bluuebunny/crossref_metadata_2025 huggingface dataset:
Gait Disturbances in Patients With Stroke
Authors: Balaban Birol , Tok Fatih
Published: January 2014

Poststroke hemiplegic gait is a mixture of deviations and compensatory motion dictated by residual functions, and thus each patient must be examined and his/her unique gait pattern identified and documented. Quantitative 3‐dimensional gait analysis is the best way to understand the complex multifactorial gait dysfunction in hemiparetic patients. The goals of the present work are to (1) review the temporospatial, kinematic, kinetic, and electromyographic deviations from normal gait that commonly occur after stroke and are of clinical significance, along with the most likely causes of these deviations, and (2) differentiate the departures from normal gait parameters that arise as a direct consequence of poststroke motor problems and those that arise as learned or adaptive compensations for poststroke motor problems.
Life Care Planning: A Natural Domain of Physiatry
Authors: Gonzales Joe G. , Zotovas Andrea
Published: January 2014

This article is an introduction to life care planning and its relevance to physiatry and physiatric practice. It includes a discussion of life care planning, physiatry's role within its history and evolution, and life care planning methodologies. It also discusses life care planning education and certification, how the core competencies of the physiatrist are particularly relevant and applicable to life care planning, and life care planning's capacity to complement and diversify a clinical physiatric practice.
Advances in molecular biomarkers for gastric cancer: miRNAs as emerging novel cancer markers
Authors: Wu Hua-Hsi , Lin Wen-chang , Tsai Kuo-Wang
Published: January 2014

Carcinoma of the stomach is one of the most prevalent cancer types in the world. Although the incidence of gastric cancer is declining, the outcomes of gastric cancer patients remain dismal because of the lack of effective biomarkers to detect early gastric cancer. Modern biomedical research has explored many potential gastric cancer biomarker genes by utilising serum protein antigens, oncogenic genes or gene families through improving molecular biological technologies, such as microarray, RNA-Seq and the like. Recently, the small noncoding microRNAs (miRNAs) have been suggested to be critical regulators in the oncogenesis pathways and to serve as useful clinical biomarkers. This new class of biomarkers is emerging as a novel molecule for cancer diagnosis and prognosis, including gastric cancer. By translational suppression of target genes, miRNAs play a significant role in the gastric cancer cell physiology and tumour progression. There are potential implications of previously discovered gastric cancer molecular biomarkers and their expression modulations by respective miRNAs. Therefore, many miRNAs are found to play oncogenic roles or tumour-suppressing functions in human cancers. With the surprising stability of miRNAs in tissues, serum or other body fluids, miRNAs have emerged as a new type of cancer biomarker with immeasurable clinical potential.
The global burden of anxiety disorders in 2010
Authors: Baxter A. J. , Vos T. , Scott K. M. , Ferrari A. J. , Whiteford H. A.
Published: January 2014

Background

Despite their high prevalence, the global burden of anxiety disorders has never been calculated comprehensively. The new Global Burden of Disease (GBD) study has estimated burden due to morbidity and mortality caused by any anxiety disorder.

Method

Prevalence was estimated using Bayesian meta-regression informed by data identified in a systematic review. Years of life lived with disability (YLDs) were calculated by multiplying prevalent cases by an average disability weight based on severity proportions (mild, moderate and severe). Disability-adjusted life years (DALYs) were then calculated and age standardized using global standard population figures. Estimates were also made for additional suicide mortality attributable to anxiety disorders. Findings are presented for YLDs, DALYs and attributable burden due to suicide for 21 world regions in 1990 and 2010.

Results

Anxiety disorders were the sixth leading cause of disability, in terms of YLDs, in both high-income (HI) and low- and middle-income (LMI) countries. Globally, anxiety disorders accounted for 390 DALYs per 100 000 persons [95% uncertainty interval (UI) 191–371 DALYs per 100 000] in 2010, with no discernible change observed over time. Females accounted for about 65% of the DALYs caused by anxiety disorders, with the highest burden in both males and females experienced by those aged between 15 and 34 years. Although there was regional variation in prevalence, the overlap between uncertainty estimates means that substantive differences in burden between populations could not be identified.

Conclusions

Anxiety disorders are chronic, disabling conditions that are distributed across the globe. Future estimates of burden could be further improved by obtaining more representative data on severity state proportions.
Dynamics of the IFMIF very high-intensity beam
Authors: Nghiem P.A.P. , Chauvin N. , Comunian M. , Delferrière O. , Duperrier R. , Mosnier A. , Oliver C. , Simeoni W. , Uriot D.
Published: January 2014

For the purpose of material studies for future nuclear fusion reactors, the IFMIF deuteron beams present a simultaneous combination of unprecedentedly high intensity (2 × 125 mA CW), power (2 × 5 MW) and space charge. Special considerations and new concepts have been developed in order to overcome these challenges. The global strategy for beam dynamics design of the 40 MeV IFMIF accelerators is presented, stressing on the control of micro-losses, and the possibility of online fine tuning. Start-to-end simulations without and with errors are presented for the prototype accelerator. Considerations about conflicts between halo and emittance minimization are then discussed in this very high space charge context.
Kinematic analysis of a single-loop reconfigurable 7R mechanism with multiple operation modes
Authors: He Xiuyun , Kong Xianwen , Chablat Damien , Caro Stéphane , Hao Guangbo
Published: January 2014

This paper presents a novel one-degree-of-freedom (1-DOF) single-loop reconfigurable 7R mechanism with multiple operation modes (SLR7RMMOM), composed of seven revolute (R) joints, via adding a revolute joint to the overconstrained Sarrus linkage. The SLR7RMMOM can switch from one operation mode to another without disconnection and reassembly, and is a non-overconstrained mechanism. The algorithm for the inverse kinematics of the serial 6R mechanism using kinematic mapping is adopted to deal with the kinematic analysis of the SLR7RMMOM. First, a numerical method is applied and an example is given to show that there are 13 sets of solutions for the SLR7RMMOM, corresponding to each input angle. Among these solutions, nine sets are real solutions, which are verified using both a computer-aided design (CAD) model and a prototype of the mechanism. Then an algebraic approach is also used to analyse the mechanism and same results are obtained as the numerical one. It is shown from both numerical and algebraic approaches that the SLR7RMMOM has three operation modes: a translational mode and two 1-DOF planar modes. The transitional configurations among the three modes are also identified.
IMPLEMENTATION OF EUNETHTA CORE MODEL® IN LOMBARDIA: THE VTS FRAMEWORK
Authors: Radaelli Giovanni , Lettieri Emanuele , Masella Cristina , Merlino Luca , Strada Alberto , Tringali Michele
Published: January 2014

Objectives:This study describes the health technology assessment (HTA) framework introduced by Regione Lombardia to regulate the introduction of new technologies. The study outlines the process and dimensions adopted to prioritize, assess and appraise the requests of new technologies.

Methods:The HTA framework incorporates and adapts elements from the EUnetHTA Core Model and the EVIDEM framework. It includes dimensions, topics, and issues provided by EUnetHTA Core Model to collect data and process the assessment. Decision making is instead supported by the criteria and Multi-Criteria Decision Analysis technique from the EVIDEM consortium.

Results:The HTA framework moves along three process stages: (i) prioritization of requests, (ii) assessment of prioritized technology, (iii) appraisal of technology in support of decision making. Requests received by Regione Lombardia are first prioritized according to their relevance along eight dimensions (e.g., costs, efficiency and efficacy, organizational impact, safety). Evidence about the impacts of the prioritized technologies is then collected following the issues and topics provided by EUnetHTA Core Model. Finally, the Multi-Criteria Decision Analysis technique is used to appraise the novel technology and support Regione Lombardia decision making.

Conclusions:The VTS (Valutazione delle Tecnologie Sanitarie) framework has been successfully implemented at the end of 2011. From its inception, twenty-six technologies have been processed.
Disaster Health After The 2011 Great East Japan Earthquake
Authors: Kako Mayumi , Arbon Paul , Mitani Satoko
Published: January 2014

Introduction

The March 11, 2011 disaster was unparalleled in the disaster history of Japan. There is still enormous effort required in order for Japan to recover from the damage, not only financially, but psychosocially. This paper is a review of the studies that have been undertaken since this disaster, from after the March 11th disaster in 2011 to the end of 2012, and will provide an overview of the disaster-health research literature published during this period.

Methods

The Japanese database Ichushi Ver. 5 was used to review the literature. This database is the most frequently used database in Japanese health-sciences research. The keywords used in the search were “Higashi Nihon Dai-shinsai” (The Great East Japan Earthquake).

Results

A total of 5,889 articles were found. Within this selection, 163 articles were categorized as original research (gencho ronbun). The articles were then sorted and the top four key categories were as follows: medicine (n = 98), mental health (n = 18), nursing (n = 13), and disaster management (n = 10). Additional categories were: nutrition (n = 4), public health (n = 3), radiology, preparedness, and pharmacology (n = 2 for each category). Nine articles appeared with only one category label and were grouped as “others.”

Conclusion

This review provides the current status of disaster-health research following the Great East Japan Earthquake. The research focus over the selected period was greatly directed towards medical considerations, especially vascular conditions and renal dialysis. Considering the compounding factors of the cold temperatures at the time of the disaster, the geography, the extensive dislocation of the population, and the demographics of an aging community, it is noteworthy that the immediate and acute impact of the March 11th disaster was substantial compared with other events and their studies on the impact of disaster on chronic and long-term illness. The complexity of damage caused by the earthquake event and the associated nuclear power plant event, which possibly affected people more psychologically than physically, might also need to be investigated with respect to long term objectives for improving disaster preparedness and management.

KakoM, ArbonP, MitaniS. Literature review on disaster health after the 2011 Great East Japan Earthquake. Prehosp Disaster Med. 2014;29(1):1-6.
Morphosyntactic knowledge of clitics by Portuguese heritage bilinguals
Authors: RINKE ESTHER , FLORES CRISTINA
Published: January 2014

This paper focuses on the linguistic competence of adult Portuguese–German bilinguals in their heritage language, European Portuguese (EP), which they acquired at home in early childhood in the context of German as the majority language. Based on a grammaticality judgment test, we investigate their morphosyntactic knowledge of clitics. The central questions are whether possible deviations from native monolinguals may be traced back to a) lack of contact with the formal register; b) reduced input after preschool age; and c) cross-linguistic influence. The results reveal qualitative differences between the heritage speakers and a group of monolingual controls in almost all test conditions. We conclude that although the linguistic knowledge of the heritage bilinguals investigated in this study differs from that of monolinguals, it is not “deficient” but “different” and “innovative”, because it is primarily based on the spoken variety of the language and because it promotes linguistic changes which are inherent in the speech of native monolinguals.
Forty-three-year-old woman with mediastinal PEComa treated with chemoradiation therapy
Authors: Sheu Tommy , Wilson Joella , Carpenter Larry Steven
Published: January 2014

The rarity of PEComa tumours has precluded any clinical trials, but surgery remains the most commonly reported treatment modality with just a few reports on treatment plans involving chemoradiation. We describe a patient with a mediastinal PEComa who presented with symptoms concerning for superior vena cava syndrome. She was deemed inoperable and was thus treated exclusively with chemoradiation therapy. The use of chemoradiation in the treatment of PEComa tumours is reviewed.
Flying beyond Gray's Anatomy: A psychologist's experience in palliative care and psycho-oncology
Authors: O'Brien Casey L.
Published: January 2014

A clinical fellowship provides opportunities for health professionals to learn specialist skills from experienced mentors in “real-world” environments. In 2010–2011, I had the opportunity to complete a palliative care and psycho-oncology clinical fellowship in a public hospital. I found ways to integrate academic training into my practice and become a more independent psychologist. In this essay, I aim to share my experience with others and highlight key learnings and challenges I encountered. In providing psychosocial care, I learned to adapt my psychological practice to a general hospital setting, learning about the medical concerns, and life stories of my patients. I faced challenges navigating referral processes and had opportunities to strengthen my psychotherapy training. In the fellowship, I engaged in educational activities from the more familiar psychological skills to observing surgical teams at work. I also developed confidence facilitating groups and an interest in group psychological support for young adult offspring of people with cancer. I was able to engage participants with haematological cancer in qualitative research about their experiences of corticosteroid treatment. In this process, I came to understand the complexity of chemotherapy regimens. Overseeing my development were multiple supervisors, offering unique insights that I could take in and integrate with my personal practice and worldview. Throughout this process I became increasingly tuned into my own process, the impact of the work, and developed self-care routines to help disconnect from my day. I also reflected on my experiences of loss and grief and developed a deeper understanding of myself as a person. I use the metaphor of a parachuting journey to illustrate various aspects of my learning.
ON FLATTENING ELIMINATION RULES
Authors: OLKHOVIKOV GRIGORY K. , SCHROEDER-HEISTER PETER
Published: January 2014

In proof-theoretic semantics of intuitionistic logic it is well known that elimination rules can be generated from introduction rules in a uniform way. If introduction rules discharge assumptions, the corresponding elimination rule is a rule of higher level, which allows one to discharge rules occurring as assumptions. In some cases, these uniformly generated elimination rules can be equivalently replaced with elimination rules that only discharge formulas or do not discharge any assumption at all—they can be flattened in a terminology proposed by Read. We show by an example from propositional logic that not all introduction rules have flat elimination rules. We translate the general form of flat elimination rules into a formula of second-order propositional logic and demonstrate that our example is not equivalent to any such formula. The proof uses elementary techniques from propositional logic and Kripke semantics.
Inserting Visions of Justice into a Contemporary History of International Law
Authors: SCOTT Shirley V.
Published: January 2014

The history of international law is often told in terms of the rise and fall of great powers or as a mechanism of colonial subjugation. To the extent that these accounts consider justice, it is usually to demonstrate its absence. This paper points out that justice has been integral to the evolution of international law in the era of the United States. Individuals and members of civil society in the US and Europe have influenced systemic developments in international law through their efforts to realize a vision of justice in interstate relations, their vision being of a body of international law and a world court which together obviate the need for war. To suggest the possibility of an historical narrative constructed around justice is not to deny the validity of other histories focused on inequitable relations of power, but to point to the scope for nuance in the frameworks within which we portray international law and its history.
Identifying Druggable Targets by Protein Microenvironments Matching: Application to Transcription Factors
Authors: Liu T , Altman RB
Published: January 2014

Druggability of a protein is its potential to be modulated by drug‐like molecules. It is important in the target selection phase. We hypothesize that: (i) known drug‐binding sites contain advantageous physicochemical properties for drug binding, or “druggable microenvironments” and (ii) given a target, the presence of multiple druggable microenvironments similar to those seen previously is associated with a high likelihood of druggability. We developed DrugFEATURE to quantify druggability by assessing the microenvironments in potential small‐molecule binding sites. We benchmarked DrugFEATURE using two data sets. One data set measures druggability using NMR‐based screening. DrugFEATURE correlates well with this metric. The second data set is based on historical drug discovery outcomes. Using the DrugFEATURE cutoffs derived from the first, we accurately discriminated druggable and difficult targets in the second. We further identified novel druggable transcription factors with implications for cancer therapy. DrugFEATURE provides useful insight for drug discovery, by evaluating druggability and suggesting specific regions for interacting with drug‐like molecules.

CPT Pharmacometrics Syst. Pharmacol. (2014) 3, e93; doi:10.1038/psp.2013.66; published online 22 January 2014
Spin memristive magnetic tunnel junctions with CoO-ZnO nano composite barrier
Authors: Li Qiang , Shen Ting-Ting , Cao Yan-Ling , Zhang Kun , Yan Shi-Shen , Tian Yu-Feng , Kang Shi-Shou , Zhao Ming-Wen , Dai You-Yong , Chen Yan-Xue , Liu Guo-Lei , Mei Liang-Mo , Wang Xiao-Lin , Grünberg Peter
Published: January 2014

The spin memristive devices combining memristance and tunneling magnetoresistance have promising applications in multibit nonvolatile data storage and artificial neuronal computing. However, it is a great challenge for simultaneous realization of large memristance and magnetoresistance in one nanoscale junction, because it is very hard to find a proper spacer layer which not only serves as good insulating layer for tunneling magnetoresistance but also easily switches between high and low resistance states under electrical field. Here we firstly propose to use nanon composite barrier layers of CoO-ZnO to fabricate the spin memristive Co/CoO-ZnO/Co magnetic tunnel junctions. The bipolar resistance switching ratio is high up to 90 and the TMR ratio of the high resistance state gets to 8% at room temperature, which leads to three resistance states. The bipolar resistance switching is explained by the metal-insulator transition of CoO1−v layer due to the migration of oxygen ions between CoO1−v and ZnO1−v.
Unexpected dehomologation of primary alcohols to one-carbon shorter carboxylic acids using o-iodoxybenzoic acid (IBX)
Authors: Xu Shu , Itto Kaori , Satoh Masahide , Arimoto Hirokazu
Published: January 2014

IBX affords a novel, highly selective dehomologation of alcohols to their corresponding one-carbon shorter carboxylic acids.
Effects of the preparation method on the performance of the Cu/ZnO/Al2O3catalyst for the manufacture ofl-phenylalaninol with high ee selectivity froml-phenylalanine methyl ester
Authors: Shi Zhangping , Xiao Xiuzhen , Mao Dongsen , Lu Guanzhong
Published: January 2014

Efficient catalytic hydrogenation ofl-phenylalanine methyl ester tol-phenylalaninol over the Cu/ZnO/Al2O3catalyst with ~100% ee selectivity.
Artificial metalloenzymes derived from bovine β-lactoglobulin for the asymmetric transfer hydrogenation of an aryl ketone – synthesis, characterization and catalytic activity
Authors: Chevalley Alice , Cherrier Mickael V. , Fontecilla-Camps Juan C. , Ghasemi Mahsa , Salmain Michèle
Published: January 2014

Protein hybrids resulting from the supramolecular anchoring to bovine β-lactoglobulin of fatty acid-derived Rh(iii) diimine complexes catalysed the asymmetric transfer hydrogenation of trifluoroacetophenone with up to 32% ee.
Structure and thermal expansion of the tungsten bronze Pb2KNb5O15
Authors: Lin Kun , Wu Hui , Wang Fangfang , Rong Yangchun , Chen Jun , Deng Jinxia , Yu Ranbo , Fang Liang , Huang Qingzhen , Xing Xianran
Published: January 2014

Negative thermal expansion and abnormal spontaneous polarization direction alongbaxis in tetragonal tungsten bronze Pb2KNb5O15are presented. A Pb–O covalency, octahedrons cooperative rotation mechanism is proposed.
Environmentally benign perfluorooctanesulfonate alternatives using a Zn/CuI mediated Michael-type addition in imidazolium ionic liquids
Authors: Vijaykumar B. V. D. , Premkumar B. , Jang Kiwan , Choi Bong-In , Falck J. R. , Sheldrake G. N. , Shin Dong-Soo
Published: January 2014

Michael-type addition in imidazolium ionic liquids for the synthesis of bio-degradable and efficient alternatives to perfluorooctanesulfonic acid.
Investigation and modelling of surface tension of power-law fluids
Authors: Muthamizhi K. , Kalaichelvi P. , Powar Shubhangi Tukaram , Jaishree R.
Published: January 2014

Thermo-physical properties of power-law fluids are required for engineering and product design applications in food, drugs, cosmetics and agriculture.
Structure and dynamics in an organic ionic plastic crystal, N-ethyl-N-methyl pyrrolidinium bis(trifluoromethanesulfonyl) amide, mixed with a sodium salt
Authors: Forsyth Maria , Chimdi Tarekegn , Seeber Aaron , Gunzelmann Daniel , Howlett Patrick C.
Published: January 2014

We present for the first time, the solid state phase behaviour of the organic ionic plastic crystal (OIPC) N-methyl-N-ethyl-pyrrolidinium bis(trifluoromethanesulfonyl)amide, [C2mpyr][NTf2], upon mixing with the sodium salt, Na[NTf2].
Network assembly of gold nanoparticles linked through fluorenyl dithiol bridges
Authors: Quintiliani Maurizio , Bassetti Mauro , Pasquini Chiara , Battocchio Chiara , Rossi Marco , Mura Francesco , Matassa Roberto , Fontana Laura , Russo Maria Vittoria , Fratoddi Ilaria
Published: January 2014

Gold nanoparticles stabilized by two novel bifunctional fluorenyl thiols, generated in situ from 9,9-didodecyl-2,7-bis(acetylthio)fluorene (1) and 9,9-didodecyl-2,7-bis(acetylthiophenylethynyl)fluorene (2), exhibit bridged structures which self-assemble in parallel lines.
1-Nitronyl nitroxide pyrene as a new off–on fluorescent chemosensor for Cu2+
Authors: Han Huifei , Wang Mian , Wang Hongmei
Published: January 2014

A highly selective and sensitive colorimetric chemosensor based on nitronyl nitroxide was developed for detection of Cu2+.
Biochemical and genetic characterization ofTrypanosoma cruzi N-myristoyltransferase
Authors: Roberts Adam J. , Torrie Leah S. , Wyllie Susan , Fairlamb Alan H.
Published: January 2014

Co- and post-translational N-myristoylation is known to play a role in the correct subcellular localization of specific proteins in eukaryotes. The enzyme that catalyses this reaction, NMT (N-myristoyltransferase), has been pharmacologically validated as a drug target in the African trypanosome, Trypanosoma brucei. In the present study, we evaluate NMT as a potential drug target in Trypanosoma cruzi, the causative agent of Chagas’ disease, using chemical and genetic approaches. Replacement of both allelic copies of TcNMT (T. cruzi NMT) was only possible in the presence of a constitutively expressed ectopic copy of the gene, indicating that this gene is essential for survival of T. cruzi epimastigotes. The pyrazole sulphonamide NMT inhibitor DDD85646 is 13–23-fold less potent against recombinant TcNMT than TbNMT (T. brucei NMT), with Ki values of 12.7 and 22.8 nM respectively, by scintillation proximity or coupled assay methods. DDD85646 also inhibits growth of T. cruzi epimastigotes (EC50=6.9 μM), but is ~1000-fold less potent than that reported for T. brucei. On-target activity is demonstrated by shifts in cell potency in lines that over- and under-express NMT and by inhibition of intracellular N-myristoylation of several proteins in a dose-dependent manner. Collectively, our findings suggest that N-myristoylation is an essential and druggable target in T. cruzi.
Primary structural features of SR-like protein acinusS govern the phosphorylation mechanism by SRPK2
Authors: Liang Ning , Zeng Chuyue , Tao Kin Pong , Sou Weng Hong , Hsia Ho Pan , Qu Dan , Lau Sze Nga , Ngo Jacky Chi Ki
Published: January 2014

SRPKs (serine/arginine protein kinases) are highly specific kinases that recognize and phosphorylate RS (Arg-Ser) dipeptide repeats. It has been shown previously that SRPK1 phosphorylates the RS domain of SRSF1 (serine/arginine splicing factor 1) at multiple sites using a directional and processive mechanism. Such ability to processively phosphorylate substrates is proposed to be an inherent characteristic of SRPKs. SRPK2 is highly related to SRPK1 in sequence and in vitro properties, yet it has been shown to have distinct substrate specificity and physiological function in vivo. To study the molecular basis for substrate specificity of SRPK2, we investigated the roles of the non-kinase regions and a conserved docking groove of SRPK2 in the recognition and phosphorylation of different substrates: SRSF1 and acinusS. Our results reveal that a conserved electronegative docking groove in SRPK2, but not its non-kinase regions, is responsible for substrate binding regardless of their identities. Although SRPK2 phosphorylates SRSF1 in a processive manner as predicted, an electronegative region on acinusS restricts SRPK2 phosphorylation to a single specific site despite the presence of multiple RS dipeptides. These results suggest that primary structural elements on the substrates serve as key regulatory roles in determining the phosphorylation mechanism of SRPK2.
Design and optimisation of compact RF energy harvesting device for smart applications
Authors: Ajmal T. , Dyo V. , Allen B. , Jazani D. , Ivanov I.
Published: January 2014

An optimised design of a radio frequency energy harvesting antenna is presented. The antenna is based on a compact ferrite rod which, together with the electronics, can directly replace batteries in suitable applications. The antenna is optimised such that the energy available for the applications is maximised, while considering constraints such as the device geometry and the Q‐factor. That the antenna can power a wireless sensor node is shown from the ambient medium wave transmissions.
Reduction of low‐frequency harmonics in modular multilevel converters (MMCs) by harmonic function analysis
Authors: Wang Can , Hao Quanrui , Ooi Boon‐Teck
Published: January 2014

Modular multilevel converter (MMC) is troubled by the inherent second harmonic of single‐phase ac power. By adding feedforward to the modulation signal, low‐frequency harmonic voltages are significantly reduced thus overcoming an important weakness of MMC. Capacitors of sub‐modules do not have to be over‐sized. If desired for protection, transformers can be wye‐connected with grounded neutral. The reduction method is based on harmonic function analysis. In addition to deriving algebraic formulae of harmonic voltage components of ‘open loop’ control, this study makes original contributions by deriving formulae which include feedforward control. Analytical insights from the formulae have shown the way to design feedforward methods to reduce low‐frequency harmonics. Validation is by simulations using SIMULINK/MATLAB.
Frequency selective surface for radio frequency energy harvesting applications
Authors: Keyrouz Shady , Perotto Gianluca , Visser Hubregt J.
Published: January 2014

A novel application for frequency selective surfaces (FSSs) is presented. The novel FSS design can harvest power from arbitrarily polarised incident waves. The design does not involve a matching network, which results in a simple, polarisation‐independent power harvester. An accurate analytical procedure, to calculate the impedance of the commercially available Schottky rectifiers, is presented. The results are validated by full‐wave simulations and by measurements. A simple equivalent circuit model to predict the transmission and reflection characteristics of the gridded‐square‐loop FSS is employed. The design method is validated for different polarisations and for different incident angles. The addition of lumped elements (R, L, C) in the metallic conductive grid of the FSS is investigated. The waveguide simulator method and full‐wave simulations are employed to validate the derived analytical equations. A 3 × 3 and a 5 × 5 RF harvesting FSS have been designed, simulated, fabricated and validated. A radio frequency (RF) to DC conversion efficiency of 25% for the 3 × 3 RF harvester and 15.9% for the 5 × 5 RF harvester is measured at an RF input power level of −6 dBm.
Voltage magnitude and frequency control of three‐phase voltage source inverter for seamless transfer
Authors: Guo Zhiqiang , Sha Deshang , Liao Xiaozhong
Published: January 2014

This study presents voltage magnitude and frequency control of a three‐phase voltage source inverter for distributed generations to achieve a seamless transfer between grid‐tied mode and intentional islanding mode. When the grid is normal, the inverter works in grid‐tied mode. On the contrary, when the grid fault occurs, the breaker connecting the inverter to the grid must be turned off and the inverter just supplies the power for local loads. By varying the frequency and the magnitude of the inverter output voltage, an output power control, with which the output active and reactive power can be precisely controlled, is presented. To improve the transient response, a virtual inductor with high‐pass filter in synchronous d–q frame is proposed. The effectiveness of the virtual inductor is explained by the frequency response of the inverter. Finally, experimental results are given to verify the effectiveness of the scheme.
Development of ultralow energy (1–10 eV) ion scattering spectrometry coupled with reflection absorption infrared spectroscopy and temperature programmed desorption for the investigation of molecular solids
Authors: Bag Soumabha , Bhuin Radha Gobinda , Methikkalam Rabin Rajan J. , Pradeep T. , Kephart Luke , Walker Jeff , Kuchta Kevin , Martin Dave , Wei Jian
Published: January 2014

Extremely surface specific information, limited to the first atomic layer of molecular surfaces, is essential to understand the chemistry and physics in upper atmospheric and interstellar environments. Ultra low energy ion scattering in the 1–10 eV window with mass selected ions can reveal extremely surface specific information which when coupled with reflection absorption infrared (RAIR) and temperature programmed desorption (TPD) spectroscopies, diverse chemical and physical properties of molecular species at surfaces could be derived. These experiments have to be performed at cryogenic temperatures and at ultra high vacuum conditions without the possibility of collisions of neutrals and background deposition in view of the poor ion intensities and consequent need for longer exposure times. Here we combine a highly optimized low energy ion optical system designed for such studies coupled with RAIR and TPD and its initial characterization. Despite the ultralow collision energies and long ion path lengths employed, the ion intensities at 1 eV have been significant to collect a scattered ion spectrum of 1000 counts/s for mass selected CH2+.
A hollow cathode ion source for production of primary ions for the BNL electron beam ion source
Authors: Alessi James , Beebe Edward , Carlson Charles , McCafferty Daniel , Pikin Alexander , Ritter John
Published: January 2014

A hollow cathode ion source, based on one developed at Saclay, has been modified significantly and used for several years to produce all primary 1+ ions injected into the Relativistic Heavy Ion Collider Electron Beam Ion Source (EBIS) at Brookhaven. Currents of tens to hundreds of microamperes have been produced for 1+ ions of He, C, O, Ne, Si, Ar, Ti, Fe, Cu, Kr, Xe, Ta, Au, and U. The source is very simple, relying on a glow discharge using a noble gas, between anode and a solid cathode containing the desired species. Ions of both the working gas and ionized sputtered cathode material are extracted, and then the desired species is selected using an ExB filter before being transported into the EBIS trap for charge breeding. The source operates pulsed with long life and excellent stability for most species. Reliable ignition of the discharge at low gas pressure is facilitated by the use of capacitive coupling from a simple toy plasma globe. The source design, and operating experience for the various species, is presented.
Dependence of beam emittance on plasma electrode temperature and rf-power, and filter-field tuning with center-gapped rod-filter magnets in J-PARC rf-driven H− ion source
Authors: Ueno A. , Koizumi I. , Ohkoshi K. , Ikegami K. , Takagi A. , Yamazaki S. , Oguri H.
Published: January 2014

The prototype rf-driven H− ion-source with a nickel plated oxygen-free-copper (OFC) plasma chamber, which satisfies the Japan Proton Accelerator Research Complex (J-PARC) 2nd stage requirements of a H− ion beam current of 60 mA within normalized emittances of 1.5 π mm mrad both horizontally and vertically, a flat top beam duty factor of 1.25% (500 μs × 25 Hz) and a life-time of more than 50 days, was reported at the 3rd international symposium on negative ions, beams, and sources (NIBS2012). The experimental results of the J-PARC ion source with a plasma chamber made of stainless-steel, instead of nickel plated OFC used in the prototype source, are presented in this paper. By comparing these two sources, the following two important results were acquired. One was that the about 20% lower emittance was produced by the rather low plasma electrode (PE) temperature (TPE) of about 120 °C compared with the typically used TPE of about 200 °C to maximize the beam current for the plasma with the abundant cesium (Cs). The other was that by using the rod-filter magnets with a gap at each center and tuning the gap-lengths, the filter-field was optimized and the rf-power necessary to produce the J-PARC required H− ion beam current was reduced typically 18%. The lower rf-power also decreases the emittances.
Space-charge compensation measurements in electron cyclotron resonance ion source low energy beam transport lines with a retarding field analyzer
Authors: Winklehner D. , Leitner D. , Cole D. , Machicoane G. , Tobos L.
Published: January 2014

In this paper we describe the first systematic measurement of beam neutralization (space charge compensation) in the ECR low energy transport line with a retarding field analyzer, which can be used to measure the potential of the beam. Expected trends for the space charge compensation levels such as increase with residual gas pressure, beam current, and beam density could be observed. However, the overall levels of neutralization are consistently low (<60%). The results and the processes involved for neutralizing ion beams are discussed for conditions typical for ECR injector beam lines. The results are compared to a simple theoretical beam plasma model as well as simulations.
Nonadiabatic dynamics of electron transfer in solution: Explicit and implicit solvent treatments that include multiple relaxation time scales
Authors: Schwerdtfeger Christine A. , Soudackov Alexander V. , Hammes-Schiffer Sharon
Published: January 2014

The development of efficient theoretical methods for describing electron transfer (ET) reactions in condensed phases is important for a variety of chemical and biological applications. Previously, dynamical dielectric continuum theory was used to derive Langevin equations for a single collective solvent coordinate describing ET in a polar solvent. In this theory, the parameters are directly related to the physical properties of the system and can be determined from experimental data or explicit molecular dynamics simulations. Herein, we combine these Langevin equations with surface hopping nonadiabatic dynamics methods to calculate the rate constants for thermal ET reactions in polar solvents for a wide range of electronic couplings and reaction free energies. Comparison of explicit and implicit solvent calculations illustrates that the mapping from explicit to implicit solvent models is valid even for solvents exhibiting complex relaxation behavior with multiple relaxation time scales and a short-time inertial response. The rate constants calculated for implicit solvent models with a single solvent relaxation time scale corresponding to water, acetonitrile, and methanol agree well with analytical theories in the Golden rule and solvent-controlled regimes, as well as in the intermediate regime. The implicit solvent models with two relaxation time scales are in qualitative agreement with the analytical theories but quantitatively overestimate the rate constants compared to these theories. Analysis of these simulations elucidates the importance of multiple relaxation time scales and the inertial component of the solvent response, as well as potential shortcomings of the analytical theories based on single time scale solvent relaxation models. This implicit solvent approach will enable the simulation of a wide range of ET reactions via the stochastic dynamics of a single collective solvent coordinate with parameters that are relevant to experimentally accessible systems.
Fluorescence modulation in single CdSe quantum dots by moderate applied electric fields
Authors: LeBlanc Sharonda J. , McClanahan Mason R. , Moyer Tully , Jones Marcus , Moyer Patrick J.
Published: January 2014

Single molecule time-resolved fluorescence spectroscopy of CdSe/ZnS core-shell quantum dots (QDs) under the influence of moderate applied electric fields reveals distributed emission from states which are neither fully on nor off and pronounced changes in the excited state decay. The data suggest that a 54 kV/cm applied electric field causes small perturbations to the QD surface charge distribution, effectively increasing the surface trapping probability and resulting in the appearance of gray states. We present simultaneous blinking and fluorescence decay results for two sets of QDs, with and without an applied electric field. Further kinetic modeling analysis suggests that a single trapped charged cannot be responsible for a blinking off event.
Evaluation of magnetic flux distribution from magnetic domains in [Co/Pd] nanowires by magnetic domain scope method using contact-scanning of tunneling magnetoresistive sensor
Authors: Okuda Mitsunobu , Miyamoto Yasuyoshi , Miyashita Eiichi , Hayashi Naoto
Published: January 2014

Current-driven magnetic domain wall motions in magnetic nanowires have attracted great interests for physical studies and engineering applications. The magnetic force microscope (MFM) is widely used for indirect verification of domain locations in nanowires, where relative magnetic force between the local domains and the MFM probe is used for detection. However, there is an occasional problem that the magnetic moments of MFM probe influenced and/or rotated the magnetic states in the low-moment nanowires. To solve this issue, the “magnetic domain scope for wide area with nano-order resolution (nano-MDS)” method has been proposed recently that could detect the magnetic flux distribution from the specimen directly by scanning of tunneling magnetoresistive field sensor. In this study, magnetic domain structure in nanowires was investigated by both MFM and nano-MDS, and the leakage magnetic flux density from the nanowires was measured quantitatively by nano-MDS. Specimen nanowires consisted from [Co (0.3)/Pd (1.2)]21/Ru(3) films (units in nm) with perpendicular magnetic anisotropy were fabricated onto Si substrates by dual ion beam sputtering and e-beam lithography. The length and the width of the fabricated nanowires are 20 μm and 150 nm. We have succeeded to obtain not only the remanent domain images with the detection of up and down magnetizations as similar as those by MFM but also magnetic flux density distribution from nanowires directly by nano-MDS. The obtained value of maximum leakage magnetic flux by nano-MDS is in good agreement with that of coercivity by magneto-optical Kerr effect microscopy. By changing the protective diamond-like-carbon film thickness on tunneling magnetoresistive sensor, the three-dimensional spatial distribution of leakage magnetic flux could be evaluated.
Current induced domain wall dynamics in the presence of spin orbit torques
Authors: Boulle O. , Buda-Prejbeanu L. D. , Jué E. , Miron I. M. , Gaudin G.
Published: January 2014

Current induced domain wall (DW) motion in perpendicularly magnetized nanostripes in the presence of spin orbit torques is studied. We show using micromagnetic simulations that the direction of the current induced DW motion and the associated DW velocity depend on the relative values of the field like torque (FLT) and the Slonczewski like torques (SLT). The results are well explained by a collective coordinate model which is used to draw a phase diagram of the DW dynamics as a function of the FLT and the SLT. We show that a large increase in the DW velocity can be reached by a proper tuning of both torques.
Tunable gaps and enhanced mobilities in strain-engineered silicane
Authors: Restrepo Oscar D. , Mishra Rohan , Goldberger Joshua E. , Windl Wolfgang
Published: January 2014

The recent demonstration of single-atom thick, sp3-hybridized group 14 analogues of graphene enables the creation of materials with electronic structures that are manipulated by the nature of the covalently bound substituents above and below the sheet. These analogues can be electronically derived from isolated (111) layers of the bulk diamond lattice. Here, we perform systematic Density Functional Theory calculations to understand how the band dispersions, effective masses, and band gaps change as the bulk silicon (111) layers are continuously separated from each other until they are electronically isolated, and then passivated with hydrogen. High-level calculations based on HSE06 hybrid functionals were performed on each endpoint to compare directly with experimental values. We find that the change in the electronic structure due to variations in the Si-H bond length, Si-Si-Si bond angle, and most significantly the Si-Si bond length can tune the nature of the band gap from indirect to direct with dramatic effects on the transport properties. First-principles calculations of the phonon-limited electron mobility predict a value of 464 cm2/Vs for relaxed indirect band gap Si-H monolayers at room temperature. However, for 1.6% tensile strain, the band gap becomes direct, which increases the mobility significantly (8 551 cm2/Vs at 4% tensile strain). In total, this analysis of Si-based monolayers suggests that strain can change the nature of the band gap from indirect to direct and increase the electron mobility more than 18-fold.
Probing the metal-insulator transition in nickelates using soft x-ray absorption spectroscopy
Authors: Bruno F. Y. , Valencia S. , Abrudan R. , Dumont Y. , Carrétéro C. , Bibes M. , Barthélémy A.
Published: January 2014

We have investigated the spectral changes occurring at the Ni-L3,2 edge X-ray absorption spectrum of SmNiO3 epitaxial thin films as the temperature is varied across the metal-insulator transition. We show that in the low temperature insulating state, a clear multiplet structure gives rise to two peaks at the L3 edge. As the temperature is increased the energy splitting between these peaks remains constant, being reduced only upon crossing the metal-insulator transition. We analyze films with varying strain-engineered metal-insulator transition temperatures and elucidate the separate effects of strain and temperature in the absorption spectra.
Nonlinear luminescence response of CaF2:Eu and YAlO3:Ce to single-ion excitation
Authors: Liu Peng , Zhang Yanwen , Xiao Haiyan , Xiang Xia , Wang Xuelin , Weber William J.
Published: January 2014

Understanding scintillation physics and nonproportionality is essential to accelerate materials discovery that has been restricted due to the difficulties inherent to large crystal growth and complex nature of gamma-solid interaction. Taking advantage of less restrictive growth and deposition techniques for smaller crystal sizes or thin films and better fundamental understanding of ion-solid interactions, a unique ion approach is demonstrated to effectively screen candidate scintillators with relatively small size and evaluate their nonlinear scintillation response. Response of CaF2:Eu and YAlO3:Ce scintillators to single ions of H+, He+, and O3+ are measured by the corresponding pulse height over a continuous energy range using a time-of-flight–scintillator–photoelectric multiplier tube apparatus. Nonlinear response of the scintillators under ionizing ion irradiation is quantitatively evaluated by considering the energy partitioning process. In a differential energy deposition region with negligible displacement damage, the low, medium and high excitation energy deposition density (Dexci) can be produced by energetic H+, He+ and O3+ ions, respectively, and significantly different impacts on the response characteristics of these two benchmark scintillators are observed. For CaF2:Eu, the scintillation efficiency under ion irradiation monotonically decreases with increasing excitation-energy density. In contrast, the response efficiency of YAlO3:Ce scintillation initially increases with excitation-energy density at low excitation-energy densities, goes through a maximum, and then decreases with further increasing excitation-energy density. The fundamental mechanism causing these different response behaviours in the scintillators is based on the competition between the scintillation response and the nonradiative quenching process under different excitation densities, which is also the main origin of the nonlinear response of the scintillators to irradiation.
Spatial coherence measurements of non-resonant and resonant high harmonics generated in laser ablation plumes
Authors: Ganeev R. A. , Abdelrahman Z. , Frank F. , Witting T. , Okell W. A. , Fabris D. , Hutchison C. , Marangos J. P. , Tisch J. W. G.
Published: January 2014

We present measurements of the spatial coherence of the high-order harmonics generated in laser-produced ablation plumes. Harmonics were generated using 4 fs, 775 nm pulses with peak intensity 3 × 1014 W cm−2. Double-slit fringe visibilities in the range of ≈0.6–0.75 were measured for non-resonant harmonics in carbon and resonantly enhanced harmonics in zinc and indium. These are somewhat higher than the visibility obtained for harmonics generated in argon gas under similar conditions. This is attributed to lower time-dependent ionization of the plasma ablation targets compared to argon during the high harmonics generation process.