bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of O-Co-O layer thickness on the thermal conductivity of NaxCo2O4 studied by positron annihilation
Authors: Li H. Q. , Zhao B. , Zhang T. , Li X. F. , He H. F. , Chen Z. Q. , Su X. L. , Tang X. F.
Published: July 2015

Nominal stoichiometric NaxCo2O4 (x = 1.0, 1.2, 1.4, 1.6, 1.8, and 2.0) polycrystals were synthesized by a solid-state reaction method. They were further pressed into pellets by the spark plasma sintering. The crystal structure and morphology of NaxCo2O4 samples were characterized by X-ray diffraction and scanning electron microscopy measurements. Good crystallinity and layered structures were observed for all the samples. Positron annihilation measurements were performed for NaxCo2O4 as a function of Na content. Two lifetime components are resolved. τ1 is attributed mainly to positron annihilation in the O-Co-O layers and shifts to Na layers only in the H3 phase. The second lifetime τ2 is due to positron annihilation in vacancy clusters which may exist in the Na layers or grain boundary region. The size of vacancy clusters grow larger but their concentration decreases with increasing Na content in the range of 1.0 < x < 1.8. The thickness of O-Co-O layer also shows continuous increase with increasing Na content, which is reflected by the increase of τ1. The thermal conductivity κ, on the other hand, shows systematic decrease with increasing Na content. This suggests that the increasing spacing of O-Co-O layer could effectively reduce the thermal conductivity of NaxCo2O4.
Normalization of synthetically generated weather data (synthetic metrological year) of typical climatic zones of Saudi Arabia
Authors: Almofeez Ibraheem A.
Published: July 2015

Energy simulation and modeling in buildings require annual hourly weather data. The accuracy and completeness of the data are vital to assess annual energy performance of building and to evaluate alternative building design strategies. Weather stations in Saudi Arabia conduct and archive weather data measurements for major cities and Airbases. However, these data are summaries or incomplete and in varying formats. In the first part of the present work, weather data were synthetically generated (Synthetic Metrological Year) by using METEONORM 7.0 (MN7), for the cities such as Riyadh, Jeddah, Dhahran, Tabuk, and Khamis, which represent Central, Upland, Northern, Western, and Eastern regions of Saudi Arabia. The weather parameters measured were dry bulb temperature (Ta), global solar radiation (Gh), relative humidity, and wind speed. The MN7 data were compared with the corresponding national Presidency of Meteorology and Environment (PME) data, and observed that in many cases the MN7 data needed proper scrutiny and rectification in order to maintain conformity with the actual data. Therefore, a Microsoft Excel-based normalization procedure was applied to make the MN7 data consistent with the corresponding PME data. It was found that the proposed normalization technique could rectify all the discrepancies of MN7 data and bring them excellently close to the PME data.
Fluid simulation of relativistic electron beam driven wakefield in a cold plasma
Authors: Bera Ratan Kumar , Sengupta Sudip , Das Amita
Published: July 2015

Excitation of wakefield in a cold homogeneous plasma, driven by an ultra-relativistic electron beam is studied in one dimension using fluid simulation techniques. For a homogeneous rigid beam having density (nb) less than or equal to half the plasma density (n0), simulation results are found to be in good agreement with the analytical work of Rosenzweig [Phys. Rev. Lett. 58, 555 (1987)]. Here, Rosenzweig's work has been analytically extended to regimes where the ratio of beam density to plasma density is greater than half and results have been verified using simulation. Further in contrast to Rosenzweig's work, if the beam is allowed to evolve in a self-consistent manner, several interesting features are observed in simulation viz. splitting of the beam into beam-lets (for lb > λp) and compression of the beam (for lb < λp), lb and λp, respectively, being the initial beam length and plasma wavelength.
Enhancement of proton acceleration by frequency-chirped laser pulse in radiation pressure mechanism
Authors: Vosoughian H. , Riazi Z. , Afarideh H. , Yazdani E.
Published: July 2015

The transition from hole-boring to light-sail regime of radiation pressure acceleration by frequency-chirped laser pulses is studied using particle-in-cell simulation. The penetration depth of laser into the plasma with ramped density profile increases when a negatively chirped laser pulse is applied. Because of this induced transparency, the laser reflection layer moves deeper into the target and the hole-boring stage would smoothly transit into the light-sail stage. An optimum chirp parameter which satisfies the laser transparency condition, a0≈πnel/ncλ, is obtained for each ramp scale length. Moreover, the efficiency of conversion of laser energy into the kinetic energy of particles is maximized at the obtained optimum condition. A relatively narrow proton energy spectrum with peak enhancement by a factor of 2 is achieved using a negatively chirped pulse compared with the un-chirped pulse.
Self-consistent evolution of plasma discharge and electromagnetic fields in a microwave pulse compressor
Authors: Shlapakovski A. S. , Beilin L. , Hadas Y. , Schamiloglu E. , Krasik Ya. E.
Published: July 2015

Nanosecond-scale evolution of plasma and RF electromagnetic fields during the release of energy from a microwave pulse compressor with a plasma interference switch was investigated numerically using the code MAGIC. The plasma was simulated in the scope of the gas conductivity model in MAGIC. The compressor embodied an S-band cavity and H-plane waveguide tee with a shorted side arm filled with pressurized gas. In a simplified approach, the gas discharge was initiated by setting an external ionization rate in a layer crossing the side arm waveguide in the location of the electric field antinode. It was found that with increasing ionization rate, the microwave energy absorbed by the plasma in the first few nanoseconds increases, but the absorption for the whole duration of energy release, on the contrary, decreases. In a hybrid approach modeling laser ignition of the discharge, seed electrons were set around the electric field antinode. In this case, the plasma extends along the field forming a filament and the plasma density increases up to the level at which the electric field within the plasma decreases due to the skin effect. Then, the avalanche rate decreases but the density still rises until the microwave energy release begins and the electric field becomes insufficient to support the avalanche process. The extraction of the microwave pulse limits its own power by terminating the rise of the plasma density and filament length. For efficient extraction, a sufficiently long filament of dense plasma must have sufficient time to be formed.
Plasma density diagnostic for capillary-discharge based plasma channels
Authors: Daniels J. , van Tilborg J. , Gonsalves A. J. , Schroeder C. B. , Benedetti C. , Esarey E. , Leemans W. P.
Published: July 2015

The plasma density in discharged laser guiding structures, of order 1018 cm−3, is critical to laser-plasma accelerators. Here, we demonstrate a technique that uses spectral interferometry to measure the on-axis laser group velocity (and thus density) in cm-scale cylindrical hydrogen-discharge plasma channels by using laser pulses with a Gaussian transverse profile. Experimental density retrieval over a range of capillary parameters (density, length, and diameter) is presented. The accuracy (of order 8×1016 cm−3) and shot-to-shot stability (of order 2×1016 cm−3) of the diagnostic are discussed.
Single molecular transistor as a superior gas sensor
Authors: Ray S. J.
Published: July 2015

Single Molecular Transistor (SMT) is known for its quantised nature of transport which can be used for sensing purposes. In this work, a SMT device prototype has been proposed for chemical sensing application, which is sensitive at the single molecular level. The operational methodology and performance have been investigated using first-principles calculations within a density functional theory framework. The charge stability diagram carries unique signature of the molecule present within the SMT and this property can be used to detect the presence of an individual molecule from a mixture of different molecules. Details about the possible experimental realisation of such a device has been discussed. The present approach provides a unique combination of very simple design with operation, perfect gate-island coupling, large temperature range of operation and extremely high detection sensitivity.
Continuum model of tensile fracture of metal melts and its application to a problem of high-current electron irradiation of metals
Authors: Mayer Alexander E. , Mayer Polina N.
Published: July 2015

A continuum model of the metal melt fracture is formulated on the basis of the continuum mechanics and theory of metastable liquid. A character of temperature and strain rate dependences of the tensile strength that is predicted by the continuum model is verified, and parameters of the model are fitted with the use of the results of the molecular dynamics simulations for ultra-high strain rates (≥1–10/ns). A comparison with experimental data from literature is also presented for Al and Ni melts. Using the continuum model, the dynamic tensile strength of initially uniform melts of Al, Cu, Ni, Fe, Ti, and Pb within a wide range of strain rates (from 1–10/ms to 100/ns) and temperatures (from melting temperature up to 70–80% of critical temperature) is calculated. The model is applied to numerical investigation of a problem of the high-current electron irradiation of Al, Cu, and Fe targets.
Band gap and refractive index tunability in thallium based layered mixed crystals
Authors: Gasanly N. M.
Published: July 2015

Compositional variation of the band gap energy and refractive index of TlMeX2-type (Me = Ga or In and X = S or Se) layered mixed crystals have been studied by the transmission and reflection measurements in the wavelength range of 400–1100 nm. The analysis of absorption data of TlGa1-xInxSe2, TlGa(S1−xSex)2, TlGa1−xInxS2, and TlIn(Se1−xSx)2 mixed crystals revealed the presence of both optical indirect and direct transitions. It was found that the energy band gaps of mixed crystals decrease at the replacing of gallium atoms by indium and of sulfur atoms by selenium ones. Through the similar replacing of atoms (smaller atoms by larger ones) in the studied mixed crystals, the refractive index shows the quite opposite behavior.
Preloaded freeplay wide-bandwidth low-frequency piezoelectric harvesters
Authors: Sharpes N. , Abdelkefi A. , Hajj M. R. , Heo J. , Cho K.-H. , Priya S.
Published: July 2015

We propose a technique for increasing the bandwidth of resonant low-frequency (<100 Hz) piezoelectric energy harvesters based on the modification of the clamped boundary condition of cantilevers, termed here as preloaded freeplay boundary condition. The effects of the preloaded freeplay boundary condition are quantified in terms of the fundamental frequency, frequency response, and power output for two beam configurations, namely, classical cantilevered bimorph piezoelectric energy harvester and zigzag unimorph piezoelectric energy harvester. A comparative analysis was performed between both the harvesters to empirically establish the advantages of the preloaded freeplay boundary condition. Using this approach, we demonstrate that the coupled degree-of-freedom dynamics results in an approximate 4–7 times increase in half-power bandwidth over the fixed boundary condition case.
Sub-millimeter resolution electrical conductivity images of brain tissues using magnetic resonance-based electrical impedance tomography
Authors: Oh Tong In , Kim Hyun Bum , Jeong Woo Chul , Sajib Saurav Z. K. , Kyung Eun Jung , Kim Hyung Joong , Kwon Oh In , Woo Eung Je
Published: July 2015

Recent magnetic resonance (MR)-based electrical impedance tomography (MREIT) of in vivo animal and human subjects enabled the imaging of electromagnetic properties, such as conductivity and permittivity, on tissue structure and function with a few millimeter pixel size. At those resolutions, the conductivity contrast might be sufficient to distinguish different tissue type for certain applications. Since the precise measurement of electrical conductivity under the tissue levels can provide alternative information in a wide range of biomedical applications, it is necessary to develop high-resolution MREIT technique to enhance its availability. In this study, we provide the experimental evaluation of sub-millimeter resolution conductivity imaging method using a 3T MR scanner combined with a multi-echo MR pulse sequence, multi-channel RF coil, and phase optimization method. From the phantom and animal imaging results, sub-millimeter resolution exhibited similar signal-to-noise ratio of MR magnitude and noise levels in magnetic flux density comparing to the existing millimeter resolution. The reconstructed conductivity images at sub-millimeter resolution can distinguish different brain tissues with a pixel size as small as 350 μm.
Investigating and engineering spin-orbit torques in heavy metal/Co2FeAl0.5Si0.5/MgO thin film structures
Authors: Loong Li Ming , Deorani Praveen , Qiu Xuepeng , Yang Hyunsoo
Published: July 2015

Current-induced spin-orbit torques (SOTs) have the potential to revolutionize magnetization switching technology. Here, we investigate SOT in a heavy metal (HM)/Co2FeAl0.5Si0.5 (CFAS)/MgO thin film structure with perpendicular magnetic anisotropy (PMA), where the HM is either Pt or Ta. Our results suggest that both the spin Hall effect and the Rashba effect contribute significantly to the effective fields in the Pt underlayer samples. Moreover, after taking the PMA energies into account, current-induced SOT-based switching studies of both the Pt and Ta underlayer samples suggest that the two HM underlayers yield comparable switching efficiency in the HM/CFAS/MgO material system.
Orientation control of epitaxial tetragonal Pb(ZrxTi1−x)O3 thin films grown on (100)KTaO3 substrates by tuning the Zr/(Zr + Ti) ratio
Authors: Ichinose Daichi , Nakashima Takaaki , Ehara Yoshitaka , Oikawa Takahiro , Shimizu Takao , Sakata Osami , Yamada Tomoaki , Funakubo Hiroshi
Published: July 2015

Pulsed metal organic chemical vapor deposition is used to epitaxially grow 30-nm thick tetragonal Pb(ZrxTi1−x)O3 thin films on (100) KTaO3 single crystal substrates. The in-plane misfit strain, which is controlled by the Zr/(Zr+Ti) ratio of Pb(ZrxTi1−x)O3 thin films, tunes the film orientation. When Zr/(Zr+Ti) = 0, which leads to the tensile strain from the substrate, a perfectly (100)-oriented film is formed, whereas when Zr/(Zr+Ti) = 0.45, which leads to the compressive strain from the substrate, a completely (001)-oriented film is realized. The volume fraction of the (001)-oriented domain almost linearly increases as the Zr/(Zr+Ti) ratio increases for films with (100) and (001) mixed orientations; this change in the volume fraction can be explained by considering the average lattice parameter matching between the Pb(ZrxTi1−x)O3 thin film and the KTaO3 substrate. These results demonstrate a method to systematically control the film orientation using the Zr/(Zr+Ti) ratio to tune the in-plane strain of Pb(ZrxTi1−x)O3 films grown on (100) KTaO3 single crystal substrates.
Energy band bowing parameter in MgZnO alloys
Authors: Wang Xu , Saito Katsuhiko , Tanaka Tooru , Nishio Mitsuhiro , Nagaoka Takashi , Arita Makoto , Guo Qixin
Published: July 2015

We report on bandgap bowing parameters for wurtzite and cubic MgZnO alloys from a study of high quality and single phase films in all Mg content range. The Mg contents in the MgZnO films were accurately determined using the energy dispersive spectrometer and X-ray photoelectron spectroscopy (XPS). The measurement of bandgap energies by examining the onset of inelastic energy loss in core-level atomic spectra from XPS is proved to be valid for determining the bandgap of MgZnO films. The dependence of the energy bandgap on Mg content is found to deviate downwards from linearity. Fitting of the bandgap data resulted in two bowing parameters of 2.01 ± 0.04 eV and 1.48 ± 0.11 eV corresponding to wurtzite and cubic MgZnO films, respectively.
Surface with recoverable mini structures made of shape-memory alloys for adaptive-control of boiling heat transfer
Authors: Wang Tao , Jiang Yu-Yan , Jiang Hai-Chang , Guo Cong , Guo Chao-Hong , Tang Da-Wei , Rong Li-Jian
Published: July 2015

A number of technologies have been developed to enhance boiling heat transfer (BHT). The enhancements of BHT depend on the size and geometry of the micro/mini structures and it seems difficult to design a structure that is optimum for all heat transfer conditions. This letter reports a study on adaptive control and enhancement of BHT by shape-memory alloy (SMA) structures. The experimental results of BHT on structured porous surfaces show that the SMA surface with recoverable structures has advantages for heat transfer both in the improvement of heat transfer coefficient and in the extending of operating range. The potential applications of such enhancement structures in diverse heat transfer devices are perhaps the most exciting.
Multi-quartz-enhanced photoacoustic spectroscopy
Authors: Ma Yufei , Yu Xin , Yu Guang , Li Xudong , Zhang Jingbo , Chen Deying , Sun Rui , Tittel Frank K.
Published: July 2015

A multi-quartz-enhanced photoacoustic spectroscopy (M-QEPAS) sensor system for trace gas detection is reported. Instead of a single quartz tuning fork (QTF) as used in QEPAS technique, a dual QTF sensor platform was adopted in M-QEPAS to increase the signal strength by the addition of the detected QEPAS signals. Water vapor was selected as the target analyte. M-QEPAS realized a 1.7 times signal enhancement as compared to the QEPAS method for the same operating conditions. A minimum detection limit of 23.9 ppmv was achieved for the M-QEPAS sensor, with a calculated normalized noise equivalent absorption coefficient of 5.95 × 10−8 cm−1W/√Hz. The M-QEPAS sensor performance can be further improved when more QTFs are employed or an acoustic micro-resonator architecture is used.
Biomimetic Method Synthesis of HgS/Polyurethane Composite Film and Its Sensing Properties to Ba2+
Authors: Wang Shan , Zheng Min-yan
Published: July 2015

Polyurethane-conjugated HgS nanocrystals with tunable sizes prepared by using biomimetic method. The obtained HgS nanoparticles with good dispersibility were characterized by Fourier transform infrared. Scanning electron microscopy are used to envisage the binding of nanoparticles with functional groups. The polyurethane molecules can control nucleation and growth of HgS crystals by binding on the surface of nanocrystals to stabilize nanoparticles. Quantum confinement effect of polyurethane-conjugated HgS nanocrystals was confirmed by UV-Vis spectra. The nanoparticles exhibit a well-defined emission feature at about 291 nm. The fluorescence results reveal that the PU/HgS nanoparticles film is sensitive to Ba2+, and a small amount of Ba2+ makes the emissions increase rapidly. The emission is hardly affected by other common ions in water. The nanocomposite film is possible to become a special sensor material for Ba2+.
Cascade Enzymatic Hydrolysis Coupling with Ultrafine Grinding Pretreatment for Sugarcane Bagasse Saccharification
Authors: Yuan Zheng-qiu , Long Jin-xing , Wang Tie-jun , Li Yu-qin , Zhang Qi , Ma Long-long
Published: July 2015

The biorefinery process for sugarcane bagasse saccharification generally requires significant accessibility of cellulose. We reported a novel method of cascade cellulase enzymatic hydrolysis coupling with ultrafine grinding pretreatment for sugarcane bagasse saccharification. Three enzymatic hydrolysis modes including single cellulase enzymatic hydrolysis, mixed cellulase enzymatic hydrolysis, and cascade cellulase enzymatic hydrolysis were compared. The changes on the functional group and surface morphology of bagasse during cascade cellulase enzymatic hydrolysis were also examined by FT-IR and SEM respectively. The results showed that cascade enzymatic hydrolysis was the most efficient way to enhance the sugarcane bagasse saccharification. More than 65% of reducing sugar yield with 90.1% of glucose selectivity was achieved at 50 °C, pH=4.8 for 72 h (1200 r/min) with cellulase I of 7.5 FPU/g substrate and cellulase II of 5 FPU/g substrate.
Populations of Ethanol Conformers in Liquid CCl4 and CS2 by Raman Spectra in OH Stretching Region
Authors: Hu Nai-yin , Lin Ke , Zhou Xiao-guo , Liu Shi-lin
Published: July 2015

Combining Raman spectroscopy with density functional theory, the populations of the trans- and gauche- ethanol conformers are investigated in carbon tetrachloride (CCl4) and carbon disulfide (CS2). The spectral contributions of two ethanol conformers are identified in OH stretching region. The energy difference between both conformers is estimated with the aid of the calculated Raman cross sections. It can be seen that the trans- ethanol is more stable in CCl4 and CS2 solutions. The spectra are also obtained at different temperatures, and it is found the van't Hoff analysis is invalid in these solutions. By taking accounts of the Boltzmann distribution and theoretical Raman cross section, the energy difference is found to be increased with temperature, which shows the weak intermolecular interactions can enhance the population of trans- ethanol.
Can wheat varietal mixtures buffer the impacts of water deficit?
Authors: Adu-Gyamfi Paul , Mahmood Tariq , Trethowan Richard
Published: July 2015

Moisture stress limits the yield and productivity of wheat, a staple food for 35% of the world’s population. The reproductive stage is the most vulnerable to moisture deficit, and genetic variation for tolerance to stress has been identified in the wheat gene pool. Introducing this complex variation into new, pure-line cultivars is difficult and time consuming. However, varietal mixtures can be an effective alternative to traditional gene pyramiding. Varietal mixtures lessen the impacts of abiotic and biotic stresses in two ways. First, they buffer yield through more efficient resource use, including soil moisture, particularly evident when mixtures comprise complementary physiological traits that influence water-use efficiency. Second, they improve resistance to root diseases and pests that limit root growth and subsequent access to, and absorption of, water from deeper in the soil profile. This review evaluates the concept of varietal mixtures and assesses their impact on crop productivity and environmental buffering. The potential of physiological and root disease resistance trait mixtures to stabilise yield is also explored. Avenues for developing compatible mixtures based on physiological traits that increase yield in water-limited environments are evaluated.
Factors supporting long-term culture of bovine male germ cells
Authors: Sahare Mahesh , Kim Sung-Min , Otomo Ayagi , Komatsu Kana , Minami Naojiro , Yamada Masayasu , Imai Hiroshi
Published: July 2015

Spermatogonial stem cells (SSCs) are unipotent in nature, but mouse SSCs acquire pluripotency under the appropriate culture conditions. Although culture systems are available for rodent and human germ-cell lines, no proven culture system is yet available for livestock species. Here, we examined growth factors, matrix substrates and serum-free supplements to develop a defined system for culturing primitive germ cells (gonocytes) from neonatal bovine testis. Poly-L-lysine was a suitable substrate for selective inhibition of the growth of somatic cells and made it possible to maintain a higher gonocyte : somatic cell ratio than those maintained with gelatin, collagen or Dolichos biflorus agglutinin (DBA) substrates. Among the serum-free supplements tested in our culture medium, knockout serum replacement (KSR) supported the proliferation and survival of gonocytes better than the supplements B-27 and StemPro-SFM after sequential passages of colonies. Under our optimised culture conditions consisting of 15% KSR supplement on poly-L-lysine-coated dishes, the stem-cell and germ-cell potentials of the cultured gonocytes were maintained with normal karyotype for more than 2 months (over 13 passages). The proposed culture system, which can maintain a population of proliferating bovine germ stem cells, could be useful for studying SSC biology and germline modifications in livestock animals.
Retinoic acid treatment alters germ cell heterogeneity and testicular echotexture in prepubescent ram lambs
Authors: Giffin Jennifer L. , Hahnel Ann C. , Bartlewski Pawel M.
Published: July 2015

Testicular echotextural attributes are closely associated with spermatogenic development; however, precise characterisation of specific germ cell types is difficult due to tremendous germ cell heterogeneity. Recently, retinoic acid (RA) administration in neonatal mice was found to induce highly synchronised spermatogenesis as adults. A RA-treatment protocol was tested in 17 ram lambs treated with or without RA at 8 weeks of age, with scrotal ultrasonography and blood samples collected until castration 24 h or 2.5 weeks later. At 8.2 weeks of age, the nuclear : seminiferous tubule (ST) area was higher in the treated compared with the control group. Serum testosterone concentrations and numerical pixel values (NPVs) of the testicular parenchyma reached a peak at 9 weeks of age in both groups of ram lambs studied. At 10.5 weeks of age, the percentage of ST cross-sections with different germ cells as the most mature germ cell type was lower and the inter-tubular heterogeneity and NPVs were also lower in the treated compared with the control animals. RA manipulation of spermatogenesis in prepubertal ram lambs may provide a suitable model for further investigation of the echotextural characteristics of specific germ cell types and critical developmental events.
Human domination of the biosphere: Rapid discharge of the earth-space battery foretells the future of humankind
Authors: Schramski John R. , Gattie David K. , Brown James H.
Published: July 2015

Earth is a chemical battery where, over evolutionary time with a trickle-charge of photosynthesis using solar energy, billions of tons of living biomass were stored in forests and other ecosystems and in vast reserves of fossil fuels. In just the last few hundred years, humans extracted exploitable energy from these living and fossilized biomass fuels to build the modern industrial-technological-informational economy, to grow our population to more than 7 billion, and to transform the biogeochemical cycles and biodiversity of the earth. This rapid discharge of the earth’s store of organic energy fuels the human domination of the biosphere, including conversion of natural habitats to agricultural fields and the resulting loss of native species, emission of carbon dioxide and the resulting climate and sea level change, and use of supplemental nuclear, hydro, wind, and solar energy sources. The laws of thermodynamics governing the trickle-charge and rapid discharge of the earth’s battery are universal and absolute; the earth is only temporarily poised a quantifiable distance from the thermodynamic equilibrium of outer space. Although this distance from equilibrium is comprised of all energy types, most critical for humans is the store of living biomass. With the rapid depletion of this chemical energy, the earth is shifting back toward the inhospitable equilibrium of outer space with fundamental ramifications for the biosphere and humanity. Because there is no substitute or replacement energy for living biomass, the remaining distance from equilibrium that will be required to support human life is unknown.
The LGI1–ADAM22 protein complex directs synapse maturation through regulation of PSD-95 function
Authors: Lovero Kathryn L. , Fukata Yuko , Granger Adam J. , Fukata Masaki , Nicoll Roger A.
Published: July 2015

Significance

The PSD-95 family proteins serve as central scaffolds of excitatory synapses. Their expression levels dictate synaptic strength, and the functions of many synaptic organizing molecules are dependent on interactions with these proteins. Yet, it is unclear what guides PSD-95 into maturing synapses, which occurs postnatally and is required for proper synapse development. Here, we establish that the secreted protein LGI1 controls the functional incorporation of PSD-95 through interactions with the transmembrane protein ADAM22. This process occurs in a paracrine fashion, with LGI1 released from the pre- and postsynaptic cell able to modulate postsynaptic strength. Our data illustrate a previously undescribed level of synaptic organization, identifying a critical role for the LGI1–ADAM22 complex in controlling the function of PSD-95 itself and, in turn, normal synapse development.
Inhibition of human neutrophil elastase by labdane diterpenes from the fruiting bodies ofRamaria formosa
Authors: Lee Ik-Soo , Kim Kwan-Chul , Yoo Ick-Dong , Ha Byung-Jo
Published: July 2015

Two new labdane diterpenes (1 and 2) were isolated from the fruiting bodies of Ramaria formosa. The structures of these compounds were established by extensive spectroscopic studies and chemical evidence. The inhibitory activity of compounds 1 and 2 against human neutrophil elastase (HNE) was evaluated in vitro. Compounds 1 and 2 inhibited HNE activity moderately. The IC50 values for compounds 1 and 2 were 36.4 ± 1.2 and 40.8 ± 1.5 μM, respectively; the IC50 value for the positive control, EGCG, was 12.5 ± 0.8 μM. In addition, the mechanism by which 2 inhibited HNE was a mixed-type noncompetitive inhibition, with a Ki of 41.5 ± 1.8 μM.
Initial insights on the biodiversity potential of biosolar roofs: a London Olympic Park green roof case study
Authors: Nash C. , Clough J. , Gedge D. , Lindsay R. , Newport D. , Ciupala M.A. , Connop S.
Published: July 2015

Cities dominated by impervious artificial surfaces can experience a multitude of negative environmental impacts. Restoration of green infrastructure has been identified as a mechanism for increasing urban resilience, enabling cities to transition towards sustainable futures in the face of climate-driven change. Building rooftops represent a viable space for integrating new green infrastructure into high-density urban areas. Urban rooftops also provide prime locations for photovoltaic (PV) systems. There is an increasing recognition that these two technologies can be combined to deliver reciprocal benefits in terms of energy efficiency and biodiversity targets. Scarcity of scientific evaluation of the interaction between PVs and green roofs means that the potential benefits are currently poorly understood. This study documents evidence from a biodiversity monitoring study of a substantial biosolar roof installed in the Queen Elizabeth Olympic Park. Vegetation and invertebrate communities were sampled and habitat structure measured in relation to habitat niches on the roof, including PV panels. Ninety-two plant species were recorded on the roof and variation in vegetation structure associated with proximity to PV panels was identified. Almost 50% of target invertebrate species collected were designated of conservation importance. Arthropod distribution varied in relation to habitat niches on the roof. The overall aim of the Main Press Centre building green roof design was to create a mosaic of habitats to enhance biodiversity, and the results of the study suggest that PV panels can contribute to niche diversity on a green roof. Further detailed study is required to fully characterise the effects of PV panel density on biodiversity.
Signal inhibition by a dynamically regulated pool of monophosphorylated MAPK
Authors: Nagiec Michal J. , McCarter Patrick C. , Kelley Joshua B. , Dixit Gauri , Elston Timothy C. , Dohlman Henrik G.
Published: July 2015

Protein kinases regulate a broad array of cellular processes and do so through the phosphorylation of one or more sites within a given substrate. Many protein kinases are themselves regulated through multisite phosphorylation, and the addition or removal of phosphates can occur in a sequential (processive) or a stepwise (distributive) manner. Here we measured the relative abundance of the monophosphorylated and dual-phosphorylated forms of Fus3, a member of the mitogen-activated protein kinase (MAPK) family in yeast. We found that upon activation with pheromone, a substantial proportion of Fus3 accumulates in the monophosphorylated state. Introduction of an additional copy of Fus3 lacking either phosphorylation site leads to dampened signaling. Conversely, cells lacking the dual-specificity phosphatase (msg5Δ) or that are deficient in docking to the MAPK-scaffold (Ste5ND) accumulate a greater proportion of dual-phosphorylated Fus3. The double mutant exhibits a synergistic, or “synthetic,” supersensitivity to pheromone. Finally, we present a predictive computational model that combines MAPK scaffold and phosphatase activities and is sufficient to account for the observed MAPK profiles. These results indicate that the monophosphorylated and dual-phosphorylated forms of the MAPK act in opposition to one another. Moreover, they reveal a new mechanism by which the MAPK scaffold acts dynamically to regulate signaling.
Conservation of inner nuclear membrane targeting sequences in mammalian Pom121 and yeast Heh2 membrane proteins
Authors: Kralt Annemarie , Jagalur Noorjahan B. , van den Boom Vincent , Lokareddy Ravi K. , Steen Anton , Cingolani Gino , Fornerod Maarten , Veenhoff Liesbeth M.
Published: July 2015

Endoplasmic reticulum–synthesized membrane proteins traffic through the nuclear pore complex (NPC) en route to the inner nuclear membrane (INM). Although many membrane proteins pass the NPC by simple diffusion, two yeast proteins, ScSrc1/ScHeh1 and ScHeh2, are actively imported. In these proteins, a nuclear localization signal (NLS) and an intrinsically disordered linker encode the sorting signal for recruiting the transport factors for FG-Nup and RanGTP-dependent transport through the NPC. Here we address whether a similar import mechanism applies in metazoans. We show that the (putative) NLSs of metazoan HsSun2, MmLem2, HsLBR, and HsLap2β are not sufficient to drive nuclear accumulation of a membrane protein in yeast, but the NLS from RnPom121 is. This NLS of Pom121 adapts a similar fold as the NLS of Heh2 when transport factor bound and rescues the subcellular localization and synthetic sickness of Heh2ΔNLS mutants. Consistent with the conservation of these NLSs, the NLS and linker of Heh2 support INM localization in HEK293T cells. The conserved features of the NLSs of ScHeh1, ScHeh2, and RnPom121 and the effective sorting of Heh2-derived reporters in human cells suggest that active import is conserved but confined to a small subset of INM proteins.
The Effect of Food Deserts on the Body Mass Index of Elementary Schoolchildren
Authors: Thomsen Michael R. , Nayga Rodolfo M. , Alviola Pedro A. , Rouse Heather L.
Published: July 2015

Families in low‐income neighborhoods sometimes lack access to supermarkets that provide a broad range of healthy foods. We investigate whether these so called “food deserts” play a role in childhood obesity using a statewide panel data set of Arkansas elementary schoolchildren. We use fixed‐effects panel data regression models to estimate the average food desert effect. We next compare children who left (entered) food deserts to children who were always (never) in food deserts and homogenize samples for those whose food desert status changed as a result of a change in residence and those whose status changed only as a consequence of the entry or exit of a supermarket. We present evidence that exposure to food deserts is associated with higher z‐scores for body mass index. On average, this is in the neighborhood of 0.04 standard deviations. The strongest evidence and largest association is among urban students and especially those that transition into food deserts from non‐deserts. Our food desert estimates are similar in magnitude to findings reported in earlier work on diet and lifestyle interventions targeting similarly aged schoolchildren. That said, we are unable to conclude that the estimated food desert effect is causal because many of the transitions into or out of food deserts result from a change in residence, an event that is endogenous to the child's household. However, there is evidence that food deserts are a risk indicator and that food desert areas may be obesogenic in ways that other low‐income neighborhoods are not.
A Bayesian approach for structure learning in oscillating regulatory networks
Authors: Trejo Banos Daniel , Millar Andrew J. , Sanguinetti Guido
Published: July 2015

Motivation: Oscillations lie at the core of many biological processes, from the cell cycle, to circadian oscillations and developmental processes. Time-keeping mechanisms are essential to enable organisms to adapt to varying conditions in environmental cycles, from day/night to seasonal. Transcriptional regulatory networks are one of the mechanisms behind these biological oscillations. However, while identifying cyclically expressed genes from time series measurements is relatively easy, determining the structure of the interaction network underpinning the oscillation is a far more challenging problem.

Results: Here, we explicitly leverage the oscillatory nature of the transcriptional signals and present a method for reconstructing network interactions tailored to this special but important class of genetic circuits. Our method is based on projecting the signal onto a set of oscillatory basis functions using a Discrete Fourier Transform. We build a Bayesian Hierarchical model within a frequency domain linear model in order to enforce sparsity and incorporate prior knowledge about the network structure. Experiments on real and simulated data show that the method can lead to substantial improvements over competing approaches if the oscillatory assumption is met, and remains competitive also in cases it is not.

Availability: DSS, experiment scripts and data are available at http://homepages.inf.ed.ac.uk/gsanguin/DSS.zip.

Contact: d.trejo-banos@sms.ed.ac.uk

Supplementary information:  Supplementary data are available at Bioinformatics online.
Epidemiology and Risk Factors for Ebola Virus Disease in Sierra Leone—23 May 2014 to 31 January 2015
Authors: Dietz Patricia M. , Jambai Amara , Paweska Janusz T. , Yoti Zabulon , Ksaizek Thomas G.
Published: July 2015

Background.  Sierra Leone has the most cases of Ebola virus disease (EVD) ever reported. Trends in laboratory-confirmed EVD, symptom presentation, and risk factors have not been fully described.

Methods.  EVD cases occurring from 23 May 2014 to 31 January 2015 are presented by geography, demographics, and risk factors for all persons who had laboratory-confirmed EVD, which was identified by Ebola virus–specific reverse-transcription polymerase chain reaction–based testing.

Results.  During the study period, 8056 persons had laboratory-confirmed EVD. Their median age was 28 years; 51.7% were female. Common symptoms included fever (90.4%), fatigue (88.3%), loss of appetite (87.0%), headache (77.9%), joint pain (73.7%), vomiting (71.2%), and diarrhea (70.6%). Among persons with confirmed cases, 47.9% reported having had contact with someone with suspected EVD or any sick person, and 25.5% reported having attended a funeral, of whom 66.2% reported touching the body. The incidence of EVD was highest during 1–30 November 2014, at 7.5 per 100 000 population per week, and decreased to 2.1 per week during 1–31 January 2015. Between 23 May and 30 August 2014, two districts had the highest incidence of 3.8 and 7.0 per 100 000 population per week which decreased >97% by 1–31 January 2015. In comparison, the districts that include the capital city reported a 10-fold increase in incidence per week during the same time periods.

Conclusions.  Almost half of patients with EVD in Sierra Leone reported physical contact with a person ill with EVD or a dead body, highlighting prevention opportunities.
Ground-based optical atomic clocks as a tool to monitor vertical surface motion
Authors: Bondarescu Ruxandra , Schärer Andreas , Lundgren Andrew , Hetényi György , Houlié Nicolas , Jetzer Philippe , Bondarescu Mihai
Published: July 2015

According to general relativity, a clock experiencing a shift in the gravitational potential ΔU will measure a frequency change given by Δf/f ≈ ΔU/c2. The best clocks are optical clocks. After about 7 hr of integration they reach stabilities of Δf/f ∼ 10−18 and can be used to detect changes in the gravitational potential that correspond to vertical displacements of the centimetre level. At this level of performance, ground-based atomic clock networks emerge as a tool that is complementary to existing technology for monitoring a wide range of geophysical processes by directly measuring changes in the gravitational potential. Vertical changes of the clock's position due to magmatic, post-seismic or tidal deformations can result in measurable variations in the clock tick rate. We illustrate the geopotential change arising due to an inflating magma chamber using the Mogi model and apply it to the Etna volcano. Its effect on an observer on the Earth's surface can be divided into two different terms: one purely due to uplift (free-air gradient) and one due to the redistribution of matter. Thus, with the centimetre-level precision of current clocks it is already possible to monitor volcanoes. The matter redistribution term is estimated to be 3 orders of magnitude smaller than the uplift term. Additionally, clocks can be compared over distances of thousands of kilometres over short periods of time, which improves our ability to monitor periodic effects with long wavelength like the solid Earth tide.
Introduction
Authors: Ladouceur Robert , Lachance Stella
Published: July 2015

Chapter 1 presents an introduction to both pathological gambling and the treatment program described in this guide. It outlines the diagnostic criteria for pathological gambling according to the DSM-IV-TR, the concepts and steps of this treatment program, including cognitive-behavioral therapy (CBT), and how the workbook will be used to support the treatment program.
Session 1
Authors: Ladouceur Robert , Lachance Stella
Published: July 2015

Chapter 3 outlines the first session of the treatment program. This session focuses on the client’s motivation to change, and to clarify the goals they have for the treatment. The importance of daily monitoring and record-keeping is discussed.
Sessions 2 & 3
Authors: Ladouceur Robert , Lachance Stella
Published: July 2015

Chapter 4 outlines sessions two and three of the treatment program. These sessions discuss the chains of events and risky situations that lead to excessive gambling, and aims to increase the client’s awareness of these situations so that avoidance strategies can be developed. Problem solving is also explored, using a five-step model.
Session 4
Authors: Ladouceur Robert , Lachance Stella
Published: July 2015

Chapter 5 discusses the fourth treatment session. This session focuses in detail on the client’s most recent gambling session, and aims to analyze the session by identify the erroneous thoughts that the client has before, during, and after gambling.
Sessions 11 & 12
Authors: Ladouceur Robert , Lachance Stella
Published: July 2015

Chapter 8 outlines treatment sessions 11 and 12, which focus on relapse. It aims to help the client understand that relapse is a normal process of a recovery progress, and teaches strategies that identify warning signs, and will help prevent slips or relapse. It also discusses actions to take in the case of relapse.
What can Gaia (with Thirty Meter Telescope) say about the Sculptor Dwarf's Core?
Authors: Evslin Jarah
Published: July 2015

Walker et al.'s Magellan/Michigan/MIKE Fiber System (MMFS) survey identified 1355 red giant candidates in the dwarf spheroidal galaxy Sculptor. We find that the Gaia satellite will be able to measure the proper motions of 139 of these with a precision of between 13 and 20 km s−1. Using a Jeans analysis and 5-parameter density model we show that this allows a determination of the mass within the deprojected half-light radius to within 16 per cent and a measurement of the dark matter density exponent γ to within 0.68 within that radius. If, even at first light, the Thirty Meter Telescope (TMT) observes Sculptor then the combined observations will improve the precision on these proper motions to about 5 km s−1, about 5 years earlier than would be possible without Gaia, further improving the precision of γ to 0.27. Using a bimodal stellar population model for Sculptor the precision of γ improves by about 30 per cent. This suggests that Gaia (with TMT) is capable of excluding a cusped profile of the kind predicted by CDM simulations with 2σ (4σ) of confidence.
SynCardia Portable Freedom Driver: A Single-Center Experience with 11 Patients
Authors: Shah Nilay R. , Jaroszewski Dawn E. , Ashfaq Awais , Schroedl Lucas A. , Staley Linda L. , Pajaro Octavio E. , Kasirajan Vigneshwar , Arabia Francisco A.
Published: July 2015

Objective

The portable Freedom Drive (SynCardia Inc, Tucson, AZ USA) for total artificial heart (TAH-t) support was approved for an investigational device exemption study in March 2010. We review our center's experience with the portable driver.

Methods

A retrospective review was conducted of patients who underwent TAH-t implantation and transfer to portable driver from September 2008 to June 2012, with follow-up through December 2012.

Results

A total of 30 patients underwent TAH-t implantation during this time period, with 11 patients successfully transferred to the Freedom Driver. Transfer to Freedom Driver after TAH-t implant was a median of 46 days (range, 225–86 days). Ninety-one percent (10) of 11 patients transferred to Freedom Driver were bridged to transplantation. One patient died on support. Five (45.5%) of 11 patients were discharged home and 5 (45.5%) remained in-patient on the portable driver before transplantation. Four patients (80%) successfully discharged home required at least 1 hospital readmission (range, 1–5 admissions per patient). Six patients (55%) transferred to the portable driver required a return to a main driver console. Two patients were temporarily maintained on the main driver then returned to the Freedom Driver for bridge to transplantation.

Conclusions

Patients with TAH-t can be considered for transfer to the portable Freedom Driver while awaiting transplantation. Issues that complicated this patient population included inadequate social support, hemodynamic instability, and concurrent morbidities. The potential benefits of the portable driver are currently undergoing assessment. These may include increased mobility and improved quality of life, opportunity for discharge home, and decreased overall medical costs.