastases, respectively (P = 0.24).CONCLUSIONSThe CNS was a frequent site of disease recurrence in patients with NSCLC after an initial response to gefitinib, regardless of disease control in the lungs. Patients should be carefully monitored for neurologic symptoms. Intrinsic resistance of metastatic clones, incomplete CNS penetrance of the drug, and longer survival are possible explanations for this high incidence. Cancer 2005. © 2005 American Cancer Society.