bluuebunny/crossref_metadata_2025_split huggingface dataset:
Blob Transport in the Tokamak Scrape‐off‐Layer
Authors: D'Ippolito D. A. , Myra J. R. , Krasheninnikov S. I. , Yu G. Q. , Pigarov A. Yu. 
Published: April 2004

AbstractRecent experimental evidence suggests the importance of fast radial plasma transport in the scrape‐off‐layer (SOL) of tokamaks. The outward transport appears to be convective rather than diffusive, extends into the far SOL, and can produce significant recycling from the main‐chamber walls, partially bypassing the divertor. A plausible theoretical mechanism to explain this phenomenon is the radial transport of “blobs” of locally dense plasma created by turbulent processes. A related process is the inward transport of “holes” of reduced density plasma, which provides a mechanism for rapid inward transport of impurities. The blob model is also consistent with the spatial and temporal intermittency and the non‐Gaussian statistics observed in the SOL plasma. This paper reviews the present status of blob theory, including analytic models and simulations, and discusses the preliminary comparisons of the blob model with experimental data. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Study of the Ionization Rate in the Scrape‐off Layer
Authors: Popova L. , Tskhakaya D. , Kuhn S. , Nickolov T. , Hristov S. , Hristov V. , Kamberov G. , Marichkova H. , Tomova Z. , Vasileva D. 
Published: April 2004

AbstractThe purpose of this work is to study the effect of multi‐step ionization on the tokamak scrape‐of layer (SOL). Using particle‐in‐cell (PIC) simulations we show that this effect strongly influences the divertor plasma. Our results suggest that, at least for high‐recycling regimes, multi‐step ionization should necessarily be included in SOL analysis. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of hydrogen line radiation on the divertor target plate incident heat flux
Authors: Adams M. L. , Scott H. A. 
Published: April 2004

AbstractHydrogen resonance line radiation strongly interacts with the partially ionized plasma at the tokamak edge. As a result of these interactions, a nonlocal plasma energy transport channel opens, altering local atomic level populations by an order‐of‐magnitude, and affecting plasma transport. Understanding the effects of these interactions is essential to the design of future tokamak divertors, but previous models have not self‐consistently treated this physical process. To model the interaction of hydrogen resonance photons with the plasma at the tokamak edge, a partially ionized plasma fluid transport code (PIP) has been developed and integrated into a nonlocal thermodynamics equilibrium (NLTE) code (CRETIN). The partially ionized plasma fluid transport model was derived from kinetic theory and includes the charge‐exchange coupling of ions with neutral atoms, transport of internal atomic energy, as well as effective ionization, recombination, and energy loss rates determined by the NLTE model. We apply PIP and CRETIN to the modeling of an optically thick detached tokamak divertor both with and without the effects of line radiation interactions. While many characteristics of the detached divertor regime remain, e.g. the pressure drops in front of the target plate, several details change. Most importantly for the design of future divertors, line radiation interactions increase the divertor target plate incident plasma heat flux from 0.189 MW/m2to 0.436 MW/m2. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Doppler spectral line shapes in low frequency turbulent plasmas
Authors: Marandet Y. , Capes H. , Godbert‐Mouret L. , Koubiti M. , Stamm R. 
Published: April 2004

AbstractIn this paper we investigate the influence of low frequency, i.e. drift wave like turbulence on the spectral line shapes in magnetized plasmas. The measured spectrum, which is obtained through both spatial and time averaging processes, is shown to contain information on turbulence. Using a statistical description of the turbulent fluctuations, we investigate the effects of density, fluid velocity and temperature fluctuations on the Doppler profile of a spectral line. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determination of edge plasma parameters by a genetic algorithm analysis of spectral line shapes
Authors: Marandet Y. , Genesio P. , Godbert‐Mouret L. , Koubiti M. , Stamm R. , Capes H. , Guirlet R. 
Published: April 2004

AbstractComparing an experimental and a theoretical line shape can be achieved by a Genetic Algorithm (GA) based on an analogy to the mechanics of natural selection. Such an algorithm is able to deal with complex non linear models, and can avoid local minima. We have used this optimization tool in the context of edge plasma spectroscopy, for a determination of the temperatures and fractions of the various populations of neutral deuterium emitting the Dα line in two configurations of Tore Supra: ergodic divertor and toroidal pumped limiter . (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Three‐Dimensional Neutral Transport Simulations of Gas Puff Imaging Experiments
Authors: Stotler D. P. , D'Ippolito D. A. , LeBlanc B. , Maqueda R. J. , Myra J. R. , Sabbagh S. A. , Zweben S. J. 
Published: April 2004

AbstractGas Puff Imaging (GPI) experiments are designed to isolate the structure of plasma turbulence in the plane perpendicular to the magnetic field. Three‐dimensional aspects of this diagnostic technique as used on the National Spherical Torus eXperiment (NSTX) are examined via Monte Carlo neutral transport simulations. The radial width of the simulated GPI images are in rough agreement with observations. However, the simulated emission clouds are angled approximately 15° with respect to the experimental images. The simulations indicate that the finite extent of the gas puff along the viewing direction does not significantly degrade the radial resolution of the diagnostic. These simulations also yield effective neutral density data that can be used in an approximate attempt to infer 2‐D electron density and temperature profiles from the experimental images. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Multi–scale modeling of hydrogen isotope diffusion in graphite
Authors: Warrier M. , Schneider R. , Salonen E. , Nordlund K. 
Published: April 2004

AbstractThe importance of plasma–wall interaction processes for the edge plasma is well known: creation of impurities by different sputtering mechanisms or recycling properties of the walls are examples of processes determining the divertor characteristics and the edge plasma pro.les. To be able to have a better understanding of the plasma–wall interaction process itself, a multi–scale procedure is followed: molecular dynamics calculations resolve the microscopic length scale and deliver quite precise input data for kinetic Monte Carlo calculations (jump frequencies, migration energies, jump step‐sizes) used for meso–scale up to the macroscopic system length. To cover the whole length scale involved – from microscopic up to macroscopic – several subsequent levels of kinetic Monte Carlo are needed, each providing the necessary input data for the next level. With this procedure the corresponding time scales spanning from picoseconds atomic interaction times to wall equilibration times of at least milliseconds will be spanned. Inclusion of a realistic structure model is also important, like for porous graphite where the void structure and orientation of the microcrystallites have to be included. First results of such a multi–scale calculation are presented studying the diffusion of hydrogen isotopes in porous graphite and are compared with experimental results from the literature. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Generating gradients of retinoic acid in the chick embryo: Cyp26C1 expression and a comparative analysis of the Cyp26 enzymes
Authors: Reijntjes Susan , Gale Emily , Maden Malcolm 
Published: April 2004

AbstractWe have cloned a novel retinoic acid (RA) catabolizing enzyme, Cyp26C1, in the chick and describe here its distribution during early stages of chick embryogenesis. It is expressed from stage 4 in the presumptive anterior (cephalic) mesoderm, in a subset of cephalic neural crest cells, the ventral otic vesicle, mesenchyme adjacent to the otic vesicle, the branchial pouches and grooves, a part of the neural retina, and the anterior telencephalon, and shows a dynamic expression in the hindbrain rhombomeres and neuronal populations within them. By examining the distribution of Cyp26C1 in the RA‐free quail embryo, we can determine which of these expression domains is dependent on RA, and it is only the rhombomeric sites that do not appear, suggesting a role for RA in this location. The most striking domain of Cyp26C1 distribution is in the anterior cephalic mesoderm, which is adjacent to the domain of Raldh2 in the trunk mesoderm, but separated from it by a gap dorsal to which the posterior hindbrain will develop. We suggest that a gradient of RA within the mesoderm generated by Raldh2 and catabolized by Cyp26C1 could be responsible for patterning the hindbrain. We have compared this distribution of Cyp26C1 with that of Cyp26A1 and Cyp26B1 in the chick and shown that they generally occupy nonoverlapping sites of expression in the embryo, and as a result, we suggest individual roles for each of the Cyp enzymes in the developing embryo. Developmental Dynamics 230:509–517, 2004. © 2004 Wiley‐Liss, Inc.
Differential regulation of chondrogenic differentiation by the serotonin2B receptor and retinoic acid in the embryonic mouse hindlimb
Authors: Bhasin N. , Kernick E. , Luo X. , Seidel H.E. , Weiss E.R. , Lauder J.M. 
Published: April 2004

AbstractRetinoic acid (RA) synthesizing and metabolizing enzymes are coordinately expressed with serotonin 2B (5‐HT2B) receptors at sites of epithelial–mesenchymal (E‐M) interaction in the mouse embryo (Bhasin et al., 1999). The promoter of the 5‐HT2B receptor contains potential RA response element (RAREs) as well as an AP‐2 site. Because both retinoid and serotonergic signaling have been implicated in the regulation of chondrogenic differentiation, the present study investigated whether these signals may work together to regulate this morphogenetic process in hindlimb bud micromass cultures. Results indicate that 5‐HT promotes [35S]sulfate incorporation (chondrogenic differentiation) by activation of 5‐HT2B receptors, which use the mitogen activated protein kinase (p42 MAPK) signal transduction pathway, whereas RA dose‐dependently inhibits sulfate incorporation and promotes expression of RARβ, which could lead to inhibition of p38 MAPK. No evidence was found to support the possibility that RA negatively regulates expression of 5‐HT2B receptors. Taken together, these results suggest that 5‐HT and RA may act as opposing signals to regulate chondrogenic differentiation in the developing hindlimb, possibly mediated by different MAPK signal transduction pathways. Developmental Dynamics 230:201–209, 2004. © 2004 Wiley‐Liss, Inc.
Short upstream region drives dynamic expression of hypoxia‐inducible factor 1α during Xenopus development
Authors: Sipe Conor W. , Gruber Erika J. , Saha Margaret S. 
Published: April 2004

AbstractHypoxia‐inducible factor 1α (HIF‐1α) plays a central role in regulating oxygen‐dependent gene expression and is involved in a range of pathways implicated in cellular survival, proliferation, and development. While the posttranslational regulation of HIF‐1α is well characterized, the relative importance of its control at the transcriptional level during development remains less clear. Although the mouse and human promoter regions have been analyzed in vitro, to date, there has been no in vivo analysis of any vertebrate HIF‐1α promoter. To investigate the transcriptional regulation of HIF‐1α during development of the amphibian Xenopus laevis, we have described the gene's expression pattern and isolated the xHIF‐1α upstream regulatory regions. We show xHIF‐1α mRNA to be constitutively expressed at low levels throughout embryogenesis, but with significant up‐regulation during gastrula stages, and subsequently, in specific regions of the central nervous system and axial tissues. Our functional analysis using a series of truncated xHIF‐1α promoter constructs demonstrates that a 173‐bp region of the proximal promoter, which is 100% conserved among five allelic variants, is sufficient to drive correct expression in transgenic embryos. Although these results are corroborated by a parallel set of in vitro transfection experiments in a Xenopus cell line, some key differences suggest the importance of using transgenic methods in conjunction with in vitro assays. Developmental Dynamics 230:229–238, 2004. © 2004 Wiley‐Liss, Inc.
E‐cadherin regulates cell movements and tissue formation in early zebrafish embryos
Authors: Babb Sherry G. , Marrs James A. 
Published: April 2004

AbstractE‐cadherin is maternally expressed in most vertebrate species, but its function during early development of the vertebrate embryo proper is unknown. To directly examine E‐cadherin gene (cdh1) function in zebrafish, morpholino oligonucleotides (MOs) that inhibit E‐cadherin protein (Cdh1) expression were injected into embryos. Cdh1 knockdown reduced embryo survival. In early cdh1 MO‐injected embryos, the cleavage plane orientation between blastomeres was irregular and adhesion defects prevented normal compaction. Cdh1 knockdown inhibited epiboly cell movements. Epiboly delay caused yolk cell lysis and produced embryos with a bifurcated embryonic axis. Cdh1 knockdown inhibited gastrulation cell movements, causing defects in convergence and extension. Additionally, prechordal plate derivatives were absent in Cdh1 knockdown embryos even though presumptive prechordal plate markers were induced normally. E‐cadherin mRNA coinjection demonstrated the specificity of cdh1 MO‐induced defects. Our experiments illustrate the importance of cdh1 in regulating morphogenetic cell movements and tissue formation in the early embryo. Developmental Dynamics 230:263–277, 2004. © 2004 Wiley‐Liss, Inc.
Arrested pulmonary alveolar cytodifferentiation and defective surfactant synthesis in mice missing the gene for parathyroid hormone‐related protein
Authors: Rubin Lewis P. , Kovacs Christopher S. , De Paepe Monique E. , Tsai Shu‐Whei , Torday John S. , Kronenberg Henry M. 
Published: April 2004

AbstractParathyroid hormone‐related protein (PTHrP) and PTH/PTHrP receptor expression are developmentally regulated in lung epithelium and adepithelial mesenchyme, respectively. To test the hypothesis that PTHrP is a developmental regulator of terminal airway development, we investigated in vivo and in vitro models of alveolar cytodifferentiation using mice in which the gene encoding PTHrP was ablated by homologous recombination. We have determined that fetal and newborn PTHrP(−/−) lungs showed delayed mesenchymal–epithelial interactions, arrested type II cell differentiation, and reduced surfactant lamellar body formation and pulmonary surfactant production. Embryonic PTHrP(−/−) lung buds cultured in the absence of skeletal constriction or systemic compensating factors also exhibited delayed alveolar epithelial (type II cell) and mesenchymal cytodifferentiation, as well as a >40% inhibition of surfactant phospholipid production (n = 3–5). Addition of exogenous PTHrP to embryonic PTHrP(−/−) lung cultures normalized interstitial cell morphology and surfactant phospholipid production. The importance of PTHrP as an endogenous regulatory molecule in mammalian lung development is supported by the findings that ablation of PTHrP expression in isolated developing lung is sufficient to disrupt normal development of the alveolar ducts and the centriacinar regions. Developmental Dynamics 230:278–289, 2004. © 2004 Wiley‐Liss, Inc.
Rapid triple‐labeling method combining in situ hybridization and double immunocytochemistry
Authors: Lopez‐Sanchez Carmen , Garcia‐Martinez Virginio , Lawson Aaron , Chapman Susan C. , Schoenwolf Gary C. 
Published: April 2004

AbstractA new, rapid method is described for combining in situ hybridization and immunocytochemistry to define cell populations and to map three‐dimensional movements of groups of labeled cells within developing chick embryos. The method allows fluorescently labeled cells to be followed in living embryos and subsequently detected as a permanent reaction product for detailed three‐dimensional analysis by immunocytochemistry in histological serial sections. Cell identity can be ascertained using a specific riboprobe and in situ hybridization. With this approach, the movements of two groups of cells can be mapped simultaneously (using two different fluorescent trackers and, subsequently, two different chromogens for immunocytochemistry) to analyze relative movements within an embryo, and when combined with in situ hybridization with a specific riboprobe for cell identity, allows fate mapping studies to be conducted using molecular criteria, rather than solely at morphological/positional criteria. The improved method enables the investigator to extract substantially more information from individual embryos, maximizing the results obtained from labor‐intensive fate mapping studies. Developmental Dynamics 230:309–315, 2004. © 2004 Wiley‐Liss, Inc.
Positive influence: How leaders get others to see it their way
Authors: Baldwin David , Grayson Curt 
Published: April 2004

AbstractInfluence is an essential component of leadership, especially in today's organizations, which rely less on hierarchy and more on the leader's ability to get buy‐in from others. Attempts to influence can produce three different outcomes: resistance, compliance, and commitment—with the latter, of course, being the most desirable result. Here's a look at the three types of influencing tactics that are most effective at winning commitment.
Visual hallucination in Parkinson's disease with FDG PET
Authors: Nagano‐Saito Atsuko , Washimi Yukihiko , Arahata Yutaka , Iwai Katsushige , Kawatsu Shoji , Ito Kengo , Nakamura Akinori , Abe Yuji , Yamada Takako , Kato Takashi , Kachi Teruhiko 
Published: April 2004

AbstractTo determine the characteristics of cerebral glucose metabolism in Parkinson's disease patients with visual hallucinations, group comparison studies using [18F]fluorodeoxyglucose positron emission tomography were performed. Nondemented Parkinson's disease patients in advanced stages were classified into two groups: (1) patients without visual hallucinations; (2) patients with visual hallucinations. Compared to patients without hallucinations, the relative regional cerebral glucose metabolic rate was greater in the frontal areas in patients with visual hallucinations, and the increase reached a significant level in the left superior frontal gyrus. Relative frontal hypermetabolism may be a feature of Parkinson's disease patients with visual hallucinations. © 2004 Movement Disorder Society
Response of postapoplectic hemichorea/ballism to gpi pallidotomy: Progressive improvement resulting in complete relief
Authors: Yamada Kazumichi , Harada Mikio , Goto Satoshi 
Published: April 2004

AbstractWe report on a 66‐year‐old woman in whom GPi pallidotomy produced progressive and eventually complete relief of hemichorea/ballism (HCB) after a subthalamic hemorrhage. Although choreoballistic movements were unchanged during and immediately after the surgery, the symptoms were gradually improved and consequently abolished by 5 days postoperatively. HCB has never recurred up to the present (9 months follow‐up period). This note is the first report describing detailed postsurgical process in HCB relief after pallidotomy. © 2004 Movement Disorder Society
Functional restoration of acoustic units and adult‐generated neurons after hypothalamic lesion
Authors: Cheng Mei‐Fang , Peng Jing‐Pian , Chen Gang , Gardner Jeffrey P. , Bonder Edward M. 
Published: April 2004

AbstractThe hypothalamus of the adult ring dove contains acoustic units that respond to species‐specific coo vocalization. Loss of nest coo leads to unsuccessful breeding. However, the recovery of nest coo in some doves suggests that these units are capable of self‐renewal. We have previously shown that lesioning the hypothalamus generates the addition of new neurons at the lesioned area. In this study, we sought to determine whether lesion‐induced new neurons are involved in the recovery of coo‐responsive units. We systematically recorded electrical activity in the ventromedial nucleus (VMN) of the hypothalamus, before and after lesion, for varying periods up to 3 months. Recordings were made when the birds were at rest (spontaneous discharge) and when the birds were exposed to acoustic stimulations (evoked discharge). Concurrently, the lesioned area was monitored for changes in cell types by using bromodeoxyuridine (BrdU) to label newly divided cells and NeuN to identify mature neurons. For 1 month after lesion, there was no sign of electrical activity, and only BrdU‐labeled cells were present. When the first electrical activity occurred, it displayed abnormal spontaneous bursting patterns. The mature discharge patterns (both spontaneous and evoked) occurred after detection of BrdU+/NeuN+ double‐labeled cells 2–3 months postlesion and were similar to those found in intact and sham‐lesioned birds. Double‐labeled cells bore morphologic characteristics of a neuron and were confirmed with z‐stack analysis using confocal laser scanning microscopy. Moreover, double‐labeled cells were not stained for glial fibrillary acidic protein (GFAP), suggesting that they were neurons. The number of coo‐responsive units was significantly correlated with that of BrdU+/NeuN+ cells. Furthermore, the marker for recording sites revealed that coo‐responsive units were colocalized with BrdU+/NeuN+ cells. Taken together, the evidence strongly suggests that lesion‐induced addition of new neurons promotes the functional recovery of the adult hypothalamus. © 2004 Wiley Periodicals, Inc. J Neurobiol 60: 197–213, 2004
Myosin Va and kinesin II motor proteins are concentrated in ribosomal domains (periaxoplasmic ribosomal plaques) of myelinated axons
Authors: Sotelo‐Silveira José R. , Calliari Aldo , Cárdenas Magdalena , Koenig Edward , Sotelo José R. 
Published: April 2004

AbstractPeriaxoplasmic ribosomal plaques (PARPs) are discrete ribosome‐containing domains distributed intermittently along the periphery of axoplasm in myelinated fibers. Thus, they are structural formations in which translational machinery is spatially organized to serve as centers of protein synthesis for local metabolic requirements and perhaps repair as well. Because of evidence that RNA is transported to putative PARP domains, involving both microtubule‐ and actin‐based mechanisms, it was of interest to investigate whether cytoskeletal motor proteins exhibit a nonrandom localization within PARP domains. Axoplasm, from large Mauthner fibers and rat or rabbit spinal ventral nerve root fibers, removed from the myelin sheath in the form of an “axoplasmic whole‐mount” was used for this analysis. PARP domains were identified either by specific immunofluorescence of rRNA, ribosomal P antigen, or by nonspecific RNA fluorescence using RNA binding dyes YOYO‐1 or POPO‐1. A polyclonal antibody (pAb) against the motor domain of myosin Va showed prominent nonrandom immunofluorescence labeling in PARP domains. Similarly, monoclonal antibodies (mAb) against kinesin KIF3A and a pan‐specific antikinesin (mAb IBII) also showed a preponderant immunofluorescence in PARP domains. On the other hand, H2, a mAb antikinesin KIF5A, exhibited only random immunofluorescence labeling in axoplasm, as was also the case with pAb antidynein heavy chain immunofluorescence. Several possible explanations for these findings are considered, primary among which is targeted trafficking of translational machinery that results in local accumulation of motor proteins. Additional possibilities are trafficking functions intrinsic to the domain, and/or functions that govern dynamic organizational properties of PARPs. © 2004 Wiley Periodicals, Inc. J Neurobiol 60: 187–196, 2004