bluuebunny/crossref_metadata_2025_split huggingface dataset:
Three‐dimensional multislice spiral computed tomographic angiography: A potentially useful tool for safer free tissue transfer to complicated regions
Authors: Demirtas Yener , Cifci Mehmet , Kelahmetoglu Osman , Demir Ahmet , Danaci Murat 
Published: April 2009

AbstractThree‐dimensional multislice spiral computed tomographic angiography (3D‐MSCTA) is a minimally invasive method of vascular mapping. The aim of this study was to evaluate the clinical usefulness of this imaging technique in delineating the recipient vessels for safer free tissue transfer to complicated regions. 3D‐MSCTA was performed preoperatively in 26 patients scheduled for free tissue transfer, in whom the availability of the recipient vessels were considered to be uncertain, and 23 of these were operated on. Radiographic and operative findings regarding the availability of the recipient vessels for anastomosis were correlated in 21 of these 23 patients. 3D‐MSCTA yielded two false‐positive results; anastomosis was not possible because of widespread atherosclerotic plaques and poor flow observed in the recipient arteries despite the good caliber observed in 3D‐MSCTA images. 3D‐MSCTA provides a noninvasive means of preoperatively assessing recipient site vessels for anatomic variations and suitability before free tissue transfer and enables the surgeon to establish an appropriate treatment plan. But it is not 100% reliable yet and the possibility of false‐positive results should be kept in mind, especially inthe patients with peripheral vascular disease. 3D‐MSCTA has the potential to replace digital subtraction angiography for planning of microvascular reconstructions and newer devices with higher resolutions will probably increase the reliability of this technique. © 2009 Wiley‐Liss, Inc. Microsurgery, 2009.
Improved applicability of DOSY experiments by high resolution probes combined with gradient amplifiers of diffusion units
Authors: Zhang Hongxia , Kerssebaum Rainer , Gschwind Ruth M. 
Published: April 2009

AbstractShort relaxation times and small diffusion coefficients often impede reliable diffusion experiments due to insufficient signal to noise ratios, especially in low temperature studies, where in the case of small diffusion coefficients in combination with very short T2 times and substantial convection, double‐stimulated‐echo experiments are required as last resort of convection‐compensating DOSY pulse sequences. Therefore, the combination of a strong gradient amplifier of a diffusion unit with Z‐gradient high resolution probes is tested for low temperature applications to combine the advantages of high 1H resolution, flexible temperature, and multinuclear applications with short gradient durations and diffusion delay. The experimental spectra on phosphoramidite ligands and phosphoramidite‐copper complexes show that signal to noise improvements up to 176% were achieved despite longer eddy current delays and increased noise levels. Calculational estimations of the enhancement factors predict special benefits for systems with short transversal relaxation times and small diffusion coefficients and promise even higher enhancement factors for noise level optimized combinations. In addition, an easy way is presented to find fast and effectively relaxation optimized DOSY parameters for the convection‐compensated double‐stimulated‐echo pulse sequence of Jerschow and Müller. Copyright © 2009 John Wiley & Sons, Ltd.
Theoretical investigation on multinuclear NMR chemical shifts of some tris(trifluoromethyl)boron complexes
Authors: Zhang Jun , Cai Shuhui , Chen Zhong 
Published: April 2009

AbstractTris(trifluoromethyl)boron complexes have unusual properties and may find applications in many fields of chemistry, biology, and physics. To gain insight into their NMR properties, the isotropic 11B, 13C, and 19F NMR chemical shifts of a series of tris(trifluoromethyl)boron complexes were systematically studied using the gauge‐included atomic orbitals (GIAO) method at the levels of B3LYP/6‐31 + G(d,p)//B3LYP/6‐31G* and B3LYP/6‐311 + G(d,p)//B3LYP/6‐311 + G(d,p). Solvent effects were taken into account by polarizable continuum models (PCM). The calculated results were compared with the experimental values. The reason that the structurally inequivalent fluorine atoms in a specific species give a same chemical shift in experimental measurements is attributed to the fast rotation of CF3 group around the BC(F3) bond because of the low energy barrier. The calculated 11B, 13C(F3), and 19F chemical shifts are in good agreement with the experimental measurements, while the deviations of calculated 13C(X, X = O, N) chemical shifts are slightly large. For the latter, the average absolute deviations of the results from B3LYP/6‐311 + G(d,p)//B3LYP/6‐311 + G(d,p) are smaller than those from B3LYP/6‐31 + G(d,p)//B3LYP/6‐31G*, and the inclusion of PCM reduces the deviation values. The calculated 19F and 11B chemical shieldings of (CF3)3BCO are greatly dependent on the optimized structures, while the influence of structural parameters on the calculated 13C chemical shieldings is minor. Copyright © 2009 John Wiley & Sons, Ltd.
Recovery of equilibrium on star patches using a partition of unity technique
Authors: Moitinho de Almeida J. P. , Maunder E. A. W. 
Published: April 2009

AbstractA technique for recovering equilibrated element stresses is developed for finite element models of structural mechanics problems. The data for the method consist of the prescribed loading and the stress and displacement fields resulting from a conventional compatible finite element model. Local problems are defined for each star of elements, via the introduction of fictitious body forces and strains. These problems can be solved independently for equilibrium in a process that can be easily parallelized. The quality of the solutions is assessed, for two‐dimensional linear elastic problems, by using them to compute bounds of the error of the finite element solutions, in terms of both global and local quantities of interest. Copyright © 2009 John Wiley & Sons, Ltd.
Altered expression of MUTYH and an increase in 8‐hydroxydeoxyguanosine are early events in ulcerative colitis‐associated carcinogenesis
Authors: Gushima Masaki , Hirahashi Minako , Matsumoto Takayuki , Fujita Kouhei , Fujisawa Ritsuko , Mizumoto Kazuhiro , Nakabeppu Yusaku , Iida Mitsuo , Yao Takashi , Tsuneyoshi Masazumi 
Published: April 2009

Abstract8‐Hydroxy‐guanine (8‐OH‐G) mismatches readily with adenine residues, leading to a G : C to T : A transversion mutation. The human mutY homologue (MUTYH) excises adenine misincorporated opposite 8‐OH‐G during replication and suppresses mutations caused by reactive oxygen species. We defined the expression of 8‐hydroxydeoxyguanosine (8‐OHdG) and MUTYH in ulcerative colitis (UC)‐associated neoplasia by immunohistochemistry and compared this with expression in UC patients without neoplasia and patients unaffected by UC. We also performed mutation analyses for MUTYH and K‐ras. 8‐OHdG was expressed more intensely in the mucosa of UC‐associated neoplasia and UC without neoplasm than in the mucosa unaffected by UC. Immunohistochemistry with two different types of MUTYH antibody showed that UC‐associated neoplasia and UC without neoplasia exhibited strong cytoplasmic expression and attenuated nuclear expression of MUTYH when compared with patients unaffected by UC. No pathological MUTYH mutations were detected in any of the UC‐associated neoplasia cases. However, K‐ras mutation was detected in two cases, one of which showed G : C to T : A transversion mutation and attenuated nuclear staining of MUTYH. In conclusion, inflamed mucosa of UC is exposed to oxidative damage. An increase in cytoplasmic MUTYH, rather than its mutation, may contribute to the promotion of carcinogenesis in UC. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Synthetic popularity reflects chemical reactivity
Authors: Kowalczyk Bartlomiej , Bishop Kyle J. M. , Smoukov Stoyan K. , Grzybowski Bartosz A. 
Published: April 2009

AbstractLarge and diverse databases of chemical reactions contain statistically significant information about the propensities of molecules to undergo specific chemical transformations. It is shown that this information can be quantified to reflect reaction thermodynamics/kinetics and can be used to construct primitive (yet accurate) reactivity indices from the counts of reported reactions involving molecules/molecular positions of interest. These indices correlate with frontier orbital (FO) populations or Hammettσandρparameters for a range of reactions involving aromatic substrates. These findings suggest that large chemical databases are not only a historical repository of chemical knowledge but also tools with which one can make useful chemical predictions. Copyright © 2009 John Wiley & Sons, Ltd.
A DFT/TD‐DFT study for the ground and excited states of peramine and some pyrrolopyrazinone compounds
Authors: Łapiński Andrzej , Dubis Alina T. 
Published: April 2009

AbstractPeramine, a heterocyclic natural molecule, reveals two main, different in nature, electronic absorption bands. Theoretical calculations at the TD‐B3LYP/6–311++G(d,p) level of theory show that the electronic excitations are connected predominantly with π → π* and charge‐transfer (CT) transitions. Excitation of electrons from the pyrrolopyrazinone ring to the side chain plays a role in creating the CT transition. The character and energy of the first 30 singlet–singlet electronic transitions have also been investigated for the most stable conformation of peramine. Copyright © 2009 John Wiley & Sons, Ltd.
Fluticasone propionate/salmeterol and exercise‐induced asthma in children with persistent asthma
Authors: Pearlman David , Qaqundah Paul , Matz Jonathan , Yancey Steven W. , Stempel David A. , Ortega Hector G. 
Published: April 2009

AbstractRationaleExercise is a common trigger in children with persistent asthma and inhaled corticosteroids have been shown to effectively treat clinical manifestations of persistent asthma, including protection from decrements in lung function caused by exercise. The goal of this study was to evaluate the effectiveness of fluticasone propionate/salmeterol 100/50 mcg compared with fluticasone propionate 100 mcg for the prevention of airflow limitation triggered by standardized exercise challenge in pediatric and adolescent patients with persistent asthma.MethodsMulticenter, randomized, double‐blind, parallel group trial of 248 subjects with persistent asthma (age 4–17 years) randomized to receive fluticasone propionate/salmeterol (100/50 mcg twice daily) or fluticasone propionate alone (100 mcg twice daily) via Diskus for 4 weeks. Exercise challenge tests were performed during screening and approximately 8 hr after administration of the blinded study medication on Treatment Day 28.ResultsAfter 4 weeks of therapy both treatments provided protection following exercise challenge. The protection estimated by the maximal fall in FEV1 was significantly better for fluticasone propionate/salmeterol (9.5 ± 0.8% [mean ± SE]) compared with fluticasone propionate alone (12.7 ± 1.1%, P = 0.021). Statistically significant differences were not observed for asthma rescue‐free days and asthma symptom‐free days.ConclusionChronic dosing with fluticasone propionate/salmeterol in a single device provides superior protection compared with an inhaled corticosteroid alone in protecting against exercise‐induced asthma in children with persistent asthma. Pediatr Pulmonol. 2009; 44:429–435. © 2009 Wiley‐Liss, Inc.
Predicting changes in clinical status of young asthmatics: Clinical scores or objective parameters?
Authors: Leung Ting F. , Ko Fanny W.S. , Wong Gary W.K. , Li Chung Y. , Yung Edmund , Hui David S.C. , Lai Christopher K.W. 
Published: April 2009

AbstractPreventing asthma exacerbation is an important goal of asthma management. The existing clinical tools are not good in predicting asthma exacerbations in young children. Childhood Asthma Control Test (C‐ACT) was recently published to be a simple tool for assessing disease control in young children. This study investigated C‐ACT and other disease‐related factors for indicating longitudinal changes in asthma status and predicting asthma exacerbations. During the same clinic visit, asthma patients aged 4–11 years completed the Chinese version of C‐ACT and underwent exhaled nitric oxide and spirometric measurements. Blinded to these results, the same investigator assigned Disease Severity Score (DSS) and rated asthma control according to Global Initiative for Asthma. Asthma exacerbations during the next 6 months were recorded. Ninety‐seven patients were recruited, with their mean (standard deviation [SD]) age being 9.2 (2.0) years. Thirty‐six (37.1%) patients had uncontrolled asthma at baseline. C‐ACT, DSS, and FEV1 differed among patients with different control status (P < 0.001 for C‐ACT and DSS; P = 0.028 for FEV1). Thirty‐two patients had asthma exacerbations during the 6‐month follow‐up. Changes in patients' C‐ACT scores correlated with changes in asthma control status, DSS, and FEV1 (P = 0.019, 0.034, and 0.020, respectively). C‐ACT score was lower among patients with asthma exacerbations (mean [SD]: 22.9 [4.2] vs. 24.5 [2.1]; P = 0.015). Logistic regression confirmed that the occurrence of asthma exacerbations was associated only with baseline C‐ACT (B = −0.203, P = 0.042). In conclusion, C‐ACT is better than DSS and objective parameters in reflecting changes in asthma status and predicting asthma exacerbations in young children. Pediatr Pulmonol. 2009; 44:442–449. © 2009 Wiley‐Liss, Inc.
UV properties of 𝒩 = 8 supergravity
Authors: Kallosh R. 
Published: April 2009

AbstractWe discuss here the recent developments in 𝒩 = 8 supergravity. In particular, we propose to use the light‐cone superspace with an unconstrained chiral scalar superfield for the studies of the UV structure of the perturbative 𝒩 = 8 supergravity. For this purpose we construct the generating functional for the light‐cone momentum space superfield amplitudes. We prove an 𝒩 = 8 equivalence theorem for the light‐cone and covariant on‐shell amplitudes. We point out an interesting relation between our light‐cone formalism and Nair' s construction and supertwistors. We also point out the importance of the non‐linearly realized E(7,7), symmetry for these studies and argue that this symmetry may be anomaly‐free.
Gravity as the square of Yang‐Mills: implications for 𝒩 = 8 supergravity
Authors: Ananth S. 
Published: April 2009

AbstractThe pure gravity Lagrangian can be written as the “square” of the pure Yang‐Mills Lagrangian to second order in coupling constants. This paper uses this form of the gravity Lagrangian as a starting point to arrive at a compact light‐cone superspace Lagrangian for 𝒩 = 8 supergravity to order κ2.
Low thermal resistance, high‐speed 980 nm asymmetric intracavity‐contacted oxide‐aperture VCSELs
Authors: Song Y. M. , Chang K. S. , Na B. H. , Yu J. S. , Lee Y. T. 
Published: April 2009

AbstractWe demonstrated high‐speed characteristics of an oxide‐aperture vertical‐cavity surface‐emitting laser (VCSEL) with intracavity structures for both p‐ and n‐contacts, based on InGaAs/GaAs multiple quantum wells operating at λ ∼ 980 nm, indicating a low thermal resistance (Rth). The asymmetric current injection scheme is employed for reducing current crowding around the rim of the oxide aperture. A high aluminium content undoped Al0.88Ga0.12As and GaAs distributed Bragg reflector (DBR) mirror is used for efficient heat dissipation. The VCSEL with a 7 μm oxide aperture exhibited an output power of 2.5 mW and a threshold current of 0.8 mA with a slope efficiency of 0.39 mW/mA at 20 °C under continuous‐wave operation and it still worked with 1.3 mW at 90 °C. The temperature tuning coefficient of 0.081 nm/°C and dissipated electrical power tuning coefficient of 0.104 nm/mW were observed, leading to a low Rth of 1.28 °C/mW. A high modulation bandwidth up to 13 GHz with a modulation current efficiency factor of 6.1 GHz/mA1/2 was achieved. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ray‐tracing study of Bragg diffraction‐assisted light extraction efficiency of GaN‐based light‐emitting diodes with vertical sidewalls
Authors: Liu Wen‐de , Gan Zi‐zhao 
Published: April 2009

AbstractRay‐tracing method is used to investigate the light extraction efficiency (LEE) of Bragg diffraction‐assisted GaN‐based light‐emitting diodes (LED's) with vertical sidewalls. The ray tracing is based on the analytical formulae of the LEE in the incoherent regime for LED model with infinite lateral size. It is shown that without considering the sidewalls, the change of the LEE with the absorption or backside reflectivity is too small and thus not reasonable. And the enhancement with respect to the unpatterned case could be overestimated by ignoring the finite‐size effect. Numerical calculations show that the enhancement of the LEE due to the sidewalls when compared to the infinite model could be up to 10% or even higher. Besides, the extracted energy from the sidewalls decreases due to the increased extraction from the PhC when compared to the unpatterned LED. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Strain effects and phonon–plasmon coupled modes in Si‐doped AlN
Authors: Gómez‐Gómez M. , Cros A. , Hermann M. , Stutzmann M. , Eickhoff M. 
Published: April 2009

AbstractThe E2h and A1(LO) phonon modes of AlN films grown on sapphire are analyzed by Raman scattering as a function of silicon doping for concentrations covering from 5.5 × 1019 cm–3 to 5.2 × 1021 cm–3. For high doping levels the appearance of a mode around 520 cm–1 indicates the precipitation of crystalline silicon in the samples and its inhomogeneous incorporation to the AlN layer. The frequency of this mode shifts to lower energies with doping, indicating that the silicon crystals are embedded in the AlN lattice and under tensile strain. On the other hand, the AlN phonon modes are blue‐shifted due to the compressive strain as a result of the silicon incorporation. This strain is partially relieved for very high doping levels. The coupling of the polar A1(LO) mode of the AlN films with the electronic cloud (phonon–plasmon coupling) is analyzed for electron concentrations up to 4 × 1017 cm–3. A 2 cm–1 blue shift of the phonon frequencies is observed for the highest electron concentrations. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
UV emission on a Si substrate: Optical and structural properties of γ‐CuCl on Si grown using liquid phase epitaxy techniques
Authors: Cowley A. , Foy B. , Danilieuk D. , McNally P. J. , Bradley A. L. , McGlynn E. , Danilewsky A. N. 
Published: April 2009

AbstractConsiderable research is being carried out in the area of wide band gap semiconductor materials for light emission in the 300–400 nm spectral range. Current materials being used for such devices are typically based on II–VI and III‐nitride compounds and variants thereof. However, one of the major obstacles to the successful fabrication of III‐N devices is lattice mismatch‐induced high dislocation densities for epitaxially grown layers on non‐native substrates. γ‐CuCl is a direct bandgap material and an ionic wide bandgap I–VII semiconductor with a room temperature free exciton binding energy of ∼190 meV (compared to ∼25 meV and ∼60 meV for GaN and ZnO, respectively) and has a band gap of 3.4 eV (λ ∼ 366 nm). The lattice constant of γ‐CuCl (0.541 nm) is closely matched to that of Si (0.543 nm). This could, in principle, lead to the development of optoelectronic systems based on CuCl grown on Si. Research towards this end has successfully yielded polycrystalline γ‐CuCl on Si(100) and Si(111) using vacuum‐based deposition techniques [1]. We report on developments towards achieving single crystal growth of CuCl from solution via Liquid Phase Epitaxy (LPE) based techniques. Work is being carried out using alkali halide flux compounds to depress the liquidus temperature of the CuCl below its solid phase wurtzite‐zincblende transition temperature (407 °C [2]) for solution based epitaxy on Si substrates. Initial results show that the resulting KCl flux‐driven deposition of CuCl onto the Si substrate has yielded superior photoluminescence (PL) and X‐ray excited optical luminescence (XEOL) behavior relative to comparitively observed spectra for GaN or polycrystalline CuCl. This enhancement is believed to be caused by an interaction between the KCl and CuCl material subsequent to the deposition process, perhaps involving a reduction in Cl vacancy distributions in CuCl. This paper presents a detailed discussion of a CuCl LPE growth system as well as the characterization of deposited materials using X‐ray diffraction (XRD), room temperature and low temperature PL, and XEOL. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Microscopic description of strain‐reducing chemical bonding self‐organizations in non‐crystalline alloys
Authors: Lucovsky Gerald , Phillips James C. 
Published: April 2009

AbstractAlloy compositions for a first transition (1) into, and a second transition (2) out of intermediate phases (IPs) have been identified (i) by Boolchand and co‐workers in bulk glasses, primarily by low values for the change in enthalpy, ΔHnr, for non‐reversible heat flow at the glass transition temperature, and (ii) by Lucovsky and coworkers in deposited thin film by combining spectrographic and electrical studies. This paper emphasizes chemical bonding self‐organizations that minimize macroscopic strain within IP windows, identifying necessary and sufficient conditions for IP windows to open, and to close. Percolation theory, competitive and synergistic double percolation, provide a framework for determining alloy compositions for the first and second transitions of IP windows in bulk glasses and thin films as well. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Controlled chemical phase separation in binary and ternary composites: A pathway to isotropic optical and electrical behavior for device applications
Authors: Lucovsky Gerald 
Published: April 2009

AbstractThere are many applications for nanocrystalline thin films in optical devices that require isotropic optical properties. A novel way to obtain these isotropic properties for the index of refraction and/or optical absorption constant, etc., and at the same time to minimize microscopic strain is presented in this article. This approach is based on strain reduction mechanisms that occur in the intermediate phases, IPs, of non‐crystalline glasses and thin films. In these compositional regimes, either site percolation, or volume percolation, each above an applicable critical value, provides a quantitative understanding of the microscopic bonding arrangements associated with strain‐reducing chemical bonding self‐organizations. A similar framework, presented for the first time in this article, develops a microscopic understanding of macroscopic strain reduction in several different phase‐separated composites. This understanding has emerged from focussed research on qualitatively different hetero‐structure device structure constituents, e.g.; (i) high‐k replacement dielectrics for SiO2 in field effect transistors gate stacks for advanced semiconductor devices, and (ii) active and passive thin films for optically switched memory cells. In each instance strain reduction and its intrinsic relationship to low densities of defects and defect precursors has provided a driving force in the identification of a narrow range of compositions that satisfy technological needs. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)