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Simultaneous Analysis (simultaneous + analysis)
Selected AbstractsSimultaneous Analysis of Spatio-Temporal Gene Expression for Cephamycin Biosynthesis in StreptomycesclavuligerusBIOTECHNOLOGY PROGRESS, Issue 6 2001Yun Seung Kyung Linkage between structural and regulatory genes implies that a direct correlation should exist between the spatio-temporal distribution of their expression. Green fluorescent protein (GFP) and cyan fluorescent protein (CFP) were used as reporters to analyze simultaneously expression of lysine-,-aminotransferase (LAT) and its corresponding genetic regulator, CcaR. The isogenic strain containing lat::gfp and ccaR::cfp in the chromosome produced cephamycin C at levels similar to wild type Streptomyces clavuligerus. Confocal laser scanning microscopy revealed that expression of both LAT and CcaR in liquid culture was temporally dynamic and spatially heterogeneous in S.clavuligerus mycelia. During the early culture stage only a part of the mycelia began to express LAT and CcaR at low levels. As the culture aged, expression levels and the population of mycelia expressing LAT and CcaR increased and were followed late in the growth cycle by a reduction of the mycelia population expressing LAT and CcaR. The approach provides a precise simultaneous temporal-spatial expression profile and corroborates the regulatory linkage between ccaR and lat in S. clavuligerus. [source] Simultaneous analyses and applications of multiple fluorobenzoate and halide tracers in hydrologic studiesHYDROLOGICAL PROCESSES, Issue 14 2005Qinhong Hu Abstract An analytical method that employs ion chromatography has been developed to exploit the use of fluorobenzoic acids (FBAs) and halides more fully as hydrologic tracers. In a single run, this reliable, sensitive, and robust method can simultaneously separate and quantify halides (fluoride, chloride, bromide, and iodide) and up to seven FBAs from other common groundwater constituents (e.g. nitrate and sulphate). The usefulness of this analytical method is demonstrated in both field and laboratory tracer experiments. The field study examines the hydrologic response of fractures and the matrix to different flow rates and the contribution of matrix diffusion in chemical transport. Laboratory tracer experiments with eight geologic media from across the USA,mostly from Department of Energy facilities where groundwater contamination is prevalent and where subsurface characterization employing tracers has been ongoing or is in need,reveal several insights about tracer transport behaviour: (1) bromide and FBAs are not always transported conservatively; (2) the delayed transport of these anionic tracers is likely related to geologic media characteristics, such as organic matter, pH, iron oxide content, and clay mineralogy; (3) use of iodine as a hydrologic tracer should take into account the different sorption behaviours of iodide and iodate and the possible conversion of iodine's initial chemical form; (4) the transport behaviour of potential FBA and halide tracers under relevant geochemical conditions should be evaluated before beginning ambitious, large-scale field tracer experiments. Copyright © 2005 John Wiley & Sons, Ltd. [source] SIAM-Like Phenomenon Caused by Low Doses of AlcoholALCOHOLISM, Issue 2010Akiko Shimamoto Background:, Swift increase in alcohol metabolism (SIAM) is usually evoked by a large dose of ethanol, which is often demonstrated by an abrupt increase in oxygen uptake. SIAM was induced by low doses of ethanol and evaluated by pharmacokinetic analyses of ethanol and its metabolites. Methods:, Rabbits were initially administered 1.0 g/kg of ethanol solution and the same dose was given to the bolus group 6 hours after the first injection. The infusion group was administered 0.25 g/kg/h of ethanol 2 hours after the first injection. Blood concentrations of ethanol, acetaldehyde, and acetate were then determined and comparisons were made using pharmacokinetic parameters. Results:, A significantly higher ethanol elimination rate was observed after re-administration of ethanol to the bolus group. Other pharmacokinetic parameters were unaffected. The concentration at steady state (Css) for the infusion group was stable. A significantly higher level of mean residence time (MRT) in blood acetaldehyde was observed for the bolus group, whereas no MRT changes were observed for the infusion group. A significantly higher level of blood acetate Css was observed after re-administration of ethanol to the bolus group, following the changes in area under concentration and MRT. No Css changes were observed for the infusion group. The Css of acetate at stage 2 was significantly higher for the bolus group, compared to the infusion group. Conclusion:, Low doses of ethanol enhanced alcohol metabolism in rabbits, according to a pharmacokinetic analysis of circulating ethanol concentrations. Simultaneous analyses of its metabolites followed the kinetic of ethanol. [source] Enhanced Resolution of Copper and Bismuth by Addition of Gallium in Anodic Stripping Voltammetry with the Bismuth Film ElectrodeELECTROANALYSIS, Issue 24 2006Chad Prior Abstract This paper presents the enhanced analysis of copper on a bismuth electrode upon addition of gallium(III). The presence of gallium alleviates the problems of overlapping stripping signals usually observed between copper and bismuth when using the Bismuth Film Electrode. In addition, it has been found that the presence of gallium improves the reproducibility of the bismuth stripping signal. Simultaneous deposition of copper and bismuth at ,1500,mV for 2,minutes in a supporting electrolyte composed of 0.1,M pH,4.75 acetate buffer with 250,,g L,1 gallium yields well resolved copper and bismuth signals when analyzed with square-wave anodic stripping voltammetry. Simultaneous analysis of copper and lead yielded linear calibration plots in the range 10 to 100,,g L,1 with regression coefficients of 0.997 and 0.994 respectively. The theoretical detection limit for copper was calculated to be 4.98,,g L,1 utilizing a 2,minutes deposition time. The relative standard deviation for a copper concentration of 50,,g L,1 was 1.6% (n=10). [source] Simultaneous analysis of multiple PCR amplicons enhances capillary SSCP discrimination of MHC allelesELECTROPHORESIS, Issue 8 2010Miguel Alcaide Abstract Major histocompatibility complex (MHC) genotyping still remains one of the most challenging issues for evolutionary ecologists. To date, none of the proposed methods have proven to be perfect, and all provide both important pros and cons. Although denaturing capillary electrophoresis has become a popular alternative, allele identification commonly relies upon conformational polymorphisms of two single-stranded DNA molecules at the most. Using the MHC class II (, chain, exon 2) of the black kite (Aves: Accipitridae) as our model system, we show that the simultaneous analysis of overlapping PCR amplicons from the same target region substantially enhances allele discrimination. To cover this aim, we designed a multiplex PCR capable to generate four differentially sized and labeled amplicons from the same allele. Informative peaks to assist allele calling then fourfold those generated by the analysis of single PCR amplicons. Our approach proved successful to differentiate all the alleles (N=13) isolated from eight unrelated birds at a single optimal run temperature and electrophoretic conditions. In particular, we emphasize that this approach may constitute a straightforward and cost-effective alternative for the genotyping of single or duplicated MHC genes displaying low to moderate sets of divergent alleles. [source] Simultaneous analysis of the behavioural phenotype, physical factors, and parenting stress in people with Cornelia de Lange syndromeJOURNAL OF INTELLECTUAL DISABILITY RESEARCH, Issue 7 2009J. Wulffaert Abstract Background Studies into the phenotype of rare genetic syndromes largely rely on bivariate analysis. The aim of this study was to describe the phenotype of Cornelia de Lange syndrome (CdLS) in depth by examining a large number of variables with varying measurement levels. Virtually the only suitable multivariate technique for this is categorical principal component analysis. The characteristics of the CdLS phenotype measured were also analysed in relation to parenting stress. Method Data for 37 children and adults with CdLS were collected. The type of gene mutation and relevant medical characteristics were measured. Information on adaptive functioning, behavioural problems, the presence of the autistic disorder and parenting stress were obtained through questionnaires and semi-structured interviews with the parents. Chronological age and gender were also included in the analysis. Results All characteristics measured, except gender, were highly interrelated and there was much variability in the CdLS phenotype. Parents perceived more stress when their children were older, were lower functioning, had more behavioural problems, and if the autistic disorder was present. A new perspective was acquired on the relation between the gene mutation type and medical and behavioural characteristics. In contrast with earlier research the severity of medical characteristics did not appear a strong prognostic factor for the level of development. Conclusion Categorical principal component analysis proved particularly valuable for the description of this small group of participants given the large number of variables with different measurement levels. The success of the technique in the present study suggests that a similar approach to the characterisation of other rare genetic syndromes could prove extremely valuable. Given the high variability and interrelatedness of characteristics in CdLS persons, parents should be informed about this differentiated perspective. [source] Simultaneous analysis of nine active components in Gegen Qinlian preparations by high-performance liquid chromatography with diode array detectionJOURNAL OF SEPARATION SCIENCE, JSS, Issue 14 2006Lihong Chen Abstract HPLC with diode array detection (HPLC/DAD) was employed to determine the quantities of puerarin, daidzin, daidzein, berberine, palmatine, coptisine, baicalin, baicalein, and glycyrrhizin in Gegen Qinlian preparations of three different pharmaceutical forms including decoction, dispensing granule and pill. The calibration curves for the nine bioactive components were linear in the given concentration ranges. The precision of the method was in the range of 0.2,5.0% (RSD), and the recoveries of this method were between 96.5 and 104.1%. The proposed method was applicable to analyze Gegen Qinlian preparations. [source] Simultaneous analysis of basal Hymenoptera (Insecta): introducing robust-choice sensitivity analysisBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2003SUSANNE SCHULMEISTER Molecular characters are analysed on their own and in combination with morphological data to examine the phylogenetic relationships of the basal lineages of Hymenoptera (,Symphyta'). This study covers 47 sawfly genera and nine apocritan families and includes molecular sequences from five genes , 12S, 16S, 18S and 28S ribosomal genes and cytochrome oxidase 1 , as well as 343 morphological characters. A robust-choice sensitivity analysis is performed with the data. First, the simultaneous analysis is repeated three times, each time employing a different step matrix for weighting the transformations of the molecular characters. Then, the results of all three simultaneous analyses are summarized in a strict consensus in order to avoid basing the conclusions on a narrow set of assumptions. This methodology is discussed in the paper. The relationships among superfamilies largely confirm previous hypotheses, being (Xyeloidea (Tenthredinoidea s.l. (Pamphilioidea (Cephoidea (Siricoidea (Xiphydrioidea (Orussoidea Apocrita))))))), where Siricoidea is understood as Siricidae+Anaxyelidae. However, the relationships within Tenthredinoidea s.s. proposed here are novel: ({Argidae Pergidae}[Athalia{(Diprionidae Cimbicidae) Tenthredinidae minus Athalia}]). © 2003 The Linnean Society of London. Biological Journal of the Linnean Society, 2003, 79, 245,275. [source] Simultaneous analysis of catechol- O -methyl transferase activity, S -adenosylhomocysteine and adenosineBIOMEDICAL CHROMATOGRAPHY, Issue 3 2010Ilkka Reenilä Abstract Novel HPLC method utilizing UV-detection was developed to analyse catechol- O -methyltransferase (COMT) products, vanillic acid and isovanillic acid, S -adenosylhomocysteine (SAH) and adenosine formed from dihydroxybenzoic acid and S -adenosyl-L-methionine (SAM) by incubation of the rat tissues. Entacapone, a COMT inhibitor, prevented the formation of SAH only partially in the striatal homogenate whereas in the kidney homogenate the increase of SAH was prevented by entacapone. In conclusion, this method was reliable, rapid and simple. COMT seemed to be partially responsible on the SAM utilizing methylations in the striatal homogenates while in the high COMT activity tissue, COMT was the main SAH producing methyltransferase. Copyright © 2009 John Wiley & Sons, Ltd. [source] Simultaneous analysis of physiological and electrical output changes in an operating microbial fuel cell with Shewanella oneidensis,BIOTECHNOLOGY & BIOENGINEERING, Issue 3 2009Justin C. Biffinger Abstract Changes in metabolism and cellular physiology of facultative anaerobes during oxygen exposure can be substantial, but little is known about how these changes connect with electrical current output from an operating microbial fuel cell (MFC). A high-throughput voltage based screening assay (VBSA) was used to correlate current output from a MFC containing Shewanella oneidensis MR-1 to carbon source (glucose or lactate) utilization, culture conditions, and biofilm coverage over 250 h. Lactate induced an immediate current response from S. oneidensis MR-1, with both air-exposed and anaerobic anodes throughout the duration of the experiments. Glucose was initially utilized for current output by MR-1 when cultured and maintained in the presence of air. However, after repeated additions of glucose, the current output from the MFC decreased substantially while viable planktonic cell counts and biofilm coverage remained constant suggesting that extracellular electron transfer pathways were being inhibited. Shewanella maintained under an anaerobic atmosphere did not utilize glucose consistent with literature precedents. Operation of the VBSA permitted data collection from nine simultaneous S. oneidensis MR-1 MFC experiments in which each experiment was able to demonstrate organic carbon source utilization and oxygen dependent biofilm formation on a carbon electrode. These data provide the first direct evidence of complex cellular responses to electron donor and oxygen tension by Shewanella in an operating MFC at select time points. Biotechnol. Bioeng. 2009;103: 524,531. Published 2009 Wiley Periodicals, Inc. [source] Sources of character conflict in a clade of water striders (Heteroptera: Gerridae)CLADISTICS, Issue 6 2003Jakob Damgaard Incongruence among trees reconstructed with different data may stem from historical (gene tree-species tree conflict) or process (character change biases) phenomena. Regardless of the source, incongruent data, as determined with "global" measures of homoplasy, have often been excluded from parsimony analysis of the combined data. Recent studies suggest that these homoplasy measures do not predict the contribution of each character to overall tree structure. Branch support measures identify, on a character to node basis, sources of support and conflict resulting from a simultaneous analysis of the data. We implement these branch support measures to identify sources of character conflict in a clade of water striders consisting of Gerris Fabricius, Aquarius Schellenberg, and Limnoporus Stål species. Separate analyses of morphology, mitochondrial cytochrome oxidase I (COI), large mitochondrial ribosomal subunit (16SrRNA), and elongation factor-1, (EF-1,) data resulted in cladograms that varied in resolution and topological concordance. Simultaneous analysis of the data resulted in two trees that were unresolved for one node in a strict consensus. The topology agreed with current classification except for the placements of Aquarius chilensis and the Aquarius remigis species group closer to Gerris than to congeneric species. Branch support measures indicated that support derived from each data set varied among nodes, but COI had an overall negative effect on branch support. However, Spearman rank correlation of partitioned branch support values indicated no negative associations of branch support between any data sets and a positive association between EF-1, and 16SrRNA. Thus incongruence among data sets was not drastic and the gene-tree versus species tree phenomenon was not implicated. Biases in character change were a more likely reason for incongruence, although saturation curves and incongruence length difference for COI indicated little potential for homoplasy. However, a posteriori inspection of COI nucleotide change with reference to the simultaneous analysis tree revealed AT and codon biases. These biases were not associated with branch support measures. Therefore, it is difficult to predict incongruence or identify its cause. Exclusion of data is ill advised because every character is potentially parsimony informative. [source] High-performance liquid chromatography with sequential injection for online precolumn derivatization of some heavy metalsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 16 2007Rodjana Burakham Abstract HPLC was coupled with sequential injection (SI) for simultaneous analyses of some heavy metals, including Co(II), Ni(II), Cu(II), and Fe(II). 2-(5-Nitro-2-pyridylazo)-5-[N -propyl- N -(3-sulfopropyl)amino]phenol (nitro-PAPS) was employed as a derivatizing reagent for sensitive spectrophotometric detection by online precolumn derivatization. The SI system offers an automated handling of sample and reagent, online precolumn derivatization, and propulsion of derivatives to the HPLC injection loop. The metal,nitro-PAPS complexes were separated on a C18 -,Bondapak column (3.9×300 mm2). Using the proposed SI-HPLC system, determination of four metal ions by means of nitro-PAPS complexes was achieved within 13 min in which the parallel of derivatization and separation were processed at the same time. Linear calibration graphs were obtained in the ranges of 0.005,0.250 mg/L for Cu(II), 0.007,1.000 mg/L for Co(II), 0.005,0.075 mg/L for Ni(II), and 0.005,0.100 mg/L for Fe(II). The system provides means for automation with good precision and minimizing error in solution handling with the RSD of less than 6%. The detection limits obtained were 2 ,g/L for Cu(II) and Co(II), and 1 ,g/L for Ni(II) and Fe(II). The method was successfully applied for the determination of metal ions in various samples, including milk powder for infant, mineral supplements, local wines, and drinking water. [source] Simultaneous analysis of basal Hymenoptera (Insecta): introducing robust-choice sensitivity analysisBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2003SUSANNE SCHULMEISTER Molecular characters are analysed on their own and in combination with morphological data to examine the phylogenetic relationships of the basal lineages of Hymenoptera (,Symphyta'). This study covers 47 sawfly genera and nine apocritan families and includes molecular sequences from five genes , 12S, 16S, 18S and 28S ribosomal genes and cytochrome oxidase 1 , as well as 343 morphological characters. A robust-choice sensitivity analysis is performed with the data. First, the simultaneous analysis is repeated three times, each time employing a different step matrix for weighting the transformations of the molecular characters. Then, the results of all three simultaneous analyses are summarized in a strict consensus in order to avoid basing the conclusions on a narrow set of assumptions. This methodology is discussed in the paper. The relationships among superfamilies largely confirm previous hypotheses, being (Xyeloidea (Tenthredinoidea s.l. (Pamphilioidea (Cephoidea (Siricoidea (Xiphydrioidea (Orussoidea Apocrita))))))), where Siricoidea is understood as Siricidae+Anaxyelidae. However, the relationships within Tenthredinoidea s.s. proposed here are novel: ({Argidae Pergidae}[Athalia{(Diprionidae Cimbicidae) Tenthredinidae minus Athalia}]). © 2003 The Linnean Society of London. Biological Journal of the Linnean Society, 2003, 79, 245,275. [source] Diagnosing PNH with FLAER and multiparameter flow cytometryCYTOMETRY, Issue 3 2007D. Robert Sutherland Abstract Background: PNH is an acquired hematopoietic stem cell disorder leading to a partial or absolute deficiency of all glycophosphatidyl-inositol (GPI)-linked proteins. The classical approach to diagnosis of PNH by cytometry involves the loss of at least two GPI-linked antigens on RBCs and neutrophils. While flow assays are more sensitive and specific than complement-mediated lysis or the Hams test, they suffer from several drawbacks. Bacterial aerolysin binds to the GPI moiety of cell surface GPI-linked molecules and causes lysis of normal but not GPI-deficient PNH cells. FLAER is an Alexa488-labeled inactive variant of aerolysin that does not cause lysis of cells. Our goals were to develop a FLAER-based assay to diagnose and monitor patients with PNH and to improve detection of minor populations of PNH clones in other hematologic disorders. Methods: In a single tube assay, we combined FLAER with CD45, CD33, and CD14 allowing the simultaneous analysis of FLAER and the GPI-linked CD14 structure on neutrophil and monocyte lineages. Results: Comparison to standard CD55 and CD59 analysis showed excellent agreement. Because of the higher signal to noise ratio, the method shows increased sensitivity in our hands over single (CD55 or CD59) parameter analysis. Using this assay, we were able to detect as few as 1% PNH monocytes and neutrophils in aplastic anemia, that were otherwise undetectable using CD55 and CD59 on RBC's. We also observed abnormal FLAER staining of blast populations in acute leukemia. In these cases, the neutrophils stained normally with FLAER, while the gated CD33bright cells failed to express normal levels of CD14 and additionally showed aberrant CD45 staining and bound lower levels of FLAER. Conclusion: FLAER combined with multiparameter flow cytometry offers an improved assay for diagnosis and monitoring of PNH clones and may have utility in detection of unsuspected myeloproliferative disorders. © 2007 Clinical Cytometry Society [source] Detection of tumor cells in body cavity fluids by flow cytometric and immunocytochemical analysisDIAGNOSTIC CYTOPATHOLOGY, Issue 8 2006Awtar Krishan Ph.D. Abstract Measurement of electronic volume versus DNA content of nuclei can be used to discriminate between normal and malignant cells. Epithelial membrane antigen immunocytochemistry (EMA-ICC), a helpful ancillary test in body cavity fluids, is not universally accurate for detecting malignancy in effusions. The current study was undertaken to determine if multiparametric flow cytometry (based on simultaneous analysis of light scatter, nuclear volume, DNA, and nuclear protein content) in combination with (EMA-ICC) could be used for the detection of malignant cells in peritoneal and pleural fluids. We studied 130 body cavity fluids (68 peritoneal and 62 pleural fluids) by conventional cytology and multiparametric laser flow cytometry. EMA-ICC was performed using EMA antibodies and L-SAB detection system (DakoCytomation, Carpinteria, CA). EMA-ICC had significantly higher sensitivity than conventional cytology (79% versus 59%, P = 0.016) and ploidy (79% versus 38%, P = 0.001). Cytology had significantly higher specificity than ploidy (97% versus 82%, P = 0.012). The differences in specificity between EMA-ICC and ploidy (87% versus 82%, P= 0.607) or EMA-ICC and cytology (87% versus 97%, P = 0.109) were not statistically significant. However, assuming serial testing, sensitivity increased significantly for the combinations of cytology and EMA-ICC (79.4%, P = 0.016) and cytology and ploidy (73.5%, P = 0.004) as compared to cytology alone (58.8%). Also, the combination of cytology and ploidy had a higher sensitivity than ploidy alone (73% versus 38%, P < 0.0001). However, the sensitivity associated with the three tests used in serial (85.3%) was not significantly different from the sensitivities corresponding to the combination of cytology and EMA-ICC (79%) or cytology and ploidy (73%). Multiparametric flow cytometry utilizing high resolution DNA, nuclear volume, protein measurement, and ICC, in combination with cytomorphology, may be a valuable tool for rapid identification of malignant cells in body cavity fluids. Diagn. Cytopathol. 2006;34:528,541. © 2006 Wiley-Liss, Inc. [source] Predicting species distributions from museum and herbarium records using multiresponse models fitted with multivariate adaptive regression splinesDIVERSITY AND DISTRIBUTIONS, Issue 3 2007Jane Elith ABSTRACT Current circumstances , that the majority of species distribution records exist as presence-only data (e.g. from museums and herbaria), and that there is an established need for predictions of species distributions , mean that scientists and conservation managers seek to develop robust methods for using these data. Such methods must, in particular, accommodate the difficulties caused by lack of reliable information about sites where species are absent. Here we test two approaches for overcoming these difficulties, analysing a range of data sets using the technique of multivariate adaptive regression splines (MARS). MARS is closely related to regression techniques such as generalized additive models (GAMs) that are commonly and successfully used in modelling species distributions, but has particular advantages in its analytical speed and the ease of transfer of analysis results to other computational environments such as a Geographic Information System. MARS also has the advantage that it can model multiple responses, meaning that it can combine information from a set of species to determine the dominant environmental drivers of variation in species composition. We use data from 226 species from six regions of the world, and demonstrate the use of MARS for distribution modelling using presence-only data. We test whether (1) the type of data used to represent absence or background and (2) the signal from multiple species affect predictive performance, by evaluating predictions at completely independent sites where genuine presence,absence data were recorded. Models developed with absences inferred from the total set of presence-only sites for a biological group, and using simultaneous analysis of multiple species to inform the choice of predictor variables, performed better than models in which species were analysed singly, or in which pseudo-absences were drawn randomly from the study area. The methods are fast, relatively simple to understand, and useful for situations where data are limited. A tutorial is included. [source] Defining the moment of erosion: the principle of thermal consonance timingEARTH SURFACE PROCESSES AND LANDFORMS, Issue 13 2005D. M. LawlerArticle first published online: 9 DEC 200 Abstract Geomorphological process research demands quantitative information on erosion and deposition event timing and magnitude, in relation to fluctuations in the suspected driving forces. This paper establishes a new measurement principle , thermal consonance timing (TCT) , which delivers clearer, more continuous and quantitative information on erosion and deposition event magnitude, timing and frequency, to assist understanding of the controlling mechanisms. TCT is based on monitoring the switch from characteristically strong temperature gradients in sediment, to weaker gradients in air or water, which reveals the moment of erosion. The paper (1) derives the TCT principle from soil micrometeorological theory; (2) illustrates initial concept operationalization for field and laboratory use; (3) presents experimental data for simple soil erosion simulations; and (4) discusses initial application of TCT and perifluvial micrometeorology principles in the delivery of timing solutions for two bank erosion events on the River Wharfe, UK, in relation to the hydrograph. River bank thermal regimes respond, as soil temperature and energy balance theory predicts, with strong horizontal thermal gradients (often >1 K cm,1 over 6·8 cm). TCT fixed the timing of two erosion events, the first during inundation, the second 19 h after the discharge peak and 13 h after re-emergence from the flow. This provides rare confirmation of delayed bank retreat, quantifies the time-lag involved, and suggests mass failure processes rather than fluid entrainment. Erosion events can be virtually instantaneous, implying ,catastrophic retreat' rather than ,progressive entrainment'. Considerable potential exists to employ TCT approaches for: validating process models in several geomorphological contexts; assisting process identification and improving discrimination of competing hypotheses of process dominance through high-resolution, simultaneous analysis of erosion and deposition events and driving forces; defining shifting erodibility and erosion thresholds; refining dynamic linkages in event-based sediment budget investigations; and deriving closer approximations to ,true' erosion and deposition rates, especially in self-concealing scour-and-fill systems. Copyright © 2005 John Wiley & Sons, Ltd. [source] Simultaneous Quantification of Heavy Metals Using a Solid State Potentiometric Sensor ArrayELECTROANALYSIS, Issue 8 2009Jesús Gismera Abstract A potentiometric sensor array of four nonspecific electrodes with solid-state membranes is developed and tested for simultaneous analysis of copper(II), mercury(II), and silver(I) ions. The cross-sensitivity responses of the sensors for these ions are evaluated. The array potentiometric signals are processed by partial least-squares regression (PLS) and back propagation artificial neural networks (ANN) to determinate analyte concentrations. The ANN configuration is optimized and two different training algorithms of the ANN are also evaluated. Best results are obtained when the potentiometric sensors are activated and the data are processed using ANN and the gradient descent adaptive algorithm. The system is used to quantify these heavy metals in synthetic samples and in dental amalgams with successful results. [source] Simultaneous analysis of multiple PCR amplicons enhances capillary SSCP discrimination of MHC allelesELECTROPHORESIS, Issue 8 2010Miguel Alcaide Abstract Major histocompatibility complex (MHC) genotyping still remains one of the most challenging issues for evolutionary ecologists. To date, none of the proposed methods have proven to be perfect, and all provide both important pros and cons. Although denaturing capillary electrophoresis has become a popular alternative, allele identification commonly relies upon conformational polymorphisms of two single-stranded DNA molecules at the most. Using the MHC class II (, chain, exon 2) of the black kite (Aves: Accipitridae) as our model system, we show that the simultaneous analysis of overlapping PCR amplicons from the same target region substantially enhances allele discrimination. To cover this aim, we designed a multiplex PCR capable to generate four differentially sized and labeled amplicons from the same allele. Informative peaks to assist allele calling then fourfold those generated by the analysis of single PCR amplicons. Our approach proved successful to differentiate all the alleles (N=13) isolated from eight unrelated birds at a single optimal run temperature and electrophoretic conditions. In particular, we emphasize that this approach may constitute a straightforward and cost-effective alternative for the genotyping of single or duplicated MHC genes displaying low to moderate sets of divergent alleles. [source] CE-TOF MS analysis of complex protein hydrolyzates from genetically modified soybeans , A tool for foodomicsELECTROPHORESIS, Issue 7 2010Carolina Simó Abstract A CE-TOF MS proteomic approach was applied for the analysis of hydrolyzates from complex soybean protein mixtures. After CE-TOF MS method development, the new approach provided the simultaneous analysis of more than 150 peptides from the soybean protein fraction soluble in ACN-water (80/20,v/v). The method is fast (about 30,min of analysis per sample) and is characterized by a relatively low running cost. The approach was used to study the substantial equivalence between a genetically modified variety of soybean compared with its traditional counterpart. No significant differences were found between the two studied soybeans based on the protein fraction studied. The capacity of the CE-TOF MS method to analyze complex mixtures of peptides in short times opens interesting possibilities in the growing Foodomics area. [source] Enantioselective analysis of ketamine and its metabolites in equine plasma and urine by CE with multiple isomer sulfated ,-CDELECTROPHORESIS, Issue 15 2007Regula Theurillat Abstract CE with multiple isomer sulfated ,-CD as the chiral selector was assessed for the simultaneous analysis of the enantiomers of ketamine and metabolites in extracts of equine plasma and urine. Different lots of the commercial chiral selector provided significant changes in enantiomeric ketamine separability, a fact that can be related to the manufacturing variability. A mixture of two lots was found to provide high-resolution separations and interference-free detection of the enantiomers of ketamine, norketamine, dehydronorketamine, and an incompletely identified hydroxylated metabolite of norketamine in liquid/liquid extracts of the two body fluids. Ketamine, norketamine, and dehydronorketamine could be unambiguously identified via HPLC fractionation of urinary extracts and using LC-MS and LC-MS/MS with 1,mmu mass discrimination. The CE assay was used to characterize the stereoselectivity of the compounds' enantiomers in the samples of five ponies anesthetized with isoflurane in oxygen and treated with intravenous continuous infusion of racemic ketamine. The concentrations of the ketamine enantiomers in plasma are equal, whereas the urinary amount of R -ketamine is larger than that of S -ketamine. Plasma and urine contain higher S - than R -norketamine levels and the mean S -/R -enantiomer ratios of dehydronorketamine in plasma and urine are lower than unity and similar. [source] Capillary electrophoretic chiral separation of hydroxychloroquine and its metabolites in the microsomal fraction of liver homogenatesELECTROPHORESIS, Issue 5-6 2006Carmem Dickow Cardoso Abstract A rapid, selective, and low-cost chiral capillary electrophoretic method was developed for the simultaneous analysis of hydroxychloroquine (HCQ) and its three chiral metabolites: desethylchloroquine (DCQ), desethylhydroxychloroquine (DHCQ), and bisdesethylchloroquine (BDCQ) in the microsomal fraction of liver homogenates. After liquid,liquid extraction using toluene as extracting solvent, the drug and metabolites were resolved on a fused-silica capillary (50,,m ID, 50,cm total length, and 42,cm effective length), using 100,mmol/L of Tris/phosphate buffer, pH,9.0 containing 1% w/v sulfated-,-CD and 30,mg/mL hydroxypropyl-,-CD. Detection was carried out at 220,nm. The extraction procedure was efficient in removing endogenous interferents, and low values (,15%) for CVs and deviation from theoretical values were demonstrated for both within-day and between-day assays. The quantitation limit was 125,ng/mL with linear response over the 125,2000,ng/mL of concentration range for all metabolites. After validation, the method was used for an in vitro metabolism study of HCQ. The major HCQ metabolite formed by microsomal enzymes was (,)-(R)-DHCQ. [source] Poly(methacrylic acid-ethylene glycol dimethacrylate) monolith in-tube solid-phase microextraction applied to simultaneous analysis of some amphetamine derivatives in urine by capillary zone electrophoresisELECTROPHORESIS, Issue 16 2005Fang Wei Abstract A method based on in-tube solid-phase microextraction and capillary zone electrophoresis (CZE) was proposed for simultaneously determining four amphetamines (amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, and 3,4-methylenedioxymethamphetamine) in urine. A poly(methacrylic acid-ethylene glycol dimethacrylate) monolithic capillary column, which can provide sufficient extraction efficiency, was introduced for the extraction of amphetamines from urine samples. The hydrophobic main chains and acidic pendant groups of the monolithic column make it a superior material for extraction of basic analytes from aqueous matrix. After extraction, the samples were analyzed by CZE. The best separation was achieved using a buffer composed of 0.1,M disodium hydrogen phosphate (adjusted to pH,4.5 with 1,M hydrochloric acid) and 20% methanol v/v, with a temperature and voltage of 25°C and 20,kV, respectively. By applying electrokinetic injection with field-amplified sample stacking, detection limits of 25,34,µg/L were achieved. Excellent method of reproducibility was found over a linear range of 0.1,5,mg/L. Determination of these analytes from abusers' urine sample was also demonstrated. [source] Microchip capillary electrophoresis with a cellulose-DNA-modified screen-printed electrode for the analysis of neurotransmittersELECTROPHORESIS, Issue 15 2005Muhammad Johirul Abstract A microfluidic chip based on capillary electrophoresis coupled with a cellulose-single-stranded DNA (cellulose-ssDNA) modified electrode was used for the simultaneous analysis of dopamine (DA), norepinephrine (NE), 3,4-dihydroxy- L -phenylalanine (L -DOPA), 3,4-dihydroxyphenylacetic acid (DOPAC), and ascorbic acid (AA). The modification of the electrode improved the electrophoretic analysis performance by lowering the detection potential and enhancing the signal-to-noise characteristic without surface poisoning of the electrode. The sensitivity of the modified electrode was about 12 times higher than those of the bare ones. The test compounds were separated using a 62,mm long separation channel at the separation field strength of +200,V/cm within 220,s in a 10,mM phosphate buffer (pH,7.4). The most favorable potential for the amperometric detection was 0.7,V (vs. Ag/AgCl). A reproducible response (relative standard deviation of 1.3, 1.3, 2.1, 3.1, 3.4% for DA, NE, L -DOPA, DOPAC, and AA, respectively, for n,=,9) for repetitive sample injections reflected the negligible electrode fouling at the cellulose-ssDNA modified electrode. Square-wave voltammetric analyses reflected the sensitivities of the modified electrode for DA, NE, L -DOPA, DOPAC, and AA which were 1.78, 0.82, 0.69, 2.45, and 1.23,nC/µM with detection limits of 0.032, 0.93, 1.13, 0.31, and 0.62,µM, respectively. The applicability of this microsystem to real sample analysis was demonstrated. [source] Dual injection capillary electrophoresis: Foundations and applicationsELECTROPHORESIS, Issue 23-24 2004Feliciano Priego-Capote Abstract The state of the art of capillary electrophoresis (CE) approaches based on dual injection is here reported. Dual injection strategies have been proposed with three main objectives: (i) to provide information about reaction kinetics and/or related parameters, (ii) to perform in-capillary derivatization for improving separation and/or determination, (iii) to develop electrophoretic methods for the simultaneous analysis of anionic and cationic compounds. For the first two purposes, dual injection, which involves sample and reagent, can be realized either from the same end of the capillary (electrophoretically mediated microanalysis, EMMA) or from the two ends of the capillary (electroinjection analysis, EIA). The third objective, with dual injection of sample from the two ends of the capillary, takes advantage of moving cationic and anionic compounds with opposite directions. The foundations of each alternative, conditions necessary for working with them, restrictions, applications as well as perspectives are reviewed in order to establish the advantages, shortcomings, and convenience or no of their use in comparison to conventional CE. [source] Sensitive and simultaneous analysis of five transgenic maizes using multiplex polymerase chain reaction, capillary gel electrophoresis, and laser-induced fluorescenceELECTROPHORESIS, Issue 14 2004Virginia García-Cañas Abstract The benefits of using multiplex polymerase chain reaction (PCR) followed by capillary gel electrophoresis with laser-induced fluorescence (CGE-LIF) for the simultaneous detection of five transgenic maizes (Bt11, T25, MON810, GA21, and Bt176) are demonstrated. The method uses a hexaplex PCR protocol to amplify the five mentioned transgenic amplicons plus the zein gene used as reference, followed by a CGE-LIF method to analyze the six DNA fragments. CGE-LIF was demonstrated very useful and informative for optimizing multiplex PCR parameters such as time extension, PCR buffer concentration and primers concentration. The method developed is highly sensitive and allows the simultaneous detection in a single run of percentages of transgenic maize as low as 0.054% of Bt11, 0.057% of T25, 0.036% of MON810, 0.064% of GA21, and 0.018% of Bt176 in flour obtaining signals still far from the detection limit (namely, the signal/noise ratios for the corresponding DNA peaks were 41, 124, 98, 250, 252, and 473, respectively). These percentages are well below the minimum threshold marked by the European Regulation for transgenic food labeling (i.e., 0.5,0.9%). A study on the reproducibility of the multiplex PCR-CGE-LIF procedure was also performed. Thus, values of RSD lower than 0.67 and 6.80% were obtained for migration times and corrected peak areas, respectively, for the same sample and three different days (n = 12). On the other hand, the reproducibility of the whole procedure, including four different multiplex PCR amplifications, was determined to be better than 0.66 and 23.3% for migration times and corrected peak areas, respectively. Agarose gel electrophoresis (AGE) and CGE-LIF were compared in terms of resolution and sensitivity for detecting PCR products, demonstrating that CGE-LIF can solve false positives induced by artifacts from the multiplex PCR reaction that could not be addressed by AGE. Moreover, CGE-LIF provides better resolution and sensitivity. To our knowledge, these results demonstrate for the first time that multiplex PCR-CGE-LIF is a solid alternative to determine multiple genetically modified organisms in maize flours in a single run. [source] THE GEOGRAPHICAL PATTERN OF SPECIATION AND FLORAL DIVERSIFICATION IN THE NEOTROPICS: THE TRIBE SINNINGIEAE (GESNERIACEAE) AS A CASE STUDYEVOLUTION, Issue 7 2007Mathieu Perret The geographical pattern of speciation and the relationship between floral variation and species ranges were investigated in the tribe Sinningieae (Gesneriaceae), which is found mainly in the Atlantic forests of Brazil. Geographical distribution data recorded on a grid system of 0.5 × 0.5 degree intervals and a near-complete species-level phylogenetic tree of Sinningieae inferred from a simultaneous analysis of seven DNA regions were used to address the role of geographical isolation in speciation. Geographical range overlaps between sister lineages were measured across all nodes in the phylogenetic tree and analyzed in relation to relative ages estimated from branch lengths. Although there are several cases of species sympatry in Sinningieae, patterns of sympatry between sister taxa support the predominance of allopatric speciation. The pattern of sympatry between sister taxa is consistent with range shifts following allopatric speciation, except in one clade, in which the overlapping distribution of recent sister species indicates speciation within a restricted geographical area and involving changes in pollinators and habitats. The relationship between floral divergence and regional sympatry was also examined by analyzing floral contrasts, phenological overlap, and the degree of sympatry between sister clades. Morphological contrast between flowers is not increased in sympatry and phenological divergence is more apparent between allopatric clades than between sympatric clades. Therefore, our results failed to indicate a tendency for sympatric taxa to minimize morphological and phenological overlap (geographic exclusion and/or character displacement hypotheses). Instead, they point toward adaptation in phenology to local conditions and buildup of sympatries at random with respect to flower morphology. Additional studies at a lower geographical scale are needed to identify truely coexisting species and the components of their reproductive isolation. [source] Transgenic mice expressing a dual, CRE-inducible reporter for the analysis of axon guidance and synaptogenesis,GENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 6 2007Aurora Badaloni Abstract Improved and modular tools are needed for the neuroanatomical dissection of CNS axonal tracts, and to study the cell-intrinsic and cell-extrinsic cues that govern their assembly and plasticity. Here we describe a general purpose transgenic tracer that can be used to visualize axonal tracts and synaptic terminals in any region of the embryonic neural tube or postnatal CNS, on any wild type or mutant genetic background. The construct permits CRE-inducible expression of a dicistronic axonal marker encoding two surface reporter proteins: a farnesylated GFP and the human Placental Alkaline Phosphatase (PLAP). Both proteins localize alongside the neuronal surface, permitting the concomitant detection of cell body, neurites, and presynaptic and postsynaptic sites in the same neuron. This provides a CRE-inducible dual system for imaging neural circuits in vivo, and to study their assembly and remodeling in cultured neurons, neural stem cells, and tissue explants derived from the reporter line. Unlike existing lines, this reporter does not encode a ubiquitously expressed, floxable LacZ gene, permitting the simultaneous analysis of beta galactosidase activity in mutant lines. genesis 45:405,412, 2007. © 2007 Wiley-Liss, Inc. [source] A new multiparameter assay to assess HPV 16/18, viral load and physical status together with gain of telomerase genes in HPV-related cancersINTERNATIONAL JOURNAL OF CANCER, Issue 4 2010Wendy Theelen Abstract Oncogenic human papillomavirus (HPV) is the most important risk factor for cancer of the uterine cervix and a subgroup of head and neck cancers. Viral load has been associated with persistence of infection, whereas integration of HPV into the host cell genome is associated with transition to invasive disease. Viral integration is frequently correlated with loss of viral E2 and gain of the telomerase-related genes TERC and TERT. The objective of this study was to develop a rapid and sensitive multiplex ligation-dependent probe amplification (MLPA) assay for the simultaneous analysis of viral load, integration and copy number gain of TERC and TERT in HPV16/18-associated lesions. The performance of the assay was tested for HPV vs. human gene copy number ratios ranging from 0.1 to 100 and for percentages of integration ranging from 0 to 100%. The model systems used include plasmid mixtures and the HPV-positive cell lines SiHa, HeLa and CaSki described to contain a range of 2,600 viral copies per cell. In samples with low-viral load, viral integration can be reliably determined when more than 30% of the virus is integrated. Gain of the telomerase-related genes in the cell lines as determined by our MLPA assay was in accordance with data reported in the literature. Our study demonstrates that within a single MLPA-reaction viral type, load, integration and gain of TERC and TERT can be reliably determined, which will improve risk assessment for patients suspected for HPV infection. [source] Suitability of Molluscs as Bioindicators for Meadow- and Flood-Channels of the Elbe-FloodplainsINTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 4 2006Francis Foeckler Abstract The goals of the subproject "molluscs" within the inter-disciplinary research project "Indicator systems for the characterisation and prediction of ecological changes in floodplain systems" were: , develop further existing mollusc-based indicator systems of site quality and to test their transferability, , characterise grassland sites within the recent floodplains of three study areas along the Elbe River, , analyse the relationships between indicator species-/groups and abiotic parameters, , compile and use selected species traits in the analytical process. The results clearly show several characteristic species groups related to the hydrology of the sites (i.e. inundation and desiccation regime) and on to the degree of agricultural use. These dependencies can be interpreted by the simultaneous analysis of the species traits. "Models" are proposed, that are applicable to nature protection measures at the landscape scale. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||||||||||||||||||||