bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Layered Silicate on the Self‐Crosslinking of Polychloroprene and Carboxylated Nitrile Rubber
Authors: Das Amit , Stöckelhuber Klaus Werner , Heinrich Gert 
Published: December 2008

AbstractThe effect of organically modified clay on the properties of self‐crosslinkable carboxylated acrylonitrile‐butadiene rubber (XNBR) and polychloroprene rubber (CR) blend is studied. Results of blends produced without crosslinking agents are compared with conventional sulphur cured compounds. Sulphur cured blends exhibit improved physical properties after the incorporation of organophilic‐modified clay. In contrast, the self‐crosslinked blends do not show any reinforcement after the incorporation of the organoclay. XRD spectra show an intercalation of polymer chain into the gallery gap of the clay in both cases. ATR‐IR, DMA and SEM studies of these composites confirm that organoclay particles constrain the self‐crosslinking mechanism. The influence of the organoclay on the crystallisation of CR is also shown.magnified image
Concentration Effect on Temperature Dependence of Gelation Rate in Aqueous Solutions of Methylcellulose
Authors: Chen Kai , Baker Ashley N. , Vyazovkin Sergey 
Published: December 2008

AbstractThe gelation kinetics in methylcellulose solutions of different concentrations is studied by DSC under rising temperature conditions. Isoconversional analysis reveals that the rate is a complex function of temperature represented by a concave downward dependence of the effective activation energy on temperature (E vs. T). Although the initial decreasing portion of the dependence is consistent with the Fisher–Turnbull nucleation model, a description of the final increasing part requires introducing activation energy of diffusion that varies with conversion according to a power law. Parameters of the modified model evaluated from the E versus T dependencies suggest that the diffusion contribution increases with increase in the concentration, whereas the free energy barrier to nucleation remains almost unaffected.magnified image
Proteomics of brain extracellular fluid (ECF) and cerebrospinal fluid (CSF)
Authors: Maurer Martin H. 
Published: December 2008

AbstractMass spectrometry has become the gold standard for the identification of proteins in proteomics. In this review, I will discuss the available literature on proteomic experiments that analyze human cerebrospinal fluid (CSF) and brain extracellular fluid (ECF), mostly obtained by cerebral microdialysis. Both materials are of high diagnostic value in clinical neurology, for example, in cerebrovascular disorders like stroke, neurodegenerative diseases like Alzheimer's Disease, Parkinson's Disease, amyotrophic lateral sclerosis (ALS), traumatic brain injury and cerebral infectious and inflammatory disease, such as multiple sclerosis. Moreover, there are standard procedures for sampling. In a number of studies in recent years, biomarkers have been proposed in CSF and ECF for improved diagnosis or to control therapy, based on proteomics and mass spectrometry. I will also discuss the needs for a transition of research‐based experimental screening with mass spectrometry to fast and reliable diagnostic instrumentation for clinical use. © 2008 Wiley Periodicals, Inc., Mass Spec Rev 29:17–28, 2010
Statistical Distribution Analysis of Polypentenamer cis–trans Structural Units
Authors: Ismail Fadhel , Bendebane Farida , Bouziane Lamia , Boukhari Abbés 
Published: December 2008

AbstractSummary: The polypentenamer studied in this work, was a product obtained from bulk polymerization of gaseous cyclopentene into condensed polymer in presence of tungsten hexachloride alone as catalyst without any other reagent. This linear polymer doesn't present cross‐links or detectable secondary ramifications. However, its structural unit presents a double bond which can be in different configurations corresponding to cis and trans geometric isomers. The objective of this study was to determine the distribution type of these different structural units constituting the polymer chains. Fractions of cis and trans structural units in polymer chains were calculated from 13CNMR spectra. Statistical distribution of these structural units was observed on high resolution 13CNMR spectra, with the apparition of a quadruplet and a triplet corresponding respectively to the carbon on α and β position. The sextuplet corresponding to the carbon of the double bond was observed clearly in this work (may be because the product polymer is very pure), and confirms the statistical distribution. All peaks corresponding to the different positions of the α‐carbon, the β‐carbon and the olefinic carbon in polymer chains were attributed from statistical analysis of the polypentenamer microstructure.
Formulation of an Environmentally Friendly Adhesive for Wood
Authors: Ibrahim M. N. Mohamad , Ghani A. Md. , Zakaria N. , Shuib S. , Sipaut C. S. 
Published: December 2008

AbstractSummary: Malaysia has over 4 million hectares of oil palm plantations that yield large amounts of empty fruit bunches (EFB) generated from palm oil milling operations. These forms of lignocellulosic residue pose an environmental hazard if their disposal is not managed in a systematic manner. One of the useful elements extracted from these EFBs is lignin. The general purpose of this study is to explore the potential uses of lignin extracted from soda black liquor (paper and pulping waste) derived from oil palm empty fruit bunches (EFB) in the formulation of a more environmentally friendly wood adhesive. In this work, the potential for replacing phenol with lignin in phenol formaldehyde resin formulation is examined. The quantity of phenol was reduced by synthesizing the resin at a lignin to phenol ratio of 1:1. The physical and chemical properties of lignin phenol formaldehyde resin (LPF) and commercial phenol formaldehyde resin (CPF) were then compared. The infrared spectrum revealed similarities in the functional groups of both LPF and CPF resins. Tensile strength comparisons between both resins revealed that the LPF resin had a higher bonding strength (11.60 MPa more in term of allowable maximum load). In addition, the kinematics viscosity test showed that the LPF resin had lower kinematic viscosity than the CPF resin after 21 days of storage. Finally, the scanning electron microscope images for both resins showed similarities in terms of penetration into wood vessels.
Comparison of Syndiotactic Polystyrene Morphology Obtained Via Heterogeneous and Homogeneous Polymerization with Metallocene Catalyst
Authors: Rahmani Sohrab , Mohammadi Reza , Entezami Ali Akbar 
Published: December 2008

AbstractSummary: Supported catalyst system for the slurry phase polymerization of styrene in toluene was prepared by the immobilization of 2‐methylindenyltrichlorotitanium(2‐MeIndTiCl3) on silica and activation of this catalyst was performed by methylaluminoxane(MAO) in polymerization media. Homogeneous polymerization of styrene with 2‐methylindenyltrichlorotitanium activated by MAO was performed in toluene. The morphology of obtained syndiotactic polystyrene (sPS) via heterogeneous and homhgeneous catalyst system was compared. Polymerization of styrene by homogeneous catalyst lead to formation of gel and resultant polymers presented a compact and dense texture while the global gelation do not occur with silica supported catalyst at different Ti/SiO2 mol ratios and sPS was obtained as separated particles. Unlike to the homogeneous catalyst, obtained polymers showed a porous texture. Highly porous texture of sPS was obtained with Ti/SiO2 = 0.5% mol ratio.
Synthesis and Characterization of Bagasse Poly(methyl methacrylate) Graft Copolymer
Authors: Sarvi I. , Pourjavadi A. , Aghaei M. A. Noei 
Published: December 2008

AbstractSummary: Graft copolymerization of methyl methacrylate (MMA) was carried out on bagasse fibers in an aqueous medium using ceric ammonium nitrate (CAN) as initiator under a neutral atmosphere. In order to obtain the optimum condition for graft copolymerization, the effects of initiator concentration, temperature, time of reaction, and monomer concentration were studied. The maximum grafting percent was found to be 122%. The bagasse grafted poly(methyl methacrylate) was characterized by FTIR and its thermal behavior was characterized by TGA.
Preparation of Polyethylene/Layered Silicate Nanocomposites Using In Situ Polymerization Approach
Authors: Ramazani S. A. Ahmad , Tavakolzadeh Fahimeh 
Published: December 2008

AbstractSummary: In this paper, preparation of polyethylene/clay nanocomposites (PECNC) by in situ Ziegler‐Natta catalyst polymerization was investigated. A Ziegler‐Natta catalyst was first supported on montmorillonite (MMT) type clay and subsequently used for polymerizing ethylene. Clay and clay supported catalyst were characterized by Fourier transmission infrared and ICP method. X‐ray diffraction (XRD) and transmission electron microscopy results show that silicate layers of the mineral clay in prepared nanocomposites were intercalated and exfoliated in the polymeric matrix. Differential scanning calorimetry results show that the prepared nanocomposites have higher crystallization temperature than pure polyethylene.
New Nanoindentation and Nanoscratching Parameters of Thermoplastics
Authors: Naimi‐Jamal M. R. , Kaupp G. 
Published: December 2008

AbstractSummary: The determination of hardness and modulus values from unloading curves in nanoindentations is particularly troublesome with thermoplastic polymers and the values can strongly depend on the maximal normal force. Quantitative analysis of the loading curves provides reliable nanoindentation coefficients k (µN nm−3/2) as the slopes of linear plots that reliably characterize the pristine polymers and are potent interpolation tools. Kinks in the linear plots (here not observed with isotactic polypropylene (PP‐it)) indicate plastic‐viscoelastic transformations and separate the characterization of the degraded polymer with the smaller nanoindentation coefficients from the pristine polymer. The quantitative analysis of the correct relation between lateral and normal force in nanoscratching reveals the coefficient K (µN−1/2) as a basic extrapolation tool with direct and quantitative access to scratch resistance as a measure for wear that replaces the unfounded and never constant so‐called “friction coefficient FL/FN”. The linear plots of the correct relation between lateral and normal force reveal the occurrence of plastic‐viscoelastic transformations most distinctly by a kink and two linear ranges.
Microwave Assisted Benign Method of Chelating Resin Synthesis Having Different Thermal and Ion Exchange Properties
Authors: Shah B. A. , Shah A. V. , Patel Nayan B. 
Published: December 2008

AbstractSummary: Microwave irradiation method was used for synthesis of chelating ion exchange resin derived fom Salicylicacid‐Formaldehyde‐Resorcinol (SFR‐M). The resin was characterized by Elemental analysis, FTIR, TGA and SEM. The Broido and Horowitz‐Metzger method were used to calculate the energy of activation (Ea) from TGA. The microwave assisted chelating resin has different thermal behaviour as compared to conventional resin (SFR‐C). The sorption capacities of microwave SFR resin for transition metal ions are higher than conventional SFR resin. The separation of binary mixtures [Cu (II) and Zn (II)] in brass and [Ni (II) and Cd (II)] were successfully carried out using Kd value.
Effect of pH on the Behavior of Hyaluronic Acid in Dilute and Semidilute Aqueous Solutions
Authors: Maleki Atoosa , Kjøniksen Anna‐Lena , Nyström Bo 
Published: December 2008

AbstractSummary: Viscosity, asymmetric flow field‐flow fractionation (AFFFF) methods, and dynamic light scattering (DLS) experiments were used to characterize the effect of pH on the behavior of dilute and semidilute aqueous buffered solutions of hyaluronic acid (HA). It is shown that degradation of HA occurs at pH < 4 and pH > 11, and in the domain 4 < pH < 11 virtually no disruption of the HA chains occurs. The pH‐induced scission of HA is attributed to the cleavage of glycosidic bonds. In dilute solutions, intramolecular rupture of HA chains occurs and in the semidilute concentration regime network‐fragmentation is observed at low and high pH values. The degree of degradation of HA is most marked at high pH. From the molecular weight and radius of gyration obtained from AFFFF at different pH values, it is clear that the degradation of HA starts at early times after preparation of the solution, and continues for a couple of days. The kinetics of degradation of HA is fastest at high pH.
Processing and Properties of Nanocomposite Filament Yarns with Various Filler Concentrations from Two Different Modification Methods
Authors: Dastjerdi Roya , Mojtahedi M. R. M. , Shoshtari A. M. 
Published: December 2008

AbstractIn this research, the possibility of producing and processing nanocomposite polypropylene filament yarns with permanent antimicrobial efficiency has been assessed by comparing two different methods. Therefore two approaches were used to mix various blending contents of antimicrobial agents based on silver/TiO2nano particles with PP: 1) mixing of PP powder and inorganic nanocomposite powder as an antibacterial agent with the appropriate concentration in a twin screw extruder, preparing modified granules and feeding them to the melt spinning machine, 2) producing masterbatch by a twin screw extruder and blending it with PP in the melt spinning process. In both methods, pure PP and all other combined samples had an acceptable spinnability at the spinning temperature of 240 °C and take‐up speed of 2000 m/min. After producing as‐spun filament yarns by a pilot plant melt spinning machine, samples were drawn, textured and finally weft knitted. Physical and structural properties of as‐spun and drawn yarns with constant and variable draw ratios were investigated and compared. Moreover, the DSC, SEM and FTIR techniques have been used for samples characterization. Finally antibacterial efficiency of knitted samples was evaluated. The experimental results indicated that the maximum crystallinity reduction of modified as‐spun yarns reached 5%. But by applying method 2 (masterbatch), crystallinity of modified as‐spun yarns remained unchanged compared to pure yarn. However, drawing procedure has compensated this difference. By applying the second method, the drawing generally improved the increase of tenacity and modulus of modified fibers, whereas in method 1 the opposite effect was noticed in the case of constant draw ratio. Although the biostatic efficiency of nanocomposite fibers was excellent in both methods, modified fabrics obtained from method 1 showed higher bioactivity.
Study on In‐Situ Compatibilization of the PP/PA6 Blends in Twin Screw Extruders
Authors: Barangi Leila , Taromi Faramarz Afshar , Nazockdast Hossein 
Published: December 2008

AbstractThe in‐situ compatibilization of PP/PA6 blend was studied in a twin screw extruder. The maleic anhydride (MA) content, peroxide concentration, shear rate and feeding order were among the variables investigated. Degree of grafting of samples collected prior to feeding of PA6 into the extruder was measured using titration combined with FTIR technique. From the SEM results it was found that the increasing of initial MA concentration led to larger PA particle size which could be related to secondary reactions between excess MA and PA. The melt linear viscoelastic measurements performed on the blend samples and the obtained relaxation time spectra showed shorter form relaxation time and interfacial relaxation time for one‐step compatibilized sample compared to the sample prepared by the two‐step method with the same degree of grafting. This was attributed to the stronger interfacial interaction of the one‐step compatibilized blend samples which could be resulted from greater efficiency of grafting and/or compatibilization. These results were supported by SEM results which showed smaller particle size for the one‐step compatibilized samples. It was demonstrated that melt linear viscoelastic measurement could provide a great insight into understanding the compatibilization process in twin screw extruder.
Thermodynamic Modeling of Polymer Solution Interface
Authors: Ghiass Majid , Rey Alejandro D. 
Published: December 2008

AbstractA new method is presented to characterize the interfacial concentration field and interfacial tension between equilibrium polymer solution phases, using readily accessible equilibrium concentration data. The new method is tested and validated using experimental data from different polystyrene solutions and it consists of i) calculation of a universal expression for the concentration gradient coefficient based on the Cahn‐Hilliard model and the Wolf interfacial tension master equation, and ii) development of a highly accurate algebraic function (Kappa distribution) that, for a given equilibrium polymer concentration set, yields the essentially exact interfacial profile predicted by the classical gradient theory for polymer solutions.magnified image
A novel Global Assessment Scale for Wilson's Disease (GAS for WD)
Authors: Aggarwal Annu , Aggarwal Nitin , Nagral Aabha , Jankharia Govindji , Bhatt Mohit 
Published: December 2008

AbstractWilson's disease (WD) is an inherited disorder of copper metabolism. Despite being treatable, patients with WD suffer severe disabilities due to delay in initiation and difficulty in monitoring treatment. We propose a two tier,Global Assessment Scale for Wilson's Disease(GAS for WD) that grades the multisystemic manifestations of the disease.Tier 1scores the global disability in four domains: Liver, Cognition and behavior, Motor, and Osseomuscular.Tier 2is multidimensional scale for a fine grained evaluation of the neurological dysfunction. We prospectively validated this scale in 30 patients with WD. Both tiers had a high inter‐rater reliability (Intraclass correlation coefficient ICC (A, 2) = 0.96–1.0). Tier 2 items were internally consistent (Cronbach's α = 0.89) and factorial analysis showed that 90.3% of the Tier 2 total score variance was determined by seven factors. Scores of both tiers were commensurate with the disease burden as assessed by standard disability scales (Child Pugh, UPDRS, SS3, and CGI) and satisfied criteria for validity. Longitudinal follow‐up over 1.5 years showed that the scale was sensitive to clinical change. This suggests that GAS for WD is a practical tool with potential applications in management of patients, and in testing and comparison of treatment regimens. © 2008 Movement Disorder Society
Cloning, characterization and expression of zvep, a novel vitelline envelope‐specific gene in the zebrafish ovary
Authors: Xu Yan , Lei Yong , Liu Qian , Liu Yao , Liu Shuo , Cheng Hanhua , Deng Fengjiao 
Published: December 2008

AbstractThe egg envelope is a specialized extracellular matrix that surrounds and protects the oocyte and plays significant roles in animal reproductive and developmental processes. Using the NCBI digital differential display program we identified an EST sequence (XM_001340234.1) acquired from zebrafish ovary cDNA libraries in GeneBank. The full‐length cDNA of this transcript was obtained by 3′and 5′ RACE and further confirmed by PCR and sequencing. The full‐length cDNA of the novel gene is 2,720 bp and encodes a protein of 761 amino acids. RT‐PCR and Western blot analysis showed its expression in ovary and brain but not in other tissues. In situ hybridization demonstrates that the mRNA is transcribed in ooplasm of stage I, II, and III oocytes. Interestingly, immunohistochemistry on zebrafish ovarian sections showed that protein expression in the vitelline envelope was located to two thin positive lines in the stage III oocytes. These ovarian expression patterns show that this is a new component of the vitelline envelope that is synthesized during early developing oocytes. This protein was named ZVEP (zebrafish vitelline envelope protein) and it did not have any homology with other known vitelline envelope genes. Thus, we found that zvep is a novel gene related to the vitelline envelope in zebrafish. Mol. Reprod. Dev. 76: 593–600, 2009. © 2008 Wiley‐Liss, Inc.
Mating modifies apoptosis pattern in epithelial cells of the rat uterus
Authors: Mendoza‐Rodríguez C. Adriana , Martínez Miguel A. , Vargas Omar , Nava Karina , Morimoto Sumiko , Espinosa Mirielle , Cerbón Marco 
Published: December 2008

AbstractEstrous cycle in mammals includes marked epithelial changes in reproductive tract, regulated by sex steroid hormones. In the present work we studied the activation of caspases and apoptotic pattern in uterine epithelial cells during proestrus and estrus, and the effect of mating in this process. In addition, we investigated the role of seminal vesicle secretions on apoptosis of uterine epithelia. Apoptotic index was evaluated by TUNEL assay, caspases‐8, ‐9, and ‐3 activation was detected by Western blot and active caspase‐3 expression was detected by immunohistochemistry. Our results show that mating during proestrus and estrus transition induced changes in the apoptotic pattern of uterine luminal epithelium during estrus, characterized by a delay in the onset of apoptosis as compared with that observed in nonmated rats. No differences in the apoptotic pattern in the glandular epithelium between mated and nonmated rats were observed. Seminal vesicle secretions inhibited luminal epithelium apoptosis, while no changes in glandular epithelium apoptosis were observed. We also demonstrate that activation of caspases‐8, ‐9, and ‐3 occurred in both mated and nonmated rats. Active caspase‐3 was detected in the luminal and glandular epithelium in both nonmated and mated rats. The overall results indicate that mating delays but does not prevent the cellular death of the rat uterine luminal epithelium and seminal vesicle secretions are involved in this delay. Finally, the activation of both the mitochondrial and the membrane receptor pathways of cell death are implicated in the molecular mechanism of uterine apoptosis. Mol. Reprod. Dev. 76: 564–572, 2009. © 2008 Wiley‐Liss, Inc.
Roles of protein kinase C isotypes during seawater‐versus cAMP‐induced oocyte maturation in a marine worm
Authors: Stricker Stephen A. 
Published: December 2008

AbstractBased on immunoblotting analyses using phospho‐specific antibodies, follicle‐free oocytes of the marine nemertean wormCerebratulussp. activate protein kinase C (PKC) when induced to mature by either seawater (SW) or cAMP‐elevating drugs. In SW‐stimulated oocytes, the onset of maturation (=germinal vesicle breakdown, “GVBD”) can be inhibited by broadly acting PKC antagonists such as bisindoylmaleimide (BIM)‐I or BIM‐IX. Conversely, co‐treatment with SW solutions of BIM‐I or BIM‐IX plus a cAMP elevator (forskolin, serotonin, or a phosphodiesterase inhibitor) restores GVBD, indicating that the blockage of SW‐induced GVBD by PKC antagonists is not simply due to oocyte morbidity and that such inhibition is somehow reversible by cAMP signaling. In tests to determine which specific PKC may be involved in regulating GVBD, immunoblots fail to provide strong evidence for the presence of conventional or novel PKCs, which are characteristically activated by 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA). Moreover, inhibitors of TPA‐sensitive PKCs do not prevent SW‐induced GVBD, and TPA itself serves to downregulate, rather than stimulate, GVBD. Alternatively, maturing oocytes apparently possess phosphorylated forms of TPA‐insensitive isotypes, including an ∼67‐kDa atypical PKC and an ∼130‐kDa PKC‐related kinase (PRK). Accordingly, inhibitors of atypical PKC signaling block SW‐but not cAMP‐induced GVBD, collectively suggesting that instead of depending on a conventional or novel isotype, SW‐induced GVBD may require atypical PKC and/or PRK. In addition, such findings provide further support for the view that GVBD in nemertean oocytes can be achieved via multiple mechanisms, with SW triggering different signaling pathways than are stimulated in the presence of cAMP‐elevating drugs. Mol. Reprod. Dev. 76: 693–707, 2009. © 2008 Wiley‐Liss, Inc.