bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nanodroplet Cluster Formation in Ionic Liquid Microemulsions
Authors: Gao Yanan , Voigt Andreas , Hilfert Liane , Sundmacher Kai 
Published: June 2008

AbstractA common ionic liquid (IL), 1‐butyl‐3‐methylimidazolium tetrafluoroborate (bmimBF4), is used as polar solvent to induce the formation of a reverse bmimBF4‐in‐toluene IL microemulsion with the aid of the nonionic surfactant Triton X‐100. The swelling process of the microemulsion droplets by increasing bmimBF4 content is detected by dynamic light scattering (DLS), conductivity, UV/Vis spectroscopy, and freeze‐fracture transmission electron microscopy (FF–TEM). The results show that the microemulsion droplets initially formed are enlarged by the addition of bmimBF4. However, successive addition of bmimBF4 lead to the appearance of large‐sized microemulsion droplet clusters (200–400 nm). NMR spectroscopic analysis reveal that the special structures and properties of bmimBF4 and Triton X‐100 together with the polar nature of toluene contribute to the formation of such self‐assemblies. These unique self‐assembled structures of IL‐based microemulsion droplet clusters may have some unusual and unique properties with a number of interesting possibilities for potential applications.
Novel Technique for Direct Measurement of the Plasma Diffusion Coefficient in Magnetized Plasma
Authors: Brotánková J. , Martines E. , Adámek J. , Stöckel J. , Popa G. , Costin C. , Ionita C. , Schrittwieser R. , Van Oost G. 
Published: June 2008

AbstractThe diffusion coefficient in the edge plasma of fusion devices is measured by a new technique. The method is based on studying the decay of the plasma fluctuation spectrum inside the so‐called “Ball‐pen probe”: a small ceramic tube having its mouth flush with a magnetic surface and a movable electrode inside the tube. When the electrode protrudes from the tube, the measured signal shows the floating potential fluctuations of the plasma or the ion saturation current outside the tube. Retracting the electrode into the tube, the power spectrum of the signal displays an exponential decay that is different for different frequencies. Assuming a mainly diffusive behaviour of the plasma inside the tube, the spectrum decay length can be used to derive the value of the diffusion coefficient. The measurements were performed at several radial positions in the CASTOR edge region for three different values of Btor. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Study of Sheath Dynamics in Multicomponent Plasma
Authors: Černý P. , Novák S. , Hrach R. , Bruna P. 
Published: June 2008

AbstractA one‐dimensional self‐consistent particle model for a low‐pressure discharge in an electronegative gas near the cylindrical electrode was developed. The model is based on a deterministic particle‐in‐cell technique with scattering events treated stochastically. The data for the simulation were taken from the simplified model of oxygen‐argon plasma based on a macroscopic kinetic approach. The purpose of the present work was to clarify the role of both electron and individual ions mobilities in the low‐temperature plasma on the dynamics of sheath formation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of Highly Energetic Electrons on Probe Measurements in A Hot Cathode Arc Discharge Plasma
Authors: Ezumi N. 
Published: June 2008

AbstractInfluences of highly energetic electrons on probe measurements has been investigated in a vacuum arc discharge plasma. Double and triple probe measurements clearly show these probe method is very sensitive for the small amount of hot electron component. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Measurements of EEDF in Helium Flowwing Afterglow at Pressures 500 – 2000 PA
Authors: Korolov I. , Plašil R. , Kotrík T. , Dohnal P. , Novotný O. , Glosík J. 
Published: June 2008

AbstractFor measurements of recombination rate coefficients of slowly recombining ions with rate coefficients below 10–7cm3s–1 in Flowing Afterglow Langmuir Probe (FALP) experiment the plasma decay time has to be long and this requires buffer gas (helium) pressures in range 500 – 2000 Pa. Application of Langmuir probe for measurements of electron energy distribution function, EEDF (f (ε)), at these pressures is not trivial. The Druyvestein formula for calculating f (ε) from the second derivative of the electron current to the probe (I″e) cannot be used. More complex analyses of measured probe characteristic are required to obtain reliable EEDF. To characterize the extent of the required corrections, the probe characteristics in well‐defined flowing afterglow plasma were measured and two different methods were used to obtain EEDF. In the first method, the first and second derivative of probe characteristics were used to obtain EEDF [1]. In the second method, numerical correction was calculated [2] and applied to values obtained from Druyvesteyn formula. By comparison of obtained EEDF with Maxwell distribution we determine a region of electron energies where advanced analysis is necessary. It was found that in a helium afterglow at 250 K, with pressure 600 – 2000 Pa, where plasma is nearly Maxwellian with T e ∼ 250 – 600 K, the correction is necessary for electron energies ε ≤ 3.5 kBTe. At higher electron energies correction is negligible and is not necessary. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ion‐Conducting Probes for Low Temperature Plasmas
Authors: Meiss S. A. , Rohnke M. , Rettig F. , Moos R. , Janek J. 
Published: June 2008

AbstractProbes interacting with a low temperature plasma are typically built of electron conducting materials, mostly metals. We apply yttria‐stabilized zirconia (YSZ) which is oxygen ion conducting at elevated temperatures and which is a typical solid electrolyte with high ionic and negligible electronic conductivity. The processes at the plasma|YSZ interface are discussed and first results of measurements with ion‐conducting single‐ and double‐probes in oxygen containing radio frequency plasmas are presented. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Emissive Probe Diagnostics in Low Temperature Plasma – Effect of Space Charge and Variations of Electron Saturation Current
Authors: Marek A. , Jílek M. , Picková I. , Kudrna P. , Tichý M. , Schrittwieser R. , Ionita C. 
Published: June 2008

AbstractWe report a study of electron saturation current variations at varying probe heating that were found to be closely related to probe wire contamination. The study was performed in three types of low temperature argon plasma – the weakly magnetized plasma of a cylindrical magnetron, the non‐magnetized plasma of a double plasma machine and a hollow cathode plasma jet, showing different trends. In the present work the effect of overestimation of the plasma potential by a strongly emitting probe is discussed and experimental data are compared with a theoretical model. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Study of Electronegative Ar/O2 Discharge by Means of Langmuir Probe
Authors: Straňák V. , Blažek J. , Wrehde S. , Adámek P. , Hubička Z. , Tichý M. , Špatenka P. , Hippler R. 
Published: June 2008

AbstractThe paper presents systematic Langmuir probe diagnostic of a dc discharge in Ar/O2 mixture with low fraction of O2, burning in a sputtering planar magnetron. Electron density, electron temperature and plasma potential are investigated in dependence upon experimental conditions like pressure, rate of oxygen, incoming power, and on balanced or unbalanced mode of magnetron. A new method of determining negative‐ion density from the current‐voltage characteristic is proposed. This method is based on comparison of the characteristic measured in electronegative plasma (e.g. Ar/O2) with a reference characteristic scanned in an electropositive counterpart (Ar), existing in similar conditions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Application of Langmuir Probe in Recombination Dominated Afterglow Plasma
Authors: Korolov I. , Kotrík T. , Plašil R. , Varju J. , Hejduk M. , Glosík J. 
Published: June 2008

AbstractNew advanced data analysis method for calculation of recombination rate coefficients from the decay of electron density during the afterglow (along the flow tube) in a Flowing Afterglow Langmuir Probe (FALP) experiment is presented. The method is advantageous for measurements of recombination rate coefficients of slowly recombining ions in conditions where formation of the studied ions is slow, decaying plasma contains several types of ions and the ion formation and recombination proceed simultaneously. The new method is demonstrated on the analysis of the data obtained from plasma decay in He/Kr/H2 and He/Kr/D2 gas mixtures. In a limit for [Kr]/[D2] ≫ 1, the recombination rate coefficients for KrD+ ions α (KrD+, 250 K) = 1 × 108cm3s–1 was obtained. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical Probe Diagnostics of the Hollow Cathode Plasma Jet System for Deposition of TiOx Thin Films
Authors: Virostko P. , Hubička Z. , Čada M. , Adámek P. , Kment Š. , Tichý M. , Jastrabík L. 
Published: June 2008

AbstractMeasurements of positive ion flux to a negatively biased substrate for deposition of TiOx thin films by the hollow cathode plasma jet system are presented. Different methods of obtaining the bias of substrate and measuring the resulting ion flux were used for different bias frequencies. Pulsed DC bias, middle frequency 500 kHz bias, and pulse‐modulated 13.56 MHz RF bias were compared. The measurements were performed for different bias and discharge conditions. Time‐resolved Langmuir probe technique was simultaneously used to observe the basic plasma properties during the ion flux measurements. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis and Characterization of Benzannelated Thienyl Oligomers
Authors: Amaladass Pitchamuthu , Clement J. Arul , Mohanakrishnan Arasambattu K. 
Published: June 2008

AbstractAn array of 1,3‐diarylbenzo[c]thiophenes have been synthesized by the ring‐opening of lactones followed by thionation using Lawesson's reagent with concurrent intramolecular cyclization. Photophysical studies of the various benzo[c]thiophene analogues are presented. The results of a cyclic voltammetric investigation of the benzo[c]thiophenes are also reported.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
The use of cationic surfactants and ionic liquids in the detection of microbial contamination by capillary electrophoresis
Authors: Bao Ye , Lantz Andrew W. , Crank Jeffrey A. , Huang Junmin , Armstrong Daniel W. 
Published: June 2008

AbstractA rapid test of whether a laboratory sample contains any microorganisms is important and necessary for many areas of science and technology. Currently, most of the standard procedures for the detection of aerobic bacteria, anaerobic bacteria and fungi, require the preparation of microbial cultures in respective growth media, which are dramatically slow. Different approaches providing fast analysis such as CE are becoming more desired. To compensate for the natural electrophoretic heterogeneity of microbes, various buffer additives were examined to stack all bacteria and fungi in a sample plug into a single peak. This peak was removed from the molecular contaminants in the sample to prevent false positives. Both cationic surfactants and ionic liquids (IL) were investigated as run buffer additives and they are both widely applicable to different species of bacteria and fungi. Given that high concentrations of surfactants can potentially lyse cells, dicationic IL offer attractive auxiliary buffer additives for use in CE‐based sterility tests. The analysis can be completed in 10 min, thus providing a great advantage over traditional direct inoculation methods that require several weeks to complete.
High‐sensitivity capillary electrophoresis for speciation of organomercury in biological samples using hollow fiber‐based liquid‐liquid‐liquid microextraction combined with on‐line preconcentration by large‐volume sample stacking
Authors: Li Pingjing , Duan Jiankun , Hu Bin 
Published: June 2008

AbstractA hollow fiber‐based liquid‐liquid‐liquid microextraction (HF‐LLLME) combined with on‐line large‐volume sample stacking (LVSS) has been developed for the speciation of organomercury in biological samples by CE with UV detection. Separation was achieved in less than 11 min with an electrolyte consisting of 35 mM sodium tetraborate at pH 9.1. In LVSS, a reverse electrode polarity‐stacking mode (REPSM) was applied as on‐line preconcentration strategy. In HF‐LLLME, the analytes were extracted from 12 mL volume of sample solution (pH adjusted to 3.0) into bromobenzene impregnated in the pores of the hollow fiber, and into an acceptor solution of L‐cysteine (15 μL, 0.02% w/v) inside the hollow fiber. Under the optimized conditions, concentration factors of 2610–4580 were achieved and LODs in the range of 0.03–0.14 μg/L were feasible. The linearity was found to be over two orders of magnitude with correlation coefficient of 0.9991–0.9996. The developed method has been validated using a certified reference material (DORM‐2, dogfish muscle), and the determined values coincided very well with the certified values. The method was also applied to the speciation of organomercury in three kinds of fish samples and human hair samples.
Performance of a damage‐protected beam–column subassembly utilizing external HF2V energy dissipation devices
Authors: Rodgers Geoffrey W. , Solberg Kevin M. , Chase J. Geoffrey , Mander John B. , Bradley Brendon A. , Dhakal Rajesh P. , Li Luoman 
Published: June 2008

AbstractDuctile‐jointed connections, which generally require some form of supplementary energy dissipation to alleviate displacement response, typically employ mild steel energy dissipation devices. These devices run the risk of low‐cycle fatigue, are effective only for peak cycles that exceed prior displacements, are prone to buckling, and may require replacement following an earthquake. This study presents an experimental investigation employing an alternative to mild steel: a high force‐to‐volume (HF2V) class of damper‐based energy dissipation devices. Tests are performed on a near full‐scale beam–column joint subassembly utilizing externally mounted compact HF2V devices. Two configurations are considered: an exterior joint with two seismic beams and one gravity beam framing into a central column, and a corner joint with only one seismic beam and one gravity beam framing into a column. Quasi‐static tests are performed to column drifts up to 4%. The experiments validate the efficacy of the HF2V device concept, demonstrating good hysteretic energy dissipation, and minimal residual device force, allowing ready re‐centring of the joint. The devices dissipate energy consistently on every cycle without the deterioration observed in the yielding steel bar type of devices. The effectiveness of the HF2V devices on structural hysteretic behavior is noted to be sensitive to the relative stiffness of the anchoring elements, indicating that better efficiency would be obtained in an embedded design. Copyright © 2008 John Wiley & Sons, Ltd.
Human catalytic antibody Se‐scFv‐B3 with high glutathione peroxidase activity
Authors: Huo Rui , Wei Jingyan , Xu Junjie , Lv Shaowu , Zheng Qingchuan , Yan Fei , Su Jiaming , Fan Jia , Li Jieshuai , Duan Yujing , Yu Yang , Jin Fenghai , Sun Weiguo , Shi Yi , Cong Dengli , Li Wei , Yan Ganglin , Luo Guimin 
Published: June 2008

AbstractIn order to generate catalytic antibodies with glutathione peroxidase (GPX) activity, we prepared GSH‐S‐2,4‐dinitrophenyl t‐butyl ester (GSH‐S‐DNPBu) as target antigen. Three clones (A11, B3, and D5) that bound specifically to the antigen were selected from the phage display antibody library (human synthetic VH + VL single‐chain Fv fragment (scFv) library). Analysis of PCR products using gel electrophoresis and sequencing showed that only clone B3 beared intact scFv‐encoding gene, which was cloned into the expression vector pPELB and expressed as soluble form (scFv‐B3) in Escherichia coli Rosetta. The scFv‐B3 was purified by Ni2+‐immobilized metal affinity chromatography (IMAC). The yield of purified proteins was about 2.0–3.0 mg of proteins from 1 L culture. After the active site serines of scFv‐B3 were converted into selenocysteines (Secs) with the chemical modification method, we obtained the human catalytic antibody (Se‐scFv‐B3) with GPX activity of 1288 U/µmol. Copyright © 2008 John Wiley & Sons, Ltd.
Nutritional supplements cross‐contaminated and faked with doping substances
Authors: Geyer Hans , Parr Maria Kristina , Koehler Karsten , Mareck Ute , Schänzer Wilhelm , Thevis Mario 
Published: June 2008

AbstractSince 1999 several groups have analyzed nutritional supplements with mass spectrometric methods (GC/MS, LC/MS/MS) for contaminations and adulterations with doping substances.These investigations showed that nutritional supplements contained prohibited stimulants as ephedrines, caffeine, methylenedioxymetamphetamie and sibutramine, which were not declared on the labels. An international study performed in 2001 and 2002 on 634 nutritional supplements that were purchased in 13 different countries showed that about 15% of the nonhormonal nutritional supplements were contaminated with anabolic‐androgenic steroids (mainly prohormones). Since 2002, also products intentionally faked with high amounts of ‘classic’ anabolic steroids such as metandienone, stanozolol, boldenone, dehydrochloromethyl‐testosterone, oxandrolone etc. have been detected on the nutritional supplement market. These anabolic steroids were not declared on the labels either. The sources of these anabolic steroids are probably Chinese pharmaceutical companies, which sell bulk material of anabolic steroids. In 2005 vitamin C, multivitamin and magnesium tablets were confiscated, which contained cross‐contaminations of stanozolol and metandienone. Since 2002 new ‘designer’ steroids such as prostanozol, methasterone, androstatrienedione etc. have been offered on the nutritional supplement market. In the near future also cross‐contaminations with these steroids are expected. Recently a nutritional supplement for weight loss was found to contain the β2‐agonist clenbuterol. The application of such nutritional supplements is connected with a high risk of inadvertent doping cases and a health risk. For the detection of new ‘designer’ steroids in nutritional supplements, mass spectrometric strategies (GC/MS, LC/MS/MS) are presented. Copyright © 2008 John Wiley & Sons, Ltd.
Mass spectrometric determination of gonadotrophin‐releasing hormone (GnRH) in human urine for doping control purposes by means of LC–ESI‐MS/MS
Authors: Thomas Andreas , Geyer Hans , Kamber Matthias , Schänzer Wilhelm , Thevis Mario 
Published: June 2008

AbstractThe decapeptide gonadotrophin‐releasing hormone (GnRH) is endogenously produced in the hypothalamus and secreted into the microcirculation between hypothalamus and pituitary gland. Here, the bioactive hormone is responsible for the release of luteinizing hormone (LH) and follicle‐stimulating hormone (FSH) into the systemic circulation. Because an intermittent application of exogenous GnRH in young males increases the testosterone plasma level by stimulation of the Leydig cells, the potential misuse of the administered substance offers a reasonable relevancy for doping controls and is prohibited in accordance to the list of banned substances of the World Anti‐Doping Agency (WADA).The presented method provides a mass spectrometric approach to determine the nondegraded hormone in regular doping control samples by utilizing a sample preparation procedure with solid phase extraction, immunoaffinity purification and a subsequent separation by liquid chromatography with ESI‐MS/MS detection. For liquid chromatography/mass spectrometry two alternative instrumental equipments were tested: the first consisted of an Agilent 1100 liquid chromatograph coupled to an Applied Biosystem Q Trap 4000 mass spectrometer, the second equipment was assembled by a Waters Aquity nano‐UPLC coupled to a Thermo LTQ Orbitrap high resolution/high accuracy mass spectrometer.In urine specimens provided from healthy volunteers GnRH was not detected in accordance to the recent literature, but in postadministration samples urinary concentrations between 20 to 100 pg/ml of the intact peptide were determined. The method offered good validation results considering the parameter specificity, linearity (5–300 pg/ml), limit of detection (LOD, approx. 5 pg/ml), precision (inter/intraday, < 20%) and accuracy (105%) using Des‐pGlu1‐GnRH as internal standard to control each sample preparation step. Copyright © 2008 John Wiley & Sons, Ltd.
Spectroscopic studies of the corrosion of model iron electrodes in carbonate and phosphate buffer solutions
Authors: Larroumet Damien , Greenfield David , Akid Robert , Yarwood Jack 
Published: June 2008

AbstractWe have extended our unenhanced (non‐SERS) Raman spectroscopic investigations to include a study of the corrosion of an iron electrode in carbonate and phosphate buffer solutions. The measurements have been supported by electrochemical investigations (via cyclic voltammetry), enabling oxidation and reduction reactions to be systematically followed at variable applied potentials.In a carbonate buffer (pH = 9.4) the surface oxidation led to the formation of a ‘green rust’ (a hydrated hydroxy‐carbonate), followed by the α‐ and β‐forms of FeOOH and an underlying magnetite layer formed on the cathodic (reduction) cycle.In a phosphate buffer (pH = 7.7) the surface was passivated by hydrated phosphates of iron [identified as FePO4 · xH2O and Fe3(PO4)2·8H2O]. The formation of oxides (Fe2O3 and Fe3O4) were inferred from voltammetry, but spectral identification was more difficult because of broad, ill‐defined spectra.Despite the challenges of using unenhanced Raman spectroscopy, we believe that the effort was worthwhile, the reactions identified being more likely to be relevant to real electrochemical environments. Copyright © 2008 John Wiley & Sons, Ltd.
Raman spectroscopic study of the tellurite mineral: poughite Fe23+SO4(TeO3)2·3H2O—a multi‐anion mineral
Authors: Frost Ray L. , Keeffe Eloise C. 
Published: June 2008

AbstractPoughite Fe23+SO4(TeO3)2·3H2O, a multi‐anion mineral containing both tellurite and sulfate units has been studied by Raman spectroscopy. Raman bands at 655 cm−1 is attributed to (TeO3)2− stretching bands. The intense sharp Raman band at 1026 cm−1 is assigned to the ν1(SO4)2− symmetric stretching mode, while the bands at 1078, 1152 and 1187 cm−1 are assigned to the ν3(SO4)2− antisymmetric stretching mode. The spectral region 100 to 600 cm−1 displays the bands, which are attributable to the (SO4)2− and (TeO3)2− bending modes. Some evidence from very low intensity Raman bands in the 2800–3600 cm−1 region provides evidence of proton‐tellurite anion interactions. Hydrogen bond distances have been calculated. Copyright © 2008 John Wiley & Sons, Ltd.
Disorder‐induced symmetry lowering in Ba(Y1/2Nb1/2)O3 ceramics probed by Raman spectroscopy
Authors: Dias Anderson , Sá Rodrigo G. , Moreira Roberto L. 
Published: June 2008

AbstractThis work investigates the evolution of the crystal structure of microwave‐hydrothermal synthesized Ba(Y1/2Nb1/2)O3 powders as a function of firing temperature by Raman spectroscopy. The samples were produced at 200 °C and fired at temperatures ranging from 600 to 1600 °C. Raman spectra were obtained at room temperature for all samples and the results showed that materials fired at 1600 °C exhibited tetragonal (I4/m or $C_{4h}^{5}$) structure, whereas those fired at lower temperatures exhibited the triclinic (P1 or Ci1) structure. The results were compared with those observed for ceramics obtained by conventional solid‐state methods. It is believed that the lowering of the symmetry verified in materials fired below 1600 °C is a consequence of the local disorder of Y+3 and Nb+5 ions in octahedral sites. Copyright © 2008 John Wiley & Sons, Ltd.