bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flow threads in surface run‐off: implications for the assessment of flow properties and friction coefficients in soil erosion and hydraulics investigations
Authors: Dunkerley David 
Published: July 2004

AbstractSoil surface microtopography produces non‐uniform surface run‐off, in which narrow threads of relatively deep and fast ﬂow move within broader, shallower, slower‐moving regions. This kind of ﬂow is probably widespread, given that microtopography is itself common. Methods used to record the properties of surface run‐off include grid‐ or transect‐based depth observations, with a single mean ﬂow speed derived by calculation from V = Q/WD, and the use of dye timing to estimate velocity, with an effective mean depth calculated from D = Q/WV.Because these methods allow only single, ﬂow‐ﬁeld mean values to be derived for V or D, neither is well suited to non‐uniform ﬂows. The use of depth data to derive a ﬂow‐ﬁeld mean V furthermore implicitly applies area weighting to the depth data; likewise, the use of dye speeds for V inherently overestimates mean V because dye dominantly follows the faster ﬂow threads. The associated errors in derived parameters such as friction coefﬁcients are not readily quantiﬁed and appear not to have been addressed previously.New ﬁeld experiments made on untilled soil surfaces in arid western NSW, Australia, explore these circumstances and the implications for deriving meaningful measures of ﬂow properties, including friction coefﬁcients. On surfaces deliberately chosen for their very subtle microtopography, average thread velocities are shown to be commonly 2·5 times greater than the ﬂow‐ﬁeld mean, and locally 6–7 times greater. On the other hand, non‐thread ﬂow speeds lie below the ﬂow‐ﬁeld mean, on average reaching only 84 per cent of this value, and often considerably less. Flow‐ﬁeld means conceal the existence of regions of the ﬂow ﬁeld whose properties are statistically distinct. Results conﬁrm that a reliance on ﬂow‐ﬁeld average depths yields estimates of friction coefﬁcients that are biased toward the shallower, high‐roughness parts of the ﬂow, while if dye speeds are relied upon the results are biased toward the deeper, smoother threads of ﬂow. A new approach to the evaluation of friction coefﬁcients in non‐uniform ﬂows is advanced, involving the determination of separate coefﬁcients for threads and non‐thread zones of the ﬂow ﬁeld. In contrast, ﬂow‐ﬁeld friction coefﬁcients as they are customarily derived in run‐off plot experiments subsume these distinct coefﬁcients in proportions that are generally unknown. The value of such coefﬁcients is therefore questionable. Copyright © 2004 John Wiley & Sons, Ltd.
Spatial evaluation of a multi‐class sediment transport and deposition model
Authors: Van Oost K. , Beuselinck L. , Hairsine P. B. , Govers G. 
Published: July 2004

AbstractThis paper presents a model for the description of sediment ﬂuxes and deposition processes in a two‐dimensional spatial context using the multiple‐class Hairsine et al. sediment deposition equations. The model describes size‐selective net deposition as a result of simultaneous deposition by settling and non‐selective re‐entrainment of previously deposited sediment. A critical comparison of ﬁeld observations of net erosion and deposition in a watershed with complex topography with this physically based model is presented. The evaluation shows that the deposition model is capable of simulating reasonably both the observed size selectivity and spatial patterns of the deposition process. In this ﬁeld study, the zone where a net deposit of sediment is re‐entrained by overland ﬂow was predicted to be quite limited spatially due to low sediment concentrations and the absence of aggregates in the eroded soil. Copyright © 2004 John Wiley & Sons, Ltd.
Rate of sediment yield following small‐scale volcanic eruptions: a quantitative assessment at the Merapi and Semeru stratovolcanoes, Java, Indonesia
Authors: Lavigne Franck 
Published: July 2004

AbstractSediment yields were calculated on the ﬂanks of Merapi and Semeru volcanoes in Java, Indonesia, using two different methods. During the ﬁrst year following the 22 November 1994 eruption of Merapi, a sediment yield in excess of 1·5 × 105 m3 km−2 yr−1 was calculated in the Boyong River drainage basin, based on the volumes of sediment that were trapped by ﬁve check dams. At Semeru, sediment discharges were assessed in the Curah Lengkong River from direct measurements on the lahars in motion and on the most signiﬁcant streamﬂows. The calculated rate of sediment yield during one year of data in 2000 was 2·7 × 105 m3 km−2 yr−1.Sediment yields are dominated by rain‐triggered lahars, which occur every rainy season in several drainage basins of Merapi and Semeru volcanoes, mostly during the rainy season extending from October to April. The return period of lahars carrying sediment in excess of 5 × 105 m3 is about one year in the Curah Lengkong River at Semeru. At Merapi, the volume of sediments transported by a lahar did not exceed 2·8 × 105 m3 in the Boyong River during the rainy season 1994–95.On both volcanoes, the sediments are derived from similar sources: pyroclastic‐ﬂow/surges deposits, rockfalls from the lava domes, and old material from the riverbed and banks. However, daily explosions of vulcanian type at Semeru provide a more continuous sediment supply than at Merapi. Therefore, sediment yields are larger at Semeru. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis of stable isotope labeled PNU‐95666
Authors: Jian Zhigang 
Published: July 2004

AbstractStudies towards the synthesis of stable isotope labeled PNU‐95666, a CNS agent currently under development for the treatment of Parkinson's disease, is described. The synthesis of non‐labeled PNU‐95666 starts using a large excess of methylamine. While the non‐labeled methylamine is inexpensive and in plentiful supply, the stable isotope labeled form is expensive and limited availability. Different synthetic routes and conditions, including the use of different aminating agents and various amounts of methylamine were explored and new synthetic conditions were established. Copyright © 2004 John Wiley & Sons, Ltd.
HLA‐DRB1*1501 risk association in multiple sclerosis may not be related to presentation of myelin epitopes
Authors: Finn Thomas P. , Jones Richard E. , Rich Cathleen , Dahan Rony , Link Jason , David Chella S. , Chou Yuan K. , Offner Halina , Vandenbark Arthur A. 
Published: July 2004

AbstractSusceptibility to multiple sclerosis (MS) is associated genetically with human leucocyte antigen (HLA) class II alleles, including DRB1*1501, DRB5*0101, and DQB1*0602, and it is possible that these alleles contribute to MS through an enhanced ability to present encephalitogenic myelin peptides to pathogenic T cells. HLA‐DRB1*1502, which contains glycine instead of valine at position 86 of the P1 peptide‐binding pocket, is apparently not genetically associated with MS. To identify possible differences between these alleles in their antigen‐presenting function, we determined if T‐cell responses to known DRB1*1501‐restricted myelin peptides might be diminished or absent in transgenic (Tg) DRB1*1502‐expressing mice. We found that Tg DRB1*1502 mice had moderate to strong T‐cell responses to several myelin peptides with favorable DRB1*1501 binding motifs, notably myelin oligodendrocyte glycoprotein (MOG)‐35‐55 (which was also encephalitogenic), proteolipid protein (PLP)‐95‐116, and MOG‐194‐208, as well as other PLP and MOG peptides. These peptides, with the exception of MOG‐194‐208, were also immunogenic in healthy human donors expressing either DRB1*1502 or DRB1*1501. In contrast, the DRB1*1502 mice had weak or absent responses to peptides with unfavorable DRB1*1501 binding motifs. Overall, none of the DRB1*1501‐restricted myelin peptides tested selectively lacked immunogenicity in association with DRB1*1502. These results indicate that the difference in risk association with MS of DRB1*1501 versus DRB1*1502 is not due to a lack of antigen presentation by DRB1*1502, at least for this set of myelin peptides, and suggest that other mechanisms involving DRB1*1501 may account for increased susceptibility to MS. © 2004 Wiley‐Liss, Inc.
Failure of neuronal protection by inhibition of glial activation in a rat model of striatonigral degeneration
Authors: Stefanova Nadia , Mitschnigg Monika , Ghorayeb Imad , Diguet Elsa , Geser Felix , Tison Francois , Poewe Werner , Wenning Gregor K. 
Published: July 2004

AbstractPrevious studies in rodent models of neurodegenerative disorders have demonstrated that minocycline exerts neuroprotective effects unrelated to its antimicrobial action. The purpose of the present study was to analyze whether minocycline exhibits neuroprotective activity in a rat model of striatonigral degeneration (SND), the core pathology underlying levodopa‐unresponsive parkinsonism associated with multiple system atrophy (MSA). We observed no significant effect of minocycline on locomotor impairment in double‐lesioned SND rats. Minocycline significantly suppressed astroglial and microglial activation (P < 0.01); however, 3′5′‐monophosphate‐regulated phosphoprotein (DARPP 32) immunohistochemistry revealed no significant differences in striatal lesion volume of minocycline‐treated versus untreated control SND rats. Furthermore, there was no protection of nigral dopaminergic neurons in the double‐lesion model. We conclude that despite its astrocytic and microglial suppression, minocycline failed to attenuate lesion‐induced neuronal damage in the SND rat model. © 2004 Wiley‐Liss, Inc.
α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid receptors signaling complexes in Bergmann glia
Authors: Millán Alejandro , Arias‐Montaño José Antonio , Méndez J. Alfredo , Hernández‐Kelly L. Clara R. , Ortega Arturo 
Published: July 2004

AbstractGlutamate, the major excitatory neurotransmitter, induces a wide array of signals from the membrane to the nucleus regulating gene expression. In Bergmann glia, Ca2+‐permeable α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole‐ propionic acid (AMPA) receptors are involved in the short‐ and long‐term interactions between these cells and the neurons that they surround. After activation, AMPA receptors become tyrosine phosphorylated and by these means form multiprotein signaling complexes. To characterize these events, cultured chick Bergmann glia cells as well as chick cerebellar slices were exposed to glutamate, and, by using a combination of immunoprecipitation assays coupled to Western blot analysis, we identified several signaling proteins that become associated with these receptors. A dose‐ and time‐dependent association among AMPA receptors, the focal adhesion kinase pp125FAK, the phosphatidylinositol‐3 kinase and paxillin was found. These results extend the concept of the transducisome to AMPA receptors and provide a framework in which a plausible control of the cytoskeletal network by glutamate is taking place, most possibly through AMPA receptors. © 2004 Wiley‐Liss, Inc.
Ermittlung von Berechnungskennwerten an Karosseriewerkstoffen – Bericht über ein Gemeinschaftsprojekt der Stahl‐ und Automobilindustrie
Authors: Bleck W. , Engl B. , Frehn A. , Nicklas D. , Steinbeck G. 
Published: July 2004

AbstractIm Rahmen eines gemeinschaftlichen Projektes der Stahl‐ und Automobilindustrie wurden an insgesamt 20 Stählen für Feinblech Kennwerte für die FEM‐Simulation ermittelt. Im Einzelnen handelte es sich um elastische, plastische und zyklische Kennwerte, die über einen Zeitraum von 3 Jahren von unterschiedlichen Prüfstellen erarbeitet wurden. Die untersuchten Stähle unterschieden sich hinsichtlich ihrer Ausgangsgefüge und Werkstoffkonzepte, wobei neben verschiedenen einphasigen ferritischen Stahlsorten auch Mehrphasen‐Stähle wie Dualphasen‐, Complexphasen‐ und TRIP‐Stähle sowie 2 austenitische nicht rostende Stähle zum Einsatz kamen. Die Stähle wurden sowohl im Ausgangszustand als auch in definierten Vorverformungs‐ und Wärmebehandlungszuständen untersucht. Die Vorgaben für die Herstellung dieser Zustände und für die anschließende Prüfung wurden von den Projektpartnern in der sogenannten „Prüf‐ und Dokumentationsrichtlinie”︁ festgelegt, mit deren Hilfe eine standardisierte Kennwertermittlung und Datenaufbereitung für eine von der Automobilindustrie realisierte Werkstoffdatenbank möglich wurde. Den elastischen, plastischen und zyklischen Prüfungen wurde eine Eingangsprüfung vorgeschaltet, in der die Stähle hinsichtlich ihrer Gefügeausbildung, Oberfläche, chemischen Zusammensetzung und mechanischen Eigenschaften im quasistatischen Zugversuch vollständig charakterisiert wurden. Die Ergebnisse der einzelnen Prüfbereiche (plastisch, elastisch, zyklisch) werden in separaten Veröffentlichungen ausführlich vorgestellt. Es hat sich gezeigt, dass Werkstoffgruppen mit nahezu gleicher Verfestigungscharakteristik existieren, so dass eine rechnerische Vorhersage von Kennwerten und Fließkurven artverwandter Stähle möglich erscheint. Diese Thematik wird in einem am 01. Januar 2003 angelaufenen Nachfolgeprojekt im Mittelpunkt der Untersuchungen stehen.
Increased DNA methylation in the HoxA5 promoter region correlates with decreased expression of the gene during tumor promotion
Authors: Watson Rebecca E. , Curtin Geoffrey M. , Hellmann Gary M. , Doolittle David J. , Goodman Jay I. 
Published: July 2004

AbstractPromoter‐region DNA methylation inhibits transcription. A two‐stage SENCAR (sensitive to mouse carcinogenesis) mouse skin carcinogenicity model was used to examine gene‐specific changes in methylation during skin tumor promotion. Analysis was performed on 7,12‐dimethylbenz[a]anthracene (DMBA)‐initiated skin promoted with 9, 18, 27, or 36 mg cigarette smoke condensate (CSC) for 9 wk, or 27 mg CSC for 9 wk and sacrificed 6 wk afterwards (recovery group). Additionally, tumors arising following promotion with 27 mg CSC for 29 wk were assessed. Gene array analysis identified differentially expressed genes. Expression of HoxA5, a tumor suppressor gene, was decreased following 9 wk of treatment with 27 mg CSC, and returned to control levels during recovery. HoxA5 promoter methylation was measured with the enzymatic regional methylation assay (ERMA). DNA was bisulfite‐modified, PCR‐amplified with primers containing dam sites, incubated with [14C‐methyl] S‐adenosyl‐l‐methionine (SAM) and dam methyltransferase for DNA quantification, then incubated with [3H‐methyl] SAM and SssI methylase to quantify methylation status. Higher 3H/14C ratios indicate increased methylation. The 3H/14C ratios of animals promoted with 27 or 36 mg CSC (48.2 ± 6.9 and 24.2 ± 6.1, respectively) were higher than the control or recovery group ratios (12.3 ± 0.1 and 12.6 ± 0.3, respectively); sequence analysis supported these findings. Increased methylation of p16 or O6 methylguanine methyltranferase (MGMT) was detected in 4/8 (50%) of the tumor samples from mice promoted with 27 mg CSC. These data suggest that increased DNA methylation contributes to the downregulation of HoxA5, and combined with hypermethylation of p16 or MGMT, this might facilitate the clonal expansion of increasingly aberrant cells during promotion. © 2004 Wiley‐Liss, Inc.
Prolonged practice is of scarce benefit in improving motor performance in Parkinson's disease
Authors: Agostino Rocco , Currà Antonio , Soldati Giampiero , Dinapoli Loredana , Chiacchiari Luigi , Modugno Nicola , Pierelli Francesco , Berardelli Alfredo 
Published: July 2004

AbstractMany studies have addressed practice effects in motor sequences in Parkinson's disease (PD). Most studied short‐term practice and showed that treated patients with mild‐to‐moderate disease achieve normal or slightly abnormal improvement. Less attention has focused on practice effects after prolonged training (days), and the results are inconclusive. Here, we studied the kinematic changes induced by prolonged practice in a group of medicated patients with mild‐to‐moderate PD and a healthy control group. We did so by analyzing an internally determined sequential arm movement performed as fast and accurately as possible before and after a 2‐week training period. After 1‐day's practice, movement duration, pause duration, and movement accuracy improved similarly in patients and controls, indicating that patients benefitted normally from short‐term practice. After 1‐week's practice, movement and pause duration improved further in both groups, whereas movement accuracy remained unchanged. After 2‐weeks' practice, healthy controls continued to improve but patients did not, indicating reduced prolonged practice benefit in PD. Because short‐term practice benefit on motor performance is thought to be mediated predominantly by cerebellar activation, whereas long‐term practice benefit relies predominantly on the basal ganglia, we attribute our findings to the underlying basal ganglia dysfunction in PD. Our study may be relevant for planning and executing rehabilitation programs in these patients. © 2004 Movement Disorder Society
Modest increase in plasma homocysteine follows levodopa initiation in Parkinson's disease
Authors: O'Suilleabhain Padraig E. , Bottiglieri Teodoro , Dewey Richard B. , Sharma Shailja , Diaz‐Arrastia Ramon 
Published: July 2004

AbstractLevodopa, typically ingested chronically at high daily doses, is predictably methylated by means of a series of reactions using B vitamins, which convert methionine to homocysteine. Elevated total plasma homocysteine (tHcy), a risk factor for dementia, has been found in PD patients using levodopa. We prospectively measured the effects on plasma tHcy and B vitamins of levodopa initiation, and measured the effects of dose changes and of treatment with dopamine agonists and entacapone. We collected paired plasma samples, at baseline and again after several months treatment, from patients initiating levodopa (n = 30), from patients whose levodopa dose was doubled (n = 15), halved or stopped (n = 14), from patients starting or stopping entacapone (n = 15) and from patients initiating or doubling dopamine agonist monotherapy (n = 16). Vitamin B12, folate, and tHcy concentrations were measured. Baseline tHcy concentration of 8.7 (2.8) μmol/L increased to 10.1 (3.1) μmol/L (P = 0.004) an average of 94 (range 36 to 200) days after initiation of 604 (240 to 1050) mg/day of L‐dopa. Average concentration of vitamin B12 fell from 380 to 291 pmol/ L (P = 0.01). Patients who doubled their daily levodopa dose experienced tHcy elevations from 9.5 to 11.1 μmol/L (P = 0.05). Levodopa reduction, agonist treatment, and entacapone treatment did not have significant effects. Levodopa elevates tHcy and lowers vitamin B12 concentration to modest degrees. The clinical implications, if any, have not yet been determined. © 2004 Movement Disorder Society
Association of the C677T and A1298C polymorphisms of methylenetetrahydrofolate reductase gene in patients with essential tremor in Turkey
Authors: Sazci Ali , Ergul Emel , Bayulkem Kemal 
Published: July 2004

AbstractEssential tremor (ET) is a most common human movement disorder of unknown etiology. Previous reports have shown that the C677T polymorphism of methylenetetrahydrofolate reductase gene has been associated with neurodegenerative disorders. To investigate the role of methylenetetrahydrofolate reductase gene polymorphisms in essential tremor, we analyzed the alleles and genotypes of methylenetetrahydrofolate reductase (MTHFR) C677T and MTHFR A1298C in a total of 158 unrelated essential tremor patients and compared them with those of 246 unrelated healthy control subjects, using a polymerase chain reaction restriction fragment length polymorphism method. The allele frequency of MTHFR 677T was 35.76% in the essential tremor cases and 30.08% in the controls. We obtained statistically significant results for MTHFR677 and also for MTHFR1298. The MTHFR T677T genotype was overrepresented and was statistically significant. The T677T/A1298A and C677C/C1298C compound genotypes were similarly statistically significant. The C677C/A1298A compound genotype provided protection for essential tremor. In conclusion, the MTHFR 677T, 1298C alleles and MTHFR T677T genotype and T677T/A1298A, and C677C/C1298C compound genotypes are genetic risk factors for essential tremor in Turkey. © 2004 Movement Disorder Society
Ropinirole is effective in the treatment of restless legs syndrome. TREAT RLS 2: A 12‐week, double‐blind, randomized, parallel‐group, placebo‐controlled study
Authors: Walters Arthur S. , Ondo William G. , Dreykluft Tilman , Grunstein Ron , Lee Daniel , Sethi Kapil ,   on behalf of the TREAT RLS 2 (Therapy with Ropinirole: Efficacy And Tolerability in RLS 2) Study Group
Published: July 2004

AbstractRestless legs syndrome (RLS) is a neurological condition with significant impact on sleep and quality of life (QoL). This double‐blind, randomized, 12‐week, multinational study compared the efficacy and safety of ropinirole and placebo in RLS. In total, 267 outpatients with moderate‐to‐severe RLS were randomly assigned to ropinirole (0.25–4.0 mg/day) or placebo, 1 to 3 hours before bedtime. The primary endpoint was the change in International Restless Legs Scale (IRLS) score at week 12. Key secondary endpoints were the percentage of patients showing significant improvement on the Clinical Global Impression‐Improvement (CGI‐I) scale at week 12 and changes in IRLS and CGI‐I scale scores at week 1. Other measures included the Medical Outcomes Study sleep scale and Restless Legs Syndrome Quality of Life questionnaire. Improvements were significantly greater for ropinirole than placebo for change in IRLS score at week 12 (−11.2 [SE 0.76] vs. −8.7 [0.75], respectively; adjusted treatment difference −2.5 [95% confidence interval [CI], −4.6, −0.4], P = 0.0197); all key secondary endpoints; sleep and QoL parameters. Adverse events were typical for dopamine agonists; disease augmentation, although not directly assessed, was not reported during treatment. Ropinirole improves symptoms, associated sleep disturbance, and QoL of RLS patients and is generally well tolerated. © 2004 Movement Disorder Society