bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractThe 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

AbstractTwo 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

AbstractTwo 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

AbstractPolyethylene (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

AbstractWe 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

AbstractPolypropylene/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

AbstractPoly(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

AbstractSex 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

AbstractFour 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

AbstractImidacloprid 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

AbstractThe 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

AbstractIdentifying 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

AbstractInhibition 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

AbstractEffects 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

AbstractGiven 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

AbstractThe 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.