bluuebunny/crossref_metadata_2025 huggingface dataset:
Correction: Silver-mediated direct phosphorylation of benzothiazoles and thiazoles with diarylphosphine oxides
Authors: Zhang Hui-Jun , Lin Weidong , Wu Zhengjian , Ruan Wenqing , Wen Ting-Bin
Published: November 2015

Correction for ‘Silver-mediated direct phosphorylation of benzothiazoles and thiazoles with diarylphosphine oxides’ by Hui-Jun Zhang et al., Chem. Commun., 2015, 51, 3450–3453.
Ullmann coupling mediated assembly of an electrically driven altitudinal molecular rotor
Authors: Murphy Colin J. , Smith Zachary C. , Pronschinski Alex , Lewis Emily A. , Liriano Melissa L. , Wong Chloe , Ivimey Christopher J. , Duffy Mitchell , Musial Wojciech , J. Therrien Andrew , Thomas III Samuel W. , Sykes E. Charles H.
Published: November 2015

The surface-mediated Ullmann coupling reaction enables the formation of chemically tunable, electrically driven molecular rotors.
Magnetic structures of the low temperature phase of Mn3(VO4)2– towards understanding magnetic ordering between adjacent Kagomé layers
Authors: Clemens Oliver , Rohrer Jochen , Nénert Gwilherm
Published: November 2015

The magnetic structures of the low-temperature phase of Mn3(VO4)2are solved and discussed in this article.
CoxC encased in carbon nanotubes: an efficient oxygen reduction catalyst under both acidic and alkaline conditions
Authors: Chen Lisong , Cui Xiangzhi , Wang Qingsong , Zhang Xiaohua , Wan Gang , Cui Fangming , Wei Chenyang , Shi Jianlin
Published: November 2015

CoxC encased in carbon nanotubes is synthesized using a facile co-pyrolysis method and can serve as a highly efficient oxygen reduction catalyst under both acidic and alkaline conditions.
The degradation behaviour of nine diverse contaminants in urban surface water and wastewater prior to water treatment
Authors: Cormier Guillaume , Barbeau Benoit , Arp Hans Peter H. , Sauvé Sébastien
Published: November 2015

An increasing diversity of emerging contaminants are entering urban surface water and wastewater, posing unknown risks for the environment.
Nanoporous microscale microbial incubators
Authors: Ge Zhifei , Girguis Peter R. , Buie Cullen R.
Published: November 2015

Nanoporous microscale microbial incubators allow communities of microbes to grow in physical isolation while maintaining chemical communication, facilitating the study of interactions within diverse communities.
Host–guest complexation of di-cyclohexanocucurbit[6]uril and hexa-cyclohexanocucurbit[6]uril with alkyldiammonium ions: a comparative study
Authors: Fang Guo-Sheng , Sun Wen-Qi , Zhao Wen-Xuan , Lin Rui-Lian , Tao Zhu , Liu Jing-Xin
Published: November 2015

The host–guest complexation of Cy2Q[6] and Cy6Q[6] with alkyldiammonium ions has been investigated, indicating the conformation of the alkyl chains and the thermodynamic data in the complexation process are strongly affected by the cavity shape of the host and the hydrophobic effect.
Iron-catalyzed transfer hydrogenation of imines assisted by an iron-based Lewis acid
Authors: Pan Hui-Jie , Ng Teng Wei , Zhao Yu
Published: November 2015

An iron-catalyzed transfer hydrogenation of N-aryl and N-alkyl imines using isopropanol as the hydrogen donor is reported for the first time.
Enhancement of the crosslink density, glass transition temperature, and strength of epoxy resin by using functionalized graphene oxide co-curing agents
Authors: Yu Jin Won , Jung Jin , Choi Yong-Mun , Choi Jae Hun , Yu Jaesang , Lee Jae Kwan , You Nam-Ho , Goh Munju
Published: November 2015

Epoxy nanocomposites are fabricated by using diamine-functionalized GO and exhibit highTg, tensile strength, and crosslink density.
Novel graphene/polyaniline/MnOx3D-hydrogels obtained by controlled morphology of MnOxin the graphene/polyaniline matrix for high performance binder-free supercapacitor electrodes
Authors: Jayakumar Anjali , Yoon Yong-Jin , Wang Ronghua , Lee Jong-Min
Published: November 2015

Graphene/polyaniline/MnOx(PGM-HCl) hydrogel prepared in an acidic environment using hydrochloric acidviaa simple hydrothermal reaction for high-performance supercapacitors.
Stability behaviour of antiretroviral drugs and their combinations. 1: characterization of tenofovir disoproxil fumarate degradation products by mass spectrometry
Authors: Kurmi Moolchand , Golla Vijaya Madhyanapu , Kumar Sanjay , Sahu Archana , Singh Saranjit
Published: November 2015

The investigation established the intrinsic degradation behaviour of tenofovir disoproxil fumarate in solid and solution states.
One-step melamine-assisted synthesis of graphene-supported AuPt@Au nanocrystals for enhanced catalytic reduction of p-nitrophenol
Authors: Liu Qi , Xu Yan-Ru , Wang Ai-Jun , Feng Jiu-Ju
Published: November 2015

Core–shell AuPt@Au NCs/rGO was facilely prepared by a one-step melamine-assisted method, which exhibited enhanced catalytic performance for p-nitrophenol reduction.
Water opens the door to organolithiums and Grignard reagents: exploring and comparing the reactivity of highly polar organometallic compounds in unconventional reaction media towards the synthesis of tetrahydrofurans
Authors: Cicco Luciana , Sblendorio Stefania , Mansueto Rosmara , Perna Filippo M. , Salomone Antonio , Florio Saverio , Capriati Vito
Published: November 2015

Grignard and organolithium reagents undergo smooth nucleophilic additions to γ-chloroketones “on water”.
When block copolymer self-assembly in hierarchically ordered honeycomb films depicts the breath figure process
Authors: Escalé Pierre , Save Maud , Billon Laurent , Ruokolainen Janne , Rubatat Laurent
Published: November 2015

A detailed observation of the block copolymer self-assembly, kinetically trapped during the breath figure process, and used as an imprint to elucidate the complex honeycomb film formation.
Silicon de novo: energy filtering and enhanced thermoelectric performances of nanocrystalline silicon and silicon alloys
Authors: Narducci Dario , Frabboni Stefano , Zianni Xanthippi
Published: November 2015

Energy filtering due to second-phase precipitation in nanocrystalline silicon may lead to remarkable improvements of its thermoelectric power factor.
Evidence for caspase-dependent programmed cell death along with repair processes in affected skeletal muscle fibres in patients with mitochondrial disorders
Authors: Guglielmi Valeria , Vattemi Gaetano , Chignola Roberto , Chiarini Anna , Marini Matteo , Dal Prà Ilaria , Di Chio Marzia , Chiamulera Cristiano , Armato Ubaldo , Tomelleri Giuliano
Published: November 2015

Mitochondrial disorders are heterogeneous multisystemic disorders due to impaired oxidative phosphorylation causing defective mitochondrial energy production. Common histological hallmarks of mitochondrial disorders are RRFs (ragged red fibres), muscle fibres with abnormal focal accumulations of mitochondria. In contrast with the growing understanding of the genetic basis of mitochondrial disorders, the fate of phenotypically affected muscle fibres remains largely unknown. We investigated PCD (programmed cell death) in muscle of 17 patients with mitochondrial respiratory chain dysfunction. We documented that in affected muscle fibres, nuclear chromatin is condensed in lumpy irregular masses and cytochrome c is released into the cytosol to activate, along with Apaf-1 (apoptotic protease-activating factor 1), caspase 9 that, in turn, activates effector caspase 3, caspase 6, and caspase 7, suggesting the execution of the intrinsic apoptotic pathway. Whereas active caspase 3 underwent nuclear translocation, AIF (apoptosis-inducing factor) mainly stayed within mitochondria, into which an up-regulated Bax is relocated. The significant increase in caspase 2, caspase 3 and caspase 6 activity strongly suggest that the cell death programme is caspase-dependent and the activation of caspase 2 together with PUMA (p53 up-regulated modulator of apoptosis) up-regulation point to a role for oxidative stress in triggering the intrinsic pathway. Concurrently, in muscle of patients, the number of satellite cells was significantly increased and myonuclei were detected at different stages of myogenic differentiation, indicating that a reparative programme is ongoing in muscle of patients with mitochondrial disorders. Together, these data suggest that, in patients with mitochondrial disorders, affected muscle fibres are trapped in a mitochondria-regulated caspase-dependent PCD while repairing events take place.
Descriptive Analysis: Survey of Direct and Indirect Interventions for Persons With Dementia-Based Communication Disorders
Authors: Paul Nancy , Mehrhoff Joni
Published: November 2015

Results of a survey made available to SIG 2 and SIG 15 affiliates via the SIG listservs revealed information on direct and indirect interventions utilized for persons with dementia-based communication disorders. Fifty-eight practicing speech-language pathologists (SLPs) participated and reported using the following direct interventions most frequently: specific verbal instruction, cognitive stimulation, memory wallet, spaced retrieval, and errorless learning. The overwhelming majority of participants utilized caregiver training as the most frequent indirect technique. Barriers and facilitators to providing intervention for persons with dementia-related communication disorders were identified.
Direct and Indirect Interventions for Cognitive-Communication Disorders of Dementia
Authors: Hopper Tammy , Douglas Natalie , Khayum Becky
Published: November 2015

The dementia syndrome is characterized by cognitive and behavioral deficits that affect daily life functioning, including communication. Speech-language pathologists (SLPs) will see increased numbers of adults with dementia in the coming years, as the incidence and prevalence of diseases that cause dementia continue to grow. In this article, the authors provide an update on the syndrome of dementia and its most common cause, Alzheimer's disease. A framework for interventions is provided, along with a discussion of research evidence for specific treatment techniques. The article concludes with case studies of person-centered assessment and intervention for individuals with mild and moderate dementia severity.
Distributed adaptive containment control of heterogeneous linear multi‐agent systems: an output regulation approach
Authors: Chu Hongjun , Gao Lixin , Zhang Weidong
Published: November 2015

Output regulation is a general framework, for it not only can achieve closed‐loop stability, but also can realise asymptotic tracking and disturbance rejection. Within this framework, the authors consider the containment problem of heterogeneous linear multi‐agent systems with directed graphs. Via dynamic compensator techniques, the containment problem can be converted into cooperative output regulation problem. Moreover, they artfully construct regulation equations, whose solutions are also given. Adaptive protocols are proposed here by assigning a time‐varying coupling weight to each node. Unlike most existing protocols that depend on certain global information, protocols presented in this paper are independent of any global information, and hence are fully distributed. By combining the compensator technique with adaptive control, they propose the distributed dynamic adaptive state feedback and adaptive output feedback protocols for driving followers into the moving convex hull spanned by leaders. The obtained results are applied to the containment control of a network of heterogeneous agents, where the followers are described by mass‐damper spring systems, and the leaders are specified by harmonic oscillators.
High‐dynamic range image generation from single low‐dynamic range image
Authors: Huo Yongqing , Yang Fan
Published: November 2015

Due to the growing popularity of high‐dynamic range (HDR) image and the high complexity to capture HDR image, researchers focus on converting low‐dynamic range (LDR) content to HDR, which gives rise to a number of dynamic range expansion methods. Most of the existing methods try their best to tackle highlight areas during the expanding, however, in some cases, they cannot achieve approving results. In this study, a novel LDR image expansion technique is presented. The technique first detects the highlight areas in image; then preprocesses them and reconstructs the information of these regions; finally, expands the LDR image to HDR. Unlike the existing schemes, the proposed approach escapes the complicated treatment to highlight areas in the process of expansion, which makes the expansion straightforward; at the same time, it facilitates the expansion scheme and minimises the formation of the artefacts. The experimental results show that the proposed method performs well; the tone mapped versions of the produced HDR images are popular. The results of the image quality metric also illustrate that the novel approach can recover more image details with minimised contrast loss and reversal, compared with the existing schemes considered in the comparison.
Speckle reduction method for thyroid ultrasound images in neutrosophic domain
Authors: Koundal Deepika , Gupta Savita , Singh Sukhwinder
Published: November 2015

Neutrosophy is a useful tool for handling uncertainty associated with the images and widely used in image denoising. Speckle noise is inherent in ultrasound images, which generally tends to reduce resolution and contrast, thereby degrading the diagnostic accuracy. This paper presents a variational method based on Gamma distribution in the neutrosophic domain to improve clinical diagnosis and to enhance quality of ultrasound images. In this method, image is transformed into the neutrosophic (NS) domain via three membership subsets (true, indeterminate and false). Then, the filtering operation is applied based on total variation regularisation to reduce the indeterminacy of the image, which is measured by the entropy of an indeterminate set. The proposed speckle reduction method has been assessed on both the artificial speckle simulated images and real US images. The experimental results reveal the superiority of the proposed method in terms of both quantitatively and qualitatively as compared to other speckle reduction methods reported in the literature. Furthermore, the visual evaluation of despeckled images demonstrates that the proposed method suppresses the speckle noise as well as preserves the textures and fine details.
3D Ultrasound Evaluation of the Fetal Ear – Comparison of an xMatrix Probe with a Conventional Mechanical Probe
Authors: Bürkel Kai , Krämer Ursula , Möllers Mareike , Falkenberg Maria , Klockenbusch Walter , Schmitz Ralf
Published: November 2015

Purpose New 3 D technologies like xMatrix probes promise superiority over conventional mechanical probes and may allow a more detailed and time-saving prenatal diagnosis. In a comparison study we evaluate fetal ears. The aim of our study was to compare the following aspects of both techniques: (1) ultrasound detail resolution, (2) raw data acquisition time (AT) and (3) influence of covariates.

Materials and Methods 3 D raw data volumes of the fetal ear were collected with the V6 – 2 (V6) and with the xMatrix (X6) probe and were stored after offline customization to a single picture. Two observers scored these images independently. Furthermore, the 3 D raw data acquisition time (AT) was recorded. Concordance between observers, maternal age, body mass index (BMI), weeks of gestation and location of the placenta were evaluated.

Results Data volumes of 103 patients were analyzed. The X6 detected anatomic structures like the scapha (p = 0.0146), fossa triangularis (p = 0.0075) and cymba conchae (p = 0.0025) more often. The mean AT of the X6 was shorter compared to the V6 (p < 0.0001). A placenta location in the scanning field increased the AT only for the V6 (p < 0.01). Concordance between observers was higher for the X6 in most cases. Detailed structures were less visible at the end of pregnancy for both devices.

Conclusion The comparison study demonstrated clear advantages of the new xMatrix technology concerning an advanced and fast examination of detailed structures like the fetal ear. The importance of 3 D assessment in cases of fetal ear anomaly should be proven in further studies.
3.2.1 Cytochrome P450 in the Oxidation of Alkanes
Authors: Nolte J. , Urlacher V.
Published: November 2015

Selective direct oxidation of relatively cheap alkanes leads to valuable synthons that can be used as building blocks for the chemical and pharmaceutical industry. This chapter describes the hydroxylation of alkanes and fatty acids catalyzed by cytochrome P450 monooxygenases (CYP). It summarizes early and more-recent methods for the selective production of terminal and subterminal alcohols, dicarboxylic acids, and other oxidation products of alkanes using isolated enzymes and whole-cell biocatalysts.
3.3.2 Oxidation Using Laccases
Authors: Herter S. , Turner N. J.
Published: November 2015

The oxidation of a diverse range of primary and secondary alcohols to aldehydes and ketones, respectively, can be achieved via the laccase–mediator approach, which operates in aqueous or biphasic systems under mild conditions in the presence of oxygen.
3.4 Baeyer–Villiger Oxidation
Authors: de Gonzalo Calvo G. , van Berkel W. J.H. , Fraaije M. W.
Published: November 2015

This chapter describes methods for performing biocatalytic Baeyer–Villiger oxidations in which the final compounds are obtained under mild reaction conditions. In particular, reactions that can be performed with typical Baeyer–Villiger monooxygenases are presented that illustrate the high degree of regio- and/or enantioselectivity and good yields obtained with such enzymes for the synthesis of various compounds with high added value.
3.5.1 C—N Oxidation with Amine Oxidases and Amino Acid Oxidases
Authors: Pollegioni L. , Molla G.
Published: November 2015

Selective oxidation of amines and amino acids is of utmost importance in synthetic routes toward valuable chemicals. Such reactions can be performed using various enzymes. Here, the focus is on the use of the flavoenzymes monoamine oxidases and amino acid oxidases in the selective oxidation of natural and nonnatural amines and amino acids under mild reaction conditions. A number of recent successful applications, frequently based on protein-engineering studies, are reported.
3.10 Emerging Enzymes
Authors: Glueck S. , Hammer S. , Hauer B. , Nestl B.
Published: November 2015

Nature has developed and adapted a large number of enzyme types. Remarkably, these enzymes may be further used in biocatalysis for synthetic purposes. This chapter provides an overview of emerging cases of novel enzymes. Herein, nitrile reductases, sulfatases, squalene hopene cyclases, and aldoxime dehydratases may provide very powerful novel synthetic approaches in the futures, as they catalyze chemically interesting reactions under very mild reaction conditions and with high selectivities. These biocatalysts comprise a broad field of options, whereby biocatalysis may contribute to the quest for novel chemistry for future applications.
3.11 Creation and Optimization of Artificial Enzymes for Abiological Reactions
Authors: Obexer R. , Garrabou X. , Hilvert D.
Published: November 2015

Catalytic antibody technology and computational design represent conceptually distinct strategies to artificial enzymes. Both approaches provide significant activities and tailored specificities for mechanistically distinct transformations, including abiological and asymmetric reactions. This review compares the relative strengths and limitations of such de novo catalysts, delineating challenges to overcome in the pursuit of synthetically useful enzymes for any given chemical transformation.
Strategy and sustainability: a strategic logic for engagement with the environment
Authors: Rosenberg Mike
Published: November 2015

While many firms today routinely publish sustainability reports, work to increase their energy efficiency and market some part of their products or services to customers who are in some way interested in their environmental performance, there still appears to be a general lack of engagement on the issue of the environment from Chief Executive Officers and members of Boards of Directors. Despite years of effort and thousands of scholarly articles, academia has yet to develop a compelling framework with which to engage Senior Management. The article proposes such a framework based on an idea called environmental sensibility and the degree of compliance a firm chooses to pursue.
An efficient and stable hybrid extended Lagrangian/self-consistent field scheme for solving classical mutual induction
Authors: Albaugh Alex , Demerdash Omar , Head-Gordon Teresa
Published: November 2015

We have adapted a hybrid extended Lagrangian self-consistent field (EL/SCF) approach, developed for time reversible Born Oppenheimer molecular dynamics for quantum electronic degrees of freedom, to the problem of classical polarization. In this context, the initial guess for the mutual induction calculation is treated by auxiliary induced dipole variables evolved via a time-reversible velocity Verlet scheme. However, we find numerical instability, which is manifested as an accumulation in the auxiliary velocity variables, that in turn results in an unacceptable increase in the number of SCF cycles to meet even loose convergence tolerances for the real induced dipoles over the course of a 1 ns trajectory of the AMOEBA14 water model. By diagnosing the numerical instability as a problem of resonances that corrupt the dynamics, we introduce a simple thermostating scheme, illustrated using Berendsen weak coupling and Nose-Hoover chain thermostats, applied to the auxiliary dipole velocities. We find that the inertial EL/SCF (iEL/SCF) method provides superior energy conservation with less stringent convergence thresholds and a correspondingly small number of SCF cycles, to reproduce all properties of the polarization model in the NVT and NVE ensembles accurately. Our iEL/SCF approach is a clear improvement over standard SCF approaches to classical mutual induction calculations and would be worth investigating for application to ab initio molecular dynamics as well.
Characterization of electronic structure of periodically strained graphene
Authors: Aslani Marjan , Garner C. Michael , Kumar Suhas , Nordlund Dennis , Pianetta Piero , Nishi Yoshio
Published: November 2015

We induced periodic biaxial tensile strain in polycrystalline graphene by wrapping it over a substrate with repeating pillar-like structures with a periodicity of 600 nm. Using Raman spectroscopy, we determined to have introduced biaxial strains in graphene in the range of 0.4% to 0.7%. Its band structure was characterized using photoemission from valance bands, shifts in the secondary electron emission, and x-ray absorption from the carbon 1s levels to the unoccupied graphene conduction bands. It was observed that relative to unstrained graphene, strained graphene had a higher work function and higher density of states in the valence and conduction bands. We measured the conductivity of the strained and unstrained graphene in response to a gate voltage and correlated the changes in their behavior to the changes in the electronic structure. From these sets of data, we propose a simple band diagram representing graphene with periodic biaxial strain.
Exponential vanishing of the ground-state gap of the quantum random energy model via adiabatic quantum computing
Authors: Adame J. , Warzel S.
Published: November 2015

In this note, we use ideas of Farhi et al. [Int. J. Quantum. Inf. 6, 503 (2008) and Quantum Inf. Comput. 11, 840 (2011)] who link a lower bound on the run time of their quantum adiabatic search algorithm to an upper bound on the energy gap above the ground-state of the generators of this algorithm. We apply these ideas to the quantum random energy model (QREM). Our main result is a simple proof of the conjectured exponential vanishing of the energy gap of the QREM.
Magnetoelectric coupling and overall properties of multiferroic composites with 0-0 and 1-1 connectivity
Authors: Wang Yang , Weng George J.
Published: November 2015

Magnetoelectric coupling in a multiferroic composite consisting of piezoelectric and piezomagnetic phases with 0-0 and 1-1 connectivity is not a commonly studied subject. Unlike 0-3, 1-3, and 2-2 connectivity, both constituent phases now exist on equal geometrical footing and the computational process to the solution of the effective properties is highly nonlinear. In this article we develop a micro-continuum theory to examine the magnetoelectric coupling coefficients, α33 and α11, for these two types of connectivity, and compare the results with the more commonly studied 0-3 and 1-3 composites. With the BaTiO3-CoFe2O4 (BTO-CFO) system, our study reveals that, with 0-0 connectivity, its α33 and α11 are substantially higher than those of 0-3 connectivity over a wide range of phase concentration, but that, with 1-1 connectivity, its α33 is only comparable to that of the 1-3 composite whereas its α11 is higher only within the range of 0.4–0.65 CFO vol. %. We have also calculated the remaining 15 independent material constants of the transversely isotropic multiferroic composite, including the 2 electric, 2 magnetic, 3 piezoelectric, 3 piezomagnetic, and 5 elastic constants, and found that most of these constants lie between those of the 0-3 and 1-3 composites with the CFO-in-BTO and BTO-in-CFO configurations. The influence of an imperfect interface is also studied for all 17 constants, with results found to be lower for most cases. These remarkable features signify the importance of phase connectivity and interface condition on magnetoelectric coupling and overall properties of a multiferroic composite.
DNA terminal base pairs have weaker hydrogen bonds especially for AT under low salt concentration
Authors: Ferreira Izabela , Amarante Tauanne D. , Weber Gerald
Published: November 2015

DNA base pairs are known to open more easily at the helix terminal, a process usually called end fraying, the details of which are still poorly understood. Here, we present a mesoscopic model calculation based on available experimental data where we consider separately the terminal base pairs of a DNA duplex. Our results show an important reduction of hydrogen bond strength for terminal cytosine-guanine (CG) base pairs which is uniform over the whole range of salt concentrations, while for AT base pairs, we obtain a nearly 1/3 reduction but only at low salt concentrations. At higher salt concentrations, terminal adenine-thymine (AT) pair has almost the same hydrogen bond strength than interior bases. The calculated terminal stacking interaction parameters display some peculiarly contrasting behavior. While there is mostly no perceptible difference to internal stacking, for some cases, we observe an unusually strong dependence with salt concentration which does not appear follow any pattern or trend.
Laser spectroscopy of the Ã2Σ+−X̃2Πi band system of l-SiC3H
Authors: Umeki Hiroya , Nakajima Masakazu , Endo Yasuki
Published: November 2015

The Ã2Σ+−X̃2Πi band system of l-SiC3H in the region 14 700–16 300 cm−1 was re-investigated by laser induced fluorescence (LIF) and fluorescence depletion spectroscopy. Rotational analyses were made for three intense bands 000, 401, and 601701 by observing high-resolution LIF excitation spectra. The determined rotational constants demonstrate that SiC3H is linear in the Ã state, as is the case in the X̃ state, and the observed band types are consistent with the vibrational assignments. The ν3″ (C1–C2 stretch) level was identified in a newly observed dispersed fluorescence spectrum from the zero-vibrational level of the Ã state.
Hohenberg-Kohn theorems in electrostatic and uniform magnetostatic fields
Authors: Pan Xiao-Yin , Sahni Viraht
Published: November 2015

The Hohenberg-Kohn (HK) theorems of bijectivity between the external scalar potential and the gauge invariant nondegenerate ground state density, and the consequent Euler variational principle for the density, are proved for arbitrary electrostatic field and the constraint of fixed electron number. The HK theorems are generalized for spinless electrons to the added presence of an external uniform magnetostatic field by introducing the new constraint of fixed canonical orbital angular momentum. Thereby, a bijective relationship between the external scalar and vector potentials, and the gauge invariant nondegenerate ground state density and physical current density, is proved. A corresponding Euler variational principle in terms of these densities is also developed. These theorems are further generalized to electrons with spin by imposing the added constraint of fixed canonical orbital and spin angular momenta. The proofs differ from the original HK proof and explicitly account for the many-to-one relationship between the potentials and the nondegenerate ground state wave function. A Percus-Levy-Lieb constrained-search proof expanding the domain of validity to N-representable functions, and to degenerate states, again for fixed electron number and angular momentum, is also provided.
Quantification of protein interaction kinetics in a micro droplet
Authors: Yin L. L. , Wang S. P. , Shan X. N. , Zhang S. T. , Tao N. J.
Published: November 2015

Characterization of protein interactions is essential to the discovery of disease biomarkers, the development of diagnostic assays, and the screening for therapeutic drugs. Conventional flow-through kinetic measurements need relative large amount of sample that is not feasible for precious protein samples. We report a novel method to measure protein interaction kinetics in a single droplet with sub microliter or less volume. A droplet in a humidity-controlled environmental chamber is replacing the microfluidic channels as the reactor for the protein interaction. The binding process is monitored by a surface plasmon resonance imaging (SPRi) system. Association curves are obtained from the average SPR image intensity in the center area of the droplet. The washing step required by conventional flow-through SPR method is eliminated in the droplet method. The association and dissociation rate constants and binding affinity of an antigen-antibody interaction are obtained by global fitting of association curves at different concentrations. The result obtained by this method is accurate as validated by conventional flow-through SPR system. This droplet-based method not only allows kinetic studies for proteins with limited supply but also opens the door for high-throughput protein interaction study in a droplet-based microarray format that enables measurement of many to many interactions on a single chip.
Hybrid polaritons in a resonant inorganic/organic semiconductor microcavity
Authors: Höfner M. , Sadofev S. , Kobin B. , Hecht S. , Henneberger F.
Published: November 2015

We demonstrated the strong coupling regime in a hybrid inorganic-organic microcavity consisting of (Zn,Mg)O quantum wells and ladder-type oligo(p-phenylene) molecules embedded in a polymer matrix. A Fabry-Pérot cavity is formed by an epitaxially grown lower ZnMgO Bragg reflector and a dielectric mirror deposited atop of the organic layer. A clear anticrossing behavior of the polariton branches related to the Wannier-Mott and Frenkel excitons, and the cavity photon mode with a Rabi-splitting reaching 50 meV, is clearly identified by angular-dependent reflectivity measurements at low temperature. By tailoring the structural design, an equal mixing with weights of about 0.3 for all three resonances is achieved for the middle polariton branch at an incidence angle of about 35°.
A 128-channel picoammeter system and its application on charged particle beam current distribution measurements
Authors: Yu Deyang , Liu Junliang , Xue Yingli , Zhang Mingwu , Cai Xiaohong , Hu Jianjun , Dong Jinmei , Li Xin
Published: November 2015

A 128-channel picoammeter system is constructed based on instrumentation amplifiers. Taking advantage of a high electric potential and narrow bandwidth in DC energetic charged beam measurements, a current resolution better than 5 fA can be achieved. Two sets of 128-channel strip electrodes are implemented on printed circuit boards and are employed for ion and electron beam current distribution measurements. Tests with 60 keV O3+ ions and 2 keV electrons show that it can provide exact boundaries when a positive charged particle beam current distribution is measured.
Oxygen pump based on stabilized zirconia
Authors: Zhang Xiao-Dong , Li Jian-Jun , Guo Xin
Published: November 2015

When a DC voltage is applied across a zirconia ceramic layer, an electrical field is established to drive oxygen species through the layer. Taking advantage of this electrochemical phenomenon, we have designed and developed an oxygen pump that offers continuously adjustable oxygen partial pressure from 1 bar down to 10−24 bar in the temperature range of 650–1100 °C. Demonstrated with electrical conductivity measurements on Fe-doped SrTiO3, these excellent capabilities of the oxygen pump are valuable for investigations on the defect chemistry of electroceramics.
Sign reversal of transformation entropy change in Co2Cr(Ga,Si) shape memory alloys
Authors: Xu Xiao , Omori Toshihiro , Nagasako Makoto , Kanomata Takeshi , Kainuma Ryosuke
Published: November 2015

In situ X-ray diffraction (XRD) measurements and compression tests were performed on Co2Cr(Ga,Si) shape memory alloys. The reentrant martensitic transformation behavior was directly observed during the in situ XRD measurements. The high-temperature parent phase and low-temperature reentrant parent phase were found to have a continuous temperature dependence of lattice parameter, therefore suggesting that they are the same phase in nature. Moreover, compression tests were performed on a parent-phase single crystal sample; an evolution from normal to inverse temperature dependence of critical stress for martensitic transformation was directly observed. Based on the Clausius-Clapeyron analysis, a sign reversal of entropy change can be expected on the same alloy.
Structure of a zinc oxide ultra-thin film on Rh(100)
Authors: Yuhara J. , Kato D. , Matsui T. , Mizuno S.
Published: November 2015

The structural parameters of ultra-thin zinc oxide films on Rh(100) are investigated using low-energy electron diffraction intensity (LEED I–V) curves, scanning tunneling microscopy (STM), and first-principles density functional theory (DFT) calculations. From the analysis of LEED I–V curves and DFT calculations, two optimized models A and B are determined. Their structures are basically similar to the planer h-BN ZnO(0001) structure, although some oxygen atoms protrude from the surface, associated with an in-plane shift of Zn atoms. From a comparison of experimental STM images and simulated STM images, majority and minority structures observed in the STM images represent the two optimized models A and B, respectively.
Magnetohydrodynamic waves with relativistic electrons and positrons in degenerate spin-1/2 astrophysical plasmas
Authors: Maroof R. , Ali S. , Mushtaq A. , Qamar A.
Published: November 2015

Linear properties of high and low frequency waves are studied in an electron-positron-ion (e-p-i) dense plasma with spin and relativity effects. In a low frequency regime, the magnetohydrodynamic (MHD) waves, namely, the magnetoacoustic and Alfven waves are presented in a magnetized plasma, in which the inertial ions are taken as spinless and non-degenerate, whereas the electrons and positrons are treated quantum mechanically due to their smaller mass. Quantum corrections associated with the spin magnetization and density correlations for electrons and positrons are re-considered and a generalized dispersion relation for the low frequency MHD waves is derived to account for relativistic degeneracy effects. On the basis of angles of propagation, the dispersion relations of different modes are discussed analytically in a degenerate relativistic plasma. Numerical results reveal that electron and positron relativistic degeneracy effects significantly modify the dispersive properties of MHD waves. Our present analysis should be useful for understanding the collective interactions in dense astrophysical compact objects, like, the white dwarfs and in atmosphere of neutron stars.
Nonlinear spreading of Farley-Buneman waves
Authors: Litt S. K. , Bains A. S. , Smolyakov A. I. , Onishchenko O. G. , Pokhotelov O. A.
Published: November 2015

Nonlinear coupling of Farley-Buneman (FB) waves is studied using the method of modulational decay instabilities. Dispersion relation for the growth of the secondary Farley-Buneman waves has been derived. It is shown that the primary wave is unstable with respect to the modulational instability decay, producing the secondary waves with a finite flow angle with respect to the direction of the electron E×B flow. This process leads to the nonlinear spreading of the primary FB waves into the linearly stable region which is consistent with the previous numerical simulations and some observations.
Experimental study of subcritical laboratory magnetized collisionless shocks using a laser-driven magnetic piston
Authors: Schaeffer D. B. , Everson E. T. , Bondarenko A. S. , Clark S. E. , Constantin C. G. , Winske D. , Gekelman W. , Niemann C.
Published: November 2015

Recent experiments at the University of California, Los Angeles have successfully generated subcritical magnetized collisionless shocks, allowing new laboratory studies of shock formation relevant to space shocks. The characteristics of these shocks are compared with new data in which no shock or a pre-shock formed. The results are consistent with theory and 2D hybrid simulations and indicate that the observed shock or shock-like structures can be organized into distinct regimes by coupling strength. With additional experiments on the early time parameters of the laser plasma utilizing Thomson scattering, spectroscopy, and fast-gate filtered imaging, these regimes are found to be in good agreement with theoretical shock formation criteria.
Effective group index of refraction in non-thermal plasma photonic crystals
Authors: Mousavi A. , Sadegzadeh S.
Published: November 2015

Plasma photonic crystals (PPCs) are periodic arrays that consist of alternate layers of micro-plasma and dielectric. These structures are used to control the propagation of electromagnetic waves. This paper presents a survey of research on the effect of non-thermal plasma with bi-Maxwellian distribution function on one dimensional PPC. A plasma with temperature anisotropy is not in thermodynamic equilibrium and can be described by the bi-Maxwellian distribution function. By using Kronig-Penny's model, the dispersion relation of electromagnetic modes in one dimensional non-thermal PPC (NPPC) is derived. The band structure, group velocity vg, and effective group index of refraction neff(g) of such NPPC structure with TeO2 as the material of dielectric layers have been studied. The concept of negative group velocity and negative neff(g), which indicates an anomalous behaviour of the PPCs, are also observed in the NPPC structures. Our numerical results provide confirmatory evidence that unlike PPCs there are finite group velocity and non-zero effective group indexes of refraction in photonic band gaps (PBGs) that lie in certain ranges of normalized frequency. In other words, inside the PBGs of NPPCs, neff(g) becomes non-zero and photons travel with a finite group velocity. In this special case, this velocity varies alternately between 20c and negative values of the order 103c (c is the speed of light in vacuum).
Photoelectron emission from metal surfaces induced by radiation emitted by a 14 GHz electron cyclotron resonance ion source
Authors: Laulainen Janne , Kalvas Taneli , Koivisto Hannu , Komppula Jani , Kronholm Risto , Tarvainen Olli
Published: November 2015

Photoelectron emission measurements have been performed using a room-temperature 14 GHz ECR ion source. It is shown that the photoelectron emission from Al, Cu, and stainless steel (SAE 304) surfaces, which are common plasma chamber materials, is predominantly caused by radiation emitted from plasma with energies between 8 eV and 1 keV. Characteristic X-ray emission and bremsstrahlung from plasma have a negligible contribution to the photoelectron emission. It is estimated from the measured data that the maximum conceivable photoelectron flux from plasma chamber walls is on the order of 10% of the estimated total electron losses from the plasma.
Study of electron current extraction from a radio frequency plasma cathode designed as a neutralizer for ion source applications
Authors: Jahanbakhsh Sina , Satir Mert , Celik Murat
Published: November 2015

Plasma cathodes are insert free devices that are developed to be employed as electron sources in electric propulsion and ion source applications as practical alternatives to more commonly used hollow cathodes. Inductively coupled plasma cathodes, or Radio Frequency (RF) plasma cathodes, are introduced in recent years. Because of its compact geometry, and simple and efficient plasma generation, RF plasma source is considered to be suitable for plasma cathode applications. In this study, numerous RF plasma cathodes have been designed and manufactured. Experimental measurements have been conducted to study the effects of geometric and operational parameters. Experimental results of this study show that the plasma generation and electron extraction characteristics of the RF plasma cathode device strongly depend on the geometric parameters such as chamber diameter, chamber length, orifice diameter, orifice length, as well as the operational parameters such as RF power and gas mass flow rate.
Point contacts in encapsulated graphene
Authors: Handschin Clevin , Fülöp Bálint , Makk Péter , Blanter Sofya , Weiss Markus , Watanabe Kenji , Taniguchi Takashi , Csonka Szabolcs , Schönenberger Christian
Published: November 2015

We present a method to establish inner point contacts with dimensions as small as 100 nm on hexagonal boron nitride (hBN) encapsulated graphene heterostructures by pre-patterning the top-hBN in a separate step prior to dry-stacking. 2- and 4-terminal field effect measurements between different lead combinations are in qualitative agreement with an electrostatic model assuming point-like contacts. The measured contact resistances are 0.5–1.5 kΩ per contact, which is quite low for such small contacts. By applying a perpendicular magnetic field, an insulating behaviour in the quantum Hall regime was observed, as expected for inner contacts. The fabricated contacts are compatible with high mobility graphene structures and open up the field for the realization of several electron optical proposals.
Fast response of electron-scale turbulence to auxiliary heating cessation in National Spherical Torus Experiment
Authors: Ren Y. , Wang W. X. , LeBlanc B. P. , Guttenfelder W. , Kaye S. M. , Ethier S. , Mazzucato E. , Lee K. C. , Domier C. W. , Bell R. , Smith D. R. , Yuh H.
Published: November 2015

In this letter, we report the first observation of the fast response of electron-scale turbulence to auxiliary heating cessation in National Spherical Torus eXperiment [Ono et al., Nucl. Fusion 40, 557 (2000)]. The observation was made in a set of RF-heated L-mode plasmas with toroidal magnetic field of 0.55 T and plasma current of 300 kA. It is observed that electron-scale turbulence spectral power (measured with a high-k collective microwave scattering system) decreases significantly following fast cessation of RF heating that occurs in less than 200 μs. The large drop in the turbulence spectral power has a short time delay of about 1–2 ms relative to the RF cessation and happens on a time scale of 0.5–1 ms, much smaller than the energy confinement time of about 10 ms. Power balance analysis shows a factor of about 2 decrease in electron thermal diffusivity after the sudden drop of turbulence spectral power. Measured small changes in equilibrium profiles across the RF cessation are unlikely able to explain this sudden reduction in the measured turbulence and decrease in electron thermal transport, supported by local linear stability analysis and both local and global nonlinear gyrokinetic simulations. The observations imply that nonlocal flux-driven mechanism may be important for the observed turbulence and electron thermal transport.
Femtosecond laser pulse train interaction with dielectric materials
Authors: Dematteo Caulier O. , Mishchik K. , Chimier B. , Skupin S. , Bourgeade A. , Javaux Léger C. , Kling R. , Hönninger C. , Lopez J. , Tikhonchuk V. , Duchateau G.
Published: November 2015

The interaction of trains of femtosecond microjoule laser pulses with dielectric materials by means of a multi-scale model is investigated. Theoretical predictions are directly confronted with experimental observations in soda-lime glass. It is shown that due to the low heat conductivity, a significant fraction of the laser energy can be accumulated in the absorption region. Depending on the pulse repetition rate, the material can be heated to high temperatures even though the single pulse energy is too low to induce a significant material modification. Regions heated above the glass transition temperature in the simulations correspond very well to zones of permanent material modifications observed in the experiments. It turns out that pulse-to-pulse variations of the laser absorption are negligible and of minor influence to permanent material modifications.
Antiferromagnetic order competing with topological state in CexBi2−xTe3
Authors: Lee H. S. , Kim J. , Lee K. , Jelen A. , Vrtnik S. , Jagličić Z. , Dolinšek J. , Jung M. H.
Published: November 2015

The topological surface states in three-dimensional topological insulators are easily tuned by chemical doping, especially by magnetic impurities. We prepared single crystals of CexBi2−xTe3 with various x (=0.04, 0.06, 0.08, 0.10, and 0.12). The obtained crystals were characterized by X-ray diffraction and scanning electron microscopy. The magnetic susceptibility data revealed that the Ce atoms are well substituted for Bi into Bi2Te3. From the Curie-Weiss fits, we observed that the effective magnetic moments μeff are close to 2.54 μB for free Ce ion, and the paramagnetic Curie-Weiss temperatures θp are negatively increased from 2.87 K to −59.3 K with increasing x. The magnetization data clearly showed antiferromagnetic orders around TN = 4.1 K for x ≥ 0.08, where θp suddenly increases, and the electrical resistivity is simply metallic and the magnetoresistance is parabolic. Only for x = 0.06, exotic physical properties arising from the topological states were observed such as non-metallic behavior in the electrical resistivity and linear dependence of the magnetoresistance. Moreover, the carrier concentration of x = 0.06 is one order lower than that of x ≥ 0.08. These observations propose that the antiferromagnetic order is strongly competing with the topological state in CexBi2−xTe3.