bluuebunny/crossref_metadata_2025 huggingface dataset:
Diet and Exercise Interventions Reduce Intrahepatic Fat Content and Improve Insulin Sensitivity in Obese Older Adults
Authors: Shah Krupa , Stufflebam Abby , Hilton Tiffany N. , Sinacore David R. , Klein Samuel , Villareal Dennis T.
Published: April 2009

Both obesity and aging increase intrahepatic fat (IHF) content, which leads to nonalcoholic fatty liver disease (NAFLD) and metabolic abnormalities such as insulin resistance. We evaluated the effects of diet and diet in conjunction with exercise on IHF content and associated metabolic abnormalities in obese older adults. Eighteen obese (BMI ≥30 kg/m2) older (≥65 years old) adults completed a 6‐month clinical trial. Participants were randomized to diet (D group; n = 9) or diet + exercise (D+E group; n = 9). Primary outcome was IHF quantified by magnetic resonance spectroscopy (MRS). Secondary outcomes included insulin sensitivity (assessed by oral glucose tolerance), body composition (assessed by dual‐energy X‐ray absorptiometry), physical function (VO2peak and strength), glucose, lipids, and blood pressure (BP). Body weight (D: −9 ± 1%, D+E: −10 ± 2%, both P < 0.05) and fat mass (D: −13 ± 3%, D+E −16 ± 3%, both P < 0.05) decreased in both groups but there was no difference between groups. IHF decreased to a similar extent in both groups (D: −46 ± 11%, D+E: −45 ± 8%, both P < 0.05), which was accompanied by comparable improvements in insulin sensitivity (D: 66 ± 25%, D+E: 68 ± 28%, both P < 0.05). The relative decreases in IHF correlated directly with relative increases in insulin sensitivity index (ISI) (r = −0.52; P < 0.05). Improvements in VO2peak, strength, plasma triglyceride (TG), and low‐density lipoprotein–cholesterol concentration, and diastolic BP occurred in the D+E group (all P < 0.05) but not in the D group. Diet with or without exercise results in significant decreases in IHF content accompanied by considerable improvements in insulin sensitivity in obese older adults. The addition of exercise to diet therapy improves physical function and other obesity‐ and aging‐related metabolic abnormalities.
Trends and Disparities in Provider Diagnosis of Overweight Analysis of NHANES 1999–2004
Authors: Davis Nichola J. , Wildman Rachel P. , Forbes Bernice F. , Schechter Clyde B.
Published: April 2009

Rates of overweight and obesity are disproportionately high within minority populations. This study examined the trends in provider diagnosis of overweight from 1999 to 2004 and examined whether there were differences in provider diagnosis based on race/ethnicity. We examined data from 4,071 adults with BMI ≥30 who participated in the National Health and Nutrition Examination Surveys (NHANES) (1999–2004). Provider diagnosis was determined by self‐report. From 1999 to 2004, the provider diagnosis of overweight decreased from 71 to 64% (P = 0.003). After controlling for potential confounders, non‐Hispanic blacks and Mexican Americans were less likely to report a provider diagnosis of overweight compared to non‐Hispanic whites. Odds ratio (OR) (95% confidence interval (CI)) for non‐Hispanic blacks was 0.6 (95% CI, 0.4–0.8) and for Mexican Americans was 0.7 (95% CI, 0.4–1.0) compared to non‐Hispanic whites. Reasons for this disparity warrant further investigation.
Associations Between Perceived Weight Discrimination and the Prevalence of Psychiatric Disorders in the General Population
Authors: Hatzenbuehler Mark L. , Keyes Katherine M. , Hasin Deborah S.
Published: April 2009

Despite the increased prevalence of weight discrimination, few studies have examined the association between perceived weight discrimination and the prevalence of current psychiatric disorders in the general population. This study utilized a subsample of overweight and obese individuals (N = 22,231) from Wave 2 of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), a cross‐sectional nationally representative study of noninstitutionalized US adults. Perceived weight discrimination is associated with substantial psychiatric morbidity and comorbidity. These results remained significant after adjusting for a potential confound, perceived stress. Moreover, social support did not buffer against the adverse effects of perceived weight discrimination on mental health. Controlling for BMI did not diminish the associations, indicating that perceived weight discrimination is potentially harmful to mental health regardless of weight. These results highlight the urgent need for a multifaceted approach to address this important public health issue, including interventions to assist overweight individuals in coping with the mental health sequelae of perceived weight discrimination.
Ethnic Differences in Subcutaneous Adiposity and Waist Girth in Children and Adolescents
Authors: Sisson Susan B. , Katzmarzyk Peter T. , Srinivasan Sathanur R. , Chen Wei , Freedman David S. , Bouchard Claude , Berenson Gerald S.
Published: April 2009

The purpose of this study was to examine ethnic differences in adiposity as measured by sum of skinfolds (SKF) and waist circumference (WC) in children and adolescents, after statistical adjustment for the BMI and age. A cross sectional sample of 3,218 (55% white, 49% male) children and adolescents aged 5–18 years who participated in the Bogalusa Heart Study (1992–1994) were included in these analyses. Sex‐specific ANOVAs, adjusted for BMI and age, for each 2‐year age group compared measures of adiposity (SKF and WC) between ethnic groups. No significant differences in the proportions of children and adolescents who were overweight and obese by ethnicity or sex were found. Mean SKF in normal weight (P < 0.0001) and overweight (P < 0.0001) categories was higher for white than black children of both sexes. Across most age categories, white boys and girls had significantly higher SKF than black boys and girls, respectively (P ≤ 0.05). Across most age categories, white boys had significantly higher WC than black boys (P ≤ 0.05) with no difference in the girls, when adjusted for BMI and age. Measures of adiposity in childhood and adolescence were significantly higher in white children compared to black children, when adjusted for BMI and age. Throughout childhood and adolescence, white boys and girls had higher SKF and white boys had higher WC. Differences in adiposity between ethnic groups should be considered in disease risk assessment and stratification as they are observed even for a given BMI level.
Analyte chemisorption and sensing on n- and p-channel copper phthalocyanine thin-film transistors
Authors: Yang Richard D. , Park Jeongwon , Colesniuc Corneliu N. , Schuller Ivan K. , Royer James E. , Trogler William C. , Kummel Andrew C.
Published: April 2009

Chemical sensing properties of phthalocyanine thin-film transistors have been investigated using nearly identical n- and p-channel devices. P-type copper phthalocyanine (CuPc) has been modified with fluorine groups to convert the charge carriers from holes to electrons. The sensor responses to the tight binding analyte dimethyl methylphosphonate (DMMP) and weak binding analyte methanol (MeOH) were compared in air and N2. The results suggest that the sensor response involves counterdoping of pre-adsorbed oxygen (O2). A linear dependence of chemical response to DMMP concentration was observed in both n- and p- type devices. For DMMP, there is a factor of 2.5 difference in the chemical sensitivity between n- and p-channel CuPc thin-film transistors, even though it has similar binding strength to n- and p-type CuPc molecules as indicated by the desorption times. The effect is attributed to the difference in the analyte perturbation of electron and hole trap energies in n- and p-type materials.
An analytical model for the wettability switching characteristic of a nanostructured thermoresponsive surface
Authors: Londe Ghanashyam , Chunder Anindarupa , Zhai Lei , Cho Hyoung J.
Published: April 2009

The applications of thermoresponsive surfaces require the development of a rigorous mathematical treatment for these surfaces to understand and improve their behavior. We propose an analytical model to describe the transfer characteristics (variation in contact angle versus temperature) of a unique nanostructured thermosensitive surface, consisting of silica nanoparticles and a hydrophilic/hydrophobic thermoresponsive polymer, poly(N-isopropylacrylamide). Three different thermo-sensitive platforms were fabricated and the contact angle change of a water droplet on the surface with varying surface temperature was analytically modeled.
Spatial order prevails over memory in boosting cooperation in the iterated prisoner’s dilemma
Authors: Alonso-Sanz Ramón
Published: April 2009

This paper presents some results on a spatial version of the iterated prisoner’s dilemma in which every player imitates in any iteration the optimal strategy of its neighbors. Neighbors are defined with different degrees of random variation (initial rewiring) based on a square lattice, and optimal is defined with different degrees of memory, ranging from only the single preceding iteration up to all preceding iterations. It is concluded that memory notably stimulates cooperation in the iterated prisoner’s dilemma played in ordered lattices, but it is unable to boost cooperation as the wiring network becomes highly disordered.
Enhancement of conductivity and transmittance of ZnO films by post hydrogen plasma treatment
Authors: Cai P. F. , You J. B. , Zhang X. W. , Dong J. J. , Yang X. L. , Yin Z. G. , Chen N. F.
Published: April 2009

We studied the effects of hydrogen plasma treatment on the electrical and optical properties of ZnO films deposited by radio frequency magnetron sputtering. It is found that the ZnO:H film is highly transparent with the average transmittance of 92% in the visible range. Both carrier concentration and mobility are increased after hydrogen plasma treatment, correspondingly, the resistivity of the ZnO:H films achieves the order of 10−3 Ω cm. We suggest that the incorporated hydrogen not only passivates most of the defects and/or acceptors present, but also introduces shallow donor states such as the VO-H complex and the interstitial hydrogen Hi. Moreover, the annealing data indicate that Hi is unstable in ZnO, while the VO-H complex remains stable on the whole at 400 °C, and the latter diffuses out when the annealing temperature increases to 500 °C. These results make ZnO:H more attractive for future applications as transparent conducting electrodes.
Feasibility study of high-resolution coherent diffraction microscopy using synchrotron x rays focused by Kirkpatrick–Baez mirrors
Authors: Takahashi Yukio , Nishino Yoshinori , Mimura Hidekazu , Tsutsumi Ryosuke , Kubo Hideto , Ishikawa Tetsuya , Yamauchi Kazuto
Published: April 2009

High-flux coherent x rays are necessary for the improvement of the spatial resolution in coherent x-ray diffraction microscopy (CXDM). In this study, high-resolution CXDM using Kirkpatrick–Baez (KB) mirrors is proposed, and the mirrors are designed for experiments of the transmission scheme at SPring-8. Both the photon density and spatial coherence of synchrotron x rays focused by the KB mirrors are investigated by wave optical simulation. The KB mirrors can produce nearly diffraction-limited two-dimensional focusing x rays of ∼1μm in size at 8keV. When the sample size is less than ∼1μm, the sample can be illuminated with full coherent x rays by adjusting the cross-slit size set between the source and the mirrors. From the estimated photon density at the sample position, the feasibility of CXDM with a sub-1-nm spatial resolution is suggested. The present ultraprecise figuring process enables us to fabricate mirrors for carrying out high-resolution CXDM experiments.
Electrical characterization and modeling of the Au/CaF2/nSi(111) structures with high-quality tunnel-thin fluoride layer
Authors: Vexler M. I. , Sokolov N. S. , Suturin S. M. , Banshchikov A. G. , Tyaginov S. E. , Grasser T.
Published: April 2009

Au / CaF 2 / n Si ( 111 ) structures with 4–5 monolayers of epitaxial fluoride are fabricated and electrically tested. The leakage current in these structures was substantially smaller than in similar samples reported previously. Simulations adopting a Franz-type dispersion relation with Franz mass of mF∼1.2m0 for carriers in the forbidden band of CaF2 reproduced the measured current-voltage curves quite satisfactorily. Roughly, these curves could also be reproduced using the parabolic dispersion law with the electron mass of me=1.0m0, which is a material constant rather than a fitting parameter. Experimental facts and their comparison to modeling results allow qualification of the crystalline quality of fabricated structures as sufficient for device applications.
Thermal emittance and response time measurements of a GaN photocathode
Authors: Bazarov Ivan V. , Dunham Bruce M. , Liu Xianghong , Virgo Matt , Dabiran Amir M. , Hannon Fay , Sayed Hisham
Published: April 2009

We present the measurements of thermal emittance and response time for a GaN photocathode illuminated with 5 ps pulses at 260 nm wavelength. The thermal emittance was measured downstream of a 100 kV dc gun using a solenoid scan with a wire scanner and a beam viewscreen and was found to be 1.35±0.11 mm mrad normalized rms emittance per 1 mm rms of illuminated spot size. The response time of the photoemitted electrons was evaluated using a deflecting mode rf cavity synchronized to the laser pulses and was found to be prompt within the time resolution capability of our setup.
CoSi
2
-coated Si nanocrystal memory
Authors: Li Bei , Liu Jianlin
Published: April 2009

CoSi 2 -coated Si nanocrystals were fabricated as the floating gates for nonvolatile memory applications to improve the Si nanocrystal memory performance in terms of programming/erasing efficiency and retention time. Discrete CoSi2-coated Si nanocrystals were formed by silicidation of Si nanocrystals on SiO2 and subsequent selective etching of unreacted metal cobalt over silicide. Metal-oxide-semiconductor field-effect transistor memories with CoSi2-coated Si nanocrystals and reference Si nanocrystals as floating gates were fabricated and characterized. Longer retention, larger charging capability and faster programming/erasing were observed in CoSi2-coated Si nanocrystal memory compared with Si nanocrystal memory. CoSi2 Fermi-level pinning of defect levels plays important role in the device performance enhancement.
Sizing of partially closed surface-breaking microcracks with broadband Rayleigh waves
Authors: Lomonosov Alexey M. , Grigoriev Peter V. , Hess Peter
Published: April 2009

Sizing of cracks in the range of tens of micrometers by laser-generated surface acoustic wave (SAW) pulses with a bandwidth of up to 200 MHz is reported. The radius of a semicircular surface-breaking crack was evaluated using two methods, one based on the experimentally measured reflection coefficient and the other on the frequency dependence of the phase lag of the transmitted wave. These quantities were also simulated numerically by means of the finite differences method and fitted to the experimental ones by varying the assumed size of the crack. In both cases the interaction between crack faces was taken into account by an effective interfacial stiffness parameter and the crack sizes obtained acoustically were compared with those measured by optical microscopy. Nondestructive evaluation was extended to the characterization of real microcracks in the range of tens of micrometers with the laser-based pump-probe technique. The microcracks studied were generated in fused silica by strongly nonlinear SAW pulses with shocks in a separate experiment.
Bonding, vibrational, and electrical characteristics of CdS nanostructures embedded in polyvinyl alcohol matrix
Authors: Mondal S. P. , Dhar A. , Ray S. K. , Chakraborty A. K.
Published: April 2009

CdS nanocomposites have been grown in polyvinyl alcohol matrix by a chemical synthesis process. The transmission electron micrographs of nanocomposites synthesized at 70–90 °C temperature showed the growth of needlelike and junctionlike nanostructures. X-ray photoelectron spectroscopy analysis revealed the growth of stoichiometric CdS without the formation of any intermediate phases at the CdS-polyvinyl alcohol interface. Raman spectra of first order longitudinal optical phonon peak has been analyzed using phonon dispersion model to detect the surface phonon modes in CdS nanoneedles and wires. The origin of negative differential resistance behavior in current-voltage characteristics for junctionlike CdS nanocomposites has been discussed.
Nanometer scale light focusing with high cavity-enhanced output
Authors: Consonni M. , Hazart J. , Lérondel G. , Vial A.
Published: April 2009

Efficient nanoscale optical focusing is demonstrated in double-structured thin metallic films supporting both surface plasmons and cavity eigenmodes. Numerical simulations show that efficient mode coupling can dramatically enhance the transmission of a subwavelength slit. For a spot size of ∼λ/10, the cavity induced enhancement is about an order of magnitude, leading to a final structure output (transmitted power/incident power) of ∼30%. Results are discussed in terms of cavity-slit mode matching and photon trapping within the cavity.
Electron microscopy study of CeOx–Pd/α-Al2O3 catalysts for methane dry reforming
Authors: Moreno M. S. , Wang F. , Malac M. , Kasama T. , Gigola C. E. , Costilla I. , Sánchez M. D.
Published: April 2009

We have investigated the interaction between Pd and Ce in a (0.47 wt %) CeOx–Pd(1 wt %)/α-Al2O3 catalyst that is used in the reforming reaction of CH4 with CO2. The freshly reduced catalyst was characterized by various electron microscopy techniques, such as elemental mapping, Z-contrast imaging, and electron energy-loss spectroscopy to understand the role of Ce on a microscopic scale. The high spatial resolution elemental mapping indicates that CeOx is located in close proximity of the palladium nanoparticles. High-resolution lattice images and energy-loss spectra obtained in the vicinity of the Pd particles show an anisotropic distribution of CeOx crystallites limited to the interface region between Pd and the substrate but not covering the surface of the Pd nanoparticles. Energy-loss near edge fine structure of Pd M edges reveals that the Pd nanoparticles are not oxidized.
Structural, electrical, and magnetic properties of chemical solution deposited Bi(Fe0.95Cr0.05)O3 thin films on platinized silicon substrates
Authors: Murari N. M. , Thomas R. , Winterman A. , Melgarejo R. E. , Pavunny S. P. , Katiyar R. S.
Published: April 2009

Polycrystalline BiFeO3 and Bi(Fe0.95Cr0.05)O3 thin films were deposited on Pt/TiO2/SiO2/Si substrates by chemical solution deposition. Their structural, electrical, and magnetic properties were measured and compared. The prominent splitting around 2θ∼32° for the 104/110 reflections and the resemblance of Raman spectra with BiFeO3 suggests structural invariance upon Cr substitution (≤5%). The surface morphology of the films showed uniform granular grains; roughness and the grain sizes reduced considerably with Cr substitution. In the case of Bi(Fe0.95Cr0.05)O3 thin films, all Raman active modes disappeared at 700 °C suggesting a structural phase transition with the reduced transition temperature compared to pure BFO. The dielectric constant of pure BiFeO3 film is approximately 50 at 1 MHz and it increased to 66 with 5% Cr substitution. The leakage current reduced in Bi(Fe0.95Cr0.05)O3 thin films and the current conduction was due to Poole–Frenkel mechanism compared to the space charge limited current conduction in BiFeO3. The saturated magnetization was observed in both cases with higher saturation magnetization in the case of Bi(Fe0.95Cr0.05)O3 thin films. Higher net polarization and saturated P-V hysteresis were obtained for Bi(Fe0.95Cr0.05)O3 compared with BiFeO3 films.
A new cavity based absorption instrument for detection of water isotopologues in the upper troposphere and lower stratosphere
Authors: Sayres David S. , Moyer E. J. , Hanisco T. F. , St. Clair J. M. , Keutsch F. N. , O’Brien A. , Allen N. T. , Lapson L. , Demusz J. N. , Rivero M. , Martin T. , Greenberg M. , Tuozzolo C. , Engel G. S. , Kroll J. H. , Paul J. B. , Anderson J. G.
Published: April 2009

We describe here the Harvard integrated cavity output spectroscopy (ICOS) isotope instrument, a mid-IR infrared spectrometer using ICOS to make in situ measurements of the primary isotopologues of water vapor (H2O, HDO, and H218O) in the upper troposphere and lower stratosphere (UTLS). The long path length provided by ICOS provides the sensitivity and accuracy necessary to measure these or other trace atmospheric species at concentrations in the ppbv range. The Harvard ICOS isotope instrument has been integrated onto NASA’s WB-57 high-altitude research aircraft and to date has flown successfully in four field campaigns from winter 2004–2005 to the present. Off-axis alignment and a fully passive cavity ensure maximum robustness against the vibrationally hostile aircraft environment. The very simple instrument design permitted by off-axis ICOS is also helpful in minimizing contamination necessary for accurate measurements in the dry UTLS region. The instrument is calibrated in the laboratory via two separate water addition systems and crosscalibrated against other instruments. Calibrations have established an accuracy of 5% for all species. The instrument has demonstrated measurement precision of 0.14 ppmv, 0.10 ppbv, and 0.16 ppbv in 4 s averages for H2O, HDO, and H218O, respectively. At a water vapor mixing ratio of 5 ppmv the isotopologue ratio precision is 50‰ and 30‰ for δD and δ18O, respectively.
Magnetic force driven six degree-of-freedom active vibration isolation system using a phase compensated velocity sensor
Authors: Kim Yongdae , Kim Sangyoo , Park Kyihwan
Published: April 2009

A six-axis active vibration isolation system (AVIS) is developed using voice coil actuators. Point contact configuration is employed to have an easy assembly of eight voice coil actuators to an upper and a base plates. The velocity sensor, using an electromagnetic principle that is commonly used in the vibration control, is investigated since its phase lead characteristic causes an instability problem for a low frequency vibration. The performances of the AVIS are investigated in the frequency domain and finally validated by comparing with the passive isolation system using the atomic force microscope images.
Analysis of wave propagation and localization in periodic/disordered layered composite structures by a mass-spring model
Authors: Yan Zhi-Zhong , Zhang Chuanzeng , Wang Yue-Sheng
Published: April 2009

The band structure and the displacement field of elastic waves in periodic/disordered layered composite structures of finite width are investigated by a simple mass-spring model. In the case of comparable stiffness, the density contrast plays a dominant role for the center layer disorder to obtain localized wave modes within the band gap. On the other hand, in the case of comparable density contrast, the number and the position of the localized modes can be adjusted by changing the stiffness of the center layer. Compared to the soft and nearly cracked disorders situated between two layers with a lower density, the band structure and the displacement are quite different from the case between two layers with a higher density.
On some fractional Green’s functions
Authors: Camargo R. Figueiredo , Charnet R. , Capelas de Oliveira E.
Published: April 2009

In this paper we discuss some fractional Green’s functions associated with the fractional differential equations which appear in several fields of science, more precisely, the so-called wave reaction-diffusion equation and some of its particular cases. The methodology presented is the juxtaposition of integral transforms, in particular, the Laplace and the Fourier integral transforms. Some recent results involving the reaction-diffusion equation are pointed out.
Dissociation aided and side chain sampling enhanced Hamiltonian replica exchange
Authors: Mu Yuguang
Published: April 2009

A new application of Hamiltonian replica exchange method is suggested: The potential energy function is adjusted in such a way that repulsive forces between atoms of solute are reinforced. This dissociation action helps the system to escape from the local minima on the free energy landscape. Compared with other Hamiltonian replica exchange methods in which the potential energy between solute atoms and between solute and solvent atoms was reduced, and compared with the temperature replica exchange method, the new scheme displays superior ability to overcome large free energy barrier in a model system. For protein simulation, the side chain conformation sampling turns out to be an issue and an enhancement method is introduced. Combining the dissociation aided method with the specific side chain sampling technique is proven to be a help to explore the complex energy landscape of protein, which is demonstrated by three independent ab initio folding simulations on the trpzip2 peptide.
Transport properties of highly asymmetric hard-sphere mixtures
Authors: Bannerman Marcus N. , Lue Leo
Published: April 2009

The static and dynamic properties of binary mixtures of hard spheres with a diameter ratio of σB/σA=0.1 and a mass ratio of mB/mA=0.001 are investigated using event driven molecular dynamics. The contact values of the pair correlation functions are found to compare favorably with recently proposed theoretical expressions. The transport coefficients of the mixture, determined from simulation, are compared to the predictions of the revised Enskog theory using both a third-order Sonine expansion and direct simulation Monte Carlo. Overall, the Enskog theory provides a fairly good description of the simulation data, with the exception of systems at the smallest mole fraction of larger spheres (xA=0.01) examined. A “fines effect” was observed at higher packing fractions, where adding smaller spheres to a system of large spheres decreases the viscosity of the mixture; this effect is not captured by the Enskog theory.
A setup combining magneto-optical Kerr effect and conversion electron Mössbauer spectrometry for analysis of the near-surface magnetic properties of thin films
Authors: Juraszek J. , Zivotsky O. , Chiron H. , Vaudolon C. , Teillet J.
Published: April 2009

We propose a system allowing the characterization of thin magnetic multilayer structures that combine conversion electron Mössbauer spectrometry (CEMS) under applied magnetic field with the magneto-optical Kerr effect (MOKE) technique. Measured hysteresis loops obtained from the MOKE part are used for investigation of sample surface magnetic properties. The CEMS part of such a system is suitable for studying the spatial spin distribution during magnetization reversal under applied magnetic field, whose values are established from the measured MOKE loop. The combined technique is demonstrated on the results obtained at 300 K on an exchange-coupled ferrimagnetic amorphous GdFe/TbFe bilayer, where the center of the GdFe layer is enriched in F57e. Both techniques confirm in-plane uniaxial anisotropy. The spin structure at the position of the probe layer is analyzed for several values of the external magnetic field applied in the hard magnetization axis direction.
Rotation of methyl radicals in a solid krypton matrix
Authors: Kiljunen Toni , Popov Evgeny , Kunttu Henrik , Eloranta Jussi
Published: April 2009

Electron spin resonance (ESR) measurements were carried out to study the rotation of methyl radicals (CH3) in a solid krypton matrix at 17–31K temperature range. The radicals were produced by dissociating methane by plasma bursts generated by a focused 193nm excimer laser radiation during the krypton gas condensation on the substrate. The ESR spectrum exhibits only isotropic features at the temperature range examined, and the intensity ratio between the symmetric (A) and antisymmetric (E) spin state lines exhibits weaker temperature dependence than in a solid argon matrix. However, the general appearance of the methyl radical spectrum depends strongly on temperature due to the pronounced temperature dependency of the E state linewidths. The rotational energy level populations are analyzed based on the static crystal field model, pseudorotating cage model, and quantum chemical calculations for an axially symmetric, planar rotor. Crystal field strength parameter values of −140cm−1 in Ar and −240cm−1 in Kr match most closely the experimentally observed rotational energy level shifts from the gas phase value. In the alternative model, considering the lattice atom movement in a pseudorotating cage, the effective lowering of the rotational constants B and C to 80%–90% leads to similar effects.
Electrical field induced precipitation reaction and percolation in Ag30Ge17Se53 amorphous electrolyte films
Authors: Chen Liang , Liu Zhiguo , Xia Yidong , Yin Kuibo , Gao Ligang , Yin Jiang
Published: April 2009

The microstructural evolution and resistive switching of glassy Ag30Ge17Se53 electrolyte films clipped by Ag active electrode, at which a positive bias was applied, and Pt inert electrode, were investigated by transmission electron microscopy observations and I-V measurements as functions of the period of electrical field treatment. It is revealed that an electrical field induced precipitation reaction forming conductive particles with orthorhombic Ag2Se structure and followed growth and networking of these particles, leading to an electrical percolation, are responsible for the transition from high resistive to high conductive state of the system. The kinetics of the precipitation reaction was also analyzed.
A low-temperature method for improving the performance of sputter-deposited ZnO thin-film transistors with supercritical fluid
Authors: Chen Min-Chen , Chang Ting-Chang , Huang Sheng-Yao , Chang Kuan-Chang , Li Hung-Wei , Chen Shih-Ching , Lu Jin , Shi Yi
Published: April 2009

A low-temperature method, supercritical CO2 (SCCO2) fluid technology, is employed to improve the device properties of ZnO TFT at 150 °C. In this work, the undoped ZnO films were deposited by sputter at room temperature and treated by SCCO2 fluid which is mixed with 5 ml pure H2O. After SCCO2 treatment, the on/off current ratios and threshold voltage of the device were improved significantly. From x-ray photoelectron spectroscopy analyses, the enhancements were attributed to the stronger Zn–O bonds, the hydrogen-related donors, and the reduction in dangling bonds at the grain boundary by OH passivation.
On generation of picosecond inhomogeneous shear strain fronts by laser-induced gratings
Authors: Gusev Vitalyi
Published: April 2009

The processes leading to excitation of inhomogeneous, plane compression/dilatation bulk acoustic strain pulses and shear bulk acoustic strain fronts following the creation of a transient laser interference pattern at a mechanically free surface of an elastically isotropic medium are described. It is shown that the characteristic frequencies of these acoustic disturbances can be much higher than those corresponding to the spatial period of the laser-induced grating. As well, it is shown that the inherent dispersive nature of these bulk acoustic eigenmodes provides plausible explanation for the reported observations of acoustic echo transformation in thin film, ultrafast laser ultrasonics experiments.
Age Effects on the Perception of Motion Illusions
Authors: Billino Jutta , Hamburger Kai , Gegenfurtner Karl R
Published: April 2009

Anomalous motion illusions represent a popular class of illusions and several studies have made an effort to explain their perception. However, understanding is still inconsistent. Age-related differences in susceptibility to illusory motion may contribute to further clarification of the underlying processing mechanisms. We investigated the effect of age on the perception of four different anomalous motion illusions. The Enigma illusion, the Rotating-Snakes illusion, the Pinna illusion, and the Rotating-Tilted-Lines illusion were tested on a total of one hundred and thirty-nine participants covering an age range from 3 to 82 years. In comparison with young adults, children showed a lower likelihood of perceiving motion in all illusions with the exception of the Rotating-Tilted-Lines illusion. For adult subjects, we found significant age effects in the Rotating-Snakes illusion and the Rotating-Tilted-Lines illusion: occurrence of the illusory effect decreased with age. The other two illusions turned out to be unaffected by aging. Finally, inter-correlations between different motion illusions revealed that only the Pinna illusion and the Rotating-Tilted-Lines illusion correlated significantly with each other. The results confirm that anomalous motion illusions should not be considered as a homogeneous group. Possible links between perceptual data and neurophysiological changes related to age are discussed. Perceptual differences due to age provide the opportunity to improve our understanding of illusory motion and point to specific underlying mechanisms.
Do Pictures of Faces, and Which Ones, Capture Attention in the Inattentional-Blindness Paradigm?
Authors: Devue Christel , Laloyaux Cédric , Feyers Dorothée , Theeuwes Jan , Brédart Serge
Published: April 2009

Faces and self-referential material (eg one's own name) are more likely to capture attention in the inattentional-blindness (IB) paradigm than other stimuli. This effect is presumably due to the meaning of these stimuli rather than to their familiarity [Mack and Rock, 1998 Inattentional Blindness (Cambridge, MA: MIT Press)]. In previous work, IB has been investigated mostly with schematic stimuli. In the present study, the generalisability of this finding was tested with photographic stimuli. In support of the view that faces constitute a special category of stimuli, pictures of faces were found to resist more to IB than pictures of common objects (experiment 1) or than pictures of inverted faces (experiment 2). In a third experiment, the influence of face familiarity and identity (the participant's own face, a friend's face, and an unknown face) on IB rates was evaluated. Unexpectedly, no differential resistence to blindness across these three kinds of faces was found. In conclusion, pictures of faces attracted attention more than pictures of objects or inverted faces in the IB paradigm. However, this effect was not dependent on face familiarity or identity.
Identification and structural basis of the reaction catalyzed by CYP121, an essential cytochrome P450 in
Mycobacterium tuberculosis
Authors: Belin Pascal , Le Du Marie Hélène , Fielding Alistair , Lequin Olivier , Jacquet Mickaël , Charbonnier Jean-Baptiste , Lecoq Alain , Thai Robert , Courçon Marie , Masson Cédric , Dugave Christophe , Genet Roger , Pernodet Jean-Luc , Gondry Muriel
Published: April 2009

The gene encoding the cytochrome P450 CYP121 is essential for
Mycobacterium tuberculosis
. However, the CYP121 catalytic activity remains unknown. Here, we show that the cyclodipeptide cyclo(l-Tyr-l-Tyr) (cYY) binds to CYP121, and is efficiently converted into a single major product in a CYP121 activity assay containing spinach ferredoxin and ferredoxin reductase. NMR spectroscopy analysis of the reaction product shows that CYP121 catalyzes the formation of an intramolecular C-C bond between 2 tyrosyl carbon atoms of cYY resulting in a novel chemical entity. The X-ray structure of cYY-bound CYP121, solved at high resolution (1.4 Å), reveals one cYY molecule with full occupancy in the large active site cavity. One cYY tyrosyl approaches the heme and establishes a specific H-bonding network with Ser-237, Gln-385, Arg-386, and 3 water molecules, including the sixth iron ligand. These observations are consistent with low temperature EPR spectra of cYY-bound CYP121 showing a change in the heme environment with the persistence of the sixth heme iron ligand. As the carbon atoms involved in the final C-C coupling are located 5.4 Å apart according to the CYP121-cYY complex crystal structure, we propose that C-C coupling is concomitant with substrate tyrosyl movements. This study provides insight into the catalytic activity, mechanism, and biological function of CYP121. Also, it provides clues for rational design of putative CYP121 substrate-based antimycobacterial agents.
Docking for fragment inhibitors of AmpC β-lactamase
Authors: Teotico Denise G. , Babaoglu Kerim , Rocklin Gabriel J. , Ferreira Rafaela S. , Giannetti Anthony M. , Shoichet Brian K.
Published: April 2009

Fragment screens for new ligands have had wide success, notwithstanding their constraint to libraries of 1,000–10,000 molecules. Larger libraries would be addressable were molecular docking reliable for fragment screens, but this has not been widely accepted. To investigate docking's ability to prioritize fragments, a library of >137,000 such molecules were docked against the structure of β-lactamase. Forty-eight fragments highly ranked by docking were acquired and tested; 23 had

K
i

values ranging from 0.7 to 9.2 mM. X-ray crystal structures of the enzyme-bound complexes were determined for 8 of the fragments. For 4, the correspondence between the predicted and experimental structures was high (RMSD between 1.2 and 1.4 Å), whereas for another 2, the fidelity was lower but retained most key interactions (RMSD 2.4–2.6 Å). Two of the 8 fragments adopted very different poses in the active site owing to enzyme conformational changes. The 48% hit rate of the fragment docking compares very favorably with “lead-like” docking and high-throughput screening against the same enzyme. To understand this, we investigated the occurrence of the fragment scaffolds among larger, lead-like molecules. Approximately 1% of commercially available fragments contain these inhibitors whereas only 10
−7
% of lead-like molecules do. This suggests that many more chemotypes and combinations of chemotypes are present among fragments than are available among lead-like molecules, contributing to the higher hit rates. The ability of docking to prioritize these fragments suggests that the technique can be used to exploit the better chemotype coverage that exists at the fragment level.
It's not what you play, it's how you play it: Timbre affects perception of emotion in music
Authors: Hailstone Julia C. , Omar Rohani , Henley Susie M. D. , Frost Chris , Kenward Michael G. , Warren Jason D.
Published: April 2009

Salient sensory experiences often have a strong emotional tone, but the neuropsychological relations between perceptual characteristics of sensory objects and the affective information they convey remain poorly defined. Here we addressed the relationship between sound identity and emotional information using music. In two experiments, we investigated whether perception of emotions is influenced by altering the musical instrument on which the music is played, independently of other musical features. In the first experiment, 40 novel melodies each representing one of four emotions (happiness, sadness, fear, or anger) were each recorded on four different instruments (an electronic synthesizer, a piano, a violin, and a trumpet), controlling for melody, tempo, and loudness between instruments. Healthy participants (23 young adults aged 18–30 years, 24 older adults aged 58–75 years) were asked to select which emotion they thought each musical stimulus represented in a four-alternative forced-choice task. Using a generalized linear mixed model we found a significant interaction between instrument and emotion judgement with a similar pattern in young and older adults ( p < .0001 for each age group). The effect was not attributable to musical expertise. In the second experiment using the same melodies and experimental design, the interaction between timbre and perceived emotion was replicated ( p < .05) in another group of young adults for novel synthetic timbres designed to incorporate timbral cues to particular emotions. Our findings show that timbre (instrument identity) independently affects the perception of emotions in music after controlling for other acoustic, cognitive, and performance factors.
Weighting of contingency information in causal judgement: Evidence of hypothesis dependence and use of a positive-test strategy
Authors: Mandel David R. , Vartanian Oshin
Published: April 2009

Contingency is an important cue to causation. Research shows that people unequally weight the cells of a 2 × 2 contingency table as follows: cause-present/effect-present (A) > cause-present/effect-absent (B) > cause-absent/effect-present (C) > cause-absent/effect-absent (D). Although some models of causal judgement can accommodate that fact, most of them assume that the weighting of information is invariant as a function of whether one is assessing a hypothesized generative versus preventive relationship. An experiment was conducted that tested the hypothesis-independence assumption against the predictions of a novel weighted-positive-test-strategy account, which predicts hypothesis dependence in cell weighting. Supporting that account, judgements of hypothesized generative causes showed the standard A > B > C > D inequality, but judgements of hypothesized preventive causes showed the predicted B > A > D > C inequality. The findings reveal that cell weighting in causal judgement is both unequal and hypothesis dependent.
Are memories for duration modality specific?
Authors: Ogden Ruth S. , Wearden John H. , Jones Luke A.
Published: April 2009

Four experiments examined the effects of encoding multiple standards in a temporal generalization task in the visual and auditory modalities both singly and cross-modally, using stimulus durations ranging, across different experiments, from 100 to 1,400 ms. Previous work has shown that encoding and storing multiple auditory standards of different durations resulted in systematic interference with the memory of the standard, characterized by a shift in the location of peak responding, and this result, from Ogden, Wearden, and Jones (2008), was replicated in the present Experiment 1. Experiment 2 employed the basic procedure of Ogden et al. using visual stimuli and found that encoding multiple visual standards did not lead to performance deterioration or any evidence of systematic interference between the standards. Experiments 3 and 4 examined potential cross-modal interference. When two standards of different modalities and durations were encoded and stored together there was also no evidence of interference between the two. Taken together, these results, and those of Ogden et al., suggest that, in humans, visual temporal reference memory may be more permanent than auditory reference memory and that auditory temporal information and visual temporal information do not mutually interfere in reference memory.
Rab7 Activation by Growth Factor Withdrawal Contributes to the Induction of Apoptosis
Authors: Romero Rosales Kimberly , Peralta Eigen R. , Guenther Garret G. , Wong Susan Y. , Edinger Aimee L.
Published: April 2009

The Rab7 GTPase promotes membrane fusion reactions between late endosomes and lysosomes. In previous studies, we demonstrated that Rab7 inactivation blocks growth factor withdrawal-induced cell death. These results led us to hypothesize that growth factor withdrawal activates Rab7. Here, we show that growth factor deprivation increased both the fraction of Rab7 that was associated with cellular membranes and the percentage of Rab7 bound to guanosine triphosphate (GTP). Moreover, expressing a constitutively GTP-bound mutant of Rab7, Rab7-Q67L, was sufficient to trigger cell death even in the presence of growth factors. This activated Rab7 mutant was also able to reverse the growth factor-independent cell survival conferred by protein kinase C (PKC) δ inhibition. PKCδ is one of the most highly induced proteins after growth factor withdrawal and contributes to the induction of apoptosis. To evaluate whether PKCδ regulates Rab7, we first examined lysosomal morphology in cells with reduced PKCδ activity. Consistent with a potential role as a Rab7 activator, blocking PKCδ function caused profound lysosomal fragmentation comparable to that observed when Rab7 was directly inhibited. Interestingly, PKCδ inhibition fragmented the lysosome without decreasing Rab7-GTP levels. Taken together, these results suggest that Rab7 activation by growth factor withdrawal contributes to the induction of apoptosis and that Rab7-dependent fusion reactions may be targeted by signaling pathways that limit growth factor-independent cell survival.
Evaluation of the quality of the North Sea herring assessment
Authors: Simmonds E. John
Published: April 2009

Simmonds, E. J. 2009. Evaluation of the quality of the North Sea herring assessment. – ICES Journal of Marine Science, 66: 1814–1822. The assessment of North Sea herring has been used to give advice on catch quota for more than 20 years. The data sources comprise acoustic surveys, International Bottom Trawl Surveys, Methot Isaacs–Kidd net post-larval surveys, larval surveys, and catch-at-age data. These sources and their uses are briefly reviewed, and the changes in the weighting attached to each index in the assessment over time are discussed. The performance of the assessment is examined both in historical and analytical retrospectives of spawning–stock biomass and fishing mortality, and in retrospective assessments of numbers by cohort. Increased length of the time-series, the use of a statistical model with appropriate weighting, and a more consistent management strategy have all contributed to the assessment becoming highly stable from one year to the next. The results presented lead to the conclusion that the assessments provide an excellent basis for the management of this stock.
How to collect verifiable length data on tuna from photographs: an approach for sample vessels
Authors: Chang Shui-Kai , Lin Ta-Te , Lin Ghung-Hui , Chang Hsiang-Yun , Hsieh Ching-Lu
Published: April 2009

Chang, S-K., Lin, T-T., Lin, G-H., Chang, H-Y., and Hsieh, C-L. 2009. How to collect verifiable length data on tuna from photographs: an approach for sample vessels. – ICES Journal of Marine Science, 66: 907–915. Length frequencies are essential data for fish stock assessments, particularly for longer-lived species. They are usually provided by commercial vessels, or by port sampling, observers, or sample-vessel programmes, but each of these has limitations. Collection by sample vessels might be the most balanced way if the data quality is verifiable. We introduce a photograph-based length-measurement approach for sample vessels to photograph fish images with a calibration board, using a regular digital camera to obtain length estimates that can be verified after the images are transformed to reduce errors of perspective distortions. We analyse this approach under ideal conditions, develop a set of objective criteria for choosing acceptable photographs from observers, and compare estimated lengths for bigeye tuna (Thunnus obesus) based on this approach with lengths measured by observers. The criteria can serve as guidelines for photographing: if images are captured following these guidelines, the approach shows the potential for obtaining cheaply a large quantity of length estimates that deviate around 3% (up and down) on average from the actual measurements taken by observers.
On the problems of a closed marriage: celebrating Darwin 200
Authors: Pannell John R.
Published: April 2009

Darwin devoted much of his working life to the study of plant reproductive systems. He recognized that many of the intricacies of floral morphology had been shaped by natural selection in favour of outcrossing, and he clearly established the deleterious effects of self-fertilization on progeny. Although Darwin hypothesized the adaptive significance of self-fertilization under conditions of low mate availability, he held that a strategy of pure selfing would be strongly disadvantageous in the long term. Here, I briefly review these contributions to our understanding of plant reproduction. I then suggest that investigating two very different sexual systems, one in plants and the other in animals, would throw further light on the long-term implications of a commitment to reproduction exclusively by selfing.