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PubMedDate not supplied

Isolation and analysis of moenomycin and its biosynthetic intermediates from Streptomyces ghanaensis (ATCC 14672) wildtype and selected mutants.

Streptomyces ghanaensis (ATCC 14672) produces the phosphoglycolipid antibiotic moenomycin consisting of several components. A solid phase extraction procedure was developed which allowed a rapid isolation of both moenomycin and its biosynthetic intermediates from culture filtrates. Semi-preparative high performance liquid chromatography followed by high performance liquid chromatography-mass spectrometry provided structural data on the different moenomycin components. In order to obtain initial information on the biosynthetic pathway, moenomycin non-producing mutants were isolated. They were shown to release intermediates with shorter lipid chains suggesting that the lipid chain synthesis probably takes place at a later stage of the moenomycin biosynthesis. Based on the biological activity and the analytical data, we assume that a modification and in particular a shorter lipid portion drastically influences the inhibitory activity of this antibiotic.

Anti-Bacterial Agents↗
PubMed1993

Graphical and statistical techniques for cardiac cycle time (phase) dependent changes in interbeat interval: problems with the Jennings et al. (1991) proposals.

Two apparently new effects in human cardiac responding, "primary bradycardia" and "vagal inhibition", were first described by the Laceys. These effects have been considered by some researchers to reflect differential cardiac innervation, analogous to similar effects observed in animal preparations with direct vagal stimulation. However, it has been argued that such effects arise merely from the data-analytic techniques introduced by the Laceys, and hence are not genuine cardiac cycle effects. Jennings, van der Molen, Somsen and Ridderinkhoff (Psychophysiology, 28 (1991) 596-606) recently proposed a plotting technique and statistical procedure in an attempt to resolve this issue. The present paper demonstrates that the plotting technique fails to achieve their stated aim, since it identifies data from identical cardiac responses as showing cardiac-cycle effects. In addition, the statistical procedure is shown to be reducible to a trivial test of response occurrence. The implication of these demonstrations, in the context of other work, is that this area of investigation has reached a dead end.

Arousal↗
PubMed1990

Spectral peak verification and recognition using a multilayered neural network.

The verification and recognition of peak-shaped signals in analytical data are ubiquitous scientific problems. Experimental data contain overlapping signals and noise, which make sensitive and reliable peak recognition difficult. A peak detection system based on a class of neural networks known as "multilayered perceptrons" has been created. The network was trained and evaluated with use of vapor-phase infrared spectral data. The results of varying the network architecture on system training and prediction performance along with refinement of the form of the input pattern are presented.

Artificial Intelligence↗
PubMedDate not supplied

Contrasts and correlations in theory assessment.

OBJECTIVE: To describe a systematic quantitative approach to assessing the predictions made by competing theories using contrasts and correlational indices of effect sizes. METHODS: We illustrate the use of the contrast F and t to compare and combine predictions when the raw data are continuous scores, and z contrasts when working with frequencies in 2 x k tables of counts. RESULTS: The traditional effect size correlation indicates the magnitude of the effect on individual scores of participants' assignment to particular conditions. The contrast correlation obtained from the contrast F or t is, in some cases, the easiest way of estimating the effect size correlation in designs using more than two groups. The alerting correlation is another way of appraising the predictive power of a contrast and can be used to compute the contrast F from published results when all we have are condition means and the omnibus F from an overall analysis of variance. Omnibus Fs, those with more than 1 df in the numerator, are rarely useful in data analytic work since they address unfocused questions, yielding only vague answers. CONCLUSIONS: Asking focused questions using contrasts increases the clarity of our questions and the clarity and statistical power of our answers.

Adolescent↗
PubMed2005

Principal opium alkaloids as possible biochemical markers for the source identification of Indian opium.

A total of 124 opium samples originating from different licit opium growing divisions of India were analyzed for their principal alkaloid (thebaine, codeine, morphine, papaverine, and narcotine) content by capillary zone electrophoresis (CZE) without derivatization or purification. Absence of papaverine in Bareilly, Tilhar, and most of the samples originating from Kota is a significant observation in relation to the source of Indian opium. Multiple discriminant analysis was applied to the quantitative principal alkaloid data to determine an optimal classifier in order to evaluate the source of Indian opium. The predictive value based on the discriminant analysis was found to be 85% in relation to the source of opium and the study also revealed that all the principal alkaloids have to be analyzed for source identification of Indian opium. Chemometrics performed with principal alkaloids analytical data was used successfully in discriminating the licit opium growing divisions of India into three major groups, viz., group I, II, and III. The methodology developed may find wide forensic application in identifying the source of licit or illicit opium originating from India, and to differentiate it from opium originating from other opium producing countries.

Chromatography, High Pressure Liquid↗
PubMed1989

Diagnostic value of ganglioside patterns in plasma of human diseases.

A method that could be facilitated for the quantitation and qualitation of gangliosides in human plasma was developed and applied in the present study for characterization of ganglioside patterns in plasmas of patients with neoplastic diseases including gastric cancer, adult T-cell leukemia (ATL), and acute lymphocytic leukemia (ALL). As a retrovirus-infected disease with different clinical entity, human T-cell lymphotropic virus type I-associated myelopathy (HAM) was also subjected to this study. The results were compared with the patterns obtained from normal control plasmas. The analytical data revealed that GM3 increased in gastric cancer, GT1b decreased in HAM and ATL, and GD3, GM1 and GM3 decreased in ALL. There were close correlations between various human diseases and the presence of gangliosides with their specific patterns. Furthermore, gangliosides purified from plasma of patients with HAM significantly inhibited the expression of CD4 antigen on human T lymphocyte membrane. Therefore, analytical studies of plasma gangliosides could provide diagnostic and therapeutic values in retroviral infections.

Adult↗
PubMed1987

Isolation, characterization, and biosynthesis of a phosphorylated glycoprotein from rat bone.

A phosphorylated glycoprotein was purified from the mixture of proteins extracted by demineralization of rat bone with 0.5 M EDTA in 4 M guanidinium chloride. A high level of purity for the preparation was indicated by a single band on sodium dodecyl sulfate (SDS)-gradient gel electrophoresis, sedimentation equilibrium ultracentrifugal data, and by automated Edman degradation results. The molecular weight of the phosphoprotein was shown to be about 44,000 by sedimentation equilibrium analyses in 4 M guanidinium chloride, even though an Mr of 75,000 was obtained by 5-15% SDS-polyacrylamide gel electrophoresis. Subsequent analysis by 15% SDS-polyacrylamide gel electrophoresis gave an Mr of 45,000. Analytical data showed that the protein contained 16.6% carbohydrate, possibly including 1 N-linked oligosaccharide and 5-6 O-linked oligosaccharides. The aspartic acid- and glutamic acid-rich protein contained about 300 amino acid residues including 1 phosphothreonine and 12 phosphoserine residues. Alkaline beta-elimination/NaBH4 reduction data showed that the phosphate obtained by complete acid hydrolysis prior to amino acid analysis was equivalent to the phosphate subject to alkaline beta-elimination. In this experiment, the losses of serine plus threonine exceeded the amount of phosphate liberated by 5-6 residues/protein. These serine and threonine residues probably represent O-linked oligosaccharides, since the protein contained about this number of N-acetyl-galactosamine residues. That the phosphoprotein is synthesized and secreted by osteoblast-like cells was shown with cultures of clonal rat osteosarcoma cells. After pulsing with 32PO4 the proteins secreted into the medium were precipitated with trichloroacetic acid and the radiolabeled proteins were immunoadsorbed. A protein migrating in the same position, on 5-15% SDS-polyacrylamide gel electrophoresis (i.e. with an Mr = 75,000) and on 15% gels (Mr = 45,000), as the phosphoprotein obtained from bone could be specifically immunoprecipitated.

Amino Acids↗
PubMed1989

The spectroscopic analysis for binding of amphipathic and antimicrobial model peptides containing pyrenylalanine and tryptophan to lipid bilayer.

The binding of basic amphipathic fluorescent peptides to lipid bilayers was studied in relation to their antimicrobial activity. Four fluorescent peptides containing pyrenylalanine or tryptophan in an amphipathic basic peptide (4(4] consisting of four repeated units of tetrapeptide, -L-Leu-L-Ala-L-Arg-L-Leu-, were found to have antimicrobial activities against Gram-positive bacteria and to take conformations with fairly high alpha-helical content both in aqueous solutions and liposomes. The fluorescence spectroscopic data suggested that the pyrenylalanine-peptide existed as a monomer in methanol or liposomes but as an oligomer in aqueous solutions to form an excimer between pyrenylalanyl residues. Upon binding with liposomes, the fluorescence spectra of the tryptophan-containing peptide shifted to a shorter wavelength, indicating the change in the state of tryptophan from hydrophilic environment to hydrophobic one. The analytical data for the quenching of tryptophan fluorescence by I- anion suggest that the tryptophan residue in the peptide is not deeply buried in the hydrophobic core of the bilayers. Based on these findings, it is suggested that the peptides may interact with liposomes in such a manner that they lie parallel to the surface of the lipid bilayers with their hydrophobic regions shallowly in the amphipathic moiety of the bilayers.

Alanine↗
PubMedDate not supplied

Zherlock: an open source data analysis software.

Zherlock is an open source software that provides state-of-the-art data analysis tools to the user in an intuitive and flexible way. It is a front-end to different numerical "engines" to produce a seamless integration of algorithms written in different computer languages. Of particular interest is creating an interface to high-level scientific languages such as Octave (a Matlab clone) and R (an S-PLUS clone) to enable efficient porting of new data analytical methods. Zherlock uses advanced scientific visualization tools in 2-D and 3-D and has been extended to work on virtual reality (VR) systems. Central to Zherlock is a visual programming environment (VPE) which enables diagram based programming. These diagrams consist of nodes and connection lines where each node is an operator or a method and lines describe the flow of data between nodes. A VPE is chosen for Zherlock because it forms an effective way to control the processing pipeline in complex data analyses. The VPE is similar in functionality to other programs such as IRIS Explorer, AVS or LabVIEW.

Algorithms↗
PubMed2005

Analysis of glucosinolates, isothiocyanates, and amine degradation products in vegetable extracts and blood plasma by LC-MS/MS.

Dietary glucosinolates are under intensive investigation as precursors of cancer-preventive isothiocyanates. Quantitation of the dose and bioavailability of glucosinolates and isothiocyanates requires a comprehensive analysis of the major dietary glucosinolates, isothiocyanates, and related metabolites. We report a liquid chromatography with tandem mass spectrometric detection (LC-MS/MS) analytical method for the comprehensive analysis of the seven major dietary glucosinolates, related isothiocyanates, and putative amine degradation products. The parent glucosinolates were sinigrin, gluconapin, progoitrin, glucoiberin, glucoraphanin, glucoalyssin, and gluconasturtiin. The LC-MS/MS analysis method for these compounds was developed and validated; a standard addition analysis protocol was used generally to avoid the requirement for stable isotopic standards. Where stable isotopic standards were available, internal standardization with these gave estimates in agreement with those obtained by the standard addition analysis protocol. For glucosinolates, negative ion electrospray LC-MS/MS analysis was performed. Isothiocyanates and amines were prederivatized to the corresponding thiourea and N-acetamides, respectively, and were quantified by positive ion electrospray LC-MS/MS. The limits of detection were 0.5-2 pmol; the recoveries for glucosinolates, isothiocyanates, and amines were 85-90%, 50-85%, and 60-70%, respectively; and the intra- and interbatch coefficients of variation were 1-4% and 3-10%, respectively. These methods provide facile access to comprehensive analytical data on the major dietary glucosinolates and related metabolites to quantify inputs and metabolic formation of these compounds in cancer prevention and related studies.

Amines↗
PubMed2003

Training graduate-level pediatric psychology researchers at Case Western Reserve University: meeting the challenges of the new millennium.

OBJECTIVE: To describe the challenges in training graduate-level pediatric psychology researchers for successful careers and to discuss solutions. METHODS: We reviewed experiences in training graduate students at Case Western Reserve University to identify key challenges in research training and potential strategies to meet them. RESULTS: We identified the following key challenges: stimulating graduate students' career interest in pediatric psychology research; teaching students about the pragmatic challenges of conducting research in pediatric settings, specialized research design, and data analytic issues; helping students to develop essential research skills; developing opportunities for student research-related collaborations; helping students develop professional identities as researchers; and developing and supporting their research careers beyond graduate school. CONCLUSIONS: Useful strategies for meeting these challenges include involving an interdisciplinary faculty in research training; developing specialized training methods that focus on critical research skills such as writing and data analysis; peer support; and involvement with multiple mentors who are successful researchers. Pediatric psychologists should also develop opportunities for the next generation of researchers by facilitating research job options and leadership opportunities.

Child↗
PubMed1978

Alveolar phospholipids in pulmonary alveolar proteinosis.

The biochemical compositions of lung lavage fluid from three patients and that of the lung tissue obtained by a biopsy from a patient with alveolar proteinosis were analyzed. The lung lavage fluid was separated to the supernatant and the insoluble precipitate fractions by a brief centrifugation and the lung tissue was separated to surfactant and residual fractions by sucrose density gradient centrifugation. The supernatant of lung washing contained larger quantities of protein and less lipid which was mainly composed of lecithin and sphingomyelin. In contrast, the insoluble material of lung washing contained 4--8 fold of lipid as compared with the supernatant, and lecithin was a predominant phospholipid. From the analysis of fatty acid and individual molecular species of major phospholipids, the higher contents of dipalmitoyllecithin and sphingomyelin containing palmitate were found in the insoluble material. The phospholipid composition and fatty acid composition of lecithin were similar between the precipitate fraction of lung washing and the surfactant fraction of lung tissue. The ratio of protein to phospholipid in the precipitate fraction was similar to that of lung washing. These analytical data suggest that the materials accumulated in the alveoli of the patients may be derived mainly from the lung surfactant fraction. The metabolic studies showed that lecithin synthesis through de novo and lysolecithin pathways works in human lung with this disease as actively as in rat lung. The secretion of lung lecithin to the surfactant fraction also appeared to be normal. From these analytical and metabolic findings, the causes for the accumulation of the materials which cover alveolar surface and impair gaseous exchange in the alveoli of pulmonary alveolar proteinosis, were discussed.

Animals↗
PubMed2006

Reproducible epidemiologic research.

The replication of important findings by multiple independent investigators is fundamental to the accumulation of scientific evidence. Researchers in the biologic and physical sciences expect results to be replicated by independent data, analytical methods, laboratories, and instruments. Epidemiologic studies are commonly used to quantify small health effects of important, but subtle, risk factors, and replication is of critical importance where results can inform substantial policy decisions. However, because of the time, expense, and opportunism of many current epidemiologic studies, it is often impossible to fully replicate their findings. An attainable minimum standard is "reproducibility," which calls for data sets and software to be made available for verifying published findings and conducting alternative analyses. The authors outline a standard for reproducibility and evaluate the reproducibility of current epidemiologic research. They also propose methods for reproducible research and implement them by use of a case study in air pollution and health.

Air Pollution↗
PubMed1999

Improvement of the BCR three step sequential extraction procedure prior to the certification of new sediment and soil reference materials.

The Standards, Measurements and Testing Programme (formerly BCR) of the European Commission proposed a three-step sequential extraction procedure for sediment analysis, following extensive expert consultations and two interlaboratory studies. This scheme was recently used to certify the extractable trace element contents of a sediment reference material (CRM 601). Although this procedure offers a means to ensure the comparability of data in this field, some difficulties concerning the interlaboratory reproducibility still remain, and a new project is currently being conducted to determine the causes of poor reproducibility in the extraction scheme. The final objective of the project is the certification of new sediment and soil reference materials for their extractable contents of Cd, Cr, Cu, Ni, Pb and Zn. This paper presents the results of a small-scale interlaboratory study, which aimed to test a revised version of the extraction schemes by comparing the original and the modified protocols using the CRM 601 sample. This work offers an improvement to the BCR sequential extraction procedure through intercomparison exercises. This improved procedure will allow the obtaining of CRMs to validate analytical data in the analysis of soils and sediments, and it will also facilitate comparability of data in the European Union.

Calibration↗
PubMed1998

Common and specific features of childhood psychopathology.

This article describes a conceptual and data-analytic model for characterizing different levels of common and specific features of child psychopathology: common features, which differentiate psychopathology from normality; broadband-specific features, which differentiate internalizing problems (e.g., anxiety, somatization) from externalizing problems (e.g., aggression, hyperactivity); and narrowband-specific features, which differentiate different narrowband syndromes (e.g., anxiety from somatization, hyperactivity from aggression) within each of the broadband syndromes. As an illustration of the model, data for 6 cognitive variables (e.g., global self-worth, causal attributions) are related to 6 psychopathology domains (e.g., aggression, depression) in a sample of 204 children. It is suggested that common features may be related to severity of psychopathology, whereas specific features may be more related to differentiation of psychopathology.

Child↗
PubMed1986

Statistical mixture decomposition as a method for type analysis of learning curves.

A method for type analysis of learning curves, based on the statistical mixture decomposition, is described. Some critical points in current data-analytic techniques are discussed. The mathematical rationale of the new method is outlined in a brief sketch. The possibilities of the method are documented by two examples. In the first study, done on simulated lata of a known structure (N = 200, 2 classes), it was possible to distinguish, with an average performance of 82%, between two types, and to reproduce their original curves. In the second study data from experiments in classical eye-lid conditioning in man were analysed (N = 80). The decomposition procedure resulted into the classification into four groups, with pronounced inter-class differences in the course of respective learning curves. The variety of class curves ranges from a group with only few CRs (C1, N = 26), through a group with an initial increase and final decrease in CR frequency (C2, N = 16), a group with an apparently biphasic course of CR frequency (C3, N = 20), to a group with a rapid increase of CR and then stable course of CR frequency (C4, N = 18). The results are consistent with earlier findings concerning the existence of distinct types of learning curves. The problem of interpretation is briefly discussed. The method can be applied principally to any problems, where different types of time development trends of an alternative response are to be distinguished.

Conditioning, Classical↗
PubMed1978

Application of the official AOAC chloresterol Method to a wide variety of food products.

This paper presents analytical data on the cholesterol content of selected consumer food products including some fats and oils. The cholesterol data are grouped by food products. To determine the reproducibility of cholesterol values, recovery data were obtained from samples of pure vegetable shortening spiked at 40 and 20 mg cholesterol (as cholesteryl palmitate)/100 g fat. Average recoveries were 97.1% and 95.5% with coefficients of variation of 1.27 and 3.24%, respectively.

Chemistry Techniques, Analytical↗
PubMed2004

Determination of trace elements in wines and classification according to their provenance.

Provenance and authenticity of wines can be recognized on the basis of typical mineral and trace element patterns by means of chemometric methods. Therefore analytical methods were developed for the determination of As, Be, Co, Cs, Ga, Li, Nb, Ni, Rb, Te, Ti, W, Y, and Zr as well as Mo, Cd, Sb, Tl, U, and the rare earth elements in wines by inductively coupled plasma mass spectrometry (ICP-MS). For low risk of contamination or loss of analyte as well as depletion of sample amount and an easy sample pretreatment, direct measurement of diluted wines was studied. The accuracy of the analytical results was proven by recovery experiments by method comparison with standard addition methods and measurement of digested wines. In addition to applying statistical methods for characterizing the precision of the methods, the uncertainty of the measurements was estimated. Results for the elements mentioned above and additional 16 elements (Al, B, Ba, Ca, Cr, Cu, Fe, Mn, Mg, P, Pb, Si, Sn, Sr, V, and Zn) were evaluated by data analytical methods. Due to a specific choice of the analytes for multivariate statistical investigation a prediction rate by cross validation of 88.6% could be achieved.

Aluminum↗