bluuebunny/crossref_metadata_2025_split huggingface dataset:
New enhancers for the chemiluminescent peroxidase catalysed chemiluminescent oxidation of pyrogallol and purpurogallin
Authors: Nozaki Osamu , Ji Xiaoying , Kricka Larry J. 
Published: May 2005

AbstractThe effects of various boronate compounds, 4‐biphenylboronic acid, 4‐bromobenzeneboronic acid, trans‐4‐(3‐propionic acid)phenylboronic acid and 4‐iodophenylboronic acid, on the horseradish peroxidase (HRP) catalysed chemiluminescent oxidation of pyrogallol and purpurogallin by peroxide were investigated. trans‐4‐(3‐Propionic acid)phenylboronic acid produced a 13.7‐fold enhancement in the peak light emission from the chemiluminescent HRP catalysed pyrogallol reaction (detection limit for HRP < 1.25 fmol). At low enhancer concentration a single peak of light emission was observed and as the enhancer concentration increased the time to peak light emission became progressively longer. The chemiluminescence showed two peaks at higher concentrations (> 54.3 μmol/L) and the individual peak times depended upon the concentration of the enhancer. All of the boronates enhanced peak light emission in the chemiluminescent HRP catalysed purpurogallin reaction. 4‐Biphenylboronic acid was the most effective and it enhanced peak light emission 314‐fold. The practical detection limit for HRP (Type VIA) using this enhancer was 4.18 pmol (peak emission at 20 minutes). This compound also enhanced peak light emission 232‐fold from a chemiluminescent HRP‐purpurogallin reaction in which molecular oxygen replaced peroxide as the oxidant.
Chemiluminescence response and adherence of neutrophils to cultured endothelial cells–influence of immunoglobulin G
Authors: Jonas Eleonore , Dwenger Alexander , Jonas Michael 
Published: May 2005

AbstractThe effect of different concentrations (0.87, 4.35, 8.7, 17.5, 25 and 35 mg/mL) of intravenous immunoglobulin G (Endobulin®) on neutrophil–endothelial cell interaction was studied using an in vitro model of human umbilical cord vein endothelial cells and human neutrophils. Because adherence of neutrophils to endothelial cells is an essential component in inflammatory processes leading to endothelial cell injury the influence of immunoglobulin G on adherence has been investigated.A second aim of the present study was to determine changes in chemiluminescence response of neutrophils during adherence to endothelial cells. Production of oxygen‐derived metabolites, measured by chemiluminescence response of neutrophils, decreased significantly in the presence of 8.7 mg immunoglobulin/mL test during coincubation of neutrophils and endothelial cells (p < 0.025). The adherence of neutrophils to endothelial cells was significantly decreased at a concentration of 8.7 mg immunoglobulin/mL test (p < 0.025).The present results indicate that this preparation of immunoglobulin G might exert a protective effect on neutrophil–endothelial cell interaction by decreasing adherence of neutrophils to endothelial cells and by scavenging reactive oxygen metabolites. Therefore, the current investigation points to a probable protective effect of immunoglobulin G in oxidative diseases, such as the adult respiratory distress syndrome.
Monitoring of spatial expression of firefly luciferase in transformed zebrafish
Authors: Mayerhofer R. , Araki K. , Szalay A. A. 
Published: May 2005

AbstractThe firefly luciferase gene attached to the cytomegalovirus promoter was transferred into zebrafish (Brachydanio rerio) by microinjection of fertilized eggs. Light emission could be monitored in vivo in eggs and throughout the early development of the fish by low‐light video‐image analysis. Gene expression was transient in most of the cases lasting for about 2 weeks. This gene cassette proved to be a very convenient and nondestructive transformation marker and the firefly luciferase gene appears to be a powerful tool for real‐time imaging of tissue‐specific gene expression in transgenic fish.
Expert system for knowledge‐based modelling of analytical laboratories as a tool for laboratory management
Authors: Klaessens Jo , Saris Theo , Vandeginste Bernard , Kateman Gerrit 
Published: May 2005

AbstractAn expert system (LABGEN) is presented for decision support in analytical laboratories by means of digital simulation. In an interactive manner, LABGEN constructs simulation models of laboratory organizations. It makes use of a database of model fragments and applies rules in order to prevent the user providing redundant information and to prevent inconsistent models being constructed. The models are written in the dedicated simulation language SIMULA. After compilation they can be used for simulation experiments. LABGEN can be applied to a wide range of laboratory organizations. An example of the application of LABGEN is presented.
A method for detecting potentially unreliable estimates when using the Burdick/Rayens model for estimating linear mixing proportions
Authors: Rayens William S. 
Published: May 2005

AbstractIn an earlier paper by Burdick and Rayens a model was developed which uses discriminant analysis to construct estimates of linear mixing proportions. In this paper a method is proposed for identifying potentially unreliable estimates when using the Burdick/Rayens model. It is also shown to be useful in detecting irregularities in the sample data. The methodology is based on the lengths of residual vectors and is demonstrated within the context of polychlorinated biphenyl mixtures.
Estimation of second‐order chemical kinetic parameters by using information‐based extended Kalman filtering
Authors: Barker Todd Q. , Brown Steven D. 
Published: May 2005

AbstractThe extended Kalman filter has been used to estimate initial reactant concentrations and rate constants for rate‐based chemical assays employing a second‐order chemical reaction. Application of first‐ and second‐order models to data permits reaction order identification by examining either the filter innovations or the evolution of the filter states. Because of non‐linearities in the second‐order kinetic model, repetitive filtering is necessary for convergence to reliable state estimates. Reduction of the filter calculation burden is investigated through the use of information‐based filter methods, and it is demonstrated that substantial decreases in the computational burden are possible without loss of filter accuracy. These decreases make possible the application of second‐order filters on large data sets, and they make real‐time filtering possible with a fast processor.
PLS regression methods
Authors: Höskuldsson Agnar 
Published: May 2005

AbstractIn this paper we develop the mathematical and statistical structure of PLS regression. We show the PLS regression algorithm and how it can be interpreted in model building. The basic mathematical principles that lie behind two block PLS are depicted. We also show the statistical aspects of the PLS method when it is used for model building. Finally we show the structure of the PLS decompositions of the data matrices involved.
Chemical information from electroanalytical data. Part 1—Determination of system parameters for quasi‐reversible electron transfer reactions from cyclic voltammetric test data and data for the reduction of cerium (IV) bis(octaethylporphyrinate)
Authors: Scharbert Bernd , Speiser Bernd 
Published: May 2005

AbstractValues of the peak potential, the peak current function and the peak potential difference are extracted from simulated cyclic voltammograms of a quasi‐reversible electron transfer reaction. Variations of the feature values are described by empirical functions of the model parameters α (transfer coefficient) and ψ′ (dimensionless form of the heterogeneous electron transfer rate constant ks) using multiple linear regression. These functions are used to determine the system parameters α and ks from test data sets of feature values. The predictive power of the features is discussed. It is shown that several features can be used simultaneously in the analysis. Also, α, ks, the formal potential E0 and the diffusion coefficient D can be estimated simultaneously. Experimental data from the metal‐centered one‐electron reduction of cerium (IV) bis(octaethylporphyrinate), Ce(OEP)2, are analyzed using the technique, and values of the system parameters for this electrochemical reaction are determined.
Program for processing of historical laboratory data based on fuzzy set theory as a tool for decision support
Authors: Klaessens J. , Van Schalkwijk J. , Cox P. , Bezemer R. , Vandeginste B. , Kateman G. 
Published: May 2005

AbstractA computer program (FEA) is presented for processing historical laboratory data. It performs on a list of sample entries stored in a laboratory information management system. Using an algorithm which is based on fuzzy set theory, FEA classifies the entries into a limited number of clusters called sample types. The classification is fully user‐defined. The program transforms the historical data into a representation which is more suitable for studying the performance of the laboratory or which can be used as preparation for a simulation project.
Can image analysis provide information useful in chemistry?
Authors: Geladi Paul , Esbensen Kim 
Published: May 2005

AbstractImages can contain chemical information and many chemical methods can generate image data. For an efficient extraction of chemical data from images, data analysis techniques are necessary. It is a great advantage to be able to work on multivariate images. Many imaging techniques allow the extraction of chemical information. Inorganic analytical chemistry seems to have the longest tradition here, but organic chemistry and biochemistry may soon be catching up. Also large data arrays from non‐imaging techniques can be combined with image analysis in a useful way, provided certain conditions are fulfilled.
Evolving factor analysis applied to flow injection analysis data
Authors: Gemperline Paul J. , Hamilton J. Craig 
Published: May 2005

AbstractEvolving factor analysis is used to estimate the concentration profiles and spectra of Bi3+ and the bismuth chloride complexes BiC12+ through BiCl formed by injection of bismuth perchlorate into a flowing stream of 1·0 mol 1−1 HCl. The estimated spectra compare favorably with previously published spectra of the complexes.
PLS response surface optimization: The CARSO procedure
Authors: Clementi Sergio , Cruciani Gabriele , Curti Gianluca , Skagerberg Bert 
Published: May 2005

AbstractThe paper presents a procedure to obtain response surfaces with non‐designed data. The method is based on PLS modelling of the expanded X‐matrix followed by transformation of the PLS loadings into polynomial coefficients and detection of the co‐ordinates of the best response within the experimental domain. The results are presented both graphically and numerically. The procedure is validated on an optimization study of the yield of an organic reaction.
Display aspects in hierarchical clustering
Authors: Henrion André , Henrion René , Henrion Günter 
Published: May 2005

AbstractUltrametric inter‐object distances found by hierarchical clustering may be used to generate and appropriate constellation of points in a plane. A configuration of points which reproduce the ultrametric distances in a low‐dimensional space as closely as possible can be found by Torgerson's method of multidimensional scaling. The resulting display supports the cognition of clusters very well, and for this purpose it seems to be superior to, for instance, the frequently applied principal components display. In certain situations dedrograms are expected to become simpler to interpret when such complementary ‘cluster display’ is also consulted. An example from analytical chemistry is presented.
Multicomponent determinations by a membrane‐discriminated gas phase analyzer and successive regression in the fiduciary region
Authors: Petersen Kaj , Lopez Jorge L. , Dasgupta Purnendu K. 
Published: May 2005

AbstractA membrane‐discriminated gas phase analyzer is proposed for multicomponent determinations. Nitrogen gas flows countercurrent through outer and inner channels in a tube‐in‐tube arrangement. The only communication between the two channels occurs through a 500 μm aperture covered by a porous PTFE membrane. A mixture of organic compounds (up to four components) is injected into the inner channel by a heated backflushed injector and the sample components diffusing into the outer channel are monitored by a flame ionization detector (FID). A calibration set, consisting of pure components, binary, ternary and quaternary mixtures (a total of 64 samples), provides the known data base: temporal profiles of the FID output as a function of sample composition. Although the overall response behavior is not a linearly additive function of individual analyte concentrations, the use of successive inverse multiple linear regression (while continually altering the choice of the calibration samples considered for the forward regression, on the basis of the most recent values of the predicted unknown sample composition) is shown to yield analytical results for unknown samples that are in good agreement with their true values.
Resolution of multicomponent fluorescent mixtures by analysis of the excitation–emission–frequency array
Authors: Burdick Donald S. , Tu Xin M. , McGown Linda B. , Millican David W. 
Published: May 2005

AbstractFluorescence lifetime provides a third independent dimension of information for the resolution of total luminescence spectra of multicomponent mixtures. The incorporation of this parameter into the excitation–emission matrix (EEM) by the phase modulation technique results in a three‐dimensional excitation–emission–frequency array (EEFA). Multicomponent analysis based on the three‐dimensional EEFA brings a qualitative change for the resolved spectra, i.e. individual spectra can be uniquely resolved, which is impossible with any two‐dimensional analysis. In this paper we present a method for analyzing the EEFA. We show mathematically that with the three‐dimensional analysis of the EEFA individual spectra and lifetimes can be obtained. Our algorithm is developed in mathematical detail and is demonstrated by its application to a two‐component mixture.
Enhancing the deconvolution of noisy chromatographic data by Jansson's method
Authors: Crilly Paul Benjamin 
Published: May 2005

AbstractIn previous papers Jansson's method was found to be successful at deconvolving severely overlapped gas chromatographic peaks. In the most recent paper the method was evaluated with respect to quantitative accuracy, peak area and retention time repeatability. The problems associated with deconvolving noisy data and some alternatives which can improve the ability of Jansson's method to deconvolve noisy data are discussed. These alternatives include presmoothing the data with a nine‐point, third‐order polynomial filter and data reblurring. This paper will test these methods on peaks with various degrees of resolution and signal‐to‐noise ratios.
A new approach to confirmation by infrared spectrometry
Authors: De Ruig W. G. , Weseman J. M. 
Published: May 2005

AbstractIn the series of analytical techniques for identification of chemical substances, infrared spectrometry presents by far the highest information content. However, the information is most complicated too. It concerns a multitude of band positions, band intensities and band shapes, which, moreover, can be disturbed by matrix and other effects. The high redundancy, however, allows conclusions to be made by a qualitative, subjective procedure.IR is often used to prove the equality between a sample and a reference material, e.g. in quality control of a production process. In forensic control, the question to be answered is mostly not to prove equality, but whether or not the presence of a compound in a sample, e.g. a drug, can be proved. Moreover, testing has to be performed according to objective rules.To fulfil these requirements, a new retrieval algorithm, the ‘Adequate Peaks Search’, is presented. It concerns representing the reference spectra by sets of adequate peak positions and the sample spectrum by a set of all peak positions, whereafter the cross‐sections of the sample set and the reference sets are determined. The concept ‘adequate peak’ is defined and criteria have been formulated to evaluate the results into a positive (presence of the analyte is proved) or negative (presence is not proved) conclusion.The detection limit when the Adequate Peaks Search (APS) method was applied was four to seven times lower than that attained by a number of experts.
An approach to obtaining an optimal design in the non‐linear least squares determination of binding parameters in a complex biochemical system
Authors: Crisponi Guido , Nurchi Valeria , Ganadu M. Luisa 
Published: May 2005

AbstractThe design of an experiment for the determination of binding parameters in the association between a ligand and a macromolecule with two groups of non‐interacting binding sites is proposed. In the Gauss–Newton non‐linear least squares treatment the standard deviation of each parameter is given as the product of two terms: one depending on the experimental error and the other, the diagonal element of the dispersion matrix, depending only on the independent variables of the system. In order to reach an optimal experimental design, these diagonal elements of the information matrix have to be minimized. In our approach this is achieved by searching those values of the independent variable which maximize the determinant of the information matrix. Furthermore, the limits of validity of the model are deduced from an analysis of the diagonal elements of the information matrix obtained under optimal conditions.
Target factor analysis: UV spectrophotometry for the simultaneous determination of six amino acids
Authors: Zhongxiao Pan , Siqing Xia , Shengzhu Si , Maosen Zhang , Leming Shi , Xinan Liu 
Published: May 2005

AbstractThe UV spectra of mixture solutions consisting of tyrosine, tryptophane, phenylalanine, cystine, histidine and 3,4‐dihydroxyl phenylalanine have been measured. The numbers, identities and concentrations of the amino acids in the mixtures have been determined successfully using target factor analysis. The effects of the wavelength range and the selected sampling interval on the results are discussed. Twenty‐five synthetic mixture samples have been analysed successfully. The average recoveries are 98.9 for Tyr, 96.5 for Trp, 105.6 for Phe, 98.1 for Cys, 98.9 for His and 106.4 for Di‐phe. The results obtained are in good agreement with those obtained by the Kalman filter method.
Use of the Wronskian determinant in the study of multicomponent systems
Authors: Koinis S. P. , Tsatsas A. T. , Katakis D. F. 
Published: May 2005

AbstractThe use of Wronskian determinants in the study of multicomponent systems is proposed. The general theory is presented and applied to the spectrophotometric determination of the number of linearly independent components–absorbers. A detailed study of a two‐component system is presented and analysed. Numerical methods for smoothing and differentiation of digitized spectra via cubic splines are used.
The use of a ratio method as an alternative to constrained deconvolution
Authors: Crilly Paul Benjamin 
Published: May 2005

AbstractThis paper will consider the use of an iterative ratio technique called Gold's ratio method as an alternative to iterative constrained deconvolution methods for the restoration of overlapped and noisy chromatograpic peaks. The study will consist of first describing the technique and then evaluating its performance with respect to Jansson's deconvolution procedure. A Hewlett‐Packard 5890A gas chromatograph will be used to generate most of the test data. The evaluation criteria will include convergence rates, peak area errors and variances, retention time variances and noise performance.
Rank‐order analysis for robust multiresponse, multiblock comparisons: Evaluation of herbicide interactions
Authors: Duewer David Lee , Clark Robert D. 
Published: May 2005

AbstractStudies of interactions among bioactive compounds are often difficult to interpret unambiguously. A priori assumptions about the nature of such interactions can seriously distort analysis of the data. By applying a rank order analysis appropriate to the naturally ordinal scale of response to xenobiotic insult, several co‐herbicides were successfully identified from among numerous candidates in an experiment involving multiple blocks, rates and species. Moreover, underlying herbicide interactions were substantiated and identified which were not apparent by more traditional parametric analysis.
Comparison of measurement methods based on a model for the error structure
Authors: Nilsson Göran 
Published: May 2005

AbstractComparison of methods is a technique often used for investigation of systematic errors of measurement methods. As concerns the design and analysis of such comparisons, much variety of opinion and practice exists. In one approach a few specimens are measured several times by different operators in different laboratories (reproducibility conditions) and in another approach several specimens are measured on one or a few occasions by one operator in the same laboratory (repeatability conditions). In this paper a model for the error structure of measurements is formulated and it is emphasized that one has to distinguish between two types of systematic errors: the first type depends only on the level of the measured quantity and the second type is specific for the separate specimens. On the basis of this model the information which can be obtained from the different designs of method comparisons is discussed. A new approach for the analysis of method comparisons with many specimens is also proposed.
Principal variations in the chemical composition of peat: Predictive peat scales based on multivariate strategies
Authors: Hämäläinen Markku , Albano Christer 
Published: May 2005

AbstractThe principal properties, here called the ρ‐scales, of peat have been calculated on the basis of chemical analysis. The scales were derived from quantitative contents of carbohydrates, Klason lignin, amino acids, amino sugars and conventional chemical peat measurements. The variation in the chemical parameters was compressed using principal component analysis (PCA). Partial least squares (PLS) regression was used for prediction of botanical, microbial, physical and dewatering data. A rapid estimation of the scales has been made from near‐infrared (NIR) spectroscopy and offers, indirectly, rapidly obtainable, chemically interpretable, biological information. A reduced scale based on carbohydrate data was also tested. The ρ‐scales offer an interface between different areas of peat research. Strategies are outlined for the selection of a subset of chemical measurements among the variables used for characterization. A multivariate strategy based on these ideas is discussed.