bluuebunny/crossref_metadata_2025 huggingface dataset:
Melt polymerization of bisphenol‐A and diphenyl carbonate in a semibatch reactor
Authors: Woo Boo‐Gon , Choi Kyu Yong , Song Kwang Ho , Lee Sang Ho
Published: August 2002

The effect of thermodynamic phase equilibrium on the kinetics of semibatch melt polycondensation of bisphenol‐A and diphenyl carbonate was studied for the synthesis of polycarbonate. In the melt‐polymerization process, a partial loss of diphenyl carbonate occurs as the reaction by‐product phenol is removed from the reactor. To obtain a high molecular weight polymer under high temperature and low‐pressure conditions, a stoichiometric mol ratio of the two reactive end groups needs to be maintained during the polymerization. In this work, vapor–liquid equilibrium data for a binary mixture of phenol and diphenyl carbonate are reported and they are used in conjunction with the Wilson equation to calculate the exact amounts of diphenyl carbonate and phenol returned from a reflux column to the reactor. A good agreement between the reactor model simulations and the experimental polymerization data was obtained. It was also observed that diphenyl carbonate is quickly consumed during the early stage of polymerization and the fraction of evaporated diphenyl carbonate refluxed to the reactor is essentially constant during this period. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1253–1266, 2001
Evaluation of the permeability and blood‐compatibility properties of membranes formed by physical interpenetration of chitosan with PEO/PPO/PEO triblock copolymers
Authors: Anderson Derick , Nguyen Tragiang , Lai Phung‐Kim , Amiji Mansoor
Published: August 2002

In order to develop blood compatible membranes with controlled porosity, we have fabricated and examined the properties of physical interpenetrating network (PIN) of chitosan and poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) (PEO/PPO/PEO) triblock copolymers (Pluronics®). Degree of equilibrium swelling, scanning electron microscopy, and electron spectroscopy for chemical analysis (ESCA) were used to characterize the bulk and surface properties. Vitamin B12 and human serum albumin were used as permeability markers. Platelet adhesion and activation were used to determine the blood‐interaction properties of the PIN membranes. Unlike chitosan membranes that were nonporous, the chitosan‐Pluronic PIN membranes were highly porous with the pore size, depending on the type of incorporated Pluronic polyol. ESCA results showed a significant increase in the CO signal of C1s spectra on the PIN membranes that correlates with the presence of PEO chains on the surface. The permeability coefficients of vitamin B12 and albumin were higher in the chitosan‐Pluronic PIN membranes than in the control. The number of adherent platelets and the extent of activation were significantly reduced on the chitosan‐Pluronic PIN membranes. The decrease in platelet adhesion and activation correlated positively with the PEO chain length of the incorporated Pluronic polyols. The results of this study show that chitosan‐Pluronic PIN membranes offer a blood‐compatible alternative with a higher‐molecular‐weight cutoff for use in hemodialysis and related applications. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1274–1284, 2001
Use of the unique properties of fluoropolymers in the design of new, highly effective, ecologically friendly technologies for the fine purification of hydrogen halides and their aqueous solutions
Authors: Blum G. Z. , Ryabenko E. A. , Yaroshenko A. M. , Zaikov G. E. , Zaikov V. G.
Published: August 2002

A number of properties of fluoropolymers in aqueous solutions of hydrogen halides were investigated. The results enable fluoropolymers to be used in the purification of hydrogen halides and their aqueous solutions. The hydrophobicity of fluoropolymers and their diffusion permeability enable production of hydrogen halides of low moisture content. A second unit for hydroionic convection is based on hydroionic repulsion (determined by the hydrophobic properties of the fluoropolymer) and ionic elimination. The two units enable the highly effective, ecologically safe manufacture of highly pure hydrogen halides and their aqueous solutions to be carried out with minimum feedstock, cooling water, and power consumption. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1383–1387, 2001
Gas and water transport properties of epoxy–amine networks: Influence of crosslink density
Authors: Damian Catherine , Escoubes Marielle , Espuche Eliane
Published: August 2002

The gas and water transport properties were studied on seven epoxy–amine networks that differ by their di/mono epoxy composition and their cure cycle. The characteristic parameters of transport M∞ and D were determined in each case, and they show that the solubility and diffusion coefficients are influenced by their composition. The solubility increases with the extend of cure and with the decrease of dangling chains, and in both cases the evolution of the diffusivity is inverse. The variations of the solubility and diffusivity have been discussed as a function of two parameters: polar groups and unrelaxed holes of the glassy networks. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2058–2066, 2001
Unusual rheological behaviors of linear PE and PE/kaolin composite
Authors: Wu Qiye , Wang Xin , Gao Weiping , Hu Youliang , Qi Zongneng
Published: August 2002

The unusual flow behaviors of linear PE melts are caused by high molecular weight, tight entanglements of molecular chains, and strong adsorption of the melt at the capillary wall. Especially, the extreme change of interface adsorption is followed by an unusual flow, and at the molecular level, the dynamic variety of entanglement and disentanglement between the adsorption chain near the wall and the nonadsorption chain is the cause of the extrusion pressure vibration. Ultrahigh molecular weight polyethylene (UHMWPE)/kaolin composites prepared by polymerization filling could be smoothly extruded through the capillary. Also, with increase of the kaolin content, the apparent viscosity of the composite decreased and the processability was improved. Under slip boundary conditions, the real shear rate and shear stress of the melt near the capillary wall were reduced. The viscosity descent (desorption) and the deformation energy decrease of the melt near the wall were the important preconditions to gain a steady flow in a second glossy zone. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2154–2161, 2001
Synthesis and dispersion copolymerization of poly(2‐methyl‐2‐oxazoline) macromers with cinnamoyl end groups
Authors: David Geta , Ioanid Aurelia
Published: August 2002

Poly(2‐methyl‐2‐oxazoline) (PMOZO) macromers bearing cinnamoyl functional groups were synthesized either by utilizing the end‐capping method of growing PMOZO living chains with cinnamic acid or by coupling glycolic PMOZO telomers with cinnamoyl chloride. The first approach was proved to be more efficient and convenient, giving rise easier to a quantitative functionalization. Dispersion copolymerization of styrene with the resulted macromers in an ethanol–water system has been studied in order to obtain monodisperse micrometer size beads. The effect of some variables, such as macromer dimension and concentration, initiator type, alcohol/water ratio, on conversion, particle size and size distribution was investigated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2191–2199, 2001
Copolymerization of methylmethacrylate with styrene using triphenylbismuthoniumylide as radical initiator
Authors: Bajpai Radha , Srivastava A. K.
Published: August 2002

Bismuthoniumylide‐initiated radical copolymerization of methylmethacrylate with styrene at 60 ± 0.2°C using dioxane as an inert solvent, follows ideal kinetics (Rp ∝ [ylide]0.5 [MMA]1.0 [sty]1.0), and yields alternating copolymer as evident from NMR spectroscopy. The values of reactivity ratios r1 and r2, calculated from Finemann–Ross method are 0.48 and 0.45, respectively. The system follows ternary molecular complex mechanism. The radical mode of polymerization has been confirmed by ESR spectroscopy and the effect of hydroquinone. The value of activation energy and k/kt are 65.0 KJ mol−1 and 2.5 × 10−5 l mole−1 s−1, respectively. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2774–2781, 2001
Study on tribological properties of frictional material based aromatic polyamide
Authors: Liu Xujun , Li Tongsheng , Tian Nong , Liu Weimin
Published: August 2002

The effect of inorganic fillers on the friction and wear behavior of frictional material based poly(m‐phenylene isophthalamide) (PMIA) is investigated. The polymer composites are prepared by compression molding. The friction and wear of PMIA composites are investigated on a block‐on‐ring machine by running the PMIA composite block against plain carbon steel. The morphologies of the worn surface of PMIA composite and the ring counterface are examined by using electron probe microanalysis. It is found that copper compounds including CuCl, CuCl2, Cu2O, and CuO filled PMIA exhibit considerably higher friction coefficient than unfilled PMIA, while the wear rate of those composites decrease. Especially, CuCl is the optimal filler in the copper compounds investigated above. The filled PMIA composite containing CuCl, graphite, and short carbon fiber shows the best properties for frictional material. The friction coefficient of CuCl–PMIA composite is higher than that of unfilled PMIA because of the abrasive action of CuCl particle. It is probably the smoother surface of counterpart ring and composite block that resulted in the lower wear rate and friction coefficient of PMIA composite. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2790–2794, 2001
Miscibility study of cellulose acetate/carboxylated poly(vinyl chloride) blend in cyclohexanone by viscosity, ultrasonic velocity, refractive index, and polarizing microscopic methods
Authors: Rajulu A. Varada , Reddy R. Lakshminarayana , Rao G. Babu , He Jiasong , Zhang Jun
Published: August 2002

The viscosity, ultrasonic velocity, refractive index, and density of cellulose acetate/carboxylated poly(vinyl chloride) (CA/C‐PVC) blends in cyclohexanone, a common solvent, were measured at 30°C. After casting films of the blend for a 50:50 composition, polarizing micrographs were taken. Using the viscosity data, the interaction parameters were computed by employing two different equations. These values indicated that the CA/C‐PVC blend is miscible. This was confirmed by ultrasonic, refractive index, density, and polarizing microscopic methods. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 557–561, 2001
Oxidative destruction of chitosan under the effect of ozone and hydrogen peroxide
Authors: Kabal'Nova N. N. , Murinov K. Yu. , Mullagaliev I. R. , Krasnogorskaya N. N. , Shereshovets V. V. , Monakov Yu. B. , Zaikov G. E.
Published: August 2002

In the present work the results of the study of oxidative destruction of chitosan effected by ozone and hydrogen peroxide are listed. The results obtained verify the rupture of 1,4‐β‐D‐glucoside bonds in macromolecule to be the basic process during amino groups of chitosan protection by acids. The rate of ozone with chitosan interaction depends on the concentration of ions in reaction mass. Destruction of chitosan by hydrogen peroxide leads to the formation of oligosaccharides in contrast to ozonolysis. Hydrogen peroxide oxidizes functional groups of chitosan only under tough conditions. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 875–881, 2001
Characterization of poly(vinylpyrrolidone)–konjac glucomannan blend films
Authors: Xiao Chaobo , Liu Hongjuan , Lu Yongshang , Zhang Lina
Published: August 2002

Blend films of konjac glucomannan (KGM) and poly(vinylpyrrolidone) (PVP) were prepared by using a conventional solvent‐casting technique and dried at room temperature. The structure and physical properties were studied by infrared spectroscopy (IR), wide‐angle X‐ray diffraction (WAXD), thermogravimetric analysis (TGA), differential thermal analysis (DTA), scanning electron microscope (SEM), and by measurement of mechanical properties. The changes of carbonyl stretching bands of KGM and PVP and hydroxyl stretching region of KGM were detected by FTIR analysis. WAXD analysis revealed that the film KP‐2 got the lowest crystallinity of all the films. The tensile strength and breaking elongation of the blend films reaches the maximum value at 10 wt % PVP content. The DTA curves indicated the existence of interaction between two kinds of macromolecules. Higher thermal stability was attained by konjac glucomannan through blending with PVP. These improvements are attributable to the existence of a certain degree of interaction between KGM and PVP molecules resulted from intermolecular hydrogen bonds. Air surface morphology of the films observed by SEM was consistent with the results mentioned above. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1049–1055, 2001
Poly(2,3‐dimethylaniline) as a competent material for humidity sensor
Authors: Kulkarni Milind V. , Athawale Anjali A.
Published: August 2002

Chemically synthesized polyaniline and its ring substituted derivatives such as poly(o‐toluidine), poly(2,3‐dimethylaniline) and poly(2,5‐dimethylaniline) were utilized as sensors for relative humidity (RH) between 6.4% and 97.3%. The conductivity of the polymers was found to decrease on exposure to RH between 6.4% and 75.3%. However, in presence of 97.3% RH the conductivity was seen to increase. A comparison of the observed results reveals that, though each of the polymers responds to various percentages of RH, poly(2,3‐dimethylaniline) shows the best response in terms of sensitivity and linear range. The percent sensitivity was found to be greater for poly(2,3‐dimethylaniline) than that for polyaniline. The observed change in conductivity as well as the degree of change in magnitude of conductivity in the polymers was supported by X‐ray diffraction studies and IR spectroscopy. The X‐ray analysis showed that crystallinity of the polymer changed both in the presence and the absence of a specific percent of RH. Similarly, the IR spectra exhibited variation in the peak intensities of the O—H and >N–H groups. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1382–1387, 2001
Influence of retention system and curing on paper wet strength improvement by a copolymer containing glycidyl groups
Authors: Zhang Xiumei , Tanaka Hiroo
Published: August 2002

The copolymer (PGS) synthesized by polymerization of glycidyl methacrylate with styrene had a significant effect on paper wet strength. Factors such as retention aids, curing temperature, and curing time were investigated. The results showed that among four kinds of partially aminated poly N‐vinylformamide (APNVF), APNVF‐4 that had the highest charge density was the most effective for strengthening paper. The effectiveness of the retention systems increased with their wet functionality in the order APNVF‐4 > C‐PAM ≈ PAAm > PEI > PDADMAC. The curing temperature and curing time had little influence on paper dry strength, but they influenced paper wet strength greatly. The FTIR studies on model reactions showed that glycidyl groups could react with amino groups and carboxyl groups under common curing conditions. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2791–2797, 2001
Influence of isomer ratio and ring substituents in decomposition activation energies of α,α,α′,α′‐tetrasubstituted dibenzyls
Authors: Qi Chenze , Hu Youhua , Ji Genzhong , Liu Weimin , Yan Fengyuan , Zheng Xiaoming
Published: August 2002

Diethyl‐2,3‐dicyano‐2,3‐di‐(X‐substituted phenyl) succinates (X = p‐OCH3, p‐CH3, p‐Cl, H, p‐NO2) can initiate the free‐radical polymerization of styrene. The decomposition rate constant and activation energy were measured by means of a dilatometer, and the results showed that they were strongly dependent on the ratio of meso‐ and dl‐isomers in the polysubstituted dibenzyl compounds and the properties of the ring substituents. On the other hand, it was found that the polystyrenes, which were obtained by initiation with hydrogen, had a much larger average molecular weight than that with p‐OCH3 and p‐CH3. The experimental phenomena were correlated with the structure of the radical resulting from hydrogen. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2964–2971, 2001
Role of initial polymer concentration in the physical properties of zone‐drawn biodegradable poly(butylene adipate) film
Authors: Lyoo Won Seok , Kim Joon Ho , Yoon Won Sik , Ji Byung Chul , Lee Jinwon , Yang Su Bong , Yoo Yongtai , Nam Hyo‐Duk
Published: August 2002

The effects of initial polymer concentration and zone drawing on the physical properties and hydrolytic degradation of poly(butylenes adipate) (PBA) film were investigated to prepare PBA film with various biodegradabilities and physical properties for particular uses. It was identified from the results that the initial concentration of PBA solution in chloroform caused significant changes in draw ratio of the PBA film. The maximum draw ratio of 8.2, tensile strength of 0.59 GPa, and tensile modulus of 7.8 GPa were obtained at the initial concentration of 12 g/dL, measured as an optimum polymer concentration for film casting. The chain orientations and tensile properties of the PBA film cast at this concentration were superior to those of the PBA films cast at the other concentration, although they had the same draw ratio and similar crystallinity. The hydrolytic degradation rate of the film cast at 12 g/dL was lowest among the films having the same draw ratio, film dimension, and crystallinity, indicating that degradation behaviors were greatly affected by the initial polymer concentration and the molecular orientation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1–7, 2001
Effect of heavy‐ion irradiation on the gas permeability of poly(ethylene terephthalate) (PET) membranes
Authors: Takahashi Shuichi , Yoshida Masaru , Asano Masaharu , Tanaka Tomohiro , Nakagawa Tsutomu
Published: August 2002

A poly(ethylene terephthalate) (PET) membrane was used to study the effect of heavy‐ion irradiation on gas permeability and selectivity. In an ambient temperature range of 303–333 K, permeability coefficients for He, N2, O2, and CO2 were determined with the vacuum‐pressure and time‐lag methods. Gas‐permeability coefficients of the membranes, which were irradiated with some specific heavy ions, increased remarkably without a significant change in the polymer structure by ion irradiation. The permeation rates of these membranes were inversely proportional to the square root of the molecular weight of the gasses and showed Knudsen flow because of the formation of pores caused by heavy‐ion irradiation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 206–216, 2001
Morphology of a linear polymer‐modified epoxy‐amine formulation cured by microwave energy at different heating rates
Authors: Hedreul Claire , Galy Jocelyne , Dupuy Jérôme , Delmotte Michel , More Claude
Published: August 2002

Microwave energy was used to cure a bisphenol A diglycidyl ether‐based epoxy resin with an aromatic diamine curing agent (4,4′‐diaminodiphenylsulfone) in the presence of a rubber (epoxy‐terminated butadiene–acrylonitrile copolymer) or a thermoplastic (polyetherimide). Because microwaves allow high flexibility in the choice of the cure schedule, samples were cured at different heating rates between 3 and 110°C/min. The morphologies of the systems were studied as a function of the cure schedule. Scanning and transmission electron microscopy and differential scanning calorimetry were used to characterize the generated morphologies. The influence of the heating rate on the particle size distribution, the volume fraction of the dispersed phase, and the composition of both phases are discussed. The generated morphologies were found to be conditioned by the time–temperature profile, no matter what kind of heating was used. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1118–1128, 2001
Pervaporation of nonaqueous ethanol azeotropes through interpenetrating polymer network membranes prepared from poly(4‐vinylpyridine) and poly(vinyl alcohol)
Authors: Oikawa Eizo , Nozawa Kayo , Kaneko Takashi , Aoki Toshiki
Published: August 2002

Highly hydrophilic interpenetrating polymer network (IPN) membranes were prepared from a mixture system of poly(4‐vinylpyridine) (P4VP) and poly(vinyl alcohol) (PVA) by quaternizing crosslinking of P4VP with 1,4‐dibromobutane (DBB) and simultaneous crosslinking of PVA with hexamethylene diisocyanate (HMDI). The membrane performance in pervaporation (PV) for the azeotropic mixture of ethanol with a less polar organic liquid (chloroform, benzene, carbon tetrachloride, and cyclohexane) was investigated. The strength of these IPN membranes was higher than that of the cellulose acetate membrane and depended on the membrane composition. All the membranes were ethanol permselective for the azeotropic feeds and equimolar mixture feeds as well. Only the swelling degree Q of the membrane, among several physicochemical factors, showed a relationship with the separation performance for the four feeds; a lower value of Q generally corresponded to a higher separation factor and smaller permeability. The membrane composition, which exhibited an optimum membrane performance, was examined in detail for some membranes. Both the separation factor for sorption and that for diffusion far exceeded unity, but the latter was greater in most cases than was the former and dominated the overall separation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2729–2738, 2001
Thermal and mechanical behaviors of poly(vinyl alcohol)–lactose blends
Authors: Fan Xiao‐Dong , Hsieh You‐Lo , Krochta John M.
Published: August 2002

Thermal and mechanical behaviors of poly(vinyl alcohol) (PVA)–lactose blends were studied by differential scanning calorimetry, thermal gravimetric analysis, and stress–strain analysis. The increase in glass transition temperature of the PVA–lactose blends with lactose contents suggests the formation of hydrogen‐bonded PVA–lactose complex in the PVA matrix. The hydrogen bonding interactions can improve thermal and mechanical properties of the blends. Results of this study demonstrate that lactose, a byproduct of dairy industry, can be used directly and in substantial quantity (33%) as a modifier to enforce the physical properties of PVA. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 929–935, 2002
Ostracoda (Crustacea) from the Turkish Ramsar site of Lake Kuş (Manyas Gölü)
Authors: Altınsaçlı Selçuk , Griffiths Huw I.
Published: August 2002

1. Lake Kuş (Manyas Gölü), an important bird conservation area, was sampled in the summer, autumn, winter and spring of 1997, and the seasonal and spatial distributions of ostracods were investigated. Many of the taxa collected are useful indicator species for monitoring conditions within lake basins.

2. The findings suggest that the L. Kuş ecosystem is already substantially degraded. Pollution, coupled with extensive water abstraction for irrigation, have damaged the value of the lake, both commercially (as an inland waters fishery), and as an important site for wetland bird conservation.

3. This work shows that ostracod faunal analysis has value in the study of such sites, particularly where more formal physical, chemical and biological monitoring methods are inappropriate or unavailable. Copyright © 2001 John Wiley & Sons, Ltd.
Motor pudendal nerve characterization in the female rat
Authors: Kane Derek D. , Shott Susan , Hughes W. Frank , Kerns James M.
Published: August 2002

The aim of our study was to provide quantitative data on pudendal motor neuron cell bodies and axons in the female rat. To confirm earlier studies, fluorescent retrograde tracers were used to label the motor neurons for correlation with myelinated axon counts along the length of the motor pudendal nerve. The external urethral sphincter of female rats was injected with diamidino yellow and the external anal sphincter with fast blue. The L6 spinal cord revealed labeled motor neurons. Those in the dorsolateral column (60.8 ± 10.6) had nuclei labeled yellow from the external urethral sphincter and those in the dorsomedial column (31.7 ± 8.5) had cytoplasm labeled blue from the external anal sphincter. Double labeling was not present, suggesting that pudendal motor neurons in each column innervate separate sphincters. The motor pudendal nerve in the ischiorectal fossa was also characterized by light microscopy. The mean myelinated axon count (151.4 ± 17.0) was highly correlated (r = 0.995) in the proximal fascicles and the sum of distal fascicles. This indicated that myelinated axons do not branch at the point where the main motor pudendal nerve branches into separate fascicles. Axon counts between sides were not as well correlated (r = 0.883). The ratio of motor neurons to myelinated axons is 56%, suggesting that some myelinated axons either innervate other muscles or are sensory. This reproducible characterization of the normal pudendal nerve anatomy provides an excellent basis for experimental studies associated with pudendal nerve denervation as a model for neurogenic incontinence. Anat Rec 266:21–29, 2002. © 2002 Wiley‐Liss, Inc.
Reporter gene construct containing 1.4‐kB α1‐proteinase inhibitor promoter confers expression in the cornea of transgenic mice
Authors: Ueda Jun , Li Yuhong , Goh Meilan Stephanie , Maruyama Yasuhiro , Sugar Joel , Yue Beatrice Y.J.T.
Published: August 2002

A 1.4‐kb human α1‐proteinase inhibitor (α1‐PI) 5′‐flanking sequence fused to the E. coli LacZ gene was used to generate transgenic mice. The 1.4‐kb α1‐PI fragment was found to target LacZ expression preferentially in the epithelium and stroma of the mouse cornea, and moderately or weakly in white blood cells and a few other tissues, such as the skin and brain. This finding implies that the α1‐PI promoter may offer an option for targeting foreign genes in both the epithelial and stromal layers of the cornea in future transgenic experiments. Anat Rec 266:5–9, 2002. © 2002 Wiley‐Liss, Inc.
Determination of the orientation of collagen fibers in human bone
Authors: Osaki Shigeyoshi , Tohno Setsuko , Tohno Yoshiyuki , Ohuchi Kazuo , Takakura Yoshinori
Published: August 2002

A human calcaneus bone, consisting of hydroxyapatite and collagen fibers, was successively sliced into samples in a direction perpendicular to the long axis of the bone and parallel to the long axis of the human lower limb. The transmitted microwave intensities of 12 GHz, reflecting the dielectric property, were measured for the slice samples using Osaki's microwave method (Tappi J., 1987; 70:105–108). The complex dielectric constant of 12 GHz of the collagen fiber film was much greater than that of hydroxyapatite disc, which demonstrated that the dielectric anisotropy observed for the sliced bone was mainly affected by the collagen fibers. The angular dependence of the transmitted microwave intensity gives the orientation angle reflecting the direction of the collagen‐fiber orientation, and the degree of orientation reflecting the anisotropic property of collagen fibers. The orientation angle and the degree of orientation for the slice samples changed with changing position along the long axis of the calcaneus bone. The direction of orientation deviated to the lateral side at the heel part of the left calcaneus, and to the medial side at the middle part. The degree of orientation is relatively high at the heel part and low at the middle. Such results give a two‐dimensional distribution of collagen‐fiber orientation in the left calcaneus, and suggest that the direction and degree of orientation are closely related to the direction and magnitude of the stress applied to the bone, respectively. Anat Rec 266:103–107, 2002. © 2002 Wiley‐Liss, Inc.
Cell kinetic study of the endometrium by nonisotopic in situ hybridization for histone H3 messenger RNA and immunohistochemistry for Ki‐67 and for estrogen and progesterone receptors
Authors: Hayama Masayoshi , Ota Hiroyoshi , Toki Toshihiko , Ishii Keiko , Honda Takayuki , Momose Masanobu , Nakata Ritsuko
Published: August 2002

We investigated the cell kinetics of the endometrium in hysterectomy specimens taken for leiomyoma from 22 women with regular ovulatory menstrual cycles. Formalin‐fixed, paraffin‐embedded tissue sections were examined for proliferating activity using histone H3 messenger RNA in situ hybridization (H3 mRNA‐ISH) and immunostaining for the Ki‐67 antigen. The relationship of the proliferative activity of endometrial cells to the immunohistochemical expression of the estrogen receptor (ER) and the progesterone receptor (PR) was also examined. During the menstrual cycle, H3 mRNA expression was observed in both the epithelial cells and the stromal cells of the endometrium. In the functional layer, the labeling indices for H3 mRNA (H3 mRNA‐LIs) in the epithelial cells peaked in the late proliferative phase, decreased sharply in the early secretory phase, and remained unchanged thereafter. On the other hand, H3 mRNA‐LIs of stromal cells displayed two peaks: one in the midproliferative phase and the other in the late secretory phase, the former peak being the greater. In the basal layer, epithelial cells and stromal cells showed low H3 mRNA‐LIs and no significant variation throughout the menstrual cycle. The H3 mRNA‐LIs correlated well with the Ki‐67‐LIs and were lower than the corresponding Ki‐67‐LIs. The regression coefficient (H3 mRNA‐LIs against the Ki‐67‐LIs) was 0.33 for epithelial cells and 0.49 for stromal cells, suggesting that the cell cycle time was longer for epithelial cells than for stromal cells. The proliferative activity of endometrial cells showed close relationships with the expressions of ER and PR in the endometrium. When used in combination with other proliferative markers in paraffin‐embedded tissue sections, H3 mRNA‐ISH could open broader perspectives on the cell kinetics of the endometrium. Anat Rec 266:234–240, 2002. © 2002 Wiley‐Liss, Inc.
An ultrastructural study of germ cells during ovarian differentiation in Torpedo marmorata
Authors: Prisco Marina , Ricchiari Loredana , Andreuccetti Piero
Published: August 2002

An ultrastructural investigation, performed on embryos, neonates, subadult and adult females, demonstrated that in Torpedo marmorata oogenesis occurs very early in life and continues, in its proliferative phase, also after birth. Clusters of early meiotic cells were already evident in the ovarian cortex of 6‐cm‐long embryos, as well as in the ovary of newborns and three‐month‐old young. Conversely, in the ovaries of subadult and adult females, all the germ cells present were organized into follicles, and no clusters of oogonia and early meiotic cells were generally found in the cortex, except for one adult female where clusters of germ cells not organized in follicles were found in the cortex. These data demonstrated that, in Torpedo marmorata, oogenesis is immediate, and, as oogonia persist after birth, more similar to that of mouse, monkey, rabbit, and ferret (Mauleon Arch Anat Microsc, 1967; 56:125–150; Byskov and Hoyer 1994) than to that of human, rat, pig, and guinea pig (Byskov and Hoyer 1994). Such a pattern is in agreement with the reproductive strategy of Torpedo, a scantly prolific species with low uterine fecundity. The presence of meiotic cells that are not organized in follicles in one adult female might be consistent with the large individual variability characterizing cartilaginous fishes. The possibility that such a character is typical of mature females should be rejected as oogonia and early meiotic cells were not found inside the totally sectioned gonads of subadult and adult females. Anat Rec 263:237–245, 2001. © 2001 Wiley‐Liss, Inc.
Effect of geminivirus infection and Bemisia infestation on accumulation of pathogenesis‐related proteins in tomato
Authors: McKenzie C.L. , Shatters Robert G. , Doostdar H. , Lee S.D. , Inbar Moshe , Mayer Richard T.
Published: August 2002

The whitefly, Bemisia tabaci biotype B, has been shown to cause pathogenesis‐related (PR) proteins to accumulate in plants as a result of direct feeding, but their specific role in plant defensive systems is unclear. Our objective was to compare accumulation of tomato PR proteins (β‐1,3‐glucanase, chitinase, peroxidase, P2 and P4) in response to whitefly, with or without tomato mottle virus (ToMoV) infection. Tomato PR protein response was measured over time in plants divided into three treatments: uninfected controls (with or without whiteflies) and plants infested with viruliferous (ToMoV) whiteflies. Five‐ to six‐leaf plants were infested with ∼5 adult whitefly per leaf. Plants were sampled prior to whitefly infestation and at 14, 28, 42, and 56 days. By 56 days, plants infested with viruliferous whiteflies had significantly more eggs (2.5‐fold) and nymphs (4.5‐fold) than plants with nonviruliferous whiteflies. A significant increase in the enzymatic activity of all measured PR proteins, as compared to control plants, was only seen in viruliferous whitefly‐infested plants. No significant difference was observed in enzyme activities between the uninfected control plants either with or without whiteflies. The greatest differences for all PR proteins assayed were observed 42 days after treatment initiation. Protein blot analyses showed that the differences in PR protein activities among the treatments were due to changes in specific enzyme levels within the plant and were associated with concomitant increases in levels of P2 and P4 PR proteins. Under our experimental conditions, it is clear that PR protein response is much more intense when it is attacked by whiteflies carrying ToMoV than by whitefly alone. Arch. Insect Biochem. Physiol. 49:203–214, 2002. Published 2002 Wiley‐Liss, Inc.
“Ambiguity” and scientometric measurement: A dissenting view
Authors: Burrell Quentin L.
Published: August 2002

Abe Bookstein has long been a persuasive advocate of the central role of the classical Lotka‐Bradford‐Zipf “laws” in bibliometrics and, subsequently, scientometrics and informetrics. In a series of often‐quoted papers (Bookstein, 1977, 1990a, 1990b, 1997), he has sought to demonstrate that “Lotka‐type” laws have a unique resilience to various forms of reporting, which leads inevitably and naturally to their observance in empirical informetric data collected under a wide variety of circumstances. A general statement of his position was featured in the recent JASIST Special Topic Issue on Information Science at the Millennium (Bookstein, 2001). We shall argue that there are grounds to dispute some of the logic, the mathematics, and the reality of the development. The contention is on the one hand that Bookstein's development lacks a rigorous mathematical basis, and on the other, that, in general, informetric processes are adequately described within a standard probabilistic framework with stochastic modelling offering the more productive approach.
Absence of clinically relevant drug interactions following simultaneous administration of didanosine‐encapsulated, enteric‐coated bead formulation with either itraconazole or fluconazole
Authors: Damle B. , Hess H. , Kaul S. , Knupp C.
Published: August 2002

This open‐label, two‐way crossover study was undertaken to determine whether the enteric formulation of didanosine influences the pharmacokinetics of itraconazole or fluconazole, two agents frequently used to treat fungal infections that occur with HIV infection, and whose bioavailability may be influenced by changes in gastric pH. Healthy subjects were randomized to Treatment A (200‐mg itraconazole or 200‐mg fluconazole) or Treatment B (same dose of itraconazole or fluconazole with 400 mg of didanosine as an encapsulated, enteric‐coated bead formulation). In the itraconazole study, a lack of interaction was concluded if the 90% confidence interval (CI) of the ratio of the geometric means of log‐transformed Cmax and AUC0–T values of itraconazole and hydroxyitraconazole, the active metabolite of itraconazole, were contained entirely between 0.75 and 1.33. In the fluconazole study, the equivalence interval for Cmax and AUC0–T was 0.80–1.25. The data showed that for itraconazole the point estimate and 90% CI of the ratios of Cmax and AUC0–T values were 0.98 (0.79, 1.20) and 0.88 (0.71, 1.09), respectively; for hydroxyitraconazole the respective values were 0.91 (0.76, 1.08) and 0.85 (0.68, 1.06). In the fluconazole study, the point estimate and 90% CI of the ratios of Cmax and AUC0–T values were 0.98 (0.93, 1.03) and 1.01 (0.99, 1.03), respectively. The Tmax for itraconazole, hydroxyitraconazole, and fluconazole were similar between treatments. Both studies indicated a lack of clinically significant interactions of the didanosine formulation with itraconazole or fluconazole. These results showed that the encapsulated, enteric‐coated bead formulation of didanosine can be concomitantly administered with drugs, such as the azole antifungal agents, whose bioavailability may be influenced by interaction with antacids. Copyright © 2002 John Wiley & Sons, Ltd.
Screening of chemiluminescence constituents of cereals and DPPH radical scavenging activity of γ‐oryzanol
Authors: Akiyama Yoshinobu , Hori Kazuyuki , Hata Keishi , Kawane Masaaki , Kawamura Yukio , Yoshiki Yumiko , Okubo Kazuyoshi
Published: August 2002

The chemiluminescence (CL) constituents of cereals were detected by CL using the H2O2–acetaldehyde system. The cereals tested, such as rice, millet and sorghum, exhibited various levels of CL activity. The γ‐oryzanol fraction was extracted from brown rice and separated into four constituents by HPLC. The four constituents were identified as cycloartenyl ferulate, 24‐methylenecycroartanyl ferulate, campesteryl ferulate and β‐sitosteryl ferulate. Free radical scavenging activities with 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) and CL intensities of four constituents (γ‐oryzanol components) were measured and compared with that of gallic acid, which is a typical free radical scavenger. Four constituents scavenged DPPH radicals and scavenging activities were proportional to CL intensities. Concentrations of four CL constituents required to quench 50% (IC50) of the free radicals ranged from 0.9 to 1.1 mmol/L. We demonstrated that measurement of CL intensities was a rapid and convenient method for screening DPPH radical scavenging activities of rice. Copyright © 2001 John Wiley & Sons, Ltd.
Density functional theory and surface enhanced Raman spectroscopy characterization of novel platinum drugs
Authors: Giese Bernd , Deacon Glen B. , Kuduk‐Jaworska Janina , McNaughton Don
Published: August 2002

There is considerable interest in the development of novel platinum‐based anticancer drugs that overcome the disadvantages associated with the widely used drug cisplatin, which are its inactivity against some types of tumors and its toxic side effects. In this study we show the suitability of normal Raman spectroscopy (NRS) and surface enhanced Raman spectroscopy (SERS), assisted by density functional theoretical (DFT) calculations, for the characterization of Pt complexes. The Pt complexes studied include the established drugs cisplatin and carboplatin, as well as five novel Pt complexes with anticancer activity. DFT calculations at the B3LYP/LanL2DZ level are a good prediction of the experimental NRS spectra of small and medium sized Pt complexes. The use of SERS allows the investigation of Pt complexes at physiological concentrations, and the binding strengths of the different ligands can be determined. The formation of positively charged hydrolysis products may be necessary for SERS activity. The exiting group in the hydrolysis reaction can be identified. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 67: 294–297, 2002
Bioaffinity purification of NADP+‐dependent dehydrogenases: Studies with alcohol dehydrogenase from Thermoanaerobacter brockii
Authors: McMahon Mary , Mulcahy Patricia
Published: August 2002

This study describes the development and application of a bioaffinity chromatographic system for the one‐step purification of an NADP+‐dependent secondary alcohol dehydrogenase from the obligate anaerobe, Thermoanaerobacter brockii (TBADH, EC 1.1.1.2). The general approach is based upon improving the selectivity of immobilized cofactor derivatives (general ligand approach to bioaffinity chromatography) through using soluble enzyme‐specific substrate analogues in irrigants to promote biospecific adsorption (the kinetic locking‐on tactic). Specifically, the following is described: Evaluation of 8′‐azo‐linked, C8‐linked, N1‐linked, and N6‐linked immobilized NADP+ derivatives for use with the kinetic locking‐on strategy for bioaffinity purification of TBADH; evaluation of 2′, 5′‐ADP as a stripping ligand for TBADH bioaffinity purifications using an 8′‐azo‐linked immobilized NADP+ derivative in the locking‐on mode; and application of the developed bioaffinity chromatographic system to the purification of TBADH from a crude cellular extract. Surprizingly, of the four immobilized NADP+ derivatives investigated, only the 8′‐azo‐linked immobilized NADP+ derivative proved effective for TBADH affinity purification when used in conjunction with pyrazole (a competitive inhibitor of TBADH activity) as the locking‐on ligand. This is in contrast to other NADP+‐dependent dehydrogenases where the immobilized N6‐linked cofactor proved to be suitable. While the one‐step purification of TBADH to electrophoretic homogeneity is described in the present study (92% yield), results from the model chromatographic studies point to improvements that could be made to the immobilized cofactor derivative to improve its suitability for TBADH bioaffinity purification and to facilitate future large scale protein purification operations. © 2002 John Wiley and Sons, Inc. Biotechnol Bioeng 77: 517–527, 2002; DOI 10.1002/bit.10079
Development of an ultrahigh‐temperature process for the enzymatic hydrolysis of lactose. IV. Immobilization of two thermostable β‐glycosidases and optimization of a packed‐bed reactor for lactose conversion
Authors: Petzelbauer Inge , Kuhn Bernhard , Splechtna Barbara , Kulbe Klaus D. , Nidetzky Bernd
Published: August 2002

Recombinant hyperthermostable β‐glycosidases from the archaea Sulfolobus solfataricus (SsβGly) and Pyrococcus furiosus (CelB) were covalently attached onto the insoluble carriers chitosan, controlled pore glass (CPG), and Eupergit C. For each enzyme/carrier pair, the protein‐binding capacity, the immobilization yield, the pH profiles for activity and stability, the activity/temperature profile, and the kinetic constants for lactose hydrolysis at 70°C were determined. Eupergit C was best among the carriers in regard to retention of native‐like activity and stability of SsβGly and CelB over the pH range 3.0–7.5. Its protein binding capacity of ∼0.003 (on a mass basis) was one‐third times that of CPG, while immobilization yields were typically 80% in each case. Activation energies for lactose conversion by the immobilized enzymes at pH 5.5 were in the range 50–60 kJ/mol. This is compared to values of ∼75 kJ/mol for the free enzymes. Immobilization expands the useful pH range for CelB and SsβGly by approximately 1.5 pH units toward pH 3.5 and pH 4.5, respectively. A packed‐bed enzyme reactor was developed for the continuous conversion of lactose in different media, including whey and milk, and operated over extended reaction times of up to 14 days. The productivities of the Eupergit C‐immobilized enzyme reactor were determined at dilution rates between 1 and 12 h−1, and using 45 and 170 g/L initial lactose. Results of kinetic modeling for the same reactor, assuming plug flow and steady state, suggest the presence of mass‐transfer limitation of the reaction rate under the conditions used. Formation of galacto‐oligosaccharides in the continuous packed‐bed reactor and in the batch reactor using free enzyme was closely similar in regard to yield and individual saccharide components produced. © 2002 John Wiley & Sons, Inc. Biotechnol Bioeng 77: 619–631, 2002; DOI 10.1002/bit.10110
Characterization of hybridoma cell responses to elevated pCO2 and osmolality: Intracellular pH, cell size, apoptosis, and metabolism
Authors: deZengotita Vivian M. , Schmelzer Albert E. , Miller William M.
Published: August 2002

CO2 partial pressure (pCO2) in industrial cell culture reactors may reach 150–200 mm Hg, which can significantly inhibit cell growth and recombinant protein production. The inhibitory effects of elevated pCO2 at constant pH are due to a combination of the increases in pCO2 and [HCO], per se, and the associated increase in osmolality. To decouple the effects of pCO2 and osmolality, low‐salt basal media have been used to compensate for this associated increase in osmolality. Under control conditions (40 mm Hg–320 mOsm/kg), hybridoma cell growth and metabolism was similar in DMEM:F12 with 2% fetal bovine serum and serum‐free HB GRO. In both media, pCO2 and osmolality made dose‐dependent contributions to the inhibition of hybridoma cell growth and synergized to more extensively inhibit growth when combined. Elevated osmolality was associated with increased apoptosis. In contrast, elevated pCO2 did not increase apoptotic cell death. Specific antibody production also increased with osmolality although not with pCO2. In an effort to understand the mechanisms through which elevated pCO2 and osmolality affect hybridoma cells, glucose metabolism, glutamine metabolism, intracellular pH (pHi), and cell size were monitored in batch cultures. Elevated pCO2 (with or without osmolality compensation) inhibited glycolysis in a dose‐dependent fashion in both media. Osmolality had little effect on glycolysis. On the other hand, elevated pCO2 alone had no effect on glutamine metabolism, whereas elevated osmolality increased glutamine uptake. Hybridoma mean pHi was ∼0.2 pH units lower than control at 140 mm Hg pCO2 (with or without osmolality compensation) but further increases in pCO2 did not further decrease pHi. Osmolality had little effect on pHi. Cell size was smaller than control at elevated pCO2 at 320 mOsm/kg, and greater than control in hyperosmotic conditions at 40 mm Hg. © 2002 John Wiley & Sons, Inc. Biotechnol Bioeng 77: 369–380, 2002; DOI 10.1002/bit.10176
An automatic system for the assessment of complex medium additives under cultivation conditions
Authors: Iding K. , Büntemeyer H. , Gudermann F. , Deutschmann S. M. , Kionka C. , Lehmann J.
Published: August 2002

Complex medium additives such as yeast extract or peptone are often used in industrial cell culture processes to prolong cell growth and/or to improve product formation. The quality of those supplements is dependent on the preparation method and can differ from lot to lot. To guarantee consistent production these different lots have to be tested prior to use in fermentation processes. Because a detailed qualitative and quantitative analysis of all components of such a complex mixture is a very difficult task, another assessment method has to be chosen. The best way to evaluate the effect of such supplements is to monitor cell activity during real cultivation conditions with and without the added supplement lot. A bioreactor‐based test system has been developed to determine the oxygen requirement of the cells as a response to the addition of a supplement to be tested under standardized conditions.

Investigations were performed with a mouse‐mouse hybridoma cell line and yeast extracts as an example for complex medium additives. The results showed differences in the impact between different extract lots and between different concentrations of an extract. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 73: 442–448, 2001.