bluuebunny/crossref_metadata_2025 huggingface dataset:
Drugs for Kinetoplastid Diseases – Current Situation and Challenges
Authors: Croft Simon L.
Published: October 2011

The current situation and challenges for treatments for the three human diseases caused by kinetoplastid parasites, leishmaniasis, Chagas disease and human African trypanosomiasis (HAT), are very different. New formulations, therapeutic switching and the potential for combinations of the established drugs, have significantly improved the opportunities for the treatment of visceral leishmaniasis (VL), especially in the Indian subcontinent. However, for HAT, Chagas disease and cutaneous leishmaniases there has been limited progress over the past decade. For the treatment of HAT the only advances over the past two decades have been the demonstrations that an eflornithine/nifurtimox co-administration and a new regime for melarsoprol can shorten treatment duration. Future hopes for the treatment of the CNS stage of this disease are based upon a nitroimidazole, fexinidazole, currently in Phase I clinical studies. A diamidine derivative and an oxoborazole are in the later stages of pre-clinical studies. For Chagas disease, some anti-fungal triazoles, which showed potential in experimental studies over a decade ago, are now moving into clinical studies. Treatments for early chronic and indeterminate infections have been given priority and clinical studies with benznidazole, a drug only previously recommended for acute stage treatment, are in progress. Cutaneous leishmaniasis remains the most neglected disease with little promised.
Children With 7q11.23 Duplication Syndrome: Speech, Language, Cognitive, and Behavioral Characteristics and Their Implications for Intervention
Authors: Velleman Shelley L. , Mervis Carolyn B.
Published: October 2011

7q11.23 duplication syndrome is a recently documented genetic disorder associated with severe speech delay, language delay, a characteristic facies, hypotonia, developmental delay, and social anxiety. Children with this syndrome demonstrate developmentally appropriate nonverbal pragmatic abilities in socially comfortable situations. Motor speech disorder (childhood apraxia of speech and/or dysarthria), oral apraxia, and/or phonological disorder, or symptoms of these disorders, are common, as are characteristics consistent with expressive language disorder. Intensive speech/language therapy is critical for maximizing long-term outcomes.
Quantitative evaluation of loss mechanisms in thin film solar cells using lock-in thermography
Authors: Straube H. , Wagner J.-M. , Schneider J. , Breitenstein O.
Published: October 2011

We describe the measurement and modeling of lock-in thermograms for three differently processed crystalline silicon on glass thin film silicon solar modules. For the purpose of defect impact evaluation, a bias series of lock-in thermograms for a single cell in each module is measured. The resulting images around maximum power point bias show pronounced Peltier heat redistribution inside the cell, which needs to be taken into account for quantitative evaluation of the thermography results. This is done using a finite differences electronics simulation of the current flow inside the module and convolution of the heat distribution patterns with the thermal blurring. The procedure makes it possible to extract relevant cell performance parameters like the area diode dark saturation current and nonlinear edge shunting current densities as well as to evaluate the relative impact of these on the efficiency under simulated illumination.
Nanoindentation and Raman studies of phase-separated Ag-As-S glasses
Authors: Andrikopoulos K. S. , Arvanitidis J. , Dracopoulos V. , Christofilos D. , Wagner T. , Yannopoulos S. N.
Published: October 2011

Nanoindentation is used to study the mechanical properties at the nanoscale of the ternary Agx(As0.33S0.67)100−x glassy system for 0 ≤ x ≤ 25. Direct evidence for phase separation of a Ag-poor and a Ag-rich phase in the composition range 2 ≤ x ≤ 20 is provided. The volume of the Ag-rich phase increases with x and percolates at x ≈ 7. The mechanical properties of the Ag-rich phase are comparable to those of the x = 25 glass, while those of the Ag-poor phase are closer to (however, quite different from) the ones of the base glass AsS2. The structure of both phases at short and medium range order is investigated by micro-Raman spectroscopy and is correlated to their mechanical properties.
Comment on “Reactive force fields for surface chemical reactions: A case study with hydrogen dissociation on Pd surfaces” [J. Chem. Phys. 132, 014704 (2010)]
Authors: Shen X. J. , Dong W. , Xiao Y. , Yan X. H.
Published: October 2011

In a recent paper [Y. Xiao, W. Dong, and H. F. Busnengo, J. Chem. Phys. 132, 014704 (2010)], two of us (Y.X. and W.D.) and H. F. Busnengo reported the parameterization of some reactive force fields (RFF) for describing the dissociative adsorption of H2 on Pd surfaces. They obtained a sufficiently accurate RFF by using the reactive bond order (REBO) formalism of Brenner and showed that the simpler RFF based on the second moment approximation (SMA) failed in giving reliable results. It was concluded that the failure is due to the oversimplified expressions of RFF based on SMA and hence the lack of necessary flexibility. The results of our more recent investigation show that this conclusion needs to be corrected. A more suitable choice of the parameterization conditions allows, in fact, for obtaining a reliable RFF from SMA also.
Relaxation mode analysis of a peptide system: Comparison with principal component analysis
Authors: Mitsutake Ayori , Iijima Hiromitsu , Takano Hiroshi
Published: October 2011

This article reports the first attempt to apply the relaxation mode analysis method to a simulation of a biomolecular system. In biomolecular systems, the principal component analysis is a well-known method for analyzing the static properties of fluctuations of structures obtained by a simulation and classifying the structures into some groups. On the other hand, the relaxation mode analysis has been used to analyze the dynamic properties of homopolymer systems. In this article, a long Monte Carlo simulation of Met-enkephalin in gas phase has been performed. The results are analyzed by the principal component analysis and relaxation mode analysis methods. We compare the results of both methods and show the effectiveness of the relaxation mode analysis.
Magnetic and structural properties of CoCrPt–SiO2-based graded media prepared by ion implantation
Authors: Gaur Nikita , Pandey K. K. M. , Maurer S. L. , Piramanayagam S. N. , Nunes R. W. , Yang H. , Bhatia C. S.
Published: October 2011

The magnetic and structural properties of graded media fabricated by ion implantation of nitrogen (14 N+), oxygen (16O+), and cobalt (59Co+) ions in the CoCrPt–SiO2 recording layer of prototype disk have been studied. Ion implantation of the species was controlled at the atomic scale to fabricate the graded media. Magnetometric measurements indicated that the coercivity was reduced with an increasing dose of the implanted species. The observation of an increase in magnetic domain size has been attributed to the reduction in magnetocrystalline anisotropy energy, which is desirable for achieving graded media. The study indicates that the magnetic properties can be tailored by the appropriate selection of the implantation dose and species.
Assessing weak hydrogen binding on Ca+ centers: An accurate many-body study with large basis sets
Authors: Purwanto Wirawan , Krakauer Henry , Virgus Yudistira , Zhang Shiwei
Published: October 2011

Weak H2 physisorption energies present a significant challenge to even the best correlated theoretical many-body methods. We use the phaseless auxiliary-field quantum Monte Carlo method to accurately predict the binding energy of Ca+– 4H2. Attention has recently focused on this model chemistry to test the reliability of electronic structure methods for H2 binding on dispersed alkaline earth metal centers. A modified Cholesky decomposition is implemented to realize the Hubbard-Stratonovich transformation efficiently with large Gaussian basis sets. We employ the largest correlation-consistent Gaussian type basis sets available, up to cc-pCV5Z for Ca, to accurately extrapolate to the complete basis limit. The calculated potential energy curve exhibits binding with a double-well structure.
Chromospheric anemone jets and magnetic reconnection in partially ionized solar atmosphere
Authors: Singh K. A. P. , Shibata K. , Nishizuka N. , Isobe H.
Published: October 2011

The solar optical telescope onboard Hinode with temporal resolution of less than 5 s and spatial resolution of 150 km has observed the lower solar atmosphere with an unprecedented detail. This has led to many important findings, one of them is the discovery of chromospheric anemone jets in the solar chromosphere. The chromospheric anemone jets are ubiquitous in solar chromosphere and statistical studies show that the typical length, life time and energy of the chromospheric anemone jets are much smaller than the coronal events (e.g., jets/flares/CMEs). Among various observational parameters, the apparent length and maximum velocity shows good correlation. The velocity of chromospheric anemone jets is comparable to the local Alfvén speed in the lower solar chromosphere. Since the discovery of chromospheric anemone jets by Hinode, several evidences of magnetic reconnection in chromospheric anemone jets have been found and these observations are summarized in this paper. These observations clearly suggest that reconnection occurs quite rapidly as well as intermittently in the solar chromosphere. In the solar corona (λi > δSP), anomalous resistivity arises due to various collisionless processes. Previous MHD simulations show that reconnection becomes fast as well as strongly time-dependent due to anomalous resistivity. Such processes would not arise in the solar chromosphere which is fully collisional and partially-ionized. So, it is unclear how the rapid and strongly time-dependent reconnection would occur in the solar chromosphere. It is quite likely that the Hall and ambipolar diffusion are present in the solar chromosphere and they could play an important role in driving such rapid, strongly time-dependent reconnection in the solar chromosphere.
Plasma-beta dependence of the fast reconnection mechanism in an initially force-free current sheet
Authors: Ugai M.
Published: October 2011

The present paper systematically studies the spontaneous fast reconnection mechanism in an initially force-free current sheet in a wide range of plasma beta (β); in our previous work it was studied for a special case of β = 0.15. In each case, the evolution as well as the resulting structure of the fast reconnection is qualitatively similar to the one that was already reported for the case of β = 0.15. Quantitatively, the fast reconnection evolution becomes more rapid and drastic for the lower plasma beta. For the cases of very low plasma beta (β = 0.01 or 0.02), the plasma temperature is extremely enhanced to the value almost 1/β times larger than its initial value in the resulting fast reconnection jet and large-scale plasmoid regions. Once the fast reconnection mechanism is ignited in a local spot-like region, its basic structure eventually established is sustained almost steadily, giving rise to the plasmoid swelling with time and propagating outwards. Accordingly, the characteristic reconnection regions, where plasma thermodynamic quantities are remarkably enhanced, rapidly expand in all (x, y, and z) directions in Alfven time scales, which may be responsible for the explosive expansion of large flares as well as for the distinct plasma heating observed in the solar corona.
Continuous-time photon-stimulated desorption spectroscopy studies on soft x-ray-induced reactions of CF3Br adsorbed on Si(111)-7×7
Authors: Tsai W.-C. , Wang S.-K. , He T.-M. , Chou L.-C. , Hsieh Y.-C. , Liao K.-Y. , Chen H.-C. , Wen C.-R.
Published: October 2011

Continuous-time core-level photon-stimulated desorption (PSD) spectroscopy was used to study the soft x-ray-induced reactions of CF3Br molecules adsorbed on Si(111)-7×7 near the Si(2p) edge (98–110 eV). The monochromatic synchrotron radiation was employed as a soft x-ray light source in the photon-induced reactions and also as a probe for investigating the produced fluorination states of the bonding surface Si atom in the positive-ion PSD spectroscopy. Several different surface coverages were investigated. The PSD spectra from the low-CF3Br-covered surfaces show the production of surface SiF species, while those from the high-CF3Br-covered surfaces depict the formation of surface SiF, SiF2, and SiF3 species. The photolysis cross section of the submonolayer CF3Br-covered surface is determined as ∼4.3×10−18 cm2. A comparison with the results on CF3Cl/Si(111)-7×7 surface is discussed.
Control of oxygen delamination in solid oxide electrolyzer cells via modifying operational regime
Authors: Rashkeev Sergey N. , Glazoff Michael V.
Published: October 2011

Modifications of operational regimes for solid oxide electrolyzer cell (SOEC) devices for hydrogen production are discussed. It is shown that applying alternating current voltage pulses at a certain frequency range to SOECs could reduce oxygen delamination degradation in these devices and significantly increase their lifetime. This operational scheme provides possibility to increase longevity of SOEC devices required for their use in commercial hydrogen production processes, without any significant modification of used materials and/or cell design.
An accurate new method to measure the dimensionless figure of merit of thermoelectric devices based on the complex impedance porcupine diagram
Authors: De Marchi Andrea , Giaretto Valter
Published: October 2011

The heat diffusion related f−1/2 slow decay in the frequency domain transfer function of thermoelectric devices introduces a bias in figure of merit measurement methods that do not take it into account. The bias can range from less than 1% to more than 20% depending on the device. Harman type methods are not immune. Neither is the simple single measurement procedure proposed here on the basis of a complex thermal impedance analysis of the device, but in this case the supporting theory allows evaluating and correcting for the bias with documented accuracy. To this aim, both a theoretical approach based on a priori knowledge of the device and an experimental one based on theory guided measurements are possible and are described in the paper. Typical residual Type B uncertainties after correction can be below 10% of the bias.
A generalized analytical compliance model for transversely symmetric three-segment flexure hinges
Authors: Lobontiu Nicolae , Cullin Matt , Ali Muhammad , Brock Jennifer McFerran
Published: October 2011

This paper presents a generalized compliance model for a three-segment notch flexure hinge with transverse symmetry. This flexure hinge configuration is most frequently employed in planar-motion, small-displacement compliant mechanisms. The axial and bending compliances are derived for this flexure hinge based on the compliances of two flexure components. The derivation is generalized such that it can be applied to various segment geometries. Using this open-ended model, a three-segment right elliptical corner-filleted flexure hinge design was analyzed. This geometric configuration introduces additional geometric parameters, which can be used to optimize the compliance of the flexure hinge without modifying its gross dimensions. The results of the analysis were validated in part by modifying the geometric parameters of the center segment and elliptical corner fillets to form limiting cases corresponding to several previously investigated configurations, namely right elliptical, three-segment right circular corner-filleted, and right circular geometries. Finite element analysis simulation and experimental testing were used to further validate the three-segment right elliptical corner-filleted analytical model. Additional simulations based on the analytical model were performed to highlight the influence of geometric parameters on compliances and to investigate shear effects for short flexure hinges.
Counter-polarized single-photon generation from the auxiliary cavity of a weakly nonlinear photonic molecule
Authors: Bamba Motoaki , Ciuti Cristiano
Published: October 2011

We propose a scheme for the resonant generation of counter-polarized single photons in double asymmetric cavities with a small Kerr optical nonlinearity (as that created by a semiconductor quantum well) compared to the mode broadening. Due to the interplay between spatial intercavity tunneling and polarization coupling, by weakly exciting with circularly polarized light one of the cavities, we predict strong antibunching of counter-polarized light emission from the non-pumped auxiliary cavity. This scheme due to quantum interference is robust against surface scattering of pumping light, which can be suppressed both by spatial and polarization filters.
Enhanced magnetoimpedance and field sensitivity in microstructure controlled FeSiCuNbB ribbons
Authors: Sahoo Trilochan , Chandra Mishra Amaresh , Srinivas V. , Nath T. K. , Srinivas M. , Majumdar B.
Published: October 2011

Fe73.5Si13.5Cu1Nb3B9 and Fe77.2Si11.2Cu0.8Nb3.3B7.5 nanocomposite materials consisting of nanocrystalline phase in an amorphous matrix were obtained by heat-treatment of their precursor amorphous ribbons. The influence of structural modifications induced during the heat-treatment on soft magnetic properties and magnetoimpedance (MI) effect have been studied. The structural investigations on both these ribbons revealed the presence of two phases, fine grained Fe3Si phase and a residual amorphous phase on heat-treatment. The maximum MI ratio obtained in the present study is 95% at f = 4 MHz, for the optimized heat-treated Fe77.2Si11.2Cu0.8Nb3.3B7.5 ribbon. This is ascribed to the increase in magnetic permeability and decrease in coercive force and intrinsic resistivity. Moreover, a maximum magnetic field sensitivity (ξ) of 8.3%/Oe at f = 2.5 MHz is obtained, for the optimized nanocrystalline Fe73.5Si13.5Cu1Nb3B9 ribbon. This suggests that tailoring of the nanocrystalline microstructures induced by optimum heat-treatment conditions can result in obtaining excellent combinations of the magnetic permeability and resistivity. Our results indicate that these Fe-based nanocrystalline materials can be ideally used for low magnetic field and high frequency sensor applications.
Point defects in gallium nitride: X-ray absorption measurements and multiple scattering simulations
Authors: Peter Robert , Segota Doris , Petravic Mladen
Published: October 2011

We have studied the formation of nitrogen-related point defects in gallium nitride (GaN) using near-edge x-ray absorption fine-structure (NEXAFS) spectroscopy and ab initio FEFF calculations. The presence of several point defects, created within the GaN matrix by low-energy ion-bombardment, has been detected by NEXAFS measurements around N K-edge. FEFF simulations that take into account the formation of nitrogen antisites, interstitials, and vacancies around absorbing nitrogen atoms are consistent with NEXAFS results. The position of energy levels created by these defects within the energy gap of GaN, obtained by both NEXAFS measurements and FEFF simulations, are in good agreement with theoretical predictions.
Determining graphene adhesion via substrate-regulated morphology of graphene
Authors: Zhang Zhao , Li Teng
Published: October 2011

Understanding the adhesion between graphene and other materials is crucial for achieving more reliable graphene-based applications in electronic devices and nanocomposites. The ultra-thin profile of graphene, however, poses a significant challenge to direct measurement of its adhesion property using conventional approaches. We show that there is a strong correlation between the morphology of graphene on a compliant substrate with patterned surface and the graphene-substrate adhesion. We establish an analytic model to quantitatively determine such a strong correlation. Results show that, depending on the graphene-substrate adhesion, number of graphene layers, and substrate stiffness, graphene exhibits two distinct types of morphology: (I) graphene remains bonded to the substrate and corrugates to an amplitude up to that of the substrate surface patterns; (II) graphene debonds from the substrate and remains flat on top of the substrate surface patterns. The sharp transition between these two types of graphene morphology occurs at a critical adhesion between the graphene and the compliant substrate material. These results potentially open up a feasible pathway to measuring the adhesion property of graphene.
Observation of plasma array dynamics in 110 GHz millimeter-wave air breakdown
Authors: Cook Alan M. , Hummelt Jason S. , Shapiro Michael A. , Temkin Richard J.
Published: October 2011

We present dynamical measurements of self-organizing arrays of plasma structures in air induced by a 110 GHz millimeter-wave beam with linear or circular polarization. The formation of the individual plasmas and the growth of the array pattern are studied using a fast-gated (5–10 ns) intensified camera. We measure the time-dependent speed at which the array pattern propagates in discrete steps toward the millimeter-wave source, observing a peak speed greater than 100 km/s. We observe the expansion of an initially spherical plasma into a disk or an elongated filament, depending on the polarization of the incident beam. The results show good agreement with one-dimensional ionization-diffusion theory and two-dimensional simulations.
A coupled analysis of the piezoresponse force microscopy signals
Authors: Wang J. H. , Chen C. Q.
Published: October 2011

We present a coupled theory on the piezoresponse force microscopy (PFM) responses by solving the electromechanical equations for transversally isotropic piezoelectric materials. The effective piezoelectric coefficients calculated from the coupled, the decoupled, and the indentation theories are then compared with the true piezoelectric coefficient d33. An approximately linear relationship between the effective piezoelectric coefficient from the coupled PFM analysis and d33 is obtained. Finally, the coupled analysis is extended to the piezoelectric film/substrate system. The obtained results are believed to be useful in quantitatively interpreting the PFM signals.
Determination of internal parameters for AlGaN-cladding-free m-plane InGaN/GaN laser diodes
Authors: Farrell R. M. , Haeger D. A. , Hsu P. S. , Fujito K. , Feezell D. F. , DenBaars S. P. , Speck J. S. , Nakamura S.
Published: October 2011

The dependence of device characteristics on cavity length is used to determine the injection efficiency, internal loss, and material gain of electrically injected AlGaN-cladding-free m-plane InGaN/GaN laser diodes. Estimates for the transparency carrier density are discussed in the context of recombination coefficients that have been reported for c-plane InGaN-based light-emitting devices.
Three Novel Polymeric CoII/CuII Complexes Assembled from 5-Nitro-1,2,3-benzenetricarboxylate and 4,4'-Bipyridine: Syntheses, Crystal Structures, and Magnetic Properties
Authors: Zhu Xiaofei , Wang Ning , Luo Yuhui , Pang Yu , Tian Dan , Zhang Hong
Published: October 2011

To investigate the coordination behaviour of tricarboxylate ligands that always induced the formation of intriguing metal organic frameworks, three CoII/CuII complexes constructed with bi-/tri-nuclear secondary building units (SBUs), namely CoII3(O2N-btc)2(4,4′-bpy)3(H2O)2 (1), [CuII3(O2N-btc)2(4,4′-bpy)2(H2O)2]·2H2O(2) and [CuII5(O2N-btc)2(O2N-btcH)2(4,4′-bpy)2(μ2 -OH2)2(H2O)8]·4H2O(3) (O2N-btcH3 = 5-nitro-1,2,3-benzenetricarboxylate, 4,4′-bpy = 4,4-bipyridyl), were hydrothermally synthesized using O2N-btcH3 and 4,4′-bpy as ligands. Complexes 1 and 2 exhibit the 3D framework constructed from a binuclear [M2(COO)2] (M = CuII and CoII) unit and a mononuclear MII unit, displaying (4·6·8)2(64·82) (42·68·83·102) and (4·6·8)2(62·84) (42·62·810·12) topology, respectively. Complex 3 displays an interesting 2D ladder-layered network constructed from a trinuclear [Cu3(μ2-OH2)2] unit and a mononuclear CuII unit as the linking nodes, showing (42.6)2(46.66.83) nets. These compounds are well characterized by elemental analysis, FTIR, thermogravimetric analysis and powder X–ray diffraction. The direct current magnetic susceptibility measurements were carried out to study their magnetic properties.
A Series of 2D and 3D Novel Lanthanide Complexes Constructed from Squarate C4O42–: Syntheses, Structures, Magnetic Properties, and Near-infrared Emission Properties
Authors: Wang Li , Gu Wen , Deng Xiu-Jun , Zeng Ling-Fei , Liao Sheng-Yun , Zhang Ming , Yang Lin-Yan , Liu Xin
Published: October 2011

The solvothermal combination of trivalent lanthanide metal precursors with a squarate ligand (H2C4O4, 3,4-dihydroxy-3-cyclobutene-1,2-dione) has afforded the preparation of a family of eight new coordination polymers, [Ln2(C4O4)3(H2O)4] (Ln = La–Nd, Ho) (1–5), [Ln2(C4O4)3(H2O)8] (Ln = Er, Dy) (6, 7), and Tb2(C4O4)2(C2O4)(H2O)4 (8). Structural analysis reveals that the squarate ligand displays versatile coordination modes to generate novel 2D and 3D frameworks. Three new coordination modes, a bidentate/monodentate μ3 and two bidentate/monodentate μ4 coordination modes, are first reported. In addition, the variable-temperature magnetic properties of the Pr, Nd, Ho, Dy, and Tb complexes, the solid-state near-infrared luminescence spectra of the Pr, Nd, Ho, and Er complexes, and their thermogravimetric analyses are discussed.
Molecular Photodiode and Two-channel Optoelectronic Demultiplexer based on the [60]Fullerene-porphyrin Tetrad
Authors: Lewandowska Kornelia , Szaciłowski Konrad
Published: October 2011

Photoelectrodes containing Langmuir–Blodget layers of [60]fullerene-porphyrin tetrad behave like photodiodes. Upon excitation within the whole absorption spectrum of the molecule they generate photocurrent, the direction of which depends on the conducting substrate potential. At negative polarization high intensity cathodic photocurrent are observed, while at positive polarization much weaker anodic photocurrents are observed. The forward-bias to reverse-bias current ratio amounts 5:1. Therefore the [60]fullerene-porphyrin tetrad is closely related to semiconductors showing photoelectrochemical photocurrent switching effect and is a promising material for molecular optoelectronics. It can be used as a simple molecular photodiode. Assignment of logic values to polarization of the photoelectrode and to light and photocurrent pulses results in a very efficient two-channel optoelectronic demultiplexer.
Cyclizations using Selenium Chemistry for Substituted 3-Hydroxypiperidines and 3-Hydroxypyrrolidines
Authors: Cooper Matthew A. , Ward A. David
Published: October 2011

The development of new methods for the stereoselective synthesis of nitrogen heterocycles is of current interest because of increasing demands for the syntheses of biologically important alkaloids and related compounds. It is shown that selenium-induced cyclization of 4-hydroxy-5-pentenylamines occurs regio- and stereo-selectively to afford cis-3-hydroxy-2-phenylselenomethylpyrrolidines, whereas 5-hydroxy-6-hexenylamines cyclize and give trans-3-hydroxy-2-phenylselenomethylpiperidines, with some compounds forming stable hydrates. In all cases cyclization proceeds regioselectively to give only the exo adducts with moderate to good diastereoselectivity. The reaction appeared to be under kinetic control as product ratios did not alter with time and the separated diastereomers did not interconvert when resubjected to the reaction conditions. These phenylseleno-substituted compounds could be transformed to diols by substitution of the corresponding selenone with a hydroxide ion. Substituted pyrrolidines and piperidines were thus afforded from unsaturated protected amines by electrophilic activation with SeII, followed by oxidation of the intermediate to SeVI and substitution with nucleophiles.
Constructive Embedding
Authors: Langler Richard F.
Published: October 2011

The application of perturbational expressions to the development of a novel set of approaches to embedding, i.e. constructive embedding, is presented. The most powerful of these approaches begins by exploiting the recently-recognized, free-electron-model-derived method for rapidly enumerating all possible embeddings for unbranched polyenes or polyenyls. Thereafter, one can employ constructive elaboration of new molecules which will have known embeddability.
Structural Chemistry of [MX2(bipy)] (M=Pd, Pt; X=Cl, Br, I): the Yellow Polymorph of Dichlorido(2,2'-bipyridine)platinum(II) and Diiodido(2,2'-bipyridine)palladium(II), and Overview of this System
Authors: Canty Allan J. , Gardiner Michael G. , Jones Roderick C. , Sharma Manab
Published: October 2011

Synchrotron data have been used to determine the structures of the yellow polymorph of dichlorido(2,2′-bipyridine)platinum(ii) (1), and diiodido(2,2′-bipyridine)palladium(ii) (2), allowing a detailed comparison of the crystal chemistry of [MX2(bipy)] (M = Pd, Pt; X = Cl, Br, I), which exhibit polymorphism involving nine structures distributed over five space groups. Complex 1 crystallizes in space group Pbca (a = 18.2540(7), b = 15.6970(7), c = 7.3560(6) Å), and 2 in space group C2/c (a = 17.149(1), b = 9.8050(8), c = 7.548(1) Å, β = 110.72(1) °).
Ion Translocation in Artificial Molecule-based Systems Induced by Light, Electrons, or Chemicals
Authors: Bofinger Robin , Ducrot Aurélien , Jonusauskaite Laura , McClenaghan Nathan D. , Pozzo Jean-Luc , Sevez Guillaume , Vives Guillaume
Published: October 2011

Synthetic molecules and nanodevices, like their more elaborate biological counterparts, have been shown to perform several sophisticated functions, using even fairly simple molecular architectures. One limitation to developing artificial molecular arrays and networks from these miniscule building blocks is the lack of a unifying strategy whereby they can communicate or interact together, which has been successfully developed in natural systems. Understanding and harnessing these efficient biological processes could prove key in the development of future integrated molecule-based nanodevices and networks. Herein, we give a short overview of some manifestations of intra- and intermolecular communication based on chemical messengers in artificial systems, in some ways analogous to natural systems, which are in turn controlled by light, a redox process or a chemical reaction or interaction. Some advantages, limitations, and challenges are highlighted.
Glucocorticoid receptors in the prefrontal cortex regulate stress-evoked dopamine efflux and aspects of executive function
Authors: Butts Kelly A. , Weinberg Joanne , Young Allan H. , Phillips Anthony G.
Published: October 2011

Enhanced dopamine efflux in the prefrontal cortex is a well-documented response to acute stress. However, the underlying mechanism(s) for this response is unknown. Using in vivo microdialysis, we demonstrate that blocking glucocorticoid receptors locally within the rat prefrontal cortex results in a reduction in stress-evoked dopamine efflux. In contrast, blocking glucocorticoid receptors in the ventral tegmental area did not affect stress-evoked dopamine efflux in the prefrontal cortex. Additionally, local administration of corticosterone into the prefrontal cortex increased prefrontal dopamine efflux. The functional impact of enhanced dopamine efflux evoked by acute stress was demonstrated using a cognitive task dependent on the prefrontal cortex and sensitive to impairment in working memory. Notably, stress-induced impairments in cognition were attenuated by blockade of glucocorticoid receptors in the prefrontal cortex. Taken together, these data demonstrate that glucocorticoids act locally within the prefrontal cortex to modulate mesocortical dopamine efflux leading to the cognitive impairments observed during acute stress.
A pair of co-opted retroviral envelope
syncytin
genes is required for formation of the two-layered murine placental syncytiotrophoblast
Authors: Dupressoir Anne , Vernochet Cécile , Harper Francis , Guégan Justine , Dessen Philippe , Pierron Gérard , Heidmann Thierry
Published: October 2011

In most mammalian species, a critical step of placenta development is the fusion of trophoblast cells into a multinucleated syncytiotrophoblast layer fulfilling essential fetomaternal exchange functions. Key insights into this process came from the discovery of envelope genes of retroviral origin, the
syncytins
, independently acquired by the human (
syncytin-1
and -
2
), mouse (
syncytin-A
and -
B
), and rabbit (
syncytin-Ory1
) genomes, with fusogenic properties and placenta-specific expression. We previously showed that mouse
syncytin-A
is essential for the formation of one of the two syncytiotrophoblast layers and for embryo survival. Here, we have generated
syncytin-B
KO mice and demonstrate that
syncytin-B
null placenta displays impaired formation of syncytiotrophoblast layer II (ST-II), with evidence of unfused apposed cells, and enlargement of maternal lacunae disrupting the placenta architecture. Unexpectedly,
syncytin-B
null embryos are viable, with only limited late-onset growth retardation and reduced neonate number. Microarray analyses identified up-regulation of the
connexin 30
gene in mutant placentae, with the protein localized at the fetomaternal interface, suggesting gap junction-mediated compensatory mechanisms. Finally, double-KO mice demonstrate premature death of
syncytin-A
null embryos if
syncytin-B
is deleted, indicating cooperation between ST-I and ST-II. These findings establish that both endogenous retrovirus-derived
syncytin
genes contribute independently to the formation of the two syncytiotrophoblast layers during placenta formation, demonstrating a major role of retroviral gene capture, through convergent evolution, to generate multiple placental structures. Although some are absolutely required for completion of pregnancy, others are still amenable to “epigenetic” compensations, thus illustrating the complexity of the molecular machinery that developed during placental evolution.
Culture, individual differences, and situation: Influence on coping in French and Chinese table tennis players
Authors: Laborde Sylvain , You Min , Dosseville Fabrice , Salinas Agnès
Published: October 2011

The aim of the present study was to explore the influence of culture, individual differences (i.e. trait emotional intelligence), and given situations on coping behaviours. The trait emotional intelligence of table tennis players (French, n=58; Chinese, n=53) was evaluated using the Trait Emotional Intelligence Questionnaire, while their use of coping strategies [task‐oriented coping (TOC) and disengagement‐oriented coping (DOC)] was assessed according to three stressful situations. There was a main effect of culture (η2 p = 0.28, P<0.001 for TOC and η2 p = 0.25, P<0.001 for DOC), trait emotional intelligence (η2 p = 0.05, P<0.001 for TOC and η2 p = 0.04, P<0.001 for DOC), and situation (η2 p = 0.06, P<0.001 for DOC) on coping. From a theoretical and applied point of view, our results indicate the need to take account of these three to understand and provide appropriate support for coping.
Justifying anti‐doping: The fair opportunity principle and the biology of performance enhancement
Authors: Loland Sigmund , Hoppeler Hans
Published: October 2011

Doping is a complex moral and scientific dilemma and its prevention has led to a costly but less than perfect control system implemented worldwide by the World Anti‐doping Agency (WADA). For a substance or method to be considered for the WADA Prohibited List, three criteria must be met: (1) the substance or method has the potential to enhance, or enhances, sport performance; (2) use of the substance or method represents an actual or potential health risk to the athlete; and (3) use of the substance or method violates the “spirit of sport”. The “spirit of sport” is defined as “the celebration of the human spirit, body and mind” and explained with reference to a series of ideal values: ethics, fair play, and honesty; health; excellence in performance; character and education; fun and enjoyment; teamwork; dedication and commitment; respect for rules and laws; respect for self and other participants; courage; community and solidarity. These values do not lend themselves to clear‐cut interpretation and are of little help in drawing unambiguous lines in concrete cases. A proposal is made of how to interpret the “spirit of sport” in more precise ways in terms of a combination of the fair opportunity principle and a biological and evolutionary understanding of athletic performance as a result of the systematic utilization of the phenotypic plasticity of the human organism. The argument is that such understanding improves significantly the possibilities for drawing of lines when it comes to doping issues.
Gate bias stress stability under light irradiation for indium zinc oxide thin-film transistors based on anodic aluminium oxide gate dielectrics
Authors: Li Min , Lan Linfeng , Xu Miao , Wang Lei , Xu Hua , Luo Dongxiang , Zou Jianhua , Tao Hong , Yao Rihui , Peng Junbiao
Published: October 2011

Thin-film transistors (TFTs) using indium zinc oxide as the active layer and anodic aluminium oxide (Al2O3) as the gate dielectric layer were fabricated. The device showed an electron mobility of as high as 10.1 cm2 V−1 s−1, an on/off current ratio of as high as ∼108, and a turn-on voltage (V
on) of only −0.5 V. Furthermore, this kind of TFTs was very stable under positive bias illumination stress. However, when the device experienced negative bias illumination stress, the threshold voltage shifted to the positive direction. It was found that the instability under negative bias illumination stress (NBIS) was due to the electrons from the Al gate trapping into the Al2O3 dielectric when exposed to the illuminated light. Using a stacked structure of Al2O3/SiO2 dielectrics, the device became more stable under NBIS.
Probing background ionization: positive streamers with varying pulse repetition rate and with a radioactive admixture
Authors: Nijdam S , Wormeester G , van Veldhuizen E M , Ebert U
Published: October 2011

Positive streamers need a source of free electrons ahead of them to propagate. A streamer can supply these electrons by itself through photo-ionization, or the electrons can be present due to external background ionization. Here we investigate the effects of background ionization on streamer propagation and morphology by changing the gas composition and the repetition rate of the voltage pulses, and by adding a small amount of radioactive 85Kr.

We find that the general morphology of a positive streamer discharge in high-purity nitrogen depends on background ionization: at lower background ionization levels the streamers branch more and have a more feather-like appearance. This is observed both when varying the repetition rate and when adding 85Kr, though side branches are longer with the radioactive admixture. But velocities and minimal diameters of streamers are virtually independent of the background ionization level. In air, the inception cloud breaks up into streamers at a smaller radius when the repetition rate and therefore the background ionization level is higher. When measuring the effects of the pulse repetition rate and of the radioactive admixture on the discharge morphology, we found that our estimates of background ionization levels are consistent with these observations; this gives confidence in the estimates.

Streamer channels generally do not follow the paths of previous discharge channels for repetition rates of up to 10 Hz. We estimate the effect of recombination and diffusion of ions and free electrons from the previous discharge and conclude that the old trail has largely disappeared at the moment of the next voltage pulse; therefore the next streamers indeed cannot follow the old trail.
A novel method of using the OES line ratio to determine the spatially resolved atomic density in low-temperature plasmas and its application in carbon and aluminium atoms in capacitively coupled plasmas
Authors: Li Jiang , Zhu Xi-Ming , Pu Yi-Kang
Published: October 2011

A new optical emission spectroscopy (OES) line-ratio method is proposed to obtain spatially resolved atomic densities in low-temperature plasmas. Since the line ratio of two emission lines from the same upper level depends on the atomic densities in the lower levels due to radiation trapping, the spatially resolved atomic densities in the lower levels can be obtained from the relevant line ratios when a so-called mono-directional escape factor is used. The spatially resolved atomic densities of carbon atom in a CF4 plasma and aluminium atom in an argon plasma are obtained using this method. According to their spatial profile, the production and loss mechanisms of these atoms are discussed.
Healing of magnetic islands in stellarators by plasma flow
Authors: Hegna C.C.
Published: October 2011

Recent experiments from the Large Helical Device indicate that plasma flow can play a primary role in ‘healing’ vacuum magnetic islands in stellarators. The observed elimination of magnetic islands tends to occur at low collisionality and high plasma β. A model explaining this phenomenon is developed reminiscent of ‘mode locking/unlocking’ physics of tokamak and reversed field pinch experiments. The theory describes transitions between two asymptotic solutions, a state with a large non-rotating island and a state where rotation shielding suppresses island formation. Transitions between these two states are governed by coupled torque balance and island evolution equations. In conventional stellarators, neoclassical damping physics plays an important role in establishing the flow profiles. The balance of neoclassical damping and cross-field viscosity produces a radial boundary layer for the plasma rotation profile outside the separatrix of a locked magnetic island. The width of this boundary layer decreases as the plasma becomes less collisional. This has the consequence of enhancing the viscous torque at low collisionality making healing magnetic islands occur more readily in high temperature conventional stellarators.
Cohen-Kaplansky domains and the Goldbach conjecture
Authors: Coykendall Jim , Spicer Chris
Published: October 2011

A Cohen-Kaplansky domain is an atomic domain with only a finite number of irreducibles. In this paper, we show that localizations of certain orders of rings of integers are necessarily CK-domains, and then prove there exists a closed form formula for the number of irreducible elements in several different cases of these types of rings. Modulo a variant of the Goldbach Conjecture, this construction allows us to answer a question posed by Cohen and Kaplansky over 60 years ago regarding the construction of a CK-domain containing

n
n

nonprime irreducible elements for every positive integer

n
n

.
A coincidence theorem for commuting involutions
Authors: Pergher Pedro
Published: October 2011

Let

M

m

M^{m}

be an

m
m

-dimensional, closed and smooth manifold, and let

S
,
T
:

M

m

→

M

m

S, T:M^{m} \to M^{m}

be two smooth and commuting diffeomorphisms of period

2
2

. Suppose that

S
≠
T

S \not = T

on each component of

M

m

M^{m}

. Denote by

F

S

F_{S}

and

F

T

F_{T}

the respective sets of fixed points. In this paper we prove the following coincidence theorem: if

F

T

F_{T}

is empty and the number of points of

F

S

F_{S}

is of the form

2
p

2p

, with

p
p

odd, then
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper C o i n c left-parenthesis upper S comma upper T right-parenthesis equals StartSet x element-of upper M Superscript m Baseline vertical-bar upper S left-parenthesis x right-parenthesis equals upper T left-parenthesis x right-parenthesis EndSet">

C
o
i
n
c
(
S
,
T
)
=
{
x
∈

M

m

 
|
 
S
(
x
)
=
T
(
x
)
}

Coinc(S,T)=\{x \in M^{m} \ \vert \ S(x)=T(x) \}

has at least some component of dimension

m
−
1

m-1

. This generalizes the classic example given by

M

m

=

S

m

M^{m}=S^{m}

, the

m
m

-dimensional sphere,
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper S left-parenthesis x 0 comma x 1 comma period period period comma x Subscript m Baseline right-parenthesis equals left-parenthesis minus x 0 comma minus x 1 comma period period period comma minus x Subscript m minus 1 Baseline comma x Subscript m Baseline right-parenthesis">

S
(

x

0

,

x

1

,
.
.
.
,

x

m

)
=
(
−

x

0

,
−

x

1

,
.
.
.
,
−

x

m
−
1

,

x

m

)

S(x_{0},x_{1},...,x_{m}) = (-x_{0},-x_{1},...,-x_{m-1},x_{m})

and

T
T

the antipodal map.
SVGMap: configurable image browser for experimental data
Authors: Rafael-Palou Xavier , Schroeder Michael P. , Lopez-Bigas Nuria
Published: October 2011

Summary: Spatial data visualization is very useful to represent biological data and quickly interpret the results. For instance, to show the expression pattern of a gene in different tissues of a fly, an intuitive approach is to draw the fly with the corresponding tissues and color the expression of the gene in each of them. However, the creation of these visual representations may be a burdensome task. Here we present SVGMap, a java application that automatizes the generation of high-quality graphics for singular data items (e.g. genes) and biological conditions. SVGMap contains a browser that allows the user to navigate the different images created and can be used as a web-based results publishing tool.

Availability: SVGMap is freely available as precompiled java package as well as source code at http://bg.upf.edu/svgmap. It requires Java 6 and any recent web browser with JavaScript enabled. The software can be run on Linux, Mac OS X and Windows systems.

Contact:  nuria.lopez@upf.edu
Lipid Resuscitation of Bupivacaine Toxicity
Authors: Li Zhengqian , Xia Yun , Dong Xiaoxi , Chen Hongfei , Xia Fangfang , Wang Xianqin , Dong Huimin , Jin Zhousheng , Ding Xili , Papadimos Thomas J. , Xu Xuzhong
Published: October 2011

Background

The superiority of Intralipid, a long-chain triglyceride (LCT) emulsion versus Lipovenoes, a long- and medium-chain triglyceride (LCT/MCT) emulsion, in reversing local anesthetic-induced cardiac arrest is poorly defined and needs to be determined.

Methods

The study included two parts: in experiment A, bupivacaine (20 mg/kg) was injected to produce asystole. Either Intralipid 20% (LCT group, n = 30) or Lipovenoes 20% (LCT/MCT group, n = 30) with epinephrine was infused immediately. Return of spontaneous circulation and recurrence of asystole after resuscitation were recorded. In experiment B, 80 rats using the same model and resuscitation protocol were divided into 10 groups: LCT₀, LCT₁₅, LCT₃₀, LCT₆₀, and LCT₁₂₀ and LCT/MCT₀, LCT/MCT₁₅, LCT/MCT₃₀, LCT/MCT₆₀, and LCT/MCT₁₂₀ (n = 8 each; the subscripts represent respective observation period). LCT₁₅-LCT₁₂₀ and LCT/MCT₁₅-LCT/MCT₁₂₀ groups received Intralipid 20% or Lipovenoes 20%, respectively. Plasma and myocardial bupivacaine and triglyceride concentrations, as well as myocardial bioenergetics, were determined.

Results

In experiment A, 24 rats in LCT group and 23 in LCT/MCT group achieved return of spontaneous circulation (P = 0.754); among them, 2 (8.3%) and 8 (34.8%) rats suffered a repeated asystole, respectively (P = 0.027). In experiment B, plasma and myocardial bupivacaine concentrations in LCT₁₅ and LCT₆₀ groups were lower than LCT/MCT₁₅ and LCT/MCT₆₀ groups, respectively. Furthermore, the plasma bupivacaine level in LCT/MCT₆₀ group was higher than LCT/MCT₃₀ group (P = 0.003).

Conclusions

LCT emulsion may be superior to LCT/MCT emulsion in treating bupivacaine-related cardiotoxicity as it was associated with fewer recurrences of asystole after resuscitation and lower myocardial bupivacaine concentrations.