bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of free school lunch in the associations between family-environmental factors and children's fruit and vegetable intake in four European countries
Authors: Ray Carola , Roos Eva , Brug Johannes , Behrendt Isabel , Ehrenblad Bettina , Yngve Agneta , te Velde Saskia J
Published: September 2012

Objective

To determine whether an association exists between different clusters of fruit- and vegetable-specific family-environmental factors and children's daily fruit and vegetable intake, and whether these associations differ between countries with different school lunch policies.

Design

Cross-sectional data from four European countries participating in the Pro Greens project in 2009. These countries have different school food policies: two serve free school lunches and two do not. Self-administered data were used. Food frequency questions served to assess fruit and vegetable intakes. The study assessed sixteen children-perceived family-environmental factors, which were clustered based on principal component analysis into five sum variables: fruit and vegetable encouragement; vegetable modelling, family routine and demand; fruit modelling; fruit and vegetable snacking practices; and fruit and vegetable allowing.

Setting

Schools in Finland, Germany, Sweden and the Netherlands.

Subjects

Schoolchildren aged 11 years (n3317).

Results

Multilevel logistic regression analyses revealed positive associations between nearly all clustered family-environmental factors and daily fruit and vegetable intake. The study tested a moderation effect between family-environmental factors and school lunch policy. In five out of twenty models significant interactions occurred. In the stratified analyses, most of the associations between family-environmental factors and raw and cooked vegetable intake were stronger in Germany and the Netherlands, neither of which provided free school lunches.

Conclusions

Children reporting more fruit- and vegetable-promoting family-environmental factors had a more frequent intake of fruits and vegetables; the associations were stronger for vegetable intakes in countries providing no free school lunches, suggesting that parental involvement is crucial when schools offer no vegetables.
The Court of Strasbourg Acting as an Asylum Court
Authors: Bossuyt Marc
Published: September 2012

Article 3 ECHR and expulsion, extradition – Indirect and potential violations – Interim measures – Lowering of threshold – Transformation from civil to social right – Asylum seekers special vulnerable group
Arbeitsgedächtnisprofile von Kindern unterschiedlicher Begabungsniveaus
Authors: Schuchardt Kirsten , Mähler Claudia
Published: September 2012

Zusammenfassung: Das Interesse der vorliegenden Arbeit besteht in der Klärung des Verhältnisses zwischen Arbeitsgedächtnis und Intelligenz. Es soll die Frage untersucht werden, ob Intelligenzunterschiede mit spezifischen Arbeitsgedächtnisprofilen, d. h. mit spezifischen Stärken und Schwächen im Arbeitsgedächtnis einhergehen. Hierbei wurde das Arbeitsgedächtnismodell von Baddeley zugrunde gelegt, um differenzierte Analysen der Subsysteme Zentrale Exekutive, Phonologische Schleife und Visuell-räumlicher Notizblock vorzunehmen.

An der Studie nahmen 18 Kinder mit weit überdurchschnittlicher Intelligenz (IQ von 121 bis 148), 21 Kinder mit deutlich unterdurchschnittlicher Intelligenz (IQ von 54 bis 79) und eine durchschnittliche Kontrollgruppe von 23 Kindern (IQ von 90 bis 110) teil. Alle Kinder bearbeiteten im Einzelversuch eine umfangreiche Testbatterie mit Aufgaben zu allen Subkomponenten des Arbeitsgedächtnisses. Die Ergebnisse belegen Gruppenunterschiede in allen Bereichen des Arbeitsgedächtnisses, aber auch subsystemspezifische Stärken bzw. Schwächen in Abhängigkeit vom Intelligenzniveau. Diese charakteristischen Leistungsmuster in den Arbeitsgedächtnisfunktionen werden als Grundlage für das jeweils unterschiedliche Lernpotenzial und Schulerfolg diskutiert.
Kritik am Diskrepanzkriterium in der Diagnostik von Legasthenie und Dyskalkulie
Authors: Ehlert Antje , Schroeders Ulrich , Fritz-Stratmann Annemarie
Published: September 2012

Zusammenfassung: Laut den beiden großen internationalen Klassifikationssystemen psychischer Störungen, ICD-10 und DSM-IV-TR, muss zur Diagnose einer Dyskalkulie oder Legasthenie u. a. eine Diskrepanz zwischen der auf Grund allgemeiner kognitiver Leistung zu erwartenden und der tatsächlichen Rechenleistung vorliegen. Im ersten Teil dieses Beitrags soll die national und international geäußerte Kritik zu inhaltlichen und methodischen Schwächen aufgegriffen und gebündelt diskutiert werden. Die Annahme einer Diskrepanz impliziert auch, dass sich rechenschwache Kinder, deren Rechenleistung zusätzlich das Diskrepanzkriterium erfüllt, von anderen rechenschwachen Kindern abgrenzen lassen. Um diese Vorstellung zu entkräften, soll in einem zweiten Schritt empirisch überprüft werden, inwiefern eine auf der Diskrepanz zwischen erwarteter und gemessener Rechenleistung basierende Gruppenzuordnung künstlich oder gerechtfertigt ist. Dazu wurden die rechenschwachen Kinder einer geschichteten Stichprobe bestehend aus 458 Kindern zwei Gruppen zugewiesen: Die Kinder der ersten Gruppe zeigen schwache Rechenleistungen in einem curricular orientierten Rechentest und schneiden auch schlechter ab als auf Grund eines Intelligenztests zu erwarten wäre. Die rechenschwachen Kinder der zweiten Gruppe erfüllen das Diskrepanzkriterium hingegen nicht. Die beiden Gruppen werden hinsichtlich ihres Verständnisses mathematischer Konzepte mit Hilfe eines kriterienorientierten Tests, der auf dem mathematischen Kompetenzstufenmodell von Fritz und Ricken (2008*) beruht ( Fritz, Ricken, Balzer, Leutner & Willmes, 2012 ), miteinander verglichen. Es zeigt sich, dass die Kinder der beiden rechenschwachen Gruppen über dieselben mathematischen Konzepte verfügen. Deswegen legen sowohl die wissenschaftlich-theoretische Diskussion als auch die Ergebnisse der empirischen Studie den Schluss nahe, dass die Verwendung eines Diskrepanzkriteriums in der Diagnostik einer Teilleistungsschwäche fraglich ist und durch eine kriterienorientierte Diagnostik, die auf basale numerische Grundfähigkeiten fokussiert, ersetzt werden sollte.
Navigations of chemical space to further the understanding of polypharmacology in human nuclear receptors
Authors: Macchiarulo Antonio , Carotti Andrea , Cellanetti Marco , Sardella Roccaldo , Gioiello Antimo
Published: September 2012

The article analyses properties featuring the binding site of human nuclear receptors and cognate ligands, investigating aspects of polypharmacology.
Prognostic value of uric acid in patients with Type 2 diabetes mellitus and coronary artery disease
Authors: Ndrepepa Gjin , Braun Siegmund , King Lamin , Cassese Salvatore , Tada Tomohisa , Fusaro Massimiliano , Hadamitzky Martin , Haase Hans-Ullrich , Schömig Albert , Kastrati Adnan
Published: September 2012

Studies investigating the prognostic role of UA (uric acid) in patients with Type 2 diabetes mellitus have given conflicting findings. We undertook the present study to assess the association between UA and outcome in patients with Type 2 diabetes mellitus and CAD (coronary artery disease). The study included 3705 patients with diabetes mellitus and angiography-proven CAD. UA was measured before coronary angiography. The primary outcome was 1-year all-cause mortality. The UA concentration [median (25th–75th quartiles)] was 6.44 mg/dl (5.40–7.70 mg/dl). There were 264 deaths (7.1%) during follow-up: 45 deaths in patients of the first UA quartile, 43 deaths in patients of the second UA quartile, 51 deaths in patients of the third UA quartile and 125 deaths in patients of the fourth UA quartile {Kaplan–Meier estimates of mortality, 5.1, 4.8, 5.6 and 14.0% respectively; unadjusted HR (hazard ratio), 2.81 [95% CI (confidence interval), 2.21–3.58]; P<0.001 for fourth quartile compared with first–third quartiles combined}. In the multivariable analysis, UA predicted all-cause mortality with an adjusted HR of 1.29 (95% CI, 1.12–1.48; P<0.001), for each S.D. increase in the logarithmic scale of UA level. The inclusion of UA in the multivariable model alongside known cardiovascular risk factors and other relevant variables increased the discriminatory power of the model regarding prediction of all-cause mortality [absolute and relative IDI (integrated discrimination improvement) 0.034 and 20.5% respectively; P<0.001]. In conclusion, in patients with Type 2 diabetes mellitus and confirmed CAD, elevated levels of UA predict mortality independently of known cardiovascular risk factors.
Assessment of the accuracy the experimental energies of the 1P
o 1s22s6p and 1s22s7p states of 9Be based on variational calculations with explicitly correlated Gaussians
Authors: Bubin Sergiy , Adamowicz Ludwik
Published: September 2012

Benchmark variational calculations are performed for the six lowest states of the 1Po 1s22snp state series of the 9Be atom. The wave functions of the states are expanded in terms of all-particle, explicitly correlated Gaussian basis functions and the effect of the finite nuclear mass is directly included in the calculations. The exponential parameters of the Gaussians are variationally optimized using the analytical energy gradient determined with respect to those parameters. Besides providing reference non-relativistic energies for the considered states, the calculations also allow to assess the accuracy of the experimental energies of the 1Po 1s22s6p and 1s22s7p states and suggest their refinement.
Temperature dependence of Mg-H local vibrational modes in heavily doped InN:Mg
Authors: Cuscó Ramon , Domènech-Amador Núria , Artús Luis , Wang Ke , Yamaguchi Tomohiro , Nanishi Yasushi
Published: September 2012

We have studied the temperature dependence and anharmonic coupling of the local vibrational modes (LVMs) associated with Mg-H complexes in heavily doped InN:Mg. Two main LVM peaks are observed which are probably related to two different H-impurity bond lengths. The temperature dependence of the higher-frequency mode, which exhibits a monotonic frequency downshift and broadening with increasing temperature, can be explained by LVM dephasing due to acoustic phonon scattering. The lower-frequency mode displays an anomalous behavior as its frequency decreases initially and then starts to increase linearly above room temperature. The anharmonic coupling of the lower-frequency mode to a molecular mode of the impurity complex is suggested as a possible cause for this behavior.
Molecular dynamics simulation of the effect of bond flexibility on the transport properties of water
Authors: Raabe Gabriele , Sadus Richard J.
Published: September 2012

Molecular dynamics simulations for the shear viscosity and self-diffusion coefficient of pure water were performed to investigate the effect of including intramolecular degrees of freedom in simple point charge (SPC) models over a wide range of state points. Results are reported for the flexible SPC/Fw model, its rigid SPC counterpart, and the widely used SPC/E model. The simulations covered the liquid phase from 277.15 to 363.15 K and the supercritical phase at 673.15 K and pressures up to 200 MPa. The flexibility exhibited by the SPC/Fw model results in slowing down of the dynamics. That is, it results in higher shear viscosities and lower diffusion coefficients than can be obtained from the rigid model, resulting in better agreement with experimental data. Significantly, the SPC/Fw model can be used to adequately predict the diffusion coefficients at ambient and supercritical temperatures over a wide range of pressures.
Linear and nonlinear optical susceptibilities and hyperpolarizability of borate LiNaB4O7 single crystals: Theory and experiment
Authors: Reshak Ali Hussain , Chen Xuean , Auluck S. , Kamarudin H.
Published: September 2012

LiNaB4O7 was synthesized by employing high-temperature reaction methods. The purity of the sample was checked by x-ray powder diffraction. The optical properties were measured by analyzing the diffuse reflectance data which showed a band gap of about 3.88 eV. Linear and nonlinear optical susceptibility calculations have been performed using the all-electron full potential linearized augmented plane wave method using four different exchange correlation potentials. It was found that the title compound possesses an optical gap of about 2.80 eV using the local density approximation, 2.91 eV by generalized gradient approximation, 3.21 eV for the Engel-Vosko generalized gradient approximation (EVGGA), and 3.81 eV using modified Becke-Johnson potential (mBJ). This compares well with our experimentally measured energy band gap of 3.88 eV. Our calculations show that EVGGA and mBJ cause a blue spectral shift with significant changes in the whole spectra. The observed spectral shifts are in agreement with the calculated band structure and corresponding electron density of states. The tensor χijk(2) describes the second-order nonlinear optical effect and the symmetry allows only five nonzero components, namely, the 113, 232, 311, 322, and 333 components with 322 being the dominant one with a value 0.15 pm/V (d32 = 0.0733 pm/V) at static limit and 0.16 pm/V (d32 = 0.0795 pm/V) at λ = 1064 nm. For the dominant component, the microscopic second order hyperpolarizability, β322, was found to be 0.306 × 10−30 esu at static limit and 0.332 × 10−30 esu at λ = 1064 nm.
Size effects in vapor-solid-solid Ge nanowire growth with a Ni-based catalyst
Authors: Thombare S. V. , Marshall A. F. , McIntyre P. C.
Published: September 2012

We report a dramatic size effect on the morphology of Ge nanowires synthesized by low-temperature vapor-solid-solid (VSS) growth using a NiGe catalyst. Nanowires with diameter greater than 25 nm are 〈111〉-oriented, have a high density of grown-in defects, and exhibit frequent kinking. However, nanowires with diameter below 25 nm are straight, despite also having a substantial density of crystal defects. The latter wires grow preferentially in the 〈110〉 direction. The absence of kinking in the small nanowires coincides with the observation of a low-energy, epitaxial NiGe/Ge interface. Our results show that the occurrence of (1) this solid-solid epitaxial interface and (2) the low-energy sidewall facets of the 〈110〉 wire orientation strongly bias the Ni-Ge binary system toward kink-free nanowire growth in the VSS regime. We further demonstrate that kinking in larger nanowires occurs via multiple twinning events facilitated by the slow growth and anisotropic catalyst/wire interfaces typical of VSS growth. Such effects are expected in other VSS systems where a range of nanowire morphologies are observed.
Analysis of the basis set superposition error in molecular dynamics of hydrogen-bonded liquids: Application to methanol
Authors: Van Houteghem Marc , Verstraelen Toon , Ghysels An , Vanduyfhuys Louis , Waroquier Michel , Van Speybroeck Veronique
Published: September 2012

An efficient protocol is presented to compensate for the basis set superposition error (BSSE) in DFT molecular dynamics (MD) simulations using localized Gaussian basis sets. We propose a classical correction term that can be added a posteriori to account for BSSE. It is tested to what extension this term will improve radial distribution functions (RDFs). The proposed term is pairwise between certain atoms in different molecules and was calibrated by fitting reference BSSE data points computed with the counterpoise method. It is verified that the proposed exponential decaying functional form of the model is valid. This work focuses on hydrogen-bonded liquids, i.e., methanol, and more specific on the intermolecular hydrogen bond, but in principle the method is generally applicable on any type of interaction where BSSE is significant. We evaluated the relative importance of the Grimme-dispersion versus BSSE and found that they are of the same order of magnitude, but with an opposite sign. Upon introduction of the correction, the relevant RDFs, obtained from MD, have amplitudes equal to experiment.
Electronic surface compensation of polarization in PbTiO3 films
Authors: He Jun , Stephenson G. B. , Nakhmanson S. M.
Published: September 2012

Using a density-functional-theory-based computational approach we have examined the nature of electronic surface compensation of polarization in PbTiO3 films with bottom electrodes. For film thicknesses up to 12 unit cells, or approximately 5 nm, we find that films are unpolarized, with no significant electronic charge transfer between the film surface and electrode interface. To model the behavior of an infinitely thick film, we froze the ionic positions in two bottom PbTiO3 unit cells to those of the bulk equilibrium polar structure with polarization pointing towards the electrode. In this case, the rest of the film polarizes at about 75% of the bulk value. Electronic compensation on the surface is achieved by the transfer of −0.23 e per unit cell area from the film surface to the electrode-interface region, which makes the 5 outward-most unit cells metallic, with the Pb(6s)-Pb(6p)-O(2p) hybrid state that forms the valence band minimum in the surface PbO monolayer providing most of the compensating charge. Extrapolating the results of the film energy evaluations to thicknesses above 5 nm, we estimate that in films thicker than 14 nm (∼35 unit cells) the electronically compensated monodomain-polarized state is preferred over the nonpolar one.
0.22 THz wideband sheet electron beam traveling wave tube amplifier: Cold test measurements and beam wave interaction analysis
Authors: Baig Anisullah , Gamzina Diana , Barchfeld Robert , Domier Calvin , Barnett Larry R. , Luhmann Neville C.
Published: September 2012

In this paper, we describe micro-fabrication, RF measurements, and particle-in-cell (PIC) simulation modeling analysis of the 0.22 THz double-vane half period staggered traveling wave tube amplifier (TWTA) circuit. The TWTA slow wave structure comprised of two sections separated by two sever ports loaded by loss material, with integrated broadband input/output couplers. The micro-metallic structures were fabricated using nano-CNC milling and diffusion bonded in a three layer process. The 3D optical microscopy and SEM analysis showed that the fabrication error was within 2–3 μm and surface roughness was measured within 30–50 nm. The RF measurements were conducted with an Agilent PNA-X network analyzer employing WR5.1 T/R modules with a frequency range of 178-228 GHz. The in-band insertion loss (S21) for both the short section and long section (separated by a sever) was measured as ∼−5 dB while the return loss was generally around ∼−15 dB or better. The measurements matched well with the S-matrix simulation analysis that predicted a 3 dB bandwidth of ∼45 GHz with an operating frequency at 220 GHz. However, the measured S21 was ∼3 dB less than the design values, and is attributed to surface roughness and alignment issues. The confirmation measurements were conducted over the full frequency band up to 270 GHz employing a backward wave oscillator (BWO) scalar network analyzer setup employing a BWO in the frequency range 190 GHz–270 GHz. PIC simulations were conducted for the realistic TWT output power performance analysis with incorporation of corner radius of 127 μm, which is inevitably induced by nano-machining. Furthermore, the S21 value in both sections of the TWT structure was reduced to correspond to the measurements by using a degraded conductivity of 10% International Annealed Copper Standard. At 220 GHz, for an elliptic sheet electron beam of 20 kV and 0.25 A, the average output power of the tube was predicted to be reduced from 90 W (for ideal conductivity/design S-parameters) to 70 W (for the measured S-parameters/inferred conductivity) for an average input power of 50 mW. The gain of the tube remains reasonable: ∼31.4 dB with an electronic efficiency of ∼1.4%. The same analysis was also conducted for several frequencies between 190 GHz–260 GHz. This detailed realistic PIC analysis demonstrated that this nano-machined TWT circuit has slightly reduced S-parameters and output power from design, but within an acceptable range and still have promising output power, gain, and band width as required. Thus, we expect to meet the specifications of 1000 W-GHz for the darpa program goals.
Structural and optoelectronic properties of P3HT-graphene composites prepared by in situ oxidative polymerization
Authors: Saini Viney , Abdulrazzaq Omar , Bourdo Shawn , Dervishi Enkeleda , Petre Anca , Bairi Venu Gopal , Mustafa Thikra , Schnackenberg Laura , Viswanathan Tito , Biris Alexandru S.
Published: September 2012

Poly(3-hexylthiophene) (P3HT)-graphene nanocomposites were synthesized via in situ oxidative polymerization of 3-hexylthiophene monomer in the presence of graphene. The main thrust was to investigate the structural and optoelectronic properties of P3HT-graphene nanocomposites with various graphene concentrations. NMR spectroscopy was used to determine the regioregularity of the polymer composites, whereas Fourier transform infrared spectroscopy and differential scanning calorimetry were used to study their structural and thermal properties. Moreover, cyclic voltammetry was employed to evaluate the HOMO levels of the nanocomposites, while optical spectrophotometry (UV-Vis-NIR) was utilized to determine the optical bandgap of the composites. The information from the aforementioned techniques was used to estimate the HOMO-LUMO energy levels. The results revealed changes in the optical bandgap of P3HT with increasing graphene content. Furthermore, an extensive study aiming at the effect of graphene content on the optical constants of P3HT was conducted using ellipsometry. Photoluminescence analysis of the samples showed no quenching effect of photoluminescence emission with increasing graphene content. Our studies indicate that the inclusion of graphene impacts the optoelectronic properties of P3HT, which can further be used for advanced applications, such as organic solar cells, organic light emitting diodes, organic field-effect transistors, and polymer batteries.
Nonequilibrium polymer chains induced by conformational transitions in densely interfacial layers
Authors: Zhu Peng-Wei
Published: September 2012

Nonequilibrium poly(N-isopropylacrylamide) (PNIPAM) chains are generated by temperature-induced conformational transitions in the densely interfacial PNIPAM layer at high adsorbed amounts in aqueous solution. The interleaving chains relax in a spatially heterogeneous space of adsorbed layer which is filled with the domains via the hydrogen bonding and hydrophobic interactions. The relaxation dynamics of interleaving chains is changed from the weekly stretched exponential behaviour at the lower adsorbed amount to the strongly stretched exponential behaviour at the higher adsorbed amount. The kinetic constraints for the relaxation dynamics depend on the segment density of the adsorbed layer which is controlled by the temperature. The stretched exponential relaxation is related to an ensemble of relaxations confined in the domains with different physical origins for the heterogeneous dynamics. The range of energy barriers for the relaxation is estimated from the stretched exponent based on the random first order transition theory.
Wertheim's association theory applied to one site patchy colloids: Beyond the single bonding condition
Authors: Marshall Bennett D. , Ballal Deepti , Chapman Walter G.
Published: September 2012

We apply Wertheim's theory to develop an equation of state for one site patchy colloids where the patch can bond multiple times. We allow for the possibility of ring formation without the introduction of empirical parameters and show that for moderate patch coverage the infinite series of chain graphs is well represented by the first two terms. The theory is found to be in excellent agreement with new NVT and NPT Monte Carlo simulations. The approach described here can easily be converted to the form of a density functional theory to describe inhomogeneous patchy colloid systems.
Path integral Monte Carlo with importance sampling for excitons interacting with an arbitrary phonon bath
Authors: Shim Sangwoo , Aspuru-Guzik Alán
Published: September 2012

The reduced density matrix of excitons coupled to a phonon bath at a finite temperature is studied using the path integral Monte Carlo method. Appropriate choices of estimators and importance sampling schemes are crucial to the performance of the Monte Carlo simulation. We show that by choosing the population-normalized estimator for the reduced density matrix, an efficient and physically-meaningful sampling function can be obtained. In addition, the nonadiabatic phonon probability density is obtained as a byproduct during the sampling procedure. For importance sampling, we adopted the Metropolis-adjusted Langevin algorithm. The analytic expression for the gradient of the target probability density function associated with the population-normalized estimator cannot be obtained in closed form without a matrix power series. An approximated gradient that can be efficiently calculated is explored to achieve better computational scaling and efficiency. Application to a simple one-dimensional model system from the previous literature confirms the correctness of the method developed in this manuscript. The displaced harmonic model system within the single exciton manifold shows the numerically exact temperature dependence of the coherence and population of the excitonic system. The sampling scheme can be applied to an arbitrary anharmonic environment, such as multichromophoric systems embedded in the protein complex. The result of this study is expected to stimulate further development of real time propagation methods that satisfy the detailed balance condition for exciton populations.
Investigation of a high power electromagnetic pulse source
Authors: Wang Yuwei , Chen Dongqun , Zhang Jiande , Cao Shengguang , Li Da , Liu Chebo
Published: September 2012

A high power electromagnetic pulse source with a resonant antenna driven by a compact power supply was investigated in this paper. To match the impedance of the resonant antenna and initial power source, a compact power conditioning circuit based on electro exploding opening switch (EEOS) and pulsed transformer was adopted. In the preliminary experiments, an impulse capacitor was used to drive the system. With the opening of the EEOS at the current of 15 kA flowing trough the primary of the transformer, the resonant antenna was rapidly charged to about –370 kV within a time of about 100 ns. When the switch in the resonant antenna closed at the charging voltage of about –202 kV, the peak intensity of the detected electric field at a distance of about 10 m from the center of the source was 7.2 kV/m. The corresponding peak power of the radiated electromagnetic field reached 76 MW, while the total radiated electromagnetic energy was about 0.65 J. The total energy efficiency of the resonant antenna was about 22% which can be improved by increasing the closing rapidity of the switch in the antenna.
Reflection-mode, confocal, tip-enhanced Raman spectroscopy system for scanning chemical microscopy of surfaces
Authors: Ramos R. , Gordon M. J.
Published: September 2012

A reflection-mode, confocal, tip-enhanced Raman spectroscopy system for nanoscale chemical imaging of surfaces is presented. The instrument is based on a beam-bounce atomic force microscope with a side-on Raman microscope with true confocal light illumination and collection. Localized vibrational (Raman) spectroscopy is demonstrated at length scales down to 20 nm on opaque samples. The design and validation of the instrument are discussed with quantitative emphasis on confocal microscope operation, plasmonic properties of the tip, point spectroscopy, and Raman imaging of SiGe nanowires.
Investigation of structural, dielectric, and magnetic properties of hard and soft mixed ferrite composites
Authors: Kotnala R. K. , Ahmad Shahab , Ahmed Arham S. , Shah Jyoti , Azam Ameer
Published: September 2012

Barium ferrite (hard ferrite) and manganese nickel zinc ferrite (soft ferrite) were successfully synthesized by citrate gel combustion technique. They were used to form the composites by mixing them properly in required compositions (x)BaFe12O19-(1−x)Mn0.2Ni0.4Zn0.4Fe2O4 (0 ≤ x ≤ 1). X-ray diffraction (XRD) and scanning electron microscopy (SEM) were utilized to investigate the different structural and morphological parameters of pure and mixed ferrite composites. XRD and SEM results confirmed the coexistence of both phases in the composite material. Moreover, it has been observed that the composites were constituted by nanosized particles. Structure of pure soft ferrite was found to be cubic and that of pure hard ferrite was hexagonal. Dielectric constant (ε′ and ε″) and dielectric loss (tan δ) were analyzed as a function of frequency and composition and the behaviour is explained on the basis of Maxwell-Wagner model. It was observed that the dielectric loss decreases with the increase of hard ferrite content in the composite material. Magnetic measurements suggest the exchange coupling between the magnetizations of soft and hard ferrite grains. It has been observed that the coercivity increases with the increase of the volume of the hard phase in the composite material after an optimal value.
Degradation and passivation of CuInSe2
Authors: Regesch David , Gütay Levent , Larsen Jes K. , Deprédurand Valérie , Tanaka Daisuke , Aida Yasuhiro , Siebentritt Susanne
Published: September 2012

The degradation of CuInSe2 absorbers in ambient air is observed by the decay of the quasi-Fermi level splitting under well defined illumination with time. The decay is faster and stronger in absorbers with [Cu]/[In]<1 than in ones with a higher ratio. It can be attributed to the oxidation of the sample. Epitaxial films containing no Na show very similar trends, indicating that decay and oxidation are independent of the Na content. A standard CdS layer commonly used as buffer in solar cells, terminates the decay even over many months. Aged absorbers can be completely restored by a KCN etch.
Lattice model simulations of the effects of the position of a peptide trigger segment on helix folding and dimerization
Authors: Bhandari Yuba R. , Chapagain Prem P. , Gerstman Bernard S.
Published: September 2012

The folding and dimerization of proteins is greatly facilitated by the presence of a trigger site, a segment of amino acids that has a higher propensity for forming α-helix structure as compared to the rest of the chain. In addition to the helical propensity of each chain, dimerization can also be facilitated by interhelical interactions such as saltbridges, and interfacial contacts of different strengths. In this work, we are interested in understanding the interplay of these interactions in a model peptide system. We investigate how these different interactions influence the kinetics of dimer formation and the stability of the fully formed dimer. We use lattice model computer simulations to investigate how the effectiveness of the trigger segment and its saltbridges depends on the location along the protein primary sequence. For different positions of the trigger segment, heat capacity and free energy of unfolded and folded configurations are calculated to study the thermodynamics of folding and dimerization. The kinetics of the process is investigated by calculating characteristic folding times. The thermodynamic and kinetic data from the simulations combine to show that the dimerization process of the model system is faster when the segment with high helical propensity is located near either end of the peptide, as compared to the middle of the chain. The dependence of the stability of the dimer on the trigger segment's position is also studied. The stability can play a role in the ability of the dimer to perform a biological function that involves partial unzipping. The results on folding and dimer stability provide important insights for designing proteins that involve trigger sites.
AlInP-based rolled-up microtube resonators with colloidal nanocrystals operating in the visible spectral range
Authors: Strelow Ch. , Kietzmann S. , Schramm A. , Seher R. , Penttinen J.-P. , Hakkarainen T. V. , Mews A. , Kipp T.
Published: September 2012

We report on the realization of AlInP rolled-up microtubes that can be used as high refractive index optical resonators operating in the visible spectral range down to a wavelength of at least 530 nm. Furthermore, colloidal CdSe/CdS/ZnS core-shell-shell nanocrystals were deposited close to the microtube wall by fluid filling of the microtube and subsequent evaporation of the solvent. The optical modes of the microtube resonator are excited via coupling of the nanocrystals to the evanescent fields of the modes. By embedding the nanocrystal emitters in a polymer film, an enhanced nanocrystal stability is obtained. The film is studied by the built-in refractometer of the microtube.
Effect of Pd on the Ni2Si stress relaxation during the Ni-silicide formation at low temperature
Authors: Putero M. , Mangelinck D.
Published: September 2012

The thermally induced solid-state reaction between a 50-nm-thick Ni(6%Pd) layer and a Si(100) substrate was investigated using in situ and simultaneous x-ray diffraction and sheet resistance. The reaction begins with the growth of the stressed δ-Ni2Si phase, and the transient θ-Ni2Si. At the end of the θ-Ni2Si consumption, a NiSi seed is formed. Then, the δ-Ni2Si relaxation occurs simultaneously with its subsequent growth and the Pd out diffusion from the unreacted Ni(Pd) layer. It is suggested that the driving force for the Pd diffusion out of the metal layer is linked to both the higher solubility of Pd in NiSi compared to Ni2Si and to the Ni2Si relaxation.
Experimental surface-enhanced Raman scattering response of two-dimensional finite arrays of gold nanopatches
Authors: Grande M. , Bianco G. V. , Vincenti M. A. , Stomeo T. , de Ceglia D. , De Vittorio M. , Petruzzelli V. , Scalora M. , Bruno G. , D'Orazio A.
Published: September 2012

We experimentally investigate the nonlinear response of two-dimensional periodic arrays composed of gold nanopatches on silicon substrate, functionalized by means of a conjugated rigid thiol. The surface-enhanced Raman scattering (SERS) response is empirically evaluated using a laser source operating in the visible spectral range at λ = 633 nm. Nonlinear results are then correlated to optical and structural properties of the samples under investigation. SERS mapping and estimation of the SERS enhancement factor are examined to determine stability and reproducibility of the results, highlighting also the contribution of the plasmonic resonance excited in the two-dimensional periodic array, and the dependence on the numerical aperture of the microscope objective used in the micro-Raman system.
Anomalous metamagnetic-like transition in a FeRh/Fe3Pt interface occurring at T ≈ 120 K in the field-cooled-cooling curves for low magnetic fields
Authors: Salem-Sugui S. , Alvarenga A. D. , Noce R. D. , Guimarães R. B. , Mejia C. Salazar , Salim H. , Gandra F. G.
Published: September 2012

We report on the magnetic properties of a special configuration of a FeRh thin film. An anomalous behavior on the magnetisation vs. temperature was observed when low magnetic fields are applied in the plane of a thin layer of FeRh deposited on ordered Fe3Pt. The anomalous effect resembles a metamagnetic transition and occur only in the field-cooled-cooling magnetisation curve at temperatures near 120 K in samples without any heat treatment.
Assessing the information content of calls of Litoria chloris: quality signalling versus individual recognition
Authors: McLean Morgan J. , Bishop Phillip J. , Hero Jean-Marc , Nakagawa Shinichi
Published: September 2012

In many species, male animals produce costly signals to attract females. Intersexual indicator theories propose that these signals are indicative of male quality, whereas individual recognition models are based on the idea that male signals are used primarily to allow for individual discrimination. These two types of models make differing predictions about the nature of male signals. In particular, these models’ predictions differ in the information about a male’s quality that will be included in his signal, the frequency distributions of male signals in a population, and the ways in which the different traits that make up a signal will covary. Calls from the Australian frog Litoria chloris were tested for consistency with the predictions of intersexual indicator models and individual recognition models. The calls were found to contain minimal information on male quality, and the covariance between different signal traits was consistent with the individual recognition models. However, the frequency distributions of male signal traits agreed with intersexual indicator models. In addition, this study found evidence that the information content of calls may instead mediate intrasexual interactions, although more research is required to determine if this is the case.
Photofragmentation of Isoleucine by Vacuum Ultraviolet Photoionization
Authors: Xie Yang , Cao Lan-lan , Zhang Qiang , Chen Jun , Chu Gen-bai , Zhao Yu-jie , Shan Xiao-bin , Liu Fu-yi , Sheng Liu-si
Published: September 2012

Vacuum ultraviolet photon-induced ionization and dissociation of isoleucine are investigated with synchrotron radiation photoionization mass spectroscopy and theoretical calculations. The main fragment ions at m/z=86, 75, 74, 69, 57, 46, 45, 44, 41, 30, 28, and 18 from isoleucine are observed in the mass spectrum at the photon energy of 13 eV. From the photoionization efficiency curves, appearance energies for the principal fragment ions C5H12N+ (m/z=86), C2H5NO2+ (m/z=75), C5H9+ (m/z=69), C4H9+ (m/z=57), and CH4N+ (m/z=30) are determined to be 8.84±0.07, 9.25±0.06, 10.20±0.12, 9.25±0.10, and 11.05±0.07 eV, respectively, and possible formation pathways are established in detail by the calculations at the B3LYP/6-31++G(d, p) levels. These proposed channels include simple bond cleavage reactions as well as reactions involving intermediates and transition structures. The experimental and computational appearance energies or barriers are in good agreement.
Graphdiyne as Hydrogen Purification Membrane
Authors: Zhao Wen-hui , Yuan Lan-feng , Yang Jin-long
Published: September 2012

The permselectivity of H2/O2, H2/N2, H2/CO, and H2/CH4 mixtures passing a graphdiyne membrane is studied by molecular dynamics simulations. At pressure range of 0.047–4.5 GPa, H2 can pass the graphdiyen membrane quickly, while all the O2, N2, CO, and CH4 molecules are blocked. At pressure of 47 kPa, the hydrogen flow is 7 mol/m2s. With increase of pressure, the hydrogen flow goes up, and reaches maximum of 6×105 mol/m2s at 1.5 GPa. Compared to other known membranes, graphdiyne can be used for means of hydrogen purification with the best balance of high selectivity and high permeance.
Catalytic Transformation of Bio-oil to Olefins with Molecular Sieve Catalysts
Authors: Huang Wei-wei , Gong Fei-yan , Zhai Qi , Li Quan-xin
Published: September 2012

Catalytic conversion of bio-oil into light olefins was performed by a series of molecular sieve catalysts, including HZSM-5, MCM-41, SAPO-34 and Y-zeolite. Based on the light olefins yield and its carbon selectivity, the production of light olefins decreased in the following order: HZSM-5>SAPO-34>MCM-41> Y-zeolite. The highest olefins yield from bio-oil using HZSM-5 catalyst reached 0.22 kg/kgbio-oil with carbon selectivity of 50.7% and a nearly complete bio-oil conversion. The reaction conditions and catalyst characterization were investigated in detail to reveal the relationship between the catalyst structure and the production of olefins. The comparison between the pyrolysis and catalytic pyrolysis of bio-oil was also performed.
Temperature Effect on Hydrogen Evolution Reaction at Au Electrode
Authors: Tang Zhi-qiang , Liao Ling-wen , Zheng Yong-li , Kang Jing , Chen Yan-xia
Published: September 2012

The temperature dependence of hydrogen evolution reaction (HER) at a quasi-single crystalline gold electrode in both 0.1 mol/L HClO4 and 0.1 mol/L KOH solutions was investigated by cyclic voltammetry. HER current displays a clear increase with reaction overpotential (η) and temperature from 278–333 K. In 0.1 mol/L HClO4 the Tafel slopes are found to increases slightly with temperature from 118 mV/dec to 146 mV/dec, while in 0.1 mol/L KOH it is ca. 153±15 mV/dec without clear temperature-dependent trend. The apparent activation energy (Ea) for HER at equilibrium potential is ca. 48 and 34 kJ/mol in 0.1 mol/L HClO4 and 0.1 mol/L KOH, respectively. In acid solution, Ea decreases with increase in η, from Ea=37 kJ/mol (η=0.2 V) to 30 kJ/mol (η=0.35 V). In contrast, in 0.1 mol/L KOH, Ea does not show obvious change with η. The pre-exponential factor (A) in 0.1 mol/L HClO4 is ca. 1 order higher than that in 0.1 mol/L KOH. Toward more negative potential, in 0.1 mol/L HClO4 A changes little with potential, while in 0.1 mol/L KOH it displays a monotonic increase with η. The change trends of the potential-dependent kinetic parameters for HER at Au electrode in 0.1 mol/L HClO4 and that in 0.1 mol/L KOH are discussed.
Influence of Thermal Treatments on In-depth Compositional Uniformity of CuIn(S,Se)2 Thin Films
Authors: Xie Hai-bing , Liu Wei-feng , Jiang Guo-shun , Li Xin-yi , Yan Fei , Zhu Chang-fei
Published: September 2012

CuIn(S,Se)2 thin films were prepared by thermal crystallization of co-sputtered Cu-In alloy precursors in S/Se atmosphere. In-depth compositional uniformity is an important prerequisite for obtaining device-quality CuIn(S,Se)2 absorber thin films. In order to figure out the influence of heat treatments on in-depth composition uniformity of CuIn(S,Se)2 thin films, two kinds of reaction temperature profiles were investigated. One process is “one step profile", referring to formation of CuIn(S,Se)2 thin films just at elevated temperature (e.g. 500 °C). The other is “two step profile", which allows for slow diffusion of S and Se elements into the alloy precursors at a low temperature before the formation and re-crystallization of CuIn(S,Se)2 thin films at higher temperature (e.g. first 250 °C then 500 °C). X-ray diffraction studies reveal that there is a discrepancy in the shape of (112) peak. Samples annealed with “one step profile" have splits on (112) peaks, while samples annealed with “two step profile" have relatively symmetrical (112) peaks. Grazing incident X-ray diffraction and energy dispersive spectrum measurements of samples successively etched in bromine methanol show that CuIn(S,Se)2 thin films have better in-depth composition uniformity after “two step profile" annealing. The reaction mechanism during the two thermal processing was also investigated by X-ray diffraction and Raman spectra.
Absorption and Structural Property of Ethanol/Water Mixture with Carbon Nanotubes
Authors: Du Sheng-ping , Zhao Wen-hui , Yuan Lan-feng
Published: September 2012

Molecular dynamics (MD) simulations are performed to study the structure and adsorption of ethanol/water mixture within carbon nanotubes (CNTs). Inside the (6,6) and (10,10) CNTs, there are always almost full of ethanol molecules and hardly water molecules. Inside wider CNTs, there are some water molecules, while the ethanol mass fractions inside the CNTs are still much higher than the corresponding bulk values. A series of structural analysis for the molecules inside and outside the CNTs are performed, including the distributions of radial, axial, angular density, orientation, and the number of hydrogen bonds. The angular density distribution of the molecules in the first solvation shell outside the CNTs indicates that the methyl groups of ethanol molecules have the strongest interaction with the carbon wall, and are pinned to the centers of the hexagons of the CNTs. Based on the understanding of the microscopic mechanism of these phenomena, we propose that the CNTs prefer to contain ethanol rather than methanol.
Efficient methods for identifying mutated driver pathways in cancer
Authors: Zhao Junfei , Zhang Shihua , Wu Ling-Yun , Zhang Xiang-Sun
Published: September 2012

Motivation: The first step for clinical diagnostics, prognostics and targeted therapeutics of cancer is to comprehensively understand its molecular mechanisms. Large-scale cancer genomics projects are providing a large volume of data about genomic, epigenomic and gene expression aberrations in multiple cancer types. One of the remaining challenges is to identify driver mutations, driver genes and driver pathways promoting cancer proliferation and filter out the unfunctional and passenger ones.

Results: In this study, we propose two methods to solve the so-called maximum weight submatrix problem, which is designed to de novo identify mutated driver pathways from mutation data in cancer. The first one is an exact method that can be helpful for assessing other approximate or/and heuristic algorithms. The second one is a stochastic and flexible method that can be employed to incorporate other types of information to improve the first method. Particularly, we propose an integrative model to combine mutation and expression data. We first apply our methods onto simulated data to show their efficiency. We further apply the proposed methods onto several real biological datasets, such as the mutation profiles of 74 head and neck squamous cell carcinomas samples, 90 glioblastoma tumor samples and 313 ovarian carcinoma samples. The gene expression profiles were also considered for the later two data. The results show that our integrative model can identify more biologically relevant gene sets. We have implemented all these methods and made a package called mutated driver pathway finder, which can be easily used for other researchers.

Availability: A MATLAB package of MDPFinder is available at http://zhangroup.aporc.org/ShiHuaZhang

Contact:  zsh@amss.ac.cn

Supplementary information:  Supplementary data are available at Bioinformatics online.
Magnetovibrio blakemorei gen. nov., sp. nov., a magnetotactic bacterium ( Alphaproteobacteria : Rhodospirillaceae ) isolated from a salt marsh
Authors: Bazylinski Dennis A. , Williams Timothy J. , Lefèvre Christopher T. , Trubitsyn Denis , Fang Jiasong , Beveridge Terrence J. , Moskowitz Bruce M. , Ward Bruce , Schübbe Sabrina , Dubbels Bradley L. , Simpson Brian
Published: September 2012

A magnetotactic bacterium, designated strain MV-1T, was isolated from sulfide-rich sediments in a salt marsh near Boston, MA, USA. Cells of strain MV-1Twere Gram-negative, and vibrioid to helicoid in morphology. Cells were motile by means of a single polar flagellum. The cells appeared to display a transitional state between axial and polar magnetotaxis: cells swam in both directions, but generally had longer excursions in one direction than the other. Cells possessed a single chain of magnetosomes containing truncated hexaoctahedral crystals of magnetite, positioned along the long axis of the cell. Strain MV-1Twas a microaerophile that was also capable of anaerobic growth on some nitrogen oxides. Salinities greater than 10 % seawater were required for growth. Strain MV-1Texhibited chemolithoautotrophic growth on thiosulfate and sulfide with oxygen as the terminal electron acceptor (microaerobic growth) and on thiosulfate using nitrous oxide (N2O) as the terminal electron acceptor (anaerobic growth). Chemo-organoautotrophic and methylotrophic growth was supported by formate under microaerobic conditions. Autotrophic growth occurred via the Calvin–Benson–Bassham cycle. Chemo-organoheterotrophic growth was supported by various organic acids and amino acids, under microaerobic and anaerobic conditions. Optimal growth occurred at pH 7.0 and 26–28 °C. The genome of strain MV-1Tconsisted of a single, circular chromosome, about 3.7 Mb in size, with a G+C content of 52.9–53.5 mol%.Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain MV-1Tbelongs to the familyRhodospirillaceaewithin theAlphaproteobacteria, but is not closely related to the genusMagnetospirillum. The nameMagnetovibrio blakemoreigen. nov., sp. nov. is proposed for strain MV-1T. The type strain ofMagnetovibrio blakemoreiis MV-1T( = ATCC BAA-1436T = DSM 18854T).