bluuebunny/crossref_metadata_2025 huggingface dataset:
Poly(vinyl chloride) hollow‐fiber membranes for ultrafiltration applications: Effects of the internal coagulant composition
Authors: Alsalhy Qusay F. , Rashid Khalid T. , Noori Wallaă A. , Simone S. , Figoli A. , Drioli E.
Published: October 2011

Poly(vinyl chloride) (PVC) hollow‐fiber membranes were spun by a dry/wet phase‐inversion technique from dopes containing 15 wt % PVC to achieve membranes with different pore sizes for ultrafiltration (UF) applications. The effects of the N,N‐dimethylacetamide (DMAc) concentration in the internal coagulant on the structural morphology, separation performance, and mechanical properties of the produced PVC hollow fibers were investigated. The PVC membranes were characterized by scanning electron microscopy, average pore size, pore size distribution, void volume fraction measurements, and solubility parameter difference. Moreover, the UF experiments were conducted with pure water and aqueous solutions of poly(vinyl pyrrolidone) as feeds. The mechanical properties of the PVC hollow‐fiber membranes were discussed in terms of the tensile strength and Young's modulus. It was found that the PVC membrane morphology changed from thin, fingerlike macrovoids at the inner edge to fully spongelike structure with DMAc concentration in the internal coagulant. The effective pores showed a wide distribution, between 0.2 and 1.1 μm, for the membranes prepared with H2O as the internal coagulant and a narrow distribution, between 0.114 and 0.135 μm, with 50 wt % DMAc. The results illustrate that the difference in the membrane performances was dependent on the DMAc concentration. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Chemical interaction between carbon fibers and surface sizing
Authors: Dai Zhishuang , Zhang Baoyan , Shi Fenghui , Li Min , Zhang Zuoguang , Gu Yizhuo
Published: October 2011

Functional groups on the surface of Polyacrylonitrile (PAN)‐based carbon fibers and in fiber surface sizing are likely to react during the curing process of composites, and these reactions could affect the infiltration and adhesion between the carbon fibers and resin. T300B‐3000‐40B fibers and fiber surface sizing were heat‐treated at different temperatures, and the structural changes of both the fiber surface sizing and extracted sizing after heat treatment were investigated by Fourier transform infrared spectroscopy. The results show that the concentration of epoxy groups in both the fiber surface sizing and extracted sizing decreased with increasing heat‐treatment temperature and decreased to zero after treatment at 200°C. The concentration of epoxy groups in the extracted sizing was lower than that of the fiber surface sizing after treatment under the same conditions; this indicated that the rate of reaction between the carbon fibers and fiber surface sizing was higher than the reaction rate of the fiber surface sizing system. X‐ray photoelectron spectroscopy analysis reveals that the content of CO bonds and activated carbon atoms on the surface of the desized treated carbon fibers was the highest when the heat‐treatment temperature was 150°C; this proved the reaction between the carbon fibers and the fiber surface sizing. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Atom transfer radical copolymerization of glycidyl methacrylate and methyl methacrylate
Authors: Neugebauer Dorota , Bury Katarzyna , Wlazło Michał
Published: October 2011

Glycidyl methacrylate (GMA) and methyl methacrylate (MMA) copolymers were synthesized by atom transfer radical polymerization (ATRP). The effect of different molar fractions of GMA, ranging from 0.28 to 1.0, on the polymer polydispersity index (weight‐average molecular weight/number‐average molecular weight) as the indicator of a controlled process was investigated at 70°C, with ethyl 2‐bromoisobutyrate as an initiator and 4,4′‐dinonyl‐2,2′‐bipyridyne (dNbpy)/CuBr as a catalyst system in anisole. The monomer reactivity ratios (r values) were obtained by the application of the conventional linearization Fineman–Ross method (rGMA = 1.24 ± 0.02 and rMMA = 0.85 ± 0.03) and by the Mayo–Lewis method (rGMA = 1.19 ± 0.04 and rMMA = 0.86 ± 0.03). The molecular weights and polydispersities of the copolymers exhibited a linear increase with GMA content. The copolymer compositions were determined by 1H‐NMR and showed a domination of syndiotactic structures. The glass‐transition temperatures (Tg) of the copolymers analyzed by differential scanning calorimetry (DSC) decreased in the range 105–65°C with increasing GMA units. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis and anticoagulant activity of pectin sulfates
Authors: Fan Lihong , Gao Song , Wang Libo , Wu Penghui , Cao Mi , Zheng Hua , Xie Weiguo , Zhou Jinping
Published: October 2011

In this article, we describe the first use of trisulfonated sodium amine as a sulfating reagent for preparing pectin sulfate in aqueous solution. The main reaction parameters that were expected to affect the degree of substitution (DS) were studied. The optimal reaction conditions for the synthesis of pectin sulfate were found to be as follows: the pH of the reaction medium, the reaction temperature, the reaction time, and the ratio of the mole of sodium nitrite (nNaNO2) to the mass of pectin (mpectin) were 6, 60°C, 12 h, and 2.5/190 mol/g, respectively. Pectin and pectin sulfate were characterized by Fourier transform infrared (FTIR) spectroscopy and 13C‐NMR. The FTIR spectra showed the characteristic absorptions of sulfate ester bonds at 1264 and 830 cm−1. Furthermore, the anticoagulant activity of pectin sulfates with different DSs, concentrations, and molecular weights were investigated with respect to the activated partial thromboplastin time (APTT), thrombin time (TT) and prothombin time. The clotting assay indicated that the pectin sulfate prolonged APTT and TT through inhibition of the activity of antithrombin. These results suggest that the introduction of sulfate groups into the pectin structure improved its anticoagulant activity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis of crosslinked polyacrylonitrile via atom transfer radical polymerization with activators regenerated by electron transfer and use of the resin in mercury removal after modification
Authors: Zong Guangxi , Ma Jing , Chen Hou , Wang Chunhua , Ji Naiyi , Liu Delong
Published: October 2011

Crosslinked polyacrylonitrile (PAN) was synthesized with divinylbenzene as the crosslinker with an iron(III)‐mediated atom transfer radical polymerization method with activators regenerated by electron transfer. The polymerization exhibited first‐order kinetics with respect to the polymerization time. Hydroxylamine hydrochloride (NH2OH·HCl) was used to modify the cyano groups of the crosslinked PAN to obtain amidoxime (AO) groups. The AO‐crosslinked PAN was used to remove Hg(II). The optimum pH, adsorption kinetics, and adsorption isotherms were investigated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Fractional thermoelectric viscoelastic materials
Authors: Ezzat Magdy A. , El‐Karamany Ahmed S.
Published: October 2011

A new mathematical model of thermoelectro viscoelasticity theory was constructed in the context of a new consideration of heat conduction with fractional order. The state space approach developed earlier by Ezzat was adopted for the solution of a one‐dimensional problem in the presence of heat sources. The Laplace‐transform technique was used. A numerical method was employed for the inversion of the Laplace transforms. According to the numerical results and their graphs, a conclusion about the new theory was constructed. Some comparisons are shown in figures to estimate the effect of the fractional order parameter on all of the studied fields. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Crystallization kinetics of poly (L‐lactic acid)/montmorillonite nanocomposites under isothermal crystallization condition
Authors: Hwang Jiunn‐Jer , Huang Su‐Mei , Liu Hsin‐Jiant , Chu Hawn‐Chung , Lin Li‐Huei , Chung Chen‐Sheng
Published: October 2011

Poly(L‐lactic acid)/o‐MMT nanocomposites, incorporating various amounts of organically modified montmorillonite (o‐MMT; 0–10 wt %), were prepared by solution intercalation. The montmorillonite (MMT) was organically modified with dilauryl dimethyl ammonium bromide (DDAB) by ion exchange. Transmission electron microscopy (TEM) and X‐ray diffraction (XRD) reveal that the o‐MMT was exfoliated in a poly(L‐lactic acid), (PLLA) matrix. A series of the test specimens were prepared and subjected to isothermal crystallization at various temperatures (T1–T5). The DSC plots revealed that the PLLA/o‐MMT nanocomposites that were prepared under nonisothermal conditions exhibited an obvious crystallization peak and recrystallization, but neat PLLA exhibited neither. The PLLA/o‐MMT nanocomposites (2–10 wt %) yielded two endothermic peaks only under isothermal conditions at low temperature (T1), and the intensity of Tm2 (the higher melting point) was proportional to the o‐MMT content (at around 171°C). The melting point of the test samples increased with the isothermal crystallization temperature. In the Avrami equation, the constant of the crystallization rate (k) was inversely proportional to the isothermal crystallization temperature and increased with the o‐MMT content, especially at low temperature (T1). The Avrami exponent (n) of the PLLA/o‐MMT nanocomposites (4–10 wt %) was 2.61–3.56 higher than that of neat PLLA, 2.10–2.56, revealing that crystallization occurred in three dimensions. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis of clay‐dispersed poly(styrene‐co‐methyl methacrylate) nanocomposite via miniemulsion atom transfer radical polymerization: A reverse approach
Authors: Khezri Khezrollah , Haddadi‐Asl Vahid , Roghani‐Mamaqani Hossein , Salami‐Kalajahi Mehdi
Published: October 2011

Poly(styrene‐co‐methyl methacrylate) nanocomposites were synthesized using reverse atom transfer radical polymerization (RATRP) in miniemulsion. Cetyltrimethylammonium bromide (CTAB) as a cationic surfactant applicable at higher temperatures was used for miniemulsion stabilization. Successful RATRP was carried out by using 4,4′‐dinonyl‐2,2′‐bipyridine (dNbPy) as ligand. Monodispersed droplets and particles with sizes in the range of 200 nm were revealed by dynamic light scattering (DLS). Conversion and molecular weight study was carried out using gravimetry and size exclusion chromatography (SEC) respectively. By adding clay content, a decrease in the conversion and molecular weight and an increase in the PDI value of the nanocomposites are observed. Thermal stability of the nanocomposites in comparison with the neat copolymer is revealed by thermogravimetric analysis (TGA). Increased Tg values by adding clay content was also obtained using differential scanning calorimetry (DSC). Scanning electron microscopy (SEM) images of the nanoconposite with 1 wt % of nanoclay loading, display monodispersed spherical particles with sizes in the range of ∼ 200 nm. SEM findings are more compiled with dynamic light scattering (DLS) results. Well‐dispersed exfoliated clay layers in the polymer matrix of the nanocomposite with 1 wt % nanoclay loading is confirmed by transmission electron microscopy (TEM) images and X‐ray diffraction (XRD) data. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis of poly(N‐isopropylacrylamide) under atmospheric pressure plasma conditions
Authors: Spridon Delia , Curecheriu Lavinia , Dobromir Marius , Dumitrascu Nicoleta
Published: October 2011

This work is focused on obtaining and characterizing thin films of a certain thermosensitive polymer, i.e., poly(N‐isopropylacrylamide). To obtain such polymers dielectric barrier discharge plasma working at atmospheric pressure in plan–plan geometry was used. The plasma parameters were monitored during polymerization reaction by its electrical and optical signals. The obtained films were analyzed by different techniques such as X‐photoelectron spectroscopy, Fourier transform infrared spectroscopy, atomic force microscopy, contact angle, impedance spectroscopy measurements, and light interferometry for thickness measurements. Chemical analyses of obtained films showed that they sort well with the polymers obtained by other methods in literature. It has been proved that plasma polymerized films have a superhydrophilic character at room temperature, the measured contact angle being around 13°, the lower critical solution temperature was also identified at about 30–31°C. The films' thickness for a 10‐min duration deposition was 400 nm. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Production of melamine fortified urea‐formaldehyde resins with low formaldehyde emission
Authors: Paiva Nádia T. , Henriques Ana , Cruz Paulo , Ferra João M. , Carvalho Luisa H. , Magalhães Fernão D.
Published: October 2011

Melamine can be incorporated in the synthesis of urea‐formaldehyde (UF) resins to improve performance in particleboards (PB), mostly in terms of hydrolysis resistance and formaldehyde emission. In this work, melamine‐fortified UF resins were synthesized using a strong acid process. The best step for melamine addition and the effect of the reaction pH on the resin characteristics and performance were evaluated. Results showed that melamine incorporation is more effective when added on the initial acidic stage. The condensation reaction pH has a significant effect on the synthesis process. A pH below 3.0 results on a very fast reaction that is difficult to control. On the other hand, with pH values above 5.0, the condensation reaction becomes excessively slow. PBs panels produced with resins synthesized with a condensation pH between 4.5 and 4.7 showed good overall performance, both in terms of internal bond strength and formaldehyde emissions. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effects of an amphoteric copolymer on the properties of cementitious materials
Authors: Sheen Yeong‐Nain , Ho Chung‐Da , Weng Wei‐Hung , Hsu Kung‐Chung
Published: October 2011

The effects of an amphoteric copolymer, poly(acrylamide‐co‐(2‐(3‐carboxyacryloyloxy)‐N‐(carboxymethyl)‐N,N‐dimethyl‐ethanaminium) (PAC) on the properties of cement pastes or mortars were investigated. PAC was prepared from acrylamide and 2‐(3‐carboxy‐acryloyloxy)‐N‐(carboxymethyl)‐N,N‐dimethylethanaminium (CAC) through free radical polymerization. The results indicate that the presence of the polymer delayed the setting of cement pastes; it also reduced the water demand so that the resulting mortars showed improved compressive strength and reduced length change. PAC with about 16.7% CAC and a weight‐average molecular weight of about 5 × 104 was effective in promoting the material properties of mortars. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Electro‐optical properties of polymer‐dispersed liquid crystal prepared by controlled graft living radical polymerization
Authors: Qin Ailin , Zhang Yuliang , Wang Yinghan
Published: October 2011

Living graft macromolecule has been prepared through reversible addition‐fragmentation chain transfer (RAFT) living radical polymerization in one step. Then, it was used to make polymer‐dispersed liquid crystal (PDLC) by controlling the mole ratio of styrene (St) to 1,6‐hexanediol diacrylate (HDDA) and adjusting the content of prepared graft macromolecule. The results showed that electro‐optical properties of PDLC have been optimized. Different concentration of living graft macromolecule and different mole ratio of St/HDDA led to substantial improvement of driving voltage (threshold voltage and saturation voltage) and memory effect of PDLC simultaneously. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Thermal aging on mechanical properties and crosslinked network of natural rubber/zinc Dimethacrylate composites
Authors: Xu Chuanhui , Chen Yukun , Huang Jing , Zeng Xingrong , Ding Jianping
Published: October 2011

This article dealt with the relationship between mechanical properties and crosslinked networks of natural rubber (NR) reinforced by zinc dimethacrylate (ZDMA) after thermal aging. After thermal aging at the present experimental conditions, the covalent crosslink density showed a decrease all the time, whereas the ionic crosslink density was stable at 80°C but decreased at a higher temperature. The decrease in the total crosslink density after aging indicates the degradation of the crosslinked network. However, an experimental phenomenon observed was that the tensile strength and tear strength increased in a certain degree after aging at 80°C or at a 100°C for a short time. In addition, the thermal stability of the NR/ZDMA composite was evaluated by thermal gravimetric analysis. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Mixtures of poly(vinyl chloride) and copolyesters based on ε‐caprolactone and L‐lactide: Miscibility, thermal stability, and weathering resistance
Authors: Brožek Jiří , Žídková Markéta , Malinová Lenka , Kalousková Radka
Published: October 2011

Properties of the blends of Poly(vinyl chloride) (PVC) and poly(ε‐caprolactone) (PCLO) and copolyesters based on ε‐caprolactone and L‐lactide (LLA) prepared by rolling were studied. Incorporating the LLA units into the structure of PCLO the content of the crystalline phase was controlled. Miscibility of the blends was assessed using DMA, and basic mechanical properties were correlated with the type and content of the polymer plasticizer. The PVC blends containing up to 20 wt parts polyesters were miscible. The presence of the LLA units in the copolyester influenced negatively the thermal stability. On the other hand even small content of copolyester in the blend enhanced the resistivity against aging. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Solvent‐free diazotization–azidation of aryl amine using a polymer‐supported azide ion
Authors: Karimi Zarchi Mohammad Ali , Nabaei Rahman
Published: October 2011

Crosslinked poly (4‐vinylpyridine)‐supported azide ion was used as an effective azidating agent for deazodination of stable arenediazonium salts under solvent‐free conditions in high yields. The diazotization of aromatic amines was prepared by grinding the combination of an aromatic amine, sodium nitrite (NaNO2), p‐toluene sulfonic acid (p‐TsOH), and 0.2 mL H2O in a mortar. Grinding was continued for deazodination–azidation of the obtained relatively stable diazonium salts, with addition of crosslinked poly (4‐vinylpyridine) supported azide ion to obtain the corresponding aryl azides. The spent polymeric reagents can usually be removed and regenerated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effect of the compatibilizer on the morphology and properties of dynamically cured PP/POE/epoxy blends
Authors: Jiang Xue Liang , Fan Yihong
Published: October 2011

Dynamic vulcanization was successfully applied to epoxy resin reinforced polypropylene (PP)/ethylene‐octene copolymer (POE) blends, and the effects of different compatibilizers on the morphology and properties of dynamically cured PP/POE/epoxy blends were studied. The results show that dynamically cured PP/POE/epoxy blends compatibilized with maleic anhydride‐grafted polypropylene (MAH‐g‐PP) have a three‐phase structure consisting of POE and epoxy particles dispersed in the PP continuous phase, and these blends had improved tensile strength and flexural modulus. While using maleic anhydride‐grafted POE (MAH‐g‐POE) as a compatibilizer, the structure of the core‐shell complex phase and the PP continuous phase showed that epoxy particles could be embedded in MAH‐g‐POE in the blends, and gave rise to an increase in impact strength, while retaining a certain strength and modulus. DSC analysis showed that the epoxy particles in the blends compatibilized with MAH‐g‐PP were more efficient nucleating agents for PP than they were in the blends compatibilized with MAH‐g‐POE. WAXD analysis shows that compatibilization do not disturb the crystalline structure of PP in the blends. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effect of curing temperature on properties and solvent welding strength of ovalbumin
Authors: Lin Yi‐chuan , Chang Z. C. , Lin C. B. , Shen Chien‐Chin , Su Yen‐Li
Published: October 2011

Effect of curing temperature on properties of ovalbumin has been investigated. Functional basis, crosslinking degree, tensile strength, and hardness increases with rising curing temperature. The increase of visible transmittance and the decrease of absorption accompany with increasing wavelength. The absorptive peak shows at 440–450 nm and the wavelength of the absorptive peak increases with the rising curing temperature. The relationship of joint strength with solvent welded joints of ovalbumin to their microstructure is also investigated. Ovalbumin can promote joint strength after the treatment of distilled water and curing. Comparing joint strength with fracture morphology, the smoother fracture surface morphology is related to the maximum tensile and shear joint strength, respectively. The joint strength is increasing with curing temperature and compressive stress, and the joint strength of treatment with 150°C curing temperature and 0.12 kgf/mm2 compressive stresses are larger than its original tensile fracture strength of cured ovalbumin at same curing temperature. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Assessing Damage to Archaeological Artefacts in Compacted Soil Using Microcomputed Tomography Scanning
Authors: McBride R. A. , Mercer G. D.
Published: October 2011

This laboratory study investigated the susceptibility of subsurface archaeological ecofacts/artefacts to incidental damage from utility construction activities, as it pertains to the cultural heritage aspects of environmental impact assessment and municipal planning. The research objective was to use X‐ray microcomputed tomography (micro‐CT) imaging to non‐destructively determine the nature and extent of any damage inflicted on a range of ecofact and artefact types (authentic and replica) embedded in repacked, plastic clay soil by pure soil strain at variable levels of static load compactive effort up to 600 kPa. Uniaxial soil compression testing and micro‐CT imaging were combined procedurally to meet this objective. It was concluded that lithic artefacts were largely immune to damage from stresses up to 600 kPa due to their high strength properties, while moderately fragile ecofacts (replica charred maize kernels) exhibited evidence of dimensional distortion, but not of breakage. Very fragile ecofacts (unionid freshwater clam shells) showed dimensional distortion and minor structural damage at lower stresses (50 and 100 kPa), but significant breakage and fragmentation at higher stresses (300 and 600 kPa). Overall, the micro‐CT technique was shown to be useful in monitoring and describing any breakage or morphometric distortion in a wide range of test ecofacts/artefacts compressed in a clay‐rich soil matrix. However, earthen artefacts, such as terra cotta pottery sherds, were found to be problematic using the micro‐CT imaging technique for this application due to similarities in the densities of the ceramic sherds and the surrounding compressed soil matrix. Copyright © 2011 John Wiley & Sons, Ltd.
Use of atorvastatin in systemic lupus erythematosus in children and adolescents
Authors: Schanberg L. E. , Sandborg C. , Barnhart H. X. , Ardoin S. P. , Yow E. , Evans G. W. , Mieszkalski K. L. , Ilowite N. T. , Eberhard A. , Imundo L. F. , Kimura Y. , von Scheven E. , Silverman E. , Bowyer S. L. , Punaro M. , Singer N. G. , Sherry D. D. , McCurdy D. , Klein‐Gitelman M. , Wallace C. , Silver R. , Wagner‐Weiner L. , Higgins G. C. , Brunner H. I. , Jung L. , Soep J. B. , Reed A. M. , Provenzale J. , Thompson S. D. ,   Atherosclerosis Prevention in Pediatric Lupus Erythematosus Investigators
Published: October 2011

Objective

Statins reduce atherosclerosis and cardiovascular morbidity in the general population, but their efficacy and safety in children and adolescents with systemic lupus erythematosus (SLE) are unknown. This study was undertaken to determine the 3‐year efficacy and safety of atorvastatin in preventing subclinical atherosclerosis progression in pediatric‐onset SLE.

Methods

A total of 221 participants with pediatric SLE (ages 10–21 years) from 21 North American sites were enrolled in the Atherosclerosis Prevention in Pediatric Lupus Erythematosus study, a randomized double‐blind, placebo‐controlled clinical trial, between August 2003 and November 2006 with 36‐month followup. Participants were randomized to receive atorvastatin (n = 113) or placebo (n = 108) at 10 or 20 mg/day depending on weight, in addition to usual care. The primary end point was progression of mean‐mean common carotid intima‐media thickening (CIMT) measured by ultrasound. Secondary end points included other segment/wall‐specific CIMT measures, lipid profile, high‐sensitivity C‐reactive protein (hsCRP) level, and SLE disease activity and damage outcomes.

Results

Progression of mean‐mean common CIMT did not differ significantly between treatment groups (0.0010 mm/year for atorvastatin versus 0.0024 mm/year for placebo; P = 0.24). The atorvastatin group achieved lower hsCRP (P = 0.04), total cholesterol (P < 0.001), and low‐density lipoprotein (P < 0.001) levels compared with placebo. In the placebo group, CIMT progressed significantly across all CIMT outcomes (0.0023–0.0144 mm/year; P < 0.05). Serious adverse events and critical safety measures did not differ between groups.

Conclusion

Our results indicate that routine statin use over 3 years has no significant effect on subclinical atherosclerosis progression in young SLE patients; however, further analyses may suggest subgroups that would benefit from targeted statin therapy. Atorvastatin was well tolerated without safety concerns.
Tetracene Dicarboxylic Imide and Its Disulfide: Synthesis of Ambipolar Organic Semiconductors for Organic Photovoltaic Cells
Authors: Okamoto Toshihiro , Suzuki Tsuyoshi , Tanaka Hideyuki , Hashizume Daisuke , Matsuo Yutaka
Published: October 2011

We have designed and synthesized a new donor/acceptor‐type tetracene derivative by the introduction of dicarboxylic imide and disulfide groups as electron‐withdrawing and ‐donating units, respectively. The prepared compounds, tetracene dicarboxylic imide (TI) and its disulfide (TIDS) have high chemical and electrochemical stability as well as long‐wavelength absorptions of up to 886 nm in the thin films. The crystal packing structure of TIDS molecules features face‐to‐face π‐stacking, derived from dipole–dipole interactions. Notably, TIDS exhibited ambipolar properties of both electron‐donating and ‐accepting natures in p–n and p–i–n heterojunction organic thin‐film photovoltaic devices. Accordingly, TI and TIDS are expected to be promising compounds for designing new organic semiconductors.
Cloud modeling of a network region in Hα
Authors: Bostancı Z.F.
Published: October 2011

In this paper, we analyze the physical properties of dark mottles in the chromospheric network using two‐dimensional spectroscopic observations in Hα obtained with the Göttingen Fabry‐Perot Spectrometer in the Vacuum Tower Telescope at the Observatory del Teide, Tenerife. Cloud modeling was applied to measure the mottles' optical thickness, source function, Doppler width, and line‐of‐sight velocity. Using these measurements, the number density of hydrogen atoms in levels 1 and 2, total particle density, electron density, temperature, gas pressure, and mass density parameters were determined with the method of Tsiropoula & Schmieder (1997). We also analyzed the temporal behaviour of a mottle using cloud parameters. Our result shows that it is dominated by 3 minute signals in source function, and 5 minutes or more in velocity (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Lunisolar effect on the trigger of earthquakes
Authors: Gackstatter F.H. , Gackstatter C.F.
Published: October 2011

Dealing with moon theory and tidal dynamics and checking lists of earthquake data one can take the following two observations: 1) The first extreme proxigean spring tide in the new millennium happened on 2005 January 10, in new moon phase, and half a synodic month earlier, when the Moon was full on 2004 December 26, the Christmas Tsunami was triggered in the Indian Ocean. The next extreme tide in new moon phase will occur after one Saros cycle, on 2023 January 21. 2) The second observation is connected with the lunar evection anomaly. The time between the Whitsun Quake in China on 2008 May 12 and the Christmas Tsunami amounts to 1233 days. On the other hand, three lunar evectional cycles take 3 × Ue = 3 × 411.8 = 1235 days. These observations hint at lunisolar structures in the earthquake distribution. In the present treatise we will reveal such structures by composing lunisolar ephemerides and earthquake Tables. In particular, we use Student's t‐test and show that there is a significant relationship between the beat period Ue and the earthquake statistics (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Features of a comet nucleus: The case of 103P/Hartley 2
Authors: Gronkowski P. , Sacharczuk Z. , Topolewicz S.
Published: October 2011

In the paper two chosen features of the comet 103P/Hartley 2 are studied. The first one are ‘cometary geysers’ which have been recorded by the camera on Deep Impact spacecraft. The numerical calculations related with this phenomenon have been carried out for large number of values of probable cometary characteristics. Our calculations confirm the assumption what also has been observed by NASA's scientists that the jets of carbon dioxide from the geysers are able to lift large chunks of water ice from the comet. The second discussed feature of the comet 103P/Hartley 2 is the lack of impact holes on the surface of its nucleus. The expected rate of impact holes on the surface of the nucleus of 103P/Hartley 2 is discussed. These holes could be the product of impacts between this comet and other small bodies orbiting in the main asteroid belt. The probability of such impacts, the total number of expected perceptible holes and changes in the luminosity of the comet caused by collisions are examined. We conclude that indeed the number of visible holes on its surface should be negligible (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the design of the PEPSI spectropolarimeter for the LBT
Authors: Ilyin I. , Strassmeier K.G. , Woche M. , Dionies F. , Di Varano I.
Published: October 2011

We present the design concept of the spectropolarimeter for the high‐resolution echelle spectrograph PEPSI tobe installed at the 2 × 8.4 m Large Binocular Telescope (LBT) in Arizona. We discuss the optical key elements, the principles of operations of the instrument and its instrumental polarization effects (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Scaling factors: Transcription factors regulating subcellular domains
Authors: Mills Jason C. , Taghert Paul H.
Published: October 2011

Developing cells acquire mature fates in part by selective (i.e. qualitatively different) expression of a few cell‐specific genes. However, all cells share the same basic repertoire of molecular and subcellular building blocks. Therefore, cells must also specialize according to quantitative differences in cell‐specific distributions of those common molecular resources. Here we propose the novel hypothesis that evolutionarily‐conserved transcription factors called scaling factors (SFs) regulate quantitative differences among mature cell types. SFs: (1) are induced during late stages of cell maturation; (2) are dedicated to specific subcellular domains; and, thus, (3) allow cells to emphasize specific subcellular features. We identify candidate SFs and discuss one in detail: MIST1 (BHLHA15, vertebrates)/DIMM (CG8667, Drosophila); professional secretory cells use this SF to scale up regulated secretion. Because cells use SFs to develop their mature properties and also to adapt them to ever‐changing environmental conditions, SF aberrations likely contribute to diseases of adult onset.
PRDM proteins: Important players in differentiation and disease
Authors: Fog Cathrine K. , Galli Giorgio G. , Lund Anders H.
Published: October 2011

The PRDM family has recently spawned considerable interest as it has been implicated in fundamental aspects of cellular differentiation and exhibits expanding ties to human diseases. The PRDMs belong to the SET domain family of histone methyltransferases, however, enzymatic activity has been determined for only few PRDMs suggesting that they act by recruiting co‐factors or, more speculatively, confer methylation of non‐histone targets. Several PRDM family members are deregulated in human diseases, most prominently in hematological malignancies and solid cancers, where they can act as both tumor suppressors or drivers of oncogenic processes. The molecular mechanisms have been delineated for only few PRDMs and little is known about functional redundancy within the family. Future studies should identify target genes of PRDM proteins and the protein complexes in which PRDM proteins reside to provide a more comprehensive understanding of the biological and biochemical functions of this important protein family.
Increasing Teachers' Use of a 1:1 Praise‐to‐Behavior Correction Ratio to Decrease Student Disruption in General Education Classrooms
Authors: Pisacreta Jeffrey , Tincani Matthew , Connell James E. , Axelrod Saul
Published: October 2011

Contingent, behavior‐specific praise is universally recommended as an effective tool to increase students’ academic achievement and proscocial behavior. Despite this recommendation, little research has examined the effects of training teachers to increase their praise‐to‐behavior correction ratio in classroom settings. This study evaluated the effects of training teachers to provide a 1:1 ratio of praise‐to‐behavior correction to decrease student disruption in three general‐education classrooms. Three urban middle‐school general‐teachers who exhibited very low rates of praise participated in the study. Teachers received training, including modeling and performance feedback, to achieve a 1:1 ratio of praise‐to‐behavior correction administered within a multiple‐baseline across participants design. Results demonstrated that (a) the teachers were able to achieve and maintain a 1:1 praise‐to‐behavior correction ratio; (b) a reduction in student disruption coincided with teachers’ use of a 1:1 praise‐to‐behavior correction ration; and (c) two teachers evidenced moderate levels of generalization to classrooms where no training took place. Implications for practitioners and future research are discussed. Copyright © 2011 John Wiley & Sons, Ltd.
Purification and characterization of intracellular and extracellular α‐glucosidases from Geobacillus toebii strain E134
Authors: Cihan Arzu Coleri , Benli Mehlika , Cokmus Cumhur
Published: October 2011

Two different α‐glucosidase‐producing thermophilic E134 strains were isolated from a hot spring in Kozakli, Turkey. Based on the phenotypic, phylogenetic and chemotaxonomic evidence, the strain was proposed to be a species of G. toebii. Its thermostable exo‐α‐1,4‐glucosidases also were characterized and compared, which were purified from the intracellular and extracellular fractions with estimated molecular weights of 65 and 45 kDa. The intracellular and extracellular α‐glucosidases showed optimal activity at 65 °C, pH 7·0, and at 70 °C, pH 6·8, with 3·65 and 0·83 Km values for the pNPG substrate, respectively. Both enzymes remained active over temperature and pH ranges of 35–70 °C and 4·5–11·0. They retained 82 and 84% of their activities when incubated at 60 °C for 5 h. Their relative activities were 45–75% and 45–60% at pH 4·5 and 11·0 values for 15 h at 35 °C. They could hydrolyse the α‐1,3 and α‐1,4 bonds on substrates in addition to a high transglycosylation activity, although the intracellular enzyme had more affinity to the substrates both in hydrolysis and transglycosylation reactions. Furthermore, although sodium dodecyl sulfate behaved as an activator for both of them at 60 °C, urea and ethanol only increased the activity of the extracellular α‐glucosidase. By this study, G. toebii E134 strain was introduced, which might have a potential in biotechnological processes when the conformational stability of its enzymes to heat, pH and denaturants were considered. Copyright © 2011 John Wiley & Sons, Ltd.
Catalytic Aminolysis (Amide Formation) from Esters and Carboxylic Acids: Mechanism, Enhanced Ionic Liquid Effect, and its Origin
Authors: de Oliveira Vanda Maria , Silva de Jesus Richard , Gomes Alexandre F. , Gozzo Fábio C. , Umpierre Alexandre P. , Suarez Paulo A. Z. , Rubim Joel C. , Neto Brenno A. D.
Published: October 2011

This paper describes the use of imidazolium‐based ionic liquids {1‐n‐butyl‐3‐methylimidazolium tetrafluoroborate [BMI‐BF4], 1‐n‐butyl‐3‐methylimidazolium hexafluorophosphate [BMI‐PF6], and 1‐n‐butyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide [BMI‐NTf2]} as efficient supports for Lewis and Brønsted acids ,which are promoters of the aminolysis of some esters, fatty acids, and fatty acid esters (among others) to form amide derivatives. Some esters and carboxylic acids were tested to demonstrate the generality of the methodology, and the corresponding amides were obtained in high yields. Recycling reactions (at least eight reuses) without a notable loss in activity could be performed by using CdO and SnCl2 as catalysts in BMI‐NTf2 as the ionic medium. Brønsted acids, such as H2SO4 and HCl, were also tested with impressive results; however, it was not possible to perform recycling reactions because of catalyst leaching. The same was true when using BF3⋅OEt2 as the catalyst. Mechanistic insights and the ionic‐liquid effect were investigated by using 13C{1H} NMR spectroscopy, which showed that there is a strong interaction of the imidazolium cation with the CO and CC bonds of methyl oleate, most likely through CH⋅⋅⋅π interactions, π‐stacking interactions, and ion‐pair formation in the presence of a metal catalyst. Electrospray ionization–quadrupole time‐of‐flight experiments allowed a better understanding of the reaction mechanism. The results could explain the enhanced ionic‐liquid effect on the stabilization of the formed intermediates, which facilitated the amide bond formation.
Gold Nanoparticles Stabilized by Thioether Dendrimers
Authors: Hermes Jens Peter , Sander Fabian , Peterle Torsten , Urbani Raphael , Pfohl Thomas , Thompson Damien , Mayor Marcel
Published: October 2011

Ligand‐stabilized gold nanoparticles (Au NPs) are promising materials for nanotechnology with applications in electronics, catalysis, and sensors. These applications depend on the ability to synthesize stable and monodisperse NPs. Herein, the design and synthesis of two series of dendritic thioether ligands and their ability to stabilize Au NPs is presented. The dendrimers have 1,3,5‐trisubstituted benzene branching units bridged by either meta‐xylene or ethylene moieties. A comparison between the two ligands shows how both size control and the stability of the NPs are influenced by the nature of the ligand–NP wrapping interaction. The meta‐xylene‐bridged ligands provided NPs with a narrow size distribution centered around a diameter of 1.2 nm, whereas the NPs formed with ethylene‐bridged dendrimers lack long‐term stability with NP aggregation detected by UV/Vis spectroscopy and transmission electron microscopy. The bulkier tert‐butyl‐functionalized meta‐xylene bridges form larger ligand shells that inhibit further growth of the NPs and thus provide a simple route to stable and monodisperse Au NPs that may find use as functional components in nanoelectronic devices.
Facilitating and Promoting Innovative Entrepreneurship in Hong Kong: Theory and Practice
Authors: Sharif Naubahar
Published: October 2011

This paper analyzes recent policy initiatives designed to stimulate innovative entrepreneurship in Hong Kong. I construct a conceptual framework informed by the theory of market failure and posit five key obstacles to innovative entrepreneurship in order to examine Hong Kong's efforts through public policy to strengthen innovative entrepreneurship and to offer broad policy prescriptions. Aligning the initiatives undertaken in Hong Kong with the barriers that inform the conceptual framework contributes to scholarship in the area of innovative entrepreneurship, lays the foundation for future research to match policy measures with outcomes in Hong Kong, and aids cross‐cultural research to determine whether aspects of the framing are specific or generalizeable. Copyright © 2011 ASAC. Published by John Wiley & Sons, Ltd.
The Clinical Characteristics, Laboratory Parameters, Electrocardiographic, and Echocardiographic Findings of Reverse or Inverted Takotsubo Cardiomyopathy: Comparison With Mid or Apical Variant
Authors: Song Bong Gun , Chun Woo Jung , Park Yong Hwan , Kang Gu Hyun , Oh JuHyeon , Lee Sang‐Chol , Park Seung Woo , Oh Jae K.
Published: October 2011

Background:

Although takotsubo cardiomyopathy (TTC) typically affects the apical and/or midventricular segments, several recent cases have reported a reverse or inverted variant of TTC. The aim of this study was to investigate the clinical characteristics, laboratory parameters, electrocardiographic, and echocardiographic findings in patients presenting as inverted TTC and compare those parameters to those presenting as mid or apical variant.

Hypothesis:

The clinical features of inverted TTC are different from those of other types of TTC.

Methods:

Of 103 patients enrolled from the TTC registry database, 20 showed inverted TTC (inverted TTC group), and 83 showed mid or apical variant (other TTC group).

Results:

Clinical presentations and in‐hospital courses were mostly similar between the groups. However, the inverted TTC group was younger (median, 54.5 vs 64.0 years; P = 0.006) than other TTC and had a higher prevalence of triggering stress (100% vs 77%, P = 0.018), whereas other TTC group had higher prevalence of dyspnea (58% vs 30%, P = 0.025), pulmonary edema (46% vs 20%, P = 0.035), cardiogenic shock (36% vs 10%, P = 0.023), T‐wave inversion (81% vs 60%, P = 0.049), and significant reversible mitral regurgitation (MR) (19% vs 0%, P = 0.033). Also, the inverted TTC group had significantly higher creatine kinase MB fraction (CK‐MB); CK‐MB (median, 30.7 vs 7.6 ng/mL; P = 0.001) and troponin‐I (median, 13.1 vs 1.6 ng/mL; P = 0.001), but lower N‐terminalpro‐brain natriuretic peptide (NT‐proBNP) levels (median, 613.3 vs 4987.0 pg/mL; P = 0.020).

Conclusions:

Inverted TTC presents at a younger age and has a higher prevalence of triggering stress, whereas other TTC has a higher prevalence of heart failure symptoms, significant reversible MR, and T‐wave inversion and higher NT‐proBNP levels despite other clinical features that are mostly similar. © 2011 Wiley Periodicals, Inc.

This study was supported by the Samsung Changwon Hospital Hyoseok Research Fund. The authors have no other funding, financial relationships, or conflicts of interest to disclose.
Interaction of low molecular weight hyaluronan with CD44 and toll‐like receptors promotes the actin filament‐associated protein 110‐actin binding and MyD88‐NFκB signaling leading to proinflammatory cytokine/chemokine production and breast tumor invasion
Authors: Bourguignon Lilly Y. W. , Wong Gabriel , Earle Christine A. , Xia Weiliang
Published: October 2011

Both high and low molecular weight hyaluronan (HMW‐HA vs. LMW‐HA) exist in various tissues and cells. In this study, we investigated LMW‐HA‐mediated CD44 interaction with Toll‐like receptors (TLRs), the actin filament‐associated protein (AFAP‐110), and a myeloid differentiation factor (MyD88) in breast tumor cells (MDA‐MB‐231 cells). Our data indicate that LMW‐HA (but not HMW‐HA) preferentially stimulates a physical association between CD44 and TLRs followed by a concomitant recruitment of AFAP‐110 and MyD88 into receptor‐containing complexes in breast tumor cells. LMW‐HA‐activated AFAP‐110 then binds to filamentous actin (F‐actin) resulting in MyD88/nuclear factor‐κB (NF‐κB) nuclear translocation, NF‐κB‐specific transcription, and target gene [interleukine 1β and interleukine‐8 (IL‐1β and IL‐8)] expression. These signaling events lead to proinflammatory cytokine/chemokine production in the breast tumor cells. AFAP‐110‐F‐actin (activated by LMW‐HA) also promotes tumor cell invasion. Downregulation of AFAP‐110 or MyD88 by transfecting breast tumor cells with AFAP‐110 siRNA or MyD88 siRNA, respectively not only blocks the ability of LMW‐HA to stimulate AFAP‐110‐actin function, but also impairs MyD88‐NF‐κB nuclear translocation and NF‐κB transcriptional activation. Consequently, both IL‐1β/IL‐8 production and tumor cell invasion are impaired. Taken together, these findings suggest that LMW‐HA plays an important role in CD44‐TLR‐associated AFAP‐110‐actin interaction and MyD88‐NF‐κB signaling required for tumor cell behaviors, which may contribute to the progression of breast cancer. © 2011 Wiley Periodicals, Inc.
Performance analysis for relay networks with hierarchical support vector machines
Authors: Liu Bao Yuan , Feng Vin Sen , Chang Shih Yu
Published: October 2011

In this paper, we consider a cooperative relay scheme for a mobile network with MIMO technology. The channel capacity for two well‐known relaying schemes are investigated: analogue relaying (amplify and forward) and digital relaying (decode and forward) from a mobile device to the base station through a relay node. In order to further increase the channel capacity, we propose an efficient hierarchical procedure based on support vector machine, namely hierarchical support vector machines (HSVM), to estimate the wireless networks condition approximately and design two ways (matched filter and minimum mean square error filter) of increasing the channel capacity according to the estimated wireless network condition. The proposed HSVM can estimate the wireless networks condition in much shorter time compared with the traditional minimum mean square error scheme without incurring much estimation error, which is spatial, useful for delay sensitive communication. For digital relaying, the effect of imperfect channel decode is also addressed. Our numerical results demonstrate the reduction of estimation complexity by adopting HSVM and the significant improvement of network capacity by applying the matched filter weight at relay nodes according to the network estimation. Copyright © 2011 John Wiley & Sons, Ltd.
NHERF1 regulates gp120‐induced internalization and signaling by CCR5, and HIV‐1 production
Authors: Kuang Yi‐Qun , Pang Wei , Zheng Yong‐Tang , Dupré Denis J.
Published: October 2011

The scaffolding protein Na+/H+exchanger regulator factor 1 (NHERF1) plays an important role in the trafficking of G protein‐coupled receptors. We previously demonstrated that NHERF1 is involved in chemokine receptor CCR5 homodimer internalization and signal transduction. Given the importance of CCR5 internalization during HIV‐1 infection, we evaluated NHERF1's contribution in HIV‐1 infection. We challenged human osteosarcoma cells coexpressing CD4 and CCR5 cells expressing either NHERF1 fragment domains or WT NHERF1 with an HIV‐1 strain to examine the effects of NHERF1 on HIV‐1 entry and replication. WT NHERF1 potentiates HIV‐1 envelope gp120‐induced CCR5 internalization, and promotes the replication of HIV‐1. In order to better understand how NHERF1 affects signal transduction, different domains of NHERF1 were overexpressed in cells to analyze their effect on the different signaling pathways. Here, we show that NHERF1 can associate with CCR5, and promote activation of the gp120‐induced MAPK/ERK, focal adhesion kinase and RhoA (Ras homolog gene family member A) signaling pathways. NHERF1 overexpression also increases HIV‐1 host cell migration triggered by gp120 via focal adhesion kinase (FAK) signaling. Finally, NHERF1 enhanced actin filament rearrangement in host cells, an important step in post‐entry HIV‐1 replication events. While postsynaptic density 95/disk‐large/zonula occludens 2 (PDZ2) appears to be the major contributor in those events, other domains also participate in the regulation of gp120‐induced signaling pathways. Altogether, our results suggest a very important role of the scaffold NHERF1 in the regulation of HIV‐1 entry and replication.