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Asymmetry ratio as a parameter of Eu^3＋ local environment in phosphors

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Journal of Rare Earths 2018年第5期36卷 474-481页

作者： Ilya E. Kolesnikov Alexey v. Povolotskiy daria v. Mamonova Evgeny Yu. Kolesnikov Alexey v. Kurochkin Erkki Lahderanta Mikhail D. Mikhailov Saint Petersburg State University 7/9 Universitetskaya nab. 199034 St.petersburg.Russia Lappeenranta University of Technology LUT Skinnarilankatu 34 53850 Lappeenranta Finland Scientific and Technological Institute of Optical Material Science VNTs S. I. Vavilov State Optical Institute Babushkina 36-1 192171 St. Petersburg Russia volga State University of Technology Lenin Sq. 3 424000 Yoshkar-Ola Russia

Study of the local environment of certain ion is quite a complex problem. Due to the unique luminescent properties, Eu^3＋ ions can be used as a structural probe. In this paper, effect of doping concentration,excitation wavelength and excitation mechanism on asymmetry ratio was systematically studied using Y3Al5O12：Eu^3＋, YvO4：Eu^3＋ and Y2O3：Eu^3＋nanophosphors. The asymmetry ratio gives information about the local surrounding and environmental changes around the Eu^3＋ ions. Asymmetry ratios of YAG：Eu^3＋and YvO4：Eu^3＋ nanopowders were calculated using standard technique and the obtained average values were found to be 0.75 and 8.2, respectively. However, it is found that standard method of asymmetry ratio calculation is suitable only for samples where all Eu^3＋ ions occupy one site. The ＂multisite model＂ of asymmetry ratio calculation was developed and used for Y2O3：Eu^3＋ nanocrystalline powders. Average value of asymmetry ratio for Eu^3＋ ions occupied ＂normal＂ sites is 6.0 and for Eu^3＋ ions occupied ＂defect＂sites is 2.3.

关键词： Eu3+ Oxide powders Luminescence Asymmetry ratio Structural probe Rare earths

Hot spots of DNA double-strand breaks and genomic contacts of human rDNA units are involved in epigenetic regulation

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分子细胞生物学报:英文版 2015年第4期7卷 366-382页

作者： Nickolai A.Tchurikov daria M.Fedoseeva Dmitri v.Sosin Anastasia v.Snezhkina Nataliya v.Melnikova Anna v.Kudryavtseva Yuri v.Kravatsky Olga v.Kretova Department of Epigenetic Mechanisms of Gene Expression Regulation Engelhardt Institute of Molecular BiologyMoscow 119334Russia Group of Postgenomic Studies Engelhardt Institute of Molecular BiologyMoscow 119334Russia Laboratory of DNA-Protein Interactions Engelhardt Institute of Molecular BiologyMoscow 119334Russia

DNA double-strand breaks(DSBs)are involved in many cellular mechanisms,including replication,transcription,and genome *** recent observation that hot spots of DSBs in human chromosomes delimit DNA domains that possess coordinately expressed genes suggests a strong relationship between the organization of transcription patterns and hot spots of *** this study,we performed mapping of hot spots of DSBs in a human 43-kb ribosomal DNA(rDNA)repeated *** observed that rDNA units corresponded to the most fragile sites in human chromosomes and that these units possessed at least nine specific regions containing clusters of extremely frequently occurring DSBs,which were located exclusively in non-coding intergenic spacer(IGS)*** hot spots of DSBs corresponded to only a specific subset of DNase-hypersensitive sites,and coincided with CTCF,PARP1,and HNRNPA2B1 binding sites,and H3K4me3 *** rDNA-4C data indicate that the regions of IGS containing the hot spots of DSBs often form contacts with specific regions in different chromosomes,including the pericentromeric regions,as well as regions that are characterized by H3K27ac and H3K4me3 marks,CTCF binding sites,ChIA-PET and RIP signals,and high levels of *** data suggest a strong link between chromosome breakage and several different mechanisms of epigenetic regulation of gene expression.

关键词： double-strand breaks fragile sites rDNA IGS PARP1 HNRNPA2B1 4C

Graphene and other two-dimensional materials

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Frontiers of physics 2019年第1期14卷 1-4页

作者： Kostya S. Novoselov daria v. Andreeva Wencai Ren Guangcun Shan School of Physics and Astronomy University of Manchester Manchester M13 9PL United Kingdom National Graphene Institute University of Manchester Manchester M13 9PL United Kingdom Centre for Advanced 2D Materials and Graphene Research Centre National University of Singapore 6 Science Drive 2 117546 Singapore Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China School of Instrumentation Science and Opto-electronics Engineering Beihang University Beijing 100191 China

Over the last few years,research on graphene [1-3]has progressed significantly,and as a result,a number of reallife applications of graphene have been realized [4,5].This carbon allotrope (for a review on other forms of carbon, see [6])resulted in a number of novel physical phenomena already discovered (ranging from new types of quantum Hall effect to universal optical conductivity)and dramatically expanded the range of possible applications for such materials (from transparent conductive coating to ultrafast photodetectors).

关键词： Graphene two-dimensional materials universal optical conductivity

Extracellular vesicles in the diagnosis and treatment of central nervous system diseases

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Neural Regeneration Research 2020年第4期15卷 586-596页

作者： Alisa A.Shaimardanova valeriya v.Solovyeva daria S.Chulpanova victoria James Kristina v.Kitaeva Albert A.Rizvanov Institute of Fundamental Medicine and Biology Kazan Federal UniversityKazanRussia Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry The Russian Academy of SciencesMoscowRussia School of veterinary Medicine and Science University of NottinghamSutton Bonington CampusLeicestershireUK

Extracellular vesicles,including exosomes and microvesicles,play a fundamental role in the activity of the nervous system,participating in signal transmission between neurons and providing the interaction of central nervous system with all body *** many neurodegenerative diseases,neurons pack toxic substances into vesicles and release them into the extracellular space,which leads to the spread of misfolded neurotoxic *** contents of neuron-derived extracellular vesicles may indicate pathological changes in the central nervous system,and the analysis of extracellular vesicle molecular content contributes to the development of non-invasive methods for the diagnosis of many central nervous system *** vesicles of neuronal origin can be isolated from various biological fluids due to their ability to cross the blood-brain ***,the diagnostic potential of almost all toxic proteins involved in nervous system disease pathogenesis,specificallyα-synuclein,tau protein,superoxide dismutase 1,FUS,leucine-rich repeat kinase 2,as well as some synaptic proteins,has been well *** attention is paid to extracellular RNAs mostly associated with extracellular vesicles,which are important in the onset and development of many neurodegenerative *** on parental cell type,extracellular vesicles may have different therapeutic properties,including neuroprotective,regenerative,and *** to nano size,biosafety,ability to cross the blood-brain barrier,possibility of targeted delivery and the lack of an immune response,extracellular vesicles are a promising vehicle for the delivery of therapeutic substances for the treatment of neurodegenerative diseases and drug delivery to the *** review describes modern approaches of diagnosis and treatment of central nervous system diseases using extracellular vesicles.

关键词： biomarkers cell-mediated therapy central nervous system diseases diagnosis exosomes extracellular RNAs extracellular vesicles microRNAs microvesicles neurodegenerative diseases

PCR-HRM for Genomic Surveillance of SARS-Cov-2: A variant Detection Tool in Côte d’Ivoire, West Africa

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American Journal of Molecular Biology 2024年第3期14卷 166-185页

作者： Aboubacar Sylla Solange Kakou-Ngazoa Tata Gniré Safiatou Coulibaly Yakoura Karidja Ouattara Mireille Sylvie Kouamé-sina Zeinab Ouattara David Ngolo Coulibaly Brice Kouakou Bla Mireille Dosso Molecular Biology Platform Pasteur Institute Cte dIvoire Abidjan Cte dIvoire Laboratory of Biology and Health UFR Biosciences University Flix Houphout Boigny Abidjan Cte dIvoire Genetic and Cancer Laboratory Molecular Genetics Platform Pasteur Institute Cte dIvoire Abidjan Cte dIvoire Epidemic virus Department Pasteur Institute Cte dIvoire Abidjan Cte dIvoire

The rise of new viruses, like SARS-Cov-2 causing the COvID-19 outbreak, along with the return of antibiotic resistance in harmful bacteria, demands a swift and efficient reaction to safeguard the health and welfare of the global population. It is crucial to have effective measures for prevention, intervention, and monitoring in place to address these evolving and recurring risks, ensuring public health and international security. In countries with limited resources, utilizing recombinant mutation plasmid technology in conjunction with PCR-HRM could help differentiate the existence of novel variants. cDNA synthesis was carried out on 8 nasopharyngeal samples following viral RNA extraction. The P1 segment of the SARS-Cov-2 Spike S protein was amplified via conventional PCR. Subsequently, PCR products were ligated with the pGEM-T Easy vector to generate eight recombinant SARS-Cov-2 plasmids. Clones containing mutations were sequenced using Sanger sequencing and analyzed through PCR-HRM. The P1 segment of the S gene from SARS-Cov-2 was successfully amplified, resulting in 8 recombinant plasmids generated from the 231 bp fragment. PCR-HRM analysis of these recombinant plasmids differentiated three variations within the SARS-Cov-2 plasmid population, each displaying distinct melting temperatures. Sanger sequencing identified mutations A112C, G113T, A114G, G214T, and G216C on the P1 segment, validating the PCR-HRM findings of the variations. These mutations led to the detection of L452R or L452M and F486v protein mutations within the protein sequence of the Omicron variant of SARS-Cov-2. In summary, PCR-HRM is a vital and affordable tool for distinguishing SARS-Cov-2 variants utilizing recombinant plasmids as controls.

关键词： Genomic Surveillance SARS-Cov-2 PCR-HRM variants Côte d’Ivoire

Third-Order Optical Nonlinearity in Two-Dimensional Transition Metal Dichalcogenides

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Communications in Theoretical Physics 2018年第9期69卷 344-360页

作者： sina Khorasani School of Electrical Engineering Sharif University of Technology Tehran lran Ecole Polyteehnique F6d6rale de Lausanne CH-1015 Lausanne Switzerlan

We present a detailed calculation of the linear and nonlinear optical response of four types of monolayer twodimensional (2D) transition-metal dichalcogenides (TMDCs), having the formula MX2 with M=Mo, W and X=S, *** calculations are based on 6-band tight-binding model of TMDCs, and then performing a semi-classical perturbation analysis of response functions. We numerically calculate the linearχ(1)μν(-ω;ω) and nonlinear surface susceptibility tensorsχ(3)μνζη(-ωΣ;ωr,ωs,ωt) withωΣ=ωr+ωs+ωt. Both non-degenerate and degenerate cases are studied for thirdharmonic generation and nonlinear refractive index, respectively. Computational results obtained with no external fitting parameters are discussed regarding two recent reported experiments on Mo S2, and thus we can confirm the extraordinarily strong optical nonlinearity of TMDCs. As a possible application, we demonstrate generation of aπ/4-rotated squeezed state by means of nonlinear response of TMDCs, in a silica micro-disk resonator covered with the 2D material. Our proposed method will enable accurate calculations of nonlinear optical response, such as four-wave mixing and highharmonic generation in 2D materials and their heterostructures, thus enabling study of novel functionalities of 2D photonic integrated circuits.

关键词： 2D materials nonlinear optics transition metal dichalcogenides quantum optics

Functionality of a bicistronic construction containing HEXA and HEXB genes encoding β-hexosaminidase A for cell-mediated therapy of GM2 gangliosidoses

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Neural Regeneration Research 2022年第1期17卷 122-129页

作者： Alisa A.Shaimardanova daria S.Chulpanova valeriya v.Solovyeva Aleksandr M.Aimaletdinov Albert A.Rizvanov Institute of Fundamental Medicine and Biology Kazan Federal UniversityKazanRussia

Tay-Sachs disease and Sandhoff disease are severe hereditary neurodegenerative disorders caused by a deficiency ofβ-hexosaminidase A(HexA)enzyme,which results in the accumulation of GM2 gangliosides in the nervous system *** this work,we analyzed the efficacy and safety of cell-mediated gene therapy for Sandhoff disease and Sandhoff disease using a bicistronic lentiviral vector encoding cDNA of HexAα-andβ-subunit genes separated by the nucleotide sequence of a P2A peptide(HEXA-HEXB).The functionality of the bicistronic construct containing the HEXA-HEXB genetic cassette was analyzed in a culture of HEK293T cells and human umbilical cord blood mononuclear cells(hUCBMCs).Our results showed that the enzymatic activity of HexA in the conditioned medium harvested from genetically modified HEK293T-HEXA-HEXB and hUCBMCs-HEXA-HEXB was increased by 23 and 8 times,respectively,compared with the conditioned medium of native *** blot analysis showed that hUCBMCs-HEXA-HEXB secreted both completely separated HEXA and HEXB proteins,and an uncleaved protein containing HEXA+HEXB linked by the P2A *** injection of genetically modified hUCBMCs-HEXA-HEXB to laboratory Wistar rats was carried out,and the HexA enzymatic activity in the blood plasma of experimental animals,as well as the number of live cells of immune system organs(spleen,thymus,bone marrow,lymph nodes)were determined.A significant increase in the enzymatic activity of HexA in the blood plasma of laboratory rats on days 6 and 9(by 2.5 and 3 times,respectively)after the administration of hUCBMCsHEXA-HEXB was *** the same time,the number of live cells in the studied organs remained ***,the functionality of the bicistronic genetic construct encoding cDNA of the HEXA and HEXB genes separated by the nucleotide sequence of the P2A peptide was shown in vitro and in *** hypothesize that due to the natural ability of hUCBMCs to overcome biological barriers,such a strategy can rest

关键词： bicistronic vector cell-mediated gene therapy GM2 gangliosidosis P2A peptide Sandhoff disease Tay-Sachs disease umbilical cord blood mononuclear cells β-hexosaminidase

Thermodynamic Evaluation of Mineral Balance in Water Thickness of the Soda Lake Doroninskoe(Eastern Transbaikalia,Russia)

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Acta Geologica Sinica(English Edition) 2014年第S1期88卷 123-124页

作者： Svetlana v.BORZENKO Leonid v.ZAMANA daria S.SUvOROvA Institute of Natural Resources Cryology and Ecology Siberian Branch of RAS Institute of the Earth's Crust Siberian Branch of RAS

In recent years,lakes,including salted,attract the attention of researchers,also when reconstructing last climate changes using the bottom sediments(Solotchina et al.,2008,et al.).In this case the different geochemical

关键词： Thermodynamic Evaluation of Mineral Balance in Water Thickness of the Soda Lake Doroninskoe Eastern Transbaikalia,Russia

Quantification of glucose and glycerol diffusion in myocardium

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Journal of Innovative Optical Health Sciences 2015年第3期8卷 46-55页

作者： daria K.Tuchina Alexey N.Bashkatov Elina A.Genina valery v.Tuchin Research-Educational Institute of Optics and Biophotonics Saratov State University Saratov 410012Russia Laboratory of Laser Diagnostics of Technical and Living Systems Institute of Precise Mechanics and Control RAS Saratov 410028 Russia Optoelectronics and Measurement Techniques Laboratory P.O.Box 4500 University of Oulu FIN-90014OuluFinland

The results on determination of glucose and glycerol difusion cofficients in myocardium tissuse are *** method is based on the measurement and analysis of temporal dependence of tissue optical collimated transmittance umder action of a hyperosmotic *** temporal tissue response is related to the rate of the agent and water diffusion in a *** diffusion coefficients for tssue fAuid fluxes at glucose and glycerol application to the myocardium at 20℃ have been estimated as(4.75±3.40)×10^(-7) and(7.71±4.63)×10^(-7) cm^(2)/s,respectively.

关键词： Difusion cofficient optical clearing delhydration scattering.