bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rationalization of the behavior of M2(CH3CS2)4I (M = Ni, Pt) chains at room temperature from periodic density functional theory and ab initio cluster calculations
Authors: Tabookht Zahra , López Xavier , de Graaf Coen , Guihéry Nathalie , Suaud Nicolas , Benamor Nadia 
Published: May 2012

AbstractThe electrical conductivities and plausible charge‐ordering states in the room temperature (r.t.) phase for MMX chains [Ni2(dta)4I]∞ and [Pt2(dta)4I]∞ (dta = CH3CS) have been analyzed with periodic density functional theory (DFT) and correlated ab initio calculations combined with the effective Hamiltonian theory. Periodic DFT calculations show a more delocalized nature of the ground state in [Pt2(dta)4I]∞ compared to [Ni2(dta)4I]∞, which features a rather large energy gap between the occupied and empty bands, and charge polarized dimer units. A larger electrical conductivity for the Pt chain can be expected, especially because the Fermi level lies within a band with contributions from Pt and I orbitals. Electronic structure parameters extracted from ab initio cluster calculations show that the large difference between the observed conductivities at 300 K for Ni and Pt compounds, of 3 orders of magnitude, cannot be explained from the parameters extracted from an embedded M2(dta)4I2 dimer fragment alone. When tetramer fragments are considered, we observe that the interdimer transfer integral (t) between neighboring M2 units connected by an iodine atom at correlated level is comparable in both chains. On the other hand, the energy to transfer an electron from a dimer to the neighboring one (Coulomb repulsion U) is three times larger in the Ni compound with respect to the Pt chain, in line with the poor conductivity of the former. The electronic structure of the M4(dta)8I3 fragment points to an alternate charge‐polarization state for Ni and an average valence state for Pt when the r.t. X‐ray structure is considered. © 2012 Wiley Periodicals, Inc.
Computational investigations on covalent dimerization/oligomerization of polyacenes: Is it relevant to soot formation?
Authors: Koley D. , Arunan E. , Ramakrishnan S. 
Published: May 2012

AbstractWe have postulated a novel pathway that could assist in the nucleation of soot particles through covalent dimerization and oligomerizations of a variety of PAHs. DFT calculations were performed with the objective of obtaining the relative thermal stabilities and formation probabilities of oligomeric species that exploit the facile dimerization that is known to occur in linear oligoacenes. We propose that the presence of small stretches of linear oligoacence (tetracene or longer) in extended PAH, either embedded or tethered, would be adequate for enabling the formation of such dimeric and oligomeric adducts; these could then serve as nuclei for the growth of soot particles. Our studies also reveal the importance of π‐stacking interactions between extended aromatic frameworks in governing the relative stabilities of the oligomeric species that are formed. © 2012 Wiley Periodicals, Inc.
Gill‐arch musculature of the quillback carpiodes cyprinus (cypriniformes: catostomidae) with a comparison to cyprinids
Authors: Grey Ericka A. , Mabee Paula M. 
Published: May 2012

AbstractAlthough the gill‐arch osteology of Cypriniformes has been well studied, comparable works on gill‐arch musculature are scarce. The focus of previous studies has been on Cyprinidae while other families have received little or no attention. Consequently, generalizations for Cypriniformes have been made from the musculature of cyprinid gill‐arches. This study describes the gill‐arch musculature of a catostomid, the quillback Carpiodes cyprinus, and demonstrates that there are striking differences in the overall gill‐arch musculature of catostomids in comparison to cyprinids, especially in the dorsal gill‐arch region. Of the 23 muscles found in the dorsal gill‐arch region of cyprinids, only 13 were present in C. cyprinus. Muscles that are absent include adductores 1–5, levator internus 4, levator ceratobranchialis 5 accessorius, retractor ceratobranchialis 5 externus, retractor ceratobranchialis 5 internus, and the retractor ceratobranchialis 5 transversus. In the ventral gill‐arch region, the rectus communis is absent. The derived scrolling shape of the dorsal gill‐arch skeleton associated with food processing is likely related to the change in musculature. J. Morphol., 2012. © 2012 Wiley Periodicals, Inc.
Performing Culture at the Formosan Aboriginal Culture Village in Taiwan: Exploring Performers' Subjectivities Using Q Method
Authors: Hunter William Cannon 
Published: May 2012

ABSTRACTIn less than two decades, Taiwan indigenous culture has moved from obscurity to a central feature of the national image. Culture performances have become a popular attraction in the country, especially at culture parks. This paper explores how culture performers at the Formosan Aboriginal Culture Village in Taiwan view their work. A demonstration of Q method is used with a P set of 30 respondents and a Q set of 42 statements. Respondents express their subjectivity toward culture performance. It was found that respondents believe that performing indigenous culture is a cultural experience rather than provision of a service commodity. Copyright © 2012 John Wiley & Sons, Ltd.
“Nothing really matters”: Emotional numbing as a link between trauma exposure and callousness in delinquent youth
Authors: Kerig Patricia K. , Bennett Diana C. , Thompson Mamie , Becker Stephen P. 
Published: May 2012

AbstractThis study investigated the interrelations among trauma exposure, emotional numbing, and callous–unemotional traits in a sample of 276 youth (68 girls and 208 boys) recruited from 2 juvenile detention centers. Youth completed interview measures of trauma exposure and betrayal trauma, as well as self‐report measures of emotional numbing and callous–unemotional traits. Results of path analyses using nonparametric bootstrapping procedures indicated findings consistent with the hypothesis that the association between trauma exposure and callous–unemotional traits was mediated by the general numbing of emotions, R2 = .40, and also specifically by numbing of sadness, R2 = .27. In addition, further analyses indicated that numbing of fear, R2 = .18, and sadness, R2 = .26, statistically mediated the relations to callous–unemotional traits only for those traumatic experiences involving betrayal. Gender was not found to moderate these effects.
Evaluating the ability of regional models to predict local avian abundance
Authors: LeBrun Jaymi J. , Thogmartin Wayne E. , Miller James R. 
Published: May 2012

AbstractSpatial modeling over broad scales can potentially direct conservation efforts to areas with high species‐specific abundances. We examined the performance of regional models for predicting bird abundance at spatial scales typically addressed in conservation planning. Specifically, we used point count data on wood thrush (Hylocichla mustelina) and blue‐winged warbler (Vermivora cyanoptera) from 2 time periods (1995–1998 and 2006–2007) to evaluate the ability of regional models derived via Bayesian hierarchical techniques to predict bird abundance. We developed models for each species within Bird Conservation Region (BCR) 23 in the upper midwestern United States at 800‐ha, 8,000‐ha, and approximately 80,000‐ha scales. We obtained count data from the Breeding Bird Survey and land cover data from the National Land Cover Dataset (1992). We evaluated predictions from the best models, as defined by an information‐theoretic criterion, using point count data collected within an ecological subregion of BCR 23 at 131 count stations in the 1990s and again in 2006–2007. Competing (Deviance Information Criteria <5) blue‐winged warbler models accounted for 67% of the variability and suggested positive associations with forest edge and proportion of forest at the 8,000‐ha scale, and negative associations with forest patch area (800 ha) and wetness (800 ha and 80,000 ha). The regional model performed best for blue‐winged warbler predicted abundances from point counts conducted in Iowa during 1995–1996 (rs = 0.57; P = 0.14), the survey period that most closely aligned with the time period of data used for regional model construction. Wood thrush models exhibited positive correlations with point count data for all survey areas and years combined (rs = 0.58, P ≤ 0.001). In comparison, blue‐winged warbler models performed worse as time increased between the point count surveys and vintage of the model building data (rs = 0.03, P = 0.92 for Iowa and rs = 0.13, P = 0.51 for all areas, 2006–2007), likely related to the ephemeral nature of their preferred early successional habitat. Species abundance and sensitivity to changing habitat conditions seems to be an important factor in determining the predictive ability of regional models. Hierarchical models can be a useful tool for concentrating efforts at the scale of management units and should be one of many tools used by land managers, but we caution that the utility of such models may decrease over time for species preferring relatively ephemeral habitats if model inputs are not updated accordingly. © 2012 The Wildlife Society.
Habitat associations of California ground squirrels and Botta's pocket gophers on levees in California
Authors: Ordeñana Miguel A. , Van Vuren Dirk H. , Draper John P. 
Published: May 2012

AbstractVegetation management on levees, especially removal of trees and shrubs, might affect burrowing mammals that are considered threats to levee integrity. We evaluated habitat associations of California ground squirrels (Otospermophilus beecheyi) and Botta's pocket gophers (Thomomys bottae) on levees in the Sacramento Valley to assess the effects of levee vegetation management on these species. Using burrows as an indirect measure of mammal presence, we found that the presence of trees had a negative effect on the occurrence and abundance of ground squirrels on levees, and on the location of their burrowing activities on the levee slope, potentially because visual occlusion caused by tall woody vegetation impedes detection of predators. Similarly, trees had a negative effect on the abundance of pocket gophers on levees and on the location of their burrowing activities on the levee slope, probably because of the effect of tree cover on food availability. The conversion of woodland habitats to grasslands on levees most likely will result in increased occurrence, abundance, or both of ground squirrels and pocket gophers, and thereby increase the potential threat that their burrowing activities pose to levee integrity. © 2012 The Wildlife Society.
Applicability of ring‐on‐disc and pin‐on‐plate test methods for Cu–steel and Al–steel systems for large area conformal contacts
Authors: Pondicherry Kartik S. , Grün Florian , Gódor István , Bertram Rich , Offenbecher Martin 
Published: May 2012

ABSTRACTThis study compares two methods for model scale testing of ferrous/non‐ferrous tribocouples under large area conformal contact condition, the kind existing in engine components such as journal bearings. Results show that the ring‐on‐disc method is better suited to visualise the performance of such tribosystems compared with the pin‐on‐plate method. The former offers greater sensitivity to minor changes in coefficient of friction and contact potential and is able to determine the thermal stability of the tribosystem under given conditions. Post‐test surface characterisation revealed protective phosphorus‐rich tribofilms on the surface of the steel counterparts from both test methods. Copyright © 2012 John Wiley & Sons, Ltd.
Fluorescence Micropatterning by the Photo‐Anilide Rearrangement of Polymer Bearing Anilide Groups
Authors: Chae Kyu Ho , Baek Sun Jung 
Published: May 2012

AbstractA fluorescent micropattern in a thin polymer film is fabricated via a photo‐anilide rearrangement of anilide groups in the polymer. Polymer bearing anilide groups are prepared by polymerization of N‐phenyl methacrylamide (PMA) and methyl methacrylate. The photo‐anilide rearrangement of the prepared polymer and the reaction of the produced amino groups with fluorescamine, are studied by using UV and IR absorption spectroscopy. The fluorescence spectrum of the fluorescamine‐treated irradiated polymer film shows a strong fluorescence in the range of ≈420–620 nm with a fluorescence maximum at 496 nm. The patterns exhibited very distinct fluorescence images in the colors of dark blue, sky blue, green, yellow, and red depending on the observed wavelength ranges.
Size‐Tunable Polymeric Nanoreactors for One‐Pot Synthesis and Encapsulation of Quantum Dots
Authors: Qian Guannan , Zhu Benchuan , Wang Youfu , Deng Sheng , Hu Aiguo 
Published: May 2012

AbstractHydrophilic polymeric nanoparticles are synthesized through a Bergman cyclization‐ mediated intramolecular chain collapse of structurally well‐defined linear polymers, and then used as size‐tunable nanoreactors to fabricate and encapsulate quantum dots in a one‐pot reaction. Crystalline quantum dots are formed in all of these nanoreactors and visualized by transmission electron microscopy. Smaller nanoreactors produce one quantum dot each while larger nanoreactors form a number, resulting in fluorescence quenching. By controlling the molecular weight of the linear polymer precursor, a variable number of nanocrystals are fabricated and assembled in a single nanoreactor.
Liraglutide withdrawal rates: ‘real world’ practice
Authors: Balasanthiran A , Munro N , Watters K , Poots AJ , Morganstein D , Feher MD 
Published: May 2012

AbstractImportant side effects and potential clinical hazards have emerged from long‐term follow up in some drug classes used in type 2 diabetes treatment. Systematic phase 4 post‐marketing data in early use of newer diabetes drugs may have a role in informing drug choice in practice and assist in pharmacoeconomic assessments of these drug choices.We carried out a comparison of the prevalence of drug withdrawals derived from both liraglutide registration trial data, and a systematic, prospective case‐note review of all new liraglutide prescriptions (n=176) from a specialist diabetes clinic over the first 12 months of drug introduction.Trial data used for the marketing authorisation application for liraglutide reported 7.0% withdrawal due to adverse events. Equal numbers of patients experienced mild, moderate and severe side effects. By contrast, data derived from a ‘real world’ clinical group describe 14.8% withdrawal due to adverse events, with withdrawal typically occurring early, by three months. Adverse events were more frequently responsible for treatment withdrawal at lower, compared to higher, doses of liraglutide therapy.Systematic observations of withdrawals in early use of new drugs in current clinical practice are higher than reported in registration trial data. These data highlight that post‐marketing surveillance should inform guideline recommendations and pharmacoeconomic evaluations. Copyright © 2012 John Wiley & Sons.
Biodegradable aromatic copolyesters made from bicyclic acetalized galactaric acid
Authors: Lavilla C. , Alla A. , Martínez de Ilarduya A. , Benito E. , García‐Martín M.G. , Galbis J.A. , Muñoz‐Guerra S. 
Published: May 2012

AbstractRandom poly(hexamethylene terephthalate‐co‐galactarate)s and poly(dodecamethylene terephthalate‐co‐galactarate)s copolyesters covering the whole range of compositions were obtained with weight‐average molecular weights of ∼30,000–50,000 g mol−1 by melt polycondensation. They were thermally stable above 300 °C, and displayed Tg in the +20 to −20 °C range with values steadily decreasing with the content in galactarate units. All the copolyesters were semicrystalline with Tm between 50 and 150 °C and those made from dodecanediol were able to crystallize from the melt at a crystallization rate depending on composition. Copolyesters containing up to 50% of galactaric units retained the crystal structure of their respective polyterephthalate homopolyesters, whereas they adopted the structure of the respective polygalactarates when the content in Galx units reached 70%. Stress‐strain essays revealed decay in the mechanical parameters as the aromatic units were replaced by Galx. Incubation in aqueous buffer revealed that hydrolysis of the polyesters were largely enhanced by copolymerization and evidenced the capacity of the Galx unit for making aromatic polyesters susceptible to biodegradation. A detailed NMR analysis complemented by SEM observations indicated that hydrolysis took place by preferred splitting of galactarate ester bonds with releasing of alkanediol and Galx‐diacid. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Synthesis of novel oligoester‐block‐polyacrylate‐block‐oligoester ABA triblock copolymers by coupling methods
Authors: Liénafa Livie , Monge Sophie , Robin Jean‐Jacques 
Published: May 2012

AbstractAn original approach based on coupling methodology was used to prepare novel well‐defined ABA triblock copolymers, made of polyester‐type chain ends (A) associated with a polyacrylate midblock (B). Poly(ethylene terephthalate)‐block‐poly(lauryl acrylate)‐block‐poly(ethylene terephthalate) (PET‐b‐PLAc‐b‐PET) copolymers were achieved from poly(ethylene terephthalate)‐b‐poly(lauryl acrylate) (PET‐b‐PLAc) diblock ones. The first step consisted in the synthesis of diblock copolymers by atom transfer radical polymerization of lauryl acrylate starting from PET segment as a macroinitiator. In the second step, the coupling of diblock copolymers was achieved using four different methods, which were evaluated and compared: atom transfer radical coupling, “click” chemistry using the Huisgen's reaction, and coupling via a dithiol reagent or a diisocyanate molecule. Coupling using the Huisgen's reaction or a diisocyanate spacer proved to be the most efficient techniques. Even if these methods showed limitation and were only adapted for copolymers with low molecular weights, we managed to successfully prepare ABA triblock copolymers involving a polyester segment as end blocks and a polyacrylate moiety as midblock. To our knowledge, such kind of chemical structure has never been reported before and would be useful, possibly affording physical networks leading to rheological modification, for instance. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Surface nanostructuring of kevlar fibers by atmospheric pressure plasma‐induced graft polymerization for multifunctional protective clothing
Authors: Widodo Mohamad , El‐Shafei Ahmed , Hauser Peter J. 
Published: May 2012

AbstractAtmospheric plasma‐induced graft polymerization was employed successfully to generate free radical on the surface of Kevlar® (poly‐(p‐phenylene terephthalamide or PPTA), and to initiate and control graft polymerization of cationic antimicrobial precursors diallyldimethylammonium chloride (DADMAC) or 3‐(trimethoxysilyl)propyl‐dimethyloctadecyl ammonium chloride (TMS) onto the fabric surface, which eliminates the need for separate processes that may involve thermal energy or UV irradiation. It was demonstrated that when the radiofrequency of the plasma power was 400 W, the radical density generated on the surface was 1015 to 1016 radicals cm−2, which were enough to generate a poly‐DADMAC or poly‐TMS with surface charge of at least 2 × 1017 N+/cm2, which is the minimum threshold for an effective cationic biocidal surface. In both cases, the grafted polymers were characterized and confirmed using SEM, FTIR, and XPS. The antimicrobial activity was measured using the AATCC Test Method 100, which showed that at least 3‐log reduction of bacteria colonies was achieved in the case of grafted poly‐DADMAC or grafted poly‐TMS on Kevlar®. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Carrier dynamics and efficiency droop in AlGaN epilayers with different Al content
Authors: Tamulaitis Gintautas , Mickevičius Jūras , Dobrovolskas Darius , Kuokštis Edmundas , Shur Michael S. , Shatalov Max , Yang Jinwei , Gaska Remis 
Published: May 2012

AbstractCarrier dynamics and emission efficiency droop in AlGaN epilayers containing different Al content were studied under pulsed (30 ps) and quasi‐steady‐state photoexcitation. Samples with Al content ranging from 17% to 50% but having similar carrier lifetimes (50‐80 ps) were selected for the study. Considerable heating of nonequilibrium carriers at room temperature was observed. Carrier redistribution down to deeper localized states is demonstrated. It is shown that the temperature decay is faster than the decay of localized carriers, which determine the photoluminescence decay kinetics at later stages of the decay. The efficiency droop onsets at lower excitation power densities in the samples with higher Al content presumably having higher density of nonradiative recombination centers and higher density of localized states. The results are in favour of the assumption that the droop in these epilayers is caused by saturation of the localized states and hopping of less localized carriers to the centers of nonradiative recombination. The effect might be enhanced by carrier heating (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electronic structure and optical anisotropy of InGaAs quantum rods studied by photoreflectance and photoluminescence
Authors: Nedzinskas Ramūnas , Čechavičius Bronislovas , Česnauskas Audrius , Kavaliauskas Julius , Karpus Vytautas , Valušis Gintaras , Li Lianhe , Khanna Suraj P. , Linfield Edmund H. 
Published: May 2012

AbstractSelf‐assembling nanostructures comprising InGaAs quantum rods (QRs) immersed into 2‐dimensional InGaAs layer (QW) were examined by photoreflectance (PR) and photoluminescence (PL) spectroscopy techniques. Spectral features associated with interband op‐ tical transitions occurring in the QR and the surrounding QW regions have been identified. The polarized PR and PL studies revealed a high in‐plane optical anisotropy of ≈60% for QR‐related optical transitions.We have clearly observed that both the QR‐ and the QW‐related transition energies, and PL intensities are sensitive to the As source (As2 or As4) used in molecular beam epitaxy growth of the nanostructures. The changes in optical response are mainly attributed to carrier confinement effects caused by variation in indium content within the QR and QW regions. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Resonant optical reflection by periodic systems of the GaAs/AlGaAs quantum well excitons
Authors: Chaldyshev V. V. , Kundelev E. V. , Chen Yuechao , Poddubny A. N. , Vasil'ev A. P. , Liu Zhiheng 
Published: May 2012

AbstractA periodic multiple quantum well GaAs/AlGaAs structure was designed, grown and characterized in order to reveal resonant features in optical spectra when the Bragg resonance was tuned to the first or second quantum state of the heavy‐hole exciton‐polaritons in the quantum wells. We observed a super‐radiant optical mode formed by the quantum well excitons under double resonance condition, i.e. when the exciton‐polariton and Bragg resonances are met at the same frequency. It is manifested in a strong and wide reflection and electroreflection band (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Repulsive Casimir force between silicon dioxide and superconductor
Authors: Phan Anh D. , Viet N. A. 
Published: May 2012

AbstractWe present a detailed investigation of the Casimir interaction between the superconductor Bi2Sr2CaCu2O8+δ (BSCCO) and silicon dioxide with bromobenzene present in between. We found that the dispersion force is repulsive and the magnitude of the force can be changed by varying the thickness of the object and the temperature. The repulsive force would provide a method to deal with stiction problems and provide much significant from the practical point of view. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)