bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new approach for analysis of chemiluminescent kinetics of activated phagocytes in blood
Authors: Magrisso Moni J. , Bechev Blagovest G. , Bochev Petyo G. , Markova Vania I. , Alexandrova Margarita L. 
Published: May 2005

AbstractLuminol chemiluminescence (LCL) is a simple, sensitive and time‐saving tool to elucidate the oxidative activity of polymorphonuclear leukocytes (PMNL). In this study, a new approach for analysing the LCL kinetics, recorded from stimulated PMNL, and for a more accurate elucidation of their functional state, is proposed. This approach is based on the proposal that the LCL kinetics of stimulated PMNL is a result of time‐probabilistic nature of the processes, leading to light emission. On this basis the LCL response was described by the parameters of a Poisson‐type distribution.Relationships between these parameters and some factors influencing LCL kinetics (number of PMNL and erythrocytes, temperature, stirring) were investigated. Their development in time was different. It was suggested, that the two phases of the model LCL response were connected with extracellular and intracellular LCL. The terms and the advantages of this approach for analysis of phagocyte oxidative capacity are discussed.
Ticlopidine augments luminol‐dependent chemiluminescence in human neutrophils
Authors: Bednar Martin M. , Dooley Richard H. , Tapanes Ricardo , Lublin Jennifer C. , Gross Cordell E. 
Published: May 2005

AbstractNeutrophils contribute to the pathophysiology of various ischaemic states. Since many agents thought to be antiplatelet have also been shown to affect neutrophil function, it was of interest to examine the effect of ticlopidine (250 mg, p.o., b.i.d. for three doses), an antiplatelet agent, on fMLP (formyl‐methionyl‐leucyl‐phenylalanine) stimulated neutrophil aggregation and luminol‐dependent chemiluminescence in whole blood. Neutrophil aggregation did not significantly change from baseline values during ticlopidine administration. However, luminol‐dependent chemiluminescence, an index of respiratory burst metabolism, was noted to be markedly increased during ticlopidine administration. Two hours following the final dose of ticlopidine, the chemiluminescent response (mean ± SEM, n = 5) was significantly increased from 6.27 ± 1.88 to 12.66 ± 2.19 units (p < 0.05). A return to baseline (6.68 ± 2.24 units) five days following the administration of ticlopidine was noted. It is concluded from this study that the acute oral administration of ticlopidine may affect neutrophil function as demonstrated by the significant increase in stimulated luminol‐dependent chemiluminescence.
Electrogenerated chemiluminescence from violanthrone
Authors: Quickenden T. I. , Hansongnern K. 
Published: May 2005

AbstractViolanthrone, an emitter of exceptionally bright chemiluminescence, was examined in dimethylformamide solution to determine whether it also emits particularly bright electrogenerated chemiluminescence (ECL). The ECL measurements were carried out using a cycled potential which was applied to platinum electrodes. At the maximum sweep rate of 80 Vs−1 available, the intensity of the violanthrone ECL was still increasing with sweep rate and was c. 56% of that from rubrene, a bright, commonly used emitter of ECL. Furthermore, assuming that the emission arises from radical anioncation recombination, the sweep rate dependence showed that the least stable radical ion (probably the cation) decays with a half‐life shorter than 0.2s.
The development of Luminomaster™, a fully automated chemiluminescent enzyme immunoassay system
Authors: Ikegami Takashi , Yamamoto Masatoshi , Sekiya Koichi , Sato Yoshihiro , Saito Yukio , Maeda Masako , Tsuji Akio 
Published: May 2005

AbstractWe have developed a fully automated discrete chemiluminescent heterogeneous enzyme immunoassay system called Luminomaster™. The characteristics of this analyser are: 120 test/h throughput, 14 test menu, wide dynamic range, automated sample dilution, automatic retest, communication with a host central processing unit (CPU) and connection with sample transfer system.
A comparative study of PCR product detection and quantitation by electrochemiluminescence and fluorescence
Authors: Yu Hao , Bruno John G. , Cheng Tu‐chen , Calomiris Jon J. , Goode Michael T. , Gatto‐Menking Deborah L. 
Published: May 2005

AbstractAmplification and detection of target DNA sequences are made possible in a polymerase chain reaction (PCR) by using a mixture of biotinylated and ruthenium(II) trisbipyridal (Ru(bpy)32+)‐end‐labelled primers. In this way, biotin for capture and Ru(bpy)32+ for detection are directly incorporated into the PCR product obviating subsequent probe hybridization. PCR of a bacterial DNA template from Alteromonas species strain JD6.5 using a cocktail of biotin‐ and Ru(bpy)32+‐labelled primers amplified a 1 kilobase region. Serial dilution of PCR product followed by magnetic separation with Streptavidin (SA)‐coated magnetic beads and an electrochemiluminescence (ECL) assay using the semi‐automated QPCR System 5000 demonstrated sensitive (pg range) DNA detection. ECL assay of probe hybridization to a human immunodeficiency virus (HIV) sequence also produced pg level sensitivity. Quantitative DNA determination by ECL assay correlated well with visual detection of DNA in electrophoretic gels. However, DNA detection by ECL assay was 10 to 100 times more sensitive than conventional ethidium bromide staining. The combination of DNA‐based magnetic separation with ECL assay provides a very sensitive and rapid method of quantitating DNA which, owing to its rapid and facile nature, may have many applications in the research, environmental monitoring, industrial and clinical fields.
Comparison of seven bio‐ and chemiluminescent reagents for in situ detection of antigens and nucleic acids
Authors: Lamarcq L. , Lorimier P. , Negoescu A. , Labat‐Moleur F. , Durrant I. , Brambilla E. 
Published: May 2005

AbstractBio‐ and chemiluminescence have proved sensitive enough to compete with chromogenic and radioisotopic tracers for in situ detection. However, they must also provide a discriminant morphological analysis of the specific signal. We have tested seven bio‐or chemiluminescent reagents for tissue antigen and nucleic acid detection by immunocytochemistry (ICC) or in situ hybridization (ISH). They were based on luminescent detection of peroxidase, aikaline phosphatase, β‐galactosidase or xanthine oxidase. We also explored whether high molecular weight polymers could increase the spatial definition of the photon emission.An ICCD camera was used to collect the light signal provided by immunolabelling of endothelial cells and by ISH of human papilloma virus on cell smears.Among the enzyme‐luminescent substrate combinations tested, the enhanced luminol chemiluminescence (ECL) gave the best resolution of the specific signal. The other systems were mainly hampered by a high diffusion of the reaction product over the tissue section. Unfortunately, in this case, the high molecular weight polymers tested were inefficient. However, the addition of polyvinylalcohol (PVA) or polyvinylpyrrolidone (PVP) significantly improved respectively the definition and intensity of ECL photon emission. We demonstrate that chemiluminescence gives a morphological resolution allowing histological examination. The extension of this new application, now depends on physicochemical adaptation of chemiluminescent reagents to the constraints of tissue detection.
Action of phenolic antioxidants on various active oxygen species
Authors: Cynshi Osamu , Takashima Yoshiaki , Katoh Yoshiaki , Tamura Kunio , Sato Mitsuo , Fujita Yuzo 
Published: May 2005

AbstractThe action of phenolic antioxidants, such as probucol, on various active oxygen species was investigated using luminol chemiluminescence and spin trapping with 5,5‐dimethyl‐1‐pyrroline‐N‐oxide (DMPO). The various active oxygen species, including hydroxyl radicals (Fenton reaction), superoxide anions, singlet oxygen and hypochlorite ions were examined with phenolic antioxidants under aqueous and nonaqueous conditions. Probucol showed a quenching effect on both superoxide anions and hypochlorite ions in nonaqueous solution. However, it had no effect on hydroxyl radicals. α‐Tocopherol, a natural phenolic antioxidant, showed a stronger quenching effect on superoxide anions and hypochlorite ions than probucol, and quenched hydroxyl radicals in nonaqueous solution. Furthermore, Trolox showed a quenching effect on all active oxygen species in both aqueous and nonaqueous solution. The antioxidants were studied under comparable conditions in a series of test systems and the reactivity profiles depicted as ‘radar charts’ which are helpful for characterizing antioxidant action.
Light from maillard reaction: Photon counting, emission spectrum, photography and visual perception
Authors: Wondrak Georg , Pier Thomas , Tressl Roland 
Published: May 2005

AbstractSeveral authors have reported on high‐sensitivity measurement of oxygen‐dependent low‐level chemiluminescence (CL) from Maillard reactions (MR), i.e. nonenzymatic amino‐carbonyl reactions between reducing sugars and amino acids (also referred to as nonenzymatic browning). Here we report for the first time, that light from Maillard reactions can be seen by the human eye and also can be photographed. In parallel with visual perception and photography CL was monitored by means of a CL‐detection programme of a liquid scintillation counter (LSC, single photon rate counting). CL emission spectrum was recorded by a monochromator‐microchannel plate photomultiplier arrangement. CL intensity from reaction of 6‐aminocaproic acid with D‐ribose (200 mg each) in 5 mL H2O at pH 11 at 95°C was high enough for visual perception after adaptation to absolute darkness. Reaction in dimethylsulphoxide (DMSO) exhibited strongly enhanced CL (10 mg each in 5 mL were sufficient for visual detection) and could be photographed (15 minutes' exposure, ASA 6400); all characteristics of Maillard specific CL (O2‐dependence, no CL from nonreducing sugars, inhibition by sulphur compounds) remained. Visual detection of CL and measurement by LSC were in full concordance. The CL emission spectrum showed two broad peaks at around 500 nm and 695 nm. Fluorescence emission of the brown reaction mixture matched the bluegreen part of the CL emission spectrum. Emission of visible light during Maillard reactions may partly originate from oxygen‐dependent generation of excited states and energy transfer to simultaneously formed fluorescent products of the browning reaction.
Enumeration of phagocytosed Staphylococcus aureus inside cells of the mouse macrophage cell line J774 by bioluminescence, fluorescence and viable counting techniques
Authors: Sunderland Julie , Brenwald Nigel , Smith Elena , Andrews Jenny M. , Wise Richard , Honeybourne David 
Published: May 2005

AbstractIn order to quantify intracellular Staphylococcus aureus within a macrophage‐like cell line by a bioluminescence technique, the mouse cell line J774 and opsonized Staphylococcus aureus were incubated together to allow phagocytosis to occur. Experiments using UV microscopy and fluorescent stained S. aureus were performed to determine an estimate of the mean intracellular bacterial numbers. For enumeration of intracellular bacteria by a bioluminescence technique, extracellular bacteria were removed by washing, the macrophages lysed mechanically and osmotically and treated with apyrase to remove somatic ATP. Bacterial cells were washed and the intracellular ATP measured by firefly luciferase bioluminescence in a luminometer. This new method of enumerating intracellular bacteria was compared to the conventional method of viable counts and found to correlate (r = 0.78). The bioluminescence assay developed was found to be a relatively rapid alternative method to the techniques currently used to enumerate intracellular bacteria and could prove advantageous in studies of intracellular killing and effects of antimicrobial agents on intracellular pathogens.
Using discriminant analysis to estimate linear mixing proportions
Authors: Burdick D. S. , Rayens W. S. 
Published: May 2005

AbstractThis paper proposes an elegant, yet straightforward, model for classifying linear mixtures. A linear mixture is defined as a random vector y in which the variable are a (non‐negative) weighted average of corresponding variables, assumed to characterize g component groups. These weights are referred to as ‘mixing proportions’. The model seeks to identify the mixture constituents and estimate the mixing proportions. It is demonstrated within the context of high resolution gas chromatography and the problem of identifying the constituents in polychlorinated biphenyl mixtures.
Chance classifications by non‐parametric linear discriminant functions
Authors: Lavine B. K. , Jurs P. C. , Henry D. R. 
Published: May 2005

AbstractIn applications of pattern recognition techniques to problems in chemical fingerprinting, only limited knowledge about the underlying statistical distribution of the data is generally available. This means that non‐parametric methods must be used. Non‐parametric discriminant functions have been used to provide insight into relationships contained within sets of chemical measurements. However, classification based on random or chance separation can be a serious problem. Monte Carlo simulation studies have been carried out to assess the probability of chance classification for non‐parametric linear discriminants. The level of expected chance classification is a function of the number of observations (the number of samples), the dimensionality of the problem (the number of independent variables per observation), class membership distribution and the covariance structure of the data being examined. An approach for assessing the level of significance of classification scores obtained from real training sets will be presented. These simulation studies establish limits on the approaches that can be taken with real data sets so that chance classification are improbable, and provide information necessary for integrating the data analysis into the overall experimental design.
PLS assessment of the performance of short‐term tests for carcinogens
Authors: Tosato Maria Livia , Cesareo Daniela , Passerini Laura , Clementi Sergio 
Published: May 2005

AbstractPartial least squares modelling in latent variables is applied to the analysis of short‐term test genotoxicity data obtained by testing 42 chemicals, known carcinogens and non‐carcinogens, in 35 different assay systems that are deemed to be potential indicators of carcinogencity. Results of a preliminary analysis of all data, and of a second analysis on a reduced data base, are presented. The latter analysis provided a model explaining 73% of variance, whereby no false negative or positive was predicted among 38 chemicals, in spite of qualitative predictions indicating five false positives and two false negatives. Only nine out of 35 assays appear to be relevant to the description of carcinogenicity/non‐carcinogenicity of chemical substances.
Savitzky‐Golay filtering in particle characterization
Authors: Wolfrum S. M. , Van Veen N. J. A. 
Published: May 2005

AbstractMicrostructure laboratory equipment can most easily be interfaced to computers of the PC generation, which offers the facility to extract more information from the measurements performed. A formulation of the Savitzky‐Golay smoother with a newly developed calculation of the necessary weighting factors provides enhanced flexibility in the choice of the smoothing parameters.
Tensorial calibration: II. Second‐order calibration
Authors: Sanchez Eugenio , Kowalski Bruce R. 
Published: May 2005

AbstractTensorial calibration provides a useful approach to calibration in general. For calibration of instruments that produce two‐dimensional (second‐order) arrays of data per sample, tensoial concepts are as natural a way of solving the calibration problem as vectorial concepts are for the multivariate problem. Similarly, for third‐ and higher‐order data, the tensorial description of calibration is also useful. This paper introduces second‐order calibration from a tensorial point of view. Univariate, multivariate and bilinear approaches to calibration are presented. The generalized rank annihilation method (GRAM) is described from the tensorial perspective, and it is shown that GRAM is equivalent to finding a second‐order tensorial base that spans both tensors (calibration and unknown) with respective diagonal component matrices. GRAM uses a single calibration sample for multicomponent analysis even in the presence of interference. Second‐order bilinear calibration is extended to multiple calibration samples where the effect of collinearities is reduced.
A non‐parametric class modelling technique
Authors: Derde M. P. , Kaufman L. , Massart D. L. 
Published: May 2005

AbstractA non‐parametric method for supervised pattern recognition is presented. The method is of the class modelling type, meaning that a classification rule is developed for each class, using the dissimilarities between the objects of the class. The dissimilarities between the objects within a class are related to the distances between all pairs of training objects. As distance metric, a measure is proposed that takes the correlation between the interval‐scale variables into account, and that moreover can be used for mixed types of variables. The classification rule is based on the construction of a boundary in the measurement space. For the determination of the class boundary, several strategies are proposed and compared.The performance of the technique is evaluated on the basis of several data sets. Comparison with the class modelling technique UNEQ shows its usefulness for practical application.
Variance‐decomposition of pure‐component spectra as a measure of selectivity
Authors: Kalivas John H. 
Published: May 2005

AbstractCare is required for multicomponent analysis if misleading results are to be avoided. The problem of ill‐conditioned calibration matrices is of primary concern. This type of numerical instability is represented as spectral overlap of calibration spectra. Depending on the degree of spectral overlap, the sample concentration estimates can be severely affected. A practical statistical procedure is discussed which tests for the presence of spectral overlap among the pure‐component spectra and simultaneously assesses the degree that concentration estimates may be degraded. Guidelines are developed to ascertain how much departure from spectral orthogonality is acceptable.
The wavelength component vectorgram: A tool for resolving two‐component fluorescent mixtures
Authors: Burdick Donald S. , Tu Xin M. 
Published: May 2005

AbstractWe consider the problem of resolving the total luminescence spectra of two‐component mixtures. Non‐negativity of the constituent spectra is commonly used as a criterion to accomplish this resolution, but its application seldom leads to unique answers. Sometimes, the condition must be relaxed because no solution satisfying non‐negativity exists. In these cases judgments must be made concerning which parts of the spectra will be allowed to go negative and by how much.The wavelength component vectorgramn (WCV) is presented here as a tool for assisting the experimenter in making these judgments. Even when non‐negative resolutions exist, it may happen that resolutions with slight negative elements will more closely match the spectra of the pure constituents. The WCV can also be used as a tool for detecting these cases. The methodology is illustrated with real data from a two‐component mixture.
Classification: Oldtimers and newcomers
Authors: Frank Ildiko E. , Friedman Jerome H. 
Published: May 2005

AbstractClassification and regression techniques are among the most used tools by chemometricians. With classification, the two classic methods are discriminant analysis and SIMCA. In this paper we discuss the connection between these two methods and introduce two new ones of the same family: DASCO (discriminant analysis with shrunken covariances) and RDA (regularized discriminant analysis). We demonstrate on both simulated and real data sets that their performance is superior to the old favorites. This is especially true in small‐sample/high‐dimension settings typical in chemistry.
An improved algorithm for the generalized rank annihilation method
Authors: Wilson Bruce E. , Sanchez Eugenio , Kowalski Bruce R. 
Published: May 2005

AbstractAn improved algorithm for the generalized rank annihilation method (GRAM) is presented. GRAM is a method for multicomponent calibration using two‐dimensional instruments, such as GC‐MS. In this paper an orthonormal base is first computed and used to project the calibration and unknown sample response matrices into a lower‐dimensional subspace. The resulting generalized eigenproblem is then solved using the QZ algorithm. The result of these improvements is that GRAM is computationally more stable, particularly in the case where the calibration sample contains chemical constituents not present in the unknown sample and the unknown contains constituents not present in the calibration (the most general case).
Tensorial resolution: A direct trilinear decomposition
Authors: Sanchez Eugenio , Kowalski Bruce R. 
Published: May 2005

AbstractModern instrumentation in chemistry routinely generates two‐dimensional (second‐order) arrays of data. Considering that most analyses need to compare several samples, the analyst ends up with a three‐dimensional (third‐order) array which is difficult to visualize or interpret with the conventional statistical tools.Some of these data arrays follow the so‐called trilinear model,

These trilinear arrays of data are known to have unique factor analysis decompositions which correspond to the true physical factors that form the data, i.e. given the array ℝ, a unique solution can be found in many cases for each order X, Y and Z. This is in contrast to the well‐known second‐order bilinear data factor analysis, where the abstract solutions obtained are not unique and at best cannot be easily compared with the underlying physical factors owing to a rotational ambiguity.Trilinear decompositions have had the disadvantage, however, that a non‐linear optimization with many parameters is necessary to reach a least‐squares solution. This paper will introduce a method for reducing the problem to a rectangular generalized eigenvalue–eigenvector equation where the eigenvectors are the contravariant form (pseudo‐inverse) of the actual factors. It is shown that the method works well when the factors are linearly independent in at least two orders (e.g. Xir and Yjr are full rank matrices).Finally, it is shown how trilinear decompositions relate to multicomponent calibration, curve resolution and chemical analysis.
The effect of mislabeled samples on the performance of the linear learning machine
Authors: Lavine Barry K. , Ward Anthony J. I. , Han Jian Hwa , Smith Roy‐Keith , Taylor Orley R. 
Published: May 2005

AbstractOver the past 15 years the linear learning machine has been applied to a large number of chemical problems. The learning machine approach is conceptually simple and does not require knowledge about the statistical distribution of the data. However, there are problems associated with this approach. One problem which has not been investigated is the influence of mislabeled samples on the positioning of the hyperplane in feature space. If a few samples in a data set are incorrectly tagged prior to training (i.e. the samples are labeled as members of class 2 even though they are actually members of class 1), it is still possible using the linear learning machine to achieve a classification success rate of 100% for the training set. However, unfavorable results will be obtained for the prediction set. The magnitude of this effect and its potential implications regarding the proper use of the linear learning machine are discussed.