bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fine structure of poly(vinylidene fluoride) membranes prepared by phase inversion from a water/N‐methyl‐2‐pyrollidone/poly(vinylidene fluoride) system
Authors: Lin Dar‐Jong , Chang Cheng‐Liang , Chang Chi‐Lin , Chen Tzung‐Chin , Cheng Liao‐Ping 
Published: January 2004

AbstractPoly(vinylidene fluoride) (PVDF) membranes were prepared by the isothermal immersion and precipitation of PVDF/N‐methyl‐2‐pyrollidone dope solutions in either harsh or soft nonsolvent baths. Low‐voltage field emission scanning electron microscopy imaging of the formed membranes at high magnifications (e.g., 300,000×) revealed their nanoscale fine structures, particularly dendrites observed on the surfaces of the macrovoids, cellular pores, and the membrane skin, which have never been successfully presented in the literature. Evidence of crystallization was also demonstrated by X‐ray diffraction and differential scanning calorimetry measurements. The phase diagram at 25 °C, including a binodal, tie lines, and a crystallization‐induced gelation line, was determined both experimentally and theoretically. These results were further used in mass‐transfer calculations to obtain diffusion trajectories and concentration profiles for the membrane region, which were useful for elucidating the relationship between the membrane preparation conditions and the obtained membrane morphologies. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 830–842, 2004
Nanoindentation studies of polyimide thin films with various internal linkages in the diamine component
Authors: Lee Choonkeun , Kwon Jinuk , Park Sunggook , Sundar Saimani , Min Byoungryul , Han Haksoo 
Published: January 2004

AbstractPolyimide thin films were synthesized from 3,3′,4,4′‐biphenyltetracarboxylic acid dianhydride (BPDA) and four different diamines (p‐phenylene diamine, 4,4′‐oxydiphenylene diamine, 4,4′‐biphenylene diamine, and 4,4′‐sulfonyldiphenylene diamine). The nanoindentation behavior of the resulting polyimides, namely, poly(p‐phenylene biphenyltetracarboximide) (BPDA‐PDA), poly(4,4′‐biphenylene biphenyltetracarboximide) (BPDA‐BZ), poly(4,4′‐oxydiphenylene biphenyltetracarboximide) (BPDA‐ODA), and poly(4,4′‐sulfonyldiphenylene biphenyltetracarboximide) (BPDA‐DDS), were investigated. Also, the morphological properties were characterized with a prism coupler and wide‐angle X‐ray diffraction and were correlated to the nanoindentation studies. The nanoindentation behavior and hardness varied quite significantly, depending on the changes in the chemical and morphological structures. The hardness of the polyimide thin films increased in the following order: BPDA‐DDS < BPDA‐ODA < BPDA‐BZ < BPDA‐PDA. For all the polyimide thin films, except that of BPDA‐BZ, the hardness decreased with an increase in the load. The birefringence, a measure of the molecular in‐plane orientation, increased in the following order: BPDA‐DDS < BPDA‐ODA < BPDA‐PDA < BPDA‐BZ. The X‐ray diffraction studies revealed that the crystallinity of the polyimide thin films varied with the changes in the chemical structure. The studies showed that the indentation response with an applied load and the hardness by nanoindentation for the BPDA‐based polyimides were closely related to the morphological structure. The nanoindentation and birefringence results revealed that the mechanical properties of the polyimide thin films were dependent on the crystallinity, which arose because of the chain order along the chain axis and the molecular packing order. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 861–870, 2004
Effect of the water state on the electrical bending behavior of chitosan/poly(diallyldimethylammonium chloride) hydrogels in NaCl solutions
Authors: Kim Seon Jeong , Yoon Seoung Gil , Kim Sun I. 
Published: January 2004

AbstractSemi‐interpenetrating polymer network (SIPN) hydrogels, composed of chitosan (CS) and poly(diallyldimethylammonium chloride) (PDADMAC), were prepared, and they exhibited electrically sensitive behavior. The swelling behavior of the CS/PDADMAC SIPN hydrogels was studied through the immersion of the gels in various concentrations of aqueous NaCl solutions, and their responses to stimuli in electric fields were also investigated. When the swollen SIPN hydrogels were placed between a pair of electrodes, they exhibited bending behavior upon the application of an electric field, which was stepwise and dependent on the magnitude of the field. To clarify the relationship between the equilibrium‐swelling ratio and the bending behavior of the SIPN hydrogels, the state of water in the SIPN hydrogels was also investigated with differential scanning calorimetry. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 914–921, 2004
Optical investigation of GaAs1−xNx/GaAs heterostructure properties
Authors: Saidi F. , Hassen F. , Maaref H. , Auvray L. , Dumont H. , Monteil Y. 
Published: January 2004

AbstractWe have investigated, by photoluminescence (PL), the optical properties of GaAs1−xNx/GaAs epilayers and GaAs1−xNx/GaAs quantum well (QW) structures grown by metal organic vapor phase epitaxy (MOVPE) on (001)‐oriented GaAs substrates. Different behaviors have been observed for the bulk epilayer and for the QW structures, respectively: (i) a blue shift of the PL bands in both kinds of structures when increasing the excitation density, (ii) an S‐shaped PL peak energy versus temperature dependence has been observed for the GaAsN epilayer but a usual behavior is obtained for the QWs. Based in these experimental results, we have suggested that the carrier recombination mechanisms in the epilayer and in the quantum well structure are different. An enhanced exciton‐localization‐like mode for the epilayer is observed. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Superconducting and Vickers hardness properties of ZnO‐added YBCO polycrystalline superconductors
Authors: Kölemen U. , Çelebi S. , Karal H. , Öztürk A. , Çevik U. , Nezir S. , Görür O. 
Published: January 2004

AbstractThe effects of ZnO addition on the microstructure and mechanical properties of the YBCO have been investigated through XRD, SEM, EDX, ac susceptibility measurements and the standard Vickers microhardness testing method. We have prepared the samples by a conventional solid‐state reaction method and used an additive method for the YBCO system (0, 0.5 and 1 wt% of ZnO). The orthorhombic strain Δ = (b – a)/(b + a) increases as the Zn content increases, where a and b are the relevant lattice parameters of the samples. The superconducting transition temperatures and hardness depend on the Zn content of the samples. The hardness is found to be load dependent. From the relation between applied load F and the square of the impression diagonal, d2, the true hardness, H0, and the dissipative portion of the indentation load F0, were derived from the slope and the intercept (at d2 = 0) of the straight line, respectively. The hardness was increased while the transition temperature decreased with the amount of ZnO addition to YBCO. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Screw dislocation in two dissimilar piezoelectric layers
Authors: Liu Jin‐xi 
Published: January 2004

AbstractThe elastic and electrical fields produced by a straight screw dislocation in two dissimilar piezoelectric layers are derived through the use of conformal mapping technique, where the solution for a semi‐infinite piezoelectric bimaterial is used as a base. The expression for the image force acting on the dislocation is given explicitly. The equilibrium position of the dislocation is further determined by letting the image force be equal to zero. In the case where one of the two layers is pure elastic, the numerical results for the image force are provided to illustrate the influence of piezoelectric effect on the behavior of the dislocation. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Evolution of molecular ordering and phase transitions in C60/C70solid solutions
Authors: Rueda‐Morales Gabriela , Ortiz‐López Jaime 
Published: January 2004

AbstractPolycrystalline solid solutions (C60)x:(C70)1−xwith 0 ≤x≤ 1 grown by sublimation are studied with AC calorimetry in the 5–300 K temperature range and with X‐ray powder diffraction at room temperature. For concentrations 0.15 ≤x≤ 0.68, an hexagonal disordered (hcp) single phase is found at room temperature with no evidence of phase transitions occurring down to 5 K. This is indication of complete C60/C70miscibility and of freezing of orientational disorder at low temperature for this concentration range. Phase transitions below room temperature are detected only for concentrations close to the pure fullerenes, with critical temperatures decreasing asxdeparts away fromx= 0 and 1. The elastic dipole model is applied in pure C70and C70‐rich solid solutions to account for elastic interactions and ferroelastic ordering of the elongated C70molecule. Within this model, the evolution of ferroelastic phase transitions in C70‐rich solid solutions is obtained and compared with available experimental data. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of Rhus coriaria L. (Anacardiaceae) on lipid peroxidation and free radical scavenging activity
Authors: Candan Ferda , Sökmen Atalay 
Published: January 2004

AbstractIn order to evaluate the antioxidant potential of Rhus coriaria L. (Anacardiaceae), a well‐known spice, the methanolic extract (water‐soluble part) was prepared and investigated using free radical‐generating systems in vitro. The IC50 value of the extract for lipid peroxidation was estimated as 1200 µg/mL in the Fe+2‐ascorbate system while those for superoxide‐scavenging activity in the xanthine‐xanthine oxidase method and hydroxyl radical scavenging activity in the deoxyribose decomposition method were 282.92 µg/mL and 3850 µg/mL, respectively. These data suggest that the methanolic extracts of Rhus coriaria L. fruits have considerable antioxidant activity against free radicals and lipid peroxidation in vitro, a fact that may encourage in vivo studies. Copyright © 2004 John Wiley & Sons, Ltd.
The evaluation of the radioprotective effect of chyavanaprasha (an ayurvedic rasayana drug) in mice exposed to lethal dose of γ‐radiation: a preliminary study
Authors: Jagetia Ganesh Chandra , Baliga Manjeshwar Shrinath 
Published: January 2004

AbstractThe effect of various doses of 50% ethanolic extract of chyavanaprasha (an Ayurvedic rejuvenating herbal preparation) was studied on the survival of mice exposed to 10 Gy of γ‐radiation. Treatment with chyavanaprasha, consecutively for ﬁve days before irradiation, delayed symptoms of radiation sickness and onset of mortality when compared with the non‐drug treated irradiated controls. All doses of chyavanaprasha provided a signiﬁcant protection against gastrointestinal (GI) death (death of animals within 10 days after exposure to radiation), however, highest protection against GI death was observed for 15 mg/kg chyavanaprasha. Chyavanaprasha also provided a signiﬁcant protection against the bone marrow death after 10 to 40 mg/kg. However, the best protection was seen for 15 mg/kg, where the highest number of survivors was observed at the end of 30 days post‐irradiation. The drug was non‐toxic up to a dose of 6 g/kg b. wt., the highest drug dose that could be tested. Our study demonstrates that chyavanaprasha can provide good radioprotection at a very low non‐toxic dose. Copyright © 2004 John Wiley & Sons, Ltd.
Effects of methanol extract of Cirsium japonicum var. ussuriense and its principle, hispidulin‐7‐O‐neohesperidoside on hepatic alcohol‐metabolizing enzymes and lipid peroxidation in ethanol‐treated rats
Authors: Park Jong Cheol , Hur Jong Moon , Park Ju Gwon , Kim Sang Cheol , Park Jeong Ro , Choi Seong Hee , Choi Jong Won 
Published: January 2004

AbstractEffects of the methanol extract of Cirsium japonicum var. ussuriense and hispidulin 7‐O‐neohesperidoside isolated from the plant on hepatic alcohol‐metabolizing enzymes and lipid peroxidation were studied in rats treated with ethanol. Rats treated with 10% alcohol solution for 6 weeks were orally administered with 250 or 500 mg of methanol extract or 10 or 20 mg of hispidulin 7‐O‐neohesperidoside per kg body weight daily during the last week of ethanol treatment. The administration of the methanol extract of herbal plant and hispidulin 7‐O‐neohesperidoside in ethanol‐treated rats signiﬁcantly enhanced the activities of hepatic alcohol dehydrogenase, microsomal ethanol‐oxidizing system and aldehyde dehydrogenase in a dose‐dependent manner. The extract and the compound decreased hepatic lipid peroxidation along with an increase in hepatic content of reduced glutathione. The methanol extract and hispidulin 7‐O‐neohesperidoside of C. japonicum var. ussuriense also increased the activity of glutathione reductase, but had no effect on γ‐glutamylcysteine synthase. The results suggest that C. japonicum var. ussuriense may alleviate alcoholic toxicity by enhancing ethanol oxidation as well as inhibiting lipid peroxidation, and hispidulin 7‐O‐neohesperidoside is one of the active substances responsible for the protective effects of this plant. Copyright © 2004 John Wiley & Sons, Ltd.
Isolation and puriﬁcation of the hypoglycaemic principle present in Capsicum frutescens
Authors: Tolan Ian , Ragoobirsingh Dalip , Morrison Errol Y. St. A. 
Published: January 2004

AbstractCapsicum frutescens has been used to treat diabetes mellitus by traditional healers in Jamaica. Puriﬁcation experiments employing thin layer chromatography (TLC) and high performance liquid chromatography led to the extraction of the active principle, capsaicin. Puriﬁed capsaicin caused a decrease in blood glucose levels to 4.91 ± 0.52 (n = 6) mmol/dL versus 6.40 ± 0.13 mmol/dL (n = 6) for the control (p < 0.05) at 2.5 h in an OGTT in dogs. There was a concomitant elevation in plasma insulin levels (p < 0.05). In conclusion, it can be stated that capsaicin is the major constituent of Capsicum frutescens that is responsible for the hypoglycaemic episodes seen in the dogs. It is also apparent that the latter is mediated by insulin release. Copyright © 2004 John Wiley & Sons, Ltd.
Antiosteoporotic activity of OST‐6(Osteocare), a herbomineral preparation in calcium deﬁcient ovariectomized rats
Authors: Reddy N. Prabhakara , Lakshmana M. , Udupa U. Venkatesh 
Published: January 2004

AbstractThe preventive effect of the herbal formulation OST‐6 (Osteocare) on the progress of bone loss induced by ovariectomy and concurrent calcium deﬁciency was studied in rats. Ovariectomy (OVX) and calcium deﬁciency (CD) resulted in bone loss as evident from decreased femoral weight and density. Treatment with OST‐6 at a dose of 250 mg/kg body wt twice a day orally for a period of 16 weeks signiﬁcantly restored the femoral weight and density. The biomechanical strength of the tibia was decreased by OVX and CD and this was signiﬁcantly suppressed by the administration of OST‐6. Histologically decalciﬁed bone sections revealed narrowed, and the disappearance of, trabeculae and widened medullary spaces. The total numbers of tartrate‐resistant acid phosphates (TRAP) positive cells were increased signiﬁcantly in OVX animals. Treatment with OST‐6 signiﬁcantly inhibited these histopathological changes and strongly suggested that OST‐6 was effective in preventing the progress of bone loss induced by ovariectomy and concurrent calcium deﬁciency. Copyright © 2004 John Wiley & Sons, Ltd.
Chemical and biological evaluation of the essential oils of different Melaleuca species
Authors: Farag R. S. , Shalaby A. S. , El‐Baroty G. A. , Ibrahim N. A. , Ali M. A. , Hassan E. M. 
Published: January 2004

AbstractThe essential oils of the fresh leaves of M. ericifolia, M. leucadendron, M. armillaris and M. styphelioides were isolated by a hydrodistillation method and analysed by a gas chromatography/mass spectrometry (GC/MS) technique. The essential oil of M. ericifolia contained methyl eugenol (96.84%) as a major constituent, whereas M. leucadendron was rich in 1,8‐cineole (64.30%). The essential oil of M. armillaris was rich in 1,8‐cineole (33.93%) followed by terpinen‐4‐ol (18.79%), whereas M. styphelioides was rich in caryophyllene oxide (43.78%) and (‐) spathulenol (9.65%). The essential oils of these species possessed antimicrobial and antifungal activities. M. ericifolia exhibited the highest inhibitory effects against Bacillus subtiles and Aspergillus niger. The antiviral activities of the essential oils against Herpes simplex virus type 1 (HSV‐1) were studied in African green monkey kidney cells (Vero) by a plaque reduction assay. The volatile oil of M. armillaris was more effective as a virucidal (up to 99%) than that of M. leucadendron (92%) and M. ericifolia (91.5%). The effects of the essential oils on the antioxidant system status in carbon tetrachloride treated animals were studied. The essential oil of M. armillaris exhibited a marked antioxidant effect, it improved vitamin E, vitamin C and superoxide dismutase parameters so it can be used as a free radical suppressor. Copyright © 2004 John Wiley & Sons, Ltd.
Effect of garlic oil on ethanol induced gastric ulcers in rats
Authors: Khosla P. , Karan R. S. , Bhargava V. K. 
Published: January 2004

AbstractGarlic oil was evaluated for gastroprotective activity against ethanol induced ulcers. Reactive oxygen species are involved in the pathogenesis of these ulcers. The possible involvement of garlic oil in restraining the oxidation process produced in gastric tissue was also investigated. The ulcer index, lipid peroxidation and antioxidant enzyme activity (GPx, catalase, SOD) were determined. Pretreatment with garlic oil in doses of 0.25 and 0.5 mg/kg, 30 min before administration of ethanol (1 mL of 100%) caused a decrease in ulcer index and lipid peroxidation and ameliorated the decrease in antioxidant enzyme levels caused by ethanol. The result suggests that garlic oil possesses antioxidant properties and provides protection against ethanol induced gastric injury. Copyright © 2004 John Wiley & Sons, Ltd.
Vasodilating properties of the stem bark extract of Mitragyna ciliata in rats and guinea pigs
Authors: Dongmo A. , Kamanyi M. A. , Tan P. V. , Bopelet M. , Vierling W. , Wagner H. 
Published: January 2004

AbstractMitragyna ciliata is commonly used in traditional medicine for the treatment of inﬂammation, hypertension, headache, rheumatism, gonorrhoea and broncho‐pulmonary diseases. In the present study, the vascular relaxant effect in the rat and guinea‐pig was investigated. The extract induced aortic relaxation in a concentration‐dependent manner, with an EC50 of 1.3 and 7 µg/mL for the noradrenaline‐ and KCl‐induced contractions, respectively. The relaxant effect of the extract on KCl‐induced contractions was ﬁve times greater than on noradrenaline‐induced contractions. Moreover, the relaxant effect of the extract was higher in rat aortic rings with endothelium (104.67%) than without endothelium (49.44%). Chemical analysis of the extract showed the presence of alkaloids and ﬂavonoids which may be responsible for the antihypertensive properties. Copyright © 2004 John Wiley & Sons, Ltd.
Antiproliferative activity of Copaifera duckei oleoresin on liver regeneration in rats
Authors: Castro‐e‐Silva Orlando , Zucoloto Sérgio , Ramalho Fernando S. , Ramalho Leandra N. Z. , Reis José M. C. , Bastos Álvaro A. C. , Brito Marcus V. H. 
Published: January 2004

AbstractCopaiba oleoresin is widely used in folk medicine as an antiinﬂammatory, healing and antiseptic agent. Wistar rats received Copaifera duckei oleoresin (CDO) or saline solution (SS) from 7 days before surgery until killing. Partial hepatectomy (PH) or sham‐operation was performed. Hepatocellular proliferation and liver mitochondrial respiration were evaluated 24 h after the procedure. The proliferating cell nuclear antigen labelling index was signiﬁcantly lower in CDO‐treated plus PH rats than in SS‐treated plus PH rats, suggesting that CDO inhibited cell proliferation. The state 3 and state 4 respiration rates were greater for CDO‐treated groups, and the stimulation of state 4 respiration was more expressive. These data resulted in a signiﬁcant decrease in the respiratory control ratio observed for CDO‐treated groups, demonstrating the ability of CDO to uncouple oxidative phosphorylation in mitochondria, a fact that may be one explanation for the inhibition of hepatocellular proliferation observed in the CDO‐treated plus PH group. Copyright © 2004 John Wiley & Sons, Ltd.
Reproduction in male rats is vulnerable to treatment with the flavonoid‐rich seed extracts of Vitex negundo
Authors: Das Suwagmani , Parveen Seema , Kundra Chander Parkash , Pereira Ben M. J. 
Published: January 2004

AbstractA partially puriﬁed ﬂavonoid‐rich extract was prepared from the seed of Vitex negundo. The effect of this extract on the reproductive system of male rats was investigated at four different concentrations. All the major accessory sex organs shed weight when the preparation was administered at doses of ≥15 mg/rat/day after 15 days of treatment. The drop in weight was also reﬂected in disturbed tissue biochemistry. Secretory products such as citric acid in the prostate, fructose in seminal vesicles and epididymal α‐glucosidase activity, indices of accessory sex organ function in males, diminished. Microscopic examination of the sperm derived from the cauda epididymides of treated animals showed only a marginal change in vitality. However, sperm numbers dwindled and slackness in their motility was observed, factors that may impede fertility. Toxicity testing in blood did not point to distress in any of the vital organs. Taken together, it is inferred that the seed extracts of V. negundo interfere with male reproductive function without producing adverse toxicity in other vital organs. Copyright © 2004 John Wiley & Sons, Ltd.
Chemical analysis and antifungal activity of Thymus striatus
Authors: Couladis M. , Tzakou O. , Kujundzic S. , Sokovic M. , Mimica‐Dukic N. 
Published: January 2004

AbstractThe essential oil composition from Thymus striatus collected from Mountain Orjen (Montenegro) has been investigated by gas chromatography‐mass spectrometry. Thymol, γ‐terpinene and p‐cymene were found to be the major components. Furthermore, the oil and its major component, thymol, were analysed for potential antifungal activity against plant, animal and human pathogenic fungi from different genera by a macrodilution test. The oil exhibited a strong inhibitory effect against all fungi investigated. Copyright © 2004 John Wiley & Sons, Ltd.
Methanol extract of the oyster mushroom, Pleurotus florida, inhibits inﬂammation and platelet aggregation
Authors: Jose Nayana , Ajith T. A. , Janardhanan K. K. 
Published: January 2004

AbstractThe antiinﬂammatory and platelet aggregation inhibiting activities of the methanol extract of Pleurotus florida Eger, an edible and commercially grown mushroom, were investigated. The extract showed signiﬁcant activity in ameliorating acute inﬂammation induced by carrageenan and chronic inﬂammation by formalin at 500 and 1000 mg/kg body weight. The effect was comparable to the standard reference drug, diclofenac. The extract also showed signiﬁcant platelet aggregation inhibiting activity of washed human platelets. Adenosine 5′‐diphosphate (ADP) induced platelet aggregation was inhibited by 88% to 95% at a concentration of 500 µg/mL of the extract after a preincubation time of 5, 10 and 20 min. The marked antiinﬂammatory and platelet aggregation inhibiting properties of this mushroom suggest its potential therapeutic use against vascular disorders. Copyright © 2004 John Wiley & Sons, Ltd.