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| 2. |
- Bibikova, E. V., et al.
(author)
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Sarmatia-Volgo-Uralia junction zone: Isotopic-geochronologic characteristic of supracrustal rocks and granitoids
- 2009
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In: Stratigraphy and Geological Correlation. - 0869-5938. ; 17:6, s. 561-573
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Journal article (peer-reviewed)abstract
- The geochronologic (U-Pb isotopic system of zircons) and isotopic-geochemical (Sm-Nd isotopic system of the bulk rock) studies were performed along the profile extending from the eastern Sarmatia (in the west) to the Middle Volga megablock of Volgo-Uralia (in the east), i.e., across the entire junction zone for dating the integration of Sarmatia and Volgo-Uralia, representing two segments of the East European Craton. It is established that the examined rocks are characterized by the Paleoproterozoic Nd isotopic model age, which varies from 2.1 and 2.4 Ga, except for some samples indicating a similar age of the crust through the entire Sarmatia-Volgo-Uralia junction zone. The highly metamorphosed complexes of the granulite and amphibolite facies constituting the southwestern margin of Volgo-Uralia are Paleoproterozoic, not Archean, in age, contrary to previous views. Two Early Paleoproterozoic lithotectonic complexes are defined in Volgo-Uralia: South Volga metasedimentary and Tersa metasedimentary-volcanogenic. The obtained data confirm the asynchronous integration of individual segments into the East European Craton: the integration of Sarmatia and Volgo-Uralia approximately 2100-2000 Ma ago was followed by the conjunction of this newly-formed continent with Fennoscandia ca. 1800 Ma ago.
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| 3. |
- Bibikova, E. V., et al.
(author)
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The early crust of the Volgo-Uralian segment of the East European Craton: Isotope-geochronological zirconology of metasedimentary rocks of the Bolshecheremshanskaya Formation and their Sm-Nd model ages
- 2015
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In: Stratigraphy and Geological Correlation. - 0869-5938. ; 23:1, s. 1-23
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Journal article (peer-reviewed)abstract
- We present the results of isotope-geochronological study of metasedimentary rocks of the Bolshecheremshanskaya Formation of the Volgo-Uralian segment of the East European Craton carried out to identify their protoliths. 16 samples of high-alumina gneisses from well cores were studied using the Sm-Nd isotope method and T-Nd(DM) model ages. Accessory zircons were selected from rocks with the most ancient model ages (more 3.2 Ga) in three wells: Minnibaevskaya 20000, Novo-Elkhovskaya 20009, and Zai-Karatayskaya 12930 in South Tatarstan. The isotope U-Pb dating of 200 zircon grains was performed on a Cameca 1280 NORDSIM secondary ion mass spectrometer at the Natural History Museum (Stockholm, Sweden). The most applicable sites for analysis of zircon crystals were pre-selected based on cathodoluminescence images. The analytical results demonstrate the diversity of zircon groups in age from 3.8 to 2.6 Ga and together with geochemical features of metasedimentary rocks of the Bolshecheremshanskaya Formation suggest the heterogeneous composition and age of provenance areas under denudation. Occurrence of Eoarchean and Paleoarchean zircons in the clastic material of the protolith of the Bolshecheremshanskaya gneisses indicates the existence of Early Archean crustal terrains in Volgo-Uralia.
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| 4. |
- Jiang, X., et al.
(author)
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Shared heritability and functional enrichment across six solid cancers
- 2019
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10
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Journal article (peer-reviewed)abstract
- Quantifying the genetic correlation between cancers can provide important insights into the mechanisms driving cancer etiology. Using genome-wide association study summary statistics across six cancer types based on a total of 296,215 cases and 301,319 controls of European ancestry, here we estimate the pair-wise genetic correlations between breast, colorectal, head/neck, lung, ovary and prostate cancer, and between cancers and 38 other diseases. We observed statistically significant genetic correlations between lung and head/neck cancer (r(g) = 0.57, p = 4.6 x 10(-8)), breast and ovarian cancer (r(g) = 0.24, p = 7 x 10(-5)), breast and lung cancer (r(g) = 0.18, p = 1.5 x 10(-6)) and breast and colorectal cancer (r(g) = 0.15, p = 1.1 x 10(-4)). We also found that multiple cancers are genetically correlated with non-cancer traits including smoking, psychiatric diseases and metabolic characteristics. Functional enrichment analysis revealed a significant excess contribution of conserved and regulatory regions to cancer heritability. Our comprehensive analysis of cross-cancer heritability suggests that solid tumors arising across tissues share in part a common germline genetic basis.
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| 5. |
- Lebedev, A.A., et al.
(author)
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Amplification of the signal in triode structures of ion detectors based on 6H-SIC epitaxial films
- 2001
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 79:26, s. 4447-4449
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Journal article (peer-reviewed)abstract
- The possibility of about 50 times the inneramplification of signals in SiC-based detectors of short-range ions is shown. The detector has an n-p-n+-like structure, where the p-type base was grown epitaxially on a 6H n+-SiC substrate. To complete the structure a Schottky barrier was made on top. Detector parameters were investigated in a "floating base" regime. Alpha particles from 244Cm were used and the augmentation of signal (E) with increasing applied voltage (U) was investigated. A superlinear increase of E was observed with a significant (tens of times) amplification of the introduced by the alpha particle nonequilibrium charge. It was also found that the nonuniformity of the diffusion-drift carrier transport parameters in the films does not exceed 10%. © 2001 American Institute of Physics.
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| 6. |
- Lebedev, A.A., et al.
(author)
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Highly doped p-type 3C-SiC on 6H-SiC substrates
- 2008
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In: Semiconductor Science and Technology. - : IOP Publishing. - 0268-1242 .- 1361-6641. ; 23:7
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Journal article (peer-reviewed)abstract
- Highly doped p-3C-SiC layers of good crystal perfection have been grown by sublimation epitaxy in vacuum. Analysis of the photoluminescence spectra and temperature dependence of the carrier concentration shows that at least two types of acceptor centers at ∼EV + 0.25 eV and at EV + 0.06-0.07 eV exist in the samples studied. A conclusion is reached that layers of this kind can be used as p-emitters in 3C-SiC devices. © 2008 IOP Publishing Ltd.
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| 7. |
- Lebedev, Alexander, 2000-, et al.
(author)
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A study of thick 3C-SiC epitaxial layers grown on 6H-SiC substrates by sublimation epitaxy in vacuum
- 2007
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In: Semiconductors (Woodbury, N.Y.). - 1063-7826 .- 1090-6479. ; 41:3, s. 263-265
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Journal article (peer-reviewed)abstract
- 3C-SiC epitaxial layers with a thickness of up to 100 μm were grown on 6H-SiC hexagonal substrates by sublimation epitaxy in vacuum. The n-type epitaxial layers with the area in the range 0.3-0.5 cm2 and uncompensated donor concentration N d - N a ∼ (10 17-1018) cm-3 were produced at maximum growth rates of up to 200 μm/h. An X-ray analysis demonstrated that the epitaxial layers are composed of the 3C-SiC polytype, without inclusions of other polytypes. The photoluminescence (PL) spectrum of the layers was found to be dominated by the donor-acceptor (Al-N) recombination band peaked at hv ≈ 2.12 eV. The PL spectrum measured at 6 K was analyzed in detail. It is concluded that the epitaxial layers obtained can serve as substrates for 3C-SiC-based electronic devices. © Nauka/Interperiodica 2007.
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| 8. |
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| 9. |
- Lebedev, S.P., et al.
(author)
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P-type 3C-SiC Grown by Sublimation Epitaxy on 6H-SiC Substrates
- 2009
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In: ECSCRM2008,2008. - Materials Science Forum Vols. 615-617 : Trans Tech Publications. - 9780878493340 ; , s. 177-180
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Conference paper (peer-reviewed)abstract
- Highly doped p-3C-SiC layers of good crystal perfection have been grown by sublimation epitaxy in vacuum. Analysis of the photoluminescence (PL) spectra and temperature dependence of the carrier concentration shows that at least two types of acceptor centers at ~EV + 0.25 eV and at EV + 0.06-0.07 eV exist in the samples studied. A conclusion is made that layers of this kind can be used as p-emitters in 3C-SiC devices.
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