bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of glen canyon dam on colorado river sand deposits used as campsites in grand canyon national park, USA
Authors: Kearsley Lisa H. , Schmidt John C. , Warren Katherine D. 
Published: February 2007

AbstractGlen Canyon Dam, located on the Colorado River 24km upstream from Grand Canyon National Park, has affected downstream alluvial sand deposits which are used as campsites by recreational boaters. Inventories of campsite numbers and sizes conducted in 1973, 1983 and 1991, and comparison of aerial photograph series taken in 1965, 1973, 1984 and 1990 show that there has been a system‐wide decrease in the number and size of campsites. Campsites are unevenly distributed along the river, and availability is regarded as ‘critical’ along reaches comprising 45% of the river, based on interviews with river guides. During the first 10 years of Glen Canyon Dam operations, at least 30% of all campsites decreased in size. During the next 18 years, between 1973 and 1991, 32% of all campsites decreased in size, and campsite capacity decreased by 44%. High annual dam releases in excess of power plant capacity in 1983 caused a net system‐wide increase in the number of campsites, but decreased campsite capacity in two critical reaches. The ‘benefit’ of sand aggradation due to the 1983 high flow was short‐lived, and by 1991 only a few campsites were larger than they had been in 1973. In contrast, other sites, especially in critical reaches, were eroded by the 1983 high flows and have not recovered in size. Options for future dam management must consider the variable response of campsites to high flows in critical and non‐critical reaches and the duration over which ‘beneficial’ high flow effects persist.
Characterization of river channel adjustments in the thames basin, south‐east England
Authors: Downs Peter W. 
Published: February 2007

AbstractThe increasing involvement of fluvial geomorphology in river channel management has highlighted the desirability of being able to predict spatially differentiated river channel adjustment in relation to prevailing drainage basin characteristics. An exploratory analysis, using data derived from geomorphological reconnaissance surveys and maps, was carried out with the aim of characterizing river channel adjustments in four catchments within the Thames basin. As many of the variables are categorical in nature, logistic regression is utilized to generate multivariate equations which relate four styles of adjustment to catchment characteristics describing rock type, gradient, land use and channel management. Using only the variables which are statistically significant provides a goodness of fit of around 50%. Geomorphological interpretations of the characterizations are provided and, in general, indicate the varying balance between areally extensive natural controls and more localized human influences in shaping the individual styles of adjustment. In the studied lowland environment it appears that few channels are capable of recovering their sinuosity after channel management, thus highlighting the importance of conserving currently sinuous channels and the restoration of previously straightened reaches. Low gradient rural channels set on Chalk or clay favour deposition and thus may be targeted for maintenance operations. Erosive enlargement of the cross‐section is promoted where channel straightening takes place in zones of high gradient; an option which should be minimized to reduce further management expenditure.
Channel planform change on the river dee meanders, 1876–1992
Authors: Gurnell A. M. , Downward S. R. , Jones R. 
Published: February 2007

AbstractChannel planform change was investigated along an 18 km section of the River Dee on the Welsh‐English border by overlaying information from historical maps and air photographs. The information on river planform change spans the last 115 years, during which time the river has been subject to increasing flow regulation, which may have affected its planform. The downstream location of the reach provides two additional factors which may have an impact on the nature and rate of planform change through their influence on energy conditions in the reach: a tidal backwater influence on the downstream section of the reach; and a low angle of slope.The reach has shown very small changes in planform over the last 115 years, which have been successfully identified by a geographical information system (GIS)‐based data handling methodology, which not only allows the estimation of a variety of indices of change, but also supports the estimation of the potential errors associated with registering the historical sources to a common base and digitizing the channel boundary locations. The study is successful in identifying channel planform change because it has utilized a GIS‐based as opposed to a manual approach, but it represents the lower limit to which bank movement can be confidently identified in a low‐power river environment from 1:10000 scale sources.The changes identified by the GIS‐based methodology include a decrease in channel mobility in a downstream direction; a predominantly oscillatory movement pattern in locations where channel movement has occurred; and an apparent propagation of a decrease in channel width downstream through the reach during the period since 1949, which is the main period of increasing flow regulation.
Magnitude‐frequency analysis of sediment transport in the lower Mississippi river
Authors: Biedenharn David S. , Thorne Colin R. 
Published: February 2007

AbstractMagnitude‐frequency analysis of gauging station records (1950‐1982) on the Lower Mississippi shows that there is a clearly defined dominant flow of about 30000 m3 /s. This lies within an effective range of channel‐forming flows between 17000 and 40000 m3 /s, which are responsible for transporting a disproportionately large percentage of the sediment load. The 33 year period of record is sufficiently long that the occurrence of an extreme high flow event does not significantly change these results. Hydrographic survey data, long‐profile records and stage‐discharge relationships from calibrated one‐dimensional flow models indicate that the dominant discharge corresponds to ‘bar‐full’ discharge on the Lower Mississippi and that the effective range of flows occurs between the stage that just tops mid‐channel bars and that which significantly overtops the banks. Historical trends in bar growth suggest that bar‐top elevations have generally risen to the dominant flow elevation over the last 30 years. In this trained river, where most of the banks are protected by revetments and the alignment is fixed by groynes and spurs, the mid‐channel bars represent the major, contemporary morphological feature of the alluvial river.
Macrozoobenthos abundance and community composition in three lower Rhine floodplain lakes with varying inundation regimes
Authors: Van Brink F. W. B. Den , Beljaards M. J. , Boots N. C. A. , Van Velde G. Der 
Published: February 2007

AbstractThe relative importance of lake inundation regime, littoral substrate and season for macrozoobenthos abundance and community composition was studied in three Lower Rhine floodplain lakes situated along a flood duration gradient. In each lake the macrozoobenthos density, biomass and community composition were determined monthly over one year in two contrasting littoral substrates (sandy‐mineral sediments and clayey‐organic sediments). The influence of the lake inundation regime on the macrozoobenthos abundance was tested against those of littoral substrate and season with a three‐way analysis of variance (ANOVA). Between‐lake variation in macrozoobenthos abundance was clear for Bivalvia, Ephemeroptera, Heteroptera and Trichoptera. Bivalvia (Pisidium sp.) were most abundant in the frequently flooded lake, Heteroptera [Micronecta sp., Sigarafalleni (Fieber), S. striata (L.)] in the rarely flooded lake and Trichoptera [Mystacides longicornis (L.), M. nigra (L.)] and Ephemeroptera [Caenis horaria (L.), C. luctuosa Burmeister] in the isolated, non‐flooded lake, suggesting an impact of inundation regime on the abundance of these dominant taxa in Lower Rhine floodplain lakes. In each lake the annual average abundance of macrozoobenthos was dominated by Gastropoda [Bithynia tentaculata (L.), Potamopyrgus antipodarum (Gray), Valvata piscinalis (Müller)].Between‐lake variations in the relative densities of macrozoobenthos functional feeding groups suggests an impact of the inundation regime on the macrozoobenthos communities via the availability of nutritional resources. Relative densities of filter‐feeders (e.g. Pisidium sp.) were highest in the frequently flooded lake with its high phytoplankton biomass and poorly developed vegetation. Shredders (e.g. Mystacides sp.) were most numerous in the non‐flooded lake with its well developed aquatic vegetation and low phytoplankton biomass.Within‐lake variations in macrozoobenthos abundance could be attributed to littorai substrate and season. The importance of substrate on macrozoobenthos abundance was most clear for Oligochaeta and Trichoptera. The importance of season on macrozoobenthos abundance was clear for the total macrozoobenthos and for all taxonomic groups, except Oligochaeta. Correlations between the total macrozoobenthos abundance and seasonally fluctuating parameters, i.e. flood pulse duration, water level, water temperature and vegetational coverage in the lakes, suggest that hydrological parameters were most important in the frequently flooded lake, whereas vegetational coverage and water temperature were most important in the isolated, non‐flooded lake.
Low flows and recovery of macroinvertebrates in a small regulated chalk stream
Authors: Wood P. J. , Petts G. E. 
Published: February 2007

AbstractThe ecological effects of, and subsequent recovery from, a protracted drought exacerbated by groundwater abstractions on a small English chalk stream are described. Preliminary data from 15 sites showed significant physical and biotic changes between two surveys (in 1992 and 1993) and between ‘upland’ and ‘lowland’ sectors. At the end of the drought (1992) the macroinvertebrate community was severely reduced in the upland sector—with low abundances and species richness—but recovery was dramatic with the return of normal flows. In contrast, relatively little change was observed in the lowland sector. The observed faunal differences are discussed in relation to information on the impact of previous droughts and recovery rates.
NiFe Nanoparticles: A Soft Magnetic Material?
Authors: Margeat Olivier , Ciuculescu Diana , Lecante Pierre , Respaud Marc , Amiens Catherine , Chaudret Bruno 
Published: February 2007

AbstractPolytetrahedral NiFe nanoparticles with diameters of (2.8±0.3) nm have been obtained by hydrogenation of Ni[(COD)2] (COD=1,5‐cyclooctadiene) and Fe[{N(SiMe3)2}2] at 150 °C using stearic acid and hexadecylamine as stabilizing ligands. The nanoparticles are superparamagnetic at room temperature and display a blocking temperature of 17.6 K. Their anisotropy (2.7×105J m−3) is determined to be more than two orders of magnitude higher than that of the bulk NiFe alloy (103J m−3) and is close to that determined for Fe nanoparticles of the same size. Still, they display a magnetization of (1.69±0.05) μB per metallic atom, identical to that of the bulk NiFe alloy. Combining the results from X‐ray absorption and Mössbauer studies, we evidence a progressive enrichment in iron atoms from the core to the surface of the nanoparticles. These results are discussed in relation to both size and chemical effects. They show the main role played by the enriched Fe surface on the magnetic properties and address the feasibility of soft magnetic materials at the nanoscale.
Effect of Osmotic Pressure on Starch: New Method of Physical Modification of Starch
Authors: Pukkahuta Chirdchan , Shobsngob Sujin , Varavinit Saiyavit 
Published: February 2007

AbstractA new method of physical modification of starch in the presence of high concentrated salt solution is presented, called “Osmotic Pressure Treatment” (OPT). OPT was introduced in order to produce the same physically modified products as obtained by conventional heat‐moisture treatment (HMT) of starch. Potato starch was selected for the comparative study of the two methods. For the OPT method, potato starch was suspended in a saturated solution of sodium sulfate and heated in an autoclave at 105°C and 120°C ,which corresponded to the calculated osmotic pressures of 328 and 341 atm (332 and 345 bar, respectively) (assuming sodium sulfate dissociates completely) for 15, 30 and 60 min, respectively. For the HMT method, starch with 20% moisture content was placed in a Duran bottle, then the same heat treatment method in the autoclave was applied. Light and scanning electron microscopy (SEM) showed that OPT of starch changed the shape of the starch granules to a folded structure, while the starches remained unchanged after HMT. The RVA viscogram for the OPT starch exhibited a decrease in the peak viscosity without a breakdown and an increase of the pasting temperature when increasing the temperature and time, which was in an agreement with the viscosity patterns for the HMT starches. X‐ray diffraction patterns were altered from B to A+B for the HMT and from B to A type for the OPT starch when treated at 120°C. After OPT, the gelatinization temperatures (To, Tp, and Tc) of the starch increased significantly with increasing temperature and time, whereas only the Tc of starch increases after HMT. The biphasic broadening of the peaks (high Tc‐To) can be explained by an inhomogeneous heat transfer during HMT. Narrow peaks in the DSC curve can be an indication for a better homogeneity of the OPT samples. However, both methods provide a similar decrease in the gelatinization enthalpy (ΔH). The amylose‐amylopectin ratio calculated from the HPSEC patterns was strongly increased for HMT starches at 105°C for 60 min and 120°C for 30 min and decreased after treatment at 120°C for 60 min. For OPT starches the ratio was strongly increased at 120°C for 15 min and decreased after prolong heating. The OPT provides a uniform heat distribution in the starch suspension. This allows the modified starch to be produced on a larger scale.
Synthesis and Optimization of the Reaction Conditions of Starch Sulfates in Aqueous Solution
Authors: Cui Dapeng , Liu Mingzhu , Liang Rui , Bi Yinghui 
Published: February 2007

AbstractStarch sulfate was prepared by chemical modification of potato starch with trisulfonated sodium amine (N(SO3Na)3), which was synthesized by reaction of sodium bisulfite and sodium nitrite in aqueous solution. The factors that could affect the degree of substitution (DS) of potato starch were investigated in detail, which included reaction temperature and time of preparing the sulfating agent, reaction temperature and time of synthesizing the starch sulfate, dosage of sulfating agent and potato starch, pH of sulfation reaction medium, and the ratio of liquid volume to starch mass. A starch sulfate with DS of 2.14 was obtained under optimal conditions. FTIR spectra showed the characteristic absorptions of sulfate ester bonds at 1236 cm−1 and 821 cm−1.
One‐Step Extraction and Concentration of Polyunsaturated Fatty Acids from Fish Liver
Authors: Guil‐Guerrero J. L. , López‐Martínez J. C. , Rincón‐Cervera M. A. , Campra‐Madrid P. 
Published: February 2007

AbstractThe fatty acids (FA) eicosapentaenoic acid (20:5ω‐3; EPA) and docosahexaenoic acid (22:6ω‐3; DHA), which have several health benefits, have been concentrated from mako shark liver (Isurus oxyrinchus). The process was carried out in one single step, in which fish liver oil was simultaneously extracted, saponified and concentrated. Additionally, the polyunsaturated fatty acids (PUFA) concentrate was winterized to crystallize the remaining saturated FA, resulting in a further increase in the concentration of DHA and EPA. Two variables, temperature and water concentration in the saponification mixture, were optimized to increase the concentration of ω‐3 PUFA. Best results were obtained at 12 °C and 0% water content in the mixture, obtaining 17.8% purity and 77.6% yield of EPA; DHA purity and yield were 33.3 and 82.2%, respectively.
Genetic polymorphisms of CYP2C9 and CYP2C19 are not related to drug‐induced idiosyncratic liver injury (DILI)
Authors: Pachkoria K , Lucena M I , Ruiz‐Cabello F , Crespo E , Cabello M R , Andrade R J ,   on behalf of the Spanish Group for the Study of Drug‐Induced Liver Disease (Grupo de Estudio para las Hepatopatías Asociadas a Medicamentos (GEHAM)
Published: February 2007

Background and purpose:The general view on the pathogenesis of drug‐induced idiosyncratic liver injury (DILI) is that parent compounds are rendered hepatotoxic by metabolism, mainly by cytochrome (CYP) 450, although other metabolic pathways can contribute. Anecdotal reports suggest a role of CYP 450 polymorphisms in DILI. We aimed to assess in a series of Spanish DILI patients the prevalence of important allelic variants of CYP2C9 and CYP2C19, known to be involved in the metabolism of several hepatotoxic drugs.Experimental approach:Genotyping of CYP2C9 (*2, *3) and CYP2C19 (*2 and *3), was carried out in a total of 28 and 32 patients with a well established diagnosis of DILI. CYP2C9 and CYP2C19 variants were analysed in genomic DNA by means of PCR‐FRET and compared with previous findings in other Caucasian populations.Key results:CYP2C9 and CYP2C19 allele and genotype frequencies were in agreement with Hardy‐Weinberg equilibrium. Fourteen patients (50%) were heterozygous and 1(4%) found to be compound heterozygous for the CYP2C9 allele. Seven (22%) were found to carry one and 1(3%) carried two CYP2C19 mutated alleles. No patients were homozygous for *3 allele. The distribution of both CYP2C9 and CYP2C19 allelic variants in DILI patients were similar to those in other Caucasian populations. Patients with variant and those with wild‐type alleles did not differ in regard to clinical presentation of DILI, type of injury and outcome.Conclusions and Implications:We find no evidence to support CYP2C9 and CYP2C19 genetic polymorphisms as predictable potential risk factors for DILI.British Journal of Pharmacology (2007) 150, 808–815. doi:10.1038/sj.bjp.0707122
Phosphorylation of sodium channels mediated by protein kinase‐C modulates inhibition by topiramate of tetrodotoxin‐sensitive transient sodium current
Authors: Curia G , Aracri P , Colombo E , Scalmani P , Mantegazza M , Avanzini G , Franceschetti S 
Published: February 2007

Background and purpose:Topiramate is a novel anticonvulsant known to modulate the activity of several ligand‐ and voltage‐gated ion channels in neurons. The mechanism of action of topiramate, at a molecular level, is still unclear, but the phosphorylation state of the channel/receptor seems to be a factor that is able to influence its activity. We investigated the consequences of phosphorylation of the sodium channel on the effect of topiramate on tetrodotoxin (TTX)‐sensitive transient Na+current (INaT).Experimental approach:INaTwas recorded in dissociated neurons of rat sensorimotor cortex using whole‐cell patch‐clamp configuration.Key results:We found that topiramate (100 μM) significantly shifted the steady‐state INaTinactivation curve in a hyperpolarized direction. In neurons pre‐treated with a PKC‐activator, 1‐oleoyl‐2‐acetyl‐sn‐glycerol (OAG; 2 μM), the net effect of topiramate on steady‐state INaTinactivation was significantly decreased. In addition, OAG also slightly shifted the INaTactivation curve in a hyperpolarized direction, while perfusion with topiramate had no effect on the parameters of INaTactivation.Conclusions and Implications:These data show that PKC‐activation can modulate the effect of topiramate on INaT. This suggests that channel phosphorylation in physiological or pathological conditions (such as epiliepsy), can alter the action of topiramate on sodium currents.British Journal of Pharmacology(2007)150, 792–797. doi:10.1038/sj.bjp.0707144
Rotational Analysis of two Mutually Interacting Electronic States of1Π Character in Th0
Authors: A von Bornstedt  , G Edvinsson  
Published: February 2007

Two new electronic states of1Π character have been found for the Th0 molecule. Rotational analysis shows that there are homogeneous perturbations between the two states, and these perturbations have been analysed by computer methods. Some derived molecular constants are given below.StateT0BecBedΔG1/2M21 734.320.3258570.325754850.87K22 635.650.3186360.318642795.5
NetPhosYeast: prediction of protein phosphorylation sites in yeast
Authors: Ingrell Christian R. , Miller Martin L. , Jensen Ole N. , Blom Nikolaj 
Published: February 2007

AbstractSummary: We here present a neural network-based method for the prediction of protein phosphorylation sites in yeast—an important model organism for basic research. Existing protein phosphorylation site predictors are primarily based on mammalian data and show reduced sensitivity on yeast phosphorylation sites compared to those in humans, suggesting the need for an yeast-specific phosphorylation site predictor. NetPhosYeast achieves a correlation coefficient close to 0.75 with a sensitivity of 0.84 and specificity of 0.90 and outperforms existing predictors in the identification of phosphorylation sites in yeast.Availability: The NetPhosYeast prediction service is available as a public web server at http://www.cbs.dtu.dk/services/NetPhosYeast/Contact: nikob@cbs.dtu.dk
Interleukin‐4 induces human hepatocyte apoptosis through a Fas‐independent pathway
Authors: Aoudjehane Lynda , Podevin Philippe , Scatton Olivier , Jaffray Patrick , Dusanter-Fourt Isabelle , Feldmann Gérard , Massault Pierre-Philippe , Grira Lilia , Bringuier Annie , Dousset Bertrand , Chouzenoux Sandrine , Soubrane Olivier , Calmus Yvon , Conti Filomena 
Published: February 2007

ABSTRACTIL‐4 is overexpressed in liver grafts during severe recurrent hepatitis C and rejection. Hepatocyte apoptosis is involved in both these phenomena. We therefore examined the proapoptotic effect of IL‐4 on HepG2 cells and human hepatocytes in vitro, together with the underlying mechanisms. We first measured IL‐4 receptor expression, STAT6 activation by IL‐4, and STAT6 inhibition by an anti‐IL‐4 antibody or by STAT6 siRNA transfection. We then focused on the pathways involved in IL‐4‐mediated apoptosis and the role of STAT6 activation in apoptosis initiation. The IL‐4 receptor was expressed on both cell types, and STAT6 was activated by IL‐4. Both anti‐IL‐4 and STAT‐6 siRNA inhibited this activation. IL‐4 induced apoptosis of both HepG2 cells (P= 0.008 vs. untreated control) and human hepatocytes (P<0.001 vs. untreated control). IL‐4 reduced the mitochondrial membrane potential, activated Bid and Bax, and augmented caspase 3, 8, and 9 activity. STAT6 blockade inhibited IL‐4‐induced apoptosis. Expression of Fas and Fas ligand was unaffected when HepG2 cells and hepatocytes were cultured with IL‐4, and Fas/FasL pathway blockade failed to inhibit IL‐4‐induced apoptosis. These results show that IL‐4 induces apoptosis of human hepatocytes through IL‐4 receptor binding, STAT6 activation, decreased mitochondrial membrane potential, and increased caspase activation, independently of the Fas pathway. IL‐4 might thus contribute to the progression of severe liver graft damage.—Aoudjehane, L., Podevin, P., Scatton, O., Jaffray, P., Dusanter‐Fourt, I., Feldmann, G., Massault, P. P., Grira, L., Bringuier, A., Dousset, B., Chouzenoux, S., Soubrane, O., Calmus, Y., Conti, F. Interleukin‐4 induces human hepatocyte apoptosis through a Fas‐independent pathway. FASEB J. 21, 1433–1444 (2007)