bluuebunny/crossref_metadata_2025 huggingface dataset:
Continuous polymerization of methyl methacrylate in a taylor‐couette reactor. II. influence of fluid dynamics on polymer properties
Authors: Liu Zhen , Kind Matthias
Published: September 2012

In this work, the free radical continuous polymerization of methyl methacrylate (MMA) with the solvent xylene and 2,2‐Azoisobutyronitrile (AIBN) as initiator was studied in a laboratory Taylor‐Couette reactor. It was found that the property of the polymerized product (molecular weight distribution) is affected by the fluid dynamic conditions (mean residence time, rotational speed, diameter of the inner cylinder, and gap width). The weight average molecular weight decreases with an increase of the mean residence time, is strongly dependent on the geometry of the reactor, and was found to be independent on the shear rate in the gap. The width of the molecular weight distribution decreases weakly with increasing residence time, increases with increasing shear rate, and weakly depends on the diameter of the inner cylinder. A correlation was developed to describe the weight‐average molecular weight as a function of the Taylor number and the Damköhler number. This correlation is dimensionless and may be used for scaling‐up purposes. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Effects of thermal treatment on the microstructure and thermal and mechanical properties of poly(lactic acid) fibers
Authors: Gao Chengcheng , Ma Hongxin , Liu Xingxun , Yu Long , Chen Ling , Liu Hongsheng , Li Xiaoxi , Simon George P.
Published: September 2012

The microstructure and thermal and mechanical properties of poly(lactic acid) (PLA) fibers after thermal treatment under both taut and free conditions at different temperatures were studied by differential scanning calorimetry, wide‐angle X‐ray diffraction, microscopy with polarized light, an acoustic method and tensile testing. In particular, the effects of thermal treatment conditions on crystallinity, molecular orientation, and mechanical properties, as well as their interrelationships, were investigated. Both the crystal orientation and crystallinity of the PLA fibers were higher after thermal treatment under taut conditions, even though the molecular orientation was not higher. Thermal treatment relaxed orientated segments, which resulted in increasing crystallinity; however, it did not indicate that the overall molecular alignment of the chains (molecular orientation) would necessarily be high. Tensile strength and elongation were increased with increasing treatment temperature up to 150°C, which corresponded to crystallinity and chain relaxation. The crystallinity detected by XRD, enthalpy measured by DSC, birefringence, and molecular orientation were compared to distinguish the effects of crystallinity, orientation of polymer chains, and crystals. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Investigation on variable shear modulus of magnetorheological elastomer based on natural rubber due to change of fabrication design
Authors: Yoon Ji‐Hyun , Yang In‐Hyung , Jeong Un‐Chang , Chung Kyung‐Ho , Lee Jung‐Youn , Oh Jae‐Eung
Published: September 2012

A magnetorheological elastomer (MRE) is a smart material that has a reversible and variable modulus in a magnetic field. Natural rubber (NR), which has better mechanical properties than other rubbers, was used as the matrix. Carbonyl iron powder (CIP) was selected for the generation of a magnetic field‐dependent modulus in the MREs. The MRE specimens were cured in an anisotropic mold, which was used to induce a magnetic field. SEM images validated the CIP orientation. The shear modulus of the MREs was evaluated under a magnetic field induced by a magnetic flux generator (MFG). An evaluation system was designed that includes an MFG, which is a device that generates a magnetic field via a continuously variable‐induced current to determine the magnetic field‐dependent shear modulus. The variations of the shear modulus were observed with increasing CIP volume fraction and induced current. The experimental results revealed that the maximum variation rate of the shear modulus was 76.3% for 40 vol% of CIP and an induced current of 4 A. Using these results, the appropriate CIP volume fraction and induced current can be proposed as the guidelines in fabrication design of MREs based on NR. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Investigation of the influence of processing conditions on the thermal, rheological and mechanical behavior of polypropylene nanocomposites
Authors: Mattausch H. , Laske S. , Đuretek I. , Kreith J. , Maier G. , Holzer C.
Published: September 2012

The use of polypropylene (PP)‐layered silicate nanocomposite has attracted great interest in the polymer industry over the last years. On one hand, PP is widely used in many fields of applications because of good performance and cost. On the other hand, the major advantage of layered silicate nanofiller in the polymer matrix is the small amount of filler (<5 wt%) needed to enhance various properties such as Young's modulus. The most commonly used layered silicates are organomodified montmorillonite (MMT). In this study, a PP/organoclay nanocomposite, filled with layered silicate Nanofil SE3010 (1 and 5 wt%), provided by Rockwood Additives, USA, was used. The polymer nanocomposites were prepared via melt intercalation in a laboratory kneader. The compatibilizer (PP grafted with maleic acid anhydride) admixture content relative to the organoclay content (1 and 5 wt%) was chosen at a ratio of 1:1 (clay:compatibilizer). The influence of different processing conditions (rotation speed and residence time) on the thermal, rheological, and mechanical properties and the interlayer distance was investigated. It was the target to determine whether a short and intensive or a long and soft process performs better. Different properties prefer different states of dispersion of MMT in the polymer matrix. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Confounding of Big Five Personality Assessments in Emotional Disorders by Comorbidity and Current Disorder
Authors: Spinhoven Philip , van der Does Willem , Ormel Johan , Zitman Frans G. , Penninx Brenda WJH
Published: September 2012

Foremost cross–sectional studies of personality in common mental disorders show similar Big Five trait profiles [i.e. high neuroticism (N), low conscientiousness (C) and low extraversion (E)]. It remains undecided whether this lack of distinct personality profiles is partly due to comorbidity among disorders or contamination by current state. Using data from the Netherlands Study of Depression and Anxiety, we investigated 1046 participants with panic disorder (PD), social anxiety disorder (SAD) and/or major depressive disorder (MDD) and 474 healthy controls. Personality traits at baseline and two–year follow–up were assessed with the NEO–Five Factor Inventory. The Composite International Diagnostic Interview was used to determine the presence of emotional disorders at baseline and at two–year follow–up; the Life Chart Interview determined symptom severity in the month prior to baseline and during follow–up. By analysing pure cases and investigating the effects in remitted cases, PD participants were found to be higher in N, but not lower in E and C than controls. Pure PD participants were also lower in N and higher in E than SAD and MDD participants. Both SAD and MDD participants were characterized by high levels of N and low levels of E, irrespective of comorbidity or current disorder state. Future studies should be more attentive to confounding of personality profiles by comorbidity and state effects. Copyright © 2012 John Wiley & Sons, Ltd.
When Being Discrepant from One's Ideal or Ought Selves Hurts: The Moderating Role of Neuroticism
Authors: Hong Ryan Y. , Triyono Widyasari , Ong Pearlyn S.
Published: September 2012

Self–discrepancy theory posits that people experience emotional consequences when they perceive discrepancies between their actual and possible selves. However, the extent to which people react emotionally to these self–discrepancies (i.e. ideal, ought and undesired) may be a function of individual differences in neuroticism. Across both experimental (Study 1; N = 155) and correlational designs (Study 2; N = 139) involving college students, the authors demonstrated that neuroticism moderated the discrepancy–emotion associations such that high–neuroticism individuals showed elevated depression and anxiety symptoms when their self–discrepancies were activated. The heightened symptoms were maintained over time. Negative repetitive thoughts (i.e. rumination and worry) were examined as potential mediating mechanisms between the discrepancy × neuroticism interaction and symptoms. Partial support was obtained in that rumination mediated between undesired discrepancy × neuroticism interaction and anxious/depressive symptoms. Implications and possible theoretical extensions for self–discrepancy theory are discussed. Copyright © 2012 John Wiley & Sons, Ltd.
Effect of syndiotactic polystyrene on the crystallization behavior of isotactic polypropylene/syndiotactic polystyrene blends with and without β‐nucleating agent
Authors: Zhang Ronghua , Li Robert Kwok Yiu
Published: September 2012

Blends of isotactic polypropylene (PP) and syndiotactic polystyrene (sPS) with and without β‐nucleating agent were prepared using a twin‐screw extruder at 290 °C. Blends of PP/sPS with β‐nucleating agent mainly show β crystalline form, irrespective of high (20 °C min−1) or low (2 °C min−1) previous cooling rates. This suggests that the cooling rates have little effect on the polymorphic composition of PP in PP/sPS blends. The effect of sPS on the crystallization of PP is compared with that of polyamide 6 (PA6). The increase in crystallization temperature of PP is smaller in the presence of sPS than in the presence of PA6; the fold surface free energy of PP/sPS is larger than that of PP/PA6 blends. These results reveal that compared with PA6, sPS has much weaker α‐nucleation effect on the crystallization of PP. The weak α‐nucleation effect of sPS is attributed to the high lattice mismatch between PP and sPS crystals.
Controlling J‐aggregate formation for increased short‐circuit current and power conversion efficiency with a squaraine donor
Authors: Spencer Susan , Hu Harry , Li Qimeng , Ahn Hyo‐Yang , Qaddoura Maher , Yao Sheng , Ioannidis Andronique , Belfield Kevin , Collison Christopher J.
Published: September 2012

A squaraine dye is tested for novel application in a near‐infrared‐active organic photovoltaic cell that is subsequently optimized to obtain a power conversion efficiency of 2.4 ± 0.3%. The optimization utilizes an Alq3 buffer layer and macroscopic structure control through the addition of co‐solvents in the spin‐casting process. Co‐solvent addition increases the amount of aggregates present as measured through linear absorption spectroscopy, and there is a concurrent increase in both efficiency and short‐circuit current. An interpretation of the greatly increased current density is presented that describes how increased J‐aggregation likely increases hole mobility and, as a result, charge separation of the photogenerated excited state. Copyright © 2012 John Wiley & Sons, Ltd.
Borderline personality disorder in suicidal adolescents
Authors: Yen Shirley , Gagnon Kerry , Spirito Anthony
Published: September 2012

The diagnosis of borderline personality disorder (BPD) in adolescents has been controversial. Thus, few studies have examined BPD in suicidal adolescents, even though it is strongly associated with suicidal behaviours in adults. This study examines differences between suicidal adolescents with (n = 47) and without (n = 72) BPD on history and characteristics of suicidal behaviour, Axis I co‐morbidity, affect regulation and aggression. Assessments were completed with both adolescents and parents, and consensus ratings based on best available data were analysed. BPD participants were more likely to have a history of suicide attempts and to have been admitted because of a suicide attempt (vs. suicidal ideation). There were no significant differences in self‐injurious behaviours or degree of suicidal ideation. BPD participants also had more psychiatric co‐morbidity and higher aggression scores but no significant differences in affective dysregulation compared with suicidal adolescents without BPD. Diagnostic stability over 6 months was modest. Our results demonstrate that, compared with other acutely suicidal adolescents, the clinical profile of BPD participants is unique and suggests an increased risk for suicidal behaviours. This extends upon other studies that support the construct validity of BPD during adolescence and suggests that BPD should be considered in suicide risk assessment for adolescents. Copyright © 2012 John Wiley & Sons, Ltd.
Vinyl‐terminated liquid‐crystalline dendrimers based on dendritic polyols and their siloxane‐based elastomers
Authors: Lin Yuteng , Sun Jianzhong
Published: September 2012

A new series of side‐chain liquid‐crystalline dendrimers (LCDs) by grafting vinyl‐terminated phenyl benzoate‐based promesogens to a novel polypropyleneimine‐derived dendritic polyols are reported. Polarized optical microscopy and X‐ray diffraction studies show that both the compounds display a smectic‐A (SmA) mesophase. The second‐generation dendrimer bearing eight‐branched promesogens exhibits a more stable SmA mesophase with a wide mesomorphic temperature range. It is demonstrated that “promoting groups” in the structure of LCD for the enhancement of mesomorphic stability are unnecessary in the case of strong anisotropic interactions. In contrast to conventional LCDs, these two compounds possess reactive vinyl terminals that endow them with the potential for the preparation of polymeric materials. For the first time, a type of thermoset elastomers is explored from LCDs via hydrosilylation crosslinking reaction of vinyl terminals and siloxane crosslinker. Two‐dimensional X‐ray diffraction study indicates that the lamellar structures of original dendrimers are reserved in the elastomer networks. Stress–strain curves reveal that these elastomers exhibit excellent elasticity under successive uniaxial compression. The combination of anisotropic structures of rigid units and elasticity of flexible networks in this novel series of elastomers makes them promising candidates for the application in artificial muscles or cartilages. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
Tunable fluorescence conjugated copolymers consisting of tetraphenylethylene and fluorene units: From aggregation‐induced emission enhancement to dual‐channel fluorescence response
Authors: Shi Jianbing , Wu Yanmei , Sun Shu , Tong Bin , Zhi Junge , Dong Yuping
Published: September 2012

A series of new conjugated polymers PTPExFy, which consist of tetraphenylethylene (TPE) units and fluorene (F) units, have been designed and synthesized by Suzuki cross‐coupling polymerization. The polymers PTPExFy exhibited aggregation‐induced emission enhancement and dual‐channel fluorescence response (DCFR) when they were aggregated in solution, and these properties are related with their TPE‐to‐F ratio in the polymer backbone. For PTPE and PTPE0.5F0.5, the fluorescence emission was enhanced by aggregation when water was added into their THF solutions. For the copolymers PTPE0.3F0.7, PTPE0.2F0.8, and PTPE0.1F0.9, the DCFRs were observed when they were aggregated by adding water into their solution, which can be attributed to the different responses of fluorene segments and TPE segments to aggregation. The fluorene segments have an aggregation‐caused quenching characteristic, whereas the TPE segments have an aggregation‐induced emission characteristic. According to the fluorescence lifetime and quantum yield data of the polymer solutions, we have discovered that the polymer's natural life time increases as its TPE content increases. In the solid film, PTPE0.3F0.7 and PTPE0.2F0.8 showed better quantum yield than other polymers, due to the combination of the excellent fluorescent property of the fluorene groups and the nonplanar conformation of the TPE groups. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
High‐efficiency polymer solar cells based on phenylenevinylene copolymer with BF2‐azopyrrole complex and CN‐PC70BM with solvent additive
Authors: Singh Surya Prakash , Pavan Kumar CH , Sharma G. D. , Mikroyannidis J. A. , Singh Manjeet , Kurchania Rajnish
Published: September 2012

Power conversion efficiency (PCE) of phenylenevinylene‐based copolymer with BF2 azopyrrole complex (PB)/modified PC70BM, that is, CN‐PC70BM bulk heterojunction solar cells improves from 2.16 to 4.90% using a processing additive and drying condition. The results demonstrate that a processing additive and drying condition provides an effective means to control both the surface roughness and finer interpenetrating networks to enhance the exciton dissociation into free charge carriers, charge transportation, and collection. Taking into the account of simple device fabrication process without thermal annealing, the PCE of the polymer solar cell can further improved by chloronapthalene (CN) additive under the fast drying condition. The average carrier lifetimes extracted from the impedance spectra and found to correlate with measured PCEs. At short circuit conditions and illumination, the average charge carrier lifetime was found vary from 16.8 to 32 μs with power conversion efficiencies ranging from 3.0 to 4.9%. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Conjugated polymer‐functionalized graphite oxide sheets thin films for enhanced photovoltaic properties of polymer solar cells
Authors: Lee Rong‐Ho , Huang Jian‐Lun , Chi Chun‐Han
Published: September 2012

In this study, the maleimide‐thiophene copolymer‐functionalized graphite oxide sheets (PTM21‐GOS) and carbon nanotubes (PTM21‐CNT) were developed for polymer solar cell (PSC) applications. The grafting of PTM21‐OH onto the CNT and GO sheets was confirmed using FTIR spectroscopy. PTM21‐CNT and PTM21‐GOS exhibited excellent dispersal behavior in organic solvents. Better thermal stability was observed for PTM21‐CNT and PTM21‐GOS as compared with that for PTM21‐OH. In addition, the optical band gaps of PTM21‐GOS and PTM21‐CNT were lower than that of PTM21‐OH. We incorporated PTM21‐GOS and PTM21‐CNT individually into poly(3‐hexylthiophene) (P3HT)/[6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) blends for use as photoconversion layers of PSCs. Good distributional homogeneity was observed for PTM21‐GOS or PTM21‐CNT in the P3HT/PCBM blend film. The UV–vis absorption peaks of the blend films red‐shifted slightly upon increasing the content of PTM21‐GOS or PTM21‐CNT. The band gap energies and LUMO/HOMO energy levels of the P3HT/PTM21‐GOS and P3HT/PTM21‐CNT blend films were slightly lower than those of the P3HT film. The conjugated polymer‐functionalized PTM21‐GOS and PTM21‐CNT behaved as efficient electron acceptors and as charge‐transport assisters when incorporated into the photoactive layers of the PSCs. PV performance of the PSCs was enhanced after incorporating PTM21‐GOS or PTM21‐CNT in the P3HT/PCBM blend. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013
Predictors of desire for help in oncology outpatients reporting pain or distress
Authors: Clover Kerrie , Kelly Pete , Rogers Kerry , Britton Ben , Carter Gregory Leigh
Published: September 2012

Objective

Although effective treatments for pain and distress are available, many patients do not access them. Improved understanding of patients’ desire for help may improve uptake of services.

Methods

Data were collected as part of the QUICATOUCH screening program at an Australian regional hospital. Patients over threshold for pain were asked if they would like help with their pain and those over threshold for distress were asked if they would like help with their distress. Multivariate logistic regression analyses were conducted to identify independent predictors of desire for help.

Results

Of 305 patients over threshold for pain; 59% wanted help, increasing from 13% at a pain score of one to 90% at a pain score of 10. Of 274 patients over threshold for distress, 30% wanted help, increasing from 21% at a distress score of four to 41% at a distress score of 10. Pain score was the only significant independent predictor of desire for help with pain, with an odds ratio (OR) of 1.50 (95%CI 1.33‐1.70) for every point increase in pain score. Distress score was the only significant independent predictor of desire for help with distress with an OR of 1.29 (95%CI 1.11‐1.50) for every point increase in distress score.

Conclusions

Although desire for help with pain and distress increased with respective symptom intensity, many patients indicated they did not want help with these symptoms. Patient reluctance to seek help may constitute a barrier to realising the full potential of screening programs in reducing pain and distress. Copyright © 2012 John Wiley & Sons, Ltd.
PE‐CVD of Hydrophilic‐COOH Functionalized Coatings on Electrolyte Gated Field‐Effect Transistor Electronic Layers
Authors: Magliulo Maria , Pistillo Bianca Rita , Mulla Mohammad Yusuf , Cotrone Serafina , Ditaranto Nicoletta , Cioffi Nicola , Favia Pietro , Torsi Luisa
Published: September 2012

A plasma deposition (PE‐CVD) process is proposed to functionalize the surface of P3HT organic semiconductor with an hydrophilic coating characterized by carboxyl groups. The functionalized P3HT is employed as electronic active layer in an electrolyte gated organic field‐effect transistor (EGOFET). Nanometric coatings were plasma deposited at the surface of P3HT from glow discharges fed with ethylene and acrylic acid vapors. The surface chemical composition of coated P3HT along with its wettability, have been assessed by means of X‐ray photoelectron spectroscopy and water contact angle. Results show that PE‐CVD is a valid approach to functionalize P3HT surfaces with carboxyl groups, leaving negligible adverse effect on the EGOFET performances. Possibly, chemical or biological species could be immobilized on PE‐CVD‐functionalized EGOFETs, opening to further developments in their use as sensors.

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Nasal and bronchial airway epithelial cell mediator release in children
Authors: Pringle Emily J. , Richardson Helen B. , Miller David , Cornish Daniella S. , Devereux Graham S. , Walsh Garry M. , Turner Steve W.
Published: September 2012

Objective

The present study was designed to test the hypothesis that airway epithelial cell (AEC) mediator release is similar in upper and lower airway AEC in children.

Methods

Nasal and bronchial AEC were collected by brushings from children scheduled for general anesthetic. AEC release of the following mediators was measured: interleukin (IL)‐6, IL‐8, Granulocyte Colony Stimulating Factor (G‐CSF), regulated on activation, normal T‐cell expressed and secreted (RANTES), monocyte chemoattractant protein‐1 (MCP‐1), vascular endothelial growth factor (VEGF), matrix metallo proteinase (MMP)‐9, and tissue inhibitor of metalloproteinases (TIMP)‐1.

Results

AEC were cultured in 34 children, mean age 7.3 years. Release of IL‐6, IL‐8, and G‐CSF was significantly higher in nasal compared with bronchial AEC but nasal and bronchial AEC release of other mediators was not significantly different. Treatment of AEC with IL‐1 β and tumor necrosis factor‐α increased secretion of all mediators. Release of IL‐6 and GSCF remained higher in nasal AEC compared with bronchial AEC following stimulation.

Conclusions

In epidemiological studies, nasal AEC may be a useful surrogate for bronchial AEC for the study of RANTES, MCP‐1, TIMP‐1, and MMP‐9 release in children but bronchial AEC will remain the gold standard. Pediatr Pulmonol. 2012; 47:1215–1225. © 2012 Wiley Periodicals, Inc.
Identification of Cys255 in HIF‐1α as a novel site for development of covalent inhibitors of HIF‐1α/ARNT PasB domain protein–protein interaction
Authors: Cardoso Rosa , Love Robert , Nilsson Carol L. , Bergqvist Simon , Nowlin Dawn , Yan Jiangli , Liu Kevin K.‐C. , Zhu Jing , Chen Ping , Deng Ya‐Li , Dyson H. Jane , Greig Michael J. , Brooun Alexei
Published: October 2012

The heterodimer HIF‐1α (hypoxia inducible factor)/HIF‐β (also known as ARNT‐aryl hydrocarbon nuclear translocator) is a key mediator of cellular response to hypoxia. The interaction between these monomer units can be modified by the action of small molecules in the binding interface between their C‐terminal heterodimerization (PasB) domains. Taking advantage of the presence of several cysteine residues located in the allosteric cavity of HIF‐1α PasB domain, we applied a cysteine‐based reactomics “hotspot identification” strategy to locate regions of HIF‐1α PasB domain critical for its interaction with ARNT. COMPOUND 5 was identified using a mass spectrometry‐based primary screening strategy and was shown to react specifically with Cys255 of the HIF‐1α PasB domain. Biophysical characterization of the interaction between PasB domains of HIF‐1α and ARNT revealed that covalent binding of COMPOUND 5 to Cys255 reduced binding affinity between HIF‐1α and ARNT PasB domains approximately 10‐fold. Detailed NMR structural analysis of HIF‐1α‐PasB‐COMPOUND 5 conjugate showed significant local conformation changes in the HIF‐1α associated with key residues involved in the HIF‐1α/ARNT PasB domain interaction as revealed by the crystal structure of the HIF‐1α/ARNT PasB heterodimer. Our screening strategy could be applied to other targets to identify pockets surrounding reactive cysteines suitable for development of small molecule modulators of protein function.
Effects of Aqueous Extracts of Raw Pu‐erh Tea and Ripened Pu‐Erh Tea on Proliferation and Differentiation of 3T3‐L1 Preadipocytes
Authors: Cao Zhen‐Hui , Yang Hui , He Zhan‐Long , Luo Cheng , Xu Zhi‐Qiang , Gu Da‐Hai , Jia Jun‐Jing , Ge Chang‐Rong , Lin Qiu‐Ye
Published: October 2012

Pu‐erh tea has shown anti‐obesity effects but little is known about its effect on proliferation and differentiation of preadipocytes. This study investigated the effects of the aqueous extracts of raw pu‐erh tea and ripened pu‐erh tea on proliferation and differentiation of murine 3T3‐L1 preadiopocytes. We examined dose and time effects of both aqueous extracts on proliferation of 3T3‐L1 preadipocytes. The contents of triglycerides in cytoplasm and the mRNA expression of critical transcriptional factors involved in differentiation were determined. Cytotoxicity and apoptosis rate of preadipocytes by pu‐erh tea extracts treatment were test for toxic and pro‐apoptotic effects. Both aqueous extracts of pu‐erh tea inhibited the proliferation of 3T3‐L1 preadipocytes at the selected time points. At lower concentration of raw pu‐erh tea extracts (less than 300 µg/ml) and ripened pu‐erh tea extracts (less than 350 µg/ml), no significant cytotoxic and pro‐apoptotic were observed. Ripened pu‐erh tea was more effective with lower IC50 than raw pu‐erh tea. Both extracts suppressed the differentiation and down‐regulated the gene expression of peroxisome proliferator‐activated receptor‐γ and CCAAT/enhancer binding proteins‐α. Therefore, these results indicate that both aqueous extracts of pu‐erh tea can inhibit proliferation and differentiation with ripened pu‐erh tea more potent. Polyphenol rich in both extracts may play a role in the inhibition of proliferation and differentiation of 3T3‐L1 preadipocytes. Copyright © 2012 John Wiley & Sons, Ltd.
High‐resolution isotope‐dilution mass spectrometry using metabolism of isotope‐labeled compounds: Application to drug metabolites
Authors: Vrbanac J. James , Hilgers Allen , Dubnicka Tyson , Shilliday F. Barclay , Humphries David , Hayes Roger N.
Published: September 2012

RATIONALE

Herein we describe a generic quantitative method using high‐resolution, isotope‐dilution (HRID) metabolism of isotope‐labeled compounds and apply it to the analysis of drug metabolites (DMs) in human plasma. Metabolites (drug) in Safety Testing (MIST) application was one goal.

METHODS

Testosterone (T) and diclofenac (D) were chosen for mass defect characteristics. T, [14C]T, [13C3]T, D, [14C]D, and [13C6]D were metabolized separately in vitro to produce test metabolites. Liquid chromatography/radioactivity monitoring (LC/RAM) analysis was used to determine the concentration of the test metabolites in the incubates. The incubates containing 6β‐hydroxy‐T (6βHT), [13C3]6βHT, 4′‐hydroxy‐D (4′HD) and [13C6]4′HD were used to make standard curves. Plasma samples were prepared by 'dilute‐and‐shoot' and analyzed by LC/MS using SCIEX 5000 and Thermo Orbitrap instrumentation.

RESULTS

Human hepatic microsomes and the S9 fraction produced between 2–6 μM β‐hydroxy‐T and 4′‐hydroxy‐D at 60 min starting with 10 μM parent drug as determined by LC/RAM. It was assumed that the amounts of [13C3]6βHT and [13C6]4′HD produced were similar. Dilutions and standard curves were prepared in human plasma. Analysis of the DMs by LC/MS/MS and LC/HRMS exhibited linear responses over a useable range.

CONCLUSIONS

HRID with metabolism of an isotope‐labeled compound reduces the number of analytical variables considerably. Metabolism of the parent drug to DMs represents a simpler alternative quantitative method compared with traditional approaches. The method will have useful applications for evaluating MIST situations. Copyright © 2012 John Wiley & Sons, Ltd.
Determination of alkyl alkylphosphonic acids by liquid chromatography coupled with electrospray ionization tandem mass spectrometry using a dicationic reagent
Authors: Tak Vijay , Purhoit Ajay , Pardasani Deepak , Garg Prabhat , Jain Rajeev , Dubey D. K.
Published: October 2012

A new analytical method based on liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI‐MS/MS) is proposed and validated for the identification and quantification of alkyl alkylphosphonic acids (AAPAs) in aqueous matrices. Retrospective detection and identification of degradation products of chemical warfare agents is important as an indicator of possible use of chemical warfare agents or of environmental contamination. A commercially available solution of 1,9‐nonanediyl‐bis‐(3‐methylimidazolium)bisfluoride (NBMI) allowed detection of AAPAs by positive mode electrospray ionization mass spectrometry by forming an adduct with AAPAs. MS/MS experiments using an ion trap analyzer were carried out for unambiguous identification of AAPAs. Different parameters were optimized in order to obtain both an adequate chromatographic separation and a high sensitivity using experimental design methodology. Quantification was done with matrix‐matched calibration standards of AAPAs. The method was validated in terms of linearity (r2 >0.982), intra‐ and inter‐day precisions (RSD below 15%), and robustness. The method is sensitive enough for the determination of AAPAs in aqueous matrices, with limits of detection in the 1–5 ng mL–1 range and limits of quantification in the 5–20 ng mL–1 range. Finally, the method was successfully applied to determine these AAPAs in aqueous samples provided by the Organization for the Prohibition of Chemical Weapons during 26th and 29th official proficiency tests. The added advantage of this method is identification of low mass range analyte at high mass range, which obviates the background noise at low mass range. Copyright © 2012 John Wiley & Sons, Ltd.
Using transformative boundary objects to create critical engagement in science: A case study
Authors: Tsurusaki Blakely K. , Calabrese Barton Angela , Tan Edna , Koch Pamela , Contento Isobel
Published: October 2012

Teachers are increasingly faced with questions of how to teach the students in diverse classrooms in ways that are responsive to their experiences outside of the classroom. This paper presents a case study of how one 6th‐grade teacher in a midwestern city enacts the Choice, Control, and Change (C3) curriculum, a curriculum based on the concept of dynamic equilibrium (energy in/energy out) in science‐rich and culturally relevant ways. We analyze how she used what we call “transformative boundary objects” to leverage students' cultural knowledge and experiences of food and activity practices and systems to support the learning community in (a) developing an awareness of and trying on the norms and practices of science and (b) legitimizing the values, discourses, and practices of their everyday lives, the first two tenets of Ladson‐Billings (1995a, 1995b) culturally relevant teaching, to transform the traditional discourses and practices of school science. We particularly focus on Ladson‐Billings third tenet, (c), the development of critical consciousness, showing how the teacher uses transformative boundary objects to transform science learning into a context where traditional boundaries between students lives and school science are blurred, and a critical consciousness about how the food system works and its connections to their everyday food choices is supported. © 2012 Wiley Periodicals, Inc. Sci Ed 1–31, 2012
Digital evidence collection for web image access
Authors: Hsieh Che‐Jen , Li Jung‐Shian , Liu Wei‐Cheng
Published: September 2012

As the volume of multimedia data exchanged over the Internet continues to grow, the problem of preventing the unauthorized duplication of copyright‐protected images or the dissemination of undesirable material such as pornographic pictures has become increasingly important. The majority of the images circulated over the Internet are coded in the JPEG format. Thus, the present study proposes a novel digital feature retrieval scheme designed to detect unlawful dissemination of pre‐selected JPEG images. In the proposed approach, the packet‐level features of the target JPEG image are collected in advance and are stored in a feature database. Thereafter, the features of all the packets passing through a nominated router are compared on‐the‐fly with those in the feature database in order to detect any transmissions of the target images. The experimental results show that the proposed packet‐level forensic scheme is far more efficient than existing application‐level schemes. As a result, the proposed scheme provides a viable solution for the background monitoring of JPEG streams over large‐scale network environments such as the Internet in order to detect unlawful transmissions and to compile digital evidence of such transmissions for possible future legal proceedings. Copyright © 2012 John Wiley & Sons, Ltd.
Attribute‐based ring signcryption scheme
Authors: Guo Zhenzhou , Li Mingchu , Fan Xinxin
Published: September 2012

In this paper, we present attribute‐based ring signcryption scheme, which realizes the concept of ring signcryption in the attribute‐based encryption frame firstly. In our system, it allows a user to signcrypt a message by a set of attributes that are chosen without revealing its identity. In additional, we propose the security models and prove the confidentiality and unforgeability of our schemes. We also present the efficiency of our scheme by comparisons. Copyright © 2012 John Wiley & Sons, Ltd.
A practical secure and efficient enterprise digital rights management mechanism suitable for mobile environment
Authors: Chang Chin‐Chen , Chang Shih‐Chang , Yang Jen‐Ho
Published: September 2012

Digital rights management (DRM) is a term for access control technologies that are used by hardware manufacturers, publishers, copyright holders, and individuals to limit the use of digital content and devices. Enterprise digital rights management (E‐DRM) is the application of DRM technology to prevent illegal users from accessing the confidential data of an enterprise. In 2010, Chang et al. proposed an efficient E‐DRM scheme to solve the flaws of Chen's scheme. However, we still found some weaknesses in their scheme. In this article, we propose an improved secure and efficient E‐DRM mechanism based on a one‐way hash function and exclusive‐or. Our mechanism overcomes the weaknesses in the scheme of Chang et al. and also reduces computation costs. In addition, we used BAN logic to show the correctness of our mechanism. Copyright © 2012 John Wiley & Sons, Ltd.
Robust estimation of causal effects of binary treatments in unconfounded studies with dichotomous outcomes
Authors: Gutman R. , Rubin D.B.
Published: September 2012

The estimation of causal effects has been the subject of extensive research. In unconfounded studies with a dichotomous outcome, Y, Cangul, Chretien, Gutman and Rubin (2009) demonstrated that logistic regression for a scalar continuous covariate X is generally statistically invalid for testing null treatment effects when the distributions of X in the treated and control populations differ and the logistic model for Y given X is misspecified. In addition, they showed that an approximately valid statistical test can be generally obtained by discretizing X followed by regression adjustment within each interval defined by the discretized X. This paper extends the work of Cangul et al. 2009 in three major directions. First, we consider additional estimation procedures, including a new one that is based on two independent splines and multiple imputation; second, we consider additional distributional factors; and third, we examine the performance of the procedures when the treatment effect is non‐null. Of all the methods considered and in most of the experimental conditions that were examined, our proposed new methodology appears to work best in terms of point and interval estimation. Copyright © 2012 John Wiley & Sons, Ltd.
Carbon Nanotubes as Plant Growth Regulators: Effects on Tomato Growth, Reproductive System, and Soil Microbial Community
Authors: Khodakovskaya Mariya V. , Kim Bong‐Soo , Kim Jong Nam , Alimohammadi Mohammad , Dervishi Enkeleda , Mustafa Thikra , Cernigla Carl E.
Published: September 2012

Multi‐walled carbon nanotubes (CNTs) can affect plant phenotype and the composition of soil microbiota. Tomato plants grown in soil supplemented with CNTs produce two times more flowers and fruit compared to plants grown in control soil. The effect of carbon nanotubes on microbial community of CNT‐treated soil is determined by denaturing gradient gel electrophoresis and pyrosequencing analysis. Phylogenetic analysis indicates that Proteobacteria and Bacteroidetes are the most dominant groups in the microbial community of soil. The relative abundances of Bacteroidetes and Firmicutes are found to increase, whereas Proteobacteria and Verrucomicorbia decrease with increasing concentration of CNTs. The results of comparing diversity indices and species level phylotypes (OTUs) between samples showed that there is not a significant affect on bacterial diversity.
Emerging In Vitro Models for Safety Screening of High‐Volume Production Nanomaterials under Environmentally Relevant Exposure Conditions
Authors: Kathawala Mustafa Hussain , Xiong Sijing , Richards Mark , Ng Kee Woei , George Saji , Loo Say Chye Joachim
Published: September 2012

The rising production of nanomaterial‐based consumer products has raised safety concerns. Testing these with animal and other direct models is neither ethically nor economically viable, nor quick enough. This review aims to discuss the strength of in vitro testing, including the use of 2D and 3D cultures, stem cells, and tissue constructs, etc., which would give fast and repeatable answers of a highly specific nature, while remaining relevant to in vivo outcomes. These results can then be combined and the overall toxicity predicted with relative accuracy. Such in vitro models can screen potentially toxic nanomaterials which, if required, can undergo further stringent studies in animals. The cyto‐ and phototoxicity of some high‐volume production nanomaterials, using in vitro models, is also reviewed.
An environment for modeling and simulation of message‐passing parallel applications for cloud computing
Authors: Garg Saurabh Kumar , Buyya Rajkumar
Published: September 2012

As Cloud computing is becoming a mainstream platform, it has also become important to understand the implications on customers' applications or systems when deployed on Clouds. Therefore, simulation tools become a critical requirement that not only evaluate the performance of Clouds but also help in developing Cloud computing further. However, current simulation solutions for Clouds do not support many important application paradigms such as message‐passing parallel applications. This limits the usage of these solutions to study the deployment of many scientific applications on Clouds. In this paper, after recognizing the needs and requirements of the Cloud research and development community, we propose a Cloud simulation environment with a scalable network and message‐passing application model that allows accurate evaluation of scheduling and resource provisioning policies and thus helps in optimizing the performance of a Cloud infrastructure. Copyright © 2012 John Wiley & Sons, Ltd.
Eisenbahnüberführung Simmerbach
Authors: Feldmann Markus , Pak Daniel , Kopp Maik , Schillo Nicole , Wirth Tobias , Seidl Günter , Mensinger Martin , Koch Eckart
Published: October 2012

Die VFT‐Rail Pilotbrücke über den Simmerbach wird im Rahmen einer Bauartzulassung durch Feldmessungen überwacht. Die Überwachung umfasst sowohl statische Zuglasten als auch Überfahrten eines Messzuges wie auch des Regelverkehrs. Ein Schwerpunkt der Messungen sind die direkt auf dem Überbau angeordneten Schienenstützpunkte, insbesondere beim Übergang zum Schotterbett am Brückenende. Das Bemessungsverfahren der Verbunddübel der externen Bewehrung des Brückensystems wird anhand von gemessenen Nennspannungen der Stahlprofile überprüft und bewertet.

Railway bridge Simmerbach – Monitoring of the composite dowels and the rail fasteners in the VFT‐Rail system. A monitoring system is installed at the VFT‐Rail pilot bridge over the Simmerbach Valley within the scope of the licensing procedure. It surveys static train loads and dynamic crossings of a test train and of the regular train loads. The focus of the monitoring is set on the rail fastening system of the non‐ballast superstructure near the transition to the normal ballast track. The design concept of the composite dowels implemented in the external reinforcement of the bridge is assessed by measuring the nominal stresses in the steel sections.
Iterative receiver for amplify‐and‐forward relay networks with unknown noise correlation
Authors: Zhang Chao , Tang Suhua , Ren Pinyi
Published: September 2012

For amplify‐and‐forward relay networks, we propose an iterative scheme to estimate channel and detect information symbols for the multi‐antenna destination in spatially correlated noise. The equivalent channel coefficients and noise covariance are estimated by expectation–maximization algorithm. In addition, we discuss the initialization of iteration and analyze the modified Cramér–Rao bound to show the performance of the proposed iterative estimation. Moreover, on the basis of the structure of the proposed iterative estimator, a joint channel estimation and detection receiver is also provided. Finally, simulation results show that the proposed channel estimator and receiver can achieve the optimal performances in amplify‐and‐forward relay networks with unknown noise correlation. Copyright © 2012 John Wiley & Sons, Ltd.
Recurrence relations for toric N = 1 superconformal blocks
Authors: Hadasz Leszek , Jaskólski Zbigniew , Suchanek Paulina
Published: September 2012

Abstract

General 1-point toric blocks in all sectors of N = 1 superconformal field theories are analyzed. The recurrence relations for blocks coefficients are derived by calculating their residues and large Δ asymptotics.
Global analysis of the Higgs candidate with mass ~ 125 GeV
Authors: Ellis John , You Tevong
Published: September 2012

Abstract

We analyze the properties of the Higgs candidate with mass ~ 125 GeV discovered by the CMS and ATLAS Collaborations, constraining the possible deviations of its couplings from those of a Standard Model Higgs boson. The CMS, ATLAS and Tevatron data are compatible with Standard Model couplings to massive gauge bosons and fermions, and disfavour several types of composite Higgs models unless their couplings resemble those in the Standard Model. We show that the couplings of the Higgs candidate are consistent with a linear dependence on particle masses, scaled by the electroweak scale v ~ 246 GeV, the power law and the mass scale both having uncertainties ~ 20%.
Probing for invisible Higgs decays with global fits
Authors: Espinosa J. R. , Grojean C. , Mühlleitner M. , Trott M.
Published: September 2012

Abstract

We demonstrate by performing a global fit on Higgs signal strength data that large invisible branching ratios (Brinv) for a Standard Model (SM) Higgs particle are currently consistent with the experimental hints of a scalar resonance with mass m

h
~ 124 GeV. For this mass, we find Brinv
< 0.64 (95% CL) from a global fit to individual channel signal strengths supplied by ATLAS, CMS and the Tevatron collaborations. Novel tests that can be used to improve the prospects of experimentally discovering the existence of a Brinv with future data are proposed. These tests are based on the combination of all visible channel Higgs signal strengths, and allow us to examine the required reduction in experimental and theoretical errors in this data that would allow a more significantly bounded invisible branching ratio to be experimentally supported. We examine in some detail how our conclusions and method are affected when a scalar resonance at this mass scale has couplings deviating from the SM ones.
Fly motion vision: from optic flow to visual course control
Authors: Borst A.
Published: September 2012

Optic flow-based navigation has been stud­ied extensively in flies, both in tethered as well as in freely flying animals. As neural con­trol elements, the tangential cells of the lobu­la plate seem to play a key role: they are sen­sitive to visual motion, have large receptive fields, and, with their spatial distribution of preferred directions, match the optic flow as elicited during certain types of flight maneu­vers. However, the neural circuit presynaptic to the tangential cells responsible for extract­ing the direction of motion locally has long escaped investigation, due to the small size of the participating neurons. Recent prog­ress was made here by combining genetic si­lencing of candidate neurons with whole-cell patch recording from tangential cells in Dro­sophila. This approach led to the identifica­tion of lamina neurons L1 and L2 providing the input signals to two parallel motion de­tection circuits, specialized for brightness in­crements (L1, ON-pathway) and decrements (L2, OFF-pathway), respectively.
Parenting processes and aggression: The role of self‐control among Turkish adolescents
Authors: Özdemir Yalçın , Vazsonyi Alexander T. , Çok Figen
Published: October 2012

The present study examined the direct and indirect relationships between parenting processes (parental closeness, parental monitoring, and parental peer approval), low self‐control, and aggression. Participants were 546 adolescents aged 14–18 attending state high schools in Turkey. Participants completed a questionnaire that included measures of parenting processes, self‐control, and aggression. Findings provided evidence of both direct and indirect effects of maternal and paternal parenting processes on aggression through low self‐control. Specifically, results showed that maternal closeness, paternal peer approval and both maternal and paternal monitoring were positively and directly related to low self‐control, and indirectly related to aggression through low self‐control. Together, parenting processes and low self‐control explained 21% of the variance in aggression. Implications for self‐control theory and directions for future research are discussed.