bluuebunny/crossref_metadata_2025 huggingface dataset:
Suppression of Regulatory T Cells by IL-12p40 Homodimer via Nitric Oxide
Authors: Brahmachari Saurav , Pahan Kalipada
Published: July 2009

Regulatory T cells (Tregs) play a pivotal role in the maintenance of homeostasis between immune response and immune tolerance. The transcription factor Foxp3 and the surface protein CD25 are the two key molecules characterizing Tregs. In autoimmune and various other chronic inflammatory diseases, the expression of Foxp3 is severely down-regulated. However, the molecular mechanism underlying the down-regulation of Foxp3 is not understood yet. Because the IL-12p40 homodimer (p402) is markedly up-regulated in response to various inflammatory stimuli, the present study was undertaken to explore the role of p402 in the regulation of Foxp3 in naive mouse splenocytes. IL-12p402 dose-dependently inhibited the expression of Foxp3 and CD25, but not CD4. Interestingly, this inhibition was absent in splenocytes of IL-12Rβ1−/−, but not IL-12Rβ2−/−, mice. Moreover, suppression of Foxp3 in wild-type and IL-12Rβ2−/− splenocytes was accompanied by production of NO. Consistently, l-N6-(1-iminoethyl)-lysine hydrochloride, an inhibitor of inducible NO synthase (iNOS), and PTIO, a scavenger of NO, restored the expression of Foxp3 and CD25 in p402-stimulated splenocytes, and p402 was unable to down-regulate Foxp3 and CD25 in splenocytes from iNOS−/− mice. Furthermore, NO, but not p402, was able to inhibit Foxp3 in purified CD4+CD25+ T cells in the absence of iNOS-expressing cells. Hence, our results clearly demonstrate that p402 induces NO production via IL-12Rβ1 and that NO subsequently suppresses Tregs in naive mouse splenocytes. This study, therefore, delineates an unprecedented biological function of p402 in the regulation of Foxp3 via IL-12Rβ1-mediated NO production.
STAT1 Negatively Regulates Lung Basophil IL-4 Expression Induced by Respiratory Syncytial Virus Infection
Authors: Moore Martin L. , Newcomb Dawn C. , Parekh Vrajesh V. , Van Kaer Luc , Collins Robert D. , Zhou Weisong , Goleniewska Kasia , Chi Michael H. , Mitchell Daphne , Boyce Joshua A. , Durbin Joan E. , Sturkie Carla , Peebles R. Stokes
Published: July 2009

IL-4 contributes to immunopathology induced in mice by primary respiratory syncytial virus (RSV) infection. However, the cellular source of IL-4 in RSV infection is unknown. We identified CD3−CD49b+ cells as the predominant source of IL-4 in the lungs of RSV-infected BALB/c mice. We ruled out T cells, NK cells, NKT cells, mast cells, and eosinophils as IL-4 expressors in RSV infection by flow cytometry. Using IL4 GFP reporter mice (4get) mice, we identified the IL-4-expressing cells in RSV infection as basophils (CD3−CD49b+FcεRI+c-kit−). Because STAT1−/− mice have an enhanced Th2-type response to RSV infection, we also sought to determine the cellular source and role of IL-4 in RSV-infected STAT1−/− mice. RSV infection resulted in significantly more IL-4-expressing CD3−CD49b+ cells in the lungs of STAT1−/− mice than in BALB/c mice. CD49b+IL-4+ cells sorted from the lungs of RSV-infected STAT1−/− mice and stained with Wright-Giemsa had basophil characteristics. As in wild-type BALB/c mice, IL-4 contributed to lung histopathology in RSV-infected STAT1−/− mice. Depletion of basophils in RSV-infected STAT1−/− mice reduced lung IL-4 expression. Thus, we show for the first time that a respiratory virus (RSV) induced basophil accumulation in vivo. Basophils were the primary source of IL-4 in the lung in RSV infection, and STAT1 was a negative regulator of virus-induced basophil IL-4 expression.
Infection with a Helminth Parasite Attenuates Autoimmunity through TGF-β-Mediated Suppression of Th17 and Th1 Responses
Authors: Walsh Kevin P. , Brady Miriam T. , Finlay Conor M. , Boon Louis , Mills Kingston H. G.
Published: July 2009

The lower incidence of allergy and autoimmune diseases in developing countries has been associated with a high prevalence of parasitic infections. Here we provide direct experimental evidence that parasites can exert bystander immunosuppression of pathogenic T cells that mediate autoimmune diseases. Infection of mice with Fasciola hepatica resulted in recruitment of dendritic cells, macrophages, eosinophils, neutrophils, and CD4+ T cells into the peritoneal cavity. The dendritic cells and macrophages in infected mice expressed IL-10 and latency-associated peptide, and they had low surface expression of costimulatory molecules and/or MHC class II. Furthermore, most CD4+ T cells in the peritoneal cavity of infected mice secreted IL-10, but not IFN-γ or IL-4. There was a less significant expansion of CD4+Foxp3+ T cells. F. hepatica-specific Tr1-type clones generated from infected mice suppressed proliferation and IFN-γ production by Th1 cells. Infection was associated with suppression of parasite-specific Th1 and Th2 responses, which was reversed in IL-10-defective mice. Infection with F. hepatica also exerted bystander suppression of immune responses to autoantigens and attenuated the clinical signs of experimental autoimmune encephalomyelitis. Protection was associated with suppression of autoantigen-specific IFN-γ and IL-17 production. The suppression of Th1 and Th17 responses and attenuation of experimental autoimmune encephalomyelitis by F. hepatica was maintained in IL-10−/− mice but was reversed by neutralization of TGF-β in vivo. Our study provides evidence that F. hepatica-induced IL-10 subverts parasite-specific Th1 and Th2 responses, but that F. hepatica-induced TGF-β plays a critical role in bystander suppression of autoantigen-specific Th1 and Th17 responses that mediate autoimmune diseases.
NLRP3 (NALP3, Cryopyrin) Facilitates In Vivo Caspase-1 Activation, Necrosis, and HMGB1 Release via Inflammasome-Dependent and -Independent Pathways
Authors: Willingham Stephen B. , Allen Irving C. , Bergstralh Daniel T. , Brickey Willie June , Huang Max Tze-Han , Taxman Debra J. , Duncan Joseph A. , Ting Jenny P.-Y.
Published: July 2009

Bacterial infection elicits a range of beneficial as well as detrimental host inflammatory responses. Key among these responses are macrophage/monocyte necrosis, release of the proinflammatory factor high-mobility group box 1 protein (HMGB1), and induction of the cytokine IL-1. Although the control of IL-1β has been well studied, processes that control macrophage cell death and HMGB1 release in animals are poorly understood. This study uses Klebsiella pneumonia as a model organism because it elicits all three responses in vivo. The regulation of these responses is studied in the context of the inflammasome components NLRP3 and ASC, which are important for caspase-1 activation and IL-1β release. Using a pulmonary infection model that reflects human infection, we show that K. pneumonia-induced mouse macrophage necrosis, HMGB1, and IL-1β release are dependent on NLRP3 and ASC. K. pneumoniae infection of mice lacking Nlrp3 results in decreased lung inflammation and reduced survival relative to control, indicating the overall protective role of this gene. Macrophage/monocyte necrosis and HMGB1 release are controlled independently of caspase-1, suggesting that the former two responses are separable from inflammasome-associated functions. These results provide critical in vivo validation that the physiologic role of NLRP3 and ASC is not limited to inflammasome formation.
Late Endosome/Lysosome-Localized Rab7b Suppresses TLR9-Initiated Proinflammatory Cytokine and Type I IFN Production in Macrophages
Authors: Yao Ming , Liu Xingguang , Li Dong , Chen Taoyong , Cai Zhen , Cao Xuetao
Published: July 2009

Inappropriate activation of TLR9 has been found to be involved in the pathogenesis of autoimmune diseases such as systemic lupus erythematosus. TLR9 antagonists have been proposed to be therapeutic for some kinds of autoimmune diseases. In contrast, new negative regulators of TLR9 signal pathway need to be identified, and the mechanisms for the control of TLR9 response need to be fully investigated. It is well known that TLR9 will be finally transported to late endosome/lysosome once activated; however, the exact mechanism and the biological significance of the redistribution have not been fully elucidated. Ras related in brain (Rab)7b is a small guanosine triphosphatase, identified by us before, which is mainly localized in late endosome/lysosome. Our previous study shows that Rab7b can negatively regulate TLR4 signaling by promoting lysosomal degradation of TLR4. In this study, we show that TLR9 ligation can inhibit Rab7b expression in macrophages via ERK and p38 activation. In turn, the late endosome/lysosome-localized Rab7b can colocalize with TLR9 in lysosomal-associated membrane protein 1-positive compartment and down-regulate the expression of the TLR9 in macrophages by promoting TLR9 degradation once TLR9 is activated. Accordingly, Rab7b can negatively regulate TLR9-triggered production of TNF-α, IL-6, and IFN-β in macrophages by impairing activation of MAPKs and NF-κB pathways. Our results suggest that the late endosome/lysosome-localized Rab7b can down-regulate TLR9-triggered proinflammatory cytokine and type I IFN production by impairing TLR9 signaling via promotion of TLR9 degradation.
Tissue-Specific Abundance of Regulatory T Cells Correlates with CD8+ T Cell Dysfunction and Chronic Retrovirus Loads
Authors: Myers Lara , Messer Ronald J. , Carmody Aaron B. , Hasenkrug Kim J.
Published: July 2009

Infection of mice with Friend virus induces the activation of CD4+ regulatory T cells (Tregs) that suppress virus-specific CD8+ T cells. This suppression leads to incomplete virus clearance and the establishment of virus persistence. We now show that Treg-mediated suppression of CD8+ T cells is tissue specific, occurring in the spleen but not the liver. Regardless of infection status, there was a 5-fold lower proportion of Tregs in the liver than in the spleen, much lower absolute cell numbers, and the relatively few Tregs present expressed less CD25. Results indicated that reduced expression of CD25 on liver Tregs was due to microenvironmental factors including low levels of IL-2 production by CD4+ Th cells in that tissue. Low CD25 expression on liver Tregs did not impair their ability to suppress CD8+ T cells in vitro. Correlating with the decreased proportion of Tregs in the liver was a significantly increased proportion of virus-specific CD8+ T cells compared with the spleen. The virus-specific CD8+ T cells from the liver did not appear suppressed given that they produced both IFN-γ and granzyme B, and they also showed evidence of recent cytolytic activity (CD107a+). The functional phenotype of the virus-specific CD8+ T cells correlated with a 10-fold reduction of chronic Friend virus levels in the liver compared with the spleen. Thus, suppression of CD8+ T cells by virus-induced Tregs occurs in a tissue-specific manner and correlates with profound effects on localized levels of chronic infection.
A Critical Role for REV1 in Regulating the Induction of C:G Transitions and A:T Mutations during Ig Gene Hypermutation
Authors: Masuda Keiji , Ouchida Rika , Li Yingqian , Gao Xiang , Mori Hiromi , Wang Ji-Yang
Published: July 2009

REV1 is a deoxycytidyl transferase that catalyzes the incorporation of deoxycytidines opposite deoxyguanines and abasic sites. To explore the role of its catalytic activity in Ig gene hypermutation in mammalian cells, we have generated mice expressing a catalytically inactive REV1 (REV1AA). REV1AA mice developed normally and were fertile on a pure C57BL/6 genetic background. B and T cell development and maturation were not affected, and REV1AA B cells underwent normal activation and class switch recombination. Analysis of Ig gene hypermutation in REV1AA mice revealed a great decrease of C to G and G to C transversions, consistent with the disruption of its deoxycytidyl transferase activity. Intriguingly, REV1AA mice also exhibited a significant reduction of C to T and G to A transitions. Moreover, each type of nucleotide substitutions at A:T base pairs was uniformly reduced in REV1AA mice, a phenotype similar to that observed in mice haploinsufficient for Polh. These results reveal an unexpected role for REV1 in the generation of C:G transitions and A:T mutations and suggest that REV1 is involved in multiple mutagenic pathways through functional interaction with other polymerases during the hypermutation process.
The CCL7-CCL2-CCR2 Axis Regulates IL-4 Production in Lungs and Fungal Immunity
Authors: Szymczak Wendy A. , Deepe George S.
Published: July 2009

Expression of the chemokine receptor CCR2 can be detrimental or beneficial for infection resolution. Herein, we examined whether CCR2 was requisite for control of infection by the dimorphic fungus Histoplasma capsulatum. H. capsulatum-infected CCR2−/− mice manifested defects in inflammatory cell recruitment, increased IL-4, and progressive infection. Increased IL-4 in CCR2−/− mice primarily contributed to decreased host resistance as demonstrated by the ability of IL-4-neutralized CCR2−/− mice to resolve infection without altering inflammatory cell recruitment. Surprisingly, numerous alveolar macrophages and dendritic cells contributed to IL-4 production in CCR2−/− mice. IL-4-mediated impairment of immunity in CCR2−/− mice was associated with increased arginase-1 and YM1 transcription and increased transferrin receptor expression by phagocytic cells. Immunity in mice lacking the CCR2 ligand CCL2 was not impaired despite decreased inflammatory cell recruitment. Neutralization of the CCR2 ligand CCL7 in CCL2−/− mice, but not wild type, resulted in increased IL-4 and fungal burden. Thus, CCL7 in combination with CCL2 limits IL-4 generation and exerts control of host resistance. Furthermore, increased phagocyte-derived IL-4 in CCR2−/− mice is associated with the presence of alternatively activated phagocytic cells.
Unprecedent Chemo‐ and Stereoselective Palladium‐Catalysed Methoxycarbonylation of Norbornene
Authors: Blanco Carolina , Ruiz Aurora , Godard Cyril , Fleury‐Brégeot Nicolas , Marinetti Angela , Claver Carmen
Published: July 2009

Catalytic systems able to control chemo‐ and stereoselectivity have been tested in the palladium‐catalysed methoxycarbonylation of norbornene. An enantioselectivity of up to 40% was obtained.
Lanthanide Bis[(trifluoromethyl)sulfonyl]imides as Reusable Catalysts for Mononitration of Substituted Benzenes in Ionic Liquids
Authors: Wang Shuojin , Jiang Shaojie , Nie Jin
Published: July 2009

Lanthanide bis[(trifluoromethyl)sulfonyl]imides as a kind of effective catalyst were used in quaternary ammonium ionic liquids to afford a useful new method for the nitration of substituted benzenes with concentrated nitric acid (95%) as nitrating agent. The less expensive lanthanum bis[(trifluoromethyl)sulfonyl]imide was found to be the most effective catalyst employed in the ionic liquid tributylammonium bis[(trifluoromethyl)sulfonyl]imide. The lanthanum bis[(trifluoromethyl)sulfonyl]imide/tributylammonium bis[(trifluoromethyl)sulfonyl]imide system demonstrated high catalytic activity for the nitration of halobenzenes and rendered good to excellent yields. This catalyst/ionic liquid system could be recovered by simple procedures and recycled for at least 5 times.
Reactivation of spent Pd/AC catalyst by supercritical CO2fluid extraction
Authors: Zhang Xiaoxin , Zong Baoning , Qiao Minghua
Published: July 2009

In this article, we reported a nondestructive and environmentally friendly method for the reactivation of a spent Pd/AC catalyst for the hydrogenation of benzoic acid by using supercritical CO2(scCO2) fluid extraction. The effects of reactivation conditions, such as extraction temperature, pressure, CO2flow rate, and time, on the activity of the reactivated Pd/AC catalyst, were presented. The catalyst was characterized by N2physisorption, laser particle size analysis, and transmission electron spectroscopy, and the liquid extract was analyzed by GC‐MS. It is found that scCO2fluid extraction was very efficient in eliminating organic substances blocking the pores of the catalyst, while did not affect noticeably the granule size of the catalyst and the particle size of Pd. The reactivated Pd/AC catalyst regained more than 70% of the activity of the fresh 5.0 wt % Pd/AC catalyst, and has been successfully used in an industrial unit for the hydrogenation of benzoic acid. © 2009 American Institute of Chemical Engineers AIChE J, 2009
Multimodal microglia imaging of fiber tracts in acute subcortical stroke
Authors: Radlinska Basia A. , Ghinani Sasan A. , Lyon Paul , Jolly Dean , Soucy Jean‐Paul , Minuk Jeffrey , Schirrmacher Ralf , Thiel Alexander
Published: July 2009

Objective

Case series with11C‐PK11195 and positron emission tomography (PET) in stroke patients suggest that activated microglia may be detected in remote brain regions with fiber tract connections to the lesion site as an indicator of poststroke neuroinflammation. However, the specificity of these imaging findings remains to be demonstrated.

Methods

In a prospective controlled study, we measured microglia activity using11C‐PK11195‐PET along the pyramidal tract, as defined by diffusion tensor imaging, in 21 patients with first‐time acute subcortical ischemia within 2 weeks of stroke. Uptake ratios (affected vs unaffected side) were determined for a set of standardized volumes of interest along the pyramidal tracts (PT). Uptake ratios from patients in whom the PT was affected were compared with those in whom the PT was not affected. Uptake ratios were related to motor deficit and lesion size according to correlation analyses.

Results

Increased uptake ratios were only found in patients in whom the PT was affected by stroke. In the affected hemisphere, uptake was increased at the level of pons, midbrain, and internal capsule, but not in the oval center. The extent of remote microglia activation was independent of infarct size or clinical measures of stroke severity.

Interpretation

A specific activation of microglia was only found in patients in whom the PT was affected by the stroke and only caudal (anterograde) to the lesion; no activation was found in the retrograde direction or in those patients in whom the PT was not affected. These findings were independent of infarct size and may represent changes secondary to early Wallerian degeneration. Ann Neurol 2009;66:825–832
Acute hyperglycemia produces transient improvement in glucose transporter type 1 deficiency
Authors: Akman Cigdem I. , Engelstad Kristin , Hinton Veronica J. , Ullner Paivi , Koenigsberger Dorcas , Leary Linda , Wang Dong , De Vivo Darryl C.
Published: July 2009

Objective

Glucose transporter type 1 deficiency syndrome (Glut1‐DS) is characterized clinically by acquired microcephaly, infantile‐onset seizures, psychomotor retardation, choreoathetosis, dystonia, and ataxia. The laboratory signature is hypoglycorrhachia. The 5‐hour oral glucose tolerance test (OGTT) was performed to assess cerebral function and systemic carbohydrate homeostasis during acute hyperglycemia, in the knowledge that GLUT1 is constitutively expressed ubiquitously and upregulated in the brain.

Methods

Thirteen Glut1‐DS patients completed a 5‐hour OGTT. Six patients had prolonged electroencephalographic (EEG)/video monitoring, 10 patients had plasma glucose and serum insulin measurements, and 5 patients had repeated measures of attention, memory, fine motor coordination, and well‐being. All patients had a full neuropsychological battery prior to OGTT.

Results

The glycemic profile and insulin response during the OGTT were normal. Following the glucose load, transient improvement of clinical seizures and EEG findings were observed, with the most significant improvement beginning within the first 30 minutes and continuing for 180 minutes. Thereafter, clinical seizures returned, and EEG findings worsened. Additionally, transient improvement in attention, fine motor coordination, and reported well‐being were observed without any change in memory performance.

Interpretation

This study documents transient neurological improvement in Glut1‐DS patients following acute hyperglycemia, associated with improved fine motor coordination and attention. Also, systemic carbohydrate homeostasis was normal, despite GLUT1 haploinsufficiency, confirming the specific role of GLUT1 as the transporter of metabolic fuel across the blood‐brain barrier. The transient improvement in brain function underscores the rate‐limiting role of glucose transport and the critical minute‐to‐minute dependence of cerebral function on fuel availability for energy metabolism. ANN NEUROL 2010;67:31–40
Dynamic cure kinetics of epoxy–novolac compounds as studied by differential scanning calorimetry
Authors: Yang Shin‐Shiao , Hsieh Tar‐Hwa , Bi Hsiaotao T , Ho Ko‐Shan , Ho Tsung‐Han , Chen Ho‐Ruei , Ye Shi‐Hao , Chang Yu‐Chen
Published: July 2009

The cure kinetics of epoxy–novolac compounds were studied by means of differential scanning calorimetry with a dynamic approach. On the basis of a modified version of our previously reported kinetic model, a procedure aiming at the phenomenological description of the cure kinetics was developed. The reactions were found to be autocatalytic in nature for both commercial epoxy–novolac molding compounds and silica‐free imidazole‐cured epoxy–novolac systems. The weak extent of autocatalysis in the epoxy–novolac molding compounds was likely due to their high content of silica fillers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis of guar‐gum‐stabilized nanosized silver clusters with γ radiation
Authors: Biswal Jayashree , Ramnani S. P. , Shirolikar Seema , Sabharwal S.
Published: July 2009

Gamma ray induced synthesis of Ag clusters in the aqueous medium has been carried out using natural polysaccharide guar gum as a stabilizer. The results showed that guar gum is very effective in binding the Ag clusters and restricts their size in the nano region. The surface plasmon resonance band in the wavelength range of 410–425 nm of visible region has confirmed the formation of Ag clusters. The size of the clusters is governed by the concentration of both, i.e. precursor Ag+ and guar gum. The clusters were characterized by TEM and XRD, which shows that the size of clusters is in the range of 10–30 nm. The results have shown that silver clusters stabilized by guar gum are stable in acid media and alkaline media is not a desired media for the synthesis. From thermogravimetric analysis it has been demonstrated that incorporation of nano sized Ag clusters within guar gum improves the thermal properties of irradiated guar gum. To the best of our knowledge, the use of guar gum as a stabilizer in the gamma ray induced synthesis of Ag nano clusters is being reported first time in the literature. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Physical properties of water‐blown rigid polyurethane foams containing epoxidized soybean oil in different isocyanate indices
Authors: Tu Yuan‐Chan , Fan Hongyu , Suppes Galen J. , Hsieh Fu‐Hung
Published: July 2009

To explore the potential of isocyanate usage reduction, water‐blown rigid polyurethane foams were made by replacing 0, 20, and 50% of Voranoll® 490 in the B‐side of the foam formulation by epoxidized soybean oil (ESBO) with an isocyanate index ranging from 50 to 110. The compressive strength, density, and thermal conductivity of foams were measured. The foam surface temperature was monitored before and throughout the foaming reaction as an indirect indication of the foaming temperature. Increasing ESBO replacement and/or decreasing isocyanate index decreased the foam's compressive strength. The density of the foam decreased while decreasing the isocyanate index to 60. Further decrease in isocyanate index resulted in foam shrinkage causing a sharp increase in the foam density. The thermal conductivity of foams increased while decreasing the isocyanate index and increasing the ESBO replacement. Mathematical models for predicting rigid polyurethane foam density, compressive strength, and thermal conductivity were established and validated. Similar to compressive strength, the foaming temperature decreased while decreasing the isocyanate index and increasing the ESBO replacement. Because of the lower reactivity of ESBO with isocyanate, the rate of foaming temperature decrease with decreasing isocyanate index was in the order of 0% > 20% > 50% ESBO replacement. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Damping behavior of wood filled polypropylene composites
Authors: Chauhan Shakti , Karmarkar Ajay , Aggarwal Pankaj
Published: July 2009

The damping coefficient (tanδ) of wood flour filled polypropylene composites, having varying filler concentrations were measured using the free vibration decay of disk‐shaped specimen, vibrating in flexural vibration mode. The damping coefficients decreased with the increase of filler load in composites. There was no significant difference in damping behavior of composites with and without compatiblizer at low filler level (upto 30%). At higher filler loading (>30%), composites with compatiblizer had lower damping coefficient suggesting improved interfacial adhesion between wood and polypropylene. The damping in composite is attributed to the damping because of the composite constituents and damping at the interface. The damping because of interface was estimated using a model and was found to increase with the increase in filler loading. At higher filler content, damping due to interface in composites with compatiblizer was significantly lower than in composites without compatiblizer suggesting a better interfacial adhesion between the wood filler and polypropylene matrix with compatiblizer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Infrared light‐active shape memory polymer filled with nanocarbon particles
Authors: Leng Jinsong , Wu Xuelian , Liu Yanju
Published: July 2009

In addition to the fabrication of thermoset styrene‐based shape memory polymer (SMP) and its nanocomposite filled with nanocarbon particles, this study presents the effect of nanocarbon particles on infrared light‐active shape recovery behaviors of this type of SMP material. The experimental results reveal that both pure SMP and SMP filled with nanocarbon particles can be actuated by infrared light in vacuum, while shape memory effect shown by the composite is stronger than that of in pure SMP. Shape memory effect is evaluated by shape recovery ability and shape recovery speed in detail. Moreover, factors which would influence the infrared light‐active shape memory effect in SMP with/without nanocarbon particles are explored by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and infrared absorption characteristic tests. The better shape memory effect of the nanocomposite attributes to its higher storage modulus and higher infrared absorption capability. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Controlled/living RAFT polymerization of N‐phenyl maleimide and synthesis of its block copolymers
Authors: Li Anlong , Lu Jiang
Published: July 2009

The controlled/living radical polymerization of N‐phenyl maleimide (NPMI) was achieved using 2,2′‐azobisisobutyronitrile as the initiator and 2‐cyanopropyl‐2‐yl dithiobenzoate as the reversible addition‐fragmentation chain transfer agent at 75°C in dichloroethane/ethylene carbonate (60/40, w/w) mixed solvent. The block copolymers of polystyrene‐b‐polyNPMI and poly(n‐butyl methacrylate)‐b‐polyNPMI were successfully prepared by chain extension from dithiobenzoate‐terminated polystyrene and poly (n‐butyl methacrylate) to NPMI, respectively. The obtained NPMI‐based (co)polymers were characterized by gel permeation chromatography and 1H‐NMR spectroscopy. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Effect of high pressure carbon dioxide on the solubility and diffusivity of dichloromethane in polyetherimide
Authors: Law Yuk Yu , Balashova Ida M. , Danner Ronald P.
Published: July 2009

The high pressure inverse gas chromatography technique was used to study the effect of carbon dioxide on the solubility and diffusivity of dichloromethane in polyetherimide. CO2 was used as the carrier gas with pressures from 0.7 to 3.5 MPa and temperatures between 100 and 175°C. Similar data were obtained for the dichloromethane‐polyetherimide system using helium as the inert carrier gas. As a result of less favorable thermodynamic interactions between the polymer and solvent, the solubility of the dichloromethane was found to be decreased appreciably in the presence of CO2. The increased free volume in the polymer provided by the dissolved CO2 significantly increased the diffusion coefficient. When the temperature was increased the solubility was decreased while the diffusivity was increased. These behaviors have the potential to considerably improve devolatilization processes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation of thermoset composites from natural fibres and acrylate modified soybean oil resins
Authors: Åkesson Dan , Skrifvars Mikael , Walkenström Pernilla
Published: July 2009

Structural composites with a high content of renewable material were produced from natural fibres and an acrylated epoxidized soybean oil resin. Composites were prepared by spray impregnation followed by compression moulding at elevated temperature. The resulting composites had good mechanical properties in terms of tensile strength and flexural strength. Tensile testing as well as dynamical mechanical thermal analysis showed that increasing the fibre content, increased the mechanical properties. The resin can be reinforced with up to 70 wt % fibre without sacrifice in processability. The tensile modulus ranged between 5.8 and 9.7 GPa depending on the type of fibre mat. The study of the adhesion by low vacuum scanning electron microscopy shows that the fibres are well impregnated in the matrix. The aging properties were finally evaluated. This study shows that composites with a very high content of renewable constituents can be produced from soy bean oil resins and natural fibres. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
The synthesis of poly(butylene terephthalate) from terephthalic acid, part II: Assessment of the first stage of the polymerization process
Authors: Devroede Jan , Duchateau Robbert , Koning Cor E.
Published: July 2009

The production of poly(butylene terephthalate) (PBT) struggles with the formation of substantial amounts of tetrahydrofuran (THF). When PBT is synthesized from terephthalic acid (TPA) instead of dimethyl terephthalate (DMT), even more THF is formed, mainly during the first stage of the melt polymerization process. Although a lot of literature reports on the existence of this side reaction in both processes, to the best of our knowledge, a comparison, which reveals the importance of the acidity and insolubility of TPA on the THF formation, was never described. Finally, an interesting study was performed on the THF formation during the synthesis of PBT from mixtures of DMT and TPA as well as from the completely soluble monomethyl terephthalate (MMT). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Kinetic and mechanistic modeling of acid‐catalyzed degradation of polymers with various cracking catalysts
Authors: Lin Yeuh‐Hui , Yang Mu‐Hoe
Published: July 2009

A new approach is presented that combines kinetic and mechanistic considerations which take into account chemical reactions and catalyst deactivation in the modeling of the catalytic degradation of polymers. Though acid‐catalyzed hydrocarbon cracking reactions involve a large number of compounds, reactions and catalyst deactivation and are very complex, the model gives a good representation of experimental results from the degradation of polyethylene and polypropylene over fluidized acidic catalysts. This model provides the benefits of product selectivity for the chemical composition such as alkanes, alkenes, aromatics, and coke in relation to the effect of structurally different polymer feeds, the performance of the catalyst and the selection of their particle sizes, and the influence of different reaction temperatures. It is an improvement of the currently available empirical “lumping” techniques which usually are severely restricted in terms of product definitions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Melt spinning and metal chloride vapor curing process on polymethylsilsesquioxane as SiOC fiber precursor
Authors: Narisawa Masaki , Sumimoto Ryu‐Ichi , Kita Ken‐Ichiro , Kado Hiroyuki , Mabuchi Hiroshi , Kim Young‐Wook
Published: July 2009

Melt spinning process of polymethylsilsesquioxane (PMSQ) at 403–453 K was investigated as a SiOC fiber precursor in terms of averages and distributions of spun fiber diameters. Because of fusible character of PMSQ at low temperature, the spun fibers were exposed to vapors of various metal chlorides (SiCl4, Si(CH3)Cl3, TiCl4, and BCl3) to promote the fiber curing. Cured fibers were investigated by FTIR and TG analyses. In a case of the fiber synthesized with SiCl4 curing, tensile tests on the pyrolyzed fibers were performed. Exposure of the synthesized fiber at high temperature with a flame of an oxygen‐gas burner was examined. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Atom transfer radical homo‐ and copolymerization of styrene and methyl acrylate initiated with trichloromethyl‐ terminated poly(vinyl acetate) macroinitiator: A kinetic study
Authors: Semsarzadeh Mohammad Ali , Abdollahi Mahdi
Published: July 2009

Atom transfer radical bulk copolymerization of styrene (St) and methyl acrylate (MA) initiated with trichloromethyl‐terminated poly(vinyl acetate) macroinitiator was performed in the presence of CuCl/PMDETA as a catalyst system at 90°C. Linear dependence of ln[M]0/[M] versus time data along with narrow polydispersity of molecular weight distribution revealed that all the homo‐ and copolymerization reactions proceed according to the controlled/living characteristic. To obtain more reliable monomer reactivity ratios, the cumulative average copolymer composition at moderate to high conversion was determined by 1H‐NMR spectroscopy. Reactivity ratios of St and MA were calculated by the extended Kelen‐Tudos (KT) and Mao‐Huglin (MH) methods to be rSt = 1.018 ± 0.060, rMA = 0.177 ± 0.025 and rSt = 1.016 ± 0.053, rMA = 0.179 ± 0.023, respectively, which are in a good agreement with those reported for the conventional free‐radical copolymerization of St and MA. Good agreement between the theoretical and experimental composition drifts in the comonomer mixture and copolymer as a function of the overall monomer conversion were observed, indicating that the reactivity ratios calculated by copolymer composition at the moderate to high conversion are accurate. Instantaneous copolymer composition curve and number‐average sequence length of comonomers in the copolymer indicated that the copolymerization system tends to produce a random copolymer. However, MA‐centered triad distribution results indicate that the spontaneous gradient copolymers can also be obtained when the mole fraction of MA in the initial comonomer mixture is high enough. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Dynamic mechanical properties of cotton/polypropylene commingled composite systems
Authors: Elappunkal Tomlal Jose , Mathew Rani , Thomas P.C. , Thomas Sabu , Joseph Kuruvilla
Published: July 2009

The dynamic mechanical properties of cotton/polypropylene (PP) commingled composite system was studied with reference to the fiber content, chemical treatments with potassium permanganate and maleic anhydride modified PP, processing conditions and applied frequency. Side by side commingling of matrix and reinforcing fibers was adopted for the fabrication of composite laminates as they provide the shortest melt flow distance during the melting of matrix fibers. This method can also be used for the recycling of textile wastes. The storage modulus was found to increase with the fiber content across a range of temperatures. The loss factor was found to decrease with the increase in fiber content while the glass transition temperature increases. The chemical treatments increase the value of storage modulus. A master curve was constructed and also made a comparison between the experimental results and the theoretically predicted values. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Metal–π Interactions Dominate in the Solid‐State Structures of Molecular Heterobimetallic Alkali‐Metal–Europium(II) Aryloxo Complexes
Authors: Deacon Glen B. , Junk Peter C. , Moxey Graeme J.
Published: July 2009

Treatment of Eu metal, 2,6‐diphenylphenol (HOdpp), and MOdpp (M=Na, K) at elevated temperature in the presence of mercury afforded heterobimetallic complexes which were structurally characterized after crystallization from toluene. The structures of [MEu(Odpp)3]⋅nPhMe (M=Na, n=1, 1; K, n=2.5, 2) consist solely of bridging aryloxide ligands and feature extensive π‐Ph–metal interactions. Rather than a heterobimetallic species, treatment of Eu metal and HOdpp with LiOdpp under similar conditions afforded a number of products, including a mixed‐valent europium complex, [Eu2(Odpp)3][Eu(Odpp)4]⋅4 PhMe (3). The structural framework of the [Eu2(Odpp)3]+ cation of 3 is similar to that of the molecular heterobimetallics 1 and 2, including the presence of π‐Ph–Eu interactions. The reluctance of the reaction to provide a Eu/Li heterobimetallic complex was exemplified by the simultaneous crystallization of [Eu2(Odpp)4]⋅PhMe (6) and the homoleptic cubane [Li4(Odpp)4]⋅2 C6H14 (5) from toluene/hexane.
Bioencapsulation of apomyoglobin in nanoporous organosilica sol–gel glasses: Influence of the siloxane network on the conformation and stability of a model protein
Authors: Menaa Bouzid , Miyagawa Yuya , Takahashi Masahide , Herrero Mar , Rives Vicente , Menaa Farid , Eggers Daryl K.
Published: July 2009

Nanoporous sol–gel glasses were used as host materials for the encapsulation of apomyoglobin, a model protein employed to probe in a rational manner the important factors that influence the protein conformation and stability in silica‐based materials. The transparent glasses were prepared from tetramethoxysilane (TMOS) and modified with a series of mono‐, di‐ and tri‐substituted alkoxysilanes, RnSi(OCH3)4−n (R = methyl‐, n = 1; 2; 3) of different molar content (5, 10, 15%) to obtain the decrease of the siloxane linkage (SiOSi). The conformation and thermal stability of apomyoglobin characterized by circular dichroism spectroscopy (CD) was related to the structure of the silica host matrix characterized by 29Si MAS NMR and N2 adsorption. We observed that the protein transits from an unfolded state in unmodified glass (TMOS) to a native‐like helical state in the organically modified glasses, but also that the secondary structure of the protein was enhanced by the decrease of the siloxane network with the methyl modification (n = 0 < n = 1 < n = 2 < n = 3; 0 < 5 < 10 < 15 mol %). In 15% trimethyl‐modified glass, the protein even reached a maximum molar helicity (−24,000 deg. cm2 mol−1) comparable to the stable folded heme‐bound holoprotein in solution. The protein conformation and stability induced by the change of its microlocal environment (surface hydration, crowding effects, microstructure of the host matrix) were discussed owing to this trend dependency. These results can have an important impact for the design of new efficient biomaterials (sensors or implanted devices) in which properly folded protein is necessary. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 895–906, 2009.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Bridging the theory‐and‐practice gap: Mediator power in practice
Authors: Gerami Arghavan
Published: July 2009

Although mediators are assumed to be neutral third parties, effective fulfillment of their role involves exercising a significant amount of authority and power. Mediators employ a range of approaches, orientations, and strategies. This article reviews some of the scholarship in this area. It then examines the various dimensions of mediator power, looking specifically at (1) the nature of mediator power and (2) its exercise of power through knowledge and expertise, through designing and controlling the process through reframing, and through imposing pressure to settle. Finally, the article discusses “ethical mediation” in light of mediator power.
Practice note: Community mediation as social intervention
Authors: Neves Tiago
Published: July 2009

Rather than understanding mediation solely as an attempt at problem solving between two individuals, this article examines the possibility of mediation as a social intervention designed to bring systemic change. If the mediation process is to have broader societal impact, one must address the questions this raises related to the mediator's role and neutrality. This article uses the case study of mediation in Brazil as a basis to launch the discussion.
Partial discharge pattern recognition based on optimal uncorrelated discriminant vectors in GIS
Authors: Zhang Xiaoxing , Yao Yao , Tang Ju
Published: July 2009

While partial discharge (PD) pattern recognition is widely considered as an important method to evaluate insulation state, the major problem encountered in recognition is to extract PD pattern features. This paper designed four typical physical models of defects in GIS, and PD three‐dimensional patterns were constructed based on mass sample gathered by the very high frequency (VHF) and high‐speeds systems. A principal component analysis (PCA)–statistically uncorrelated optimal discriminant vectors (SUODV) method is put forward based on 3D patterns images. Firstly, the PCA is employed to condense the dimension of PD images, then uncorrelated discriminate features are extracted by improved SUODV algorithm, and the minimum distance classifier was constructed as classifier. The recognition results showed that this method can effectively classify four kinds of defects in GIS. Copyright © 2008 John Wiley & Sons, Ltd.
Tuning‐in to the beat: Aesthetic appreciation of musical rhythms correlates with a premotor activity boost
Authors: Kornysheva Katja , von Cramon D.Yves , Jacobsen Thomas , Schubotz Ricarda I.
Published: July 2009

Listening to music can induce us to tune in to its beat. Previous neuroimaging studies have shown that the motor system becomes involved in perceptual rhythm and timing tasks in general, as well as during preference‐related responses to music. However, the role of preferred rhythm and, in particular, of preferred beat frequency (tempo) in driving activity in the motor system remains unknown. The goals of the present functional magnetic resonance imaging (fMRI) study were to determine whether the musical rhythms that are subjectively judged as beautiful boost activity in motor‐related areas and if so, whether this effect is driven by preferred tempo, the underlying pulse people tune in to. On the basis of the subjects' judgments, individual preferences were determined for the different systematically varied constituents of the musical rhythms. Results demonstrate the involvement of premotor and cerebellar areas during preferred compared to not preferred musical rhythms and indicate that activity in the ventral premotor cortex (PMv) is enhanced by preferred tempo. Our findings support the assumption that the premotor activity increase during preferred tempo is the result of enhanced sensorimotor simulation of the beat frequency. This may serve as a mechanism that facilitates the tuning‐in to the beat of appealing music. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.
Focusing effects ofL‐dopa in Parkinson's disease
Authors: Ng Bernard , Palmer Samantha , Abugharbieh Rafeef , McKeown Martin J.
Published: July 2009

Previous fMRI motor studies in Parkinson's disease (PD) have suggested thatL‐dopa may “normalize” areas of hypo‐ and hyperactivity. However, results from these studies, which were largely based on analyzing BOLD signal amplitude, have been conflicting. Examining only amplitude changes at distinct loci may thus be inadequate in fully capturing the activation changes induced byL‐dopa. In this article, we extended prior analyses on the effects ofL‐dopa by investigating both amplitude and spatial changes of brain activation before and afterL‐dopa. Ten subjects with PD, both on and off medication, and ten healthy, age‐matched controls performed a visuo‐motor tracking task in which they sinusoidally squeezed a bulb at 0.25, 0.5, and 0.75 Hz. This task was contrasted with static squeezing to generate fMRI activation maps. To investigate the effects ofL‐dopa, we examined the amplitude and spatial variance of the BOLD response within anatomically‐defined regions of interest (ROIs).L‐dopa had significant main effects on the amplitude of BOLD signal in bilateral primary motor cortex and left SMA. In contrast,L‐dopa‐mediated spatial changes were apparent in bilateral cerebellar hemispheres, M1, SMA, and right prefrontal cortex. Moreover,L‐dopa appeared to normalize the spatial distribution of ROI activation in PD to that of the controls. Specifically,L‐dopa had a “focusing” effect on activity—an effect more pronounced than the typically‐measured fMRI amplitude changes. This observation is consistent with modeling studies, which demonstrated that dopamine increases the signal‐to‐noise ratio at the neuronal level with a resultant focusing of representations at the macroscopic level. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.
Nuclear factor erythroid 2–related factor 2 is a positive regulator of human bile salt export pump expression # †
Authors: Weerachayaphorn Jittima , Cai Shi-Ying , Soroka Carol J. , Boyer James L.
Published: July 2009

The bile salt export pump (BSEP) is the major determinant of bile salt–dependent bile secretion, and its deficiency leads to cholestatic liver injury. BSEP/Bsep gene expression is regulated by the nuclear farnesoid X receptor. However, BSEP expression, though reduced, is retained in the livers of Fxr
−/− mice, indicating that additional transcriptional factors may regulate its expression. Nuclear factor erythroid 2–related factor 2 (Nrf2) plays a major role in response to oxidative stress by binding to antioxidant-responsive elements that regulate many hepatic phase I and II enzymes as well as hepatic efflux transporters. Computer software analysis of human BSEP reveals two musculo-aponeurotic fibrosacroma (Maf) recognition elements (MAREs) from the sequence in the proximal promoter region where Nrf2 may bind. In this study, we assessed whether Nrf2 plays a role in human BSEP expression and if this might be mediated by MAREs. Oltipraz, a potent activator of Nrf2, increased BSEP messenger RNA expression by approximately seven-fold in HepG2 cells and protein by approximately 70% in human hepatocytes. Small interfering RNAs lowered NRF2 expression in HepG2 cells and prevented the up-regulation of BSEP by oltipraz. Human BSEP promoter activity was stimulated by Nrf2 in a dose-dependent manner in luciferase reporter assays. Mutations of the predicted MARE1, but not MARE2, abolished this Nrf2 transcriptional activation. Chromatin immunoprecipitation assays also demonstrated that Nrf2 specifically bound to MARE1, but not MARE2 regions in the BSEP promoter in HepG2 cells. Electrophoretic mobility shift assays further demonstrated direct binding of MARE1 in the BSEP promoter. Conclusion: Nrf2 is a positive transcriptional regulator of human BSEP expression. Pharmacological activation of Nrf2 may be beneficial for cholestatic liver injury. (Hepatology 2009.)