bluuebunny/crossref_metadata_2025 huggingface dataset:
GPR27 expression correlates with prognosis and tumor progression in gliomas
Authors: Cai Changcheng , Hu Libo , Wu Ke , Liu Yinggang
Published: April 2024

Backgrounds

Glioma is a highly aggressive type of brain tumor, and its prognosis is still poor despite recent progress in treatment strategies. G protein-coupled receptor 27 (GPR27) is a member of the G protein-coupled receptor family and has been reported to be involved in various cellular processes, including tumor progression. Nevertheless, the clinical potential and tumor-related role of GPR27 in glioma remain unknown. Here we aimed to explore the function and role of GPR27 in gliomas.

Methods

In the current study, we evaluated the expression and clinical significance of GPR27 in gliomas using data from The Cancer Genome Atlas (TCGA) datasets. We also conducted cellular experiments to evaluate the functional role of GPR27 in glioma cell growth.

Results

We found that GPR27 expression level was closely associated with disease status of glioma. Of note, GPR27 was negatively correlated with WHO grade, with grade IV samples showing the lowest GPR27 levels, while grade II samples showed the highest levels. Patients with IDH mutation or 1p/19q co-deletion exhibited higher GPR27 levels. In addition, lower GPR27 levels were correlated with higher death possibilities. In cellular experiments, we confirmed that GPR27 inhibited glioma cell growth.

Conclusions

Our results indicate that GPR27 may function as a potential prognostic biomarker and therapeutic target in gliomas. Further studies are needed to illustrate the signaling mechanism and clinical implications of GPR27 in gliomas.
Effectiveness of gamification in nursing degree education
Authors: Sanz-Martos Sebastián , Álvarez-García Cristina , Álvarez-Nieto Carmen , López-Medina Isabel M. , López-Franco María Dolores , Fernandez-Martinez Maria E. , Ortega-Donaire Lucía
Published: April 2024

Background

Previous research in nursing has found favorable results from the use of teaching methodologies alternative to lectures. One of the complementary methodologies used for university teaching is gamification, or the inclusion of game elements, creating a dynamic learning environment that allows the acquisition of knowledge and the development of other skills necessary for nursing students. The purpose of this study was to evaluate the effect of a gamification session on student satisfaction and knowledge scores in nursing students in simulated laboratory practice.

Methods

A pre-post quasi-experimental study was conducted with 122 students from the nursing degree program who participated in the research. The evaluation consisted of four sessions of three hours each. In two sessions, participants were trained through a vertical methodology, by means of theoretical training provided by teaching staff, and two hours of clinical simulation, where the students were able to practice the techniques on professional simulators. At the other two sessions, participants received an explanation of the theoretical aspects of the session, one hour of clinical simulation, and one hour of gamification, in which they had to pass tests based on the performance of practical activities on the subject of the session. At the end of the gamification session, all the participants received a certificate as winners of the “nursing game”.

Results

There was an improvement in the satisfaction and the knowledge level in the gamification sessions. Both were statistically significant (P < 0.001). There was an improvement in the items related to the development of critical thinking and the mobilizing concepts from theory to practice in the gamification sessions.

Conclusion

The intervention was effective in improving the satisfaction of the sessions received and in knowledge development.
The rhizosphere and root selections intensify fungi-bacteria interaction in abiotic stress-resistant plants
Authors: Huang Feng , Lei Mengying , Li Wen
Published: April 2024

The microbial communities, inhabiting around and in plant roots, are largely influenced by the compartment effect, and in turn, promote the growth and stress resistance of the plant. However, how soil microbes are selected to the rhizosphere, and further into the roots is still not well understood. Here, we profiled the fungal, bacterial communities and their interactions in the bulk soils, rhizosphere soils and roots of eleven stress-resistant plant species after six months of growth. The results showed that the root selection (from the rhizosphere soils to the roots) was stronger than the rhizosphere selection (from the bulk soils to the rhizosphere soils) in: (1) filtering stricter on the fungal (28.5% to 40.1%) and bacterial (48.9% to 68.1%) amplicon sequence variants (ASVs), (2) depleting more shared fungal (290 to 56) and bacterial (691 to 2) ASVs measured by relative abundance, and (3) increasing the significant fungi-bacteria crosskingdom correlations (142 to 110). In addition, the root selection, but not the rhizosphere selection, significantly increased the fungi to bacteria ratios (f:b) of the observed species and shannon diversity index, indicating unbalanced effects to the fungal and bacteria communities exerted by the root selection. Based on the results of network analysis, the unbalanced root selection effects were associated with increased numbers of negative interaction (140 to 99) and crosskingdom interaction (123 to 92), suggesting the root selection intensifies the negative fungi-bacteria interactions in the roots. Our findings provide insights into the complexity of crosskingdom interactions and improve the understanding of microbiome assembly in the rhizosphere and roots.
Exam Assessor Tool: An Automated System for Efficient Answer Sheet Evaluation
Authors: Singh Vaibhav Shikhar , Verma Avni , Srivastava Garima , Kumar Sachin
Published: April 2024

With Education 4.0 and four quadrant approach number of innovations have gone into academics for efficient, experiential, and outcome-based education however assessment schemes are still very much dependent on manual assessment methods which are time-consuming and cumbersome. The grading system can sometimes be irrational, with diversified schemes for the same course and can also be biased. Covid 19 pandemic caused a global economic avalanche like we’ve never experienced in our lifetime. Many countries have implemented control measures such as blockades and curfews. The education system in this chaos saw a silver lining with academics shifting to online mode, with paradigm shift in teaching, assessment techniques too need to evolve. Work done is an effort to ease the process of assessment, a machine learning assisted model is developed that automates subjective answer evaluation in the education sector. Our project involved several crucial steps, including grayscale conversion, Natural Language Processing (NLP) for data cleansing, data splitting, and training an artificial neural network (ANN) to predict scores based on extracted features. ANN-based system grades subjective responses without human intervention, reducing the workload of teachers and professors. Model constructed an ANN architecture with three layers using Rectified Linear Activation Unit (ReLU) and Sigmoid activation functions. Trained model was incorporated into a user-friendly web application using the Streamlit library. Model design gives a major boost in grading efficiency and accuracy while providing valuable feedback to students. Research surveys were conducted, and a dataset was constructed for training and testing the model. study yielded an accuracy of 83.14% after employing techniques such as text cleaning, preprocessing, and feature extraction.
Isolation and Characterization of Heavy Metal-Tolerant Bacterial Isolates from Industrial Effluents in Uttar Pradesh, India
Authors: Gangwar Shikha , Tripathi Vijay , Verma Om Prakash
Published: April 2024

Industrial activities over the past century have significantly increased human exposure to pollutants such as heavy metals. Industrial emissions of heavy metals, which are carcinogenic, mutagenic and toxic, contaminate natural water supplies and the agricultural environment. Due to the high concentration of heavy metals in industrial effluents, the bacteria present there naturally develop resistance to heavy metals. The aim of this study is to isolate and characterize bacteria resistant to heavy metal, lead (Pb), copper (Cu), chromium (Cr), cadmium (Cd), and nickel (Ni) from sites contaminated by industrial effluents in Uttar Pradesh, India. A total of 58 bacterial isolates were isolated from 9 samples according to their various morphological parameters and 32 isolates were found positive for all heavy metals, which revealed that samples contained metal-resistant bacterial diversity. Two isolates were identified up to species level based on their physiological, biochemical and molecular characterization as Comamonas testosteroni (S4C1) and Bacillus cereus (S5C3). Both isolates are highly resistant to lead (Pb), copper (Cu), chromium (Cr), cadmium (Cd), and nickel (Ni) and they show different MICs against the above heavy metals at different levels.  A growth experiment showed that the presence of heavy metals concentration had no discernible impact on the growth rate among the isolates. Gel analysis showed interesting patterns of protein expression were observed in the presence of various heavy metals. MALDI-TOF analysis found that specific proteins (S layer protein, F0F1ATP synthase subunit b, Flagellin, 50S ribosomal protein L4, Molecular chaperone) were overexpressed in the presence of heavy metals. As a result, identifying the heavy metal resistance bacteria and their proteins study could be useful as a preliminary investigation for the development of prospective bioremediation agents of potentially hazardous waste treatment technology.
Analysis of Socio-economic Factors on Dry Farming Households of Ananthapuramu District of Andhra Pradesh, India
Authors: Sunayana B. Lydia , Devi K. Uma , Rani Seedari Ujwala , Murthy B. Ramana
Published: April 2024

This study examines the socio-economic profile, household income, and risk aversion behaviour of dry farming households in the Ananthapuramu district of Andhra Pradesh. The research employs a range of analytical tools, including percentages, averages, Lorenz curve, Gini ratios, and multiple linear regression analysis, to investigate income inequalities and risk aversion among farmers. Data was collected through structured questionnaires from 120 randomly selected respondents within the study area. The results revealed that a significant proportion of farmers fell within the age group of 30-39 years (33%), while the majority had attained primary level education (33%). The average family size was 4 to 5 members (68%), comprising 33% males, 31% females, and 35% children. The composition of earners and dependents was found to be 1:1.98, indicating a relatively balanced distribution between those who contributed to household income and those who relied on it. Regarding asset ownership, most farmers possessed land as the primary asset, followed by buildings and implements. The majority of the sampled farmers operated small farms, with 1 to 2 hectares being the prevalent farm size. Income sources were primarily derived from cultivating crops such as groundnut, paddy, cotton, Bengal gram, and tomatoes, alongside income from livestock activities. The study further assessed income inequality using Gini ratios and Lorenz curves. It was found that farmers with less than 1 hectare of land experienced higher income inequality compared to those with larger farms (1-2 hectares and more than 2 hectares). Risk aversion index of the dry farming households was calculated and found to be 3.60 indicating that farmers are risk averters.
The Effect of Tax Avoidance on Cost of Debt with Institutional Ownership as a Moderating Variable (Empirical Study of Energy Sector Companies Listed on The IDX 2020-2022)
Authors: Utami Laila Dyah , Pramiana Omi
Published: April 2024

This research aims to test the effect of tax avoidance on the cost of debt with institutional ownership as a moderating variable. In this research, tax avoidance is measured by the effective tax rate. The population in this research is energy sector companies listed on the Indonesia Stock Exchange for the 2020-2022 period. This type of research is quantitative research. The sample in this research was obtained using purposive sampling, namely selecting samples using predetermined criteria. Based on the purposive sampling method, 57 samples were obtained from 82 energy sector companies listed on the Indonesia Stock Exchange for the 2020-2022 period. The analytical methods used are simple linear regression analysis, Moderated Regression Analysis, partial test (t), and coefficient of determination test (R2) using the SPSS version 16 program. The results of this research show that tax avoidance has a significant negative influence on cost of debt. Institutional ownership can strengthen the tax avoidance and cost of debt variables.
Novel Sol–Gel Synthesis of Acidic MgF2−x(OH)x Materials
Authors: Wuttke Stefan , Coman Simona M. , Scholz Gudrun , Kirmse Holm , Vimont Alexandré , Daturi Maro , Schroeder Sven L. M. , Kemnitz Erhard
Published: November 2008

Novel magnesium fluorides have been prepared by a new fluorolytic sol–gel synthesis for fluoride materials based on aqueous HF. By changing the amount of water at constant stoichiometric amount of HF, it is possible to tune the surface acidity of the resulting partly hydroxylated magnesium fluorides. These materials possess medium‐strength Lewis acid sites and, by increasing the amount of water, Brønsted acid sites as well. Magnesium hydroxyl groups normally have a basic nature and only with this new synthetic route is it possible to create Brønsted acidic magnesium hydroxyl groups. XRD, MAS NMR, TEM, thermal analysis, and elemental analysis have been applied to study the structure, composition, and thermal behaviour of the bulk materials. XPS measurements, FTIR with probe molecules, and the determination of N2/Ar adsorption–desorption isotherms have been carried out to investigate the surface properties. Furthermore, activity data have indicated that the tuning of the acidic properties makes these materials versatile catalysts for different classes of reactions, such as the synthesis of (all‐rac)‐[α]‐tocopherol through the condensation of 2,3,6‐trimethylhydroquinone (TMHQ) with isophytol (IP).
Three‐Dimensional Database Mining Identifies a Unique Chemotype that Unites Structurally Diverse Botulinum Neurotoxin Serotype A Inhibitors in a Three‐Zone Pharmacophore
Authors: Hermone Ann R. , Burnett James C. , Nuss Jonathan E. , Tressler Lyal E. , Nguyen Tam L. , Šolaja Bogdan A. , Vennerstrom Jonathan L. , Schmidt James J. , Wipf Peter , Bavari Sina , Gussio Rick
Published: November 2008

A search query consisting of two aromatic centers and two cationic centers was defined based on previously identified small molecule inhibitors of the botulinum neurotoxin serotype A light chain (BoNT/A LC) and used to mine the National Cancer Institute Open Repository. Ten small molecule hits were identified, and upon testing, three demonstrated inhibitory activity. Of these, one was structurally unique, possessing a rigid diazachrysene scaffold. The steric limitations of the diazachrysene imposed a separation between the overlaps of previously identified inhibitors, revealing an extended binding mode. As a result, the pharmacophore for BoNT/A LC inhibition has been modified to encompass three zones. To demonstrate the utility of this model, a novel three‐zone inhibitor was mined and its activity was confirmed.
Effect of Polymer Composition and Water Content on Proton Conductivity in Vinyl Benzyl Phosphonic Acid—4‐Vinyl Pyridine Copolymers
Authors: Jiang Fengjing , Kaltbeitzel Anke , Fassbender Birgit , Brunklaus Gunther , Pu Hongting , Meyer Wolfgang H. , Spiess Hans W. , Wegner Gerhard
Published: November 2008

The proton conductivities of poly(vinylbenzyl phosphonic acid) (PVBPA) homopolymer and its statistical copolymers with 4‐vinyl pyridine [poly(VBPA‐stat‐4VP)s] are comprehensively studied in this work. Temperature and composition‐dependent “dry” proton conductivities of the copolymers have been determined and the self‐condensation of phosphonic acid groups has been quantified. The results show that the intrinsic proton conductivities of poly(VBPA‐stat‐4VP)s and PVBPA are quite low at 150 °C and exhibit time‐dependent changes due to anhydride formation at elevated temperatures. The effect of polymer composition on proton conduction shows a minimum at a 1:1 molar ratio of proton donor and acceptor groups and is discussed on the basis of the pKa values of the electrolyte species. A trace amount of water significantly increases conductivity probably due to additional hydronium ion diffusion and water bridging effects. Water content and proton conductivities of poly(VBPA‐stat‐4VP)s are determined at different relative humidities. High amounts of water are absorbed at high humidities leading to high proton conductivities.

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Association Among Metabolic Syndrome, Testosterone Level and Severity of Erectile Dysfunction
Authors: Yeh Hsin‐Chih , Wang Chii‐Jye , Lee Yung‐Chin , Hsiao Hsi‐Lin , Wu Wen‐Jeng , Chou Yii‐Her , Huang Chun‐Hsiung
Published: November 2008

The purpose of this study was to determine the influence of metabolic syndrome (MS) and serum testosterone in patients with erectile dysfunction (ED) and their possible association. A total of 103 men with ED were enrolled. The International Index of Erectile Function (IIEF) questionnaire was used to assess erectile condition. MS was defined according to the criteria formulated by the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) and the International Diabetes Federation (IDF). The mean age of the study population was 57.5 ± 10.7 years, with an average IIEF of 14.7 ± 6.7. The age and prevalence of MS using the NCEP ATP III criteria, but not the IDF criteria, were significantly different between mild and moderate/severe ED patients (p = 0.031 and 0.009, respectively). The percentage of hypertension (78.6% vs. 36.2%; p < 0.001) and raised fasting glucose levels (46.4% vs. 19.1%; p = 0.004) were significantly higher in the moderate/severe ED group, and both differences remained significant in multivariate analysis (p = 0.001 and 0.042, respectively). In addition, serum testosterone levels were significantly lower in ED patients with MS (p = 0.002). In summary, the presence of MS is associated with more severe ED. Among the components of MS, elevated blood pressure and fasting blood glucose were independent risk factors. NCEP ATP III criteria seem to correlate better with the degree of ED than the IDF definition. Our results also indicate that MS is associated with a lower testosterone level in patients with ED.
TEL/AML1 Fusion Gene in Childhood Acute Lymphoblastic Leukemia in Southern Taiwan
Authors: Lin Pei‐Chin , Chang Tai‐Tsung , Lin Shiu‐Ru , Chiou Shyh‐Shin , Jang Ren‐Chin , Sheen Jiunn‐Ming
Published: November 2008

Chromosomal abnormalities are found in 80–90% of childhood cases of acute lymphoblastic leukemia (ALL). Leukemia‐specific chromosome aberrations not only have prognostic value, but also provide important clues for further investigation into leukogenesis, leukemic cell transformation, and proliferation. This study used reverse transcriptase–polymerase chain reaction techniques to detect transcripts of the leukemia‐specific chromosome fusion gene, TEL/AML1, and to monitor the expression levels of the TEL‐AML1 fusion transcript in ALL patients at sequential intervals during their treatment course. Twenty‐five ALL patients were enrolled, including 20 who were newly diagnosed and five in relapse. The incidence of the TEL/AML1 fusion gene in this study was 32%. The clinical features of our eight TEL/AML1‐positive ALL cases were similar to those in other studies. Blotting analysis of the levels of the TEL‐AML1 fusion transcript was used to detect minimal residual disease. Reduced levels of TEL/AML1 expression were found in four of the six patients whose bone marrow or peripheral blood samples were obtained after treatment. Further investigation with a larger sample size is warranted.
A Longitudinal Study of Nausea and Vomiting, Fatigue and Perceived Stress in, and Social Support for, Pregnant Women Through the Three Trimesters
Authors: Chou Fan‐Hao , Kuo Shih‐Hsien , Wang Ruey‐Hsia
Published: November 2008

Nausea and vomiting (NV), fatigue, stress and social support during pregnancy have been well documented using cross‐sectional research designs. However, few studies have addressed the patterns and relationships for these variables using a longitudinal research design. The purpose of this study was to examine the patterns of and relationships among NV, fatigue, perceived stress, and social support in pregnant women throughout the three trimesters. A prospective and longitudinal study was conducted from 2003 to 2005. Data were collected on four different measures: the Index of Nausea, Vomiting, and Retching (INVR), the Visual Analog Fatigue Scale (VAFS), the Perceived Stress Scale (PSS), and the Brief Social Support Questionnaire (BSSQ). A total of 91 pregnant women were recruited from prenatal clinics in southern Taiwan. One‐way ANOVA indicated that INVR scores and fatigue were significantly different among the three trimesters, but that perceived stress and social support were not. Post hoc analyses, using least significant difference testing, indicated that the first trimester was associated with significantly higher levels of NV than were the second and third trimesters. The first and third trimesters had significantly higher fatigue levels than did the second trimester. Mixed models indicated that the differences among INVR scores among the three trimesters were independent of gravidity, planned pregnancy and age. The difference in fatigue between the first and second trimesters was independent of gravidity, planned pregnancy and age, but fatigue was positively associated with NV. Perceived stress was positively correlated with NV. However, when further examining the relationships among the key variables by adding fatigue, perceived stress was found to positively correlate with fatigue and not NV, and negatively correlated with social support. The findings of this study provide a more comprehensive understanding and evidence‐based data of the patterns of and relationships among the above four key variables for pregnant women throughout the three trimesters. This will help health care professionals to provide more effective and appropriate care strategies based on the different stages of pregnancy.
Paratesticular Metastasis of Malignant Melanoma: A Case Report
Authors: Acar Omer , Akinci Mustafa , Uluocak Nihat , Akbulut Fatih , Kilicaslan Isin , Gokce Ozgur
Published: November 2008

We report a case of multimetastatic malignant melanoma that was diagnosed after histopathologic examination of the excised paratesticular mass. Our patient initially visited the neurosurgery clinic due to low back pain. After preliminary evaluation, he was referred to our clinic due to a right scrotal mass. We excised the paratesticular mass and testis. The histopathologic findings were consistent with malignant melanoma. He was referred to the oncology department for adjuvant treatment. The patient died during the third month of chemotherapy. Our case was unique because the malignant melanoma was widely metastatic and involved primarily paratesticular tissues without any invasion of the testis and epididymis.
Postoperative Disseminated Intravascular Coagulation in a Patient With Ureteral Metastasis from Gastric Cancer
Authors: Yeh Hsin‐Chih , Hsiao Hsi‐Lin , Chang Tu‐Hao , Wang Sheng‐Lan , Huang Chun‐Hsiung , Wu Wen‐Jeng
Published: November 2008

A 66‐year‐old man, with a history of gastric signet ring cell carcinoma, was admitted due to intermittent dull pain in the left lower abdomen for 3 months. Left ureteral obstruction with suspicious tumor encasement and hydronephrosis was found on imaging studies. Endoscopic ureteral biopsy revealed infiltrating high‐grade urothelial carcinoma. As a result, he underwent left nephroureterectomy and bladder cuff excision. Unexpectedly, metastatic carcinoma of the left ureter from the stomach was the final diagnosis after comparison of the permanent sections of the two specimens. Unfortunately, acute disseminated intravascular coagulation developed and the patient died of disease complications 16 days after the operation, even with intensive care. The details of this rare condition are reported herein with a review of the medical literature.
Sjå på han mannen! On the definiteness and specificity of Scandinavian pronoun demonstratives
Authors: Strahan Tania E.
Published: November 2008

Pronouns with a demonstrative function appear in most of the Scandinavian languages in phrases like Sjå på han mannen ‘Look at that man’. Despite the Scandinavian languages varying in phrase-internal morphosyntactic definiteness agreement requirements generally, the pronoun demonstrative appears universally with a definite noun (phrase). This is accounted for within a Lexical-Functional Grammar framework, where the pronoun demonstrative is treated as carrying the feature [specific = +], and the definite noun (phrase) is the morphosyntactic realisation of underlying specificity also. In addition, there is variation as to whether the pronoun demonstratives occur as a specifier within the NP, or as the head of its own DP, taking an NP object.
High-resolution hard x-ray spectroscopy of high-temperature plasmas using an array of quantum microcalorimeters
Authors: Thorn Daniel B. , Gu Ming F. , Brown Greg V. , Beiersdorfer Peter , Porter F. Scott , Kilbourne Caroline A. , Kelley Richard L.
Published: November 2008

Quantum microcalorimeters show promise in being able to fully resolve x-ray spectra from heavy highly charged ions, such as would be found in hot plasmas with temperatures in excess of 50keV. Quantum microcalorimeter arrays are able to achieve this as they have a high-resolving power and good effective quantum efficiency for hard x-ray photons up to 60keV. To demonstrate this, we present a measurement using an array of thin HgTe quantum microcalorimeters to measure the K-shell spectrum of hydrogenlike through carbonlike praseodymium (Z=57). With this device we are able to attain a resolving power, E∕ΔE, of 1000 at a photon energy of 37keV.
A 300GHz collective scattering diagnostic for low temperature plasmas
Authors: Hardin Robert A. , Scime Earl E. , Heard John
Published: November 2008

A compact and portable 300GHz collective scattering diagnostic employing a homodyne detection scheme has been constructed and installed on the hot helicon experiment (HELIX). Verification of the homodyne detection scheme was accomplished with a rotating grooved aluminum wheel to Doppler shift the interaction beam. The HELIX chamber geometry and collection optics allow measurement of scattering angles ranging from 60° to 90°. Artificially driven ion-acoustic waves are also being investigated as a proof-of-principle test for the diagnostic system.
Time-resolved x-ray and extreme ultraviolate spectrometer for use on the National Spherical Torus Experiment
Authors: Beiersdorfer P. , Lepson J. K. , Bitter M. , Hill K. W. , Roquemore L.
Published: November 2008

We describe upgrades to a compact grazing-incidence spectrometer utilized on the National Spherical Torus Experiment for monitoring light and heavy impurities. A fast-readout charge couple device camera has been implemented that allows the recording of spectra with up to 25ms time integration. This capability is used to study the time evolution of the K-shell emission of hydrogenlike and heliumlike boron, carbon, nitrogen, and oxygen between 10 and 65Å. Different camera positioning pieces have been employed to extend the possible spectral range to as high as 140. Several lines that cannot be ascribed to the usual elements found in the plasma have been observed in this spectral range, although often only in a few isolated discharges.
Z
eff
profile measurement system with an optimized Czerny–Turner visible spectrometer in large helical device
Authors: Zhou H. Y. , Morita S. , Goto M. , Chowdhuri M. B.
Published: November 2008

Z eff measurement system using a visible spectrometer has been newly designed and constructed instead of an old interference filter system to eliminate line emissions from the signal and to measure the Zeff value in low-density plasmas. The system consists of the Czerny–Turner-type spectrometer with a charge-coupled device camera and 44 optical fibers vertical array. The spectrometer is equipped with an additional toroidal mirror for further reduction in the astigmatism in addition to a flat and two spherical mirrors and three gratings (110, 120, and 1200grooves∕mm) with 30cm focal length. The images from 44 optical fibers can be detected without astigmatism in a wavelength range of 200–900nm. Combination of the optical fiber (core diameter: 100μm) with the lens (focal length: 30mm) provides spatial resolution of 30mm at the plasma center. Results clearly indicate a very good focus image of the fiber and suggest the absence of the cross-talk between adjacent fiber images. Absolute intensity calibration has been done using a standard tungsten lamp to analyze the Zeff value. The bremsstrahlung profile and resultant Zeff profile have been obtained after Abel inversion of the signals observed in large helical device plasmas with elliptical poloidal cross section.
Development of backlighting sources for a Compton radiography diagnostic of inertial confinement fusion targets (invited)
Authors: Tommasini R. , MacPhee A. , Hey D. , Ma T. , Chen C. , Izumi N. , Unites W. , MacKinnon A. , Hatchett S. P. , Remington B. A. , Park H. S. , Springer P. , Koch J. A. , Landen O. L. , Seely John , Holland Glenn , Hudson Larry
Published: November 2008

We present scaled demonstrations of backlighter sources, emitting bremsstrahlung x rays with photon energies above 75keV, that we will use to record x-ray Compton radiographic snapshots of cold dense DT fuel in inertial confinement fusion implosions at the National Ignition Facility (NIF). In experiments performed at the Titan laser facility at Lawrence Livermore National Laboratory, we measured the source size and the bremsstrahlung spectrum as a function of laser intensity and pulse length from solid targets irradiated at 2×1017–5×1018W∕cm2 using 2–40ps pulses. Using Au planar foils we achieved source sizes down to 5.5μm and conversion efficiencies of about 1×10−13J∕J into x-ray photons with energies in the 75–100keV spectral range. We can now use these results to design NIF backlighter targets and shielding and to predict Compton radiography performance as a function of the NIF implosion yield and associated background.
Neutron bang time detector based on a light pipe
Authors: Glebov V. Yu. , Moran M. , Stoeckl C. , Sangster T. C. , Cruz M.
Published: November 2008

A neutron bang time detector consisting of a scintillator, light pipe, photomultiplier tube (PMT), and high-bandwidth oscilloscope has been implemented on the 60-beam, 30kJ OMEGA Laser Facility at the University of Rochester’s Laboratory for Laser Energetics. Light from the scintillator, located 23cm from the target, is transmitted from the target bay through a 9.6-m-long, 2in. diameter polished stainless steel pipe to the PMT. The PMT signal is recorded by two channels of a 6GHz, 10GS∕s Tektronix 6604 oscilloscope. The OMEGA optical fiducial pulse train is recorded on the third oscilloscope channel using a fast photodiode to provide the timing reference to the laser. This bang time detector is absolutely temporally calibrated and has been demonstrated to measure the bang time for neutron yields above 1×109 with an accuracy of better than 25ps.
Calculation of low-Z impurity pellet induced fluxes of charge exchange neutral particles escaping from magnetically confined toroidal plasmas
Authors: Goncharov P. R. , Ozaki T. , Sudo S. , Tamura N. , Tolstikhina I. Yu. , Sergeev V. Yu.
Published: November 2008

Measurements of energy- and time-resolved neutral hydrogen and helium fluxes from an impurity pellet ablation cloud, referred to as pellet charge exchange or PCX experiments, can be used to study local fast ion energy distributions in fusion plasmas. The estimation of the local distribution function fi(E) of fast ions entering the cloud requires knowledge of both the fraction F0(E) of incident ions exiting the cloud as neutral atoms and the attenuation factor A(E,ρ) describing the loss of fast atoms in the plasma. Determination of A(E,ρ), in turn, requires the total stopping cross section σloss of neutral atoms in the plasma and the Jacobian reflecting the measurement geometry and the magnetic surface shape. The obtained functions F0(E) and A(E,ρ) enter multiplicatively into the probability density for escaping neutral particle kinetic energy. A general calculation scheme has been developed and realized as a FORTRAN code, which is to be applied for the calculation of fi(E) from PCX experimental results obtained with low-Z impurity pellets.
Photoconductive detectors with fast temporal response for laser produced plasma experiments
Authors: May M. J. , Halvorson C. , Perry T. , Weber F. , Young P. , Silbernagel C.
Published: November 2008

Processes during laser plasma experiments typically have time scales that are less than 100ps. The measurement of these processes requires x-ray detectors with fast temporal resolution. We have measured the temporal responses and linearity of several different x-ray sensitive photoconductive detectors (PCDs). The active elements of the detectors investigated include both diamond (natural and synthetic) and GaAs crystals. The typical time responses of the GaAs PCDs are approximately 60ps, respectively. Some characterizations using x-ray radiation from a synchrotron radiation source are presented.
Observation of plasma density fluctuations by a heavy ion beam probe diagnostic with multiple cell array detector on the tokamak ISTTOK
Authors: Nedzelskiy I. S. , Coelho R. , Alves D. , Silva C. , Fernandes H.
Published: November 2008

The heavy ion beam probe (HIBP) diagnostic permits the measurements of electron density and plasma potential as well as their fluctuations. The use of a multiple cell array detector (MCAD) spreads the HIBP capabilities to make simultaneous measurements across the plasma column. Two sets of current-to-voltage converters with respective bandwidths of 400kHz and 4MHz have been tested. This upgrade of the MCAD electronics has allowed the observation of quasicoherent fluctuations in bulk plasma at frequencies between 100 and 200kHz. The localization and frequency of bulk plasma fluctuations correlate with the magnetohydranamic activity of the plasma.
Probes for measuring fluctuation-induced Maxwell and Reynolds stresses in the edge of the Madison Symmetric Torus reversed field pinch
Authors: Kuritsyn A. , Fiksel G. , Miller M. C. , Almagri A. F. , Reyfman M. , Sarff J. S.
Published: November 2008

Several probes have been constructed to measure fluctuation-induced Maxwell and Reynolds stresses in the edge of the Madison Symmetric Torus reversed field pinch (RFP). The magnetic probe is composed of six magnetic pickup coil triplets. The triplets are separated spatially, which allows for local measurements of the Maxwell stress. To measure the plasma flow components for evaluation of the Reynolds stress, we employ a combination of an optical probe [Kuritsyn et al., Rev. Sci. Indrum. 77, 10F112 (2006)] and a Mach probe. The optical probe measures the radial ion flow locally using Doppler spectroscopy. The Mach probe consists of four current collectors biased negatively with respect to a reference tip and allows for measurements of the poloidal and toroidal components of the bulk plasma flow. The stresses are observed to play an important role in the momentum balance in the RFP edge during internal reconnection events.
Extreme ultraviolet spectroscopy of low-Z ion plasmas for fusion applications
Authors: Wilcox P. G. , Safronova A. S. , Kantsyrev V. L. , Safronova U. I. , Williamson K. M. , Yilmaz M. F. , Clementson J. , Beiersdorfer P. , Struve K. W.
Published: November 2008

The study of impurities is a key component of magnetic fusion research as it is directly related to plasma properties and steady-state operation. Two of the most important low-Z impurities are carbon and oxygen. The appropriate method of diagnosing these ions in plasmas is extreme ultraviolet (EUV) spectroscopy. In this work the results of two different sets of experiments are considered, and the spectra in a spectral region from 40to300Å are analyzed. The first set of experiments was carried out at the Sustained Spheromak Physics Experiment at LLNL, where EUV spectra of oxygen ions were recorded. The second set of experiments was performed at the compact laser-plasma x-ray/EUV facility “Sparky” at UNR. In particular, Mylar and Teflon slabs were used as targets to produce carbon, oxygen, and fluorine ions of different ionization stages. Nonlocal thermodynamic equilibrium kinetic models of O, F, and C were applied to identify the most diagnostically important spectral features of low-Z ions between 40to300Å and to provide plasma parameters for both sets of experiments.
A new fast-ion Dα diagnostic for DIII-D
Authors: Heidbrink W. W. , Luo Y. , Muscatello C. M. , Zhu Y. , Burrell K. H.
Published: November 2008

The fast-ion Dα (FIDA) technique is a charge-exchange recombination spectroscopy measurement that exploits the large Doppler shift of Balmer-alpha light from energetic hydrogenic atoms to infer the fast-ion density. Operational experience with the first dedicated FIDA diagnostic on DIII-D is guiding the design of the second-generation instrument. In the first instrument, dynamic changes in background light associated with plasma instabilities usually dominate measurement uncertainties. Accordingly, the design of the new instrument minimizes scattering of cold Dα light while monitoring its level. The first instrument uses a vertical view to avoid bright interference from the injected-neutral beams. The sightline of the new instrument includes a toroidal component but only measures blueshifted fast-ion light that is Doppler shifted away from the redshifted light of the injected neutrals. The new views are more sensitive to fast ions that circulate in the direction of the plasma current and less sensitive to the trapped-ion and countercirculating populations. Details of the design criteria and solutions are presented.
Radial density profile measurement by using the multichannel microwave interferometer in GAMMA 10
Authors: Yoshikawa M. , Matsumoto T. , Shima Y. , Negishi S. , Miyata Y. , Mizuguchi M. , Imai N. , Yoneda Y. , Hojo H. , Itakura A. , Imai T.
Published: November 2008

Plasma density radial profile measurements are an important study for fusion plasma researches. We reconstructed a multichannel microwave interferometer for radial plasma electron density and density fluctuation measurements with both changing the transmission horn position and using the Teflon lens by only using this system in a single plasma shot. By using this system, we can successfully measure the radial density and density fluctuation spectra in a single plasma shot.
Use of Cherenkov-type detectors for measurements of runaway electrons in the ISTTOK tokamak
Authors: Plyusnin V. V. , Jakubowski L. , Zebrowski J. , Fernandes H. , Silva C. , Malinowski K. , Duarte P. , Rabinski M. , Sadowski M. J.
Published: November 2008

Gas, fluid, or solid Cherenkov-type detectors have been widely used in high-energy physics for determination of parameters of charged particles, which are moving with relativistic velocities. This paper presents experimental results on the detection of runaway electrons using Cherenkov-type detectors in the ISTTOK tokamak discharges. Such detectors have been specially designed for measurements of energetic electrons in tokamak plasma. The technique based on the use of the Cherenkov-type detectors has enabled the detection of energetic electrons (energies higher than 80keV) and determination of their spatial and temporal parameters in the ISTTOK discharges. Obtained experimental data were found in adequate agreement to the results of numerical modeling of the runaway electron generation in ISTTOK.
Investigation of first mirror heating for the collective Thomson scattering diagnostic in ITER
Authors: Salewski M. , Meo F. , Bindslev H. , Furtula V. , Korsholm S. B. , Lauritzen B. , Leipold F. , Michelsen P. K. , Nielsen S. K. , Nonbøl E.
Published: November 2008

Collective Thomson scattering (CTS) has the capabilities to measure phase space densities of fast ion populations in ITER resolved in configuration space, in velocity space, and in time. In the CTS system proposed for ITER, probing radiation at 60GHz generated by two 1MW gyrotrons is scattered in the plasma and collected by arrays of receivers. The transmission lines from the gyrotrons to the plasma and from the plasma to the receivers contain several quasioptical mirrors among other components. These are designed to produce astigmatic beam patterns in the plasma where the beam shapes will have a direct impact on the signal strength of the diagnostic, the spatial resolution, and the robustness of probe and receiver beam overlap against density excursions. The first mirror has a line of sight to the plasma and is thus exposed to severe neutron streaming. The present neutronics and thermomechanical modeling of a first mirror on the high field side indicates that the mirror curvature may warp due to heating. This may alter the beam quality, and therefore, thermal effects have to be accounted for during the design of the mirror. The modeling further demonstrates that thin mirrors are superior to thick mirrors from a thermomechanical point of view.
The motional Stark effect diagnostic for ITER using a line-shift approach
Authors: Foley E. L. , Levinton F. M. , Yuh H. Y. , Zakharov L. E.
Published: November 2008

The United States has been tasked with the development and implementation of a motional Stark effect (MSE) system on ITER. In the harsh ITER environment, MSE is particularly susceptible to degradation, as it depends on polarimetry, and the polarization reflection properties of surfaces are highly sensitive to thin film effects due to plasma deposition and erosion of a first mirror. Here we present the results of a comprehensive study considering a new MSE-based approach to internal plasma magnetic field measurements for ITER. The proposed method uses the line shifts in the MSE spectrum (MSE-LS) to provide a radial profile of the magnetic field magnitude. To determine the utility of MSE-LS for equilibrium reconstruction, studies were performed using the ESC-ERV code system. A near-term opportunity to test the use of MSE-LS for equilibrium reconstruction is being pursued in the implementation of MSE with laser-induced fluorescence on NSTX. Though the field values and beam energies are very different from ITER, the use of a laser allows precision spectroscopy with a similar ratio of linewidth to line spacing on NSTX as would be achievable with a passive system on ITER. Simulation results for ITER and NSTX are presented, and the relative merits of the traditional line polarization approach and the new line-shift approach are discussed.
Suprathermal electron studies in the TCV tokamak: Design of a tomographic hard-x-ray spectrometer
Authors: Gnesin S. , Coda S. , Decker J. , Peysson Y.
Published: November 2008

Electron cyclotron resonance heating and electron cyclotron current drive, disruptive events, and sawtooth activity are all known to produce suprathermal electrons in fusion devices, motivating increasingly detailed studies of the generation and dynamics of this suprathermal population. Measurements have been performed in the past years in the tokamak à configuration variable (TCV) tokamak using a single pinhole hard-x-ray (HXR) camera and electron-cyclotron-emission radiometers, leading, in particular, to the identification of the crucial role of spatial transport in the physics of ECCD. The observation of a poloidal asymmetry in the emitted suprathermal bremsstrahlung radiation motivates the design of a proposed new tomographic HXR spectrometer reported in this paper. The design, which is based on a compact modified Soller collimator concept, is being aided by simulations of tomographic reconstruction. Quantitative criteria have been developed to optimize the design for the greatly variable shapes and positions of TCV plasmas.
A 280GHz single-channel millimeter-wave interferometer system for KSTAR
Authors: Nam Y. U. , Lee K. D.
Published: November 2008

A 280GHz single-channel horizontal millimeter-wave interferometer system has been fabricated and installed for plasma electron density measurements on the Korea Superconducting Tokamak Advanced Research (KSTAR). A retractable cassette system has been adopted for deep positioning of the interferometer system on large cryostat. The cassette system contains a pneumatic vacuum window shutter and a beam focusing module. The focusing module consists of antennas and aluminum concave mirrors, where an incident beam is reflected on a specially designed carbon inner-wall tile. The module enhances receiving beam power and reduces phase errors due to unexpected beam reflections on a vacuum vessel. Microwave components such as oscillators and mixers are located 2m away from cryostat with a shielding box. Intermediate frequency signals generated by mixers are transmitted to a diagnostics room, and the phase difference between these signals is measured using a multifringe counting phase comparator. A beam path analysis has been performed for a triangular beam path geometry. An effective line-integrated density can be deduced from measured line-integrated density with these results. A beam path length error due to plasma refraction effect has been determined with various plasma conditions.
Spectroscopic diagnostics for ablation cloud of tracer-encapsulated solid pellet in LHD
Authors: Tamura N. , Sergeev V. Yu. , Kalinina D. V. , Miroshnikov I. V. , Sato K. , Sharov I. A. , Bakhareva O. A. , Ivanova D. M. , Timokhin V. M. , Sudo S. , Kuteev B. V.
Published: November 2008

In the Large Helical Device (LHD), various spectroscopic diagnostics have been applied to study the ablation process of an advanced impurity pellet, tracer-encapsulated solid pellet (TESPEL). The total light emission from the ablation cloud of TESPEL is measured by photomultipliers equipped with individual interference filters, which provide information about the TESPEL penetration depth. The spectra emitted from the TESPEL ablation cloud are measured with a 250mm Czerny–Turner spectrometer equipped with an intensified charge coupled device detector, which is operated in the fast kinetic mode. This diagnostic allows us to evaluate the temporal evolution of the electron density in the TESPEL ablation cloud. In order to gain information about the spatial distribution of the cloud parameters, a nine image optical system that can simultaneously acquire nine images of the TESPEL ablation cloud has recently been developed. Several images of the TESPEL ablation cloud in different spectral domains will give us the spatial distribution of the TESPEL cloud density and temperature.