bluuebunny/crossref_metadata_2025 huggingface dataset:
Immunolocalization of c‐Fos and c‐Jun in human oral mucosa and in oral squamous cell carcinoma
Authors: De Sousa Suzana Orsini Machado , Mesquita Ricardo Alves , Pinto Décio Santos , Gutkind Silvio
Published: October 2010

Background:  Studies have addressed the relevance of c‐Jun and c‐Fos proteins in cancer development. In the present study, the expression of c‐Jun and c‐Fos, the major components of transcription factor activator protein (AP1), were evaluated to determine possible alterations to these factors in oral squamous cell carcinoma (OSCC).

Methods:  Fifteen cases of normal oral mucosa and 20 cases of OSCC were retrieved from the Archives of the Surgical Pathology Service at the University of São Paulo. The samples of normal oral mucosa or OSCC originated from different oral mucosal sites. Tissues were submitted for immunohistochemical analysis to detect c‐Jun and c‐Fos proteins. The OSCC was classified as well, intermediate or poorly differentiated.

Results:  The results showed that both c‐Jun and c‐Fos are expressed in normal oral mucosa and in OSCC. In normal mucosa, immunoreactivity for c‐Jun was detected in the cytoplasm of the upper basal layers, while in OSCC, c‐Jun was detected in the nuclei of the cells. C‐Fos expression was observed in the nuclei of cells, both in normal mucosa and in OSCC, but its expression varied according to the cell layer in normal mucosa, and the differentiation of OSCC.

Conclusions:  The nuclear expression of c‐Jun in OSCC, in contrast to its cytoplasmic expression in normal oral mucosa, indicates that c‐Jun may have a role in the development of oral cancer. In contrast, the absence of both c‐Jun and c‐Fos in poorly differentiated carcinoma might be useful in understanding the cell cycle events important in uncontrolled cell growth.
Prognostic role of p21WAF1 expression in areca quid chewing and smoking‐associated oral squamous cell carcinoma in Taiwan
Authors: Yen‐Ping Kuo Mark , Huang Jehn‐Shyun , Kok Sang‐Heng , Kuo Ying‐Shiung , Chiang Chun‐Pin
Published: October 2010

Background:  Alterations in p21WAF1 protein expression have been observed in a wide variety of human cancers by immunohistochemistry, and both decreased and increased levels of p21WAF1 protein expression have been shown to correlate with poor prognosis.

Method:  To examine the relation between p21WAF1 protein expression and prognosis in oral squamous cell carcinomas (SCCs), we performed an immunohistochemical study with antip21WAF1 antibody on 43 oral SCCs. Immunostaining results were then correlated with p53 protein levels, clinicopathological parameters of the tumors and overall patient survival.

Results:  Of the 43 patients, 31 (72%) had tumors with positive p21WAF1 nuclear staining and 27 (63%) had tumors with p53 nuclear staining. There was no significant correlation between p21WAF1 and p53 protein expressions and both mutant p53‐containing oral SCCs overexpressed p21WAF1 protein. In addition, no significant correlation was found between the p21WAF1 expression and the patients' age, sex, oral habit, cancer location, or primary tumor TNM status at the time of initial presentation. The Kaplan‐Meier analysis showed a significant correlation between p21WAF1 protein overexpression and poor patient overall survival (P = 0.049). When p53 and p21WAF1 were evaluated together, the 5‐year overall survival was lowest in p53(+)‐p21WAF1(+) patients and highest in p53(–)‐p21WAF1(–) patients (P = 0.057).

Conclusion:  Combined evaluation of p21WAF1 and p53 expressions may be useful in estimating the prognosis of patients with oral SCCs in Taiwan.
Immunohistochemical study of interleukin‐1β and interleukin‐1 receptor antagonist in an antigen‐induced arthritis of the rabbit temporomandibular joint
Authors: Habu Manabu , Tominaga Kazuhiro , Sukedai Miho , Alstergren Per , Ohkawara Susumu , Kopp Sigvard , Fukuda Jinichi
Published: October 2010

Background:  In temporomandibular joint (TMJ) arthritis, there is limited knowledge of the relationship between interleukin‐1β (IL‐1β) and interleukin‐1 receptor antagonist (IL‐1ra), as well as the source of these cytokines. We investigated the development of an antigen‐induced arthritis in the rabbit TMJ immunohistochemically.

Methods:  Unilateral TMJ arthritis was induced in 32 adult New Zealand White rabbits. From 6 h to 12 weeks after induction of arthritis, topology of IL‐1β and IL‐1ra were observed.

Result:  The acute stage of induced arthritis lasted for one week after induction, thereafter it became chronic. In the early phase of the acute stage, infiltrating inflammatory cells, as well as synovial cells, produced IL‐1β and IL‐1ra. In the late phase of the acute stage, the main source of these cytokines was subsynovial fibroblasts. In this phase of arthritis, IL‐1β and IL‐1ra did not appear to be produced by synovial cells. From the early to intermediate phase of the chronic stage, proliferating synovial cells produced IL‐1β and IL‐1ra. In this phase of the arthritis, these cytokines were also observed in a cluster formation in chondrocytes.

Conclusion:  This arthritis model shows a staging of the joint inflammation process with time. IL‐1β and IL‐1ra are produced by a certain kind of cells depending on the stage of inflammation.
Intra‐epithelial CD8+ T cells and basement membrane disruption in oral lichen planus
Authors: Zhou Xijing J. , Sugerman Philip B. , Savage Neil W. , Walsh Laurence J. , Seymour Gregory J.
Published: October 2010

Background:  We investigated basement membrane (BM) disruption and the distribution of mast cells (MCs) and T cell subsets, in oral lichen planus (OLP) and normal buccal mucosa (NBM) using immunohistochemistry. In OLP, there were increased numbers of tryptase+ MCs in areas of BM disruption (P < 0.05).

Method:  We identified clusters of intraepithelial CD8+ T cells in OLP, specifically in regions of BM disruption. The number of intraepithelial CD8+ T cells in regions of BM disruption was significantly greater than in regions of BM continuity (P < 0.05).

Results:  There were comparable numbers of lamina propria CD8+ T cells in regions of BM disruption and BM continuity. The number of CD4+ T cells in the epithelium and lamina propria of OLP lesions did not vary between regions of BM disruption and BM continuity.

Conclusion:  These data suggest a role for MCs in epithelial BM disruption in OLP. CD8+ T cells may migrate through BM breaks to enter the OLP epithelium.
Compliance with and tolerance of mefloquine and chloroquine + proguanil malaria chemoprophylaxis in French short‐term travellers to sub‐Saharan Africa
Authors: Carme Bernard , Peguet Chantal , Nevez Gilles
Published: October 2010

To compare the compliance with and tolerance of mefloquine (MQ) and chloroquine + proguanil (CQ‐PRO) chemoprophylaxis, we conducted a study using a self‐reported questionnaire in 2 groups of native French adult visitors to Senegal or Kenya. CQ (100 mg daily) + PRO (200 mg daily) prophylaxis was prescribed for all patients tiavelling to Senegal and for those going to Kenya when MQ was contraindicated; MQ (250 mg weekly) was prescribed for the other subjects. There were no significant differences in age, sex, exposition and measures of protection against mosquito bites, concomitant drug use or mean duration of chemoprophylaxis between the 2 groups, and compliance during travel was excellent in both. Chemoprophylaxis was more frequently interrupted prematurely in the MQ group. The rates of overall side‐effects attributed to malaria chemoprophylaxis were 16% for MQ against 12% for CQ‐PRO (not significant). However, nonserirous neuropsychiatric adverse events are more frequent with MQ: 11.5% compared to 2% with CQ‐PRO. MQ should be used with caution.
The need for research on dementia in developing countries
Authors: Prince Martin
Published: October 2010

Dementia is one of the commonest and most disabling late‐life mental disorders. Its prevalence and incidence have been assessed in developed countries, and show little geographical variation between countries and regions. Although most older people live in developing countries, little research has been carried out in those settings. There is some evidence that age‐specific prevalence rates for dementia in developing countries may be relatively low. More research is needed to allow developing countries to estimate the current extent, type and cost of medical and social service provision, and to make confident predictions of future need. Research in different cultures with different levels of economic and industrial development will also increase the variance of environmental exposure, facilitating the identification of environmental risk factors and gene—environment interactions for dementia. Research methodologies need to be adapted to the different circumstances of developing countries, with implications for sampling, cognitive screening and definitive dementia diagnosis.
Leopard or chameleon? The changing character of international health economics
Authors: Mills Anne
Published: October 2010

Over the last 25 years the discipline of health economics has developed substantially. As an applied discipline, it has adapted and changed over time in response to the changing concerns of policy‐makers, planners and managers. This paper questions whether it is like a chameleon, changing its appearance in response to the external environment, or like the leopard that never changes its spots. In answering the question, the paper presents an overview of the development of health economics as it has been applied in low and middle income countries distinguishing three eras, the 1970s, 1980s, and 1990s, and argues that in each of these eras the preoccupations of health economists have been somewhat different. In each era the key contributions of health economics are identified. The paper ends by considering future research priorities, and the obligations of developed country institutions in terms of research topics and mode of work.
A comparison of use of a pyrethroid either for house spraying or for bednet treatment against malaria vectors
Authors: Curtis C. F. , Maxwell C. A. , Maxwell C. A. , Finch R. J. , Finch R. J. , Njunwa K. J.
Published: October 2010

In an intensely malarious area in north‐east Tanzania, microencapsulated lambdacyhalothrin was used in four villages for treatment of bednets (provided free of charge) and in another four villages the same insecticide was used for house spraying. Another four villages received neither intervention until the end of the trial but were monitored as controls. Bioassays showed prolonged persistence of the insecticidal residues. Light traps and ELISA testing showed reduction of the malaria vector populations and the sporozoite rates, leading to a reduction of about 90% in the entomological inoculation rate as a result of each treatment. Collections of blood fed mosquitoes showed no diversion from biting humans to biting animals. Incidence of re‐infection was measured by weekly monitoring of cohorts of 60 children per village, after clearing pre‐existing infection with chlorproguanil‐dapsone. The vector control was associated with a reduction in probability of re‐infection per child per week by 54–62%, with no significant difference between the two vector control methods. Cross‐sectional surveys for fever, parasitaemia, haemoglobin and weight showed association of high parasitaemia with fever and anaemia and beneficial effects of each intervention in reducing anaemia. However, passive surveillance by resident health assistants showed no evidence for reduced prevalence of fever or parasitaemia. Net treatment consumed only about one sixth as much insecticide as house spraying and it was concluded that the former intervention would work out cheaper and nets were actively demanded by the villagers, whereas spraying was only passively assented to.
Nutritional status of children admitted to hospital with different diseases and its relationship to outcome in The Gambia, West Africa
Authors: Man W. D‐C. , Man W. D‐C. , Weber M. , Weber M. , Palmer A. , Palmer A. , Schneider G. , Wadda R. , Jaffar S. , Jaffar S. , Mulholland E. K. , Greenwood B. M. , Greenwood B. M.
Published: October 2010

Admission records from two paediatric units in The Gambia were used to explore the relationship between admission weight and different diseases. In total 13579 hospitalized children were analysed. For comparison, 7399 children were recruited from several surveys of well subjects to provide anthropometric values for healthy Gambian children. Compared to the control children, mean admission weights were lower for malaria (weight for age z‐score: − 1.602), cerebral malaria (− 1.547), transfused malarial anaemia (− 1.764), pneumonia (− 1.725), meningitis (− 1.362), gastro‐enteritis (− 2.497) and malnutrition (− 3.786). Children with bronchiolitis did not have a significantly different weight for age than the controls. Outcome of the hospital admission was recorded and related to the weight on admission. In all disease categories the death rate rose with decreasing admission weight with the exception of bronchiolitis. For all diseases taken together, case fatality was 7.2% for children with a weight for age z‐score above – 2 Standard Deviations (SD), 9.3% between − 2 and − 3 SD, 15.6% between − 3 and − 4 SD and 22.7% for children with weight for age SD z‐scores less than – 4. Malnourished children are more susceptible to several infectious diseases frequently seen in developing countries and nutritional interventions, as well as standard treatment, may improve outcome.
Megazol combined with suramin: a chemotherapy regimen which reversed the CNS pathology in a model of human African trypanosomiasis in mice
Authors: Enanga B. , Keita M. , Chauvière G. , Dumas M. , Bouteille B.
Published: October 2010

Chemotherapy for human African trypanosomiasis (HAT), or sleeping sickness, is unreliable because of resistance, refraction and toxic and adverse side‐effects. Using a long‐term experimental model of HAT with involvement of the central nervous system (CNS), we tested the ability of a megazol and suramin combination treatment to eliminate CNS trypanosomes. This consisted of 20 mg suramin per kg body weight administered intraperitoneally (IP), followed 24 h later by 4 daily doses (80 mg/kg) of megazol given either IP or per os. One week post‐treatment, neurological disorders had disappeared. One of 15 mice relapsed in each application group at 81 and 98 days after treatment, respectively. At six months, no signs of relapse were seen in remaining mice, indicating that this chemotherapy regimen was curative. Immunohistochemical (astrocytosis) and histological (inflammatory lesions) examinations of brain tissues showed that animals returned to normal from 2 months post‐treatment. These results suggest that the megazol‐suramin combination reversed the CNS pathology in this model.
Meningitis caused by a serogroup W135 clone of the ET‐37 complex of Neisseria meningitidis in West Africa
Authors: Kwara A. , Adegbola R. A. , Corrah P. T. , Weber M. , Achtman M. , Morelli G. , Caugant D. A. , Greenwood B. M.
Published: October 2010

Summary Meningococci belonging to serogroup W135 caused several cases of meningococcal meningitis in The Gambia in 1995 and were isolated during a serogroup A epidemic in Mali in 1994. The eight isolates tested belonged to the same clone of the ET‐37 complex and differed in several bands from the pulsed‐field gel electrophoresis restriction pattern of serogroup C meningococci of the ET‐37 complex isolated in Mali. Three of 6 patients infected in The Gambia died, indicating that this W135 clone is virulent. Vaccines that protect only against infections with meningococci belonging to serogroups A and C are usually used to control outbreaks in Africa, although vaccines containing the W135 polysaccharide are available. The findings of this study indicate that outbreaks of meningococcal meningitis in Africa can be associated with serogroup W135 infections and that serogrouping is essential before vaccination campaigns are started.
Commissioning of electron cyclotron emission imaging instrument on the DIII-D tokamak and first data
Authors: Tobias B. , Domier C. W. , Liang T. , Kong X. , Yu L. , Yun G. S. , Park H. K. , Classen I. G. J , Boom J. E. , Donné A. J. H. , Munsat T. , Nazikian R. , Van Zeeland M. , Boivin R. L. , Luhmann N. C.
Published: October 2010

A new electron cyclotron emission imaging diagnostic has been commissioned on the DIII-D tokamak. Dual detector arrays provide simultaneous two-dimensional images of Te fluctuations over radially distinct and reconfigurable regions, each with both vertical and radial zoom capability. A total of 320 (20 vertical×16 radial) channels are available. First data from this diagnostic demonstrate the acquisition of coherent electron temperature fluctuations as low as 0.1% with excellent clarity and spatial resolution. Details of the diagnostic features and capabilities are presented.
Using gamma-ray emission to measure areal density of inertial confinement fusion capsules
Authors: Hoffman N. M. , Wilson D. C. , Herrmann H. W. , Young C. S.
Published: October 2010

Fusion neutrons streaming from a burning inertial confinement fusion capsule generate gamma rays via inelastic nuclear scattering in the ablator of the capsule. The intensity of gamma-ray emission is proportional to the product of the ablator areal density (ρR) and the yield of fusion neutrons, so by detecting the gamma rays we can infer the ablator areal density, provided we also have a measurement of the capsule’s total neutron yield. In plastic-shell capsules, for example, C12 nuclei emit gamma rays at 4.44 MeV after excitation by 14.1 MeV neutrons from D+T fusion. These gamma rays can be measured by a new gamma-ray detector under development. Analysis of predicted signals is in progress, with results to date indicating that the method promises to be useful for diagnosing imploded capsules.
Relatively scaled ECE temperature profiles of KSTAR plasmas
Authors: Choi M. J. , Yun G. S. , Park H. K. , Jeon Y. M. , Jeong S. H.
Published: October 2010

A scheme to obtain relatively scaled profiles of electron cyclotron emission (ECE) temperature directly from uncalibrated raw radiometer data is proposed and has been tested for the 2009 campaign KSTAR plasmas. The proposed method utilizes a position controlled system to move the plasma adiabatically and compares ECE radiometer channels at the same relative radial positions assuming the profile consistency during the adiabatic change. This scaling method is an alternative solution when an absolute calibration is unreliable or too time consuming. The application to the two dimensional ECE imaging data, wherein calibration is extremely difficult, may also prove to be useful.
Data acquisition and processing system of the electron cyclotron emission imaging system of the KSTAR tokamak
Authors: Kim J. B. , Lee W. , Yun G. S. , Park H. K. , Domier C. W. , Luhmann N. C.
Published: October 2010

A new innovative electron cyclotron emission imaging (ECEI) diagnostic system for the Korean Superconducting Tokamak Advanced Research (KSTAR) produces a large amount of data. The design of the data acquisition and processing system of the ECEI diagnostic system should consider covering the large data production and flow. The system design is based on the layered structure scalable to the future extension to accommodate increasing data demands. Software architecture that allows a web-based monitoring of the operation status, remote experiment, and data analysis is discussed. The operating software will help machine operators and users validate the acquired data promptly, prepare next discharge, and enhance the experiment performance and data analysis in a distributed environment.
Development of two color laser diagnostics for the ITER poloidal polarimeter
Authors: Kawahata K. , Akiyama T. , Tanaka K. , Nakayama K. , Okajima S.
Published: October 2010

Two color laser diagnostics using terahertz laser sources are under development for a high performance operation of the Large Helical Device and for future fusion devices such as ITER. So far, we have achieved high power laser oscillation lines simultaneously oscillating at 57.2 and 47.7 μm by using a twin optically pumped CH3OD laser, and confirmed the original function, compensation of mechanical vibration, of the two color laser interferometer. In this article, application of the two color laser diagnostics to the ITER poloidal polarimeter and recent hardware developments will be described.
Nanostructure determines the intensity-dependence of open-circuit voltage in plastic solar cells
Authors: Reid Obadiah G. , Xin Hao , Jenekhe Samson A. , Ginger David S.
Published: October 2010

We use photoconductive atomic force microscopy to make local measurements of the open-circuit voltage (VOC) as a function of light intensity in several polymer/fullerene bulk heterojunction blend solar cells. We find significant local variations in the slope of the open-circuit voltage plotted versus the log of the light intensity. By studying a model alkoxy-poly(p)-pheneylene-vinylene/phenyl-C61-butyric acid methyl ester system with known vertical structure, and by comparing our results with a simple numerical model, we associate these local differences in VOC versus light intensity with lateral variations in vertical morphology/composition. These results not only provide a qualitative method of mapping lateral variations in vertical structure/composition by making local measurements of VOC as a function of light intensity but suggest that the unusual light-intensity dependence of VOC (diode ideality factors in the light) of many organic photovoltaics can be linked with morphological heterogeneity.
Design criteria of the bolometer diagnostic for steady-state operation of the W7-X stellarator
Authors: Zhang D. , Burhenn R. , Koenig R. , Giannone L. , Grodzki P. A. , Klein B. , Grosser K. , Baldzuhn J. , Ewert K. , Erckmann V. , Hirsch M. , Laqua H. P. , Oosterbeek J. W.
Published: October 2010

A bolometric diagnostic system with features necessary for steady-state operation in the superconducting stellarator W7-X was designed. During a pulse length of 1800 s with an ECRH (electron cyclotron resonance heating) power of 10 MW, the components suffer not only from a large thermal load but also from stray radiation of the nonabsorbed isotropic microwaves. This paper gives an overview of the technical problems encountered during the design work and the solutions to individual problems to meet the special requirements in W7-X, e.g., component thermal protection, detector offset thermal drift suppression, as well as a microwave shielding technique.
Development of KSTAR ECE imaging system for measurement of temperature fluctuations and edge density fluctuations
Authors: Yun G. S. , Lee W. , Choi M. J. , Kim J. B. , Park H. K. , Domier C. W. , Tobias B. , Liang T. , Kong X. , Luhmann N. C. , Donné A. J. H.
Published: October 2010

The ECE imaging (ECEI) diagnostic tested on the TEXTOR tokamak revealed the sawtooth reconnection physics in unprecedented detail, including the first observation of high-field-side crash and collective heat transport [H. K. Park, N. C. Luhmann, Jr., A. J. H. Donné et al., Phys. Rev. Lett. 96, 195003 (2006)]. An improved ECEI system capable of visualizing both high- and low-field sides simultaneously with considerably better spatial coverage has been developed for the KSTAR tokamak in order to capture the full picture of core MHD dynamics. Direct 2D imaging of other MHD phenomena such as tearing modes, edge localized modes, and even Alfvén eigenmodes is expected to be feasible. Use of ECE images of the optically thin edge region to recover 2D electron density changes during L/H mode transitions is also envisioned, providing powerful information about the underlying physics. The influence of density fluctuations on optically thin ECE is discussed.
Diagnostics design for steady-state operation of the Wendelstein 7-X stellarator
Authors: König R. , Baldzuhn J. , Biel W. , Biedermann C. , Burhenn R. , Bozhenkov S. , Cantarini J. , Dreier H. , Endler M. , Hartfuss H.-J. , Hildebrandt D. , Hirsch M. , Jakubowski M. , Jimenez-Gomez R. , Kocsis G. , Kornejev P. , Krychowiak M. , Laqua H. P. , Laux M. , Oosterbeek J. W. , Pasch E. , Richert T. , Schneider W. , Schweer B. , Svensson J. , Thomsen H. , Weller A. , Werner A. , Wolf R. , Zhang D. , Zoletnik S.
Published: October 2010

The status of the diagnostic developments for the quasistationary operable stellarator Wendelstein 7-X (maximum pulse length of 30 min at 10 MW ECRH heating at 140 GHz) will be reported on. Significant emphasis is being given to the issue of ECRH stray radiation shielding of in-vessel diagnostic components, which will be critical at high density operation requiring O2 and OXB heating.
2D electron cyclotron emission imaging at ASDEX Upgrade (invited)
Authors: Classen I. G. J. , Boom J. E. , Suttrop W. , Schmid E. , Tobias B. , Domier C. W. , Luhmann N. C. , Donné A. J. H. , Jaspers R. J. E. , de Vries P. C. , Park H. K. , Munsat T. , García-Muñoz M. , Schneider P. A.
Published: October 2010

The newly installed electron cyclotron emission imaging diagnostic on ASDEX Upgrade provides measurements of the 2D electron temperature dynamics with high spatial and temporal resolution. An overview of the technical and experimental properties of the system is presented. These properties are illustrated by the measurements of the edge localized mode and the reversed shear Alfvén eigenmode, showing both the advantage of having a two-dimensional (2D) measurement, as well as some of the limitations of electron cyclotron emission measurements. Furthermore, the application of singular value decomposition as a powerful tool for analyzing and filtering 2D data is presented.
Lattice relaxation in the highly-contrasted Zn1−xBexSe alloy: An extended x-ray absorption fine structure study
Authors: Ganguli Tapas , Mazher J. , Polian A. , Deb S. K. , Villain F. , Pages O. , Paszkowicz W. , Firszt F.
Published: October 2010

We have performed extended x-ray absorption fine structure (EXAFS) measurements at the Zn and Se K edges of (Zn,Be)Se alloy. This alloy exhibits an unusually large contrast in the physical properties (bond stiffness and bond lengths) of its constituting bonds, leading to a uniquely well-resolved 1-bond→2-mode behavior in the already reported Raman spectra of this material system. The nearest and next nearest neighbor distances of Zn and Se atoms, the pseudo Debye–Waller factors (σ2) for these distances, as well as various bond angles, are determined as a function of the alloy composition after fitting the EXAFS equations. The lattice relaxation is discussed in terms of the distorted tetrahedral structure of the ternaries. We conclude that the accommodation of the local strain due to the difference in Zn–Se and Be–Se bond lengths is predominantly achieved by a displacement of the Se sublattice toward Be, the (Be,Zn)-mixed cation sublattice remaining quasirigid. Besides, we find that the 1-bond→2-mode behavior in the bond force constants (Raman data) is not paralleled by an obvious 1-bond→2-mode behavior in the bond lengths (EXAFS data). However, the dependence of σ2 for the nearest neighbor bond length as a function of the alloy composition is basically consistent with such a behavior. The difference in Be–Se bond lengths as predicted by earlier ab initio calculations, of 0.04 Å, is probably too small to be resolved by our present EXAFS measurements. Further, by combining the analysis of EXAFS data with available Raman data, we were able to provide a preliminary estimate of the BeSe TO mode Grüneisen parameter.
Pulse delay in wave propagation with composed pupils
Authors: Ranfagni A. , Mugnai D.
Published: October 2010

A composed pupil system was tested—in the microwave range—in order to verify the possibility of obtaining a considerable reduction in the beam width and a field concentration along the axial axis, as compared to normal pupils. Here we present further experimental investigation, always in the microwave range, in order to evaluate the pulse delay in the propagation. An interpretation of the results is given along the lines of a stochastic model already formulated for wave propagation in the presence of dissipation.
Laser beam combiner for Thomson scattering core LIDAR
Authors: Balboa I. , Huang B. , Naylor G. , Walsh M. , Sirinelli A. , Parsons P. , Fessey J. , Townsend M. , Beurskens M. , Conway N. , Flanagan J. , Kempenaars M. , Kirk A.
Published: October 2010

The light detection and ranging Thomson scattering (TS) diagnostic is advantageous since it only requires a single view port into the tokamak. This technique requires a short pulse laser at high energy, usually showing a limited repetition rate. Having multiple lasers will increase the repetition rate. This paper presents a scanning mirror as a laser beam combiner. Measurements of the position accuracy and jitter show that the pointing stability of the laser beam is within ±25 μrad for over tens of seconds. A control feedback loop is implemented to demonstrate the long term stability. Such a system could be applied for ITER and JET.
High temperature emissivity, reflectivity, and x-ray absorption of BiFeO3
Authors: Massa Néstor E. , del Campo Leire , de Souza Meneses Domingos , Echegut Patrick , Fabbris Gilberto F. L. , Azevedo G. de M. , Martínez-Lope María Jesús , Alonso José Antonio
Published: October 2010

We report on the lattice evolution of BiFeO3 as function of temperature using far infrared emissivity, reflectivity, and x-ray absorption local structure. A power law fit to the lowest frequency soft phonon in the magnetic ordered phase yields an exponent β=0.25 as for a tricritical point. At about 200 K below TN∼640 K it ceases softening as consequence of BiFeO3 metastability. We identified this temperature as corresponding to a crossover transition to an order-disorder regime. Above ∼700 K strong band overlapping, merging, and smearing of modes are consequence of thermal fluctuations and chemical disorder. Vibrational modes show band splits in the ferroelectric phase as emerging from triple degenerated species as from a paraelectric cubic phase above TC∼1090 K. Temperature dependent x-ray absorption near edge structure (XANES) at the Fe K edge shows that lower temperature Fe3+ turns into Fe2+. While this matches the FeO wüstite XANES profile, the Bi LIII-edge downshift suggests a high temperature very complex bond configuration at the distorted A perovskite site. Overall, our local structural measurements reveal high temperature defect-induced irreversible lattice changes, below, and above the ferroelectric transition, in an environment lacking of long-range coherence. We did not find an insulator to metal transition prior to melting.
Intersubband absorption energy shifts in 3-level system for asymmetric quantum well terahertz emitters
Authors: Song Yafeng , Lu Yanwu , Zhang Biao , Xu Xiaoqing , Wang Jun , Guo Yan , Shi Kai , Li Zhiwei , Liu Xianglin , Yang Shaoyan , Zhu Qinsheng , Wang Zhanguo
Published: October 2010

Intersubband absorption energy shifts in 3-level system stemming from depolarization and excitonlike effects are investigated. Analytically, the expressions we derive present good explanations to the conventional 2-level results and bare potential transition energy results; and numerical results show that they are more exact than the previous studies to describe the 3-level system depolarization and excitonlike shift (DES) character especially for higher carrier density (more than 8×1011 cm−2). One interesting detail we find is that the “large blue” DES becomes “slight redshift” in the low doping limit (less than 1.9×1011 cm−2), which may be neglected by the previous studies of intersubband transitions. Temperature character of DES in the step well structure is also numerically studied. Finally the above are applied to calculate asymmetric step quantum well structures. The two main functional aspects of terahertz (THz) emitters are discussed and several basic optimizing conditions are considered. By adjusting the well geometry parameters and material composition systematically, some optimized structures which satisfy all of the six conditions are recommended in tables. These optimizations may provide useful references to the design of 3-level-based optically pumping THz emitters.
Magnetization configurations and reversal of thin magnetic nanotubes with uniaxial anisotropy
Authors: Chen A. P. , Guslienko K. Y. , Gonzalez J.
Published: October 2010

We present calculations of the magnetization configuration and reversal behavior of magnetic nanotubes with uniaxial anisotropy by means of two-dimensional micromagnetic simulations and analytical methods. The tube radii R from 50 to 150 nm and the tube length /radius aspect ratio L/R≤20 were explored. For a finite length of magnetic nanotubes the magnetization configuration is characterized by a uniformly magnetized along the tube axis middle part and two nonuniform curling states of a length Lc in two ends of the tube with the same or opposite magnetization rotating senses, referring as C-state or B-state, respectively. We found that the magnetization configuration of the C-state exists for thin nanotubes with the tube thickness, ΔR, in the range of ΔR/R≤0.2. For thicker nanotubes the strong magnetostatic stray field forces the change of rotating senses of the end domains in opposite directions (the B-state). The transition from the C-state to a vortex state with in-plane magnetization is described as function of the tube geometrical parameters. The nanotube hysteresis loops and switching fields were calculated. The simple analytical model was developed to describe the nanotube magnetization reversal reducing its description to the Stoner–Wohlfarth model with effective parameters. The equilibrium state of nanotube is described in terms of θ, the angle of the magnetization deviation from the intrinsic tube easy axis. The L/R dependence of the C-state magnetization, the shape of hysteresis loops and the switching field values are described by a dependence of θ on L/R.
Band gap dependent thermophotovoltaic device performance using the InGaAs and InGaAsP material system
Authors: Tuley R. S. , Nicholas R. J.
Published: October 2010

Thermophotovoltaic cells with a range of band gaps are modeled under a variety of illumination conditions, including a range of source temperatures and a variable degree of spectral control. Thus, the balance between the requirements of high power densities and high efficiencies can be investigated. The influence of elevated cell temperatures, cell cooling, Auger recombination, and series resistances have been included, and all weight the optimum band gap thermophotovoltaic cell toward higher band gaps than the ∼0.5–0.6 eV conventional optimum. The cells have been modeled using fundamental physical parameters from the InGaAs and InGaAsP material system which accurately reproduce reported device performance and allow a comparison to theoretical limits.
Structures and energetics of helium cluster cations: Equilibrium geometries revisited through the genetic algorithm approach
Authors: Oleksy Karel , Karlický František , Kalus René
Published: October 2010

Equilibrium geometries and dissociation energies of HeN+ clusters have been calculated for N=3–35 using an extended genetic algorithm approach and a semiempirical model of intracluster interactions [P. J. Knowles, J. N. Murrell, and E. J. Hodge, Mol. Phys. 85, 243 (1995)]. A general aufbau principle is formulated for both ionic cores and neutral solvation shells, and the results are thoroughly compared with other theoretical data available for helium cluster cations in literature.
Doppler spectroscopy and D-alpha emission diagnostics for the C-2 FRC plasma
Authors: Gupta Deepak K. , Paganini E. , Balvis A. , Bonelli L. , Deng B. H. , Giammanco F. , Gornostaeva O. , Hayashi R. , Knapp K. , Marsili P. , McKenzie M. , Pousa-Hijos R. , Primavera S. , Schroeder J. , Tuszewski M.
Published: October 2010

Two Doppler spectroscopy diagnostics with complementary capabilities are developed to measure the ion temperatures and velocities of FRC plasmas in the C-2 device. First, the multichord ion doppler diagnostic can simultaneously measure 15 chords of the plasma using an image intensified camera. Second, a single-chord fast-response ion Doppler diagnostic provides much higher faster time response by using a 16-channel photo-multiplier tube array. To study the neutral density of deuterium under different wall and plasma conditions, a highly sensitive eight-channel D-alpha diagnostic has been developed and calibrated for absolute radiance measurements. These spectroscopic diagnostics capabilities, combined with other plasma diagnostics, are helping to understand and improve the field reversed configuration plasmas in the C-2 device.
Objectives and layout of a high-resolution x-ray imaging crystal spectrometer for the large helical device
Authors: Bitter M. , Hill K. , Gates D. , Monticello D. , Neilson H. , Reiman A. , Roquemore A. L. , Morita S. , Goto M. , Yamada H. , Rice J. E.
Published: October 2010

A high-resolution x-ray imaging crystal spectrometer, whose concept was tested on NSTX and Alcator C-Mod, is being designed for the large helical device (LHD). This instrument will record spatially resolved spectra of helium-like Ar16+ and will provide ion temperature profiles with spatial and temporal resolutions of <2 cm and ≥10 ms, respectively. The spectrometer layout and instrumental features are largely determined by the magnetic field structure of LHD. The stellarator equilibrium reconstruction codes, STELLOPT and PIES, will be used for the tomographic inversion of the spectral data.
Magnetically insulated baffled probe for real-time monitoring of equilibrium and fluctuating values of space potentials, electron and ion temperatures, and densities
Authors: Demidov V. I. , Koepke M. E. , Raitses Y.
Published: October 2010

By restricting the electron-collection area of a cold Langmuir probe compared to the ion-collection area, the probe floating potential can become equal to the space potential, and thus conveniently monitored, rather than to a value shifted from the space potential by an electron-temperature-dependent offset, i.e., the case with an equal-collection-area probe. This design goal is achieved by combining an ambient magnetic field in the plasma with baffles, or shields, on the probe, resulting in species-selective magnetic insulation of the probe collection area. This permits the elimination of electron current to the probe by further adjustment of magnetic insulation which results in an ion-temperature-dependent offset when the probe is electrically floating. Subtracting the floating potential of two magnetically insulated baffled probes, each with a different degree of magnetic insulation, enables the electron or ion temperature to be measured in real time.
Radio frequency breakdown between structured parallel plate electrodes with a millimetric gap in low pressure gases
Authors: Legradic B. , Howling A. A. , Hollenstein C.
Published: October 2010

This paper presents an investigation into radio frequency (rf) breakdown for electrodes with holes or protrusions, approximating the situation in real reactors and providing a benchmark for fluid simulations. rf breakdown curves (voltage versus pressure) generally show a steep left-hand branch at low pressures and a flatter right-hand branch at higher pressures. Introducing protrusions or holes in parallel plate electrodes will lower the breakdown voltage in certain conditions. Yet experiments show that the breakdown curves are not perceptibly influenced by the increased electric field at sharp edges or ridges. Instead, both experiments and simulation show that breakdown at high pressure will occur at the protrusion providing the smallest gap, while breakdown at low pressure will occur in the aperture providing the largest gap. This holds true as long as the feature in question is wide enough. Features that are too narrow will lose too many electrons due to diffusion, either to the walls of the apertures or to the surroundings of the protrusion, which negates the effect on the breakdown voltage. The simulation developed presents a tool to aid the design of complex rf parts for dark-space shielding.
Strategy for the absolute neutron emission measurement on ITER
Authors: Sasao M. , Bertalot L. , Ishikawa M. , Popovichev S.
Published: October 2010

Accuracy of 10% is demanded to the absolute fusion measurement on ITER. To achieve this accuracy, a functional combination of several types of neutron measurement subsystem, cross calibration among them, and in situ calibration are needed. Neutron transport calculation shows the suitable calibration source is a DT/DD neutron generator of source strength higher than 1010 n/s (neutron/second) for DT and 108 n/s for DD. It will take eight weeks at the minimum with this source to calibrate flux monitors, profile monitors, and the activation system.
Temporal symmetry of individual filaments in different spatial symmetry filaments pattern in a dielectric barrier discharge
Authors: Dong L. F. , Xiao H. , Fan W. L. , Yin Z. Q. , Zhao H. T.
Published: October 2010

The temporal behavior of individual filament in different spatial symmetry filaments patterns in dielectric barrier discharge is investigated by using an optical method. A series of return maps of the discharge moments of individual filaments is given. It is found that the temporal symmetry of individual filament changes with the change of the spatial symmetry of filaments pattern as the applied voltage increases. The role of wall charges for this phenomenon is analyzed.
Calculation of the Johann error for spherically bent x-ray imaging crystal spectrometers
Authors: Wang E. , Beiersdorfer P. , Gu M. , Bitter M. , Delgado-Aparicio L. , Hill K. W. , Reinke M. , Rice J. E. , Podpaly Y.
Published: October 2010

New x-ray imaging crystal spectrometers, currently operating on Alcator C-Mod, NSTX, EAST, and KSTAR, record spectral lines of highly charged ions, such as Ar16+, from multiple sightlines to obtain profiles of ion temperature and of toroidal plasma rotation velocity from Doppler measurements. In the present work, we describe a new data analysis routine, which accounts for the specific geometry of the sightlines of a curved-crystal spectrometer and includes corrections for the Johann error to facilitate the tomographic inversion. Such corrections are important to distinguish velocity induced Doppler shifts from instrumental line shifts caused by the Johann error. The importance of this correction is demonstrated using data from Alcator C-Mod.
Defining the infrared systems for ITER
Authors: Reichle R. , Andrew P. , Counsell G. , Drevon J.-M. , Encheva A. , Janeschitz G. , Johnson D. , Kusama Y. , Levesy B. , Martin A. , Pitcher C. S. , Pitts R. , Thomas D. , Vayakis G. , Walsh M.
Published: October 2010

The International Thermonuclear Experimental Reactor will have wide angle viewing systems and a divertor thermography diagnostic, which shall provide infrared coverage of the divertor and large parts of the first wall surfaces with spatial and temporal resolution adequate for operational purposes and higher resolved details of the divertor and other areas for physics investigations. We propose specifications for each system such that they jointly respond to the requirements. Risk analysis driven priorities for future work concern mirror degradation, interfaces with other diagnostics, radiation damage to refractive optics, reflections, and the development of calibration and measurement methods for varying optical and thermal target properties.
X-ray crystal spectrometer for opacity measurements in the 8–18 Å spectral range at the LULI laser facility
Authors: Reverdin C. , Thais F. , Loisel G. , Bougeard M.
Published: October 2010

An x-ray crystal spectrometer was built in order to measure opacities in the 8–18 Å spectral range with an average spectral resolution of ⟨λ/δλ⟩∼400. It has been successfully used at the LULI-2000 laser facility (See C. Sauteret, rapport LULI 2001, 88 (2002) at École Polytechnique (France) to measure in the same experimental conditions the 2p-3d transitions of several elements with the neighboring atomic number Z: Fe, Ni, Cu, and Ge [G. Loisel et al., High Energy Density Phys. 5, 173 (2009)]. Hence, a spectrometer with a wide spectral range is needed. This spectrometer features two lines of sight. In this example, one line of sight looks through the sample and the other one is looking directly at the backlighter emission. Both are outfitted with a spherical condensing mirror. A TlAP crystal is used for spectral dispersion. Detection is made with an image plate Fuji BAS TR2025, which is sensitive to x rays. We present some experimental results showing the performances of this spectrometer.
Potential measurements with heavy ion beam probe system on LHD
Authors: Shimizu A. , Ido T. , Nakamura S. , Toi K. , Nishiura M. , Kato S.
Published: October 2010

The heavy ion beam probe system in the Large Helical Device (LHD) was improved as follows. At first, the additional new sweeper was installed into the diagnostic port to extend the observable region. By using this sweeper, the potential profile was measured in a wider minor radius range than in previous experiments, in the case of outward shifted magnetic configuration of LHD. Next, the real time control system was installed to control the probe beam orbit for measuring the potential in plasma with large plasma current. In this system, a digital signal processor was used to control the probe beam in real time. The system worked well in the fixed position observation mode. In the sweeping mode for profile measurement, this control system became unstable. The details of this system and the experimental results are reported in this article.
Optimizing the operation of a high resolution vertical Johann spectrometer using a high energy fluorescer x-ray source
Authors: Haugh Michael , Stewart Richard
Published: October 2010

This paper describes the operation and testing for a vertical Johann spectrometer (VJS) operating in the 13 keV range. The spectrometer is designed to use thin curved mica crystals or thick germanium crystals. The VJS must have a resolution of E/ΔE=3000 or better to measure the Doppler broadening of highly ionized krypton and operate at a small x-ray angle in order to be used as a diagnostic in a laser plasma target chamber. The VJS was aligned, tested, and optimized using a fluorescer type high energy x-ray (HEX) source located at National Security Technologies (NSTec), LLC, in Livermore, CA. The HEX uses a 160 kV x-ray tube to excite fluorescence from various targets. Both rubidium and bismuth fluorescers were used for this effort. This presentation describes the NSTec HEX system and the methods used to optimize and characterize the VJS performance.
Conceptual design of the collection optics for the edge Thomson scattering system in ITER
Authors: Yatsuka E. , Hatae T. , Suitoh S. , Aida Y. , Kusama Y.
Published: October 2010

Neutron and gamma-ray irradiation complicates the design of the edge Thomson scattering (TS) system in ITER. The TS light is relayed through the relaying optics with labyrinth and fiber coupling optics. Electron density of 2×1019 m−3 is sufficient to measure Te and ne within a 10% and 5% margin of error, respectively, with a spatial resolution of 5 mm. This system can cover from 0.85 to 1 of the normalized minor radius. The time resolution is 10 ms, which is determined by the repetition rate of the laser device. A super-Gaussian is the ideal laser profile for the laser injection optics to avoid a breakdown of the filling gas used in density calibration through Raman scattering.
Electron energy-loss spectroscopy study of Yb doped ZnO
Authors: Jiang Nan , Ye Song , Qiu Jianrong
Published: October 2010

The diffusion of rare-earth ion, Yb3+, into ZnO lattice has been measured using spatially resolved electron energy-loss spectroscopy in transmission electron microscopy. Although a trace of Yb3+ can be detected in ZnO, the diffusion distance was only in a magnitude of several tens of nanometers. It also discovered that large amounts of interstitial O were formed in the Yb3+ diffusion region. These interstitial O formed a thin layer (∼20 nm) which separated the Yb3+ diffusion layer from the bulk ZnO.