bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a two-wheel mobile manipulator: balancing and interaction control
Authors: Ahn Jae Kook , Jung Seul
Published: January 2014

This paper focuses on practical application of a mobile manipulator by presenting the development and control of a two-wheel mobile robot with two arms called a balancing service robot (BSR) designated for indoor services. The mobile manipulator requires not only robust balancing position control but also force control to interact with objects. Movements with two wheels are controlled to satisfy stable balancing control for navigation and manipulation with two arms to perform given tasks. The robot is required to deal with external forces to maintain balance. The position-based impedance force control method (the admittance control) is utilized by filtering the force with the impedance function to react to the applied force from the operator. Experimental studies of navigation control under balancing condition and interacting control with a human operator are demonstrated. Experimental results confirm that the robot has smooth reaction against the disturbance induced by the applied external force.
Mumps virus infection in vaccinated patients can be detected by an increase in specific IgG antibodies to high titres: a retrospective study
Authors: BORGMANN S. , SCHWAB F. , SANTIBANEZ S. , MANKERTZ A.
Published: January 2014

Mumps outbreaks in highly vaccinated populations with genotype G have been reported repeatedly. Detection of these outbreaks can be difficult in a setting with relatively high vaccination coverage when acute cases of mumps are routinely diagnosed by IgM serology since this marker is not reliable for diagnosis of mumps re-infection. To learn whether diagnostic tests performed in a large private laboratory may be useful to detect mumps outbreaks retrospectively, we reviewed the results of almost 7000 mumps tests. Two groups were compared: group 1 comprised of 3438samples from patients submitted by physicians and clinicians (it was assumed that these patients visited their doctor due to acute disease). Group 2 comprised of 3398 samples submitted from company medical officers and occupational physicians. Since these patients usually attend for routine check-ups and certification of immunity to vaccine-preventable diseases, these samples comprised a control group. From July 2010 to May 2011, a mumps virus outbreak with more than 300 cases occurred in Bavaria, Southeast Germany. Our study includes samples received for serological mumps tests from January 2009 until December 2011 (36 months). The two groups were analysed with regard to the number of IgM-positive cases per month and the level of IgG titre. We found a marked increase for both parameters in group 1 during the time of the outbreak, while the samples submitted by the occupational medical physicians did not display significant alterations. These parameters reflect the outbreak with high accuracy, indicating that a retrospective analysis of IgG titres may be a useful tool for detection of mumps outbreaks when, as was the case in Germany, (i) a nationwide notification system has not been implemented and (ii) a highly vaccinated population is affected.
Use of the pressure wire method for measuring pulmonary arterial pressures in patients with pulmonary atresia
Authors: Haddad Jorge L. , Novaes Gustavo C. , Figueiredo Geraldo L. , Lemos Daniel C. , Macedo Leon G. R. , Lago Igor M. , Pavão Rafael B. , Badran André V. , Lima-Filho Moysés O. , Manso Paulo H. , Marin-Neto José A.
Published: January 2014

Objective:The objective of the study was to analyse the use of the pressure wire for the acquisition of intravascular pulmonary pressures in the presence of pulmonary atresia and systemic-dependent pulmonary blood flow.Methods:In this study, we included patients with pulmonary atresia and systemic-dependent pulmonary circulation referred for diagnostic catheterisation for evaluation of pulmonary pressures during the period from April, 2012 to April, 2013. The systemic-pulmonary collateral arteries were selectively catheterised, and in the absence of a critical stenosis angiographically determined; the pressure wire was introduced in these arteries to reach the main pulmonary artery, and/or lobar, and segmental branches. Aortic and pulmonary pressures were simultaneously obtained. We evaluated the feasibility and safety of the method.Results:We studied 10 patients (age 21 days to 11 years). In all of them, the pressures of pulmonary circulation – main artery, and/or lobar, and segmental branches – were successfully measured with the pressure wire. Of eight patients with indication for Rastelli surgery, the pulmonary pressures were considered normal in five, and slightly increased in three. In two patients requiring univentricular correction – total cavopulmonary anastomosis – the diastolic pressure was increased (20 mmHg). All procedures were performed without haemodynamic instability, cardiac arrhythmia, systemic saturation reduction, death, or any other complication.Conclusion:Measurement of pulmonary vascular pressures using the pressure wire in small patients with pulmonary atresia is safe and effective. It allows the acquisition of reliable pressure curves, even in the presence of small vessels, bending and tortuosity, without the risk usually associated with the use of conventional diagnostic catheters.
Development of an Evaluation Framework Suitable for Assessing Humanitarian Workforce Competencies During Crisis Simulation Exercises
Authors: Cranmer Hilarie , Chan Jennifer L. , Kayden Stephanie , Musani Altaf , Gasquet Philippe E. , Walker Peter , Burkle Frederick M. , Johnson Kirsten
Published: January 2014

The need to provide a professionalization process for the humanitarian workforce is well established. Current competency-based curricula provided by existing academically affiliated training centers in North America, the United Kingdom, and the European Union provide a route toward certification. Simulation exercises followed by timely evaluation is one way to mimic the field deployment process, test knowledge of core competences, and ensure that a competent workforce can manage the inevitable emergencies and crises they will face. Through a 2011 field-based exercise that simulated a humanitarian crisis, delivered under the auspices of the World Health Organization (WHO), a competency-based framework and evaluation tool is demonstrated as a model for future training and evaluation of humanitarian providers.

CranmerH, ChanJ, KaydenS, MusaniA, GasquetP, WalkerP, BurkleF, JohnsonK. Development of an evaluation framework suitable for assessing humanitarian workforce competencies during crisis simulation exercises. Prehosp Disaster Med. 2014;29(1):1-6.
Dietary patterns and breakfast consumption in relation to insulin resistance in children. The Healthy Growth Study
Authors: Karatzi Kalliopi , Moschonis George , Barouti Afroditi-Alexandra , Lionis Christos , Chrousos George P , Manios Yannis
Published: January 2014

Objective

Insulin resistance is a significant cross-point for the manifestation of several chronic diseases in children and adults. The aim of the present study was to investigate the possible relationship of certain dietary patterns and breakfast consumption habits with insulin resistance in children.

Subjects

A representative sample of 1912 schoolchildren (aged 9–13 years) participated in a cross-sectional epidemiological study, the Healthy Growth Study, which was initiated in May 2007 and completed in June 2009.

Setting

It was conducted in seventy-seven primary schools in four large regions in Greece.

Design

Dietary intake, breakfast consumption, anthropometric and physical examination data, biochemical indices and socio-economic information collected from parents were assessed in all children. Principal components analysis was used to identify dietary patterns.

Results

A dietary pattern of increased consumption of margarine, sweets (candies, lollipops, jellies, traditional fruit in heavy syrup) and savoury snacks (chips, cheese puffs and not home-made popcorn) was associated with homeostasis model assessment of insulin resistance index (HOMA-IR;β= 0·08,P< 0·001) in multivariate models. Children in the third tertile of this dietary pattern had a 2·51 (95 % CI 1·30, 4·90) times higher risk of insulin resistance (HOMA-IR > 3·16) than those in the first tertile. Breakfast consumption had an inverse correlation with insulin resistance, but the correlation lost its significance after adjustments for waist circumference, birth weight, parental BMI and socio-economic status.

Conclusions

Increased consumption of margarine, sweets and savoury snacks, which is a common dietary pattern in childhood, was positively associated with insulin resistance, while breakfast consumption had an inverse association with HOMA-IR, in schoolchildren (aged 9–13 years). Identification of dietary behaviours that might affect insulin resistance in children offers valuable advice in cardiometabolic risk prevention strategies.
Research on subsoil biopores and their functions in organically managed soils: A review
Authors: Kautz Timo
Published: January 2014

The living soil is the basis for crop production in organic agriculture. Biopores are voids in the soil which were formed by the activity of soil life. The first scientific studies on biopores were published in the 1870s–90s by Victor Hensen who stated that earthworms were opening channels to the subsoil and coating them with humus, thus creating a beneficial environment for root growth. His work was originally widely recognized, but then research on biopores was neglected for many decades and was only revitalized with the rise of ecological concerns in the 1960s. In recent times, biopores have attracted the attention of agronomists with a focus on organic agriculture. New visualization techniques, such as X-ray micro computed tomography,in-situendoscopy and nuclear magnetic resonance imaging have been applied. Biopores contribute to air transport through the soil, increase water infiltration, reduce water runoff and soil erosion, serve as preferential pathways for root elongation and can facilitate the acquisition of water and nutrients from the subsoil. The relevance of biopores for nutrient acquisition can be pronounced particularly in organic production systems, where crops are more dependent on nutrient acquisition from the solid soil phase than under conditions of conventional agriculture. Organic land-use strategies should aim to increase number, stability and quality of biopores. The biopore density can be increased by the share of dicotyledons in the crop rotation and by cultivating perennial crops with taproot systems. Moreover, density and—in particular—the quality of biopores, e.g., the nutrient contents of pore walls, can be influenced by anecic earthworms which can be promoted by adapted tillage practices.
A qualitative study of clinicians’ experiences and attitudes towards telephone triage mental health assessments
Authors: Jones Elizabeth A. , Bale Hazell L. , Morera Tirma
Published: January 2014

This qualitative study investigated clinicians’ experiences and attitudes towards conducting mental health assessments over the telephone in an IAPT service. Nine participants completed a semi-structured questionnaire and data were evaluated using a Thematic Analysis model. Participants were largely apprehensive about telephone working, but many reported positive experiences. Telephone assessments were felt to be structured, focused and comprehensive, and therapeutic rapport was able to be established. However, concerns persisted around whether risk assessments could be adequately conducted over the telephone. Reports of spontaneous feedback from patients during telephone triage suggested that there was appreciation for this method of assessment and that it increased access to the service. Further research is needed to better understand what, for clinicians, contributes to acceptable assessment of complex and subjective situations, such as risk and feeling states, over the telephone.
Duffy antigen / receptor for chemokines correlates with inflammatory reaction in rats with venous hypertension: implication for the pathogenesis of primary chronic venous disease
Authors: Huang Weibin , Qin Weiwei , Lv Lei , Deng Haoyv , Zhang Hao , Zhang Jiwei , Zhang Lan
Published: January 2014

Background: Duffy antigen / receptor for chemokines (DARC) possesses high affinity for several chemokine subgroups of CC and CXC. Although DARC has been shown to play a role in many inflammatory diseases, its effect on chronic venous disease (CVD) remains unidentified. We explored whether the expression of DARC in skin tissue was activated under venous hypertension as well as the relationships between DARC and inflammation. Materials and methods: The inflammation in a rat model of venous hypertension caused by a femoral arterial-venous fistula (AVF) was studied. At specified intervals the pressure in the femoral veins was recorded within 42 days. Hindlimb skin specimens were harvested at different time points. The expressions of DARC, interleukin-8 (IL-8), and monocyte chemotactic protein-1 (MCP-1) in skin tissue were examined. Mononuclear cells infiltrated in skin tissue were detected. Results: Femoral venous pressures in AVF groups increased significantly at different time points (P < 0.01). DARC was expressed in skin tissue and its expression level increased significantly in AVF groups from the 7nd day on and was enhanced in a time-dependent manner within 42 days (P < 0.05). Meanwhile, both MCP-1 and IL-8 had higher levels, accompanied by increased mononuclear cells infiltrating into skin tissue (P < 0.05). Conclusions: A rat AVF model which can maintain venous hypertension for at least 42 days is competent for researching the pathogenesis of CVD. DARC, which plays a role in the inflammation of skin tissue under venous hypertension, may become a new molecular target for diagnosis and treatment of CVD at a very early stage.
Haemostasis for 568 large femoral artery access sites - outcomes and predictors of success
Authors: Kuhelj Dimitrij , Salapura Vladka , Boc Nina
Published: January 2014

Background: The introduction of stent grafts for thoracic and abdominal aorta (T / EVAR) has raised the demand for percutaneous closure devices for larger femoral arterial access sites. The aim of our study was to evaluate the success and complication rate of completely percutaneous T / EVAR with Prostar XL® and surgical haemostasis over a 50- month period. Patients and methods: Between December 16th 2005 and February 17th 2010 T / EVAR was performed in 306 patients with 568 arterial access sites with diameters of 12 to 24 Fr. The exclusion criteria for percutaneous haemostasis were a calcified anterior wall at the puncture site and / or a stenotic common femoral artery, seen on computed tomographic angiography. Results: Surgical haemostasis was performed in 184 (32.4 %, o-T / EVAR group) while percutaneous haemostasis was attempted at 384 sites (67.6 %, p-T / / EVAR group). Most of the procedures were elective; five of twelve emergency patients had percutaneous haemostasis that was successful in all. Percutaneous haemostasis failed at 23 sites. No data about follow-up was recorded for 54 sites (9,5 %). The technical success rate of percutaneous haemostasis was 93.6 % (338 / 361 sites). A larger size of the access site resulted in significantly more complications of haemostasis in both groups (p-T / EVAR group p = 0.019; o-T / EVAR group p = 0.003). p-T / EVAR caused more mild complications compared to o-T / EVAR (p = 0.03). No deaths as consequence of failed haemostasis were recorded. Conclusions: Complete percutaneous T / EVAR is technically feasible and safe in a majority of patients. Good patient selection based on adequate pre-procedural imaging and technical expertise of the operators are key to success. Surgical back-up is strongly recommended to assist in those patients in whom p-T / EVAR fails.
Maßgeschneiderte Frühförderung?
Authors: Stamm Margrit
Published: January 2014

Allgemein ist bekannt, dass die soziale Herkunft die Entwicklung von Kindern langfristig beeinflusst und dabei das elterliche Engagement eine Rolle spielt. Da bisher fast ausschließlich Erkenntnisse zu benachteiligten, kaum jedoch zu bildungsnahen Familien vorliegen, stehen diese im Mittelpunkt des vorliegenden Beitrages. Anhand der Daten einer Längsschnittstudie wird untersucht, wie ausgeprägt Mittelschichteltern ihre Kinder fördern und welche Faktoren dieses Ausmaß erklären können. Im Ergebnis zeigt sich erstens, dass private Fördermaßnahmen sehr verbreitet sind und auch beträchtliche Finanzen dafür aufwendet werden. Zweitens besitzen die elterlichen Erwartungshaltungen und die primäre Betreuungszeit die stärkste Erklärungskraft für das Ausmaß der privaten Fördermaßnahmen, wobei jedoch ein Hochschulabschluss seinen eigenständigen Einfluss behält. Auf dieser Basis werden ein paar pädagogische und bildungspolitische Konsequenzen formuliert, welche für den Vorschulbereich wichtig sind.
Correlation of X-Ray Vector Radiography to Bone Micro-Architecture
Authors: Schaff Florian , Malecki Andreas , Potdevin Guillaume , Eggl Elena , Noël Peter B. , Baum Thomas , Garcia Eduardo Grande , Bauer Jan S. , Pfeiffer Franz
Published: January 2014

Besides the overall mass density, strength of trabecular bone depends significantly on its microstructure. However, due to dose constraints in medical CT imaging, it is impossible to gain sufficient information about very fine bone structures in vivo on the micrometer scale. Here we show that a recently developed method of X-ray vector radiography (XVR), an imaging method which uses X-ray scattering information to form an image, allows predictions on the bone microstructure without the explicit need to spatially resolve even individual trabeculae in the bone. We investigated thick human femoral bone samples and compared state-of-the-art μCT data with XVR imaging. A model is presented which proves that XVR imaging yields information directly correlated with the trabecular microstructure. This opens up possibilities of using XVR as a tool to help early diagnosis of bone diseases, such as osteoporosis.
Orbital-specific Tunability of Many-Body Effects in Bilayer Graphene by Gate Bias and Metal Contact
Authors: Fukidome Hirokazu , Kotsugi Masato , Nagashio Kosuke , Sato Ryo , Ohkochi Takuo , Itoh Takashi , Toriumi Akira , Suemitsu Maki , Kinoshita Toyohiko
Published: January 2014

Graphene, a 2D crystal bonded by π and σ orbitals, possesses excellent electronic properties that are promising for next-generation optoelectronic device applications. For these a precise understanding of quasiparticle behaviour near the Dirac point (DP) is indispensable because the vanishing density of states (DOS) near the DP enhances many-body effects, such as excitonic effects and the Anderson orthogonality catastrophe (AOC) which occur through the interactions of many conduction electrons with holes. These effects renormalize band dispersion and DOS and therefore affect device performance. For this reason, we have studied the impact of the excitonic effects and the AOC on graphene device performance by using X-ray absorption spectromicroscopy on an actual graphene transistor in operation. Our work shows that the excitonic effect and the AOC are tunable by gate bias or metal contacts, both of which alter the Fermi energy and are orbital-specific.
Negative Interactions and Feedback Regulations Are Required for Transient Cellular Response
Authors: Mobashir Mohammad , Madhusudhan Thati , Isermann Berend , Beyer Tilo , Schraven Burkhart
Published: January 2014

Signal transduction is a process required to conduct information from a receptor to the nucleus. This process is vital for the control of cellular function and fate. The dynamics of signaling activation and inhibition determine processes such as apoptosis, proliferation and differentiation. Thus, it is important to understand the factors modulating transient and sustained response. To address this question, by applying mathematical approach we have studied the factors which can alter the activation nature of downstream signaling molecules. The factors which we have investigated are loops (feed forward and feedback loops), cross-talk of signal transduction pathways and the change in the concentration of the signaling molecules. Based on our results we conclude that among these factors feedback loop and the cross-talks which directly inhibit the target protein dominantly controls the transient cellular response.
Disturbances in the murine hepatic circadian clock in alcohol-induced hepatic steatosis
Authors: Zhou Peng , Ross Ruth A. , Pywell Cameron M. , Liangpunsakul Suthat , Duffield Giles E.
Published: January 2014

To investigate the role of the circadian clock in the development of alcohol-induced fatty liver disease we examined livers of mice chronically alcohol-fed over 4-weeks that resulted in steatosis. Here we show time-of-day specific changes in expression of clock genes and clock-controlled genes, including those associated with lipid and bile acid regulation. Such changes were not observed following a 1-week alcohol treatment with no hepatic lipid accumulation. Real-time bioluminescence reporting of PERIOD2 protein expression suggests that these changes occur independently of the suprachiasmatic nucleus pacemaker. Further, we find profound time-of-day specific changes to the rhythmic synthesis/accumulation of triglycerides, cholesterol and bile acid and the NAD/NADH ratio, processes that are under clock control. These results highlight not only that the circadian timekeeping system is disturbed in the alcohol-induced hepatic steatosis state, but also that the effects of alcohol upon the clock itself may actually contribute to the development of hepatic steatosis.
HPLC/ICPMS with effluent diversion for robust and time-efficient determination of selenium metabolites in human urine
Authors: Kokarnig Sabine , Kroepfl Nina , Kuehnelt Doris , Francesconi Kevin A.
Published: January 2014

An HPLC/ICPMS method incorporates a methanol gradient and robust instrumental set-up to preclude high amounts of methanol entering the plasma.
The supramolecular design of low-dimensional carbon nano-hybrids encoding a polyoxometalate-bis-pyrene tweezer
Authors: Modugno Gloria , Syrgiannis Zois , Bonasera Aurelio , Carraro Mauro , Giancane Gabriele , Valli Ludovico , Bonchio Marcella , Prato Maurizio
Published: January 2014

The host–guest chemistry of the POM-tweezer drives self-assembly with carbon nanostructures in the nano- to micro-scale yielding 0-, 1-, and 2-D nano-hybrids.
Interweaving spins with their environment: novel inorganic nanohybrids with controllable magnetic properties
Authors: Cervetti Christian , Heintze Eric , Bogani Lapo
Published: January 2014

We discuss the developments in the synthesis and characterization of magnetic nanohybrids made of molecular magnets and nanostructured materials.
A novel manganese-doped large polyoxotitanate nanocluster
Authors: Chen Yang , Trzop Elzbieta , Makal Anna , Chen Yu-Sheng , Coppens Philip
Published: January 2014

The largest manganese-doped polyoxotitanate nanocluster so far, Ti28MnO36(OH)2(OEt)40, is reported. The coordination of the manganese dopant in polyoxotitanate nanoclusters and the impact of manganese doping on the band gap of the clusters are discussed.
Catalytic activity of MnOx/WO3 nanoparticles: synthesis, structure characterization and oxidative degradation of methylene blue
Authors: Amini Mojtaba , Pourbadiei Behzad , Ruberu T. Purnima A. , Woo L. Keith
Published: January 2014

MnOx/WO3 nanoparticles were found to be an effective catalyst for the degradation of methylene blue, an important industrial dye and a problematic pollutant.
Insulating to metallic transition of an oxidized boron nitride nanosheet coating by tuning surface oxygen adsorption
Authors: Guo Yufeng , Guo Wanlin
Published: January 2014

Insulating to metallic transition of oxidized h-BN nanosheets supported by substrates is induced by charge injection mediated O adsorption.
Polyaniline nanotubes with rectangular-hollow-core and its self-assembled surface decoration: high conductivity and dielectric properties
Authors: Paik Pradip , Manda Ramesh , Amgoth Chander , Santhosh Kumar K.
Published: January 2014

Self-assembled and surface decorated PANI nanotubes with rectangular hallow core with high electrical and dielectric properties.
Imaging lipid order changes in endosome membranes of live cells by using a Nile Red-based membrane probe
Authors: Darwich Zeinab , Klymchenko Andrey S. , Dujardin Denis , Mély Yves
Published: January 2014

Changes in the composition of endosome membranes during endocytosis can be imaged in live cells with the NR12S membrane probe.
A novel MOF/graphene oxide composite GrO@MIL-101 with high adsorption capacity for acetone
Authors: Zhou Xin , Huang Wenyu , Shi Jiao , Zhao Zhenxia , Xia Qibin , Li Yingwei , Wang Haihui , Li Zhong
Published: January 2014

The composite of MIL-101 and graphene oxide with remarkably improved acetone adsorption capacity was prepared. This composite exhibited enhanced porous structure and stronger adsorption interaction towards adsorbate. The mechanism of such improvement was discussed. Acetone adsorption on this composite was highly reversible.
Rubicene: a molecular fragment of C70 for use in organic field-effect transistors
Authors: Lee Hyunbok , Zhang Yue , Zhang Lei , Mirabito Timothy , Burnett Edmund K. , Trahan Stefan , Mohebbi Ali Reza , Mannsfeld Stefan C. B. , Wudl Fred , Briseno Alejandro L.
Published: January 2014

The field-effect hole mobility of rubicene having high ionization energy (∼5.5 eV) is 0.20 cm2 V−1 s−1 and is improved to 0.32 cm2 V−1 s−1 with PFBT SAM treatment which reduces the hole injection barrier and induces an edge-on configuration.
Characterization of bimetallic core–shell nanorings synthesized via ascorbic acid-controlled galvanic displacement followed by epitaxial growth
Authors: Ghosh Tanmay , Satpati Biswarup , Senapati Dulal
Published: January 2014

We demonstrate the role of ascorbic acid in synthesizing bimetallic core–shell nanorings at room temperature using the galvanic replacement reaction followed by epitaxial growth. The undefined gold triangular structures formed in the absence of ascorbic acid, whereas continuous gold rings formed using ascorbic acid.
Strain driven structural phase transformations in dysprosium doped BiFeO3 ceramics
Authors: Lennox Robert C. , Price Mark C. , Jamieson William , Jura Marek , Daoud-Aladine Aziz , Murray Claire A. , Tang Chiu , Arnold Donna C.
Published: January 2014

Chemical strain effects arising from the large size mismatch between the two A-site cations results in a lowering of the symmetry from polar R3c to a polar Cc in Bi0.95Dy0.05FeO3.
Insight into the mechanism of nanodiamond catalysed decomposition of methane molecules
Authors: Zhong Bingwei , Zhang Jian , Li Bo , Zhang Bingsen , Dai Chunli , Sun Xiaoyan , Wang Rui , Su Dang Sheng
Published: January 2014

Nanodiamond can catalyze the decomposition of methane, and its initial rate is linearly dependent on the number of –CHCH– defective sites.
NHC-coordinated silagermenylidene functionalized in allylic position and its behaviour as a ligand
Authors: Jana Anukul , Majumdar Moumita , Huch Volker , Zimmer Michael , Scheschkewitz David
Published: January 2014

Through coordination by an N-heterocyclic carbene (NHC) silagermenylidene (Tip2Cl)Si-(Tip)SiGe·NHCiPr2Me2 (4-E/Z; Tip = 2,4,6-iPr3C6H2; NHCiPr2Me2 = 1,3-iPr2-4,5-Me2imidazol-2-ylidene) is available as an E/Z-equilibrium mixture from Tip2SiSi(Tip)Li and NHCiPr2Me2·GeCl2.
Substrate interaction dynamics and oxygen control in the active site of thymidylate synthase ThyX
Authors: Becker Hubert F. , Djaout Kamel , Lamarre Isabelle , Ulmer Jonathan E. , Schaming Delphine , Balland Véronique , Liebl Ursula , Myllykallio Hannu , Vos Marten H.
Published: January 2014

Thymidylate synthase ThyX, required for DNA synthesis in many pathogenic bacteria, is considered a promising antimicrobial target. It binds FAD and three substrates, producing dTMP (2′-deoxythymidine-5′-monophosphate) from dUMP (2′-deoxyuridine-5′-monophosphate). However, ThyX proteins also act as NADPH oxidase by reacting directly with O2. In the present study we investigated the dynamic interplay between the substrates and their role in competing with this wasteful and potentially harmful oxidase reaction in catalytically efficient ThyX from Paramecium bursaria Chlorella virus-1. dUMP binding accelerates the O2-insensitive half-reaction between NADPH and FAD by over four orders of magnitude to ~30 s−1. Thus, although dUMP does not have a direct role in FAD reduction, any turnover with molecular O2 requires its presence. Inversely, NADPH accommodation accelerates dUMP binding ~3-fold and apparently precedes dUMP binding under physiological conditions. In the oxidative half-reaction, excess CH2H4folate (N5,N10-methylene-5,6,7,8-tetrahydrofolate) was found to re-oxidize FADH2 within 1 ms, thus very efficiently competing with FADH2 oxidation by O2 (1.5 s−1 under aerobic conditions). The resulting reaction scheme points out how the interplay between the fast reactions with the native substrates, although not rate-limiting for overall catalysis, avoids NADPH oxidase activity in aerobic micro-organisms, including many pathogens. These observations also explain why ThyX proteins are also present in aerobic micro-organisms.
Oleate promotes differentiation of chicken primary preadipocytes in vitro
Authors: Shang Zhouchun , Guo Lin , Wang Ning , Shi Hui , Wang Yuxiang , Li Hui
Published: January 2014

In addition to providing energy and constituting cell membrane, fatty acids also play an important role in adipocyte differentiation and lipid metabolism. As an important member of monounsaturated fatty acids, oleate, together with other components, is widely used to induce chicken preadipocyte differentiation. However, it is not clear whether oleate alone can induce chicken preadipocyte differentiation. In the present study, four different treatments were designed to test this question: basal medium, IDX [insulin, dexamethasone and IBMX (isobutylmethylxanthine)], oleate and IDX plus oleate. Cytoplasmic lipid droplet accumulation and mRNA expression for adipogenesis-related genes were monitored. After treatment of oleate on chicken preadipocytes, apparent lipid droplet formation and lipid accumulation were observed, accompanied by increasing expression of PPARγ (peroxisome proliferator-activated receptor-γ) and AFABP (adipocyte fatty acid-binding protein), but decreasing level of GATA2 (GATA-binding protein 2). In contrast, for cells cultured in the basal medium with or without IDX supplementation, lipid droplet barely occurred. These results suggest that exogenous oleate alone can act as an inducer of preadipocyte differentiation into adipocytes.
The proton injector for the accelerator facility of antiproton and ion research (FAIR)
Authors: Ullmann C. , Berezov R. , Fils J. , Chauvin N. , Delferriere O. , Hollinger R. , Kester O. , Vinzenz W.
Published: January 2014

The new international accelerator facility for antiproton and ion research (FAIR) at GSI in Darmstadt, Germany, is one of the largest research projects worldwide and will provide an antiproton production rate of 7 × 1010 cooled pbars per hour. This is equivalent to a primary proton beam current of 2 × 1016 protons per hour. For this request a high intensity proton linac (p-linac) will be built with an operating rf-frequency of 325 MHz to accelerate a 35 mA proton beam at 70 MeV, using conducting crossed-bar H-cavities. The repetition rate is 4 Hz with beam pulse length of 36 μs. The microwave ion source and low energy beam transport developed within a joint French-German collaboration GSI/CEA-SACLAY will serve as an injector of the compact proton linac. The 2.45 GHz ion source allows high brightness ion beams at an energy of 95 keV and will deliver a proton beam current of 100 mA at the entrance of the radio frequency quadrupole (RFQ) within an acceptance of 0.3π mm mrad (norm., rms).
Second order classical perturbation theory for atom surface scattering: Analysis of asymmetry in the angular distribution
Authors: Zhou Yun , Pollak Eli , Miret-Artés Salvador
Published: January 2014

A second order classical perturbation theory is developed and applied to elastic atom corrugated surface scattering. The resulting theory accounts for experimentally observed asymmetry in the final angular distributions. These include qualitative features, such as reduction of the asymmetry in the intensity of the rainbow peaks with increased incidence energy as well as the asymmetry in the location of the rainbow peaks with respect to the specular scattering angle. The theory is especially applicable to “soft” corrugated potentials. Expressions for the angular distribution are derived for the exponential repulsive and Morse potential models. The theory is implemented numerically to a simplified model of the scattering of an Ar atom from a LiF(100) surface.
Study of plasma meniscus and beam halo in negative ion sources using three dimension in real space and three dimension in velocity space particle in cell model
Authors: Nishioka S. , Miyamoto K. , Okuda S. , Goto I. , Hatayama A. , Fukano A.
Published: January 2014

Our previous study by two dimension in real space and three dimension in velocity space-particle in cell model shows that the curvature of the plasma meniscus causes the beam halo in the negative ion sources. The negative ions extracted from the periphery of the meniscus are over-focused in the extractor due to the electrostatic lens effect, and consequently become the beam halo. The purpose of this study is to verify this mechanism with the full 3D model. It is shown that the above mechanism is essentially unchanged even in the 3D model, while the fraction of the beam halo is significantly reduced to 6%. This value reasonably agrees with the experimental result.
Multi-cusp ion source for doping process of flat panel display manufacturing
Authors: Inouchi Yutaka , Matsumoto Takeshi , Dohi Shojiro , Tanii Masahiro , Takahashi Genki , Nishimura Ippei , Tatemichi Junichi , Konishi Masashi , Naito Masao
Published: January 2014

We developed a multi-cusp ion source for Nissin ion doping system iG5 which is used in low temperature poly-crystalline silicon processes for flat panel display (FPD) manufacturing. In this ion source, BF3 or PH3 diluted H2 plasmas are produced and large area ribbon ion beams are extracted. In general, ion ratio of B+ in BF3 plasma is much smaller than BF2+ in multi-cusp ion sources. We developed a new method to increase B+ ratio and obtained mass analyzed B+ target current of 130 mA. We employed newly improved multi-slot type electrodes for the beam extraction system and obtained stable beams with the uniformity of below 3%. In BF3 plasmas, several undesirable metal fluorides are produced in the plasma chamber and deposited on the electrode system, which cause glitches and poor beam uniformity. We introduce several cleaning methods.
An efficient approach to ab initio Monte Carlo simulation
Authors: Leiding Jeff , Coe Joshua D.
Published: January 2014

We present a Nested Markov chain Monte Carlo (NMC) scheme for building equilibrium averages based on accurate potentials such as density functional theory. Metropolis sampling of a reference system, defined by an inexpensive but approximate potential, was used to substantially decorrelate configurations at which the potential of interest was evaluated, thereby dramatically reducing the number needed to build ensemble averages at a given level of precision. The efficiency of this procedure was maximized on-the-fly through variation of the reference system thermodynamic state (characterized here by its inverse temperature β0), which was otherwise unconstrained. Local density approximation results are presented for shocked states of argon at pressures from 4 to 60 GPa, where—depending on the quality of the reference system potential—acceptance probabilities were enhanced by factors of 1.2–28 relative to unoptimized NMC. The optimization procedure compensated strongly for reference potential shortcomings, as evidenced by significantly higher speedups when using a reference potential of lower quality. The efficiency of optimized NMC is shown to be competitive with that of standard ab initio molecular dynamics in the canonical ensemble.
Finite temperature effects on the X-ray absorption spectra of lithium compounds: First-principles interpretation of X-ray Raman measurements
Authors: Pascal Tod A. , Boesenberg Ulrike , Kostecki Robert , Richardson Thomas J. , Weng Tsu-Chien , Sokaras Dimosthenis , Nordlund Dennis , McDermott Eamon , Moewes Alexander , Cabana Jordi , Prendergast David
Published: January 2014

We elucidate the role of room-temperature-induced instantaneous structural distortions in the Li K-edge X-ray absorption spectra (XAS) of crystalline LiF, Li2SO4, Li2O, Li3N, and Li2CO3 using high resolution X-ray Raman spectroscopy (XRS) measurements and first-principles density functional theory calculations within the eXcited electron and Core Hole approach. Based on thermodynamic sampling via ab initio molecular dynamics simulations, we find calculated XAS in much better agreement with experiment than those computed using the rigid crystal structure alone. We show that local instantaneous distortion of the atomic lattice perturbs the symmetry of the Li 1s core-excited-state electronic structure, broadening spectral line-shapes and, in some cases, producing additional spectral features. The excellent agreement with high-resolution XRS measurements validates the accuracy of our first-principles approach to simulating XAS, and provides both accurate benchmarks for model compounds and a predictive theoretical capability for identification and characterization of multi-component systems, such as lithium-ion batteries, under working conditions.
High energy density micro plasma bunch from multiple laser interaction with thin target
Authors: Xu Han , Yu Wei , Yu M. Y. , Cai H. B. , Luan S. X. , Yang X. H. , Yin Y. , Zhuo H. B. , Wang J. W. , Zhou C. T. , Murakami M. , Xu Z. Z.
Published: January 2014

Three-dimensional particle-in-cell simulation is used to investigate radiation-pressure driven acceleration and compression of small solid-density plasma by intense laser pulses. It is found that multiple impacts by presently available short-pulse lasers on a small hemispheric shell target can create a long-living tiny quasineutral monoenergetic plasma bunch of very high energy density.
Protonation effect on the electronic properties of 2-pyridone monomer, dimer and its water clusters: A theoretical study
Authors: Saed Behnaz , Omidyan Reza
Published: January 2014

The CC2 (second order approximate coupled cluster method) has been applied to investigate protonation effect on electronic transition energies of 2-pyridone (2PY), 2-pyridone dimer, and micro-solvated 2-pyridone (0-2 water molecules). The PE profiles of protonated 2-pyridone (2PYH+) as well as monohydrated 2PYH+ at the different electronic states have been investigated. The 1πσ* state in protonated species (2PYH+) is a barrier free and dissociative state along the O-H stretching coordinate. In this reaction coordinate, the lowest lying 1πσ* predissociates the bound S1(1ππ*) state, connecting the latter to a conical intersection with the S0 state. These conical intersections lead the 1ππ* state to proceed as predissociative state and finally direct the excited system to the ground state. Furthermore, in presence of water molecule, the 1πσ* state still remains dissociative but the conical intersection between 1πσ* and ground state disappears. In addition, according to the CC2 calculation results, it has been predicted that protonation significantly blue shifts the S1-S0 electronic transition of monomer, dimer, and microhydrated 2-pyridone.
Carrier interactions and porosity initiated reversal of temperature dependence of thermal conduction in nanoscale tin films
Authors: Kaul Pankaj B. , Prakash Vikas
Published: January 2014

Recently, tin has been identified as an attractive electrode material for energy storage/conversion technologies. Tin thin films have also been utilized as an important constituent of thermal interface materials in thermal management applications. In this regards, in the present paper, we investigate thermal conductivity of two nanoscale tin films, (i) with thickness 500 ± 50 nm and 0.45% porosity and (ii) with thickness 100 ± 20 nm and 12.21% porosity. Thermal transport in these films is characterized over the temperature range from 40 K–310 K, using a three-omega method for multilayer configurations. The experimental results are compared with analytical predictions obtained by considering both phonon and electron contributions to heat conduction as described by existing frequency-dependent phenomenological models and BvK dispersion for phonons. The thermal conductivity of the thicker tin film (500 nm) is measured to be 46.2 W/m-K at 300 K and is observed to increase with reduced temperatures; the mechanisms for thermal transport are understood to be governed by strong phonon-electron interactions in addition to the normal phonon-phonon interactions within the temperature range 160 K–300 K. In the case of the tin thin film with 100 nm thickness, porosity and electron-boundary scattering supersede carrier interactions, and a reversal in the thermal conductivity trend with reduced temperatures is observed; the thermal conductivity falls to 1.83 W/m-K at 40 K from its room temperature value of 36.1 W/m-K. In order to interpret the experimental results, we utilize the existing analytical models that account for contributions of electron-boundary scattering using the Mayadas-Shatzkes and Fuchs-Sondheimer models for the thin and thick films, respectively. Moreover, the effects of porosity on carrier transport are included using a previous treatment based on phonon radiative transport involving frequency-dependent mean free paths and the morphology of the nanoporous channels. The systematic modeling approach presented in here can, in general, also be utilized to understand thermal transport in semi-metals and semiconductor nano-porous thin films and/or phononic nanocrystals.
Dynamical simulation of electrostatic striped colloidal particles
Authors: Hagy Matthew C. , Hernandez Rigoberto
Published: January 2014

The static and dynamic properties of striped colloidal particles are obtained using molecular dynamics computer simulations. Striped particles with n = 2 to n = 7 stripes of alternating electric charge are modeled at a high level of detail through a pointwise (PW) representation of the particle surface. We also consider the extent to which striped particles are similar to comparable isotropically attractive particles—such as depletion attracting colloids—by modeling striped particles with an isotropic pair interaction computed by coarse-graining (CG) over orientations at a pair level. Surprisingly, the CG models reproduce the static structure of the PW models for a range of volume fractions and interaction strengths consistent with the fluid region of the phase diagram for all n. As a corollary, different n-striped particle systems with comparable pair affinities (e.g., dimer equilibrium constant) have similar static structure. Stronger pair interactions lead to a collapsed structure in simulation as consistent with a glass-like phase. Different n-striped particle systems are found to have different phase boundaries and for certain n's no glass-like state is observed in any of our simulations. The CG model is found to have accelerated dynamics relative to the PW model for the same range of fluid conditions for which the models have identical static structure. This suggests striped electrostatic particles have slower dynamics than comparable isotropically attractive colloids. The slower dynamics result from a larger number of long-duration reversible bonds between pairs of striped particles than seen in isotropically attractive systems. We also found that higher n-striped particles systems generally have slower dynamics than lower n-striped systems with comparable pair affinities.
Pattern formation in vibrated beds of dry and wet granular materials
Authors: Chuan Lim Eldin Wee
Published: January 2014

The Discrete Element Method was coupled with a capillary liquid bridge force model for computational studies of pattern formation in vibrated granular beds containing dry or wet granular materials. Depending on the vibration conditions applied, hexagonal, stripes, or cellular pattern was observed in the dry vibrated granular bed. In each of these cases, the same hexagonal, stripes, or cellular pattern was also observed in the spatial distribution of the magnitudes of particle-particle collision forces prior to the formation of the corresponding actual pattern in physical distributions of the particles. This seemed to suggest that the pattern formation phenomenon of vibrated granular bed systems might be the result of a two-dimensional Newton's cradle effect. In the presence of a small amount of wetness, these patterns were no longer formed in the vibrated granular beds under the same corresponding set of vibration conditions. Despite the relatively much weaker capillary forces arising from the simulated liquid bridges between particles compared with particle-particle collision forces, the spatial distributions of these collision forces, physical distributions of particles, as well as time profiles of average collision forces were altered significantly in comparison with the corresponding distributions and profiles observed for the dry vibrated granular beds. This seemed to suggest the presence of a two-dimensional Stokes’ cradle effect in these wet vibrated granular bed systems which disrupted the formation of patterns in the wet granular materials that would have been observed in their dry counterparts.
Time- and frequency-dependent model of time-resolved coherent anti-Stokes Raman scattering (CARS) with a picosecond-duration probe pulse
Authors: Stauffer Hans U. , Miller Joseph D. , Slipchenko Mikhail N. , Meyer Terrence R. , Prince Benjamin D. , Roy Sukesh , Gord James R.
Published: January 2014

The hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering (fs/ps CARS) technique presents a promising alternative to either fs time-resolved or ps frequency-resolved CARS in both gas-phase thermometry and condensed-phase excited-state dynamics applications. A theoretical description of time-dependent CARS is used to examine this recently developed probe technique, and quantitative comparisons of the full time–frequency evolution show excellent accuracy in predicting the experimental vibrational CARS spectra obtained for two model systems. The interrelated time- and frequency-domain spectral signatures of gas-phase species produced by hybrid fs/ps CARS are explored with a focus on gas-phase N2 vibrational CARS, which is commonly used as a thermometric diagnostic of combusting flows. In particular, we discuss the merits of the simple top-hat spectral filter typically used to generate the ps-duration hybrid fs/ps CARS probe pulse, including strong discrimination against non-resonant background that often contaminates CARS signal. It is further demonstrated, via comparison with vibrational CARS results on a time-evolving solvated organic chromophore, that this top-hat probe-pulse configuration can provide improved spectral resolution, although the degree of improvement depends on the dephasing timescales of the observed molecular modes and the duration and timing of the narrowband final pulse. Additionally, we discuss the virtues of a frequency-domain Lorentzian probe-pulse lineshape and its potential for improving the hybrid fs/ps CARS technique as a diagnostic in high-pressure gas-phase thermometry applications.