bluuebunny/crossref_metadata_2025_split huggingface dataset:
Supercritical fluid extraction and quantification of aflatoxins in Zizyphi Fructus by liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometry
Authors: Liau Bing‐Chung , Jong Ting‐Ting , Lee Maw‐Rong , Chang Chieh‐Ming J. 
Published: February 2007

AbstractAn integrated method combining supercritical fluid extraction (SFE) with liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometry (LC/APCI‐MS/MS) was developed and successfully applied to quantify aflatoxins (AFs) in Zizyphi Fructus (fruits of Zizyphus jujube), a traditional Chinese medicine. To minimize the potential interferences caused by the complex matrix in Zizyphi Fructus, a SFE pretreatment was performed. In addition, electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) spectra were also compared. The results showed that the calibration curves of AFB1, AFB2, AFG1, and AFG2 were all linear over the range of concentration from 1 to 50 ng/g, the squared correlation coefficients (r2) were over 0.995, and the detection limits of the method were between 0.17 and 0.32 ng/g. It showed high recovery and good precision in quantitating AFs in Zizyphi Fructus without further clean‐up. Further, fragmentation pathways of protonated AFs in APCI‐MS/MS were clearly proposed which could predict the existence of AFB or AFG series. To test the empirical validity of the proposed methodology in this paper, eight random samples of Zizyphi Fructus collected from supermarkets and traditional Chinese medicine stores in different geographical areas of Taiwan were analyzed. The results indicated that low levels of AFs were detected in only one of them. Copyright © 2007 John Wiley & Sons, Ltd.
A potential pitfall in 18O‐based N‐linked glycosylation site mapping
Authors: Angel Peggi M. , Lim Jae‐Min , Wells Lance , Bergmann Carl , Orlando Ron 
Published: February 2007

AbstractA common procedure for identifying N‐linked glycosylation sites involves tryptic digestion of the glycoprotein, followed by the conversion of glycosylated asparagine residues into 18O‐labeled aspartic acids by PNGase F digestion in 18O water. The 3 Da mass tag created by this process is readily observable by liquid chromatography/tandem mass spectrometry (LC/MS/MS) analysis, and is often used to identify the sites of N‐linked glycosylation. While using this procedure, we noticed that 60% of the asparagines identified as being glycosylated were not part of the consensus sequence required for N‐linked glycosylation, and thus were not biologically possible. Investigation into the source of this unacceptably high false positive rate demonstrated that even after reversed‐phase cleanup and heat denaturation, the trypsin used for proteolysis was still active and led to the incorporation of 18O into the C‐termini of the peptides during the deglycosylation step. The resulting mass shift accounted for most of the false positive sites, as the database search algorithm confused it with an 18O‐labeled Asp residue near the C‐terminus of a peptide. This problem can be overcome by eliminating trypsin from the solution prior to performing the deglycosylation process, by resuspending the peptides in natural abundance water following deglycosylation, or by allowing 18O incorporation into the C‐terminus as a variable modification during the database search. These methods have been demonstrated on a model protein, and are applicable to the analyses of glycoproteins that are digested with trypsin or another serine protease prior to enzymatic release of the carbohydrate side chains. This study should alert investigators in the field to this potential and unexpected pitfall and provide strategies to overcome this phenomenon. Copyright © 2007 John Wiley & Sons, Ltd.
Use of an integrated MS – multiplexed MS/MS data acquisition strategy for high‐coverage peptide mapping studies
Authors: Chakraborty Asish B. , Berger Scott J. , Gebler John C. 
Published: February 2007

AbstractLiquid chromatography/mass spectrometry (LC/MS) peptide maps have become a basic tool for characterizing proteins of biological and pharmaceutical interest. The ability to generate reproducible maps with high protein sequence coverage is a central goal of methods development. We have applied a recently developed analytical approach (termed LC/MSE) to LC/MS peptide mapping. Using the LC/MSE approach, the mass detector alternates between a low‐energy scanning mode (MS) for accurate mass peptide precursor identification, and an elevated‐energy mode (MSE) for generation of accurate mass multiplex peptide fragmentation data. In this paper, we evaluate this analytical approach against a tryptic digest of yeast enolase. From the low‐energy data, high peptide map coverage (98% of sequence from peptides >3 amino acids) was reproducibly obtained. The MS signal for essentially equimolar peptides varied over 2 orders of magnitude in intensity, and peptide intensities could be precisely and reproducibly measured. Using the temporal constraint that MSE peptide fragment ions exhibit chromatographic profiles that parallel the precursor ions that generated them, we were able to produce accurate mass time‐resolved MS/MS information for all enolase peptides with sufficient abundance to produce a detectable fragment ion. Copyright © 2007 John Wiley & Sons, Ltd.
Analysis of bone minerals by time‐of‐flight secondary ion mass spectrometry: a comparative study using monoatomic and cluster ions sources
Authors: Malmberg Per , Bexell Ulf , Eriksson Cecilia , Nygren Håkan , Richter Katrin 
Published: February 2007

AbstractTime‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) is an important tool for the analysis of bone minerals at implant surfaces. Most studies have been performed with monoatomic primary ion sources such as Ga+ with poor secondary molecular ion production efficiency and only elemental distributions and minor fragments of bone minerals have been reported. By using cluster ion sources, such as Au and Bi, identification of larger hydroxyapatite species at m/z 485, 541, 597 and 653, identified as Ca5P3O12, Ca6P3O13, Ca7P3O14 and Ca8P3O15, respectively, became possible. The ions appear to be fragments of the hydroxyapatite unit cell Ca10(PO4)6(OH)2. Each ion in the series is separated by 55.9 m/z units, corresponding to CaO, and this separation might reflect the columnar nature of the unit cell. Copyright © 2007 John Wiley & Sons, Ltd.
Coupled N, C and S stable isotope measurements using a dual‐column gas chromatography system
Authors: Fry Brian 
Published: February 2007

AbstractMany laboratories routinely analyze plant, animal and soil samples with elemental analyzers coupled to isotope ratio mass spectrometers, obtaining rapid results for nitrogen (%N, δ15N) and carbon (%C, δ13C) from the same sample. The coupled N and C measurements are possible because of a gas chromatography (GC) separation of N2 and CO2 gases produced in elemental analysis. Adding a second GC column allows additional measurement of sulfur (%S, δ34S) from the same sample, so that combined N, C and S information is obtained routinely. Samples are 1–15 mg, and replicates generally differ by less than 0.1‰ for δ15N, δ13C or δ34S. An example application shows that the N, C, and S measurement system allows a three‐dimensional view of element dynamics in estuarine systems that are undergoing pollution inputs from upstream watersheds. Extension of these GC principles should allow coupled H, C, N, and S isotope measurements in future work. Copyright © 2007 John Wiley & Sons, Ltd.
Quantitative analysis of 23‐hydroxybetulinic acid, a novel anticancer substance, in the cellular environment of a human colon adenocarcinoma cell line for cellular pharmacokinetic studies
Authors: Zheng Yuanting , Wang Guangji , Wu Xiaolan , Sun Jianguo , Li Xiaoyu , Gu Yi , Lv Hua , Liang Yan , Yan Bei , Ye Wencai 
Published: February 2007

AbstractIn order to study the cellular distribution and kinetics of a new anticancer substance, 23‐hydroxybetulinic acid, a simple, reproductive and sensitive high‐performance liquid chromatography/mass spectrometric (HPLC/MS) method was developed to quantify its trace concentration in cell suspension and cell culture medium. This method involved a liquid‐liquid extraction with diethyl ether and a subsequent analysis performed on a Shimadzu LCMS 2010A system which contained an electrospray ionization interface. Separation was achieved by HPLC on a Zorbax Extend‐C18 column with gradient elution using a mix of acetonitrile and water containing triethylamine and acetate‐triethylamine as the mobile phase. A total analytical run was achieved within 6.5 min and the calibration curve was linear over a wide concentration range of 1.0–1000.0 nM for both cell suspension and culture medium. Intra‐ and inter‐batch accuracy and precision were acceptable for both matrices. The described assay method was successfully applied to cellular pharmacokinetic studies in a human colon adenocarcinoma cell line (Caco‐2) and its application of measuring the cellular concentrations of 23‐hydroxybetunilic acid could be extended to different cultured cell lines. Copyright © 2007 John Wiley & Sons, Ltd.
The distribution and management of channelized streams in Denmark
Authors: Brookes Andrew 
Published: February 2007

AbstractThe Danish Watercourse Law of 1982 states that major river works and maintenance procedures must be planned and undertaken with regard to water quality and the physical form of the river channel. Fluvial geomorphology is an essential component of alternative procedures of river management which work with nature rather than against it. A survey of Danish stream channels has been produced by collating data obtained from maps, field surveys and engineering documents. This indicates that 97.8 per cent of Danish watercourses have been artificially straightened and that only 2.2 per cent (880 km) have natural morphological characteristics. The density of channel works is 300 times greater than in the U.S.A. and 15 times greater than in England and Wales. It is suggested that since there are only a few naturally sinuous channels in Denmark these should be given special consideration with regard to stream management practices. Measurements undertaken at approximately 300 sites in Denmark indicate five major processes of adjustment within straightened reaches. These adjustments include degradation of the channel bed with associated bank slumping, armouring of the bed, the development of a sinuous thalweg by the deposition of sediment at low gradients, and restoration of meanders. Channel stability is related to specific stream power and the results may be useful in predicting potential adjustments following channel straightening. Deposition in natural reaches below straightened channels often obliterates pool and riffle sequences but several channel adjustments may provide a greater variability of physical habitats than the initial uniform straightened channel; their significance for the biology of the watercourse is best considered before traditional management practices are carried out to control the adjustment.
A method for applied ecological studies of fluvial hydrosystems
Authors: Amoros C. , Roux A. L. , Reygrobellet J. L. , Bravard J. P. , Pautou G. 
Published: February 2007

AbstractThe hydrosystem of the Rhǒne River, France, is considered in 3 dimensions: the upstream‐downstream progression, the transversal dimension (main stream, side‐arms, marshes, flood plain and their interconnections), and the vertical dimension (relationships between epigean and ground waters). Emphasis is placed on the temporal dimension, which considers changes in the river's dynamics, and on the development of its ecosystems over several centuries.Analyses were performed on different spatial scales; the definitions of functional sectors, functional sets and functional units are based on a combination of geomorphic patterns, fluvial dynamics and ecological processes. Synchronic and diachronic analyses were carried out using functional describers (granulometry and organic content of sediments, floral and faunal communities).These studies deal mainly with the distrubed hydrosystems of regulated rivers. The changes of the ecological successions are focused on after reference to natural models and the reconstitution of ancient human disturbances. Predictive scenarios are proposed to promote ecological management of the alluvial plains in the event of hydroelectric development.
The influence of kielder water on trichopteran (Caddisfly) populations in the river North Tyne (Northern England)
Authors: Boon P. J. 
Published: February 2007

AbstractImpounding the North Tyne has reduced the frequency of high peak flows, eliminated periods of extremely low flow and modified the temperature regime downstream from the Kielder dam. This paper compares the results of a recent survey of North Tyne trichopteran populations (Hydropsychidae, Rhyacophilidae, and Polycentropodidae) with those from previously published work in order to assess the impact of river regulation. Benthic samples were collected monthly upstream and downstream from the reservoir. Although nine out of the ten species found previously were also collected in the post‐impoundment survey, species diversity was reduced downstream from the dam. This was mainly the result of disproportionate increases in Hydropsyche siltalai population densities which were up to 9.6 times greater than before; flow regulation and its effect on substrate stability may be largely responsible for this. Rhyacophila dorsalis also increased in abundance downstream probably in response to the altered flow regime. In contrast Hydropsyche pellucidula constituted a smaller proportion in downstream samples with population densities in places only a fifth of pre‐impoundment levels. The differential effect of regulation on these two hydropsychid species may be explained by their different flow velocity preferences. Upstream from the reservoir, standing crops were frequently lower than before possibly due to the disruption of colonization cycles. Growth rates of H. siltalai, H. pellucidula, and R. dorsalis below the dam were accelerated at certain times of the year and retarded at others, apparently correlated with the winter‐warm, summer‐cool discharges from the reservoir. Since this study was completed Kielder Water has now begun generating hydroelectricity, and the flow regime downstream has consequently changed to one of regular, daily fluctuations. It is suggested that any adverse effects of this on the benthic community are likely to be offset by the continued benefit of eliminating flash floods with high peak flows.
Effects of transferring glacier‐fed water to a clear‐water mountain river on the production and food organisms of brown trout (Salmo trutta L.) in Southern Norway
Authors: Hesthagen Trygve , Fjellheim Arne 
Published: February 2007

AbstractThe effects of transferring glacier‐fed water to a clear‐water river on production and food organisms of brown trout (Salmo trutta L.) were investigated in a mountain river, in southern Norway. Production in unregulated fluvial habitat was 271.5 g 100 m−2 yr−1 compared with 103.1 g 100 m−2 yr−1 in a glacier‐fed reach of the river. This difference was due to low fish density and recruitment rate. The growth rate, at least for younger fish (2+ to 4+ age groups), was significantly higher in the regulated reach of the river. The main difference in food composition was the low abundance of crustaceans Eurycercus lamellatus and Gammarus lacustris in the regulated reach. Trichopterans were the main diet component in both sites.
Response of the aquatic macroinvertebrate communities to dam construction on the Thomson river, Southeastern Australia
Authors: Doeg T. J. , Davey G. W. , Blyth J. D. 
Published: February 2007

AbstractAquatic macroinvertebrates were sampled above and below the site of the Thomson Dam, Victoria, Australia, over a two‐year period during dam construction. Total number of species and the number of species and individuals per sample were all lower for 33 km below the dam site, compared with sites upstream.Ordination analysis showed that the major differences between the study sites were related to longitudinal position in the river. The second ordination axis could be related to seasonal changes in the fauna. Variations in the pattern of axis 2 scores at sites downstream of the damsite suggested continuing changes in the community at these sites during the study, possibly due to increases in the density of species favoured by sediment deposition (e.g. Cheumatopsyche sp. 2: Trichoptera, Hydropsychidae).Classification analysis separated the faunal communities at sites above and below the construction zone. Inverse classifications indicated species with disjunct distributions on either side of the dam site. By comparison with preconstruction data and surrounding undisturbed rivers, species likely to have been disadvantaged by increased sedimentation were identified. These included Atalophlebioides sp. 1 (Ephemeroptera, Leptophlebiidae), Stenoperla australis (Plecoptera, Eustheniidae) and Scirtidae (Coleoptera).
Observed and predicted occurrence of blackflies (diptera: Simuliidae) at fifty reservoir outlets in Britain
Authors: Bass J. A. B. , Armitage P. D. 
Published: February 2007

AbstractThe blackflies present at 50 reservoir outlets throughout mainland Britain were recorded. The observed occurrence of simuliid taxa at sites below upland and lowland reservoirs was compared with the predicted occurrence using predictive equations based on environmental variables.Below the upland reservoirs five simuliid taxa which were predicted to occur were not recorded. Of these S. reptans gp showed the widest discrepancy between predicted and observed occurrences. Four taxa were recorded at significantly fewer sites than predicted and a further four were present at a small number of sites, not differing greatly from the predicted frequency. A similar pattern was observed at the lowland reservoir outlets but S. noelleri, a species frequently associated with lake outlets, was present at more sites than predicted.The influence of a reservoir's presence on the simuliid community is discussed in relation to the known requirements of the species occurring and those predicted to occur.
Effects of stream and lake regulation on reproductive success of kokanee in the flathead river system, Montana, U.S.A
Authors: Fraley John , Decker‐Hess Janet 
Published: February 2007

AbstractKokanee (Oncorhynchus nerka) provided an important recreational fishery in the Flathead River‐Lake system (Columbia River Basin, U.S.A.‐Canada) until the late 1970s when populations declined dramatically. The declines coincided with peaking river discharge from Hungry Horse Dam during the autumn spawning period and an increase in the duration of lake drawdown caused by the operation of Kerr Dam on the outlet of Flathead Lake. Redds of both river and lakeshore spawners were, therefore, dewatered in winter, causing high freezing and desiccation mortality of eggs during the incubation period. It appeared that growth rates of kokanee were density dependent. Female kokanee from strong year classes (i.e., those produced during years of favourable water levels and flow conditions during the incubation period) were smaller than those from weak year classes when unfavourable conditions for incubation prevailed. A highly significant relationship (r2 = 0.929, p < 0.001) was demonstrated between female kokanee spawner length, river gauge heights, and lake levels during years which produced each year class. The close fit of the relationship was further validated by the strong correlation (r = 0.964) between actual kokanee lengths and predicted lengths. Other factors which could have influenced kokanee year class strength include hatchery plants of kokanee fry, harvest of kokanee by anglers, variations in the carrying capacity of Flathead Lake, and natural fluctuations in egg and fry mortality.
The first five months of the supa reservoir, river Kali, India
Authors: Birasal N. R. , Nadkarni V. B. , Gouder B. Y. M. 
Published: February 2007

AbstractThe Supa Reservoir began to fill in 1984, as part of a hydroelectric power scheme on the Kali River in south‐central India. There were significant increases in electrical conductivity and concentrations of chloride, phosphate, iron and manganese in the impounded water during the filling phase. There were also decreases in pH, turbidity, and dissolved oxygen, accompanied by the evolution of hydrogen sulphide. Nutrients leached from the flooded soil and from decomposition of submerged vegetation contributed to blooms of the cyanobacterium Microcystis aeruginosa. The new reservoir has potential for fisheries based on two major carp species, the mrigal (Cirrhinus mrigala) and the rohu (Labeo rohita).
Changes in the riffle macroinvertebrate fauna of the Tanjil river, Southeastern Australia, during construction of Blue Rock Dam
Authors: Chessman Bruce C. , Robinson David P. , Hortle Kent G. 
Published: February 2007

AbstractMacroinvertebrates were sampled from riffles upstream and downstream of the Blue Rock Dam construction site and inundation area in late November/early December 1979 (before construction) and 1982 (late in construction). Changes in the downstream fauna were much less than at some other large dam sites in Australia, probably because of improved erosion control. At the downstream sampling stations the total number of taxa collected was similar in both years, but there was a 30‐40 per cent reduction in faunal density; no significant change in density occurred at the upstream station. Multivariate analysis showed that the degree of change in faunal composition between years was similar at upstream and downstream stations. The proportion of fine (<4 mm) inorganic sediment in the streambed increased significantly at downstream stations over the study period, while there was no signficant change upstream. Silt (<250μm) also increased significantly downstream, but never exceeded 1 per cent of inorganic bed material.
River regulation in Spain
Authors: de Jalón Diego García 
Published: February 2007

AbstractThe expansion of river regulation and of related scientific research in Spain since 1982 is reviewed. The number of dams completed each year has decreased and, moreover, the average size of reservoir has continued to decline. It is the creation of many new, relatively small, irrigation reservoirs that is having the greatest impact on the fluvial systems. Recent legislation may promote greater involvement of scientists in the management of these systems not least in the setting of minimum ecological flows.
Food habits of migrating salmonid smolts passing bonneville dam in the Columbia river, 1984
Authors: Muir William D. , Emmett Robert L. 
Published: February 2007

AbstractThe food habits of migrating juvenile steelhead (Salmo gairdneri), sockeye salmon (Oncorhynchus nerka), coho salmon (O. kisutch), and chinook salmon (O. tshawytscha) were identified from April through August 1984 at Bonneville Dam in the Columbia River. During the spring (April‐June), the gammarid amphipods Corophium salmonis and C. spinicorne were the dominant prey for all species. Many insect taxa were also consumed, but in small quantities. Significant diet overlap occurred between all species during the spring due to the importance of Corophium. In summer (July‐August), the importance of Corophium declined in the diet of subyearling chinook salmon and was replaced with Daphnia spp. and adult dipterans (primarily chironomids).