bluuebunny/crossref_metadata_2025 huggingface dataset:
Biocompatible polymer blends: Effects of physical processing on the molecular interaction of poly(vinyl alcohol) and poly(vinyl pyrrolidone)
Authors: Jones S. A. , Martin G. P. , Royall P. G. , Brown M. B.
Published: September 2005

Blending is a very effective method for manufacturing new polymeric materials; however, the process used to combine two polymers can influence the physicochemical properties of the final product. As such, the aim of this study was to investigate how the rapid removal of a solvent from a composite by the spray drying of partially hydrolyzed poly(vinyl alcohol) (PVA)/poly(vinyl pyrrolidone) (PVP) altered the solid‐state properties of the material compared to casting the blend within a film. Although thermal analysis showed that PVP acted as a plasticizer, reducing the melting point of PVA, spray drying the product rather than using a film‐casting procedure improved its solid‐state stability (increasing the glass transition) and resulted in the formation of a second crystalline phase within the material. Spectroscopic studies suggested that the manufacturing‐induced variance in the solid‐state properties of the PVA/PVP blends originated from structural differences in the composite caused by the processing method employed to form the blend. Although blending should still be considered a viable method of generating novel polymeric material, this study illustrated that through careful manipulation of the actual manufacturing process, the solid‐state properties of the product can be altered. This could open a whole range of novel applications for traditionally used polymer composites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2290–2299, 2005
Melting behavior and nonisothermal crystallization kinetics of polyamide 6/polyamide 66 molecular composites via in situ polymerization
Authors: Li Yulin , Liu Hongzhi , Zhang Ying , Yang Guisheng
Published: September 2005

The melting behavior and nonisothermal crystallization kinetics of pure polyamide 6 (PA 6) and its molecular composites with polyamide 66 (PA 66) were investigated with differential scanning calorimetry. The PA 6/PA 66 composites had one melting peak, whereas the coextruded PA 6/PA 66 blends had two melting peaks. With the addition of PA 66 to PA 6 via in situ anionic polymerization, the melting temperature, crystallization temperature, and crystallinity of PA 6 in the composites decreased. The half‐time of nonisothermal crystallization increased for a PA 6/PA 66 molecular composite containing 12 wt % PA 66, in comparison with that of pure PA 6. The commonly used Ozawa equation was used to fit the nonisothermal crystallization of pure PA 6 and its composites. The Ozawa exponent values in the primary stage were equal to 1.28–3.03 and 1.28–2.97 for PA 6 and its composite with 12 wt % PA 66, respectively, and this revealed that the mechanism of primary crystallization of PA 6 and PA 6/PA 66 was mainly heterogeneous nucleation and growth. All the results indicated that the incorporation of PA 66 into PA 6 at the molecular level retarded the crystallization of PA 6. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2172–2177, 2005
Changes in the microstructure and characteristics of carbon/carbon composites with mesophase mesocarbon microbeads added during graphitization
Authors: Hu Hsien‐Lin , Ko Tse‐Hao , Kuo Wen‐Shyong
Published: September 2005

Carbon/carbon (C/C) composites were prepared from oxidative PAN fiber felts, a resol‐type phenolic resin, and mesophase pitch derived from coal tar. In this study, the effects on mesocarbon microbeads (MCMBs), flexural strength, flexural moduli, electric conductivity, and thermal conductivity of C/C composites with a mesophase content ranging from 0 to 30 wt % were examined during pyrolysis. The results show that the C/C composite with the addition of 10–30 wt % mesophase had a higher density, greater stacking size, and higher preferred orientation than the C/C composites without any mesophase during heat treatment. These composites also exhibited an improvement in flexural strength from 19.7 to 30.3%. The flexural moduli of these composites with mesophase added increased by 15.1 to 31.3% compared to that with no mesophase added. These composites also showed improved electric conductivity, from 15.1 to 43.7%, and thermal conductivity, from 12 to 31.3%. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2178–2190, 2005
Toward a viscoelastic modeling of anisotropic shrinkage in injection molding of amorphous polymers
Authors: Kwon Keehae , Isayev A. I. , Kim K. H.
Published: September 2005

A novel approach to predict anisotropic shrinkage of amorphous polymers in injection moldings was proposed using the PVT equation of state, frozen‐in molecular orientation, and elastic recovery that was not frozen during the process. The anisotropic thermal expansion and compressibility affected by frozen‐in molecular orientation were introduced to determine the anisotropy of the length and width shrinkages. Molecular orientation calculations were based on the frozen‐in birefringence determined from frozen‐in stresses by using the stress‐optical rule. To model frozen‐in stresses during the molding process, a nonlinear viscoelastic constitutive equation was used with the temperature‐ and pressure‐dependent relaxation time and viscosity. Contribution of elastic recovery that was not frozen during the molding process and calculated from the constitutive equation was used to determine anisotropic shrinkage. Anisotropic shrinkages in moldings were measured at various packing pressures, packing times, melt temperatures, and injection speeds. The experimental results of frozen‐in birefringence and anisotropic shrinkage were compared with the simulated data. Experimental and calculated results indicate that shrinkage is highest in the thickness direction, lowest in the width direction, and intermediate in the flow direction. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2300–2313, 2005
Reactive mixing of PET and PET/PP blends with glycidyl methacrylate–modified styrene‐b‐(ethylene‐co‐olefin) block copolymers
Authors: Pracella Mariano , Chionna Donatella , Pawlak Andrzej , Galeski Andrzej
Published: September 2005

Styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene (SEBS) and styrene‐b‐(ethylene‐co‐propylene) (SEP, SEPSEP) block copolymers with different styrene contents and different numbers of blocks in the copolymer chain were functionalized by melt radical grafting with glycidyl methacrylate (GMA) and employed as compatibilizers for PET‐based blends. Binary blends of PET with both functionalized (SEBS‐g‐GMA, SEP‐g‐GMA, SEPSEP‐g‐GMA) and neat (SEBS, SEP, SEPSEP) copolymers (75 : 25 w/w) and ternary blends of PET and PP (75 : 25 w/w) with various amounts (2.5–10 phr) of both modified and unmodified copolymers were prepared in an internal mixer, and their properties were evaluated by SEM, DSC, melt viscosimetry, and tensile and impact tests. The roles of the chemical structure, grafting degree, and concentration of the various copolymers on blend compatibilization was investigated. The blends with the grafted copolymers showed a neat improvement of phase dispersion and interfacial adhesion compared to the blends with nonfunctionalized copolymers. The addition of grafted copolymers resulted in a marked increase in melt viscosity, which was accounted for by the occurrence of chemical reactions between the epoxide groups of GMA and the carboxyl/hydroxyl end groups of PET during melt mixing. Blends with SEPSEP‐g‐GMA and SEBS‐g‐GMA, at concentrations of 5–10 phr, showed a higher compatibilizing effect with enhanced elongation at break and impact resistance. The effectiveness of GMA‐functionalized SEBS was then compared to that of maleic anhydride–grafted SEBS. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2201–2211, 2005
Phase behaviors of polymer blend(PEO–PPO) electrolyte/LiCF3SO3 systems in lithium battery
Authors: Choi Yong Su , Bae Young Chan , Sun Yang Kook
Published: September 2005

Polymer blend (poly(ethylene oxide) (PEO)–poly(propylene oxide) (PPO)) systems with two different mole ratios, complexed with LiCF3SO3 salt, have been characterized at various temperatures and compositions using a thermo‐optical analysis (TOA) technique. We also developed a new melting point depression theory based on the modified perturbed hard sphere chain model to interpret phase behavior of polymer blend electrolyte systems. The obtained results show that the eutectic points move toward higher Tm and lower weight fraction of salt with decreasing PEO mole ratio and also indicate that the mole ratio of PEO–PPO for each polymer blend plays an important role in determining the eutectic point of the polymer blend system. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2314–2319, 2005
The interrelation among network structures, molecular transport of solvent, and creep behaviors of TiB2 ceramic containing butyl rubber composites
Authors: El‐Tantawy Farid
Published: September 2005

Swelling of polymer composites in solvents has become one of the major problems in the use of polymer composites exposed to petroleum products. As a possible solution to the problem, this experimental study was conducted to examine the potential application of TiB2 ceramic in butyl rubber (IIR) composites. The effect of TiB2 content on the curing kinetics of IIR composites was studied using a torque rheometer technique. The effect of TiB2 on the network structure was investigated in terms of the crosslinking density, interparticle distance between conducting particles, surface tension, glass transition temperature, degree of crystallinity, scanning electron microscopy, and X‐ray analysis. Moreover, the effect of TiB2 content on the molecular transport of solvent (kerosene) was examined by means of degree of swelling, solvent interaction parameters, volume fraction of rubber, interparticle distance after swelling, penetration rate of solvent, mean diffusion coefficient, cohesive energy density of polymer, standard entropy, standard enthalpy, and standard free energy of IIR composites. It was ascertained that with increasing TiB2 content the degree of swelling shifts to a lower value. The main reason was interpreted as the introduction of good interface adhesion of TiB2 with rubber matrix, which tends to block the diffusion of solvent molecules. The effect of TiB2 content on hardness, tensile strength, Young's modules, and elongation at break is discussed. An apparent steady‐state creep of butyl rubber IIR/TiB2 composites is evident under different constant stresses at room temperature. The strain rate of steady‐state creep showed a dependence on stress and TiB2 volume fraction. The stress sensitivity parameter, viscosity coefficient, and activation volume for samples loaded with different content of TiB2 were estimated. It is apparent that these new composites should be very useful for solvent permeation resistance at high TiB2 loading level with good mechanical properties. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2226–2235, 2005
Effect of the reaction conditions on the photopolymerization of methyl methacrylate by diethyl dithiocarbamato‐(1,2)‐propane diol
Authors: Bhuyan P. K. , Kakati D. K.
Published: September 2005

The photopolymerization of methyl methacrylate (MMA) through the use of diethyl dithiocarbamato‐(1,2)‐propane diol (DCPD) was studied. The photoinitiator was synthesized from 3‐chloro‐1,2‐propane diol and sodium diethyl dithiocarbamate in a solvent mixture of acetone and anhydrous ethanol. The photopolymerization was carried out in a Heber multilamp photochemical reactor (COMPACT‐LP‐MP88) (Heber Scientific, Chennai, India) at 254 nm. The effects of the reaction conditions on the polymerization of MMA were studied. The conversion and molecular weight increased with an increase in the monomer concentration and reaction time. However, for the DCPD‐to‐MMA molar ratio, a critical value was found for maximum conversion. The results suggested the living radical nature of the photoinitiator, which was further investigated by the preparation of a block copolymer with styrene. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2320–2328, 2005
Preparation and properties of poly(methyl methacrylate)/iron carbonate(p) nanocomposites
Authors: Chou Yi‐Chun , Lin C. B. , Yeh Hsiao‐Yun
Published: September 2005

The mass transport of methanol mixed with ferric chloride hexahydrate (FeCl3 · 6H2O) in poly(methyl methacrylate) and poly(methyl methacrylate)/iron carbonate particulate(p) nanocomposites is prepared by chemical vapor crystallization and the resulting materials, which are subjected to characterization to evaluate thermal and optical properties, have been investigated. Mass transport is an anomalous and endothermic process and satisfies the van't Hoff plot. We have prepared successfully poly(methyl methacrylate)(PMMA)/iron carbonate particulates nanocomposites using CO2 gas slowly diffused into saturated solvent mixture‐treated poly(methyl methacrylate) for 48 h. After SEM observation, approximately 80 nm iron carbonate particulates were precipitated and evenly distributed in the poly(methyl methacrylate) matrix. In comparison with solvent mixture‐treated PMMA, the cut‐off wavelength of transmittance in nanocomposites shifts to the shorter wavelength side (red shift). The presence of nanoscale iron carbonate particulates increased the glass transition temperature of the nanocomposites as determined by differential scanning calorimeter, and the glass transition temperature increased with increasing content of nanoscale iron carbonate particulates. The FTIR spectra of solvent mixture‐treated poly(methyl methacrylate) and nanocomposites are also studied. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2329–2338, 2005
Synthesis and characterization of novel polyurethanes based on 1,3‐bis(hydroxymethyl) benzimidazolin‐2‐one and 1,3‐bis(hydroxymethyl) benzimidazolin‐2‐thione hard segments
Authors: Raghu A. V. , Gadaginamath G. S. , Aminabhavi Tejraj M.
Published: September 2005

Novel polyurethanes (PUs) based on 1,3‐bis(hydroxymethyl) benzimidazolin‐2‐one and 1,3‐bis(hydroxymethyl) benzimidazolin‐2‐thione as hard segments with two aromatic diisocyanates, viz., 4,4′‐diphenylmethane diisocyanate and toluene 2,4‐diisocyanate, were prepared. Polymer structures were established by Fourier transform infrared and nuclear magnetic resonance spectroscopy. Morphology of the PUs was studied by differential scanning calorimetry and thermogravimetry. All PUs contain domains of crystalline and amorphous structures as indicated by X‐ray diffraction experiments. Furthermore, polymers were insoluble in the majority of organic solvents and, hence, their solution characterization was not possible. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2236–2244, 2005
Thermal characterization and thermal degradation of copolyimides containing fluorine and phosphine oxide
Authors: Tang Wanjun , Chen Donghua , Yang Zhilan , Zhang Aiqing , Peng Yuhua
Published: September 2005

A series of copolyimides containing different ratios of fluorine and phosphine oxide were synthesized. The copolymers were characterized with Fourier transform infrared, differential scanning calorimetry, and thermogravimetric analysis measurements. The copolymers were thermally stable up to 700 K and exhibited glass‐transition temperatures in the range of 495–562 K. The glass‐transition temperatures of the copolymers decreased with an increase in the phosphine oxide content. The thermal decomposition behavior of the copolymers was investigated. The copolymers with higher phosphine oxide contents displayed lower onset decomposition temperatures and char yields. A new method involving the multiple‐rate isotemperature was used to define the most possible mechanism [G(α)] for the reactions. The overall kinetic model function of the thermal decomposition of these copolymers obeyed the Avrami–Erofeev model equation, G(α) = [−ln(1 − α)]1/m, where α is the conversion degree. The apparent kinetic parameters of the degradation processes were also obtained. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2139–2143, 2005
Erratum: Future pricing through homogeneous semi‐Markov processes
Authors: Di Biase Giuseppe , Janssen Jacques , Manca Raimondo
Published: September 2005

The original article to which this Erratum refers was published in Applied Stochastic Models in Business and Industry 2005;21 (3):241–249
Proteome analysis to assess physiological changes in Escherichia coli grown under glucose‐limited fed‐batch conditions
Authors: Raman Babu , Nandakumar M.P. , Muthuvijayan Vignesh , Marten Mark R.
Published: September 2005

Proteome analysis was used to compare global protein expression changes in Escherichia coli fermentation between exponential and glucose‐limited fed‐batch phase. Two‐dimensional gel electrophoresis and MALDI‐TOF mass spectrometry were used to separate and identify 49 proteins showing >2‐fold difference in expression. Proteins upregulated during exponential phase include ribonucleotide biosynthesis enzymes and ribosomal recycling factor. Proteins upregulated during fed‐batch phase include those involved in high‐affinity glucose uptake, transport and degradation of alternate carbon sources and TCA cycle, suggesting an enhanced role of the cycle under glucose‐ and energy‐limited conditions. We report the upregulation of several putative proteins (ytfQ, ygiS, ynaF, yggX, yfeX), not identified in any previous study under carbon‐limited conditions. © 2005 Wiley Periodicals, Inc.
Novel quantitative tools for engineering analysis of hepatocyte cultures in bioartificial liver systems
Authors: Sharma N.S. , Ierapetritou M.G. , Yarmush M.L.
Published: September 2005

Extracorporeal bioartificial liver devices (BAL) are perhaps among the most promising technologies for the treatment of liver failure, but significant technical challenges remain in order to develop systems with sufficient processing capacity and of manageable size. One key limitation is that during BAL operation, when the device is exposed to plasma from the patient, hepatocytes are prone to accumulate intracellular lipids and exhibit poor liver‐specific functions. Based on hepatic intermediary metabolism, we have utilized mathematical programming techniques to optimize the biochemical environment of hepatocyte cultures towards the desired effect of increased albumin and urea synthesis. To investigate the feasible range of optimal hepatic function, we have obtained a Pareto optimal set of solutions corresponding to liver‐specific functions of urea and albumin secretion in the metabolic framework using multiobjective optimization. The importance of amino acids in the supplementation and the criticality of the metabolic pathways have been investigated using logic‐based programming techniques. Since the metabolite measurements are bound to be patient specific, and hence subject to variability, uncertainty has to be integrated with system analysis to improve the prediction of hepatic function. We have used the concept of two stage stochastic programming to obtain robust solutions by considering extracellular variability. The proposed analysis represents a new systematic approach to analyze behavior of hepatocyte cultures and optimize different operating parameters for an extracorporeal device based on real‐time conditions. © 2005 Wiley Periodicals, Inc.
Strain stability in biological systems treating recalcitrant organic compounds
Authors: Emanuelsson E.A.C. , Baptista I.I.R. , Mantalaris A. , Livingston A.G.
Published: September 2005

The availability of molecular probing technology in recent years has facilitated investigation of microbial community composition during biotreatment of organic wastes. Particularly, it has allowed the study of microbial culture stability and correlation between stability and treatment performance. However, most studies to date have only addressed mixed cultures and there is limited information regarding single strain stability. Here we have investigated the microbial community dynamics in two bioreactors, each inoculated with a pure bacterial strain capable of degrading a recalcitrant substrate, namely Xanthobacter aut. GJ10 degrading 1,2‐dichloroethane (DCE) and Burkholderia sp. JS150 degrading monochlorobenzene (MCB). Universal and strain specific 16S rRNA oligonucleotide probes were designed and used to follow strain stability. The bioreactor fed with DCE was functionally stable and the percentage of GJ10 cells in the community remained high (around 95% of total cells) throughout, even after introduction of foreign microorganisms. The bioreactor fed with MCB was also functionally stable, but in contrast to the DCE bioreactor, probing results revealed the disappearance of strain JS150 from the bioreactor within a week. The difference in behavior between the two systems is attributed to the specific pathway required to degrade DCE. © 2005 Wiley Periodicals, Inc.
Cell cycle synchronization of Cupriavidus necator by continuous phasing measured via flow cytometry
Authors: Fritsch M. , Starruß J. , Loesche A. , Mueller S. , Bley Th.
Published: September 2005

The continuous phasing technique was successfully used to obtain a high degree of cell cycle synchrony in cultures of the model organism Ralstonia eutropha JMP 134 (today reclassified into Cupriavidus necator). The responses of the organism were evaluated with flow cytometric determinations of DNA contents and cell size (by fluorescence and forward scatter measurements, respectively, after staining with the DNA‐binding dye 4′,6‐diamidino‐2′‐phenylindole, DAPI), and cell concentration, after staining with the nucleic acid binding dye LDS‐751. The strain was cultivated on a mineral medium with pyruvic acid sodium salt as the limiting carbon and energy source. Famine conditions, and thus cell dormancy, were achieved in every cycle. The best synchronization, according to the determination of DNA contents, was induced with phasing cycle durations of at least 4 h. The method allows the induction of synchrony for an indefinite period if the medium is exchanged rapidly and precisely. The results show that the time required for a complete cell cycle of Cupriavidus necator JMP 134 is independent of the chosen phasing cycle duration, provided that each process cycle lasts at least 3 h which is much longer than the time needed for a single DNA replication cycle. With shorter cycling periods DNA‐synthesis is carried out in an uncoupled manner and only weak cell cycle synchrony can be attained. The results also show that DNA‐synthesis can only be undertaken by cells when they have exceeded a critical size. © 2005 Wiley Periodicals, Inc.
Stochastic and Relaxation Processes in Argon by Measurements of Dynamic Breakdown Voltages
Authors: Marković V. Lj. , Stamenković S. N. , Gocić S. R. , Petrović Z. Lj.
Published: September 2005

Statistically based measurements of breakdown voltages U b and breakdown delay times td and their variations in transient regimes of establishment and relaxation of discharges are a convenient method to study stochastic processes of electrical breakdown of gases, as well as relaxation kinetics in afterglow. In this paper the measurements and statistical analysis of the dynamic breakdown voltages U b for linearly rising (ramp) pulses in argon at 1.33 mbar and the rates of voltage rise k up to 800 V s –1 are presented. It was found that electrical breakdowns by linearly rising (ramp) pulses is an inhomogeneous Poisson process caused by primary and secondary ionization coefficients α , γ and electron yield Y variations on the voltage (time). The experimental breakdown voltage distributions were fitted by theoretical distributions by applying approximate analytical and numerical models. The afterglow kinetics in argon was studied based on the dependence of the initial electron yield on the relaxation time Y 0 (τ ) derived from fitting of distributions. The space charge decay was explained by the surface recombination of nitrogen atoms present as impurities. The afterglow kinetics and the surface recombination coefficients on the gas tube and cathode were determined from a gas‐phase model. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Assessment of ATM phosphorylation on Ser‐1981 induced by DNA topoisomerase I and II inhibitors in relation to Ser‐139‐histone H2AX phosphorylation, cell cycle phase, and apoptosis
Authors: Kurose Akira , Tanaka Toshiki , Huang Xuan , Halicka H. Dorota , Traganos Frank , Dai Wei , Darzynkiewicz Zbigniew
Published: September 2005

Background

The ATM kinase regulates cell‐cycle checkpoints by phosphorylating multiple proteins, including histone H2AX, CHK1, and CHK2 kinases and p53. ATM is activated through auto‐ or trans‐ phosphorylation of Ser‐1981 in response to DNA damage, particularly induction of DNA double‐strand breaks (DSBs). The aim of the present study was to reveal a possible correlation between activation of ATM vis‐à‐vis H2AX phosphorylation, cell cycle phase, and apoptosis in cells treated with DNA topoisomerase (topo) I (topotecan; Tpt) or topo2 (mitoxantrone; Mtx) inhibitor.

Materials and Methods

Cultures of HL‐60 cells were treated with Tpt or Mtx for various time intervals. ATM or H2AX phosphorylation was detected immunocytochemically, using Ab specific for ATM phosphorylated on Ser‐1981 (ATM‐S1981P) or for H2AX (γH2AX) phosphorylated on Ser‐139, respectively, concurrent with the analysis of cellular DNA content. Cellular fluorescence was measured by flow cytometry.

Results

Untreated cells showed a modest but variable level of labeling with ATM‐S1981P Ab across the cell cycle, with exception of mitotic cells that were strongly labeled. Exposure of cells to 150 nM Tpt induced ATM phosphorylation concurrent with phosphorylation of H2AX within 10 min; phosphorylation of both proteins was essentially limited to S‐phase and was suppressed by caffeine and wortmannin, inhibitors of PI‐3‐like kinases. Exposure of cells to Mtx also led to ATM and H2AX phosphorylation, which, compared to Tpt, occurred later and was not cell‐cycle‐phase specific. Apoptosis of HL‐60 cells in Tpt or Mtx treated cultures was detected after 2 or 4 h, respectively, and was limited to S‐phase cells.

Conclusions

The data are consistent with the role of ATM as a mediator of H2AX phosphorylation in response to DNA damage by topo1 (Tpt) or topo 2 (Mtx) inhibitor. The observed cell‐cycle‐phase related differences in response to Tpt vs Mtx suggest that while the collisions of DNA replication forks with the “cleavable complexes” stabilized by topo1 inhibitor are the primary cause of DSBs induced by Tpt, the collisions of RNA polymerase molecules with the complexes stabilized by the topo2 inhibitor play a major role for induction of DSBs by Mtx. The present report is the first that (i) describes cytometric analysis of ATM activation and (ii) demonstrates activation of the enzyme (kinase) and its consequence (substrate phoshorylation), both in relation to cell‐cycle phase and onset of apoptosis within the same cells. © 2005 International Society for Analytical Cytology
Detection of various platelet‐associated immunoglobulins by flow cytometry in idiopathic thrombocytopenic purpura
Authors: Nishioka Takuya , Yamane Takahisa , Takubo Takayuki , Ohta Kensuke , Park Keunsik , Hino Masayuki
Published: September 2005

Background

In 1975, Dixson reported that anti‐platelet IgG on platelets from patients with idiopathic thrombocytopenic purpura (ITP) is greater than in normal people, by determining anti‐platelet antibodies directly on the platelet surface with a quantitative complement lysis–inhibition–assay. Since then, platelet‐associated IgG (PAIgG) has been thought of as evidence of ITP. Although platelets from ITP patients show significantly higher PAIgG values than from normal control individuals, PAIgG is not specific for autoantibody because it increases in other than immune ITP patients.

Methods

We analyzed positive platelet percentage with various platelet‐associated immunoglobulins: IgG, IgM, IgA, and total immunoglobulins, in the blood from 17 normal donors and 23 ITP patients.

Results

The specificity for ITP disease was better in flow cytometry than in ELISA, because, other than ITP, only aplastic anemia was positive in flow cytometry; however, various disorders (aplastic anemia, chronic lymphocytic leukemia, acute myeloid leukemia, and myelodysplastic syndrome) showed positive in ELISA. Flow cytometry methods had the same sensitivity for ITP disease as ELISA. However, it is supposed that there was no nonimmune ITP in this study because the PAIgG negative patients (n = 1) showed positive results in flow cytometry.

Conclusion

Flow cytometry method was effective for ITP screening, especially for specificity. © 2005 Wiley‐Liss, Inc.
Autoreactive human peripheral blood CD8+ T cells with a regulatory phenotype and function
Authors: Jarvis Lorna B. , Matyszak Malgosia K. , Duggleby Richard C. , Goodall Jane C. , Hall Frances C. , Gaston J. S. Hill
Published: September 2005

Despite substantial advances in our understanding of CD4+CD25+ regulatory T cells, a possible equivalent regulatory subset within the CD8+ T cell population has received less attention. We now describe novel human CD8+/TCRαβ+ T cells that have a regulatory phenotype and function. We expanded and cloned these cells using autologous LPS‐activated dendritic cells. The clones were not cytolytic, but responded in an autoreactive HLA class I‐restricted fashion, by proliferation and production of IL‐4, IL‐5, IL‐13 and TGFβ1, but not IFN‐γ. They constitutively expressed CD69 and CD25 as well as molecules associated with CD4+CD25+ regulatory T cells, including cytotoxic T lymphocyte‐associated antigen‐4 (CTLA‐4) and Foxp3. They suppressed IFN‐γ production and proliferation by CD4+ T cells in vitro in a cell contact‐dependent manner, which could be blocked using a CTLA‐4‐specific mAb. They were more readily isolated from patients with ankylosing spondylitis and may therefore be up‐regulated in response to inflammation. We suggest that they are the CD8+ counterparts of CD4+CD25+ regulatory T cells. They resemble recently described CD8+ regulatory cells in the rat that were able to abrogate graft‐versus‐host disease. Likewise, human HLA‐restricted CD8+ regulatory T cells that can be cloned and expanded in vitro may have therapeutic applications.
Control of dual‐specificity phosphatase‐1 expression in activated macrophages by IL‐10
Authors: Hammer Michael , Mages Jörg , Dietrich Harald , Schmitz Frank , Striebel Frank , Murray Peter J. , Wagner Hermann , Lang Roland
Published: September 2005

Ligation of Toll‐like receptors (TLR) on macrophages induces cytokines and mediators important for the control of pathogens. Macrophage activation has to be tightly controlled to prevent hyper‐inflammation. Accordingly, the hallmarks of TLR‐triggered signaling, nuclear translocation of NF‐κB and phosphorylation of mitogen‐activated protein kinases (MAPK), are transient events. We have mined microarray datasets for changes in the expression of phosphatases in resting and TLR‐activated macrophages. Several members of the dual‐specificity phosphatases (DUSP) were induced upon triggering TLR4 with LPS. Up‐regulation of DUSP1 mRNA was transient after stimulation with LPS alone, but addition of the immunosuppressive cytokine IL‐10 resulted in robust, continued DUSP1 expression. IL‐10 also synergized with the anti‐inflammatory glucocorticoid dexamethasone in the induction of DUSP1 mRNA expression in activated macrophages, as well as in the inhibition of IL‐6 and IL‐12 production. Increased expression of DUSP1 in IL‐10‐treated activated macrophages was correlated with a faster down‐regulation of p38 MAPK activation. Thus, these data suggest an operational link between IL‐10 and inibition of p38 MAPK via sustained expression of DUSP1.
Distinct effects of CD86‐mediated costimulation on resting versus activated human CD4+ T cells
Authors: Rogers Nicola J. , Game David S. , Camara Niels O. S. , Jackson Ian M. , Lombardi Giovanna , Lechler Robert I.
Published: September 2005

CD80 and CD86 are important in the initiation of T cell immunity. Although their costimulatory function has long been appreciated, it remains unclear whether the biological significance of the two B7 isoforms resides in their different patterns and kinetics of expression or whether differences exist in their function. We have addressed this issue using HLA‐DR1 transfectants co‐expressing CD80, CD86, or both molecules as stimulators for naïve, memory, and activated human CD4+ T cells. Both CD80 and CD86 efficiently costimulated alloresponses by unseparated peripheral blood CD4+ T cells; however, CD86 was substantially inferior in costimulating alloresponses by separated memory T cells, and completely incompetent in costimulating three human T cell clones. Furthermore, CD80/CD86 double transfectants stimulated lower responses by the clones than cells expressing CD80 alone. That CD86 was actively inhibitory rather than merely neutral was evidenced by the increase in response to the double CD80/CD86 APC when anti‐CD86 antibody was added. Furthermore, addition of anti‐CTLA‐4 Fab to cultures of HLA‐DR1 transfectants co‐expressing CD86, fully restored the proliferative response. These results indicate that CD80 and CD86 mediate distinct signals in previously activated T cells, and demonstrate that CTLA‐4 ligation may dominate the outcome of CD86‐mediated costimulation of activated CD4+ T cells.
IgG Fc receptor polymorphisms and association with autoimmune disease
Authors: Andrén Maria , Johanneson Bo , Alarcón‐Riquelme Marta E. , Kleinau Sandra
Published: September 2005

The aim of this study was to investigate whether a genetic polymorphism of FcγRIII exists in mice, which could explain the different susceptibility to pathogenic IgG anti‐collagen type II (CII) antibodies in mice carrying the collagen‐induced arthritis (CIA)‐susceptible H‐2q haplotype. The gene for FcγRIII was sequenced in 11 common mouse strains, and the results revealed three different haplotypes of mouse FcγRIII: FcγRIII:V, FcγRIII:H and FcγRIII:T. To study the consequences of this polymorphism, we generated mice carrying the FcγRIII:H haplotype from the CIA‐susceptible, H‐2q‐positive DBA/1 mouse or the FcγRIII:V haplotype from the CIA‐resistant, H‐2q‐positive SWR mouse. After CII immunization or transfer of IgG anti‐CII antibodies, FcγRIII:H‐expressing mice, but not FcγRIII:V‐expressing mice, developed progressively severe arthritis. We also investigated if C5, in addition to FcγRIII polymorphism, could affect the susceptibility to the pathogenic IgG anti‐CII antibodies in H‐2q‐positive mice. Here we show that SWR mice, naturally deficient in C5, can develop CIA when supplemented with C5 and that anti‐C5 antibody treatment of FcγRIII:H‐expressing mice inhibits arthritis development. These data demonstrate for the first time a genetic polymorphism of FcγRIII in mice that may, together with C5, regulate induction of autoimmune disease.
α‐Galactosylceramide‐induced iNKT cells suppress experimental allergic asthma in sensitized mice: Role of IFN‐γ
Authors: Hachem Patricia , Lisbonne Mariette , Michel Marie‐Laure , Diem Séverine , Roongapinun Sukit , Lefort Jean , Marchal Gilles , Herbelin André , Askenase Philip W. , Dy Michel , Leite‐de‐Moraes Maria C.
Published: September 2005

Allergic asthma is a multifaceted syndrome consisting of eosinophil‐rich airway inflammation, bronchospasm, and airway hyper‐responsiveness (AHR). Using a mouse model of allergic asthma, we previously reported that invariant NKT (iNKT) cells increase the severity of this disease. Herein, we demonstrate that a single i.v. injection of α‐galactosylceramide (α‐GalCer), 1 h before the first airway allergen challenge of OVA‐sensitized mice, abrogates elicitation of AHR, airway eosinophilia, IL‐4 and IL‐5 production in bronchoalveolar lavage fluid, and specific anti‐OVA IgE antibodies. Further, α‐GalCer administered intranasally also strongly inhibited the major symptoms of asthma in sensitized and challenged mice. α‐GalCer treatment induces iNKT cell accumulation in the lungs, and shifts their cytokine profile from pro‐asthmatic IL‐4 to a protective IFN‐γ production. The role of IFN‐γ from iNKT cells in protection was shown by adoptive transfer of sorted iNKT cells from OVA‐sensitized and α‐GalCer‐treated mice which protected immunized recipients from manifesting asthma by an IFN‐γ‐dependent pathway. Our findings demonstrate for the first time that α‐GalCer administered locally inhibits asthma symptoms, even in predisposed asthmatic mice, through an iNKT cell‐ and IFN‐γ‐dependent pathway.

See accompanying commentary: http://dx.doi.org/10.1002/eji.200535425
Splenic marginal zone B cells in humans: Where do they mutate their Ig receptor?
Authors: Weller Sandra , Reynaud Claude‐Agnès , Weill Jean‐Claude
Published: September 2005

Human IgM+IgD+CD27+ B cells have mutated Ig genes and harbor a splenic marginal zone (MZ) phenotype. In this issue, the group of R. Küppers has studied the expression of the enzyme activation‐induced cytidine deaminase (AID) in human spleen samples by immunocytochemistry and failed to detect a significant AID‐expressing subset in the MZ region. The consequences on the possible origin of these cells are discussed.

See accompanying article: http://dx.doi.org/10.1002/eji.200535134
Mössbauer Investigation of Peroxo Species in the Iron(III)–EDTA–H2O2 System
Authors: Sharma Virender K. , Szilágyi Petra Á. , Homonnay Zoltán , Kuzmann Ernő , Vértes Attila
Published: September 2005

The reaction of a diiron(III)–EDTA complex with H2O2 in alkaline medium is studied by Mössbauer spectroscopy in conjunction with the rapid‐freeze/quench technique in order to identify possible intermediate species during the formation and decomposition of the purple (EDTA)FeIII(η2‐O2)3– complex ion. Starting from the six‐coordinate [FeIIIEDTA]– species at acidic pH, it is demonstrated that mononuclear complexes formed at a pH of about 1 are convert into the diiron(III)–EDTA complex [(EDTA)FeIII‐O‐FeIII(EDTA)]4– upon raising the pH to around 10.4. H2O2 reacts with the diiron(III) complex to give peroxide/hydroperoxide related adducts. Initially, the reaction tears apart the dimers to form a peroxo adduct, namely the seven‐coordinate mononuclear [(EDTA)FeIII(η2‐O2)]3–, which is stable only at very high pH. The decomposition of this peroxo adduct gives two new species, which are reported for the first time. The Mössbauer parameters of these species suggest a six‐coordinate μ‐peroxodiiron(III) complex [(EDTA)FeIII‐(OO)‐FeIII(EDTA)]4– and a seven‐coordinate μ‐hydroxo‐μ‐peroxodiiron(III) complex [(EDTA)FeIII‐(OO)(OH)‐FeIII(EDTA)]5–. A badly resolved, extremely broad component is observed in the Mössbauer spectra during the conversion of the monomer to dimeric peroxo species, which may be attributed to the short‐lived [(EDTA)FeIII‐OO]3– or [(EDTA)FeIII‐OOH]2– intermediate species. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Generation and Reactions of Overcrowded Diaryldilithiostannane and Diaryldipotassiostannane
Authors: Tajima Tomoyuki , Takeda Nobuhiro , Sasamori Takahiro , Tokitoh Norihiro
Published: September 2005

Exhaustive reduction of an overcrowded dibromostannane bearing two bulky aromatic substituents, Tbt(Dip)SnBr2 {Tbt = 2,4,6‐tris[bis(trimethylsilyl)methyl]phenyl; Dip = 2,6‐diisopropylphenyl}, with an excess amount of lithium naphthalenide in THF at –78 °C gave the corresponding dilithiostannane, Tbt(Dip)SnLi2, the generation of which was confirmed by trapping experiments with some electrophiles together with 119Sn and 7Li NMR spectroscopy. The diaryldilithiostannane was found to be stable in solution under an inert gas below –25 °C. The potassium analogue, Tbt(Dip)SnK2, was also generated by the reduction of the dibromostannane in THF at –78 °C by the use of KC8 as a reductant. The reactions of dilithiostannane and dipotassiostannane obtained with o‐dibromobenzene did not give a stannacyclopropabenzene derivative but an unexpected cyclization product, a stannacyclobutabenzene derivative, in contrast to thereactions of the corresponding dilithiosilane and dilithiogermane, Tbt(Dip)ELi2 (E = Si, Ge), with o‐dibromobenzene leading to the formation of the corresponding metallacyclopropabenzenes as stable crystalline compounds. A preliminary result of the synthesis of a tin–tellurium double‐bond compound from the dilithiostannane is also presented. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthetic Routes to the Encapsulation of II–VI Semiconductors in Mesoporous Hosts
Authors: Turner Elizabeth A. , Huang Yining , Corrigan John F.
Published: September 2005

Ordered mesoporous silicate materials, such as MCM‐41 and SBA‐15, offer a nanometre‐sized environment for the inclusion of quantum‐confined materials. The channel walls of the framework hinder cluster‐cluster interactions thereby restricting particle growth and thus limiting the size of the enclosed particles to the nanometre‐size regime. In particular, the past decade has seen substantial progress in the synthesis and encapsulation of II–VI nanoparticles within MCM‐41 and SBA‐15. This microreview highlights the recent developments in this area, with notable emphasis on the synthetic routes used in the growth and anchoring of CdS, CdSe and ZnS nanoparticles within a mesoporous host. Of relevance are the methods of ion‐exchange, interior pore wall modification, quantum‐dot doping, incorporation of preformed nanoparticles and clusters and external surface passivation through organic functionalization. In addition to synthetic methods employed, the interesting photochemical properties of the composite materials are discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthesis and Absolute Configuration of 6‐Hydroxylated New Ceramides in Human Skin, Ceramides B, 4, 7 and 8
Authors: Masuda Yui , Mori Kenji
Published: September 2005

6R‐Configuration was assigned to three new ceramides isolated from human skin such as ceramide B [1, (2S,3R,4E,6R)‐6‐hydroxy‐N‐(30′‐hydroxytriacontanoyl)‐4‐sphingenine], ceramide 8 [2, (2S,3R,4E,6R)‐6‐hydroxy‐N‐(tetracosanoyl)‐4‐sphingenine] and ceramide 4 {3, (2S,3R,4E,6R)‐6‐hydroxy‐N‐[(30′‐linoleoyloxy)triacontanoyl]‐4‐sphingenine}. (6R,2′R)‐Configuration was given to another ceramide in human skin, ceramide 7 [4, (2S,3R,4E,6R,2′R)‐6‐hydroxy‐N‐(2′‐hydroxytetracosanoyl)‐4‐sphingenine]. These assignments were made possible by enzymatic preparation of the enantiomers of 1‐pentadecyn‐3‐ol and those of 2‐hydroxytetracosanoic acid. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Utility of Azolium Triflates as Promoters for the Condensation of a Nucleoside Phosphoramidite and a Nucleoside in the Agrawal's Stereoselective Synthesis of Nucleoside Phosphorothioates
Authors: Hyodo Mamoru , Ando Hirotaka , Nishitani Hisashi , Hattori Akira , Hayakawa Hiroyuki , Kataoka Masanori , Hayakawa Yoshihiro
Published: September 2005

This paper demonstrates that some azolium triflates, such as N‐phenylimidazolium triflate, benzimidazolium triflate and N‐methylbenzimidazolium triflate, are more useful than 1H‐tetrazole as promoters for the stereoselective condensation of a 5′‐O‐free nucleoside and a stereochemically pure 5′‐O‐(p,p′‐dimethoxytrityl)‐3′‐O‐{(4R)‐1H,3H‐pyrrolo[1,2‐c]‐1,3,2‐oxazaphospholidin}‐2‐yl 2′‐deoxyribonucleoside (Rc‐1) or 5′‐O‐(p,p′‐dimethoxytrityl)‐3′‐O‐{(4S)‐1H,3H‐pyrrolo[1,2‐c]‐1,3,2‐oxazaphospholidin}‐2‐yl 2′‐deoxyribonucleoside (Sc‐2) (Agrawal strategy). The azolium triflates allowed the stereoselective formation of an internucleotide phosphorothioate bond via the above‐described condensation using a stereochemically pure phosphoramidite, followed by sulfurization using bis[3‐triethoxysilylpropyl]tetrasulfide. The highest diastereoexcess values of the products in the synthesis of dideoxyribonucleoside phosphorothioates using a suitable azolium triflate such as benzimidazolium triflate, N‐methylbenzimidazolium triflate or N‐phenylimidazolium triflate were 90–96 % in solution phase or 80–88 % in solid phase; these values were higher than those obtained in the synthesis using 1H‐tetrazole as a promoter for the condensation of a nucleoside phosphoramidite and a nucleoside. This paper also describes that studies on the absolute configurations of stereogenic phosphorus atoms in the phosphoramidites Rc‐1 and Sc‐2 by meansof two different existing methods, i. e., the Beaucage method, gave contrary conclusions, and thus the configurations should be determined by an absolutely reliable method, such as X‐ray analysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Towards Immunoproteasome‐Specific Inhibitors: An Improved Synthesis of Dihydroeponemycin
Authors: Ho Abby , Cyrus Kedra , Kim Kyung‐Bo
Published: September 2005

Eponemycin, an antitumor and antiangiogenic epoxy ketone natural product, is previously shown to target proteasome for its activity. Although there have been many synthetic approaches developed, practical and efficient synthetic strategy for eponemycin has yet to be accomplished. Here, we report an efficient new route for the preparation of dihydroeponemycin, an active eponemycin derivative. This will aid the design of proteasome inhibitors with novel activity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Regulation of the Atm promoter in vivo
Authors: Gueven Nuri , Fukao Toshiyuki , Luff John , Paterson Carol , Kay Graham , Kondo Naomi , Lavin Martin F.
Published: September 2005

While ATM, the protein defective in the human genetic disorder ataxia‐telangiectasia (A‐T), is primarily activated as a preexisting protein by radiation, there is also evidence that expression of the protein can be regulated at the transcriptional level. Activation of the ATM promoter by ionizing radiation has been reported only in quiescent cells in culture. To investigate how the Atm promoter is regulated in vivo, we generated transgenic mice that express the luciferase reporter gene under the control of the murine Atm promoter. Using a biophotonic imaging system luciferase activity was monitored in vivo. Strong promoter activity was detected throughout the transgenic animals with particularly high signals from the thymus, abdominal region, and reproductive organs. This activity further increased in response to both ionizing radiation and heat stress in a time dependent manner. Luciferase activity, measured in vitro in extracts from different tissues, showed highest activities in testes, ovaries, and cerebellum. Subjecting these mice to a single dose of 4 Gy total body radiation led to a time‐dependent activation of the promoter with the strongest response observed in the peritoneal membrane, skin, and spleen. For most tissues tested, maximal promoter activity was reached 8 hr after radiation. The observed changes in promoter activity largely correlated with levels and activity of Atm protein in tissue extracts. These results demonstrate that, in addition to activation by autophosphorylation, Atm can also be regulated in vivo at the transcriptional level possibly ensuring a more sustained response to radiation and other stimuli. © 2005 Wiley‐Liss, Inc.
Effect of pneumatic power tool use on nerve conduction velocity across the wrist
Authors: Rosecrance John , Anton Dan , Cook Thomas , Merlino Linda
Published: September 2005

The purpose of this study was to determine if the use of pneumatic power tools altered electrophysiologic properties of the median and ulnar nerves at the wrist during the work shift. Sensory nerve conduction velocities were measured in hands of workers before work and then at 2‐hour intervals during the workday. Ten workers exposed to pneumatic power tool use and 10 workers not exposed to intensive hand activity were evaluated. The conduction velocities slowed significantly across the wrist in the median and ulnar nerves among workers using pneumatic tools but not among control workers. This investigation demonstrated that short‐term exposure to highly intensive hand tasks causes significant slowing in nerve conduction velocity across the wrist. © 2005 Wiley Periodicals, Inc. Hum Factors Man 15: 339–352, 2005.