bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polyurethane thermoplastic elastomers with inherent radiopacity for biomedical applications
Authors: Kiran S. , James Nirmala R. , Jayakrishnan A. , Joseph Roy 
Published: July 2012

AbstractSynthesis and characterization of three different radiopaque thermoplastic polyurethane elastomers are reported. Radiopacity was introduced to the polyurethanes by incorporating an iodinated chain extender, namely, 4,4′‐isopropylidinedi‐(2,6‐diiodophenol) (IBPA), into the polymer chain during polyurethane synthesis. Radiopaque polyurethanes (RPUs) were synthesized by reacting 4,4′‐methylenebis(phenyl isocyanate) (MDI), IBPA, and three different diols. The polyols used for the synthesis were polypropylene glycol, polycaprolactone diol, and poly(hexamethylene carbonate) diol. RPUs were characterized by infrared spectroscopy, contact angle measurements, thermogravimetry, dynamic mechanical analysis, energy dispersive X‐ray analysis, gel permeation chromatography, X‐ray fluorescence spectroscopy, and X‐radiography. X‐ray images showed that all RPUs prepared using IBPA as the chain extender are highly radiopaque compared with an Aluminum wedge of equivalent thickness. Elemental analysis revealed that the polyurethanes contained 18–19% iodine in the polymer matrix. The RPUs developed have radiopacity equivalent to that of a polymer filled with 20 wt % barium sulfate. Results revealed that RPUs of wide range of properties may be produced by incorporating different diols as the soft chain segment. Cell culture cytotoxicity studies conducted using L929 cells by direct contact test and MTT assay proved that these RPUs are noncytotoxic in nature. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2012.
Temporal and spatial analyses of temperature in a French wine‐producing area: the Loire Valley
Authors: Bonnefoy C. , Quenol H. , Bonnardot V. , Barbeau G. , Madelin M. , Planchon O. , Neethling E. 
Published: July 2012

AbstractGlobal warming is causing earlier phenological dates for vines and changes in the quality of wines all around the world. To understand how vines are liable to react to future climate evolution, the climate of viticultural areas needs to be known as accurately as possible. In this article, temporal evolution and spatial variability of temperature in the wine producing area of the Loire Valley were analysed with a multi‐scalar approach. First, the regional evolution of temperature and bioclimatic indices were studied over the past 60 years in the wine‐producing area of the Loire Valley and showed a general warming at all locations in the regional weather station network (Météo‐France). Secondly, temperature data from weather stations located within the vineyards between Angers and Saumur were studied for the year 2010 and underlined spatial variability of temperature between the different plots according to the different topoclimates. Finally, particular attention was paid to theCoteaux du Layonvineyards (sweet wine producing appellation) where 21 temperature data loggers were set up in the vine rows to study climate at local scale. The study showed, in particular, that the spatial variability of temperature and bioclimatic indices in these vineyards was greater than those observed at larger scales. Copyright © 2012 Royal Meteorological Society
Temperature changes in the mid‐ and high‐ latitudes of the Southern Hemisphere
Authors: Richard Y. , Rouault M. , Pohl B. , Crétat J. , Duclot I. , Taboulot S. , Reason C. J. C. , Macron C. , Buiron D. 
Published: July 2012

AbstractA Hierarchical Ascending Classification is used to regionalize monthly temperature anomalies measured at 24 weather stations in Antarctica and the Sub‐Antarctic and mid‐latitude southern islands from 1973 to 2002. Three principal regions are identified that are geographically coherent: Eastern Antarctica, the Antarctic Peninsula and the Sub‐Antarctic and mid‐latitude islands. Within each region, consistent trends are observed: namely, stationary temperatures in ‘East‐Antarctica’; a robust warming in the ‘Sub‐Antarctic and mid‐latitude islands’, most pronounced in austral summer (nearly 0.5 °C per decade); and a strong but more recent warming in the ‘Antarctic Peninsula’. Austral summer temperature anomalies are related to (1) the Southern Annular Mode (SAM) indexes computed using two reanalysis products (20th Century Reanalyses and ERA40) over two periods (1958–2002 and 1973–2002), (2) the seasonal frequencies of four recurrent daily weather regimes identified with a k‐means algorithm applied on the 500hPa geopotential height (DJF 1958–2002) and (3) HadSST2 sea surface temperature (SST) anomalies (DJF 1958–2002). East‐Antarctica interannual temperature anomalies are associated with the SAM variability. In the Antarctic Peninsula, only the long‐term trend is common with the SAM. The SAM does impact significantly the temperature anomalies of the Sub‐Antarctic and mid‐latitude islands. Trend and interannual variability of the islands' temperatures are associated with the nearby SST. For the Indian Ocean stations, warming in the Agulhas Current system could also have led to these changes. Copyright © 2012 Royal Meteorological Society
The Domestic Camelids (Cetartiodactyla: Camelidae) from the Middle Formative Cemetery of Topater 1 (Atacama Desert, Northern Chile): Osteometric and Palaeopathological Evidence of Cargo Animals
Authors: Labarca R. , Gallardo F. 
Published: July 2012

AbstractThe Middle Formative Cemetery of Topater 1 (ca. 500 bc–100 ad), located in the oasis of Calama, Northern Chile, presents an unusually diverse array and quantity of funerary offerings, distributed among the graves of more than 200 individuals. Among the offerings are the remains of several mummified camelids and camelid skeletal elements, primarily distal extremities and artefacts made from the bones of these animals. Taking only the first skeletonised anterior and posterior phalanges of Topater 1 camelids, we conducted univariate and multivariate osteometric analyses in order to assign the sample to the appropriate taxonomic groups. At the same time, we described all osteopathologies registered for the extremities in the collection. Of the 45 phalanges measured, 30 were of similar or greater size than contemporary reference llamas. Fourteen of the 164 samples of bone extremities presented pathologies, most of them first phalanges. These abnormalities included different degrees of exostosis and, less commonly, eburnation and lipping. Considering both lines of evidence, we conclude that the llamas sacrificed at the Topater 1 cemetery correspond to, at least, two very large and robust cargo llama morphotypes. When living, these animals would have transported goods as part of the intense exchange activity that was taking place during this period in the region extending from the Pacific coast to Northwest Argentina and perhaps even beyond. Copyright © 2012 John Wiley & Sons, Ltd.
The deformation behavior of polypropylene film under high strain rates
Authors: Tokihisa Masayoshi , Kushizaki Yoshiyuki , Tomiyama Hideki , Umeda Yuki , Yamada Toshiro 
Published: July 2012

AbstractThe relationship between stress and strain for polypropylene film was studied under strain rates from 0.13 to 5.21 s−1 in order to study the deformation behavior of film under higher strain rates than previous studies. Uniform thickness was obtained in the strain rates from 2.08 to 5.21 s−1 at 435 K, or from 2.08 to 3.13 s−1 at 437 K. The temperature rise of film due to the generation of heat from plastic strain influenced the relationship between stress and strain, in particular, at high strain rates and low temperature. Material constants for the constitutive equation of film were determined using the measurements from 2.08 to 5.21 s−1 at 435 K and from 2.08 to 3.13 s−1 at 437 K. Film thicknesses during and after transverse direction stretching were successfully predicted by applying the material constants obtained. The authors concluded that the material constants should be determined by applying the stretching conditions, under which there is little or no effect from heat generation and under which film can be stretched uniformly in thickness. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Phthalonitrile‐containing poly(amide imide)s with nanoactuation properties
Authors: Hamciuc Elena , Hamciuc Corneliu , Carja Ionela‐Daniela , Vlad‐Bubulac Tachita , Ignat Mircea 
Published: July 2012

AbstractA series of aromatic poly(amide imide)s containing pendant phthalonitrile groups was prepared by solution polycondensation reaction of 4,4′‐diamino‐4″‐(3,4‐dicyanophenoxy)triphenylmethane, 1, or of different amounts of 1 and 1,3‐bis(4‐aminophenoxy)benzene, with a fluorinated imide diacid chloride, 2,2‐bis[N‐(4‐chloroformylphenyl)phthalimidyl]hexafluoroisopropane. The polymers were easily soluble in polar organic solvents, such as N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, N,N‐dimethylformamide, and dimethylsulfoxide. They can be cast from solutions into thin flexible films showing nanoactuation properties in the range of 120–450 nm, depending on the nitrile group content, when an electric voltage is applied on their surface. Electrical insulating properties of the polymer films were evaluated on the basis of dielectric permittivity and dielectric loss and their variation with the frequency and temperature. The values of the dielectric permittivity at 10 kHz and 20°C were in the range of 3.01–3.43. All polymers exhibited high thermal stability, decomposition temperature being above 420°C. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Kinetic finite element model to optimize sulfur vulcanization: Application to extruded epdm weather‐strips
Authors: Milani G. , Milani F. 
Published: July 2012

AbstractA numerical two‐phase approach based on experimental scorch curve data fitting, to predict the optimal exposure time and cure temperature of extruded thick items is applied for the study of a real weather‐strip. In the first phase, an existing single equation kinetic model is used to predict the crosslinking density under sulfur vulcanization at variable temperatures. The model requires the calibration of only three kinetic constants. The variation with respect to temperature of such parameters is then evaluated by means of two experimental cure curves performed at two different temperatures. In the second phase, kinetic reaction parameters are implemented in finite element software, to perform thermal analyses on an extruded weather‐strip. Once evaluated the final mechanical properties of the item point by point, a set of compression tests is numerically simulated, assuming that the rubber behaves as a Mooney–Rivlin material under the large deformations. Elastic properties of the item are evaluated as a function of the vulcanization degree evaluated in the second phase. It is found that suboptimal vulcanizations result into lower elastic moduli and hence great deformability, sometimes incompatible with real scale engineering applications. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Syntheses and properties of dumbbell‐shaped POSS derivatives linked by luminescent π‐conjugated units
Authors: Araki Hitoshi , Naka Kensuke 
Published: July 2012

AbstractDumbbell‐shaped isobutyl‐substituted 1,2‐bis(4‐vinylphenyl)acetylene‐linked POSS (DA1), 9,10‐bis(4‐vinylphenyl)ethynyl)anthracene‐linked POSS (DA2), and 5,5″‐bis((4‐vinyl)phenyl)ethynyl)‐2,2′:5′2″‐terthiophene‐linked POSS (DA3), and corresponding model compounds were synthesized by cross metathesis and Sonogashira reaction, and their film formability, and thermal and optical properties were examined. The dumbbell structures of the obtained compounds were confirmed by 1H‐, 13C‐, and 29Si‐NMR and MALDI‐TOF‐MS analysis. The dumbbell‐shaped POSS compounds gave optically transparent films. All the model compounds, however, formed opaque films. All the films were emissive under UV irradiation. The dumbbell structures minimize longer wavelength shifts and improve emission efficiency of the luminescent π‐conjugated linker units in their solid states compared with the model compounds. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012.
Polymer electrolyte membranes based on polystyrenes with phosphonic acid via long alkyl side chains
Authors: Tamura Youko , Sheng Li , Nakazawa Satoshi , Higashihara Tomoya , Ueda Mitsuru 
Published: July 2012

AbstractA series of polystyrenes with phosphonic acid (5) via long alkyl side chains (4, 6, and 8 methylene units) were prepared by the radical polymerization of the corresponding diethyl ω‐(4‐vinylphenoxy)alkylphosphonates, followed by the hydrolysis with trimethylsilyl bromide. The resulting phosphonated polystyrene membranes had a high oxidative stability against Fenton's reagent at room temperature. The membranes prepared from 5 exhibited a very low water uptake, similar to that of Nafion 117 over the wide range of 30 to 80% relative humidity (RH). The proton conductivities of these membranes are lower than that of Nafion 117 in the range of 30 to 90% RH, but comparable or higher than those of the reported phosphonated polymers with higher IEC values, such as the phosphonated poly(N‐phenylacrylamide) (PDPAA, IEC: 6.72 mequiv/g) and fluorinated polymers with pendant phosphonic acids (M47, IEC: 8.5 mequiv/g), at low RH conditions despite the much lower IEC values (3.0–3.8 mequiv/g) of these membranes. These results suggest that the flexible pendant side chains of 5 would contribute to the formation of hydrogen‐bonding networks by considering the very low water uptake of these polymers. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
RAFT‐mediated synthesis of poly[(oligoethylene glycol) methyl ether acrylate] brushes for biological functions
Authors: Zengin Adem , Caykara Tuncer 
Published: July 2012

AbstractThe synthesis of poly[(oligoethylene glycol) methyl ether acrylate] [poly(OEGA)] brushes was achieved via reversible addition‐fragmentation chain transfer (RAFT) polymerization and used to selectively immobilize streptavidin proteins. Initially, gold surfaces were modified with a trithiocarbonate‐based RAFT chain transfer agent (CTA) by using an ester reaction involving a gold substrate modified with 11‐mercapto‐1‐undecanol and bis(2‐butyric acid)trithiocarbonate. poly(OEGA) brushes were then prepared via RAFT‐mediated polymerization from the surface‐immobilized CTA. The immobilization of CTA on the gold surface and the subsequent polymer formation were followed by ellipsometry, X‐ray photoelectron spectroscopy, grazing angle‐Fourier transform infrared spectroscopy, atomic force microscopy, and water contact‐angle measurements. RAFT‐mediated polymerization method gave CTA groups to grafted poly(OEGA) termini, which can be converted to various biofunctional groups. The terminal carboxylic acid groups of poly(OEGA) chains were functionalized with amine‐functionalized biotin units to provide selective attachment points for streptavidin proteins. Fluorescence microscopy measurements confirmed the successful immobilization of streptavidin molecules on the polymer brushes. It is demonstrated that this fabrication method may be successfully applied for specific protein recognition and immobilization. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Structural and Thermal Characterization of A Novel High Nitrogen Energetic Material: (NH4)2DNMT
Authors: Xu Kang‐Zhen , Zhang Hang , Liu Ping , Huang Jie , Ren Ying‐Hui , Wang Bo‐Zhou , Zhao Feng‐Qi 
Published: July 2012

Abstract1,4‐Dihydro‐5H‐(dinitromethylene)‐tetrazole ammonium salt ((NH4)2DNMT), a high nitrogen energetic compound, was synthesized and structurally characterized by single‐crystal X‐ray diffraction. The thermal behavior of (NH4)2DNMT was studied with DSC and TG‐DTG methods. The kinetic equation of the thermal decomposition reaction is: dα/dT=1013.17/3β(1−α)−2 exp(−1.388×105/RT). The critical temperature of thermal explosion is 182.7 °C. The specific heat capacity of (NH4)2DNMT was determined and the molar heat capacity is 301 J mol−1 K−1 at 298.15 K. The adiabatic time‐to‐explosion of (NH4)2DNMT was calculated to be 277 s. The detonation velocity and detonation pressure were also estimated. All results showed that (NH4)2DNMT presents good performance.
Nanodiamond‐therapeutic complexes embedded within poly(ethylene glycol) diacrylate hydrogels mediating sequential drug elution
Authors: Man Han B. , Lam Robert , Chen Mark , Osawa Eiji , Ho Dean 
Published: July 2012

AbstractThe versatility of nanodiamonds (NDs) as a polymer‐embedded therapeutic vehicle was demonstrated by the development of a hybrid material consisting of a poly(ethylene glycol) diacrylate (PEGDA) hydrogel embedded with ND‐drug complexes. A wide range of PEGDA structures, including single and multiple drug reservoirs, exhibited high loading capabilities and stable slow‐release, augmented with the addition of ND conjugates. ND‐PEGDA hydrogels were compared to unmodified, drug‐embedded PEGDA hydrogels to demonstrate their robust drug sequestering capacity in vitro. Remarkably, ND‐embedded hydrogels were capable of mitigating the harmful effects of burst‐release by displaying slow and controlled administration of therapeutic compounds, an improvement over standard diffusion‐based release profiles. The tunable customization of PEGDA hydrogel, both in structure and content, as well as its facile methods of synthesis, make this material an effective multi‐therapeutic complement to the drug delivery abilities of NDs. A hybrid material that utilizes the synergy of PEGDA and ND components has the potential for applications toward a diverse array of biomedical challenges. magnified imageAn artistic rendering of a multi‐layered PEGDA patch. The center of the patch (purple) contains drug‐bound ND particles that are being released (gray truncated octahedra with purple glow), while the outer ring depicts the molecule Temozolomide (green). This image illustrates the ability for tiered patches to simultaneously administer multiple drugs, as well as the drug‐sequestering ability of NDs that mediates sustained delivery and reduced burst release. The nested structure of the two drugs was designed so that the therapeutics could be released sequentially, at different peak‐elution time intervals.
Giant dielectric and ferromagnetic response in Ba0.4Sr0.6Ti1−yCoyO3 ceramics
Authors: Zhang Jingji , Liu Jintao , Huang Xia , Lin Xuecheng , Wang Jiangying 
Published: July 2012

AbstractBa0.4Sr0.6Ti1−yCoyO3 ceramics show a diphase of Ba1−xSrxTiO3 and 6H‐hexagonal BaTi1−yCoyO3. As y increases, Ba0.4Sr0.6Ti1−yCoyO3 ceramics experience a transformation from ferroelectric to relaxor‐like behavior. For the samples with y ≥ 0.10, the dielectric constant exhibits relaxor‐like behavior with the frequency‐dependent temperature of the dielectric peak Tm following an Arrhenius law, accompanying a giant dielectric response. The dielectric relaxation with an extremely high dielectric peak is attributed to charge ordering and defects. The samples with low Co levels (y ≤ 0.05) exhibit dielectric nonlinear behavior, whereas those with high Co levels (y ≥ 0.10) have ferromagnetic properties.
Time evolution of resistance in response to magnetic field: Evidence of glassy transport in La0.85Sr0.15CoO3
Authors: Samal D. , Kundu R. , Dalai M. K. , Sekhar B. R. , Kumar P. S. Anil 
Published: July 2012

AbstractWe demonstrate the distinct glassy transport phenomena associated with the phase separated and spin‐glass‐like phases of La0.85Sr0.15CoO3, prepared under different heat‐treatment conditions. The low‐temperature annealed (phase‐separated) sample, exhibits a small change in resistance, with evolution of time, as compared to the high‐temperature annealed (spin glass) one. However, the resistance change as a function of time, in both cases, is well described by a stretched exponential fit, signifying the slow dynamics. Moreover, the ultraviolet spectroscopy study evidences a relatively higher density of states in the vicinity of EF for low‐temperature annealed sample and this correctly points to its less semiconducting behavior.
Structuring and destructuring effects along a pathway toward formation of zwitterionic glycine···(H2O)2 complex: many body analysis of clusters and molecular electrostatic potential investigations
Authors: Kulkarni Anant D. , Rai Dhurba , Gejji Shridhar P. , Bartolotti Libero J. , Pathak Rajeev K. 
Published: July 2012

AbstractWe investigate molecular cooperativity in the process of conversion of neutral “canonical” form of glycine···(H2O)2 to its zwitterionic form by an intramolecular proton transfer induced by displacement of the oxygen of the water molecule proximal to the amino group, toward the hydrogen bonded H of the latter. In one of the possible pathways considered here, the carboxyl proton is seen to migrate to the amino group resulting into a stable, energetically locally minimal albeit slightly higher, zwitterionic state. Second‐order Møller‐Plesset perturbation theory (MP2) is used for this study; also, the Density Functional Theory (DFT) that includes popular density functionals, viz. B3LYP, B3PW91, as well as a new‐generation functional M06‐L; in conjunction with the basis set 6‐311++G(2d,2p). The proton transfer concomitantly brings in tangible changes in the molecular electrostatic potential profiles as well as repercussions in the salient infra‐red spectra. It is gratifying that DFT provides a consistently competent description of the transfer process. The proton transfer is examined through a “many‐body interaction‐energy analysis of clusters” scheme whence it is perceived that glycine primarily is neither a structure maker nor a breaker with respect to water···water interactions in the cluster. © 2012 Wiley Periodicals, Inc.
Metabolism profile of timosaponin B‐II in urine after oral administration to rats by ultrahigh‐performance liquid chromatography/quadrupole‐time‐of‐flight mass spectrometry
Authors: Liu Zhirui , Zhu Dongliang , Lv Lei , Li Yueyue , Dong Xing , Zhu Zhenyu , Chai Yifeng 
Published: July 2012

RATIONALETimosaponin B‐II (TB‐II) is one of the major bioactive steroid glycosides isolated from Anemarrhena asphodeloides Bge. (Fam. Liliaceae). It has been regarded as a potential lead compound, which may be further developed into a promising new drug for preventing dementia. To fully understand the action mechanism of TB‐II, it is important to study the metabolism profile of this compound in vivo.METHODSHerein, a rapid and sensitive method based on ultrahigh‐performance liquid chromatography (UHPLC)/quadrupole‐time‐of‐flight mass spectrometry (QTOFMS) was established to comprehensively investigate the metabolism of TB‐II in Sprague–Dawley rat urine following oral administration of a single dose of TB‐II at 500.4 mg·kg–1.RESULTSA total of twelve metabolites were detected and identified by means of comparing molecular mass, retention time and spectral pattern of the analytes with those of the parent drug. A possible metabolic pathway on the biotransformation of TB‐II was also investigated and proposed.CONCLUSIONSOxidation, deglycosylation and E‐ring cleavage were found to be the major metabolic processes of the compound in rat. It is the first report on a mammalian metabolism study of timosaponin, a common member of steroid glycosides, in rat urine. Copyright © 2012 John Wiley & Sons, Ltd.