Artículos de revistas: "Spectrum analysis, Mass"

1

Walwil, Abdalla Mustafa. "Analysis of Butyl Butyrate Mass Spectrum." International Journal of Chemistry 10, no. 1 (January 14, 2018): 11. http://dx.doi.org/10.5539/ijc.v10n1p11.

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The aim of this educational work is targeting chemistry students and interested instructors. The presented work will analyze the mass spectrum of butyl butyrate (butyl butanoate). The analysis will concentrate on the mechanisms showing how the characteristic fragments are formed. The mechanisms discussed in this paper include α-cleavage, β-cleavage, McLafferty Rearrangements, first and second proton transfer, a double proton transfer.

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2

Matyshev, A. A. "New method of pulsed mass spectrum analysis." Technical Physics 42, no. 1 (January 1997): 72–75. http://dx.doi.org/10.1134/1.1258653.

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3

Bankova, Zh N., and T. S. Birisen. "Spectral analysis of UV-spectrum elements in steel using portable optical emission spectrometers." Litiyo i Metallurgiya (FOUNDRY PRODUCTION AND METALLURGY), no. 2 (June 9, 2020): 45–47. http://dx.doi.org/10.21122/1683-6065-2020-2-45-47.

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Optical emission spectroscopy is used to determine the mass fraction of elements such as carbon, silicon, manganese, phosphorus, sulfur, chromium, nickel, copper, aluminum, molybdenum, vanadium, titanium, arsenic, tin, boron, calcium, etc. Most of the analytical lines of the analyzed elements are located in the visible light spectrum, but the analytical lines of carbon, phosphorus and sulfur are located in the ultraviolet radiation spectrum.Ultraviolet radiation (UV radiation) is electromagnetic radiation that occupies the spectral range between visible and x ray radiation. The wavelengths of UV radiation are in the range from 10 to 400 nm. The area of UV radiation is divided into: near from 400 to 200 nm; far from 380 to 200 nm; vacuum from 200 to 10 nm.Structural particularities of the structure of the optical system of stationary spectrometers allow determining the mass fraction of chemical elements, including phosphorus and sulfur, with sufficient accuracy and reliability. This article discusses the possibility of determining the mass fractions of phosphorus and sulfur, the analytical lines of which lie in the area of ultraviolet radiation, using portable optical emission spectrometers.

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4

Kelleher, J. K., A. T. Kharroubi, T. A. Aldaghlas, I. B. Shambat, K. A. Kennedy, A. L. Holleran, and T. M. Masterson. "Isotopomer spectral analysis of cholesterol synthesis: applications in human hepatoma cells." American Journal of Physiology-Endocrinology and Metabolism 266, no. 3 (March 1, 1994): E384—E395. http://dx.doi.org/10.1152/ajpendo.1994.266.3.e384.

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Cholesterol synthesis from 13C-labeled precursors produces a discrete spectrum of mass isotopomers detectable using gas chromatography-mass spectrometry. The isotopomer spectral analysis (ISA) method matches the observed spectrum of cholesterol isotopomers with a mathematical model to obtain the best fit of model spectrum to data spectrum. The model was based on multinomial probability expressions that simulate cholesterol synthesis as a condensation of mevalonate fragments. As many as four unknown parameters, representing fluxes between compartments, were included in the model. Models were developed to assess cholesterol synthesis from 13C-enriched precursors including mevalonate, acetate, acetoacetate or octanoate. Models were tested in the human hepatoma cell line, Hep G2, which readily incorporated the 13C substrates into cholesterol. The ISA approach was used to estimate the fractional amount of the cholesterol precursors derived from the 13C substrate and the fraction of total cellular cholesterol synthesized in the presence of the 13C substrate. The study demonstrated the feasibility of the ISA approach for a condensation biosynthesis that is not a simple polymerization and for models with more than two unknown parameters.

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5

Jimbo, Shuichi, and Yoshihisa Morita. "Lyapunov function and spectrum comparison for a reaction–diffusion system with mass conservation." Journal of Differential Equations 255, no. 7 (October 2013): 1657–83. http://dx.doi.org/10.1016/j.jde.2013.05.021.

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6

Chen, HaiFeng, BoTao Fan, HaiRong Xia, Michel Petitjean, ShenGang Yuan, Annick Panaye, and Jean-Pierre Doucet. "MASSIS: A Mass Spectrum Simulation System. 1. Principle and Method." European Journal of Mass Spectrometry 9, no. 3 (June 2003): 175–86. http://dx.doi.org/10.1255/ejms.549.

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A mass spectrum simulation system was developed. The simulated spectrum for a given target structure is computed based on the cleavage knowledge and statistical rules established and stored in pivot databases: cleavage rule knowledge, functional groups, small fragments and fragment-intensity relationships. These databases were constructed from correlation charts and statistical analysis of a large population of organic mass spectra using data mining techniques. Since 1980, several systems have been proposed for mass spectrum simulation, but at present there is no commercial software available. This shows the complexity and difficulties in the development of such a system. The reported mass spectral simulation system in this paper could be the first general software for organic chemistry use.

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7

Hughey, Christine A., Christopher L. Hendrickson, Ryan P. Rodgers, Alan G. Marshall, and Kuangnan Qian. "Kendrick Mass Defect Spectrum: A Compact Visual Analysis for Ultrahigh-Resolution Broadband Mass Spectra." Analytical Chemistry 73, no. 19 (October 2001): 4676–81. http://dx.doi.org/10.1021/ac010560w.

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8

Berkdemir, Cuneyt, Shi-Bo Cheng, and A. W. Castleman. "Assigning the mass spectrum of NbN−: Photoelectron imaging spectroscopy and nominal-mass counterpart analysis." International Journal of Mass Spectrometry 365-366 (May 2014): 222–24. http://dx.doi.org/10.1016/j.ijms.2014.03.011.

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9

ANANTHANARAYAN, B., and P. N. PANDITA. "SPARTICLE MASS SPECTRUM IN GRAND UNIFIED THEORIES." International Journal of Modern Physics A 22, no. 19 (July 30, 2007): 3229–59. http://dx.doi.org/10.1142/s0217751x07036889.

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We carry out a detailed analysis of sparticle mass spectrum in supersymmetric grand unified theories. We consider the spectroscopy of the squarks and sleptons in SU (5) and SO (10) grand unified theories, and show how the underlying supersymmetry breaking parameters of these theories can be determined from a measurement of different sparticle masses. This analysis is done analytically by integrating the one-loop renormalization group equations with appropriate boundary conditions implied by the underlying grand unified gauge group. We also consider the impact of nonuniversal gaugino masses on the sparticle spectrum, especially the neutralino and chargino masses which arise in supersymmetric grand unified theories with nonminimal gauge kinetic function. In particular, we study the interrelationships between the squark and slepton masses which arise in grand unified theories at the one-loop level, which can be used to distinguish between the different underlying gauge groups and their breaking pattern to the Standard Model gauge group. We also comment on the corrections that can affect these one-loop results.

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10

Sergeev, V. А., and S. Е. Reschikoff. "Adaptive algorithms for measuring low-frequency noise parameters of semiconductor devices under mass control." Izmeritel`naya Tekhnika, no. 11 (2020): 59–64. http://dx.doi.org/10.32446/0368-1025it.2020-11-59-64.

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The solution of the problem of increasing the confidence and efficiency of quality control of semiconductor devices is considered. The analysis of conditions for measuring the power spectral density of low – frequency noise of semiconductor devices with a spectrum of the form (γ – the spectrum shape indicator) under mass quality control is presented. The error in measuring the power spectral density under the specified measurement conditions strongly depends on the value of the spectrum shape indicator. Adaptive algorithms for measuring low-frequency noise parameters are proposed for cases of a given limit error in measuring the power spectral density and a given time for a single measurement. The proposed algorithms include a preliminary estimation of the value of the spectrum shape indicator and subsequent measurement of the noise power spectral density at the optimal filter bandwidth. The optimal filter bandwidth is determined based on the results of a preliminary assessment of the spectrum shape indicator. For both cases, we obtained estimates of the gain in the sense of the average for the set (ensemble) of controlled products. The possibility of adaptive or cognitive adjustment of the measurement system parameters in the control process based on the results of evaluating sample averages in the training sample is discussed.

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11

Kharroubi, A. T., T. M. Masterson, T. A. Aldaghlas, K. A. Kennedy, and J. K. Kelleher. "Isotopomer spectral analysis of triglyceride fatty acid synthesis in 3T3-L1 cells." American Journal of Physiology-Endocrinology and Metabolism 263, no. 4 (October 1, 1992): E667—E675. http://dx.doi.org/10.1152/ajpendo.1992.263.4.e667.

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A new analysis of stable isotope data for biosynthesis reaction, isotopomer spectral analysis (ISA), is demonstrated. ISA is theoretically applicable for polymerization biosynthesis where data are collected using selected ion-monitoring gas chromatography-mass spectrometry. ISA utilizes the discrete spectrum of isotopomer abundances and the multinomial distribution to estimate two key parameters related to the biosynthesis. These parameters are 1) the dilution of the precursor immediately before biosynthesis and 2) the dilution of the newly synthesized product in the sampled compartment. Differentiated 3T3-L1 cells incorporated 2 mM [1,2-13C]acetate into triglyceride palmitate, yielding a spectrum of mass isotopomers of palmitate. The set of equations for the first nine isotopomers were solved for the two parameters using nonlinear regression. We found that precursor dilutions for acetate and glucose were constant over time, whereas the product dilution parameter increased with time, as expected for cells accumulating triglyceride palmitate. Mathematical procedures are presented for calculating 1) the predicted isotopomer fractional abundance values and 2) the correction for atoms other than the tracer atom in the mass ion.

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12

Ekimoff, David, Ann Marie Van Norstrand, and David A. Mowers. "Semiquantitative Survey Capabilities of Inductively Coupled Plasma Mass Spectrometry." Applied Spectroscopy 43, no. 7 (September 1989): 1252–57. http://dx.doi.org/10.1366/0003702894203534.

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The capabilities of Inductively Coupled Plasma Mass Spectrometry for elemental survey analysis have been characterized. The analysis is a three-step process which involves collecting a spectrum from mass 5 to 240, deconvolving the spectrum into elemental constituents, and converting the elemental count rates to concentrations. The entire process takes less than 10 min per sample. Detection limits are generally less than 1 ng/mL, and the precision of 16 replicate analyses of a sample is between 5 and 20% for the majority of the elements detected. It was determined that the figures of merit for this analysis did not vary significantly as the matrix changed.

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13

Jin, Changhao. "Analysis of the hadronic invariant mass spectrum in inclusive charmless semileptonicBdecays." Physical Review D 57, no. 11 (June 1, 1998): 6851–56. http://dx.doi.org/10.1103/physrevd.57.6851.

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14

Epstein, Jonathan A., Paul S. Blank, Brian C. Searle, Aaron D. Catlin, Stephanie M. Cologna, Matthew T. Olson, Peter S. Backlund, Jens R. Coorssen, and Alfred L. Yergey. "ProteinProcessor: A probabilistic analysis using mass accuracy and the MS spectrum." PROTEOMICS 16, no. 18 (September 2016): 2480–90. http://dx.doi.org/10.1002/pmic.201600137.

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15

Zhou, Na, Jie Wang, Yaqin Yu, Jieping Shi, Xiaokun Li, Bin Xu, and Qiong Yu. "Mass spectrum analysis of serum biomarker proteins from patients with schizophrenia." Biomedical Chromatography 28, no. 5 (November 20, 2013): 654–59. http://dx.doi.org/10.1002/bmc.3084.

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16

Jin, Min Chao, Bao Fu Wang, Zhong Ren Feng, and Xiong Jiang Wang. "Seismic Response Analysis of Long Span Cable-Stayed Bridge by Response Spectrum Method." Applied Mechanics and Materials 204-208 (October 2012): 1992–96. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.1992.

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Based on response spectrum method, the seismic behavior of a long span cable-stayed bridge is investigated through three dimensional finite element model established by ANSYS. By calculating the cumulative effective mass factors of the bridge, the minimum number of modes used for modal superposition analysis is obtained. Design acceleration response spectrums under two probabilities are used in the analysis. The response spectrums are input in the bridge longitudinal direction, vertical direction, transverse direction and combined horizontal and vertical directions. Displacements and internal forces results show that vertical component of the ground motion greatly influences the response of the bridge and there is significant difference between the results of the two probabilities.

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17

Peng, Ke-Xin, Jian-Bo Yang, Xian-Guo Tuo, Hua Du, and Rui-Xue Zhang. "Research on PGNAA adaptive analysis method with BP neural network." Modern Physics Letters B 30, no. 32n33 (November 30, 2016): 1650386. http://dx.doi.org/10.1142/s0217984916503863.

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A new approach method to dealing with the puzzle of spectral analysis in prompt gamma neutron activation analysis (PGNAA) is developed and demonstrated. It consists of utilizing BP neural network to PGNAA energy spectrum analysis which is based on Monte Carlo (MC) simulation, the main tasks which we will accomplish as follows: (1) Completing the MC simulation of PGNAA spectrum library, we respectively set mass fractions of element Si, Ca, Fe from 0.00 to 0.45 with a step of 0.05 and each sample is simulated using MCNP. (2) Establishing the BP model of adaptive quantitative analysis of PGNAA energy spectrum, we calculate peak areas of eight characteristic gamma rays that respectively correspond to eight elements in each individual of 1000 samples and that of the standard sample. (3) Verifying the viability of quantitative analysis of the adaptive algorithm where 68 samples were used successively. Results show that the precision when using neural network to calculate the content of each element is significantly higher than the MCLLS.

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18

Shen Yi, Zhang Huang, Liu Xing-Guang, Xia Lian-Sheng, and Yang An-Min. "Outgassing mass spectrum analysis with intense pulsed emission of carbon nanotube cathode." Acta Physica Sinica 60, no. 8 (2011): 080702. http://dx.doi.org/10.7498/aps.60.080702.

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19

Xu, Jing Bo, Xin Qian Bian, and Ming Yu Fu. "Simulation and Spectral Analysis of Sea Wave." Advanced Materials Research 532-533 (June 2012): 1287–91. http://dx.doi.org/10.4028/www.scientific.net/amr.532-533.1287.

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This paper deals with the method of simulating sea wave for decreasing its disturbance in the watercraft navigating. Firstly the ITTC two-parameter spectrum is selected as the power spectrum of sea wave to be simulated. Secondly the selected power spectrum is parted on a prescription composed of drugs of equal amount energy, and the harmonic frequency is determined by calculating the mass center of each section. Each order harmonic is synthesized on the basis of the Longuet-Higgins model in time domain. Finally, the simulation algorithm based on energy in part is presented and the simulated sea wave with time and space are determined. The simulation accuracy arrives at 1.6% compared with the ideal sea wave spectrum by the spectrum analysis of the simulated sea wave in Welch. That testifies the validity of this method and provides the watercraft movement parameters filtering with reliable exciting signals.

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20

Kinnison, Adam L., and Peter Mörters. "Simultaneous Multifractal Analysis of the Branching and Visibility Measure on a Galton-Watson Tree." Advances in Applied Probability 42, no. 01 (March 2010): 226–45. http://dx.doi.org/10.1017/s0001867800003980.

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On the boundary of a Galton-Watson tree we can define thevisibility measureby splitting mass equally between the children of each vertex, and thebranching measureby splitting unit mass equally between all vertices in thenth generation and then lettingngo to infinity. The multifractal structure of each of these measures is well studied. In this paper we address the question of ajointmultifractal spectrum, i.e. we ask for the Hausdorff dimension of the boundary points whichsimultaneouslyhave an unusual local dimension for both these measures. The resulting two-parameter spectrum exhibits a number of surprising new features, among them the emergence of a swallowtail-shaped spectrum for the visibility measure in the presence of a nontrivial condition on the branching measure.

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21

Miller, Keith. "On the Mass Matrix Spectrum Bounds of Wathen and the Local Moving Finite Elements of Baines." SIAM Journal on Numerical Analysis 29, no. 1 (February 1992): 89–106. http://dx.doi.org/10.1137/0729006.

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22

Jawad, Muhammad, Jens Soltwisch, Klaus Dreisewerd, and Lars Linsen. "Interactive Visual Analysis of Mass Spectrometry Imaging Data Using Linear and Non-Linear Embeddings." Information 11, no. 12 (December 9, 2020): 575. http://dx.doi.org/10.3390/info11120575.

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Mass spectrometry imaging (MSI) is an imaging technique used in analytical chemistry to study the molecular distribution of various compounds at a micro-scale level. For each pixel, MSI stores a mass spectrum obtained by measuring signal intensities of thousands of mass-to-charge ratios (m/z-ratios), each linked to an individual molecular ion species. Traditional analysis tools focus on few individual m/z-ratios, which neglects most of the data. Recently, clustering methods of the spectral information have emerged, but faithful detection of all relevant image regions is not always possible. We propose an interactive visual analysis approach that considers all available information in coordinated views of image and spectral space visualizations, where the spectral space is treated as a multi-dimensional space. We use non-linear embeddings of the spectral information to interactively define clusters and respective image regions. Of particular interest is, then, which of the molecular ion species cause the formation of the clusters. We propose to use linear embeddings of the clustered data, as they allow for relating the projected views to the given dimensions. We document the effectiveness of our approach in analyzing matrix-assisted laser desorption/ionization (MALDI-2) imaging data with ground truth obtained from histological images.

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23

Zhislin, G. M. "The Hamiltonians of Pseudorelativistic Atoms with Finite-Mass Nuclei: The Structure of the Discrete Spectrum." Functional Analysis and Its Applications 38, no. 2 (April 2004): 151–56. http://dx.doi.org/10.1023/b:faia.0000034046.99025.5b.

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24

Peretti, S., D. Ségransan, B. Lavie, S. Desidera, A. L. Maire, V. D’Orazi, A. Vigan, et al. "Orbital and spectral analysis of the benchmark brown dwarf HD 4747B." Astronomy & Astrophysics 631 (November 2019): A107. http://dx.doi.org/10.1051/0004-6361/201732454.

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Context. The study of high-contrast imaged brown dwarfs and exoplanets depends strongly on evolutionary models. To estimate the mass of a directly imaged substellar object, its extracted photometry or spectrum is used and adjusted with model spectra together with the estimated age of the system. These models still need to be properly tested and constrained. HD 4747B is a brown dwarf close to the H burning mass limit, orbiting a nearby (d = 19.25 ± 0.58 pc), solar-type star (G9V); it has been observed with the radial velocity method for over almost two decades. Its companion was also recently detected by direct imaging, allowing a complete study of this particular object. Aims. We aim to fully characterize HD 4747B by combining a well-constrained dynamical mass and a study of its observed spectral features in order to test evolutionary models for substellar objects and to characterize its atmosphere. Methods. We combined the radial velocity measurements of High Resolution Echelle Spectrometer (HIRES) and CORALIE taken over two decades and high-contrast imaging of several epochs from NACO, NIRC2, and SPHERE to obtain a dynamical mass. From the SPHERE data we obtained a low-resolution spectrum of the companion from Y to H band, and two narrow band-width photometric measurements in the K band. A study of the primary star also allowed us to constrain the age of the system and its distance. Results. Thanks to the new SPHERE epoch and NACO archival data combined with previous imaging data and high-precision radial velocity measurements, we were able to derive a well-constrained orbit. The high eccentricity (e = 0.7362 ± 0.0025) of HD 4747B is confirmed, and the inclination and the semi-major axis are derived (i = 47.3 ± 1.6°, a = 10.01 ± 0.21 au). We derive a dynamical mass of mB = 70.0 ± 1.6 MJup, which is higher than a previous study but in better agreement with the models. By comparing the object with known brown dwarfs spectra, we derive a spectral type of L9 and an effective temperature of 1350 ± 50 K. With a retrieval analysis we constrain the oxygen and carbon abundances and compare them with the values from the HR 8799 planets.

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25

Kinnison, Adam L., and Peter Mörters. "Simultaneous Multifractal Analysis of the Branching and Visibility Measure on a Galton-Watson Tree." Advances in Applied Probability 42, no. 1 (March 2010): 226–45. http://dx.doi.org/10.1239/aap/1269611151.

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On the boundary of a Galton-Watson tree we can define the visibility measure by splitting mass equally between the children of each vertex, and the branching measure by splitting unit mass equally between all vertices in the nth generation and then letting n go to infinity. The multifractal structure of each of these measures is well studied. In this paper we address the question of a joint multifractal spectrum, i.e. we ask for the Hausdorff dimension of the boundary points which simultaneously have an unusual local dimension for both these measures. The resulting two-parameter spectrum exhibits a number of surprising new features, among them the emergence of a swallowtail-shaped spectrum for the visibility measure in the presence of a nontrivial condition on the branching measure.

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26

Tarasov, A. E. "Be Stars in Roche-Lobe Interacting Binaries." International Astronomical Union Colloquium 175 (2000): 644–55. http://dx.doi.org/10.1017/s0252921100056700.

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AbstractDifferent types of massive interacting binaries with Be components are discussed. Due to mass exchange, Be stars in these systems have some peculiar characteristics. Often it is even difficult to find traces of the Be star and/or mass-losing star in the optical region of the spectrum. Using the value of the orbital period as a primary parameter, it is possible to divide all massive interacting binaries into two large groups: short-period or classical Algols and long-period binaries. The last group includes a number of very active mass transfer systems named as W Serpentis. There is also a small group of double systems whose stars do not fill their Roche lobes but have emission lines in the spectrum. Properties of their spectral variability are discussed. Analysis of each group lets us find different behaviours in mass exchange that depend on the size of their Roche lobes.

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27

Hamilton, J. G. C., R. P. Brazil, E. D. Morgan, and B. Alexander. "Chemical analysis of oxygenated homosesquiterpenes: a putative sex pheromone from Lutzomyia lichyi (Diptera: Psychodidae)." Bulletin of Entomological Research 89, no. 2 (February 1999): 139–45. http://dx.doi.org/10.1017/s000748539900022x.

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AbstractLutzomyia lichyi (Floch & Abbonenc) is a suggested secondary vector of Leishmania in Colombia. Taxonomically, L. lichyi is very closely related to the L. longipalpis (Lutz & Neiva) species complex. Male members of the complex can be distinguished by their sex pheromones which are produced in papules found grouped together in pale patches on tergites 3 or tergites 3 and 4. Male L. lichyi also have papules, very similar in appearance to those of the L. longipalpis species complex but distributed on tergites 4, 5, 6 and 7. Chemical analysis of male L. lichyi hexane extracts has revealed the presence of two novel oxygenated methylsesquiterpenes. The two major oxygenated terpenes found in the extract of L. lichyi males are tentatively characterized as a primary and tertiary alcohol. The mass spectrum of the proposed primary alcohol is very similar to the published mass spectrum of 3-methyl-α-himachalene, the sex pheromone produced by the Jacobina chemotype of the L. longipalpis complex. The mass spectrum of the proposed tertiary alcohol also has similarities to the 3-methyl-α-himachalene sex pheromone.

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28

NAKAMOTO, Takamichi. "Analysis of Chemical Data Using Deep Learning Prediction of Odor Impression by Mass-Spectrum Data Analysis." Journal of the Japan Society of Colour Material 93, no. 11 (November 20, 2020): 353–60. http://dx.doi.org/10.4011/shikizai.93.353.

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29

Zhang, T., W. Zhu, and R. McGraw. "Joint cluster and non-negative least squares analysis for aerosol mass spectrum data." Journal of Physics: Conference Series 125 (July 1, 2008): 012026. http://dx.doi.org/10.1088/1742-6596/125/1/012026.

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30

Peng, Jinxing, Guanyi Chen, Zhihua Fan, Qunhui Lin, and Deqin Wang. "Different Methods for Evaluating Pinewood Sawdust Pyrolysis Kinetics by Thermogravimetry Mass Spectrum Analysis." Journal of Biobased Materials and Bioenergy 5, no. 3 (September 1, 2011): 324–30. http://dx.doi.org/10.1166/jbmb.2011.1156.

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31

Noya, H., N. Konno, Y. Uehara, and H. Nakamura. "The diquark cluster model analysis for the mass spectrum of the multiquark system." Nuclear Physics B - Proceedings Supplements 21 (June 1991): 335–40. http://dx.doi.org/10.1016/0920-5632(91)90274-i.

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32

Hsu, H., Y. R. Li, Y. C. Wang, H. K. Liao, and Y. J. Chen. "4P-1160 A mass spectrum analysis method for detection of C-reactive protein." Atherosclerosis Supplements 4, no. 2 (January 2003): 330. http://dx.doi.org/10.1016/s1567-5688(03)91416-4.

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33

Gammie, Charles F., Yen‐Ting Lin, James M. Stone, and Eve C. Ostriker. "Analysis of Clumps in Molecular Cloud Models: Mass Spectrum, Shapes, Alignment, and Rotation." Astrophysical Journal 592, no. 1 (July 20, 2003): 203–16. http://dx.doi.org/10.1086/375635.

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34

Feng, Chenghong, Zhe Bi, and Hongxiao Tang. "Electrospray Ionization Time-of-Flight Mass Spectrum Analysis Method of Polyaluminum Chloride Flocculants." Environmental Science & Technology 49, no. 1 (December 11, 2014): 474–80. http://dx.doi.org/10.1021/es503681p.

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35

Yang Xiao-Dong, Ning Xin-Bao, He Ai-Jun, and Du Si_Dan. "Mass exponent spectrum analysis of human ECG signals based on multiple scale factors." Acta Physica Sinica 57, no. 3 (2008): 1514. http://dx.doi.org/10.7498/aps.57.1514.

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36

Koo, Sandy P. S., Tanja Junkers, and Christopher Barner-Kowollik. "Quantitative Product Spectrum Analysis of Poly(butyl acrylate) via Electrospray Ionization Mass Spectrometry." Macromolecules 42, no. 1 (November 25, 2008): 62–69. http://dx.doi.org/10.1021/ma801196w.

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37

Sharma, Prince, Rahul Sharma, Chetana Jain, and Anjan Dutta. "Broad-band spectral analysis of LMXB XTE J1710−281 with Suzaku." Monthly Notices of the Royal Astronomical Society 496, no. 1 (June 1, 2020): 197–205. http://dx.doi.org/10.1093/mnras/staa1516.

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ABSTRACT This work presents the broad-band time-averaged spectral analysis of neutron star (NS) low-mass X-ray binary, XTE J1710−281 by using the Suzaku archival data. The source was in a hard or an intermediate spectral state during this observation. This is the first time that a detailed spectral analysis of the persistent emission spectra of XTE J1710−281 has been done up to 30 keV with improved constraints on its spectral parameters. By simultaneously fitting the X-ray Imaging Spectrometer (0.6–9.0 keV) and the HXD-PIN (15.0–30.0 keV) data, we have modelled the persistent spectrum of the source with models comprising a soft component from accretion disc and/or NS surface/boundary layer and a hard Comptonizing component. The 0.6–30 keV continuum with neutral absorber can be described by a multicolour disc blackbody with an inner disc temperature of kTdisc = 0.28 keV, which is significantly Comptonized by the hot electron cloud with electron temperature of kTe ≈ 5 keV and described by photon index Γ = 1.86. A more complex three-component model comprising a multicolour disc blackbody ≈0.30 keV, single-temperature blackbody ≈0.65 keV, and Comptonization from the disc, partially absorbed (about 38 per cent) by an ionized absorber (log(ξ) ≈ 4) describes the broad-band spectrum equally well.

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38

Wei, Yuan, Zhaobo Chen, and Earl H. Dowell. "Nonlinear Characteristics Analysis of a Rotor-Bearing-Brush Seal System." International Journal of Structural Stability and Dynamics 18, no. 05 (May 2018): 1850063. http://dx.doi.org/10.1142/s0219455418500633.

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The vibration response and nonlinear dynamic behavior of a rotor-bearing-brush seal system were investigated with a new seal force model of the brush seal. The nonlinear oil–film force model was adopted based on a short bearing assumption. The dimensionless equation of motion was solved using the fourth order Runge–Kutta method. The effects of key parameters including rotor speed, installation spacing of the brush seal, disk eccentricity, disk mass, and journal mass on the nonlinear dynamic characteristics of rotor-bearing-brush seal system were determined and compared under different operating conditions with a bifurcation diagram, time history, axis orbit, poincaré map, frequency spectrum, and spectrum cascade. The results showed that the system response contained various nonlinear phenomena, such as periodic motion, multi-periodic motion, and quasi-periodic motion. The interaction of the rotor speed, installation spacing of the brush seal, disk eccentricity, disk mass, and journal mass could seriously affect the stability and working condition of the system. This study provides a theoretical support for the selection of key design parameters and further understanding of the nonlinear characteristics of rotor-bearing-seal systems with a brush seal.

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39

Novikov, L. V., V. V. Manoilov, A. G. Kuzmin, Yu A. Titov, I. V. Zarutsky, A. O. Nefedov, A. V. Nefedova, and A. I. Arseniev. "EXPRESS DIAGNOSTICS OF DISEASES BASED ON A QUADRUPOLE MASS SPECTROMETER ANALYSIS OF EXHALED AIR." NAUCHNOE PRIBOROSTROENIE 30, no. 4 (November 30, 2020): 94–105. http://dx.doi.org/10.18358/np-30-4-i94105.

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The method is proposed for express diagnostics of diseases according to the data of mass spectrometric analysis of exhaled air. An algorithm for calculating the probability of diseases has been developed and tested. The results of data processing of patients treated in two oncological clinics are presented. The calculation of the probability of disease according to the data of mass spectrometric analysis of exhaled air is based on attributing the mass spectrum of the tested patient to the mass-spectra of the corresponding control group. Each control group is formed by collecting an array of spectra from at least ten patients with the same disease. Diagnostics is performed by transforming the matrix of spectra of the control group and the spectrum of a patient being tested into the space of the principal components. The probability of a disease is determined by the Euclidean distance of the patient's coordinates from the centroid of the control group in the multidimensional space of these principal components.

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40

CULBERTSON, RAY. "ANALYSIS OF DIPHOTON EVENTS AT CDF." International Journal of Modern Physics A 20, no. 15 (June 20, 2005): 3270–72. http://dx.doi.org/10.1142/s0217751x05026315.

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The Collider Detector at Fermilab Collaboration has analyzed events with two photons in the central detector. The cross section is measured and compared to theoretical models. The diphoton mass spectrum is searched for anomalous narrow peaks and a search for gauge–mediated SUSY is performed with events with two photons and missing Et.

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41

Kesavan S, Sudha Sri, Usha Nandhini S, and Girija Vasudevan. "CHROMATOGRAPHY-BASED PARTIAL PURIFICATION AND CHARACTERIZATION OF ANTIMICROBIAL COMPOUND ISOLATED FROM A TERRESTRIAL STREPTOMYCES." Asian Journal of Pharmaceutical and Clinical Research 11, no. 2 (February 1, 2018): 83. http://dx.doi.org/10.22159/ajpcr.2018.v11i2.22501.

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Objectives: A potent Streptomyces strain isolated from garden soil samples of Sathyabama University, Chennai, and the characterization and its antimicrobial activity was reported previously. This report deals with partial purification and characterization of the partially purified antimicrobial compound by liquid chromatography-mass spectrum (LC-MS) method.Method: The crude extract was characterized by ultra violet-visible spectrum (UV) and Fourier transform infrared spectroscopy (FTIR) subsequently partial purification was done by thin-layer chromatography, and the bands were used for LC-MS analysis. The obtained mass spectrum was searched in NIST for species data by molecular weight. The compound was identified by comparing the mass spectrum with the known compounds mass spectrum having 98-100% identical. The biological activity of the identified compound was searched in PubChem.Results: The UV and FTIR spectrum indicate the presence of hydroxyl group, aliphatic chain, aromatic, aliphatic amines, and ethers in the crude extract. The LC-MS spectrum revealed the presence of 12 compounds in high intensity resembling antimicrobial compounds such as imidazole, N-trifluoroacetyl, cyclohexane, 2-nitro, and stigmasterol.Conclusion: The instrumental analysis shows the presence of 14 different compounds, and PubChem compound search shows these compounds having various biological activities including antibacterial, antifungal, anticancer, antitumor, and antidepressant. This report insists us further to evaluate the anticancer, antitumor, and antitrypanosomal activities of the partially purified compound.

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42

Kim, Seongho, Ikuko Kato, and Xiang Zhang. "Comparative Analysis of Binary Similarity Measures for Compound Identification in MassSpectrometry-Based Metabolomics." Metabolites 12, no. 8 (July 26, 2022): 694. http://dx.doi.org/10.3390/metabo12080694.

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Compound identification is a critical step in untargeted metabolomics. Its most important procedure is to calculate the similarity between experimental mass spectra and either predicted mass spectra or mass spectra in a mass spectral library. Unlike the continuous similarity measures, there is no study to assess the performance of binary similarity measures in compound identification, even though the well-known Jaccard similarity measure has been widely used without proper evaluation. The objective of this study is thus to evaluate the performance of binary similarity measures for compound identification in untargeted metabolomics. Fifteen binary similarity measures, including the well-known Jaccard, Dice, Sokal–Sneath, Cosine, and Simpson measures, were selected to assess their performance in compound identification. using both electron ionization (EI) and electrospray ionization (ESI) mass spectra. Our theoretical evaluations show that the accuracy of the compound identification was exactly the same between the Jaccard, Dice, 3W-Jaccard, Sokal–Sneath, and Kulczynski measures, between the Cosine and Hellinger measures, and between the McConnaughey and Driver–Kroeber measures, which were practically confirmed using mass spectra libraries. From the mass spectrum-based evaluation, we observed that the best performing similarity measures were the McConnaughey and Driver–Kroeber measures for EI mass spectra and the Cosine and Hellinger measures for ESI mass spectra. The most robust similarity measure was the Fager–McGowan measure, the second-best performing similarity measure in both EI and ESI mass spectra.

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43

Dong, Lihu, Danqing Song, and Guangwei Liu. "Seismic Wave Propagation Characteristics and Their Effects on the Dynamic Response of Layered Rock Sites." Applied Sciences 12, no. 2 (January 12, 2022): 758. http://dx.doi.org/10.3390/app12020758.

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To investigate the seismic response of layered rock sites, a multidomain analysis method was proposed. Three finite element models with infinite element boundaries for layered sites were analysed. The results of this multidomain analysis show that stratum properties and elevation have an impact on wave propagation characteristics and the dynamic response of layered sites. Compared with the rock mass, the overlying gravel soil has a greater dynamic amplification effect at the sites. A time domain analysis parameter PGA(IMF) was proposed to analyse the effects of different strata on the seismic magnification effect of layered sites, and its application was also discussed in comparison with PGA. According to the frequency domain analysis, the interface of the rock mass strata has a low impact on the Fourier spectrum characteristics of the sites, but gravel soil has a great magnification effect on the spectrum amplitude in the high-frequency band (≥30 Hz) of waves. Moreover, the stratum properties have a great influence on the shape and peak value of the Hilbert energy and marginal spectrum at layered sites. When waves propagate from hard rock to soft rock, the peak value of the Hilbert energy spectrum changes from single to multiple peaks; then, in gravelly soil, the Hilbert energy spectral peak, its nearby amplitude and the amplitude in the high-frequency band (28–36 Hz) are obviously amplified. The frequency components and amplitude of the marginal spectrum become more abundant and larger from rock to gravelly soil in the high-frequency band (28–35 Hz).

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44

Jin, Xin, Xin Liu, Jinyun Guo, and Yi Shen. "Multi-Channel Singular Spectrum Analysis on Geocenter Motion and Its Precise Prediction." Sensors 21, no. 4 (February 17, 2021): 1403. http://dx.doi.org/10.3390/s21041403.

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Geocenter is the center of the mass of the Earth system including the solid Earth, ocean, and atmosphere. The time-varying characteristics of geocenter motion (GCM) reflect the redistribution of the Earth’s mass and the interaction between solid Earth and mass loading. Multi-channel singular spectrum analysis (MSSA) was introduced to analyze the GCM products determined from satellite laser ranging data released by the Center for Space Research through January 1993 to February 2017 for extracting the periods and the long-term trend of GCM. The results show that the GCM has obvious seasonal characteristics of the annual, semiannual, quasi-0.6-year, and quasi-1.5-year in the X, Y, and Z directions, the annual characteristics make great domination, and its amplitudes are 1.7, 2.8, and 4.4 mm, respectively. It also shows long-period terms of 6.09 years as well as the non-linear trends of 0.05, 0.04, and –0.10 mm/yr in the three directions, respectively. To obtain real-time GCM parameters, the MSSA method combining a linear model (LM) and autoregressive moving average model (ARMA) was applied to predict GCM for 2 years into the future. The precision of predictions made using the proposed model was evaluated by the root mean squared error (RMSE). The results show that the proposed method can effectively predict GCM parameters, and the prediction precision in the three directions is 1.53, 1.08, and 3.46 mm, respectively.

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45

Mao, Haoyu, Min Zhang, Biao Li, and Nuwen Xu. "Stability Analysis of the Left Bank Slope of Baihetan Hydropower Station Based on the MF-DFA Method." Advances in Civil Engineering 2020 (July 31, 2020): 1–19. http://dx.doi.org/10.1155/2020/8898318.

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Based on the left bank slope of Baihetan hydropower station in Southwestern China, a high-precision microseismic monitoring system was established. An early warning model of surrounding rock mass deformation and failure based on MF-DFA was proposed. The results showed that the multifractal characteristics of the microseismic and blasting waveform time series in the left bank slope were obvious, and the multifractal spectrum width of the blasting waveform is much larger than that of microseismic waveform. Before the slope cracks increased, the multifractal time-varying response characteristics of microseismic waveform showed strong regularity, which could be regarded as a precursor of surrounding rock mass deformation. Before the deformation and failure of surrounding rock mass, the multifractal spectrum width Δα showed an increasing trend while the multifractal spectrum of microseismic waveforms Δf(α) presented a decreasing trend, which can be regarded as a precursor of surrounding rock mass deformation; when deformation and failure occurred, Δα showed a decreasing trend and Δf(α) showed an increasing trend, which can be regarded as a deformation failure period; after the occurrence of deformation and failure, both Δα and Δf(α) showed a steady trend, and Δf(α) would approach to the zero line, which can be regarded as a stable period.

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46

Feldzensztajn, Mateusz, Paweł Wierzba, and Adam Mazikowski. "Examination of Spectral Properties of Medicinal Plant Leaves Grown in Different Lighting Conditions Based on Mint Cultivation." Sensors 21, no. 12 (June 15, 2021): 4122. http://dx.doi.org/10.3390/s21124122.

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Cultivation in controlled environmental conditions can provide good quality medicinal herbs with consistent properties. A sensing system that can determine the contents of medicinal substances in plants using spectral characteristics of leaves would be a valuable tool. Viability of such sensing approach for mint had to be confirmed experimentally, as no data correlating contents of medicinal substances with spectral characteristics of leaves are available, to the best of authors’ knowledge. In the first stage, presented in this paper, the influence of lighting on mint (Mentha rotundifolia) grown on a small hydroponic plantation was studied. Spectral characteristics of leaves were recorded by a spectrophotometer and colorimetric analysis was used to investigate the relationship between these characteristics and the spectrum of lighting. Dry mass yield was measured to test its dependence on the lighting. Dependence of chromaticity of leaves on the spectrum of light used in the cultivation was confirmed. Averaged spectra of leaves are distinguishable using a spectrophotometer and—in most cases—by a human observer. A partial correlation is observed between dry mass yield and the spectrum of lighting. Obtained results justify further research into the correlation between lighting and the contents of biological substances in medicinal plants using spectral characteristics of leaves.

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47

Khangale, Z. N., P. A. Woudt, S. B. Potter, B. Warner, D. Kilkenny, and K. van der Heyden. "A spectroscopic analysis of the eclipsing nova-like EC 21178−5417 – discovery of spiral density structures." Monthly Notices of the Royal Astronomical Society 495, no. 1 (March 13, 2020): 637–49. http://dx.doi.org/10.1093/mnras/staa680.

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ABSTRACT We present phase-resolved optical spectroscopy of the eclipsing nova-like cataclysmic variable EC 21178−5417 obtained between 2002 and 2013. The average spectrum of EC 21178−5417 shows broad double-peaked emission lines from He ii 4686 Å (strongest feature) and the Balmer series. The high-excitation feature, C iii/N iii at 4640–4650 Å, is also present and appears broad in emission. A number of other lines, mostly He i, are clearly present in absorption and/or emission. The average spectrum of EC 21178−5417 taken at different months and years shows variability in spectral features, especially in the Balmer lines beyond Hγ, from pure line emission, mixed line absorption, and emission to pure absorption lines. Doppler maps of the He ii 4686 Å emission reveal the presence of a highly inclined asymmetric accretion disc and a two spiral arm-like structure, whereas that of the Balmer lines (Hα and Hβ) reveal a more circular accretion disc. There is no evidence of a bright-spot in the Doppler maps of EC 21178−5417 and no emission from the secondary star is seen in the tomograms of the He ii 4686 Å and Balmer lines. Generally, the emission in EC 21178−5417 is dominated by emission from the accretion disc. We conclude that EC 21178−5417 is a member of the RW Tri or UX UMa subtype of nova-like variables based on these results and because it shows different spectral characteristics at different dates. This spectral behaviour suggests that EC 21178−5417 undergoes distinct variations in mass transfer rate on the observed time-scales of months and years.

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48

Ofengeim, Dmitry, and Dmitry Zyuzin. "Thermal Spectrum and Neutrino Cooling Rate of the Vela Pulsar." Particles 1, no. 1 (July 30, 2018): 14. http://dx.doi.org/10.3390/particles1010014.

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We reanalyse the X-ray spectrum of the PSR B0833–45 (the Vela pulsar) using the data of the Chandra space observatory. In contrast to previous works, we consider a wide range of possible masses and radii of the pulsar. The derived surface temperature of the star Ts∞=0.66−0.01+0.04MK (1σ level over the entire mass and radius range of our study) is consistent with earlier results. However, the preferable values of Vela’s mass and radius given by the spectral analysis are different from those used previously; they are consistent with modern equation of state models of neutron star matter. In addition, we evaluate the Vela’s surface temperature as a function of assumed values of its mass and radius. This allows us to analyse the neutrino cooling rates consistent with the evaluated surface temperatures and explore the additional restrictions that could be set on the Vela’s mass and radius using different versions of the neutron star cooling theory.

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49

Chen, Jonathan H. K., Vincent C. C. Cheng, Chun-Pong Wong, Sally C. Y. Wong, Wing-Cheong Yam, and Kwok-Yung Yuen. "Rapid Differentiation of Haemophilus influenzae and Haemophilus haemolyticus by Use of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry with ClinProTools Mass Spectrum Analysis." Journal of Clinical Microbiology 55, no. 9 (June 21, 2017): 2679–85. http://dx.doi.org/10.1128/jcm.00267-17.

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ABSTRACT Haemophilus influenzae is associated with severe invasive disease, while Haemophilus haemolyticus is considered part of the commensal flora in the human respiratory tract. Although the addition of a custom mass spectrum library into the matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) system could improve identification of these two species, the establishment of such a custom database is technically complicated and requires a large amount of resources, which most clinical laboratories cannot afford. In this study, we developed a mass spectrum analysis model with 7 mass peak biomarkers for the identification of H. influenzae and H. haemolyticus using the ClinProTools software. We evaluated the diagnostic performance of this model using 408 H. influenzae and H. haemolyticus isolates from clinical respiratory specimens from 363 hospitalized patients and compared the identification results with those obtained with the Bruker IVD MALDI Biotyper. The IVD MALDI Biotyper identified only 86.9% of H. influenzae (311/358) and 98.0% of H. haemolyticus (49/50) clinical isolates to the species level. In comparison, the ClinProTools mass spectrum model could identify 100% of H. influenzae (358/358) and H. haemolyticus (50/50) clinical strains to the species level and significantly improved the species identification rate (McNemar's test, P < 0.0001). In conclusion, the use of ClinProTools demonstrated an alternative way for users lacking special expertise in mass spectrometry to handle closely related bacterial species when the proprietary spectrum library failed. This approach should be useful for the differentiation of other closely related bacterial species.

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50

Zhong, You Qun, Xiang Qun Xu, Jie Yang, and Ling Cheng. "Study on Active Compounds of Apocynum venetum L." Applied Mechanics and Materials 496-500 (January 2014): 163–66. http://dx.doi.org/10.4028/www.scientific.net/amm.496-500.163.

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Although Apocynum leaves have been used for the treatment of cardiovascular diseases, the study on active compounds of Apocynum venetum L. is little. In this paper,high performance liquid chromatography with mass spectrometry (HPLC-MS) were used for the active ingredient in qualitative analysis of Apocynum leaves, based on the information of the mass spectrum molecular ion peak [M-and some characteristic fragment ions, and combined with UV spectral characteristics we initially speculated that Apocynum leaves water extract isolated to 10 components.

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