bluuebunny/crossref_metadata_2025 huggingface dataset:
Noninvasive Monopolar Capacitive‐Coupled Radiofrequency for the Treatment of Pain Associated With Lateral Elbow Tendinopathies: 1‐Year Follow‐up
Authors: Weber Tobias , Kabelka Bernd
Published: February 2012

Objective

To evaluate noninvasive monopolar capacitive‐coupled radiofrequency (mcRF) for the treatment of pain associated with lateral elbow tendinopathies.

Design

Prospective, single‐center, single‐arm, 1‐year follow‐up.

Setting

Private sports medicine practice.

Participants

Thirty‐nine consecutive patients with diagnosis of lateral elbow tendinopathy (including 3 bilateral cases, for a total of 42 elbows) participated in the study. All patients had been unsuccessfully treated with a variety of nonoperative therapies (eg, nonsteroidal anti‐inflammatory drugs, corticosteroid injections, and braces) for at least 3 months before they were enrolled in the study.

Intervention

Patients were treated with mcRF technology in the office without local anesthetic or any particular preparation. Anatomic landmarks and careful determination of the most tender point defined the area treated; rapid and precise mcRF pulses were delivered covering the area in a staggered fashion; and 10 additional pulses were delivered directly to the point of maximum tenderness (total of 100 pulses). Patients returned to activities of daily living without restriction and were instructed to avoid nonsteroidal anti‐inflammatory drugs and/or ice over the treated area. Physical therapy or other treatment modalities were disallowed.

Results

The presence of pain before enrollment ranged from 15 weeks to 2 years (average, 32 weeks). Visual analog scores at rest, with regular activity, and with triggering events were gathered at 3, 6, and 12 months. The Nirschl Tennis Elbow Questionnaire and patient satisfaction also were used to evaluate study outcomes. Follow‐up average was 423 days (range, 330‐487 days). On the basis of the study's multifactorial success criteria, 81% of participants had successful outcomes. Furthermore, 89% of the patients who completed the study were completely or moderately satisfied with the outcome.

Conclusions

Outcomes of this study suggest that noninvasive mcRF may have a role in the treatment of pain associated with lateral elbow tendinopathies. The noninvasive nature of the procedure and the safety and efficacy suggested by this study may offer significant advantages over current treatment alternatives. Further research in the form of a randomized clinical trial is recommended.
Positive Effects of a Musculoskeletal Pain Rehabilitation Program Regardless of Pain Duration or Diagnosis
Authors: Persson Elisabeth , Lexell Jan , Eklund Mona , Rivano‐Fischer Marcelo
Published: February 2012

Objectives

To investigate how sociodemographic and clinical factors are associated with psychosocial functioning and disability at admission to a musculoskeletal pain rehabilitation program and at 1‐year follow‐up.

Design

A cohort pre‐post study.

Setting

A University hospital specialized pain rehabilitation unit.

Participants

Five hundred nine participants with musculoskeletal pain (neck disorders, 29%; fibromyalgia, 24%; low back pain, 24%; myalgia, 14%; and other pain diagnoses, 8%).

Intervention

A 5‐week outpatient, group‐based, and goal‐oriented comprehensive musculoskeletal interdisciplinary pain rehabilitation program based on cognitive behavioral principles.

Main Outcome Measures

The Multidimensional Pain Inventory (MPI), the Disability Rating Index (DRI), and forms including sociodemographic factors (gender, age, ethnicity, marital status, educational level, and vocational situation) and clinical factors (pain duration and pain diagnoses). Data were analyzed with multivariate logistic regression.

Results

At admission, factors associated with more positive scores on the MPI were being older than 40 years, being at work, being Nordic born, attainment of a higher educational level, and a diagnosis of fibromyalgia (compared with a neck disorder) (P < .05). Being at work and a diagnosis of fibromyalgia (compared with low back pain) were associated with more positive scores on the DRI (P < .05). On the basis of cut points for clinically important change on the MPI, participants rated themselves as most improved on the Affective Distress (52%), Life Control (49%), and Pain Severity (43%) subscales, and on the DRI index, the improvement rate was 22%. At the 1‐year follow‐up, neither sociodemographic nor clinical factors were associated with clinically important improvements of the MPI and the DRI, but younger age was related to deteriorations in pain severity.

Conclusions

The lack of an association between sociodemographic and clinical factors and psychosocial functioning and disability at a 1‐year follow‐up after a musculoskeletal pain rehabilitation program suggests that the program was effective regardless of the participants' initial characteristics, except for age. The changes at the 1‐year follow‐up indicate that the program influenced the participants' psychosocial functioning more than their perception of disability.
A VARIATIONAL McSHANE INTEGRAL CHARACTERISATION OF THE WEAK RADON–NIKODYM PROPERTY
Authors: KALIAJ SOKOL BUSH
Published: February 2012

We present a characterisation of Banach spaces possessing the weak Radon–Nikodym property in terms of finitely additive interval functions whose McShane variational measures are absolutely continuous with respect to Lebesgue measure.
Objective predictors of delayed-onset post-traumatic stress disorder occurring after military discharge
Authors: Brewin C. R. , Andrews B. , Hejdenberg J. , Stewart L.
Published: February 2012

Background

Post-traumatic stress disorder (PTSD) that develops after military personnel have been discharged may lead to severe impairment. We investigated whether personnel who develop PTSD after discharge can be identified by independent evidence of internalizing signs such as depression or of externalizing signs such as disciplinary offences while still serving.

Method

Veterans in receipt of a war pension who only developed PTSD post-discharge were compared with matched veterans who developed PTSD in service or never suffered from PTSD. Contemporaneous medical and personnel records were searched for objective evidence of internalizing and externalizing disorder.

Results

Service personnel who developed PTSD post-discharge were indistinguishable from controls with no PTSD on their psychiatric presentation in service. Those with post-discharge PTSD had significantly more disciplinary offences, specifically absence without leave, disobedience, and dishonesty, than the no-PTSD group, and this excess of offences was present before any exposure to trauma.

Conclusions

This is the first study to find objective evidence independent of self-report for the claimed link between externalizing disorder and vulnerability to PTSD. Early signs of externalizing disorders may play an important role in helping to identify service personnel at risk of PTSD after military discharge.
ADAPTIVE LASSO-TYPE ESTIMATION FOR MULTIVARIATE DIFFUSION PROCESSES
Authors: De Gregorio Alessandro , Iacus Stefano M.
Published: February 2012

The least absolute shrinkage and selection operator (LASSO) is a widely used statistical methodology for simultaneous estimation and variable selection. It is a shrinkage estimation method that allows one to select parsimonious models. In other words, this method estimates the redundant parameters as zero in the large samples and reduces variance of estimates. In recent years, many authors analyzed this technique from a theoretical and applied point of view. We introduce and study the adaptive LASSO problem for discretely observed multivariate diffusion processes. We prove oracle properties and also derive the asymptotic distribution of the LASSO estimator. This is a nontrivial extension of previous results by Wang and Leng (2007,Journal of the American Statistical Association, 102(479), 1039–1048) on LASSO estimation because of different rates of convergence of the estimators in the drift and diffusion coefficients. We perform simulations and real data analysis to provide some evidence on the applicability of this method.
Aortic stiffness and flow-mediated dilatation in normotensive offspring of parents with hypertension
Authors: Evrengul Harun , Tanriverdi Halil , Kilic Ismail D. , Dursunoglu Dursun , Ozcan Emin E. , Kaftan Asuman , Kilic Mustafa
Published: February 2012

Objectives

Although hypertension has been shown to be one of the most important risk factors for atherosclerosis, data about the presence of subclinical atherosclerosis in normotensive offspring with parental history of hypertension are scarce. Accordingly, the current study was designated to evaluate flow-mediated dilatation and aortic stiffness, which are early signs of atherosclerosis in young subjects with parental history of hypertension.

Methods

A total of 102 healthy, non-obese subjects in the age group of 18–22 years were included in this study and divided into two groups. The first group included 70 offspring of hypertensive parents and the second group included 70 offspring of normotensive parents as controls. In all subjects, endothelium-dependent and endothelium-independent vasodilatation of the brachial artery and aortic elastic parameters were investigated using high-resolution Doppler echocardiography.

Results

Offspring of hypertensive parents demonstrated higher values of aortic stiffness (7.1 plus or minus 1.88 and 6.42 plus or minus 1.56, respectively) but lower distensibility (9.47 plus or minus 1.33 and 11.8 plus or minus 3.36 square centimetres per dyne per 106) and flow-mediated dilatation (4.57 plus or minus 1.3 versus 6.34 plus or minus 0.83 percent, p equals 0.0001, respectively) than offspring of hypertensive parents.

Conclusion

We observed blunted endothelium-dependent dilatation and aortic stiffness in offspring of hypertensive parents compared with offspring of hypertensive parents. This is evident in the absence of overt hypertension and other diseases, suggesting that parental history of hypertension is a risk for subclinical atherosclerosis and it may contribute to the progression to hypertension and overt atherosclerosis in later life.
Confronting the Challenge of Energy Governance
Authors: Gunningham Neil
Published: February 2012

There is a compelling argument for developing a low carbon emissions trajectory to mitigate climate change and for doing so urgently. What is needed is a transformation of the energy sector and an ‘energy revolution’. Such a revolution can only be achieved through effective energy governance nationally, regionally, and globally. But frequently such governance is constrained by the tensions between energy security, climate change mitigation and energy poverty. At national level, there is a chasm between what is needed and what governments do ‘on the ground’, while regionally and globally, collective action challenges have often presented insurmountable obstacles. The article examines what forms of energy law, regulation and governance are most needed to overcome these challenges and whether answers are most likely to be found in hierarchy, markets, or networks.
Stressbewältigung von Kindern und Jugendlichen in Deutschland und der Türkei
Authors: Kohlmann Carl-Walter , Eschenbeck Heike , Heim-Dreger Uwe , Tasdaban Elif
Published: February 2012

Zusammenfassung. Es besteht die Annahme, dass in eher kollektivistisch orientierten asiatischen Kulturkreisen weniger soziale Unterstützung in Stresssituationen gesucht wird als etwa in individualistischen europäischen. Diese Hypothese wurde auf Basis einer Befragung von Kindern und Jugendlichen der 4. bis 8. Klasse (Alter: 9 bis 16 Jahre) in Deutschland (n = 1240) und der Türkei (n = 473) zur Suche nach sozialer Unterstützung als Stressbewältigungsstrategie in einer sozialen und einer akademischen Stresssituation („Streit mit Freund bzw. Freundin”, „zu viele Hausaufgaben”) getestet. Entgegen der Erwartung resultierte kein genereller kultureller Unterschied in der Suche nach sozialer Unterstützung. Für den akademischen Stressor berichten türkische Kinder und Jugendliche gegenüber deutschen sogar vermehrt Suche nach sozialer Unterstützung. Ferner zeigte sich, dass Geschlechtsunterschiede in der Suche nach sozialer Unterstützung, mit höheren Werten für Mädchen, in Deutschland stärker ausgeprägt sind als in der Türkei. Gesundheitspsychologische Implikationen werden diskutiert.
Die Entwicklungsbedingungen der Adaptivität
Authors: Meyer Tamara , Greve Werner
Published: February 2012

Zusammenfassung. Obwohl die Entwicklung intrapersonaler Selbstregulations- und Bewältigungsprozesse im Erwachsenenalter seit längerem theoretisch elaboriert und empirisch differenziert untersucht wird, ist bislang über die Entwicklungsbedingungen und -voraussetzungen von adaptiven Regulationsfähigkeiten sowie potenziellen Früh- und Vorformen im Kindes- und Jugendalter wenig bekannt. Vorliegende Ansätze und Studien zu Bewältigungsformen in Kindheit und Jugend konzentrieren sich meist auf weiter gefasste Facetten kindlicher Regulationskompetenz und sind bislang kaum mit Bezug auf erwachsene Copingreaktionen und die verbindenden Entwicklungsprozesse konzipiert. Das hier dargestellte Forschungsprogramm greift dieses Desiderat auf und soll erste Antworten auf ausgewählte Fragen nach den Entwicklungsbedingungen der individuellen Adaptivität liefern. Mit Bezug auf das Zwei-Prozess-Modell der Entwicklungsregulation im Erwachsenenalter ( Brandtstädter & Rothermund, 2002 ) werden in zwei umfangreichen Studien verschiedene soziale, kognitive und affektive Entwicklungsbedingungen der Akkommodation im Jugendalter untersucht. Im Anschluss an diese Befunde wird abschließend ein erstes Entwicklungsmodell akkommodativer Regulationskomptenz vorgeschlagen.
Schmerzkatastrophisieren bei Kindern und Jugendlichen
Authors: Hermann Christiane , Hohmeister Johanna
Published: February 2012

Zusammenfassung. Zahlreiche Untersuchungen sowohl bei Erwachsenen wie bei Kindern und Jugendlichen haben gezeigt, dass Schmerzkatastrophisieren im Vergleich zu anderen Schmerzbewältigungsstrategien die größte klinische Relevanz besitzt. Unter Schmerzkatastrophisieren versteht man die überdauernde Tendenz, Schmerz als ein besonders aversiv-bedrohliches Ereignis zu erleben, dem man mehr oder weniger hilflos ausgesetzt ist und über das man wiederholt und intensiv grübelt. Um die Maladaptivität von Schmerzkatastrophisieren nachvollziehbar zu machen, werden in dieser Übersicht verschiedene theoretische Modelle (Aufmerksamkeitsmodell, Bewertungsmodell, Kommunikationsmodell) und ihre Implikationen speziell für das Verständnis des Schmerzerlebens bei Kindern und Jugendlichen vorgestellt. Außerdem werden vorhandene Fragebogeninstrumente beschrieben und miteinander verglichen. Ein besonderes Augenmerk liegt dabei auf Instrumenten, die im deutschsprachigen Raum einsetzbar sind. Die klinische Relevanz von Schmerzkatastrophisieren wird schließlich exemplarisch anhand der Zusammenhänge mit der erlebten Schmerzintensität, der funktionalen Beeinträchtigung und der Schmerzchronifizierung aufgezeigt.
WITHDRAWN: Influence of Porous Media Heterogeneity on NAPL Dissolution Fingering and Upscaled Mass Transfer
Authors: Seyedabbasi M.A. , Farthing M.W. , Imhoff P.T. , Miller C.T.
Published: February 2012

The utility of existing models for describing upscaled mass transfer from non‐aqueous phase liquid (NAPL) were examined when preferential dissolution pathways form in NAPL‐contaminated zones. Such models are needed because the coarse discretizations often used in simulators cannot capture the details of local‐scale preferential dissolution pathways.

Laboratory experiments were conducted in two well‐characterized, heterogeneous packings that differed only in the correlation lengths of the permeability field. Experimental results were used to validate a numerical simulator for capturing the growth of centimeter‐scale preferential NAPL dissolution patterns. Using data from these experiments and simulations, three methods for upscaling the mass transfer rate coefficient for NAPL dissolution [Imhoff et al., 2003; Saenton and Illangasekare, 2007; Christ et al., 2006] and an equilibrium stream tube model for predicting contaminant flux [Basu et al., 2008] were evaluated. These models account for the influence of dissolution fingering [Imhoff et al., 2003] or NAPL architecture [Saenton and Illangasekare, 2007; Christ et al., 2006; Basu et al., 2008] on contaminant flux from NAPL source zones, and were applied here to local‐scale preferential NAPL dissolution. When the correlation length of permeability perpendicular to the mean water flow direction was 6.0 cm, greater than the scale of the dissolution fingers, only 4.2% of the NAPL resided in pools. Dissolution fingers formed in this experiment and all models predicted effluent concentrations with similar accuracy, with root mean square errors (RMSE's) between 0.03 and 0.05. When the correlation scale was smaller (1.0 cm), 31.3% of the NAPL was in pools and preferential dissolution pathways were dominated by channeling, preferential dissolution caused by spatial variations in aqueous phase velocity and NAPL dissolution rates. For this experiment all models performed poorly, with RMSEs between 0.12 and 0.35. Dissolution fingering was important when the permeability correlation length was sufficiently large that dissolution finger formation was not disrupted and NAPL pools were not dominant.
Warmth and Competence: Stereotypes of the Elderly Among Young Adults and Older Persons in Brazil
Authors: de Paula Couto Maria Clara Pinheiro , Koller Sílvia Helena
Published: February 2012

According to the Stereotype Content Model, out-group stereotypes vary on the dimensions of warmth and competence ( Fiske, Cuddy, Glick, & Xu, 2002 ). Studies in other cultural settings have shown that elderly persons are often viewed as warm but not very competent. The present study was designed to examine societal stereotypes of the elderly among 118 Brazilians of different ages. Participants reported that Brazilian society views the elderly as more warm than competent. With regard to competence there were age-related differences with older persons seeing the elderly as more competent than did younger persons. Interpretations in terms of in-group preference and developmental changes are put forth.
The Skeletal Muscle Wnt Pathway May Modulate Insulin Resistance and Muscle Development in a Diet‐Induced Obese Rat Model
Authors: Zhou Dan , Strakovsky Rita S. , Zhang Xiyuan , Pan Yuan‐Xiang
Published: February 2012

The Wnt signaling pathway is involved in lipid metabolism and obesity development. Skeletal muscle, a pivotal tissue for metabolism, is regulated by the Wnt signaling. However, little is known of this pathway's involvement in insulin sensitivity and myogenesis in animals. The current study focused on the potential role of Wnt signaling in insulin sensitivity and myogenic events and its further impact on intramuscular fat accumulation. Obesity resistant (OR) and obesity prone (OP) rats were fed a high‐fat (HF, 45% kcal fat) diet for 13 weeks. Body weight and circulating triglyceride (TG) were measured and gastrocnemius muscle was collected for analysis of gene expression and protein amount. OP rats had higher body weight and blood TG than OR, and our study demonstrated that the skeletal muscle of OR and OP rats had different levels of β‐catenin, which also corresponded to the expression of Wnt downstream genes. The expression of insulin receptor substrate (IRS) was significantly lower in OP than OR skeletal muscle, as was the protein amount of phosphorylated Akt, myocyte enhancer factor‐2 (MEF2), and GLUT4. Expression of Myogenic regulatory factor (Myf) 5 and Myf3 (MyoD) were decreased significantly in OP skeletal muscle when compared to OR. Additionally, intramuscular fat was higher in OP than in OR rats. Thus, we propose that the differential Wnt signaling in the skeletal muscle of OR and OP rats is highly likely associated with the differences in insulin sensitivity and myogenic capability in these two strains.
The ligand specificity of the G-protein-coupled receptor GPR34
Authors: Ritscher Lars , Engemaier Eva , Stäubert Claudia , Liebscher Ines , Schmidt Philipp , Hermsdorf Thomas , Römpler Holger , Schulz Angela , Schöneberg Torsten
Published: February 2012

Lyso-PS (lyso-phosphatidylserine) has been shown to activate the Gi/o-protein-coupled receptor GPR34. Since in vitro and in vivo studies provided controversial results in assigning lyso-PS as the endogenous agonist for GPR34, we investigated the evolutionary conservation of agonist specificity in more detail. Except for some fish GPR34 subtypes, lyso-PS has no or very weak agonistic activity at most vertebrate GPR34 orthologues investigated. Using chimaeras we identified single positions in the second extracellular loop and the transmembrane helix 5 of carp subtype 2a that, if transferred to the human orthologue, enabled lyso-PS to activate the human GPR34. Significant improvement of agonist efficacy by changing only a few positions strongly argues against the hypothesis that nature optimized GPR34 as the receptor for lyso-PS. Phylogenetic analysis revealed several positions in some fish GPR34 orthologues which are under positive selection. These structural changes may indicate functional specification of these orthologues which can explain the species- and subtype-specific pharmacology of lyso-PS. Furthermore, we identified aminoethyl-carbamoyl ATP as an antagonist of carp GPR34, indicating ligand promiscuity with non-lipid compounds. The results of the present study suggest that lyso-PS has only a random agonistic activity at some GPR34 orthologues and the search for the endogenous agonist should consider additional chemical entities.
A new highly sensitive broadband ferromagnetic resonance measurement system with lock-in detection
Authors: Beguhn S. , Zhou Ziyao , Rand S. , Yang X. , Lou J. , Sun N. X.
Published: February 2012

RF/microwave magnetic measurement systems can be categorized into broadband or narrowband systems. Narrowband systems utilize high Q cavities for magnetic material characterizations such as electron paramagnetic resonance or electron spin resonance. Example broadband characterization systems are permeameters or pulsed inductive magnetometers. Narrowband measurement systems have high sensitivity but limited bandwidth whereas broadband systems suffer from lower sensitivity. In particular, it has been challenging to precisely measure weak magnetization, high anisotropy and high ferromagnetic resonance linewidth across a broad bandwidth. In this work, we report a new highly sensitive broadband resonance measurement system with lock-in detection utilizing a broadband transmission line. The frequency of the RF source is swept while the magnetic field is fixed. The resulting curve of dP/dH versus f is similar to the dP/dH versus H curve from conventional narrowband magnetic measurement system. The imaginary component of magnetic susceptibility χ" is calculated by the equation of χ"(f)=C∫(dP/dH*dH/df)df, in which C is a constant and dH/df is determined from the Kittel equation for magnetic films. Broadband measurements of sputtered low-moment lossy NiCr (4πMs=1100 G) as well as NiFe (4πMs=11000 G) were taken and compared with conventional broadband measurement using a network analyzer.
An active resonator based on magnetic films for near field microwave microscopy
Authors: Qureshi Naser , Kolokoltsev Oleg V. , Ordoñez-Romero César L. , López-Maldonado Guillermo
Published: February 2012

An active resonator perturbation method is introduced as a sensitive and versatile way to probe material properties in near field microwave microscopy. An active ring microwave oscillator based on magnetostatic excitations in a yittrium iron garnet thin film has been developed with a coaxial near field probe connected directly to the resonator ring. The probe tunes the resonator’s emission frequency, and the high Q-factor of the magnetostatic oscillations allows for a very sensitive spatially resolved probe of surface impedance and material properties with a much larger dynamic range than conventional resonant probes for microwave microscopy.
Anisotropy study of garnet films grown over substrates populated with gold nanoparticles
Authors: Lang G. , Bowen D. , Hung L. , Krafft C. , Mayergoyz I.
Published: February 2012

Anisotropy of garnet films grown by liquid phase epitaxy (LPE) over (100)-oriented garnet substrates populated with gold nanoparticles is studied. The results of ferromagnetic resonance (FMR) and optical hysteresis loop measurements as well as optical images of domain structures of LPE-grown garnet films are presented and discussed.
The magnetic Curie temperature and exchange coupling between cations in tetragonal spinel oxide Mn2.5M0.5O4 (M = Co, Ni, Mn, Cr, and Mg) films
Authors: Kuo K. , Cheng C. W. , Chern G.
Published: February 2012

Mn3O4 is a Jahn-Taller tetragonal ferrite that has a relatively low Curie temperature (Tc) of ∼43 K due to weak coupling between the canting spins. In this study, we fabricated a series of 100-nm-thick Mn2.5M0.5O4 (M = Co, Ni, Mn, Cr, and Mg) films via oxygen-plasma-assisted molecular beam epitaxy and measured the structural and magnetic properties of these films. These films show single phase quality, and the c-axis lattice parameter of pure Mn3O4 is 0.944 nm, with a c/a ratio ∼1.16, consistent with the bulk values. The replacement of Mn by M (M = Co, Ni, Cr, and Mg) changes the lattice parameters, and the c/a ratio varies between 1.16 and 1.06 depending upon the cation distribution of the films. The magnetic Curie temperatures of these films also vary in the range of 25–66 K in that Ni and Co enhance the Tc whereas Mg reduces the Tc (Cr shows no effect on the Tc). These changes to the Tc are related to both the element electronic state and the cation distributions in these compounds. As a non-collinear spin configuration can induce electrical polarization, the present study provides a systematic way to enhance the magnetic transition temperature in tetragonal spinel ferrites.
Research and development of H− ion source and low energy beam transport for a kaon-neutrino factory
Authors: Ji Q. , Staples J. , Sy A. , Schenkel T. , Li D.
Published: February 2012

A baseline H− ion source and low energy beam transport (LEBT) system have been identified for Project X. The filament-discharge H− ion source has been fabricated by D-Pace, Inc. and is now in operation at LBNL. The source is capable of delivering over 10 mA of H− beam in cw operation with normalized 4 rms emittances less than 0.7 π mm mrad. A two-solenoid magnetic lens LEBT system has been design. The design has been validated with simulations of beam transport for 5 mA 30 keV H− beams using various simulation codes.
Experimental electron energy distribution function investigation at initial stage of electron cyclotron resonance discharge
Authors: Golubev S. V. , Izotov I. V. , Mansfeld D. A. , Semenov V. E.
Published: February 2012

Experimental investigation is undertaken to study formation of electron energy distribution function (EEDF) at the initial stage of electron cyclotron resonance (ECR) discharge inside magnetic mirror trap. In experiment, where discharge was initiated by high power radiation of gyrotron operated in the mm-wavelength range, electrons were revealed to leave the trap having EEDF be quite different from Maxwellian one. Specifically, the EEDF was found to decrease slowly with energy up to 400–500 keV and drops abruptly further. The possible physical mechanisms are discussed to explain losses of high energy electrons from the trap and a limitation of their energy.
Shunting arc plasma source for pure carbon ion beam
Authors: Koguchi H. , Sakakita H. , Kiyama S. , Shimada T. , Sato Y. , Hirano Y.
Published: February 2012

A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA/mm2 at the peak of the pulse.
Effect of non-uniform electron energy distribution function on plasma production in large arc driven negative ion source
Authors: Shibata T. , Koga S. , Terasaki R. , Inoue T. , Dairaku M. , Kashiwagi M. , Taniguchi M. , Tobari H. , Tsuchida K. , Umeda N. , Watanabe K. , Hatayama A.
Published: February 2012

Spatially non-uniform electron energy distribution function (EEDF) in an arc driven negative ion source (JAEA 10A negative ion source: 10 A NIS) is calculated numerically by a three-dimensional Monte Carlo kinetic model for electrons to understand spatial distribution of plasma production (such as atomic and ionic hydrogen (H0/H+) production) in source chamber. The local EEDFs were directly calculated from electron orbits including electromagnetic effects and elastic/inelastic collision forces. From the EEDF, spatial distributions of H0/H+ production rate were obtained. The results suggest that spatial non-uniformity of H0/H+ productions is enhanced by high energy component of EEDF.
Optimization of gas utilization efficiency for short-pulsed electron cyclotron resonance ion source
Authors: Izotov I. V. , Skalyga V. A. , Zorin V. G.
Published: February 2012

Numerical analysis of 6He atoms utilizing efficiency in the ion source with powerful gyrotron heating is performed in present work using zero-dimensional balanced model of ECR discharge in a magnetic trap. Two ways of creation of ion source with high gas utilization efficiency (up to 60%–90%) are suggested.
Radio frequency discharge with control of plasma potential distribution
Authors: Dudnikov Vadim , Dudnikov A.
Published: February 2012

A RF discharge plasma generator with additional electrodes for independent control of plasma potential distribution is proposed. With positive biasing of this ring electrode relative end flanges and longitudinal magnetic field a confinement of fast electrons in the discharge will be improved for reliable triggering of pulsed RF discharge at low gas density and rate of ion generation will be enhanced. In the proposed discharge combination, the electron energy is enhanced by RF field and the fast electron confinement is improved by enhanced positive plasma potential which improves the efficiency of plasma generation significantly. This combination creates a synergetic effect with a significantly improving the plasma generation performance at low gas density. The discharge parameters can be optimized for enhance plasma generation with acceptable electrode sputtering.
Technical use of compact micro-onde devices
Authors: Sortais P. , Lamy T. , Médard J. , Angot J. , Sudraud P. , Salord O. , Homri S.
Published: February 2012

Due to the very small size of a COMIC (Compact MIcrowave and Coaxial) device [P. Sortais, T. Lamy, J. Médard, J. Angot, L. Latrasse, and T. Thuillier, Rev. Sci. Instrum. 81, 02B31 (2010)10.1063/1.3272878] it is possible to install such plasma or ion source inside very different technical environments. New applications of such a device are presented, mainly for industrial applications. We have now designed ion sources for highly focused ion beam devices, ion beam machining ion guns, or thin film deposition machines. We will mainly present new capabilities opened by the use of a multi-beam system for thin film deposition based on sputtering by medium energy ion beams. With the new concept of multi-beam sputtering (MBS), it is possible to open new possibilities concerning the ion beam sputtering (IBS) technology, especially for large size deposition of high uniformity thin films. By the use of multi-spots of evaporation, each one corresponding to an independent tuning of an individual COMIC ion source, it will be very easy to co-evaporate different components.
Analysis of the H− ion emissive surface in the extraction region of negative ion sources
Authors: Kameyama N. , Fukuyama T. , Wada S. , Kuppel S. , Tsumori K. , Nakano H. , Hatayama A. , Miyamoto K. , Fukano A. , Bacal M.
Published: February 2012

To understand the plasma characteristics in the extraction region of negative H− sources is very important for the optimization of H− extraction from the sources. The profile of plasma density and electrostatic potential in the extraction region with and without extraction grid voltage are analyzed with a 2D particle in cell modeling of the NIFS-RD H− sources. The simulation results make clear the physical process forming a double ion plasma layer (which consists only of positive H+ and negative H− ions) recently observed in the Cs-seeded experiments of the NIFS-R&D source in the vicinity of the extraction hole and the plasma grid. The results also give a useful insight into the formation mechanism of the plasma meniscus and the H− extraction process for such double ion plasma.
High frequency characteristics of FeCoAlO thin films fabricated with asymmetric target at different Ar gas flow rates
Authors: Zheng Fu , Luo Feilong , Lou Yuanfu , Wang Ying , Bai Jianmin , Wei Dan , Liu Xiaoxi , Wei Fulin
Published: February 2012

FeCoAlO thin films with good soft magnetic properties were fabricated by using RF magnetron sputtering. In order to obtain good high-frequency performance, the in-plane uniaxial anisotropy was tuned by combining the effects of in situ magnetic field and the gradient of Al–O concentration. The composition gradient was controlled by using an asymmetric target and different Ar gas flow rates changing from 5 sccm to 17.5 sccm. It was found that at the range of Ar gas flow rate from 7.5 sccm to 15 sccm, the films showed an excellent high-frequency performance: the resonance frequency was beyond 3.0 GHz and the real permeability μ′ had a high value of ∼200 at low-frequency side. In particular, the film prepared at the Ar gas flow rate of 15 sccm showed a resonance frequency of 4.0 GHz. Large resonance frequency can be attributed to the high in-plane uniaxial anisotropy field which was induced by stress and the external magnetic field. The high values of permeability and resonance frequency enable the FeCoAlO thin films to be one of the important candidates for microwave applications.
Excessive grain boundary conductivity of spin-spray deposited ferrite/non-magnetic multilayer
Authors: Xing Yun , Myers J. , Obi Ogheneyunume , Sun Nian X. , Zhuang Yan
Published: February 2012

Magnetic materials with a high self-biased ferromagnetic resonance (FMR) frequency and low electrical conductivity hold great potential for RF/microwave devices. In this work, ferrite film consisting of Fe3O4 (1.2 μm)/photoresist (60 nm)/Fe3O4 (1.2 μm) was deposited at 90 °C via spin spray deposition. Broadband impedance imaging with nanometer spatial resolution was recorded by using scanning microwave microscopy. Compared to a reference sample, it turned out that the grain boundary appeared to be more conductive than the grain.
The absorption property of single crystal LuBiIG garnet film in terahertz band
Authors: Yang Qing-Hui , Zhang Huai-Wu , Wen Qi-Ye , Liu Ying-Li
Published: February 2012

In this paper, a hypothesis has been brought forward that the materials with low propagation loss in both optical and microwave band may exhibit good performance in terahertz (THz) band because THz wave band interspaces those two wave bands. Several kinds of single crystal garnet films were investigated and we found that the Lu2.1Bi0.9Fe5O12 film which grows by liquid phase epitaxy (LPE) from PbO-free flux has the best absorption properties in both microwave and optical band. In THz range, our hypothesis is well confirmed by a THz-TDS measurement which shows that the absorption coefficient of LuBiIG film is 0.05–0.3 cm−1, and the minimum value appears at 2.24 THz.
Al doped Ba hexaferrite (BaAlxFe12-xO19) thin films on Pt using metallo-organic decomposition
Authors: Harward I. , Nie Yan , Gardner A. , Reisman L. , Celinski Z.
Published: February 2012

We grew a series of aluminum-substituted M-type barium hexaferrite (BaAlxFe12-xO19) thin films on a Pt (111) template and Si wafer using metallo-organic decomposition technique. We varied the composition from x = 0 to x = 2 with 0.25 step increments. X-ray diffraction patterns confirm highly textured c-axis polycrystalline films while atomic force microscope measurements allow us to estimate the lateral grain sizes which range from 0.2-1 micron depending on Al content. The microwave properties of these films were studied using a broadband ferromagnetic resonance spectrometer from 35 to 70 GHz. The measured out of plane effective anisotropy field increases in a nearly linear fashion with increasing Al concentration, between 12.8 kOe for x = 0 and 25 kOe for x = 2. The measured ferromagnetic resonance linewidths were relatively low, on the order of 150–300 Oe for compositions below x = 1, increasing significantly up to 800 Oe for x = 2. The easy axis magnetic hysteresis loops exhibit high squareness.
Potential of sub-micron-sized Fe-Co particles for antenna applications
Authors: Kodama Daisuke , Shinoda Kozo , Kasuya Ryo , Doi Masaaki , Tohji Kazuyuki , Jeyadevan Balachandran
Published: February 2012

High frequency properties of (a) as-synthesized and (b) flattened by ball milling Fe-based alloys particles and their potential as antenna materials is reported. The high frequency properties of Fe-Co nanoparticles exhibited a resonance peak in the range of a few gigahertz (GHz), and the resonance peak shifted to a higher region for decreasing particle size. However, magnetic permeability was not high enough to be used as high performing electromagnetic wave absorbers. On the other hand, the permeability of Fe-Ni particles at 1 GHz was 2.5 and the magnetic loss was 0.36. However, permeability was enhanced to a value of more than 3 and the magnetic loss decreased by more than half, when the dispersibility and planular aggregates were realized through ball milling. Additional experiments suggested that the particle aggregation had greater influence in the high frequency properties than the composition and magnetic properties. Similarly, when Fe50Co50 particles were also subjected to ball milling, their magnetic loss decreased below the values achieved by Fe-Ni and suggested the possibility of becoming a potential candidate for antenna applications.
High ferromagnetic resonance and thermal stability spinel Ni0.7Mn0.3−xCoxFe2O4 ferrite for ultra high frequency devices
Authors: Lee Jaejin , Hong Yang-Ki , Lee Woncheol , Abo Gavin S. , Park Jihoon , Syslo Ryan , Seong Won-Mo , Park Sang-Hoon , Ahn Won-Ki
Published: February 2012

Magnetic properties and ferromagnetic resonance (FMR) frequency of Ni0.7Mn0.3−xCoxFe2O4 ferrites (NiMnCo: x = 0.00, 0.04, 0.06, and 0.10) were controllable with the concentration of cobalt (Co). The measured saturation magnetization remains almost constant at 57 emu/g in the studied range of the Co content. However, the coercivity increased to 72 Oe (x = 0.10) from 12 Oe (x = 0.00). Ferromagnetic resonance frequency increased from 129 MHz to the GHz frequency with increasing the Co content from x = 0.00 to x = 0.10, but the real part of permeability decreased to 1.6 from 16.7. This is because FMR frequency increases with the magnetocrystalline anisotropy (Hk) of the Co according to fr = (γ/2π)Hk. The permeability decreased with the Co content by µ = 1 + (4πMs/Hk). Temperature coefficient, in the range of 20–100 °C, was 0.002 for Ni0.7Mn0.3Fe2O4 (x = 0.00) and 0.008 for Ni0.7Mn0.2Co0.1Fe2O4 (x = 0.10). The results suggest that Ni0.7Mn0.3−xCoxFe2O4 ferrites have excellent temperature stability, and also are applicable to very high frequency: 30–300 MHz) and ultra high frequency: 300 MHz–3 GHz) devices.
H– beam transport experiments in a solenoid low energy beam transport
Authors: Gabor C. , Back J. J. , Faircloth D. C. , Izaola Z. , Lawrie S. R. , Letchford A. P.
Published: February 2012

The Front End Test Stand (FETS) is located at Rutherford Appleton Laboratory and aims for a high current, fast chopped 3 MeV H– ion beam suitable for future high power proton accelerators like ISIS upgrade. The main components of the front end are the Penning ion source, a low energy beam transport line, an radio-frequency quadrupole (RFQ) and a medium energy beam transport (MEBT) providing also a chopper section and rebuncher. FETS is in the stage of commissioning its low energy beam transport (LEBT) line consisting of three solenoids. The LEBT has to transport an H– high current beam (up to 60 mA) at 65 keV. This is the injection energy of the beam into the RFQ. The main diagnostics are slit–slit emittance scanners for each transversal plane. For optimizing the matching to the RFQ, experiments have been performed with a variety of solenoid settings to better understand the actual beam transport. Occasionally, source parameters such as extractor slit width and beam energy were varied as well. The paper also discusses simulations based on these measurements.
Study on the soft magnetic properties and high frequency characteristics of Co-M (M = Ti, Zr, and Hf) thin films
Authors: Chang H. W. , Huang Y. H. , Hsieh C. C. , Shih C. W. , Chang W. C. , Xue D. S.
Published: February 2012

Soft magnetic properties and high frequency characteristics of Co100-xMx (M = Ti, Zr, and Hf) thin films have been investigated. All M-doped Co100-xMx films exhibit strong induced in-plane uniaxial magnetic anisotropy. With the increase of the x, the 4πMs and coercivity along the hard and easy axes (Hch and Hce) are decreased, while Hk reaches the maximum value for the films having the composition to become the fully amorphous. Among them, less Hf or Zr content, i.e., x = 7, are sufficient in forming the Co100-xMx amorphous, in contrast, more Ti content, i.e., x = 15, should be needed. The optimal properties of 4πMs = 11.0 kG, Hce = 5.4 Oe, Hch = 4.0 Oe, Hk = 320 Oe and fFMR = 5.2 GHz for Co93Hf7 films and 4πMs = 11.7 kG, Hce = 6.1 Oe, Hch = 1.6 Oe, Hk = 266 Oe and fFMR = 4.9 GHz for Co93Zr7 films can be obtained.
The effect of distributed exchange parameters on magnetocaloric refrigeration capacity in amorphous and nanocomposite materials
Authors: Jones N. J. , Ucar H. , Ipus J. J. , McHenry M. E. , Laughlin D. E.
Published: February 2012

The temperature dependent magnetization of nanocomposite alloys has been fit with a modified Handrich-Kobe equation with an asymmetric exchange fluctuation parameter combined with the Arrott-Noakes equation. The two equations of state are combined to calculate the entropy change in the magnetocaloric effect associated with the ferromagnetic to paramagnetic phase transformation. The complete fit for the M(T) of (Fe70Ni30)88Zr7B4Cu nanocomposite powder is accomplished by combining the two theories. We investigate the broadening of the second-order transition arising from asymmetric exchange parameters and resulting from the fluctuations of interatomic spacing found in an amorphous matrix and the asymmetric dependence of exchange energy on interatomic spacing. The magnetic entropy curve revealed extra broadening with a refrigeration capacity (RC) value of 135 J/kg at 5 T, which is comparable to (Fe76Cr8-xMoxCu1B15) ribbons, which have a RC value of 180 J/kg for the same applied field. Broadening of the magnetic entropy can lead to larger RC values and a wider working temperature range, making nanocomposite alloys promising for magnetocaloric applications.
Neoclassical theory inside transport barriers in tokamaks
Authors: Shaing K. C. , Hsu C. T.
Published: February 2012

Inside the transport barriers in tokamaks, ion energy losses sometimes are smaller than the value predicted by the standard neoclassical theory. This improvement can be understood in terms of the orbit squeezing theory in addition to the sonic poloidal E×B Mach number Up,m that pushes the tips of the trapped particles to the higher energy. In general, Up,m also includes the poloidal component of the parallel mass flow speed. These physics mechanisms are the corner stones for the transition theory of the low confinement mode (L-mode) to the high confinement mode (H-mode) in tokamaks. Here, detailed transport fluxes in the banana regime are presented using the parallel viscous forces calculated earlier. It is found, as expected, that effects of orbit squeezing and the sonic Up,m reduce the ion heat conductivity. The former reduces it by a factor of |S|3/2 and the later by a factor of R(Up,m2)exp(-Up,m2) with R(Up,m2), a rational function. Here, S is the orbit squeezing factor.
Laser duration and intensity limits in plasma backward Raman amplifiers
Authors: Malkin V. M. , Toroker Z. , Fisch N. J.
Published: February 2012

The shortest duration and the largest non-focused intensity of laser pulses produced by means of backward Raman amplification (BRA) in plasmas are calculated. These limits occur in moderately undercritical plasmas and are imposed by combined effects of moderately small group velocity dispersion and relativistic electron nonlinearity of the amplified pulses. The efficient BRA range covered by this theory is broader than one known previously. This can be useful for BRA of x-ray pulses in regular or compressed solids and ultra-powerful optical pulses in the lowest density solids.
Estimation of the nitrogen ionization reaction rate using electric arc shock tube data and Bayesian model analysis
Authors: Miki K. , Panesi M. , Prudencio E. E. , Prudhomme S.
Published: February 2012

In this paper, we apply a Bayesian analysis to calibrate the parameters of a model for atomic nitrogen ionization using experimental data from the electric arc shock tube (EAST) wind-tunnel at NASA. We use a one-dimensional plasma flow solver coupled with a radiation solver for the simulation of the radiative signature emitted in the shock-heated air plasma as well as a Park’s two-temperature model for the thermal and chemical non-equilibrium effects. We simultaneously quantify model parameter uncertainties and physical model inadequacies when solving the statistical inverse problem. Prior to the solution of such a problem, we perform a sensitivity analysis of the radiative heat flux in order to identify important sources of uncertainty. This analysis clearly shows the importance of the direct ionization of atomic nitrogen as it mostly influences the radiative heating. We then solve the statistical inverse problem and compare the calibrated reaction rates against values available in the literature. Our calculations estimate the reaction rate of the atomic nitrogen ionization to be (3.7 ± 1.5) × 1011 cm3 mol−1 s−1 at 10 000 K, a range consistent with Park’s estimation. Finally, in order to assess the validity of the estimated parameters, we propagate their uncertainties through a statistical forward problem defined on a prediction scenario different from the calibration scenarios and compare the model predictions against other experimental data.
Identification of electrically active defects in thin dielectric films by spectroscopic ellipsometry
Authors: Price J. , Bersuker G. , Lysaght P. S.
Published: February 2012

A study of resonant photo-absorption features in high-k dielectric film stacks using vacuum ultraviolet spectroscopic ellipsometry demonstrates that all optically observable dielectric-related defects are located in the interfacial SiO2 layer rather than in the bulk high-k film. The defects, located at 2.9 eV, 3.6 eV, 3.9 eV, and 4.75 eV within the bandgap of this bottom interface, are found to be strongly affected by processing conditions. These results are supported by both electrical and physical characterization measurements that identify a consistent trend in the evolution of charge trapping defects for samples subjected to identical processing conditions. In addition, evidence is provided correlating the optically active 2.9 eV defect to positively charged oxygen vacancies in the bottom interfacial layer that have recently been proposed as contributing to the flatband voltage roll-off phenomenon. The close connection between these results and both ab initio calculations and experimental findings substantiate the use of spectroscopic ellipsometry as a unique characterization method for identifying process-induced defects during development and fabrication of dielectric film stacks.