bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrathin ultrananocrystalline diamond film synthesis by direct current plasma-assisted chemical vapor deposition
Authors: Lee Hak-Joo , Jeon Hyeongtag , Lee Wook-Seong
Published: October 2011

The synthesis of ultrathin, mirror-smooth, and void-free ultra-nanocrystalline diamond (UNCD) film was investigated using DC-PACVD. The seeding process was investigated in the previously reported “two-step” seeding scheme, where the substrate was pretreated in microwave hydrocarbon plasma prior to the ultrasonic seeding to enhance seed density; in the present study, DC plasma and hot filament process were adopted for the pretreatment, instead of the conventional microwave plasma. Two types of nano-diamond seed powders of similar grain sizes but with different zeta potentials were also compared. The pretreated substrate surface and the synthesized UNCD film were characterized by near edge x-ray absorption fine structure, FTIR, AFM, high-resolution scanning electron microscope, HR-TEM, and Raman spectroscopy. The electrophoretic light scattering spectroscopy was adopted to characterize the zeta potentials of the seeding suspensions and that of the substrates, respectively. Contrary to the previous report, the pretreatments deteriorated the seed density relative to that of the non-treated substrate. By contrast, the seed density was drastically improved by using a proper type of the nano-diamond seed powder. The seed density variation according to the substrate pretreatments and the type of the seed powders was attributed to the relative values of the zeta potentials of the substrates and that of the seed powders, which indicated the electrostatic nature of the seeding process. The variation of the substrate surface zeta potentials was attributed to the variation in the surface terminations induced by the respective pretreatments. The present DC-PACVD environment ensured that the secondary nucleation was also active enough to generate the densely packed UNCD grains in the growth stage. Consequently, the ultrathin, mirror-smooth and void-free UNCD film of 30 nm in thickness was enabled.
Decomposition of pentaerythritol tetranitrate [C(CH2ONO2)4] following electronic excitation
Authors: Yu Zijun , Bernstein Elliot R.
Published: October 2011

We report the experimental and theoretical study of the decomposition of gas phase pentaerythritol tetranitrate (PETN) [C(CH2ONO2)4] following electronic state excitation. PETN has received major attention as an insensitive, high energy explosive; however, the mechanism and dynamics of the decomposition of this material are not clear yet. The initial decomposition mechanism of PETN is explored with nanosecond energy resolved spectroscopy and quantum chemical theory employing the ONIOM algorithm at the complete active space self-consistent field (CASSCF) level. The nitric oxide (NO) molecule is observed as an initial decomposition product from PETN at three UV excitation wavelengths (226, 236, and 248 nm) with a pulse duration of 8 ns. Energies of the three excitation wavelengths coincide with the (0–0), (0–1), and (0–2) vibronic bands of the NO A 2Σ+ ← X 2Π electronic transition, respectively. A unique excitation wavelength independent dissociation channel is observed for PETN, which generates the NO product with a rotationally cold (∼20 K) and a vibrationally hot (∼1300 K) distribution. Potential energy surface calculations at the ONIOM(CASSCF:UFF) level of theory illustrate that conical intersections play an important role in the decomposition mechanism. Electronically excited S1 PETN returns to the ground state through the (S1/S0)CI conical intersection, and undergoes a nitro-nitrite isomerization to generate the NO product.
Dispersion interactions in room-temperature ionic liquids: Results from a non-empirical density functional
Authors: Kohanoff Jorge , Pinilla Carlos , Youngs Tristan G. A. , Artacho Emilio , Soler José M.
Published: October 2011

The role of dispersion or van de Waals (VDW) interactions in imidazolium-based room-temperature ionic liquids is studied within the framework of density functional theory, using a recently developed non-empirical functional [M. Dion, H. Rydberg, E. Schröder, D. C. Langreth, and B. I. Lundqvist, Phys. Rev. Lett. 92, 246401 (2004)10.1103/PhysRevLett.92.246401], as efficiently implemented in the SIESTA code [G. Román-Pérez and J. M. Soler, Phys. Rev. Lett. 103, 096102 (2009)10.1103/PhysRevLett.103.096102]. We present results for the equilibrium structure and lattice parameters of several crystalline phases, finding a general improvement with respect to both the local density (LDA) and the generalized gradient approximations (GGA). Similar to other systems characterized by VDW bonding, such as rare gas and benzene dimers as well as solid argon, equilibrium distances and volumes are consistently overestimated by ≈7%, compared to −11% within LDA and 11% within GGA. The intramolecular geometries are retained, while the intermolecular distances and orientations are significantly improved relative to LDA and GGA. The quality is superior to that achieved with tailor-made empirical VDW corrections ad hoc [M. G. Del Pópolo, C. Pinilla, and P. Ballone, J. Chem. Phys. 126, 144705 (2007)10.1063/1.2715571]. We also analyse the performance of an optimized version of this non-empirical functional, where the screening properties of the exchange have been tuned to reproduce high-level quantum chemical calculations [J. Klimes, D. Bowler, and A. Michaelides, J. Phys.: Condens. Matter 22, 074203 (2010)10.1088/0953-8984/22/7/074203]. The results for solids are even better with volumes and geometries reproduced within 2% of experimental data. We provide some insight into the issue of polymorphism of [bmim][Cl] crystals, and we present results for the geometry and energetics of [bmim][Tf] and [mmim][Cl] neutral and charged clusters, which validate the use of empirical force fields.
A Smoluchowski model of crystallization dynamics of small colloidal clusters
Authors: Beltran-Villegas Daniel J. , Sehgal Ray M. , Maroudas Dimitrios , Ford David M. , Bevan Michael A.
Published: October 2011

We investigate the dynamics of colloidal crystallization in a 32-particle system at a fixed value of interparticle depletion attraction that produces coexisting fluid and solid phases. Free energy landscapes (FELs) and diffusivity landscapes (DLs) are obtained as coefficients of 1D Smoluchowski equations using as order parameters either the radius of gyration or the average crystallinity. FELs and DLs are estimated by fitting the Smoluchowski equations to Brownian dynamics (BD) simulations using either linear fits to locally initiated trajectories or global fits to unbiased trajectories using Bayesian inference. The resulting FELs are compared to Monte Carlo Umbrella Sampling results. The accuracy of the FELs and DLs for modeling colloidal crystallization dynamics is evaluated by comparing mean first-passage times from BD simulations with analytical predictions using the FEL and DL models. While the 1D models accurately capture dynamics near the free energy minimum fluid and crystal configurations, predictions near the transition region are not quantitatively accurate. A preliminary investigation of ensemble averaged 2D order parameter trajectories suggests that 2D models are required to capture crystallization dynamics in the transition region.
Expanded beam deflection method for simultaneous measurement of displacement and vibrations of multiple microcantilevers
Authors: Nieradka K. , Małozięć G. , Kopiec D. , Grabiec P. , Janus P. , Sierakowski A. , Gotszalk T.
Published: October 2011

Here we present an extension of optical beam deflection (OBD) method for measuring displacement and vibrations of an array of microcantilevers. Instead of focusing on the cantilever, the optical beam is either focused above or below the cantilever array, or focused only in the axis parallel to the cantilevers length, allowing a wide optical line to span multiple cantilevers in the array. Each cantilever reflects a part of the incident beam, which is then directed onto a photodiode array detector in a manner allowing distinguishing between individual beams. Each part of reflected beam behaves like a single beam of roughly the same divergence angle in the bending sensing axis as the incident beam. Since sensitivity of the OBD method depends on the divergence angle of deflected beam, high sensitivity is preserved in proposed expanded beam deflection (EBD) method. At the detector, each spot's position is measured at the same time, without time multiplexing of light sources. This provides real simultaneous readout of entire array, unavailable in most of competitive methods, and thus increases time resolution of the measurement. Expanded beam can also span another line of cantilevers allowing monitoring of specially designed two-dimensional arrays. In this paper, we present first results of application of EBD method to cantilever sensors. We show how thermal noise resolution can be easily achieved and combined with thermal noise based resonance frequency measurement.
Non-existence of non-topological solitons in some types of gauge field theories in Minkowski space
Authors: Smolyakov Mikhail N.
Published: October 2011

In this paper the conditions, under which non-topological solitons are absent in the Yang-Mills theory coupled to a nonlinear scalar field in Minkowski space, are obtained in a very simple way. It is also shown that non-topological solitons are absent in the theory describing the massive complex vector field coupled to the electromagnetic field in Minkowski space.
An integrable BC(n) Sutherland model with two types of particles
Authors: Ayadi V. , Fehér L.
Published: October 2011

A hyperbolic BC(n) Sutherland model involving three independent coupling constants that characterize the interactions of two types of particles moving on the half-line is derived by Hamiltonian reduction of the free geodesic motion on the group SU(n, n). The symmetry group underlying the reduction is provided by the direct product of the fixed point subgroups of two commuting involutions of SU(n, n). The derivation implies the integrability of the model and yields a simple algorithm for constructing its solutions.
Stability of shock waves in high temperature plasmas
Authors: Das Madhusmita , Bhattacharya Chandrani , Menon S. V. G.
Published: October 2011

The Dyakov-Kontorovich criteria for spontaneous emission of acoustic waves behind shock fronts are investigated for high temperature aluminum and beryllium plasmas. To this end, the Dyakov and critical stability parameters are calculated from Rankine-Hugoniot curves using a more realistic equation of state (EOS). The cold and ionic contributions to the EOS are obtained via scaled binding energy and mean field theory, respectively. A screened hydrogenic model, including l-splitting, is used to calculate the bound electron contribution to the electronic EOS. The free electron EOS is obtained from Fermi-Dirac statistics. Predictions of the model for ionization curves and shock Hugoniot are found to be in excellent agreement with available experimental and theoretical data. It is observed that the electronic EOS has significant effect on the stability of the planar shock front. While the shock is stable for low temperatures and pressures, instability sets in as temperature rises. The basic reason is ionization of electronic shells and consequent increase in electronic specific heat. The temperatures and densities of the unstable region correspond to those where electronic shells get ionized. With the correct modeling of bound electrons, we find that shock instability for Al occurs at a compression ratio ~5.4, contrary to the value ~3 reported in the literature. Free electrons generated in the ionization process carry energy from the shock front, thereby giving rise to spontaneously emitted waves, which decay the shock front.
Polycrystalline aggregates in the thin-wire configuration
Authors: Xu L. M. , Xie X. M. , Fan H.
Published: October 2011

Polycrystalline thin wire is an important geometric configuration in micro-electro-mechanical system and microelectronic devices. When the cross-sectional dimension is comparable with the grain size, the mechanical properties of the polycrystalline wire are different from those of its bulk counterpart. In the present paper, we use the finite element analysis with statistical concepts to numerically estimate the effective modulus of polycrystalline copper in the thin-wire configuration. As the number of grains in the cross-section increases, the predicted modulus approaches gradually from below to its bulk value. The modulus difference between the thin wire and the bulk material can be as large as 15%.
A four-state magnetoelectric coupling for embedded piezoelectric/magnetic composites
Authors: Fang F. , Xu Y. T. , Zhu W. P. , Yang W.
Published: October 2011

Magnetoelectric (ME) behavior for PZT/Ni composites with PZT embedded in Ni is investigated. The embedded composites show a four-state phenomenon of ME coupling. Upon applied magnetic fields, polarization reversal occurs when the applied static magnetic field exceeds a certain value. Based on the experimental data, a geometric factor k is proposed which captures the size effect on the ME behavior. To quantify the ME behavior of the embedded composites, finite element analysis is performed, which fits well with the experimental data. The calculation enables us to deduce that the four-state ME coupling is related to the change of the compressive force on the contact surfaces between PZT and Ni upon the applied magnetic field. The results are of importance for both the basic understanding of the ME coupling in the embedded PZT/Ni composites and the potential device applications, such as four-state memory devices, magnetic field switches, etc.
Distances of qubit density matrices on Bloch sphere
Authors: Kim Sejong
Published: October 2011

We recall the Einstein velocity addition on the open unit ball \documentclass[12pt]{minimal}\begin{document}$\mathbf {B}$\end{document}B of \documentclass[12pt]{minimal}\begin{document}${\mathbb R}^{3}$\end{document}R3 and its algebraic structure, called the Einstein gyrogroup. We establish an isomorphism between the Einstein gyrogroup on \documentclass[12pt]{minimal}\begin{document}$\mathbf {B}$\end{document}B and the set of all qubit density matrices representing mixed states endowed with an appropriate addition. Our main result establishes a relation between the trace metric for the qubit density matrices and the rapidity metric on the Einstein gyrogroup \documentclass[12pt]{minimal}\begin{document}$\mathbf {B}$\end{document}B.
Controlling the transmission line shape of molecular t-stubs and potential thermoelectric applications
Authors: Stadler Robert , Markussen Troels
Published: October 2011

Asymmetric line shapes can occur in the transmission function describing electron transport in the vicinity of a minimum caused by quantum interference effects. Such asymmetry can be used to increase the thermoelectric efficiency of molecular junctions. So far, however, asymmetric line shapes have been only empirically found for just a few rather complex organic molecules where the origins of the line shapes relation to molecular structure were not resolved. In the present, work we introduce a method to analyze the structure dependence of the asymmetry of interference dips from simple two site tight-binding models, where one site corresponds to a molecular π orbital of the wire and the other to an atomic pz orbital of a side group, which allows us to characterize analytically the peak shape in terms of just two parameters. We assess our scheme with first-principles electron transport calculations for a variety of t-stub molecules and also address their suitability for thermoelectric applications.
Structural characterization of zinc(II) chloride in aqueous solution and in the protic ionic liquid ethyl ammonium nitrate by x-ray absorption spectroscopy
Authors: D’Angelo Paola , Zitolo Andrea , Ceccacci Francesca , Caminiti Ruggero , Aquilanti Giuliana
Published: October 2011

Extended x-ray absorption fine structure (EXAFS) spectroscopy has been used to investigate the species and structures existing in a series of ZnCl2–H2O–NaCl solutions with different chloride/zinc ratios and in a solution of ZnCl2 in the protic ionic liquid ethyl ammonium nitrate (EAN). The average coordination numbers and distances of zinc species were determined from the analysis of the EXAFS data. In aqueous solution the number of chloride ions tightly bounded to Zn2+ is significantly related to the chloride/zinc ratio, and no inner complex formation between Zn2+ and Cl− ions has been detected for low ZnCl2 concentration (0.1 and 0.2 M). Conversely, in the same concentration range (0.13 M) the ZnCl2 species do not dissociate in EAN and the Zn2+ first coordination shell has two chloride ions and is completed by two oxygen atoms of the nitrate anion. The results of this investigation show that notwithstanding the existence of similar characteristics between EAN and water, the solvation properties of the two solvents are markedly different.
A symmetric metamaterial element-based RF biosensor for rapid and label-free detection
Authors: Lee Hee-Jo , Lee Jung-Hyun , Jung Hyo-Il
Published: October 2011

A symmetric metamaterial element-based RF biosensing scheme is experimentally demonstrated by detecting biomolecular binding between a prostate-specific antigen (PSA) and its antibody. The metamaterial element in a high-impedance microstrip line shows an intrinsic S21 resonance having a Q-factor of 55. The frequency shift with PSA concentration, i.e., 100 ng/ml, 10 ng/ml, and 1 ng/ml, is observed and the changes are Δf ≈ 20 MHz, 10 MHz, and 5 MHz, respectively. The proposed biosensor offers advantages of label-free detection, a simple and direct scheme, and cost-efficient fabrication.
Experimental evidence of Ga-vacancy induced room temperature ferromagnetic behavior in GaN films
Authors: Roul Basanta , Rajpalke Mohana K. , Bhat Thirumaleshwara N. , Kumar Mahesh , Kalghatgi A. T. , Krupanidhi S. B. , Kumar Nitesh , Sundaresan A.
Published: October 2011

We have grown Ga deficient GaN epitaxial films on (0001) sapphire substrate by plasma-assisted molecular beam epitaxy and report the experimental evidence of room temperature ferromagnetic behavior. The observed yellow emission peak in room temperature photoluminescence spectra and the peak positioning at 300 cm−1 in Raman spectra confirms the existence of Ga vacancies. The x-ray photoelectron spectroscopic measurements further confirmed the formation of Ga vacancies; since the N/Ga is found to be >1. The ferromagnetism is believed to originate from the polarization of the unpaired 2p electrons of N surrounding the Ga vacancy.
Interaction between Si doping and the polarization-induced internal electric field in the AlGaN/GaN superlattice
Authors: Zhang Wei , Zhang Yue , Xue JunShuai , Zhang Ying , Lv Ling , Zhang JinCheng , Hao Yue
Published: October 2011

AlGaN/GaN superlattices (SLs) with and without Si doping exhibit very different properties. Because of the difference between the dielectric constants of AlGaN and GaN, the wells of the SL are depleted in the undoped structure. With increased Si doping in the GaN wells, the depletion effect will vanish, and the accumulation of electrons will compensate for the polarization-induced internal electric field (PIIEF) in the AlGaN barrier, which is followed by disturbance of the PIIEF in the GaN wells due to electron overflow from the ground state E0 to the first excited state E1. This leads to a decrease in E1-E0.
Comparison of activation energies of laminated lithium-ion secondary cell using LiCoO2 and LiMn2O4 as cathode material by AC impedance method
Authors: Ishikawa Hiroaki , Nishikawa Yuuki , Umeda Minoru
Published: October 2011

In this study, laminated lithium-ion cells were prepared using LiCoO2 or LiMn2O4 for the cathode and graphite carbon for the anode. The electrochemical impedance spectroscopy (EIS) measurements of these cells at elevated temperature (25 °C−60 °C) were carried out to determine the activation energy of the charge/discharge, which is determined from the electrochemical parameters based on an equivalent circuit. Two semicircles were observed at almost all temperatures and the state of charge (SOC) range. For the high frequency semicircle, the activation energy behavior is similar between the LiCoO2-based cell and LiMn2O4-based cell, the highest value was observed at 25% SOC, and the lowest value was observed at 0 and 100% SOCs. On the other hand, for the low frequency semicircle, the behavior of the LiCoO2-based cell is different from that of the LiMn2O4-based cell. The highest value was observed at 50% SOC for the LiCoO2-based cell, and the value was almost the same over the entire SOC range for the LiMn2O4-based cell. At a low frequency, the activation energy of the LiCoO2-based cell was higher than that of the LiMn2O4-based cell over the entire SOC range. Therefore, because cells used for EIS measurements consisted of the same materials except for the cathode material, it is strongly suggested that the semicircle in the high frequency region is mostly caused by the anode reaction and the semicircle in the low frequency region is predominantly caused by the cathode reaction.
Spherical magnetic nanoparticles fabricated by electric explosion of wire
Authors: Kurlyandskaya G. V. , Bhagat S. M. , Safronov A. P. , Beketov I. V. , Larrañaga A.
Published: October 2011

We report the first use of an electrophysical method of electric explosion of wire for preparing magnetic nanoparticles of iron oxide. X-ray diffraction, transmission electron microscopy, magnetization and magnetic resonance measurements were comparatively analyzed. They indicated that the shape of magnetic nanoparticles is close to being spherical. The production order of 100g per hour by this method is advantageous when a large amount of material is needed for applications.
Using metal nanostructures to form hydrocarbons from carbon dioxide, water and sunlight
Authors: Wang Cong , Shen Mengyan , Huo Haibin , Ren Haizhou , Johnson Michael
Published: October 2011

Based on experimental results, we propose a mechanism that allows the use of metal nanostructures to synthesize hydrocarbons and carbohydrates from carbon dioxide, water and sunlight. When sunlight impinges on cobalt nanostructures in a glass chamber, its intensity is greatly enhanced around the tips of the nanostructures through surface plasmon excitations focusing effect, and it then photodissociates the water and carbon dioxide molecules through enhanced photon absorptions of ions around the tips of the nanostructures. The photodissociated molecules in excited states remain on the cobalt nanostructure surfaces and various hydrocarbons and carbohydrates then will be formed around the surfaces at temperatures much lower than 100 oC.
A Density Functional Theory Investigation of the Bimetallic Clusters Nb2Rh and NbRh2 and the Complexes They Form with CO
Authors: Gentleman Alexander S. , Addicoat Matthew A. , Metha Gregory F.
Published: October 2011

The interaction of CO with the bimetallic clusters Nb2Rh and NbRh2 has been theoretically investigated using density functional theory. The lowest energy structure of Nb2Rh is found to be a doublet Cs scalene triangle and the global minimum of Nb2Rh–CO is a dissociative structure with C1 symmetry. The lowest energy minimum of NbRh2 is found to be a doublet C2v isosceles triangle and the global minimum of NbRh2–CO is a dissociative structure with Cs symmetry. In comparison with our previous work on Rh3 + CO (J. Comp. Chem., 2008, 29, 1497), these results show that substitution of a single Rh atom with Nb is sufficient to dissociate CO.
Timeliness of antenatal care for mothers of Aboriginal and non-Aboriginal infants in an urban setting
Authors: Robinson Penelope , Comino Elizabeth , Forbes Andrew , Webster Vana , Knight Jennifer
Published: October 2011

To compare the timing of first hospital antenatal care visit by mothers of Aboriginal and non-Aboriginal infants, and to identify the risk and protective factors associated with timeliness of accessing care, mothers who delivered at Campbelltown hospital between October 2005 and November 2006 were surveyed on the maternity ward. This survey was linked to hospital administrative data. Gestational age at first visit to a hospital-based antenatal clinic was compared for mothers of Aboriginal and non-Aboriginal infants. Risks and protective factors associated with timing of antenatal care were also examined using Cox regression and Kaplan–Meier survival curves. Data on 1520 deliveries were included in this study. Mothers of Aboriginal infants presented slightly later to hospital-based antenatal clinics than mothers of non-Aboriginal infants (median 15.6 weeks versus 14.0 weeks). This difference did not remain after adjustment for all risk and protective factors. The three significant factors remaining were: maternal smoking; not in paid employment; and residence in a disadvantaged suburb. The results may reflect the complex associations that exist between the clustering of disadvantage among families of Aboriginal infants. A multifaceted approach is required to improve the timeliness of hospital-based antenatal care for the mothers of Aboriginal infants.
What influences Australian women to not drink alcohol during pregnancy?
Authors: Jones Sandra C. , Telenta Joanne
Published: October 2011

There is a strong social norm against consuming alcohol during pregnancy. However, many women do not realise they are pregnant until the sixth week and are not provided with information about the risks of consuming alcohol until they visit a health professional in the second trimester. We conducted semi-structured interviews with 12 midwives and 12 pregnant women from two regions in NSW in 2008–09 to explore attitudes towards alcohol consumption during pregnancy, and the factors that may encourage or inhibit women from following the recommendation to abstain from drinking while pregnant. Both groups noted the social issues around pregnant women consuming alcohol due to perceived social norms and the challenges in not revealing early pregnancy status at social events.
Retrotransposition is associated with genome instability during chronological aging
Authors: Maxwell Patrick H. , Burhans William C. , Curcio M. Joan
Published: October 2011

Genetic damage through mutations and genome rearrangements has been hypothesized to contribute to aging. The specific mechanisms responsible for age-induced increases in mutation and chromosome rearrangement frequencies and a potential causative role for DNA damage in aging are under active investigation. Retrotransposons are mobile genetic elements that cause insertion mutations and contribute to genome rearrangements through nonallelic recombination events in humans and other organisms. We have investigated the role of endogenous Ty1 retrotransposons in aging-associated increases in genome instability using the
Saccharomyces cerevisiae
chronological aging model. We show that age-induced increases in loss of heterozygosity and chromosome loss events are consistently diminished by mutations or treatments that reduce Ty1 retrotransposition. Ty1 mobility is elevated in very old yeast populations, and new retromobility events are often associated with chromosome rearrangements. These results reveal a correlation between retrotransposition and genome instability during yeast aging. Retrotransposition may contribute to genetic damage during aging in diverse organisms and provides a useful tool for studying whether genetic damage is a causative factor for aging.
Perceived vulnerabilities of female athletes to the development of disordered eating behaviours
Authors: Stirling Ashley , Kerr Gretchen
Published: October 2011

Disordered eating in athletes is an issue of concern given its prevalence and links with negative health outcomes. The purpose of this study was to examine female athletes’ perceived vulnerabilities to the development of disordered eating. Semi‐structured interviews were conducted with 17 female, competitive athletes from a variety of sports who self‐reported disordered eating behaviours. The results confirm previous research that sport's emphasis on the body and appearance is a factor of vulnerability. Personal qualities of perfectionism, achievement‐motivation, self‐absorption, competitiveness and self‐control, were also described as vulnerabilities to disordered eating behaviours. The participants’ abilities to tolerate pain and to enjoy hunger pains also reportedly increased their vulnerability to disordered eating. It is suggested that the qualities valued by competitive sport may also be potential factors of vulnerability to disordered eating. The findings are discussed in terms of recommendations for future research and practice.
Analysis of the relation between throwing speed and throwing accuracy in team‐handball according to instruction
Authors: García Juan Antonio , Sabido Rafael , Barbado David , Moreno Francisco Javier
Published: October 2011

This study examines the differences between expert and novice team‐handball players in their sensitivity to instructions that emphasize speed or precision requirements. The effects of instructions on throwing speed and accuracy of a handball over arm throw and the speed–accuracy trade‐off in experts and novices is revisited. An expert group (n=18) with a training experience of more than 10 years, and a novice group (n=24) without experience in team‐handball, took part in the study. The participants were asked to throw to targets located at different positions following instructions emphasizing accuracy and instructions emphasizing accuracy and speed. Throwing speed was measured with a speed gun radar, and the centre of the ball when the ball entered the goal was digitalized for accuracy. Under these experimental conditions, the novice group was sensitive to instructions for reducing throwing speed and increasing accuracy when instructions emphasized accuracy. The expert group increased throwing speed when the instructions emphasized speed, but was not less accurate. The results indicate that it is advisable for experts’ speed to be close to maximum speed since it does not seem to have a significant effect on accuracy of the throw.
Optical and plasmonic spectroscopy with cantilever shaped materials
Authors: Tetard L , Passian A , Farahi R H , Davison B H , Lereu A L , Thundat T
Published: October 2011

Micro- and nanocantilevers, which have traditionally played a vital role in the development of force microscopy, and more recently a special role in biological, chemical and physical sensing and detection, have received comparatively little attention in optical spectroscopy. We present an investigation of the optical response of microcantilevers towards their utilization in integrated spectrometers in a broad part of the spectrum. By discussing the overall actuation mechanism we describe how surface modes may effectively contribute to the final signal. Using Fourier transform infrared (FTIR) spectroscopy, a series of multilayered microcantilevers are characterized for their spectral response in the range from 7800 to 400 cm−1. Transmission FTIR and FTIR photothermal spectroscopy are carried out using polystyrene with well-established infrared spectra.
A droplet in the inter-electrode gap during gas metal arc welding
Authors: Nemchinsky Valerian
Published: October 2011

Electrical current flowing through a metallic droplet after its detachment from the wire anode during gas metal arc welding (GMAW) is considered. Although the droplet has much higher electrical conductivity compared with the conductivity of the surrounding plasma, current cannot enter the droplet freely since doing so demands igniting of the cathode spot responsible for electron emission. A new mechanism of current flow through a metallic droplet is suggested: one part of the droplet has a potential, which is slightly below the floating potential; this part of the droplet collects ions from the plasma. The remaining portion of the droplet has a potential difference, which is slightly above the floating one. The latter section collects electrons which recombine with the ions collected by the rest of the droplet's surface. The maximum electric current that can flow through the droplet is estimated. It is shown that this current is on the order of a few tens of amperes.
Behavioural investigation of InN nanodots by surface topographies and phase images
Authors: Deng Qingwen , Wang Xiaoliang , Xiao Hongling , Wang Cuimei , Yin Haibo , Chen Hong , Lin Defeng , Li Jinmin , Wang Zhanguo , Hou Xun
Published: October 2011

We employ surface topographies and phase images to investigate InN nanodots. The samples are annealed at 450, 500 and 550 □. The results reveal that the statistical distributions of number density and mean size depend on annealing ambient. The behaviours of thermal annealing between InN films and InN nanodots are distinguishable: the alloying process of InN and GaN not only occurs in InN platelets, but also in InN nanodots once the samples are annealed at the growth temperature of InN nanodots, while the main change in InN films is the decomposition of InN into In droplets and N2.
Soliton solutions of the mean curvature flow and minimal hypersurfaces
Authors: Hungerbühler Norbert , Mettler Thomas
Published: October 2011

Let(M,g)(M,g)be an oriented Riemannian manifold of dimension at least33andX∈X(M)\mathbf {X} \in \mathfrak {X}(M)a vector field. We show that the Monge-Ampère differential system (M.A.S.) forX\mathbf {X}-pseudosoliton hypersurfaces on(M,g)(M,g)is equivalent to the minimal hypersurface M.A.S. on(M,g¯)(M,\bar {g})for some Riemannian metricg¯\bar {g}if and only ifX\mathbf {X}is the gradient of a functionuu, in which caseg¯=e−2ug\bar {g}=e^{-2u}g. Counterexamples to this equivalence for surfaces are also given.
The hanR/hanI quorum-sensing system of Halomonas anticariensis, a moderately halophilic bacterium
Authors: Tahrioui Ali , Quesada Emilia , Llamas Inmaculada
Published: October 2011

Quorum sensing is a cell density-dependent gene expression mechanism found in many Gram-negative bacteria which involves the production of signal molecules such asN-acylhomoserine lactones (AHLs). One significant group of micro-organisms in which quorum sensing has not been previously studied, however, are the moderate halophiles. We describe here the results of our studies of the quorum-sensing system inHalomonas anticariensisFP35T, which is composed ofluxR/luxIhomologues:hanR(the putative transcriptional regulator gene) andhanI(the autoinducer synthase gene). To understand how thehanR/hanIsystem is organized and regulated we conducted RT-PCR and quantitative real-time PCR assays. Transcriptional analysis indicated that thehanRandhanIgenes are on the same transcript and that their transcription is growth phase-dependent. HanI seems to be the only autoinducer synthase responsible for the synthesis of AHLs by the bacterium, since the inactivation ofhanIresulted in the complete loss of its AHLs. We also found that thehanIgene appears to be transcribed from its own promoter and that its expression does not depend upon HanR. This finding was supported by the fact that the FP35hanRmutant showed AHL-producing activity andhanIexpression similar to that of the wild-type strain, the latter being measured by RT-PCR. Moreover,hanRis expressed from its own promoter and appears to be independent of the AHL signalling molecules produced by HanI.
Metabolic Profiling during Peach Fruit Development and Ripening Reveals the Metabolic Networks That Underpin Each Developmental Stage
Authors: Lombardo Verónica A. , Osorio Sonia , Borsani Julia , Lauxmann Martin A. , Bustamante Claudia A. , Budde Claudio O. , Andreo Carlos S. , Lara María V. , Fernie Alisdair R. , Drincovich María F.
Published: October 2011

Fruit from rosaceous species collectively display a great variety of flavors and textures as well as a generally high content of nutritionally beneficial metabolites. However, relatively little analysis of metabolic networks in rosaceous fruit has been reported. Among rosaceous species, peach (Prunus persica) has stone fruits composed of a juicy mesocarp and lignified endocarp. Here, peach mesocarp metabolic networks were studied across development using metabolomics and analysis of key regulatory enzymes. Principal component analysis of peach metabolic composition revealed clear metabolic shifts from early through late development stages and subsequently during postharvest ripening. Early developmental stages were characterized by a substantial decrease in protein abundance and high levels of bioactive polyphenols and amino acids, which are substrates for the phenylpropanoid and lignin pathways during stone hardening. Sucrose levels showed a large increase during development, reflecting translocation from the leaf, while the importance of galactinol and raffinose is also inferred. Our study further suggests that posttranscriptional mechanisms are key for metabolic regulation at early stages. In contrast to early developmental stages, a decrease in amino acid levels is coupled to an induction of transcripts encoding amino acid and organic acid catabolic enzymes during ripening. These data are consistent with the mobilization of amino acids to support respiration. In addition, sucrose cycling, suggested by the parallel increase of transcripts encoding sucrose degradative and synthetic enzymes, appears to operate during postharvest ripening. When taken together, these data highlight singular metabolic programs for peach development and may allow the identification of key factors related to agronomic traits of this important crop species.
ZDHHC8 knockdown enhances radiosensitivity and suppresses tumor growth in a mesothelioma mouse model
Authors: Sudo Hitomi , Tsuji Atsushi B. , Sugyo Aya , Ogawa Yuriko , Sagara Masashi , Saga Tsuneo
Published: October 2011

Mesothelioma is an aggressive tumor caused by asbestos exposure, the incidence of which is predicted to increase globally. The prognosis of patients with mesothelioma undergoing conventional therapy is poor. Radiation therapy for mesothelioma is of limited use because of the intrinsic radioresistance of tumor cells compared with surrounding normal tissue. Thus, a novel molecular‐targeted radiosensitizing agent that enhances the radiosensitivity of mesothelioma cells is required to improve the therapeutic efficacy of radiation therapy. ZDHHC8 knockdown reduces cell survival and induces an impaired G2/M checkpoint after X‐irradiation in HEK293 cells. In the present study, we further analyzed the effect of the combination of ZDHHC8 knockdown and X‐irradiation and assessed its therapeutic efficacy in mesothelioma models. SiRNA‐induced ZDHHC8 knockdown in 211H and H2052 mesothelioma cells significantly reduced cell survival after X‐irradiation. In 211H cells treated with ZDHHC8 siRNA and X‐irradiation, the G2/M checkpoint was impaired and there was an increase in the number of cells with micronuclei, as well as apoptotic cells, in vitro. In 211H tumor‐bearing mice, ZDHHC8 siRNA and X‐irradiation significantly suppressed tumor growth, whereas ZDHHC8 siRNA alone did not. Immunohistochemical analysis showed decreased cell proliferation and induction of apoptosis in tumors treated with ZDHHC8 siRNA and X‐irradiation, but not with ZDHHC8 siRNA alone. These results suggest that ZDHHC8 knockdown with X‐irradiation induces chromosomal instability and apoptosis through the impaired G2/M checkpoint. In conclusion, the combination of ZDHHC8 siRNA and X‐irradiation has the potential to improve the therapeutic efficacy of radiation therapy for malignant mesothelioma. (Cancer Sci 2012; 103: 203–209)
Analysis of the mating‐type loci of co‐occurring and phylogenetically related species of Ascochyta and Phoma
Authors: WOUDENBERG JOYCE H. C. , DE GRUYTER JOHANNES , CROUS PEDRO W. , ZWIERS LUTE‐HARM
Published: October 2011

Ascochyta and Phoma are fungal genera containing several important plant pathogenic species. These genera are morphologically similar, and recent molecular studies performed to unravel their phylogeny have resulted in the establishment of several new genera within the newly erected Didymellaceae family. An analysis of the structure of fungal mating‐type genes can contribute to a better understanding of the taxonomic relationships of these plant pathogens, and may shed some light on their evolution and on differences in sexual strategy and pathogenicity. We analysed the mating‐type loci of phylogenetically closely related Ascochyta and Phoma species (Phoma clematidina, Didymella vitalbina, Didymella clematidis, Peyronellaea pinodes and Peyronellaea pinodella) that co‐occur on the same hosts, either on Clematis or Pisum. The results confirm that the mating‐type genes provide the information to distinguish between the homothallic Pey. pinodes (formerly Ascochyta pinodes) and the heterothallic Pey. pinodella (formerly Phoma pinodella), and indicate the close phylogenetic relationship between these two species that are part of the disease complex responsible for Ascochyta blight on pea. Furthermore, our analysis of the mating‐type genes of the fungal species responsible for causing wilt of Clematis sp. revealed that the heterothallic D. vitalbina (Phoma anamorph) is more closely related to the homothallic D. clematidis (Ascochyta anamorph) than to the heterothallic P. clematidina. Finally, our results indicate that homothallism in D. clematidis resulted from a single crossover between MAT1‐1 and MAT1‐2 sequences of heterothallic ancestors, whereas a single crossover event followed by an inversion of a fused MAT1/2 locus resulted in homothallism in Pey. pinodes.
Top 10 plant viruses in molecular plant pathology
Authors: SCHOLTHOF KAREN‐BETH G. , ADKINS SCOTT , CZOSNEK HENRYK , PALUKAITIS PETER , JACQUOT EMMANUEL , HOHN THOMAS , HOHN BARBARA , SAUNDERS KEITH , CANDRESSE THIERRY , AHLQUIST PAUL , HEMENWAY CYNTHIA , FOSTER GARY D.
Published: October 2011

Many scientists, if not all, feel that their particular plant virus should appear in any list of the most important plant viruses. However, to our knowledge, no such list exists. The aim of this review was to survey all plant virologists with an association with Molecular Plant Pathology and ask them to nominate which plant viruses they would place in a ‘Top 10’ based on scientific/economic importance. The survey generated more than 250 votes from the international community, and allowed the generation of a Top 10 plant virus list for Molecular Plant Pathology. The Top 10 list includes, in rank order, (1) Tobacco mosaic virus, (2) Tomato spotted wilt virus, (3) Tomato yellow leaf curl virus, (4) Cucumber mosaic virus, (5) Potato virus Y, (6) Cauliflower mosaic virus, (7) African cassava mosaic virus, (8) Plum pox virus, (9) Brome mosaic virus and (10) Potato virus X, with honourable mentions for viruses just missing out on the Top 10, including Citrus tristeza virus, Barley yellow dwarf virus, Potato leafroll virus and Tomato bushy stunt virus. This review article presents a short review on each virus of the Top 10 list and its importance, with the intent of initiating discussion and debate amongst the plant virology community, as well as laying down a benchmark, as it will be interesting to see in future years how perceptions change and which viruses enter and leave the Top 10.
The velvet gene, FgVe1, affects fungal development and positively regulates trichothecene biosynthesis and pathogenicity in Fusarium graminearum
Authors: MERHEJ JAWAD , URBAN MARTIN , DUFRESNE MARIE , HAMMOND‐KOSACK KIM E. , RICHARD‐FORGET FLORENCE , BARREAU CHRISTIAN
Published: October 2011

Trichothecenes are a group of toxic secondary metabolites produced mainly by Fusarium graminearum (teleomorph: Gibberella zeae) during the infection of crop plants, including wheat, maize, barley, oats, rye and rice. Some fungal genes involved in trichothecene biosynthesis have been shown to encode regulatory proteins. However, the global regulation of toxin biosynthesis is still enigmatic. In addition to the production of secondary metabolites belonging to the trichothecene family, F. graminearum produces the red pigment aurofusarin. The gene regulation underlying the production of aurofusarin is not well understood. The velvet gene (veA) is conserved in various genera of filamentous fungi. Recently, the veA gene from Aspergillus nidulans has been shown to be the key component of the velvet complex regulating development and secondary metabolism. Using blast analyses, we identified the velvet gene from F. graminearum, FgVe1. Disruption of FgVe1 causes several phenotypic effects. However, the complementation of this mutant with the FgVe1 gene restores the wild‐type phenotypes. The in vitro phenotypes include hyperbranching of the mycelium, suppression of aerial hyphae formation, reduced hydrophobicity of the mycelium and highly reduced sporulation. Our data also show that FgVe1 modulates the production of the aurofusarin pigment and is essential for the expression of Tri genes and the production of trichothecenes. Pathogenicity studies performed on flowering wheat plants indicate that FgVe1 is a positive regulator of virulence in F. graminearum.
The accuracy of transoesophageal echocardiography in estimating pulmonary capillary wedge pressure in anaesthetised patients
Authors: Ali M. M. , Royse A. G. , Connelly K. , Royse C. F.
Published: October 2011

The objective of this study was to identify whether pulmonary capillary wedge pressure can be estimated in anaesthetised patients receiving mechanical ventilation, using transoesophageal echocardiography. A retrospective validation study investigated a 10‐patient cohort with variable haemodynamic conditions, and a 102‐patient series in which a single measurement was made during stable haemodynamic conditions. Concurrent echocardiographic Doppler and pulmonary artery catheter wedge pressure measurements were performed. In the 10‐patient cohort, the systolic fraction of Doppler measurements in the pulmonary vein (r = −0.32, p = 0.035) and the E/A ratio (r = 0.56, p = 0.0009) were correlated with the wedge pressure. In all cases, the limits of agreement exceeded 10 mmHg, and sensitivity or specificity for detecting wedge pressure ≥ 15 mmHg was poor. This study demonstrates proof of concept that using transoesophageal echocardiography for estimating the pulmonary artery wedge pressure may not be sufficiently accurate for clinical use.