bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploring the dynamics of C/H and C/Cl exchanges in the C(3P) + C2H3Cl reaction
Authors: Lee Shih-Huang , Chen Wei-Kan , Chin Chih-Hao , Huang Wen-Jian
Published: October 2013

The dynamics of the C(3P) + C2H3Cl reaction at collision energy 3.8 kcal mol−1 was investigated in a crossed molecular-beam apparatus using synchrotron vacuum-ultraviolet ionization. Time-of-flight spectra of products C3H2Cl, C3H3, and Cl were recorded at various laboratory scattering angles, from which translational-energy distributions and angular distributions of product channels C3H2Cl + H and C3H3 + Cl were derived. Cl correlates satisfactorily with C3H3 in linear momentum and angular distributions, which confirms the production of C3H3 + Cl. The H-loss (Cl-loss) channel has average translational-energy release 14.3 (8.8) kcal mol−1 corresponding to a fraction 0.30 (0.14) of available energy into the translational degrees of freedom of product HCCCHCl + H (H2CCCH + Cl). The branching ratio of channel H to channel Cl was determined approximately as 12:88. The measurements of translational-energy releases and photoionization thresholds cannot distinguish HCCCHCl from H2CCCCl because both isomers have similar enthalpy of formation and ionization energy; nevertheless, the Rice-Ramsperger-Kassel-Marcus calculation prefers HCCCHCl. The measurement of photoionization spectra identifies product C3H3 as H2CCCH (propargyl). Both products C3H2Cl + H and C3H3 + Cl might correlate to the same triplet intermediate H2CCCHCl but have distinct angular distributions; the former is nearly isotropic whereas the latter is forward biased. A comparison with the C(3P) + C2H3F reaction is stated.
Critical role of the sample preparation in experiments using piezoelectric actuators inducing uniaxial or biaxial strains
Authors: Butkovičová D. , Marti X. , Saidl V. , Schmoranzerová-Rozkotová E. , Wadley P. , Holý V. , Němec P.
Published: October 2013

We report on a systematic study of the stress transferred from an electromechanical piezo-stack into GaAs wafers under a wide variety of experimental conditions. We show that the strains in the semiconductor lattice, which were monitored in situ by means of X-ray diffraction, are strongly dependent on both the wafer thickness and on the selection of the glue which is used to bond the wafer to the piezoelectric actuator. We have identified an optimal set of parameters that reproducibly transfers the largest distortions at room temperature. We have studied strains produced not only by the frequently used uniaxial piezostressors but also by the biaxial ones which replicate the routinely performed experiments using substrate-induced strains but with the advantage of a continuously tunable lattice distortion. The time evolution of the strain response and the sample tilting and/or bending are also analyzed and discussed.
Cooling a low noise amplifier with a micromachined cryogenic cooler
Authors: Cao H. S. , Witvers R. H. , Vanapalli S. , Holland H. J. , ter Brake H. J. M.
Published: October 2013

The sensitivity of antenna systems increases with increasing active area, but decreases at higher noise figure of the low-noise amplifier (LNA). Cooling the LNA locally results in significant improvement in the gain and in lowering the noise figure of the LNA. Micromachined Joule-Thomson (JT) coolers can provide a cryogenic environment to the LNA. They are attractive because they have no cold moving parts and can be scaled down to match the size and the power consumption of LNAs. The performance of a LNA mounted on a JT microcooler with dimensions of 60.0 × 9.5 × 0.72 mm3 is reported in this paper. The microcooler is operated with nitrogen gas and the cold-end temperature is controlled at 115 K. The measured net cooling power of the microcooler is about 43 mW when the LNA is not operating. The power dissipation of the LNA is 26 mW, with a supply voltage of 2 V. At room temperature the noise figure of the LNA is 0.83 dB and the gain lies between 17.9 and 13.1 dB, in the frequency range of 0.65 and 1.05 GHz. Upon cooling to 115 K, the noise figure drops to 0.50 dB and the increase in gain varies in the range of 0.6–1.5 dB.
Plasmonic nanoparticles and metasurfaces to realize Fano spectra at ultraviolet wavelengths
Authors: Argyropoulos Christos , Monticone Francesco , D'Aguanno Giuseppe , Alù Andrea
Published: October 2013

We discuss the possibility to realize sharp Fano scattering signatures in the ultraviolet (UV) range, based on dipolar scattering of nanoparticles. At these frequencies, material losses usually do not allow sharp resonant effects, hindering plasmonic applications based on higher-order multipolar modes, like conventional Fano resonances. We propose to excite degenerate scattering states supported by core-shell nanoparticles made of a sapphire core and an aluminum shell. We predict enhanced, highly confined fields, supporting sharp far-field scattering signatures from single nanoparticles and planar arrays of them. These results may lead to the design of UV filters, photodetectors, sensors, and energy-harvesting devices.
Strain-controlled interface engineering of binding and charge doping at metal-graphene contacts
Authors: Gong Wenbin , Zhang Wei , Ren Cuilan , Ke Xuezhi , Wang Song , Huai Ping , Zhang Wenqing , Zhu Zhiyuan
Published: October 2013

Strain effects on tuning the interface binding as well as the charge doping at metal-graphene contacts have been investigated by using density functional theory calculations. A realizable tensile strain is found to be very effective in enhancing the interface binding as well as shifting the Fermi level. Particularly, an enhancement of the binding energy up to 315% can be achieved because of the dipole-dipole interaction. Our results presented here show that strain is an efficient way to overcome the weak binding problem at metal-graphene interface, and will motivate active experimental efforts in improving the performance of graphene-based devices.
Drifting potential humps in ionization zones: The “propeller blades” of high power impulse magnetron sputtering
Authors: Anders André , Panjan Matjaž , Franz Robert , Andersson Joakim , Ni Pavel
Published: October 2013

Ion energy distribution functions measured for high power impulse magnetron sputtering show features, such as a broad peak at several 10 eV with an extended tail, as well as asymmetry with respect to E×B, where E and B are the local electric and magnetic field vectors, respectively. Here it is proposed that those features are due to the formation of a potential hump of several 10 V in each of the traveling ionization zones. Potential hump formation is associated with a negative-positive-negative space charge that naturally forms in ionization zones driven by energetic drifting electrons.
Photoacoustic methods for in vitro study of kinetics progesterone release from the biodegradation of polyhydroxybutyrate/polycaprolactone used as intravaginal devices
Authors: Souza Filho N. E. , Mariucci V. V. G. , Dias G. S. , Szpak W. , Miguez P. H. P. , Madureira E. H. , Medina A. N. , Baesso M. L. , Bento A. C.
Published: October 2013

Intravaginal devices composed of polyhydroxybutyrate/polycaprolactone blends incorporating progesterone were used over eight days in crossbred cow ovariectomized, and then analyzed with photoacoustic methods, measuring the absorption spectra, thermal diffusivity, and inspecting its degradation by means of scanning electron microscopy. The characteristic time found for progesterone release was TR ∼ 53 h, and the typical time found for biodegradation was TB ∼ 30 h. Morphological analysis complements the study showing that release of progesterone and biodegradation of the blend occurs on sample surface.
Characterization of hollow BaTiO3 nanofibers and intense visible photoluminescence
Authors: Woong Lee Kui , Siva Kumar Koppala , Heo Gaeun , Seong Maeng-Je , Yoon Jong-Won
Published: October 2013

BaTiO3 hollow nanofibers were fabricated by electrospinning and then subsequent calcination of as-spun nanofibers with a heating rate of 2.5 °C/min. Scanning electron microscope and transmission electron microscope (TEM) results indicated that the heating rate had a significant effect on the morphology of the BaTiO3 hollow nanofibers. The X-ray diffraction, Raman spectroscopy, and TEM results indicate the prepared BaTiO3 hollow nanofibers have tetragonal phases. From the results of the X-ray photoelectron spectroscopy analysis, in the amorphous BaTiO3 nanofiber, peaks at 457.2 eV for Ti 2p3/2 were also found, which corresponded to the Ti3+ ions. However, in the crystalline BaTiO3 nanofibers, peaks of Ti 2p3/2 showed the Ti4+ ions. Intense visible photoluminescence was observed in the amorphous BaTiO3 nanofiber, which is calcined below a temperature of 500 °C. The observed intense photoluminescence was ascribed to a multiphonon process with localized states within the band gap of the highly disordered states. In the crystalline BaTiO3 hollow fiber, low intensity of photoluminescence showed at the visible region, which is originated from an intrinsic Ba defect.
Takagi-Sugeno fuzzy modeling and chaos control of partial differential systems
Authors: Vasegh Nastaran , Khellat Farhad
Published: October 2013

In this paper a unified approach is presented for controlling chaos in nonlinear partial differential systems by a fuzzy control design. First almost all known chaotic partial differential equation systems are represented by Takagi-Sugeno fuzzy model. For investigating design procedure, Kuramoto-Sivashinsky (K-S) equation is selected. Then, all linear subsystems of K-S equation are transformed to ordinary differential equation (ODE) systems by truncated Fourier series of sine–cosine functions. By solving Riccati equation for each ODE systems, parallel stabilizing feedback controllers are determined. Finally, a distributed fuzzy feedback for K-S equation is designed. Numerical simulations are given to show that the distributed fuzzy controller is very easy to design, efficient, and capable to extend.
Few layer graphene based superlattices as efficient thermal insulators
Authors: Ni Yuxiang , Chalopin Yann , Volz Sebastian
Published: October 2013

While graphene and few layer graphene (FLG) are considered as having the highest thermal conductivity in their in-plane directions, our molecular dynamics (MD) simulations however show that those systems are also characterized by a superior thermal contact resistance, which could be largely tuned with the layer number when in contact with a silica substrate. Taking advantages of such a resistive interface, MD simulations show that SiO2/FLG superlattices have a thermal conductivity as low as 0.30 W/m K, exhibiting a promising prospect in nano-scale thermal insulation. These findings pave the way for an improved thermal management of nanoscale systems such as thermal barrier coatings and phase change memory materials with atomic-scale super-insulators.
Demonstration of bi-directional microwave-assisted magnetic reversal in synthetic ferrimagnets
Authors: Koop B. C. , Dzhezherya Yu. I. , Demishev K. , Yurchuk V. , Worledge D. C. , Korenivski V.
Published: October 2013

We study spin dynamics in synthetic ferrimagnets, in which two dipole-coupled magnetic nanoparticles are different in thickness or biased asymmetrically with an external field. We observe a splitting of the optical spin-resonance for the two antiparallel ground states of the system and demonstrate how this splitting can be used to deterministically select a particular ground state. The demonstrated resonant switching is a fast and low-field way of controlling the magnetic state of nanodevices currently used in such large scale applications as magnetic random access memory.
Possible enhancement of physical properties of nematic liquid crystals by doping of conducting polymer nanofibres
Authors: Manda R. , Dasari V. , Sathyanarayana P. , Rasna M. V. , Paik P. , Dhara Surajit
Published: October 2013

We report on the preparation and physical characterization of the colloidal suspension of conducting polyaniline (PANI) nanofibres and a nematic liquid crystal (5CB). The ac electrical conductivity anisotropy increases significantly and the rotational viscosity decreases with increasing wt. % of PANI nanofibres, while other physical properties such as birefringence, dielectric anisotropy, splay, and bend elastic constants are changed moderately. The high conductivity anisotropy of liquid crystal nano-composites is very useful for magnetically steered liquid crystal-nanofibre switch.
Two-phase versus two-stage versus multi-phase lithiation kinetics in silicon
Authors: Cui Zhiwei , Gao Feng , Qu Jianmin
Published: October 2013

We classify the lithiation process into three types, namely, two-phase, two-stage, and multi-phase lithiation. We found that under a given charging rate, smaller electrochemical Biot number of β will likely to result in two-phase lithiation, while larger β may lead to multi-phase lithiation. For the film anode, intermediate β, or intermediate charging rate, will yield two-stage lithiation, and the Li concentration during the first stage of the lithiation is determined by the relationship between β and the charging rate (or more precisely the Li flux supplied to the Si/LixSi phase interface). Such two-stage lithiation does not occur in the particle or fiber anode.
Aluminum doping induced columnar growth of homoepitaxial ZnO films by metalorganic chemical vapor deposition
Authors: Ding K. , Hu Q. C. , Wang X. , Zhang J. Y. , Lin W. W. , Lin C. S. , Huang F.
Published: October 2013

The effect of aluminum doping on the growth of ZnO films on c-plane ZnO (0001) single crystal substrates during metalorganic chemical vapor deposition was investigated. It was found that aluminum doping induces a growth mode of three-dimensional columnar growth. X-ray photoemission spectroscopy demonstrates that partial aluminum is segregated to the growth front. A combined experimental contact angle measurements and theoretical first-principle calculations suggest that the surface energy of the films is promoted by aluminum doping. Besides, aluminum doping also tends to decrease the adatoms diffusion mobility. We conclude that aluminum acts as an antisurfactant element during the homoepitaxial growth, and it increases the difficulty in obtaining high quality n-type ZnO films.
Border trap characterization in amorphous indium-gallium-zinc oxide thin-film transistors with SiOX and SiNX gate dielectrics
Authors: Jeong Chan-Yong , Lee Daeun , Song Sang-Hun , Cho In-Tak , Lee Jong-Ho , Cho Eou-Sik , Kwon Hyuck-In
Published: October 2013

We investigate the border traps in amorphous indium-gallium-zinc oxide thin-film transistors with SiOX and SiNX interfacial gate dielectrics. Border traps have been known as trapping centers of electronic carriers in field-effect transistors, and non-negligible hysteresis is observed in the bidirectional high-frequency capacitance-voltage curve with a slow ramp rate in both dielectric devices. From the gate voltage transient method and 1/f noise analysis, the spatially and energetically uniform trap distribution is obtained, and approximately four to five times higher border trap densities are extracted from SiNX dielectric devices than from the SiOX dielectric ones.
Antisites and anisotropic diffusion in GaAs and GaSb
Authors: Tahini H. A. , Chroneos A. , Bracht H. , Murphy S. T. , Grimes R. W. , Schwingenschlögl U.
Published: October 2013

The significant diffusion of Ga under Ga-rich conditions in GaAs and GaSb is counter intuitive as the concentration of Ga vacancies should be depressed although Ga vacancies are necessary to interpret the experimental evidence for Ga transport. To reconcile the existence of Ga vacancies under Ga-rich conditions, transformation reactions have been proposed. Here, density functional theory is employed to calculate the formation energies of vacancies on both sublattices and the migration energy barriers to overcome the formation of the vacancy-antisite defect. Transformation reactions enhance the vacancy concentration in both materials and migration energy barriers indicate that Ga vacancies will dominate.
Triple-band high-temperature superconducting microstrip filter based on multimode split ring resonator
Authors: Liu Hai-Wen , Wang Yan , Fan Yi-Chao , Guan Xue-Hui , He Yusheng
Published: October 2013

A compact triple-band high-temperature superconducting (HTS) YBa2Cu3Oy microstrip bandpass filter using multimode split ring resonator (SRR) is presented in this letter. Also, its properties and equivalent circuit models are investigated by even- and odd-mode analysis. Moreover, design method of the proposed triple-band HTS filter for the applications of global positioning system at 1.57 GHz, worldwide interoperability for microwave access at 3.5 GHz, and wireless local area networks at 5.8 GHz is discussed. The centre frequencies and the bandwidths of the three passbands can be allocated properly choosing the dimension parameters of the multimode SRR. In addition, four transmission zeros are produced to improve the selectivity of this filter.
High-efficiency fabrication of aspheric microlens arrays by holographic femtosecond laser-induced photopolymerization
Authors: Hu Yanlei , Chen Yuhang , Ma Jianqiang , Li Jiawen , Huang Wenhao , Chu Jiaru
Published: October 2013

Manufacture of aspheric microlens has always been technically challenging for conventional approaches due to their complex curved profile and tiny sizes. Two-photon polymerization is capable of producing arbitrary shape with high spatial resolution, apart from the disadvantage of ultra-low rate of yield resulting from point-by-point writing strategy. Here, we report parallel fabrication of aspheric microlens arrays (AMLAs) by taking advantage of holographic femtosecond laser direct-writing. The inherent constraints of the spatial light modulator are taken into consideration for achieving improved intensity uniformity and enhanced diffraction efficiency. Closely-packed AMLAs with designable optical parameters are readily fabricated with excellent optical performance.
Analysis of remote synchronization in complex networks
Authors: Gambuzza Lucia Valentina , Cardillo Alessio , Fiasconaro Alessandro , Fortuna Luigi , Gómez-Gardeñes Jesus , Frasca Mattia
Published: October 2013

A novel regime of synchronization, called remote synchronization, where the peripheral nodes form a phase synchronized cluster not including the hub, was recently observed in star motifs [Bergner et al., Phys. Rev. E 85, 026208 (2012)]. We show the existence of a more general dynamical state of remote synchronization in arbitrary networks of coupled oscillators. This state is characterized by the synchronization of pairs of nodes that are not directly connected via a physical link or any sequence of synchronized nodes. This phenomenon is almost negligible in networks of phase oscillators as its underlying mechanism is the modulation of the amplitude of those intermediary nodes between the remotely synchronized units. Our findings thus show the ubiquity and robustness of these states and bridge the gap from their recent observation in simple toy graphs to complex networks.
Increasing the efficiency of the passive loading strategy for wave energy conversion
Authors: de la Villa Jaén Antonio , Andrade Dan El Montoya , García Santana Agustín
Published: October 2013

The control strategy applied to the oscillating system of the wave energy converters largely determines the overall system efficiency and thus the energy production. One of the first proposed control strategies for this type of device is the passive control. This type of control continues currently to be considered because it can be implemented in a simple way: short-term predictions about the performance of the wave are not needed when passive control is applied. Moreover, the power flow is unidirectional, and the extraction system is subjected to moderate peak powers so that costs and dimensions of the wave energy converter components can be reduced. The main disadvantage of passive loading control is the low energy production compared with other control strategies, such as the so-called reactive control which requires bidirectional power flow between the oscillating system and the generator. This way, the device can extract more energy from the waves, but the global system requires large energy exchanges between the oscillating device and the generator. These energy exchanges cause high losses, and thus the overall system efficiency significantly decreases. Furthermore, the reactive control system involves high oscillating excursions that can become unacceptable. In this paper, a point absorber converter that uses a linear direct-drive generator and power electronics converters jointly is considered. This article presents a passive control strategy that optimizes the power transferred from the generator to the power electronic converter considering the copper losses in the electric generator. Applying this approach, the generation system efficiency increases significantly, and similar values of the oscillating system's heave excursions and the peak-to-average power ratio for both the conventional and the proposed passive loading are found. The formulation of the proposed method is presented as well as time domain wave-to-wire simulations in both regular and irregular waves.
Distribution state estimation with renewable sources based distributed generations using a modified quantum-inspired evolutionary algorithm
Authors: Zhao J. B. , Zhang G. X. , Wang X. R. , Zou D. H.
Published: October 2013

Distribution state estimation (DSE) is becoming more and more important in distribution control center considering deregulation and introduction of renewable sources based distributed generations (REDGs). To realize the real-time estimation of the load and REDGs output values with limited monitoring devices in a distribution network, this paper presents a novel DSE approach by introducing a Modified Quantum-Inspired Evolutionary Algorithm (mQIEA) combining a QIEA with Greedy Randomized Adaptive Search Procedures (GRASP). Thirteen knapsack problems, which are well-known as NP-hard ones, with various items are used to compare mQIEA with four QIEA variants. IEEE34 and IEEE70 test systems with REDGs are applied to conduct DSE experiments. Results show that mQIEA outperforms four QIEA variants in terms of the solution quality and that mQIEA obtains better estimation results than eight optimization algorithms reported in the recent literature with respect to the maximally relative error, maximally absolute error, and estimation precision.
Advancing image quantification methods and tools for analysis of nanoparticle electrokinetics
Authors: Bakewell D. J. , Bailey J. , Holmes D.
Published: October 2013

Image processing methods and techniques for high-throughput quantification of dielectrophoretic (DEP) collections onto planar castellated electrode arrays are developed and evaluated. Fluorescence-based dielectrophoretic spectroscopy is an important tool for laboratory investigations of AC electrokinetic properties of nanoparticles. This paper details new, first principle, theoretical and experimental developments of geometric feature recognition techniques that enable quantification of positive dielectrophoretic (pDEP) nanoparticle collections onto castellated arrays. As an alternative to the geometric-based method, novel statistical methods that do not require any information about array features, are also developed using the quantile and standard deviation functions. Data from pDEP collection and release experiments using 200 nm diameter latex nanospheres demonstrates that pDEP quantification using the statistic-based methods yields quantitatively similar results to the geometric-based method. The development of geometric- and statistic-based quantification methods enables high-throughput, supervisor-free image processing tools critical for dielectrophoretic spectroscopy and automated DEP technology development.
Modelling the growth of ZnO nanocombs based on the piezoelectric effect
Authors: Fattahi Comjani F. , Willer U. , Kontermann S. , Schade W.
Published: October 2013

In this work a model for the growth of ZnO nanocombs based on the piezoelectric character of ZnO is presented that explains the periodic growth of nanowire branches on the polar +(0001) surface of a ZnO nanobelt as a self catalytic growth process. In this model the perturbation and elasticity theory are applied to approximate the induced mechanical strain and piezoelectric potential distribution in the nanobelt under the growth kinetics. To implement a quantitative simulation of the periodic growth of ZnO nanobranches the induced piezoelectric charges in the ZnO nanostructure are calculated. These are responsible for the structural transformation from a nanobelt into a nanocomb. A comparison with nanocombs that are synthesized using the vapor-liquid-solid method shows good agreement between experimental and theoretical results.
Variation in leaf morphology of the invasive cat's claw creeper Dolichandra unguis-cati (Bignoniaceae)
Authors: Boyne Richard L. , Harvey Susan P. , Dhileepan Kunjithapatham , Scharaschkin Tanya
Published: October 2013

The invasive liana cat’s claw creeper Dolichandra unguis-cati (L.) L.G. Lohmann (syn. Macfadyena unguis-cati (L.) A.H. Gentry) exhibits intraspecific variation in leaf morphology, but this is rarely noted in the published literature. The present study documents variation in leaf morphology in two forms of the species that occur in Australia (long pod and short pod). Leaf morphology is compared between the two forms and the position of the shoots (trunk and ground) at the only two sites in which they co-occur. Leaves were categorised on the basis of leaflet number and the presence or absence of tendrils. Simple leaves were produced mainly on shoots growing along the ground and were more abundant in the short-pod form. Long-pod plants were dominated by bifoliate leaves with tendrils. Cat’s claw creeper exhibits considerably wider variation in leaf morphology than recorded previously. Variations in leaf morphology may be linked to differences in the genotype, developmental stage and plastic responses of the plants. Understanding these variations may have implications for taxonomic delimitation and improved management, particularly biological control involving leaf-feeding insects.
Arf6 coordinates actin assembly through the WAVE complex, a mechanism usurped by
Salmonella
to invade host cells
Authors: Humphreys Daniel , Davidson Anthony C. , Hume Peter J. , Makin Laura E. , Koronakis Vassilis
Published: October 2013

Significance

The small GTPase ADP ribosylation factor (Arf) 6 anchors to the plasma membrane, where it coordinates actin filament polymerization to remodel the membrane-associated cytoskeleton in diverse cell processes, yet how Arf6 directs actin polymerization is unknown. By reconstituting membrane-associated actin assembly, we find that Arf6 assembles actin via the WAVE regulatory complex (WRC). In contrast to other Arf family members, which directly bind and activate WRC, Arf6 signaled to WRC indirectly by recruiting the Arf1 activator ARNO to the membrane. Remarkably, we demonstrate this mechanism is hijacked by the pathogen
Salmonella
that usurped Arf6 and WRC to invade human host cells and establish intracellular infection. This study describes a mechanism for Arf6-driven actin polymerization.
Prostaglandin E2deficiency causes a phenotype of aspirin sensitivity that depends on platelets and cysteinyl leukotrienes
Authors: Liu Tao , Laidlaw Tanya M. , Katz Howard R. , Boyce Joshua A.
Published: October 2013

Significance

Aspirin-exacerbated respiratory disease (AERD) is a common, severe variant of asthma, which is associated with overproduction of cysteinyl leukotrienes (cysLTs) and respiratory reactions to drugs that block cyclooxygenase 1. We demonstrate that mice selectively lacking the capacity to up-regulate the generation of prostaglandin E2with inflammation develop an AERD-like phenotype that depends critically on platelets and thromboxane receptors, which drive transcellular synthesis of cysLTs, which, in turn, activate mast cells with aspirin challenge. The findings suggest a role for antiplatelet or thromboxane-selective antagonists as treatments for AERD.
Intermediate closed state for glycine receptor function revealed by cysteine cross-linking
Authors: Prevost Marie S. , Moraga-Cid Gustavo , Van Renterghem Catherine , Edelstein Stuart J. , Changeux Jean-Pierre , Corringer Pierre-Jean
Published: October 2013

Significance

Glycine receptors are ligand-gated ion channels involved in inhibitory synaptic communication. These membrane proteins undergo conformational transitions between resting, active (with an open channel), and desensitized (closed) states. For the present paper, we chemically cross-linked two regions in the upper part of the ion channel. We show by electrophysiological methods that it results in the stabilization of a new closed state. This new state likely corresponds to an “intermediate conformation” occurring during activation or desensitization, yielding insights into the molecular mechanism of signal transduction.
New properties of multiple harmonic sums modulo 𝑝 and 𝑝-analogues of Leshchiner’s series
Authors: Pilehrood Kh. , Pilehrood T. , Tauraso R.
Published: October 2013

In this paper we present some new binomial identities for multiple harmonic sums whose indices are the sequences

(
{
1

}
a

,
c
,
{
1

}
b

)
,

(\{1\}^a,c,\{1\}^b),

(
{
2

}
a

,
c
,
{
2

}
b

)

(\{2\}^a,c,\{2\}^b)

and prove a number of congruences for these sums modulo a prime

p
.

p.

The congruences obtained allow us to find nice

p
p

-analogues of Leshchiner’s series for zeta values and to refine a result due to M. Hoffman and J. Zhao about the set of generators of the multiple harmonic sums of weight

7
7

and

9
9

modulo

p
p

. As a further application we provide a new proof of Zagier’s formula for

ζ

∗

(
{
2

}
a

,
3
,
{
2

}
b

)

\zeta ^{*}(\{2\}^a,3,\{2\}^b)

based on a finite identity for partial sums of the zeta-star series.
Mammal disparity decreases during the Cretaceous angiosperm radiation
Authors: Grossnickle David M. , Polly P. David
Published: October 2013

Fossil discoveries over the past 30 years have radically transformed traditional views of Mesozoic mammal evolution. In addition, recent research provides a more detailed account of the Cretaceous diversification of flowering plants. Here, we examine patterns of morphological disparity and functional morphology associated with diet in early mammals. Two analyses were performed: (i) an examination of diversity based on functional dental type rather than higher-level taxonomy, and (ii) a morphometric analysis of jaws, which made use of modern analogues, to assess changes in mammalian morphological and dietary disparity. Results demonstrate a decline in diversity of molar types during the mid-Cretaceous as abundances of triconodonts, symmetrodonts, docodonts and eupantotherians diminished. Multituberculates experience a turnover in functional molar types during the mid-Cretaceous and a shift towards plant-dominated diets during the late Late Cretaceous. Although therians undergo a taxonomic expansion coinciding with the angiosperm radiation, they display small body sizes and a low level of morphological disparity, suggesting an evolutionary shift favouring small insectivores. It is concluded that during the mid-Cretaceous, the period of rapid angiosperm radiation, mammals experienced both a decrease in morphological disparity and a functional shift in dietary morphology that were probably related to changing ecosystems.
Emergence of carbapenem-resistant Acinetobacter baumannii in hospitals in Pakistan
Authors: Hasan Badrul , Perveen Khalida , Olsen Björn , Zahra Rabaab
Published: October 2013

The emergence of pan-resistance in bacterial pathogens poses a threat to human health. Carbapenem-resistant Acinetobacter baumannii has emerged as a serious challenge, causing nosocomial infection and community-acquired outbreaks in hospitals globally, including in Pakistan. We collected 90 Acinetobacter isolates from patients with secondary or nosocomial infections from different hospitals in Pakistan and screened for carbapenem-resistant strains. Of the 90 isolates, 59 were resistant to carbapenems. Among oxacillinase -encoding genes, bla
OXA-51-like was common in all isolates, including in combination with bla
OXA-23-like in 14 isolates; however, bla
OXA-24-like and bla
OXA-58-like were completely absent. Among metallo-β-lactamase-encoding genes, only bla
NDM-1 was found in one isolate, while the other three genes, bla
IMP, bla
VIM and bla
SIM, were completely absent. None of the isolates was found to harbour the bla
CTX-M gene. The isolates were also tested for susceptibilities to a panel of different antibiotics belonging to several classes. Of all the drugs tested, tigecycline was the most effective with 80 % sensitivity amongst isolates, followed by colistin with 50 % sensitivity. Three categories of resistance were found in these isolates: extreme drug resistance in 26, pan-drug resistance in 19 and multidrug resistance in 87 isolates. The isolates exhibited a high resistance to cephalosporins, trimethoprim–sulfamethoxazole and β-lactam antibiotics, followed by tetracycline and β-lactam/β-lactam inhibitor combination, fluoroquinolone and aminoglycosides. The results show a prominent level of antibiotic-resistance phenotypes in A. baumannii and strongly suggest the need for full-scale national surveillance of carbapenem-resistant A. baumannii with particular emphasis on the newly identified NDM-1 (New Delhi metallo-β-lactamase-1).
The Geobacillus paradox: why is a thermophilic bacterial genus so prevalent on a mesophilic planet?
Authors: Zeigler Daniel R.
Published: October 2013

The genusGeobacilluscomprises endospore-forming obligate thermophiles. These bacteria have been isolated from cool soils and even cold ocean sediments in anomalously high numbers, given that the ambient temperatures are significantly below their minimum requirement for growth. Geobacilli are active in environments such as hot plant composts, however, and examination of their genome sequences reveals that they are endowed with a battery of sensors, transporters and enzymes dedicated to hydrolysing plant polysaccharides. Although they appear to be relatively minor members of the plant biomass-degrading microbial community,Geobacillusbacteria have achieved a significant population with a worldwide distribution, probably in large part due to adaptive features of their spores. First, their morphology and resistance properties enable them to be mobilized in the atmosphere and transported long distances. Second, their longevity, which in theory may be extreme, enables them to lie quiescent but viable for long periods of time, accumulating gradually over time to achieve surprisingly high population densities.
Chlorhexidine solutions in histological and histochemical techniques1
Authors: Heyden Guy , Arwill Tore , Liua Jan , Magnusson Bengt C.
Published: October 2013

Abstract. Chlorhexidine solutions have been tested to determine their usefulness as media for the transport of biopsy specimens for diagnosis in order to facilitate the use of cold microtome sectioning and enzyme histochemical techniques in routine histopathological diagnostic practice. The drug was chosen for its antibacterial and protein “preserving” capacities. Tissue morphology, chemical components and enzyme activities were found to be retained well in specimens from human gingiva when stored in a cold solution, pH 7.2, containing 2.2 mM chlorhexidine gluconate, 0.19 M cacodylate buffer and 7.5% polyvinylpyrrolidone. The procedure allowed reliable enzyme activity evaluations to be performed under the light microscope within 48 hours after excision of the tissues. Fresh frozen tissues served as controls. In an additional electron microscopic study, morphology of the cells was found to be reasonably well preserved after transport in the solution.
Role of smoking in floor of the mouth leukoplakias
Authors: Pindborg J. J. , Roed‐Petersen B. , Renstrup G.
Published: October 2013

Abstract. On the basis of 48 patients wilh leukoplakia on the floor of the mouth, the study has shown that (1) of thc patients with leukoplakias i n this location, two‐thirds are female, as opposed to a ratio of onc‐third females for other locntions, (2) the habit of cheroot smoking is often associated with the floor of the mouth Icukoplnkia, (3) 6% of the 36 biopsics exhibited epithelial atypia, and (4) the floor of the mouth leukoplakias should not be coiisidcred epithelial nevi.
Development of Research in Experimental Design in India
Authors: Dey Aloke , Mukerjee Rahul
Published: October 2013

Cet article présente un panorama de la recherche indienne des 70 dernières années dans le domaine des plans d’expériences. Le travail accompli dans ce cadre est considérable, tant par le volume que par l'importance des contributions, et nous nous sommes attachés à en présenter un historique cohérent. Les sujets traités incluent les carrés latins mutuellement orthogonaux, les plans en blocs incomplets, les plans factoriels, les plans factoriels fractionnaires, les surfaces de réponse, les plans mixtes, les plans ligne‐colonne et les études croisées.
Discussion: Statistics Research in Business and Industry ‐ The General Electric Experience
Authors: Hahn Gerald J. , Hoerl Roger , Doganaksoy Necip , Gardner Martha
Published: October 2013

For over 60 years, the statistics group at General Electric (GE) has used statistical methods to successfully address key company issues, both reactively and in recent years more and more proactively and holistically. Much of this work invariably calls for some degree of statistics research, including what we now call statistical engineering. We briefly review the history of research at GE, describe the accomplishments, research, and evolution of the GE statistics group over time, and present our views on the state of statistics research in business and industry.
Applications of the Likelihood Theory in Finance: Modelling and Pricing
Authors: Janssen Arnold , Tietje Martin
Published: October 2013

This paper discusses the connection between mathematical finance and statistical modelling which turns out to be more than a formal mathematical correspondence. We like to figure out how common results and notions in statistics and their meaning can be translated to the world of mathematical finance and vice versa. A lot of similarities can be expressed in terms of LeCam’s theory for statistical experiments which is the theory of the behaviour of likelihood processes. For positive prices the arbitrage free financial assets fit into statistical experiments. It is shown that they are given by filtered likelihood ratio processes. From the statistical point of view, martingale measures, completeness, and pricing formulas are revisited. The pricing formulas for various options are connected with the power functions of tests. For instance the Black–Scholes price of a European option is related to Neyman–Pearson tests and it has an interpretation as Bayes risk. Under contiguity the convergence of financial experiments and option prices are obtained. In particular, the approximation of Itô type price processes by discrete models and the convergence of associated option prices is studied. The result relies on the central limit theorem for statistical experiments, which is well known in statistics in connection with local asymptotic normal (LAN) families. As application certain continuous time option prices can be approximated by related discrete time pricing formulas.
Aldosterone Escape With Diuretic or Angiotensin‐Converting Enzyme Inhibitor/Angiotensin II Receptor Blocker Combination Therapy in Patients With Mild to Moderate Hypertension
Authors: Ubaid‐Girioli Samira , Ferreira‐Melo Sílvia Elaine , Souza Leoní Adriana , Nogueira Eduardo Arantes , Yugar‐Toledo Juan Carlos , Coca Antonio , Moreno Heitor
Published: October 2013

Renin‐angiotensin‐aldosterone system (RAAS) hyperactivity is implicated in the development of hypertension and progressive damage in target organs. Chronic inhibition of the RAAS or use of thiazide‐type diuretics may trigger an aldosterone escape. The aim of this study was to assess this phenomenon in hypertensive patients treated with thiazide‐type diuretics (hydrochlorothiazide [HCTZ]) or single or double blockade of the RAAS (irbesartan [IRBE], quinapril [QUIN], and IRBE+QUIN). Blood pressure levels were obtained by 24‐hour ambulatory blood pressure monitoring. Plasma renin activity and aldosterone levels were determined by immunoradiometric assay. Blood pressure level was normalized in the 4 treatment groups; the HCTZ and IRBE+QUIN groups showed an increased plasma aldosterone level after 12 weeks (9.1 ±2.2 to 14.1 ±1.4 and 6.9±1.9 to 12.9±2.3 ng/dL, respectively; P<.05), whereas plasma renin activity was increased only in the HCTZ group (0.9 ±0.2‐1.7 ±0.2 ng/mL/h; P<.05). The increase in plasma aldosterone level after 12 weeks of HCTZ and IRBE+QUIN therapy suggests early aldosterone escape.
Space and phase resolved ion energy and angular distributions in single- and dual-frequency capacitively coupled plasmas
Authors: Zhang Yiting , Kushner Mark J. , Moore Nathaniel , Pribyl Patrick , Gekelman Walter
Published: October 2013

The control of ion energy and angular distributions (IEADs) is critically important for anisotropic etching or deposition in microelectronic fabrication processes. With single frequency capacitively coupled plasmas (CCPs), the narrowing in angle and spread in energy of ions as they cross the sheath are definable functions of frequency, sheath width, and mean free path. With increases in wafer size, single frequency CCPs are finding difficulty in meeting the requirement of simultaneously controlling plasma densities, ion fluxes, and ion energies. Dual-frequency CCPs are being investigated to provide this flexible control. The high frequency (HF) is intended to control the plasma density and ion fluxes, while the ion energies are intended to be controlled by the low frequency (LF). However, recent research has shown that the LF can also influence the magnitude of ion fluxes and that IEADs are determined by both frequencies. Hence, separate control of fluxes and IEADs is complex. In this paper, results from a two-dimensional computational investigation of Ar/O2 plasma properties in an industrial reactor are discussed. The IEADs are tracked as a function of height above the substrate and phase within the rf cycles from the bulk plasma to the presheath and through the sheath with the goal of providing insights to this complexity. Comparison is made to laser-induced fluorescence experiments. The authors found that the ratios of HF/LF voltage and driving frequency are critical parameters in determining the shape of the IEADs, both during the transit of the ion through the sheath and when ions are incident onto the substrate. To the degree that contributions from the HF can modify plasma density, sheath potential, and sheath thickness, this may provide additional control for the IEADs.
Sulfate Metabolites Provide an Intracellular Pool for Resveratrol Generation and Induce Autophagy with Senescence
Authors: Patel Ketan R. , Andreadi Catherine , Britton Robert G. , Horner-Glister Emma , Karmokar Ankur , Sale Stewart , Brown Victoria A. , Brenner Dean E. , Singh Rajinder , Steward William P. , Gescher Andreas J. , Brown Karen
Published: October 2013

Biologically active concentrations of resveratrol can be generated intracellularly after uptake of the major human sulfate metabolites by selected cells.
Peripheral Blood Mononuclear Cell Gene Expression Profiles Predict Poor Outcome in Idiopathic Pulmonary Fibrosis
Authors: Herazo-Maya Jose D. , Noth Imre , Duncan Steven R. , Kim SungHwan , Ma Shwu-Fan , Tseng George C. , Feingold Eleanor , Juan-Guardela Brenda M. , Richards Thomas J. , Lussier Yves , Huang Yong , Vij Rekha , Lindell Kathleen O. , Xue Jianmin , Gibson Kevin F. , Shapiro Steven D. , Garcia Joe G. N. , Kaminski Naftali
Published: October 2013

Genome-scale transcriptomic profiling of peripheral blood mononuclear cells from patients with idiopathic pulmonary fibrosis reveals that decreased expression ofCD28,ICOS,LCK, andITKpredicts mortality.
Length Matters
Authors: Schaefer Anne
Published: October 2013

Reduced transcription of very long genes depends on the activity of topoisomerase enzymes that have been implicated in autism spectrum disorders.
The Two Functional Enoyl-Acyl Carrier Protein Reductases of Enterococcus faecalis Do Not Mediate Triclosan Resistance
Authors: Zhu Lei , Bi Hongkai , Ma Jincheng , Hu Zhe , Zhang Wenbin , Cronan John E. , Wang Haihong
Published: October 2013

Enoyl-acyl carrier protein (enoyl-ACP) reductase catalyzes the last step of the elongation cycle in the synthesis of bacterial fatty acids. The
Enterococcus faecalis
genome contains two genes annotated as enoyl-ACP reductases, a FabI-type enoyl-ACP reductase and a FabK-type enoyl-ACP reductase. We report that expression of either of the two proteins restores growth of an
Escherichia coli
fabI
temperature-sensitive mutant strain under nonpermissive conditions.
In vitro
assays demonstrated that both proteins support fatty acid synthesis and are active with substrates of all fatty acid chain lengths. Although expression of
E. faecalis fabK
confers to
E. coli
high levels of resistance to the antimicrobial triclosan, deletion of
fabK
from the
E. faecalis
genome showed that FabK does not play a detectable role in the inherent triclosan resistance of
E. faecalis
. Indeed, FabK seems to play only a minor role in modulating fatty acid composition. Strains carrying a deletion of
fabK
grow normally without fatty acid supplementation, whereas
fabI
deletion mutants make only traces of fatty acids and are unsaturated fatty acid auxotrophs.

IMPORTANCE
The finding that exogenous fatty acids support growth of
E. faecalis
strains defective in fatty acid synthesis indicates that inhibitors of fatty acid synthesis are ineffective in countering
E. faecalis
infections because host serum fatty acids support growth of the bacterium.
Clinical staff perceptions of palliative care-related quality of care, service access, education and training needs and delivery confidence in an acute hospital setting
Authors: Frey Rosemary , Gott Merryn , Raphael Deborah , O'Callaghan Anne , Robinson Jackie , Boyd Michal , Laking George , Manson Leigh , Snow Barry
Published: October 2013

Context

Central to appropriate palliative care management in hospital settings is ensuring an adequately trained workforce. In order to achieve optimum palliative care delivery, it is first necessary to create a baseline understanding of the level of palliative care education and support needs among all clinical staff (not just palliative care specialists) within the acute hospital setting.

Objectives

The objectives of the study were to explore clinical staff: perceptions concerning the quality of palliative care delivery and support service accessibility, previous experience and education in palliative care delivery, perceptions of their own need for formal palliative care education, confidence in palliative care delivery and the impact of formal palliative care training on perceived confidence.

Methods

A purposive sample of clinical staff members (598) in a 710-bed hospital were surveyed regarding their experiences of palliative care delivery and their education needs.

Results

On average, the clinical staff rated the quality of care provided to people who die in the hospital as ‘good’ (x̄=4.17, SD=0.91). Respondents also reported that 19.3% of their time was spent caring for end-of-life patients. However, only 19% of the 598 respondents reported having received formal palliative care training. In contrast, 73.7% answered that they would like formal training. Perceived confidence in palliative care delivery was significantly greater for those clinical staff with formal palliative care training.

Conclusions

Formal training in palliative care increases clinical staff perceptions of confidence, which evidence suggests impacts on the quality of palliative care provided to patients. The results of the study should be used to shape the design and delivery of palliative care education programmes within the acute hospital setting to successfully meet the needs of all clinical staff.