bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diagnostics Development for Steady State Operation of the Stellarator Wendelstein 7‐X
Authors: Burhenn R. , Baldzuhn J. , Biel W. , Dreier H. , Endler M. , Jimenez‐Gomez R. , Grosser K. , Hartfuss H.J. , Hildebrandt D. , Hirsch M. , König R. , Kornejew P. , Krychowiak M. , Laqua H.P. , Laux M. , Oosterbeek J.W. , Pasch E. , Schneider W. , Thomsen H. , Weller A. , Werner A. , Wolf R. , Zhang D. 
Published: March 2011

AbstractThe gain in experience with long‐pulse operation under fusion relevant plasma conditions is an important step towards successful sustainment of future steady state reactor plasmas. The stellarator Wendelstein 7‐X (W7‐X) [1], presently being under construction, is already equipped with a superconducting coil system and principally capable of quasi‐continuous operation. Like other long pulse devices, W7‐X is faced with new enhanced technical requirements which have to be met by plasma facing components as well as the diagnostic systems in general. Water‐cooled windows were qualified up to 60 kW/m2 thermal load, and shutters against evaporation of sensitive elements outside the attended time of the diagnostic as well as for baseline control had been developed. Shielding of in‐vessel components against damage by absorption of microwave stray radiation originating from the heating systems appears to be one of the most challenging tasks. Experiments using a microwave test chamber identify critical materials and approved the necessity for careful shielding of both, sensitive diagnostics and cables. Spectroscopic systems for monitoring the impurity content and divertor load as well as for robust density measurement are presented (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Towards Intelligent Video Understanding Applied to Plasma Facing Component Monitoring
Authors: Martin V. , Travere J.‐M. , Moncada V. , Brémond F. 
Published: March 2011

AbstractIn this paper, we promote intelligent plasma facing component video monitoring for both real‐time purposes (machine protection issues) and post event analysis purposes (plasma‐wall interaction understanding). We propose a vision‐based system able to automatically detect and classify into different pre‐defined categories thermal phenomena such as localized hot spots or transient thermal events (e.g. electrical arcing) from infrared imaging data of PFCs. This original computer vision system is made intelligent by endowing it with high‐level reasoning (i.e. integration of a priori knowledge of thermal event spatiotemporal properties to guide the recognition), self‐adaptability to varying conditions (e.g. different thermal scenes and plasma scenarios), and learning capabilities (e.g. statistical modelling of event behaviour based on training samples) (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Study of Heating Effects During Thomson Scattering in Laser Induced Plasma in Air
Authors: Travaillé G. , Mendys A. , Dzierzega K. , Pellerin S. , Pokrzywka B. , Thouin E. , Bousquet B. , Canioni L. 
Published: March 2011

AbstractThe laser induced plasma in air produced by 6 ns, 532 nm Nd:YAG pulses with 25 mJ energy was studied using the Thomson scattering method and plasma imaging techniques. Thomson scattering spectra were registered at delay times ranging from 150 ns to 1 µs after the breakdown pulses. The electron density and temperature, as determined in the core of the plasma plume, were found to decrease from 7.4×1017 cm–3 to 1.0×1017 cm–3 and from 101 000 K to 22 700 K, respectively. These electron temperatures were found to result partially from plasma heating. This effect has been observed between the beginning and the end of the probe (Thomson) pulse (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Coherence Imaging of Flows in the DIII‐D Divertor
Authors: Howard J. , Diallo A. , Creese M. , Allen S.L. , Ellis R.M. , Meyer W. , Fenstermacher M.E. , Porter G. D. , Brooks N. H. , Van Zeeland M. E. , Boivin R. L. 
Published: March 2011

AbstractVarious spatial heterodyne polarization interferometers for spectrally‐resolved optical imaging of edge and core parameters in high temperature magnetized plasmas are described. Applications for such “coherence imaging” (CI) systems include imaging motional Stark effect and Zeeman effect polarimetry for determination of the magnetic field pitch angle, and passive and active (charge exchange recombination spectroscopy ‐ CXRS) Doppler imaging of plasma temperature and flow. In this paper we describe spatial heterodyne coherence imaging systems and present first results of Doppler flow imaging in the DIII‐D divertor.Instruments have been installed for imaging flows in the divertor and scrape‐off‐layer in the DIII‐D tokamak and also for Doppler imaging on the H‐1 heliac [1]. In the former case, single snapshot interferometric images of the plasma in CII 514nm, and CIII 465nm emission have been demodulated to obtain flow and ion temperature projections in both the scrape‐off‐layer and divertor. Flow field amplitudes in the divertor are found to be broad agreement with UEDGE modeling [2], and point the way towards experiments that address important divertor transport issues in future (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Novel Diagnostics for Dust in Space, Laboratory and Fusion Plasmas
Authors: Castaldo C. 
Published: March 2011

AbstractIn situ diagnostics for mobile dust, based on dust impact ionization phenomena, as well as silica aerogel dust collectors are discussed for applications to space and fusion plasmas. The feasibility of an electro‐optical probe to detect hypervelocity (>1 km/s) dust particles in tokamaks is evaluated. For quiescent plasmas, a diagnostic of submicron dust based on measurements of plasma fluctuation spectra can be used (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Use of Emissive Probes in Laboratory and Tokamak Plasmas
Authors: Ionita C. , Grünwald J. , Maszl Ch. , Stärz R. , Čerček M. , Fonda B. , Gyergyek T. , Filipič G. , Kovačič J. , Silva C. , Figueiredo H. , Windisch T. , Grulke O. , Klinger T. , Schrittwieser R. 
Published: March 2011

AbstractEmissive probes offer the possibility for a direct determination of the plasma potential since for sufficient electron emission its floating potential is ideally equal to Φpl. By means of two such probes the true electric field can be derived. Emissive probes also deliver reliable results if there are electron drifts and beams in the plasma. A conventional emissive probe consists of an electrically heated loop of refractory wire. We have also developed emissive pin probes of graphite or LaB6, heated by a focused infrared laser beam. In this contribution we first discuss the question to what extent emissive probes perturb the plasma and thereby might falsify the measurement. Furthermore, we present recent measurements with an array of emissive probes in a small tokamak to detect plasma potential fluctuations and electric fields and the related radial plasma transport. Eventually, we present results of a laser‐heated emissive probe in a helicon discharge device (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron Density Determination by Means of Tuneable 50 GHz and 150 GHz Interferometers
Authors: Ehlbeck J. , Rackow K. , Andrasch M. , Weltmann K.‐D. 
Published: March 2011

AbstractThe electron density is one of the most important parameters to characterise the properties of plasma. Among several other methods microwave interferometry is a well known technique. Two approaches at different fre‐quencies are given to show the application of microwave interferometers to practical problems. An interferometer working at a frequency of 150 GHz is used to measure the electron density of an atmospheric pressure microwave torch and the time resolved electron densities in the vicinity of the electrode of commercial fluorescent lamps. A 50 GHz interferometer set up is used to measure the electron density in an inductive coupled plasma at low pressures. The parameters pressure and rf‐power are varied (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Boron Instability in CVD‐Produced Borophosphosilica Films
Authors: Sokolov Yuri V. 
Published: March 2011

AbstractAs‐deposited borophosphosilica glass (BPSG) films undergo substantial relaxation during their storage in air. This work studies a mechanism of dielectric degradation, one effect of which is significant boron out‐gassing at room temperature. This effect is discussed in terms of boron oxide charging when both dopants, B and P, are present in CVD‐produced SiO2. The surface photo‐voltage technique is applied to the oxidized silicon to evaluate charge states on the Si/SiO2/BPSG interfaces after deposition. The characteristic change in the recombination lifetime and the depletion width in silicon subsurface confirms the contribution of charges from the BPSG to the silicon‐oxide interface. The technique presented can be used to estimate the dopant out‐gassing during annealing.
Generation of mice with a conditional allele for the p75NTR neurotrophin receptor gene
Authors: Bogenmann Emil , Thomas Penny S. , Li Qianfeng , Kim Jieun , Yang Liang‐Tung , Pierchala Brian , Kaartinen Vesa 
Published: March 2011

AbstractThe p75NTR neurotrophin receptor has been implicated in multiple biological and pathological processes. While significant advances have recently been made in understanding the physiologic role of p75NTR, many details and aspects remain to be determined. This is in part because the two existing knockout mouse models (Exons 3 or 4 deleted, respectively), both display features that defy definitive conclusions. Here we describe the generation of mice that carry a conditional p75NTR (p75NTR‐FX) allele made by flanking Exons 4–6, which encode the transmembrane and all cytoplasmic domains, by loxP sites. To validate this novel conditional allele, both neural crest‐specific p75NTR/Wnt1‐Cre mutants and conventional p75NTR null mutants were generated. Both mutants displayed abnormal hind limb reflexes, implying that loss of p75NTR in neural crest‐derived cells causes a peripheral neuropathy similar to that seen in conventional p75NTR mutants. This novel conditional p75NTR allele will offer new opportunities to investigate the role of p75NTR in specific tissues and cells. genesis 49:862–869, 2011. © 2011 Wiley‐Periodicals, Inc.
The negative costimulatory molecule PD‐1 modulates the balance between immunity and tolerance via miR‐21
Authors: Iliopoulos Dimitrios , Kavousanaki Melina , Ioannou Marianna , Boumpas Dimitrios , Verginis Panayotis 
Published: March 2011

AbstractDisruption of the programmed death‐1 (PD‐1) pathway leads to breakdown of peripheral tolerance and initiation of autoimmunity. The molecular pathways that mediate this effect remain largely unknown. We report here that PD‐1 knockout (PD‐1−/−) mice develop more severe and sustained Ag‐induced arthritis (AIA) than WT animals, which is associated with increased T‐cell proliferation and elevated levels of IFN‐γ and IL‐17 secretion. MicroRNA analysis of Ag‐specific CD4+ T cells revealed a significant upregulation of microRNA 21 (miR‐21) in PD‐1−/− T cells compared with WT controls. In addition, PD‐1 inhibition, via siRNA, upregulated miR‐21 expression and enhanced STAT5 binding in the miR‐21 promoter area. Computational analysis confirmed that miR‐21 targets directly the expression of programmed cell death 4 (PDCD4) and overexpression of miR‐21 in cells harboring the 3′UTR of PDCD4 resulted in reduced transcription and PDCD4 protein expression. Importantly, in vitro delivery of antisense‐miR‐21 suppressed the Ag‐specific proliferation and cytokine secretion by PD‐1−/− T cells, whereas adoptive transfer of Ag‐specific T cells, overexpressing miR‐21, induced severe AIA. Collectively, our data demonstrate that breakdown of tolerance in PD‐1−/− mice activates a signaling cascade mediated by STAT5, miR‐21, and PDCD4 and establish their role in maintaining the balance between immune activation and tolerance.
Ruthenium–Porphyrin Complexes Induce Apoptosis by Inhibiting the Generation of Intracellular Reactive Oxygen Species in the Human Hepatoma Cell Line (HepG2)
Authors: Liu Yanan , Zhang Xiaonian , Zhang Rong , Chen Tianfeng , Wong Yum‐Shing , Liu Jie , Zheng Wen‐Jie 
Published: March 2011

AbstractTwo ruthenium(II)–porphyrin complexes, [(3‐Py)Ru(phen)2(tmopp)] [1; phen = phenanthroline, tmopp = 5,10,15,20‐tetrakis(4‐methoxyphenyl)porphyrin] and [(4‐Py)Ru(phen)2(tmopp)] (2), have been synthesized and characterized for the first time. It was found that the two ruthenium(II)–porphyrin complexes show significant antitumor activity in HepG2 cells. Flow cytometric analysis showed that complex 1 arrested the cell cycle in the G0/G1 phase and induced apoptosis in HepG2 cells. Fluorescence microscopy and flow cytometric analyses demonstrated that the generation of intracellular reactive oxygen species (ROS) was significantly inhibited in cells treated with either complex. The total antioxidant capacity of the complexes was detected by a 2,2′‐azinobis(3‐ethylbenzthiazoline‐6‐sulfonic acid) (ABTS) assay; this showed that both complexes are good free‐radical scavengers. Ruthenium(II)–porphyrin complex 1 also was found to scavenge hydroxy radicals, as measured by the Fenton system. These data demonstrate that ruthenium(II)–porphyrin complexes exhibit antioxidant properties, probably through the involvement of a direct scavenging effect on a hydroxy radical. Taken together, the findings show that ruthenium(II)–porphyrin complexes induce apoptosis in HepG2 cells by inhibiting the generation of ROS and are potential anticancer therapeutic agents.
Spectroscopic, Structural and DFT Study of the Responses of Carbonylmetal Crown Ether Complexes to Alkali Metal Cations
Authors: Stephenson G. Richard , Anson Christopher E. , Creaser Colin S. , Daul Claude A. 
Published: March 2011

AbstractFTIR spectra of tricarbonyl(η6‐benzo‐15‐crown‐5)chromium(0) (1) in the presence of lithium, sodium and potassium perchlorate salts in methanol show different responses in the Cr–CO vibrational region of the spectrum. Data from the symmetric (νsym) and antisymmetric (νasym) Cr–CO vibrational stretching modes have been analysed by principal component analysis (PCA) to generate a factor score plot that provides a visual representation of these differential responses. X‐ray crystallographic data for the sodium perchlorate complex 1·Na+ and dimensions from DFT‐derived structures of 1·Li+, 1·Na+ and 1·K+ indicate that binding M+ in the crown causes electron density and structural changes in the [O(4)–C(9)–C(4)–O(8)]Cr–C(1)=O(1) sections of 1, which vary depending on the nature of the cation. This suggests a mode of action in which Li+ associates with a more compact O(4)–C(9)–C(4)–O(8), while Na+ and K+ differ crucially in the extent of σ and π contributions to their effect on νsym and νasym. A comparison of the FTIR data from 1, tricarbonyl(η6‐1‐phenyl‐1‐aza‐15‐crown‐5)chromium(0) (2) and tricarbonyl(η6‐2‐phenyl‐15‐crown‐5)chromium(0) (3) with a wider range of cations (NH4+, Li+, Na+, K+, Rb+, Cs+, Mg2+, Ba2+) and anions (AcO–, BPh4–, Br–, C1O4–, I–, SCN–), showed that 1 and 3 both responded significantly to the different metal cations, but 2 did not. The relative cation differentiation of 1, 2 and 3 was measured using the parameter ΔR(cation), and ratios of ΔN(cation) values [calculated from ΔR(cation)] distinguished different effects in the FTIR spectra of 1 and 3 for different pairs of cations.
Intermolecular Hydrogen–Fluorine Interaction in Dimolybdenum Triply Bonded Complexes Modified by Fluorinated Formamidine Ligands for the Construction of 2D‐ and 3D‐Networks
Authors: Krackl Sebastian , Inoue Shigeyoshi , Driess Matthias , Enthaler Stephan 
Published: March 2011

AbstractThe formamidines ArNHC(H)=N–Ar [Ar = Ph (2a), 4‐F‐Ph (2b), 3,5‐F2Ph (2c) and 2,6‐F2Ph (2d) and R = 2,3,5‐F3Ph (2e), 3,4,5‐F3Ph (2f), F5Ph (2g) and 4‐CF3Ph (2h)] were synthesized and the influence of the introduction of a fluorine or a trifluoromethyl group into the aryl unit on the solid‐state structures was investigated. On comparing the experimental data, only marginal differences in the geometrical and electronic features of the diverse substituted species were detected. DFT calculations and X‐ray crystallography of 2d–2g revealed that the E‐syn‐configuration corresponded to the thermodynamically most stable motif of all of the examined formamidines. However, in their solid‐state, these ligands showed a range of H···F interactions, which varied depending on the number and position of the fluorine atoms on the aryl group and thus led to interesting solid‐state structures. Moreover, compounds 2 were used for the synthesis of the new heteroleptic dimolybdenum triply‐bonded complexes, Mo2[(2a–2c; 2e–f)–H]2(OtBu)4 (3a–3c; 3e–3f). X‐ray crystallography of complexes 3c and 3f revealed two different isomers in the solid state: in trans‐3c the two formamidines are in one plane, while in cis‐3c and cis‐3f they are next to each other. The DFT calculations showed only a small distinction in energy between the configurations, which led us to assume that the different configurations were induced by the crystal packing. The specific H···F interactions provided by the different formamidines led to a two‐dimensional arrangement for trans‐3c and a three‐dimensional network for cis‐3c and cis‐3f.
Li2Sr4[Si2N5]N – A Layered Lithium Nitridosilicate Nitride
Authors: Lupart Saskia , Pagano Sandro , Oeckler Oliver , Schnick Wolfgang 
Published: March 2011

AbstractThe quaternary alkaline earth nitridosilicate nitride Li2Sr4[Si2N5]N has been synthesized at 900 °C using liquid lithium as fluxing agent in weld‐shut tantalum ampoules. The structure of Li2Sr4[Si2N5]N {space group I$\bar {4}$m2 [no. 119, a = 751.46(11), c = 1508.9(3) pm, Z = 4, R1 = 0.049, wR2 = 0.135, 499 data, 41 parameters]} is built up from vertex sharing [SiN4] tetrahedra forming layers which can be derived from the apophyllite structure type. According to the condensation degree of κ = 2:5 discrete N3– ions which are coordinated by five Sr2+ and one Li+ site occur besides the silicate layers in the crystal structure. The electronic structure and chemical bonding in Li2Sr4[Si2N5]N has been analyzed by Madelung calculations (MAPLE) and DFT (VASP) calculations.
N‐(Di)icosyl‐Substituted Benzo[a]phenoxazinium Chlorides: Synthesis and Evaluation as Near‐Infrared Membrane Probes
Authors: Naik Sarala , Alves Carla M. A. , Coutinho Paulo J. G. , Gonçalves M. Sameiro T. 
Published: March 2011

AbstractFive benzo[a]phenoxazinium chlorides containing alkyl chains with twenty carbon atoms at the 5‐ or 9‐positions of the tetracyclic ring were efficiently synthesised and characterised by UV/Vis and NIR spectroscopy. The absorption and emission maxima in ethanol occur in the range 627–641 nm and 645–676 nm, respectively, with quantum yields varying from 0.14 to 0.38. Preliminary photophysical studies with these fluorochromophores in zwitterionic [2,3‐bis(palmitoyloxy)propyl‐2‐(trimethylammonio)ethyl phosphate, DPPC] and cationic (N,N‐dimethyl‐N‐octadecyloctadecan‐1‐aminium bromide, DODAB) vesicles were carried out. The results showed that the new benzo[a]phenoxazinium derivatives are able to detect the gel to liquid‐crystalline lipid phase transition through variations in either the extent of H‐aggregation or in the acid–base equilibrium.
Ionizing Power of Aprotic Solvents
Authors: Streidl Nicolas , Mayr Herbert 
Published: March 2011

AbstractRate constants for the heterolysis reactions (SN1) of a series of chloro‐diarylmethanes in aprotic solvents (dimethyl sulfoxide (DMSO), acetonitrile, carboxamides, etc.) have been determined conductometrically in the presence of amines or triphenylphosphane, which trap the intermediate ion‐pairs and suppress ion recombination. The operation of SN2 mechanisms can be excluded because the observed first‐order rate constants become almost independent of the nature of the nucleophilic additive when a certain concentration of nucleophile is exceeded. The heterolysis rate constants are used to calculate nucleofugality parameters Nf and sf for chloride in aprotic solvents according to the linear free‐energy relationship lg k (25 °C) = sf(Nf + Ef). Ionizing powers YBnCl of these solvents were calculated according to the Winstein–Grunwald equation. Because the heterolysis rate constants in aprotic solvents correlate only poorly with dielectric constants or empirical solvent parameters such as Gutmann's acceptor numbers or ETN values, the most common solvent polarity parameters do not reliably predict ionization rates in aprotic solvents.
Facile Access to 3,5‐Dihalogenated Pyrazoles by Sydnone Cycloaddition and their Versatile Functionalization by Pd‐Catalyzed Cross‐Coupling Processes
Authors: Delaunay Thierry , Es‐Sayed Mazen , Vors Jean‐Pierre , Monteiro Nuno , Balme Geneviève 
Published: March 2011

AbstractThe 1,3‐dipolar cycloaddition of diversely N‐substituted 4‐iodosydnones with 3‐halopropiolates produces easily separable mixtures of dihalogenated pyrazolylcarboxylic esters at a preparative scale level, with the 3,5‐dihalogenopyrazole regioisomers always predominating. Further decarboxylation of the major isomers provided the corresponding 3,5‐dihalogenopyrazoles with a free C‐4 position. These were found to be valuable scaffolds for the elaboration of unsymmetrically 1,3,5‐trisubstituted pyrazole derivatives by site‐selective Pd‐catalyzed cross‐coupling reactions. Notably, the flexible and site‐selective introduction of different (hetero)aryl, vinyl, or alkyl substituents at the C‐5 and C‐3 positions of the pyrazole core could be achieved through sequential Suzuki‐type reactions with various boron compounds. Furthermore, the Suzuki coupling sequence could be amenable to a one‐pot procedure that enables rapid generation of the targeted compounds.
Intercalation of Tetrathiafulvalene between the Two Plates of a Copper(I)‐Complexed [4]Rotaxane
Authors: Sauvage Jean‐Pierre , Trolez Yann , Canevet David , Sallé Marc 
Published: March 2011

AbstractThe ability of a cyclic copper(I)‐complexed [4]rotaxane to act as a receptor towards organic electron donors has been studied. In particular, tetrathiafulvalene (TTF), which is a flat and electron‐rich molecule, forms a relatively stable complex with the rotaxane host. 1H NMR spectroscopic measurements strongly suggest that the coordination mode involves intercalation of the TTF motif between the two electron‐poor plates of the [4]rotaxane. By contrast, extended TTF (exTTF), which possesses π‐donating ability similar to that of TTF but which is a significantly bulkier molecule due to a concave structure, was not able to form any detectable complex. This observation tends to indicate that the recognition site of the [4]rotaxane receptor is rigid and can not adapt to thick substrates.
Voltammetric Determination of Both Concentration and Diffusion Coefficient by Combinational Use of Regular and Microelectrodes
Authors: Zhang Hua , Aoki Koichi , Chen Jingyuan , Nishiumi Toyohiko , Toda Hirokazu , Torita Eiji 
Published: March 2011

AbstractTwo Pt disks with 1.6 and 0.1 mm diameter, whose sizes were accurately evaluated, were applied to voltammetric diffusion‐controlled currents to determine the concentrations of redox species. Since voltammetric peak currents at a regular electrode, Ip, and limiting currents at a microelectrode, IL, are proportional to D1/2 and D, respectively, the ratio Ip2/IL is independent of the diffusion coefficient but dependents on the concentration. We used this fact to determine the concentrations of ferrocenyl derivatives, hemin, hexacyanoferrate(II), dioxygen gas and hydrogen gas. New insights are not only the absolute determination of concentrations but also the sensitive detection of adsorption of electrochemical products which blocked the voltammetric currents.