bluuebunny/crossref_metadata_2025 huggingface dataset:
Layer‐by‐layer structured gelatin nanofiber membranes with photoinduced antibacterial functions
Authors: Lu Ang , Ma Zhaocheng , Zhuo Jingyuan , Sun Gang , Zhang Guodong
Published: June 2012

Gelatin (GE) nanofiber suspensions prepared by the extrusion of an immiscible polymer solution blend were cast into nanofibrous membranes. An organic chemical capable of generating radicals under photoexposure, anthraquinone‐2,6‐disulfonic acid (AQS), was assembled layer by layer (LBL) onto the gelatin nanofiber membranes. The composite gelatin nanofibrous membranes assembled with AQS demonstrated excellent photoinduced antibacterial properties by killing bacteria. Scanning electron microscopy images demonstrated that the composite nanofibrous membranes maintained a well‐defined nanofiber morphology and large specific surface area after LBL assembly. Moreover, the nanofiber morphology and nanofibrous structure of the composite nanofibrous membranes were completely reserved after photoexposure. An analysis of the cell indicated that the composite gelatin nanofibrous membranes assembled with AQS exhibited the same biocompatibility as the original gelatin nanofibers. These results demonstrate that AQS LBL‐assembled gelatin nanofibrous membranes could be a potential candidate for wound dressing applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
The effect of microwave irradiation on poly(vinyl alcohol) dissolved in ethylene glycol
Authors: Bernal Andres , Kuritka Ivo , Kasparkova Vera , Saha Petr
Published: June 2012

Poly(vinyl alcohol) (PVA) dissolved in ethylene glycol is subjected to microwave (MW) irradiation for 1 h to determine possible degradation. Fourier transform infrared spectroscopy results show that MW treatment produces a minor effect on the solutions. Ultraviolet–visible spectroscopy suggests that PVA could undergoes loss of hydroxyl groups followed by formation of unsaturated conjugated bonds although the extent of degradation is limited, whereas size exclusion chromatography indicates that MW irradiation do not cause significant changes in PVA molar mass and neither chain cleavage nor crosslinking reactions are observed. Hence, polymer degradation induced by MWs in solution can be considered as negligible for prospective applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Polyaniline, ethylene vinyl acetate semi‐conductive composites as pressure sensitive sensor
Authors: Rahaman M. , Chaki T. K. , Khastgir D.
Published: June 2012

This study focuses on the pressure sensitivity of ethylene vinyl acetate (EVA)/polyaniline (Pani) composites prepared through in situ polymerization of aniline in solutions of insulating EVA matrix. It is found that both DC and AC resistivity of the composites decreases with the increase in Pani concentration. The investigation shows that the composites senses to applied pressure through the decrease in resistivity with the increase in applied pressure. Moreover, the pressure sensitivity is also effective when the composites are kept under constant load for a period of time. Both DC and AC resistivity are found to decrease exponentially with respect to time. Relaxation time for the composites has been calculated and found that more time is required to be relaxed for the composite with lower Pani content. However, the composite with lower Pani content exhibits relatively higher change in electrical properties when subjected to both the applied pressure and time. The results show that these composites can be used as pressure sensitive sensor. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Effect of gamma‐irradiation on the electret properties of poly(L‐lactide)
Authors: Yovcheva Temenuzhka , Marudova Mariya , Viraneva Asya , Gencheva Elena , Balabanov Nikola , Mekishev Georgi
Published: June 2012

Electret stability of poly(L‐lactide) (PLA) films, gamma‐irradiated up to 100 kGy has been investigated by measuring the surface potential during the storage period. PLA samples—40‐μm thick films—were prepared by the casting method and then irradiated in a60Co radiation facility at a dose rate of 0.25 kGy/h. The structural changes during the irradiation were estimated by viscometric, differential scanning calorimetry and scanning electron microscope measurements. Random chain scission and appearance of end radicals are the most probable results of the irradiation process. After irradiation, the samples were charged in a corona discharge system and surface potential was measured by the method of the vibrating electrode with compensation. The values of the surface potential of the irradiated samples were higher in comparison with the non‐irradiated samples. This effect could be related to the degradation of the macromolecules and changes in the crystal state of PLA during the irradiation. Both of the mentioned factors lead to structural defects that increase the number of discrete trapping levels. The effect of low pressure on the surface potential drop was also investigated. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Chiral separation with polyurea membrane consisting ofL‐lysinyl residue: Proposal of facile method for prediction of permselectivity
Authors: Hatanaka Makoto , Nishioka Yuki , Yoshikawa Masakazu
Published: June 2012

Novel chiral polyureas were prepared fromL‐lysine‐4‐nitroanilide and 2,4‐toluene diisocyanate. The polyurea thus prepared gave a durable self‐standing membrane that can be directly converted into molecular recognition membranes by applying an alternative molecular imprinting. The Z‐D‐glutamic acid (D‐Glu) molecularly imprinted membrane adsorbedD‐Glu in preference toL‐glutamic acid (L‐Glu) from racemic mixture of Glu andvice versa. Those two types of molecularly imprinted membrane showed optical resolution ability, adopting a concentration gradient as a driving force for membrane transport. A facile method to predict permselectivity of racemic mixture of charged permeant was proposed. From the observed membrane resistance, the permselectivity was predicted. The predicted permselectivity coincided with the observed one. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Structure and thermomechanical properties of stretched cellulose films
Authors: Kim Jae‐Woo , Park Sunkyu , Harper David P. , Rials Timothy G.
Published: June 2012

Regenerated and stretched cellulose films were investigated for structure and thermomechanical properties as a potential packaging material. Cellulose films were cast from lithium chloride/N, N‐dimethylacetamide and were stretched up to 30% in a dynamic mechanical analyzer sample holder. Wide‐angle X‐ray diffraction analysis indicated that the orientation factor was significantly increased due to stretching. In addition, the stretched films have a higher resistance to the thermal decomposition from thermo gravimetric analysis. The increased orientation of cellulose crystalline structure by the stretching process also increased the storage modulus of cellulose films characterized by dynamic mechanical analysis, which suggest that mechanical properties of cellulose films could be tuned during the stretching process. The α2 and α1 relaxations were found at 240 and 300°C, respectively, which are attributed to the micro‐Brownian motion of segments in amorphous region, and activation energies for relaxations were determined with the stretching levels. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Polypyrrole/MnO2 composites and their enhanced electrochemical capacitance
Authors: Zhang Ai‐Qin , Xiao Yuan‐Hua , Lu Ling‐Zhen , Wang Li‐Zhen , Li Feng
Published: June 2012

The composites of polypyrrole (PPY) and MnO2 have been prepared through chemical oxidation of pyrrole monomer and MnO2 suspension with ammonium peroxysulfate at low temperature. The morphology and structure of materials were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), Transmission electron microscopy (TEM), thermal gravity analysis ‐ differential thermal gravity (TG‐DTG), and X‐ray diffraction (XRD) measurements. The electrochemical properties of the composite were investigated by galvanostatic charge–discharge and electrochemical impedance spectroscopy. The specific capacitance of the composite electrode is 352.8 F/g at a current of 8 mA/cm2 in Na2SO4 electrolyte of 0.5 mol/L, which is much higher than that of 246.2 F/g and 103.5 F/g of PPY and MnO2, respectively. A convenient and effective technique has been developed to fabricate composite materials of PPY and MnO2 promising for designing new capacitors. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Fabrication of a novel polyethylene/starch blend through mediation of a high‐energy ball milling process: Mechanical properties and formation mechanism
Authors: Sharif Alireza , Aalaie Jamal , Shariatpanahi Homeira , Hosseinkhanli Homayoon , Khoshniyat Alireza
Published: June 2012

High‐energy ball milling (HEBM) was performed before melt mixing to fabricate a novel blend containing 85 wt % of a high density polyethylene (HDPE) and 15 wt % of a maize starch, using neither compatibilizer nor plasticizer materials in the blend formulation. Scanning electron microscopy and rheometry results revealed a strong interface between the two phases of the blend. Formation of the interface with high strength was ascribed to the grafting reactions, taking place between the phases during the HEBM process, and corroborated by Fourier transform infrared characterizations. A possible formation mechanism for the starch‐grafted polyethylene was proposed based on the measurements and comprehensive analysis. Interestingly enough, when compared to HDPE mixtures which contained the same amount of the starch, but were made only by conventional melt blending, the ball mill‐mediated sample showed superior mechanical and biodegradation properties. These properties enhancements were related to both the HDPE/starch strong interface and the damaged starch originated by the mechanical action of the milling process. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Antimycobacterial Activity of Pyrimido[4,5‐b]diazepine Derivatives
Authors: Insuasty Braulio , García Angélica , Bueno Juan , Quiroga Jairo , Abonia Rodrigo , Ortiz Alejandro
Published: June 2012

Three series of novel 8,9‐dihydro‐7H‐pyrimido[5,4‐b][1,4]diazepines, 4a–d, 5a–d, and 7a–d, were efficiently obtained in good yields using simple reaction methodologies. These pyrimidodiazepines were evaluated against 15 Mycobacterium spp. strains. Moderate activity in the inhibition of 13 microorganisms was obtained for the four compounds 4a, 5a, 5c, and 5d.
Synthesis and Evaluation of Benzophenone O‐Glycosides as α‐Glucosidase Inhibitors
Authors: Liu Qingchao , Guo Tiantian , Li Wenhong , Li Dong , Feng Zili
Published: June 2012

The first total synthesis of benzophenone O‐glycosides (iriflophenone 2‐O‐α‐L‐rhamnopyranoside: 1 and aquilarisinin: 2) isolated from the leaves of Aquilaria sinensis and related new derivatives (3–12) was accomplished through suitable protecting group manipulations and glycosylation starting from commercially available L‐rhamnose, D‐glucose, D‐galactose, D‐mannose, D‐xylose, and 1,3,5‐trihydroxybenzene. All synthesized benzophenone O‐glycosides were evaluated for their inhibitory activities against α‐glucosidase. Of these, benzophenone O‐glycosides 4 and 10 exhibited the most potent inhibitory activity in vitro against α‐glucosidase with IC50 values of 168.7 ± 13.9 and 210.1 ± 23.9 µM, respectively, when compared with that of the positive control acarbose with an IC50 value of 569.3 ± 49.7 µM.
Synthesis of Mesoporous Platinum–Palladium Alloy Films by Electrochemical Plating in Aqueous Surfactant Solutions
Authors: Wang Hongjing , Yamauchi Yusuke
Published: June 2012

Mesoporous platinum–palladium alloy films with different compositional ratios have been successfully synthesized by electrochemical plating in aqueous surfactant solutions. Scanning electron micrographs and transmission electron micrographs reveal that all of the platinum–palladium alloy films possess uniform mesopores with a narrow size distribution (around 7 nm). The alloy compositions in the pore walls can be controlled by changing the compositional ratios in the precursor solutions, as confirmed by inductively coupled plasma mass spectroscopy analysis and X‐ray photoelectron spectroscopy measurements. Due to large surface areas, the prepared mesoporous platinum–palladium films show distinctly enhanced electrocatalytic activity for methanol oxidation reactions, compared with the commercially available platinum black catalyst. Furthermore, compared with mesoporous platinum film, the alloying of platinum with palladium has a critical effect on the enhanced electrocatalytic activity. In particular, a mesoporous Pt82–Pd18 film exhibits highly enhanced electrocatalytic activity.
A Urea Precursor to Synthesize Carbon Nitride with Mesoporosity for Enhanced Activity in the Photocatalytic Removal of Phenol
Authors: Lee Shu Chin , Lintang Hendrik O. , Yuliati Leny
Published: June 2012

A urea precursor was used for the first time to prepare mesoporous carbon nitride (MCN) by a thermal polymerization process with silica nanospheres as a hard template. Although the prepared MCN samples have similar structures and optical properties, it was revealed that the specific surface area, pore‐size distribution, and morphology of the MCN samples depend on the initial mass ratio of urea to silica. Compared to the bulk carbon nitride (BCN) that only gave 20 % phenol removal (6 h of irradiation), the activities can be enhanced up to 74 % on MCN samples for photocatalytic removal of phenol under visible‐light irradiation. The highest conversion was obtained on MCN with an initial mass ratio of urea to silica of 5, which has high surface area of 191 m2 g−1 and a nanoporous structure with uniform pore‐size distribution of 7 nm. In addition to the high activity, the MCN sample also showed high photocatalytic stability.
Photoluminescence of Alq3‐ and Tb‐activated aluminium–tris(8‐hydroxyquinoline) complex for blue chip‐excited OLEDs
Authors: Yawalkar P. W. , Dhoble S. J. , Thejo Kalyani N. , Atram R. G. , Kokode N. S.
Published: June 2012

The tris(8‐hydroxyquinoline)–aluminium complex is the most important and widely studied as electron transporting and green light emitting material. Alq3 and TbxAl(1‐x)q3 have been synthesized (where x = 0.1, 0.3, 0.5, 0.7 and 0.9) and blended films of Alq3 and TbxAl(1‐x)q3 with PMMA and PS at different percentage weight (wt%) concentrations (e.g., 0.1, 1, 5, 10, 25 and 50 wt%) have been prepared. The synthesized materials and their blended thin films have been characterized by a photoluminescence (PL) technique; the synthesis and PL characterization are reported in this paper. The synthesized metal complex shows bright emission of green light with blue light excitation (440 nm) and the prepared TbxAl(1‐x)q3 phosphor may be applicable in blue chip‐excited OLEDs for the newly developed wallpaper lighting technology. Copyright © 2012 John Wiley & Sons, Ltd.
Synthesis, effect of capping agents and optical properties of manganese‐doped zinc sulphide nanoparticles
Authors: Murugadoss G. , Ramasamy V.
Published: June 2012

Mn2+‐doped ZnS nanoparticles have been successfully synthesized by a chemical precipitation method, using non‐ionic surfactants such as PMMA and PEG. The particles were prepared in an air atmosphere at 80°C. X‐ray diffraction (XRD), transmission electron microscopy (TEM), UV‐visible and photoluminescence (PL) studies were used to investigate the effect of the capping agent on the size, morphology and optical properties of the ZnS–Mn2+ nanoparticles. Enhanced PL was observed from the surfactant‐capped ZnS–Mn2+ nanoparticles. The PL spectra showed a broad blue emission band in the range 460–445 nm and a Mn2+‐related yellow‐orange emission band in the range 581–583 nm. Copyright © 2012 John Wiley & Sons, Ltd.
Amino acids as chiral selectors in enantioresolution by liquid chromatography
Authors: Bhushan Ravi , Dixit Shuchi
Published: June 2012

Amino acids are unique in terms of their structural features and multidimensional uses. With their simple structures and the ready availability of both enantiomers, amino acids not only serve as a chiral pool for synthesis but also provide an inexpensive pool for resolution studies. There has been no attempt to review the application of amino acids as chiral selectors for chromatographic enantioresolution of pharmaceuticals and other compounds. The present paper deals with application of l‐amino acids and complexes of l‐amino acids with a metal ion, particularly Cu(II), as an impregnating reagent in thin‐layer chromatography or as a chiral ligand exchange reagent or a chiral mobile phase additive in both thin‐layer chromatography and high‐performance liquid chromatography. Enantiomeric resolution of β‐blockers, nonsteroidal anti‐inflammatories, amino acids (and their derivatives) and certain other compounds is discussed. Copyright © 2012 John Wiley & Sons, Ltd.
Determination of toosendanin in rat plasma by ultra‐performance liquid chromatography–electrospray ionization–mass spectrometry and its application in a pharmacokinetic study
Authors: Wang Xintang , Wang Changhong , Wang Zhengtao
Published: June 2012

Toosendanin (TSN) is a major triterpenoid existing in Melia toosendan, which has been used as a digestive tract parasiticide and insecticide but with serious hepatotoxicity. An ultra‐performance liquid chromatography–electrospray ionization–mass spectrometry method was developed for determination of TSN in rat plasma. Plasma samples were separated on Acquity UPLCTM BEH C18 column with acetonitrile and water as flow phase by gradient elution and determined by quadrupole mass spectrometer in negative selective ion monitoring mode. Usolic acid was used as internal standard. The calibration curves were linear over 0.02–3.0 µg/mL for TSN with a lower limit of quantification (LLOQ) of 20 ng/mL in rat plasma. The extraction recoveries of TSN were within 74.3–80.7% with an accuracy of 94.5–108.9%. The intra‐ and inter‐day precision values of the assay at three quality control levels were 8.8–13.8% and <13.9% at LLOQ level, respectively. The method was successfully applied to a pharmacokinetic study of TSN in rats after a single intravenous and oral administration of 2 and 60 mg/kg. The shorter Tmax, higher Vd and Cl of TSN after oral administration indicated that TSN could be absorbed, distributed and eliminated quickly in rats in vivo. The absolute bioavailability of TSN after oral administration was 9.9%. Copyright © 2012 John Wiley & Sons, Ltd.
Effect of high glucose on extensive culturing of mesenchymal stem cells derived from subcutaneous fat, omentum fat and bone marrow
Authors: Dhanasekaran M. , Indumathi S. , Rajkumar J. S. , Sudarsanam D.
Published: June 2012

Frontline research progresses the applicability of bone marrow and adipose tissue in regenerative medicine, but fails to account for the functional improvement of the diseased. The justification for the failure in terms of stem cell survival, proliferation and regeneration is unclear. However, hyperglycemia rising during pathological conditions might be one such stumbling block. The prevailing literature accounts for both detrimental and beneficial effect of high glucose on mesenchymal stem cells (MSCs) leading to perplexity. Thus, this study focuses on the effect of high glucose on mesenchymal stem cells derived from subcutaneous fat, omentum fat and bone marrow in extensive cultures. We provide evidence for the retention of MSC characteristics of all sources with regards to surface marker profiling, proliferation, differentiation and karyotyping when cultured extensively under DMEM‐HG containing glucose concentration of 25 mmol.l–1. Thus, it can be concluded that hyperglycemia in vivo (11 mmol.l–1) might not be a barrier for the ineffective functional improvement of transplanted stem cells. Furthermore, we elucidated subcutaneous and omentum fat as better sources of MSCs when compared with bone marrow, thereby making these sources optimal for therapies during hyperglycemic conditions. However, further research is needed to clear the path for efficient stem cell transplantation. Copyright © 2012 John Wiley & Sons, Ltd.
A Multicoincidence Study of Fragmentation Dynamics in Collision of γ‐Aminobutyric Acid with Low‐Energy Ions
Authors: Capron Michael , Díaz‐Tendero Sergio , Maclot Sylvain , Domaracka Alicja , Lattouf Elie , Ławicki Arkadiusz , Maisonny Rémi , Chesnel Jean‐Yves , Méry Alain , Poully Jean‐Christophe , Rangama Jimmy , Adoui Lamri , Martín Fernando , Alcamí Manuel , Rousseau Patrick , Huber Bernd A.
Published: June 2012

Fragmentation of the γ‐aminobutyric acid molecule (GABA, NH2(CH2)3COOH) following collisions with slow O6+ions (v≈0.3 a.u.) was studied in the gas phase by a combined experimental and theoretical approach. In the experiments, a multicoincidence detection method was used to deduce the charge state of the GABA molecule before fragmentation. This is essential to unambiguously unravel the different fragmentation pathways. It was found that the molecular cations resulting from the collisions hardly survive the interaction and that the main dissociation channels correspond to formation of NH2CH2+, HCNH+, CH2CH2+, and COOH+fragments. State‐of‐the‐art quantum chemistry calculations allow different fragmentation mechanisms to be proposed from analysis of the relevant minima and transition states on the computed potential‐energy surface. For example, the weak contribution at [M−18]+, whereMis the mass of the parent ion, can be interpreted as resulting from H2O loss that follows molecular folding of the long carbon chain of the amino acid.
Pd/Light‐Accelerated Atom‐Transfer Carbonylation of Alkyl Iodides: Applications in Multicomponent Coupling Processes Leading to Functionalized Carboxylic Acid Derivatives
Authors: Fusano Akira , Sumino Shuhei , Nishitani Satoshi , Inouye Takaya , Morimoto Keisuke , Fukuyama Takahide , Ryu Ilhyong
Published: June 2012

The atom‐transfer carbonylation reaction of various alkyl iodides thereby leading to carboxylic acid esters was effectively accelerated by the addition of transition‐metal catalysts under photoirradiation conditions. By using a combined Pd/hν reaction system, vicinal C‐functionalization of alkenes was attained in which α‐substituted iodoalkanes, alkenes, carbon monoxide, and alcohols were coupled to give functionalized esters. When alkenyl alcohols were used as acceptor alkenes, three‐component coupling reactions, which were accompanied by intramolecular esterification, proceeded to give lactones. Pd‐dimer complex [Pd2(CNMe)6][PF6]2, which is known to undergo homolysis under photoirradiation conditions, worked quite well as a catalyst in these three‐ or four‐component coupling reactions. In this metal/radical hybrid system, both Pd radicals and acyl radicals are key players and a stereochemical study confirmed the carbonylation step proceeded through a radical carbonylation mechanism.
Ionic‐Liquid‐Derived, Water‐Soluble Ionic Cellulose
Authors: Vo Huyen Thanh , Kim Young Jin , Jeon Eun Hee , Kim Chang Soo , Kim Hoon Sik , Lee Hyunjoo
Published: June 2012

A new type of water‐soluble ionic cellulose was obtained by means of the dissolution of cellulose in dimethylimidazolium methylphosphite at elevated temperatures over 120 °C. FTIR spectroscopy, 1H and 13C NMR spectroscopy, and elemental analysis results revealed that the repeating unit of the water‐soluble cellulose consists of a dialkylimidazolium cation and a phosphite anion bonded to cellulose. The degree of phosphorylation on the cellulose chain was between 0.4 and 1.3 depending on the reaction temperature and time. With an increasing degree of phosphorylation, water solubility was increased. Scanning electron microscopy and X‐ray diffraction analyses revealed that the cellulose crystalline phase in the parent crystalline cellulose changed to an amorphous phase upon transformation into ionic cellulose. Thermogravimetric analysis showed the prepared phosphorylated cellulose was stable over 250 °C and a substantial amount of residue remained at 500 °C.
Large‐Scale Synthesis of High‐Quality Metal Sulfide Semiconductor Quantum Dots with Tunable Surface‐Plasmon Resonance Frequencies
Authors: Kanehara Masayuki , Arakawa Hisamitsu , Honda Tetsuya , Saruyama Masaki , Teranishi Toshiharu
Published: June 2012

High‐quality CdS and Cu7S4 quantum dots (QDs) were synthesized with N,N‐dibutylthiourea (DBTU) as an organic sulfur source. In this method, nucleation and growth reactions were controlled simply by the heating rate of the reaction. The mild oxidation conditions gave monodisperse CdS QDs exhibiting pure band‐edge emission with relatively high photoluminescence quantum yield. During the synthesis of Cu7S4 QDs, the addition of dodecanethiol to the reaction system controlled the reaction rate to give monodisperse spherical or disk‐shaped QDs. A hundred‐gram scale of copper precursor could be used to generate the high‐quality Cu7S4 QDs, indicating that an industrial‐scale reaction is achievable with our method. As observed in anisotropic noble‐metal nanocrystals, larger disk‐shaped Cu7S4 QDs showed lower localized‐surface‐plasmon resonance energy in the near‐infrared region. The disk‐shaped Cu7S4 QDs could be used effectively as templates to form cation‐exchanged monodisperse disk‐shaped CdS QDs.
Enantioselective Toxic Effects of Hexaconazole Enantiomers Against Scenedesmus Obliquus
Authors: Huang Ledan , Lu Dahai , Zhang Ping , Diao Jinling , Zhou Zhiqiang
Published: June 2012

Enantioselectivity in ecotoxicity of chiral pesticides in the aquatic environment has been a subject of growing interest. In this study, the toxicological impacts of hexaconazole enantiomers were investigated with freshwater algae Scenedesmus obliquus. After 96 h of exposure, the EC50 values for rac‐hexaconazole, (+)‐hexaconazole, and (−)‐hexaconazole were 0.178, 0.355, and 0.065 mg l−1, respectively. Therefore, the acute toxicities of hexaconazole enantiomers were enantioselective. In addition, the different toxic effects were evaluated when S. obliquus were exposed to 0.2, 0.5, and 1.0 mg l−1 of rac‐hexaconazole, (+)‐hexaconazole, and (−)‐hexaconazole during 96 h, respectively. The chlorophyll a and chlorophyll b contents of S. obliquus treated by (−)‐hexaconazole were lower than those exposed to (+)‐hexaconazole, whereas the malondialdehyde contents of S. obliquus treated by (−)‐form were higher than those exposed to (+)‐form at higher concentrations. In general, catalase activities were significantly upregulated by exposure to (−)‐enantiomer than (+)‐enantiomer at all three concentrations. However, superoxide dismutase activities exposed to (−)‐hexaconazole were lower than that exposed to (+)‐hexaconazole at 0.2 mg l−1 and 0.5 mg l−1. On the basis of these data, the acute toxicity and toxic effects of hexaconazole against S. obliquus were enantioselective, and such enantiomeric differences must be taken into consideration in pesticide risk assessment. Chirality 24:610–614, 2012. © 2012 Wiley Periodicals, Inc.
Oreganum Stalks as a New Biosorbent to Remove Textile Dyes from Aqueous Solutions
Authors: Mavioglu Ayan Ebru , Secim Pelin , Karakaya Serhat , Yanik Jale
Published: June 2012

In the present study, Oreganum onites L. stalks in natural and chemically modified with HNO3 and H3PO4 used as adsorbent for removal of both acidic and basic dyes from waters. The adsorption was studied as a function of pH and contact time by batch method. All tested biosorbents were characterized by FT‐IR, scanning electron microscopy, and measuring the pH dependence of the zeta potential. The adsorption isotherms were fitted to Langmuir isotherm. The maximum adsorption capacity of dyes was 280.73 mg g−1 for Basic Red 18, 147.06 mg g−1 for methylene blue and 112.36 for Acid Red 111, which is comparable to that of other lignocellulosic materials. The modification process was considerably increased the biosorption capacity of lignocellulosic material, resulting in a 56–63% increase in the biosorption capacity of basic dyes and a 125% increase in the biosorption capacity of acidic dye. The present study illustrated that the most effective factors in the adsorption of basic dye were surface charge and acidic groups on lignocellulosic biosorbents, while non‐electrostatic forces as well as electrostatic forces were also effective in the adsorption of acidic dye. In conclusion, Oreganum stalks can be considered as a very prospective adsorbent for the removal of tested basic and acidic dyes.
Fat or fit: The joint effects of physical activity, weight gain, and body size on breast cancer risk
Authors: McCullough Lauren E. , Eng Sybil M. , Bradshaw Patrick T. , Cleveland Rebecca J. , Teitelbaum Susan L. , Neugut Alfred I. , Gammon Marilie D.
Published: June 2012

BACKGROUND:

Although physical activity reduces breast cancer risk, issues critical to providing clear public health messages remain to be elucidated. These include the minimum duration and intensity necessary for risk reduction and the optimal time period for occurrence, as well as subgroup effects, particularly with regard to tumor heterogeneity and body size.

METHODS:

This study investigated the relationship between recreational physical activity (RPA) and breast cancer risk, in addition to characterizing the joint effects of activity level, weight gain, and body size, through use of a population‐based sample of 1504 cases (N = 233 in situ, N = 1271 invasive) and 1555 controls (aged 20‐98 years) from the Long Island Breast Cancer Study Project, in Long Island, New York.

RESULTS:

A nonlinear dose‐response association was observed between breast cancer risk and RPA during the reproductive period and after menopause. Women in the third quartile of activity experienced the greatest benefit with an approximate 30% risk reduction for reproductive (odds ratio = 0.67; 95% confidence interval = 0.48‐0.94) and postmenopausal activity (odds ratio = 0.70; 95% confidence interval = 0.52‐0.95). Little to no difference was observed regarding intensity of activity or hormone receptor status. Joint assessment of RPA, weight gain, and body size revealed that women with unfavorable energy balance profiles were at increased breast cancer risk. A significant multiplicative interaction was observed between RPA and adult weight gain (P = .033).

CONCLUSIONS:

RPA at any intensity level during the reproductive and postmenopausal years have the greatest benefit for reducing breast cancer risk. Substantial postmenopausal weight gain may eliminate the benefits of regular activity. Cancer 2012. © 2012 American Cancer Society.
Analyzing individual and group differences in multijoint multiwaveform gait data using the Parafac2 model
Authors: Helwig Nathaniel E. , Hong Sungjin , Bokhari Ehsan
Published: June 2012

Locomotion research often involves analyzing multiwaveform data (e.g., velocities, accelerations, etc.) from various body locations (e.g., knees, ankles, etc.) of several subjects. Therefore, some multivariate technique such as principal component analysis is often used to examine interrelationships between the many correlated waveforms. Despite its extensive use in locomotion research, principal component analysis is for two‐mode data, whereas locomotion data are typically collected in higher mode form. In this paper, we present the benefits of analyzing four‐mode locomotion data (subjects × time × joints × waveforms) using the Parafac2 model, which is a component model designed for analyzing variation in multimode data. Using bilateral hip, knee, and ankle angular displacement, velocity, and acceleration waveforms, we demonstrate Parafac2's ability to produce interpretable components describing (i) the fundamental patterns of variation in lower limb angular kinematics during healthy walking and (ii) the fundamental differences between normal and atypical subjects’ multijoint multiwaveform locomotive patterns. Also, we illustrate how Parafac2 makes it possible to determine which waveforms best characterize the individual and/or group differences captured by each component. Our results indicate that different waveforms should be used for different purposes, confirming the need for the holistic analysis of multijoint multiwaveform locomotion data, particularly when investigating atypical motion patterns. Copyright © 2012 John Wiley & Sons, Ltd.
Mechanics of the foot Part 1: A continuum framework for evaluating soft tissue stiffening in the pathologic foot
Authors: Fernandez J.W. , Ul Haque M.Z. , Hunter P.J. , Mithraratne K.
Published: June 2012

Soft tissue stiffening is a common mechanical observation reported in foot pathologies including diabetes mellitus and gout. These material changes influence the spatial distribution of stress and affect blood flow, which is essential to nutrient entry and waste removal. An anatomically‐based subject‐specific foot model was developed to explore the influence of tissue stiffening on plantar pressure and internal von Mises stress at heel‐strike, midstance and toe‐off. This work draws on the model database developed for the Physiome project consisting of muscles, bones, soft tissue and other structures such as sensory nerves. The anisotropic structure of soft tissue was embedded in a single continuum as an efficient model for finite soft tissue deformation, and customisation methods were used to capture the unique foot profile. The model was informed by kinetics from an instrumented treadmill and kinematics from motion capture, synchronised together. Foot sole pressure predictions were evaluated against a commercial pressure platform. Key outcomes showed that internal stress can be up to 1.6 times the surface pressure with implications for internal soft tissue damage not observed at the surface. The main nerve branch stimulated during gait was the lateral plantar nerve. This subject‐specific modelling framework can play an integral part in therapeutic treatments by informing assistive strategies such as mechanical noise stimulation and orthotics. Copyright © 2012 John Wiley & Sons, Ltd.
Inspiration from nature: dynamic modelling of the musculoskeletal structure of the seahorse tail
Authors: Praet Tomas , Adriaens Dominique , Cauter Sofie Van , Masschaele Bert , Beule Matthieu De , Verhegghe Benedict
Published: June 2012

Technological advances are often inspired by nature, considering that engineering is frequently faced by the same challenges as organisms in nature. One such interesting challenge is creating a structure that is at the same time stiff in a certain direction, yet flexible in another. The seahorse tail combines both radial stiffness and bending flexibility in a particularly elegant way: even though the tail is covered in a protective armour, it still shows sufficient flexibility to fully function as a prehensile organ. We therefore study the complex mechanics and dynamics of the musculoskeletal system of the seahorse tail from an engineering point of view. The seahorse tail derives its combination of flexibility and resilience from a chain of articulating skeletal segments. A versatile dynamic model of those segments was constructed, on the basis of automatic recognition of joint positions and muscle attachments. Both muscle structures that are thought to be responsible for ventral and ventral–lateral tail bending, namely the median ventral muscles and the hypaxial myomere muscles, were included in the model. Simulations on the model consist mainly of dynamic multi‐body simulations. The results show that the sequential structure of uniformly shaped bony segments can remain flexible because of gliding joints that connect the corners of the segments. Radial stiffness on the other hand is obtained through the support that the central vertebra provides to the tail plating. Such insights could help in designing biomedical instruments that specifically require both high bending flexibility and radial stiffness (e.g. flexible stents and steerable catheters).Copyright © 2012 John Wiley & Sons, Ltd.
Spring‐network‐based model of a red blood cell for simulating mesoscopic blood flow
Authors: Nakamura Masanori , Bessho Sadao , Wada Shigeo
Published: June 2012

We developed a mechanical model of a red blood cell (RBC) that is capable of expressing its characteristic behaviors in shear flows. The RBC was modeled as a closed shell membrane consisting of spring networks in the framework of the energy minimum concept. The fluid forces acting on RBCs were modeled from Newton's viscosity law and the conservation of momentum. In a steady shear flow, the RBC model exhibited various behaviors, depending on the shear rate; it tumbled, tank‐treaded, or both. The transition from tumbling to tank‐treading occurred at a shear rate of 20 s − 1. The simulation of an RBC in steady and unsteady parallel shear flows (Couette flows) showed that the deformation parameters of the RBC were consistent with experimental results. The RBC in Poiseuille flow migrated radially towards the central axis of the flow channel. Axial migration became faster with an increase in the viscosity of the media, qualitatively consistent with experimental results. These results demonstrate that the proposed model satisfies the essential conditions for simulating RBC behavior in blood flow. Finally, a large‐scale RBC flow simulation was implemented to show the capability of the proposed model for analyzing the mesoscopic nature of blood flow. Copyright © 2012 John Wiley & Sons, Ltd.
Cooperative and reactive scheduling in large‐scale virtualized platforms with DVMS
Authors: Quesnel Flavien , Lèbre Adrien , Südholt Mario
Published: June 2012

One of the principal goals of cloud computing is the outsourcing of the hosting of data and applications, thus enabling a per‐usage model of computation. Data and applications may be packaged in virtual machines (VM), which are themselves hosted by nodes, that is, physical machines. Several frameworks have been designed to manage VMs on pools of physical machines; most of them, however, do not efficiently address a major objective of cloud providers: maximizing system utilization while ensuring the QoS. Several approaches promote virtualization capabilities to improve this trade‐off. However, the dynamic scheduling of a large number of VMs as part of a large distributed infrastructure is subject to important and hard scalability problems that become even worse when VM image transfers have to be managed. Consequently, most current frameworks schedule VMs statically using a centralized control strategy. In this article, we present distributed VM scheduler, a framework that enables VMs to be scheduled cooperatively and dynamically in large‐scale distributed systems. We describe, in particular, how several VM reconfigurations can be dynamically calculated in parallel and applied simultaneously. Reconfigurations are enabled by partitioning the system (i.e., nodes and VMs) on the fly. Partitions are created with a minimum of resources necessary to find a solution to the reconfiguration problem. Moreover, we propose an algorithm to handle deadlocks that may appear because of the partitioning policy. We have evaluated our prototype through simulations and compared our approach with a centralized one. The results show that our scheduler permits VMs to be reconfigured more efficiently: the time needed to manage thousands of VMs on hundreds of machines is typically reduced to a tenth or less. Copyright © 2012 John Wiley & Sons, Ltd.
Postfunctionalization of Helical Polyisocyanopeptides with Phthalocyanine Chromophores by “Click Chemistry”
Authors: López‐Duarte Ismael , Martínez‐Díaz M. Victoria , Schwartz Erik , Koepf Matthieu , Kouwer Paul H. J. , Rowan Alan E. , Nolte Roeland J. M. , Torres Tomás
Published: June 2012

Rigid rod polyisocyanopeptides bearing phthalocyanines as pendant groups have been synthesised through CuAAC of polyisocyanopeptides containing acetylene groups with zinc(II) phthalocyanine azide. As confirmed by UV/Vis, fluorescence, and circular dichroism spectroscopies, the phthalocyanines are arranged in a helical fashion along the polymer backbone, forming the longest reported well‐defined phthalocyanine assembly described to date.
Towards quantification of the role of materials innovation in overall technological development
Authors: Magee Christopher L.
Published: June 2012

This article presents a method for quantitatively assessing the role of materials innovation in overall technological development. The method involves classifying the technical changes underlying the overall innovation process first within a set of functional categories and then within each category as a hierarchical array of technical changes. It is specifically found that about 2/3 of the total progress in computation over the past 40 years has been due to materials/process innovations. More speculatively, materials/process innovation contributes at least 20% of the progress in all areas and the relative contribution of materials/process innovation to overall technological progress has grown in the past few decades. © 2012 Wiley Periodicals, Inc. Complexity, 2012
Study on the algorithms to correct and compensate for GLONASS signal deviation based on GNSS receiver
Authors: Ma Hongbin , Xu Wennian , Liu Xinrui , Hu Qiling , Huang Xiang
Published: June 2012

At present, because of the construction of the navigation and positioning systems such as the China BeiDou, the research on complex receivers has become very urgent and active. This paper reports on the compatibility of the combined GPS and GLONASS data processing system. Because of the Frequency Division Multiple Access (FDMA) access technique applied in GLONASS satellites, while different signals of GLONASS satellites pass through different parts of the Radio Frequency (RF), the group delay effect can appear. Especially, if the hardware design of the base station and rover station are different, the problem is more severe. Aimed at these issues, the reasons and conditions are studied and then the comprehensive correction methods of deviation are proposed such as: effective real‐time pseudorange and carrier phase deviation correction compensation; tracking GLONASS L2 signal; establishing a eceiver name database; base station providing the receiver name; rover station correcting deviation according to different base stations, and so on. Through the use of schemes and algorithms, the objective existence GLONASS deviation can be reduced, and the capacity of the GPS+GLONASS complex system can be improved. It is also demonstrated that if the base station receiver and rover are from different manufactures, the deviation from GLONASS pseudorange and carrier phase can lead to the failure of achieving centimeter level. With the algorithms, in all the applications and in any base station or networked system, the GPS+GLONASS complex system can exhibit the advantages over just GPS applied system both in positioning accuracy and positioning speed and other real‐time kinematic (RTK) positioning performance. Copyright © 2012 John Wiley & Sons, Ltd.
Performance improvement of hybrid tag anti‐collision protocol for radio frequency identification systems
Authors: Kim Soo‐Cheol , Cho Jung‐Sik , Kim Sung‐Kwon
Published: June 2012

Radio frequency identification (RFID), a new technology for the contactless recognition of objects, is considered an ideal solution to replace barcode systems. To make RFID technology widely applicable, it is important to resolve the ‘multiple tag identification problems’, that is, the problem of indicating tag collisions occurring when multiple RFID tags are simultaneously present in a reader's field. The proposed anti‐collision algorithm in this paper consists of two separate phases: distribution and recognition. The algorithm distributes tags to be read in such a way that tag collisions are reduced. In the distribution phase, the conventional ALOHA algorithm is used with a newly added command. When there are several occurrences of collision or no‐response in a round, a new round is initiated by adjusting the frame size on the basis of the estimated number of tags. ALOHA‐based algorithms have the weakness of not being able to guarantee a 100% tag identification rate. Hence, the proposed algorithm uses a tree‐based algorithm in the recognition phase in order to eliminate this problem. In addition, the reversed ID approach is employed to ensure efficient tag identification. The simulation results show that the proposed algorithm takes less tag identification time than the conventional algorithms, thereby increasing RFID system efficiency. Copyright © 2012 John Wiley & Sons, Ltd.
Ontogeny and sex alter the effect of predation on body shape in a livebearing fish: sexual dimorphism, parallelism, and costs of reproduction
Authors: Hassell Elizabeth M. A. , Meyers Peter J. , Billman Eric J. , Rasmussen Josh E. , Belk Mark C.
Published: June 2012

Predation can cause morphological divergence among populations, while ontogeny and sex often determine much of morphological diversity among individuals. We used geometric morphometrics to characterize body shape in the livebearing fish Brachyrhaphis rhabdophora to test for interactions between these three major shape‐determining factors. We assessed shape variation between juveniles and adults of both sexes, and among adults for populations from high‐ and low‐predation areas. Shape differed significantly between predation regimes for all juveniles regardless of sex. As males grew and matured into adults, ontogenetic shape trajectories were parallel, thus maintaining shape differences in adult males between predation environments. However, shape of adult females between predation environments followed a different pattern. As females grew and matured, ontogenetic shape trajectories converged so that shape differences were less pronounced between mature females in predator and nonpredator environments. Convergence in female body shape may indicate a trade‐off between optimal shape for predator evasion versus shape required for the livebearing mode of reproduction.
Cooperation of Th1 and Th17 cells determines transition from autoimmune myocarditis to dilated cardiomyopathy
Authors: Nindl Veronika , Maier Reinhard , Ratering David , De Giuli Rita , Züst Roland , Thiel Volker , Scandella Elke , Di Padova Franco , Kopf Manfred , Rudin Markus , Rülicke Thomas , Ludewig Burkhard
Published: June 2012

Myocarditis is a potentially lethal inflammatory heart disease of children and young adults that frequently leads to dilated cardiomyopathy (DCM). Since diagnostic procedures and efficient therapies are lacking, it is important to characterize the critical immune effector pathways underlying the initial cardiac inflammation and the transition from myocarditis to DCM. We describe here a T‐cell receptor (TCR) transgenic mouse model with spontaneously developing autoimmune myocarditis that progresses to lethal DCM. Cardiac magnetic resonance imaging revealed early inflammation‐associated changes in the ventricle wall including transient thickening of the left ventricle wall. Furthermore, we found that IFN‐γ was a major effector cytokine driving the initial inflammatory process and that the cooperation of IFN‐γ and IL‐17A was essential for the development of the progressive disease. This novel TCR transgenic mouse model permits the identification of the central pathophysiological and immunological processes involved in the transition from autoimmune myocarditis to DCM.