Correlation Methods in Chemical Data Measurement

Horlick, Gary; Hieftje, Gary M.

doi:10.1007/978-1-4615-6734-9_4

Cited by 29 publications

(24 citation statements)

References 100 publications

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“…The timedependent fluorescence decay curve was recorded by an opto-electronic network constructed to measure the cross-correlation (8,(23)(24)(25) between the laser pulse and the resulting fluorescence waveform. In this particular application, the cross-correlation performs a gating function, similar to a boxcar integration (26).…”

Section: Avvva/vvwbmentioning

confidence: 99%

Determination of Atomic and Molecular Excited-State Lifetimes Using an Optoelectronic Cross-Correlation Method

Russo

Hieftje

1982

Appl Spectrosc

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A new optoelectronic cross-correlation technique has been used to measure excited-state lifetimes of several organic fluorophores in solution and of sodium atoms in both air-acetylene and methane-air flames. Capable of time resolution in the picosecond range, the new method was validated by the excellent agreement between measured and literature values for fluorescence lifetimes of the organic species. Lifetime values for Na atoms in flames are among the most precise ever reported and agree closely with values calculated from the known flame gas composition, temperature, and the quenching cross-sections of the two dominant quenching species in the flame, N2 and CO2. From the Na excited-state lifetimes (0.72 ± 0.07 ns for air-acetylene and 0.48 ± 0.08 ns for methane-air flames), quantum efficiencies for atomic fluorescence were calculated.

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Section: Avvva/vvwbmentioning

confidence: 99%

Determination of Atomic and Molecular Excited-State Lifetimes Using an Optoelectronic Cross-Correlation Method

Russo

Hieftje

1982

Appl Spectrosc

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“…However, if y(t) is a randomly varying perturbation, no analytically usable expression can be written for it, instead the solution can be obtained through use of the convolution theorem. From this theorem, cross-correlation functions, C xy(T), fully retain the relative amplitude and phase characteristics of two waveforms, x(t) and y(t), which are correlated (Gaskill, 1978, Habil, 1967Horlick and Hieftje, 1980). Thus, we may correlate y(t!…”

Section: Introductionmentioning

confidence: 97%

“…The basis of the new method lies in the field of linear response theory (Gaskill, 1958;Habil, 1967;Horlick and Hieftje, 1980) and it is from the standpoint of this field that the technique can best be understood. From this standpoint, a conventional flash photolysis experiment is an attempt to measure the impulse response function of a light-sensitive chemical or biological reaction.…”

Section: Introductionmentioning

confidence: 99%

Stochastic Photolysis: A New Method for Measuring Rates of Photosensitive Reactions

et al. 1982

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A new method is introduced for the measurement of photochemical or photobiological reaction rates. Based on linear response theory, the method uses a randomly modulated light source rather than a pulsed one, and uses cross-correlation analysis to extract the desired kinetic information. In operation, a randomly varying light source illuminates the reaction of interest, and the resulting fluctuations in reactant (or product) concentrations are monitored. Mathematical or instrumental cross correlation of the light source variations with those in component concentration then produces the familiar kinetic decay curve. Because the new method produces only minute concentration fluctuations, it can measure reaction rates near equilibrium; moreover, equilibrium position can be shifted by superimposing on the fluctuating light intensity a dc level. Also, because cross correlation is used, the method enjoys high signal-to-noise ratios. In the present study, the utility and practicability of the new technique are demonstrated through examination of the recombination kinetics of photolytically generated iodine atoms.

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“…As for biotyping of microorganisms, two main approaches have been assessed: (1) the coefficient of correlation for FSA and (2) peak table-based methods. Coefficients of correlation are a math algorithm for a comparison of two analytical signals presented as functions; this method can also be applied to spectrometry data and to other areas (Horlick and Hieftje, 1978;Ng and Horlick, 1981). In one of the early studies on the identification of microorganisms by MALDI TOF MS, Arnold R.J. and Reilly J.P. used the composite correlation index for a comparison of E.coli strains (Arnold and Reilly, 1998).…”

Section: Introductionmentioning

confidence: 99%

Creation of an Online Platform for Identification of Microorganisms: Peak Picking or Full-Spectrum Analysis

et al. 2020

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Identification of microorganisms by MALDI-TOF mass spectrometry is a very efficient method with high throughput, speed, and accuracy. However, it is significantly limited by the absence of a universal database of reference mass spectra. This problem can be solved by creating an Internet platform for open databases of protein spectra of microorganisms. Choosing the optimal mathematical apparatus is the pivotal issue for this task. In our previous study we proposed the geometric approach for processing mass spectrometry data, which represented a mass spectrum as a vector in a multidimensional Euclidean space. This algorithm was implemented in a Jacob4 stand-alone package. We demonstrated its efficiency in delimiting two closely related species of the Bacillus pumilus group. In this study, the geometric approach was realized as R scripts which allowed us to design a Web-based application. We also studied the possibility of using full spectra analysis (FSA) without calculating mass peaks (PPA), which is the logical development of the method. We used 74 microbial strains from the collections of ICiG SB RAS, UNIQEM, IEGM, KMM, and VGM as the models. We demonstrated that the algorithms based on peak-picking and analysis of complete data have accuracy no less than that of Biotyper 3.1 software. We proposed a method for calculating cut-off thresholds based on averaged intraspecific distances. The resulting database, raw data, and the set of R scripts are available online at https://icg-test.mydisk.nsc.ru/s/qj6cfZg57g6qwzN.

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Correlation Methods in Chemical Data Measurement

Cited by 29 publications

References 100 publications

Determination of Atomic and Molecular Excited-State Lifetimes Using an Optoelectronic Cross-Correlation Method

Determination of Atomic and Molecular Excited-State Lifetimes Using an Optoelectronic Cross-Correlation Method

Stochastic Photolysis: A New Method for Measuring Rates of Photosensitive Reactions

Creation of an Online Platform for Identification of Microorganisms: Peak Picking or Full-Spectrum Analysis

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