bluuebunny/crossref_metadata_2025 huggingface dataset:
Overexpression of OSBP-related protein 2 (ORP2) induces changes in cellular cholesterol metabolism and enhances endocytosis
Authors: Hynynen Riikka , Laitinen Saara , Käkelä Reijo , Tanhuanpää Kimmo , Lusa Sari , Ehnholm Christian , Somerharju Pentti , Ikonen Elina , Olkkonen Vesa M.
Published: August 2005

ORP2 [OSBP (oxysterol-binding protein)-related protein 2] belongs to the 12-member mammalian ORP gene/protein family. We characterize in the present study the effects of inducible ORP2 overexpression on cellular cholesterol metabolism in HeLa cells and compare the results with those obtained for CHO cells (Chinese-hamster ovary cells) that express ORP2 constitutively. In both cell systems, the prominent phenotype is enhancement of [14C]cholesterol efflux to all extracellular acceptors, which results in a reduction of cellular free cholesterol. No change was observed in the plasma membrane cholesterol content or distribution between raft and non-raft domains upon ORP2 expression. However, elevated HMG-CoA (3-hydroxy-3-methylglutaryl-CoA) reductase activity and LDL (low-density lipoprotein) receptor expression, as well as enhanced transport of newly synthesized cholesterol to a cyclodextrin-accessible pool, suggest that the ORP2 expression stimulates transport of cholesterol out of the endoplasmic reticulum. In contrast with ORP2/CHO cells, the inducible ORP2/HeLa cells do not show down-regulation of cholesterol esterification, suggesting that this effect represents an adaptive response to long-term cholesterol depletion in the CHO cell model. Finally, we provide evidence that ORP2 binds PtdIns(3,4,5)P3 and enhances endocytosis, phenomena that are probably interconnected. Our results suggest a function of ORP2 in both cholesterol trafficking and control of endocytic membrane transport.
A recently identified member of the glutathione transferase structural family modifies cardiac RyR2 substate activity, coupled gating and activation by Ca2+ and ATP
Authors: Dulhunty Angela F. , Pouliquin Pierre , Coggan Marjorie , Gage Peter W. , Board Philip G.
Published: August 2005

The recently discovered CLIC-2 protein (where CLIC stands for chloride intracellular channel), which belongs to the ubiquitous glutathione transferase structural family and is expressed in the myocardium, is a regulator of native cardiac RyR2 (ryanodine receptor 2) channels. Here we show that recombinant CLIC-2 increases [3H]ryanodine binding to native and purified RyR channels, enhances substate activity in individual channels, increases the number of rare coupled gating events between associated RyRs, and reduces activation of the channels by their primary endogenous cytoplasmic ligands, ATP and Ca2+. CLIC-2 (0.2–10 μM) added to the cytoplasmic side of RyR2 channels in lipid bilayers depressed activity in a reversible, voltage-independent, manner in the presence of activating (10–100 μM) or sub-activating (100 nM) cytoplasmic Ca2+ concentrations. Although the number of channel openings to all levels was reduced, the fraction and duration of openings to substate levels were increased after exposure to CLIC-2. CLIC-2 reduced increases in activity induced by ATP or adenosine 5′-[β,γ-imido]triphosphate. Depression of channel activity by CLIC-2 was greater in the presence of 100 μM cytoplasmic Ca2+ than with 100 nM or 10 μM Ca2+. Further, CLIC-2 prevented the usual ∼50-fold increase in activity when the cytoplasmic Ca2+ concentration was increased from 100 nM to 100 μM. The results show that CLIC-2 interacts with the RyR protein by a mechanism that does not require oxidation, but is influenced by a conserved Cys residue at position 30. CLIC-2 is one of only a few cytosolic inhibitors of cardiac RyR2 channels, and may suppress their activity during diastole and during stress. CLIC-2 provides a unique probe for substate activity, coupled gating and ligand-induced activation of cardiac RyR channels.
Spectroscopy of Ar–SH and Ar–SD. I. Observation of rotation-vibration transitions of a van der Waals mode by double-resonance spectroscopy
Authors: Sumiyoshi Yoshihiro , Katsunuma Hajime , Suma Kohsuke , Endo Yasuki
Published: August 2005

Rotation-vibration transitions of a van der Waals bending vibration, P=1∕2←3∕2, of the Ar–SH∕SD (XΠ2) complexes in the electronic ground state have been observed by applying newly developed microwave–millimeter-wave double-resonance spectroscopy. The rotational energy-level structure for the two isotopomers, with hyperfine structure due to the hydrogen or deuterium nuclei and parity doublings in the P=1∕2 state, has now been clarified. Detailed explanation of the double-resonance technique is also given.
Comparison of rovibronic density of asymmetric versus symmetric NO2 isotopologues at dissociation threshold: Broken symmetry effects
Authors: Jost R. , Michalski G. , Thiemens M.
Published: August 2005

We have measured the rovibronic densities of four symmetric (C2v) and two asymmetric (Cs) isotopologues of nitrogen dioxide just below their photodissociation threshold. At dissociation threshold and under jet conditions the laser-induced fluorescence abruptly disappears because the dissociation into NO(Π1∕22)+O(P23) is much faster than the radiative decay. As a consequence, in a narrow energy range below D0, the highest bound rovibronic energy levels of J=1∕2 and J=3∕2 can be observed and sorted. A statistical analysis of the corresponding rovibronic density, energy spacing, and rovibronic transition intensities has been made. The observed intensity distributions are in agreement with the Porter-Thomas distribution. This distribution allows one to estimate the number of missing levels, and therefore to determine and compare the rovibronic and the vibronic densities. The four symmetric NO2 isotopologues, O16N14O16, O18N14O18, O16N15O16, and O18N15O18, have, respectively, a sum of J=1∕2 and J=3∕2 rovibronic densities of 18±0.8, 18.3±1.4, 18.4±2.7, and 19.8±3.5∕cm−1, while for the two asymmetric isotopologues, O18N14O16 and O18N15O16, the corresponding densities are 20.9±4.5 and 23.6±5.6∕cm−1. The corresponding vibronic densities are in agreement only if we include both the merging of symmetry species (from those of C2v to those of Cs) and the contribution of the long-range tail(s) of the potential-energy surface along the dissociation coordinate. The effects of isotopic substitution on dissociation rates and the possible relation to mass-independent isotopic fractionation are discussed.
Fabrication of a glass-coated metal tip for synchrotron-radiation-light-irradiated scanning tunneling microscopy
Authors: Akiyama Kotone , Eguchi T. , An T. , Hasegawa Y. , Okuda T. , Harasawa A. , Kinoshita T.
Published: August 2005

A method to fabricate a glass-coated tungsten tip and the performance of the tip in scanning tunneling microscopy (STM) under irradiation of the synchrotron radiation light are reported. A tungsten tip was first coated with glass, and then the glass layer on the tip apex was removed by a focused ion beam. The bare area of the tip apex is less than 5μm in length. Using the tip, atomically resolved STM images were obtained in ultrahigh vacuum conditions without significant contaminations. STM studies under the irradiation revealed that the coating is effective in blocking photoinduced electrons impinging on the sidewall of the tip and in extracting photoelectron current emitted from a small area below the tip apex.
Predicting atomic dopant solvation in helium clusters: The MgHen case
Authors: Mella Massimo , Calderoni Gabriele , Cargnoni Fausto
Published: August 2005

We present a quantum Monte Carlo study of the solvation and spectroscopic properties of the Mg-doped helium clusters MgHen with n=2–50. Three high-level [MP4, CCSD(T), and CCSDT] MgHe interaction potentials have been used to study the sensitivity of the dopant location on the shape of the pair interaction. Despite the similar MgHe well depth, the pair distribution functions obtained in the diffusion Monte Carlo simulations markedly differ for the three pair potentials, therefore indicating different solubility properties for Mg in Hen. Moreover, we found interesting size effects for the behavior of the Mg impurity. As a sensitive probe of the solvation properties, the Mg excitation spectra have been simulated for various cluster sizes and compared with the available experimental results. The interaction between the excited P1 Mg atom and the He moiety has been approximated using the diatomics-in-molecules method and the two excited Π1 and Σ1 MgHe potentials. The shape of the simulated MgHe50 spectra shows a substantial dependency on the location of the Mg impurity, and hence on the MgHe pair interaction employed. To unravel the dependency of the solvation behavior on the shape of the computed potentials, exact density-functional theory has been adapted to the case of doped Hen and various energy distributions have been computed. The results indicate the shape of the repulsive part of the MgHe potential as an important cause of the different behaviors.
Isomers of GeNO and Ge(NO)2: Production and infrared absorption of GeNO and ONGeNO in solid Ar
Authors: Chou Jun-Bahn , Bahou Mohammed , Lee Yuan-Pern , Rayner David , Simard Benoit
Published: August 2005

Crystalline germanium was ablated with light at 532nm from a frequency-doubled neodymium: yttrium aluminum garnet laser, and the resultant plume reacted with NO before deposition onto a substrate at 13K. Lines in group A at 1543.8 and 3059.7cm−1 that become enhanced at the initial stage of irradiation at 308 or 193nm and also after annealing are attributed to ν1 and 2ν1 of GeNO. Lines in group B at 1645.5 and 1482.8cm−1 that become diminished after further irradiation of the matrix at 308 or 193nm but become enhanced after annealing are attributed to symmetric NO stretch (ν1) and antisymmetric NO stretch (ν7) of ONGeNO. The assignments were derived based on wave numbers and isotopic ratios observed in the experiments with N15- and O18-isotopic substitutions and predicted with quantum-chemical calculations. Quantum-chemical calculations with density-functional theories (B3LYP and BLYP/aug-cc-pVTZ) predict four stable isomers of GeNO, six isomers of Ge2NO, and four isomers of Ge(NO)2, with linear GeNO, cyc-GeNGeO, and cyc-GeONNO having the least energies, respectively. The formation mechanisms of GeNO and ONGeNO are discussed. In addition, a weak line at 1417.0cm−1 and two additional lines associated with minor matrix sites at 1423.0 and 1420.3cm−1 are assigned to GeNO−.
Dielectric media based on isolated metallic nanostructures
Authors: Kempa T. , Carnahan D. , Olek M. , Correa M. , Giersig M. , Cross M. , Benham G. , Sennett M. , Ren Z. , Kempa K.
Published: August 2005

We study the dielectric properties of nanocomposites in the 0–1.5-GHz frequency regime. These composites consist of electrically insulated metallic nanoparticles and carbon nanotubes, the elongated nanostructures in this study, uniformly dispersed in a dielectric matrix. We find that the properties of these composites depend crucially on the shape and monodispersity of the nanoparticles. While at high concentrations the spherical nanoparticles cause only slight modification of the dielectric function of the composite with respect to the matrix, the elongated nanoparticles produce composites with an enhanced real part of the dielectric function and low imaginary part. Our theory, which is in excellent agreement with these results, suggests specific ways to further improve the dielectric properties of the composites.
A Jacobi-Wilson description coupled to a block-Davidson algorithm: An efficient scheme to calculate highly excited vibrational levels
Authors: Ribeiro Fabienne , Iung Christophe , Leforestier Claude
Published: August 2005

We present a new approach based on the block-Davidson scheme which provides eigenvalues and eigenvectors of highly excited (ro) vibrational states of polyatomic molecules. The key ingredient is a prediagonalized-perturbative scheme applied to a subspace of a curvilinear normal-mode basis set. This approach is coupled to the Jacobi vector description recently developed by our group [C. Leforestier, A. Viel, F. Gatti, C. Muñoz, and C. Iung, J. Chem. Phys. 114, 2099 (2001)], and applied to the HFCO and H2CO molecules, which represent the main difficulties of such calculations for any available method. The first one presents a significant state density because of its low symmetry and the presence of a fluorine atom, while strong resonances and intermode couplings occur in H2CO. This study establishes the robustness, the numerical efficiency, and the versatility of the method which is compared to the regular Lanczos and Davidson schemes. It is also shown that the eigenvectors can be obtained within a given accuracy easily set by the user. This point constitutes one of the main advantages of the method as very few potential-energy surfaces achieve an accuracy of the order of a wave number for highly excited states. Furthermore, this method allows one to restrict the calculations to selected energy levels based on their zero-order descriptions.
Electrical and optical properties of Pb(Mg1∕3Nb2∕3)O3–PbTiO3 thin films prepared by chemical solution deposition
Authors: Liu A. Y. , Meng X. J. , Xue J. Q. , Sun J. L. , Chen J. , Chu J. H.
Published: August 2005

92 % Pb ( Mg 1 ∕ 3 Nb 2 ∕ 3 ) O 3 – 8 % PbTiO 3 (PMNT) thin films have been prepared on Pt∕Ti∕SiO2∕Si substrate with a LaNiO3 (LNO) buffer layer and on sapphire substrate by a chemical solution deposition method, respectively. X-ray diffraction analysis shows that the PMNT thin films on Pt∕Ti∕SiO2∕Si substrate are polycrystalline with (110)-preferential orientation. Pt∕PMNT∕Pt capacitors have been fabricated and show a ferroelectric character with a spontaneous polarization (Ps) of 25.2μC∕cm2 and a remanent polarization (Pr) of 6.56μC∕cm2. The dielectric constant (εr) and the dissipation factor (tanδ) at 1 kHz are 680 and 0.014, respectively. The band-gap energy of the PMNT thin films on the sapphire substrate was found to be about 4.03 eV by the optical transmission spectra measurement. The optical constants (n, k) of the PMNT thin films in the wavelength range of 2.5–12.6 μm were obtained by infrared spectroscopic ellipsometry measurement.
PT-invariant periodic potentials with a finite number of band gaps
Authors: Khare Avinash , Sukhatme Uday
Published: August 2005

We obtain the band edge eigenstates and the midband states for the complex, generalized associated Lamé potentials VPT(x)=−a(a+1)msn2(y,m)−b(b+1)msn2(y+K(m),m)−f(f+1)msn2(y+K(m)+iK′(m),m)−g(g+1)msn2(y+iK′×(m),m), where y≡ix+β, and there are four parameters a, b, f, g. By construction, this potential is PT-invariant since it is unchanged by the combined parity (P) and time reversal (T) transformations. This work is a substantial generalization of previous work with the associated Lamé potentials V(x)=a(a+1)msn2(x,m)+b(b+1)msn2(x+K(m),m) and their corresponding PT-invariant counterparts VPT(x)=−V(ix+β), both of which involving just two parameters a,b. We show that for many integer values of a,b,f,g, the PT-invariant potentials VPT(x) are periodic problems with a finite number of band gaps. Further, using supersymmetry, we construct several additional, complex, PT-invariant, periodic potentials with a finite number of band gaps. We also point out the intimate connection between the above generalized associated Lamé potential problem and Heun’s differential equation.
Photoconductivity sampling of low-temperature-grown Be-doped GaAs layers
Authors: Eusèbe H. , Roux J.-F. , Coutaz J.-L. , Krotkus A.
Published: August 2005

The dynamical electrical properties of annealed low-temperature-grown GaAs layers moderately doped with beryllium are studied using photoconductive sampling. Picosecond electrical pulses are sampled using an interdigitated metal-semiconductor-metal structure. These time-resolved experiments supported by numerical simulation allow us to determine electron and hole mobilities of, respectively, 540 and 90cm2∕V∕s. We also demonstrate that the free-electron trapping process is saturating under high-optical-density excitation. From these experiments, we get an electron trapping cross section of σn=1×10−13cm2.
Superfluidity and charged vortices in systems with spontaneous interlayer coherence in the low-density limit
Authors: Shevchenko S. I. , Nasedkin K. A.
Published: August 2005

The conditions for formation of a bound state between two-dimensional spatially separated electron and hole in a magnetic field normal to the plane of motion of the carriers are investigated. The binding energy, effective mass, and electric polarizability of the electron-hole pair are found as functions of the distance d between conducting layers. The features of the superfluidity of a Bose gas of electron-hole pairs in the case of low density are analyzed. It is established that quantized vortices in the superfluid phase have real electric charge, the value of which depends on the density of pairs and the distance between layers. In the case of small d and high magnetic fields the vortex charge q=νe, where ν is the filling factor of the lowest Landau level by carriers. The stability of the Bose gas of pairs against transition to the crystalline state is investigated, and it is shown that at small d the pair crystallization temperature Tm is substantially below the superfluid transition temperature Tc. With increasing d the temperature Tm grows more rapidly than Tc, and there exists a critical value d at which the superfluid phase vanishes.
Stabilization of the magnetic resonance position by a harmonized field
Authors: Ivanchenko E. A.
Published: August 2005

A two-level system in a magnetic field with a periodic temporal modulation that stabilizes the position of the magnetic resonance is investigated in the density matrix formalism. An exact solution is found for the density matrix at resonance. It is shown that at resonance the probability of a spin-flip transition is independent of the form of the field, i.e., the main resonance is stable against harmonized variation of the longitudinal and transverse components of the magnetic field. The Bloch polarization vector and the geometric phase at resonance are calculated. A differential equation for the transition probability is obtained. The dependence of the time-averaged probability of a spin flip on the normalized Larmor frequency is investigated numerically for different parameters of the model. It is shown that the position of the main resonance is independent of the deformation of the field; only the width of the resonance peak changes upon deformation. The odd parametric (’multiphoton) resonance transitions are investigated. The static magnetization induced by the harmonized field is considered. This study may find application in the analysis of interference experiments, for refining the designs of magnetic spectrometers, and for controlling qubits.
Electromagnetic absorption of a bimetallic spherical particle
Authors: Zavitaev E. V.
Published: August 2005

The cross section for absorption of electromagnetic radiation in a bimetallic spherical particle are calculated. The general case of arbitrary values of the ratio of the radius of the core to the radius of the particle is considered. The boundary conditions adopted are the condition of diffuse reflection of electrons from the internal and external surfaces of the metallic layer of the particle. The limiting cases are considered and the results are discussed.
Incommensurate structures on the surface of an elastic half space
Authors: Kovalev A. S. , Sokolova E. S.
Published: August 2005

A static incommensurate structure on the surface of an elastic half space covered by a monolayer of another substance with different stiffness and a different equilibrium interatomic spacing is considered, and a system of one-dimensional nonlinear integro-differential equations describing such a structure is derived. In the case of an absolutely rigid monolayer (the opposite case from that usually considered in the Frenkel–Kontorova model: the limit of a soft monolayer on an absolutely rigid substrate) some new classes of periodic solutions of the Peierls equation for incommensurate surface structures are found which differ substantially from those known previously. An approximate description of the structure of nonuniform surface states is obtained for a stiff monolayer with a low compliance on a soft half space and for a soft monolayer on a stiff half space with a low compliance, i.e., the approximate dependence of the period of these structures on the incommensurability parameter (the difference of the lattice periods of the half space and monolayer) and their stiffnesses is found. The results obtained permit a qualitative description of the transformation of incommensurate surface structures in the whole range of the aforementioned parameters.
Compressive strength measurements in aluminum for shock compression over the stress range of 4–22GPa
Authors: Huang H. , Asay J. R.
Published: August 2005

Measurements of the high-pressure compressive strength are presented for several aluminum alloys shocked to 22GPa. Five well-characterized aluminum materials were studied, including 6061 alloy with three average grain sizes (50, 30, and <5μm), pure aluminum 1060 (99.5% Al) with a 180-μm grain size, and ultrapure aluminum (99.9998% Al) with a 300-μm grain size. The purpose of these experiments was to investigate deformation mechanisms responsible for the apparently anomalous quasielastic recompression previously observed and to determine how the shock-induced yield strength varies with initial properties. The yield strength was estimated using combined reshock and release techniques previously developed. These results show that quasielastic recompression occurs for all materials investigated and is independent of grain size and impurity level. The shear stress and the shear strength at the shocked state were estimated from the reshock and release wave profiles. These results are consistent with previous investigations and suggest that the shear stress at the Hugoniot state is less than the yield strength. This is thought responsible for the observed quasielastic recompression. The present data, together with other reported measurements, illustrate that the yield strength of aluminum increases with applied shock stress to 90GPa. The Steinberg-Guinan strength model [Steinberg, Cochran, and Guinan, J. Appl. Phys. 51, 1498 (1980)] was used to describe these data and was found to represent the overall data trend with increasing stress, but is not an accurate representation. The collective data suggest that the increase in strength at shock states, ΔY(ΔY=Yyield−YHEL), increases with applied stress and plastic strain. A strength model was developed to describe this increase, which fits the data accurately to 55GPa and reveals that ΔY increases with shock stress in three distinct regions. It also strongly indicates that metallurgical properties, such as impurities and grain size, influence the ambient yield strength, but not the change in strength, which appears to be controlled by the shock-deformed aluminum matrix and possibly grain boundaries.
Investigation on (Al0.7Ga0.3)0.5In0.5P∕(Al0.3Ga0.7)0.5In0.5P multi-quantum-barrier superlattice using cross-sectional scanning tunneling microscopy
Authors: Teng K. S. , Cobley R. J. , Brown M. R. , Wilks S. P. , Dunstan P. R.
Published: August 2005

Cross-sectional scanning tunneling microscopy (XSTM) is used to study a multi-quantum-barrier (MQB) structure consisting of (Al0.7Ga0.3)0.5In0.5P∕(Al0.3Ga0.7)0.5In0.5P semiconductor superlattice for use in AlGaInP laser devices. Quantitative analysis of the MQB was made difficult by poor image contrast due to the intrinsic small band offset of 80meV between adjacent layers in the large band-gap semiconductor superlattices. This is in addition to the presence of cleavage-induced monatomic steps at the clean cleaved (110) surface as they effectively mask the weak electronic features of the superlattice. To overcome these problems, the image contrast was enhanced by the choice of tunneling conditions, in particular, reducing the tip-sample separation and the origin of this mechanism is believed to be associated with tip-induced band bending. In addition, the use of arithmetic manipulation of images to eliminate physical features such as step defects on the cleaved surface is also reported. This allowed quantitative analysis to be performed on the superlattice. Results from the XSTM studies showed that the (Al0.7Ga0.3)0.5In0.5P∕(Al0.3Ga0.7)0.5In0.5P superlattices have very limited interdiffusion. This is in stark contrast to other MQB candidates involving Al0.5In0.5P∕Ga0.5In0.5P and Al0.5In0.5P∕(Al0.3Ga0.7)0.5In0.5P superlattices which revealed extensive broadening of the well in the superlattices as previously studied by the authors.
Study of the sputtered Cu atoms and Cu+ ions in a hollow cathode glow discharge using a hybrid model
Authors: Baguer N. , Bogaerts A.
Published: August 2005

The role of the Cu atoms sputtered from the cathode material in a cylindrical hollow cathode discharge (HCD) and the corresponding Cu+ ions are studied with a self-consistent model based on the principle of Monte Carlo (MC) and fluid simulations. In order to obtain a more realistic view of the discharge processes, this model is coupled with other submodels, which describe the behavior of electrons, fast Ar atoms, Ar+ ions, and Ar metastable atoms, also based on the principles of MC and fluid simulations. Typical results are, among others, the thermalization profile of the Cu atoms, the fast Cu atom, the thermal Cu atom and Cu+ ion fluxes and densities, and the energy distribution of the Cu+ ions. It was found that the contribution of the Ar+ ions to the sputtering was the most significant, followed by the fast Ar atoms. At the cathode bottom, there was no net sputtered flux but a net amount of redeposition. Throughout the discharge volume, at all the conditions investigated, the largest concentration of Cu atoms was found in the lower half of the HCD, close to the bottom. Penning ionization was found the main ionization mechanism for the Cu atoms. The ionization degree of copper atoms was found to be in the same order as for the argon atoms (10−4).
Mechanisms of sound generation during flash lamp operation
Authors: Kitagawa Tetsuya , Ikeuchi Mitsuru , Morimoto Yukihiro , Oda Fumihiko
Published: August 2005

Changes in sound pressure wave forms by operating flash lamps were studied. In the experiments, two types of lamp were prepared, one of which emitted vacuum ultraviolet (VUV) light and the other did not. We investigated the position of the sound pressure origination, the frequency component, and the relation between the degree of sound pressure and the surrounding atmosphere. It was found that there are two kinds of frequency components in the exploding sound, due to the significant sound pressure. One is an audible frequency component originated from light radiated from the lamp, and the other is the higher frequency component of a nonaudible sound, caused by the mechanical vibration of the flash lamp tube. The audible sound was generated as follows: Oxygen and water vapor absorb VUV light, water vapor absorbs infrared light which is a part of the spectrum of the flash lamp, and heating occurs. Consequently air rapidly expands and generates sound pressure. We propose that sound pressure in operating flash lamps could be strongly reduced by controlling the surrounding atmosphere.
Coherent thermal emission from one-dimensional photonic crystals
Authors: Lee B. J. , Fu C. J. , Zhang Z. M.
Published: August 2005

Coherent thermal emission from surface relief gratings holds promise for spectral and directional control of thermal radiation but is limited to transverse magnetic waves, which can excite surface plasmon or phonon polaritons in the grating structure. We show in this letter that a coherent thermal source can be constructed with a thin polar material coated on a one-dimensional photonic crystal. The excitation of surface waves at the interface of the coated layer and the photonic crystal results in highly spectral and directional emission in the infrared for both the transverse electric wave and the transverse magnetic wave.
Growth of epitaxial SmCo5 films on Cr∕MgO(100)
Authors: Singh A. , Neu V. , Tamm R. , Rao K. Subba , Fähler S. , Skrotzki W. , Schultz L. , Holzapfel B.
Published: August 2005

Although the hard magnetic SmCo5 phase has very attractive and well-known intrinsic magnetic properties, it has not been grown as an epitaxial thin film, so far. This letter reports the epitaxial growth of SmCo5 films by pulsed-laser deposition on Cr(100) buffered MgO(100) single-crystal substrates. The phase purity, crystal structure, epitaxial relation to the substrate, and magnetic properties have been determined by careful energy-dispersive x-ray analysis, pole figure measurements, transmission electron microscopy, and vibrating sample magnetometry. Compared to the formerly studied Sm2Co7 films, the preparation of the SmCo5 phase improves the remanent magnetization by 38%.
Tantalum films with well-controlled roughness grown by oblique incidence deposition
Authors: Rechendorff K. , Hovgaard M. B. , Chevallier J. , Foss M. , Besenbacher F.
Published: August 2005

We have investigated how tantalum films with well-controlled surface roughness can be grown by e-gun evaporation with oblique angle of incidence between the evaporation flux and the surface normal. Due to a more pronounced shadowing effect the root-mean-square roughness increases from about 2 to 33 nm as grazing incidence is approached. The exponent, characterizing the scaling of the root-mean-square roughness with length scale (α), varies from 0.75 to 0.93, and a clear correlation is found between the angle of incidence and root-mean-square roughness.
Quasi-aligned single-crystalline GaN nanowire arrays
Authors: Liu Baodan , Bando Yoshio , Tang Chengchun , Xu Fangfang , Golberg Dmitri
Published: August 2005

Quasi-aligned GaN nanowire arrays have been fabricated via a thermal evaporation of the starting reactants Ga2O3∕GaN. The GaN nanowires have uniform diameters of ∼300nm, lengths up to tens of micrometers and possess a sharp six-fold symmetrical pyramidlike tip. High-resolution transmission electron microscopy (TEM) analysis indicated that majority of GaN nanowires have a preferential growth direction along the [0001] direction. Room-temperature field-emission measurement showed that the as-synthesized GaN nanowire arrays have a lower turn-on field of 7.0V/μm. It is believed that both the sharp tips and rough surface of GaN nanowires contribute to the excellent electron emission behavior.
Suppression of DC bias stress-induced degradation of organic field-effect transistors using postannealing effects
Authors: Sekitani Tsuyoshi , Iba Shingo , Kato Yusaku , Noguchi Yoshiaki , Someya Takao , Sakurai Takayasu
Published: August 2005

We fabricate pentacene field-effect transistors (FETs) showing a very small degradation in performance under a continuous DC bias stress. Pentacene FETs are manufactured on polyimide films with polyimide gate dielectric layers, and then encapsulated by poly-chloro-para-xylylene passivation layers, resulting in very flexible and heat-resistant devices. When such devices are annealed at 140°C for 12h in a nitrogen environment, the change in their source-drain current is 3±1% even after the application of continuous DC voltage biases of VDS=VGS=−40V for 11h. Furthermore, their mobility is increased by postannealing effects from 0.27cm2∕Vsto0.36cm2∕Vs and their on/off ratio is also increased from 103 to 106.
Nanowell surface enhanced Raman scattering arrays fabricated by soft-lithography for label-free biomolecular detections in integrated microfluidics
Authors: Liu Gang L. , Lee Luke P.
Published: August 2005

We describe a low-cost, ultrasensitive surface-enhanced Raman scattering (SERS) substrate in microfluidic biochips fabricated by soft lithography. A batch nanofabrication method is developed to create nanopillars structures on a silicon wafer as a master copy of molding, then the complementary nanowells structures on polydimethylsiloxane (PDMS) are created by soft lithography. The selective deposition of Ag thin film on the nanowells is applied to create SERS active sites before the integration with a glass-based microfluidic chip which functions as a sample delivery device and a transparent optical window for SERS spectroscopic imaging. Detections of Rhodamine 6G and adenosine SERS spectra are accomplished by using a 785nm laser with 300μW excitation power. The Raman scattering signal enhancement on the nanowell-based Ag SERS substrate is more than 107 times higher than the control sample (i.e. the smooth Ag layer on PDMS). Fabrication of ultrasensitive nanowell SERS substrate by economical and repeatable soft lithography method can contribute to the future microdevices for high throughput screening of functional genomics, proteomics, and cellular activities.
Functional Remobilization Evaluation of the Paralyzed Vocal Cord by End‐to‐Side Neurorrhaphy in Rats
Authors: Liu Hong‐Jian , Dong Ming‐Min , Chi Fang‐Lu
Published: August 2005

Objective: To investigate the value of end‐to‐side neurorrhaphy to treat vocal cord paralysis.

Study Design: A prospective study evaluating the effects of end‐to‐side neurorrhaphy to treat vocal cord paralysis by means of fiberoptic laryngoscopy and nerve electromyography.

Methods: Thirty Sprague‐Dawley rats were divided into experimental group 1, experimental group 2, and a control group randomly. Right recurrent laryngeal nerve (RLN) was incised, and the distal end of the RLN was anastomosed to the right phrenic nerve by end‐to‐side neurorrhaphy in experimental group 1 or by end‐to‐end nerve anastomosis in experimental group 2, respectively. The adductor nerve branch of the right RLN was incised and anastomosed to the proximal end of the right ansa cervicalis nerve by end‐to‐end nerve anastomosis. Fiberoptic laryngoscopy and nerve electromyography were used to examine the vocal cord movement and nerve regeneration.

Results: Three months after operation, this effect of end‐to‐side neurorrhaphy created a significant difference compared with the end‐to‐end nerve anastomosis (P < .05). The end‐to‐side neurorrhaphy did not lead to vocal cord movement compared with end‐to‐end nerve anastomosis.

Conclusion: Vocal cord paralysis cannot be treated by this microsurgical technique.
Prognostic Variables and Calcitonin in Medullary Thyroid Cancer
Authors: Clark Jonathan R. , Fridman Tauba R. , Odell Michael J. , Brierley James , Walfish Paul G. , Freeman Jeremy L.
Published: August 2005

Objectives/Hypothesis: Medullary thyroid cancer (MTC) is a nonepithelial, neuroendocrine tumor with a more aggressive clinical behavior than differentiated thyroid cancer. The purpose of the study was to review a single institution's experience with MCT since 1969.

Study Design: Retrospective cohort study.

Methods: A retrospective review of 30 patients treated for MTC at a tertiary care referral center between 1969 and 2000. There were 17 female and 13 male patients, median age at presentation was 38 years, and median follow‐up for survivors was 12.4 years.

Results: Seventy percent of patients had sporadic MTC, 6.7% had familial MTC, 16.7% had multiple endocrine neoplasia syndrome type IIA, and 6.7% had multiple endocrine neoplasia syndrome type IIB. The cumulative overall survival rates at 5, 10, and 20 years were 97%, 88%, and 84%, respectively; disease‐free survival rates were 97%, 74%, and 29%, respectively. Advanced tumor stage (P = .014) and multiple endocrine neoplasia syndrome type IIB predicted decreased disease‐specific survival. Variables affecting disease‐free survival were post‐thyroidectomy calcitonin level (P = .001), vascular invasion (P = .005), perineural invasion (P = .010), extrathyroidal extension (P < .001), and the presence of nodal metastases (P = .001). Locoregional control rates were 83% at 5 years and 70% at 10 years. Vascular invasion (P = .004), extrathyroidal extension (P = .008), and post‐thyroidectomy basal calcitonin level (P = .003) predicted locoregional failure. Many patients in the series experienced prolonged survival despite elevated calcitonin levels.

Conclusion: Long‐term disease‐free survival is uncommon in MTC, but the study data indicate that the majority of patients with MTC live for prolonged periods, despite biochemical evidence of persistent disease. Adverse pathological features such as extrathyroidal extension and vascular and perineural invasion were predictors of disease recurrence. The use of serum markers in the follow‐up of patients with MTC must be interpreted within the clinical context.
Endolymphatic Sac Decompression as a Treatment for Meniere's Disease
Authors: Durland William F. , Pyle G Mark , Connor Nadine P.
Published: August 2005

Objectives/Hypothesis: Endolymphatic sac decompression is a surgical treatment option for patients with medically intractable Meniere's disease. However, effectiveness is debated because published data show great variability. Outcome‐based research studies are useful in incorporating the patient's perspective on the success of treatment. To further assess effectiveness of endolymphatic sac decompression, we performed a prospective study to examine both symptom‐specific and general health outcomes.

Study Design: Prospective, observational outcome study.

Methods: Nineteen patients with endolymphatic sac decompression responded to symptom‐specific questionnaires and the Medical Outcomes Short‐Form 36 Health Survey (SF‐36) before and after surgery. Follow‐up ranged from 6 to 58 months with a mean duration of 50 months.

Results: Overall measures of physical health were significantly improved following endolymphatic sac decompression (P = .04), whereas overall measures of mental health were unchanged (P = .74). Role Physical and Social Functioning scores were significantly improved following endolymphatic sac decompression (P = .04 and P = .03, respectively). Study patients scored significantly lower (P < .05) than SF‐36 normative data in 6 of 10 categories before endolymphatic sac decompression but patient scores were not significantly different from normal scores in all but one category (General Health) following endolymphatic sac decompression. The mean number of vertigo episodes was significantly reduced from an average of 8.3 times per month to an average of 2.6 times per month following endolymphatic sac decompression (P = .006). Ninety‐five percent of patients (18 of 19 patients) reported improvement in symptoms (frequency, duration, or intensity) of vertigo and 37% (7 of 19 patients) reported complete resolution of vertigo.

Conclusion: Endolymphatic sac decompression significantly improved perception of physical health, as well as symptom‐specific outcomes, in patients with medically intractable Meniere's disease.
Angiofibrolipoma of the Ear Canal
Authors: Jacob Abraham , Kneile Jeffrey , Welling D Bradley
Published: August 2005

Objectives/Hypothesis: Described is the first reported case of an angiofibrolipoma of the ear canal in a patient who presented with right‐sided conductive hearing loss and a medial canal stenosis.

Study Design: Case report.

Results/Conclusion: This variant of lipoma contains mature adipocytes, blood vessels, and dense collagenous tissue. The physical examination can be misleading, and the diagnosis requires histopathological examination. The patient was treated with complete surgical excision, tympanoplasty, canalplasty, and skin grafting to the external auditory canal.

His pure‐tone average improved from 37 to 11 dB, and his air‐bone gap was closed completely.

The lipoma has not recurred in the 6‐month period following surgery.
Cochlear Implantation in Deaf Infants
Authors: Miyamoto Richard T. , Houston Derek M. , Bergeson Tonya
Published: August 2005

Objectives: With the application of universal newborn hearing screening programs, a large pool of newly identified deaf infants has been identified. The benefits of early intervention with cochlear implants (CI) is being explored. Mounting evidence suggests that age at implantation is a strong predictor of language outcomes. However, new behavioral procedures are needed to measure speech and language skills during infancy. Also, procedures are needed to analyze the speech input to young CI recipients.

Study Design: Cohort‐sequential.

Methods: Thirteen infants with profound hearing loss who were implanted between the ages of 6 to 12 months of age participated in this study. Eight participated in two new behavioral methodologies: 1) the visual habituation procedure to assess their discrimination of speech sounds; 2) the preferential looking paradigm to assess their ability to learn associations between speech sounds and objects. Older implanted infants and normal‐hearing infants were also tested for comparison. The pitch of mothers' speech to infants was analyzed.

Results: Patterns of looking times for the very early implanted infants were similar to those of normal hearing infants. Mothers' speech to infants with CIs was similar in pitch to normal‐hearing infants who had the same duration of experience with sounds.

Conclusions: No surgical or anesthetic complications occurred in this group of infants, and the pattern of listening skill development mirrors that seen in normal‐hearing infants. Mothers adjust their speech to suit the listening experience of their infants.
Molecular Prognosticators and Genomic Instability in Papillary Thyroid Cancer
Authors: Rigual Nestor R. , Anderson Garth R. , Loree Thom R. , Wiseman Sam , Alrawi Sadir , Stoler Daniel L.
Published: August 2005

Objectives/Hypothesis: Tumor progression has been attributed to the accumulation of DNA damage concurrent with selection of advantageous mutations; this DNA damage may result from failure to maintain genomic integrity or from susceptibility to carcinogens. Glutathione S‐transferases (GSTs), enzymes that metabolize many carcinogens, may play a role in preserving genome integrity. The objectives of this study are to assess the relationship of GST genotypes with prognosis, clinicopathologic parameters, and genomic instability in papillary thyroid cancer.

Study Design: Prospective analysis.

Methods: GSTM1 and GSTT1 genotypes of 35 matched normal and papillary thyroid cancer specimens were determined by polymerase chain reaction (PCR) using primers specific for the coding sequences of each gene. Genomic instability was measured by intersimple sequence repeat PCR for each tumor/normal pair and compared with the GAMES prognostic scoring system and clinicopathologic parameters including age, extrathyroidal extension, tumor grade, size, stage metastasis, sex, and smoking history.

Results: GSTM1 and GSTT1 null genotypes were found in the normal tissues of 46% and 45%, respectively. No gene losses were detected in the tumor specimens. A significant association between the GSTM1 null genotype and increased risk of recurrence and death was observed. Elevated GII correlated with smoking and tumor stage but not with GST genotype.

Conclusion: The association of GSTM1 null genotype with intermediate and high risk GAMES categories suggests that GSTM1 provides some protection against disease progression. However, this protection does not confer resistance to disease onset. GST genotyping may be a useful adjunct prognosticator with GAMES.
Long‐Term Clinical, Audiologic, and Radiologic Outcomes in Palate Cleft Children Treated with Early Tympanostomy for Otitis Media with Effusion: A Controlled Prospective Study
Authors: Valtonen Hannu , Dietz Aarno , Qvarnberg Yrjö
Published: August 2005

Objectives: The role of tympanostomy in the treatment of otitis media with effusion (OME) in children with palate cleft with regard to the otologic and audiologic outcome is controversial. Little is known about the development of the mastoid air cell system (MACS) in these children.

Study Design: Controlled, prospective.

Methods: All children born in the hospital district area of the Central Hospital of Central Finland during the years 1983 to 1993 with palate cleft were reviewed at the age of 6 months. A total of 39 patients were followed up for 6 years after primary tympanostomy. Otologic and audiologic data were collected, and the MACS size was planimetrically measured. The control group consisted of age‐matched children without palate cleft suffering from OME and were identically reviewed.

Results: The otologic outcome was similar in the study group, 64.1%, and among the controls, 60.6% were healed. There were no serious otologic complications in the study group. The audiologic outcome was also similar, with a mean pure‐tone average (0.5–2 kHz) of 10.5 dB and 10.9 dB for the corresponding groups. The initial size and growth of the MACS did not significantly differ between the groups.

Conclusions: The prognosis of children with palate cleft treated with early tympanostomy is favorable and does not differ from children without palate cleft. Active treatment ensures normal hearing during the critical years of language, speech, and cognitive development and maintains the development of an aerated mastoid. We believe that early tympanostomy is the treatment of choice of OME in palate cleft children.
Constraints on plastic responses to climate variation in red deer
Authors: Nussey Daniel H , Clutton-Brock Tim H , Albon Steve D , Pemberton Josephine , Kruuk Loeske E.B
Published: August 2005

Influences of climate on life history traits in natural populations are well documented. However, the implications of between-individual variation in phenotypic plasticity underlying observed trait–environment relationships are rarely considered due to the large, long-term datasets required for such analysis. Studies typically present correlations of annual trait means with climate or assume that individual phenotypic responses are constant. Here, we examine this additional level of variation and show that, in a red deer population on the Isle of Rum, Scotland, changes in climate generate changes in phenotype only amongst individuals who have experienced favourable ecological conditions. Examination of relationships between offspring birth weight and spring temperature within the lifetimes of individual females revealed that the tendency to respond to climate declined as the population density experienced early in life increased. The presence of such systematic variation in individual plasticity is rarely documented in the wild, and has important implications for our understanding of the environmental dependencies of traits under varying ecological conditions.
Benefits of organic farming to biodiversity vary among taxa
Authors: Fuller R.J , Norton L.R , Feber R.E , Johnson P.J , Chamberlain D.E , Joys A.C , Mathews F , Stuart R.C , Townsend M.C , Manley W.J , Wolfe M.S , Macdonald D.W , Firbank L.G
Published: August 2005

Habitat and biodiversity differences between matched pairs of organic and non-organic farms containing cereal crops in lowland England were assessed by a large-scale study of plants, invertebrates, birds and bats. Habitat extent, composition and management on organic farms was likely to favour higher levels of biodiversity and indeed organic farms tended to support higher numbers of species and overall abundance across most taxa. However, the magnitude of the response varied; plants showed larger and more consistent responses than other taxa. Variation in response across taxa may be partly a consequence of the small size and isolated context of many organic farms. Extension of organic farming could contribute to the restoration of biodiversity in agricultural landscapes.