bluuebunny/crossref_metadata_2025 huggingface dataset:
Theory of interactions of thin strong detonations with turbulent gases
Authors: Huete César , Sánchez Antonio L. , Williams Forman A.
Published: August 2013

We present the exact small-amplitude linear Laplace-transform theory describing the propagation of an initially planar detonation front through a gaseous mixture with nonuniform density perturbations, complementing earlier normal-mode results for nonuniform velocity perturbations. The investigation considers the fast-reaction limit in which the detonation thickness is much smaller than the size of the density perturbations, so that the detonation can be treated as an infinitesimally thin front with associated jump conditions given by the Rankine-Hugoniot equations. The analytical development gives the exact transient evolution of the detonation front and the associated disturbance patterns generated behind for a single-mode density field, including explicit expressions for the distributions of density, pressure, and velocity. The results are then used in a Fourier analysis of the detonation interaction with two-dimensional and three-dimensional isotropic density fields to provide integral formulas for the kinetic energy, enstrophy, and density amplification. Dependencies of the solution on the heat-release parameter and propagation Mach number are discussed, along with differences and similarities with results of previous analyses for non-reacting shock waves.
Scaling analysis of bio-molecular dynamics derived from elastic incoherent neutron scattering experiments
Authors: Doster W. , Nakagawa H. , Appavou M. S.
Published: August 2013

Numerous neutron scattering studies of bio-molecular dynamics employ a qualitative analysis of elastic scattering data and atomic mean square displacements. We provide a new quantitative approach showing that the intensity at zero energy exchange can be a rich source of information of bio-structural fluctuations on a pico- to nano-second time scale. Elastic intensity scans performed either as a function of the temperature (back-scattering) and/or by varying the instrumental resolution (time of flight spectroscopy) yield the activation parameters of molecular motions and the approximate structural correlation function in the time domain. The two methods are unified by a scaling function, which depends on the ratio of correlation time and instrumental resolution time. The elastic scattering concept is illustrated with a dynamic characterization of alanine-dipeptide, protein hydration water, and water-coupled protein motions of lysozyme, per-deuterated c-phycocyanin (CPC) and hydrated myoglobin. The complete elastic scattering function versus temperature, momentum exchange, and instrumental resolution is analyzed instead of focusing on a single cross-over temperature of mean square displacements at the apparent onset temperature of an-harmonic motions. Our method predicts the protein dynamical transition (PDT) at Td from the collective (α) structural relaxation rates of the solvation shell as input. By contrast, the secondary (β) relaxation enhances the amplitude of fast local motions in the vicinity of the glass temperature Tg. The PDT is specified by step function in the elastic intensity leading from elastic to viscoelastic dynamic behavior at a transition temperature Td.
Modulational interactions in quantum plasmas
Authors: Sayed F. , Vladimirov S. V. , Tyshetskiy Yu. , Ishihara O.
Published: August 2013

A formalism for treating modulational interactions of electrostatic fields in collisionless quantum plasmas is developed, based on the kinetic Wigner-Poisson model of quantum plasma. This formalism can be used in a range of problems of nonlinear interaction between electrostatic fields in a quantum plasma, such as development of turbulence, self-organization, as well as transition from the weak turbulent state to strong turbulence. In particular, using this formalism, we obtain the kinetic quantum Zakharov equations that describe nonlinear coupling of high frequency Langmuir waves to low frequency plasma density variations, for cases of non-degenerate and degenerate plasma electrons.
Low field induced giant magnetocaloric effect in TmGa compound
Authors: Mo Zhao-Jun , Shen Jun , Yan Li-Qin , Tang Cheng-Chun , Lin Jing , Wu Jian-Feng , Sun Ji-Rong , Wang Li-Chen , Zheng Xin-Qi , Shen Bao-Gen
Published: August 2013

The magnetic properties and magnetocaloric effect in TmGa compound are investigated. TmGa exhibits two successive magnetic transitions: ferromagnetic-antiferromagnetic at TFA = 12 K and antiferromagnetic-paramagnetic transition at TN = 15 K. Under field changes of 1 and 2 T, giant reversible values of magnetic entropy change (12.9 and 20.6 J/kg K) and large values of refrigerant capacity (69 and 149 J/kg) are observed, respectively. Additionally, the maximal values of adiabatic temperature change are 3.2 and 5 K for field changes of 1 and 2 T, respectively. The TmGa compound with excellent magnetocaloric effect is expected to have effective applications in low temperature magnetic refrigeration.
A microscopic formulation of the phonon transmission at the nanoscale
Authors: Chalopin Y. , Volz S.
Published: August 2013

We present a microscopic approach for estimating the frequency vs. wave-vector dependent phonon transmission across a solid-solid interface. We show that the spectral properties of the heat flux can be generally deduced from the equilibrium displacements fluctuations of the contact atoms. We have applied and demonstrated our formalism with molecular dynamics simulations to predict the angular and mode dependent phonon transport in silicon and germanium thin films. This notably unveils the existence of confined interface mode at the thermal contacts.
CdTe microwire-based ultraviolet photodetectors aligned by a non-uniform electric field
Authors: Park Hyunik , Yang Gwangseok , Chun Seungju , Kim Donghwan , Kim Jihyun
Published: August 2013

We report on ultraviolet (UV) photodetectors fabricated by positioning Cadmium Telluride (CdTe) microwires (μWs) precisely by dielectrophoretic (DEP) force, where CdTe μWs were grown using an Au-catalyst-assisted closed-space-sublimation (CSS) method. The optical properties of CSS-grown CdTe μWs were characterized by micro-photoluminescence and micro-Raman spectroscopies. Optoelectronic characteristics were obtained after CdTe μWs were aligned on a pre-patterned SiO2/Si substrate by a non-uniform electric field. Photocurrents were increased with increasing the light intensities. Fast and reliable photoresponse and recovery were observed when CdTe μWs were exposed to UV illuminations. We demonstrated that high quality CdTe μWs grown by the CSS method have significant potentials as optoelectronic devices.
First-principles study of valence band offsets at ZnSnP2/CdS, ZnSnP2/ZnS, and related chalcopyrite/zincblende heterointerfaces
Authors: Hinuma Yoyo , Oba Fumiyasu , Nose Yoshitaro , Tanaka Isao
Published: August 2013

The valence band offsets of chalcopyrite ZnSnP2 (ZSP), CdSnP2 (CSP), CuInSe2 (CIS), and CuGaSe2 (CGS) against zincblende CdS and ZnS are obtained using first-principles calculations based on hybrid density functional theory. The ZSP-CSP (ZCSP) alloy is isostructural to the CIS-CGS (CIGS) alloy and is known for its potential usage in photovoltaic applications. Therefore, the band offsets with other semiconductors, such as CdS and ZnS, are important. The calculated valence band offsets are ∼1.0 eV for ZSP/CdS and CSP/CdS, ∼1.2 eV for ZSP/ZnS and CSP/ZnS, ∼1.2 eV for CIS/CdS and CGS/CdS, and ∼1.3 eV for CIS/ZnS and CGS/ZnS. The CdS/ZnS valence band offset is within 0.1 eV. Transitivity of natural valence band offsets in the investigated semiconductors holds within ∼0.1 eV, which is smaller than the error in band alignment of ∼0.2 eV when ionization potential differences are used. The ZSP-CSP and CIS-CGS systems have similar valence and conduction band positions, which is an important piece of information for band offset engineering in the development of photovoltaics using ZCSP alloys.
Dissimilar-electrodes-induced asymmetric characteristic and diode effect of current transport in zinc oxide tunnel junctions
Authors: Zhang Genghong , Zheng Yue , Wang Biao
Published: August 2013

Based on the first principles simulations and quantum transport calculations, effects of dissimilar electrodes and interfaces on the current transport and relevant electrical properties in ZnO tunnel junctions as well as the mechanism of current asymmetric characteristic adjustment have been investigated. Our results show that the potential energy, built-in electric field, electron transmission probability, current, etc. in ZnO tunnel junctions can be tailored by adopting asymmetric electrode combinations. By adopting dissimilar electrodes to fabricate different potential barriers, we have performed manipulations on current transport in ZnO tunnel junctions and realized the enhancement and even the reversal of the current asymmetric characteristic. We also demonstrate that it is the different potential energy levels of the dissimilar electrodes in asymmetric tunnel junctions playing an important role in the adjustment of current asymmetry, which is innovative and different from the mechanism of current asymmetry adjustment through strain-induced piezopotential reversal. This investigation exhibits a novel and significant method for controlling or modifying the performances of electronic devices by utilizing dissimilar electrodes.
Self-similar space-time evolution of an initial density discontinuity
Authors: Rekaa V. L. , Pécseli H. L. , Trulsen J. K.
Published: August 2013

The space-time evolution of an initial step-like plasma density variation is studied. We give particular attention to formulate the problem in a way that opens for the possibility of realizing the conditions experimentally. After a short transient time interval of the order of the electron plasma period, the solution is self-similar as illustrated by a video where the space-time evolution is reduced to be a function of the ratio x/t. Solutions of this form are usually found for problems without characteristic length and time scales, in our case the quasi-neutral limit. By introducing ion collisions with neutrals into the numerical analysis, we introduce a length scale, the collisional mean free path. We study the breakdown of the self-similarity of the solution as the mean free path is made shorter than the system length. Analytical results are presented for charge exchange collisions, demonstrating a short time collisionless evolution with an ensuing long time diffusive relaxation of the initial perturbation. For large times, we find a diffusion equation as the limiting analytical form for a charge-exchange collisional plasma, with a diffusion coefficient defined as the square of the ion sound speed divided by the (constant) ion collision frequency. The ion-neutral collision frequency acts as a parameter that allows a collisionless result to be obtained in one limit, while the solution of a diffusion equation is recovered in the opposite limit of large collision frequencies.
Ferromagnetic Schottky junctions using half-metallic Co2MnSi/diamond heterostructures
Authors: Ueda K. , Soumiya T. , Nishiwaki M. , Asano H.
Published: August 2013

We demonstrate half-metallic Heusler Co2MnSi films epitaxially grown on diamond semiconductors using the ion-beam assisted sputtering method. Lower temperature growth below ∼400 °C is key for obtaining abrupt Co2MnSi/diamond interfaces. The Co2MnSi films on diamond showed a negative anisotropic magnetoresistance of ∼0.2% at 10 K, suggesting the half-metallic nature of the Co2MnSi films. Schottky junctions formed using the Co2MnSi/diamond heterostructures at 400 °C showed clear rectification properties with a rectification ratio of ∼103. The Schottky barrier heights of the Co2MnSi/diamond interfaces were estimated to be ∼0.8 eV. These results indicate that Co2MnSi is a promising spin source for spin injection into diamond.
Bulge test at nano-scale: The surface effects
Authors: Lu Tongqing , Chen Chao , Zhao Kejie , Zhang Weixu , Wang T. J.
Published: August 2013

Bulge test is an effective technique to measure the mechanical properties of thin films. As the membrane size decreases to nano-scale, the surface effect plays a significant role in determining the mechanical behavior of the membrane, and the techniques commonly used to measure the bulk materials properties are not applicable. We explore the surface effect on the nano-scale bulge test using combined continuum theories and atomistic simulations. We formulate the load-deflection relation by incorporating the surface effect and analyze its size-dependent behavior. The present theoretical model is in quantitative agreement with the molecular dynamics simulations.
Intrinsically stable light source at telecom wavelengths
Authors: Monteiro Fernando , Guerreiro Thiago , Sanguinetti Bruno , Zbinden Hugo
Published: August 2013

We present a highly stable light source at telecom wavelengths, based on a short erbium doped fiber. The high stability arises from the high inversion of the Er3+ ion population. This source is developed to work as a stable reference in radiometric applications and is useful in any application where high stability and/or a large bandwidth are necessary. The achieved long-term stability is 10 ppm.
Radius-voltage relation of graphene bubbles controlled by gate voltage
Authors: Mu Weihua , Zhang Gang , Ou-Yang Zhong-can
Published: August 2013

Graphene on the substrate can form bubbles rising above the sheet. In some cases, the bubbles is a perfect spherical surface crown, and its radius can be adjusted by external electric field. In this manuscript, we theoretically investigate the voltage dependence of the spherical bubble's radius. The calculated results are in good agreement with recent experiments on the graphene bubble controlled by applied gate voltage [Georgiou et al., Appl. Phys. Lett. 99, 093103 (2011)].
Nanoplasmonic distributed Bragg reflector resonators for monolithic integration on a complementary metal-oxide-semiconductor platform
Authors: Nielsen M. P. , Elezzabi A. Y.
Published: August 2013

We present nanoplasmonic Au/SiO2/Si metal-insulator-semiconductor distributed Bragg reflector resonators capable of broadband operation and with the potential for monolithic integration with complementary metal-oxide-semiconductor technology. With a compact device footprint as small as 1.5 μm2 and quality factors as high as 64.4 at λ = 1.545 μm, these resonators have the highest quality factor over device footprint figure of merit yet demonstrated for a silicon nanoplasmonic device. A higher quality factor is shown to be achievable by using smaller gaps in the Bragg reflectors.
Synthesis and characterization of specific electrode materials for solar cells and supercapacitors
Authors: Stević Z. , Radovanović I. , Rajčić-Vujasinović M. , Bugarinović S. , Grekulović V.
Published: August 2013

In this paper a brief overview of research in the field of electrode materials for solar cells and supercapacitors is presented, which the authors dealt with for years. In addition to the standard electrode material (graphite and silicon in supercapacitor with solar cells), different materials were examined, particularly oxides and sulfides of copper. Copper (I) oxide or cuprous oxide is an oxide semiconductor which is used as the anodic material in the form of thin film in lithium batteries and solar cells. The cathodic process of synthesis of cuprous oxide thin film is carried out in a potentiostatic mode from the organic electrolyte. The electrochemical characterization was carried out by cyclic voltammetry. The electro deposition techniques are particularly well suited for the deposition of single elements, but it is also possible to carry out simultaneous depositions of several elements and syntheses of well-defined alternating layers of metals and oxides with thicknesses down to a few nanometers. Electrochemical characteristics of covellite (CuS) are of importance from flotation and metallurgical point of view, due to its potential application in solid state solar cells and in photocatalytic reactions. Also, the compound CuS appears as an intermediary product or a final product in electrochemical oxidation reactions of chalcocite (Cu2S) which exhibits supercapacitor characteristics. Natural copper mineral covellite has been investigated in inorganic sulfate acid electrolytes, as well as in strong alkaline electrolyte. Different electrochemical methods (galvanostatic, potentiostatic, cyclic voltammetry, and electrochemical impedance spectroscopy) have been used in these investigations.
Ultrasound measurements reveal a long-sought phase transition in superconducting cuprates
Authors: Miller Johanna L.
Published: August 2013

Vibrational resonances provide a sensitive probe into the materials’ thermodynamic properties.
X-ray diffraction details water’s path through a cell pore
Authors: Smart Ashley G.
Published: August 2013

A high-resolution crystallographic structure reveals why aquaporin proteins are permeable to water but not to protons.
Livermore program accelerates cancer diagnostics
Authors: Kramer David
Published: August 2013

Lasers could eventually replace accelerator mass spectrometry for many biomedical applications, but they haven’t yet.
An Analysis of Usage of Different Types of Visualisation Media within a Collaborative Planning Workshop Environment
Authors: Gill Lewis , Lange Eckart , Morgan Ed , Romano Daniela
Published: August 2013

Within the planning process, there is a recent trend to engage with stakeholders. Traditionally, visualisation media such as plans, sections, and physical models have been used to aid communication of planning proposals, yet technological advances now allow for virtual interactive, three-dimensional visualisations of proposals to be created. It is unclear whether these new technologies will usurp or augment the more traditional media. In an experimental setting, a set of participants in a collaborative planning workshop were introduced to a range of different visualisation media for a riverside flood-defence proposal and asked to discuss the proposal. Video recordings were made of the workshop and a questionnaire was completed by each participant. A method for capturing the time usage of each media type is presented. This shows that plans and interactive eye-level walkthroughs were the most used media types, but that user-based assessment of media might not match observed usage. These results lead to a discussion about visualisation media that should be created and further research to support the participatory planning process.
Local Hedonic House-Price Modelling for Urban Planners: Advantages of Using Local Regression Techniques
Authors: Crespo Ricardo , Grêt-Regamey Adrienne
Published: August 2013

Hedonic house-price models have long been used in urban studies to investigate important factors characterizing cities (eg, the demand for amenities or housing submarkets). Traditionally, the formulation of hedonic models has been solved using global spatial econometric techniques. The development of local regression methods brought new insights into urban planning as the relationships between house prices and their determinants can be estimated locally and therefore mapped across space. Such maps provide planners and policy makers with valuable location-specific information to support their decision-making processes. A feature that is frequently overlooked when performing spatial local analysis is testing the statistical significance of local parameter estimates over space. This can be done by mapping the t-value of parameter estimates ( t-surfaces). In this study we propose the use of a mixed geographically weighted regression (mixed-GWR) technique to estimate a hedonic house-price model in Zurich. Mixed-GWR is an extended version of GWR by which some parameters are allowed to vary over space, while others remained fixed. To obtain spatially explicit results in a more meaningful way, we propose the use of t-surfaces to explore the statistical significance of selected local parameter estimates over space. We also follow the Bonferroni correction to overcome the problem of multiple hypothesis testing in local regression modelling. Results reveal interesting patterns in the spatial variability of local estimates for planners. For instance, areas are identified over which public policies such as house taxing have little or no effect on house pricing. Similarly, economic distortions in the housing market can be examined through the variability of residents' willingness to pay for larger dwellings. Also, urban development processes such as densification of cities can be supported by spatially exploring relevant socioeconomic variables.
Adaptive and Strategic Capacity: Navigating Megaprojects through Uncertainty and Complexity
Authors: Giezen Mendel
Published: August 2013

In an effort to combat the complexity and uncertainty that comes with mega-infrastructure development, planners often seek to simplify the process and scope of their projects, making plans that consist of rigid sequential steps. The question is how this approach influences planners' responsiveness to uncertainty and complexity in megaproject decision making and planning. To answer this question I introduce two concepts: Adaptive capacity and strategic capacity. I develop these concepts and apply them to three large infrastructure projects in the Netherlands in order to analyze the potential of these projects to deal with change and inertia. In this paper I first look at the concepts individually and then link them together. This shows that, to be successful, planning needs to navigate a project through uncertainty and complexity and that it is important that these concepts are taken into consideration.
Planning Health-Promoting Development: Creation and Assessment of an Evidence-Based Index in the Region of Peel, Canada
Authors: Weyman Jonathan Toshach , Dunn James R , Gutmann Christine , Sivanand Bhavna , Bursey Gayle , Mowat David L
Published: August 2013

There is mounting evidence of relationships between the built environment, health behaviours, and chronic disease. Collaborative intervention efforts aimed at improving sustainability and environmental planning are underway in many jurisdictions, but relatively few have focused on the rationale and evidence for health-promoting development. Given current rates of chronic diseases, such as diabetes, a collaborative effort between planning departments, public health professionals, and researchers was undertaken to create an evidence-based healthy development index aimed at encouraging health-promoting development in the municipality of the Region of Peel, ON, Canada. In this paper we present the review process used to establish prerequisite elements and measures in the index, and the spatial analytical methodology developed to assess these measures within existing neighbourhoods in our setting. The assessment process and results offer important insight into barriers in existing design standards, official plan policies, zoning by-laws, and technical requirements that limit health-promoting development and have hindered implementation of the index as a tool for planning policy. Our discussion highlights challenges that those seeking to undertake similar interventions in other rapidly developing suburban jurisdictions may encounter. Despite barriers to implementation of the index in the form originally intended, a variety of positive policy contributions have been made in municipal and provincial jurisdictions as a result of this work. Further study is needed to identify and address detailed barriers to policy implementation, and to document the longitudinal health impacts associated with this built environment intervention
The Effect of Different Clay Dispersion Methods on the Properties of Polyurethane/Clay Nanocomposites
Authors: Sin Sau Leng , Kumar Jatin Nitin , Tan Hui Ru , He Chaobin , Liu Ye , Xu Jianwei
Published: August 2013

Polyurethane/clay (PU/clay) nanocomposites were synthesised using polymerisation and dispersion blending methods. The intercalation and exfoliation properties of the PU/clay nanocomposites were investigated by X-ray diffraction and transmission electron microscope. Clay intercalation of polymerised PU/nanocomposites was achieved and the interlayer spacing of clay was greatly enlarged from 17 Å to ~30 Å. Expansion in d-spacing was also observed for PU/clay nanocomposites prepared using dispersion methods. PU/clay nanocomposites prepared from dispersion of clay particles in the prepolymer matrix, followed by chain extension reaction, showed much high molecular weight and significant improvement in mechanical properties as compared with PU/clay nanocomposites produced using polymerisation or a simple high speed blending method in which clay was blended into the PU matrix. For PU/clay nanocomposites prepared using the blending method, high speed dispersion of 2 % clay in PU resulted in approximately a two-fold increase in the Young’s modulus. Further increase in the clay loading from 2 to 6 % made the corresponding nanocomposite polymer films more rigid and stiffer. This study shows that PU/clay nanocomposite properties are highly dependent on the preparation methods and provides useful guidelines for the future design and preparation of PU/clay nanocomposites.
Stimuli-Responsive Films Based on N-Substituted Polyurethane with Different Alkyl Length
Authors: Wang Yanyan , Liu Libin , Qiao Congde , Li Tianduo
Published: August 2013

N-Alkyl-substituted polyurethanes with different alkyl chain lengths were prepared from the corresponding bromoalkane (1-bromooctane, 1-bromotetradecane, and 1-bromooctadecane) and polyurethane consisting of poly(propylene glycol) (PPG), 4,4′-diphenylmethane diisocyanate, and 1,4-butanediol. The synthesised materials were characterised by 1H NMR and FTIR spectroscopy and the degrees of substitution were discussed by changing the reaction conditions. Differential scanning calorimetry and X-ray diffraction were used to characterise the thermal properties and crystalline state. Microphase-separated nanostructures, with hard segments (nanofibre-like) embedded into amorphous PPG soft segments, are observed by atomic force microscopy and scanning electron microscopy. A reversible behaviour of the films was revealed by contact angle measurement. Stimuli-responsive films were realised by solvent vapour annealing and heat treatment, and exhibited a reversible switching in surface wettability with a remarkable change in the water contact angle of 21°.
Medicine use and safety while breastfeeding: investigating the perspectives of community pharmacists in Australia
Authors: de Ponti Martine , Stewart Kay , Amir Lisa H. , Hussainy Safeera Y.
Published: August 2013

Consumers and health professionals rely on community pharmacists for accurate information about the safety of medicines. Many breastfeeding women require medications, yet we know little about the advice provided to them by pharmacists in Australia. The aim of this study therefore was to investigate the perspectives of community pharmacists in Australia on medication use and safety in breastfeeding using a postal survey of a national random sample of 1166 community pharmacies in 2011. One hundred and seventy-six pharmacists responded (51% female). Of the 52% of participants with children, many (70%) had a total breastfeeding duration (self or partner) of 27 weeks or more. The majority (92%) were confident about supplying or counselling on medication during breastfeeding. The most commonly used resources were drug company information, Australian Medicines Handbook and the Royal Women’s Pregnancy and Breastfeeding Medicine Guide. Most (80%) believed the available information to be adequate and 86% thought it accessible. Over one-third were unaware that ibuprofen and metronidazole are compatible with breastfeeding. Most (80%) were able to name at least one medicine that may decrease milk supply. We found that community pharmacists discuss medicine use in lactation and are confident of their ability to do so; however, their knowledge may be variable.
Effects of castration on androgen receptors and gonadotropins in the pituitary of adult male viscachas
Authors: Filippa Verónica , Godoy Daiana , Perez Edith , Mohamed Fabian
Published: August 2013

The aims of the present study were to determine whether castration results in quantitative immunohistochemical changes in androgen receptors (AR), LH-immunoreactive (IR) cells and FSH-IR cells, and to analyse the colocalisation of AR and gonadotropins in the pituitary pars distalis (PD) of viscachas. Pituitaries were processed for light and electron microscopy. AR-IR, LH-IR and FSH-IR cells were detected by immunohistochemistry. In morphometric studies, the percentage of AR-IR, LH-IR, FSH-IR, LH-IR/AR-IR and FSH-IR/AR-IR cells was determined. In intact viscachas, AR were distributed throughout the PD; they were numerous at the caudal end, with intense immunostaining. LH-IR cells and FSH-IR cells were found mainly in the ventral region and at the rostral end of the PD. Approximately 45%–66% of LH-IR cells and 49%–57% of FSH-IR cells expressed AR in the different zones of the PD. In castrated viscachas, there was a significant decrease in the percentage of AR-IR, LH-IR, FSH-IR, and FSH-IR/AR-IR cells. Some pituitary cells from castrated viscachas also exhibited ultrastructural changes. These results provide morphological evidence that gonadal androgens are directly related to the immunolabelling of AR, LH and FSH. Moreover, the colocalisation of AR and FSH is most affected by castration, suggesting the existence of a subpopulation of gonadotrophs with different regulatory mechanisms for hormonal synthesis, storage and secretion.
Neuronal prostaglandin E
2
receptor subtype EP3 mediates antinociception during inflammation
Authors: Natura Gabriel , Bär Karl-Jürgen , Eitner Annett , Boettger Michael K. , Richter Frank , Hensellek Susanne , Ebersberger Andrea , Leuchtweis Johannes , Maruyama Takayuki , Hofmann Gunther Olaf , Halbhuber Karl-Jürgen , Schaible Hans-Georg
Published: August 2013

The pain mediator prostaglandin E
2
(PGE
2
) sensitizes nociceptive pathways through EP2 and EP4 receptors, which are coupled to G
s
proteins and increase cAMP. However, PGE
2
also activates EP3 receptors, and the major signaling pathway of the EP3 receptor splice variants uses inhibition of cAMP synthesis via G
i
proteins. This opposite effect raises the intriguing question of whether the G
i
-protein–coupled EP3 receptor may counteract the EP2 and EP4 receptor-mediated pronociceptive effects of PGE
2
. We found extensive localization of the EP3 receptor in primary sensory neurons and the spinal cord. The selective activation of the EP3 receptor at these sites did not sensitize nociceptive neurons in healthy animals. In contrast, it produced profound analgesia and reduced responses of peripheral and spinal nociceptive neurons to noxious stimuli but only when the joint was inflamed. In isolated dorsal root ganglion neurons, EP3 receptor activation counteracted the sensitizing effect of PGE
2
, and stimulation of excitatory EP receptors promoted the expression of membrane-associated inhibitory EP3 receptor. We propose, therefore, that the EP3 receptor provides endogenous pain control and that selective activation of EP3 receptors may be a unique approach to reverse inflammatory pain. Importantly, we identified the EP3 receptor in the joint nerves of patients with painful osteoarthritis.
Self-integration of nanowires into circuits via guided growth
Authors: Schvartzman Mark , Tsivion David , Mahalu Diana , Raslin Olga , Joselevich Ernesto
Published: August 2013

The ability to assemble discrete nanowires (NWs) with nanoscale precision on a substrate is the key to their integration into circuits and other functional systems. We demonstrate a bottom–up approach for massively parallel deterministic assembly of discrete NWs based on surface-guided horizontal growth from nanopatterned catalyst. The guided growth and the catalyst nanopattern define the direction and length, and the position of each NW, respectively, both with unprecedented precision and yield, without the need for postgrowth assembly. We used these highly ordered NW arrays for the parallel production of hundreds of independently addressable single-NW field-effect transistors, showing up to 85% yield of working devices. Furthermore, we applied this approach for the integration of 14 discrete NWs into an electronic circuit operating as a three-bit address decoder. These results demonstrate the feasibility of massively parallel “self-integration” of NWs into electronic circuits and functional systems based on guided growth.
Lattice effects on ferromagnetism in perovskite ruthenates
Authors: Cheng J.-G. , Zhou J.-S. , Goodenough John B.
Published: August 2013

Ferromagnetism and its evolution in the orthorhombic perovskite system Sr
1–x
Ca
x
RuO
3
have been widely believed to correlate with structural distortion. The recent development of high-pressure synthesis of the Ba-substituted Sr
1–y
Ba
y
RuO
3
makes it possible to study ferromagnetism over a broader phase diagram, which includes the orthorhombic
Imma
and the cubic phases. However, the chemical substitutions introduce the A-site disorder effect on T
c
, which complicates determination of the relationship between ferromagnetism and structural distortion. By clarifying the site disorder effect on T
c
in several unique series of ruthenates in which the average bond length 〈A–O〉 remains the same but the bond-length variance varies, we are able to demonstrate a parabolic curve of T
c
versus mean bond length 〈A–O〉. A much higher T
c
∼ 177 K than that found in orthorhombic SrRuO
3
can be obtained from the curve at a bond length 〈A–O〉, which makes the geometric factor t = 〈A–O〉/(√2〈Ru–O〉) ∼ 1. This result reveals not only that the ferromagnetism in the ruthenates is extremely sensitive to the lattice strain, but also that it has an important implication for exploring the structure–property relationship in a broad range of oxides with perovskite or a perovskite-related structure.
Multibranch activity in basal and tuft dendrites during firing of layer 5 cortical neurons in vivo
Authors: Hill Daniel N. , Varga Zsuzsanna , Jia Hongbo , Sakmann Bert , Konnerth Arthur
Published: August 2013

Layer 5 pyramidal neurons process information from multiple cortical layers to provide a major output of cortex. Because of technical limitations it has remained unclear how these cells integrate widespread synaptic inputs located in distantly separated basal and tuft dendrites. Here, we obtained in vivo two-photon calcium imaging recordings from the entire dendritic field of layer 5 motor cortex neurons. We demonstrate that during subthreshold activity, basal and tuft dendrites exhibit spatially localized, small-amplitude calcium transients reflecting afferent synaptic inputs. During action potential firing, calcium signals in basal dendrites are linearly related to spike activity, whereas calcium signals in the tuft occur unreliably. However, in both dendritic compartments, spike-associated calcium signals were uniformly distributed throughout all branches. Thus, our data support a model of widespread, multibranch integration with a direct impact by basal dendrites and only a partial contribution on output signaling by the tuft.
Experiences of Marijuana-Vaporizer Users
Authors: Malouff John M. , Rooke Sally E. , Copeland Jan
Published: August 2013

Background

Using a marijuana vaporizer may have potential harm-reduction advantages on smoking marijuana, in that the user does not inhale smoke. Little research has been published on use of vaporizers.

Methods

In the first study of individuals using a vaporizer on their own initiative, 96 adults anonymously answered questions about their experiences with a vaporizer and their use of marijuana with tobacco.

Results

Users identified 4 advantages to using a vaporizer over smoking marijuana: perceived health benefits, better taste, no smoke smell, and more effect from the same amount of marijuana. Users identified 2 disadvantages: inconvenience of setup and cleaning and the time it takes to get the device operating for each use. Only 2 individuals combined tobacco in the vaporizer mix, whereas 15 combined tobacco with marijuana when they smoked marijuana. Almost all participants intended to continue using a vaporizer.

Conclusions

Vaporizers seem to have appeal to marijuana users, who perceive them as having harm-reduction and other benefits. Vaporizers are worthy of experimental research evaluating health-related effects of using them.
Average case tractability of approximating ∞-variate functions
Authors: Wasilkowski G.
Published: August 2013

We study function approximation in the average case setting for spaces of

∞
\infty

-variate functions that have a weighted tensor product form and are endowed with a Gaussian measure that also has a weighted tensor product form. Moreover, we assume that the cost of function evaluation depends on the number of active variables and we allow it to be from linear to exponential. We provide a necessary and sufficient condition for the problem to be polynomially tractable and derive the exact value of the tractability exponent. In particular, the approximation problem is polynomially tractable under modest conditions on weights even if the function evaluation cost is exponential in the number of active variables. The problem is weakly tractable even if this cost is doubly exponential. These results hold for algorithms that can use unrestricted linear information. Similar results hold for weighted

L
2

L_2

approximation, a special case of function approximation problems considered in this paper, and algorithms restricted to those that use only function samplings.
Nuclear-localized Asunder regulates cytoplasmic dynein localization via its role in the Integrator complex
Authors: Jodoin Jeanne N. , Sitaram Poojitha , Albrecht Todd R. , May Sarah B. , Shboul Mohammad , Lee Ethan , Reversade Bruno , Wagner Eric J. , Lee Laura A.
Published: August 2013

We previously reported that Asunder (ASUN) is essential for recruitment of dynein motors to the nuclear envelope (NE) and nucleus–centrosome coupling at the onset of cell division in cultured human cells and Drosophila spermatocytes, although the mechanisms underlying this regulation remain unknown. We also identified ASUN as a functional component of Integrator (INT), a multisubunit complex required for 3′-end processing of small nuclear RNAs. We now provide evidence that ASUN acts in the nucleus in concert with other INT components to mediate recruitment of dynein to the NE. Knockdown of other individual INT subunits in HeLa cells recapitulates the loss of perinuclear dynein in ASUN–small interfering RNA cells. Forced localization of ASUN to the cytoplasm via mutation of its nuclear localization sequence blocks its capacity to restore perinuclear dynein in both cultured human cells lacking ASUN and Drosophila asun spermatocytes. In addition, the levels of several INT subunits are reduced at G2/M when dynein is recruited to the NE, suggesting that INT does not directly mediate this step. Taken together, our data support a model in which a nuclear INT complex promotes recruitment of cytoplasmic dynein to the NE, possibly via a mechanism involving RNA processing.
ER exit sites are physical and functional core autophagosome biogenesis components
Authors: Graef Martin , Friedman Jonathan R. , Graham Christopher , Babu Mohan , Nunnari Jodi
Published: August 2013

Autophagy is a central homeostasis and stress response pathway conserved in all eukaryotes. One hallmark of autophagy is the de novo formation of autophagosomes. These double-membrane vesicular structures form around and deliver cargo for degradation by the vacuole/lysosome. Where and how autophagosomes form are outstanding questions. Here we show, using proteomic, cytological, and functional analyses, that autophagosomes are spatially, physically, and functionally linked to endoplasmic reticulum exit sites (ERES), which are specialized regions of the endoplasmic reticulum where COPII transport vesicles are generated. Our data demonstrate that ERES are core autophagosomal biogenesis components whose function is required for the hierarchical assembly of the autophagy machinery immediately downstream of the Atg1 kinase complex at phagophore assembly sites.
Kinannote, a computer program to identify and classify members of the eukaryotic protein kinase superfamily
Authors: Goldberg Jonathan M. , Griggs Allison D. , Smith Janet L. , Haas Brian J. , Wortman Jennifer R. , Zeng Qiandong
Published: August 2013

Motivation: Kinases of the eukaryotic protein kinase superfamily are key regulators of most aspects eukaryotic cellular behavior and have provided several drug targets including kinases dysregulated in cancers. The rapid increase in the number of genomic sequences has created an acute need to identify and classify members of this important class of enzymes efficiently and accurately.

Results: Kinannote produces a draft kinome and comparative analyses for a predicted proteome using a single line command, and it is currently the only tool that automatically classifies protein kinases using the controlled vocabulary of Hanks and Hunter [Hanks and Hunter (1995)]. A hidden Markov model in combination with a position-specific scoring matrix is used by Kinannote to identify kinases, which are subsequently classified using a BLAST comparison with a local version of KinBase, the curated protein kinase dataset from www.kinase.com. Kinannote was tested on the predicted proteomes from four divergent species. The average sensitivity and precision for kinome retrieval from the test species are 94.4 and 96.8%. The ability of Kinannote to classify identified kinases was also evaluated, and the average sensitivity and precision for full classification of conserved kinases are 71.5 and 82.5%, respectively. Kinannote has had a significant impact on eukaryotic genome annotation, providing protein kinase annotations for 36 genomes made public by the Broad Institute in the period spanning 2009 to the present.

Availability: Kinannote is freely available at http://sourceforge.net/projects/kinannote.

Contact:  jmgold@broadinstitute.org

Supplementary information:  Supplementary data are available at Bioinformatics online.
Measuring Unemployment Insurance Generosity
Authors: Pallage Stéphane , Scruggs Lyle , Zimmermann Christian
Published: August 2013

Unemployment insurance policies are multidimensional objects, with variable waiting periods, eligibility duration, benefit levels, and asset tests, making intertemporal or international comparisons very difficult. Furthermore, labor market conditions, such as the likelihood and duration of unemployment, matter when assessing the generosity of different policies. In this article, we develop a new methodology to measure the generosity of unemployment insurance programs with a single metric. We build a first model with all characteristics of the complex unemployment insurance policy. Our model features heterogeneous agents that are liquidity constrained but can self-insure. We then build a second model, similar in all aspects but one: the unemployment insurance policy is one-dimensional (no waiting periods, eligibility limits, or asset tests, but constant benefits). We then determine which level of benefits in this second model makes society indifferent between both policies. We apply this measurement strategy to the unemployment insurance program of the United Kingdom.
Epidemiology of Bacteremia in Young Hospitalized Infants in Vientiane, Laos, 2000–2011
Authors: Anderson Margot , Luangxay Khonesavanh , Sisouk Kongkham , Vorlasan Latdavan , Soumphonphakdy Bandith , Sengmouang Vanmaly , Chansamouth Vilada , Phommasone Koukeo , Van Dyke Russell , Chong Euming , Dance David A.B. , Phetsouvanh Rattanaphone , Newton Paul N.
Published: August 2013

As data about the causes of neonatal sepsis in low-income countries are inadequate, we reviewed the etiology and antibiotic susceptibilities of bacteremia in young infants in Laos. As Staphylococcus aureus is the leading cause of bacteremia in Lao infants, we also examined risk factors for this infection, in particular the local practice of warming mothers during the first weeks postpartum with hot coals under their beds (hot beds). Clinical and laboratory data regarding infants aged 0–60 days evaluated for sepsis within 72 h of admission to Mahosot Hospital in Vientiane, Laos, were reviewed, and 85 of 1438 (5.9%) infants’ blood cultures grew a clinically significant organism. Most common were S. aureus, Escherichia coli and Klebsiella pneumoniae. Whereas no methicillin-resistant S. aureus was found, only 18% of E. coli isolates were susceptible to ampicillin. A history of sleeping on a hot bed with mother was associated with S. aureus bacteremia (odds ratio 4.8; 95% confidence interval 1.2–19.0).
Live Cell Imaging of Cytoplasmic and Nuclear Ca2+ Dynamics in Arabidopsis Roots
Authors: Krebs Melanie , Schumacher Karin
Published: August 2013

Approaches for Ca2+ measurement require data recording with high spatiotemporal resolution. This is achieved by combined usage of locally targeted genetically encoded calcium indicators (GECIs) and confocal laser scanning microscopy (CLSM). This protocol provides instructions for setting up a CLSM-based experiment to measure cytosolic and nuclear Ca2+ dynamics in Arabidopsis lines expressing Yellow Cameleon Ca2+ indicators.
Imaging of Mitochondrial and Nuclear Ca2+ Dynamics in Arabidopsis Roots
Authors: Loro Giovanna , Costa Alex
Published: August 2013

Here we report a method for analyzing mitochondrial Ca2+ dynamics in plant root cells by means of the newly generated cameleon probe 4mt-YC3.6. The use of plants expressing both nuclear- and mitochondrial-targeted cameleon, along with the resolution of confocal laser scanning microscopy (CLSM), allow simultaneous recordings of mitochondrial and nuclear Ca2+ dynamics within the same cell.
Packaging shRNA Retroviruses
Authors: Chang Kenneth , Marran Krista , Valentine Amy , Hannon Gregory J.
Published: August 2013

To silence a mammalian gene by RNAi using an encoded trigger, a short-hairpin RNA (shRNA) is integrated into the host cell genome as a stable transgene. Target cells are infected with viral plasmid containing shRNA inserted into the vector backbone. Before infection, the plasmid is transfected into a packaging cell line, which provides the trans-acting factors necessary for virus production. These include, minimally, capsid proteins and reverse transcriptase, but they can also include other regulatory factors (e.g., tat for some lentiviral vectors). It is critical to choose the correct packaging cell system for the viral backbone to be used. The packaging cell also defines the host range of the virus, depending on the envelope protein that it expresses. Ecotropic viruses are limited to rodent hosts, whereas amphotropic viruses have a broader host range that also includes humans. Often, investigators will express a nonretroviral envelope, such as vesicular stomatitus virus (VSV) glycoprotein, to enhance virus stability and host range and to enable viruses to be concentrated following production. Although viruses carrying shRNAs are packaged almost identically to viruses carrying protein-encoding genes, one twist is worth noting. shRNAs are efficiently cleaved by the host RNAi biogenesis machinery, which can reduce the level of viral genomic RNAs and consequently viral titers. Therefore, titers can be enhanced by cotransfecting the viral plasmid with a small interfering RNA (siRNA) that targets DGCR-8/Pasha, which is a core microRNA (miRNA) biogenesis component. siRNAs against Drosha can also be used.