bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and characterization of modified chitosan microspheres: Effect of the grafting ratio on the controlled release of nifedipine through microspheres
Authors: Kumbar Sangamesh G. , Aminabhavi Tejraj M. 
Published: June 2003

AbstractThe grafting of acrylamide onto a chitosan backbone was carried out at three acrylamide concentrations (polymer/monomer ratio = 1:1, 1:2, and 1:3). The synthesis of the grafted polymer was achieved by K2S2O8‐induced free‐radical polymerization. Microspheres of polyacrylamide‐g‐chitosan crosslinked with glutaraldehyde were prepared to encapsulate nifedipine (NFD), a calcium channel blocker and an antihypertensive drug. The microspheres of polyacrylamide‐g‐chitosan were produced by a water‐in‐oil emulsion technique with three different concentrations of glutaraldehyde as the crosslinking agent. Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) were used to characterize the grafted copolymers, and the microspheres were prepared from them. FTIR and DSC were also used to analyze the extent of crosslinking. The microspheres were characterized by the particle size; the water transport into these microspheres, as well as the equilibrium water uptake, were studied. Scanning electron microscopy confirmed the spherical nature of the particles, which had a mean particle size of 450 μm. Individual particle dynamic swelling experiments suggested that with an increase in crosslinking, the transport became case II. The release of NFD depended on the crosslinking of the network and on the amount of drug loading. Calculating the drug diffusion coefficients with the initial time and later time approximation method further supported this. The drug release in all 27 formulations followed case II transport, and this suggested that the time dependence of the NFD release followed zero‐order kinetics. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2940–2949, 2003
Miscibility studies of epoxy/unsaturated polyester resin blend in chloroform by viscosity, ultrasonic velocity, and refractive index methods
Authors: Rajulu A. Varada , Devi L. Ganga , Rao G. Babu 
Published: June 2003

AbstractMiscibility studies of blends of epoxy with unsaturated polyester resin in chloroform were carried out by viscosity, ultrasonic velocity, and refractive methods at 30°C. By using viscosity data, the interaction parameters were computed, which indicated that epoxy/unsaturated polyester resin blends were miscible. The miscibility was further confirmed by the ultrasonic velocity and refractive index methods. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2970–2972, 2003
Phosphorylated cation‐exchangers from cotton stalks and their constituents
Authors: Nada Abd‐Allah M. A. , Hassan Mohammad L. 
Published: June 2003

AbstractCation‐exchangers were prepared by phosphorylation of cotton stalks and their isolated constituents (lignin, soda‐anthraquinone pulp, and bleached cellulose pulp). FTIR spectra of the phosphorylated materials showed new absorption bands at 950–1200 cm−1 of the COP bonds as a result of phosphorylation. The adsorption of different heavy metal ions (lead, copper, nickel, cobalt, chromium, and cadmium) at different metal ion concentrations (50–1500 μg) by the phosphorylated cotton stalks was studied. The adsorption of metal ions by the phosphorylated cotton stalks increased by increasing their concentration. The binding capacity of phosphorylated cellulose, lignin, and soda‐anthraquinone pulp was measured at 1000 μg metal ion concentration. The adsorption of the different heavy metal ions by phosphorylated‐lignin and ‐bleached cellulose pulp was higher than that of phosphorylated cotton stalks. Thermogravimetric analysis of the raw and phosphorylated cotton stalks showed that the resistance of the phosphorylated cotton stalks to thermal degradation was higher than that of raw cotton stalks (lower rate of weight loss), despite the lower degradation onset temperature of the phosphorylated cotton stalks. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2950–2956, 2003
Structure and properties of ultraviolet‐irradiated high density polyethylene at different environmental temperatures
Authors: Wu Shishan , Xu Xi 
Published: June 2003

AbstractCO, CO, and C(O)O oxygen‐containing groups were introduced onto the molecular chain of high‐density polyethylene (HDPE) through ultraviolet irradiation in air. The introduction rate of the oxygen‐containing groups onto HDPE increased with increasing environmental temperature. After ultraviolet irradiation, the molecular weight of HDPE decreased, and its distribution became wider; the melting temperature, contact angle with water, and impact strength decreased; the degree of crystallinity and yield strength increased; and their variation amplitude increased with environmental temperature. The environmental temperature had an effect on the gel content of irradiated HDPE. HDPE‐irradiated for 48 h at 35° and 50°C were not crosslinked. However, gelation took place in HDPE irradiated for 24 h at 70°C. HDPE irradiated at a high environmental temperature was more effective than that irradiated at a low environmental temperature in compatibilizing HDPE with PVA. Compared with the 83/17 HDPE/PVA blend, the yield and notched impact strength of the 73/17 HDPE/PVA blend compatibilized with 10% HDPE irradiated for 24 h at an environmental temperature of 70°C increased from 30.8 MPa and 110 J/m to 34.9 MPa and 142 J/m, respectively. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2966–2969, 2003
Postfunctionalization strategy for developing polyphosphazene with a high loading of highly polar molecules in the side arms
Authors: Li Zhen , Qin Jingui , Tang Hongding , Liu Yunyang 
Published: June 2003

AbstractA new postfunctionalization strategy for developing polyphosphazene functionalized with a high density of highly polar molecules was explored, and the moiety loading was up to 0.84 per unit. A polyphosphazene with N,N‐dialkyl‐substituted aniline as side chains was first synthesized by a direct substituted reaction, and then post azo coupling of p‐nitrobenzenediazonium fluoroborate toward the aniline groups afforded functionalized polyphosphazenes with highly polar molecules. The structural characterization was performed with 1H‐NMR, IR, and ultraviolet–visible spectroscopy and gel permeation chromatography. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2989–2993, 2003
Crosslinked acrylic pressure‐sensitive adhesives. II. Effect of humidity on the crosslinking reaction
Authors: Asahara Junko , Sano Ayako , Hori Naruhito , Takemura Akio , Ono Hirokuni 
Published: June 2003

AbstractThe effect of humidity during storage on the crosslinking reactions of isocyanate groups was investigated with attenuated total reflectance Fourier transform infrared spectroscopy with pressure‐sensitive adhesives composed of poly[ethyl acrylate‐co‐(2‐ethylhexyl acrylate)‐co‐(2‐hydroxyethyl methacrylate)] as a base resin and polyisocyanate as a crosslinker. A peak‐resolving analysis of the amide II region revealed four bands. According to an analysis of the Fourier transform infrared spectra of the model compounds, these four bands were assigned to free urethane linkages, hydrogen‐bonded urethane linkages, free urea linkages, and hydrogen‐bonded urea linkages. As expected, storage under humid conditions led to the formation of free and hydrogen‐bonded urea linkages corresponding to the promotion of isocyanate consumption. Peak resolution of the amide II region was found to be a reasonable way of monitoring urethane and urea linkages during crosslinking reactions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3039–3045, 2003
Phase separation and melting behavior in poly(ε‐caprolactone)‐epoxy blends cured by 3,3′‐dimethylmethylene‐di(cyclohexylamine)
Authors: Chen Jyh‐Luen , Chang Feng‐Chih 
Published: June 2003

AbstractThe morphology and the melting behavior of poly(ε‐caprolactone)/epoxy blends (PCL/epoxy) have been investigated by SEM and DSC. The mechanism of phase separation varies with the curing temperature and PCL content, which can be deduced from the cured morphology of the blend. Higher temperature leads to lower blend viscosity and a higher curing rate, and the final morphology is determined by the competition of these two factors. The PCL melting behavior of the blend is influenced by the extent of phase separation and crystallization during curing. The dual melting behavior of the PCL blend can be ascribed to the interference of the epoxy, which results in the formation of less perfect PCL crystallites melted at lower temperature. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3107–3114, 2003
Resolution of 1‐ and 2‐naphthylmethoxyacetic acids, NMR reagents for absolute configuration determination, by use of L‐phenylalaninol
Authors: Arita Shoko , Yabuuchi Tetsuya , Kusumi Takenori 
Published: June 2003

AbstractRacemic 1‐ and 2‐naphthylmethoxyacetic acids (1NMA and 2NMA), the chiral anisotropic reagents used for absolute configuration determination of chiral secondary alcohols and primary amines, were conveniently resolved to enantiomers (>99% ee) by condensation with L‐phenylalaninol (2‐amino‐3‐phenylpropanol), chromatographic separation of the diastereomers, and hydrolysis. This method enables large‐scale preparation of enantiomeric 1NMA and 2NMA. Chirality 15:609–614, 2003. © 2003 Wiley‐Liss, Inc.
Conformational spaces of Cinchona alkaloids
Authors: Caner Hava , Biedermann P. Ulrich , Agranat Israel 
Published: June 2003

AbstractA systematic and comprehensive study of the conformational spaces of the Cinchona alkaloids quinine, quinidine, cinchonine, cinchonidine, epiquinine, epiquinidine, epicinchonine, and epicinchonidine using the semiempirical PM3 method is described. The results were analyzed in terms of syn/anti and open/closed/hindered and α/β/γ conformations. Special emphasis was given to the torsion angles T1 (C4a′‐C4′‐C9‐C8), T2 (C4′‐C9‐C8‐N1) and T3 (H‐O9‐C9‐C8) that define the backbone and the hydroxy conformation, respectively. The results reveal the quasi‐enantiomeric relationships between quinine and quinidine and between epiquinine and epiquinidine, and the main structural differences that exist between the therapeutically active Cinchona alkaloids, quinine and quinidine, and their inactive epimers, epiquinine and epiquinidine. The lowest energy conformation of quinine and quinidine is anti‐closed‐α. The lowest energy conformations of epiquinine and epiquinidine are anti‐open‐β and anti‐open‐α, respectively. Low energy conformations with an intramolecular hydrogen bond (N1. . .H. . .O9) were found in epiquinine (the global minimum) and epiquinidine, but not in quinine and quinidine. Chirality 15:637–645, 2003. © 2003 Wiley‐Liss, Inc.
Stereoselective single‐dose kinetics of citalopram and its metabolites in rats
Authors: Kugelberg Fredrik C. , Carlsson Björn , Ahlner Johan , Bengtsson Finn 
Published: June 2003

AbstractThe single‐dose kinetics of the enantiomers of citalopram (CIT) and its metabolites, demethylcitalopram (DCIT) and didemethylcitalopram (DDCIT), were investigated after administration of 10, 20, or 100 mg/kg (s.c.) rac‐CIT to rats. Samples from serum and two brain regions were collected 1, 3, 10, or 20 h postdose for HPLC analysis. In the 100 mg/kg rats, the enantiomeric (S/R) serum concentration ratios of CIT decreased during the study period (0.93 at 1 h vs. 0.59 at 20 h; P < 0.001). In the 10 and 20 mg/kg rats, the decrease in serum S/R CIT ratios was not so evident as in the 100 mg/kg rats. In all three groups the S/R CIT ratio was almost the same in the brain as in serum, although both CIT enantiomer levels in the brain were found to be 5–10 times higher than the levels in serum. The serum and brain metabolite levels were low in the 10 and 20 mg/kg rats, whereas the levels increased during the study period in the 100 mg/kg rats. In conclusion, the CIT enantiomers were shown for the first time to be stereoselectively metabolized after single‐dose administration to rats, as previously shown in steady‐state dosing studies in humans and rats. Chirality 15:622–629, 2003. © 2003 Wiley‐Liss, Inc.
Examination of a fault current limiter with conduction‐cooled Nb3Sn screen
Authors: Sasaki Ken‐Ichi , Yamagata Akira , Onishi Toshitada 
Published: June 2003

AbstractWe examined the possibility of the practical use of a conduction‐cooled magnetic shield type fault current limiter. A small superconducting fault current limiter was built and the current limiting characteristics were tested. Conceptual design of the conduction‐cooled fault current limiter for a distribution power system was carried out, and we calculated and discussed the temperature rise of shielding coil during a normal and a fault condition. We suggest a protection method for quench due to local disturbances during normal operation. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 145(1): 20–27, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10164
A new three‐input/output characteristic‐varying filter in the D‐module for direct processing of three‐phase signals
Authors: Shinnaka Shinji 
Published: June 2003

AbstractThis paper proposes a new three‐input and three‐output characteristic‐varying filter in the D‐module for direct processing of three‐phase signals, which are becoming indispensable for effective active compensation of three‐phase power such as harmonics current, negative phase current, reactive power, and varying voltage compensations. The filter in the D‐module can show different filtering characteristics to positive, negative, and zero phase components of three‐phase signals and can allow direct processing of the signals based on frequency polarities. The filter in the D‐module can also change dynamically its filtering characteristics by simply injecting a shift‐signal to itself. These filtering effects are obtained in a very simple manner using the D‐module. A new unified analysis of attractive general characteristics of the proposed filter in the D‐module is given for its easy designs and realizations as well. Effectiveness of the analysis and usefulness of the filter in the D‐module are newly examined and confirmed through experiments. The newly proposed filter in the D‐module has potential regarding a variety of three‐phase signal filtering applications. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 145(1): 28–38, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10170
Proper decision for maintenance intervals of equipment in thermal power station based on operational rate and maintenance replacement rate
Authors: Katafuchi Tatsuro , Nakamura Masatoshi , Suzuki Yoshihiro , Hatazaki Hironori 
Published: June 2003

AbstractIn this paper, a rational method has been proposed to determine the maintenance schedule of turbines in thermal power stations. Due to the fact that many failure data do not exist, we focused on the maintenance replacement rate, and the dimensional reduction method was used. The proper maintenance interval based on the future operational rate was chosen by the relationship between the operational rate and the maintenance interval. The results of analysis have shown a reduction in the maintenance cost, while maintaining the current reliability. The proposed method was implemented by Kyushu Electric Power Co. beginning in April 2002 to determine the maintenance schedule of turbines in thermal power stations. Moreover, it can be applied to any other system. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 145(1): 10–19, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10194
Signal enhancement in multiuser communication through adaptivity on transmit
Authors: Medouri Abdellatif , Sarkar Tapan S. 
Published: June 2003

AbstractThis paper presents a technique to enhance the received signals in a multiuser communication environment through the use of adaptivity on transmit. This technique is based on the principle of reciprocity and is independent of the material medium of transmission and the near‐field environments. The objective here is to select a set of weights to be applied to each transmitting antenna, which is a function of the user location. The methodology is not a function of the multipath environment. Furthermore, the transmitted signal may be directed to a particular receiver location and simultaneously be minimized at other receiver locations while operating on the same frequency. Numerical simulations have been made to illustrate the novelty of the proposed approach. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 265–269, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11034
Reception of an oblique electromagnetic plane wave by a linear‐wire antenna: A time domain analysis
Authors: Sagnard F. , Uguen B. , El Zein G. 
Published: June 2003

AbstractAn analytic formulation to study the reception process, at an oblique angle of incidence, of a linear‐wire antenna excited by a transient short signal is proposed. The current, the charge components, and the scattered electric field are computed in the time domain. This modeling leads to a consistent parametric study which is a first and useful step for the development of an ultra‐wide bandwidth (UWB) communication system. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 281–291, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11039
Novel metal‐plate antenna for WLAN application
Authors: Yeh Shih‐Huang , Lin Chia‐Ching , Chang Fa‐Shian , Wong Kin‐Lu 
Published: June 2003

AbstractA novel metal‐plate antenna easily constructed by folding a single metal plate is proposed. The antenna comprises a radiating portion, a vertical ground portion, and a horizontal ground portion, and is easily fed by using a 50Ω coaxial line. A constructed prototype suitable for application in the 2.4‐GHz WLAN band is demonstrated. Details of the proposed antenna design are described, and experimental results of the constructed prototype are presented. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 291–293, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11040
A new probe‐excited dual‐mode cavity filter
Authors: Leng Karen Goh Hui , Shen Zhongxiang , Khong Andy 
Published: June 2003

AbstractThis paper presents a novel configuration for dual‐mode cylindrical cavity filters operating in the TE111 mode. The proposed configuration is compact yet simple, with only one coupling probe to excite two orthogonal TE111 modes in a cylindrical waveguide cavity. A prototype is designed to operate at 10 GHz. Simulated and experimental results are provided. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 335–337, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11053
Soluble Fas (FasB) regulates luteal cell apoptosis during luteolysis in murine ovaries
Authors: Komatsu Kohji , Manabe Noboru , Kiso Minako , Shimabe Munetake , Miyamoto Hajime 
Published: June 2003

AbstractDuring luteolysis, luteal cell apoptosis is induced by the Fas ligand (FasL)/Fas system. In murine luteal bodies, we demonstrated the expression of mRNA of soluble form of Fas (FasB), which binds to FasL and prevents apoptosis induction. By in situ hybridization, strong expression of FasB mRNA was observed in normal luteal bodies, in which no apoptotic cells were detected, but negative/trace expression in regressing luteal bodies, in which many apoptotic cells were observed. Immunohistochemical staining revealed that Fas and TNF‐α were localized in both normal and regressing luteal bodies, but IFN‐γ was localized only in regressing luteal bodies. Apoptosis was induced in primary cultured luteal cells, when they were pretreated with TNF‐α and IFN‐γ and then incubated with TNF‐α, IFN‐γ, and mouse recombinant FasL (rFasL). However, no apoptosis was detected in the cells, when they were treated with rFasL alone, TNF‐α alone, IFN‐γ alone, TNF‐α and rFasL, IFN‐γ and rFasL, or TNF‐α and IFN‐γ. Fas mRNA expression in cultured luteal cells was up‐regulated by the treatment of TNF‐α, IFN‐γ, or TNF‐α and IFN‐γ. The expression of FasB mRNA was down‐regulated, when the cells were treated with TNF‐α and IFN‐γ, but its expression was not changed by the treatment of TNF‐α alone or IFN‐γ alone. We conclude that FasB inhibits the apoptosis induction in luteal cells of normal luteal bodies, and that decreased FasB production induced by TNF‐α and IFN‐γ made possible the apoptosis induction in the luteal cells of regressing luteal bodies. Mol. Reprod. Dev. 65: 345–352, 2003. © 2003 Wiley‐Liss, Inc.
Roles of the conserved CCAAT and GC boxes of the human and mouse type II transforming growth factor‐β receptor genes
Authors: Bernadt Cory T. , Rizzino Angie 
Published: June 2003

AbstractEmbryonal carcinoma (EC) cells are used widely to study the molecular mechanisms that regulate the transcription of genes during mammalian embryogenesis. The type II transforming growth factor‐β receptor (TβR‐II) gene is expressed at very low levels by mouse EC cells prior to differentiation. Differentiation of EC cells results in increases of both the steady‐state levels of TβR‐II mRNA and the activity of the TβR‐II promoter. Several cis‐regulatory elements have been shown previously to regulate the TβR‐II gene. This study focuses on the role of a CCAAT box and three GC boxes in the regulation of the human and mouse TβR‐II promoters in EC‐differentiated cells. We demonstrate that the CCAAT box and two flanking GC boxes, Sp A and Sp B, function as positive regulatory elements in the human TβR‐II promoter, and that the transcription factor complex NF‐Y positively regulates the human TβR‐II promoter through the CCAAT box motif. We also show that the CCAAT box and the downstream GC box Sp B, which are conserved between the human and mouse promoters, behave as positive regulatory elements in the mouse TβR‐II promoter. In addition, we demonstrate that the transcription factor Sp1 can bind to the Sp B GC box in vitro. Finally, we show that a GC box located 25 bp upstream of the major transcription start site of the TβR‐II gene plays a minimal role in the function of the TβR‐II promoter in EC‐differentiated cells. Together, our studies highlight important differences and similarities in the cis‐regulatory elements that regulate the human and mouse TβR‐II promoters. Mol. Reprod. Dev. 65: 353–365, 2003. © 2003 Wiley‐Liss, Inc.
Molecular cloning and endometrial expression of porcine amphiregulin
Authors: Kim Jong G. , Vallet Jeffrey L. , Christenson Ronald K. 
Published: June 2003

AbstractThe porcine amphiregulin gene was previously reported to be within the quantitative trait locus (QTL) for uterine capacity on chromosome 8. Because amphiregulin stimulates cell proliferation, the amphiregulin gene might be responsible for this QTL. The objectives of this study were to clone amphiregulin cDNA and compare endometrial expression of its mRNA in pregnant Meishan (M) and White composite (WC) pigs. We obtained two amphiregulin cDNAs, one with 1,221 bp and another with 1,109 bp. The 112 bp difference corresponded to exon 5 of the human amphiregulin gene, which codes for the cytoplasmic domain. Endometrial mRNA expression of amphiregulin was significantly lower in M pigs than in WC pigs during early pregnancy (day 15–40 of gestation). Amphiregulin mRNA expression in the endometrium of both M and WC pigs increased (P < 0.01) from days 15 to 20, decreased (P = 0.01) from days 20 to 30, and did not change between days 30 and 40. This may result in reduced amphiregulin protein production leading to the slower development of M conceptuses, contributing to greater uterine capacity and litter size in prolific Chinese M pigs. Porcine genomic sequences isolated from a bacterial artificial chromosome genomic library contained exon 5, suggesting that the deletion of exon 5 in the mRNA may be due to differential splicing. The amphiregulin gene consisted of six exons and five introns spanning 10.3 kb. Mol. Reprod. Dev. 65: 366–372, 2003. © 2003 Wiley‐Liss, Inc.