bluuebunny/crossref_metadata_2025 huggingface dataset:
An experimental study of leadership institutions in collective action games
Authors: Sahin Selhan Garip , Eckel Catherine , Komai Mana
Published: May 2015

We investigate the effectiveness of two leadership institutions in each of two games: a weakest link and a linear public good game. An “Exemplar” leader is a first mover who commits to a level of contribution; a “Manager” is a first mover who makes cheap talk suggestions to the team members. Our results show that both leadership institutions reduce coordination failures as compared to a simultaneous move, baseline scenario with no leader. Although the Manager treatment seems to be slightly more effective at the outset, both leadership institutions significantly and equally improve contributions in the coordination game over time. According to our results none of the leadership institutions seem effective in the linear public good game. This may be due to the fact that our marginal per capita return is rather large, keeping the contribution levels high regardless of the treatment. Subjects who choose to free ride continue to do so with or without leaders, and subjects who choose to be cooperative do not become discouraged by others’ lack of cooperation. These results both replicate earlier findings and allow direct comparison across similar games.
Cotranslational incorporation of non‐standard amino acids using cell‐free protein synthesis
Authors: Quast Robert B. , Mrusek Devid , Hoffmeister Christian , Sonnabend Andrei , Kubick Stefan
Published: May 2015

Over the last years protein engineering using non‐standard amino acids has gained increasing attention. As a result, improved methods are now available, enabling the efficient and directed cotranslational incorporation of various non‐standard amino acids to equip proteins with desired characteristics. In this context, the utilization of cell‐free protein synthesis is particularly useful due to the direct accessibility of the translational machinery and synthesized proteins without having to maintain a vital cellular host. We review prominent methods for the incorporation of non‐standard amino acids into proteins using cell‐free protein synthesis. Furthermore, a list of non‐standard amino acids that have been successfully incorporated into proteins in cell‐free systems together with selected applications is provided.
Yes‐Associated Protein is up‐regulated by mechanical overload and is sufficient to induce skeletal muscle hypertrophy
Authors: Goodman Craig A. , Dietz Jason M. , Jacobs Brittany L. , McNally Rachel M. , You Jae-Sung , Hornberger Troy A.
Published: May 2015

Mechanically‐induced skeletal muscle growth is regulated by mammalian/mechanistic target of rapamycin complex 1 (mTORC1). Yes‐Associated Protein (YAP) is a mechanically‐sensitive, and growth‐related, transcriptional co‐activator that can regulate mTORC1. Here we show that, in skeletal muscle, mechanical overload promotes an increase in YAP expression; however, the time course of YAP expression is markedly different from that of mTORC1 activation. We also show that the overexpression of YAP induces hypertrophy via an mTORC1‐independent mechanism. Finally, we provide preliminary evidence of possible mediators of YAP‐induced hypertrophy (e.g. increased MyoD and c‐Myc expression, and decreased Smad2/3 activity and muscle ring finger 1 (MuRF1) expression).
Asymmetric consequences of radical innovations on category representations of competing brands
Authors: Bagga Charan K. , Noseworthy Theodore J. , Dawar Niraj
Published: May 2015

A cognitive level account of when and why radical innovations impact category representations of competing brands is developed and tested. The results suggest that competing brands are affected only when a dominant brand introduces a radical innovation that alters a core category attribute. Such an innovation leads consumers to see competing brands as less typical of the category with diminished evaluations. Crucially, neither core radical innovations introduced by a non‐dominant brand nor equally radical innovations that alter peripheral (non‐core) attributes have any impact on consumers' perceptions of competing brands. Implications for consumer preference formation and competition in the context of radical innovation are drawn.
When one desires too much of a good thing: The compromise effect under maximizing tendencies
Authors: Mao Wen
Published: May 2015

The maximizing tendency denotes individuals' predisposition to look for the best option rather than settling for something that passes an internal threshold of acceptability. This research examines how maximizing affects the compromise effect: the preference for an option with relatively intermediate attribute values. Results show that maximizers attempt to maximize gains on all attributes (rather than to rely on a single, most important attribute as satisficers do) and make more compensatory tradeoffs, which leads to more often choosing a compromise option (Studies 2 & 3). Results held whether maximization was measured as an individual difference variable (Studies 1 & 2) or activated as a decision mindset (Study 3). When asked to make decisions for a (fictional) prototypical maximizer, however, people intuited fewer compromise choices (Study 4). This article concludes by discussing relevant theories on cognitive capacity, regulatory focus, and choice context effects, and by offering tangible suggestions for follow‐up research.
Concomitant inactivation of the p53‐ and pRB‐ functional pathways predicts resistance to DNA damaging drugs in breast cancer in vivo
Authors: Knappskog Stian , Berge Elisabet O. , Chrisanthar Ranjan , Geisler Stephanie , Staalesen Vidar , Leirvaag Beryl , Yndestad Synnøve , de Faveri Elise , Karlsen Bård O. , Wedge David C. , Akslen Lars A. , Lilleng Peer K. , Løkkevik Erik , Lundgren Steinar , Østenstad Bjørn , Risberg Terje , Mjaaland Ingvild , Aas Turid , Lønning Per E.
Published: May 2015

Chemoresistance is the main obstacle to cancer cure. Contrasting studies focusing on single gene mutations, we hypothesize chemoresistance to be due to inactivation of key pathways affecting cellular mechanisms such as apoptosis, senescence, or DNA repair. In support of this hypothesis, we have previously shown inactivation of either TP53 or its key activators CHK2 and ATM to predict resistance to DNA damaging drugs in breast cancer better than TP53 mutations alone. Further, we hypothesized that redundant pathway(s) may compensate for loss of p53‐pathway signaling and that these are inactivated as well in resistant tumour cells. Here, we assessed genetic alterations of the retinoblastoma gene (RB1) and its key regulators: Cyclin D and E as well as their inhibitors p16 and p27. In an exploratory cohort of 69 patients selected from two prospective studies treated with either doxorubicin monotherapy or 5‐FU and mitomycin for locally advanced breast cancers, we found defects in the pRB‐pathway to be associated with therapy resistance (p‐values ranging from 0.001 to 0.094, depending on the cut‐off value applied to p27 expression levels). Although statistically weaker, we observed confirmatory associations in a validation cohort from another prospective study (n = 107 patients treated with neoadjuvant epirubicin monotherapy; p‐values ranging from 7.0 × 10−4 to 0.001 in the combined data sets). Importantly, inactivation of the p53‐and the pRB‐pathways in concert predicted resistance to therapy more strongly than each of the two pathways assessed individually (exploratory cohort: p‐values ranging from 3.9 × 10−6 to 7.5 × 10−3 depending on cut‐off values applied to ATM and p27 mRNA expression levels). Again, similar findings were confirmed in the validation cohort, with p‐values ranging from 6.0 × 10−7 to 6.5 × 10−5 in the combined data sets. Our findings strongly indicate that concomitant inactivation of the p53‐ and pRB‐ pathways predict resistance towards anthracyclines and mitomycin in breast cancer in vivo.
Stable isotopic investigations of modern and charred foxtail millet and the implications for environmental archaeological reconstruction in the western Chinese Loess Plateau
Authors: An Cheng-Bang , Dong Weimiao , Chen Yufeng , Li Hu , Shi Chao , Wang Wei , Zhang Pingyu , Zhao Xueye
Published: May 2015

Stable isotopic analysis of carbon and nitrogen in human and faunal remains has been widely used to reconstruct prehistoric diets and environmental changes. Isotopic analysis of plant remains allows for a more extensive consideration of paleodiets and can potentially provide information about the environment in which the crops were grown. This paper reports the results of δ13C and δ15N analyses performed on modern and charred archaeological foxtail millet samples collected from the western part of the Chinese Loess Plateau. The δ13C mean value of modern samples is lower than that of ancient samples. There is a significant difference between grain and leaf δ15N values. These results challenge the standard assumption in isotope studies that the nitrogen isotope signals of the different part of plants consumed by humans and animals are the same. The 3–5‰ difference between human and animal δ15N values is always regarded as an indicator of whether human diets contained considerable animal protein. The difference between grain and leaf δ15N values makes this assumption problematic in a foxtail millet-dominated society.
The regulation of non-international armed conflicts: Can a privilege of belligerency be envisioned in the law of non-international armed conflicts?
Authors: Kreβ Claus , Mégret Frédéric
Published: May 2015

TheDebatesection of theReviewaims to contribute to reflection on contemporary questions of humanitarian law, policy or action. In this issue of theReview, we invited two experts in international humanitarian law (IHL) –Claus KreβandFrédéric Mégret– to debate on how IHL applicable in non-international armed conflict (NIAC) should develop. In the two pieces that follow, Professor Kreβ submits for debate a new norm of international law outlawing NIACs – ajus contra bellum internum– with a corresponding set of rules applicable in NIACs – ajus in bello interno. Thejus in bello internowould give the “privilege of belligerency” – akin to combatants' privilege in international armed conflicts – to non-State actors in NIACs, providing an incentive for them to comply with these new rules of civil war. Frédéric Mégret critically examines the proposed privilege of belligerency, pointing out its problematic aspects and positing that the creation of such a privilege is, in fact, not desirable.
Type I interferons regulate eomesodermin expression and the development of unconventional memory CD8+ T cells
Authors: Martinet Valérie , Tonon Sandrine , Torres David , Azouz Abdulkader , Nguyen Muriel , Kohler Arnaud , Flamand Véronique , Mao Chai-An , Klein William H. , Leo Oberdan , Goriely Stanislas
Published: May 2015

CD8+ T-cell memory phenotype and function are acquired after antigen-driven activation. Memory-like cells may also arise in absence of antigenic exposure in the thymus or in the periphery. Eomesodermin (Eomes) is a key transcription factor for the development of these unconventional memory cells. Herein, we show that type I interferon signalling in CD8+ T cells directly activates Eomes gene expression. Consistent with this observation, the phenotype, function and age-dependent expansion of ‘virtual memory’ CD8+ T cells are strongly affected in absence of type I interferon signalling. In addition, type I interferons induce a sustained expansion of ‘virtual memory’ CD8+ T cells in an Eomes-dependent fashion. We further show that the development of ‘innate thymic’ CD8+ T cells is dependent on the same pathway. In conclusion, we demonstrate that type I interferon signalling in CD8+ T cells drives Eomes expression and thereby regulates the function and homeostasis of memory-like CD8+ T cells.
The spinning apparatus of webspinners – functional-morphology, morphometrics and spinning behaviour
Authors: Büsse Sebastian , Hörnschemeyer Thomas , Hohu Kyle , McMillan David , Edgerly Janice S.
Published: May 2015

Webspinners (Insecta: Embioptera) have a distinctly unique behaviour with related morphological characteristics. Producing silk with the basitarsomeres of their forelegs plays a crucial role in the lives of these insects – providing shelter and protection. The correlation between body size, morphology and morphometrics of the spinning apparatus and the spinning behaviour of Embioptera was investigated for seven species using state-of-the-art methodology for behavioural as well as for morphological approaches. Independent contrast analysis revealed correlations between morphometric characters and body size. Larger webspinners in this study have glands with greater reservoir volume, but in proportionally smaller tarsi relative to body size than in the smaller species. Furthermore, we present a detailed description and review of the spinning apparatus in Embioptera in comparison to other arthropods and substantiate the possible homology of the embiopteran silk glands to class III dermal silk glands of insects.
BRET evidence that β2 adrenergic receptors do not oligomerize in cells
Authors: Lan Tien-Hung , Liu Qiuju , Li Chunman , Wu Guangyu , Steyaert Jan , Lambert Nevin A.
Published: May 2015

Bioluminescence resonance energy transfer (BRET) is often used to study association of membrane proteins and in particular oligomerization of G protein-coupled receptors (GPCRs). Oligomerization of class A GPCRs is controversial, in part because the methods used to study this question are not completely understood. Here we reconsider oligomerization of the class A β2 adrenergic receptor (β2AR) and reevaluate BRET titration as a method to study membrane protein association. Using inducible expression of the energy acceptor at multiple levels of donor expression we find that BRET between β2AR protomers is directly proportional to the density of the acceptor up to ~3,000 acceptors μm−2 and does not depend on the density of the donor or on the acceptor:donor (A:D) stoichiometry. In contrast, BRET between tightly-associating control proteins does not depend on the density of the acceptor, but does depend on the density of the donor and on the A:D ratio. We also find that the standard frameworks used to interpret BRET titration experiments rely on simplifying assumptions that are frequently invalid. These results suggest that β2ARs do not oligomerize in cells and demonstrate a reliable method of assessing membrane protein association with BRET.
Selectivity Mechanism of the Voltage-gated Proton Channel, HV1
Authors: Dudev Todor , Musset Boris , Morgan Deri , Cherny Vladimir V. , Smith Susan M. E. , Mazmanian Karine , DeCoursey Thomas E. , Lim Carmay
Published: May 2015

Voltage-gated proton channels, HV1, trigger bioluminescence in dinoflagellates, enable calcification in coccolithophores and play multifarious roles in human health. Because the proton concentration is minuscule, exquisite selectivity for protons over other ions is critical to HV1 function. The selectivity of the open HV1 channel requires an aspartate near an arginine in the selectivity filter (SF), a narrow region that dictates proton selectivity, but the mechanism of proton selectivity is unknown. Here we use a reduced quantum model to elucidate how the Asp–Arg SF selects protons but excludes other ions. Attached to a ring scaffold, the Asp and Arg side chains formed bidentate hydrogen bonds that occlude the pore. Introducing H3O+ protonated the SF, breaking the Asp–Arg linkage and opening the conduction pathway, whereas Na+ or Cl– was trapped by the SF residue of opposite charge, leaving the linkage intact, thus preventing permeation. An Asp–Lys SF behaved like the Asp–Arg one and was experimentally verified to be proton-selective, as predicted. Hence, interacting acidic and basic residues form favorable AspH0–H2O0–Arg+ interactions with hydronium but unfavorable Asp––X–/X+–Arg+ interactions with anions/cations. This proposed mechanism may apply to other proton-selective molecules engaged in bioenergetics, homeostasis and signaling.
A new method for the synthesis of LiNi1/3Co1/3Mn1/3O2 from waste lithium ion batteries
Authors: Yao Lu , Feng Yong , Xi Guoxi
Published: May 2015

Re-synthesis of a new cathode material from waste LIBS using citric acid as a leaching agent and complexing agent.
The Aβ40 and Aβ42 peptides self-assemble into separate homomolecular fibrils in binary mixtures but cross-react during primary nucleation
Authors: Cukalevski Risto , Yang Xiaoting , Meisl Georg , Weininger Ulrich , Bernfur Katja , Frohm Birgitta , Knowles Tuomas P. J. , Linse Sara
Published: May 2015

Reaction network starting from monomer mixtures of Aβ40 and Aβ42. Interaction at the level of primary nucleation only accelerates Aβ40 fibril formation. Separate fibrils form as secondary nucleation and elongation are highly specific.
A near-infrared fluorescent probe for the selective detection of HNO in living cells and in vivo
Authors: Liu Ping , Jing Xiaotong , Yu Fabiao , Lv Changjun , Chen Lingxin
Published: May 2015

We present a near-infrared fluorescent probe for the detection of nitroxyl (HNO) in living cells and in mice.
Catalytic amidation of unactivated ester derivatives mediated by trifluoroethanol
Authors: Caldwell Nicola , Jamieson Craig , Simpson Iain , Watson Allan J. B.
Published: May 2015

A practical, catalytic protocol for amidation of unactivated esters has been developed using cheap and readily available reagents.
Incarceration of one or two phosphate or arsenate species within nanojars, capped nanojars and nanohelicages: helical chirality from two closely-spaced, head-to-head PO43−or AsO43−ions
Authors: Mezei Gellert
Published: May 2015

Phosphate and arsenate ions are bound with unprecedented strength by self-assembled nanohosts with protein-like anion binding cavities.
Effect of ethylenediamine on the formation of macro, micro, and nanostructures based on [WVI(Cat)2O2]2−
Authors: Pan Ganghuo , Lu Xiaoming , Li Kai , Shen Minghai , Zhao Jing
Published: May 2015

A slight change in the protonation of ethylenediamine affects the nanostructure greatly during crystal formation.
Quasi-combinatorial energy landscapes for nanoalloy structure optimisation
Authors: Schebarchov D. , Wales D. J.
Published: May 2015

Nanoalloy energy landscapes explored in continuous and discrete metric spaces simultaneously.
A real-space stochastic density matrix approach for density functional electronic structure
Authors: Beck Thomas L.
Published: May 2015

A novel stochastic approach aimed at solving for the ground-state one-particle density matrix in density functional theory is developed.
Stimulated emission in cryogenic samples doped with free-base tetraazaporphine
Authors: Arabei Serguei , McCaffrey John G. , Galaup Jean-Pierre , Shafizadeh Niloufar , Crépin Claudine
Published: May 2015

Stimulated emission (SE) is induced in thin cryogenic matrices doped with H2TAP at various wavelengths depending on the laser excitation and the host.
Cationic gold clusters ligated with differently substituted phosphines: effect of substitution on ligand reactivity and binding
Authors: Johnson Grant E. , Olivares Astrid , Hill David , Laskin Julia
Published: May 2015

Loss of substituted phosphine ligands is strongly correlated with the electron donating ability of the phosphorous lone pair. The results indicate that the relative ligand binding energies increase in the order PMe3 < PPhMe2 < PPh2Me < PPh3 < PPh2Cy < PPhCy2 < PCy3.
Flexible supercapacitors based on paper substrates: a new paradigm for low-cost energy storage
Authors: Zhang Yi-Zhou , Wang Yang , Cheng Tao , Lai Wen-Yong , Pang Huan , Huang Wei
Published: May 2015

This review introduces the background, design and applications of paper-based supercapacitors, highlighting their importance for low-cost flexible energy storage.
Gold(i)-catalysed dehydrative formation of ethers from benzylic alcohols and phenols
Authors: Veenboer Richard M. P. , Nolan Steven P.
Published: May 2015

A well-defined NHC–gold(i) complex has been shown highly effective in the formation of ethers from secondary benzylic alcohols and phenols under mild reaction conditions.
Recent advances in microfluidic actuation and micro-object manipulation via surface acoustic waves
Authors: Destgeer Ghulam , Sung Hyung Jin
Published: May 2015

Recent advances in microfluidic actuation and micro-object manipulation by surface acoustic waves have been reviewed.
Instantaneous room temperature bonding of a wide range of non-silicon substrates with poly(dimethylsiloxane) (PDMS) elastomer mediated by a mercaptosilane
Authors: Wu Wenming , Wu Jing , Kim Jae-Heon , Lee Nae Yoon
Published: May 2015

Instantaneous and robust bonding of various non-silicon substrates with PDMS was realized at room temperature within 12 to 17 min by mercaptosilane coating.
Immunogold labeling reveals subcellular localisation of silica nanoparticles in a human blood–brain barrier model
Authors: Ye Dong , Anguissola Sergio , O'Neill Tiina , Dawson Kenneth A.
Published: May 2015

The pre-embedding immunogold labeling electron microscopy was employed to investigate subcellular transport pathways of nanoparticles in a blood–brain barrier model.
Functionalization of nano-graphenes by chimeric peptide engineering
Authors: Shim Gayong , Lee Jaiwoo , Kim Jinyoung , Lee Hee-Jung , Kim Young Bong , Oh Yu-Kyoung
Published: May 2015

7F4D motif can be applied for non-covalent tethering of various functional peptides onto rGO nanosheets for protein delivery or biosensors.
Green synthesis of hyaluronic acid-based silver nanoparticles and their enhanced delivery to CD44+ cancer cells
Authors: Liang Jianming , Zeng Feng , Zhang Meng , Pan Zhenzhen , Chen Yingzhi , Zeng Yuaner , Xu Yong , Xu Qin , Huang Yongzhuo
Published: May 2015

A novel hyaluronic acid (HA)-based strategy for the green synthesis of AgNP was developed, in which HA was used as both the reducer and stabilizer, and the HA-modified AgNP can target CD44-overexpressed cancer cells for improved therapy.
Synthesis, characterization and bifunctional applications of bidentate silver nanoparticle assisted single drop microextraction as a highly sensitive preconcentrating probe for protein analysis
Authors: Shastri Lokesh , Abdelhamid Hani Nasser , Nawaz Mohd , Wu Hui-Fen
Published: May 2015

Synthesis, characterization and bifunctional applications of silver nanoparticles with two different surface capping reagents are reported.
Evaluation of the effects of boron nitride nanotubes functionalized with gum arabic on the differentiation of rat mesenchymal stem cells
Authors: Ferreira Tiago H. , Rocca Antonella , Marino Attilio , Mattoli Virgilio , de Sousa Edesia M. B. , Ciofani Gianni
Published: May 2015

The biocompatibility of boron nitride nanotubes with rat mesenchymal stem cells has been evaluated in terms of cell proliferation and differentiation.
Free nitrous acid breaks down extracellular polymeric substances in waste activated sludge
Authors: Zhang Tingting , Wang Qilin , Khan Javaid , Yuan Zhiguo
Published: May 2015

The chemical breakdown of EPS components by FNA has been proved to account for the improvement of sludge biodegradability in addition to enhanced cell lysis in FNA-based sludge treatment technology.
Enhancement of pump efficiency for an organic distributed feedback laser based on a holographic polymer dispersed liquid crystal as an external light feedback layer
Authors: Liu Lijuan , Xuan Li , Zhang Guiyang , Liu Minghuan , Hu Lifa , Liu Yonggang , Ma Ji
Published: May 2015

A low threshold, high energy conversion organic distributed feedback laser based on a holographic polymer dispersed liquid crystal as an external light feedback layer was reported.
PECAM-1 isoforms, eNOS and endoglin axis in regulation of angiogenesis
Authors: Park Sunyoung , Sorenson Christine M. , Sheibani Nader
Published: May 2015

Vascular development and maintenance of proper vascular function through various regulatory mechanisms are critical to our wellbeing. Delineation of the regulatory processes involved in development of the vascular system and its function is one of the most important topics in human physiology and pathophysiology. Platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31), a cell adhesion molecule with proangiogenic and proinflammatory activity, has been the subject of numerous studies. In the present review, we look at the important roles that PECAM-1 and its isoforms play during angiogenesis, and its molecular mechanisms of action in the endothelium. In the endothelium, PECAM-1 not only plays a role as an adhesion molecule but also participates in intracellular signalling pathways which have an impact on various cell adhesive mechanisms and endothelial nitric oxide synthase (eNOS) expression and activity. In addition, recent studies from our laboratory have revealed an important relationship between PECAM-1 and endoglin expression. Endoglin is an essential molecule during angiogenesis, vascular development and integrity, and its expression and activity are compromised in the absence of PECAM-1. In the present review we discuss the roles that PECAM-1 isoforms may play in modulation of endothelial cell adhesive mechanisms, eNOS and endoglin expression and activity, and angiogenesis.
Low‐voltage power‐on‐reset circuit with least delay and high accuracy
Authors: Pandey P.
Published: May 2015

A novel method for the generation of the power‐on‐reset (POR) signal needed by the SOC is described. A POR signal is required for initialisation of the logical state in digital systems. To obtain an accurate trip point for the POR, generally a bandgap voltage reference is used along with additional logic. Such logic tends to limit the lowest possible trip point that can be achieved. The proposed implementation of POR is based on a modified bandgap circuit where a supply‐dependent current is injected into the loop. In this case, the reference generation is not explicitly required and thus the trip point can be kept very close to the minimum supply required for the bandgap operation. This implementation also needs very small delay as the required delay is not dependent on supply ramp rates and can be made very small.
CMOS BEOL‐embedded z‐axis accelerometer
Authors: Michalik P. , Sánchez‐Chiva J.M. , Fernández D. , Madrenas J.
Published: May 2015

A first reported complementary metal‐oxide semiconductor (CMOS)‐integrated acceleration sensor obtained through isotropic inter‐metal dielectric (IMD) etching of a back‐end‐of‐line (BEOL) integrated circuit interconnection stack, without any additional substrate etching steps, is presented. The mechanical device composed of a CMOS‐process 8 μm‐thick metal‐via‐metal stack of 135 μm diameter and suspended 2.5 μm over a bottom fixed electrode, has a resonance frequency of 20 kHz, a sensing capacitance of 50 fF with sensitivity 14 aF/G and it is integrated on the same substrate with a simple low‐noise amplifier reaching 25 mG of RMS noise measured from 0.25 to 100 Hz bandwidth.
Calibration for accuracy improvement of serial manipulators based on compressed sensing
Authors: Tan N.
Published: May 2015

Geometric errors are the main source of the positioning inaccuracy of robotic manipulators. A novel robot calibration approach is proposed based on compressed sensing to compensate the geometric errors. Simulation results validate that the proposed method improves the accuracy as well as reduces the calibration time.
Charge‐compensated correlated level shifting for single‐stage opamps
Authors: Abdelhamid M.R. , Hussien F.A. , Aboudina M.M.
Published: May 2015

High‐precision analogue circuits suffer from the finite gain and non‐linearity of operational amplifiers (opamps). Correlated level shifting is one efficient technique that provides gain and swing enhancement for switched‐capacitor circuits. Charge‐compensated correlated level shifting is proposed, a modification for the correlated level shifting technique, that improves the efficiency of gain enhancement for single‐stage opamps.
Direct numerical simulation of shear localization and decomposition reactions in shock-loaded HMX crystal
Authors: Austin Ryan A. , Barton Nathan R. , Reaugh John E. , Fried Laurence E.
Published: May 2015

A numerical model is developed to study the shock wave ignition of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) crystal. The model accounts for the coupling between crystal thermal/mechanical responses and chemical reactions that are driven by the temperature field. This allows for the direct numerical simulation of decomposition reactions in the hot spots formed by mechanical loading. The model is used to simulate intragranular pore collapse under shock wave loading. In a reference case: (i) shear-enabled micro-jetting is responsible for a modest extent of reaction in the pore collapse region, and (ii) shear banding is found to be an important mode of localization. The shear bands, which are filled with molten HMX, grow out of the pore collapse region and serve as potential ignition sites. The model predictions of shear banding and reactivity are found to be quite sensitive to the respective flow strengths of the solid and liquid phases. In this regard, it is shown that reasonable assumptions of liquid-HMX viscosity can lead to chemical reactions within the shear bands on a nanosecond time scale.
Influence of doping with alkaline earth metals on the optical properties of thermochromic VO2
Authors: Dietrich Marc K. , Kramm Benedikt G. , Becker Martin , Meyer Bruno K. , Polity Angelika , Klar Peter J.
Published: May 2015

Thin films of doped VO2 were deposited, analyzed, and optimized with regard to their solar energy transmittance (Tsol) and visible/luminous light transmittance (Tlum) which are important parameters in the context of smart window applications in buildings. The doping with alkaline earth metals (AEM) like Mg, Ca, Sr, or Ba increased both Tsol and Tlum due to a bandgap widening and an associated absorption edge blue-shift. Thereby, the brown-yellowish color impression of pure VO2 thin films, which is one major hindrance limiting the usage of VO2 as thermochromic window coating, was overcome. Transparent thin films with excellent switching behavior were prepared by sputtering. Highly doped V1−xMexO2 (Me = Ca, Sr, Ba) kept its excellent thermochromic switching behavior up to x(Me) = Me/(Me + V) = 10 at. % doping level, while the optical bandgap energy was increased from 1.64 eV for undoped VO2 to 2.38 eV for x(Mg) = 7.7 at. %, 1.85 eV for x(Ca) = 7.4 at. %, 1.84 eV for x(Sr) = 6.4 at. % and 1.70 eV for x(Ba) = 6.8 at. %, as well as the absorption edge is blue shifted by increasing AEM contents. Also, the critical temperature ϑc, at which the semiconductor-to-metal transition (SMT) occurs, was decreased by AEM doping, which amounted to about −0.5 K/at. % for all AEM on average. The critical temperature was determined by transmittance-temperature hysteresis measurements. Furthermore, Tsol and Tlum were calculated and were found to be significantly enhanced by AEM doping. Tlum increased from 32.0% in undoped VO2 to 43.4% in VO2 doped with 6.4 at. % Sr. Similar improvements were found for other AEM. The modulation of the solar energy transmittance ΔTsol, which is the difference of the Tsol values in the low and high temperature phase, was almost constant or even slightly increased when the doping level was increased up to about 10 at. % Ca, Sr, or Ba.
The local environment of cobalt in amorphous, polycrystalline and epitaxial anatase TiO2:Co films produced by cobalt ion implantation
Authors: Yildirim O. , Cornelius S. , Smekhova A. , Zykov G. , Gan'shina E. A. , Granovsky A. B. , Hübner R. , Bähtz C. , Potzger K.
Published: May 2015

Amorphous, polycrystalline anatase and epitaxial anatase TiO2 films have been implanted with 5 at. % Co+. The magnetic and structural properties of different microstructures of TiO2:Co, along with the local coordination of the implanted Co atoms within the host lattice are investigated. In amorphous TiO2:Co film, Co atoms are in the (II) oxidation state with a complex coordination and exhibit a paramagnetic response. However, for the TiO2:Co epitaxial and polycrystalline anatase films, Co atoms have a distorted octahedral (II) oxygen coordination assigned to a substitutional environment with traces of metallic Co clusters, which gives a rise to a superparamagnetic behavior. Despite the incorporation of the implanted atoms into the host lattice, high temperature ferromagnetism is absent in the films. On the other hand, it is found that the concentration and size of the implantation-induced nanoclusters and the magnetic properties of TiO2:Co films have a strong dependency on the initial microstructure of TiO2. Consequently, metallic nanocluster formation within ion implantation prepared transition metal doped TiO2 can be suppressed by tuning the film microstructure.
Development of micro-four-point probe in a scanning tunneling microscope for in situ electrical transport measurement
Authors: Ge Jian-Feng , Liu Zhi-Long , Gao Chun-Lei , Qian Dong , Liu Canhua , Jia Jin-Feng
Published: May 2015

Electrons at surface may behave differently from those in bulk of a material. Multi-functional tools are essential in comprehensive studies on a crystal surface. Here, we developed an in situ microscopic four-point probe (4PP) transport measurement system on the basis of a scanning tunneling microscope (STM). In particular, convenient replacement between STM tips and micro-4PPs enables systematic investigations of surface morphology, electronic structure, and electrical transport property of a same sample surface. Performances of the instrument are demonstrated with high-quality STM images, tunneling spectra, and low-noise electrical I-V characteristic curves of a single-layer FeSe film grown on a conductive SrTiO3 surface.
The axisymmetric collapse of a mixed patch and internal wave generation in uniformly stratified rotating fluid
Authors: Holdsworth Amber M. , Sutherland Bruce R.
Published: May 2015

We present an experimental and numerical investigation of the effect of Coriolis forces on the axisymmetric collapse of a uniform mixed region in uniformly stratified fluid. Laboratory experiments were performed on a rotating table in which a mixed patch contained initially in a hollow cylinder was released and so excited internal waves whose properties were analyzed using synthetic schlieren. Numerical simulations restricted to an axisymmetric geometry were run with the experimental parameters to confirm the accuracy of the code and the validity of the axisymmetric approximation. The simulations were then run in larger domains and with wide-ranging parameters exploring the dependence of wave generation upon rotation and the aspect ratio of the mixed patch. Internal waves are found to be generated from the circumference of a shallow aspect-ratio mixed patch, with the radial and vertical wavelengths scaling as the mixed-layer depth. In rotating fluid, the energy spectrum revealed that pairs of wavepackets were generated, one with near-inertial frequencies and one with frequencies near the buoyancy frequency. Energy transport due to the waves was most significant during the first 6 wave periods. However, for very low Rossby number Ro ∼ 0.1, internal wave generation continued over relatively longer times as a consequence of undulations of the geostrophically adjusting mixed patch.
A proof of the conjecture by Carpentier-De Sole-Kac
Authors: Stubis Keaton
Published: May 2015

We prove the following conjecture by Carpentier, De Sole, and Kac: let K be a differential field and R be a differential subring of K. Let M be a matrix whose elements are differential operators with coefficients in R. Then, if M has degeneracy degree 1, the Dieudonné determinant of M lies in R.
Realization of optical bistability and multistability in Landau-quantized graphene
Authors: Hamedi H. R. , Asadpour S. H.
Published: May 2015

The solution of input-output curves in an optical ring cavity containing Landau-quantized graphene is theoretically investigated taking the advantage of density-matrix method. It is found that under the action of strong magnetic and infrared laser fields, one can efficiently reduce the threshold of the onset of optical bistability (OB) at resonance condition. At non-resonance condition, we observed that graphene metamaterial can support the possibility to obtain optical multistability (OM), which is more practical in all-optical switching or coding elements. We present an analytical approach to elucidate our simulations. Due to very high infrared optical nonlinearity of graphene stemming from very unique and unusual properties of quantized Landau levels near the Dirac point, such controllability on OB and OM may provide new technological possibilities in solid state quantum information science.
Spontaneous formation of nanostructures by surface spinodal decomposition in GaAs1−xBix epilayers
Authors: Luna E. , Wu M. , Puustinen J. , Guina M. , Trampert A.
Published: May 2015

We report on the spontaneous formation of lateral composition modulations (LCMs) in Ga(As,Bi) epilayers grown by low-temperature (<300 °C) molecular beam epitaxy (MBE) on GaAs(001). Both cross-section and plan-view transmission electron microscopy techniques are used to investigate the nature of the LCMs, consisting of Bi-rich cylinder-like nanostructures lying along the [001] growth direction. The observed LCMs are the consequence of a two-dimensional phase separation process occurring at the surface of the growing epilayers, and their columnar nature is consistent with a surface-directed spinodal decomposition process. Although LCMs are thermodynamically driven, we show how they can be kinetically controlled, in particular, through the As/Ga flux ratio and the substrate temperature. This is a result of LCMs developing from surface atomic diffusion processes, since the atomic dimer configurations on the surface alter adatom diffusivity. The significant role of the surface reconstructions is also discussed.
Growth evolution of AlN films on silicon (111) substrates by pulsed laser deposition
Authors: Wang Haiyan , Wang Wenliang , Yang Weijia , Zhou Shizhong , Lin Zhiting , Li Guoqiang
Published: May 2015

AlN films with various thicknesses have been grown on Si(111) substrates by pulsed laser deposition (PLD). The surface morphology and structural property of the as-grown AlN films have been investigated carefully to comprehensively explore the epitaxial behavior. The ∼2 nm-thick AlN film initially grown on Si substrate exhibits an atomically flat surface with a root-mean-square surface roughness of 0.23 nm. As the thickness increases, AlN grains gradually grow larger, causing a relatively rough surface. The surface morphology of ∼120 nm-thick AlN film indicates that AlN islands coalesce together and eventually form AlN layers. The decreasing growth rate from 240 to 180 nm/h is a direct evidence that the growth mode of AlN films grown on Si substrates by PLD changes from the islands growth to the layer growth. The evolution of AlN films throughout the growth is studied deeply, and its corresponding growth mechanism is hence proposed. These results are instructional for the growth of high-quality nitride films on Si substrates by PLD, and of great interest for the fabrication of AlN-based devices.
Heat transport by coherent Rayleigh-Bénard convection
Authors: Waleffe Fabian , Boonkasame Anakewit , Smith Leslie M.
Published: May 2015

Steady but generally unstable solutions of the 2D Boussinesq equations are obtained for no-slip boundary conditions and Prandtl number 7. The primary solution that bifurcates from the conduction state at Rayleigh number Ra ≈ 1708 has been calculated up to Ra ≈ 5.106 and its Nusselt number is Nu ∼ 0.143 Ra0.28 with a delicate spiral structure in the temperature field. Another solution that maximizes Nu over the horizontal wavenumber has been calculated up to Ra = 109 and scales as Nu ∼ 0.115 Ra0.31 for 107 < Ra ≤ 109, quite similar to 3D turbulent data that show Nu ∼ 0.105 Ra0.31 in that range. The optimum solution is a simple yet multi-scale coherent solution whose horizontal wavenumber scales as 0.133 Ra0.217. That solution is unstable to larger scale perturbations and in particular to mean shear flows, yet it appears to be relevant as a backbone for turbulent solutions, possibly setting the scale, strength, and spacing of elemental plumes.
Self-assembly dynamics for the transition of a globular aggregate to a fibril network of lysozyme proteins via a coarse-grained Monte Carlo simulation
Authors: Pandey R. B. , Farmer B. L. , Gerstman Bernard S.
Published: May 2015

The self-organizing dynamics of lysozymes (an amyloid protein with 148 residues) with different numbers of protein chains, Nc = 1,5,10, and 15 (concentration 0.004 – 0.063) is studied by a coarse-grained Monte Carlo simulation with knowledge-based residue-residue interactions. The dynamics of an isolated lysozyme (Nc = 1) is ultra-slow (quasi-static) at low temperatures and becomes diffusive asymptotically on raising the temperature. In contrast, the presence of interacting proteins leads to concentration induced protein diffusion at low temperatures and concentration-tempering sub-diffusion at high temperatures. Variation of the radius of gyration of the protein with temperature shows a systematic transition from a globular structure (at low T) to a random coil (high T) conformation when the proteins are isolated. The crossover from globular to random coil becomes sharper upon increasing the protein concentration (i.e. with Nc = 5,10), with larger Rg at higher temperatures and concentration; Rg becomes smaller on adding more protein chains (e.g. Nc = 15) a non-monotonic response to protein concentration. Analysis of the structure factor (S(q)) provides an estimate of the effective dimension (D ≥ 3, globular conformation at low temperature, and D ∼ 1.7, random coil, at high temperatures) of the isolated protein. With many interacting proteins, the morphology of the self-assembly varies with scale, i.e. at the low temperature (T = 0.015), D ∼ 2.9 on the scale comparable to the radius of gyration of the protein, and D ∼ 2.3 at the large scale over the entire sample. The global network of fibrils appears at high temperature (T = 0.021) with D ∼ 1.7 (i.e. a random coil morphology at large scale) involving tenuous distribution of micro-globules (at small scales).
A multi-criteria decision aid methodology to design electric vehicles public charging networks
Authors: Raposo João , Rodrigues Ana , Silva Carlos , Dentinho Tomaz
Published: May 2015

This article presents a new multi-criteria decision aid methodology, dynamic-PROMETHEE, here used to design electric vehicle charging networks. In applying this methodology to a Portuguese city, results suggest that it is effective in designing electric vehicle charging networks, generating time and policy based scenarios, considering offer and demand and the city’s urban structure. Dynamic-PROMETHE adds to the already known PROMETHEE’s characteristics other useful features, such as decision memory over time, versatility and adaptability. The case study, used here to present the dynamic-PROMETHEE, served as inspiration and base to create this new methodology. It can be used to model different problems and scenarios that may present similar requirement characteristics.
Determinants of the low uptake of HIV-related intervention services by female sex workers in Shenzhen, China: an observational study (2009–2012)
Authors: Cai Rui , Tan Jingguang , Chen Lin , Looman Caspar W. N. , Richardus Jan Hendrik , de Vlas Sake J.
Published: May 2015

Background
Female sex workers (FSWs) are highly vulnerable to HIV but make little use of HIV-related intervention services provided by the Chinese government. Determinants of the low uptake of HIV services by FSWs in Shenzhen, Guangdong province were investigated. Methods: FSWs were recruited by venue-based sampling; 1656 FSWs were interviewed about sociodemographics, behaviours and uptake of HIV-related intervention services. Determinants of no uptake of HIV testing, condom promotion, and peer education were determined through logistic regression. The association between uptake of HIV-related services, condom use and HIV-related knowledge was also assessed. Results: The overall uptake of HIV testing, condom promotion, and peer education by FSWs was 21.5%, 47.8% and 28.0%, respectively. Young age and shorter duration of working in Shenzhen were statistically significantly correlated with no uptake of all three interventions. Uptake of these services was positively associated with consistent condom use and good HIV-related knowledge. Conclusions: The uptake of HIV-related intervention services by FSWs is low in Shenzhen. As their uptake is positively associated with condom use and HIV-related knowledge, it is necessary to intensify promotion of these, focusing on young and recently started FSWs.
Behavioral idiosyncrasy reveals genetic control of phenotypic variability
Authors: Ayroles Julien F. , Buchanan Sean M. , O’Leary Chelsea , Skutt-Kakaria Kyobi , Grenier Jennifer K. , Clark Andrew G. , Hartl Daniel L. , de Bivort Benjamin L.
Published: May 2015

Significance

If we could rear genetically identical individuals from a variety of genetic backgrounds and rear them in the same environment, how much phenotypic variation between individuals of the same genotype would we see? Would different genetic backgrounds differ in their degree of variability? What would account for these differences? We used
Drosophila
inbred lines to address these questions focusing on variability in locomotor handedness. We show that different genotypes vary dramatically in their propensity for variability, that phenotypic variability itself, as a trait, can be heritable, and that loci affecting variability can be mapped. The genetic control of variability has received little attention in quantitative genetics despite the important role variability plays in explaining phenotypic variation between individuals.
The treatment of tax as expropriation in International investor–state arbitration
Authors: Lazem Ali , Bantekas Ilias
Published: May 2015

Domestic tax measures are treated by investment tribunals as a fundamental attribute of sovereignty and constitute lex specialis in relation to the general rule on expropriation under customary international law. Although both direct and indirect expropriation are possible through the imposition of tax measures, in practice such findings are rare and further restricted by joint tax vetoes and tax exclusion clauses in international investment treaties and bilateral tax treaties. This inclination in favour of host states is further confirmed by the requirement that the conduct requirements for expropriation be satisfied, although the role of conduct requirements is to differentiate between lawful and unlawful expropriation. The lex specialis character of tax measures suggests, particularly as a result of cases such as Burlington, that investment tribunals are unlikely to lower the threshold of state liability for expropriation arising from tax measures and are in fact likely to view the substantial deprivation standard very strictly and in a manner that requires a total deprivation of property.