bluuebunny/crossref_metadata_2025_split huggingface dataset:
A gene expression phenotype in lymphocytes from friedreich ataxia patients
Authors: Coppola Giovanni , Burnett Ryan , Perlman Susan , Versano Revital , Gao Fuying , Plasterer Heather , Rai Myriam , Saccá Francesco , Filla Alessandro , Lynch David R. , Rusche James R. , Gottesfeld Joel M. , Pandolfo Massimo , Geschwind Daniel H. 
Published: June 2011

AbstractObjective:Gene expression studies in peripheral tissues from patients with neurodegenerative disorders can provide insights into disease pathogenesis, and identify potential biomarkers, an important goal of translational research in neurodegeneration. Friedreich Ataxia (FRDA) is a chronic neurodegenerative disease caused by reduced transcription of frataxin, a ubiquitously expressed protein. We studied in vitro lymphocytes from FRDA patients and carriers to identify a peripheral gene expression phenotype. Peripheral biomarkers related to disease status would be extremely valuable for assessing drug efficacy and could provide new pathophysiological insights.Methods:We characterized the gene expression profiles in peripheral blood mononuclear cells (PBMCs) from FRDA patients, compared with controls and related carriers. Cells were studied both before and after in vitro treatment with compounds that increase frataxin levels. Quantitative real‐time polymerase chain reaction and additional microarrays were used to confirm a core set of genes in multiple independent series.Results:We identified a subset of genes changed in cells from patients with pathological frataxin deficiency, and a core set of these genes were confirmed in independent series. Changes in gene expression were related to the mitochondria, lipid metabolism, cell cycle, and DNA repair, consistent with FRDA's known pathophysiology. We evaluated the in vitro effect of multiple compounds (histone deacetylase inhibitors) on this putative biomarker set, and found that this biochemical phenotype was ameliorated in accordance with drug efficacy.Interpretation:Frataxin downregulation is associated with robust changes in gene expression in PBMCs, providing pathogenetic insights and a core subset of genes that, if verified in vivo, could be used as a peripheral biomarker. ANN NEUROL 2011
Toll‐like receptor 4 contributes to poor outcome after intracerebral hemorrhage
Authors: Sansing Lauren H. , Harris Tajie H. , Welsh Frank A. , Kasner Scott E. , Hunter Christopher A. , Kariko Katalin 
Published: June 2011

AbstractObjective:Intracerebral hemorrhage (ICH) is a devastating stroke subtype in which perihematomal inflammation contributes to neuronal injury and functional disability. Histologically, the region becomes infiltrated with neutrophils and activated microglia followed by neuronal loss, but little is known about the immune signals that coordinate these events. This study aimed to determine the role of Toll‐like receptor 4 (TLR4) in the innate immune response after ICH and its impact on neurobehavioral outcome.Methods:Transgenic mice incapable of TLR4 signaling and wild‐type controls were subjected to striatal blood injection to model ICH. The perihematomal inflammatory response was then quantified by immunohistochemistry, whole brain flow cytometry, and polymerase chain reaction. The critical location of TLR4 signaling was determined by blood transfer experiments between genotypes. Functional outcomes were quantified in all cohorts using the cylinder and open field tests.Results:TLR4‐deficient mice had markedly decreased perihematomal inflammation, associated with reduced recruitment of neutrophils and monocytes, fewer microglia, and improved functional outcome by day 3 after ICH. Moreover, blood transfer experiments revealed that TLR4 on leukocytes or platelets within the hemorrhage contributes to perihematomal leukocyte infiltration and the neurological deficit.Interpretation:Together, these data identify a critical role for TLR4 signaling in perihematomal inflammation and injury and indicate this pathway may be a target for therapeutic intervention. ANN NEUROL 2011;70:646–656
Schleuservermittelter Transport von Wirkstoffen ins Gehirn
Authors: Malakoutikhah Morteza , Teixidó Meritxell , Giralt Ernest 
Published: June 2011

AbstractWährend des letzten Jahrzehnts wurden im Bereich der Wirkstofffreisetzung wesentliche Fortschritte erzielt. Die Behandlung von Gehirnerkrankungen bleibt aber wegen der Blut‐Hirn‐Schranke (BHS; blood–brain barrier) noch immer eine große Herausforderung. Diese Struktur schränkt den Zugang von Wirkstoffen zu ihrem Wirkort im Zentralnervensystem stark ein. Es wurden verschiedene Strategien vorgeschlagen, um den Transport von Wirkstoffen über die BHS zu verstärken. In diesem Aufsatz konzentrieren wir uns auf einen vektorvermittelten Ansatz, bei dem der Wirkstoff an ein Schleusermolekül gekuppelt wird, das die Fähigkeit hat, die BHS zu überqueren und die Substanz ins Gehirn abzugeben.
Multicomponent Reaction Design in the Quest for Molecular Complexity and Diversity
Authors: Ruijter Eelco , Scheffelaar Rachel , Orru Romano V. A. 
Published: June 2011

AbstractMulticomponent reactions have become increasingly popular as tools for the rapid generation of small‐molecule libraries. However, to ensure sufficient molecular diversity and complexity, there is a continuous need for novel reactions. Although serendipity has always played an important role in the discovery of novel (multicomponent) reactions, rational design strategies have become much more important over the past decade. In this Review, we present an overview of general strategies that allow the design of novel multicomponent reactions. The challenges and opportunities for the future will be discussed.
Synthesis and characterization of novel urethane‐siloxane copolymers with a high content of PCL‐PDMS‐PCL segments
Authors: Pergal Marija V. , Antić Vesna V. , Govedarica Milutin N. , Goäevac Dejan , Ostojić Sanja , Djonlagić Jasna 
Published: June 2011

AbstractNovel polyurethane copolymers derived from 4,4′‐methylenediphenyl diisocyanate (MDI), 1,4‐butanediol (BD) and α,ω‐dihydroxy‐[poly(caprolactone)‐poly (dimethylsiloxane)‐poly(caprolactone)] (α,ω‐dihydroxy‐(PCL‐PDMS‐PCL);
$ \overline M _{\rm{n}} $
= 6100 g mol−1) were synthesized by a two‐step polyaddition reaction in solution. In the synthesis of the polyurethanes, the PCL blocks served as a compatibilizer between the nonpolar PDMS blocks and the polar comonomers, MDI and BD. The synthesis of thermoplastic polyurethanes (TPU) with high soft segment contents was optimized in terms of the concentrations of the reactants, the molar ratio of the NCO/OH groups, and the time and temperature of the polyaddition reaction. The structure, composition, and hard MDI/BD segment length of the synthesized polyurethane copolymers were determined by 1H, 13C‐NMR, and two‐dimensional correlation (COSY, HSQC, and HMBC) spectroscopy, while the hydrogen bonding interactions in the copolymers were analyzed by FT‐IR spectroscopy. The influence of the reaction conditions on the structure, molecular weight, thermal, and some physical properties was studied at constant composition of the reaction mixture. A change in the molar ratio of the NCO/OH groups and the reaction conditions modified not only the molecular weight of the synthesized polyurethanes, but also the microstructure and therefore the thermal and physical properties of the copolymers. It was demonstrated that only PCL segments with high soft segment contents crystallize, thereby showing spherulitic morphology. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Zinc and tin xanthates in the coordination polymerization of propylene oxide
Authors: Ozturk Elif , Tas Eylem Tarkin , Tas Huseyin , Bolat Tuba , Soysal Ozlem , Alyuruk Kemal 
Published: June 2011

AbstractThe polymerization of propylene oxide with zinc and tin xanthates was studied. Polymerization with both systems was found to be a zeroth‐order, nonterminating process, where the molecular weight was controlled by transfer reactions. It is discussed that these observations were consistent with a mechanism in which the rate‐determining step was the addition of monomer on the growing chain rather than the coordination of the monomer to active sites. These catalysts turned out to be quite stable, even under semiclosed conditions. With zinc isopropyl xanthate, high conversions in short polymerization times could be obtained. The product had a very broad molecular weight distribution and could be split into crystallizable and amorphous fractions. The crystallizable fractions consisted of stereoregular segments separated from each other by stereoirregularities or regioirregularities. The degrees of polymerization of stereoregular segments (S1's) were estimated from melting point measurements. It was found that the melting points and, hence, average S1 values changed in different fractions. It was concluded that there was only one type of active center; however, the rates of wrong additions (e.g., head‐to‐head addition) of incoming monomer controlled the average S1 value of the chain. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Seasonal and clonal variations in technological and thermal properties of raw Hevea natural rubber
Authors: Galiani Patrini Danielle , Martins Maria Alice , de Souza Gonçalves Paulo , McMahan Colleen Marie , Capparelli Mattoso Luiz Henrique 
Published: June 2011

AbstractThis study was undertaken over a 10‐month period under environmental conditions within the state of Mato Grosso, Brazil, to evaluate the causes of variation in the technological and thermal properties of raw natural rubber (NR) from different clones of Hevea brasiliensis (GT 1, PR 255, FX 3864, and RRIM 600). These clones were chosen to represent good clones available in Brazil. The technological properties of raw NR were evaluated in terms of their dry rubber content (DRC), Wallace plasticity, plasticity retention index (PRI), and Mooney viscosity. The thermal performance was evaluated with the thermogravimetry (TG)/differential thermogravimetry (DTG) technique. There were significant variations (p < 0.01 and p < 0.05) between clones and tappings for all technological properties, except for the percentage DRC among the clones. Of the clones studied, clone PR 255 presented the highest sensitivity to thermooxidation, as measured by its PRI value. The clone type and period of the year did not significantly influence the thermal behavior (TG/DTG under a nitrogen atmosphere) among the four clones evaluated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
CO2/N2 separation ability and structural characteristics of poly(butadiene‐co‐acrylonitrile)‐based polyurethanes and hydrogenated nitrile rubbers
Authors: Wolińska‐Grabczyk Aleksandra , Jankowski Andrzej 
Published: June 2011

AbstractTwo families of rubbery polymers, commercial hydrogenated nitrile rubbers and synthesized poly(acrylonitrile‐co‐butadiene)‐based polyurethanes with different amount of nitrile groups were studied as CO2 selective membrane materials. The polymers were characterized by the techniques of FTIR, gel permeation chromatography, WAXD, and differential scanning calorimetry. The permeabilities of pure CO2 and N2 were measured using constant pressure/variable volume method at a feed pressure of 6 atm. With a higher amount of polar nitrile group within a given family of polymers, the permeability coefficient (P) was found to decrease, while the permselectivity (α) of these membranes was found to increase. The trade‐off between both transport parameters was less severe for the polyurethanes, which also showed much higher permeabilites. The results obtained were also discussed with respect to the polymer structure, and some relationships were found between P and Tg values. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Modified polydimethylsiloxane/polystyrene blended IPN pervaporation membrane for ethanol/water separation
Authors: Ahmed Iqbal , Pa Nasrul Fikry Che , Nawawi Mohd Ghazali Mohd , Rahman Wan Aizan Wan Abd 
Published: June 2011

AbstractIn this article a modified polydimethylsiloxane (PDMS) blended polystyrene (PS) interpenetrating polymer network (IPN) membranes supported by Teflon (polytetrafluoroethylene) ultrafiltration membrane were prepared for the separation of ethanol in water by pervaporation application. The relationship between the surface characteristics of the surface‐modified PDMS membranes and their permselectivity for aqueous ethanol solutions by pervaporation are discussed. The IPN supported membranes were prepared by sequential IPN technique. The IPN supported membrane were tested for the separation performance on 10 wt % ethanol in water and were characterized by evaluating their mechanical properties, swelling behavior, density, and degree of crosslinking. The results indicated that separation performance, mechanical properties, density, and the percentage of swelling of IPN membranes were influenced by degree of crosslink density. Depending on the feed temperature, the supported membranes had separation factors between 2.03 and 6.00 and permeation rates between 81.66 and 144.03 g m−2 h−1. For the azeotropic water–ethanol mixture (10 wt % ethanol), the supported membrane had at 30°C a separation factor of 6.00 and a permeation rate of 85 g m−2 h−1. Compared to the PDMS supported membranes, the PDMS/PS IPN supported blend membrane ones had a higher selectivity but a somewhat lower permeability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Interface adhesion properties of syndiotactic polypropylene/cellulose group composite: Relationship between chemical structure of coupling agent and reactivity for cellulose group
Authors: Nakatani Hisayuki , Iwakura Keisuke , Hamadate Masato , Okazaki Noriyasu , Aoyama Masakazu , Terano Minoru 
Published: June 2011

AbstractReinforcement of interfacial adhesion between syndiotactic polypropylene (SPP) and fibrous pure cellulose (FC) was performed by the FC silanizations with 3‐aminopropyltrimethoxysilane (APTMS), with hexyltrimethoxysilane (HTMS) and by an addition of a SPP grafted with dimethyl itaconate (SPP‐g‐DMI: number‐average molecular weight = 3.3 × 104, DMI cont. = 0.11 wt %), respectively. The adhesion and the morphology were improved by them, respectively. However, their behavior was considerably different. The hexyl group in the HTMS converted the FC surface into hydrophobicity, leading to the hindrance of the interhydrogen bonding in the FC. The silanized FC was embrittled with the increase of the degree of the silanization. In the case of the APTMS, the inter hydrogen bonding was kept because of the existence of the amino group. Whereas, the SPP‐g‐DMI was unable to penetrate into the cellulose because of its higher molecules, and the interhydrogen bonding was not hindered. The keeping the inter hydrogen bonding was important for the reinforcement of the tensile properties such as Young's modulus and tensile strength in the composite. Furthermore, the interfacial adhesion between the SPP and holocellulose (HC) was studied as well as the SPP/FC. Although the tensile properties were slightly improved by the APTMS silanization and by the addition of the SPP‐g‐DMI, respectively, the reactivity of the HC was much less than that of the FC. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Low formaldehyde emission particleboard panels realized through a new acrylic binder
Authors: Amazio Paola , Avella Maurizio , Emanuela Errico Maria , Gentile Gennaro , Balducci Francesco , Gnaccarini Alessio , Moratalla Julian , Belanche Manuel 
Published: June 2011

AbstractThe effectiveness of acrylic resins as low formaldehyde emission binders for particleboard production was explored. In particular, a multifunctional methacrylic monomer, ethoxylated bisphenol A dimethacrylate, classified as nonskin and eyes irritant, was selected and tested. In comparison panels realized with classic urea‐formaldehyde (UF) binder were also prepared. No significant differences were found through the morpholocigal analysis of samples prepared with the two different binders. Moreover, particleboard panels realized with the acrylic binder showed better mechanical properties and lower water absorption and thickness swelling in comparison with corresponding panels realized with the UF binders. Furthermore, the replacement of the UF with the acrylic binder did not affect thermal insulation properties of the panels. Formaldehyde release tests revealed that particleboard panels obtained by applying the acrylic binder can be classified as E1 following the European classification and even F**** following the stricter Japanese classification. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis and friction properties of copper/PMMA composites by soapless emulsion polymerization
Authors: Ma Xiaokun , Su Xiaodan , Zhou Bing , Zhao Xu , Tian Yumei , Wang Zichen 
Published: June 2011

AbstractCopper (Cu)‐doped polymethylmethacrylate (PMMA) composites were prepared by soapless emulsion polymerization. In this process, copper nanoparticles were modified by sodium oleate (SOA) and the surface property of Cu nanoparticles changed from hydrophilic to hydrophobic. The hydrophobic Cu nanoparticles could not only avoid the oxidation of Cu in air but also improve the compatibility between Cu nanoparticles and PMMA. The TEM micrographs revealed that Cu nanoparticles were encapsulated in PMMA polymer microspheres. In addition, the uniform Cu/PMMA composite microspheres could be synthesized in such a soapless emulsion polymerization process. It was worth mentioning that the friction property in oil was well improved when little nanocomposites were added into the base oil, which indicated that the composites can be widely used in lubricating oil. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis and characterization of new benzoxazine‐based phenolic resins from renewable resources and the properties of their polymers
Authors: Li Shengfang , Yan Shilin , Yu Jianying , Yu Bo 
Published: June 2011

AbstractTwo types of novel benzoxazine‐based phenolic resins from phenol‐furfural (PFB) and cardanol‐furfural (CFB) resins had been synthesized and the highly thermally stable polybenzoxazines were obtained by the thermal cure of the corresponding benzoxazine‐based phenolic resins. The chemical structure of benzoxazine‐based phenolic resins derived from renewable resources was confirmed by Fourier transform infrared (FTIR), 1H NMR, and gel permeation chromatography (GPC). FTIR spectrum and differential scanning calorimetry (DSC) showed that the monomers were thermally initiated and polymerized via ring‐opening polymerization. Thermogravimetric analysis indicated that the incorporation of furan groups could enhance the char yield and thermal stability. However, the long alkyl side chain from cardanol could increase the toughness, while decreasing the char yield and thermal stability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis of gold nanoparticles in hyperbranched polyol dispersions
Authors: Zhang Zhiliang , Shou Chongqi 
Published: June 2011

AbstractIn this study, a series of different generation hyperbranched poly(amine‐ester) with hydroxyl as terminal group were synthesized and used as protectants to synthesize gold nanoparticles with a facile and highly reproducible method. The effect of hyperbranched poly(amine‐ester) generation on size and their distribution of gold nanopartciels were discussed. The results of ultraviolet visible absorption spectroscopy, Transmission electron microscopy and scanning electron microscopy showed that the mean diameter were 24.3 ± 2.6 nm, 18.2 ± 2.1 nm, and 13.6 ± 1.5 nm corresponding to the different generation hyperbranched poly(amine‐ester), and the synthesized gold nanoparticles were almost monodisperse with a narrow size distribution. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of interchain interaction on optical properties of poly(p‐phenylene vinylene) derivative containing oxadiazole in backbone
Authors: Kong Fan , Fang Wendan , Yang Yimin , Qiu Teng 
Published: June 2011

AbstractWe have investigated the optical properties of poly [2‐methoxy‐5‐(2‐ethylhexyloxy)‐1,4‐phenylene vinylene] containing oxadiazole in backbone (MEH‐OPPV) in dilute tetrahydrofuran solution and solid solution films. There is a large dihedral angle between the two adjacent monomer units in MEH‐OPPV, which restrains interchain interactions and destroys the conjugation of the polymer to result in blue shifted absorption and emission spectra. The red shifted photoluminescence (PL) peak is continuously changed in the solid solution films with increasing the concentration of MEH‐OPPV. Comparison with the dilute solution, an obvious shoulder peak at 465 nm is found in the UV–vis absorption and PL excitation (PLE) spectra of the MEH‐OPPV film. The intensity of the PLE shoulder at 465 nm is increased with the concentration of MEH‐OPPV in the solid solution films, which is connected with the aggregation of the MEH‐OPPV chains. The interchain interactions are restrained and the π‐stack aggregates of the polymer chains can not form in the MEH‐OPPV due to the large dihedral angle, and then the interchain species are effectively suppressed in the MEH‐OPPV films. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Low‐temperature UV irradiation induced the color change kinetics and the corresponding structure development of PVC film
Authors: Yi Chuanbin , Sun Yanhong , Pi Hong , Guo Shaoyun 
Published: June 2011

AbstractThe low‐temperature ultraviolet (UV) irradiation equipment, developed in our Lab, was used to study the photo‐aging of poly (vinyl chloride) (PVC) films at low temperature. The color change kinetics and corresponding structure development of PVC film during low‐temperature UV aging were studied through L*a*b* coordinates Commission International d' Eclau‐age (CIE 1976 color space) and Ultraviolet spectrophotometer (UV–vis) and Fourier transform infrared spectroscopy (FTIR). It was found that the yellowness difference (▵b*) and color difference (▵E*) of the PVC film increased almost linearly with the aging time. Their values had a slower change at lower temperature. The kinetic study showed that the relationship between the velocity of coloration of the PVC film and the temperature agreed well with Arrhenius equation at low temperature. The activation energy of coloration of the PVC film was calculated. The FTIR spectra indicated that photo‐dehydrochloration, resulting in the generation of conjugated carbon–carbon double bonds, was the main reaction for PVC during photo‐aging at low temperature. Meanwhile, the photo‐oxidation was also obvious and could not be neglected. It clearly confirmed that the absorption peaks of conjugated carbon–carbon double bond increased and shifted to longer wavelength during photo‐aging in the UV‐abs analysis. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
Synthesis and properties of novel 4,4′‐biphenylene‐bridged flame‐retardant cyanate ester resin
Authors: Zhang Zhongyun , Yu Ruobing , Wang Fan , Wang Jialiang , Jiao Yangsheng 
Published: June 2011

AbstractThe bisphenol‐containing 4,4′‐biphenylene moiety was prepared by the reaction of 4,4′‐bis(methoxymethyl) biphenyl with phenol in the presence of p‐toluenesulfonic acid. The bisphenol was end‐capped with the cyanate moiety by reacting with cyanogen chloride and triethylamine in dichloromethane. Their structures were confirmed by Fourier transform infrared spectroscopy, 1H‐NMR, and elemental analysis. Thermal behaviors of cured resin were studied by differential scanning calorimetry, dynamic mechanical analysis, and TGA. The flame retardancy of cured resin was evaluated by limiting oxygen index (LOI) and vertical burning test (UL‐94 test). Because of the incorporation of rigid 4,4′‐biphenylene moiety, the cyanate ester (CE) resin shows good thermal stability (Tg is 256°C, the 5% degradation temperature is 442°C, and char yield at 800°C is 64.4%). The LOI value of the CE resin is 42.5, and the UL‐94 rating reaches V‐0. Moreover, the CE resin shows excellent dielectric property (dielectric constant, 2.94 at 1 GHz and loss dissipation factor, 0.0037 at 1 GHz) and water resistance (1.08% immersed at boiling water for 100 h). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011