bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinematics of turning maneuvers in the southern flying squirrel,Glaucomys volans
Authors: Bishop Kristin L. , Brim‐DeForest Whitney 
Published: April 2008

AbstractThe ability to change direction is essential to any animal that moves around in a complex, 3D environment. In this study we present the first 3D description of body positions during gliding turns in a mammalian gliding specialist, the southern flying squirrel,Glaucomys volans. In addition, we used these kinematic data to estimate the aerodynamic forces generated by the animals and rotational velocities and accelerations of the body while turning. These results were compared with similar measurements of flying squirrels during straight glides. The two individuals used in this study differed significantly in limb position asymmetries between the two sides of their bodies and also were significantly different in measures of turning performance. The individual with better performance used limb positions consistent with a primarily lift‐based turning mechanism (banked turn), whereas the individual with poorer performance used limb positions consistent with a primarily drag‐based turning mechanism (crabbed turn). Both individuals employed limb movements continuously through the gliding turn, but these movements did not have any consistent relationships with body rotations or lateral acceleration. As compared with straight glides, squirrels used significantly higher angles of attack and had lower lift‐to‐drag ratios, but did not differ in glide angle. Contrary to the typical view of maneuvering during gliding as a simple, static form of locomotion, the results presented here indicate that mammalian gliding is a complex behavior comprising the interplay of many components of limb position and wing shape that affect the balance of forces that control the turn.J. Exp. Zool. 309A:225–242, 2008. © 2008 Wiley‐Liss, Inc.
Two‐point dixon fat–water separation: Improving reliability and accuracy in phase correction algorithms
Authors: Schmidt Maria A. , Fraser Karlene M. 
Published: April 2008

AbstractPurposeTo propose an advanced phase‐correction region‐growing algorithm for two‐point fat–water separation suitable for parotid assessment, and to evaluate the general performance of phase‐correction algorithms.Materials and MethodsTwo region‐growing algorithms were evaluated in test objects and in head images: the original phase‐correction algorithm (OPC) and the advanced phase‐correction algorithm with voxel size manipulation (VSM) which includes: 1) starting the region‐growing process from images of lower resolution and subsequently stepping toward the original matrix size, and 2) limiting the use of low‐pass filters to fat–water interfaces with partial volume effectsResultsFundamental problems relate to biological tissue spectrum being poorly approximated by two discrete peaks for fat and water. The VSM algorithm was shown to be less noise‐sensitive, faster, and to produce a better approximation for the field inhomogeneity map. In head images (6 volunteers, 10 slices each) 43 errors were found with the OPC algorithm and only 6 errors with the VSM algorithm. Only the OPC algorithm produced errors surrounding the parotids (10 errors).ConclusionThe VSM algorithm provides a more accurate and less noise‐sensitive fat–water separation. This highly significant performance improvement allows the application of phase‐correction algorithms to a wider range of clinical applications. J. Magn. Reson. Imaging 2008. © 2008 Wiley‐Liss, Inc.
Diffusion‐weighted PROPELLER MRI for quantitative assessment of liver tumor necrotic fraction and viable tumor volume in VX2 rabbits
Authors: Deng Jie , Virmani Sumeet , Young Joseph , Harris Kathleen , Yang Guang‐Yu , Rademaker Alfred , Woloschak Gayle , Omary Reed A. , Larson Andrew C. 
Published: April 2008

AbstractPurposeTo test the hypothesis that diffusion‐weighted (DW)‐PROPELLER (periodically rotated overlapping parallel lines with enhanced reconstruction) MRI provides more accurate liver tumor necrotic fraction (NF) and viable tumor volume (VTV) measurements than conventional DW‐SE‐EPI (spin echo echo‐planar imaging) methods.Materials and MethodsOur institutional Animal Care and Use Committee approved all experiments. In six rabbits implanted with 10 VX2 liver tumors, DW‐PROPELLER and DW‐SE‐EPI scans were performed at contiguous axial slice positions covering each tumor volume. Apparent diffusion coefficient maps of each tumor were used to generate spatially resolved tumor viability maps for NF and VTV measurements. We compared NF, whole tumor volume (WTV), and VTV measurements to corresponding reference standard histological measurements based on correlation and concordance coefficients and the Bland–Altman analysis.ResultsDW‐PROPELLER generally improved image quality with less distortion compared to DW‐SE‐EPI. DW‐PROPELLER NF, WTV, and VTV measurements were strongly correlated and satisfactorily concordant with histological measurements. DW‐SE‐EPI NF measurements were weakly correlated and poorly concordant with histological measurements. Bland–Altman analysis demonstrated that DW‐PROPELLER WTV and VTV measurements were less biased from histological measurements than the corresponding DW‐SE‐EPI measurements.ConclusionDW‐PROPELLER MRI can provide spatially resolved liver tumor viability maps for accurate NF and VTV measurements, superior to DW‐SE‐EPI approaches. DW‐PROPELLER measurements may serve as a noninvasive surrogate for pathology, offering the potential for more accurate assessments of therapy response than conventional anatomic size measurements. J. Magn. Reson. Imaging 2008. © 2008 Wiley‐Liss, Inc.
A clinical comparison of rigid and inflatable endorectal‐coil probes for MRI and 3D MR spectroscopic imaging (MRSI) of the prostate
Authors: Noworolski Susan M. , Crane Jason C. , Vigneron Daniel B. , Kurhanewicz John 
Published: April 2008

AbstractPurposeTo compare the data quality and ease of use of four endorectal‐coil probe setups for prostate MRI.Materials and MethodsFour endorectal‐coil probe setups were compared: 1) air‐inflated probe; 2) perfluorocarbon (PFC)‐inflated probe; 3) rigid, smaller prototype coil; and 4) rigid, smaller coil designed for biopsying the prostate. Signal‐to‐noise ratio (SNR), positioning, shimming, MRI motion artifact, and MR spectroscopic imaging (MRSI) spectral quality were assessed.ResultsRigid coils provided approximately 2.5‐fold higher SNR than inflatable coils near the peripheral zone midline. The biopsy probe sensitivity decreased dramatically by the apex. The rigid probes, as compared to the inflatable probes, took longer to place (10 ± 2 vs. 7 ± 2 minutes, P < 0.0002), tended to be placed too superiorly, required repositioning more often (73% vs. 20%, P < 0.003), and had higher motion artifacts (P < 0.001). Shimming time was least for the PFC‐inflated probe (2 ± 0.5 minutes, P < 0.05). The air‐inflated probe produced larger linewidths (P < 0.01) and tended to have longer shim times (7 ± 4 minutes) and poorer spectral quality.ConclusionThe inflatable coil is a good clinical choice due to ease of use, good coverage, and low motion artifacts. PFC‐inflation is recommended as it provided higher quality data than air‐inflation. The rigid, smaller probes have higher SNR and produce less tissue distortion and may be preferred for certain applications. J. Magn. Reson. Imaging 2008. © 2008 Wiley‐Liss, Inc.
Semi‐implicit schemes for transient Navier–Stokes equations and eddy viscosity models
Authors: Davis Lisa G. , Pahlevani Faranak 
Published: April 2008

AbstractThis study presents two computational schemes for the numerical approximation of solutions to eddy viscosity models as well as transient Navier–Stokes equations. The eddy viscosity model is one example of a class of Large Eddy Simulation models, which are used to simulate turbulent flow. The first approximation scheme is a first order single step method that treats the nonlinear term using a semi‐implicit discretization. The second scheme employs a two step approach that applies a Crank–Nicolson method for the nonlinear term while also retaining the semi‐implicit treatment used in the first scheme. A finite element approximation is used in the spatial discretization of the partial differential equations. The convergence analysis for both schemes is discussed in detail, and numerical results are given for two test problems one of which is the two dimensional flow around a cylinder. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009
Well‐controlled 3D skeletal epoxy‐based monoliths obtained by polymerization induced phase separation
Authors: Tsujioka Norio , Ishizuka Norio , Tanaka Nobuo , Kubo Takuya , Hosoya Ken 
Published: April 2008

AbstractWe recently presented a short communication on the preparation of epoxy‐based monoliths possessing highly ordered structures by polymerization induced phase separation based on the spinodal decomposition. In this article, we describe in detail on reaction mechanisms and structural properties of the epoxy‐based monoliths with well‐controlled macropores in the micrometer range. We prepared epoxy‐based monoliths based on diglycidyl ether of bisphenol A, bis(4‐aminocyclohexyl)methane, and polyethylene glycol with a bicontinuous structure by in situ step‐growth polymerization. Different morphology of epoxy‐based monoliths could be obtained by changing formulation of monomers and porogenic solvents. Characterizations of their morphologies were performed using scanning electron microscopy, mercury intrusion porosimetry, small angle X‐ray scattering, and gas adsorption measurement (BET method). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3272–3281, 2008
Controlled polymerization of 2‐(diethylamino)ethyl methacrylate and its block copolymer with N‐isopropylacrylamide by RAFT polymerization
Authors: Liu Li , Wu Chenglin , Zhang Jiechun , Zhang Mingming , Liu Yuwei , Wang Xiaojuan , Fu Guoqi 
Published: April 2008

AbstractPoly(2‐(diethylamino)ethyl methacrylate) (PDEAEMA) homopolymers with low polydispersities were synthesized by reversible addition fragmentation chain transfer (RAFT) radical polymerization. The performances of two chain transfer agents, 2‐cyanoprop‐2‐yl dithiobenzoate and 4‐cyanopentanic acid dithiobenzoate (CPADB), were compared. It was found that the polymerization of 2‐(diethylamino) ethyl methylacrylate was under good control in the presence of CPADB with 4,4′‐azobis(4‐cyanopentanoic acid) (ACPA) as initiator in 1,4‐dioxane at 70 °C. The kinetic behaviors were investigated under different CPADB/ACPA molar ratios. A long polymerization inhibition period was observed at high [CPADB]/[ACPA] ratio. The influences of [CPADB]/[ACPA] ratio, monomer/[CPADB] ratio, and temperature were studied with respect to monomer conversion, molecular weight control, and polydispersity index (PDI). The PDI decreased from 1.21 to 1.12, as the CPADB/ACPA molar ratio changed from 2 to 10. The molecular weight of PDEAEMA could be controlled by monomer/CPADB molar ratio. The control over MW and PDI was improved as the temperature increased from 60 to 70 °C; however, an additional increase to 80 °C led to a loss of control. Using PDEAEMA macroRAFT agent, pH/thermo double‐responsive block copolymers of PDEAEMA and poly(N‐isopropylacrylamide) (PDEAEMA‐b‐PNIPAM) with narrow polydispersity (PDI, 1.24) were synthesized. The lower critical solution temperature of PDEAEMA‐b‐PNIPAM block copolymer depended on the environmental pH. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3294–3305, 2008
Q‐Space Analysis Applied to Polydisperse, Dense Random Aggregates
Authors: Hubbard J. A. , Eckels S. J. , Sorensen C. M. 
Published: April 2008

AbstractPolydisperse powders of spherical shell particles and nonspherical, three dimensionally dense aggregates were dispersed as turbulent jets through an abrupt orifice nozzle and in‐situ small angle light scattering measurements were made. In contrast to traditional studies, the light scattering data were plotted versus the scattering wave vector rather than the scattering angle; we call this q‐space analysis. For dense aggregates distinct power law trends emerged, similar to those discovered previously for spherical Mie scatterers. Moreover, when the system was very polydisperse, either with a broad bimodal or monotonic with extreme range, the q‐space analysis provided particle size distribution information about these aerosol systems which was unapparent when plotted as a function of the scattering angle.
Altered expression of 12S/MT‐RNR1, MT‐CO2/COX2, and MT‐ATP6 mitochondrial genes in prostate cancer
Authors: Abril Jesús , de Heredia Miguel López , González Laura , Clèries Ramon , Nadal Marga , Condom Enric , Aguiló Fernando , Gómez‐Zaera Montserrat , Nunes Virginia 
Published: April 2008

AbstractBACKGROUNDProstate cancer is one of the commonest cancers worldwide and is responsible for nearly 6% of all male cancer deaths. Despite this relevance, the mechanisms involved in the development and progression of this malignancy remain unknown. The involvement of polypeptides of the mitochondrial respiratory chain, the Krebs cycle and the glutathione antioxidant system in this type of cancer has been previously described, although no publication has focused on the expression of mitochondrial genes in the prostate of PCa patients.METHODSWe have determined by reverse transcription‐quantitative PCR (RT‐qPCR) the relative amount of the transcripts of eight mitochondrial genes (MT‐ND2, MT‐ND4, MT‐ND6, MT‐CYB, 12S/MT‐RNR1, 16S/MT‐RNR2, MT‐CO2/COX2, MT‐ATP6), and four nuclear genes (COX11, GSR, CS, ACO2), all of them key players in the normal metabolism of mitochondria. Additionally we analyzed the expression of Cyclophilin A (PPIA).RESULTSWe observed differential expression of mitochondrial 12S/MT‐RNR1, MT‐CO2/COX2, and MT‐ATP6 transcripts in tumor samples when compared to their paired normal samples.CONCLUSIONSThe amount of mitochondrial 12S/MT‐RNR1, MT‐CO2/COX2, and MT‐ATP6 transcripts is significantly decreased in tumor samples when compared to their paired normal sample, suggesting that mitochondrial gene expression is altered in PCa. Prostate 68:1086–1096, 2008. © 2008 Wiley‐Liss, Inc.
Three‐dimensional model of the human urotensin‐II receptor: Docking of human urotensin‐II and nonpeptide antagonists in the binding site and comparison with an antagonist pharmacophore model
Authors: Lescot Elodie , Sopkova‐de Oliveira Santos Jana , Colloc'h Nathalie , Rodrigo Jordi , Milazzo‐Segalas Isabelle , Bureau Ronan , Rault Sylvain 
Published: April 2008

AbstractHuman urotensin‐II (hU‐II) is a cyclic peptide that plays a central role in cardiovascular homeostasis and is considered to be the most potent mammalian vasoconstrictor identified to date. It is a natural ligand of the human urotensin‐II (hUT‐II) receptor, a member of the family of rhodopsin‐like G‐protein‐coupled receptors. To understand the molecular interactions of hU‐II and certain antagonists with the hUT‐II receptor, a model of the hUT‐II receptor in an active conformation with all its connecting loops was constructed by homology modeling. The initial model was placed in a pre‐equilibrated lipid bilayer and re‐equilibrated by several procedures of energy minimization and molecular dynamics simulations. Docking studies were performed for hU‐II and for a series of nonpeptide hUT‐II receptor antagonists in the active site of the modeled receptor structure. Results of the hU‐II docking study are in agreement with our previous work and with experimental data showing the contribution of the extracellular loops II and III to ligand recognition. The docking of hU‐II nonpeptide antagonists allows identification of key molecular interactions and confirms a previously reported hU‐II antagonist pharmacophore model. The results of the present studies will be used in structure‐based drug design for developing novel antagonists for the hUT‐II receptor. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Theory of the surface plasmon polariton–exciton interaction in multi‐layer systems
Authors: Schwieger S. , Vasa P. , Runge E. 
Published: April 2008

AbstractA thorough theoretical understanding of the interaction of excitons and surface plasmon polaritons (SPP) in metal–semiconductor hybrid structures is of fundamental importance for the design of SPP‐based devices. A theory to describe SPP–exciton interaction in a periodic multilayer film system is presented and demonstrated. In a hybrid system of gold nanowires on top of a GaAs/AlGaAs quantum well (QW), our calculations show the formation of coupled SPP–exciton modes. These are predicted to be observable in reflection spectra and by near‐field scanning optical microscopy. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mg‐doped InN and InGaN – Photoluminescence, capacitance–voltage and thermopower measurements
Authors: Ager J. W. , Miller N. , Jones R. E. , Yu K. M. , Wu J. , Schaff W. J. , Walukiewicz W. 
Published: April 2008

AbstractThe bandgap range of InGaN extends from the near‐IR (InN, 0.65 eV) to the ultraviolet. To exploit this wide tuning range in light generation and conversion applications, pn junctions are required. The large electron affinity of InN (5.8 eV) leads to preferential formation of native donor defects, resulting in excess electron concentration in the bulk and at surfaces and interfaces. This creates difficulties for p‐type doping and/or measuring of the bulk p‐type activity. Capacitance–voltage measurements, which deplete the n‐type surface inversion layer, have been used to show that Mg is an active acceptor in InN and Inx Ga1–x N for 0.2 < x < 1.0, i.e. over the entire composition range. Mg acceptors can be compensated by irradiation‐induced native donors. Thermopower measurements were used to provide definitive evidence that Mg‐doped InN has mobile holes between 200 K and 300 K. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of electrode pattern on light emission distribution in InGaN/GaN light emitting diode
Authors: Hwang Sungmin , Yoon Joosun , Shim Jongin , Yoo Kyungyul 
Published: April 2008

AbstractThe effect of geometrical electrode pattern on the blue InGaN/GaN multi‐quantum well (MQW) light emitting diode (LED) devices is investigated both theoretically and experimentally. A 3‐dimensional circuit model of an LED is constructed and then the corresponding circuit parameters are extracted. Circuit parameters of an LED consist of the resistances of the metallic film and epitaxial layer, and intrinsic diodes representing the light‐emitting active region. Both the transmission line model (TLM) and current‐voltage (I‐V) characteristics of LED are employed to extract circuit parameters experimentally. These circuit parameters are then applied to the circuit model to generate light emission patterns in a top‐surface emitting‐type LED. Experiment results verify that the emitting light distribution from fabricated LED coincides reasonably well with the theoretical results. This makes it possible to design an LED theoretically and predict its actual properties. The LED structure proposed using the model is shown to exhibit not only good light uniformity, but also higher light output power and lower voltage drop. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Voltage tunable wavelength LEDs
Authors: Soh C. B. , Chua S. J. , Hartono H. 
Published: April 2008

AbstractWe report on the growth and fabrication of a LED which emits light, tunable in color, as the injection current is increased from I = 1.0 mA to 40 mA. Two multiple quantum well (MQWs) structures, designated as A and B, are grown in the LEDs, with quantum dots embedded in MQWs B while MQWs A are conventional blue emitting quantum well layers. A broad photoluminescence spectrum ranging from 430 nm to 750 nm is measured, which is the result of spectral broadening attributed to the incorporation of quantum dots in the well layer of MQWs B coupled with the grading of Indium composition in the well of MQW B. This leads to a gradual change in the emission wavelength as the electron‐hole (e‐h) pairs recombine at the different stacked layers to give a transition from red, yellow, green and cyan as injection current increases. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Non‐lithographic nanopatterning of InGaN/GaN multiple quantum well nanopillars by focused ion beams
Authors: Wu S. E. , Hsueh T. H. , Liu C. P. , Sheu J. K. , Lai W. C. , Chang S. J. 
Published: April 2008

AbstractThis study proposes a new approach to fabrication of a high‐aspect‐ratio InGaN/GaN multiple quantum well nanopillar array. This fabrication technique utilizes focused ion beam milling with modified beam‐shape tuning technology. The samples used in this work have a light‐emitting diode (LED) structure grown by metal‐organic chemical‐vapour deposition. The modified beam‐shape tuning was performed by simultaneously stigmating and defocusing the ion beam. The structural and optical properties of the ion‐beam‐milled areas were examined by high resolution transmission electron microscopy and cathodoluminescence (CL). Typical nanopillars have diameters of about 100–150 nm and heights of about 600–1000 nm. The corresponding CL spectrum at room temperature revealed the main emission to be approximately 2.98 eV, and it showed a blue shift of about 35 meV compared to as‐grown samples. A maskless, site‐controlled approach to the fabrication of nano‐LEDs was demonstrated in this work. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nanopatterning GaN with microspheres
Authors: Ng W. N. , Wang X. H. , Leung C. H. , Lai P. T. , Choi H. W. 
Published: April 2008

AbstractIn this work, the fabrication and characterization of nano‐pillar arrays on GaN substrates using the technique of microsphere lithography have been demonstrated. Self‐assembled hexagonally‐packed silica microsphere array were formed on GaN wafers by the methods of spin coating and tilting. By precisely controlling the process parameters, a monolayer of microsphere array can be formed over a wide region, acting as a hard‐mask for pattern transfer of the nanostructures. After dry etching, arrays of nano‐pillars were formed on the surface of the wafer. The structure properties of the ordered nanostructures were characterized by SEM images, while photoluminescence (PL) measurements revealed a twofold enhancement of light emission intensity. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polychromatic emission from fluorescent‐microsphere‐coated LEDs
Authors: Hui K. N. , Ng W. N. , Leung C. H. , Lai P. T. , Choi H. W. 
Published: April 2008

AbstractWhite light LEDs using fluorescent microspheres as color conversion agents are demonstrated. The hexagonal ordered arrays of green and red fluorescence microspheres were coated on the blue micro‐hexLED centered at 480 nm by microspheres coating technique. At optimal mixed portion of green and red microspheres, white light emission is generated by a combination of blue light from LED and down conversion of fluorescence emission of green and red microspheres by blue excitation light. An overall efficiency of more than 70% is obtained by this new approach. The enhanced efficiency is attributed to two main properties of ordered micropsheres arrays: (1) efficient color conversion and (2) efficient light out‐coupling via volumetric light scattering. The resultant LED has lumnious efficiency of 31.8 lm/W with CIE coordinates of (0.30, 0.31). We have demonstrated an alternative solution of producing white light emission, apart from existing down conversion of yellow phosphor with blue or UV LED and multichip LEDs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)