bluuebunny/crossref_metadata_2025_split huggingface dataset:
On‐line automatic SPE‐CE coupling for the determination of biological markers in urine
Authors: Ruiz‐Jiménez José , Mata‐Granados José M. , Luque de Castro Maria Dolores 
Published: February 2007

AbstractAutomatic SPE has been coupled on‐line to CE by a transfer tube and the replenishment system of the CE instrument. The approach allows the target analytes (viz. creatinine, creatine, xanthine, hypoxanthine, uric acid, p‐aminohippuric acid and ascorbic acid in urine samples) to be removed from the sample matrix, cleaned up, preconcentrated and injected into the capillary. The detection limits range between 0.14 and 4.50 μg/mL, the quantification limits between 0.45 and 15.0 μg/mL, and linear dynamic ranges – which include the reference healthy human values – from the quantification limits to 1332 μg/mL. The precision, expressed as RSD, ranges between 0.38 and 2.22% for repeatability and between 1.79 and 7.61% for within‐laboratory reproducibility. The errors, expressed as RSD for all compounds, range between 0.20 and 6.90%. The time for automatic SPE and that necessary for the individual separation–detection of the target analytes are 13 and 12 min, respectively; the analysis frequency is 5 h−1. The accuracy of the method and potential matrix effects were studied by using spiked samples and recoveries between 96.00 and 103.07 % were obtained. The proposed method was applied to samples from healthy young students.
Assignment of human plasma polypeptides on a nondenaturing 2‐D gel using MALDI‐MS and PMF and comparisons with the results of intact protein mapping
Authors: Manabe Takashi , Jin Ya , Tani Osamu 
Published: February 2007

AbstractHuman plasma proteins were separated by 2‐DE under nondenaturing conditions followed by the assignment of the CBB‐stained spots using MALDI‐MS and PMF, aiming to correlate the information of intact proteins with that of constituent polypeptides. A microgel system was employed to facilitate the analysis. Totally 157 spots on a nondenaturing micro‐2‐DE gel were numbered, the spots were excised, the proteins in the gel pieces were subjected to in‐gel digestion with trypsin followed by polypeptide analysis using MALDI‐MS and PMF. Two PMF algorithms, MASCOT (with Swiss‐Prot database) and ProFound (with NCBInr database) were employed. A total of 153 spots out of the 157 provided significant match (p <0.05) with polypeptides in databases. Eighty spots were assigned to contain multiple (2–4) polypeptides, suggesting (i) noncovalent interaction between proteins/polypeptides, (ii) disulfide bonding of polypeptides, or (iii) overlapping of the protein locations on the gel. The results of polypeptide assignment coincided very well with the results of protein mapping previously reported, in which 33 plasma proteins were identified using blotting‐immunochemical staining (Manabe, T., Takahashi, Y., Higuchi, N., Okuyama, T., Electrophoresis 1985, 6, 462–467). Further, 19 polypeptides in 25 spots were newly assigned. These results demonstrate that the techniques of MALDI‐MS and PMF can be applied for analysis of proteins separated on nondenaturing 2‐DE gels, providing information on their polypeptide structure. The integrated information on proteins and polypeptides would help the comprehensive understanding on the functions of complex protein systems.
Competition between cis, trans and Cyclopropane Fatty Acid Formation and its Impact on Membrane Fluidity
Authors: Loffhagen N. , Härtig C. , Geyer W. , Voyevoda M. , Harms H. 
Published: February 2007

AbstractThe impact of cis, trans and cyclopropane fatty acids on membrane fluidity was investigated using batch‐grown Pseudomonas putida P8 and Comamonas testosteroni ATCC 17454. A major difference observed between the two investigated strains is the absence of the ability to synthesize trans‐unsaturated fatty acids in Comamonas. When grown exponentially at 30 °C, a shift to 35 °C increased the trans/cis ratios of the fatty acids of P. putida P8 from 0 to 0.81 and 0 to 1.07, in lipid extracts and cell hydrolyzates, respectively. After prolonged growth followed by nutrient deprivation for 48 h, both at 30 °C, trans fatty acids were absent, but the cyclo/cis ratios rose from 0.1 to 1.55 in lipid extracts, and from 0.1 to 1.54 in cell hydrolyzates. C. testosteroni ATCC 17454 contained no cyclo fatty acids when harvested in the exponential phase after 6 h, whereas after 72 h cultivation, the cyclo/cis ratios rose to 0.49 and 0.47, in lipid extracts and cell hydrolyzates, respectively. Trans fatty acids were never observed in this strain. Increased cyclo/cis and trans/cis ratios correlated with decreased fluidity measured by the fluorescence anisotropy of 1,6‐diphenyl‐1,3,5‐hexatriene (DPH) intercalated in the bilayers of liposomes and by Fourier Transform Infrared (FTIR) spectroscopy of lipids prepared from the cells. The specific effect of cyclopropane fatty acids on membrane fluidity was much smaller than that of trans fatty acids. FTIR‐measurements of intact cells of P. putida P8 confirmed the high potency of trans fatty acids to decrease the fluidity. In cells with induced cyclopropane fatty acid synthesis, the membranes remained more fluidized, indicating the lower importance of these fatty acids for homeoviscosis.
Erosion and natural revegetation associated with surface land drains in upland peatlands
Authors: Holden Joseph , Gascoign Michelle , Bosanko Nick R. 
Published: February 2007

AbstractOpen cut drains are the most frequently used drainage technique in peatlands and are common throughout the world. Land drains increase the drainage density and promote enhanced coupling of hillslope sediment sources with streams. They may be major sources of fine sediment to peatland stream systems but data on drain sediment production in peatlands are rare. Many drains are now being dammed by humans, yet some revegetate naturally. This paper presents a survey of the erosion and natural revegetation of peat drains related to variables such as slope, drainage area and shading. The paper also provides measured comparison of sediment flux from open drains, drains that have been blocked by peat dams, undisturbed subcatchments, and the catchment outlet. Natural infilling of drains was often found to occur on gentle slopes <4°. Drains on slopes <2° were rarely eroded, while drains on slopes >4° were rarely infilled. Nick‐point retreat at the confluence of drains was often observed. Revegetation of drains was uncommon where drains have been cut or incised into the underlying mineral substrate. Where the drain floor was peat‐based, revegetation was much more common. Revegetation of drain floors was affected by overhanging vegetation, which provided shading. Drain floors with less than 60% shading tended to have a greater vegetation cover than drains with 60–90% shading. However, drains that were almost totally shaded (>90%) had the greatest floor vegetation. The intact drains were found to be major sources of suspended sediment within the survey catchments, with 18·3% of the sediment originating from the unblocked drains which drained 7·3% of the area. The winter quarter of the year was more important than other seasons for producing suspended sediment, even though precipitation totals were not greatest during this period. Drains which had been dammed at intervals along their length using peat blocks had very low sediment yields. Even poorly dammed drains, where water could still flow along the full course of the drain, had 54 times less suspended sediment production than unblocked drains. Copyright © 2007 John Wiley & Sons, Ltd.
Some fine‐grained sedimentation phenomena in caves
Authors: Bull Peter A. 
Published: February 2007

AbstractFine‐grained sedimentation in caves often occurs by the parallel accretion of laminations upon the underlying bedforms. These laminations show remarkable persistence in unit thickness and grain size in a down‐passage direction. A translatory flow mechanism ofdeposition is postulated which results in the rhythmic pulsing of sediment‐laden water into subterranean lakes in response to variations in surface climate. The sediments are pulsed into standing water via multiple inputs, often resulting in coarser sediment being deposited on steeper slopes than on more gentle slopes. The final extension of this sediment input is the complete filling of the cave passage to the roof. The problem of sediment stability on steep slopes remains an unanswered anomaly.
Computer simulation of nearshore bar formation
Authors: Davidson‐Arnott Robin G. D. 
Published: February 2007

AbstractA computer simulation model, developed from a conceptual model of sediment transport patterns associated with nearshore bars, is presented. The model simulates wave shoaling, breaking and reformation along a profile normal to the shore from deep water to the beach and determines rates and directions of sediment transport under wave orbital currents and rip cell circulation. The model successfully generates a barred profile from an initial planar profile and under most conditions achieves a state of dynamic equilibrium with sediment circulating across the bars. Input values for wave height, wave period, offshore slope and tidal range were varied in turn in order to determine their individual effect on the shape of the equilibrium profile formed. Breaker type—spilling or plunging—is incorporated in the model and also appears to be a significant factor in determining the shape of the equilibrium profile.
Field measurements of soil creep
Authors: Finlayson Brian 
Published: February 2007

AbstractAn instrument has been designed to measure soil creep optically with a minimum of site disturbance. The instrument is sufficiently sensitive to detect movement in the soil over periods as short as one month. The results of measurements over a nine month period indicate that movement in the soil occurs in seemingly random directions and that large total movement does not necessarily imply a similarly large downslope movement. It is suggested that measurements of the type reported here are necessary for a satisfactory examination of the process involved in soil creep but that measurements over very long time periods are required for estimates of the rate of downslope transport.
The effect of surface texture on the determination of the surface hardness of rock using the schmidt hammer
Authors: Williams R. B. G. , Robinson D. A. 
Published: February 2007

AbstractThe Schmidt hammer is employed by geomorphologists as a convenient field instrument for measuring the hardness of rock surfaces. Field trials indicate that the readings obtained are a function of not only the hardness of the surfaces but also their texture. Smooth planar surfaces give much higher readings than rough or irregular surfaces. This makes interpretation of the results particularly difficult when the hammer is used to measure the hardness of natural rock surfaces that have been roughened by weathering.
The effect of forestry drainage operations on upland sediment yields: The results of a storm‐based study
Authors: Burt T. P. , Donohoe M. A. , Vann A. R. 
Published: February 2007

AbstractThe effects of pre‐afforestation open ditching on the sediment yield of an upland catchment in the Southern Pennines, England are described. Marked increases in the production of suspended sediment following ploughing caused major pollution of a local reservoir. Sediment supply prior to ditching was limited and easily exhausted, but afterwards remained plentiful, allowing sustained erosion during periods of storm runoff. Large volumes of sediment were carried into the reservoir during the winter of 1980–81. More recently, exhaustion of supplies of loose material in the ditches and revegetation have led to a lower rate of sediment output.
The use of gypsum spheres for identifying water flow routes in soils
Authors: Crabtree R. W. , Trudgill S. T. 
Published: February 2007

AbstractGypsum (plaster of paris) has been cast into spheres and placed in soils; weight loss has been used to identify relative water flow routes. Theoretical considerations and laboratory experimentation show that solutional weight loss of the material used increases with increasing water flow, but is independent of pH above pH 4. Results for gypsum sphere weight loss are presented for soils where moisture conditions have been measured independently using tensiometers. The data suggest that the weight loss method provides a viable time‐integrated demonstration of relative water flow routes.
Relationships among dissolved organic matter, iron, and discharge in a moorland stream
Authors: Grieve Ian C. 
Published: February 2007

AbstractDissolved organic matter (DOM) and iron in a moorland stream were determined at 8‐hour intervals over a 6‐month period to examine relationships with streamflow. Regression of both solutes on discharge were positive and explained 50–70 per cent of the variance in the solute data, but better predictions were obtained in both cases when a covariate reflecting temporal variation in the relationships was introduced (explained variance 80–90 per cent). Variations in the regression of Fe on DOM were also identified, indicating differences in the complexing power of DOM for Fe and possible variations in the chemical composition of the DOM.
Long term remeasurements of micro‐erosion meter rates, Aldabra Atoll, Indian Ocean
Authors: Viles H. A. , Trudgill S. T. 
Published: February 2007

AbstractMicro‐erosion meter sites, installed on Aldabra Atoll, Indian Ocean in 1969 to measure erosion rates in coastal and subaerial sites, were remeasured in 1971 and again in 1982. The orders of magnitude of calculated erosion rates are comparable but the precise figures and patterns differ. For subaerial sites the short term (1969–71) range of 0·11–0·58 mm a−1 compares with a long term (1971–82) range of 0·06–0·75 mm a−1; for coastal sites short term ranges of 0·002–7·5 mm a−1 compare with long term rates of 0·09–2·7 mm a−1. Interpretation and extrapolation of short term data should only be made with caution.
Some observations on suspended sediment dynamics in Storbregrova, Jotunheimen
Authors: Richards Keith 
Published: February 2007

AbstractObservations are reported of the dynamics of suspended sediment transport in the meltstream of Storbreen in the Jotunheimen. Fine sediment is transferred from the subglacial to the proglacial environment during low flow (meltdominated) periods, and then removed from the catchment during high flow (rainfall‐controlled) events. Both diurnal and storm period sediment load‐discharge relationships involve clockwise hysteresis, but separate multivariate rating curves define variations of load with streamflow according to (1) the relative importance of meltwater and rainfall runoff, and (2) changes in the sediment source areas contributing to the stream at different times. Particle size variations in the suspended sediment also reflect varying source area influences.
On Playfair's law of accordant junctions
Authors: Kennedy Barbara A. 
Published: February 2007

AbstractGeomorphologists since Playfair have apparently accepted that fluvial confluences will be morphologically accordant in distinction to the hanging junctions of glaciated troughs, a view reinforced by Gilbert's ‘Law of Declivities’. The issue has been largely ignored despite field instances of discordant fluvial junctions and widespread engineering practice which favours discordant confluences in non‐erodible materials.Six categories of fluvial junctions are defined: accordant, hanging (discordant), barred, impeded, disrupted and disturbed. The study focuses principally on the first two classes and defines discordance purely morphologically in terms of relative depth of incision of the confluent thalwegs. Likely controls of accordance/discordance are identified as flow magnitudes, synchroneity of flow régimes, channel boundary materials and debris calibre.Field investigations in Malawi, France, West Malaysia and New Zealand in small (< 100 km2) basins on a variety of rock types are described. Barred junctions are relatively rare, but complex in character. A high proportion of confluences are distinctly discordant and there is a general continuum from accordant cases. Tectonic control is improbable and the principal cause identified is the degree of difference in channel‐forming discharges, estimated by stream magnitude and channel area. Some evidence for lithologic control is also apparent. It appears that many confluences behave as if the tributary junction is non‐erodible and not in the fashion predicted by the Law of Declivities. It is argued that the observed relation is a necessary result of the general down‐stream changes in hydraulic geometry.Limited comparison with glacial trough confluences reveals a difference in degree, but not in nature, although the relationship between discordance and channel size is affected by cross‐section geometry. A 10‐fold difference in the cross‐sectional areas of channels meeting at a junction produces, on average, a 2·4‐fold difference in mean channel depths for fluvial cases and a 4‐fold difference for glacial troughs.The role of varying flow regimes seems to require attention. Nevertheless, it is maintained that ‘Playfair's Law’ is a misleading description of the morphology of fluvial junctions, which behaves fundamentally in the same fashion as glacial troughs.
Simulation of pebble abrasion on coastal benches by transgressive waves
Authors: Bigelow Gordon E. 
Published: February 2007

AbstractTumbler simulations of abrasion processes affecting rocks on basaltic marine benches have clarified the effects of mass and volume of rock fragments on their rate of wear. Several experiments indicate that rate of basalt wear increases with mass in the interval 1 g to 8 g, but is not related to volume of fragments abraded in seawater.Relatively small quantities of rock flour suspended in the immersant seawater substantially reduced the rate of basalt wear. Basalt and calcareous beachrock responded differently in systems with both rock types tumbling together.Examination of the cuttings from these low‐energy encounters suggests that abrasion on elevated benches along exposed seacoasts reduces virtually all clastic material to particles of silt size or smaller, producing essentially no sand.
A simulation model of blowout development
Authors: Jungerius P. D. 
Published: February 2007

AbstractBlowouts are the main feature of wind erosion in the dunes along the Dutch coast. A number of characteristics, such as their growth against the prevailing wind and the spontaneous stabilization when certain dimensions are reached, are believed to be caused by a prominent quality of the southwest wind, viz. its gustiness. This hypothesis is tested in a two‐dimensional computer model which simulates the effect of wind gusts on a sandy surface along the main axis of the blowout. A number of constraints based on field observations are built into the model. The results closely resemble the longitudinal section of the blowout.
Flow resistance in concentrated overland flow on rough slope surfaces
Authors: Roels J. M. 
Published: February 2007

AbstractField experiments have been done on simulated flows over different rough pre‐rill and rill bed surfaces. The purpose of the experiments was to evaluate the hydraulic roughness properties of these bed surfaces. Conventional equations describing the relation of the resistance coefficient to the Reynolds number for flow in closed conduits or open channels can also be applied to shallow flows provided the boundary values of the Reynolds number, which discriminate between the various flow regimes, are adapted. When the Reynolds number is less than 100 the flow regime is laminar. Above this figure the flow is either transitional or turbulent, depending on the roughness of the bed surface. The degree of turbulence can be deduced from a morphological description of the pre‐rill and rill bed surface roughness.
The output of sediments and solutes from forested and cultivated clayey drainage basins in Luxembourg
Authors: Imeson A. C. , Vis M. 
Published: February 2007

AbstractThe output of material from 11 small drainage basins in the Keuper region of central Luxembourg is considered. Attention is given to differences between forested and cultivated basins. Whilst the output of suspended solids from the cultivated Mosergriecht catchment may be as much as five times higher than from the forested Keiwelsbaach, the solute load is only 50 per cent and the runoff 20 per cent higher. Relationships between dispersed clay in suspension and the water chemistry observed for the forested drainage basins are not present in the cultivated catchments. Water having a milky appearance and containing dispersed clay is of more frequent occurrence in forested basins where subsurface runoff occurs in macropores and cracks in the undisturbed soil.
A scanning electron microscope study of bedrock microfractures in granites under high arctic conditions
Authors: Watts Stephen H. 
Published: February 2007

AbstractSurface specimens obtained from highly‐weathered upland plateau outcrops at three localities in high Arctic Canada have been studied using the scanning electron microscope. Observations are given on factors influencing bedrock surface microfracturing processes. Evidence for the concentration of both salts and organic material in surface cracks which could enhance microfracturing is presented. The importance of lithological parameters including: mineralogy, texture, and structures present in influencing the actual processes of disintegration is reiterated. Under cold, dry high Arctic conditions the combined and apparently inseparable affects of frost action, salt crystallization, and organic activity may have contributed to microfracturing largely responsible for widely scattered examples of highly weathered bedrock terrain.
The role of algae in the stabilization of coastal dune blowouts
Authors: Van Ancker J. A. M. Den , Jungerius P. D. , Mur L. R. 
Published: February 2007

AbstractA number of mechanisms prevent blowouts in the dunes along the Dutch‐coast from growing beyond a certain length. Plants play an important role in the stabilization process. Algae are the first plants to colonize the blowouts. Their filaments are surrounded by mucilaginous sheaths which adhere to the sand grains and increase the resistance of the sand to entrainment by wind. This suggests that artificially induced algal growths might be used in cheap, and ecologically justifiable, stabilization measures.
The granulometrical characteristics of a slowly‐moving dust cloud
Authors: Goossens Dirk 
Published: February 2007

AbstractA torn‐up road offered the opportunity to sample a dust cloud continuously at different heights during a time interval of 51 hours. In particular the granulometrical characteristics of the dust caught were investigated. It appears that if the air layer in the vicinity of a dust cloud is not too turbulent, the cloud will be clearly granulometrically stratified. The coarse material moves chiefly at the bottom of the cloud, whereas the fine material will occur both at the bottom and at the top. The experiment also shows that the higher the dust in the cloud, the worse it is sorted. Above a critical height, however, the degree of sorting increases again.The variation of the mean dust diameter d50, as a function of the height z, can be expressed in a simple semi‐logarithmic equation. The variation of the dust quantity G, as a function of the height z, can also be expressed in a semi‐logarithmic form but the correlation is higher when a power equation is used. The ratio of fine silt to coarse silt seems to vary parabolically with height.One can only speak of an optimal transport height in the case of particles > 16 μm. For finer particles, the turbulence of a normal air stream is usually high enough to carry the particles anywhere in the dust cloud, so that one can no longer speak of an optimal transport height.The granulometrical border between aeolian transport in saltation and aeolian transport in suspension lies, according to the results of the experiment, at a diameter of about 63 μm.