bluuebunny/crossref_metadata_2025 huggingface dataset:
Recycling of EPDM waste. I. Effect of ground EPDM vulcanizate on properties of EPDM rubber
Authors: Jacob Ceni , De P. P. , Bhowmick A. K. , De S. K.
Published: October 2004

Processing, cure characteristics, and mechanical properties of EPDM rubber containing ground EPDM vulcanizate of known composition were studied. Mooney viscosity increases and Mooney scorch time decreases by the addition of the ground vulcanizate. At higher loadings of the ground rubber, the maximum rheometric torque decreases. On addition of ground waste, stress–strain properties and tear resistance increase, whereas heat buildup marginally increases, resilience marginally decreases, low‐strain modulus remains constant, and abrasion resistance decreases. The interplay between the filler effect of the ground EPDM and the crosslink density changes of the EPDM matrix is believed to be the reason for the variation in mechanical properties. It is believed that sulfur migration occurs from the raw EPDM matrix (R‐EPDM) to the ground waste EPDM (W‐EPDM) particle while accelerator migration occurs from W‐EPDM to R‐EPDM. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3293–3303, 2001
Reactivity of cyclosiloxane with 3,3,4,4,5,5,6,6,6‐nonafluorohexyl group and its application to fluorosilicone synthesis
Authors: Furukawa Yutaka , Shin‐Ya Seiji , Miyake Haruhisa , Kishino Hideharu , Yamada Minoru , Kato Hitoshi , Sato Masakuni
Published: October 2004

The reactivity of cyclosiloxane with 3,3,4,4,5,5,6,6,6‐nonafluorohexyl group and its application to fluorosilicone synthesis were studied. In contrast to the polymerization of the commercially available 1,3,5‐tris(3,3,3‐trifluoropropyl)‐1,3,5‐trimethylcyclotrisiloxane (CF3–D3), the polymerization of 1,3,5‐tris(3,3,4,4,5,5,6,6,6‐nonafluorohexyl)‐1,3,5‐trimethylcyclotrisiloxane (C4F9–D3) with sodium hydroxide yielded 1,3,5,7‐tetrakis(3,3,4,4,5,5,6,6,6‐nonafluorohexyl)‐1,3,5,7‐tetramethylcyclotetrasiloxane {[C4F9CH2CH2(CH3)SiO]4 (C4F9–D4)} as the major product, which was the result of the depolymerization by a backbiting mechanism. On the other hand, the polymerization of C4F9–D3 with trifluoromethanesulfonic acid yielded a polymer with good reproducibility, although the distribution of molecular weight tended to be bimodal. C4F9–D3 was also successfully copolymerized with octamethylcyclotetrasiloxane (D4). The properties of the obtained copolymers changed almost linearly with the amount of [C4F9C2H4(CH3)SiO] units, except for the surface tension. The surface tension of the copolymer containing more than 50% [C4F9C2H4(CH3)SiO] units by weight was almost as low as that of the homopolymer. When the copolymer containing 50% [C4F9C2H4(CH3)SiO] units by weight was examined for an antifoaming agent, it worked as effectively as the homopolymer in the toluene foaming system. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3333–3340, 2001
Cellulose phosphates as biomaterials. I. Synthesis and characterization of highly phosphorylated cellulose gels
Authors: Granja P. L. , Pouységu L. , Pétraud M. , De Jéso B. , Baquey C. , Barbosa M. A.
Published: October 2004

The present study concerns the investigation of a material expected to be biocompatible and able to promote bone regeneration. For this purpose, cellulose was chemically modified by phosphorylation. Once implanted, phosphorylated cellulose could promote the formation of calcium phosphates, thus having closer resemblance to bone functionality. In a previous investigation, the obtention and the preliminary characterization of cellulose phosphate gels were reported. In the present study, the synthesis by the H3PO4/P2O5/Et3PO4/hexanol method was optimized in terms of reaction parameters. The structure of materials was investigated by FTIR, Raman, and solid‐state 31P– and 13C–NMR spectroscopic studies, and X‐ray diffraction. Water swelling and stability to sterilization by gamma‐radiation were also assessed. It was demonstrated that the present method allows highly phosphorylated cellulose derivatives to be obtained. Cellulose triphosphates gels are described here for the first time. Products obtained were poorly crystallized monoesters, apparently not significantly affected by gamma sterilization and showed a high water swelling capability. Chemical bonding was confirmed by FTIR, Raman, and both 31P– and 13C–NMR spectroscopies. It was also shown that the H3PO4/P2O5/Et3PO4/hexanol method provides a versatile and interesting alternative route to some of the more widely used techniques for the phosphorylation of cellulose. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3341–3353, 2001
Cellulose phosphates as biomaterials. II. Surface chemical modification of regenerated cellulose hydrogels
Authors: Granja P. L. , Pouységu L. , Deffieux D. , Daudé G. , De Jéso B. , Labrugère C. , Baquey C. , Barbosa M. A.
Published: October 2004

Cellulose regenerated by the viscose process was previously investigated as an implantable material in orthopedic surgery. It was envisaged to take advantage not only of its good matching with mechanical properties of bone but also of its hydroexpansivity, therefore allowing a satisfactory fixation to hard tissue. Both the osteoconduction and the lack of osteoinduction of this material were demonstrated. Grafting of phosphate groups was then envisaged as the means to render cellulose more suitable for orthopedic applications by enhancing its bioactivity. In the present work, the previously optimized phosphorylation reaction was successfully adapted to the surface modification of regenerated cellulose. Modified materials were characterized by XPS, FTIR, and 31P MAS NMR spectroscopic studies, and contact angle measurements, revealing the chemical bond between phosphate groups and cellulose, as well as the hydrophilic nature of phosphorylated materials, which increases with increasing phosphate contents. Water swelling and resistance to gamma sterilization were assessed as well, showing that phosphorylated materials swell considerably in water and were not affected when sterilization was carried out under a nitrogen atmosphere. The increase in surface roughness attributed to chemical modification was demonstrated through laser rugosimetry measurements. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3354–3365, 2001
Effects of the molecular weight on the properties of thermoplastics prepared from soy protein isolate
Authors: Wu Qiangxian , Zhang Lina
Published: October 2004

Commercial soy protein isolate (SPI) was fractionated into four fractions by an acidifying method from pH 5.7 to 4.5 with 2M HCl. A mixture of SPI with glycerin (50 g/100 g of dry SPI) was compression‐molded to obtain thermoplastic sheets. The weight‐average molecular weight (Mw) of the fractions, the structure, and the mechanical properties of the thermoplastic SPI sheets were investigated with light scattering, IR spectroscopy, wide X‐ray diffraction patterns, differential scanning calorimetry, ultraviolet spectroscopy, scanning electron microscopy, and tensile testing. After heating compression, the SPI sheets were transparent and exhibited a smooth and homogeneous structure. Moreover, the crystallinity degree of the thermoplastic SPI was obviously higher than that of the premix before compression because of the formation of intermolecular hydrogen bonding. The Mw's of the fractions were 1.17 × 105 to 3.21 × 105, and they increased with increasing pH value in fractionation. The mechanical properties and water resistance (R) of the SPI sheets increased with increasing Mw of the SPI fractions. The tensile strength and breaking elongation of the SPI sheets with an Mw value of 3.21 ×105 were 5.7 MPa and 135%, respectively, and the R value was 0.54 after immersion in water for 15 days. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3373–3380, 2001
Properties of thermoplastic polyurethane elastomers chemically modified by rosin
Authors: Sánchez–Adsuar M. S. , Papon E. , Villenave J.‐J.
Published: October 2004

Thermoplastic polyurethane elastomers (TPUs) are prepared including different amounts of rosin in their composition. Rosin is used either as an additive, mixed in the TPU solutions, or as a reactant in the chain‐extension step of polymer synthesis. The properties of the materials are studied using solution viscosity measurements, size‐exclusion chromatography, stress‐controlled rheometry, differential scanning calorimetry, wide‐angle X‐ray diffraction, and contact angle determinations. Rosin as an additive does not markedly change the polymer properties. On the contrary, the use of rosin in the chain‐extension step leads to sharp increases of viscosity and molar mass as well as improvements of rheological properties and changes in morphology: the crystalline regions are more affected (variations in the softening temperature and enthalpy) than the amorphous ones (quite constant glass‐transition temperature). The conclusion is that rosin acts as an actual chain extender and that it modifies the organization of both the hard and the soft segments of the polymers. Furthermore, the TPUs are used as raw materials of solvent‐based adhesives, which adhesion properties are characterized by T‐peel tests of PVC/TPU adhesive joints. Rosin as an additive cannot improve the low tack (initial adhesive strength) of TPU, although as a chain extender or cochain extender (together with butane diol) rosin allows development of significant initial adhesive strengths, while keeping a high level of actual (maximal) adhesive strength. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3402–3408, 2001
Synthesis and characterization of novel sulfobetaines derived from 2,4‐tolylene diisocyanate
Authors: Lee Wen‐Fu , Chen Chin‐Fu , Yen Shih‐Hsun
Published: October 2004

Novel sulfobetaines were synthesized from two urethanes derived from 2,4‐tolylene diisocyanate (TDI) blocked with 2‐hydroxyethyl methacrylate (HEMA) and either N,N‐dimethylaminopropylamine (DMAPA) or N,N‐dimethylaminoethanolamine (DMAEA). The first‐stage reaction of TDI with HEMA was carried out in petroleum ether heterogeneously with the precipitation of the intermediate monoadduct product in the reaction solution. The second stage is a homogeneous reaction of the monoadduct with the blocking agent, DMAPA or DMAEA, in tetrahydrofuran (THF). In both reactions, an inhibitor, hydroquinone, and a catalyst, dibutyltin diacetate (DBDAc), were used. The tertiary amine urethanes were quaternized by 1,3‐propane sultone to form the two novel sulfobetaines. The results of the elemental analysis of those products along with their 1H‐NMR and IR spectra indicated that these materials were, indeed, the compounds expected. The products dissolved in strongly polar organic solvents. The copolymerization of these two monomers with comonomers such as styrene, methyl methacrylate, acrylamide, and HEMA was investigated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3447–3459, 2001
Effects of zone drawing on the structure of metallocene polyethylene
Authors: Berns David M. , Oyebode Elizabeth , Dair Benita , Cebe Peggy , Capel Malcolm
Published: October 2004

The influence of zone drawing on bulk properties and structure of metallocene polyethylene (m‐PE) is reported. Two different m‐PE materials were subjected to tensile stresses above the yield point by zone drawing in the temperature range from 50 to 100°C. Drawn materials were characterized by using small‐ and wide‐angle X‐ray scattering (SAXS, WAXS), molecular retraction, and small‐angle light scattering (SALS). Structural changes were studied as a function of drawing temperature, engineering stress, and draw ratio. WAXS showed strong crystalline orientation in drawn samples, and only the orthorhombic crystal modification was observed. SAXS showed lamellar orientation in drawn samples. At low drawing temperatures of 50 or 60°C, draw ratio increased as a step function of stress. There is a stress barrier, which must be exceeded before high‐draw ratios can be achieved at these temperatures. At drawing temperatures of 70°C or above, the barrier stress is low enough that draw ratio increases nearly linearly as a function of stress. Below the stress barrier, spherulitic structure is observed by small‐angle light scattering (SALS). Elongation occurs via deformation of the interspherulitic amorphous phase. Molecular retraction was low for these samples, indicating mostly plastic deformation of the amorphous material. Above the stress barrier, SALS showed that spherulites are destroyed. Elongation occurs via deformation of the intraspherulitic amorphous phase. Molecular retraction for these samples was high, indicating elastic deformation of the amorphous material. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3492–3504, 2001
Graft polymerization of methyl methacrylate onto guar gum with ceric ammonium sulfate/dextrose redox pair
Authors: Chowdhury P. , Samui S. , Kundu T. , Nandi M. M.
Published: October 2004

The effect of different reaction conditions on the grafting of methyl methacrylate (MMA) onto guar gum (GG) has been studied in detail. The grafting efficiency was optimal under the following conditions: MMA at 1.13 mol/L; ceric ammonium sulfate at 6.32 × 10−3 mol/L; dextrose monohydrate at 2.428 × 10−3 mol/L; GG at 4 g/L; temperature at 50°C; and time at 210 min. Fourier transform infrared spectroscopy was used for the confirmation of copolymer formation. Thermogravimetric analysis of GG and a representative graft copolymer were studied. A probable mechanism of grafting has been suggested. The biodegradability of the resulted copolymer was evaluated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3520–3525, 2001
Flame retardant epoxy polymers using phosphorus‐containing polyalkylene amines as curing agents
Authors: Jeng Ru‐Jong , Wang Jun‐Ren , Lin Jiang‐Jen , Liu Ying‐Ling , Chiu Yie‐Shun , Su Wen‐Chiung
Published: October 2004

Two series of novel phosphorus‐containing poly(alkylene) amines with or without aromatic groups were synthesized via reacting phosphoryl chloride derivatives with commercially available polyetheramines, ethylenediamine and N‐phenyl‐1,4‐phenylenediamine, respectively. Chemical structures of the amines were characterized with FTIR, NMR, P (phosphorus) content measurement, and amine content titration. These amines were then utilized as curing agents to react with diglycidyl ether of bisphenol A for preparing phosphorus containing epoxy polymers. The introduction of soft PO linkage, polyalkyene, and hard aromatic group into the backbones of the synthesized phosphorus‐containing amine (PCA) provides epoxy resins with tunable flexibility. Thermal analysis of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) reveals that these resulted epoxy resins possess moderate Tg's and thermal stability. Furthermore, high char yields in TGA and high limited oxygen index (LOI) values indicate that these phosphorus‐containing epoxy (PCE) resins are capable of exhibiting excellent flame retardant properties. These polymers can be potentially utilized in flame retardant epoxy coatings and other applications. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3526–3538, 2001
Cure behavior of epoxy resins with different kinds of onium salts as latent thermal catalysts
Authors: Lin Rong‐Hsien , Chen Chao‐Lin , Kao Li‐Heng , Yang Ping‐Rong
Published: October 2004

Two latent thermal catalysts, Dimethyl phenacylsulfonium hexafluoroantimonate, (Benzyl‐S), and triphenyl benzyl phosphonuim hexafluoroantimonate, (Benzyl‐P), were synthesized. Both these synthesized catalysts fulfill requirements for a rapid cure at a moderately elevated temperature in curing the epoxy resins of neat 3,4‐epoxycyclohexylmethyl‐3,4‐epoxycyclohexane‐carboxylate, (EPC), neat 2,2‐bis(4‐glycidyloxyphenyl)propane, (EPA), and their hybrid resin. The cure behavior of these resins cured individually with the synthesized catalysts was studied through correlation of the in situ FTIR (Fourier transform infrared) spectroscopy and DSC (differential scanning calorimetry) dynamic scanning results. Catalyst Benzyl‐S is more effective than Benzyl‐P. Resin EPC is significantly more sensitive to the latent thermal catalysts than the EPA resin. Activated chain‐end (ACE) and activated monomer (AM) mechanisms are basically adopted. Isomerization occurs in the neat EPA cure system, and transesterification takes place in all systems containing EPC species in the latter curing stage. Most importantly, ester linkages CO in the hybrid systems have been destroyed at some time during the curing process, but some reformed at the latter curing stage. It is most likely that the CO linkage in the EPC segments was attacked by the activated chain‐end of the epoxide group of EPA species to form a five‐membered cyclic acetal. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3539–3551, 2001
Morphology monitoring of PE/PBT blends by reactive processing
Authors: Pesneau I. , Cassagnau P. , Michel A.
Published: October 2004

Polyethylene (PE)/poly(butylene terephthalate) (PBT) blends were in situ compatibilized during a processing operation by the addition of a partially hydroxylated ethylene vinyl acetate copolymer (EVAh). This copolymer, obtained from ethylene vinyl acetate (EVA), was as compatible with PE as EVA was before modification. In the presence of EVAh, the dispersion of PBT in the PE matrix was finer, and the interfacial adhesion was improved. These results are relevant for the compatibilization of PE/PBT blends. Moreover, such blends present good toluene barrier properties. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3568–3577, 2001
Effect of annealing on electrical conductivity and morphology of polyaniline films
Authors: Lodha Anurag , Kilbey S. Michael , Ramamurthy Praveen C. , Gregory Richard V.
Published: October 2004

We report structure–property relationships of polyaniline emeraldine base (EB) films that were produced by combining different processing steps in various sequences. The effect of annealing and doping processes on the surface structure of the films was investigated by atomic force microscopy (AFM), and the corresponding changes to the chemical structure of the EB films were monitored by Fourier transform infrared spectroscopy. AFM results indicate that after doping polyaniline (EB) films with HCl, the root mean square (rms) roughness of the surface of EB film increased ∼ 46%. When the doped films were annealed at 180°C under a nitrogen atmosphere for 3 h, the rms roughness was essentially unchanged from that of the initial, undoped films. The electrical conductivity of the films also showed a significant dependence on the processing sequence. When the doped polyaniline (EB) films were annealed, no electrical conductivity was observed. When these films were redoped, only ∼ 6% of the initial conductivity could be recovered. In another processing sequence in which the polyaniline (EB) films were first annealed and then doped, the electrical conductivity was only ∼ 12% relative to the film that was doped immediately after being cast. From this work, a strategy to reduce the surface roughness of films made from electrically conducting polyaniline (EB) is proposed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3602–3610, 2001
Synthesis and characterization of polypropylene/clay nanocomposites
Authors: Ma Jisheng , Qi Zongneng , Hu Youliang
Published: October 2004

Polypropylene/clay (PP/clay) nanocomposites were synthesized via intercalative polymerization. The nanostructure of the composites was investigated by wide‐angle X‐ray diffractometry (WAXD) and transmission electron microscopy (TEM). The WAXD patterns of the PP/clay nanocomposites indicated that the characteristic diffraction peak of the clay disappeared. The TEM image showed the clay was exfoliated into nanometer size and dispersed uniformly in the PP matrix. The composites exhibited much higher storage modulus compared to that of pure PP. At temperatures higher than Tg, the storage modulus of the PP/clay nanocomposites with 8.1 wt % clay content increased three times that of the pure PP. Additionally, the thermal stability of the nanocomposites significantly increased. The maximum decomposition temperature was increased by 44°C with the introduction of about 10 wt % clay. The heat‐distortion temperatures (HDTs) of the nanocomposites also increased. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3611–3617, 2001
Crystallization behavior and mechanical properties of poly(ethylene oxide)/poly(L‐lactide)/poly(vinyl acetate) blends
Authors: Kim Kwang‐Sok , Chin In‐Joo , Yoon Jin San , Choi Hyoung Jin , Lee Dong Choo , Lee Kwang Hee
Published: October 2004

Poly(vinyl acetate) (PVAc) was added to the crystalline blends of poly(ethylene oxide) (PEO) and poly(L‐lactide) (PLLA) (40/60) of higher molecular weights, whereas diblock and triblock poly(ethylene glycol)–poly(L‐lactide) copolymers were added to the same blend of moderate molecular weights. The crystallization rate of PLLA of the blend containing PVAc was reduced, as evidenced by X‐ray diffraction measurement. A ringed spherulite morphology of PLLA was observed in the PEO/PLLA/PVAc blend, attributed to the presence of twisted lamellae, and the morphology was affected by the amount of PVAc. A steady increase in the elongation at break in the solution blend with an increase in the PVAc content was observed. The melting behavior of PLLA and PEO in the PEO/PLLA/block copolymer blends was not greatly affected by the block copolymer, and the average size of the dispersed PEO domain was not significantly changed by the block copolymer. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3618–3626, 2001
Stimulation of sex pheromone production by PBAN‐like substance in the pine caterpillar moth, Dendrolimus punctatus (Lepidoptera: Lasiocampidae)
Authors: Zhao Cheng‐Hua , Li Qun , Gao Wei
Published: October 2004

Sex pheromone production in the female pine caterpillar moth, Dendrolimus punctatus is controlled by a PBAN‐like substance located in the head of female moth. Pheromone titer was significantly decreased by decapitation of female moth, and restored by injection of either Hez‐PBAN or head extract prepared from male or female moth. Stimulation of pheromone production by head extract followed a dose‐dependent pattern from 0.5 to at least 4 head equivalent. A gland in vitro assay was used to study the relationship between gland incubation time and pheromone production as well as calcium involvement in the stimulation of pheromone production by head extract. Maximum pheromone production was occurred at 60 min after pheromone gland was incubated with two equivalents of head extracts. In vitro experiments showed that the presence of calcium in the incubation medium was necessary for stimulation of pheromone production. The calcium ionophore, A 23187, alone stimulated pheromone production. The pheromone components (Z,E)‐5,7‐dodecadienol and its acetate and propionate were produced in these experiments but in addition to the aldehyde, (Z,E)‐5,7‐dodecadienal was also found. This indicates that females are capable of producing four oxygenated functional groups. The PBAN‐like substance control of the pheromone biosynthetic pathway was investigated by monitoring the incorporation of the labeled precursor into both pheromone and pheromone intermediates.Arch. Insect Biochem. Physiol. 49:137–148, 2002. © 2002 Wiley‐Liss, Inc.
Identification of four additional myoinhibitory peptides (MIPs) from the ventral nerve cord of Manduca sexta
Authors: Blackburn Michael B. , Jaffe Howard , Kochansky Jan , Raina Ashok K.
Published: October 2004

Four new myoinhibitory peptides were isolated and identified from the ventral nerve cord of adult Manduca sexta. The new peptides are related to two previously identified myoinhibitory peptides also isolated from adult M. sexta, Mas‐MIP I and Mas‐MIP II. The sequences of the new peptides are APEKWAAFHGSWamide (Mas‐MIP III), GWNDMSSAWamide (Mas‐MIP IV), GWQDMSSAWamide (Mas‐MIP V), and AWSALHGAWamide (Mas‐MIP VI). Mas‐MIPs III‐VI were found to inhibit spontaneous peristalsis of the adult M. sexta anterior hindgut (ileum) in vitro. Arch. Insect Biochem. Physiol. 48:121–128, 2001. Published 2001 Wiley‐Liss, Inc.
Imidacloprid‐induced facilitation of the proboscis extension reflex habituation in the honeybee
Authors: Lambin M. , Armengaud C. , Raymond S. , Gauthier M.
Published: October 2004

Imidacloprid is a new insecticide from the family of the neonicotinoids, which interact with the insect nicotinic acetylcholine receptor. The effects of imidacloprid at a dose that does not affect sensory or motor functions are studied on non‐associative learning abilities in the honeybee. The behavioral procedure is the habituation of the proboscis extension reflex (PER). Imidacloprid topically applied on the thorax (1 μl) at the doses of 5, 10, and 20 ng/bee induces an increase of the gustatory threshold defined as the lowest concentration of a sucrose solution applied to the antennae able to elicit the PER. The ability of the honeybee to move in an open‐field‐like apparatus is impaired at the doses of 2.5, 5, 10, and 20 ng/bee. These effects are amplified with time and reach a maximum 60 min after application. The lowest dose of 1.25 ng/bee has no effect on the gustatory function but increases the motor activity and facilitates the PER habituation independently of time. This result fits our hypothesis that a slight activation of the cholinergic system with a low dose of imidacloprid can facilitate a simple form of learning in the honeybee. Arch. Insect Biochem. Physiol. 48:129–134, 2001. © 2001 Wiley‐Liss, Inc.
Provocation study of persons with perceived electrical hypersensitivity and controls using magnetic field exposure and recording of electrophysiological characteristics
Authors: Lyskov Eugene , Sandström Monica , Mild Kjell Hansson
Published: October 2004

The aim of the present study was to investigate possible neurophysiological effects of intermittent 15 sec on/off cycle, 60 Hz, 10 μT magnetic field exposure on patients with perceived “electromagnetic hypersensitivity” (EHS), and control subjects during rest and performance of a mental arithmetic task. Twenty participants (15 female, 5 male, 31–60 years old, mean 45.8 ± 0.7 years) were invited from the group of EHS patients. Twenty volunteers (15 female, 5 male, 31–59 years old, mean 45.0 ± 0.7 years?) served as a control group. The test protocol consisted of a set of examinations: EEG, visual evoked potentials, electrodermal activity, ECG, and blood pressure. The total duration of the test was 40 min, divided into two 10 min rest periods and two 10 min periods of mathematical performance. Magnetic field and sham exposures were presented randomly during these periods, resulting in four different conditions: Field‐Rest, Sham‐Rest, Field‐Math, and Sham‐Math. The data showed significant main effects of the Group factor (EHS vs. control subjects) on heart rate (F1,80 = 20.6; P < 0.01), heart rate spectrum ratio (F1,80 = 9.5; P = 0.02), and electrodermal activity (F1,76 = 4.2; P = 0.04), whereas EEG characteristics did not differ between groups. The Condition factor (mathematical task vs. relaxed) showed main effects for heart rate (F1,80 = 14.8; P < 0.01), heart rate spectrum ratio (F1,80 = 7.8; P = 0.06), electrodermal activity (F1,76 = 56.8; P < 0.01), and alpha and theta spectral bands of EEG. Magnetic field exposure did not affect autonomous system or electroencephalographic variables of either group. These data do not indicate that EHS patients or control are affected by low‐level 60 Hz magnetic field exposure. However, persons reporting EHS differed from the control subjects in baseline values of investigated physiological characteristics. Perhaps EHS patients have a rather distinctive physiological predisposition to sensitivity to physical and psychosocial environmental stressors. Bioelectromagnetics 22:457–462, 2001. © 2001 Wiley‐Liss, Inc.
Numerical computation of distortions in magnetic fields and induced currents in physiological solutions produced by microscope objectives
Authors: Chatterjee Indira , Hassan Noha , Craviso Gale L. , Publicover Nelson G.
Published: October 2004

Identifying distortions produced by commonly employed microscope objectives and their components in uniform DC and 60 Hz AC magnetic fields is important in imaging studies involving exposure of cells to spatially uniform or nonuniform magnetic fields. In this study, DC and 60 Hz AC magnetic flux densities were numerically computed in the presence of finite element models of various components of commonly utilized microscope objectives, as well as a model of a complete objective. Also computed were the distortions in the current density induced by an applied time‐varying magnetic field in a physiological buffer contained within a Petri dish. We show that the magnetic flux density could be increased up to 65% in the presence of the nickel–chrome plating of an objective housing and that the presence of ferromagnetic components like a screw or spring could produce peaks that are 7% higher than the undistorted value of magnetic flux density. In addition, a slight tilt of 1% in the objective with respect to the magnetic field could cause a 93% deviation in magnetic flux density from the unperturbed value. These results correlate well with previously published experimental measurements that showed the presence of significant and sometimes asymmetric distortions in both DC and 60 Hz magnetic fields. Moreover, this study further reports that induced current density changed up to 37% compared to values in the absence of the objective. The existence of distortions in applied magnetic fields and induced currents could affect the interpretation of results of cell function studies if it is assumed that the cells are exposed to uniform magnetic flux densities in the presence of a microscope objective. Such assumptions of uniform magnetic flux density could also account for the lack of reproducibility in several studies that examined changes in intracellular calcium by imaging techniques. Bioelectromagnetics 22:463–469, 2001. © 2001 Wiley‐Liss, Inc.
Direct current decreases cell viability but not P‐glycoprotein expression and function in human multidrug resistant leukemic cells
Authors: Holandino Carla , Veiga Venício F. , Rodrigues Marcio L. , Morales Marcelo M. , Capella Marcia A. M. , Alviano Celuta S.
Published: October 2004

Inhibition of tumor growth induced by treatment with direct current (DC) has been reported in several systems. In the current work, the cellular effects generated by the DC treatment of the human leukemic K562 cell line and its vincristine‐resistant derivative K562‐Lucena 1 were analyzed by trypan blue staining and transmission electron microscopy. DC stimulation induced cell lysis, alterations in shape, membrane extraction or discontinuity, and intense vacuolization of some cells. In addition, treatment of K562 and K562‐Lucena 1 cells caused a marked decrease in viability. Since multidrug resistance is a major factor contributing with failure of chemotherapy in many tumors, the expression and function of P‐glycoprotein (P‐gp) in K562‐Lucena 1 cells were also studied. The expression of mdr1, the gene encoding P‐gp, was analyzed by reverse transcription polymerase chain reaction, which showed that this gene was equally expressed in either treated or untreated cells. These results were confirmed by flow cytometry with a monoclonal anti P‐gp antibody and the Rhodamine 123 extrusion method, which revealed that P‐gp surface expression and function were unaltered after DC treatment. Our results suggest that DC treatment does not affect P‐gp in human leukemic cells, but affects their viability by mechanisms that would involve clear cellular effects, but also additional targets, whose relevance in dc treated tumoral cells is currently discussed. Bioelectromagnetics 22:470–478, 2001. © 2001 Wiley‐Liss, Inc.
Effects of permanent magnets on resting skin blood perfusion in healthy persons assessed by laser doppler flowmetry and imaging
Authors: Mayrovitz Harvey N. , Groseclose Edye E. , Markov Marko , Pilla Arthur A.
Published: October 2004

Effects on skin blood perfusion of permanent ceramic magnets [0.1 T (1000 G) surface field], individually (disk shaped, 4 cm diameter × 1 cm thick) or in the form of a 11 × 7 in pad (∼28 × 17.8 cm) with an array of 16 rectangular magnets (4.5 × 2.2 cm), were investigated in 16 female volunteers (27.4 ± 1.7 years, range 21–48 years) using three separate protocols. In protocol A, a disk magnet was placed on the palmar surface of the hand in contact with the thenar eminence (n = 5). In protocol B, the magnet was placed on the hand dorsum overlying the thenar eminence (n = 5). In protocol C, the entire palm and fingers rested on the magnetic pad (n = 6). Magnets were in place for 36 min on one hand, and a sham was in place on the other hand. Blood perfusion was measured on the middle finger dorsum by laser Doppler flowmetry (LDF) and on the index finger by laser Doppler imaging (LDI). Perfusion measurements were simultaneously taken in sham and magnet exposed hands, before and during the entire magnet exposure interval. Magnetic field effects were tested by comparing skin blood perfusion sequences in magnet and sham exposed regions. Results showed no significant changes in either LDF or LDI perfusion at magnet or sham sites during exposure, nor were there any significant differences between sham and magnet sites for any protocol. Measurements of skin temperature at the LDF measurement sites also showed no significant change. It is concluded that in the healthy subjects studied with normal, unstressed circulation, magnets of the type and for the duration used, showed no detectible effect on skin blood perfusion in the anatomical area studied. Bioelectromagnetics 22:494–502, 2001. © 2001 Wiley‐Liss, Inc.
Green function method for calculating properties of static magnetic fields
Authors: Engström Stefan
Published: October 2004

Given complete information about the normal component of a magnetic field in a plane, it is possible to directly calculate all aspects of the field at any point in a source‐free, homogeneous volume above that plane. The magnetic scalar potential, the magnetic field, and its gradient have direct representations as integrals of the boundary data. This paper provides a Green function method for this problem, as well as examples of such calculations. Bioelectromagnetics 22:511–518, 2001. © 2001 Wiley‐Liss, Inc.
Electromagnetic field of mobile phones affects visual event related potential in patients with narcolepsy
Authors: Jech Robert , Šonka Karel , Růžička Evžen , Nebuželský Antonín , Böhm Jiří , Juklíčková Michaela , Nevšímalová Soňa
Published: October 2004

The effects of the mobile phone (MP) electromagnetic fields on electroencephalography (EEG) and event‐related potentials (ERP) were examined. With regard to the reported effects of MP on sleep, 22 patients with narcolepsy‐cataplexy were exposed or sham exposed for 45 min to the MP (900 MHz, specific absorption rate 0.06 W/kg) placed close to the right ear in a double blind study. There were no changes of the EEG recorded after the MP exposure. A subgroup of 17 patients was studied on visual ERP recorded during the MP exposure. Using an adapted “odd‐ball” paradigm, each patient was instructed to strike a key whenever rare target stimuli were presented. There were three variants of target stimuli (horizontal stripes in (i) left, (ii) right hemifields or (iii) whole field of the screen). The exposure enhanced the positivity of the ERP endogenous complex solely in response to target stimuli in the right hemifield of the screen (P < 0.01). The reaction time was shortened by 20 ms in response to all target stimuli (P < 0.05). In conclusion, the electromagnetic field of MP may suppress the excessive sleepiness and improve performance while solving a monotonous cognitive task requiring sustained attention and vigilance. Bioelectromagnetics 22:519–528, 2001. © 2001 Wiley‐Liss, Inc.
Transport and arrangement of the outer‐dynein‐arm docking complex in the flagella of Chlamydomonas mutants that lack outer dynein arms
Authors: Wakabayashi Ken‐ichi , Takada Saeko , Witman George B. , Kamiya Ritsu
Published: October 2004

The outer dynein arms of Chlamydomonas flagella are attached to a precise site on the outer doublet microtubules and repeat at a regular interval of 24 nm. This binding is mediated by the outer dynein arm docking complex (ODA‐DC), which is composed of three protein subunits. In this study, antibodies against the 83‐ and 62‐kD subunits (DC83 and DC62) of the ODA‐DC were used to analyze its state of association with outer arm components within the cytoplasm, and its localization in the axonemes of oda mutants. Immunoprecipitation indicates that DC83 and DC62 are preassembled within the cytoplasm, but that they are not associated with outer arm dynein. Both proteins are lost or greatly diminished in oda1 and oda3, mutants in the structural genes of DC62 and DC83, respectively, demonstrating that their association is necessary for their stable presence in the cytoplasm. Immunoelectron microscopy indicates that DC83 repeats at 24‐nm intervals along the length of the doublet microtubules of oda6, which lacks outer arms; thus, outer arm periodicity may be determined by the ODA‐DC. Flagellar regeneration and temporary dikaryon experiments indicate that the ODA‐DC can be rapidly transported into the flagellum and assembled on the doublet microtubules independently of the outer arms and independently of flagellar growth. Unexpectedly, the intensity of ODA‐DC labeling decreased toward the distal ends of axonemes of oda6 but not wild‐type cells, suggesting that the outer arms reciprocally contribute to the assembly/stability of the ODA‐DC. Cell Motil. Cytoskeleton 48:277–286, 2001. © 2001 Wiley‐Liss, Inc.
Colour‐imager characterization by parametric fitting of sensor responses
Authors: Thomson M. , Westland S.
Published: October 2004

This study describes a novel method for characterizing the colorimetric and photometric properties of three‐channel color imaging devices. The method is designed to overcome some undocumented aspects of the imager‐characterization problem: The effective spectral sensitivity profiles of the imager's color channels depend on the level of radiant input energy, and these profiles must be known in order to determine the true intensity‐response characteristics of the three channels. By fitting the response distributions of the three color channels explicitly with low‐dimensional models, the method takes these dependencies into account, and may, therefore, offer several advantages over other imager‐characterization methodologies, particularly where illuminant‐independent characterization is required. An application of the technique is detailed, in which a CCD camera is characterized using only the Macbeth ColorChecker and a number of artificial illuminants. © 2001 John Wiley & Sons, Inc. Col Res Appl, 26, 442–449, 2001
Effects of thalidomide and 3‐phthalimido‐3‐(3,4‐dimethoxyphenyl)‐propanamide on bile duct obstruction‐induced cirrhosis in the rat
Authors: Fernández‐Martínez Eduardo , Morales‐Ríos Martha S. , Pérez‐Álvarez Víctor , Muriel Pablo
Published: October 2004

Tumor necrosis factor‐alpha (TNF‐α) plays a central role in cellular necrosis, apoptosis, organ failure, tissue damage, inflammation, and fibrosis. These processes, occurring in liver injury, may lead to cirrhosis. Thalidomide and its analogs have shown to be effective TNF‐α inhibitors. The aim of this work was to synthesize a thalidomide analog, the 3‐phthalimido‐3‐(3,4‐dimethoxyphenyl)‐propanamide (PDP) and to evaluate its hepatoprotective properties on bile duct obstruction‐induced cirrhosis. Synthesis, purification, and spectroscopic characterization of PDP were carried out. Thalidomide (200 mg/kg) or PDP (15 mg/kg) were administered to sham (Sh) or bile duct ligated (BDL) rats. The animals were sacrificed 28 days after treatments. Alkaline phosphatase (Alk. Phosph.), γ‐glutamyl transpeptidase (γ‐GTP) and alanine aminotransferase (ALT) enzyme activities, bilirubins, and TNF‐α concentrations were evaluated in plasma. Collagen was estimated by the liver hydroxyproline content and histopathology was performed. Both drugs showed partial amelioration of cirrhosis. However, the hepatoprotective effects of thalidomide were poor when compared to those afforded by PDP. While PDP improved the majority of the biochemical markers of liver injury and prevented partial but significantly collagen accumulation, thalidomide showed only modest beneficial effects on bilirubins and ALT. PDP was effective in preventing the increase in plasma TNF‐α levels, while thalidomide not only failed to inhibit TNF‐α, but increased it. Differences between thalidomide and PDP effectiveness may be due to their stability and different mechanism of action, as reported by others. Inhibition of proinflamatory cytokines is an interesting pharmacological aim to treat cirrhosis. Drug Dev. Res. 54:209–218, 2001. © 2002 Wiley‐Liss, Inc.
Comparative biodistribution of thin‐coated iron oxide nanoparticles TCION: Effect of different bisphosphonate coatings
Authors: Portet David , Denizot Benoît , Rump Elmar , Hindre François , Le Jeune Jean‐Jacques , Jallet Pierre
Published: October 2004

Because the nature of their coatings influences the biodistribution of nanocolloids, five different bisphosphonates bearing OH, NH2, NMe2, and N+Me3 groups were evaluated in vivo. 59Fe‐labeled iron cores were coated by the different molecules and tested by intravenous injection to healthy adult male Wistar rats. The initial phase was estimated with 59Fe‐ and 99mTc‐labeled nanoparticles biodistribution. The different coatings do not change hydrodynamic radius (∼12 nm) and relaxivities. The negative surface charge is half for particles coated with bisphosphonates bearing quaternary ammonium compared to those bearing a hydroxyl function. Nanoparticle vascular initial half disappearance time range between 25 and 39 min, with hepatic capture between 50 and 80% ID at 18 h. Bones and muscles fix globally around 35 % ID at 18 h, with high concentrations in the mineral bones. Hydroxy‐bisphosphonates and quaternary ammonium‐bisphosphonate‐coated nanoparticles are the most efficient for blood remanence, weak liver capture, and bone targeting. Drug Dev. Res. 54:173–181, 2001. © 2002 Wiley‐Liss, Inc.
Role of caspases in neuronal apoptosis
Authors: Ventimiglia Roseann , Lau Lit‐Fui , Kinloch Ross A. , Hopkins Andrew , Karran Eric H. , Petalidis Lawrence P. , Ward Robin V.
Published: October 2004

Caspases play a key role in the integration of specific cellular signaling events that ultimately result in apoptosis or “programmed cell death.” Apoptosis plays an important role during development and in normal cellular homeostasis. However, the inappropriate triggering of apoptotic pathways can have severe consequences that may contribute either directly or indirectly to a number of pathologies. Recognition of the key role of caspases in the apoptotic process has led a number of pharmaceutical and biotechnology companies to pursue the development of specific caspase inhibitors as therapeutic agents. However, no drug targeting this mechanism has yet been marketed. In this review we reflect on the role of caspases in a number of neuronal disorders and neurodegenerative diseases. We also review recent progress in the generation of caspase inhibitors and the challenges faced in their development as therapeutic agents for neurological indications. Drug Dev. Res. 52:515–533, 2001. © 2001 Wiley‐Liss, Inc.
Role of p‐21‐activated kinases in cell survival and apoptotic pathways
Authors: Schürmann Annette , Bokoch Gary M.
Published: October 2004

A balance between cell survival and cell death is necessary for multicellular organisms to maintain homeostasis. The family of p21‐activated kinases (PAKs 1, 2, and 3) are Rho GTPase‐regulated serine/threonine kinases implicated in the regulation of a variety of cellular processes. The aim of this review is to describe two mechanisms by which PAKs can influence cellular homeostasis. PAK2 is proteolytically cleaved and activated by caspases after stimulation of death receptors; this activation is implicated in the regulation of biochemical and morphological changes during apoptosis. PAK1 is activated by cell survival factors (for example, interleukin 3) and promotes survival via phosphorylation and inactivation of the pro‐apoptotic Bcl‐2 family member Bad. Drug Dev. Res. 52:542–548, 2001. © 2001 Wiley‐Liss, Inc.
Gastric surgery and restraint from food as triggering factors of eating disorders in morbid obesity
Authors: Guisado Juan A. , Vaz Francisco J. , López‐Ibor Juan J. , Inés López‐Ibor M. , del Río Julia , Rubio Miguel A.
Published: October 2004

Obese patients may share some clinical features with anorexia nervosa patients because they risk developing an eating disorder when they diet.

Methods and Results

Some common etiological, psychological, and social factors have been proposed for both disorders. We present two cases of patients suffering from morbid obesity who, after weight loss, presented an intense fear of regaining weight and developed anorexic‐like symptoms. In the first case, the symptoms appeared after gastric reduction surgery. In the second case, a strict diet was the triggering factor.

Discussion

This paper stresses the need for psychiatric evaluation of all patients with morbid obesity who seek treatment in clinical settings, in order to identify the factors that may lead to psychiatric complications. © 2002 by John Wiley & Sons, Inc. Int J Eat Disord 31: 97–100, 2002.
Filter banks for less ringing artifacts
Authors: Asano Wataru , Takeuchi Tomoaki , Ikehara Masaaki
Published: October 2004

In image compression using a filter bank, blocking can be reduced by overlapping the basis functions in the lapped orthogonal transform or the lapped biorthogonal transform, whereas ringing can be conspicuous. In this paper, two methods are proposed to suppress ringing while blocking is reduced. One of them uses an unequal length linear phase biorthogonal filter bank. This is an extension of the unequal length orthogonal transform to the biorthogonal type and a generalization of the filter length in the lapped biorthogonal transform. This filter bank can be realized with a lattice structure. By reducing the length of the high‐frequency filter on the synthesis side, ringing is compressed to the edge so that it is less visible. Another method introduces the peak‐to‐peak ratio into the performance criterion of the filter bank design. In this method, ringing can be suppressed by restricting the impulse response of the filter. By means of these methods, ringing can be reduced while coding performance is retained in comparison with the conventional equal length filter banks. © 2002 Scripta Technica, Electron Comm Jpn Pt 3, 85(6): 1–10, 2002
An Imanishism‐based genetic algorithm for sampling various Pareto‐optimal solutions: An application to the multiobjective resource division problem
Authors: Tagawa Kiyoharu , Wakabayashi Noboru , Haneda Hiromasa , Inoue Katsumi
Published: October 2004

For sampling various solutions from the entire Pareto front of the multiobjective resource division problem, a new Genetic Algorithm (GA) based on an evolutionary theory advocated by Kinji Imanishi is proposed. First, two types of distance between two individuals, namely, structural and functional distances, are introduced and used to define four types of relation between them, namely, homogeneous, heterogeneous, homologous, and analogous species. Then, for keeping a variety of species within a population as far as possible, a new generation alternation model with variable population size is presented. In order to find Pareto‐optimal solutions effectively, a new genetic operation that combines conventional harmonic crossover with a local optimization algorithm is also proposed. Finally, the advantage of the Imanishism‐based GA is demonstrated through computational experiments conducted on two‐ and three‐objective problem instances. © 2002 Scripta Technica, Electr Eng Jpn, 139(2): 23–35, 2002; DOI 10.1002/eej.10010