bluuebunny/crossref_metadata_2025_split huggingface dataset:
Monte Carlo Simulations of the Electron Currents Collected by Electrostatic Probes
Authors: Trunec D. , Holík M. , Kudrna P. , Bilyk O. , Marek A. , Hippler R. , Tichý M. 
Published: November 2004

AbstractWe have carried out Monte Carlo simulation of the motion of electrons in the space charge sheath surrounding a cylindrical Langmuir (electrostatic) probe. The electron currents to the probe have been calculated from these simulations for different conditions (pressure of neutral gas, presence of magnetic field). The results of the simulations have been compared with recent Langmuir probe measurements made in cylindrical DC magnetron plasmas. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Angular Resolved Energy and Particle Flux Measurements in a Magnetized Plasma
Authors: Koch B. , Bohmeyer W. , Fussmann G. 
Published: November 2004

AbstractA flat probe allowing simultaneous energy flux and current density measurements as functions of an applied voltage was rotated in a homogeneous plasma. The probe dimensions (a) were larger or comparable to the ion gyro radius (ri).Current density (ji), floating potential (Uf ), energy flux density (q), ion energy reflection coefficient RE and the sheath energy transmission coefficient γ were determined as functions of the angle α between the probe surface normal and the magnetic field. For normal incidence conditions (α = 0) all measured quantities do agree well with the theoretical predictions. With |α| approaching 90°, finite gyro‐radii effects of the ions become important. To lowest order the angular variations can be understood by assuming Γe,i ∝ cos α + 2re,i/a for the ion particle flux density.Most remarkably, a pronounced reduction of the floating potential and the ion impact energy was found experimentally at shallow angles. In contrast, relatively small angular dependencies were found for γ and RE. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Effect of a transverse Magnetic Field on Glow‐Discharge created Electron Beams investigated by Electrical Probes
Authors: Biborosch D.‐L. , Toma M. 
Published: November 2004

AbstractAs known, the hollow cathode discharge has two modes of operation: the usual radial one with low impedance and a high impedance mode in which an axial electron beam is produced. This beam mode occurs at low gas pressures and low discharge currents and the applied discharge voltage determines the energy of the beam electrons. The beam electrons do not suffer collisions with the gas atoms so that they can carry up to 20% of the whole discharge current. In spite of the spatial compression the beam generation does not lead to the pinching of the background discharge.For advanced technologies it is important to investigate whether or not a relatively narrow and weak magnetic field applied transversely to the electric field at the exit of the hollow cathode (like in a magnetron dc discharge) can control the created electron beam. Indeed, it was found that this transverse magnetic field could have an important effect on the breakdown of the high impedance mode and on the corresponding spatial distribution of the generated electron beam. Some new data about this effect which are obtained under these conditions by using electrical probes are discussed in the present contribution. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Radially scanned probe measurements in front of the CASTOR lower hybrid antenna
Authors: Žáček F. , Petržílka V. , Goniche M. , Devynck P. , Nanobashvili S. 
Published: November 2004

AbstractLower hybrid waves (LHW) are used for non‐inductive generation of the electrical current in many tokamaks. However, in addition to the current drive, a parasitic acceleration of particles in front of the antennas takes place if the power is high enough. The small tokamak CASTOR allows to carry out measurements directly in the waves‐plasma interaction region, using movable Langmuir probes. This paper investigates fluctuations of the plasma parameters and electrical fields in the radially narrow layer in front of the CASTOR antenna, where a significant drop of floating potential has been observed recently [1]. Significant changes in these quantities have been found during LHW discharge phase. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Langmuir Probe Measurements in the WEGA Stellarator
Authors: Horvath K. , Lingertat J. , Laux M. , Wagner F. 
Published: November 2004

AbstractLangmuir probe measurements have been performed in weakly magnetized (0.06T < B0 ≤ 0.1T), lowpressure (6.× 10–4Pa ≤ p ≤ 1.0 × 10–2Pa) helium, hydrogen and argon plasmas of the WEGA stellarator. A simple cylindrical graphite probe as well as a double probe were used. The observed characteristics do not show saturation of the ion current. The reason for this anomaly can be the presence of a fast electron component in the plasma caused by the heating method ( ECRH at 2.45 GHz ). Using the model from [5] for derivation of the current to the probe for a two‐temperature Maxwellian electron distribution the characteristics were successfully fitted. Radial profiles of the electron temperature, density and plasma potential as a function of heating power, neutral gas pressure, magnetic field and rotational transform have been obtained. The plasma potential values were compared to results from emissive probe measurements. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Design of a thermal probe for the plasma diagnostics
Authors: Matsuura H. , Michimoto K. 
Published: November 2004

AbstractWhen a solid material is inserted into plasma, it receives heat flux and electrical current according to its bias voltage. The heat flux‐voltage characteristic is more complicated than the current‐voltage characteristic and depend on ion temperature as well as electron temperature. Thermal probe method uses this characteristic to determine plasma parameter. We propose here to use it to deduce ion temperature and show the results on related work. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Measurements of the Parallel and Perpendicular Ion Temperatures by Means of an Ion‐sensitive Segmented Tunnel Probe
Authors: Balan P. , Schrittwieser R. , Adámek J. , Bařina O. , De Beule P. , Ďuran I. , Gunn J. P. , Hrach R. , Hron M. , Ioniţă C. , Martines E. , Pánek R. , Stöckel J. , Van Den Berge G. , Van Oost G. , Van Rompuy T. , Vicher M. 
Published: November 2004

AbstractLocalised ion temperature measurements can only be performed with special electric probes where the electron component of the current is kept off from the collector. In a strong magnetic field the effect can be utilised that the electron gyro‐radius is much smaller than that of the ions. This method was developed by Katsumata and Okazaki (Japan J. Appl. Phys. 6, 123 (1967)). We have used a so‐called tunnel probe (which consists of a conductive tunnel, terminated by an isolated back plate) by adding a diaphragm in front. Thereby the tunnel is prevented from incident electrons at any potential of both electrodes. By sweeping the potential across the tunnel, the perpendicular ion temperature can be inferred. By segmenting the tunnel axially in two parts also the parallel ion temperature can be determined. When the electrodes are biased to ion saturation, the ratio between the ion currents, which reach the first and the second segment, respectively, is a measure for the parallel ion temperature. The dependence of the ratio of the currents has to be determined by a PIC simulation. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Utility of a Baffled Probe for Measurements of Oscillations in Magnetized Plasma
Authors: Demidov V. I. , Finnegan S. M. , Koepke M. E. , Reynolds E. W. 
Published: November 2004

AbstractA baffled probe for distinguishing the oscillations of space potential and temperature in magnetized plasma is tested. The probe consists of a tungsten wire tip, oriented perpendicular to the magnetic field, that is partially shielded by ceramic baffles (masks). The probe works under the condition that the electron Larmor radius is much smaller than the probe radius, and the ion Larmor radius is comparable to or larger than the probe radius. The probe uses the same principles as Katsumata and plug probes, but has the advantage of convenient, realtime controllability of the ratio between electron and ion current while electrically floating, and insensitivity to uncertainties in the orientation of the probe tip relative to the direction of the magnetic field. By rotating the baffle configuration around the probe tip, the ratio between electron and ion probe current and consequently the relative sensitivity of the probe to oscillations of space potential and electron/ion temperature, can be adjusted. Thus, measurements of ac floating potential with different ratio of electron and ion currents allow us to distinguish oscillations of space potential from electron/ion temperature fluctuations. Experiments have been conducted in a fully ionized, barium plasma in the West Virginia University Q‐machine. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of three different staining techniques for intraoperative assessment of nodal metastasis in breast cancer
Authors: Anand Mona , Kumar Rajive , Jain Paresh , Asthana Sonal , Deo S.V.S. , Shukla N.K. , Karak Asis 
Published: November 2004

AbstractImprint cytology has increasingly been used for intraoperative assessment of nodal status in breast cancer. We carried out this study to compare the efficacy of Jenner Giemsa (JG), hematoxylin‐eosin (H&E), and Papanicolaou (Pap) stains for intraoperative lymph node imprint cytology (IIC) in breast cancer. One hundred and seven cases of stage I–III breast cancer were studied. Overall, IIC was accurate in 95.3% cases and had a sensitivity and specificity of 98.5% and 90.0%, respectively. The accuracy of JG (95.3%) was better than that of H&E (90.6%) and Pap (94.0%), although the differences were not statistically significant. Problems encountered included cell loss and drying artifacts with H&E and Pap and the inability to distinguish between tumor cells and histiocytes confidently in tight cellular clusters that were occasionally seen. Opinion was possible in all JG cases, but not in five and four cases by H&E and Pap, respectively. Although the choice of the stain would vary depending on the experience of the pathologist, our work suggests that JG, because of fewer technical problems and superior accuracy, may be preferable over H&E and Pap. Diagn. Cytopathol. 2004;31:423–426. © 2004 Wiley‐Liss, Inc.
Erdheim‐Chester disease of the brain: Cytological features and differential diagnosis of a challenging case
Authors: Rushing Elisabeth J. , Kaplan Keith J. , Mena Hernando , Sandberg Glenn D. , Koeller Kelly , Bouffard John‐Paul 
Published: November 2004

AbstractErdheim‐Chester disease (ECD) is an uncommon, systemic xanthogranulomatous disorder, with distinct clinicopathological features, that is rarely expected preoperatively. We describe a case that presented in the brain of a 26‐yr‐old male patient and clinically mimicked the appearance of a neoplasm. The final diagnosis was a surprise. In retrospect, the diagnosis was suggested by the intraoperative “squash” preparations, which demonstrated a mixed cellular proliferation of lymphohistiocytic elements and large, multinucleated cells with vesicular nuclei, prominent nucleoli, and abundant cytoplasm. To the best of our knowledge, this is the first report detailing the cytopathological features of ECD. Diagn. Cytopathol. 2004;31:420–422. © 2004 Wiley‐Liss, Inc.
Evidence of a right‐shift factor affecting infant hand‐use preferences from 7 to 11 months of age as revealed by latent class analysis
Authors: Michel George F. , Sheu Ching‐Fan , Brumley Michele R. 
Published: November 2004

AbstractInfant hand‐use preferences for apprehending objects were assessed three times at 7, 9, and 11 months of age for 154 infants (79 males) using a reliable and valid procedure. Two classification procedures (differing in Type I classification error rates) were used to identify an infant's preference (right, left, no preference) at each age, and these data were examined using two‐ and three‐group latent class analysis models. These analyses revealed the importance of using a handedness classification procedure with low Type I error rates and evidence of a right‐shift factor similar to that expressed in child and adult handedness. Thus, infant hand‐use preferences for apprehending objects are likely a developmental precursor of adult handedness. The relation of the right‐shift factor to increased susceptibility to social influences during development and the evolution of human abilities also is discussed. © 2002 John Wiley & Sons, Inc. Dev Psychobiol 40: 1–13, 2002
Diurnal cycle in salivary cortisol levels in common marmosets
Authors: Cross Nicola , Rogers Lesley J. 
Published: November 2004

AbstractA noninvasive method of saliva sampling was used to assess the diurnal cortisol rhythm from 0900 to 1700 hr in the common marmoset (Callithrix jacchus). The levels of cortisol were highest in the morning and declined significantly over the day. Individual marmosets varied in the magnitude of the cycle, and the greatest individual variability occurred in the morning levels. The decrease in cortisol levels was more rapid after than before the midday feeding period in subordinate marmosets (aged 53–63 months) compared to dominant marmosets (aged 79–80 months), and overall, the levels of cortisol were higher in the subordinate marmosets. We found no effect of sex on cortisol levels across the cycle. © 2004 Wiley Periodicals, Inc. Dev Psychobiol 45: 134‐139, 2004.
Gene expression in the axolotl germ line: Axdazl, Axvh, Axoct‐4, and Axkit
Authors: Bachvarova Rosemary F. , Masi Thomas , Drum Matthew , Parker Nathan , Mason Ken , Patient Roger , Johnson Andrew D. 
Published: November 2004

AbstractPrimordial germ cells (PGCs) in embryos of mammals and urodele amphibians are formed by induction in the absence of germ plasm. We describe expression of four germ cell‐related genes through the germ cell cycle of the axolotl. The orthologs of vasa and daz‐like are up‐regulated in PGCs of tail bud embryos before the gonad forms and are expressed throughout the female germ cell cycle. Mammalian Oct‐4 is a marker of pluripotency in embryonic cells. Axolotl Oct‐4 has higher homology to Oct‐4 than that found in other vertebrates. It is expressed in the equivalent of the mouse epiblast, in the posterior mesoderm of late gastrulae that gives rise to PGCs, and in diplotene growing oocytes, but not in presumptive PGCs after gastrulation. Finally, a c‐kit homolog is expressed in gonadal oogonia and growing oocytes as in mice but is also not found in PGCs. The expression pattern in urodele gonadal germ cells is similar to that of other vertebrates, although the pattern in pregonadal PGCs is distinctly different from that of mice. We conclude that PGCs are restricted to the germ line later in urodeles than in mice or lack migration and proliferation programs. Developmental Dynamics 231:871–880, 2004. © 2004 Wiley‐Liss, Inc.
FGF‐2 signaling is sufficient to induce dermal condensations during feather development
Authors: Song Hee‐Kyung , Lee So‐Hyung , Goetinck Paul F. 
Published: November 2004

AbstractIn a previous report, we showed that fibroblast growth factor‐2 (FGF‐2) is a signal produced by epidermal placode cells during feather development and that this growth factor can induce feathers in scaleless mutant skins that fail to form feathers due to a defective epidermis (Song et al., [1996] Proc Natl Acad Sci USA 93:10246–10249). Here, we test whether FGF‐2 is sufficient to induce dermal condensations, structures that normally form under the control of signals from the epidermal placode and are identified on the basis of aggregation of cells, the expression of FGF receptor‐1 and bone morphogenetic protein‐2 transcripts and the cessation of proliferation of the condensed cells. By using denuded 8‐day scaleless dermis as a test system, we have established that FGF‐2 is sufficient to induce dermal condensation. We suggest that the primary effect of FGF‐2 is an increase in cellular density mediated through cell migration, followed by the expression of dermal condensation‐specific genes and cessation of cell proliferation. The FGF‐2 effect can be abolished by heparin, suggesting the involvement of heparan sulfate proteoglycans (HSPGs) in growth factor signaling. The spatiotemporal expression of syndecan‐3 during feather development suggests that this cell‐surface HSPG may be involved in the response of competent embryonic skin dermis to FGF‐2. Developmental Dynamics 231:741–749, 2004. © 2004 Wiley‐Liss, Inc.
Fgf signaling induces posterior neuroectoderm independently of Bmp signaling inhibition
Authors: Rentzsch Fabian , Bakkers Jeroen , Kramer Carina , Hammerschmidt Matthias 
Published: November 2004

AbstractWhereas according to the neural default model, neural specification is induced by extracellular inhibitors of bone morphogenetic proteins (Bmps), the role of fibroblast growth factors (Fgfs) during neural induction is heavily debated. Here, we show that, in zebrafish embryos, Bmps and Fgfs play differential roles during the induction and patterning of the anterior vs. the posterior neuroectoderm. Induction of anterior neuroectoderm, giving rise to fore‐ and midbrain, is accomplished by Bmp inhibition, with Fgfs playing a moderate posteriorizing/patterning role, possibly by blocking Bmp signaling at the level of Smad proteins. In contrast, in the posterior‐most neuroectoderm, which is located in marginal regions of the early gastrula embryo to give rise to spinal cord and hindbrain, Fgfs play a neural‐inducing rather than a neural‐patterning role. This Fgf‐dependent posterior neural induction takes place during late blastula and early gastrula stages, after mesoderm has been induced and cannot be blocked by Bmps or the Bmp target gene and downstream effector ΔNp63α, indicating that here, Fgfs act independently of Bmp signaling inhibition. Developmental Dynamics 231:750–757, 2004. © 2004 Wiley‐Liss, Inc.
Dioxovanadium(V) Complexes of ONO Donor Ligands Derived from Pyridoxal and Hydrazides: Models of Vanadate‐Dependent Haloperoxidases
Authors: Maurya Mannar R. , Agarwal Shalu , Bader Cerstin , Rehder Dieter 
Published: November 2004

Abstract[VO(acac)2] reacts with H2L [H2L are the hydrazones H2pydx‐inh (I), H2pydx‐nh (II), or H2pydx‐bhz (III); pydx = pyridoxal, inh = isonicotinohydrazide, nh = nicotinohydrazide, bhz = benzohydrazide] in dry methanol to yield the oxovanadium(IV) complexes [VOL] (H2L = I: 1; H2L = II: 4) or [VO(pydx‐bhz)]. These complexes, when exposed to air, convert into the corresponding dioxovanadium(V) complexes [VO2HL] (H2L = I: 2; H2L = II: 5; H2L = III: 7). Aqueous solutions of vanadate and the ligands at pH = 7.5 give rise to the formation of [K(H2O)3][VO2(pydx‐inh)] (3), [K(H2O)2][VO2(pydx‐nh)] (6) and [K(H2O)2][VO2(pydx‐bhz)] (8). Treatment of 6 and 8 with H2O2 generates the oxo(peroxo)vanadium complexes [VO(O2)L] (H2L = II: 9; H2L = III: 10). Complexes 9 and 10 are capable of transferring an oxo group to PPh3. Acidification of 8 with HCl afforded a hydroxo(oxo) complex. The crystal and molecular structures of ligand I and complex 3 have been solved by single‐crystal X‐ray diffraction. In the anion 3, the vanadium atom is in a distorted tetragonal‐pyramidal environment (τ = 0.23). The K+ ion is coordinated to four water molecules (two of which bridge to a neighbouring K+ ion), the pyridine nitrogen atom of an isonicotinic moiety, the equatorial oxo group of the VO2+ fragment, and the alcoholic group of the pyridoxal moiety, which links adjacent layers in the three‐dimensional lattice network. In the presence of KBr/H2O2, the anionic complexes 3, 6 and 8 catalyse the oxidative bromination of salicylaldehyde in water to 5‐bromosalicylaldehyde in ca. 40% yields with ca. 87% selectivity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
History and rationale of genetic toxicity testing: An impersonal, and sometimes personal, view
Authors: Zeiger Errol 
Published: November 2004

AbstractGenetic toxicity testing is a necessary and pivotal component of product development and registration. This article traces the historical development and evolution of genetic toxicity testing, and the rationale for such testing, and identifies some of the individuals who played key roles in this process. The evolution of the present test batteries and some of the research and rationales behind the decisions to accept or reject tests are described. Environ. Mol. Mutagen., 2004. © 2004 Wiley‐Liss, Inc.
Modelling error and constitutive relations in simulation of flow and transport
Authors: Carey Graham F. , Barth William , Woods Juliette A. , Kirk Benjamin S. , Anderson Michael L. , Chow Sum , Bangerth Wolfgang 
Published: November 2004

AbstractThe main theme of this paper is the modelling error associated with the choice of constitutive equations and associated parameter sensitivity. These key concepts are first discussed in a general way and explored in detail subsequently for three flow application problems which share certain similarities not only in the finite element formulation but also in the nature of the non‐linear constitutive laws that are investigated. The specific flow problems involve: density driven flow in porous media, the Powell–Eyring model for generalized Newtonian flows, and the related Glen's flow type of constitutive relations for glacier modelling. Copyright © 2004 John Wiley & Sons, Ltd.
A fractal forecasting model for financial time series
Authors: Richards Gordon R. 
Published: November 2004

AbstractFinancial market time series exhibit high degrees of non‐linear variability, and frequently have fractal properties. When the fractal dimension of a time series is non‐integer, this is associated with two features: (1) inhomogeneity—extreme fluctuations at irregular intervals, and (2) scaling symmetries—proportionality relationships between fluctuations over different separation distances. In multivariate systems such as financial markets, fractality is stochastic rather than deterministic, and generally originates as a result of multiplicative interactions. Volatility diffusion models with multiple stochastic factors can generate fractal structures. In some cases, such as exchange rates, the underlying structural equation also gives rise to fractality. Fractal principles can be used to develop forecasting algorithms. The forecasting method that yields the best results here is the state transition‐fitted residual scale ratio (ST‐FRSR) model. A state transition model is used to predict the conditional probability of extreme events. Ratios of rates of change at proximate separation distances are used to parameterize the scaling symmetries. Forecasting experiments are run using intraday exchange rate futures contracts measured at 15‐minute intervals. The overall forecast error is reduced on average by up to 7% and in one instance by nearly a quarter. However, the forecast error during the outlying events is reduced by 39% to 57%. The ST‐FRSR reduces the predictive error primarily by capturing extreme fluctuations more accurately. Copyright © 2004 John Wiley & Sons, Ltd.