bluuebunny/crossref_metadata_2025_split huggingface dataset:
Theoretical Study of the Effect of the Dynamic Ergodic Divertor on MARFE Onset
Authors: Kelly F. A. , Tokar M. Z. 
Published: April 2004

AbstractThe effect of the TEXTOR Dynamic Ergodic Divertor (DED) on the formation of Multi‐facetted Asymmetric Radiation From the Edge (MARFE) is investigated. The thermal instability analysis accounts for the poloidal inhomogeneity of the background plasma equilibrium due to the Shafranov shift of the magnetic surfaces and the localized effect of the DED on edge transport and recycling; the influxes of working gas and impurity neutrals determined by plasma‐wall interaction; and the non‐coronal character of the impurity radiation, which depends on the perpendicular transport of impurity neutrals and radiant ion species. The model results in a Sturm‐Liouville eigenvalue equation for the poloidal dependence of perturbations. Numerical results for both carbonized and boronized TEXTOR walls are compared for the poloidally symmetric transport case and for various assumptions regarding poloidally inhomogeneous DED transport and conclude that the DED will decrease the MARFE onset density. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Turbulence in the Divertor Region of Tokamak Edge Plasma
Authors: Umansky M. V. , Rognlien T. D. , Xu X. Q. , Cohen R. H. , Nevins W. M. 
Published: April 2004

AbstractResults of recent modeling of tokamak edge plasma with the turbulence code BOUT are presented. In previous studies with BOUT, the background profiles of plasma density and temperature were set as flux surface functions. However, in the divertor region of a tokamak, the temperature is typically lower and density is higher than those at the mid‐plane. To account for this in the present study, a poloidal variation of background plasma density and temperature is included to provide a more realistic model. For poloidally uniform profiles of the background plasma, the calculated turbulence amplitude peaks near outer mid‐plane, while in the divertor region the amplitude is small. However, present simulations show that as the background plasma profiles become more poloidally non‐uniform, the amplitude of density fluctuations, ñi, starts peaking in the divertor. It is found that in the divertor region the amplitude of ni fluctuations grows approximately linearly with the local density of the background plasma, ni0, while the amplitudes of Te and ϕ fluctuations are positively correlated with the local electron temperature, Te0. Correlation analysis shows that plasma turbulence above and below the x‐point is largerly uncorrelated. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Self‐consistent simulation of turbulence and transport in tokamak edge plasmas
Authors: Rognlien T. D. , Umansky M. V. , Xu X. Q. , Cohen R. H. 
Published: April 2004

AbstractThe status of coupling the fluid 3D turbulence code BOUT and the fluid plasma/neutral 2D transport code UEDGE is reported, where both codes simulate the edge region of diverted tokamaks from several cm inside the magnetic separatrix to the far scrape‐off layer (SOL), thereby including the magnetic X‐point. Because the characteristic time scale of the turbulence is short (∼10−5 − 10−4 s) and the profile evolution time scale can be long (∼10−2 − 10−1 s owing to recycling), an iterative scheme is used that relaxes the turbulent fluxes passed from BOUT to UEDGE and the profiles from UEDGE to BOUT over many coupling steps. Each code is run on its own characteristic time scale, yielding a statistically averaged steady state. For this initial study, the ion and neutral densities and parallel velocities are evolved, while the temperature profiles are stationary. Here the turbulence code is run in the electrostatic approximation. For this example of self‐consistent coupling with strong L‐mode‐like turbulence, the ion flux to the main‐chamber exceeds that to the divertor plates. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Multi‐fluid code simulations including anomalous non‐diffusive transport of plasma and impurities in the tokamak SOL
Authors: Pigarov A. Yu. , Krasheninnikov S. I. , Rognlien T. D. , West W. P. , LaBombard B. , Lipschultz B. , Maingi R. , Soukhanovskii V. 
Published: April 2004

AbstractFast intermittent transport has been observed in the scrape‐off layer (SOL) of major tokamaks including Alcator C‐Mod, DIII‐D, and NSTX. This kind of transport is not diffusive but rather convective. It strongly increases plasma flux to the chamber walls and enhances the recycling of neutral particles in the main chamber. We discuss the anomalous cross‐field convection (ACFC) model for impurity and main plasma ions and its relation to intermittent transport events, i.e. plasma density blobs and holes in the SOL. Along with plasma diffusivity coefficients, our transport model introduces time‐independent anomalous convective velocities across the confining magnetic field. In the discharge modeling, diffusivity coefficients and ACFC velocity profiles are adjusted to match a set of representative experimental data. We use this model in the edge plasma physics code UEDGE to simulate the multi‐fluid two‐dimensional transport for these three tokamaks. We present simulation results suggesting the dominance of anomalous convection in the far SOL transport. These results are consistent with the hypothesis that the chamber wall is an important source of impurities and that different impurity charge states have different magnitude and sign of their anomalous radial convective velocities. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Influence of Impurities and Gas‐Puff on MARFE Evolution in TEXTOR Tokamak
Authors: Zagórski R. , Gerhauser H. , Sergienko G. 
Published: April 2004

AbstractThe 2D multifluid code TECXY is used to study the evolution of so‐called Marfes, thermal instabilities which arise locally in the front of the bumper limiter of the TEXTOR tokamak. The physical model is based on Braginskij‐like equations and incorporates drift motions and currents in a fully self‐consistent way. The radial electric field in the transition layer inside the separatrix is derived from the global ambipolarity condition. We model the bumper region by assuming high additional recombination losses inside this region and a suitably chosen profile for the recycled neutrals penetrating from the bumper surface into the adjacent plasma. A parameter study has been carried out to investigate the influence of impurities and of localized gas‐puffing on the Marfe evolution. Results of numerical simulations are compared with experimental measurements. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Development of heart valve leaflets and supporting apparatus in chicken and mouse embryos
Authors: Lincoln Joy , Alfieri Christina M. , Yutzey Katherine E. 
Published: April 2004

AbstractAbnormalities in valvuloseptal development significantly contribute to congenital heart defects, yet the underlying causes are complex and poorly understood. Early cardiac regulatory genes are differentially expressed during valvuloseptal development, consistent with novel functions during heart chamber formation in chicken and mouse embryos. Distinct valve cell lineages were identified in the leaflets, chordae tendineae, and myotendinous junctions with the papillary muscles based on restricted expression of extracellular matrix molecules. Specific cell types within these structures demonstrate characteristics of chondrogenesis and tendon development, identified byscleraxis, type II collagen, and tenascin expression. In chicken embryos, valve remodeling and maturation accompanies a decrease in mitotic index indicated by reduced bromodeoxyuridine incorporation. Analysis ofTie2‐cre× ROSA26R mice demonstrates that mature valve structures, including the atrioventricular and outflow tract semilunar valve leaflets, chordae tendineae, and the fibrous continuity that connects the septal leaflets of mitral and tricuspid valves, arise from endothelial cells of the endocardial cushions. Together, these studies provide novel insights into the origins and cell lineage diversity of mature valve structures in the developing vertebrate heart. Developmental Dynamics 230:239–250, 2004. © 2004 Wiley‐Liss, Inc.
Construction and analysis of a subtracted library and microarray of cDNAs expressed specifically in chicken heart progenitor cells
Authors: Afrakhte Mozhgan , Schultheiss Thomas M. 
Published: April 2004

AbstractA subtracted library was constructed of genes expressed specifically in the chick precardiac mesoendoderm. The subtracted library was obtained by hybridization of nucleic acids derived from a starting tester library of stage 4–7 chick precardiac mesoendoderm and a starting driver library of stage 2 area pellucida. Approximately 11,000 clones from the resulting subtracted library were printed onto a microarray. Screening of the microarray with probes derived from cardiac and noncardiac tissues, followed by in situ hybridization during chick embryo development, has identified multiple cardiac‐specific genes, including several that have not been characterized previously. The microarray will be useful for future attempts to identify additional novel cardiac‐specific genes, as well as to characterize patterns of gene expression during heart differentiation. Developmental Dynamics 230:290–298, 2004. © 2004 Wiley‐Liss, Inc.
Phase‐shifts in shear stress as an explanation for the maintenance of pool–riffle sequences
Authors: Wilkinson Scott N. , Keller Robert J. , Rutherfurd Ian D. 
Published: April 2004

AbstractThe stability of the pool–rifﬂe sequence is one of the most fundamental features of alluvial streams. For several decades, the process of velocity, or shear stress, reversal has been proposed as an explanation for an increase in the amplitude of pool–rifﬂe sequence bars during high ﬂows, offsetting gradual scour of rifﬂes and deposition in pools during low ﬂows. Despite several attempts, reversal has rarely been recorded in ﬁeld measurements. We propose that, instead of being reversed, maxima and minima in shear stress are phase‐shifted with respect to the pool–rifﬂe sequence bedform proﬁle, so that maximum shear stress occurs upstream of rifﬂe crests at high ﬂow, and downstream at low ﬂow. Such phase‐shifts produce gradients of shear stress that explain rifﬂe deposition, and pool scour, at high ﬂow, in accord with sediment continuity. The proposal is supported by results of a one‐dimensional hydraulic model applied to the surveyed bathymetry of a pool–rifﬂe sequence in a straight reach of a gravel‐bed river. In the sequence studied, the upstream phase‐shift in shear stress at high ﬂow was associated with variations in channel width, with width minima occurring upstream of rifﬂe crests, approximately coincident with shear stress maxima, and width maxima occurring downstream of rifﬂe crests. Assuming that the width variation is itself the result of ﬂow deﬂection by rifﬂe crests at low ﬂow, and associated bank‐toe scour downstream, low and high ﬂow can be seen to have complementary roles in maintaining alluvial pool–rifﬂe sequences. Copyright © 2004 John Wiley & Sons, Ltd.
Effect of α‐tocopherol and N‐acetylcysteine on benzoyl peroxide toxicity in human keratinocytes
Authors: Bellei Elisa , Rota Cristina , Bergamini Stefania , Manfredini Paolo , Albertazzi Alberto , Tomasi Aldo , Iannone Anna 
Published: April 2004

AbstractBenzoyl peroxide is a free‐radical generating compound widely used in the polymer industry and also in pharmaceuticals as antimicrobial agent to treat acne. However, benzoyl peroxide causes irritation and contact dermatitis in about 1% of patients. Concern over the use of this compound is motivated by the demonstration that it can also act as skin tumor promoter in mice. In addition, benzoyl peroxide induces DNA strand breaks in many cells, including keratinocytes. Benzoyl peroxide toxicity is presumably mediated by the formation of reactive free radicals and by the consumption of intracellular antioxidants.In this work we investigated the effect of both the lipophilic antioxidant α‐tocopherol and the hydrophilic thiol donor N‐acetylcysteine (NAC) in human keratinocyte line HaCaT exposed to benzoyl peroxide. A protective effect against benzoyl peroxide cytotoxicity was achieved when cells were grown on a α‐tocopherol layer. On the contrary, the addition of α‐tocopherol dissolved in ethanol had a pro‐oxidant effect, leading to an enhancement of benzoyl peroxide toxicity. Cytotoxicity was also reduced adding NAC to the culture medium; the presence of both NAC and α‐tocopherol exerts a synergis‐ tic cytoprotection. © 2004 Wiley Periodicals, Inc. J Biochem Mol Toxicol 18:107–114, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20008
Benzene metabolism in human lung cell lines BEAS‐2B and A549 and cells overexpressing CYP2F1
Authors: Sheets Patrick L. , Yost Garold S. , Carlson Gary P. 
Published: April 2004

AbstractBenzene is an occupational and environmental toxicant. The main human health concern associated with benzene exposure is leukemia. The toxic effects of benzene are dependent on its metabolism by the cytochrome P450 enzyme system. The cytochrome P450 enzymes CYP2E1 and CYP2F2 are the major contributors to the bioactivation of benzene in rats and mice. Although benzene metabolism has been shown to occur with mouse and human lung microsomal preparations, little is known about the ability of human CYP2F to metabolize benzene or the lung cell types that might activate this toxicant. Our studies compared bronchiolar derived (BEAS‐2B) and alveolar derived (A549) human cell lines for benzene metabolizing ability by evaluating the roles of CYP2E1 and CYP2F1. BEAS‐2B cells that overexpressed CYP2F1 and recombinant CYP2F1 were also evaluated. BEAS‐2B cells overexpressing the enzyme CYP2F1 produced 47.4 ± 14.7 pmols hydroxylated metabolite/106 cells/45 min. The use of the CYP2E1‐selective inhibitor diethyldithiocarbamate and the CYP2F2‐selective inhibitor 5‐phenyl‐1‐pentyne demonstrated that both CYP2E1 and CYP2F1 are important in benzene metabolism in the BEAS‐2B and A549 human lung cell lines. The recombinant expressed human CYP2F1 enzyme had a Km value of 3.83 μM and a Vmax value of 0.01 pmol/pmol P450 enzyme/min demonstrating a reasonably efficient catalysis of benzene metabolism (Vmax/Km = 2.6). Thus, these studies have demonstrated in human lung cell lines that benzene is bioactivated by two lung‐expressed P450 enzymes. © 2004 Wiley Periodicals, Inc. J Biochem Mol Toxicol 18:92–99, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20010
Nitric oxide and oxidative stress in brain and heart of normal rats treated with doxorubicin: Role of aminoguanidine
Authors: Abd El‐Gawad Hanan M. , El‐Sawalhi Maha M. 
Published: April 2004

AbstractDoxorubicin (DOX) is a potent antitumor antibiotic drug known to cause severe cardiac toxicity. Moreover, its adverse effects were found to be extended to the cerebral tissue. Several mechanisms for this toxicity have been ascribed. Currently, one of the most accepted mechanisms is through free radicals; however, the exact role of nitric oxide (NO) is still unclear. Accordingly, a NO‐synthase inhibitor with some antioxidant property, aminoguanidine (AG), was selected to examine its potential protective effect against DOX‐induced toxicity. Male Wistar albino rats (150–200 g) were allocated into a normal control group, DOX‐induced toxicity group, and DOX + AG‐treated group. DOX was injected i.p. at a dose of 10 mg/kg divided into four equal injections over a period of 2 weeks. AG was injected i.p. at a dose of 100 mg/kg 1 h before each DOX injection. The animals were sacrificed 24 h after the last DOX injection and the following parameters were measured: serum lactate dehydrogenase (LDH) and creatine phosphokinase (CPK) activities, cardiac and cerebral contents of malondialdehyde (MDA), conjugated diene (CD), glutathione (GSH), NO, and cytosolic calcium, as well as superoxide dismutase (SOD) and glutathione peroxidase (GSHPX) activities. Cardiotoxicity was manifested by a marked increase in serum LDH and CPK in addition to the sharp increase in MDA reaching eightfolds the basal level. This was accompanied by significant increase in CD, NO, cytosolic calcium, SOD, and GSHPX content/activity by 69, 85, 76, 125, and 41% respectively as compared to normal control. On the other hand, GSH was significantly depressed. In brain, only significant increase in MDA and GSHPX and decrease in GSH were obtained but to a lesser extent than the cardiac tissue. AG treatment failed to prevent the excessive release of cardiac enzymes; however, it alleviated the adverse effects of DOX in heart. AG administration resulted in marked decrease in the elevated levels of MDA, NO, SOD, and GSHPX, however, MDA level was still pathological. The altered parameters in brain were restored by AG. It is concluded that, AG could not provide complete protection against DOX‐induced toxicity. Therefore, it is recommended that, maintenance of the endogenous antioxidant, GSH, and regulation of calcium homeostasis must be considered, rather than NO formation, to guard against DOX‐induced toxicity. © 2004 Wiley Periodicals, Inc. J Biochem Mol Toxicol 18:69–77, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20013
1‐Benzyl‐1,2,3,4‐tetrahydroisoquinoline, a Parkinsonism‐inducing endogenous toxin, increases α‐synuclein expression and causes nuclear damage in human dopaminergic cells
Authors: Shavali Shaik , Carlson Edward C. , Swinscoe John C. , Ebadi Manuchair 
Published: April 2004

Abstract1‐Benzyl‐1,2,3,4‐tetrahydroisoquinoline (1BnTIQ), an endogenous neurotoxin, is known to cause parkinsonism in rodents and nonhuman primates. The levels of 1BnTIQ in cerebrospinal fluid of patients with Parkinson's disease (PD) were reported to be three times higher than those in control subjects. In the present study, we have evaluated the effects of 1BnTIQ on α‐synuclein (α‐syn) expression together with biochemical and morphological changes in human dopaminergic SH‐SY5Y cells in culture. 1BnTIQ at lower concentrations (1–50 μM) increased α‐syn protein expression in a time‐ and dose‐dependent manner in these cells. There was also up‐regulation of α‐syn mRNA by 1BnTIQ. Inhibition of complex I by rotenone and depletion of glutathione by L‐buthionine sulfoxamine also correlated with an increase in α‐syn expression, suggesting that oxidative stress may cause an increase in α‐syn levels in dopaminergic cells. Furthermore, 1BnTIQ significantly depleted glutathione levels. 1BnTIQ at higher concentrations (500 μM) increased reactive oxygen species levels, decreased ATP levels, and caused nuclear damage in the cells. The 1BnTIQ‐induced α‐syn up‐regulation was inhibited by cotreatment with the antioxidants selegiline, coenzyme Q10, and N‐acetylcystein and the caspase inhibitor DEVD‐CHO. Taken together, these results suggest that α‐syn up‐regulation and oxidative stress are contributing factors in 1BnTIQ‐induced neurotoxicity in dopaminergic neurons in PD. © 2004 Wiley‐Liss, Inc.
Implantation of dendritic cells in injured adult spinal cord results in activation of endogenous neural stem/progenitor cells leading to de novo neurogenesis and functional recovery
Authors: Mikami Yuji , Okano Hideyuki , Sakaguchi Masanori , Nakamura Masaya , Shimazaki Takuya , Okano Hirotaka James , Kawakami Yutaka , Toyama Yoshiaki , Toda Masahiro 
Published: April 2004

AbstractWe report a treatment for spinal cord injury involving implantation of dendritic cells (DCs), which act as antigen‐presenting cells in the immune system. The novel mechanisms underlying this treatment produce functional recovery. Among the immune cells tested, DCs showed the strongest activity inducing proliferation and survival of neural stem/progenitor cells (NSPCs) in vitro. Furthermore, in DC‐implanted adult mice, endogenous NSPCs in the injured spinal cord were activated for mitotic de novo neurogenesis. These DCs produced neurotrophin‐3 and activated endogenous microglia in the injured spinal cord. Behavioral analysis revealed the locomotor functions of DC‐implanted mice to have recovered significantly as compared to those of control mice. Our results suggest that DC‐implantation exerts trophic effects, including activation of endogenous NSPCs, leading to repair of the injured adult spinal cord. © 2004 Wiley‐Liss, Inc.
In search of authenticity: Now more than ever, soft skills are needed
Authors: Bunker Kerry , Wakefield Michael 
Published: April 2004

AbstractIn an environment where organizations and their people are experiencing greater and faster change—often highly disruptive change—it's crucial that more emphasis be placed on identifying and developing executives who possess emotional intelligence skills in addition to the more traditional leadership competencies. Among other things, today's leaders need to manage the dynamic tension between a sense of urgency and realistic patience and between optimism and realism and openness.
Impact of dopamine transporter SPECT using 123I‐Ioflupane on diagnosis and management of patients with clinically uncertain parkinsonian syndromes
Authors: Catafau Ana M. , Tolosa Eduardo 
Published: April 2004

AbstractImaging with 123I‐Ioflupane single‐photon emission computed tomography (SPECT) is a marker of nigrostriatal neuronal integrity, allowing differentiation of parkinsonism with loss of dopaminergic terminals (presynaptic Parkinson syndrome [PS]) from parkinsonism without nigrostriatal degeneration. This study assessed SPECT imaging in 118 patients with clinically uncertain parkinsonian syndromes (CUPS). In 36% of patients with presynaptic PS and 54% with nonpresynaptic PS, imaging results were not consistent with the initial diagnosis. After imaging, diagnosis was changed in 52% of patients. All patients with a final diagnosis of presynaptic PS had an abnormal image, whereas 94% of patients with nonpresynaptic PS had a normal scan. Imaging increased confidence in diagnosis, leading to changes in clinical management in 72% of patients. Consequently, visual assessment of 123I‐Ioflupane SPECT may have a significant impact on the clinical management of CUPS patients. © 2004 Movement Disorder Society
Adult‐onset tic disorder, motor stereotypies, and behavioural disturbance associated with antibasal ganglia antibodies
Authors: Edwards Mark J. , Dale Russell C. , Church Andrew J. , Trikouli Eleni , Quinn Niall P. , Lees Andrew J. , Giovannoni Gavin , Bhatia Kailash P. 
Published: April 2004

AbstractThe onset of tics in adulthood is rare and, unlike the childhood variety, there is commonly a secondary environmental cause. We present four cases (1 man, 3 women) with an adult onset tic disorder (mean age of onset, 36 years; range, 27–42 years) associated with the presence of serum antibasal ganglia antibodies (ABGA). One patient had motor tics and unusual motor stereotypies, 2 had multiple motor and vocal tics, and the remaining patient had motor tics only. Concomitant psychiatric disturbance was noted in 3 cases. In 2 cases, there was a close temporal relationship between upper respiratory tract infection and the subsequent onset of tics. Imaging was possible in three cases and was normal in two but revealed a lesion involving the right caudate and lentiform nuclei in the other. We suggest that there might be a causal relationship between ABGA and the clinical syndrome in these cases and that ABGA should be considered as a possible etiology for adult‐onset tics. © 2004 Movement Disorder Society