bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nonintrusive coupling of 3D and 2D laminated composite models based on finite element 3D recovery
Authors: Guguin Guillaume , Allix Olivier , Gosselet Pierre , Guinard Stéphane 
Published: January 2014

SUMMARYIn order to simulate the mechanical behavior of large structures assembled from thin composite panels, we propose a coupling technique, which substitutes local 3D models for the global plate model in the critical zones where plate modeling is inadequate. The transition from 3D to 2D is based on stress and displacement distributions associated with Saint‐Venant problems, which are precalculated automatically for a simple 3D cell. The hybrid plate/3D model is obtained after convergence of a series of iterations between a global plate model of the structure and localized 3D models of the critical zones. This technique is nonintrusive because the global calculations can be carried out using commercial software. Evaluation tests show that convergence is fast and that the resulting hybrid model is very close to a full 3D model. Copyright © 2014 John Wiley & Sons, Ltd.
Hybrid displacement function element method: a simple hybrid‐Trefftz stress element method for analysis of Mindlin–Reissner plate
Authors: Cen Song , Shang Yan , Li Chen‐Feng , Li Hong‐Guang 
Published: January 2014

SUMMARYIn order to develop robust finite element models for analysis of thin and moderately thick plates, a simple hybrid displacement function element method is presented. First, the variational functional of complementary energy for Mindlin–Reissner plates is modified to be expressed by a displacement function F, which can be used to derive displacement components satisfying all governing equations. Second, the assumed element resultant force fields, which can satisfy all related governing equations, are derived from the fundamental analytical solutions of F. Third, the displacements and shear strains along each element boundary are determined by the locking‐free formulae based on the Timoshenko's beam theory. Finally, by applying the principle of minimum complementary energy, the element stiffness matrix related to the conventional nodal displacement DOFs is obtained. Because the trial functions of the domain stress approximations a priori satisfy governing equations, this method is consistent with the hybrid‐Trefftz stress element method. As an example, a 4‐node, 12‐DOF quadrilateral plate bending element, HDF‐P4‐11 β, is formulated. Numerical benchmark examples have proved that the new model possesses excellent precision. It is also a shape‐free element that performs very well even when a severely distorted mesh containing concave quadrilateral and degenerated triangular elements is employed. Copyright © 2014 John Wiley & Sons, Ltd.
Estimation of fixed charge density and diffusivity profiles in cartilage using contrast enhanced computer tomography
Authors: Huttunen J.M.J. , Kokkonen H.T. , Jurvelin J.S. , Töyräs J. , Kaipio J.P. 
Published: January 2014

SUMMARYContrast enhanced computer tomography (CT) imaging of articular cartilage has been proposed for diagnostics of cartilage degeneration, that is, osteoarthritis. Previous studies also indicate that acute cartilage damage can be detected by measuring diffusion of contrast agent into cartilage using CT. However, currently, there is no reliable method to measure spatial diffusion rates within cartilage tissue, and only average bulk values have been reported. In this paper, we develop a method to determine depthwise diffusivity of contrast agents in cartilage tissue using contrast enhanced CT. The triphasic mechano‐electrochemical theory of cartilage is modified to include diffusion of contrast agents. By applying statistical inversion theory and Bayesian approximation error approach, the method allows us to estimate a fixed charge density distribution in the cartilage tissue, an important determinant for mechanical competence of articular cartilage. The method is tested by using a one‐dimensional simulation study. Preliminary tests with experimental data on diffusion of anionic iodine contrast agent in bovine articular cartilage indicate that the method can provide realistic estimates for depth dependent fixed charge density. Thereby, the present study can improve our understanding on the feasibility of contrast enhanced CT for cartilage diagnostics. Copyright © 2014 John Wiley & Sons, Ltd.
Bifurcation indicator based on meshless and asymptotic numerical methods for nonlinear poisson problems
Authors: Tri Abdeljalil , Zahrouni Hamid , Potier‐Ferry Michel 
Published: January 2014

AbstractWe propose in this work new algorithms associating asymptotic numerical method and meshless discretization (MFS‐MPS: Method of fundamental solutions‐Method of particular solutions) to compute branch solutions of nonlinear Poisson problems. To detect singular points on these branches, geometrical indicator, Padé approximants, and analytical bifurcation indicator are proposed. Numerical applications show the robustness and the effectiveness of the proposed algorithms. © 2014 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 30: 978–993, 2014
Numerical analysis of two partitioned methods for uncoupling evolutionary MHD flows
Authors: Layton W. , Tran H. , Trenchea C. 
Published: January 2014

AbstractMagnetohydrodynamics (MHD) studies the dynamics of electrically conducting fluids, involving Navier–Stokes (NSE) equations in fluid dynamics and Maxwell equations in eletromagnetism. The physical processes of fluid flows and electricity and magnetism are quite different and numerical simulations of each subprocess can require different meshes, time steps, and methods. In most terrestrial applications, MHD flows occur at low‐magnetic Reynold numbers. We introduce two partitioned methods to solve evolutionary MHD equations in such cases. The methods we study allow us at each time step to call NSE and Maxwell codes separately, each possibly optimized for the subproblem's respective physics. Complete error analysis and computational tests supporting the theory are given.Copyright © 2014 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 30: 1083–1102, 2014
Increases in insulin sensitivity among obese youth are associated with gene expression changes in whole blood
Authors: Miranda Danielle N. , Coletta Dawn K. , Mandarino Lawrence J. , Shaibi Gabriel Q. 
Published: January 2014

ObjectiveLifestyle intervention can improve insulin sensitivity in obese youth, yet few studies have examined the molecular signatures associated with these improvements. Therefore, the purpose of this study was to explore gene expression changes in whole blood that are associated with intervention‐induced improvements in insulin sensitivity.MethodsFifteen (7M/8F) overweight/obese (BMI percentile = 96.3 ± 1.1) Latino adolescents (15.0 ± 0.9 years) completed a 12‐week lifestyle intervention that included weekly nutrition education and 180 minutes of moderate–vigorous exercise per week. Insulin sensitivity was estimated by an oral glucose tolerance test and the Matsuda Index. Global microarray analysis profiling from whole blood was performed to examine changes in gene expression and to explore biological pathways that were significantly changed in response to the intervention.ResultsA total of 1,459 probes corresponding to mRNA transcripts (717 up, 742 down) were differentially expressed with a fold change ≥1.2. These genes were mapped within eight significant pathways identified, including insulin signaling, type 1 diabetes, and glycerophospholipid metabolism. Participants with increased insulin sensitivity exhibited five times the number of significant genes altered compared with nonresponders (1,144 vs. 230).ConclusionsThese findings suggest that molecular signatures from whole blood are associated with lifestyle‐induced health improvements among high‐risk Latino youth.
High‐dose busulfan–thiotepa with autologous stem cell transplantation followed by posterior fossa irradiation in young children with classical or incompletely resected medulloblastoma
Authors: Bergthold Guillaume , Kababri Maria El , Varlet Pascale , Dhermain Frederic , Sainte‐Rose Christian , Raquin Marie‐Anne , Kieffer Virginie , Goma Gisele , Grill Jacques , Valteau‐Couanet Dominique , Dufour Christelle 
Published: January 2014

BackgroundThe aim of the study is to evaluate the outcome of young children with high risk localized medulloblastomas (newly diagnosed classical or incompletely resected) treated by high‐dose busulfan–thiotepa with autologous stem cell rescue (ASCT) followed by focal radiation therapy (RT).ProcedureBetween September 1994 and January 2010, 19 children younger than 5 years old at diagnosis fulfilling the above inclusion criteria were treated at the Institute Gustave Roussy. After conventional chemotherapy, they received busulfan at a dose of 600 mg/m2 and thiotepa at a dose of 900 mg/m2 followed by ASCT. Focal RT was delivered at least 70 days after ASCT.ResultsThe median follow‐up was 40.5 months (range, 14.5–191.2 months). The 3‐year event‐free survival (EFS) and OS were 68% (95% CI 45–84%) and 84% (95% CI 61–94%), respectively. Acute toxicity consisted mainly in hepatic veno‐occlusive disease (6/19 patients) and bone marrow aplasia (all patients). No toxic death occurred. The Full Scale Intellectual Quotient tended to decrease over time at a mean rate of 0.9 point per year from the date of diagnosis.ConclusionsThis intensive treatment resulted in a high overall survival rate in young children with newly diagnosed non‐metastatic classic or incompletely resected MB. In spite of a high incidence of hepatic veno‐occlusive disease (32%), the acute toxicity was manageable. Delayed neuropsychological side effects remain main concerns. These results should to be confirmed in a larger cohort. Pediatr Blood Cancer 2014;61:907–912. © 2014 Wiley Periodicals, Inc.
The 253‐kb inversion and deep intronic mutations in UNC13D are present in North American patients with familial hemophagocytic lymphohistiocytosis 3
Authors: Qian Yaping , Johnson Judith A. , Connor Jessica A. , Valencia C. Alexander , Barasa Nathaniel , Schubert Jeffery , Husami Ammar , Kissell Diane , Zhang Ge , Weirauch Matthew T. , Filipovich Alexandra H. , Zhang Kejian 
Published: January 2014

BackgroundThe mutations in UNC13D are responsible for familial hemophagocytic lymphohistiocytosis (FHL) type 3. A 253‐kb inversion and two deep intronic mutations, c.118–308C > T and c.118–307G > A, in UNC13D were recently reported in European and Asian FHL3 patients. We sought to determine the prevalence of these three non‐coding mutations in North American FHL patients and evaluate the significance of examining these new mutations in genetic testing.ProcedureWe performed DNA sequencing of UNC13D and targeted analysis of these three mutations in 1,709 North American patients with a suspected clinical diagnosis of hemophagocytic lymphohistiocytosis (HLH).ResultsThe 253‐kb inversion, intronic mutations c.118–308C > T and c.118–307G > A were found in 11, 15, and 4 patients, respectively, in which the genetic basis (bi‐allelic mutations) explained 25 additional patients. Taken together with previously diagnosed FHL3 patients in our HLH patient registry, these three non‐coding mutations were found in 31.6% (25/79) of the FHL3 patients. The 253‐kb inversion, c.118–308C > T and c.118–307G > A accounted for 7.0%, 8.9%, and 1.3% of mutant alleles, respectively. Significantly, eight novel mutations in UNC13D are being reported in this study. To further evaluate the expression level of the newly reported intronic mutation c.118–307G > A, reverse transcription PCR and Western blot analysis revealed a significant reduction of both RNA and protein levels suggesting that the c.118–307G > A mutation affects transcription.ConclusionsThese specified non‐coding mutations were found in a significant number of North American patients and inclusion of them in mutation analysis will improve the molecular diagnosis of FHL3. Pediatr Blood Cancer 2014;61:1034–1040. © 2014 Wiley Periodicals, Inc.
Interactive role of depression, distress tolerance and negative urgency on non‐suicidal self‐injury
Authors: Peterson Claire M. , Davis‐Becker Kendra , Fischer Sarah 
Published: January 2014

ABSTRACTNegative affect often precedes non‐suicidal self‐injury (NSSI). Negative urgency (NU) and distress tolerance (DT) are associated with NSSI yet represent different trait‐like pathways to maladaptive affect regulation. This study examined the role of NU, (lack of) premeditation, depression and DT on NSSI in a sample of 884 undergraduates. Main effects for depression and NU emerged, with no main effects of DT. There was a significant three‐way interaction of NU, DT and depression, whereas no interaction was found for (lack of) premeditation. The influence of NU and depression on NSSI is enhanced when individuals have low perceived ability to tolerate distress. Copyright © 2014 John Wiley & Sons, Ltd.
Structural insights into FRS2α PTB domain recognition by neurotrophin receptor TrkB
Authors: Zeng Lei , Kuti Miklos , Mujtaba Shiraz , Zhou Ming‐Ming 
Published: January 2014

AbstractThe fibroblast growth factor receptor (FGFR) substrate 2 (FRS2) family proteins function as scaffolding adapters for receptor tyrosine kinases (RTKs). The FRS2α proteins interact with RTKs through the phosphotyrosine‐binding (PTB) domain and transfer signals from the activated receptors to downstream effector proteins. Here, we report the nuclear magnetic resonance structure of the FRS2α PTB domain bound to phosphorylated TrkB. The structure reveals that the FRS2α‐PTB domain is comprised of two distinct but adjacent pockets for its mutually exclusive interaction with either nonphosphorylated juxtamembrane region of the FGFR, or tyrosine phosphorylated peptides TrkA and TrkB. The new structural insights suggest rational design of selective small molecules through targeting of the two conjunct pockets in the FRS2α PTB domain. Proteins 2014; 82:1534–1541. © 2014 Wiley Periodicals, Inc.
Vibrational and mechanical properties of Si/Ge nanowires as resonators: A molecular dynamics study
Authors: Georgakaki D. , Ziogos O. G. , Polatoglou H. M. 
Published: January 2014

In this work, we examine the vibrational and mechanical properties of clamped‐clamped rectangular SixGe1−x and Si/SixGe1−x nanowires (NWs) using molecular dynamics simulations. A virtual atomic force microscope nanotip is used to drive the vibration. The frequency response, the beat vibration phenomenon and the calculation of mechanical properties such as quality factor Q and Young's modulus E are thoroughly analyzed. The influence of added mass and hydrogen passivation on the NW resonator performance is also demonstrated. The decreasing frequency trend with increasing Ge concentration was different for binary alloys and alloy superlattices, while it remained unaffected by the superlattice period. The beat vibration phenomenon driven by a single excitation was observed at elevated temperatures for all studied configurations. The resonance frequency decreases linearly with increasing temperature whereas the Q‐factor follows a power law decrease. The Young's modulus E obtained through stress–strain computational experiments is found to be overestimated compared to the classical beam theory. Frequency decreases linearly as more atoms are added to the resonator. For low temperatures, the quality factor of composite Si/Ge resonators increased from 104 to 105 at T = 23 K, after performing hydrogen passivation on the NW free surfaces. The frequency shift due to the change in stoichiometry in a Si NW, alongside with representative snapshots of the vibrational behavior.
Recombination dynamics and internal quantum efficiency in InGaN
Authors: Murotani Hideaki , Andoh Hiroya , Tsukamoto Takehiko , Sugiura Toko , Yamada Yoichi , Tabata Takuya , Honda Yoshio , Yamaguchi Masahito , Amano Hiroshi 
Published: January 2014

AbstractRecombination dynamics and internal quantum efficiency (IQE) of green luminescent InGaN nanowires with different crystalline qualities have been studied by means photoluminescence (PL) and time‐resolved PL spectroscopy. Temperature‐ and excitation‐power‐density‐dependent PL spectroscopy enabled to evaluate the IQE as a function of excitation power density. The shape of the efficiency curves at low temperature strongly depended on the magnitude of nonradiative recombination processes. This leads to the misestimation of the IQE in the lower quality nanowire. In addition, the PL decay curves were well described by a double exponential function both at 6 and 300 K. The PL decay time of the faster component was affected by nonradiative recombination processes even at low temperature. This indicated that the radiative recombination lifetime cannot be estimated from the PL decay time in the lower quality nanowire. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of an InGaN prelayer on the properties of InGaN/GaN quantum well structures
Authors: Davies Matthew J. , Massabuau Fabien C.‐P. , Dawson Philip , Oliver Rachel A. , Kappers Menno J. , Humphreys Colin J. 
Published: January 2014

AbstractIn this paper we report on the effects of including of an InGaN prelayer in an InGaN/GaN multiple quantum well (MQW) structure. Two equivalent 10 period In0.16Ga0.84N MQW structures were studied, one with a 24 nm thick In0.05Ga0.95N prelayer, one without. X‐ray diffraction measurements showed no evidence of strain relaxation in the structure containing the prelayer, while AFM revealed a 15% increase in average diameter of “V”‐defects. Temperature dependent photoluminescence (PL) showed the MQW structure, with the prelayer, to exhibit a higher room temperature internal quantum efficiency than the reference structure. PL excitation spectroscopy revealed an absorption and carrier transfer process associated with the InGaN prelayer, which created an additional recombination pathway resulting in a feature on the high energy side of the PL spectrum. Time‐resolved PL studies showed that this recombination had a weaker temperature sensitivity to that of the primary luminescence feature, and thus may be responsible for the enhanced PL intensity measured at 300 K. Monochromatic cathodoluminescence (CL) images showed the high energy feature originated from the “V”‐defects. It is thus suggested that the InGaN prelayer may provide a transfer mechanism for carriers in the prelayer into the semi‐polar QWs on the “V”‐defect facets. Alternatively the high energy emission may arise from QWs at the base of the stack that have parameters that are significantly different from the rest of the QWs. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effects of varying threading dislocation density on the optical properties of InGaN/GaN quantum wells
Authors: Davies Matthew J. , Dawson Philip , Massabuau Fabien C.‐P. , Oehler Fabrice , Oliver Rachel A. , Kappers Menno J. , Badcock Thomas J. , Humphreys Colin J. 
Published: January 2014

AbstractThe effects of the threading dislocation (TD) density on the optical properties of a series of comparable InxGa1–xN/ GaN multiple QW structures were studied. The TD density ranged from 2 × 107 cm–2, for a structure grown on a free‐standing GaN substrate, to 5 × 109 cm–2 grown on a sapphire substrate. Room temperature internal quantum efficiencies (IQEs) were determined by temperature dependent photoluminescence (PL); no systematic dependence of the IQE on the TD density was found. The excitation power density dependence of the efficiency was investigated, which also showed no systematic dependence on TD density. PL excitation spectroscopy was used to verify that equivalent carrier densities were generated within the QWs of each structure. The lack of systematic dependence of the optical properties on TD density is attributed to the strong carrier localisation in InGaN/GaN QWs. At the highest density of TDs studied, it is estimated that the average defect separation greatly exceeds the in‐plane diffusion lengths of electrons and holes; consequently the majority of carriers in the system are isolated from the TDs. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Status of GaN/SiC‐based LEDs and their application in solid state lighting
Authors: Kong Hua‐Shuang , Ibbetson James , Edmond John 
Published: January 2014

AbstractWith the advances in light‐emitting diodes (LED) efficiency over the last several years, solid‐state lighting in the marketplace has grown significantly. This includes outdoor full colour displays, street and parking deck lighting, indoor lighting and hand held devices. In each application, there is an optimization between the LED chips, the components they are encapsulated into and the lighting systems made from these components. In this paper, the latest developments in GaN/SiC chip design, and the most recent white LED component efficacy will be discussed. Recent and predicted lighting system efficiency in the near future will also be presented. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Enhancement of light output power on GaN‐based light‐emitting diodes using two‐direction stripe‐patterned sapphire substrate
Authors: Okuno Koji , Oshio Takahide , Shibata Naoki , Honda Yoshio , Yamaguchi Masahito , Amano Hiroshi 
Published: January 2014

AbstractTo achieve both the reduction of threading dislocation density (TDD) and the enhancement of light extraction efficiency (LEE) of light‐emitting diodes (LEDs), a two‐directional stripe‐patterned sapphire substrate (TPSS) was fabricated. First, a stripe pattern parallel to the a‐axis of Al2O3 was formed on an as‐received c ‐sapphire wafer and then a second stripe pattern rotated around 3° from the m‐axis of Al2O3 was formed on the first stripe PSS. The light output power of TPSS LEDs was around 1.25 times higher than that of LEDs on a flat sapphire substrate. This enhancement is caused by the increase of both the internal quantum efficiency (IQE) and the LEE. On the other hand, although the LED on TPSS with the second stripe just parallel to the m‐axis of Al2O3 showed a similar enhancement ratio of the light output power, the current leakage of this LED increased with the concentration of threading dislocations on the surface of LEDs. Stripes rotated 3° from the m‐axis of Al2O3 changed the growth mode and realized GaN films with a smooth surface without pit formation. Therefore, the misalignment of the stripe from the m‐axis of Al2O3 will become a new design parameter for realizing high‐efficiency reliable LEDs. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Leakage‐current reduction and improved on‐state performance of Au‐free AlGaN/GaN‐on‐Si Schottky diode by embedding the edge terminations in the anode region
Authors: Hu Jie , Lenci Silvia , Stoffels Steve , Jaeger Brice De , Groeseneken Guido , Decoutere Stefaan 
Published: January 2014

AbstractAlGaN/GaN Schottky barrier diodes (SBDs) have been fabricated on GaN‐on‐Si wafers (8‐inch) with Au‐free CMOS compatible technology. Two types of Edge Terminations have been investigated to suppress the leakage current with the conventional AlGaN/GaN Schottky Barrier Diodes fabricated on the same wafer as a reference. The External Edge Terminated‐SBD (EET‐SBD) shows a trend of reduction in leakage current by scaling down the spacing between the edge termination and the Schottky contact. By embedding the edge terminations inside the anode region named Gated Edge Terminated‐SBD (GET‐SBD), four orders of magnitude reduction in leakage current has been observed experimentally compared with the reference. Furthermore, anode recess was performed and its influences on both on‐ and off‐state characteristics were studied. The recessed EET‐SBD shows lower leakage current than the non‐recessed one. The forward voltage drop in EET‐SBD appears to be degraded by recess. The recessed GET‐SBD features the lowest leakage (1 µA/mm at VAC of –600 V) and improved on‐state performance (with VF of 1.15 V). With Anode‐to‐Cathode distance (LAC) of 10 µm, a breakdown voltage over 600 V in all three architectures has been achieved in both recessed and non‐recessed wafers. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)