bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and characterization of bioreactive‐end‐group‐containing azoinitiators and their use for preparing end‐functionalized polyvinylpyrrolidone
Authors: Ganachaud F. , Theretz A. , Erout M. N. , Llauro M. F. , Pichot C. 
Published: April 2003

AbstractNew azonitrile initiators carrying N‐hydroxysuccinimide (ACPS) or biotin derivative (ACP‐LC‐B) moieties were synthesized from 4,4′‐azobis(4‐cyanopentanoic acid) (ACPA) with a yield of around 60%. Special care was taken in the assignment of the 13C‐NMR resonances of the ACP‐LC‐B. The kinetic and thermal parameters associated with these initiators were determined by UV spectroscopy and differential scanning calorimetry. The decomposition rate constants (kd) versus temperature are similar for both ACPA and ACPS initiators and are in good agreement with literature data. The activation energies (Ea) values are 132, 140, and 98 kJ mol−1; and the frequency factors are (In A) 34, 35, and 25 for ACPA, ACPS, and ACP‐LC‐B, respectively. Solution polymerization of N‐vinylpyr‐rolidone (NVP) in dimethylformamide initiated with ACPA and ACPS showed similar kinetic behavior with a kp/kt1/2 value of 0.23 (L mol−1 s−1)1/2. This low value and the low molecular weights of the polymers were explained by variations in the initiator efficiencies, as a function of the monomer concentration, as well as by the high chain transfer activity of the solvent. Functionally terminated P(NVP) was evidenced by gel permeation chromatography and an immunoassay test, suggesting that the average number of bioreactive groups per polymer chain was one. © 1995 John Wiley & Sons, Inc.
Synthesis of magnetic polymer microspheres and application for immobilization of proteinase of balillus sublitis
Authors: Li Xiaohong , Sun Zonghua 
Published: April 2003

AbstractCore–shell composite magnetic polymer microspheres, containing a magnetic core and a polymer shell, were synthesized by dispersion copolymerization of styrene (St) and 2‐hydroxyethyl methacrylate (HEMA) in the presence of magnetic oxide (Fe3O4) powder. The Fe3O4 powder was ultrasonically disperesed in poly(ethylene glycol) (PEG) and the affinity between the obtained superfine powder and the monomer and initator was improved. It shows that the dispersion medium and stabilizer system have a great effect on the diameter and dispersion parameter of microspheres. In the condition of controlling polymerization, the magnetic polymer microspheres containing surface OH groups, having 50–500 μm diameter and with better magnetic induction, were synthesized. The proteinase of Balillus sublitis was immobilized on magnetic polymer microspheres with an average diameter of 50–60 μm by covalent coupling. The magnetic immobilized proteinase shows an enzyme activity of 1000 U/g, the enzyme yields are usually 20–30 mg/g of carriers, and the activity retention is about 40%. The stability of the immobilized enzyme was obviously improved. © 1995 John Wiley & Sons, Inc.
Effects of gamma irradiation, gas environments, and postirradiation aging on ultrahigh molecular weight polyethylene
Authors: Deng Meng , Shalaby Shalaby W. 
Published: April 2003

AbstractThe effects of low‐dose (1 to 5 Mrad) gamma irradiation in different gas environments on thermal and tensile properties, and mass of melt‐crystallized ultrahigh molecular weight polyethylene (UHMW‐PE) have been investigated. The gamma irradiation was conducted under four different environments, air, nitrogen, acetylene, and vacuum. Thermal parameters were investigated using differential scanning calorimetry. The results showed that both irradiation dose and environments affected the thermal and tensile properties. Gamma irradiation significantly increased the melting temperature of UHMW‐PE in all cases. However, the oxidation temperatures of irradiated polyethylene was lowered in all cases except those associated with acetylene environment. The crystallinity of the polymer was increased upon irradiation. Tensile yield strength and modulus of irradiated UHMW‐PE increased for all cases except those treated at 1.25 and 2.5 Mrad, and in nitrogen environment that showed a decrease in the modulus. Gamma irradiation caused a weight gain of UHMW‐PE in all conditions. To further the study, the postirradiation aging effect on the irradiated polymer was examined during a period of 1 year, and the results showed that the thermal and tensile properties of UHMW‐PE were, indeed, affected. The data suggests that irradiation in acetylene affects mainly the crosslinking of the polymer. © 1995 John Wiley & Sons, Inc.
Kinetics of reaction of n‐butanol and triaminononane trisisocyanate measured via 13C solution NMR
Authors: Krejsa M. R. , Higginbottom H. P. 
Published: April 2003

AbstractThe model reaction kinetics of a novel trifunctional isocyanate 4‐aminomethyl‐1,8‐diaminooctane [informally referred to as triaminononane trisisocyanate (TTI) with n‐butanol is described. Butanol is used in place of the normal polyols used in actual coatings formulations in order to simplify the system for kinetic analysis. Using 13C‐NMR, the differences in reactivity of each isocyanate group was studied in real‐time measurements. There is little difference in the second‐order rate constants between the three TTI isocyanate groups in the uncatalyzed systems at 25, 35, or 45°C. The dibutyl tin dilaureate (DBTDL) catalyzed system exhibits similar second‐order rate constants for the medium‐and long‐branch systems, and a smaller rate constant for the short‐branch system. The activation energies increase with increasing chain length in the uncatalyzed system, while for the catalyzed system the long and medium branches have identical activation energies, and the short‐branch system has the lowest activation energy. The addition of chloroform or increasing the butanol: TTI ratio results in an increase of the measured rate constant. © 1995 John Wiley & Sons, Inc.
Mechanical and rheological properties of styrene/acrylic gradient polymers
Authors: Jasso Carlos F. , Martinez J. Jesus , Mendizabal E. , Laguna Ovidio 
Published: April 2003

AbstractA butyl acrylate monomer with a small amount of photosensitizer was diffused into a slightly crosslinked polystyrene matrix. After a certain swelling time, the diffusion gradient was either fixed (by rapid photopolymerization in situ) to form a gradient polymer or changed to form an interpenetrating polymer network (IPN), once thermodynamic equilibrium was achieved. Chemical compositions were determined by FTIR. Mechanical and rheological measurements were performed using a universal testing machine and dynamic rheometer, respectively. Impact properties were evaluated with a Falling Dart Impact Tester. Compared to the IPN materials, the gradient polymers exhibit higher moduli, considerable strain, and similar impact resistance. They are also able to retain plastic properties at higher temperatures. Differences in chemical structure of equivalent layers for gradient and IPN polymers yield such differences in properties. © 1995 John Wiley & Sons, Inc.
Ligand sorption kinetics of aromatic amines on new ligand‐exchanger sporopollenin in cobalt ion form
Authors: Vural U. S. , Ersoz M. , Pehlivan E. 
Published: April 2003

AbstractAn approach to study of intraparticle ion‐exchange kinetics of aromatic amines such as p‐chloroaniline, p‐toluidine, and p‐nitroaniline as ligands on Co2+ loaded‐ligand exchanger of sporopollenin (carboxylated epichlorohydrine [CEP]–sporopollenin) is presented and the ligand‐exchange reaction in the resin matrix is shown to be rate‐determining. Kinetic studies of aromatic amines as ligands on the CEP–sporopollenin have been performed using continuous column runs. The observed rate seems to be related to the rate of ligand sorption with the mobile phase (ion) and pH in the aqueous phase. The rate of attainment of equilibrium sorption and breakthrough curves of aromatic amines is seen to be nearly similar. With the sorption mechanism deduced to be dominantly particle diffusion‐controlled, diffusion coefficients determined were found to range from 1.10−8 to 1.0 10−9 cm2s−1. Coupled with the fact that different concentrations of solution were employed, these results may be interpreted as indicating that particle diffusion is the rate‐determining step; on the contrary, film diffusion was not a rate‐controlling step in the ligand‐sorption process under the conditions employed. © 1995 John Wiley & Sons, Inc.
MMSE adaptive array utilizing guard interval in the OFDM systems
Authors: Hori Satoshi , Kikuma Nobuyoshi , Inagaki Naoki 
Published: April 2003

AbstractAn orthogonal frequency division multiplexing (OFDM) transmission system is known to exhibit superior performance compared to a single carrier system in a multipath environment. However, the communication quality degrades severely because of delayed waves exceeding the guard interval and the Doppler shift. To solve this problem, various systems have been proposed that use an adaptive array to suppress undesired signals. In this paper, we propose a system that uses the same signal in the guard interval inserted at the head and the guard interval at the tail of the OFDM effective symbol in an OFDM transmission system and operates a minimum mean square error (MMSE) adaptive array. To clearly show the effectiveness of the proposed system, we analyzed the basic performance by a computer simulation. These results demonstrated excellent operation as an MMSE adaptive array and superior undesired signal suppression. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(10): 1–9, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10121
An adaptive QoS control method in the multichannel communication of the MPEG video data streams
Authors: Ogawa Kentaro , Yamaoka Katsunori , Sakai Yoshinori 
Published: April 2003

AbstractIn a system in which multiple video streams are simultaneously transmitted and restored over a network in real time, QoS control is usually performed individually and end‐to‐end. Thus, the quality of the restored video images varies according to the assigned bandwidth. This paper considers MPEG coding of video images and proposes a method of reducing the variation of image quality by integrated QoS control of video images when multiple video streams share a common channel. More precisely, a scaling method is used in which a bit‐stream scaling method is selected and applied. A band assignment method is also proposed in which image quality degradation is equalized among the streams, based on the property that piecewise‐linear approximation can be applied to the relation between the bit rate and the image quality. A band assignment switching method is proposed for use when the proposed method is applied to the video data streams with frequent scene changes. Quality degradation with an increasing number of streams is discussed. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(10): 66–78, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1177
A method of open system file backup by mainframe
Authors: Takahashi Naoya , Honma Shigeo 
Published: April 2003

AbstractConsolidated disk systems for storing both mainframe files and open system files have been developed in recent years, and the increasingly widespread use of these systems has led to a growing demand for using the mainframe computer with its superior capabilities to back up open system files. The authors propose a method that enables direct access to open system files from a mainframe computer by using existing general‐purpose commands without changing the connection interface with the mainframe. This method not only can achieve equivalent or better performance than the conventional network‐based method and the method of establishing new dedicated input/output commands for accessing open system files at the mainframe side, but also allows various types of existing mainframe backup/restore software to be used directly. This paper describes a backup method for open system files according to the proposed general‐purpose command method and demonstrates that this method is superior to the conventional network‐based method and dedicated command method. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(10): 65–73, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10121
Cell‐transforming activity and mutagenicity of 5 phytoestrogens in cultured mammalian cells
Authors: Tsutsui Takeki , Tamura Yukiko , Yagi Eiichi , Someya Hitomi , Hori Itsuro , Metzler Manfred , Barrett J. Carl 
Published: April 2003

AbstractFor the simultaneous assessment of in vitro carcinogenicity and mutagenicity of phytoestrogens, the abilities of 5 phytoestrogens, daidzein, genistein, biochanin A, prunetin, and coumestrol, to induce cell transformation and genetic effects were examined using the Syrian hamster embryo (SHE) cell model. Cellular growth was inhibited by all phytoestrogens in a concentration‐related manner. The growth inhibitory effect of the compounds was ranked: genistein, prunetin > coumestrol > biochanin A > daidzein, which did not correspond to their apoptosis‐inducing abilities. Morphological transformation in SHE cells was elicited by all phytoestrogens, except, prunetin. The transforming activities were ranked as follows: genistein > coumestrol > daidzein > biochanin A. Somatic mutations in SHE cells at the Na+/K+ ATPase and hprt loci were induced only by genistein, coumestrol, or daidzein. Chromosome aberrations were induced by genistein or coumestrol, and aneuploidy in the near diploid range was occurred by genistein or biochanin A. Genistein, biochanin A or daidzein induced DNA adduct formation in SHE cells with the abilities: genistein > biochanin A > daidzein. Prunetin was negative for any of these genetic endpoints. Our results provide evidence that genistein, coumestrol, daidzein and biochanin A induce cell transformation in SHE cells and that the transforming activities of these phytoestrogens correspond to at least 2 of the mutagenic effects by each phytoestrogen, i.e., gene mutations, chromosome aberrations, aneuploidy or DNA adduct formation, suggesting the possible involvement of mutagenicity in the initiation of phytoestrogen‐induced carcinogenesis. © 2003 Wiley‐Liss, Inc.
Detection and purification of a novel 72 kDa glycoprotein male breast tumor associated antigen
Authors: Basu Aninda , Basu Indranil , Chakraborty Aruna , Pal Soumitro , Chattopadhyay Utpala 
Published: April 2003

AbstractA male breast tumor associated antigen (MBTAA) was purified and partially characterized from human male breast tumor. Three protein peaks were obtained by DEAE‐cellulose column chromatography of a crude extract of human male breast tumor tissues. Circulating antibodies against one of these peaks, MF1, which contained MBTAA, were observed in male breast cancer patients but not in normal male or male patients with carcinoma of other organs (stomach, colon, lung). The MBTAA was partially purified from MF1 by subjecting the fraction to SDS‐PAGE and eluting the protein from band 3 (MB‐3) and by subjecting MF1 to size exclusion‐high performance liquid chromatography (SE‐HPLC). The MBTAA was characterized as a glycoprotein with MW of approximately 72 kDa. It showed no immunological relatedness with TAG‐72, a tumor associated antigen expressed in breast epithelial cells. A 72 kDa protein, immunologically related to MBTAA, was detected and partially purified from female breast tumor. The female breast cancer patients did not have circulating antibodies against this 72 kDa protein or MBTAA. Presence of 72 kDa glycoprotein MBTAA in MF1 and specificity of the anti‐MBTAA antibodies in the sera of male breast cancer patients were further confirmed by Western blot analysis. Absence of anti‐MBTAA antibodies in healthy men and in patients with other cancers suggested that expression of MBTAA may be malignancy‐associated and is highly overexpressed in male breast cancer. © 2003 Wiley‐Liss, Inc.
Dehydroepiandrosterone inhibits the expression of carcinogen‐activating enzymes in vivo
Authors: Ciolino Henry , MacDonald Chistopher , Memon Omar , Dankwah Maame , Chao Yeh Grace 
Published: April 2003

AbstractWe investigated the effect of the steroid hormone dehydroepiandrosterone (DHEA) on the hepatic expression and activity of carcinogen‐activating enzymes, the cytochromes P450 (CYP) 1A1, 1A2 and 1B1, in Sprague‐Dawley rats. In animals fed DHEA at 200 or 400 mg/kg body weight every other day for 2 weeks prior to exposure to the aryl hydrocarbon dimethylbenz[a]anthracene (DMBA, 5 mg/kg), there was a dose‐dependent decrease in hepatic CYP activity, as measured by ethoxyresorufin‐O (EROD) assay, from 37.1 to 22.9 and 14.7 pmoles/min/10 μg microsomes, respectively. DHEA did not directly inhibit microsomal EROD activity, however, leading us to investigate its effects on enzyme expression. To test this, we examined protein and mRNA levels of the enzymes. Western blot for CYP1A1 and CYP1A2 showed that DHEA inhibited the increase in hepatic CYP1A1 and CYP1A2 enzyme levels that are normally induced by DMBA. DMBA‐induced increase in expression of CYP1A1, CYP1A2 and CYP1B1 mRNA was similarly blunted in DHEA‐treated animals. DHEA was also able to significantly reduce the basal expression of CYP1A1 and CYP1A2 but not of CYP1B1. These results indicate that DHEA regulates the expression and, hence, the activity of hepatic carcinogen‐activating enzymes in vivo, and this may be an important mechanism of its chemopreventive activity. Published 2003 Wiley‐Liss, Inc.
Prevention of HER‐2/neu transgenic mammary carcinoma by tamoxifen plus interleukin 12
Authors: Nanni Patrizia , Nicoletti Giordano , De Giovanni Carla , Landuzzi Lorena , Di Carlo Emma , Iezzi Manuela , Ricci Cinzia , Astolfi Annalisa , Croci Stefania , Marangoni Francesco , Musiani Piero , Forni Guido , Lollini Pier‐Luigi 
Published: April 2003

AbstractFVB‐NeuN (N#202) female mice transgenic for the HER‐2/neu protooncogene driven by the murine mammary tumor virus (MMTV) promoter develop mammary carcinomas with a progression from focal atypical hyperplasia to in situ carcinoma and to invasive carcinoma that closely resembles that of human neoplasia. Here we report that the combination of tamoxifen plus interleukin 12 (IL‐12) results in a very effective prevention of mammary carcinogenesis, significantly higher than those obtained with either tamoxifen or IL‐12 alone. At 1 year of age, 20% of control mice resulted tumor‐free, whereas 80% of mice receiving the combined treatment were tumor‐free. At 2 years of age, less than 5% of control mice were tumor‐free, as opposed to 70% of mice treated with tamoxifen plus IL‐12. The combined treatment inhibited mammary carcinogenesis mainly through a reduction in the number of mammary cells at risk of progression, a reduction in estrogen receptors (ERs) expression and a reduction in the angiogenic support to mammary development, likely due to cross‐talk between tamoxifen and interferon‐γ (IFN‐γ) (the main downstream mediator elicited in vivo by IL‐12). The addition of IL‐12 to the tamoxifen treatment more than doubled mouse lifetime and did not exacerbate known side effects of tamoxifen. © 2003 Wiley‐Liss, Inc.
Low sensitivity of retina to AMPA‐induced calcification
Authors: Andrés Noemí , Malpesa Yolanda , Rodríguez Manuel J. , Mahy Nicole 
Published: April 2003

AbstractGlutamate is involved in most CNS neurodegenerative diseases. In particular, retinal diseases such as retinal ischemia, retinitis pigmentosa, and diabetic retinopathy are associated with an excessive synaptic concentration of this neurotransmitter. To gain more insight into retinal excitotoxicity, we carried out a dose–response study in adult rats using α‐amino‐3‐hydroxy‐5‐methylisoxazole‐4‐propionic acid (AMPA), a glutamate analogue. AMPA intraocular injections (between 0.27 and 10.8 nmol) caused no morphologic modification, but a 10.8 + 21 nmol double injection in a 10‐day interval produced a lesion characterized by discrete neuronal loss, astroglial and microglial reactions, and calcium precipitation. Abundant calcium deposits similar to those present in rat and human brain excitotoxicity or hypoxia‐ischemia neurodegeneration were detected by alizarin red staining within the retinal surface and the optic nerve. Glial reactivity, associated normally with astrocytes in the nerve fiber, was assessed in Müller cells. GABA immunoreactivity was detected not only in neuronal elements but also in Müller cells. In contrast to the high vulnerability of the brain to excitotoxin microinjection, AMPA‐induced retinal neurodegeneration may provide a useful model of low central nervous system sensitivity to excitotoxicity. © 2003 Wiley‐Liss, Inc.
Importance of O(3P) atoms and OH radicals in hydrocarbon oxidation during the nonthermal plasma treatment of diesel exhaust inferred using relative‐rate methods
Authors: Hoard John , Wallington Timothy J. , Bretz Richard L. , Malkin Alexander , Dorai Rajesh , Kushner Mark J. 
Published: April 2003

AbstractThe consumption of acetylene and propene during passage of simulated diesel exhaust through a nonthermal plasma at 453 K and atmospheric pressure was studied using experimental and computational techniques. Experimental observations of the relative decay rates of acetylene and propene and computer modeling of the chemical and physical processes in the plasma suggest that O(3P) atoms and, to a lesser extent, OH radicals are the dominant species responsible for initiating hydrocarbon oxidation in this system. Results are discussed in terms of the gas‐phase chemistry occurring during the nonthermal plasma treatment of diesel exhaust. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 35: 231–238, 2003
Kinetic and mechanistic studies of the oxidation of poly(o‐toluidine) doped with 5‐sulfosalicylic acid
Authors: Ahmed Seddique M. 
Published: April 2003

AbstractProtonation of poly(o‐toluidine) base form (POT‐EB) with 5‐sulfosalicylic acid (SSA) was proved experimentally and computationally. Molecular mechanics (MM+) calculations showed that the potential energy (PE) of the optimum molecular geometric structure of SSA‐doped POT is 4.703 × 103 kcal mol−1 or at least three orders of magnitude higher than the PE of the molecular geometric structure of the same matrix. These calculations indicate that the optimization of this matrix is necessary for understanding the stability. Dark green coloration (λ ∼800 nm) after addition of SSA into POT‐EB matrix (dark blue, λ ∼600 nm) revealed that the SSA was working as a protonating agent to convert POT base form (POT‐EB) to salt form (SSA‐doped POT). The change of the dark green color of SSA‐doped POT to dark brown (λ ∼500 nm) after addition of oxidant (K2CrO4) was due to the highest oxidized form of the matrix obtained (the quinoid one), which undergoes a hydrolysis reaction to produce p‐hydroquinone (H2Q) by a mechanism similar to Schiff‐base hydrolysis. Kinetic parameters of the oxidation reaction were deduced employing a computer‐aided kinetic analysis of the absorbance (A) at ∼800 nm against the hydrolysis time (t) data. The results obtained indicate that the rate controlling process may be governed by the Ginstling–Brounshetin equation for three‐dimensional diffusion (D4). The proposed mechanism for the oxidation of SSA‐doped POT matrix is also supported by MM+ calculations. Activation parameters for the rate of the oxidation process of acid‐doped POT matrix have been computed and discussed. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 35: 260–272, 2003
Über kapok‐cellulose
Authors: Zapf von F. 
Published: April 2003

AbstractDie Cellulose des Kapoksamenhaares (Eriodendron infractuosum) wurde schonend isoliert und durch fraktionierte Fällung der polymeranalogen Nitrate deren molekulare Verteilung ermittelt. Die Zusammensetzung der Kapokfaser ist ähnilich der von Holz; auch die molekulare Verteilung ihrer Cellulose gleicht mehr der von Holz als der von Baumwolle. Die hohen Km‐Werte von verdüngen der polymeranalogen Nitrate sind im wesentlichen auf die molekulare Uneinheitlichkeit zurückzuführen.