Analitika i Kontrol最新文献

{"title":"Differentiation of oil samples by isomeric composition of paraffins using cluster analysis methods","authors":"Iu. P. Turov, M. I. Guzniaeva","doi":"10.15826/analitika.2022.26.1.006","DOIUrl":"https://doi.org/10.15826/analitika.2022.26.1.006","url":null,"abstract":"A new method is proposed for controlling the sources of oil samples by chemical composition for their differentiation, identification and establishment of their origin (specific wells of the operating field) using the agglomerative hierarchical data clustering and applying the J. Ward algorithm. The initial information is the data on the composition and relative contents of n-paraffins С17Н36 ÷ С34Н70, isoprenoids of pristane С19Н40 and phytane С20Н42 in oil samples obtained by selected-ion monitoring gas chromatography/mass spectrometry. The solution to the problem was carried out in the absence of the information about the magnitude of the total uncertainty in the data, without using the standard samples for their assessment and without the preliminary assumption of the number of expected clusters. The proposed technique’s possibilities were illustrated by the results of 20 × 27 data matrix processing based on the relative paraffin content in 27 encrypted anonymous samples. As an outcome, three clusters were identified, each of which included objects sampled from the specific well. Differentiating the sources of the samples using the traditional methods by comparing the amounts of n-paraffins and isoprenoids proved to be impossible. Due to the inevitable errors in the analysis results and the possible changes in the composition of the recovered oil, the values of the relative contents of paraffins in the oil samples from all three wells overlap and the sources remain indistinguishable. The newly proposed method made it possible to solve the differentiation problem of oil samples in organic geochemistry and environment control which are complicated by the wide variability of the composition of oil samples, the lability of petroleum system under the influence of natural and technogenic factors and the absence of the estimate of the actual errors in the data.","PeriodicalId":37743,"journal":{"name":"Analitika i Kontrol","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67254666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Book review for “X-Ray Fluorescence in Biological Sciences: Principles, Instrumentation, and Applications”, Eds: V.K. Singh, J. Kawai, D.K. Tripathi. Wiley. 2022, 688 pp. ISBN: 978-1-119-64554-2A","authors":"A. G. Revenko","doi":"10.15826/analitika.2022.26.2.006","DOIUrl":"https://doi.org/10.15826/analitika.2022.26.2.006","url":null,"abstract":"Through the efforts of three editors - V.K. Singh and D.K. Tripathi (India), and J. Kawai (Japan), as well as 79 qualified specialists from 14 countries, “X-ray Fluorescence in Biological Sciences: Principles, Instrumentation and Applications” monograph was prepared and published in March of this year. The book is divided into six parts. Part 1 is a general introduction to RFA (7 chapters). Parts 2 and 3 are relatively new versions of the XRF method using the synchrotron radiation for the excitation of fluorescence (5 chapters) and XRF with total external reflection (4 chapters). Part 4, a beginner's guide, is considered by the editors to be one of the highlights of this book (4 chapters). The main parts of this book are Parts 5 (Application for Biological Samples - 11 chapters) and 6 (Special Topics and Comparison with Other Methods - 8 chapters). The book provides information on advances in the application of X-ray fluorescence analysis that have not been reflected in general monographs published in recent years. Representatives of India prepared 15 chapters, colleagues from Russia – 7, from Mongolia and China – 3 each, Japan, Spain, Turkey and Slovenia – with 2 chapters each, Italy, Argentina, and Bangladesh – 1 each. Representatives of Algeria and Egypt co-authored with colleagues from Turkey, and of South Korea with colleagues from India, respectively. The largest number of participants (authors of chapters) – 29 – was noted for India, 11 – from Russia, and 6 each from China, Turkey, and Slovenia. The monograph will be in demand in the laboratories of universities and research institutes, especially in the laboratories of biological and medical research centers. It will be a useful guide for students of natural and chemical sciences, medical biology, plant physiology, and agriculture.","PeriodicalId":37743,"journal":{"name":"Analitika i Kontrol","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67255039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electrochemical sensor modified with gold and arenediazonium salts for the determination of copper and mercury in human’s hair","authors":"G. Slepchenko, M. S. Ostapenko, Yu. A. Akeneev, E. S. Moiseeva","doi":"10.15826/analitika.2022.26.2.004","DOIUrl":"https://doi.org/10.15826/analitika.2022.26.2.004","url":null,"abstract":"Current article presents the results of using a solid carbon-containing electrochemical sensor modified with arenediazonium salts (ME-ADT-COOH) for the joint determination of copper and mercury in human hair. The sensitivity of the determination of copper and mercury ions using a graphite electrode modified with gold and arenediazonium salts with a substituent carboxy group is higher compared to the other carbon-containing modified electrodes. The influence of the concentration of arenediazonium tosylates with various substituents on the obtained analytical signal was studied. The conditions for the manufacturing the new carbon-containing modified electrochemical sensor have been developed. The effective surface area of the modified electrode was calculated, which was estimated using a cyclic voltammogram against the background of 0.1 M KCl with the addition of potassium hexacyanoferrate (С=5*10-4mol/l) salts and calculated using the Randles-Ševčík equation for the reversible electrode process. A linear range of determined concentrations in the voltametric determination of microelements on the arendiazonium-modified gold-graphite electrode was established - from 0.1 to 12 µg/g. The error of the determination did not exceed 25 %. The correctness of the results of the determination of copper and mercury in real objects by the “introduced-found” method, which correlates well with the known values, has been verified.","PeriodicalId":37743,"journal":{"name":"Analitika i Kontrol","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67255272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spectrophotometric determination of phenylalanine in aqueous solutions with different acidity","authors":"V. Vasil'eva, A. Saud","doi":"10.15826/analitika.2022.26.3.003","DOIUrl":"https://doi.org/10.15826/analitika.2022.26.3.003","url":null,"abstract":"A method for the determination of phenylalanine using the spectrophotometric method without preliminary correction of the solutions pH and the use of auxiliary chemical reagents has been developed. A comparative analysis of the spectrophotometric determination of phenylalanine by varying acidity of the medium was carried out. The errors and the possibility of their minimization were analyzed. It was shown that the analytical signal and the results of amino acid determination in the solutions with different pH differ significantly due to the presence of phenylalanine in various ionic forms that vary in the magnitude of the molar absorption coefficient. It was found that the maximum value of the molar absorption coefficient decreases in the series ε(Phe−)> ε(Phe+)> ε(Phe±) by 20%. The maximum error in determining the phenylalanine concentration without taking into account the dependence of the optical density of the solution on the acidity of the medium was found in strongly alkaline solutions. The correlation dependences of the analytical wavelength and molar absorption coefficient of phenylalanine on the pH of the medium were obtained experimentally. A long-wavelength (bathochromic) shift of the absorption band maximum was established upon the transition from positive to negative charge of the phenylalanine molecule with increasing pH of the solution. Two ranges of pH values have been identified, in which a change in the acidity of the solutions did not cause spectral changes. These were the regions where the amino acid was predominantly found in cationic Phe+ and bipolar Phe± forms (pH < 8) and in the region of anionic Phe− (pH > 10) form. The regression equations that allow choosing the analytical wavelength at any arbitrary pH of the solution were presented. The advantage of the developed approach is the possibility of increasing the detection sensitivity and ensuring that the error in the amino acid determination in the solutions of arbitrary acidity is less than 0.5% with the variation of no more than 0.3%. The detection limit of amino acid, calculated by 3σ – test, is (1.4 − 1.6) × 10-5 M. The range of the determined phenylalanine contents is (0.5 − 5.3) × 10-3 M. The efficiency of the proposed approach for determining the content of phenylalanine in a sample of the \"L-Phenylalanine\" (Protein Company, Russia) drug by the method of standard addition was shown. The possibility of minimizing the error in determining the amino acid when applying the technique to control the content of components in the process of demineralization of water-salt solutions of phenylalanine by electrodialysis with experimental membranes has been proven.","PeriodicalId":37743,"journal":{"name":"Analitika i Kontrol","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67255467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fluorescence of anisotropic primary X-ray radiation","authors":"B. I. Kitov","doi":"10.15826/analitika.2022.26.1.002","DOIUrl":"https://doi.org/10.15826/analitika.2022.26.1.002","url":null,"abstract":"In the X-ray spectral fluorescence analysis, the anisotropy of primary radiation results in an uneven radiation of a sample’s surface, strengthening the role of some sections and weakening the role of others. The goal of the current work was to determine the minimal distance from the window of the X-ray tube with a cone-shaped anode at which the intensity of the sample’s radiation becomes homogeneous. The research method was the computer modeling of the X-ray fluorescence experiment. The working model was built on the basis of two equations for the densities of the fluxes of braking and characteristic radiations of the massive anode, which took into account the absorption of primary radiation by the anode’s material and the back-scattering of electrons. The ring source was represented in the model as the sum of infinitely small linear elements of equal power, and the sample was disc-shaped and coaxial with the source. The calculation diagram was very well consistent with the experimental diagram of radiation’s direction described in the research literature. Two spatial distributions were calculated. The first one described the distribution of primary radiation’s intensity on the surface of the sample, while the second one described the distribution of the fluorescent radiation, which was more valuable for the X-ray spectrometry. The calculations showed that although the second distribution, unlike the first one, considered the absorption of the primary radiation and secondary radiation in the sample, the shapes of both radiations were close. It was demonstrated that the area of the sample, which carried the most information on the composition of the irradiated material, was ring-shaped, and the width of this ring depended on the distance to the X-ray tube’s window. As the distance increased, the diagram of the spatial distribution of the radiation’s intensity became smoother, and, when the distance exceeded two diameters of the anode, the radiation became homogeneous. The constructed model, which considered the anisotropy of the primary analysis, could be applied in the method of fundamental parameters of X-ray fluorescence analysis for a spectrometer with compressed geometry.","PeriodicalId":37743,"journal":{"name":"Analitika i Kontrol","volume":"118 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67254098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Selection of the parameters of a multicapillary column for portable gas analyzers by Kovach indices","authors":"A. P. Efimenko, I. Naumenko, E. V. Kirillova, A. Shorokhov","doi":"10.15826/analitika.2022.26.1.003","DOIUrl":"https://doi.org/10.15826/analitika.2022.26.1.003","url":null,"abstract":"Short straight multicapillary columns (MCC) allow for fast gas chromatographic separation. However, their limited efficiency makes it difficult to use them for the analysis of multicomponent mixtures. Therefore, it is important to preliminarily evaluate the possibility of separation of target substances, based on the available information about their characteristics, in particular, by retention indices (RI). The paper provides an example of the choice of MCC and chromatographic conditions for the separation of explosives in stationary phases OV-5 and SE-54. To find the correspondence of the retention indices of the target substances with their retention factors k on the studied MCCs, the retention times of C10−C19 n-alkanes were experimentally determined at different column temperatures. Then the dependences of the calculated lnk on the quantity of carbon atoms m in n-alkanes CmH2m+2 were plotted and approximated by linear functions ln k = a + bm and their coefficients a and b were found for each temperature. From where, it was easy to calculate the retention factors of the target substances by their RI, assuming that RI = m·100, as well as to estimate the MCC efficiency required to separate neighboring peaks to obtain the desired level of separation. Based on the obtained equations, the explosives retention factors for MCCs at different temperatures were calculated and their required efficiency for separating adjacent peaks was estimated. The retention factors experimentally determined for some explosives on the MCCs at 140 °C turned out to be quite close to the theoretically calculated ones. In the future, the similar approach can be used to predict the possibility of gas chromatographic separation of mixtures of dangerous substances such as narcotic drugs.","PeriodicalId":37743,"journal":{"name":"Analitika i Kontrol","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67254205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"AMPEROMETRIC IMMUNOSENSORS BASED ON CARBON NANOMATERIALS AND RHENIUM CLUSTERS FOR THE DETERMINATION OF TRICYCLIC ANTIDEPRESSANTS IN A SEQUENTIAL INJECTION SYSTEM","authors":"E. P. Medyantseva, E. R. Gazizullina, D. Brusnitsyn, A. Dobrynin, K. Brylev, A. Mustafina, J. Elistratova","doi":"10.15826/analitika.2022.26.4.002","DOIUrl":"https://doi.org/10.15826/analitika.2022.26.4.002","url":null,"abstract":"A method of sequential injection determination of tricyclic antidepressants (amitriptyline, desipramine, imipramine) using amperometric immunosensors based on screen-printed graphite electrodes modified by carbon nanomaterials (carbon nanotubes, graphene oxide or fullerene) in combination with hexarhenium chalcogenide clusters is proposed. Sequential injection analysis was performed at a sweep rate of 10 mV/s; the flow rate (supporting electrolyte – phosphate buffer solution with pH 7.0) was also varied from 20 to 40 µl/s. Composition of the modifier affects the analytical capability of immunosensors. Screening of various types of modifiers showed that the immunosensor based on graphene oxide and cyanide complexes of rhenium chalcogenide clusters exhibited the highest sensitivity of 23.9±0.9 with a range of working concentrations of 1·10–10–1·10–5 M, and even wider range of detectable concentrations, 1·10–10–1·10–4 M was observed for the immunosensor based on fullerene and cyanide complexes of rhenium chalcogenide clusters. The lowest limit of the determined contents was (4–7)·10–11 M. Relative standard deviation of repeatability (Sr) did not exceed 0.046. The results obtained show that the proposed immunosensors can be used in sequential injection determination of trace amounts of medicinal compounds (antidepressants) in biomedical objects.","PeriodicalId":37743,"journal":{"name":"Analitika i Kontrol","volume":"32 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67255017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Book review for a book by M. Haschke, J. Flock, M. Haller “Laboratory Applications of X-ray Fluorescence”, Wiley. 2021, 464 pp., 263 illustrations.","authors":"A. G. Revenko","doi":"10.15826/analitika.2022.26.1.008","DOIUrl":"https://doi.org/10.15826/analitika.2022.26.1.008","url":null,"abstract":"The use of X-ray fluorescence analysis (XRF) has been constantly expanding in recent years. The number of users without special training is increasing. This paper provides information on the monograph by M. Haschke, J. Flock, and M. Haller “Laboratory Applications of X-ray Fluorescence”. The book was published by Wiley-VCH. The book under review was written by experts with extensive experience in XRF. The authors made a significant contribution to the development of X-ray fluorescence analysis. The book consists of a Preface, a List of abbreviations and symbols, Information about authors, an Introduction, 18 Chapters, two Appendixs (A - Tables, B - Important information), a References and an Index. The material of the book in the review is discussed chapter by chapter. The book presents various sample preparation procedures that are typical for XRF and discusses their impact on the precision and accuracy of the analysis. The main types of X-ray spectrometers, as well as the design, construction and features of the operation of individual components of the devices are considered. The main techniques for measuring and evaluating X-ray spectra are discussed, and the metrological characteristics of XRF are compared with other analytical methods. In full accordance with the title of the book, the authors paid the main attention to the discussion of options for solving various analytical problems using XRF. Homogeneous and heterogeneous, solid and liquid materials, application in geology, ecology, biology, industrial enterprises, research laboratories in the study of objects of heritage are considered. It should be noted the presence in the book of the Appendix “Important information”. Prepared by the authors, a modern high quality reference guide will be useful for both beginners and qualified professionals. A clear presentation of the material allows us to recommend it as a teaching aid for students and undergraduates. It seems that the book will be in demand in the laboratories of research institutes and universities, as well as in the laboratories of industrial enterprises.","PeriodicalId":37743,"journal":{"name":"Analitika i Kontrol","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67254877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The use of NIR Fluorimetry with photographic data acquisition in the fingerprinting method with the addition of fluorophores to the samples: discrimination of apple juices","authors":"E. Skorobogatov, I. Stepanova, V. S. Orekhov, M. Beklemishev","doi":"10.15826/analitika.2022.26.1.005","DOIUrl":"https://doi.org/10.15826/analitika.2022.26.1.005","url":null,"abstract":"The application of dyes, that fluoresce in the near infrared (NIR, 700-800 nm) region, for the recognition of samples using a fingerprinting method with the addition of fluorophores to the samples (“fluorescent eye”) is proposed. The technique has been successfully applied to the classification of samples of various nature. In the current work, this strategy has been tested on the example of discrimination of 17 samples of apple juice from different manufacturers, purchased at different times. An indolenine series heptamethine carbocyanine dye in the presence of surfactants was used as the added fluorophore, red LEDs were used as an excitation source, and the signal was recorded using a digital camera with an additional IR filter installed; a spectrofluorimeter with a 96-well plate accessory was used to record the spectra. Photographic images were processed using Unscrambler X and Excel software. The results were presented using the following coordinates: intensity of NIR fluorescence - intensity of visible light reflection (using the photographic images). It was found that such presentation allowed the samples to be divided into groups associated with the manufacturer. We have also obtained intrinsic fluorescence spectra, including those with the addition of NIR dye, and these results were processed by the principal component analysis. It was possible to distinguish 5–6 groups of samples by their intrinsic emission, not counting the blank, while the spectra with the addition of the dye allowed to isolate the largest number of groups of samples (9). At the same time, the classification using spectra did not allow juices to be grouped by the producer. Also, obtaining photographs using a visualizer was easier and faster than recording the fluorescence spectra. The joint processing of emission spectra and photographs did not improve the quality of discrimination.","PeriodicalId":37743,"journal":{"name":"Analitika i Kontrol","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67254908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Decreasing the uncertainty of gas chromatographic quantification using the solvent’s signal in the method of external standard","authors":"I. Zenkevich, S. V. Byvsheva, A. Gerasimov, S. Gladnev, M. V. Grigoriev, N. Gubina, E. Didenko, A. S. Kazantsev, T. D. Kalutskaia, E. V. Katernuk, A. Koblova, D. V. Krutin, K. P. Malkova, S. A. Metliaeva, V. S. Odegova, D. S. Smirnova, V. Spivakovskyi, P. Terno","doi":"10.15826/analitika.2022.26.2.005","DOIUrl":"https://doi.org/10.15826/analitika.2022.26.2.005","url":null,"abstract":"Uncertainties of the results of quantitative determinations in gas chromatography using the methods based on the absolute peak areas (including the external standard method) are rather “sensitive” to the reproducibility of injections. The effective way to compensate for such errors is to introduce the additional standards into the samples, followed by replacing the absolute peak areas by their ratios to peak areas of the standards. It is important to underline that any constituents of the samples can be used as additional standards, including the solvents. Solvents can be used for these purposes even if the heights of their peaks are restric­ted when the analytical signals exceed the amplifier limits. Using the relative peak areas does not require any extra sample processing besides the registration of peak areas for solvents. Comparing the commonly known and modified methods of external stan­dard demonstrates that using the relative peak areas instead of the absolute ones does not influence the overall precision of determinations (according to the criterion “intro­duced-determined”) but improve the reproducibility by 2-3 times. The problem of increasing the reliability of such statistical evaluations of results is discussed and to solve it, it is proposed to change the “design” of the experiments. Instead of series of successive analyses of similar origin samples, the use of parallel determinations is preferable. This can be realized, for example, during the fulfillment of student’s practical works.","PeriodicalId":37743,"journal":{"name":"Analitika i Kontrol","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67255345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}