bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antimony biomethylation by the wood rotting fungus Phaeolus schweinitzii
Authors: Andrewes Paul , Cullen William R. , Polishchuk Elena , Reimer Ken J. 
Published: August 2002

AbstractThe wood rotting fungus, Phaeolus schweinitzii, efficiently transforms the antimony(III) compounds potassium antimony tartrate and antimony trioxide to nonvolatile dimethylantimony and trimethylantimony species. The organoantimony species were detected in potato dextrose broth media samples by using hydride generation–gas chromatography–atomic absorption spectroscopy (HG–GC–AAS). The average concentrations of trimethylantimony species after 40 days incubation with potassium antimony tartrate were approximately 35 μg, 155 μg and 520 μg Sb/l, for substrate concentrations of 10 mg, 100 mg and 1000 mg Sb/l respectively. Thus, the maximum yield of trimethylantimony species was approximately 0.4%. When antimony trioxide (saturated solution, 4 mg Sb/l) was used as a substrate, the average concentration of trimethylantimony species was 150 μg Sb/l after 40 days. The HG–GC–AAS response for the dimethylantimony species was less than that for the trimethylantimony species; however, quantification was not possible because of the lack of an appropriate standard. In comparison, cultures of P. schweinitzii incubated with 1 mg As/l as sodium arsenite contained approximately 200 μg As/l as trimethylarsenic species, i.e. 20% yield. Biomethylation of antimony(V) was inefficient: cultures contained only 3 μg Sb/l as trimethylantimony species after incubation with 100 mg Sb/l as potassium hexahydroxyantimonate. No organoantimony species were detected in control cultures that contained only medium and inorganic antimony compounds. The identities of the organoantimony species were confirmed by using GC–Mass Spectrometry.
Magnetic nanocomposites from nitrogen base polymers
Authors: Millan A. , Palacio F. 
Published: August 2002

AbstractPolymers containing nitrogen basic groups can be used in the preparation of metal oxide–polymer nanocomposites thanks to the capacity of the N atoms to coordinate iron ions. In this work, nanocomposites consisting of iron oxide and poly(4‐vinylpyridine) polymer have been prepared. The materials are produced by suspending beads of the polymer in a metal salt solution. Superparamagnetic nanoparticles of metal oxides or hydroxides are grown within the polymer–metal complex gel by drying in an oven. The reaction of the polymer with the metal solution takes place by a surface reaction mechanism. Contrary to cross‐linked polymers, this mechanism of reaction allows the production of materials with different nanoparticle sizes. Copyright © 2001 John Wiley & Sons, Ltd.
Optothermal properties of fiber morphology on nylon 66 fibers due to annealing and drawing processes
Authors: Fouda I. M. 
Published: August 2002

AbstractThe changes produced by the effects of annealed and drawn fibers on the microstructure and macrostructure of nylon 66 fibers are considered. The optical properties and strain produced in nylon 66 fibers under different conditions are measured interferometrically at room temperature. Structural parameters are calculated such as the average work per chain, the work per unit volume, the reduction in entropy due to elongation, and the work stored in the body as strain energy. The evaluation of the density aided the calculation of the crystallinity, the mean square density fluctuation, the isotropic refractive index, the harmonic mean polarizability of the dielectric, and the harmonic mean specific refractivity. In addition, the resulting data are utilized to calculate the optical stress coefficient and the optical configuration and to apply the Mooney–Rivlin equation to determine its constants. Also, the number of crystals per unit volume and the average orientation angle for uniaxial stretching are calculated by the extension ratio. The relations between the optical, mechanical, and thermal changes with different parameters are given for the studied fibers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 916–928, 2002; DOI 10.1002/app.10107
Graft copolymerization studies. III. Methyl methacrylate onto polypropylene and polyethylene terephthalate
Authors: Dokolas Peter , Qiao Greg Guanghua , Solomon David H. 
Published: August 2002

AbstractThe tert‐butoxy radical‐facilitated grafting of methyl methacrylate (MMA) onto commercial polypropylene (PP) pellets and fiber was investigated in heterogeneous conditions similar to practical systems. Free‐radical grafting of several other monomers onto PP fiber was also investigated. Also, preliminary data from the grafting of MMA onto poly(ethylene terephthalate) pellets is presented. The PP‐graft‐PMMA residues were detected by solid‐state 13C‐NMR and photoacoustic IR spectroscopy. There was a good correlation between the degree of grafting (DG) determined from these spectroscopic techniques and the results from gravimetric methods. A maximum grafting efficiency of over 50% was found, whereas DG (20%) remained constant at various PP pellet, initiator, and monomer concentrations. However, at relatively low PP fiber concentrations, the DG was 27%; the increase was most likely due to the greater surface area of the fiber. There was also a reduction in DG (14%) at relatively low initiator concentrations. The reaction conditions were altered to favor grafting by the addition of more polymer substrate. When the ratio of tert‐butoxy radicals to PP was decreased, more of the substrate remained unmodified, and empirical calculations showed the formation of grafts with up to 40 monomer units. At high initiator concentrations, calculations showed that the graft residues were 1–2 units long. Therefore, variation of the polymer, initiator, and monomer concentrations was shown to have a significant effect on grafting. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 898–915, 2002
Characterization of UV‐curable reactive diluent containing quaternary ammonium salts for antistatic coating
Authors: Hong J. W. , Kim H. K. , Yu J. A. , Kim Y. B. 
Published: August 2002

AbstractReactive diluent with quaternary ammonium salts (RDQ) for UV‐curable antistatic coating was synthesized by reacting glycidyl methacrylate (GMA) and piperazin with dropping the methansulfonic acid. In order to compare the curing behavior of RDQ with commercial monomers, the photopolymerization of RDQ, 1,6‐hexandiol diacrylate (HDDA) and 1,6‐hexandiol dimethacrylate (HDDMA) were studied by using real‐time IR spectroscopy. Surface properties such as surface resistance, pencil hardness, and solvent resistance of the cured films containing RDQ were investigated. When used as a reactive diluent in the UV‐curable coating formulation, the RDQ imparted excellent antistatic properties to the final material. The results of an Fourier transform infrared/attenuated total reflectance (FTIR/ATR) depth profile analysis show that RDQ molecules are more concentrated near the surface within a micrometer‐thick layer, indicating that existence of the ionic components in the surface layer is responsible for antistatic property. Film cured from the formulation containing 12 wt % of RDQ showed the best mechanical properties with reasonable surface properties. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 132–137, 2002; DOI 10.1002/app.10273
Carbon‐13 solution and solid‐state NMR investigation of alpha‐methylstyrene‐co‐acrylonitrile
Authors: Nogueira Regina F. , Tavares Maria Inês B. 
Published: August 2002

AbstractNuclear magnetic resonance spectroscopy (NMR) gave information on the behavior of alpha‐methylstyrene‐co‐acrylonitrile. The comonomer sequence distribution in the copolymer and the depolymerization process were detected by solution analysis. The solid‐state NMR investigation showed that 13C routine spectra such as MAS and CPMAS allowed one to obtain information on the molecular domains of chains and also permitted evaluation of the domains' mobility. In this case, the mobile domain was formed by alpha‐methylstyrene (AMS). The variable contact time and the proton spin‐lattice relaxation time in the rotating‐frame parameter were determinant factors to evaluate the dynamic molecular behavior and the homogeneity of the comonomer distribution along the copolymer chains. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 138–143, 2002; DOI 10.1002/app.10275
Preparation and structural characterization of water‐soluble O‐hydroxypropyl chitin derivatives
Authors: Park In Kyu , Park Young Hwan 
Published: August 2002

AbstractWater‐soluble hydroxypropyl chitin (HPC) derivatives were prepared by the reaction of chitin with propylene oxide in homogeneous conditions using a dimethylacetamide/5% lithium chloride solvent system. The reaction conditions for a proper substitution of the hydroxypropyl group were an 80°C reaction temperature, 24‐h reaction time, and 48‐h aging time. 1H‐NMR and 13C‐cross‐polarization/magic angle spinning NMR spectroscopy were used for determining the substitution value and reaction site of substitution. It was found that the substitution reaction occurred mainly at the C6OH group in the chitin molecules and water‐soluble chitin derivatives could be obtained at a substitution value higher than 0.35, which is known as a critical substitution value. X‐ray diffraction analysis and FTIR spectroscopy showed that the structural characteristics of HPC derivatives were dependent on the substitution value. As the substitution value of the HPC derivative increased the α‐chitin crystal structure changed to the water‐soluble β‐chitin form in higher substitution values. Differences in the interchenic hydrogen bonding, interplanar spacing of the crystal lattice plane, and crystallinity can explain the structural changes upon substitution. The thermal decomposition temperature was also related to the characteristics of the crystalline structure, depending on a critical substitution value. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2624–2632, 2001
Abatement of heavy metals and softening of hard water by the CoAlPO4‐5/polysulfone membrane
Authors: Lin Shiow‐Shyung , Chen Shih‐Hsiung , Chang Chia‐Yan , Chang Dong‐Jang , Chen Chia‐Chrn 
Published: August 2002

AbstractTo improve the membrane, if CoAlPO4‐5 was appropriately added, it could increase the rejection rate of metal ions compared with the PSf membrane. Besides, penetration rate would also increase, and the pressure applied could be lowered when the improved membrane was used. The optimum amount of CoAlPO4‐5 added for Co : Al : P = 0.1 : 0.92 : 1.0 is about 5 wt %, while for the Co : Al : P = 0.08 : 0.93 : 1.0, this optimum value would shift toward a higher wt % because the latter has less active sites per unit weight of CoAlPO4‐5. The hydrated radius of metal ion had great influence on the rejection rate. The larger the radius, for example, that of the +3 valence cations, the higher the rejection rate would exhibit, and the rate for Cd2+was much lower because its radius was the smallest one. Moreover, although incompatibility existed in the improved membrane and the variation of applied pressure was limited, durability of this membrane under the operating conditions was good. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2768–2773, 2001
Swelling–deswelling behavior of poly(acrylamide‐co‐maleic acid) hydrogels
Authors: Bajpai S. K. 
Published: August 2002

AbstractIn this study the poly(acrylamide‐co‐maleic acid) hydrogels containing small amounts of maleic acid have been synthesized, and the effect of pH, ionic strength, and nature of counterions on the equilibrium water uptake has been investigated. The incorporation of small amount of maleic acid results in the transition of swelling mechanism from Fickian to non‐Fickian. The equilibrium mass swelling has been found to increase with pH of the swelling medium while increase in ionic strength causes a decrease in the swelling. The amount of maleic acid present in the hydrogel affects the swelling behavior in rather an unusual way. With lower acid contents, the equilibrium mass swelling increases while higher concentrations of maleic acid cause a decrease in the degree of swelling. The hydrogels have been found to undergo a number of swelling–deswelling cycles when pH of the swelling medium changes from 8.0 to 2.0. Hydrogels require more time to deswell compared to the time required for swelling, which has been explained on the basis of the fact that gels follow different mechanisms for the two processes. Various swelling parameters such as equilibrium mass swelling, diffusion coefficient, intrinsic diffusion coefficient, swelling exponent, etc., have been evaluated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2782–2789, 2001
Electro‐induced polymerization of acrylamide initiated by the potassium permanganate–titriplex VI redox system
Authors: Saraç A. Sezai̇ , Soydan A. Bahattin , Bülbül Hayal 
Published: August 2002

AbstractThe polymerization of acrylamide (AAm) was carried out with a potassium permanganate–Titriplex VI redox initiator system with and without electrolysis. Because of the high metal‐ion concentration in general, low‐molecular‐weight polymers were obtained (weight‐average molecular weight = 2600–4000). The effect of potassium permanganate and AAm concentrations and temperature on the polymerization yield was studied and compared with results obtained under the same experimental conditions used for electrolysis. The results of Fourier transform infrared spectroscopy, atomic absorption spectrometry, and scanning electron microscopy (SEM) results are given. SEM micrographs of the polymer obtained by electrochemical methods exhibited smoother surfaces than those obtained by nonelectrolytic methods. In the absence of potassium permanganate, there was no polymerization under experimental conditions. A possible reaction mechanism is suggested. The electro‐induced system resulted in about a 50% increase in the yield. Manganese content in the electro‐induced and chemical polymerization systems were 2.7 and 8.2%, respectively, supporting the yield increase in the electro‐induced system. A graphite electrode was used and resulted in a high yield and a fibrous polymeric structure. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1526–1534, 2001
Melting behavior and crystallization kinetics of poly(butylene terephthalate‐co‐diethylene terephthalate) and poly(butylene terephthalate‐co‐triethylene terephthalate) copolyesters
Authors: Finelli Lara , Lotti Nadia , Righetti Maria Cristina , Munari Andrea 
Published: August 2002

AbstractThe melting behavior of poly(butylene terephthalate‐co‐diethylene terephthalate) and poly(butylene terephthalate‐co‐triethylene terephthalate) copolymers was investigated by differential scanning calorimetry after isothermal crystallization from the melt. Multiple endotherms were found for all the samples, and attributed to the melting and recrystallization processes. By applying the Hoffman‐Weeks' method, the equilibrium melting temperatures of the copolymers under investigation were obtained. Two distinct peaks in the crystallization exothermic curve were observed for all the samples. Both of them appeared at higher times than that of PBT, indicating that the introduction of a comonomer decreased the crystallization rate. The observed dependence of this latter on composition was explained on the basis of the content of ether–oxygen atoms in diethylene and triethylene terephthalate units, and of the different sizes of these units. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3545–3551, 2001
Cationized sawdust as ion exchanger for anionic residual dyes
Authors: Baouab Mohamed Hassen V , Gauthier Robert , Gauthier Hélène , El Baker Rammah Mohamed 
Published: August 2002

AbstractUsing the same procedure as recently described for cotton fiber, the preparation of cationized wood sawdust was performed by treating alkali sawdust with epoxy propyl trimethyl ammonium chloride (EPTMAC) in a nonaqueous medium (dimethylformamide, DMF). The fixation of ammonium groups onto sawdust was monitored by weight uptake, nitrogen content determination, and infrared spectroscopy. EPTMAC‐sawdust with a 0.5 wt % nitrogen content is then used as adsorbent for acid dyes (Acid Blue 25, Acid Yellow 99, Reactive Yellow 23, and Acid Blue 74). The adsorption capacity, determined by spectrometric measurement of the residual dye in the treated solution, decreases with increasing temperature. The modeling of the adsorption isotherms using Langmuir, Freundlich, and General relations allows the determination of isotherm constants. Globally, EPTMAC‐sawdust has a behavior similar to EPTMAC‐cotton, and its use for depollution of waste waters from dyeing industries presents advantages over cotton, such as a larger availability and a lower price. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 31–37, 2001
Graft copolymerization of methyl methacrylate onto sago starch using ceric ammonium nitrate and potassium persulfate as redox initiator systems
Authors: Fakhru'L‐Razi A. , Qudsieh Isam Y. M. , Yunus Wan Md Zin Wan , Ahmad Mansor B. , Rahman Mohamad Zaki Ab. 
Published: August 2002

AbstractThe graft copolymerization of methyl methacrylate (MMA) onto sago starch was carried out in aqueous media by different initiators of ceric ammonium nitrate (CAN) and potassium persulfate (PPS) and under a nitrogen gas atmosphere. Using CAN as an initiator, the maximum percentage of grafting (%G) was ascertained to be 246% at the following optimum conditions: a 70°C reaction temperature, a 2‐h reaction period, 2.0 mmol of CAN, 0.4 mmol of nitric acid, and 141 mmol of MMA. The maximum %G achieved with PPS as the initiator was 90%. The optimum conditions were a 50°C reaction temperature, a 1.5‐h reaction period, 47 mmol of monomer, and 1.82 mmol of PPS. The grafting of MMA onto sago starch was confirmed by the IR spectra of pure sago starch, MMA, and MMA grafted sago starch. This material may have application as a biodegradable plastic. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1375–1381, 2001
Microvasculature of the buffalo epididymis
Authors: Scala Gaetano , De Girolamo Paolo , Corona Mario , Pelagalli Gaetano Vincenzo 
Published: August 2002

AbstractThe microvasculature of the water buffalo (Bubalus bubalis) epididymis was investigated using light (LM), scanning electron (SEM), and transmission electron (TEM) microscopy techniques. SEM analysis of the buffalo epididymis showed fenestrations that occupied ovoid inside the endothelium of the postcapillary venules located in thecaput,corpus,andcauda. They varied in shape and dimension, but more importantly, they connected the venules of the blood vascular system to the capillaries of the peripheral lymphatic vascular system. Morphofunctional analysis of these connections suggests that the microvasculature of the buffalo epididymis plays a role in facilitating the circulation of biologically active substances, and the absorption and secretion processes necessary for the survival and maturation of spermatozoa. The lymphatic capillaries at the connection points formed a network of variously sized polygonal links. These capillaries then converged to form the precollector lymphatic vessels, which in turn converged with the larger vessels originating from the testis. It was further noted that in the capillary endothelium there were no fenestrations, and in the large veins there were manydiverticula. Thesediverticulaappear to play a role in the regulation of the seasonal variations of the blood reflux. In general, the microvascular architecture of the buffalo epididymis, particularly its connection to the lymphatic vascular system, appears to play an important role in the absorption and secretion processes of the epididymal epithelium. Anat Rec 266:58–68, 2002. © 2002 Wiley‐Liss, Inc.
Quantitation of the changes in vascularity during arthritis in the knee joint of a mouse with a digital image analysis system
Authors: Buma Pieter , Groenenberg Martin , Rijken Paul F.J.W. , Van Den Berg Wim B. , Joosten Leo , Peters Hans 
Published: August 2002

AbstractMany joint and bone diseases are caused by, or associated with vascular changes. Particularly in rheumatoid arthritis, vascular sprouting of synovial vessels plays a major role in the generation of joint pathology. To assess the effects of pharmaceuticals that are designed to inhibit neovascularization, we developed a quantitative procedure to measure vascular changes in cross‐sections of the mouse knee joint during arthritic inflammation. Arthritis was induced in the knee joint of C57Black6 mice by a single subpatellar injection of methylated BSA after previous immunization. Total vascularity was visualized with a specific monoclonal rat anti‐mouse antibody (9F1). Functional vessels were detected with the fluorescent perfusion marker Hoechst 33342. The localization of Hoechst and the vascular marker 9F1 were analyzed in separate images with an automated digital image processing system. By combining the two images, total vascularity and the perfusion status of the vessels during arthritis could be established. The digital image system measures synovial area (SA), number of all blood vessels (NBV) and the number of perfused blood vessels (NpBV). From these parameters the percentage of perfused vessels (perfusion fraction; PF), the vessel density (VD = NBV/SA) and the density of perfused vessels (VDp = NpBV/SA) can be calculated. The measurements showed that the area of synovial tissue had increased during arthritis. Moreover, both the number of blood vessels (NBV) and the number of perfused vessels (NpBV) in the synovial area had increased significantly on Days 4 and 7 after arthritis induction. This procedure enabled quantitation of total vascularity and of functional blood vessels in cross‐sections of synovial tissue. It is expected to be a powerful tool, not only to analyze the effects of anti‐angiogenic therapies in animal models of arthritis, but could also be applicable to study vascular and perfusion changes in vascular related diseases of the skeleton. Anat Rec 262:420–428, 2001. © 2001 Wiley‐Liss, Inc.
Posterior maxillary (PM) plane and anterior cranial architecture in primates
Authors: McCarthy Robert C. , Lieberman Daniel E. 
Published: August 2002

AbstractThis study tests several hypotheses of integration between the cranial base and face in primates. After reviewing the definition and anatomical basis for the posterior maxillary (PM) plane, which demarcates the back of the midface at its junction with the sphenoid, we demonstrate how the PM plane can be identified accurately on radiographs, and confirm that it maintains a 90° angle relative to the Neutral Horizontal Axis of the orbits in all primates. In addition, we use the PM plane to test Dabelow's (1929) hypothesis that the orbits and anterior cranial base are more highly integrated in anthropoids than in strepsirrhines, and we test the hypothesis that the midline anterior cranial base (planum sphenoideum) and anterior cranial floor (planum sphenoideum plus cribriform plate) in primates are highly correlated with each other relative to the PM plane. The mean angle between the anterior cranial base and the PM plane does not differ significantly from 90° in anthropoids, but differs significantly in strepsirrhines. The anterior cranial base and anterior cranial floor, however, correlate well with each other relative to the PM plane in both suborders of primates, independent of orbital orientation and configuration. The PM plane, anterior cranial base, and anterior cranial floor, therefore, form an integrated structural complex, a “facial block,” whose orientation relative to the posterior cranial base influences craniofacial shape among anthropoids in which orbital orientation influences the orientation of the anterior cranial base. One such effect is that increases in cranial base flexion shorten the antero‐posterior length of the nasopharynx. Anat Rec 264:247–260, 2001. © 2001 Wiley‐Liss, Inc.