bluuebunny/crossref_metadata_2025 huggingface dataset:
Nanodiamond dispersions in metallic matrices with different carbon affinity
Authors: Nunes D. , Correia J.B. , Carvalho P.A.
Published: August 2013

Dispersing nanodiamond (nD) particles in metallic matrices can be achieved by ball milling resulting in metal-diamond composite powders. The matrices have been selected considering the whole range of carbon affinity: copper that shows extremely reduced affinity towards carbon phases, potentially compromising the composite interfaces, and nickel and tungsten that are mild and strong carbide formers, respectively, displaying thus intermediate and strong carbon affinities. For the latter matrices, dispersing carbon phases represent a challenge due to carbide conversion.

The materials produced are designated as Cu-10nD, Ni-10nD and W-20nD (where 10 and 20 indicate the atomic fraction of nD). Close monitoring of the milling conditions enabled to homogeneously disperse the carbon phases and obtain nanostructured matrices (Figures 1 (a-c)), as well as to minimize milling media contamination and carbide formation, especially in the case of the W-based composite. Apparent interfacial bonding could be inferred the from transmission electron microscopy (TEM) images.

The metallic matrices have been subsequently dissolved to allow for a detailed analysis of nanodiamond. Electron diffraction demonstrated that its crystalline structure was preserved during milling (Figure 2). Microhardness measurements revealed remarkable strength enhancements of the nanostructured composites over that of pure metals of comparable grain sizes (Table 1). The strengthening mechanisms that justify the hardness increments in Cu-10nD and Ni-10nD include second-phase reinforcement (due to the potential load bearing ability of diamond), as well as Orowan and solid solution strengthening. The hardening effect observed in the W-20nD composite over that of pure milled tungsten is probably related to the nanodiamond reinforcement, nevertheless the influence of a fine dispersion of carbides cannot be ruled out.

This work has been performed under the Contract of Association between EURATOM and Instituto Superior Tecnico. Financial support was also received from the Fundação para a Ciência Tecnologia (FCT) grants with references PTDC/CTM/100163/2008, Pest-OE/SADG/LA0010/2011 and PEST-OE/CTM-UI0084/2011.
Editorial
Authors: Alves de Matos AP
Published: August 2013

SPMicros was born in the year 1966 and since then the Society has promoted 46 annual Congresses. These have been long recognized as a nursery for young scientists with a special interest in microscopy. The meetings of the Society, fostered by high level scientists like David Ferreira and Teixeira da Silva, to mention only the ones that have left us this year, were once marked by a exigent standard of quality that left a lasting mark in all of us.
Transmission Electron Microscopy Characterization of Thermomechanically Treated Al3Ti–(8, 10, 15)% Cr Intermetallics
Authors: Jang Ok Jun , Yang Cheol-Woong , Lee Dong Bok
Published: August 2013

The ordered L12-type Al3Ti–(8, 10, 15)% Cr intermetallic compounds, namely, Al67Ti25Cr8, Al66Ti24Cr10, and Al59Ti26Cr15, were prepared by induction melting followed by thermomechanical treatment. Their microstructure, compositional variation, and crystal structure were characterized using X-ray diffraction, optical microscopy, and scanning and transmission electron microscopy equipped with energy-dispersive spectroscopy. The Al67Ti25Cr8 alloy consisted of the L12-Al3Ti matrix and precipitates of α2-Ti3Al, D022-Al3Ti, and γ-TiAl. The Al66Ti24Cr10 and Al59Ti26Cr15 alloys consisted of the L12-Al3Ti matrix and grains of α-TiAl and β-Cr.
-ALGEBRAS ASSOCIATED WITH LAMBDA-SYNCHRONIZING SUBSHIFTS AND FLOW EQUIVALENCE
Authors: MATSUMOTO KENGO
Published: August 2013

The class of$\lambda $-synchronizing subshifts generalizes the class of irreducible sofic shifts. A$\lambda $-synchronizing subshift can be presented by a certain$\lambda $-graph system, called the$\lambda $-synchronizing$\lambda $-graph system. The$\lambda $-synchronizing$\lambda $-graph system of a$\lambda $-synchronizing subshift can be regarded as an analogue of the Fischer cover of an irreducible sofic shift. We will study algebraic structure of the${C}^{\ast } $-algebra associated with a$\lambda $-synchronizing$\lambda $-graph system and prove that the stable isomorphism class of the${C}^{\ast } $-algebra with its Cartan subalgebra is invariant under flow equivalence of$\lambda $-synchronizing subshifts.
MC4R rs489693: a clinical risk factor for second generation antipsychotic-related weight gain?
Authors: Czerwensky Fabian , Leucht Stefan , Steimer Werner
Published: August 2013

Weight gain is a therapy limiting and very frequent adverse effect of many second-generation antipsychotic (SGA) drugs. The human melanocortin four receptor (MC4R) is a very promising candidate gene possibly influencing SGA-related weight gain. The rs489693 polymorphism near the MC4R gene was associated with SGA-related weight gain in a genome-wide association study. We tried to replicate these results in our independent naturalistic study population. From 341 Caucasian inpatients receiving at least one SGA drug (olanzapine, clozapine, risperidone, paliperidone, quetiapine or amisulpride), carriers homozygous for the rs489693 A-allele (n = 35) showed a 2.2 times higher weight increase (+2.2 kg) than carriers of the CC-genotype (+1 kg) after 4 wk of treatment (analysis of covariance, p = 0.039). We revealed an even stronger effect in a subpopulation without weight gain inducing co-medication (factor 3.1, +2.8 kg, p = 0.044, (n = 16 of 169)) and in first episode patients (factor 2.7, +2.7 kg, p = 0.017, (n = 13 of 86)). Our results confirm the rs489693 A-allele as a possible risk factor for SGA-related weight gain.
Preliminary study of themes of meaning and psychosocial service use among informal cancer caregivers
Authors: Applebaum Allison J. , Farran Carol J. , Marziliano Allison M. , Pasternak Anna R. , Breitbart William
Published: August 2013

Objective:

The burden experienced by informal caregivers (ICs) of patients with advanced cancer is well documented. ICs are at risk for anxiety and depression, as well as existential concerns that arise when a loved one is facing a terminal illness. Few psychosocial interventions focus on existential concerns of ICs. However, a growing body of literature indicates that finding meaning in the experience of being an IC for a person with cancer has the potential to buffer against burden. The purpose of this study was to collect preliminary descriptive data regarding caregiver burden, meaning, and psychosocial service use to inform the adaptation of a meaning-centered intervention for ICs.

Method:

Twenty-five caregivers and 32 patients completed brief, anonymous questionnaires that asked about their role as a caregiver or their perception of their loved one as a caregiver, caregiver burden, and psychosocial service use.

Results:

Caregivers and patients identified anxiety and depression as top correlates of burden experienced by caregivers, whereas guilt, issues with role/sense of identity, and self-care were additional areas of concern. The majority of caregivers were not receiving psychosocial services, although they almost unanimously reported desiring services. A greater proportion of patients than caregivers believed that an intervention designed to enhance meaning would ameliorate burden, but, nevertheless, close to three quarters of caregivers reported interest in participating in such an intervention.

Significance of results:

These study findings provide further support for, at a minimum, engaging ICs of persons with advanced cancer in interventions that address existential issues, mental health, self-care, and service use. Such interventions are likely to improve the quality of life of both patients with cancer and their ICs.
RNA sensing: the more RIG‐I the merrier?
Authors: Rehwinkel Jan
Published: August 2013

RIG‐I is an RNA helicase with important roles in immunity to RNA viruses. Two studies in this issue of EMBO reports provide new insights into the role of ATP hydrolysis by the helicase domain and RIG‐I oligomerization.
Adenosine A2A Receptor Deficiency Alleviates Blast-Induced Cognitive Dysfunction
Authors: Ning Ya-Lei , Yang Nan , Chen Xing , Xiong Ren-Ping , Zhang Xiu-Zhu , Li Ping , Zhao Yan , Chen Xing-Yun , Liu Ping , Peng Yan , Wang Zheng-Guo , Chen Jiang-Fan , Zhou Yuan-Guo
Published: August 2013

Traumatic brain injury (TBI), particularly explosive blast-induced TBI (bTBI), has become the most prevalent injury among military personnel. The disruption of cognitive function is one of the most serious consequences of bTBI because its long-lasting effects prevent survivors fulfilling their active duty and resuming normal civilian life. However, the mechanisms are poorly understood and there is no treatment available. This study investigated the effects of adenosine A2A receptor (A2AR) on bTBI-induced cognitive deficit, and explored the underlying mechanisms. After being subjected to moderate whole-body blast injury, mice lacking the A2AR (A2AR knockout (KO)) showed less severity and shorter duration of impaired spatial reference memory and working memory than wild-type mice did. In addition, bTBI-induced cortical and hippocampal lesions, as well as proinflammatory cytokine expression, glutamate release, edema, cell loss, and gliosis in both early and prolonged phases of the injury, were significantly attenuated in A2AR KO mice. The results suggest that early injury and chronic neuropathological damages are important mechanisms of bTBI-induced cognitive impairment, and that the impairment can be attenuated by preventing A2AR activation. These findings suggest that A2AR antagonism is a potential therapeutic strategy for mild-to-moderate bTBI and consequent cognitive impairment.
Reference Region Automatic Extraction in Dynamic [11C]PIB
Authors: Ikoma Yoko , Edison Paul , Ramlackhansingh Anil , Brooks David J , Turkheimer Federico E
Published: August 2013

The positron emission tomography (PET) radiotracer [11C]Pittsburgh Compound B (PIB) is a marker of amyloid plaque deposition in brain, and binding potential is usually quantified using the cerebellum as a reference where the specific binding is negligible. The use of the cerebellum as a reference, however, has been questioned by the reported cerebellar [11C]PIB retention in familial Alzheimer's disease (AD) subjects. In this work, we developed a supervised clustering procedure for the automatic extraction of a reference region in [11C]PIB studies. Supervised clustering models each gray matter voxel as the linear combination of three predefined kinetic classes, normal and lesion gray matter, and blood pool, and extract reference voxels in which the contribution of the normal gray matter class is high. In the validation with idiopathic AD subjects, supervised clustering extracted reference voxels mostly in the cerebellum that indicated little specific [11C]PIB binding, and total distribution volumes of the extracted region were lower than those of the cerebellum. Next, the methodology was applied to the familial AD cohort where the cerebellar amyloid load had been demonstrated previously, resulting in higher binding potential compared with that obtained with the cerebellar reference. The supervised clustering method is a useful tool for the accurate quantification of [11C]PIB studies.
Tracer Kinetic Modeling of [11C]AFM, a New PET Imaging Agent for the Serotonin Transporter
Authors: Naganawa Mika , Nabulsi Nabeel , Planeta Beata , Gallezot Jean-Dominique , Lin Shu-Fei , Najafzadeh Soheila , Williams Wendol , Ropchan Jim , Labaree David , Neumeister Alexander , Huang Yiyun , Carson Richard E
Published: August 2013

[11C]AFM, or [11C]2-[2-(dimethylaminomethyl)phenylthio]-5-fluoromethylphenylamine, is a new positron emission tomography (PET) radioligand with high affinity and selectivity for the serotonin transporter (SERT). The purpose of this study was to determine the most appropriate kinetic model to quantify [11C]AFM binding in the healthy human brain. Positron emission tomography data and arterial input functions were acquired from 10 subjects. Compartmental modeling and the multilinear analysis-1(MA1) method were tested using the arterial input functions. The one-tissue model showed a lack of fit in low-binding regions, and the two-tissue model failed to estimate parameters reliably. Regional time–activity curves were well described by MA1. The rank order of [11C]AFM binding potential ( BPND) matched well with the known regional SERT densities. For routine use of [11C]AFM, several noninvasive methods for quantification of regional binding were evaluated, including simplified reference tissue models (SRTM and SRTM2), and multilinear reference tissue models (MRTM and MRTM2). The best methods for region of interest (ROI) analysis were MA1, MRTM2, and SRTM2, with fixed population kinetic values ( k′2 or b′) for the reference methods. The MA1 and MRTM2 methods were best for parametric imaging. These results showed that [11C]AFM is a suitable PET radioligand to image and quantify SERT in humans.
The synthesis and characterization of supramolecular elastomers based on linear carboxyl-terminated polydimethylsiloxane oligomers
Authors: Yang Lin , Lin Yaling , Wang Lianshi , Zhang Anqiang
Published: August 2013

Supramolecular elastomers obtained through a two-step reaction of linear carboxyl-terminated polydimethylsiloxane oligomers (PDMS–COOH2) with diethylenetriamine (DETA) and urea show reasonable hysteresis and acceptable self-healing properties.
A novel fluorescence assay and catalytic properties of Crh1 and Crh2 yeast cell wall transglycosylases
Authors: Mazáň Marian , Blanco Noelia , Kováčová Kristína , Firáková Zuzana , Řehulka Pavel , Farkaš Vladimír , Arroyo Javier
Published: August 2013

The mechanical properties of fungal cell walls are largely determined by composition and mutual cross-linking of their macromolecular components. Previous work showed that the Crh proteins are required for the formation of cross-links between chitin and glucan at the Saccharomyces cerevisiae cell wall. In the present study, the proteins encoded by CRH1 and CRH2 were heterologously expressed in Pichia pastoris and a sensitive fluorescence in vitro soluble assay was devised for determination of their transglycosylating activities. Both proteins act as chitin transglycosylases; they use soluble chitin derivatives, such as carboxymethyl chitin, glycol-chitin and/or N-acetyl chito-oligosaccharides of DP (degree of polymerization)≥5 as the oligoglycosyl donors, and oligosaccharides derived from chitin, β-(1,3)-glucan (laminarin) and β-(1,6)-glucan (pustulan), fluorescently labelled with sulforhodamine or FITC as acceptors. The minimal number of intact hexopyranose units required by Crh1 and/or Crh2 in the molecule of the acceptor oligosaccharide was two and the effectivity of the acceptor increased with the increasing length of its oligosaccharide chain. Products of the transglycosylation reactions were hybrid molecules composed of the acceptor and portions of carboxymethyl chitin attached to its non-reducing end. Both proteins exhibited a weak chitinolytic activity in different assays whereby the ratio of endo- compared with exo-chitinase activity was approximately 4-fold higher in Crh1 than in Crh2. The pH optimum of both enzymes was 3.5 and the optimum temperature was 37°C. The results obtained in vitro with different fluorescently labelled oligosaccharides as artificial chitin acceptors corroborated well with those observed in vivo.
Adaptive relaying scheme for cognitive radio networks
Authors: Jaafar Wael , Ajib Wessam , Haccoun David
Published: August 2013

Cognitive radio (CR) systems allow unlicensed secondary users to transmit on the licensed frequency bands without degrading the licensed primary transmissions. Combining CR with other emerging transmission techniques, such as user cooperation may have many benefits on both the primary and secondary transmissions. In this study, the authors propose and investigate an adaptive relay‐based cooperation scheme for CR networks that improves the secondary outage performance, while respecting a primary outage probability threshold. The proposed adaptive scheme considers one multi‐antenna relay node that, by selecting the antenna(s) to use, can assist either the primary, the secondary or both transmissions simultaneously. Expressions of the conditional primary outage probability for Rayleigh fading channels are derived and used to investigate the associated power allocation problem. Simulation results show that both primary and secondary outage probabilities of the proposed scheme are significantly improved and outperform non‐cooperative and cooperative schemes given in the literature.
Efficient swarm intelligent algorithm for power control game in cognitive radio networks
Authors: Kuo Yonghong , Yang Jianghong , Chen Jian
Published: August 2013

Cognitive radio networks (CRNs) are applied to solve spectrum scarcity. In this study, the authors propose an efficient power control game to improve its performance based on outage probability of primary user in a spectrum‐underlay CRN. The interference threshold deduced from outage probability and normalised signal to interference plus noise ratio are used to develop a novel non‐linear pricing function, which is a key element of obtaining Pareto improvement in non‐cooperative power control game. In addition, an efficient swarm intelligent algorithm originated from eco‐group activities is designed in detail to accelerate the convergence speed and improve the energy‐efficiency. Theoretical analysis and simulation results are presented to prove the effectiveness and superiority of the proposed power control game.
Quantitative analysis of the effects of iododeoxyuridine and ionising radiation treatment on the cell cycle dynamics of DNA mismatch repair deficient human colorectal cancer cells
Authors: Gurkan‐Cavusoglu Evren , Schupp Jane E. , Kinsella Timothy J. , Loparo Kenneth A.
Published: August 2013

DNA mismatch repair (MMR) is involved in processing DNA damage following treatment with ionising radiation (IR) and various classes of chemotherapy drugs including iododeoxyuridine (IUdR), a known radiosensitiser. In this study, the authors have developed asynchronous probabilistic cell cycle models to assess the isolated effects of IUdR and IR and the combined effects of IUdR + IR treatments on MMR damage processing. The authors used both synchronous and asynchronous MMR‐proficient/MMR‐deficient cell populations and followed treated cells for up to two cell cycle times. They have observed and quantified differential cell cycle responses to MMR damage processing following IR and IUdR + IR treatments, principally in the duration of both G 1 and G 2/M cell cycle phases. The models presented in this work form the foundation for the development of an approach to maximise the therapeutic index for IR and IUdR + IR treatments in MMR‐deficient (damage tolerant) cancers.
Stress magnetization model for magnetostriction in multiferroic composite
Authors: Gualdi A. J. , Zabotto F. L. , Garcia D. , de Oliveira A. J. A.
Published: August 2013

An alternative to obtain multiferroic materials is the production of composite materials that combine ferroelectric and magnetic materials. In particular, the use of magnetostrictive materials as ferromagnetic phase in composites is very important because the mechanical stress applied in ferroelectric phase induces the appearance of magnetoelectric effect. In this work, we have proposed a generalized model for the magnetostriction dependence with the magnetization of the 0-3 type composite magnetoelectric materials. Including both piezomagnetic and stress dependence in the magnetostriction, a relevant improvement was reached as compared to the ordinary square magnetization model. Based on the Gibbs free energy expansion, the magnetostriction behavior of the composite (1−x)Pb(Mg1/3Nb2/3)−xPbTiO3/CoFe2O4 at 300 K and 5 K is described. Furthermore, using the piezomagnetic correction, the magnetostriction data for the pure CoFe2O4 is fitted showing that this ferrite presents a relevant piezomagnetic effect.
Polarization as a field variable from molecular dynamics simulations
Authors: Mandadapu Kranthi K. , Templeton Jeremy A. , Lee Jonathan W.
Published: August 2013

A theoretical and computational framework for systematically calculating the macroscopic polarization density as a field variable from molecular dynamics simulations is presented. This is done by extending the celebrated Irving and Kirkwood [J. Chem. Phys. 18, 817 (1950)10.1063/1.1747782] procedure, which expresses macroscopic stresses and heat fluxes in terms of the atomic variables, to the case of electrostatics. The resultant macroscopic polarization density contains molecular dipole, quadrupole, and higher-order moments, and can be calculated to a desired accuracy depending on the degree of the coarse-graining function used to connect the molecular and continuum scales. The theoretical and computational framework is verified by recovering the dielectric constant of bulk water. Finally, the theory is applied to calculate the spatial variation of the polarization vector in the electrical double layer of a 1:1 electrolyte solution. Here, an intermediate asymptotic length scale is revealed in a specific region, which validates the application of mean field Poisson-Boltzmann theory to describe this region. Also, using the existence of this asymptotic length scale, the lengths of the diffuse and condensed/Stern layers are identified accurately, demonstrating that this framework may be used to characterize electrical double layers over a wide range of concentrations of solutions and surface charges.
The propagation of detonation waves in non-ideal condensed-phase explosives confined by high sound-speed materials
Authors: Schoch Stefan , Nikiforakis Nikolaos , Lee Bok Jik
Published: August 2013

Highly non-ideal condensed-phase explosives used by the mining industry have a strong detonation velocity dependence on the charge dimension. Detonation velocities can be as low as one third of the theoretically calculated ideal detonation velocity in charge radii close to the failure radius. Under these detonation conditions the flow in the confiner can become subsonic, a flow condition under which classical shock-polar analysis is not applicable. This restriction prohibits the use of popular engineering models like detonation shock dynamics and Wood-Kirkwood type models under these confinement conditions. In addition, it has been found in the literature that subsonic flow in the confiner will increase the influence of the confining material on the detonation performance. In this work, we use a multi-phase model coupled to an elastic-plastic model (for the representation of a confiner) to explore the interaction of detonations under these confiner conditions. An ammonium nitrate based mining emulsion is investigated in aluminium and steel confinement of finite and infinite thickness representing the confiner as either a fluid or an elastic-plastic material. It is found that the presence of elastic waves is negligible close to ideal detonation conditions, but is important close to the failure radius and in detonation conditions with subsonic flow in the confiner. High sound-speed confiners support the detonation through energy transport ahead of the detonation front if desensitisation effects are negligible. The detonation front profiles are found to remain convex even in the most non-ideal detonation conditions, and the detonation front curvature only becomes concave in a localised region close to the confiner edge.
Development of frequency modulation reflectometer for Korea Superconducting Tokamak Advanced Research tokamak
Authors: Seo Seong-Heon , Park Jinhyung , Wi H. M. , Lee W. R. , Kim H. S. , Lee T. G. , Kim Y. S. , Kang Jin-Seob , Bog M. G. , Yokota Y. , Mase A.
Published: August 2013

Frequency modulation reflectometer has been developed to measure the plasma density profile of the Korea Superconducting Tokamak Advanced Research tokamak. Three reflectometers are operating in extraordinary polarization mode in the frequency range of Q band (33.6–54 GHz), V band (48–72 GHz), and W band (72–108 GHz) to measure the density up to 7 × 1019 m−3 when the toroidal magnetic field is 2 T on axis. The antenna is installed inside of the vacuum vessel. A new vacuum window is developed by using 50 μm thick mica film and 0.1 mm thick gold gasket. The filter bank of low pass filter, notch filter, and Faraday isolator is used to reject the electron cyclotron heating high power at attenuation of 60 dB. The full frequency band is swept in 20 μs. The mixer output is directly digitized with sampling rate of 100 MSamples/s. The phase is obtained by using wavelet transform. The whole hardware and software system is described in detail and the measured density profile is presented as a result.
A novel laboratory set-up for investigating surface and interface reactions during short term annealing cycles at high temperatures
Authors: Auinger M. , Vogel D. , Vogel A. , Spiegel M. , Rohwerder M.
Published: August 2013

High temperature oxidation is an important research discipline that covers many topics in steel manufacture and modern energy research. To account for the need of adjusting accurate processing conditions, recent developments of the high temperature laboratory setup at the Max-Planck-Institut für Eisenforschung GmbH will be presented. The experimental assembly has been optimized to investigate surface and interface reactions at elevated temperatures in low oxygen activity gases, covering a large field of experimental possibilities. Many efforts have been taken to enable an accurate control and in situ monitoring of process conditions such as gas flow, gas composition, impurity content, and mass change of the sample.
On a different approach toward low-frequency dielectric spectroscopy measurements of conductive liquids
Authors: Hunter Woodward W. H. , Pasztor Andrew J. , Chatterjee Tirtha , Nakatani Alan I.
Published: August 2013

Driven by recent interest in the low-frequency Debye-like relaxations in hydrogen bonding liquids, here we present an alternative method for measuring such relaxations without the detrimental effects of ionic conductivity or electrode polarization. Glycerol was chosen as a molecule of interest, and a fit for the α-transition using the Vogel-Fulcher-Tammann equation was found to be τ = 2.31 × 10−14 exp(2110 K/[T–135 K]). This method is easily adaptable by most laboratories with existing dielectric spectrometers, and could prove useful in the accurate measurement of relaxations in conductive media at low frequencies. A brief summary of comparable techniques is also presented.
Structural evolution of Ga-Ge-Te glasses by combined EXAFS and XPS analysis
Authors: Golovchak R. , Calvez L. , Bureau B. , Jain H.
Published: August 2013

The structural evolution of GaxGeyTe100−x−y glasses in the vicinity of GeTe4-GaTe3 pseudo-binary tie-line is determined with high-resolution X-ray photoelectron (XPS) and extended X-ray absorption fine structure (EXAFS) spectroscopies. The analysis of XPS data is complicated by similar electronegativity values for the constituent chemical elements, but then the interpretation is facilitated by information from complementary EXAFS analysis of the structure around each element independently. The results show 4/4/2 coordination for Ga/Ge/Te atoms and absence of Ga(Ge)-Ge(Ga) bonds or extended Te clusters in significant concentrations within the whole range of studied composition. The observed structural features correlate well with the measured basic physical properties of Ga-containing germanium telluride glasses.
Rapid estimation of hydration thermodynamics of macromolecular regions
Authors: Raman E. Prabhu , MacKerell Alexander D.
Published: August 2013

This work describes a novel protocol to efficiently calculate the local free energy of hydration of specific regions in macromolecules. The method employs Monte Carlo simulations in the grand canonical ensemble to generate water configurations in a selected spherical region in the macromolecule. Excess energy and entropy of hydration are calculated by analyzing the water configurational distributions following the recently published grid inhomogeneous solvation theory method [C. N. Nguyen, T. K. Young, and M. K. Gilson, J. Chem. Phys. 137, 044101 (2012)]10.1063/1.4733951. Our method involves the approximations of treating the macromolecule and distant solvent as rigid and performing calculations on multiple such conformations to account for conformational diversity. These approximations are tested against water configurations obtained from a molecular dynamics simulation. The method is validated by predicting the number and location of water molecules in 5 pockets in the protein Interleukin-1β for which experimental water occupancy data are available. Free energy values are validated against decoupling free energy perturbation calculations. The results indicate that the approximations used in the method enable efficient prediction of free energies of water displacement.
Depth-dependent temperature effects on thermoluminescence in multilayers
Authors: Kim Sangho S. , Armstrong Philip R. , Mah Merlin L. , Talghader Joseph J.
Published: August 2013

It is well known that thermal gradients penetrating deep into a material can preserve a memory of the temperature history of the surface. To date, this concept has been largely applied in the earth sciences, but there are many applications where a memory of rapid thermal events would be useful. For example, multiple layers of thermoluminescent films could serve as temperature sensors that indicate temperature versus depth in a microfabricated structure. As an advance toward this goal, this paper examines the effect of nonuniform temperature profiles on the thermoluminescence of heterogeneous multilayers. A Nd:YAG laser is used to create a known thermal event and apply pulses of heat energy of varying duration to a metalized thermoluminescent multilayer composed of LiF:Mg,Ti and CaF2:Dy. The thermoluminescence of the system is measured before and after the applied laser pulse. To model the process, a finite-difference time-domain method is used to calculate the dynamic heat transfer, and the temperature distribution is plugged into a first order kinetics model of the thermoluminescence of each film to get a final luminescent intensity. A thermal contact conductance between the critical layers is also introduced. Dynamic temperatures in durations of hundreds of milliseconds are resolved with the technique, and simulation curves match experimental measurements to within 6% at 250 ms.
Hybrid heterostructures based on aromatic polyimide and semiconductor CdSe quantum dots for photovoltaic applications
Authors: Dayneko Sergey , Tameev Alexey , Tedoradze Marine , Martynov Igor , Artemyev Mikhail , Nabiev Igor , Chistyakov Alexander
Published: August 2013

A nanohybrid photoactive material based on aromatic polyimide (PI) doped with CdSe quantum dots (QDs) has been developed to be used in photovoltaic solar cells. The solar cell is based on a heterostructure of an ITO electrode covered with a layer of Cu–phthalocyanine and a layer of a PI–QD composite. The photovoltaic properties of the CuPc/PI:CdSe hybrid heterostructure at various QD concentrations in the PI matrix have been studied. Luminescent and transmission electron microscopy analyses have shown that the optimal QD mass concentration is 60%. The efficiency of the solar cell based on optimized PI:CdSe structures approaches those for the structures based on conventional MEH-PPV organic semiconductor. Moreover, the photovoltaic characteristics of the solar cell remain stable in the air for a long time (120 h). This is expected to considerably simplify the technology of manufacturing these hybrid solar cells. The mechanisms of the excitation and charge transfer from QDs to the organic semiconductors and influence of QDs on the efficiency of solar energy conversion to electricity are discussed.
Electronic and structural properties of femtosecond laser sulfur hyperdoped silicon pn-junctions
Authors: Saring Philipp , Lena Baumann Anna , Schlieper-Ludewig Bettina , Kontermann Stefan , Schade Wolfgang , Seibt Michael
Published: August 2013

The structural properties of femtosecond laser sulfur hyperdoped silicon pn-junctions are correlated to electronic transport characteristics at the interface. The depth of the planar space charge region obtained from cross-sectional electron beam induced current analysis is in good agreement with the sulfur concentration depth profile, derived from secondary ion mass spectroscopy. EBIC signals from the crest regions of the laser structured surface reveal increased recombination activity. Using transmission electron microscopy, we show that such recombination is related to dislocations, which are most probably highly decorated with sulfur.
Stability, resolution, and ultra-low wear amplitude modulation atomic force microscopy of DNA: Small amplitude small set-point imaging
Authors: Santos Sergio , Barcons Victor , Christenson Hugo K. , Billingsley Daniel J. , Bonass William A. , Font Josep , Thomson Neil H.
Published: August 2013

A way to operate fundamental mode amplitude modulation atomic force microscopy is introduced which optimizes stability and resolution for a given tip size and shows negligible tip wear over extended time periods (∼24 h). In small amplitude small set-point (SASS) imaging, the cantilever oscillates with sub-nanometer amplitudes in the proximity of the sample, without the requirement of using large drive forces, as the dynamics smoothly lead the tip to the surface through the water layer. SASS is demonstrated on single molecules of double-stranded DNA in ambient conditions where sharp silicon tips (R ∼ 2–5 nm) can resolve the right-handed double helix.
Epitaxial ferroelectric BiFeO3 thin films for unassisted photocatalytic water splitting
Authors: Ji Wei , Yao Kui , Lim Yee-Fun , Liang Yung C. , Suwardi Ady
Published: August 2013

Considering energy band alignment and polarization effect, ferroelectric BiFeO3 thin films are proposed as the photoanode in a monolithic cell to achieve unassisted photocatalytic water splitting. Significant anodic photocurrent was observed in our epitaxial ferroelectric BiFeO3 films prepared from sputter deposition. Both negative polarization charges and thinner films were found to promote the anodic photocatalytic reaction. Ultraviolet photoelectron spectroscopy proved that the conduction and valence band edges of BiFeO3 straddle the water redox levels. Theoretical analyses show that the large switchable polarization can modify the surface properties to promote the hydrogen and oxygen evolutions on the surfaces with positive and negative polarization charges, respectively.
Self-excited coupled cantilevers for mass sensing in viscous measurement environments
Authors: Yabuno Hiroshi , Seo Yasuhiro , Kuroda Masaharu
Published: August 2013

The eigenstate shift in two nearly identical and weakly coupled cantilevers provides a means to realize much higher-sensitivity mass detection compared with the eigenfrequency shift approach. We propose using self-excited oscillations for eigenstate detection without using frequency response or resonance curve normally used in conventional methods. Mass sensing thus becomes possible even in high-viscosity environments, where the peak of the frequency response curve is ambiguous or does not exist. The feedback control method is theoretically clarified to produce self-excited oscillation and the validity of the proposed method is investigated experimentally using macroscale coupled cantilevers.
Ferroelectric domain evolution with temperature in BaTiO3 film on (001) SrTiO3 substrate
Authors: Yuan Guoliang , Chen Jiangpeng , Xia Hui , Liu Junming , Yin Jiang , Liu Zhiguo
Published: August 2013

The evolution of ferroelectric domains in BaTiO3 film on (001) SrTiO3 substrate is studied at 20–120 °C. The dominant domains orient in (001) plane due to strong internal strain when BaTiO3 island grains are embedded in the film, most of which is of layer-by-layer growth. These domains are commonly larger than grains at 20 °C; however, they are close to grain size at 60–80 °C, which largely enhances the coercive field. The in-plane domains are very stable at 20 °C; however, they can transform to out-of-plane domains at 40–80 °C under electric field, which is likely the cause of enhanced piezoelectric response.
Quantitative Detection with Surface Enhanced Raman Scattering (SERS) Using Self-Assembled Gold Nanoparticle Cluster Arrays
Authors: Dinda Sanghamitra , Yap Fung Ling , Suresh Vignesh , Gupta Raju Kumar , Das Debajyoti , Krishnamoorthy Sivashankar
Published: August 2013

We analysed sensitivity of high-density arrays of self-assembled gold nanoparticle clusters towards trace analyte detection and quantitative determination by surface enhanced Raman spectroscopy (SERS) employing an aromatic thiol as probe molecule. Periodic nanoscale arrays of gold nanoparticle clusters consisting of an average of 18 nanoparticles per cluster, and exhibiting mean inter-particle and inter-cluster separations below 10 nm were prepared using electrostatic self-assembly on block copolymer templates. The concentration dependent scaling of SERS intensities and the lowest detection limits on the cluster arrays on silicon substrate was probed using 1-naphthalenethiol (NT) as test molecule. The substrates show a detection limit of 10 nM along with high sensitivity to changes in NT concentration, which we attribute to high density of hot-spots uniformly organised across the surface. The capability for facile realisation of such arrays without a clean room environment or expensive tools makes the approach suitable for adoption for economic and high-performing SERS sensors.
The Effect of Solvent on the Morphology of Indium Oxide Deposited by Aerosol-assisted Chemical Vapour Deposition
Authors: Hassan Iman A. , Ratnasothy Arnold , Bhachu Davinder S. , Sathasivam Sanjayan , Carmalt Claire J.
Published: August 2013

Aerosol-assisted chemical vapour deposition (AACVD) reactions of InMe3 and a mono-functional or donor-functional alcohol have been investigated and the resulting film morphology studied using scanning electron microscopy. AACVD of InMe3 and 6 equivalents of the donor-functionalized alcohol HOCH2CH2NMe2 in toluene resulted in the deposition of transparent indium oxide films, with a slight brown tinge, at 450°C. In contrast, AACVD of InMe3 and 6 equivalents of MeOH in toluene resulted in no film growth. However, use of methanol as both the solvent and oxygen source via AACVD of InMe3 in MeOH at a range of temperatures (350–500°C) afforded crystalline transparent indium oxide films. Similarly, AACVD of InMe3 and 6 equivalents of HOCH2CH2NMe2 in MeOH resulted in transparent indium oxide films with better substrate coverage. The indium oxide films were analyzed by a range of techniques including scanning electron microscopy, glancing-angle X-ray powder diffraction, UV-visible spectroscopy, and wavelength dispersive analysis of X-rays, which confirmed the formation of cubic In2O3 with band-gaps in the range 3.51–3.60 eV. Scanning electron microscopy showed a variation in film morphology and indicated that both temperature and the use of methanol influenced the resulting microstructure. Sheet resistance and Hall effect measurements indicate that the films deposited at 450°C are suitable candidates for transparent conducting oxide materials.
Fragment-based Drug Discovery: the Shape of Things to Come
Authors: Drysdale Martin J.
Published: August 2013

Fragment-Based Drug Discovery (FBDD) is here to stay. Validated as a technology with the delivery of Zelboraf (Vemurafenib) for the treatment of mutant B-RafV600E melanoma, it has become embedded within the pharmaceutical and biotechnology industries. FBDD has delivered clinical development candidates for a broad range of targets including some of the most challenging cases such as β-secretase (BACE1) and protein–protein interactions. But the best is surely still to come.
Past and present distribution of Dasycercus: toward a better understanding of the identity of specimens in cave deposits and the conservation status of the currently recognised species D. blythi and D. cristicauda (Marsupialia : Dasyuridae)
Authors: Woolley P. A. , Haslem A. , Westerman M.
Published: August 2013

Maps of the distribution of the two currently recognised species of Dasycercus, D. blythi and D. cristicauda have been prepared following correct identification based on tail morphology of specimens in the modern collections of all Australian museums. Localities in which the remains of Dasycercus have been found in cave deposits have also been mapped and an attempt made to determine the specific identity of some of these specimens. Following examination of larger samples of each species, differences in the premolar dentition were found to no longer be diagnostic. Most cave specimens could not be assigned to species on the basis of some dental measurements. DNA sequences could provide a means for establishing the identity of the cave specimens. Correct identification of specimens, together with knowledge of the search effort underlying the known distribution and persistence of the species in localities over their ranges, is essential for assessment of their conservation status.
Unique insights into the intestinal absorption, transit, and subsequent biodistribution of polymer-derived microspheres
Authors: Reineke Joshua J. , Cho Daniel Y. , Dingle Yu-Ting , Morello A. Peter , Jacob Jules , Thanos Christopher G. , Mathiowitz Edith
Published: August 2013

Polymeric microspheres (MSs) have received attention for their potential to improve the delivery of drugs with poor oral bioavailability. Although MSs can be absorbed into the absorptive epithelium of the small intestine, little is known about the physiologic mechanisms that are responsible for their cellular trafficking. In these experiments, nonbiodegradable polystyrene MSs (diameter range: 500 nm to 5 µm) were delivered locally to the jejunum or ileum or by oral administration to young male rats. Following administration, MSs were taken up rapidly (≤5 min) by the small intestine and were detected by transmission electron microscopy and confocal laser scanning microscopy. Gel permeation chromatography confirmed that polymer was present in all tissue samples, including the brain. These results confirm that MSs (diameter range: 500 nm to 5 µm) were absorbed by the small intestine and distributed throughout the rat. After delivering MSs to the jejunum or ileum, high concentrations of polystyrene were detected in the liver, kidneys, and lungs. The pharmacologic inhibitors chlorpromazine, phorbol 12-myristate 13-acetate, and cytochalasin D caused a reduction in the total number of MSs absorbed in the jejunum and ileum, demonstrating that nonphagocytic processes (including endocytosis) direct the uptake of MSs in the small intestine. These results challenge the convention that phagocytic cells such as the microfold cells solely facilitate MS absorption in the small intestine.
Argumentation in hypertext
Authors: Degano Chiara
Published: August 2013

This paper investigates variation in argumentative discourse as a consequence of the passage from traditional linear texts to hypertext, focusing in particular on NGOs’ campaigning on the web. The analysis, which combines linguistic and argumentation theory perspectives (drawing for the latter on the pragmadialectical approach), addresses issues connected with the loss of linearity determined by hypertexts, with special regard for its impact on textual coherence, and the consequential loss of the writer’s control on the order of arguments (dispositio).
Effects of Social Networks on Finding an Apprenticeship in the German Vocational Training System
Authors: Roth Tobias
Published: August 2013

Previous research indicates that social relationships can influence the probability of successfully finding a first job. This paper contributes to this field of research by empirically analysing the rarely studied question, if social networks can help adolescents find an apprenticeship in the strongly company-based vocational training system of Germany. In contrast to most previous studies, not only the youth's networks, but also their mothers' networks are taken into account. In addition to the social, the ethnic composition of the networks is also considered. Event data analyses of German panel data on natives and migrants from the project ‘Young Immigrants in the German and Israeli Educational System’ show that adolescents' networks have no effect on the success of an apprenticeship search. In contrast, the mothers' networks play a crucial role.
Labour Market Prospects of Swiss Career Entrants after Completion of Vocational Education and Training
Authors: Salvisberg Alexander , Sacchi Stefan
Published: August 2013

This study seeks to find the reasons for the rising risk of unemployment for people who have completed basic vocational education and training (VET) in Switzerland. We focus on the long-term structural shift on the demand side of the labour market and its consequences for new entrants' chances of employment in the labour force. A detailed analysis of the development of vacancies for such ‘career entrants' in the time period 2001 to 2011 suggests that neither a growing occupational mismatch nor a general shift in the level of education to the disadvantage of workers with vocational education can be made responsible for the rising unemployment of labour market entrants. Instead, the available evidence indicates that a diminishing part of the vacancies suited for VET graduates remains open to entrants because of the increasing job requirements with regard to work experience and further education. Basic vocational education and training alone is increasingly less a guarantee for a smooth entry into the working world.
Tactical proficiency among table tennis players with and without intellectual disabilities
Authors: Van Biesen Debbie , Mactavish Jennifer , Vanlandewijck Yves
Published: August 2013

The effect of intellectual impairment on sports performance has received limited attention by researchers. As a contribution to closing this gap, the purpose of the present investigation was to examine the differences in tactical proficiency between table tennis players with and without intellectual disabilities (ID). These groups were matched for training‐volume and experience and consisted of 41 male (age = 27±8) and 30 female (age= 28±8) elite players with ID and a reference group of 12 male (age= 24±12) and 5 female (age= 20±9) players without ID. In two different test settings – one a World Championship and the other a training camp – the players in each group performed 60 semi‐standardised rallies against the same opponent. Players were told that 12 sets of five identical services would be delivered, and their goal was to return the service with the intention of ‘winning the point’. The test results were validated for this study, to compute tactical proficiency scores (maximal score of eight points) for each player. A two‐way Analysis of Variance (ANOVA) revealed significantly lower proficiency scores for players with ID than for those without ID. Repeated‐measures ANOVA revealed that within each series of five rallies, starting with identical services, all participants were able to significantly improve their tactical proficiency gradually, but players without ID scored 4.3±0.5 from the first ball on, and while athletes with ID only 3.3±0.7 after five balls. The results of this study indicate that ID is associated with decreased tactical proficiency in table tennis.