bluuebunny/crossref_metadata_2025 huggingface dataset:
Cholesteryl Ester Transfer Protein in Metabolic Syndrome
Authors: Sandhofer Anton , Kaser Susanne , Ritsch Andreas , Laimer Markus , Engl Julia , Paulweber Bernhard , Patsch Josef R. , Ebenbichler Christoph F.
Published: April 2008

Objective: Low high‐density lipoprotein cholesterol (HDL‐C), hypertriglyceridemia, and small dense‐low density lipoprotein (LDL) are key components of metabolic syndrome (MS). Cholesteryl ester transfer protein (CETP) mediates the transfer of triglycerides (TGs) from TG‐rich lipoproteins to HDL and LDL particles in exchange for cholesteryl esters, leading to low HDL‐C and small dense‐LDL. The aim of this study was to investigate the role of CETP in subjects with MS.

Research Methods and Procedures: In a cross‐sectional cohort of 234 middle‐aged men and 252 women randomly selected from the Salzburg Atherosclerosis Prevention Program in Subjects at High Individual Risk (SAPHIR) study, MS was diagnosed according to the National Cholesterol Education Program guidelines. CETP mass was determined by enzyme‐linked immunosorbent assay and LDL size‐by‐gradient polyacrylamide gel electrophoresis.

Results: Men and women with MS had lower HDL‐C (45 ± 7 vs. 58 ± 13 and 48 ± 10 vs. 71 ± 14 mg/dL for men and women, respectively; p < 0.001 for all) and higher TG levels (222 ± 71 vs. 98 ± 54 and 167 ± 67 vs. 90 ± 35 mg/dL for men and women, respectively; p < 0.001 for all) than healthy subjects. LDL size was lower in subjects with MS (256 ± 11 Å vs. 267 ± 11 Å and 262 ± 10 Å vs. 273 ± 8 Å for men and women, respectively; p < 0.001 for all). CETP mass was higher in men with MS (1.87 ± 0.78 vs. 1.40 ± 0.65 μg/mL; p < 0.001) but not in women (1.74 ± 0.79 vs. 1.62 ± 0.62 μg/mL). CETP mass correlated inversely with LDL size in both men and women (r = −0.19, p < 0.01 and r = −0.13, p < 0.05 in men and women, respectively).

Discussion: MS is associated with increased CETP mass in men. Increased CETP mass may be responsible for reduced HDL‐C and reduced LDL particle diameter in MS.
Effects of Acquired Obesity on Endothelial Function in Monozygotic Twins
Authors: Pietiläinen Kirsi H. , Bergholm Robert , Rissanen Aila , Kaprio Jaakko , Häkkinen Anna‐Maija , Sattar Naveed , Yki‐Järvinen Hannele
Published: April 2008

Objective: To determine whether acquired obesity or accompanying metabolic changes such as adiponectin deficiency, insulin resistance, dyslipidemia, or visceral fat are associated, independent of genetic influences, with endothelial dysfunction by studying young adult monozygotic (MZ) twin pairs discordant for obesity.

Research Methods and Procedures: Nine obesity‐discordant (intra‐pair difference in BMI, 3.8 to 10.1 kg/m2) and nine concordant (0 to 2.3 kg/m2) 24‐ to 27‐year‐old MZ twin pairs were identified from a population‐based FinnTwin16‐sample. Endothelial function was measured by blood flow responses to intrabrachial infusions of an endothelium‐dependent (acetylcholine) and an endothelium‐independent (sodium nitroprusside) vasodilator. Whole body insulin sensitivity was measured using the euglycemic insulin clamp technique, and forearm and body composition were measured with magnetic resonance imaging and DXA. In addition, serum levels of adiponectin, high‐sensitivity C‐reactive protein, and lipids were determined.

Results: The heavier co‐twins of the discordant pairs had significantly lower whole body insulin sensitivity than the leaner co‐twins. Blood flows/muscle volume during infusions of acetylcholine and sodium nitroprusside were not altered by obesity. However, intra‐pair differences in serum adiponectin, intra‐abdominal fat, and C‐reactive protein were significantly correlated with those in endothelial function. Only the relationship between intra‐pair differences in adiponectin and endothelial function persisted in multiple linear regression analysis. Obesity‐concordant co‐twins had comparable insulin sensitivity and endothelial function.

Discussion: In young adult MZ twins discordant for obesity, acquired adiponectin deficiency rather than obesity per se is an independent correlate of endothelial dysfunction.
Spin mode calculations in nanometric magnetic rings: Localization effects in the vortex and saturated states
Authors: Montoncello F. , Giovannini L. , Nizzoli F.
Published: April 2008

We study how a varying applied magnetic field influences the localization of the spin excitations in a Permalloy nanoring. The eigenfrequencies and eigenvectors of the excitations are calculated directly in the frequency domain with the dynamical matrix method, which recently proven to be successful in explaining the spin mode spectrum measured by the Brillouin scattering in rings [G. Gubbiotti et al., Phys. Rev. Lett. 97, 247203 (2006)]. When the ring is in the vortex equilibrium state at a field different from zero, we found that the localization of the (m,0) azimuthal modes may take place either where the internal field has a minimum or a maximum, depending on the mode frequency and index m. The saturated phase is characterized by a variety of modes, which may localize in the lateral arms of the ring, in the upper/lower sectors in the direction of the applied field, and at the inner or outer borders.
Electronic structure of copper phthalocyanine: A comparative density functional theory study
Authors: Marom Noa , Hod Oded , Scuseria Gustavo E. , Kronik Leeor
Published: April 2008

We present a systematic density functional theory study of the electronic structure of copper phthalocyanine (CuPc) using several different (semi)local and hybrid functionals and compare the results to experimental photoemission data. We show that semilocal functionals fail qualitatively for CuPc primarily because of underbinding of localized orbitals due to self-interaction errors. We discuss an appropriate choice of functional for studies of CuPc/metal interfaces and suggest the Heyd–Scuseria–Ernzerhof screened hybrid functional as a suitable compromise functional.
Estimating the yield and characteristics of random network carbon nanotube transistors
Authors: Ishida Masahiko , Nihey Fumiyuki
Published: April 2008

The device characteristics of field-effect transistors featuring a random network of carbon nanotubes (CNTs) as a channel material were investigated by means of a numerical simulation. The simulations of the conductivity of CNTs, contact resistances, and metallic to semiconducting ratio indicated that, even with a random network composed of one-third metallic CNTs, the maximum yield rate can be dramatically increased by shortening the CNTs. The error rate can be reduced to 0.0014% when the length of CNTs is one-tenth of the source-to-drain distance. The conductance of the devices, on/off ratio, and methods to improve these characteristics are also discussed.
Analysis of a penny-shaped crack in magnetoelectroelastic materials
Authors: Wang B. L. , Sun Y. G. , Zhang H. Y.
Published: April 2008

Cracks in magnetoelectroelastic fracture have been extensively assumed to be impermeable or permeable to the electromagnetic fields. Past analysis suggested that even in piezoelectric cracking, the permeability of the medium inside the crack has a substantial influence on the crack-tip fields and the crack opening displacement. This paper performs a self-consistent analysis for magnetoelectroelastic cracking. An internal penny-shaped crack in a magnetoelectroelastic material under remote magnetoelectromechanical loads is investigated. Effects of electric and magnetic permeabilities inside the cracks in magnetoelectroelastic media are clarified. It is found that the self-consistent approach and the traditional ideal assumptions (impermeable and permeable assumptions) to the crack-face electric and magnetic boundary conditions produce substantial differences for the crack-tip quantities, such as the field intensity factors, energy release rate, and crack opening displacement.
In situ radiation damage studies of LaxSr1−3x∕2TiO3 perovskites
Authors: Smith Katherine L. , Lumpkin Gregory R. , Blackford Mark G. , Colella Michael , Zaluzec Nestor J.
Published: April 2008

Seven perovskite samples in the LaxSr1−3x∕2TiO3 solid solution series were monitored in situ during irradiation with 1.0MeV Kr2+ ions using the intermediate voltage electron microscope-Tandem User Facility (IVEM) at Argonne National Laboratory. All the perovskites pass through the crystalline-amorphous transformation. However, the critical temperature for amorphisation Tc of the LaxSr1−3x∕2TiO3 perovskites varies nonlinearly with composition, decreasing from 394±3K for SrTiO3 to a minimum of 275±1K for La0.2Sr0.7TiO3, then increasing with composition again to 865±3K for La0.67TiO3. In combination with the work of previous authors, the electron microscopy results and IVEM data in this study suggest that there is a vacancy-assisted recovery mechanism in the cubic perovskites with compositions in the range 0<x<0.2 that may not be directly associated with the cubic-tetragonal phase transformation and that vacancy-enhanced amorphisation occurs for both cubic and orthorhombic perovskites with compositions in the range x=∼0.2–0.67.
Ion-radical synergy in HfO2 etching studied with a XeF2/Ar+ beam setup
Authors: Gevers P. M. , Beijerinck H. C. W. , van de Sanden M. C. M. , Kessels W. M. M.
Published: April 2008

To gain more insight into fundamental aspects of the etching behavior of Hf-based high-k materials in plasma etch reactors, HfO2 films were etched in a multiple-beam setup consisting of a low energy Ar+ ion beam and a XeF2 radical beam. The etch rate and etch products were monitored by real-time ellipsometry and mass spectrometry, respectively. Although etching of HfO2 in XeF2/Ar+ chemistry is mainly a physical effect, an unambiguous proof of the ion-radical synergistic effect for the etching of HfO2 is presented. The etch yield for 400 eV Ar+ ions at a substrate temperature of 300 °C was 0.3 atoms/ion for Ar+ sputtering and increased to 2 atoms/ion when XeF2 was also supplied. The etch yield proved to follow the common square root of ion energy dependence both for pure sputtering and radical enhanced etching, with a threshold energy at room temperature of 69±17 eV for Ar+ ions and 54±14 eV for Ar+ ions with XeF2.
Mechanism of mobility increase of the two-dimensional electron gas in AlGaN∕GaN heterostructures under small dose gamma irradiation
Authors: Kurakin A. M. , Vitusevich S. A. , Danylyuk S. V. , Hardtdegen H. , Klein N. , Bougrioua Z. , Danilchenko B. A. , Konakova R. V. , Belyaev A. E.
Published: April 2008

The effect of a small dose of gamma irradiation on transport characteristics of the two-dimensional electron gas (2DEG) in AlGaN∕GaN heterostructures was investigated. It is shown that the carrier concentration remains practically unchanged after an irradiation dose of 106rad, while the 2DEG mobility exhibits a considerable increase. The results are explained within a model that takes into account the relaxation of elastic strains and structural-impurity ordering occurring in the barrier layer under irradiation.
Potential superhard cubic spinel CSi2N4: First-principles investigations
Authors: Zhang Xinyu , Chen Zhouwen , Du Huijing , Yang Chao , Ma Mingzhen , He Julong , Tian Yongjun , Liu Riping
Published: April 2008

The structural and mechanical properties of the cubic spinel CSi2N4 (c-CSi2N4) are studied by first-principles total energy calculations based on the density-functional theory. It is found that the calculated lattice constants and bulk modulus are in good agreement with previous calculations. The elastic constants show that c-CSi2N4 is mechanically stable. Based on the microscopic hardness model, c-CSi2N4 is predicted to be a superhard material with the calculated Vickers hardness of 52.07GPa, which is 57.79% higher than that of the cubic spinel Si3N4. The origin of the hardness enhancement is discussed in terms of the density of states and the chemical bonding analysis. It is also found that the elastic anisotropy and the ductility are improved in comparison with those of the cubic spinel Si3N4.
Topological invariants in the study of a chaotic food chain system
Authors: Duarte Jorge , Januário Cristina , Martins Nuno
Published: April 2008

The study of ecological systems has generated deep interest in exploring the complexity of chaotic food chains. The role of chaos in ecosystems is not entirely understood. One approach to have a better comprehension of ecological chaos is by analyzing it in mathematical models of basic food chains. In this article it is considered a classical chaotic food chain model from the literature. We use the theory of symbolic dynamics to study the topological entropy and the parameter space ordering of kneading sequences associated with one-dimensional maps that reproduce significant aspects of the model dynamics. The topological entropy allows us to distinguish different chaotic states in some realistic system parameter region. Another numerical invariant is introduced in order to characterize isentropic dynamics. Studying a set of maps with the same topological entropy, we exhibit numerical results about the relation between the second topological invariant and each of the control parameters in consideration. This work provides an illustration of how our understanding of ecological models can be enhanced by the theory of symbolic dynamics.
The C3N− anion: First detection of its electronic luminescence in rare gas solids
Authors: Turowski Michał , Gronowski Marcin , Boyé-Péronne Séverine , Douin Stéphane , Monéron Laurence , Crépin Claudine , Kołos Robert
Published: April 2008

The 193nm laser irradiation of cyanoacetylene (HCCCN) that was isolated in rare gas solids led to a long-lived luminescence (origin at 3.58eV), which was assigned to the ãΣ+3-X̃Σ+1 system of cyanoacetylide (CCCN−). The identification, which involved N15 and H2 isotopic substitution studies, is based on vibronic spacings in the phosphorescence spectrum (compared to previous infrared absorption measurements and to theoretical results regarding CCCN− vibrational frequencies), as well as on a BD(T)/cc-pVTZ prediction for the singlet-triplet energy gap in this anion (3.61eV). The same emission was also generated from Kr∕HC3N mixtures subjected to a glow electric discharge immediately before the solidification (cold-window-radial-discharge technique).
Quasidegenerate scaled opposite spin second order perturbation corrections to single excitation configuration interaction
Authors: Casanova David , Rhee Young Min , Head-Gordon Martin
Published: April 2008

Scaled opposite spin (SOS) second order perturbative corrections to single excitation configuration interaction (CIS) are extended to correctly treat quasidegeneracies between excited states. Two viable methods, termed as SOS-CIS(D0) and SOS-CIS(D1), are defined, implemented, and tested. Each involves one empirical parameter (plus a second for the SOS-MP2 ground state), has computational cost that scales with the fourth power of molecule size, and has storage requirements that are cubic, with only quantities of the rank of single excitations produced and stored during iterations. Tests on a set of low-lying adiabatic valence excitation energies and vertical Rydberg excitations of organic and inorganic molecules show that the empirical parameter can be acceptably transferred from the corresponding nondegenerate perturbation theories without any further fitting. Further tests on higher excited states show that the new methods correctly perform for surface crossings for which nondegenerate approaches fail. Numerical results show that SOS-CIS(D0) appears to treat Rydberg excitations in a more balanced way than SOS-CIS(D1) and is, therefore, likely to be the preferred approach. It should be useful for exploring excited state geometries, transition structures, and conical intersections for states of medium to large organic molecules that are dominated by single excitations.
Improved photoluminescence and electrical properties of Eu- and Gd-codoped bismuth titanate ferroelectric thin films
Authors: Ruan Kaibin , Chen Xinman , Liang Tong , Wu Guangheng , Bao Dinghua
Published: April 2008

Eu- and Gd-codoped bismuth titanate [Bi3.15Eu0.425Gd0.425Ti3O12], thin films as well as Bi3.15Eu0.85Ti3O12 (BEuT) and Bi3.15Gd0.85Ti3O12 (BGdT) thin films were prepared on indium-tin-oxide-coated glass substrates by chemical solution deposition and the photoluminescence, ferroelectric, and dielectric properties of the thin films were investigated. All the thin films exhibited a polycrystalline bismuth-layered perovskite structure. Photoluminescence studies showed that the enhancement of emission intensities for two Eu3+ emission transitions of D05→F17 (594nm) and D05→F27 (617nm) was observed for the BEGT thin films as compared to BEuT thin films. This photoluminescence improvement can be attributed to Eu content of BEGT thin films close to quenching concentration of BEuT thin films and local distortion of crystal field surrounding the Eu3+ activator induced by different ionic radii of Eu3+ and Gd3+ ions. Electrical measurements indicated that BEGT thin films had larger remanent polarization and higher dielectric constant than BGdT and BEuT thin films prepared under the same experimental conditions. These results suggest that codoping of rare earth ions such as Eu and Gd in bismuth titanate thin films is an effective way to improve photoluminescence and electrical properties of the thin films.
Stress-dependent scaling behavior of subcoercive field dynamic ferroelectric hysteresis in Pb(Zn1∕3Nb2∕3)O3-modified Pb(Zr1∕2Ti1∕2)O3 ceramic
Authors: Yimnirun R. , Wongdamnern N. , Triamnak N. , Unruan M. , Ngamjarurojana A. , Ananta S. , Laosiritaworn Y.
Published: April 2008

Scaling behavior of subcoercive field dynamic ferroelectric hysteresis under influence of stress was investigated in Pb(Zn1∕3Nb2∕3)O3-modified Pb(Zr1∕2Ti1∕2)O3 (PZT) bulk ceramic. The scaling relation of hysteresis area ⟨A⟩ against frequency f, field amplitude E0, and stress σ for the minor loops takes a form of ⟨A−Aσ=0⟩∝f−0.42E03.65σ0.24, which is very similar to that of soft and hard PZT ceramics. However, slightly faster responses to f and E0 indicate the ease of polarization orientation in this simpler domain structure ceramic as compared to commercial PZT ceramics.
Effective complex permittivity of two-phase random composite media: A test of the two exponent phenomenological percolation equation
Authors: Myroshnychenko Viktor , Brosseau Christian
Published: April 2008

The nature of percolation in continuum inhomogeneous media is a current topic of debate. In this work, Monte Carlo and finite element simulations of the effective complex permittivity, ε=ε′−iε″, of two-phase random composite media are analyzed by using the two exponent phenomenological percolation equation (TEPPE) by McLachlan [J. Am. Ceram. Soc. 73, 2187 (1990); Phys. Rev. B 56, 1236 (1987); Phys. Rev. B 58, 14880 (1998); Phys. Rev. B 58, 13558 (1998); Phys. Rev. B 67, 024206 (2003)]. The continuum-percolation system consists of two-dimensional equilibrium distributions of randomly distributed monodisperse circular and partially penetrable disks (or parallel, infinitely long, identical, partially penetrable circular cylinders) throughout a host matrix. The study is performed on a set of calculations, covering wide ranges of various parameters, including the intrinsic constituent permittivity, the surface fraction, and the degree of impenetrability. In our analysis, we first determine the parameters that characterize the critical behavior at the percolation threshold. Our data suggest that the TEPPE does not fit the simulation data well over the entire range of surface fraction and whatever is the degree of impenetrability considered. This is attributed, in part, to the fact that the effective medium approximation (restricted to dipolar interactions only) explicitly ignores the local-field fluctuations. Moreover, the mixtures exhibit clustering in equilibrium, which is not conceptually incorporated in the TEPPE, i.e., the inclusions form a cluster with a percolating spongelike topology accompanied by a strongly dependent shape of the radial distribution function on the degree of impenetrability. It is argued that further efforts are still needed to fully grasp the numerically (and experimentally) observed features of the effective properties of dielectric heterostructures.
Homogeneous nucleation in supersaturated vapors of methane, ethane, and carbon dioxide predicted by brute force molecular dynamics
Authors: Horsch Martin , Vrabec Jadran , Bernreuther Martin , Grottel Sebastian , Reina Guido , Wix Andrea , Schaber Karlheinz , Hasse Hans
Published: April 2008

Molecular dynamics (MD) simulation is applied to the condensation process of supersaturated vapors of methane, ethane, and carbon dioxide. Simulations of systems with up to a 106 particles were conducted with a massively parallel MD program. This leads to reliable statistics and makes nucleation rates down to the order of 1030m−3s−1 accessible to the direct simulation approach. Simulation results are compared to the classical nucleation theory (CNT) as well as the modification of Laaksonen, Ford, and Kulmala (LFK) which introduces a size dependence of the specific surface energy. CNT describes the nucleation of ethane and carbon dioxide excellently over the entire studied temperature range, whereas LFK provides a better approach to methane at low temperatures.
Surface functionalization of cubic boron nitride films for biological sensing applications
Authors: Zhou Y. L. , Zhi J. F. , Wang P. F. , Chong Y. M. , Zou Y. S. , Zhang W. J. , Lee S. T.
Published: April 2008

Surface functionalization and modification scheme of cubic boron nitride (cBN) films deposited by chemical vapor deposition was demonstrated. A homogeneous layer of amino groups was bonded covalently on the B and/or N atoms of cBN surface via a photochemical reaction with allylamine. X-ray photoelectron spectroscopy was carried out to verify comprehensively each stage of the surface modification process. Gold nanoparticles (AuNPs) were self-assembled on the amine-terminated cBN surface, and a dense and well-distributed AuNPs monolayer was obtained. Modification of amine-terminated cBN films with amine-modified DNA probes presents an example of applications as DNA biosensors.
Piezoelectrets from laminated sandwiches of porous polytetrafluoroethylene films and nonporous fluoroethylenepropylene films
Authors: Huang Jinfeng , Zhang Xiaoqing , Xia Zhongfu , Wang Xuewen
Published: April 2008

In this paper, the piezoelectric properties of laminated films made of polytetrafluoroethylene (PTFE) and tetrafluoroethylene-hexafluoropropylene (FEP) copolymer by an improved process and charged by a corona method are investigated by measurements of the pressure dependence of the piezoelectric d33 coefficents, the isothermal decay of d33 at various temperatures, and thermally stimulated discharge current spectra. The results show that the structure of the laminated films is mechanically stable. The quasistatic piezoelectric d33 coefficents can reach 400pC∕N and they are relatively independent of the static pressure in the range up to 16kPa. The decay of the d33 coefficients is primarily due to charge detrapping. Compared to polypropylene ferroelectrets, the thermal stability of the piezoelectric activity in such laminated films at 90°C is improved by a factor of 2 with respect to the percentage of the d33 values remaining. The dominant drift path of the detrapped charges at temperatures of about 130°C is most likely along the surface of the PTFE fibers, while charge drift through the solid layer of FEP is possibly prevailing at temperatures of around 210°C.
Metal-insulator transition-induced electrical oscillation in vanadium dioxide thin film
Authors: Lee Yong Wook , Kim Bong-Jun , Lim Jung-Wook , Yun Sun Jin , Choi Sungyoul , Chae Byung-Gyu , Kim Gyoungock , Kim Hyun-Tak
Published: April 2008

In this letter, we report an observation of room temperature electrical oscillation in vanadium dioxide (VO2), a representative strongly correlated material showing a metal-insulator transition. An electric circuit for the oscillation is simply composed of a voltage source and two-terminal VO2 thin film device serially connected with a standard resistor. The systematic procedures where the oscillation occurred were explained based on the electrical relationship between the VO2 device and resistor, and the generation window of the oscillation was determined. In particular, the oscillation frequency could be controlled by adjusting an external voltage and increased up to >0.5MHz.
Hybrid optoelectronics: A polymer laser pumped by a nitride light-emitting diode
Authors: Yang Y. , Turnbull G. A. , Samuel I. D. W.
Published: April 2008

We demonstrate indirect electrically pumped lasing in a hybrid polymer laser. The lasers comprise a corrugated fluorene copolymer waveguide on an InGaN light-emitting diode and were driven under nanosecond pulsed operation. We observe the onset of distributed feedback lasing at 568nm for peak drive currents above 144A. Angle-resolved photoluminescence measurements identify the lasing mechanism as band edge feedback from a photonic stopband in the TE0 waveguide mode.
Nanoindentation hardness anisotropy of alumina crystal: A molecular dynamics study
Authors: Nishimura Kenji , Kalia Rajiv K. , Nakano Aiichiro , Vashishta Priya
Published: April 2008

Atomistic mechanisms of the initial stage of plasticity during nanoindentation are studied by molecular dynamics simulations for three surface orientations of alumina crystal. The simulations predict significant anisotropy and indentation depth dependence of the hardness value at the nanometer scale. The nanohardness anisotropy is found to arise from orientation-dependent dislocation activities. In the (0001) basal plane indentation, prism dislocations are emitted, followed by basal and pyramidal dislocations, to form massive subsurface defects; prism and pyramidal dislocations are emitted on (011¯0) and (21¯1¯0) prism plane indentations, respectively, to cause modest deformations. Stacking faults are also observed because these dislocations are extended to Shockley partial dislocations.
Exchange-induced terahertz minigap in InAs∕GaSb type II and broken-gap quantum wells
Authors: Xu W. , Wei X. F. , Zhang J.
Published: April 2008

We theoretically demonstrate that the exchange effect induced by the carrier-carrier interaction can cause the hybridization of the electron and hole dispersion relations in InAs∕GaSb-based type II and broken-gap quantum well (QW) systems. As a result, a terahertz minigap at the anticrossing points of the conduction and valence bands can be induced by the interlayer electron-hole coupling via the Coulomb interaction. It is shown that the many-body effect is another important source of the hybridization of the dispersion relations in InAs∕GaSb QW systems.
Selective delivery of β cell antigen to dendritic cells
in vivo
leads to deletion and tolerance of autoreactive CD8
+
T cells in NOD mice
Authors: Mukhopadhaya Arunika , Hanafusa Tadashi , Jarchum Irene , Chen Yi-Guang , Iwai Yoshiko , Serreze David V. , Steinman Ralph M. , Tarbell Kristin V. , DiLorenzo Teresa P.
Published: April 2008

Type 1 diabetes (T1D) is an autoimmune disease resulting from defects in central and peripheral tolerance and characterized by T cell-mediated destruction of islet β cells. Cytotoxic CD8
+
T cells, reactive to β cell antigens, are required for T1D development in the NOD mouse model of the disease, and CD8
+
T cells specific for β cell antigens can be detected in the peripheral blood of T1D patients. It has been evident that in nonautoimmune-prone mice, dendritic cells (DCs) present model antigens in a tolerogenic manner in the steady state, e.g., in the absence of infection, and cause T cells to proliferate initially but then to be deleted or rendered unresponsive. However, this fundamental concept has not been evaluated in the setting of a spontaneous autoimmune disease. To do so, we delivered a mimotope peptide, recognized by the diabetogenic CD8
+
T cell clone AI4, to DCs in NOD mice via the endocytic receptor DEC-205. Proliferation of transferred antigen-specific T cells was initially observed, but this was followed by deletion. Tolerance was achieved because rechallenge of mice with the mimotope peptide in adjuvant did not induce an immune response. Thus, targeting of DCs with β cell antigens leads to deletion of autoreactive CD8
+
T cells even in the context of ongoing autoimmunity in NOD mice with known tolerance defects. Our results provide support for the development of DC targeting of self antigens for treatment of chronic T cell-mediated autoimmune diseases.
The Soft Spaces of Local Economic Development
Authors: Haughton Graham , Allmendingerr Phil
Published: April 2008

This article examines soft spaces, soft outcomes and soft infrastructure, trying to make some connections between them. We argue that soft spaces of governance constitute one of the most important but little understood components of contemporary sub-national economic development policy.
Particle Filter Tracking without Dynamics
Authors: Ortegon-Aguilar Jaime , Bayro-Corrochano Eduardo
Published: April 2008

People tracking is an interesting topic in computer vision. It has applications in industrial areas such as surveillance or human‐machine interaction. Particle Filters is a common algorithm for people tracking; challenging situations occur when the target′s motion is poorly modelled or with unexpected motions. In this paper, an alternative to address people tracking is presented. The proposed algorithm is based in particle filters, but instead of using a dynamical model, it uses background subtraction to predict future locations of particles. The algorithm is able to track people in omnidirectional sequences with a low frame rate (one or two frames per second). Our approach can tackle unexpected discontinuities and changes in the direction of the motion. The main goal of the paper is to track people from laboratories, but it has applications in surveillance, mainly in controlled environments.
Haptic Manipulation of Deformable Objects in Hybrid Bilateral Teleoperation System
Authors: Ibarra-Zannatha Juan Manuel , Marmolejo-Rivas Claudia , Ferre-Pérez Manuel , Aracil-Santonja Rafael , Cobos-Guzmán Salvador
Published: April 2008

The aim of this work is the integration of a virtual environment containing a deformable object, manipulated by an open kinematical chain virtual slave robot, to a bilateral teleoperation scheme based on a real haptic device. The virtual environment of this hybrid bilateral teleoperation system combines collision detection algorithms, dynamical, kinematical and geometrical models with a position–position and/or force–position bilateral control algorithm, to produce on the operator side the reflected forces corresponding to the virtual mechanical interactions, through a haptic device. Contact teleoperation task over the virtual environment with a flexible object is implemented and analysed.
Operation Strategy for a Low‐Cost Easy‐Operation Cassino Hexapod
Authors: Carbone Giuseppe , Shrot Aviral , Ceccarelli Marco
Published: April 2008

This paper presents operation strategies for a hexapod walking machine that has been designed and built at the Laboratory of Robotics and Mechatronics (LARM) at the University of Cassino. Special care has been addressed in proposing and describing a suitable mechanical design and architecture that can be easily operated by a PLC with on–off logic. Experimental tests are reported in order to show feasibility and operational capability of the proposed design.
Does Subepithelial Hemorrhage Cause Persistence of Laryngeal Granuloma?
Authors: Yumoto Eiji , Sanuki Tetsuji , Miyamaru Satoru , Kumai Yoshihiko
Published: April 2008

Objectives: To determine the incidence of black spots after resolution of laryngeal granuloma (LG), to compare the disease duration from the beginning of treatment to resolution between patients with and without black spots, and to assess the histologic findings of LG in resected or biopsied specimens.

Study Design: Retrospective.

Methods: Forty‐six patients with LG on the cartilaginous portion of the vocal fold were included. Their clinical records were reviewed. Histologic specimens were re‐examined.

Results: Causes of LG were postintubation in 10 patients, unilateral vocal fold immobility in 1, Candida infection in 1, and were not specified in 34 (either hyperfunctional vocal abuse, laryngopharyngeal regurgitation, or both). Of the 10 patients with postintubation LG, 9 resolved; of the 33 patients with LG from other causes, 21 resolved. Of the 28 resolved patients, 12 developed a black spot at the previous lesion site. Of the 18 patients whose LG resolved without surgical intervention, 11 developed a black spot at the previous lesion site, and the remaining 7 patients did not develop any black spots. The treatment period until LG resolution was significantly longer among patients with a black spot than those without a spot (P = .0372). Histologic examination revealed the presence of hemosiderin accumulation accompanied by infiltration of lymphocytes and macrophages in 8 of the 16 patients who had their LGs resected or biopsied.

Conclusions: Accumulation of hemosiderin in the subepithelial layer, together with little blood flow and dense connective tissue in the cartilaginous portion of the vocal fold, are important factors contributing to the persistence of LG.
Gene Transfer in Human Vestibular Epithelia and the Prospects for Inner Ear Gene Therapy
Authors: Kesser Bradley W. , Hashisaki George T. , Holt Jeffrey R.
Published: April 2008

Transfer of exogenous genetic material into the mammalian inner ear using viral vectors has been characterized over the last decade. A number of different viral vectors have been shown to transfect the varying cell types of the nonprimate mammalian inner ear. Several routes of delivery have been identified for introduction of vectors into the inner ear while minimizing injury to existing structures and at the same time ensuring widespread distribution of the agent throughout the cochlea and the rest of the inner ear.

These studies raise the possibility that gene transfer may be developed as a potential strategy for treating inner ear dysfunction in humans. Furthermore, a recent report showing successful transfection of excised human vestibular epithelia offers proof of principle that viralgene transfer is a viable strategy for introduction andexpression of exogenous genetic material to restore function to the inner ear. Human vestibular epithelia were harvested from patients undergoing labyrinthectomy, either for intractable Ménière's disease or vestibular schwannoma resection, and cultured for as long as 5 days. In those experiments, recombinant, multiply‐deleted, replication‐deficient adenoviral vectors were used to transfect and express a reporter gene as well as the functionally relevant gene, wild‐typeKCNQ4, a potassium channel gene that when mutated causes the autosomal dominant HL DFNA2.

Here, we review the current state of viral‐mediated gene transfer in the inner ear and discuss different viral vectors, routes of delivery, and potential applications of gene therapy. Emphasis is placed on experiments demonstrating viral transfection of human inner ear tissue and implications of these findings and for the future of gene therapy in the human inner ear.
Change of Acoustic Parameters Before and After Treatment in Laryngopharyngeal Reflux Patients
Authors: Jin Bong Joon , Lee Yong Seop , Jeong Seung Won , Jeong Jin Hyeok , Lee Seung Hwan , Tae Kyung
Published: April 2008

Objectives: To evaluate the usefulness of acoustic parameters as an indicator of laryngopharyngeal reflux (LPR) treatment efficacy.

Study Design: A prospective case series analysis.

Materials and Methods: From January to September 2005, we prospectively analyzed 40 patients who were diagnosed with laryngopharyngeal reflux by 24‐hour ambulatory double‐probe pH monitoring. Laryngopharyngeal reflux patients were treated medically and voice analysis was conducted three times: before treatment, 1 to 2 months after treatment, and 3 to 4 months after treatment. Jitter, shimmer, and harmonic‐to‐noise ratio (HNR) were analyzed as the acoustic parameters. Pre‐ and posttreatment reflux symptom index and reflux finding score were documented.

Results: Jitter, shimmer, and HNR had improved significantly at 1 to 2 months after treatment and were maintained at 3 to 4 months after treatment. Jitter was significantly correlated with reflux symptom index.

Conclusion: Acoustic parameters can be used as indicators of treatment efficacy for laryngopharyngeal reflux disease.
Intelligibility and first passage times in complex urban networks
Authors: Blanchard Philippe , Volchenkov Dimitri
Published: April 2008

Topology of urban environments can be represented by means of graphs. We explore the graph representations of several compact urban patterns by random walks. The expected time of recurrence and the expected first passage time to a node scales apparently linearly in all urban patterns we have studied. In space syntax theory, a positive relation between the local property of a node (qualified by connectivity or by the recurrence time) and the global property of the node (estimated in our approach by the first passage time to it) is known as intelligibility. Our approach, based on random walks, allows us to extend the notion of intelligibility onto the entire domain of complex networks and graph theory.
Availability of prey resources drives evolution of predator–prey interaction
Authors: Friman Ville-Petri , Hiltunen Teppo , Laakso Jouni , Kaitala Veijo
Published: April 2008

Productivity is predicted to drive the ecological and evolutionary dynamics of predator–prey interaction through changes in resource allocation between different traits. Here we report results of an evolutionary experiment where prey bacteria
Serratia marcescens
was exposed to predatory protozoa
Tetrahymena thermophila
in low- and high-resource environments for approximately 2400 prey generations. Predation generally increased prey allocation to defence and caused prey selection lines to become more diverse. On average, prey became most defensive in the high-resource environment and suffered from reduced resource use ability more in the low-resource environment. As a result, the evolution of stronger prey defence in the high-resource environment led to a strong decrease in predator-to-prey ratio. Predation increased temporal variability of populations and traits of prey. However, this destabilizing effect was less pronounced in the high-resource environment. Our results demonstrate that prey resource availability can shape the trade-off allocation of prey traits, which in turn affects multiple properties of the evolving predator–prey system.
Social transmission of nectar-robbing behaviour in bumble-bees
Authors: Leadbeater Ellouise , Chittka Lars
Published: April 2008

Social transmission of acquired foraging techniques is rarely considered outside of a vertebrate context. Here, however, we show that nectar robbing by bumble-bees (
Bombus terrestris
)—an invertebrate behaviour of considerable ecological significance—has the potential to spread through a population at the accelerated rates typical of social transmission. Nectar robbing occurs when individuals either bite through the base of a flower to ‘steal’ nectar (primary robbing) or use robbing holes that others have made (secondary robbing). We found that experience of foraging from robbed flowers significantly promoted the development of primary robbing in previously legitimate foragers, thus implying that the acquisition of nectar robbing by one individual will facilitate its adoption in others. Our findings suggest that the positive feedback effects of social transmission may potentially play an ecologically important role in the relationship between plants and pollinators.
Analysis of Cortical Arrays fromTradescantia virginianaat High Resolution Reveals Discrete Microtubule Subpopulations and Demonstrates That Confocal Images of Arrays Can Be Misleading
Authors: Barton Deborah A. , Vantard Marylin , Overall Robyn L.
Published: April 2008

Cortical microtubule arrays are highly organized networks involved in directing cellulose microfibril deposition within the cell wall. Their organization results from complex interactions between individual microtubules and microtubule-associated proteins. The precise details of these interactions are often not evident using optical microscopy. Using high-resolution scanning electron microscopy, we analyzed extensive regions of cortical arrays and identified two spatially discrete microtubule subpopulations that exhibited different stabilities. Microtubules that lay adjacent to the plasma membrane were often bundled and more stable than the randomly aligned, discordant microtubules that lay deeper in the cytoplasm. Immunolabeling revealed katanin at microtubule ends, on curves, or at sites along microtubules in line with neighboring microtubule ends. End binding 1 protein also localized along microtubules, at microtubule ends or junctions between microtubules, and on the plasma membrane in direct line with microtubule ends. We show fine bands in vivo that traverse and may encircle microtubules. Comparing confocal and electron microscope images of fluorescently tagged arrays, we demonstrate that optical images are misleading, highlighting the fundamental importance of studying cortical microtubule arrays at high resolution.
The Role of Mobile Phones in Family Communication
Authors: Devitt Kerry , Roker Debi
Published: April 2008

Whilst there is a wealth of research into family communication and family relationships, there is little information about whether (and if so how) mobile phones have impacted on these processes. The authors’ study involved individual semi‐structured interviews with 60 families, including parents/carers and young people aged 11–17, to investigate this further. The interviews explored how mobile phones are used in family communication; participants’ views about the benefits and disadvantages of mobile phone use; and issues around safety, surveillance and privacy. The findings show that young people and parents see mobiles as a key way for families to keep in touch, and to monitor and ensure young people’s safety. However, some participants felt there was a downside to this, in relation to some young people either withdrawing into their own social worlds, or having a false feeling of security as a result of having a mobile. Gender differences in views and usage were also found. The paper concludes with some general comments about the role of mobile phones in family life.
Microsatellite and mitochondrial haplotype diversity reveals population differentiation in the tiger shrimp (Penaeus monodon) in the Indo‐Pacific region
Authors: You E.‐M. , Chiu T.‐S. , Liu K.‐F. , Tassanakajon A. , Klinbunga S. , Triwitayakorn K. , de la Peña L. D. , Li Y. , Yu H.‐T.
Published: April 2008

The black tiger shrimp (Penaeus monodon) is an ecologically and economically important penaeid species and is widely distributed in the Indo‐Pacific region. Here we investigated the genetic diversity of P. monodon (n = 355) from eight geographical regions by genotyping at 10 microsatellite loci. The average observed heterozygosity at various loci ranged from 0.638 to 0.743, indicating a high level of genetic variability in this region. Significant departures from Hardy–Weinberg equilibrium caused by heterozygote deficiency were recorded for most loci and populations. Pairwise FST and RST values revealed genetic differentiation among the populations. Evidence from the assignment test showed that the populations in the West Indian Ocean were unique, whereas other populations examined were partially admixed. In addition, the non‐metric multidimensional scaling analysis indicated the presence of three geographic groups in the Indo‐Pacific region, i.e. the African populations, a population from western Thailand and the remaining populations as a whole. We also sequenced and analysed the mitochondrial control region (mtCR) in these shrimp stocks to determine whether the nuclear and mitochondrial genomes show a similar pattern of genetic differentiation. A total of 262 haplotypes were identified, and nucleotide divergence among haplotypes ranged from 0.2% to 16.3%. Haplotype diversity was high in all populations, with a range from 0.969 to 1. Phylogenetic analysis using the mtCR data revealed that the West Indian Ocean populations were genetically differentiated from the West Pacific populations, consistent with the microsatellite data. These results should have implications for aquaculture management and conservation of aquatic diversity.
The impact of a leptin gene SNP on beef calf weaning weights
Authors: DeVuyst E. A. , Bauer M. L. , Cheng F.‐C. , Mitchell J. , Larson D.
Published: April 2008

Prior research indicates that a SNP at position 305 of exon 2 in the leptin gene affects milk production in dairy cows. Dairy cows with at least one copy of the T allele have been shown to have higher milk production than CC cows. If that effect carries over to beef breeds, it is reasonable to expect that CT and TT beef cows will wean heavier calves than CC beef cows. We tested this hypothesis for a herd of mixed breed cows using anova. Results indicated that both crossbred CT and TT beef cows wean significantly heavier beef calves than CC crossbred beef cows. A lack of observations generally hinders detection of significance in other breeds. However, two other comparisons were found to be significant. The results suggest further investigation into the link between leptin genotype and calf weaning weights. Aside from interest to animal scientists, these results have the potential to alter mating and replacement selection decisions by cow–calf producers, given the importance of weaning weights on profitability.
The role of 18F‐FDOPA and 18F‐FDG–PET in the management of malignant and multifocal phaeochromocytomas
Authors: Taïeb D. , Tessonnier L. , Sebag F. , Niccoli‐Sire P. , Morange I. , Colavolpe C. , De Micco C. , Barlier A. , Palazzo F. F. , Henry J. F. , Mundler O.
Published: April 2008

Background  18F‐DOPA has emerged as a promising tool in the localization of chromaffin‐tissue‐derived tumours. Interestingly, phaeochromocytomas (PHEO) are also FDG avid.

Aim and methods The aim of this study was to retrospectively evaluate the results of 18F‐FDOPA and/or 18F‐FDG–PET in patients with PHEO and paragangliomas (PGLs) and to compare the outcome of this approach with the traditional therapeutic work‐up. Nine patients with non‐MEN2 related PHEO or PGL were evaluated. At the time of the PET studies, the patients were classified into three groups based on their clinical history, conventional and SPECT imaging. The groups were malignant disease (n = 5, 1 VHL), apparently unique tumour site in patients with previous surgery (n = 1, SDHB) and multifocal tumours (n = 3, 1 VHL, 1 SDHD). 18F‐FDOPA and 18F‐FDG–PET PET/CT were then performed in all patients.

Results  PET successfully identified additional tumour sites in five out of five patients with metastatic disease that had not been identified with SPECT + CI. Whilst tumour tracer uptake varied between patients it exhibited a consistently favourable residence time for delayed acquisitions. 18F‐FDOPA uptake (SUVmax) was superior to 18F‐FDG uptake in cases of neck PGL (three patients, four tumours). If only metastatic forms and abdominal PGLs were considered, 18F‐FDG provided additional information in three cases (two metastatic forms, one multifocal disease with SDHD mutation) compared to 18F‐FDOPA.

Conclusions  Our results suggest that tumour staging can be improved by combining 18F‐FDOPA and 18F‐FDG in the preoperative work‐up of patients with abdominal and malignant PHEOs. 18F‐FDOPA is also an effective localization tool for neck PGLs. MIBG however, still has a role in these patients as MIBG and FDOPA images did not completely overlap.