bluuebunny/crossref_metadata_2025_split huggingface dataset:
Th2-Specific Immunity and Function of Peripheral T Cells Is Regulated by the p56Lck Src Homology 3 Domain
Authors: McCoy Margaret E. , Finkelman Fred D. , Straus David B. 
Published: August 2010

Abstract
T cell activation and effector function is essential for robust immunity. Ag TCR signals are known to regulate T lymphocyte differentiation, but the mechanisms involved in this regulation remain unclear. Recent work has demonstrated that the Src family protein tyrosine kinase p56Lck specifically links TCR signaling to activation of the MAPK pathway through the function of its Src homology 3 (SH3) domain. The MAPK pathway is involved in T cell activation and has previously been implicated in Th2 immunity. We have used Lck SH3 mutant knockin mice (LckW97A) to investigate the potential role of this regulatory mechanism in T lymphocyte activation and effector function. Our results demonstrate that Lck SH3 domain function regulates activation of T lymphocytes as indicated by reduced IL-2 production, CD69 induction, and proliferation of LckW97A T cells following TCR stimulation. Biochemical studies confirm that activation of the MAPK pathway is selectively altered following TCR ligation in LckW97A T lymphocytes. Phospho-ERK induction is reduced, but phospho-phospholipase Cγ1 induction and calcium mobilization are largely unaffected. Immunization with DNP–keyhole limpet hemocyanin, heat-killed Brucella abortus, or infection with Nippostrongylus brasiliensis demonstrates selectively impaired Th2 immunity with reduced serum levels of IgG1, IgE, and IL-4. In vitro studies show that LckW97A T cells can differentiate into Th2-type cells, but they form IFN-γ–producing cells under conditions that normally favor Th2 development. These data indicate that the Lck SH3 domain controls T lymphocyte activation by regulating MAPK pathway induction and demonstrate a novel role for Lck in the regulation of Th2-type immunity.
The Cystine/Glutamate Antiporter Regulates Dendritic Cell Differentiation and Antigen Presentation
Authors: D’Angelo June A. , Dehlink Eleonora , Platzer Barbara , Dwyer Peter , Circu Magdalena L. , Garay Jone , Aw Tak Yee , Fiebiger Edda , Dickinson Bonny L. 
Published: August 2010

Abstract
The major cellular antioxidant glutathione is depleted during HIV infection and in obesity. Although the consequence of glutathione depletion on immune function is starting to emerge, it is currently not known whether glutathione dysregulation influences the differentiation and maturation of dendritic cells (DCs). Moreover, the effect of glutathione depletion on DC effector functions, such as Ag presentation, is poorly understood. Glutathione synthesis depends on the cystine/glutamate antiporter, which transports the rate-limiting precursor cystine into the cell in exchange for glutamate. In this paper, we present a detailed study of antiporter function in DCs and demonstrate a role for the antiporter in DC differentiation and cross-presentation. We show that the antiporter is the major mechanism for transport of cystine and glutamate and modulates the intracellular glutathione content and glutathione efflux from DCs. Blocking antiporter-dependent cystine transport decreases intracellular glutathione levels, and these effects correlate with reduced transcription of the functional subunit of the antiporter. We further demonstrate that blocking antiporter activity interferes with DC differentiation from monocyte precursors, but antiporter activity is not required for LPS-induced phenotypic maturation. Finally, we show that inhibiting antiporter uptake of cystine interferes with presentation of exogenous Ag to class II MHC-restricted T cells and blocks cross-presentation on MHC class I. We conclude that aberrant antiporter function disrupts glutathione homeostasis in DCs and may contribute to impaired immunity in the diseased host.
Oxidative Phosphorylation Induces De Novo Expression of the MHC Class I in Tumor Cells through the ERK5 Pathway
Authors: Charni Seyma , de Bettignies Geoffroy , Rathore Moeez G. , Aguiló Juan I. , van den Elsen Peter J. , Haouzi Delphine , Hipskind Robert A. , Enriquez José Antonio , Sanchez-Beato Margarita , Pardo Julián , Anel Alberto , Villalba Martin 
Published: August 2010

Abstract
Most cancer cells use anaerobic-like glycolysis to generate energy instead of oxidative phosphorylation. They also avoid recognition by CTLs, which occurs primarily through decreasing the level of MHC class I (MHC-I) at the cell surface. We find that the two phenomena are linked; culture conditions that force respiration in leukemia cells upregulate MHC-I transcription and protein levels at the cell surface, whereas these decrease in cells forced to perform fermentation as well as in leukemia cells lacking a functional mitochondrial respiratory chain. Forced respiration leads to increased expression of the MAPK ERK5, which activates MHC-I gene promoters, and ERK5 accumulation in mitochondria. Respiration-induced MHC-I upregulation is reversed upon short hairpin RNA-mediated ERK5 downregulation and by inactive mutants of ERK5. Moreover, short hairpin RNA for ERK5 leukemia cells do not tolerate forced respiration. Thus, the expression of ERK5 and MHC-I is linked to cell metabolism and notably diminished by the metabolic adaptations found in tumor cells.
Homeostatic Turnover of Virus-Specific Memory CD8 T Cells Occurs Stochastically and Is Independent of CD4 T Cell Help
Authors: Choo Daniel K. , Murali-Krishna Kaja , Anita Rustom , Ahmed Rafi 
Published: August 2010

Abstract
Memory CD8 T cells persist by Ag-independent homeostatic proliferation. To examine the dynamics of this cell turnover, we transferred lymphocytic choriomeningitis virus specific memory CD8 T cells into naive mice and analyzed their in vivo division kinetics longitudinally in individual recipients.Using mathematical modeling, we determined that proliferation of this stably maintained memory CD8 T cell population was homogeneous and stochastic with a small fraction of cells completing division at any given time with an intermitotic interval of 50 d. This homeostatic turnover was comparable between memory CD8 T cells of different viral epitope specificities and also the total memory phenotype (CD44high) CD8 T cells. It is well established that CD4 T cell help is critical for maintenance of CD8 T cells during chronic infections, but recent studies have suggested that CD4 T cell help is also required for maintenance of memory CD8 T cells following acute infections. Hence, we assessed the role of CD4 T cells in Ag-independent maintenance of memory CD8 T cells. Consistent with previous reports, we found that memory CD8 T cells declined when transferred into MHC class II-deficient mice. However, their numbers were maintained stably when transferred into CD4 T cell-deficient mice. Interestingly, their homeostatic proliferation, ability to make recall responses, and phenotype were independent of CD4 T cell help because none of these qualities were affected when memory CD8 T cells were transferred and maintained in either MHC class II- or CD4-deficient recipients.
Reversibility of Interacting Fleming–Viot Processes with Mutation, Selection, and Recombination
Authors: Feng Shui , Schmuland Byron , Vaillancourt Jean , Zhou Xiaowen 
Published: August 2010

Abstract Reversibility of the Fleming-Viot process with mutation, selection, and recombination is well understood. In this paper, we study the reversibility of a system of Fleming-Viot processes that live on a countable number of colonies interacting with each other through migrations between the colonies. It is shown that reversibility fails when both migration and mutation are non-trivial.
New approach to chemical functionalization of poly(2‐chloroxylylene) thin films
Authors: Bolognesi Alberto , Arnautov Sergey , Charmet Jérôme , Laux Edith , Keppner Herbert 
Published: August 2010

Abstract3‐(8‐Octenyl)thiophene was used for successful preparation of functionalized poly‐(2‐chloro‐xylylene) (PCX) layers in the course of CVD process. The set of spectral methods used has allowed us to conclude that such modification is based on the chemical reaction of double bonds with xylylene radicals. Functionalized films were used for further chemical transformation in the course of polycondensation of 3‐octylthiophene. Resulted samples are bilayer films and polythiophene layer is chemically connected with PCX one. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Molecularly imprinted polymer microspheres with nanopore cavities prepared by precipitation polymerization as new carriers for the sustained release of dipyridamole
Authors: Javanbakht Mehran , Mohammadi Somayeh , Esfandyari‐Manesh Mehdi , Abdouss Majid 
Published: August 2010

AbstractImprinted polymers are now being increasingly considered for active biomedical uses such as drug delivery. In this work, the use of molecularly imprinted polymers (MIPs) in designing new drug delivery devices was studied. Imprinted polymers were prepared from methacrylic acid (MAA) (functional monomer), ethylene glycol dimethacrylate (cross‐linker), and dipyridamole (DIP) (as a drug template) using precipitation polymerization method. The influence of the template/functional monomer proportion and pH on the achievement of MIPs with nanopore cavities with a high enough affinity for the drug was investigated. The small pores (average 3.9 nm) in the imprinted microspheres show excellent retention properties for the target analyte. The polymeric devices were further characterized by FT‐IR, thermogravimetric analysis, scanning electron microscopy, photon correlation spectroscopy, Brunauer‐Emmett‐Teller analysis, and binding experiments. The imprinted polymers showed a higher affinity for DIP and a slower release rate than the nonimprinted polymers. The controlled releases of DIP from the prepared imprinted polymers were investigated by an in vitro dissolution test by measuring the absorbance at 284 nm by means of a UV–Visible spectrophotometer. Loaded imprinted microsphers showed very slow release in various solutions such as phosphate buffer solution (pH 6.8), HCl (pH 1.0) and mixture of HCl and MeOH at 37.0 ± 0.5°C and were able to prolong DIP release for more than two days. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Mechanical properties of hydroxyapatite‐filled ethylene vinyl acetate copolymer composites: Effect of particle size and morphology
Authors: Velayudhan Shiny , Ramesh P. , Varma H. K. 
Published: August 2010

AbstractPliable and bioactive composites made of hydroxyapatite (HAP) and ethylene vinyl acetate (EVA) copolymer were developed for the repair of defective cranium. This article describes the mechanical properties of HAP–EVA composites. The effects of HAP particle size and morphology of HAP on the properties of resultant composites were investigated using various techniques. It was found that the composites containing smaller HAP particles had higher values of tensile modulus, flexural modulus, and impact strength. Examination of the fracture surfaces revealed that only a mechanical bond existed between the filler and the matrix. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Asymmetric polyurethane membrane with in situ‐generated nano‐TiO2 as wound dressing
Authors: Chen Yi , Yan Lidan , Yuan Tun , Zhang Qiyi , Fan Haojun 
Published: August 2010

AbstractFor potential application as an ideal wound dressing, a novel asymmetric polyurethane membrane with in situ‐generated nano‐TiO2 (PUNT) was successfully prepared via a combination of solvent evaporation, wet phase inversion, and organic–inorganic hybridization. According to this combination method, the PUNT membrane consisted of an integral and dense skin layer supported by a porous sublayer, with nano‐TiO2 particles dispersed evenly throughout the sample. The skin layer was found to be impermeable to bacteria penetration, and the porous sublayer was designed for absorbing high amounts of exudates. Nitrogen adsorption/desorption experiment proved that extra mesopores were created in the PUNT membrane after organic–inorganic hybridization, which resulted in promoted gas permeability, water vapor transmission rate, and exudate absorption capability. The PUNT membrane, as a consequence, could accelerate gas exchange and also provide an optimal level of moisture over the wound beds without risking dehydration or exudate accumulation. Shake flask testing and cell culture (L929) assay indicated that the PUNT membrane exhibited antibacterial activity against Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus, whereas showed no cytotoxicity. From in vivo animal studies, the curative effect of PUNT membrane was found to be better than gauze and a commercial polyurethane membrane dressing. These results indicated that the PUNT membrane with multifunctions prepared in this study has potential for application as an ideal wound dressing. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Nonisothermal crystallization behavior of a biodegradable segmented copolymer constituted by glycolide and trimethylene carbonate units
Authors: Díaz‐Celorio Elena , Franco Lourdes , Puiggalí Jordi 
Published: August 2010

AbstractNonisothermal crystallization of a segmented copolymer constituted by glycolide and trimethylene carbonate units was studied from both the melt and the glass state by optical microscopy, differential scanning calorimetry and time‐resolved X‐ray diffraction techniques. Positive spherulites with a fibrilar appearance were always obtained and corresponded to the crystallization of the polyglycolide hard segments. A single crystallization regime and the kinetic parameters were inferred from optical microscopy data on crystallizations performed at different cooling/heating rates. The parameters were in good agreement with values previously deduced from isothermal experiments. Isoconversional data of melt and glass nonisothermal crystallizations were combined to obtain the Lauritzen and Hoffman parameters from calorimetric data. Results revealed again the existence of a single crystallization regime with a secondary nucleation constant close to that deduced from isothermal DSC experiments. Morphological changes occurring during the hot and cold crystallization were evaluated by time‐resolved SAXS/WAXD experiments employing synchrotron radiation. Measurements showed that significant differences on the lamellar thicknesses exist depending on the crystallization process. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Acetylsalicylic acid loading and release studies of the PMMA‐g‐polymeric oils/oily acids micro and nanospheres
Authors: Kılıçay Ebru , Çakmaklı Birten , Hazer Baki , Denkbaş Emir Baki , Açıkgöz Bektaş 
Published: August 2010

AbstractPoly(methyl methacrylate) (PMMA) and PMMA copolymers derived from plant oils (Polylinseed oil‐g‐PMMA, Polysoybean oil‐g‐PMMA, Polylinoleic acid‐g‐PMMA (PLina‐g‐PMMA) and Polyhydroxy alkanoate‐ sy‐g‐Polylinoleic acid‐g‐PMMA (PHA‐g‐PLina‐g‐PMMA)) as hydrophobic polymers, a series of hydrophobic microsphere or nanosphere dispersions, were prepared by the emulsion/solvent evaporation method. The diameters of the nanospheres and microspheres were measured by dynamic light scattering with a zetasizer, optically and by scanning electron microscopy. The magnetic quality of the microspheres was determined by the electron spin resonance technique. Acetylsalicylic acid (aspirin, ASA) was used as a model drug and loaded into the microspheres during the preparation process. The effect of the stirring rate over the size and size distribution of the micro/nanospheres was evaluated, and the effects of copolymer types derived from plant oil/oily acids and the copolymer/drug ratios were evaluated. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Bamboo fiber reinforced polypropylene composites and their mechanical, thermal, and morphological properties
Authors: Chattopadhyay Sanjay K. , Khandal R. K. , Uppaluri Ramagopal , Ghoshal Aloke K. 
Published: August 2010

AbstractShort bamboo fiber reinforced polypropylene composites were prepared by incorporation of various loadings of chemically modified bamboo fibers. Maleic anhydride grafted polypropylene (MA‐g‐PP) was used as compatibilizer to improve fiber–matrix adhesion. The effects of bamboo fiber loading and modification of the resin on the physical, mechanical, thermal, and morphological properties of the bamboo reinforced modified PP composites were studied. Scanning electron microscopy studies of the composites were carried out on the interface and fractured surfaces. Thermogravimetric analysis and IR spectroscopy were also carried out. At 50% volume fraction of the extracted bamboo fiber in the composites, considerable increase in mechanical properties like impact, flexural, tensile, and thermal behavior like heat deflection temperature were observed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Study on thermal behavior of impact polypropylene copolymer and its fractions
Authors: Zhang Chunhui , Shangguan Yonggang , Chen Ruifen , Zheng Qiang 
Published: August 2010

AbstractAn impact polypropylene copolymer (IPC) was fractionated into three fractions using n‐octane as solvent by means of temperature‐gradient extraction fractionation. The glass transitions, melting, and crystallization behavior of these three fractions were studied by modulated differential scanning calorimeter (MDSC) and wide‐angle X‐ray diffraction (WAXD). In addition, successive self‐nucleation and annealing (SSA) technique was adopted to further examine the heterogeneity and the structure of its fractions. The results reveal that the 50°C fraction (F50) mainly consists of ethylene‐propylene random copolymer and the molecular chains may contain a few of short but crystallizable propylene and/or ethylene unit sequences; moreover, the lamellae thicknesses of the resulting crystals are extremely low. Furthermore, 100°C fraction (F100) mainly consist of some branched polyethylene and various ethylene‐propylene block copolymers in which some ethylene and propylene units also randomly arrange in certain segments, and some polypropylene segments can form crystals with various lamellae thickness. An obvious thermal fractionation effect for F100 samples after being treated by SSA process is ascribed to the irregular and nonuniform arrangement of ethylene and propylene segments. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Preparation and surface properties of core‐shell polyacrylate latex containing fluorine and silicon in the shell
Authors: Xiao Xinyan , Xu Rui 
Published: August 2010

AbstractThe core‐shell polyacrylate latex particles containing fluorine and silicon in the shell were successfully synthesized by a seed emulsion polymerization, using methyl methacrylate (MMA) and butyl acrylate (BA) as main monomers, dodecafluoroheptyl methacrylate (DFMA), and γ‐(methacryloxy) propyltrimethoxy silane (KH‐570) as functional monomers. The influence of the amount of fluorine and silicon monomers on the emulsion polymerization process and the surface properties of the latex films were discussed, and the surface free energy of latex films were estimated using two different theoretical models. The emulsion and its films were characterized by particle size distribution (PSD) analysis, transmission electron microscopy (TEM), Fourier transform infrared spectrum (FTIR), nuclear magnetic resonance (1H‐NMR and 19F‐NMR) spectrometry, contact angle (CA) and X‐ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), and thermogravimetry (TG) analysis. The results indicate that the average particle size of the latex particles is about 160 nm and the PSD is narrow, the synthesized latex particles exist with core‐shell structure, and a gradient distribution of fluorine and silicon exist in the latex films. In addition, both the hydrophobicity and thermal stability of the latex films are greatly improved because of the enrichment of fluorine and silicon at the film‐air interface, and the surface free energy is as low as 15.4 mN/m, which is comparable to that of polytetrafluoroethylene (PTFE). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Natural and artificial weathering effects on cold‐cured epoxy resins
Authors: Lettieri Mariateresa , Frigione Mariaenrica 
Published: August 2010

AbstractThree cold‐cured epoxy resins, specifically designed as structural adhesives for rehabilitation or renewal applications of civil infrastructures and cultural heritage, were submitted to natural and artificial weathering. We evaluated the variations in the thermal and mechanical properties and color changes after an artificial treatment carried out at 70°C and 75% relative humidity and after natural weathering, performed in two areas of South Italy, both located adjacent to the Mediterranean Sea. The variations in properties due to both natural exposure and artificial weathering were qualitatively similar. However, the selected artificial weathering procedure appeared excessively severe compared to the weathering that occurred after outdoor exposure. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of the inner wall cooling rate on the structure and properties of a polyethylene pipe extruded at a high rotation speed
Authors: Nie Min , Bai Shibing , Wang Qi 
Published: August 2010

AbstractA novel rotation extrusion processing system was self‐designed to prepare high‐performance polyethylene (PE) pipes. In this study, during the extrusion of the PE pipes at a high mandrel rotation speed, compressed air, as a cooling medium, was introduced through their interior to achieve the quick cooling of the inner wall and the effects of the inner wall cooling rate on the microstructure and mechanical properties of the obtained PE pipes were investigated. The experimental results showed that in contrast to conventional extrusion, the molecular orientation deviated from the axial direction under a high mandrel rotation speed and was fixed by the inner wall cooling; with increasing cooling rate, the orientation degree also increased. On the other hand, cooling promoted the augmentation of spherulites. So when the cooling rate reached a certain high point, the effect of cooling on the formation of spherulites was stronger than that on the fixation of the orientation. A much higher cooling rate decreased the orientation degree, which was closely related to the performance of the PE pipe. As a result, there was an optimal cooling rate of the inner wall during the rotation extrusion for better performance of the PE pipe. When the cooling rate was 1.5°C/s, the hoop strength of the PE pipe produced by the novel extrusion method increased from the original 24.1 MPa up to 37.1 MPa without a decrease in the axial strength, and the pipe's crack initiation time increased from 27 to 70 h. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011