bluuebunny/crossref_metadata_2025_split huggingface dataset:
Toosendanin facilitates [3H]noradrenaline release from rat hippocampal slices
Authors: Hua‐Yu Huang , Cheng‐Wen Zhou , Yu‐Liang Shi 
Published: June 2010

AbstractSlices of hippocampus of the rat, preincubated with [3H]noradrenaline ([3H]NA), were used to investigate the effects of toosendanin on the release of [3H]NA. Toosendanin potently enhanced spontaneous 3H outflow. Seventy‐four percent of the enhancement was inhibited by reserpine pretreatment. The toosendanin‐induced 3H overflow was in a concentration‐dependent manner (5–60 μM) both in the presence and absence of extracellular calcium. Under Ca2+‐free conditions, the effect of toosendanin on 3H outflow was unchanged by TTX, but inhibited by Ca2+‐chelator BAPTA‐AM; dantrolene sodium failed to affect the toosendanin‐induced 3H outflow, while 3,4‐diaminopyridine showed an additive effect on the outflow with this substance. The findings suggest that in the absence of extracellular Ca2+, toosendanin enhances [3H]NA release through the liberation of intracellular Ca2+ stores.
Partial purification and characterization of an esterase from fusarium sporotrichioides
Authors: Park Joung J. , Chu Fun S. 
Published: June 2010

AbstractKinetics analysis of the growth of Fusarium sporotrichioides T‐424 at 15°C and 25°C in liquid culture for 35 days revealed that production of deacetylated trichothecenes was associated with an increased activity in fungal esterases High temperature (25°C) favored enzyme production and enhanced esterase activity. Electrophoresis of crude extracts from the mycelia of F. sporotrichioides T‐424 with carboxylesterase staining revealed that several esterases were produced by the fungus. Four carboxylesterase isoenzymes (I‐IV) were separated on a DEAE‐Sephadex anion exchange column. Type (III) esterase, having activities with the substrate 4‐nitrophenylacetate and acetanilide, as well as hydrolytic activity for T‐2 toxin and acetyl‐T‐2 toxin, was partially purified with ammonium sulfate precipitation, immunoaffinity column chromatography, and DEAE‐Sephadex A‐50 chromatography. The esterase (III) had a molecular weight around 68 kDa in SDS‐PAGE. For the deacylation of T‐2 toxin and acetyl‐T‐2 toxin, type (III) esterase had a high specificity for the acetyl group at the C‐3 and C‐4 positions The Km values for acetyl‐T‐2 and T‐2 toxin were found to be 41.35 μM and 0.38 μM, respectively. The Km value for the acetyl group at C‐3 is 110 times greater than for that at C‐4
Effects of ochratoxin A on the rat immune system after perinatal exposure
Authors: Thuvander Ann , Funseth Eva , Breitholtz‐Emanuelsson Anna , Hallén Ira Palminger , Oskarsson A. 
Published: June 2010

AbstractEffects on the immune system after perinatal exposure to ochratoxin A (OA) were studied in Sprague‐Dawley rats after single or repeated exposure of the dams. In a short‐term study, dams with litters were given a single dose of OA (0, 10, 50 or 250 μg/kg body weight) on day 11 of lactation. The effects on cell numbers in spleen and thymus and on the mitogen responses of lymphocytes were evaluated in the suckling pups on day 14 of lactation. The proliferative response of splenocytes to the T‐cell mitogen Concanavalin A (Con A) was significantly stimulated in pups from dams given 10 or 50 μg OA/kg body weight as compared to control pups. In addition, proliferation of thymocytes in response to Con A was stimulated in pups from dams exposed to 50 μg OA/kg body weight.In a long‐term, cross‐fostering study comparing pre‐ and postnatal exposure, half of the dams received 50 μg OA/kg body weight 5 days a week by gastric intubation 2 weeks before mating, during gestation and then 7 days a week until weaning. Effects on immune parameters were studied in the pups on day 14 of lactation and at 13 weeks of age. Suppressed mitogenic responses were seen to both lipopolysaccharide (LPS) and Con A in prenatally exposed pups sampled on day 14 of lactation. At 13 weeks the response of splenocytes to LPS was still impaired. The primary antibody response to a viral antigen was also lower in the prenatally exposed pups than in the control pups. These effects on the immune response were not seen in the groups of pups exposed postnatally or both pre‐ and postnatally, although blood concentrations of OA were higher in these groups at the time of the first sampling. This indicates that the decrease in proliferation and antibody production resulted from prenatal modulation of the immune system.The results show that prenatal exposure to relatively low doses of OA may induce immunosuppression. In contrast, short‐term exposure of suckling pups to OA via the milk stimulates the proliferative responses of lymphocytes to polyclonal activation.
Amino acid sequence of peptidyl‐prolyl isomerase a of fusarium sporotrichioides
Authors: Chow Lu‐Ping , Kamo Masaharu , Ueno Yoshio , Tsugita Akira 
Published: June 2010

AbstractPeptidyl‐prolyl‐cis‐trans isomerase catalyzes the interconversion of the cis and trans isomers of the proline‐containing polypeptides and the folding process of proteins. This protein was known to be cyclophilin which has high binding affinity for cyclosporin A, a cyclic undecapeptide of fungal origin with potent immunosuppressive property agent. The two cytosolic peptidyl‐prolyl‐isomerases were found from Fusarium sporotrichioides. The amino acid sequence of the major peptidyl‐prolyl isomerase a was determined by conventional sequencing methods; the protein with a calculated molecular mass of 19.7 kDa consisting of 179 amino acids. The comparison of the amino acid sequence of peptidyl‐prolyl‐isomerase from Fusarium with that of Nucerospora crassa revealed a significant degree of amino acid sequence homology (82.2%).
Influence of perinatal ochratoxin A exposure on the immune system in mice
Authors: Thuvander Ann , Dahl Petra , Breitholtz‐Emanuelsson Anna 
Published: June 2010

AbstractThe mycotoxin ochratoxin A (OA) is a well‐documented immunotoxic agent which affects both cellular and humoral immunity. In the present study, the effects of maternal exposure to single doses of OA during gestation or lactation were studied in Balb/c offspring. A single dose exposure of the dams to OA (500 μg/kg body weight) on day 16 of gestation resulted in decreased proliferation of splenic and thymic lymphocytes in response to mitogens in the pups at 15 days of age. Flow cytometry analysis of thymocyte subpopulations revealed lower percentages of mature CD4+cells and higher percentages of immature, double‐positive (CD4+CD8+) cells in the exposed pups. In contrast, a single exposure of the dams of OA on day 10 postpartum significantly increased the proliferative responsiveness of lymphocytes in the offspring when stimulated with B or T cell mitogens 3 days after the exposure. This effect was most prominent in the highest dose group (500 μg/kg body weight). The present results are in accordance with previous observations in rats, and show that the time of exposure significantly influences the immunotoxic effects of OA on the developing immune system in rodents.
Apoptotic cellular damage in mice after T‐2 toxin‐induced acute toxicosis
Authors: Ihara Tomomi , Sugamata Masao , Sekijima Masaru , Okumura Hiroki , Yoshino Naoto , Ueno Yoshio 
Published: June 2010

AbstractBy histopathologic, electron microscopic, and immunochemical observation, the mechanism of cellular death was investigated in thymus, spleen, and liver of mice given intraperitoneally sublethal doses of T‐2 toxin, a trichothecene mycotoxin. In the thymus and spleen of mice given 5.0 mg/kg body weight of T‐2 toxin and killed 12 hours later, a massive cellular destruction characterized by chromatin condensation was evident, and electron microscopy analysis revealed the presence of apoptotic bodies. In the liver of mice given 2.5 mg/kg of T‐2 toxin and killed 2 hours later, the induction of apoptotic cellular lesions was observed by electron microscopy, and Kupffer cells phagocytosed the apoptotic bodies. Such lesions were not observed in the mice killed 12 hours after receiving the toxin. In situ nick translation analysis (Tunel method) revealed DNA fragmentation in thymus, spleen, and liver shortly after administration of T‐2 toxin. As previously observed in vitro, these findings indicated that T‐2 toxin is a potent inducer of apoptotic cell death in thymus, spleen, and liver in vivo; especially in liver, apoptosis is induced rapidly as compared with the other tissues observed, and Kupffer cells play an important role for clearance of apoptosis. Nat. Toxins 5:141–145, 1997. © 1997 Wiley‐Liss, Inc.
Fabrication and Microstructure of C/Cu Composites
Authors: Liu Yiwen , Zhang Chengyu , Qiao Shengru , Yang Zhimao 
Published: June 2010

AbstractC/Cu composites were prepared by a melting infiltration technique in vacuum. In order to improve the wettability between Cu and carbon fibers, Ti (8 wt.‐%) and Cr (1 wt.‐%) were added to the Cu alloy. Microstructures of the composites and interface between C and Cu were investigated by XRD, SEM, EDS and HRTEM. The results show that the Ti and Cr improved the wettability between Cu and CC preform and the infiltration ability of Cu into CC preform greatly. The prepared C/Cu composites are characterized as having good interface bonding and high density. In the process of infiltration, Ti and Cr concentrate on the boundary of carbon fiber. Formation of TiC results from the reaction of Ti and C between Cu and carbon fiber.
Localization Events and Microstructural Evolution in Ultra‐Fine Grained NiTi Shape Memory Alloys during Thermo‐Mechanical Loading
Authors: Schaefer Andreas , Wagner Martin Franz‐Xaver , Pelegrina Jorge Luis , Olbricht Jürgen , Eggeler Gunther 
Published: June 2010

AbstractSubjecting a thin NiTi specimen to uniaxial tension often leads to a localized martensitic transformation: macroscopic transformation bands form and propagate through the specimen, separating it into regions of fully transformed martensite and original austenite. In the present study, the alternating current potential drop (ACPD) technique is used to analyze the change in electrical resistance of ultra‐fine grained NiTi wires subjected to a broad range of thermo‐mechanical load cases: (i) uniaxial tensile straining at constant temperatures (pseudoelastic deformation); (ii) cooling and heating through the transformation range at constant load (actuator load case); (iii) a combination of mechanical and thermal loading. We monitor the ACPD signals in several zones along the gauge length of specimens, and we demonstrate that a localized type of transformation is a generic feature of pseudoelastic as well as of shape memory deformation. Moreover, the ACPD signals allow to differentiate between temperature‐induced martensite (formed during cooling at no or relatively small loads), stress‐induced martensite, and reoriented martensite (formed under load at low temperatures).
Preparation and Tribological Properties of MoS2 Nanosheets
Authors: Wu Zhuangzhi , Wang Dezhi , Wang Yi , Sun Aokui 
Published: June 2010

AbstractMoS2 nanosheets were successfully synthesized by a micro‐domain reaction method, employing a ball‐milled mixture of MoO3 and S as starting materials. The obtained MoS2 nanosheets are monodisperse, and the length and width are about 100 and 10 nm, respectively. Furthermore, the tribological performances of the as‐obtained MoS2 nanosheets were studied and possible optimized mechanisms were also proposed.
Ab‐initio‐Thermochemie fester Stoffe
Authors: Stoffel Ralf Peter , Wessel Claudia , Lumey Marck‐Willem , Dronskowski Richard 
Published: June 2010

AbstractIn diesem Aufsatz stellen wir einen auf elektronentheoretischen Rechnungen beruhenden Zugang zu einer quantenchemischen Thermochemie von Feststoffen vor. Zunächst gehen wir auf lokale und kollektive Atomauslenkungen ein und erläutern kurz den theoretischen Hintergrund. Die fundamentale Bedeutung der Phononen, ihre Dispersionsrelationen, ihre experimentelle Bestimmung und ihre Berechnung wird beleuchtet, gefolgt von der systematischen Konstruktion thermodynamischer Potentiale auf dieser Basis. Anschließend liefern wir eine Rechenanleitung sowie eine kritische Analyse der erzielbaren Genauigkeit und zeigen dann, wie verschiedene festkörperchemische Probleme so angegangen werden können. Dazu gehört die Berechnung atomarer Aktivierungsenergien in perowskitischen Oxiden, aber auch die Berücksichtigung berechenbarer Schwingungsfrequenzen zur Aufklärung von Kristallstrukturen. Dann behandeln wir die klassisch oft beschriebene Druck‐ und Temperaturpolymorphie von elementarem Zinn und nehmen eine energetische Klassifikation metastabiler Oxidnitride des Tantals vor. Schließlich weisen wir für Hochtemperatursupraleiter nach, wie die Rechnungen zur Evaluation unbefriedigend präziser thermochemischer Daten herangezogen werden können. Am Ende zeigen wir die momentanen Grenzen und die zukünftigen Herausforderungen der Theorie auf.
Microdroplets in Microfluidics: An Evolving Platform for Discoveries in Chemistry and Biology
Authors: Theberge Ashleigh B. , Courtois Fabienne , Schaerli Yolanda , Fischlechner Martin , Abell Chris , Hollfelder Florian , Huck Wilhelm T. S. 
Published: June 2010

AbstractMicrodroplets in microfluidics offer a great number of opportunities in chemical and biological research. They provide a compartment in which species or reactions can be isolated, they are monodisperse and therefore suitable for quantitative studies, they offer the possibility to work with extremely small volumes, single cells, or single molecules, and are suitable for high‐throughput experiments. The aim of this Review is to show the importance of these features in enabling new experiments in biology and chemistry. The recent advances in device fabrication are highlighted as are the remaining technological challenges. Examples are presented to show how compartmentalization, monodispersity, single‐molecule sensitivity, and high throughput have been exploited in experiments that would have been extremely difficult outside the microfluidics platform.
Homogeneous Gold Catalysis Beyond Assumptions and Proposals—Characterized Intermediates
Authors: Hashmi A. Stephen K. 
Published: June 2010

AbstractGold catalysis is a very active area in the field of catalysis research. New reactions are published every week, amazing changes in the connectivity are often observed, the number of applications in total synthesis is increasing …︁—but what are the mechanisms of these reactions? Sound information can be provided by knowledge about the intermediates of these reactions.
Mechanical behavior of carbon nanofibre‐reinforced epoxy composites
Authors: Rana Sohel , Alagirusamy R. , Joshi Mangala 
Published: June 2010

AbstractEpoxy resins are widely used in a variety of applications because of their high chemical and corrosion resistance and good mechanical properties. But few types of epoxy resins are brittle and possess low toughness which makes them unsuitable for several structural applications. In this work, carbon nanofibres have been dispersed uniformly into the epoxy resin at a very low concentration (0.07 vol. %). Improvement of 98% in Young modulus, 24% in breaking stress and 144% in work of rupture was achieved in the best sample. The emphasis is on achieving uniform dispersion of carbon nanofibers into epoxy resin using a combination of techniques such as ultrasonication, use of solvent and surfactants. The fracture surfaces of the specimens were studied under scanning electron microscope to see the fracture mechanism of nanocomposites under tensile load and correlate it to the enhancement in their properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and characterization of degradable triarm low unsaturated poly(propylene oxide)‐block‐polylactide copolymers
Authors: Yang Dongmei , Lu Qi , Fan Zhongyong , Li Suming , Tu Jianjun , Wang Wei 
Published: June 2010

AbstractA series of novel degradable triarm poly(propylene oxide)‐block‐polylactide (PPO‐b‐PLA) copolymers was synthesized by ring‐opening polymerization of L‐lactide (LLA) or D,L‐lactide (DLLA) using low unsaturated PPO triols as macromolecular initiator. The chemical structures of the resulting copolymers were characterized by Fourier transform infrared (FTIR), gel permeation chromatography (GPC), and proton nuclear magnetic resonance (1H‐NMR) spectroscopy. Combination of FTIR, GPC, and NMR results confirmed the formation of PPO‐b‐PLA copolymers. One glass transition was observed by differential scanning calorimetry (DSC), suggesting good miscibility between PPO and PLA segments in the copolymers. DSC and wide‐angle X‐ray diffraction demonstrated that PPO‐b‐PLLA copolymers were semicrystalline materials, and the crystallinity increased with increasing the PLLA content. In contrast, PPO‐b‐PDLLA copolymers were totally amorphous. The PPO‐b‐PLA copolymers exhibited improved thermal stability when compared with PPO polyols according to thermogravimetric analysis. The thermal degradation behavior of the copolymers depended on the composition. Polyurethane foams were prepared by crosslinking PPO and PPO‐b‐PLA copolymers using isocyanate. Alkaline degradation of the foams was investigated in 10 wt/vol % NaOH at 80°C. The results show that the novel PPO‐b‐PLA copolymers could be promising as degradable polymeric materials. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Mechanical properties and thermal aging behavior of styrene‐butadiene rubbers vulcanized using liquid diene polymers as the plasticizer
Authors: Nakazono Takeo , Matsumoto Akikazu 
Published: June 2010

AbstractThe mechanical properties of styrene‐butadiene rubber (SBR) vulcanizates prepared using various plasticizers including liquid polybutadiene and styrene‐butadiene copolymers were investigated. The effect of the liquid polymers as the plasticizers on the mechanical properties of the polymers, such as the hardness, tensile storage modulus, tanδ, and the modulus at 100% elongation values, were determined before and after the thermal aging. As a result, it was revealed that the use of these liquid polymers gave less amount of change in the measurement values for the mechanical properties during the aging. The crosslinking density and the amount of free polymers were also determined on the basis of the swelling and extraction data, respectively, using several organic solvents. These results support the fact that the added liquid polymers are fixed to the SBR networks. We revealed the superiority of the liquid styrene‐butadiene copolymers as the plasticizer, which provides sufficient mechanical properties after vulcanization and the excellent maintenance of the properties during the thermal aging process. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of polyaniline surface modification of carbon nanofibers on cure kinetics of epoxy resin
Authors: Cai Zhi‐Qi , Movva Siva , Chiou Nan‐Rong , Guerra Dante , Hioe Yunior , Castro Jose M. , Lee L. James 
Published: June 2010

AbstractPolyaniline (PANI) “nanograss” was grown on carbon nanofibers (CNFs). The cure behavior of an epoxy resin with and without unmodified CNFs or PANI modified CNFs was studied by means of non‐isothermal and isothermal differential scanning calorimetry (DSC). CNFs accelerated the reaction of epoxy and diamine. PANI surface modification further increased the reaction rate and the extent of reaction. An autocatalytic cure kinetic model was used to fit the reaction curves. It was found that activation energies of the epoxy reaction decreased in the presence of CNFs and PANI modified CNFs. The observed catalytic effect of CNF and PANI surface coating can be very useful for low temperature cure of large epoxy composite products. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Latex dispersability index
Authors: Khorassani Manouchehr , Afshar‐Taromi Faramarz , Pourmahdian Saeed 
Published: June 2010

AbstractThe pigment loading capacity (PLC) of dispersion binders is an important factor in the formulation of a latex paint. However, there has been no reliable method for the quantitative evaluation of this property; this has led to difficulty in comparing latex binders in this regard. In this article, a new parameter, the latex dispersability index (LDI), is proposed as a quantitative measure of PLC of latex binders. In this test method, the capability of latex to disperse pigments (or extenders) is quantified on the basis of the idea of the minimum viscosity method for dispersants. The face‐centered cube experimental design was used to synthesize 26 binders. On the basis of this design, the synthesized latexes had a maximum diversity of properties, especially with regard to PLC. The binders were formulated with three mineral powders (i.e., TiO2, CaCO3, and talc). The curves of viscosity versus mass of the resin for all of the samples were prepared. The general trend of the curves was universal and only depended on the nature of the powders. The geometry of the curves and PLC had quantitative correlations. To make a quantitative correlation between the curves and PLC, LDI was defined as a function of the area under the curve, the height of the curve, and the length of the end point. Four ranges of LDI were assigned to the conventional quantitative phrases for PLC. The usefulness of this parameter was then verified by some well‐known commercial binders with different PLCs. The results were in a good agreement with the expected behaviors. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Rheological studies on energetic thermoplastic elastomers
Authors: Reddy T. S. , Nair J. K. , Satpute R. S. , Gore G. M. , Sikder A. K. 
Published: June 2010

AbstractEnergetic thermoplastic elastomers containing energetic groups, such as azido, nitrato, nitro, and so forth, are emerging as attractive binder systems for advanced solid rocket propellants. Poly[3,3‐bis(Azidomethyl) oxetane (BAMO)‐co‐3‐azidomethyl‐3‐methyl oxetane (AMMO)] comprising hard crystalline BAMO segment and the soft/amorphous AMMO segment in various molar ratios (80 : 20, 50 : 50 and 20 : 80) were synthesized during the present work. The homo polymers namely Poly‐BAMO and Poly‐AMMO were also synthesized. All the polymers and copolymers were characterized by spectral and thermal methods. They were found to be thermally stable. The most promising 80 : 20 copolymer softened at 56°C with Tg of −36°C. Rheological studies were also carried out to determine their suitability as a binder in explosive and propellant formulations. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Antibacterial polyvinyl chloride/antibiotic films: The effect of solvent on morphology, antibacterial activity, and release kinetics
Authors: Merchan Martha , Sedlarikova Jana , Sedlarik Vladimir , Machovsky Michal , Svobodova Jitka , Saha Petr 
Published: June 2010

AbstractMedical‐grade polyvinyl chloride was modified with sodium ampicillin in a concentration range from 0 to 5 wt % by solvent casting technique using cyclohexanone and N,N‐dimethylformamide. The obtained polymeric systems were characterized by optical microscopy, tensile test, and scanning electron microscopy. In addition, in vitro antibacterial activity against Gram‐negative and Gram‐positive bacteria was determined by an agar diffusion test. Antibiotic release experiments were performed in distilled water and physiological saline solution, which were monitored by UV‐vis spectroscopy. The results showed a crucial role of the solvent on the morphology, antibacterial activity, and releasing characteristic of the ampicillin. Furthermore, a mathematical model was applied to data obtained from release study, to characterize the release kinetics of the ampicillin from the polyvinyl chloride‐antibiotic systems. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010