bluuebunny/crossref_metadata_2025 huggingface dataset:
Imaging the effect of dielectric breakdown in a multilayered polymer film
Authors: Wolak Mason A. , Wan Alan S. , Shirk James S. , Mackey Matt , Hiltner Anne , Baer Eric
Published: September 2011

The dielectric strength and energy storage capability of poly(vinylidene fluoride‐hexafluoropropylene) copolymer (P[VDF‐HFP]) films are enhanced by interleaving layers of PVDF copolymer with thin layers of polycarbonate (PC). To gain insight into the breakdown processes in such materials, focused ion beam (FIB) milling in conjunction with scanning electron microscopy (SEM) was used to study the effect of a breakdown on the film. FIB can sequentially mill cross sections that are each imaged by SEM. The technique can provide quasi‐3D images across the film and give a detailed view of the damage caused by an electrical breakdown. Here, breakdowns initiated using a needle‐plane electrode configuration were imaged. In homogeneous films, the damage was confined to the small volume at the pinhole site. In 32‐layer 50/50 PC/P[VDF‐HFP] multilayer films, damage extending laterally up to ∼ 15 μm into the film along the layer interfaces was seen. In addition to the delamination, layer buckling and distortion were apparent. The damage varied with the sample orientation, but the images indicate that the interfaces play an important role in the breakdown. They suggest that modifying the interface properties can be a strategy to further improve the dielectric strength of multilayer polymer dielectric materials. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis and rheological properties of nickel‐zinc ferrite polymer nanocomposites
Authors: Moeen S. Jebelli , Vaezi M. R. , Yousefi A. A. , Ghasemi E.
Published: September 2011

In this work, the ferrimagnetic nickel‐zinc ferrite nanopowder was synthesized via citrate‐ethylene glycol processing, followed by the preparation of the epoxy‐based nanocomposite. The materials were characterized using X‐ray diffraction (XRD), simultaneous thermal analysis (STA), alternative gradient force magnetometer (AGFM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the sample calcined at 1000°C for 1 h had the best crystallinity, and the calculated crystallite size of this sample was ∼ 105 nm. The rheological properties and the magnetoviscous effect of the nanocomposites were studied by a standard rotating rheometer. The effects of the magnetic fields and shear rate with respect to time were investigated, and the results were discussed in terms of aggregates and magnetic field‐induced structures. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Functionalization of lignin: Synthesis of lignophenol‐graft‐poly(2‐ethyl‐2‐oxazoline) and its application to polymer blends with commodity polymers
Authors: Nemoto Tadamasa , Konishi Gen‐ichi , Tojo Yusuke , An Youn Chul , Funaoka Masamitsu
Published: September 2011

Lignophenol (LP)‐graft‐poly(2‐ethyl‐2‐oxazoline) (POZO) was prepared to reuse lignin, an industrial waste material, and to produce novel LP‐based polymer blends with poly(vinyl chloride) (PVC), poly(bisphenol A carbonate) (PC), polyvinylpyrrolidone (PVP), and polystyrene (PSt) as commodity polymers. The resulting graft polymer was soluble in various types of organic solvents such as chloroform, THF, acetone, and methanol, unlike LP. The miscibility of LP‐graft‐POZO with commodity polymers was measured by differential scanning calorimetry (DSC) to determine the glass transition temperatures (Tg). In the cases of the blends of LP‐graft‐POZO with PVC, PC, and PVP, the Tg values decreased during the second scan. Moreover, in the cases of the blends with PVC and PVP, the Tg values were not detected during the third scan. Therefore, it was inferred that LP‐graft‐POZO was miscible with PVC, PC, and PVP while forming single phases; in particular, the blends of LP‐graft‐POZO with PVC and PVP exhibited a secondary miscibility because the Tg values were not detected. Furthermore, the blend of LP‐graft‐POZO with PC exhibited better thermostability than LP and LP‐graft‐POZO. These results indicated that LP blended with POZO could be used as a polymer additive and as an adhesive to combine different polymers, organic–inorganic polymers, etc. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effect of KOH concentration in the gel polymer electrolyte for direct borohydride fuel cell
Authors: Ng Pao Ling , Jamaludin Aliyah , Alias Yatimah , Basirun Wan Jefrey , Ahmad Zainal Arifin , Mohamad Ahmad Azmin
Published: September 2011

The performance of a direct borohydride fuel cell (DBFC) based on a polyacrylamide (PAAm) gel polymer electrolyte system is investigated at different electrolyte concentrations. The DBFC, constructed using 2M sodium borohydride (NaBH4) as the fuel and potassium hydroxide (KOH) solution gelled with PAAm as the electrolytes yield the highest electrical conductivity of 2.73 × 10−1 S cm−1 at 6M KOH. The optimized composition, PAAm + 2M NaBH4 + 6M KOH, and the selected composition, PAAm + 2M NaBH4 + 3M KOH are then used in preparing the cells. Open‐circuit voltages for fuel cells is about 0.85–0.92 V, and the discharge characteristic produce discharge capacities of about 257.12–273.12 mAh cm−2 for cells with PAAm‐6M KOH. Current‐voltage and current density‐power density plots and internal resistance for both cells are almost the same. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Electrical and optical properties of polymer‐Au nanocomposite films synthesized by magnetron cosputtering
Authors: Liu Fanjung , Shang Songmin , Duan Yajun , Li Liang
Published: September 2011

Polymer‐Au nanocomposite films were prepared by co‐sputtering from two independent magnetron sources. By sputtering from gold and polytetrafluoroethylene (PTFE) magnetrons, we prepared homogenous composite films using a rotatable sample holder. The microstructure of the nanocomposites was studied by transmission electron microscopy (TEM). The resistivity drops from 107 to 10−3 Ohm cm over a narrow range of metal content. The thin composite films show a strong optical absorption in the visible region due to surface plasmon resonances. The optical absorption has a strong dependence on the metal content, showing a red shift of the absorption peak from 550 nm to more than 700 nm with increasing gold content. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Study on mixed‐mode fracture characterization in functionally graded materials
Authors: Liu D. L. , Yao X. F. , Ma Y. J. , Xu W.
Published: September 2011

The fracture characterizations on mixed‐mode crack of functionally graded materials (FGMs) are investigated using digital speckle correlation method (DSCM). The stress intensity factors at mixed‐mode crack tip are obtained from digital speckle displacements fields. In combination with finite elements simulation results, the influences of gradient coefficients on fracture behavior of mixed‐mode cracks are analyzed. All the results show that the influence of gradient coefficients on fracture modes is not noticeable, and the stress intensity factor at the crack tip in graded materials are clearly influenced by the gradient coefficients, i.e., the stress intensity factors decrease with the increasing of gradient coefficients. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Flame‐retardant polycarbonate/acrylonitrile‐butadiene‐styrene based on red phosphorus encapsulated by polysiloxane: Flame retardance, thermal stability, and water resistance
Authors: Jian Rong‐Kun , Chen Li , Hu Zhi , Wang Yu‐Zhong
Published: September 2011

Red phosphorus encapsulated by polysiloxane (MRP) was prepared, and the chemical structure and morphology of MRP were characterized by FTIR and TEM, respectively. A series of flame retardant polycarbonate/acrylonitrile‐butadiene‐styrene containing MRP (PC/ABS/MRP) were prepared via melt‐blending. The flame retardance of PC/ABS/MRP was investigated by limiting oxygen index (LOI) and UL‐94 test. It was shown that the LOI value was increased to 27.7 and UL‐94 achieved a V‐0 rating at a 15 wt % loading of MRP. Cone calorimetric results showed that the peak of heat release rate (PHRR) of PC/ABS/15% MRP decreased from 452.7 to 198.0 kW/m2, and the total heat release decreased from 92.9 to 60.7 MJ/m2 compared with virgin PC/ABS. Thermal stability analysis showed that the char yield of the PC/ABS/15% MRP increased from 0 to 16.1 wt % under air atmosphere, and from 15.2 to 27.4 wt % under nitrogen atmosphere compared to virgin PC/ABS, respectively. The sample PC/ABS/15% MRP also showed excellent water resistance of flame retardance in 70°C water for 168 h. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effect of membrane pore size on the pH‐sensitivity of polyethersulfone hollow fiber ultrafiltration membrane
Authors: Li Lulu , Xiang Tao , Su Baihai , Li Huijuan , Qian Bosi , Zhao Changsheng
Published: September 2011

In our recent study, pH‐sensitive polyethersulfone (PES) hollow fiber membranes were prepared by blending poly (acrylonitrile‐co‐acrylic acid) (PANAA), and the electroviscous effect had great effect on the water flux change. While the question remains: is the water flux change caused by the electroviscous effect for all the membranes with different pore sizes? Herein, pH‐sensitive hollow fiber membranes with different pore sizes were prepared. The pore size and the theoretic water flux were calculated through the ultrafiltration of polyethylene glycol (PEG) solution. Comparing the calculated fluxes and the experimental ones, we found that the water flux change was mainly caused by the pore size change at the pH value larger than pKa, while that was caused by both the pore size change and the electroviscous effect when pH value was smaller than the pKa, and the pore size change was caused by the ionization of the COOH in the copolymer. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Photo‐cross‐linked biodegradable thermo‐ and pH‐responsive hydrogels for controlled drug release
Authors: Zhao Changwen , He Pan , Xiao Chunsheng , Gao Xiaoye , Zhuang Xiuli , Chen Xuesi
Published: September 2011

A new strategy was developed to prepare thermo‐ and pH‐sensitive hydrogels by the crosslinking of poly(N‐isopropylacrylamide) with a biodegradable crosslinker derived from poly(L‐glutamic acid). Hydrogels were fabricated by exposing aqueous solutions of precursor containing photoinitiator to UV light irradiation. The swelling behaviors of hydrogels at different temperatures, pHs, and ionic strengths were examined. The hydrogels shrank under acidic condition or at temperature above their collapse temperature and would swell in neutral or basic media or at lower temperature. These processes were reversible as the pH or temperature changed. All hydrogels exhibited no weight loss in the simulated gastric fluid but degraded rapidly in the simulated intestinal condition. Bovine serum albumin were used as a model protein drug and loaded into the hydrogels. The in vitro drug release experiment was carried out at different pH values and temperatures. The pH and temperature dependent release behaviors indicated the promising application of these materials as stimuli‐responsive drug delivery vehicles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Direct formation of “artificial wool” nanofiber via two‐spinneret electrospinning
Authors: Li Congju , Wang Jiaona , Zhang Binfei
Published: September 2011

To reproduce the excellent characteristics of natural fibers like wool and proteins, a novel two‐spinneret electrospinning technology was demonstrated in this communication, which can generate three‐dimensional self‐crimp fibers of HSPET/PTT, HSPET/PAN and PU/PAN directly. In the apparatus, two spinnerets were used to prevent gel formation or precipitation of the polymer, and the voltages of opposite polarities were applied to the spinnerets respectively. And the elecctrospun fibers morphology was observed by using scanning electron microscopy (SEM). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effect of iron carboxylates on the photodegradability of polypropylene. II. Artificial weathering studies
Authors: Rajakumar K. , Sarasvathy V. , Chelvan A. Thamarai , Chitra R. , Vijayakumar C. T.
Published: September 2011

The various iron carboxylates such as ferric caprate, ferric laurate, ferric myristate, ferric palmitate, and ferric stearate were synthesized to enhance the photodegradability of polypropylene (PP). The prodegradants (0.2%) synthesized were blended with virgin PP and then blown into films. All the PP films mentioned were exposed to ultraviolet (UV) radiation of 365 nm at room temperature to study the photodegradation behavior of PP with and without the prodegradants under artificial weathering conditions. The photoirradiated films were found to degrade after certain hours of UV exposure, which could be found from the steep increase of hydroxyl, carbonyl, lactone, ester, carboxylic acid, and crystallinity index. At the same time, a sudden decrease of elongation at break percentages and tensile strength; development of surface cracks indicated the scission of the main chain of the PP. The results revealed that PP containing prodegradants degraded at a faster rate than the virgin material. However, the effectiveness of the prodegradants for the photodegradation of PP was found to be in the order: ferric caprate > ferric laurate > ferric myristate > ferric palmitate > ferric stearate. The results showed that the number of carbon atoms present in the alkyl part of the various prodegradants played a vital role in the degradation phenomenon. Furthermore, it could be concluded that the mobility of the alkyl radicals formed from the decomposition of the incorporated prodegradants during artificial weathering played a prominent role in the photooxidative degradation behavior of PP films. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Influence of the base and diluent methacrylate monomers on the polymerization stress and its determinants
Authors: Fróes‐Salgado N. R. G. , Boaro L. C. , Pick B. , Pfeifer C. S. , Francci C. E. , Méier M. M. , Braga R. R.
Published: September 2011

The aim of this study was to evaluate the effect of the association between bisphenol‐A diglycidyl dimethacrylate (BisGMA) or its ethoxylated version (BisEMA) with diluents derived from the ethylene glycol dimethacrylate (EGDMA), with increasing number of ethylene glycol units (1: EGDMA, 2: DEGDMA, 3: TEGDMA, or 4: TETGDMA), or trimethylol propane trimethacrylate (TMPTMA) or 1,10‐decanediol dimethacrylate (D3MA) on polymerization stress, volumetric shrinkage, degree of conversion, maximum rate of polymerization (Rpmax), and elastic modulus of experimental composites. BisGMA containing formulations presented lower shrinkage and stress but higher modulus and Rpmax than those containing BisEMA. TMPTMA presented the lowest stress among all diluents, as a result of lower conversion. EGDMA, DEGDMA, TEGDMA, and TETGDMA presented similar polymerization stress which was higher than the stress presented by D3MA and TMPTMA. D3MA presented similar conversion when copolymerized with both base monomers. The other diluents presented higher conversion when associated with BisEMA. EGDMA showed similar shrinkage compared with DEGDMA and higher than the other diluents. The lower conversion achieved by TMPTMA did not jeopardize its elastic modulus, similar to the other diluents. Despite the similar conversion presented by D3MA in comparison with EGDMA and DEGDMA, its lower elastic modulus may limit its use. Rather than proposing new materials, this study provides a systematic evaluation of off the shelf monomers and their effects on stress development, as highlighted by the analysis of conversion, shrinkage and modulus, to aid the optimization of commercially available materials. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Studies of fluorine‐containing bismaleimide resins part I: Synthesis and characteristics of model compounds
Authors: Wang Zen‐You , Ho Jiau‐Ching , Shu Wei‐Jye
Published: September 2011

A series of fluorine‐containing bismaleimide (FBMI) monomers are synthesized by a 3‐step reaction for using as the applications of low‐k materials. The synthesized FBMI monomers are characterized by the 1H, 13C, 19F nuclear magnetic resonance (NMR) spectroscopy and element analysis. These FBMI monomers react with free radical initiator or self‐cure to prepare FBMI‐polymers. All the self‐curing FBMI resins have the glass transition temperatures (Tg) in the range of 128–141°C and show the 5% weight loss temperatures (T5%) of 235–293°C in nitrogen atmosphere. The higher heat resistance of self‐curing FBMI resin relative to FBMI‐homopolymer is due to its higher crosslinking density. The FBMI resins exhibit improved dielectric properties as compared with commercial bismaleimide (BMI) resins with the dielectric constants (Dk) lower than 2.49, which is related to the low polarizability of the CF bond and the large free volume of CF3 groups in the polymers. Besides, the flame retardancy of all these FBMI resins could be enhanced via the introduction of Br‐atom. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Rheological properties of concentrated solutions of agarose in ionic liquid
Authors: Horinaka Jun‐ichi , Yasuda Ryosuke , Takigawa Toshikazu
Published: September 2011

The rheological properties of agarose solutions were examined under the effect of entanglement coupling between agarose chains. Agarose solutions were prepared by using an ionic liquid 1‐butyl‐3‐methylimidazolium chloride as a solvent. The concentration of agarose was varied from 1.1 × 101–2.1 × 102 kg m−3. The master curves of the angular frequency (ω) dependence of the storage modulus (G′) and the loss modulus (G″) showed a rubbery region in the middle ω region and a flow region at low ω region, respectively. The molecular weight between entanglements (Me) for agarose was calculated from the plateau modulus. Moreover, Me for agarose melt was determined to be 2.3 × 103 from the concentration dependence curve of Me. By using well‐known empirical relations in polymer rheology, information on molecular characteristics of sample agarose was derived. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Increased levels of the cell cycle inhibitor protein, dacapo, accompany 20‐hydroxyecdysone‐induced G1 arrest in a mosquito cell line
Authors: Gerenday Anna , Fallon Ann M.
Published: September 2011

When treated with the steroid hormone 20‐hydroxyecdysone (20E), C7‐10 cells from the mosquito, Aedes albopictus, arrest in the G1 phase of the cell cycle. To explore whether 20E‐mediated cell cycle arrest proceeds through increased levels of cell cycle inhibitor (CKI) proteins, we cloned the Ae. albopictus homolog of dacapo, the single member of the Cip/Kip family of CKI proteins known from Drosophila melanogaster. The Ae. albopictus dacapo cDNA encoded a 261‐amino acid homolog of the Aedes aegypti protein XP_001651102.1, which is encoded by an ∼23 kb gene containing three exons. Like dacapo from D. melanogaster, the ∼27 kDa protein from Aedes and Culex mosquitoes contained several S/TXXE/D motifs corresponding to potential protein kinase CK2 phosphorylation sites, and a binding site for proliferating cell nuclear antigen (PCNA). When extracts from cells treated with 20E were analyzed by western blotting, using a primary antibody to synthetic peptides from the mosquito dacapo protein, up‐regulation of an ∼27 kDa protein was observed within 24 h, and the abundance of the protein further increased by 48 h after hormone treatment. This is the first investigation of a cell cycle inhibitory protein in mosquitoes. The results reinforce growing evidence that 20E affects expression of proteins that regulate cell cycle progression. © 2011 Wiley Periodicals, Inc.
Synthesis and Free Radical Scavenging Activity of Coumarin Derivatives Containing a 2‐Methylbenzothiazoline Motif
Authors: Khoobi Mehdi , Emami Saeed , Dehghan Gholamreza , Foroumadi Alireza , Ramazani Ali , Shafiee Abbas
Published: September 2011

Coumarin and benzothiazole scaffolds can be found in a number of natural or synthetic antioxidants. In an effort to develop a novel radical scavenger and potential antioxidant, a series of coumarin derivatives containing 2‐methylbenzothiazoline motif and related compounds was synthesized and evaluated for their DPPH (1,1‐diphenyl‐2‐picrylhydrazyl) and ABTS•+ (2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonic acid) radicals scavenging activities. Among them, 7‐hydroxy‐3‐(2‐methyl‐2,3‐dihydrobenzo[d]thiazol‐2‐yl)‐2H‐chromen‐2‐one (3e) has shown a significant free radical scavenging activity. From the structure–activity point of view, it was found that phenolic coumarin ring and benzothiazoline moiety in target compounds may contribute to the scavenging activity against free radicals.
Design, Synthesis and Antifungal Activity of Some New Imidazole and Triazole Derivatives
Authors: Rezaei Zahra , Khabnadideh Soghra , Zomorodian Kamiar , Pakshir Kyvan , Kashi Giti , Sanagoei Narges , Gholami Sanaz
Published: September 2011

Triazole and imidazole are incorporated into the structures of many antifungal compounds. In this study a novel series of 1,2,4‐triazole, imidazole, benzoimidazole, and benzotriazole derivatives was designed as inhibitors of cytochrome P450 14α‐demethylase (14DM). These structures were docked into the active site of MT‐CYP51, using Autodock program. Sixteen compounds with the best binding energy were synthesized. The chemical structures of the new compounds were confirmed by elemental and spectral (1H‐NMR and Mass) analyses. All compounds were investigated for antifungal activity against Candida albicans, Candida tropicalis, Candida glabrata, Candida parapeilosis, Candida kruzei, Candida dubliniensis, Aspergillus fomigatus, Aspergillus flavus, Microsporum canis, Microsporum gypseum, Trichophyton mentagrophyte, Epidermophyton floccosum. Some compounds showed excellent in‐vitro antifungal activity against most of the tested fungi. Compounds 2, 9, and 10 had antifungal activity against several resistant fungi against fluconazole and itraconazole.
Synthesis, Characterisation and Biological Evaluation of Copper and Silver Complexes based on Acetylsalicylic Acid
Authors: Rubner Gerhard , Bensdorf Kerstin , Wellner Anja , Bergemann Silke , Gust Ronald
Published: September 2011

Metalcarbonyl complexes with ligands derived from acetylsalicylic acid demonstrated high cytotoxic potential against various tumor cell lines and strong inhibition of the cyclooxygenase enzymes COX‐1 and 2. In this study we tried to achieve comparable effects with [alkyne]silver or copper trifluoromethanesulfonate complexes which are more hydrophilic then the uncharged metalcarbonyl derivatives. All compounds were evaluated for growth inhibition against breast (MCF‐7, MDA‐MB 231) and colon cancer (HT‐29) cell lines and for COX‐1 and COX‐2 inhibitory effects at isolated isoenzymes. Pure ligands showed neither cytotoxic nor COX‐inhibitory effects. While the silver complexes of (but‐2‐ynyl)‐2‐acetoxybenzoate (But‐ASS‐Ag) and (but‐2‐yne‐1,4‐diyl)‐bis(2‐acetoxybenzoate) (Di‐ASS‐But‐Ag) were strong cytostatics, only the copper complex Di‐ASS‐But‐Cu was active. At the COX enzymes the complexes were more effective than their ligands and aspirin.
Anti‐Tumor Activity of New Artemisinin–Chalcone Hybrids
Authors: Xie Lijun , Zhai Xin , Liu Chun , Li Peng , Li Yangxiong , Guo Guoxian , Gong Ping
Published: September 2011

In an attempt to develop potent and selective anti‐tumor agents, three new series of artemisinin–chalcone hybrids 10a–10g, 11a–11g and 12a–12h were designed, synthesized and screened for their anti‐tumor activity against five cell lines (HT‐29, A549, MDA‐MB‐231, HeLa and H460) in vitro. Among compounds 10a–g and 11a–11g, most of them displayed enhanced activity and good selectivity toward HT‐29 and HeLa cell lines with IC50 values ranging from 0.12 to 0.85 µM as compared with DHA (dihydroartemisinin). Compounds 10a and 11a are most active toward HeLa cells with IC50 values of 0.12 and 0.19 µM. The results revealed that the presence of chalcone moiety is beneficial to their activity and selectivity. In addition, compounds 12a‐12h containing a ‘reversed chalcone’ moiety showed only slight improvement in activity than those of DHA.
The response of T cells to interleukin‐6 is differentially regulated by the microenvironment of the rheumatoid synovial fluid and tissue
Authors: Hidalgo Ester , Essex Sarah J. , Yeo Lorraine , Curnow S. John , Filer Andrew , Cooper Mark S. , Thomas Andrew M. , McGettrick Helen M. , Salmon Michael , Buckley Christopher D. , Raza Karim , Scheel‐Toellner Dagmar
Published: September 2011

Objective

Interleukin‐6 (IL‐6) is a proinflammatory cytokine with regulatory effects on the survival and differentiation of T cells. It exerts its biologic function in 2 ways: by directly binding to the IL‐6 receptor (IL‐6R; CD126) or via trans‐signaling, in which soluble IL‐6R/IL‐6 complexes bind to the signaling component CD130. This study was undertaken to assess the expression and regulation of CD126 and CD130 and determine how these affect the response of CD4+ T cells to IL‐6 in the joints of patients with rheumatoid arthritis (RA).

Methods

Flow cytometry and immunofluorescence microscopy were used to determine the expression, function, and regulation of CD126 and CD130 in CD4+ T cells from the peripheral blood (PB), synovial fluid (SF), and synovial tissue of RA patients.

Results

Compared to the findings in RA PB, CD4+ T cells in the SF and synovial tissue expressed low levels of CD126. In contrast, whereas CD4+ T cell expression of CD130 was minimal in the SF, its level in the synovial tissue was high. Consistent with this phenotype, synovial tissue T cells responded to trans‐signaling by soluble IL‐6R/IL‐6 complexes, whereas no response was evident in CD4+ T cells from the SF. Down‐regulation of both receptor components in SF T cells could be explained by exposure to high levels of IL‐6. Increased levels of CD130 messenger RNA and protein in synovial tissue CD4+ T cells suggested that CD130 is up‐regulated locally. Among a range of cytokines tested, only IL‐10 induced CD130 expression in T cells.

Conclusion

The inflamed microenvironment in the synovial tissue maintains responsiveness to IL‐6 trans‐signaling through the up‐regulation of CD130 expression in CD4+ T cells, and this process may be driven by IL‐10.
Copy number variations of interleukin‐17F, interleukin‐21, and interleukin‐22 are associated with systemic lupus erythematosus
Authors: Yu Bo , Guan Ming , Peng Yinghui , Shao Yong , Zhang Chao , Yue Xupeng , Zhang Jie , Yang Hong , Zou Hejian , Ye Wencai , Wan Jun , Zhang Wei
Published: September 2011

Objective

Systemic lupus erythematosus (SLE) represents the classic prototype of systemic autoimmune disease. The identification of the Th17 cell subset has provided new understanding regarding the underlying mechanisms of autoimmunity. Copy number variations (CNVS) have been discovered to have phenotypic consequences and are associated with various types of diseases. We undertook this study to explore a possible association between CNVS of Th17 cell–related genes and the risk of SLE.

Methods

We extracted genomic DNA and RNA from 938 SLE patients and 1,017 healthy controls. We examined CNVS of Th17 cell–related genes, including retinoic acid receptor–related orphan nuclear receptor γt, STAT‐3, interleukin‐6 (IL‐6), transforming growth factor β, tumor necrosis factor α, IL‐17A, IL‐17F, IL‐21, IL‐22, IL‐23A, CCL20, and CCR6, and levels of messenger RNA (mRNA) for IL‐17F, IL‐21, and IL‐22.

Results

Genotype and allele frequencies for copy number amplifications of IL‐17F, IL‐21, and IL‐22 were found to be significantly higher in SLE patients than in healthy controls. CNVS of IL‐17F, IL‐21, and IL‐22 had no synergistic contribution to SLE. The mRNA expression of IL‐17F, IL‐21, and IL‐22 in the samples with >2 copies of DNA was significantly higher than that in those with 2 copies of DNA.

Conclusion

Our findings indicate that CNVS of IL‐17F, IL‐21, and IL‐22 are associated with the risk of SLE.
Medical students' attitudes toward the anatomy dissection room in relation to personality
Authors: Plaisant Odile , Courtois Robert , Toussaint Paule Joanne , Mendelsohn Gerald A. , John Oliver P. , Delmas Vincent , Moxham Bernard J.
Published: September 2011

Assessment of the personalities of medical students could enable medical educators to formulate strategies for the best development of academic and clinical competencies. In this article, we focus on the experience of students in the anatomy dissecting room. While there have been many attempts to evaluate the emotional responses of medical students to human cadaveric dissection, there has been no investigation into how different personality traits affect the responses. The main hypothesis tested was that there is a relationship between personality traits and attitudes toward the dissection room. For the present study, a group of French medical students (n = 403; mean age 21.3 ± 1.6; 65.3% female) completed a “Big Five” personality inventory and a questionnaire to assess their attitudes in regard to human dissection. The findings are consistent with our hypothesis, in that we found a relationship between reporting anxiety and four of the “Big Five” dimensions (all except openness). The rated level of anxiety was positively correlated with negative affectivity, more strongly at the beginning than at the end of the course. There were significant gender differences in attitudes toward dissection. The findings are discussed in relation to the possibility of preparing students for the dissecting room experience and also in relation to the students' understanding of mortality issues. Anat Sci Educ. © 2011 American Association of Anatomists.
Assessing the citation impact of books: The role of Google Books, Google Scholar, and Scopus
Authors: Kousha Kayvan , Thelwall Mike , Rezaie Somayeh
Published: September 2011

Citation indictors are increasingly used in some subject areas to support peer review in the evaluation of researchers and departments. Nevertheless, traditional journal‐based citation indexes may be inadequate for the citation impact assessment of book‐based disciplines. This article examines whether online citations from Google Books and Google Scholar can provide alternative sources of citation evidence. To investigate this, we compared the citation counts to 1,000 books submitted to the 2008 U.K. Research Assessment Exercise (RAE) from Google Books and Google Scholar with Scopus citations across seven book‐based disciplines (archaeology; law; politics and international studies; philosophy; sociology; history; and communication, cultural, and media studies). Google Books and Google Scholar citations to books were 1.4 and 3.2 times more common than were Scopus citations, and their medians were more than twice and three times as high as were Scopus median citations, respectively. This large number of citations is evidence that in book‐oriented disciplines in the social sciences, arts, and humanities, online book citations may be sufficiently numerous to support peer review for research evaluation, at least in the United Kingdom.
Understanding image needs in daily life by analyzing questions in a social Q&A site
Authors: Yoon JungWon , Chung EunKyung
Published: September 2011

Compared with search queries, which are usually composed of a few keywords, natural language questions can demonstrate detailed information needs through searchers' richer expressions. This study aims to provide understandings of ordinary people's image needs in their daily life, by analyzing 474 questions obtained from a social question and answer (social Q&A) site. The study found that image needs reflected through the natural language questions contain several components: context of image needs (motive and intervening variables), image attributes (descriptive metadata, syntactic, and semantic attributes), and associated information (information on known/similar/comparative images and related stories). Characteristics of each component of image needs were analyzed, and accordingly image‐indexing guidelines were suggested. Because image needs comprise diverse attributes, a single indexing approach might not support all complex needs for images. Therefore, this study proposes that different indexing approaches should be integrated for enhancing keyword search and browsing effectiveness. Such approaches include descriptive metadata assigned by a creator and/or automatic algorithms, user‐assigned tags (or users' reactions), indexing through associated text, and content‐based image retrieval.
Cytocompatible Poly(ethylene glycol)‐co‐polycarbonate Hydrogels Cross‐Linked by Copper‐Free, Strain‐Promoted Click Chemistry
Authors: Xu Jianwen , Filion Tera M. , Prifti Fioleda , Song Jie
Published: September 2011

Strategies to encapsulate cells in cytocompatible three‐dimensional hydrogels with tunable mechanical properties and degradability without harmful gelling conditions are highly desired for regenerative medicine applications. Here we reported a method for preparing poly(ethylene glycol)‐co‐polycarbonate hydrogels through copper‐free, strain‐promoted azide–alkyne cycloaddition (SPAAC) click chemistry. Hydrogels with varying mechanical properties were formed by “clicking” azido‐functionalized poly(ethylene glycol)‐co‐polycarbonate macromers with dibenzocyclooctyne‐functionalized poly(ethylene glycol) under physiological conditions within minutes. Bone marrow stromal cells encapsulated in these gels exhibited higher cellular viability than those encapsulated in photo‐cross‐linked poly(ethylene glycol) dimethacrylate. The precise control over the macromer compositions, cytocompatible SPAAC cross‐linking, and the degradability of the polycarbonate segments make these hydrogels promising candidates for scaffold and stem cell assisted tissue repair and regeneration.
Fabrication and Functionalization of Hydrogels through “Click” Chemistry
Authors: Yigit Sezin , Sanyal Rana , Sanyal Amitav
Published: September 2011

Hydrogels are crosslinked polymeric materials that play a vital role in many biomedical areas such as drug delivery, sensor technology, and tissue engineering. Increasing demand of these materials for such advanced applications has necessitated the development of hydrogels with complex chemical compositions such as incorporating small molecules and biomolecules that provide the functional attributes. This Focus Review highlights the tremendous impact of click chemistry on the design, synthesis, and functionalization of hydrogels. The high efficiency and fidelity of the click reactions have enabled rapid and modular synthesis of hydrogels with near‐ideal network structures. Efficient incorporation of biomolecular building blocks, such as peptide sequences either during or after the fabrication of hydrogels, have been achieved through various click reactions. Utilization of these efficient reactions has led to the fabrication of many stimuli‐responsive or ′smart′ hydrogels in recent years.
Plume Expansion Dynamics of Matrix‐Assisted Laser Desorption Ionization
Authors: Liang Chi‐Wei , Lee Chih‐Hao , Lee Yuan‐Tseh , Ni Chi‐Kung
Published: September 2011

High‐resolution angular and velocity distributions for neutral analytes (tryptophan and poly‐tryptophan) and matrix (2,4,6‐trihydroxyacetophenon, THAP) are measured by using 355 nm laser desorption. The information suggests that two separate mechanisms dominate the angular and velocity distributions at the beginning and before the end of desorption. A molecular jet‐like isentropic expansion dominates the plume expansion at the beginning of desorption. This only occurs at high surface temperature, thus resulting in a large velocity normal to the surface and a very narrow angular distribution. Most of the analytes are produced under these conditions. Before the end of desorption, the surface temperature decreases and the mechanism of thermal desorption at low vapor pressure takes over. The velocities become small and the angular distribution is close to cosθ. Only a very small amount of analytes are generated under these conditions. Compared to tryptophan, poly‐tryptophan has a much narrower angular distribution, thereby suggesting that it is only produced at the higher surface temperatures.
Impairments in multisensory processing are not universal to the autism spectrum: no evidence for crossmodal priming deficits in Asperger syndrome
Authors: David Nicole , R. Schneider Till , Vogeley Kai , Engel Andreas K.
Published: September 2011

Individuals suffering from autism spectrum disorders (ASD) often show a tendency for detail‐ or feature‐based perception (also referred to as “local processing bias”) instead of more holistic stimulus processing typical for unaffected people. This local processing bias has been demonstrated for the visual and auditory domains and there is evidence that multisensory processing may also be affected in ASD. Most multisensory processing paradigms used social‐communicative stimuli, such as human speech or faces, probing the processing of simultaneously occuring sensory signals. Multisensory processing, however, is not limited to simultaneous stimulation. In this study, we investigated whether multisensory processing deficits in ASD persist when semantically complex but nonsocial stimuli are presented in succession. Fifteen adult individuals with Asperger syndrome and 15 control persons participated in a visual‐audio priming task, which required the classification of sounds that were either primed by semantically congruent or incongruent preceding pictures of objects. As expected, performance on congruent trials was faster and more accurate compared with incongruent trials (crossmodal priming effect). The Asperger group, however, did not differ significantly from the control group. Our results do not support a general multisensory processing deficit, which is universal to the entire autism spectrum. Autism Res 2011,4:383–388. © 2011 International Society for Autism Research, Wiley Periodicals, Inc.
Are thyroid hormone concentrations at birth associated with subsequent autism diagnosis?
Authors: Hoshiko Sumi , Grether Judith K. , Windham Gayle C. , Smith Daniel , Fessel Karen
Published: September 2011

Thyroid hormones substantially influence central nervous system development during gestation. We hypothesized that perturbations of early thyroid profiles may contribute to the development of autism spectrum disorders (ASD). Thyroid pathways could provide a mechanism by which environmental factors that affect the thyroid system may impact autism occurrence or phenotypic expression. We investigated whether thyroxine (T4) levels at birth are associated with subsequent ASD, using two existing California study groups in multivariate analysis. One study group included children born in the San Francisco Bay Area in 1994, with cases identified through the California Department of Developmental Services (DDS) and/or the Kaiser Permanente Medical Care Program of Northern California (244 cases, 266 controls); the other included children born in California in 1995, with cases identified through DDS (310 cases, 518 controls). Matched controls were selected from birth certificate records. This exploratory analysis suggested that infants with very low T4 (<3rd percentile) may have higher ASD risk, although results reached statistical significance only for the 1995 study group (1995: OR = 2.74 (95% CI 1.30–5.75; 1994: OR = 1.71 (95% CI 0.57–5.19). A variety of alternate analyses were conducted with available data, without further resolution of the difference between the two study groups. The results of our study indicate that further studies are warranted to investigate whether thyroid hormone perturbations play a role in the development of ASD by evaluating additional potential confounders and genotype or phenotype in larger studies. Autism Res 2011,4:456–463. © 2011 International Society for Autism Research, Wiley Periodicals, Inc.
Individual Differences in Numeracy and Cognitive Reflection, with Implications for Biases and Fallacies in Probability Judgment
Authors: Liberali Jordana M. , Reyna Valerie F. , Furlan Sarah , Stein Lilian M. , Pardo Seth T.
Published: September 2011

Despite evidence that individual differences in numeracy affect judgment and decision making, the precise mechanisms underlying how such differences produce biases and fallacies remain unclear. Numeracy scales have been developed without sufficient theoretical grounding, and their relation to other cognitive tasks that assess numerical reasoning, such as the Cognitive Reflection Test (CRT), has been debated. In studies conducted in Brazil and in the USA, we administered an objective Numeracy Scale (NS), Subjective Numeracy Scale (SNS), and the CRT to assess whether they measured similar constructs. The Rational–Experiential Inventory, inhibition (go/no‐go task), and intelligence were also investigated. By examining factor solutions along with frequent errors for questions that loaded on each factor, we characterized different types of processing captured by different items on these scales. We also tested the predictive power of these factors to account for biases and fallacies in probability judgments. In the first study, 259 Brazilian undergraduates were tested on the conjunction and disjunction fallacies. In the second study, 190 American undergraduates responded to a ratio‐bias task. Across the different samples, the results were remarkably similar. The results indicated that the CRT is not just another numeracy scale, that objective and subjective numeracy scales do not measure an identical construct, and that different aspects of numeracy predict different biases and fallacies. Dimensions of numeracy included computational skills such as multiplying, proportional reasoning, mindless or verbatim matching, metacognitive monitoring, and understanding the gist of relative magnitude, consistent with dual‐process theories such as fuzzy‐trace theory. Copyright © 2011 John Wiley & Sons, Ltd.
Polymorphisms of stress‐related genes and the risk of nonsyndromic cleft lip with or without cleft palate
Authors: Mostowska Adrianna , Hozyasz Kamil K. , Wojcicka Karolina , Lianeri Margarita , Jagodzinski Pawel P.
Published: September 2011

BACKGROUND: Nonsyndromic cleft lip with or without cleft palate (NCL/P) is a common structural malformation with a complex and multifactorial etiology. It has been shown that maternal psychological stress in the periconceptional period can contribute to an increase in the risk of NCL/P affecting pregnancy. METHODS: Twenty‐four single nucleotide polymorphisms of 11 stress‐related genes (COMT, CRHR1, FKBP5, GABRA6, HSD11β2, MAOA, NPY, NR3C1, SERPINA6, SLC6A4, and TPH2) were investigated in 220 healthy mothers of children with facial clefts and 210 matched controls using restriction fragment‐length polymorphism and high‐resolution melting analysis. RESULTS: We found that polymorphisms in SLC6A4, TPH2, and SERPINA6 appear to be maternal factors increasing the risk of having a child with facial clefts. The closest correlations with NCL/P were found for the SLC6A4 rs2020942 and TPH2 rs10879357 gene variants (odds ratio [OR], 1.720; 95% confidence interval [CI], 1.158–2.553; p = 0.0069; ptrend = 0.0036; and OR, 1.837; 95% CI, 1.226–2.753, p = 0.0030, ptrend = 0.0057; respectively). Moreover, haplotype analysis revealed that several combinations of markers in SLC6A4, TPH2, and SERPINA6 might be significantly associated with the risk of NCL/P affected pregnancies. However, these associations were not statistically significant after correction for multiple testing. CONCLUSION: This study suggests that nucleotide variants of genes encoding components of the hypothalamus‐pituitary‐adrenal axis and serotoninergic system have a role in the etiology of NCL/P in the Polish population. SLC6A4, TPH2, and SERPINA6 might be novel candidate genes for this common congenital anomaly. Birth Defects Research (Part A), 2011. © 2011 Wiley‐Liss, Inc.
The two faces of FBW7 in cancer drug resistance
Authors: Wang Zhiwei , Fukushima Hidefumi , Gao Daming , Inuzuka Hiroyuki , Wan Lixin , Lau Alan W. , Liu Pengda , Wei Wenyi
Published: September 2011

Chemotherapy is an important therapeutic approach for cancer treatment. However, drug resistance is an obstacle that often impairs the successful use of chemotherapies. Therefore, overcoming drug resistance would lead to better therapeutic outcomes for cancer patients. Recently, studies by our own and other groups have demonstrated that there is an intimate correlation between the loss of the F‐box and WD repeat domain‐containing 7 (FBW7) tumor suppressor and the incurring drug resistance. While loss of FBW7 sensitizes cancer cells to certain drugs, FBW7‐/‐ cells are more resistant to other types of chemotherapies. FBW7 exerts its tumor suppressor function by promoting the degradation of various oncoproteins that regulate many cellular processes, including cell cycle progression, cellular metabolism, differentiation, and apoptosis. Since loss of the FBW7 tumor suppressor is linked to drug resistance, FBW7 may represent a novel therapeutic target to increase drug sensitivity of cancer cells to conventional chemotherapeutics. This paper thus focuses on the new functional aspects of FBW7 in drug resistance.
Fabrication of core‐sheath structured fibers for model drug release and tissue engineering by emulsion electrospinning
Authors: Wei Kai , Li Yuan , Mugishima Hikaru , Teramoto Akira , Abe Koji
Published: September 2011

A nano‐brous core‐sheath structured scaffold incorporated with bioactive agents is supposed to promote cell migration, proliferation, and gene expressions through the controllable and sustainable release of bioactive agents from the fibers and the preservation of bioactivity. Here we present a novel and effective emulsion electrospinning method for obtaining fluorescein isothiocyanate‐dextran (FITC‐dextran)/poly(lactic‐co‐glycolic acid) (PLGA) and type I collagen/PLGA fibrous composite scaffolds. Core‐sheath structured fibers with average diameters of 665 nm for FITC‐dextran/PLGA and 567 nm for collagen/PLGA were successfully fabricated. In vitro‐release profile shows sustained release of encapsulated FITC‐dextran from FITC‐dextran/PLGA fibers for as long as 7 weeks. The osteoblastic activity of the collagen/PLGA nanofibrous scaffold was investigated employing the osteoblastic‐like MC3T3‐E1 cell line. The results of the lactate dehydrogenase assay suggested excellent cytocompatibility. Cell proliferation and alkaline phosphatase activity were also ameliorated on this emulsion‐electrospun collagen/PLGA fibrous scaffold. All the results indicated that this composite scaffold could support the early stages of osteoblast behavior as well as the immediate/late stages. The emulsion electrospinning process has potential for application in drug‐release devices and as a 3‐D scaffold in bone regeneration.
Eukaryotic metabolism: Measuring compartment fluxes
Authors: Wahrheit Judith , Nicolae Averina , Heinzle Elmar
Published: September 2011

Metabolic compartmentation represents a major characteristic of eukaryotic cells. The analysis of compartmented metabolic networks is complicated by separation and parallelization of pathways, intracellular transport, and the need for regulatory systems to mediate communication between interdependent compartments. Metabolic flux analysis (MFA) has the potential to reveal compartmented metabolic events, although it is a challenging task requiring demanding experimental techniques and sophisticated modeling. At present no ready‐made solution can be provided to cope with the complexity of compartmented metabolic networks, but new powerful tools are emerging. This review gives an overview of different strategies to approach this issue, focusing on different MFA methods and highlighting the additional information that should be included to improve the outcome of an experiment and associate estimation procedures.