bluuebunny/crossref_metadata_2025 huggingface dataset:
Self‐Sharpening Teeth: Self‐Sharpening Mechanism of the Sea Urchin Tooth (Adv. Funct. Mater. 4/2011)
Authors: Killian Christopher E. , Metzler Rebecca A. , Gong Yutao , Churchill Tyler H. , Olson Ian C. , Trubetskoy Vasily , Christensen Matthew B. , Fournelle John H. , De Carlo Francesco , Cohen Sidney , Mahamid Julia , Scholl Andreas , Young Anthony , Doran Andrew , Wilt Fred H. , Coppersmith Susan N. , Gilbert Pupa U. P. A.
Published: February 2011

The sea urchin tooth is a mosaic of calcite crystals shaped precisely into plates and fibers, cemented together by a robust calcitic polycrystalline matrix. The tooth is formed continuously at one end, while it grinds and wears at the opposite end, the sharp tip. Remarkably, these teeth enable the sea urchin to scrape and bore holes into rock, yet the teeth remain sharp rather than dull with use. Here we describe the detailed structure of the tooth of the California purple sea urchin Strongylocentrotus purpuratus, and focus on the self‐sharpening mechanism. Using high‐resolution X‐ray photoelectron emission spectromicroscopy (X‐PEEM), scanning electron microscopy (SEM), EDX analysis, nanoindentation, and X‐ray micro‐tomography, we deduce that the sea urchin tooth self‐sharpens by fracturing at discontinuities in the material. These are organic layers surrounding plates and fibers that behave as the “fault lines” in the tooth structure, as shown by nanoindentation. Shedding of tooth components at these discontinuities exposes the robust central part of the tooth, aptly termed “the stone”, which becomes the grinding tip. The precise design and position of the plates and fibers determines the profile of the tooth tip, so as the tooth wears it maintains a tip that is continually renewed and remains sharp. This strategy may be used for the top‐down or bottom‐up fabrication of lamellar materials, to be used for mechanical functions at the nano‐ and micrometer scale.
Domino CN Coupling/Annulation versus CN Coupling/ Hydroamination of 2‐Alkynyl‐3‐bromobenzothiophenes and 2‐Alkynyl‐3‐bromothiophenes. Highly Efficient Synthesis of Benzothieno[3,2‐b]quinolines and Thieno[3,2‐b]pyrroles
Authors: Salman Ghazwan Ali , Hussain Munawar , Iaroshenko Viktor , Villinger Alexander , Langer Peter
Published: February 2011

While the palladium‐catalyzed reaction of 2‐alkynyl‐3‐bromothiophenes with anilines afforded thienopyrroles by a domino CN coupling/hydroamination process, the reaction of 2‐alkynyl‐3‐bromobenzothiophenes with anilines resulted, under identical conditions, in the formation of benzothienoquinolines by a domino CN coupling/annulation process. The electronic character of the aniline also has an influence on the product distribution.
Stable and Efficient Solid‐State Light‐Emitting Electrochemical Cells Based on a Series of Hydrophobic Iridium Complexes
Authors: Costa Rubén D. , Ortí Enrique , Tordera Daniel , Pertegás Antonio , Bolink Henk J. , Graber Stefan , Housecroft Catherine E. , Sachno Ludmila , Neuburger Markus , Constable Edwin C.
Published: February 2011

Light‐emitting electrochemical cells (LECs) based on ionic transition‐metal complexes (iTMCs) exhibiting high efficiency, short turn‐on time, and long stability have recently been presented. Furthermore, LECs emitting in the full range of the visible spectrum including white light have been reported. However, all these achievements were obtained individually, not simultaneously, using in each case a different iTMC. In this work, device stability is maintained by employing intrinsically stable ionic iridium complexes, while increasing the complex and the device quantum yields for exciton‐to‐photon conversion. This is done by sequentially modifying the archetype ionic iridium complex [Ir(ppy)2(bpy)][PF6], where Hppy is 2‐phenylpyridine and bpy is 2,2'‐bipyridine, with methyl and phenyl groups on the bpy ligand. A full photophysical and theoretical description of a series of four complexes, including the archetype as a reference, is presented and their performance in LECs is characterized. Upon selecting suitable substituents, a twofold increase is obtained in the photoluminescence quantum yield in a solid film. This is reflected in a significant increase in the efficiency over time curve for LECs using this complex.
Synthesis of cross‐linked polyethylene oxide‐acetal macrocycles for solid superbase catalysts
Authors: Trofimov Boris A. , Morozova Boris V. , Mikhaleva Al'bina I. , Tatarinova Inna V. , Markova Marina V. , Henkelmann Jochem
Published: February 2011

A novel long‐chain divinyl ether of tris(diethyleneglycol)‐bisacetal, has been synthesized by electrophilic addition of one molecule of diethylene glycol to two molecules of divinyl ether of diethylene glycol (DVDEG) in the presence of CF3COOH in quantitative yield. The monomer was cationically polymerized (BF3·OEt2, or complex LiBF4·MeO(CH2)2OMe) and copolymerized with DVDEG to deliver solid polymers the yields being 80–100%. The polymers represent the cross‐linked polyether‐polyacetal structures comprising macrocycles. The polymers were treated with 3% solution of KOH or CsOH in methanol to afford solid superbase complexes of KOH (CsOH) with cross‐linked polyether‐polyacetal macrocyclic networks. Preliminary tests have shown the complexes to be active catalysts for ethynylation of acetones and prototropic isomerization of methyl propargyl ethers to allenyl methyl ethers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Moisture‐induced effects on the tensile mechanical properties and glass‐transition temperature of poly(vinyl alcohol) films
Authors: Konidari M. V. , Papadokostaki K. G. , Sanopoulou M.
Published: February 2011

In this study, the effect of sorbed water on the tensile mechanical properties of noncrosslinked, thermally treated poly(vinyl alcohol) (PVA) films was studied. The Young's modulus, elongation at break, and tensile strength of the PVA films equilibrated at different relative humidities (0–86%) are reported, together with the depression of the glass transition of the polymer at each equilibrating humidity, as determined by temperature‐modulated differential scanning calorimetry. The results indicate that drastic changes in the tensile properties were correlated with the transition of the hydrated polymer from the glassy to the rubbery state. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of a nanoclay/triphenyl phosphate hybrid system on the fire retardancy of polycarbonate/acrylonitrile–butadiene–styrene blend
Authors: Feyz E. , Jahani Y. , Esfandeh M.
Published: February 2011

The effect of a hybrid system of nanoclay and triphenyl phosphate (TPP) on the fire retardancy of a polycarbonate (PC)/acrylonitrile–butadiene–styrene (ABS) blend was examined in this study. The nanoclay in the polymers decreased the peak heat release rates (PHRRs) with no significant effect on the ease of ignition and times to extinguishment. Improvements in the flame retardancy were observed only when nanoparticles were used with conventional flame‐retardant (FR) additives. Thermogravimetric analysis (TGA), cone calorimetry, and limited oxygen index (LOI)/UL 94 (Underwriters Laboratory) testing were used to investigate the thermal degradation, fire behavior, and flammability of the materials. The results show that when we used a combination of TPP and nanoclay as an FR system, degradation of the polymer blends was reduced as the TGA curves shifted to higher temperatures. PHRR in cone calorimetry testing decreased from 1032 kW/m2 for the PC/ABS blend to 300 kW/m2 for the PC/ABS/(12% TPP–2% nanoclay) sample, and the LOI increased from 23 to 35%, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis and characterization of glutaraldehyde‐crosslinked calcium alginate for fluoride removal from aqueous solutions
Authors: Vijaya Y. , Popuri Srinivasa R. , Reddy A. Subba , Krishnaiah A.
Published: February 2011

A novel biosorbent was developed by the crosslinking of an anionic biopolymer, calcium alginate, with glutaraldehyde. The glutaraldehyde‐crosslinked calcium alginate (GCA) was characterized by Fourier transform infrared spectroscopy and porosity and surface area analysis. The batch equilibrium and column flow adsorption characteristics of fluoride onto the biosorbent were studied. The effects of the pH, agitation time, concentration of adsorbate, and amount of adsorbent on the extent of adsorption were investigated. The experimental data were fitted to the Langmuir and Freundlich adsorption isotherms. The data were analyzed on the basis of the Lagergren pseudo‐first‐order, pseudo‐second‐order, and Weber–Morris intraparticle diffusion models. The maximum monolayer adsorption capacity of the GCA sorbent as obtained from the Langmuir adsorption isotherm was found to be 73.5 mg/g for fluoride. The χ2 and sum of squares of the error analysis were used to correlate the equilibrium isotherm models and kinetics. In addition, breakthrough curves were obtained from column flow experiments. The experimental results demonstrate that the GCA beads could be used for the defluoridation of drinking water through adsorption. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Nanocomposite super‐swelling hydrogels with nanorod bentonite
Authors: Darvishi Z. , Kabiri K. , Zohuriaan‐Mehr M. J. , Morsali A.
Published: February 2011

A modified bentonite (nanorod bentonite) was obtained from conventional bentonite by an ultrasonic treatment. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images indicated that modified bentonite comprised rod‐shape morphology without any change in the chemical structure confirmed by Fourier transform infrared (FTIR) spectroscopy and X‐ray diffraction (XRD) patterns. Novel super‐swelling hydrogels with nanocomposite structure were then prepared via solution polymerization of 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS) and (N‐[3‐(dimethylamino)propyl] methacrylamide) (DMAPMA) in the presence of the nanobentonite and a crosslinker. The DMAPMA consisted of either intercalant or monomer in the polymerization. The hydrogel products were characterized by FTIR, swelling studies, dynamic mechanical thermal analysis (DMTA), XRD, and rheological measurements. It was proposed that exfoliated and intercalated morphology were obtained at low and high‐nanobentonite contents, respectively. DMTA indicated that mechanical properties of the dried gel were improved with raising the clay content. In the water‐swollen state, storage modulus was considerably increased in nanocomposites having <8% of modified bentonite, and then it was decreased at the higher clay content due to interfering effect of the clay in polymerization progression. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Morphology, crystallization, and mechanical properties of poly(ethylene terephthalate)/multiwalled carbon nanotubes composites
Authors: Zhu Zhiguo , Wang Rui , Dong Zhenfeng , Huang Xiuqin , Zhang Dasheng
Published: February 2011

Poly(ethylene terephthalate)/multiwalled carbon nanotubes (PET/MWCNTs) with different MWCNTs loadings have been prepared by in situ polymerization of ethylene glycol (EG) containing dispersed MWCNTs and terephthalic acid (TPA). From scanning electronic microscopy images of nanocomposites, it can be clearly seen that the PET/MWCNTs composites with low‐MWCNTs contents (0.2 and 0.4 wt %) get better MWCNTs dispersion than analogous with high‐tube loadings (0.6 and 0.8 wt %). The nonisothermal crystallization kinetics was analyzed by differential scanning calorimetry using Mo kinetics equation, and the results showed that the incorporation of MWCNTs accelerates the crystallization process obviously. Mechanical testing shows that, in comparison with neat PET, the Young's modulus and the yield strength of the PET nanocomposites with incorporating 0.4 wt % MWCNTs are effectively improved by about 25% and 15%, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Retracted: Drug release properties of poly(vinyl pyrrolidone)/acrylic acid copolymer hydrogels
Authors: Alarifi Abdullah S.
Published: February 2011

The following article from the Journal of Applied Polymer Science, “Drug release properties of poly(vinyl pyrrolidone)/acrylic acid copolymer hydrogels,” by Abdullah S. Alarifi, published online on 14 February 2011 in Wiley Online Library (wileyonlinelibrary.com), and in Volume 120, pp. 3484‐3489, has been retracted by agreement between the journal's editors and Wiley Periodicals, Inc. The retraction has been agreed because of unacknowledged overlap with work previously published in the Arab Journal of Nuclear Sciences and Applications (2010, 43, 366), as well as in Proceeding, 2nd International Conference on Radiation Sciences and Applications (Egyptian Society of Radiation Sciences and Applications: Marsa Alam, Egypt, 2010; p 362).
Understanding the degradation of MEA in PEMFC: Definition of structural markers and comparison between laboratory and on‐site ageing
Authors: De Moor Gilles , Bas Corine , Lesage Freddy , Danérol Anne Sophie , Claude Eric , Rossinot Elisabeth , Paris Marion , Flandin Lionel , Albérola Nicole Dominique
Published: February 2011

Different accelerated tests in 12 fuel cells stack were performed in laboratory, namely on/off, back‐up, and base‐load regimes. In parallel, membrane electrode assemblies (MEA) were integrated in two “on‐site” systems for GSM relay application. One of them was dedicated to base‐load power applications while the second fuel cells coupled with photovoltaic panels operated in semibase load mode. To investigate the influence of the power profiles on MEA degradation, over 80 CCB MEAs (5 layers) were studied at different scales using ex situ characterizations such as tensile tests, TGA‐MS, DMTA, and SEM. A series of complementary microstructural ageing markers were thereby identified. The isolated influence of dry‐wet cycling on MEA properties was also established after passive hydro‐thermal (HT) ageing performed continuously for 10 months in the laboratory. The changes of each marker as a function of HT ageing time permitted to define a temporal benchmark. Based on these indicators, the main changes occurred in the MEA properties appear after a 5 months dry‐humid cycling (up to about 1800 cycles). The trends observed were useful to compare and estimate the degree of degradation of each ageing tests. Thus, the accelerated tests performed in laboratory for at least 500 h in stack did not reveal systematic MEA modifications. On the contrary, the 1500 h “on‐site” system operation results in some MEA degradations which origins are discussed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of pro‐oxidants on biodegradation of polyethylene (LDPE) by indigenous fungal isolate, Aspergillus oryzae
Authors: Konduri Mohan K. R. , Koteswarareddy G. , Rohini Kumar D. B. , Venkata Reddy B. , Lakshmi Narasu M.
Published: February 2011

Proxidant additives represent a promising solution to the problem of the environment contamination with polyethylene film litter. Pro‐oxidants accelerate photo‐ and thermo‐oxidation and consequent polymer chain cleavage rendering the product apparently more susceptible to biodegradation. In the present study, fungal strain, Aspergillus oryzae isolated from HDPE film (buried in soil for 3 months) utilized abiotically treated polyethylene (LDPE) as a sole carbon source and degraded it. Treatment with pro‐oxidant, manganese stearate followed by UV irradiation and incubation with A. oryzae resulted in maximum decrease in percentage of elongation and tensile strength by 62 and 51%, respectively, compared with other pro‐oxidant treated LDPE films which showed 45% (titanium stearate), 40% (iron stearate), and 39% (cobalt stearate) decrease in tensile strength. Fourier transform infrared (FTIR) analysis of proxidant treated LDPE films revealed generation of more number of carbonyl and carboxylic groups (1630–1840 cm−1 and 1220–1340 cm−1) compared with UV treated film. When these films were incubated with A. oryzae for 3 months complete degradation of carbonyl and carboxylic groups was achieved. Scanning electron microscopy of untreated and treated LDPE films also revealed that polymer has undergone degradation after abiotic and biotic treatments. This concludes proxidant treatment before UV irradiation accelerated photo‐oxidation of LDPE, caused functional groups to be generated in the polyethylene film and this resulted in biodegradation due to the consumption of carbonyl and carboxylic groups by A. oryzae which was evident by reduction in carbonyl peaks. Among the pro‐oxidants, manganese stearate treatment caused maximum degradation of polyethylene. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Solution casting, characterization, and performance evaluation of perfluorosulfonic sodium type membranes for chlor‐alkali application
Authors: Mohammadi Fereidoon , Rabiee Ahmad
Published: February 2011

This investigation describes solution casting, characterization and performance evaluation of perfluorosulfonic sodium (PFSS) type membranes prepared by three different methods from Nafion solution and Nafion‐117 for Chlor‐Alkali (CA) application. A Chlor‐Alkali experimental set‐up was designed and constructed for performance evaluation of the recast membranes. The chemical structure of solution cast films was studied and confirmed by FTIR (Fourier Transform infrared spectroscopy) and ATR (Attenuated total reflection) techniques. The physical properties of solution cast films including mechanical strength, thermal behavior, water sorption, ion‐exchange capacity (IEC), morphology, and crystallinity were also evaluated. All the recast polymeric films behave like elastomers with low modulus but high elongation at break. Differential scanning calorimetric (DSC) thermograms of solution cast films showed two endothermic peaks at 180°C and 250°C attributed to matrix glass transition (Tgm) and ionic cluster glass transition (Tgc) of the Nafion polymer, respectively. The water uptake of polymeric films was reasonable in comparison with Nafion‐117. Solution casting has no significant effect on ion exchange capacity of the recast films. The scanning electron microscope (SEM) micrograph showed that the morphology of recast films is reasonably similar with Nafion‐117. However, the as‐cast films have some micro pores, which are produced during solution casting. The crystallinity of annealed film, because of the heat treatment was slightly high due to local ordering. According to the experimental results, which obtained from performance evaluation in CA cell, the properties of recycled films are similar to commercial membranes such as Nafion‐117 and can be used in CA process. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis and characterization of alkali‐soluble photosensitive polysiloxane urethane acrylate
Authors: Sun Fang , Liao Bo , Zhang Lu , Du Hong‐Guang , Huang Yue‐Dong
Published: February 2011

A novel alkali‐soluble photosensitive polysiloxane urethane acrylate (APSUA) was synthesized via reacting bifunctional isocyanate with three kinds of hydroxyl group respectively, from hydroxyl silicone oil, dimethylol propionic acid (DMPA), and a compound which also has acrylate groups. The compound was prepared via reacting acrylic acid with N,N,N′,N′‐tetraglycidyl ‐4,4′‐diamino diphenyl methane (AG‐80). The optimum temperature for the synthesis reaction of APSUA was found to be 50°C. The structure of the oligomer was characterized by IR, 1HNMR, and GPC. The number‐average molecular weight of the APSUA was 7795. The APSUA possesses excellent compatibility with most of acrylate monomers. The effect of concentration of photoinitiator and monomers on the photopolymerization kinetics of the oligomer APSUA was investigated by real‐time infrared spectroscopy (RT‐IR). The results show that APSUA can well photopolymerize under UV‐irradiation. The optimal concentration of photoinitiator (Darocur 1173) was determined as 0.1 wt %. The system of APSUA with DPGDA monomer has higher polymerization rate (0.0521 s−1) and higher double bond conversion (93.2%), respectively. The APSUA system with acrylate monomers can form regular image under UV‐irradiation through a patterned mask. The cured coating film of the APSUA system possesses excellent flexibility, toughness and heat resistance. The APSUA system can dissolve in 1% sodium carbonate solution easily and completely. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Application of different methods for the thermogravimetric analysis of polyethylene samples
Authors: Baloch Musa Kaleem , Khurram Malik Jehan Zeb , Durrani Gulrez Fatima
Published: February 2011

The kinetics of thermal degradation of standard and commercial polyethylene (PE) samples is investigated, by employing different methods like Flynn‐Wall‐Ozawa, Coats‐Redfern, Kissinger, and Augis‐Bennett. The order of reaction obtained was 0.741 and 1.124 for standard and commercial samples, respectively. The activation energy obtained in this way was 279.6–311.0 kJ/mol and 300.5–374.1 kJ/mol for standard and commercial samples, respectively, depending upon the method used. The activation energy obtained by different methods decreases in the order Flynn‐Wall‐Ozawa» Augis and Bennett» Kissinger» Coats and Redfern. It is observed that most of the methods deviated from the experimental results, in low (0.1–0.3) degree of conversion region but worked well in the middle (0.5–0.7) degree of conversion region. It has also been noticed that both the order and activation energy were slightly dependent over the heating rate and degree of conversion. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Extraction and characterization of lignins from maize stem and sugarcane bagasse
Authors: Sun Xiao‐Feng , Wang Haihong , Zhang Guangcheng , Fowler Paul , Rajaratnam Mohanathas
Published: February 2011

Lignins were isolated from maize stem and sugarcane bagasse by using mild dioxane or acidic dioxane solution. The result of nitrobenzene oxidation of the isolated lignins shows that there is a high proportion of p‐hydroxyphenyl alcohol in the lignins of maize stem and sugarcane bagasse. The lignins isolated from maize stem and sugarcane bagasse have relatively same value of the weight‐average (Mw = 3405–3868 g mol−1) and number‐average (Mn = 1411–1612 g mol−1) molecular weights, and polydispersity (Mw/Mn = 2.24–2.51). Acidic dioxane treatment did attack the β‐aryl ether structures in lignins, in particular for β‐aryl syringyl ethers, and broke the ester bonds between arabinose and ferulic acid that etherified to lignins, and it also cleaved lots of bonds in hemicellulosic polymer. The proportion of β‐O‐4 (threo) guaiacyl units is higher than that of β‐O‐4 (erthreo) guaiacyl units. The phenyl glycoside and benzyl ether linkages between lignin and hemicelluloses are also demonstrated in NMR analysis. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Optimizing color fading effect of cotton denim fabric by enzyme treatment
Authors: Kan C. W. , Yuen C. W. M. , Wong W. Y.
Published: February 2011

In this article, the effect of enzyme treatment using neutral cellulase on the color fading property of cotton denim fabric was studied. Four enzyme processing parameters namely treatment temperature, treatment time, pH value, and agitation were considered. To investigate the optimum condition for the enzyme treatment, an orthogonal analysis was used and, based on the K/S summation value (K/S Sum), the optimum condition for enzyme treatment in this study was treatment temperature = 50°C; treatment time = 30 min; pH value = 8; and agitation = 50 steel balls (simulated mild agitation) for the best color fading achievement with desired worn and aged effect. Meanwhile, the level of importance based on the orthogonal analysis was in the order: treatment temperature > treatment time > agitation > pH and the effect of each processing factors was also discussed. In addition, other properties like CIE Lab values, weight loss, and color fastness to laundering and crocking were also evaluated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Silica‐modified SBR/BR blends
Authors: Wu Weili , Chen Dajun
Published: February 2011

The purpose of this article is that the silica‐modified SBR/BR blend replaces natural rubber (NR) in some application fields. The styrene‐butadiene rubber (SBR) and cis‐butadiene rubber (BR) blend was modified, in which silica filler was treated with the r‐Aminopropyltriethoxysilane (KH‐550) as a coupling agent, to improve mechanical and thermal properties, and compatibilities. The optimum formula and cure condition were determined by testing the properties of SBR/BR blend. The properties of NR and the silica‐modified SBR/BR blend were compared. The results show that the optimum formulawas 80/20 SBR/BR, 2.5 phr dicumyl peroxide (DCP), 45 phr silica and 2.5 mL KH‐550. The best cure condition was at 150°C for 25 min under 10 MPa. The mechanical and thermal properties of SBR/BR blend were obviously modified, in which the silica filler treated with KH‐550. The compatibility of SBR/BR blend with DCP was better than those with benzoyl peroxide (BPO) and DCP/BPO. The crosslinking bonds between modified silica and rubbers were proved by Fourier transform infrared analysis, and the compatibility of SBR and BR was proved by polarized light microscopy (PLM) analysis. The silica‐modified SBR/BR blend can substitute for NR in the specific application fields. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
Ultrasonic degradation of polyvinyl pyrrolidone in mixed water/acetone
Authors: Mehrdad Abbas
Published: February 2011

The ultrasonic degradation of polyvinyl pyrrolidone solutions was carried out in mixtures water and acetone at 25°C to investigate the effect of solvent composition and solution concentration on the rate of degradation. The obtained limiting molecular weights indicate that the extent of degradation was decreased by increasing acetone volume fraction and solution concentration. The obtained limiting molecular weights were correlated in terms of concentration and acetone volume fraction. The calculated rate constants indicate that the rate of degradation was decreased by increasing acetone volume fraction and solution concentration. The calculated rate constants were correlated in terms of concentration, acetone volume fraction and molecular weight of polymer. This degradation behavior was interpreted in terms of vapor pressure of mixtures water and acetone, viscosity and concentration of polymer solutions. Vapor pressure of mixtures water and acetone were increased by increasing acetone volume fraction, and so the vapor easily entered the cavitation bubbles during their growth. This caused a reduction in collapsing shock because of a cushioning effect; therefore, the rate of degradation decreased. As the solution concentration increased, the viscosity increased and caused a reduction in the cavitation efficiency, and so the rate of degradation is decreased. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Influence of corona treatment on adhesion and mechanical properties in metal/polymer/metal systems
Authors: Carradò A. , Sokolova O. , Donnio B. , Palkowski H.
Published: February 2011

The effect of corona treatment (CT) on the adhesion at the metal–polymer interface was studied. Metal/polymer/metal laminates were manufactured by the laboratory roll‐bonding process with preliminary corona surface treatment of the polymer core: a polyethylene and polypropylene sheet as well as steel sheet. It was treated with corona discharge to increase its surface energy and the adhesion to metal, an austenitic steel. The adhesion, which was measured by T‐peel and shear tests, was increased by 43% of crack peel and 22% of mean peel resistance respectively, after 120 s CT. On the basis of scanning electron spectroscopy observations, improvements in the adhesive properties were attributed to the change in the interfacial morphology. In mechanical tests, yield and tensile strengths were strongly influenced by CT, indicating that these laminates were sensitive to interfacial phenomena. However, elongation at rupture of the composites was found to be unchanged. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
Effect of hydrogen bonding on characterization of polyamide 612 and ethylene vinyl alcohol copolymer blends
Authors: Cui Li , Wang Zhi‐Chao , Zhu Ping , Yeh Jen‐Taut
Published: February 2011

Hydrogen bonding interaction in the blends of polyamide 612 (PA612)/ethylene vinyl alcohol copolymer (EVOH) and the effect of the hydrogen bonds on the characterization of PA612/EVOH were investigated. Fourier transform infrared spectra (FTIR) analysis indicated that the interactions between the carbonyl groups of PA612 and hydroxyl groups of EVOH increase as the content of EVOH in PA612/EVOH specimens increase. This interaction between PA612 and EVOH leads to their miscibility to some extent in the amorphous region and even some effects on their crystal phase, respectively. Further isothermal crystallization behavior of PA612/EVOH indicates that the hydrogen bonding between PA612 and EVOH leading difficulty in crystallization of PA612. Several kinetics equations are employed to describe the effects of EVOH on the crystallization properties of PA612 in PA612/EVOH blends in detail. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Pharmacological Evaluation of Halogenated and Non‐halogenated Arylpiperazin‐1‐yl‐ethyl‐benzimidazoles as D2 and 5‐HT2A Receptor Ligands
Authors: Tomić Mirko , Vasković Djurdjica , Tovilović Gordana , Andrić Deana , Penjišević Jelena , Kostić‐Rajačić Sladjana
Published: February 2011

Five groups of previously synthesized and initially screened non‐substituted and 4‐halogenated arylpiperazin‐1‐yl‐ethyl‐benzimidazoles were estimated for their in‐vitro binding affinities at the rat D2, 5‐HT2A, and α1‐adrenergic receptors. Among all these compounds, 2‐methoxyphenyl and 2‐chlorophenyl piperazines demonstrate the highest affinities for the tested receptors. The effects of 4‐halogenation of benzimidazoles reveal that substitution with bromine may greatly increase the affinity of the compounds for the studied receptors, while the effect of substitution with chlorine is less remarkable. Most of the tested components show 5‐HT2A/D2 pKi binding ratios slightly above or less than 1, while only 4‐chloro‐6‐(2‐{4‐[3‐(trifluoromethyl)phenyl]piperazin‐1‐yl}ethyl)‐1H‐benzimidazole expresses an appropriate higher binding ratio (1.14), which was indicated for atypical neuroleptics. This compound exhibits a non‐cataleptic action in rats and prevents d‐amphetamine‐induced hyperlocomotion in mice, which suggest its atypical antipsychotic potency.
The Design and Cytotoxic Evaluation of Some 1‐Aryl‐3‐isopropylamino‐1‐propanone Hydrochlorides towards Human Huh‐7 Hepatoma Cells
Authors: Mete Ebru , Gul H. Inci , Cetin‐Atalay Rengul , Das Umashankar , Sahin Ertan , Gul Mustafa , Kazaz Cavit , Dimmock Jonathan R.
Published: February 2011

A series of 1‐aryl‐3‐isopropylamino‐1‐propanone hydrochlorides 1 and a related heterocyclic analog 2 as candidate antineoplastic agents were prepared and the rationale for designing these compounds is presented. A specific objective in this study is the discovery of novel compounds possessing growth‐inhibiting properties of hepatoma cells. The compounds in series 1 and 2 were prepared and their structures established unequivocally. X‐ray crystallography of two representative compounds 1d and 1g were achieved. Over half of the compounds are more potent than 5‐fluorouracil which is an established drug used in treating liver cancers. QSAR evaluations and molecular modeling studies were undertaken with a view to detecting some physicochemical parameters which govern cytotoxic potencies. A number of guidelines for amplification of the project have been formulated.
Essential role of microRNA‐155 in the pathogenesis of autoimmune arthritis in mice
Authors: Blüml Stephan , Bonelli Michael , Niederreiter Birgit , Puchner Antonia , Mayr Georg , Hayer Silvia , Koenders Marije I. , van den Berg Wim B. , Smolen Josef , Redlich Kurt
Published: February 2011

Objective

MicroRNAs (miRNA) are a new class of regulatory elements. Altered expression of miRNA has been demonstrated in the inflamed joints of patients with rheumatoid arthritis (RA). The aim of this study was to examine the role of miRNA in the pathogenesis of autoimmune arthritis, using 2 murine models.

Methods

Collagen‐induced arthritis (CIA) and K/BxN serum‐transfer arthritis were induced in wild‐type (WT) and miR‐155–deficient (miR‐155−/−) mice. The severity of arthritis was determined clinically and histologically. Anticollagen antibodies and cytokines were measured by enzyme‐linked immunosorbent assay. The cellular composition of the draining lymph nodes after induction of CIA was measured by flow cytometry.

Results

The miR‐155−/− mice did not develop CIA. Deficiency in miR‐155 prevented the generation of pathogenic autoreactive B and T cells, since anticollagen antibodies and the expression levels of antigen‐specific T cells were strongly reduced in miR‐155−/− mice. Moreover, Th17 polarization of miR‐155−/− mouse T cells was impaired, as shown by a significant decrease in the levels of interleukin‐17 (IL‐17) and IL‐22. In the K/BxN serum‐transfer arthritis model, which only depends on innate effector mechanisms, miR‐155−/− mice showed significantly reduced local bone destruction, attributed to reduced generation of osteoclasts, although the severity of joint inflammation was similar to that in WT mice.

Conclusion

These results demonstrate that miR‐155 is essentially involved in the adaptive and innate immune reactions leading to autoimmune arthritis, and therefore miR‐155 might provide a novel target for the treatment of patients with RA.
A detailed comparative study of high‐resolution ultrasound and micro–computed tomography for detection of arthritic bone erosions
Authors: Finzel Stephanie , Ohrndorf Sarah , Englbrecht Matthias , Stach Christian , Messerschmidt Janin , Schett Georg , Backhaus Marina
Published: February 2011

Objective

To test whether bony lesions appearing on ultrasound (US) imaging are cortical breaks detectable by micro–computed tomography (micro‐CT).

Methods

Twenty‐six subjects (14 with rheumatoid arthritis, 6 with psoriatic arthritis, and 6 healthy controls) were assessed for bone erosions at the radial, palmar, and dorsal regions of the second metacarpophalangeal (MCP) joint and the palmar and dorsal regions of the third and fourth MCP joints. All patients underwent US and, for validation of the results, micro‐CT scanning. The prevalence and severity of bone erosions as determined by US and by micro‐CT were recorded and compared.

Results

Overall there was a good correlation between the severity of erosions as assessed by US and by micro‐CT (r = 0.463, P < 0.0001). False‐negative results (US negative/micro‐CT positive) were obtained in only 9.9% of the joint regions and were mostly due to small erosive lesions at the dorsal sides of the MCP joints. False‐positive results (US positive/micro‐CT negative) were more frequent (28.6%) and were primarily based on vascular bone channels at the palmar sides of the MCP joints as well pseudo‐erosions created by osteophytes.

Conclusion

These data show that the majority of bone lesions appearing on US are indeed bone erosions with a cortical break. The sensitivity of US for detecting bone erosions was high and there was a good correlation between the severity of bone erosions as assessed by US and as assessed by micro‐CT. Specificity of US for bone erosions was substantially lower, suggesting that smaller lesions seen on US do not always represent breaks in the cortical bone surface.
Concurrent climate impacts of tropical South America land‐cover change
Authors: Hirota Marina , Oyama Marcos Daisuke , Nobre Carlos
Published: February 2011

The climatic effects of concurrent land‐cover changes in Amazonia and Northeast Brazil (NEB) were evaluated by simulations using the Center for Weather Forecasting and Climate Studies Atmospheric General Circulation Model (CPTEC‐AGCM). Three experiments were performed: Amazon savannization, NEB desertification and both land‐cover changes occurring concurrently. We found that land‐cover change from adjacent areas do affect both Amazon and NEB regions and that the negative precipitation anomaly in NEB due to concurrent land‐cover changes in Amazon and NEB is weaker than the linear addition of the anomalies considering the land‐cover changes separately (synergistic behaviour). A simple mechanism was proposed to explain this behaviour. Copyright © 2011 Royal Meteorological Society
Sensitivity of the mid‐winter Arctic stratosphere to QBO width in a simplified chemistry–climate model
Authors: Hurwitz M. M. , Braesicke P. , Pyle J. A.
Published: February 2011

This study is the first to assess the sensitivity of the mid‐winter Arctic stratosphere to variability in the width of the quasi‐biennial oscillation (QBO). Differences between a pair of idealised simulations with a simplified chemistry–climate model are examined. The width of the QBO appears to have equal influence on the Arctic stratosphere as does the phase (i.e. the Holton‐Tan mechanism). In the model, a wider QBO acts like a preferential shift towards the easterly phase of the QBO. That is, on average, a wider QBO is associated with a weaker Arctic vortex and with enhanced total ozone at high latitudes. Copyright © 2011 Royal Meteorological Society
New measures of the orientation of the linear structure in the sunward hemisphere of the coma of Comet 19P/Borrelly: apparitions of 1994, 2001, and 2008
Authors: Pansecchi L.
Published: February 2011

The sky‐projected orientation (position angle) of the axis (line of maximum density or maximum brightness) of the long time‐known, linear structure (LS) in the sunward hemisphere of the coma of Comet 19P/Borrelly is measured on 45 photographs taken by different observers under different projection conditions and covering three consecutive apparitions (1994, 2001, and 2008) for a total time interval of 5174 days. The analysis of the results by a tomographic approach yields an LS axis constantly oriented towards a fixed point in the space, at Right Ascension 214°.4 ± 0°.5 and Declination –7°.0 ± 0°.5 (J2000), corresponding to an obliquity of 103°.5 ± 1° and an orbital longitude of 147°.2 ± 1°, throughout the relevant interval. Such coordinates are close to the ones found by other authors for the spatial orientation of the nucleus spin axis during the apparitions of 1994 and 2001. In the hypothesis of an LS orientation aligned with the nucleus spin axis, the new results confirm the previous ones and show that this orientation remained unchanged during the subsequent 2008 apparition (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The shapes of light curves of Mira‐type variables
Authors: Lebzelter T.
Published: February 2011

Using a sample of 454 Mira light curves from the ASAS survey we study the shape of the light variations in this kind of variable stars. Opposite to earlier studies, we choose a general approach to identify any deviation from a sinusoidal light change. We find that about 30% of the studied light curves show a significant deviation from the sinusoidal reference shape. Among these stars two characteristic light curve shapes of comparable frequency could be identified. Some hint for a connection between atmospheric chemistry and light curve shape was found, but beside that no or only very weak relations between light curve shape and other stellar parameters seem to exist (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hα observations with DEFPOS
Authors: Sahan M.
Published: February 2011

A 7.5 cm, dual étalon Fabry‐Pérot spectrometer called DEFPOS has been set up at Coudé focus of 150 cm RTT150 telescope at TUBITAK National Observatory (TUG, Antalya, Turkey) to investigate the physical properties of Diffuse Ionized Gas (DIG) in our Galaxy. The spectrometer, having a 4 arcmin circular field of view over a 200 km s–1 (4.4 Å) spectral window near Hα, has been used to observe H II regions and Planetary Nebulae (PNe) since May 2007 (Sahan et al. 2009). Early observations have been analyzed and physical and kinematic properties such as the intensity, the line width, and the LSR velocity are presented here. These values are compared with earlier results from different studies. In this study, I discuss some results obtained by DEFPOS, including two H II regions (Sh2‐156, Sh2‐157), and two PNe (NGC 1360, and NGC 6826). The Intensities, the radial velocities and the line widths of the Hα emission line vary from 101.4R to 149.97R (1 Rayleigh =106/4π photons cm–2 sr–1 s–1 = 2.41 × 10–7 erg cm–2 s–1 sr–1 at Hα), –41.19 km s–1 to +8.34 km s–1, and 39.55 km s–1 to 58.23 km s–1, respectively (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the CH B‐X (1, 0) band in translucent clouds
Authors: T.  , Weselak  , Galazutdinov G. , Beletsky Y. , Krełowski J.
Published: February 2011

We present observations of CH B‐X (1, 0) band toward 13 translucent sightlines. The given precise positions (at 3627.403, 3633.289, 3636.222 Å) are derived by means of shifting our spectra to the rest velocity frame using B‐X (0, 0) features (at 3878, 3886 and 3890 Å). The proposed oscillator strengths (equal to 0.00035, 0.00104, 0.00069, respectively) are based on f ‐values of the CH B‐X (0, 0) system, i.e. 0.00110, 0.00320, 0.00210 (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A web‐tool for population synthesis of near‐by cooling neutron stars: An on‐line test for cooling curves
Authors: Boldin P.A. , Popov S.B. , Tetzlaff N.
Published: February 2011

We present a new web‐tool – Net‐PSICoNS – for population synthesis of isolated near‐by cooling neutron stars (NSs). The main aim is to provide an easy test of models of the NS thermal evolution which can be used by groups studying this subject. A user can upload cooling curves for a set of masses, modify the mass spectrum if necessary, change radii to fit the EoS used for cooling curve calculations, and then a population synthesis of close‐by isolated cooling NSs is performed. The output includes the log N ‐log S distribution confronted with the ROSAT observations and several other sets of data. In this paper, we summarize the idea of the test proposed by Popov et al. (2006), and present a user's manual for the web‐tool (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Identifying star clusters in a field: A comparison of different algorithms
Authors: Schmeja S.
Published: February 2011

Star clusters are often hard to find, as they may lie in a dense field of background objects or, because in the case of embedded clusters, they are surrounded by a more dispersed population of young stars. This paper discusses four algorithms that have been developed to identify clusters as stellar density enhancements in a field, namely stellar density maps from star counts, the nearest neighbour method and the Voronoi tessellation, and the separation of minimum spanning trees. These methods are tested and compared to each other by applying them to artificial clusters of different sizes and morphologies. While distinct centrally concentrated clusters are detected by all methods, clusters with low overdensity or highly hierarchical structure are only reliably detected by methods with inherent smoothing (star counts and nearest neighbour method). Furthermore, the algorithms differ strongly in computation time and additional parameters they provide. Therefore, the method to choose primarily depends on the size and character of the investigated area and the purpose of the study (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparisons of u ‐, g ‐, r ‐, i ‐, and z ‐band luminosity distributions between galaxy members of compact groups and isolated galaxies
Authors: Deng X.‐F. , Zou S.‐Y.
Published: February 2011

To investigate the environmental dependence of u ‐, g ‐, r ‐, i ‐, and z ‐band luminosities, we perform comparative studies of luminosity distributions between galaxy members of compact groups (CGs) and isolated galaxies. It is found that for the r, i, and z bands isolated galaxies have a higher proportion of faint galaxies and a lower proportion of luminous galaxies than galaxy members of CGs, but for the u band an opposite trend is observed. The correlation between the g ‐band luminosity and the environment has different trends in different luminosity regions (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical multiband surface photometry of a sample of Seyfert galaxies: III. Global, isophotal, and bar parameters
Authors: Slavcheva‐Mihova L. , Mihov B.
Published: February 2011

This paper is third in a series, studying the optical properties of a sample of Seyfert galaxies. Here we present a homoge neous set of global (ellipticity, position angle, inclination, and total magnitude) and isophotal (semi‐major axis and colour indices at 24V mag arcsec–2) parameters of the galaxy sample. We find the following median corrected isophotal colour indices: (B – IC)(0)24 = 1.9 mag arcsec–2 and (V – IC)(0)24 = 1.1 mag arcsec–2. A set of bar parameters (ellipticity, position angle, semi‐major axis corresponding to the ellipticity maximum in the bar region, and length) are also reported; deprojection has been applied to the bar ellipticity, length, and relative length in terms of galaxy isophotal semi‐major axis. Regarding bar length estimation, we use a method, based on the relation between the behaviour of the profiles and orbit analysis. The so estimated bar length tightly correlates with the semi‐major axis, corresponding to the ellipticity maximum with a median ratio of the former to the latter of 1.22. The median of the deprojected bar ellipticity, length, and relative length are 0.39, 5.44 kpc, and 0.44, respectively. There is a correlation between the deprojected bar length and the corrected isophotal semi‐major axis at 24V mag arcsec–2. Three of the 17 large‐scale bars appear strong, based on the deprojected bar ellipticity as a first‐order approximation of bar strength. The deprojected relative bar length does not appear to correlate with the bar ellipticity (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Strömgren Hβ ‐photometry of stars in dark clouds
Authors: Piehl D. , Briley M. , Kaltcheva N.
Published: February 2011

We present uvbyβ photometry of 64 stars in 6 small dark clouds. From the photometry we infer approximate spectral types of the observed stars and derive distances and color excesses for each of them. We further derive new distance estimates to some of the globules based on the distances of individual stars possibly included in their peripheries. For clouds where sufficient target stars are available (CB3, CB52, and CB54), a clear trend of increasing linear polarization (as measured by Sen et al. 2000) with extinction is observed. We also find excellent correlation between polarization and extinction for the entire sample. The location of the stars on the polarization‐extinction diagram is consistent with that for field stars found by Serkowski et al. (1975). The relation between polarization and extinction evident for the stars of our sample suggests perfect grain alignment and constant grain properties along each line of sight (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Meckel's diverticulum: A review
Authors: Uppal Kiranjit , Shane Tubbs R. , Matusz Petru , Shaffer Kitt , Loukas Marios
Published: February 2011

Meckel's diverticulum is the most prevalent congenital abnormality of the gastrointestinal tract. This anomaly is due to the incomplete obliteration ofthe omphalomesenteric duct during the 7th week of gestation and is classically located 2 feet proximal to the ileocecal valve. Variations of this congenital malformation have been recorded based on location, size, and form. While most of the population may be asymptomatic, clinical manifestation, including gastrointestinal bleed and intestinal obstruction, can emerge. Despite the frequency of Meckel's diverticulum, it is commonly misdiagnosed due to its mimicry of appendicitis. This article aimed to review this derailment of embryological development. Clin. Anat. 24:416–422, 2011. © 2011 Wiley‐Liss, Inc