bluuebunny/crossref_metadata_2025_split huggingface dataset:
PI3 kinase/Akt activation mediates estrogen and IGF‐1 nigral DA neuronal neuroprotection against a unilateral rat model of Parkinson's disease
Authors: Quesada Arnulfo , Lee Becky Y. , Micevych Paul E. 
Published: February 2008

AbstractRecently, using the medial forebrain bundle (MFB) 6‐hydroxydopmaine (6‐OHDA) lesion rat model of Parkinson's disease (PD), we have demonstrated that blockade of central IGF‐1 receptors (IGF‐1R) attenuated estrogen neuroprotection of substantia nigra pars compacta (SNpc) DA neurons, but exacerbated 6‐OHDA lesions in IGF‐1 only treated rats (Quesada and Micevych [2004]: J Neurosci Res 75:107–116). This suggested that the IGF‐1 system is a central mechanism through which estrogen acts to protect the nigrostriatal DA system. Moreover, these results also suggest that IGF‐1R‐induced intracellular signaling pathways are involved in the estrogen mechanism that promotes neuronal survival.In vitro, two convergent intracellular signaling pathways used by estrogen and IGF‐1, the mitogen‐activated protein kinase (MAPK/ERK), and phosphatidyl‐inositol‐3‐kinase/Akt (PI3K/Akt), have been demonstrated to be neuroprotective. Continuous central infusions of MAPK/ERK and PI3K/Akt inhibitors were used to test the hypothesis that one or both of these signal transduction pathways mediates estrogen and/or IGF‐1 neuroprotection of SNpc DA neurons after a unilateral administration of 6‐OHDA into the MFB of rats. Motor behavior tests and tyrosine hydroxylase immunoreactivity revealed that the inhibitor of the PI3K/Akt pathway (LY294002) blocked the survival effects of both estrogen and IGF‐1, while an inhibitor of the MAPK/ERK signaling (PD98059) was ineffective. Western blot analyses showed that estrogen and IGF‐1 treatments increased PI3K/Akt activation in the SN; however, MAPK/ERK activation was decreased in the SN. Indeed, continuous infusions of inhibitors blocked phosphorylation of PI3K/Akt and MAPK/ERK. These findings indicate that estrogen and IGF‐1‐mediated SNpc DA neuronal protection is dependent on PI3K/Akt signaling, but not on the MAPK/ERK pathway. © 2008 Wiley Periodicals, Inc. Develop Neurobiol 2008
Recoverable Phase‐Transfer Catalysts with Fluorinated Anions: Generation and Reactions of Dichlorocarbene and CCl3 Anion in the Heterogeneous System KOH(s)/CHCl3/nBu4NPF6
Authors: Kryshtal Galina V. , Zhdankina Galina M. , Zlotin Sergei G. 
Published: February 2008

AbstractTetraalkylammonium salts bearing PF6– and BF4– anions have been recognized as recoverable phase‐transfer catalysts for the synthesis of 1,1‐dichlorocyclopropane and α‐(trichloromethyl)carbinol derivatives from alkenes or aldehydes in the heterogeneous system KOH(s)/CHCl3. The catalysts retained their catalytic activity over several reactioncycles.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
The integrated water balance and water temperature model LARSIM‐WT
Authors: Haag I. , Luce A. 
Published: February 2008

AbstractThe goal of this article is to describe the integrated water balance and water temperature model LARSIM‐WT (large area runoff simulation model‐water‐temperature). The integrated model is an extension of the water balance model LARSIM, which simulates all major aspects of the terrestrial water cycle. The newly added water temperature module allows simulation and forecasting of river water temperatures (RWTs) throughout the complete river network using a deterministic approach, accounting for heat exchange processes along the flow path as well as local sources such as thermal discharges. In addition, it is also possible to calculate RWTs with regression models for specific locations in the river network. Applying LARSIM‐WT to the 14 000 km2 watershed of the Neckar River showed that the model is well‐suited to simulate RWTs along with discharges. Forecast tests proved the adequacy of the model for operational RWT forecasting for up to seven days ahead. The model has been continuously used for automated daily river temperature and discharge forecasting for the Neckar River since 2004. Moreover, it has also been successfully applied to predict the impact of climate change on water temperatures in the Neckar River. Copyright © 2008 John Wiley & Sons, Ltd.
Hen egg white lysozyme fibrillation: a deep‐UV resonance Raman spectroscopic study
Authors: Xu Ming , Ermolenkov Vladimir V. , Uversky Vladimir N. , Lednev Igor K. 
Published: February 2008

AbstractAmyloid fibrils are associated with numerous degenerative diseases. The molecular mechanism of the structural transformation of native protein to the highly ordered cross‐β structure, the key feature of amyloid fibrils, is under active investigation. Conventional biophysical methods have limited application in addressing the problem because of the heterogeneous nature of the system. In this study, we demonstrated that deep‐UV resonance Raman (DUVRR) spectroscopy in combination with circular dichroism (CD) and intrinsic tryptophan fluorescence allowed for quantitative characterization of protein structural evolution at all stages of hen egg white lysozyme fibrillation in vitro. DUVRR spectroscopy was found to be complimentary to the far‐UV CD because it is (i) more sensitive to β ‐sheet than to α ‐helix, and (ii) capable of characterizing quantitatively inhomogeneous and highly light‐scattering samples. In addition, phenylalanine, a natural DUVRR spectroscopic biomarker of protein structural rearrangements, exhibited substantial changes in the Raman cross section of the 1000‐cm–1 band at various stages of fibrillation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The source of lamellar mitochondria‐rich cells in the air‐breathing fish, Trichogaster leeri
Authors: Lee Wen , Huang Chun‐Yen , Lin Hui‐Chen 
Published: February 2008

AbstractPavement cells and the mitochondria‐rich cells (MRCs) are two of the main types of cells in fish gill epithelia. The pavement cells are generally responsible for gas exchange and MRCs for ion regulation. MRCs are found especially in the trailing edge and the interlamellar region of gill filament. In some species, MRCs are also observed in the gill lamellae. A previous study reported the likelihood of having lamellar MRCs in air‐breathing fishes. Nevertheless, the source of lamellar MRCs is unclear. We used the air‐breathing fish, Trichogaster leeri, to investigate the source of proliferated cells on the lamellae when 5‐bromo‐2‐deoxyuridine (BrdU) was injected at different times before fish were sampled from deionized water. There were two major findings in this study. First, undifferentiated cells were found in the lamellae, as well as in the filaments. And, within 12–24 hr, a proliferated cell, identified as BrdU cell, could differentiate to an MRC in the gill lamellae. Second, the filaments and the lamellae in T. leeri responded to ionic stress differently but the proportion of the proliferated MRCs to the BrdU cells remained constant. Our results suggested that the lamellar MRCs were mainly differentiated from the cells that proliferated earlier from the lamellae. J. Exp. Zool. 309A:198–205, 2008. © 2008 Wiley‐Liss, Inc.
Separation and determination of biogenic amines in fish using MEKC with novel multiphoton excitation fluorescence detection
Authors: Feng Xiaojun , Chen Sheng , Xu Youzhi , Du Wei , Luo Qingming , Liu Bi‐Feng 
Published: February 2008

AbstractBiogenic amines are a group of biological molecules derived from the enzymatic decarboxylation of natural amino acids. They can be found in a variety of foods and some of them are involved in essential cellular pathways regulating cellular functions. To address the issues raised by conventional detection methods for biogenic amines, such as laborious sample preparation and limited sensitivity, a new micellar electrokinetic chromatography scheme was developed based on multiphoton excitation fluorescence (MPEF) detection. Six FITC‐labeled biogenic amine species were used for the evaluation of this MEKC–MPEF method in comparison to single photon excitation fluorescence detection. The results indicated that MEKC–MPEF had superior resolution with a detection volume as low as aL. Quantitative analysis of varying concentrations of biogenic amine species has also been achieved suggesting a ymole mass detection limit, a linear dynamic range of about two orders of magnitude, and 95–105% recoveries. Furthermore, the biogenic amine profile of decayed oriental crucian carps was successfully determined and quantified using this new method.
Analytical results for 2‐D non‐rectilinear waveguides based on a Green's function
Authors: Ciraolo Giulio , Magnanini Rolando 
Published: February 2008

AbstractWe consider the problem of wave propagation for a 2‐D rectilinear optical waveguide which presents some perturbation. We construct a mathematical framework to study such a problem and prove the existence of a solution for the case of small imperfections. Our results are based on the knowledge of a Green's function for the rectilinear case. Copyright © 2008 John Wiley & Sons, Ltd.
Expression of FGF2 and TGFα and testis morphology during testicular hypertrophy subsequent to hemicastration in the neonatal boar
Authors: Wells R. , Scott P.T. , Harrison D.K. , Wreford N.G. , Duckett R. , Johnston S.D. , D'Occhio M.J. 
Published: February 2008

AbstractThe objective was to ascertain fibroblast growth factor‐2 (FGF2), epidermal growth factor (EGF), and transforming growth factor‐α (TGFα) mRNA expression and testis morphology during accelerated testicular growth after hemicastration in the neonatal boar. On Day 10 after birth (Day 0), boars were assigned to control (n = 28), no treatment; hemicastrated (n = 28), left testis removed. The right testis in both groups (n = 7) was removed on Days 5, 10, 15, and 20. Expression of mRNA for FGF2, EGF, and TGFα was determined by qRT‐PCR using TaqMan®. Testicular morphology was determined on Day 15. On Day 10, hemicastrated boars had a greater (P = 0.01) testis weight (6.2 ± 0.8 g; mean ± SEM) than controls (4.3 ± 0.4 g) and on Day 15 testis weight in hemicastrated boars (8.8 ± 0.8 g) was twice (P < 0.01) that of control boars (4.2 ± 0.3 g). Seminiferous tubule volume was approximately doubled in hemicastrated boars (P < 0.01) and was associated with an increase (P < 0.01) in Sertoli cell number. Interstitial compartment volume was greater (P < 0.01) in hemicastrated boars. Leydig cell numbers were similar (P = 0.14) but volume was greater (P < 0.01) for hemicastrates. There were no differences (P > 0.05) between control and hemicastrated boars in TGFα or FGF2 expression on Day 5 or Day 10, and EGF was not detected. It was concluded that upregulation of TGFα or FGF2 expression is not a pre‐requisite for enhanced testicular growth and increased Sertoli cell proliferation that occurs subsequent to hemicastration in the neonatal boar. Mol. Reprod. Dev. 75: 961–966, 2008. © 2008 Wiley‐Liss, Inc.
Modeling of resin infusion in vacuum assisted resin transfer molding
Authors: Song Young Seok , Youn Jae Ryoun 
Published: February 2008

AbstractResin infusion was modeled and analytic solutions were obtained for vacuum assisted resin transfer molding (VARTM). Compaction behavior of the fiber preform was examined experimentally and the influence of compressibility of the preform on the resin infusion was investigated mathematically. Flow front advancement through the preform was predicted by the analytic model proposed in the present study. The model provided pressure and thickness distributions of the region impregnated by the resin. For verification of the analytic solutions, a resin infusion experiment and a mold filling simulation for VARTM were performed and compared with the analytic ones. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers.
Impedance analysis and electromagnetic interference shielding effectiveness of conductive carbon black reinforced microcellular EPDM rubber vulcanizates
Authors: Mahapatra S.P. , Sridhar V. , Tripathy D.K. 
Published: February 2008

AbstractThe effect of processing variables (filler and blowing agent loadings) and operating variables (frequency and sample thickness) on the impedance and electromagnetic interference (EMI) shielding effectiveness of excess conductive carbon black reinforced solid and microcellular EPDM vulcanizates has been investigated. Increasing frequency showed a decrease in real part of complex impedance for both filler and blowing agent loadings, whereas the imaginary part showed a slight peak in the range of 9–10 GHz followed by a subsequent decrease. The measured impedance values were plotted as Nyquist plots (Argand diagrams) and a Resistor–Capacitance model was assumed. Increasing blowing agent loadings showed a marginal increase in the bulk resistivity, whereas increasing filler loadings had a significant decrease. The EMI shielding effectiveness increased monotonically with filler loading and showed a maximum of around 75 dB at 60 phr loadings, thus making them suitable for shielding applications. Increasing blowing agent loadings showed an increase in shielding effectiveness at low loadings (2 phr) whereas further increase showed a rapid decrease. This has been explained on the basis of formation of voids in the composite, which affect the absorbance capacity of the microcellular vulcanizates. However, the microcellular composites showed sufficiently high values in the range of 50–60 Db, thus making Vulcan XC 72 reinforced microcellular EPDM vulcanizates as ideal packaging material for EMI shielding applications. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Recycled poly(ethylene terephthalate) reinforced with basalt fibres: Rheology, structure, and utility properties
Authors: Kráčalík Milan , Pospíšil Ladislav , Šlouf Miroslav , Mikešová Jana , Sikora Antonín , Šimoník Josef , Fortelný Ivan 
Published: February 2008

AbstractUtilization of recycled poly(ethylene terephthalate) (PET) as a matrix for composite materials prepared by continuous compounding is challenging from the environmental as well as industrial point of view. In our work, cut basalt fibers and talc powder of various compositions were used and their reinforcing effect on recycled PET was tested by rheology (Advanced Rheometric Expansion System), differential scanning calorimetry, and tensile experiments. The quality of filler dispersion in recycled PET matrix was investigated by scanning electron microscopy (SEM) and melt rheology. Processing and utility properties of composites were enhanced as compared with those of unfilled matrix. Higher melt elasticity, interfacial adhesion, and better mechanical performance of the composites were in a good agreement with the structure observed from SEM micrographs. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Effect of matrix chemical structure on the thermo‐oxidative stability of addition cure poly(imide siloxane) composites
Authors: Lincoln Jason E. , Morgan Roger J. , Curliss David B. 
Published: February 2008

AbstractA series of addition cure poly(imide siloxane) resins were synthesized, incorporating various concentrations of α, ω‐bis(3‐aminopropyl) poly(dimethyl‐diphenylsiloxanes), and α, ω‐bis(p‐aminophenyl) poly(dimethylsiloxane) into the formulated imide oligomer. Both carbon and glass fiber textile laminates were fabricated using amic acid and polymerization of monomer reactants (PMR) approaches. The cured composite laminates were subjected to an accelerated thermo‐oxidative aging environment of 400°C for 100 h in air. Physical, thermal, and mechanical properties were evaluated to determine the structure‐oxidative stability interrelationships. In general, composite mechanical properties were found to increase with increasing siloxane concentration in the matrix. Composite thermo‐oxidative durability (measured via mass loss and mechanical property retention after oxidative aging) was improved through incorporation of diphenyl and diphenyl‐dimethyl siloxane segments into the imide oligomer backbone up to ∼35% by weight aminosiloxane. Oxidative stability was found to be mostly dependent on the degree of phenyl substitution on the silicon atoms in the siloxane blocks, as compared to the moiety attaching the amine groups to the siloxane block. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Effect of layered silicate on EPDM/EVA blend nanocomposite: Dynamic mechanical, thermal, and swelling properties
Authors: Acharya H. , Kuila T. , Srivastava S.K. , Bhowmick Anil. K. 
Published: February 2008

AbstractPolymer blend nanocomposites have been developed by solution method using ethylene propylene diene terpolymer (EPDM), ethylene vinyl acetate (EVA‐45) copolymer, and organically modified layered silicate. Morphological investigation made by wide‐angle X‐ray diffraction and transmission electron microscopic analysis indicates intercalated structure of EPDM/EVA nanocomposites with partial disorder. Scanning electron microscopic studies exhibit the phase behavior of EPDM/EVA blend nanocomposites. Dynamic mechanical thermal analysis shows a significant increase in storage modulus in the rubbery plateau. The decrease in damping (tan δ) value and enhanced glass‐transition temperature (Tg) demonstrate the reinforcing effect of layered silicate in the EPDM/EVA blend matrix. The tensile modulus of these nanocomposites also showed a significant improvement with the filler content. The main chain scission of EPDM/EVA blend nanocomposites compared with the neat EPDM/EVA blend showed substantial improvement in thermal stability in nitrogen, whereas a sizeable increase is observed in air. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Mechanical behavior of highly filled natural CaCO3 composites: Effect of particle size distribution and interface interactions
Authors: Kaully T. , Siegmann A. , Shacham D. 
Published: February 2008

AbstractThe mechanical behavior of poly(di‐methyl siloxane) (PDMS) composites containing high volume fractions of natural CaCO3 particles of various particle size distributions was studied under tensile and oscillatory bending stresses, emphasizing the unique behavior of high filler loaded compositions. Composites containing the maximal possible solid loading of raw CaCO3 were investigated for the effect of fatty acids surface treatment. The elastic modulus increased with increasing filler loading, following Chantler's model for dental composites when correlated with the absolute filler volume fraction. Good fit to “traditional” models, e.g., Frankle‐Acrivos and Halpin‐Tsai, was obtained by correlating the modulus values with the volume fraction relative to the maximal possible filler loading. A master curve of different particle size distributions and filler levels composites was obtained by using the relative volume fraction values, illustrating the effect of particle packing characteristics on small deformation mechanical behavior. A minor increase in Tg was found in parallel to the appearance of a Tm relaxation peak at approximately −40°C. A peak temperature shift at Tm and a pronounced increase in this peak with increasing filler fraction was found as well. The changes in the melting transition are attributed to the constraints of the filler particles acting on the crosslinked melting polymer. Surface treatment with fatty acids significantly degraded the tensile properties. Interestingly, an increase of 4 vol% filler was enabled owing to the surface treatment, while restoring reasonable tensile properties. No significant effect was observed for excess of fatty acids resulting from physically adsorbed acids. Tan δ curves reveal low PDMS‐CaCO3 particles interactions, and mobility of the PDMS chains in the increased filler fraction as in the treated 64 vol% composite, both higher than those in the raw composite. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Electrical and mechanical properties of multi‐walled carbon nanotubes reinforced PMMA and PS composites
Authors: Mathur R.B. , Pande Shailaja , Singh B.P. , Dhami T.L. 
Published: February 2008

AbstractThe use of multi‐walled carbon nanotubes (MWCNT) as reinforcing material for thermoplastic polymer matrices, polymethyl methacrylate (PMMA), and polystyrene (PS) has been studied. MWCNT were synthesized by chemical vapor deposition (CVD) technique using ferrocene‐toluene mixture. As‐prepared nanotubes were ultrasonically dispersed in toluene and subsequently dispersed in PMMA and PS. Thin polymer composite films were fabricated by solvent casting. The effect of nanotube content on the electrical and mechanical properties of the nanocomposites was investigated. An improvement in electrical conductivity from insulating to conducting with increasing MWCNT content was observed. The carbon nanotube network showed a classical percolating network behavior with a low percolation threshold. Electromagnetic interference (EMI) shielding effectiveness value of about 18 dB was obtained in the frequency range 8.0–12 GHz (X‐band), for a 10 vol% CNT loading. An improved composite fabrication process using casting followed by compression molding and use of functionalized MWCNT resulted in increased composites strength. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Development and high stress abrasive wear behavior of milled carbon fiber‐reinforced epoxy gradient composites
Authors: Chand Navin , Naik A.M. 
Published: February 2008

AbstractMilled carbon fiber‐reinforced polysulfide‐modified epoxy gradient composites have been developed. Density and hardness increases with the increase of carbon fiber content in the direction of centrifugal force, which shows the formation of gradient structure in the composite. High stress abrasive wear test was conducted on the gradient composites by using a Suga Abrasion Wear Tester. Abrasive wear rate reduced on increase of milled carbon fiber content from 0.15 to 1.66 vol%. Reduction in abrasive wear rate in milled carbon fiber‐reinforced epoxy gradient composites has been attributed to the increase of hardness, presence of random milled fibers, and debris of composite materials, which gave resistance and reduced wear rate. There is a small decrease in specific wear rate on adding 0.15 vol% milled carbon fibers. Further decrease of specific wear rate is observed on adding 0.45 vol% milled carbon fibers. After 3 N load, there is a decrease in specific wear rate behavior on adding 0.45 vol% carbon fibers, which further decreases on adding 0.60 vol% of carbon fibers. There is a remarkable decrease in specific wear rate up to 5 N load for 1.66 vol% milled carbon fiber‐reinforced composite. Reduction in specific wear rate on adding milled carbon fibers is based on the formation of debris, which remained intact in their respective positions due to the interfacial adhesion between milled carbon fibers and epoxy resin. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers