bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design of coupled reactions for simplification of bioluminescence analysis
Authors: Brolin S. E. , Naeser P. , Wettermark G. 
Published: May 2005

AbstractLuminescence analysis may be applied to many substances by arranging a prior reaction producing a species entering the light‐emitting reaction. Under favourable conditions the two consecutive reactions are carried out simultaneously as a one‐step procedure. In a bioluminescence assay, luciferase stability is frequently a problem, making it desirable to develop analytical schemes where the analytical response becomes largely independent of any impaired luciferase activity. The value of maximal emission or an approached steady‐state level is a convenient and usually well‐defined analytical parameter. When recording this level it is important to design the participating reactions in a way that compensates for changes in luciferase activity.
Measurement of estrone‐3‐glucuronide and pregnanediol‐3α‐glucuronide in early morning urine samples to monitor ovarian function
Authors: Magini A. , Pinzani P. , Bolelli G. F. , Bassi F. , Salerno R. , Messeri G. , Pazzagli M. 
Published: May 2005

AbstractThe determination of the concentration of estrone‐3‐glucuronide and pregnanediol‐3α‐glucuronide has been performed by a chemiluminescent immunoassay in early morning urine samples of 14 normal menstruating women and 11 women affected by luteal phase defect. The early morning urine samples were daily collected for an entire menstrual cycle. We have employed a timed and measured volume collection procedure as correction factor. The integrated values of the hormonal data in definite time intervals were used to create a nomogram. By means of this method, it was possible to completely separate normal from luteal insufficiency subjects and to distinguish two different types of luteal phase defects. Moreover, the same approach was applied to the study of the role and the frequency of luteal phase defect in 15 patients affected by habitual abortion and in 17 premenopausal women who had undergone quadrantectomy for T1a No Mo breast cancer. A luteal phase defect was detected in nine of the aborting patients (60%) and in eight women affected by breast cancer (47%). Finally estrone‐3‐glucuronide was measured in early morning urine samples of 96 prepubertal and pubertal girls in different pubertal stages and in one patient affected by precocious puberty, before and during an agonist GnRH treatment. The urinary test of ovarian function seems to be suitable for diagnostic purposes and for clinical studies.
Methodological evaluation of a new chemiluminescence immunoassay for thyrotropin using acridinium ester‐labelled antibody
Authors: Zucchelli G. C. , Pilo A. , Masini S. , Chiesa M. R. , Masi A. 
Published: May 2005

AbstractA recently available immunochemiluminometric assay (ICMA) for TSH developed by Ciba Corning Corp. has been evaluated. This system (Magic Lite) uses an acridinium‐ester‐labelled antibody and magnetizable particle for bound‐free separation. In each assay only two calibrators are carried out and used to re‐scale a manufacturer‐generated curve stored in the memory of the luminometer. The precision of the response (RLU) estimated by all duplicates of 14 runs was about 4% for responses >12,000 RLU (corresponding to a concentration interval 0.7–113 μlU/ml) and worsened in the lower range (up to 10% CV); the sensitivity, computed from the mean within‐assay precision profile, was 0.028 μlU/ml; the between‐assay precision ranged from 4.6 to 13.1 CV%. Regression analysis of ICMA results (y) against consensus values of Behring IRMA (x) on 15 QC sera assayed in an inter‐laboratory survey (concentration range 1–30 μlU/ml) gave y = −0.003 + 0.98x indicating a good agreement of the two techniques. Similar conclusions have been derived from the comparison of the ICMA results (y) in the low TSH concentration range (< 1 μlU/ml) against the IRMA Boots Celltech (x) on 80 patient samples (y = 0.04 + 1.04x).
Novel monomeric luciferase enzymes as tools to study plant gene regulation in vivo
Authors: Olsson Olof , Nilsson Ove , Koncz Csaba 
Published: May 2005

AbstractTaking advantage of a specially constructed vector, luciferase LuxA and LuxB subunits were connected in frame to different amino acid linkers to reproduce a series of monomeric luciferase enzymes. A comparison of their activities in E. coli cells demonstrated that the length of the linkers positively affected activity. One luciferase fusion gene was expressed in plant cells, and we showed that this gene activity could be monitored directly without destructive sampling.
Excited carbonyl formation in the combination and disproportionation of free radicals
Authors: De La Fuente U. J. R. , Lissi G. E. A. 
Published: May 2005

AbstractThe pyrolyisis of di‐tert‐butyl peroxyoxalate in the presence of para‐substituted benzaldehydes produces almost quantitatively the corresponding p,p′‐disubstituted benzils. The formation of these products is accompanied by chemiluminescence arising from excited triplets. From the quantum yield of excited triplet generation and the rate constants for the triplet photocleavage it is possible to obtain the change in Gibbs free energy associated with triplet formation. The values obtained are −5.6, −5.7 and −8.1 kcal/mol for benzil, p,p′‐dimethylbenzil and p,p′‐dimethoxybenzil, respectively.The pyrolysis of di‐tert‐butyl peroxyoxalate in the presence of isopropanol or benzoin leads to the formation of acetone and benzil. These products are generated in disproportionation processes involving the α‐hydroxy radical produced by hydrogen abstraction. The luminescence observed in these reactions constitutes the first experimental indication of excited species generation in the disproportionation of uncorrelated free radicals.
Chemiluminescence of human bloodstream monocytes and neutrophils: An unusual oxidant(s) generated by monocytes during the respiratory burst
Authors: Davies Bernard , Edwards Steven W. 
Published: May 2005

AbstractMaximal rates of O and H2O2 production by human bloodstream monocytes activated during the respiratory burst by phorbol ester were only about 10% of those of neutrophils. Furthermore, monocytes possess only about 5% of the myeloperoxidase activity of neutrophils and so can only produce low levels of HOCI and related compounds. These combined reductions in O generating ability and lower myeloperoxidase levels result in low luminol chemiluminescence stimulated during the respiratory burst of monocytes. However, although monocytes generate much lower levels of O and H2O2 than neutrophils, these cells produce comparable rates of PMA‐stimulated lucigenin chemiluminescence. Hence, this assay does not accurately reflect the production of either of these two oxidants by activated phagocytes, and further lucigenin must react with some other oxidant(s) via a process which leads to photon emission. This oxidant(s) is not O, H2O2, · OH, 1O2 or NO, but is derived from O generated during the respiratory burst and is generated in greater quantities by activated monocytes compared with neutrophils. Thus, lucigenin chemiluminescence is an indirect measure of superoxide release.
Flow injection assays with chemiluminescence and bioluminescence detection — A review
Authors: Lewis Simon W. , Price David , Worsfold Paul J. 
Published: May 2005

AbstractThis paper reviews publicaions that combine the technique of flow injection (FI) with chemiluminescence (CL) and bioluminescence (BL) detection, from the earliest papers in 1979/80 to mid‐1992, and refers exclusively to reactions occurring in solution. Airsegmented systems and liquid chromatography with CL detection are not considered unless FI has been used to pre‐optimize the system. The applications have been categorized in terms of the type of CL reaction; there are separate entries for luminol, peroxyoxalate, other CL reactions and BL reactions. Each of the four sections includes a table of applications that lists the analyte, the nature of the reaction, the sample matrix and the limit of detection.
Assay of antioxidants by the quenching of the anthracene‐sensitized electrochemiluminescence
Authors: Chmura Janusz , Slawiński Janusz 
Published: May 2005

AbstractThe kinetic and spectral characteristics (chemiluminescence and fluorescence spectra) of ultraweak luminescence accompanying the electrolysis of a sodium citrate–methanol–dissolved O2 solution and its application for the determination of antioxidants were examined. The energy transfer‐assisted luminescence sensitized by anthracene provides a fast and sensitive assay for the determination of the concentration and kinetic parameters of antioxidants and free radical scavengers.
Applications of low‐light imaging to life sciences
Authors: Nicolas J. C. 
Published: May 2005

AbstractPhoton imaging is a new technique for the quantitative analysis of bioluminescence and chemiluminescence and can be performed both at the macro and micro levels. The high sensitivity and spatial resolution of photon‐counting cameras have resulted in the development of new applications in the life sciences.At the macro level, imaging is a valuable tool for the rapid identification of biological samples emitting long‐lasting glows in assays using microtitre plates or filter formats (immunoassays, DNA probes, phagocytosis, gene expression, metabolite and drug analysis) and also for in vivo studies of promoter activity. At the micro level, low‐light imaging can be used for analysing multiple analytes on micro sensors and for advanced cell analysis (immunocytology, in situ hybridization, identification of cells or tissues expressing the luciferase gene, intracellular or intercellular protein traffic, metabolite analysis and imaging of Ca2+ flux and phosphorylation reactions).Two‐dimensional photon‐counting instrumentation is a versatile and powerful research tool for imaging and is complementary to conventional luminometers. The main applications to the life sciences involve many types of luminescence assays and can be performed on multiple samples in standard and non‐standard formats. Photon‐counting coupled to imaging is very helpful in selecting microorganisms or cells expressing bioluminescent genes. Measurements can be made in vitro and in vivo with a sensitivity comparable to that of phototube luminometers.
Effect of sulphite on the oxidative metabolism of human neutrophils: Studies with lucigenin‐ and luminol‐dependent chemiluminescence
Authors: Mishra Anil , Dayal Niru , Beck‐Speier Ingrid 
Published: May 2005

AbstractTo assess the effect of sulphite on the oxidative metabolism of human neutrophils, chemiluminescence (CL) measurements were performed using lucigenin and luminol as chemiluminigenic probes. Lucigenin‐dependent CL was used for measuring superoxide anion (O) production, and luminol‐dependent CL was used for determination of myeloperoxidase (MPO)‐connected processes. With sulphite concentrations of 0.01 to 1 mmol/L, resting neutrophils showed an up to sixfold increase of lucigenin‐dependent CL, but only a 1.9‐fold increase of luminol‐dependent CL. Subsequent stimulation of sulphite‐treated neutrophils with phorbol myristate acetate (PMA) (soluble stimulant) or zymosan (particulate stimulant) resulted in an additional significant increase of lucigenin‐dependent CL compared to stimulated control cells, whereas luminol‐dependent CL increased slightly by 0.01 mmol/L sulphite and decreased then continuously. Sulphite concentrations above 1 mmol/L decreased both lucigenin‐ and luminol‐dependent CL of resting and PMA‐ or zymosan‐stimulated neutrophils. Lucigenin‐dependent CL of sulphite‐treated and subsequently stimulated neutrophils was strongly inhibited by extracellularly added superoxide dismutase, whereas luminol‐dependent CL was markedly reduced by the MPO inhibitor azide. The intracellular activity of MPO in neutrophils stimulated with PMA in the presence of sulphite (2 mmol/L) was reduced by 55%. Sulphite (0.1 mmol/L) also inhibited strongly the activity of MPO in a cell‐free system. These results indicate that micromolar concentrations of sulphite exert a stimulating effect on the O production of neutrophils extracellularly, but have an inhibitory effect on MPO‐catalysed reactions intracellularly.
Formation of active bacterial luciferase between interspecific subunits in vivo
Authors: Almashanu S. , Tuby A. , Hadar R. , Einy R. , Kuhn J. 
Published: May 2005

AbstractInterspecific complementation between luxAs and luxBs from Vibrio harveyi, Vibrio fischeri, Photobacterium leiognathi and Xenorhabdus luminescens was examined in vivo. The individual genes from these species were cloned on different compatible plasmids or amplified by PCR and brought together to yield cis combinations without extraneous DNA. The beta subunits from V. harvayi and X. luminescens form active enzyme only with alpha subunits from one of these species. All other combinations yield active enzymes. The lack of activity of the V. harveyi and X. luminescens beta subunits with the alpha subunits from V. fischeri and P. leiognathi results from a lack of association. This was shown by in vivo competition in which these beta subunits were overproduced in comparison with the beta and alpha of V. fisheri. No reduction in light was found. Overall, the in vivo results parallel those found in vitro using isolated denatured subunits and renaturation by removal of the denaturant.
Fast and sensitive chemiluminescence determination of H2O2 concentration in stimulated human neutrophils
Authors: Mueller S. , Arnhold J. 
Published: May 2005

AbstractA fast and sensitive chemiluminescence assay for the determination of H2O2 in stimulated neutrophils without the use of enzymes was developed. The method is based on the oxidation of luminol by hypochlorous acid. The chemiluminescence of this reaction is highly dependent on the concentration of hydrogen peroxide.Changes in H2O2 concentration in PMA‐stimulated neutrophils were followed by injection of NaOCI to cell suspension at different times after cell stimulation. The short integration time of 2 s permits calculation of actual concentrations of H2O2 without influence of H2O2 decomposition by cellular enzymes or newly produced H2O2 due to dismutation of superoxide anion radicals. Concentrations of H2O2 were diminished by catalase and enhanced by sodium azide owing to inhibition of cellular catalase and myeloperoxidase. Changes in H2O2 concentration upon stimulation could be observed at 3000 cell/mL.
Notes on the history and nature of partial least squares (PLS) modelling
Authors: Geladi Paul 
Published: May 2005

AbstractThe growing awareness of the need for non‐deterministic and distribution‐free (soft) models combined with an iterative algorithm for finding latent variables led to the construction of partial least squares models. There have been separate developments in the humanistic and the natural sciences, with stress on different aspects and a different terminology. The historical development is described and some key topics are explained.
Dried grass silage analysis by NIR reflectance spectroscopy—A Comparison of stepwise multiple linear and principal component techniques for calibration development on raw and transformed spectral data
Authors: Downey Gerard , Robert Paul , Bertrand Dominique , Devaux Marie‐Francoise 
Published: May 2005

AbstractCalibrations to predict crude protein (CP) and in vitro dry matter digestibility (IVDMD) in dried grass silage from reflectance data collected at 19 wavelengths on an InfraAlyzer 400R have been developed using stepwise multiple linear (SML) and principal component (PC) regression techniques. A direct comparison of the efficacy of each multivariate technique in this applications has been possible by using identical calibration development and evaluation sample sets. The effect of two data transformation steps prior to PC regression was also investigated. PC regression of raw reflectance data yielded no significant improvement in the standard errors of prediction (SEP) for CP and IVDMD over those obtained by SMLR, viz. 0·61 vs 0·63 and 2·9 vs 3·0 respectively. Computation time for development and evaluation of the PC regression equation was less than for selection of the best SMLR equation, and PCR equations may be more robust. Data transformation to reduce granularity effects prior to PCR did not produce any improvement in predictive accuracy for either IVDMD or CP.
Mixture analysis using factor analysis. II: Self‐modeling curve resolution
Authors: Hamilton J. Craig , Gemperline Paul J. 
Published: May 2005

AbstractOne of the major applications of factor analysis in the chemical literature, self‐modeling curve resolution (SMCR), is covered in this review, including a historical account of the methods derived from Lawton and Sylvestre's original method. Papers treating the theory or applications of SMCR are included. Qualitative and quantitative applications are described where appropriate.
Residual bilinearization. Part 1: Theory and algorithms
Authors: Öhman Jerker , Geladi Paul , Wold Svante 
Published: May 2005

AbstractWhen using hyphenated methods in analytical chemistry, the data obtained for each sample are given as a matrix. When a regression equation is set up between an unknown sample (a matrix) and a calibration set (a stack of matrices), the residual is a matrix R.The regression equation is usually solved by minimizing the sum of squares of R. If the sample contains some constituent not calibrated for, this approach is not valid. In this paper an algorithm is presented which partitions R into one matrix of low rank corresponding to the unknown constituents, and one random noise matrix to which the least squares restrictions are applied. Properties and possible applications of the algorithm are also discussed.In Part 2 of this work an example from HPLC with diode array detection is presented and the results are compared with generalized rank annihilation factor analysis (GRAFA).
A class‐modelling technique based on potential functions
Authors: Forina Michele , Armanino Carla , Leardi Riccardo , Drava Giuliana 
Published: May 2005

AbstractA probabilistic and distribution‐free class‐modelling technique is developed from potential function discriminant analysis. In the multidimensional space of variables the class boundary is built either by the sample percentile of the probability density estimated by means of potential functions, or by the estimate of the ‘equivalent’ determinant of the variance–covariance matrix. The equivalent determinant is that of a hypothetical multivariate normal distribution whose mean probability density was obtained by potential functions. The bases of this modelling rule are evaluated by means of Monte Carlo experiments. The results on four datasets are used to measure the performances of this method, which equal and sometimes exceed the performances of parametric class‐modelling methods based on linear and quadratic discriminant analysis which were used for comparison.
The effect of mean centering on prediction in multivariate calibration
Authors: Seasholtz Mary Beth , Kowalski Bruce R. 
Published: May 2005

AbstractTraditionally, one form of preprocessing in multivariate calibration methods such as principal component regression and partial least squares is mean centering the independent variables (responses) and the dependent variables (concentrations). However, upon examination of the statistical issue of error propagation in multivariate calibration, it was found that mean centering is not advised for some data structures. In this paper it is shown that for response data which (i) vary linearly with concentration, (ii) have no baseline (when there is a component with a non‐zero response that does not change in concentration) and (iii) have no closure in the concentrations (for each sample the concentrations of all components add to a constant, e.g. 100%) it is better not to mean center the calibration data. That is, the prediction errors as evaluated by a root mean square error statistic will be smaller for a model made with the raw data than a model made with mean‐centered data. With simulated data relative improvements ranging from 1% to 13% were observed depending on the amount of error in the calibration concentrations and responses.
Compression of nth‐order data arrays by B‐splines. Part 1: Theory
Authors: Alsberg Bjørn K. , Kvalheim Olav M. 
Published: May 2005

AbstractFor efficient handling of very large data arrays, pretreatment by compression is mandatory. In the present paper B‐spline methods are described as good candidates for such data array compression. The mathematical relation between the maximum entropy method for compression of data tables and the B‐spline of zeroth degree is described together with the generalization of B‐spline compression to nth‐order data array tables in matrix and tensor algebra.
Body diagonalization of core matrices in three‐way principal components analysis: Theoretical bounds and simulation
Authors: Henrion René 
Published: May 2005

AbstractIn contrast with conventional PCA, a direct superposition and joint interpretation of loading plots is not possible in three‐way PCA, since there may be data variance which is described by unequal components of different modes. The contributions to variance of all possible combinations of components are described in the core matrix. Body diagonalization, which is achieved by appropriate rotation of component matrices, is an essential tool for simplifying the core matrix structure. The maximum degree of body diagonality which may be obtained from such transformations is analysed from both the mathematical and simulation viewpoints. It is shown that, at least in the average case, high degrees can be expected, which makes the procedure reasonable for many practical applications. Furthermore, simulation as well as theoretical derivation show that the success of body diagonality depends on the so‐called polarity of the core array. The methodology is illustrated by a three‐way data example from environmental chemistry.
Effect of standardization on fragment‐based measures of structural similarity
Authors: Bath Peter A. , Morris Carol A. , Willett Peter 
Published: May 2005

AbstractSubstructural fragment occurrence data are widely used as the basis for measures of inter‐molecular structural similarity. This paper investigates the effect of standardization on the effectiveness of such measures using eight data sets for which both structural and biological activity data are available. Eight different standardization methods are studied and it is shown that there is no significant difference in the effectivenesses of the various methods; accordingly, any of them can be used for the calculation of intermolecular structural similarity.
Identifying significant effects in fractional factorial experiments
Authors: Langsrud Øyvind , Ellekjaer Marit Risberg , Naes Tormod 
Published: May 2005

AbstractThis paper presents a method for identifying significant effects in fractional factorial designs. The method is based on comparing functions of the estimated effects with a scale invariant reference distribution. The method is illustrated and compared with alternative techniques on a dataset from processed cheese production. The method corresponded well to other methods (probability plotting and Bayes plot) that do not make use of error estimates. These methods were better than F‐tests with few (two or four) degrees of freedom for error.