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| 2. |
- Dmitriev, Alexey A, et al.
(author)
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Genetic and epigenetic analysis of non-small cell lung cancer with NotI-microarrays
- 2012
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In: Epigenetics. - : Landes Bioscience. - 1559-2294 .- 1559-2308. ; 7:5, s. 502-513
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Journal article (peer-reviewed)abstract
- This study aimed to clarify genetic and epigenetic alterations that occur during lung carcinogenesis and to design perspective sets of newly identified biomarkers. The original method includes chromosome 3 specific NotI-microarrays containing 180 NotI clones associated with genes for hybridization with 40 paired normal/tumor DNA samples of primary lung tumors: 28 squamous cell carcinomas (SCC) and 12 adenocarcinomas (ADC). The NotI-microarray data were confirmed by qPCR and bisulfite sequencing analyses. Forty-four genes showed methylation and/or deletions in more than 15% of non-small cell lung cancer (NSCLC) samples. In general, SCC samples were more frequently methylated/deleted than ADC. Moreover, the SCC alterations were observed already at stage I of tumor development, whereas in ADC many genes showed tumor progression specific methylation/deletions. Among genes frequently methylated/deleted in NSCLC, only a few were already known tumor suppressor genes: RBSP3 (CTDSPL), VHL and THRB. The RPL32, LOC285205, FGD5 and other genes were previously not shown to be involved in lung carcinogenesis. Ten methylated genes, i.e., IQSEC1, RBSP3, ITGA9, FOXP1, LRRN1, GNAI2, VHL, FGD5, ALDH1L1 and BCL6 were tested for expression by qPCR and were found downregulated in the majority of cases. Three genes (RBSP3, FBLN2 and ITGA9) demonstrated strong cell growth inhibition activity. A comprehensive statistical analysis suggested the set of 19 gene markers, ANKRD28, BHLHE40, CGGBP1, RBSP3, EPHB1, FGD5, FOXP1, GORASP1/TTC21, IQSEC1, ITGA9, LOC285375, LRRC3B, LRRN1, MITF, NKIRAS1/RPL15, TRH, UBE2E2, VHL, WNT7A, to allow early detection, tumor progression, metastases and to discriminate between SCC and ADC with sensitivity and specificity of 80-100%.
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| 3. |
- Boris, Andrey A., et al.
(author)
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Evidence for Nonlocal Electrodynamics in Planar Josephson Junctions
- 2013
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 111:11
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Journal article (peer-reviewed)abstract
- We study the temperature dependence of the critical current modulation I-c(H) for two types of planar Josephson junctions: a low-T-c Nb/CuNi/Nb and a high-T-c YBa2Cu3O7-delta bicrystal grain-boundary junction. At low T both junctions exhibit a conventional behavior, described by the local sine-Gordon equation. However, at elevated T the behavior becomes qualitatively different: the I-c(H) modulation field Delta H becomes almost T independent and neither Delta H nor the critical field for the penetration of Josephson vortices vanish at T-c. Such an unusual behavior is in good agreement with theoretical predictions for junctions with nonlocal electrodynamics. We extract absolute values of the London penetration depth lambda from our data and show that a crossover from local to nonlocal electrodynamics occurs with increasing T when lambda(T) becomes larger than the electrode thickness.
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| 4. |
- Kashuba, Vladimir, et al.
(author)
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NotI Microarrays: Novel Epigenetic Markers for Early Detection and Prognosis of High Grade Serous Ovarian Cancer
- 2012
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In: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 13:10, s. 13352-13377
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Journal article (peer-reviewed)abstract
- Chromosome 3-specific NotI microarray (NMA) containing 180 clones with 188 genes was used in the study to analyze 18 high grade serous ovarian cancer (HGSOC) samples and 7 benign ovarian tumors. We aimed to find novel methylation-dependent biomarkers for early detection and prognosis of HGSOC. Thirty five NotI markers showed frequency of methylation/deletion more or equal to 17%. To check the results of NMA hybridizations several samples for four genes (LRRC3B, THRB, ITGA9 and RBSP3 (CTDSPL)) were bisulfite sequenced and confirmed the results of NMA hybridization. A set of eight biomarkers: NKIRAS1/RPL15, THRB, RBPS3 (CTDSPL), IQSEC1, NBEAL2, ZIC4, LOC285205 and FOXP1, was identified as the most prominent set capable to detect both early and late stages of ovarian cancer. Sensitivity of this set is equal to (72 +/- 11)% and specificity (94 +/- 5)%. Early stages represented the most complicated cases for detection. To distinguish between Stages I + II and Stages III + IV of ovarian cancer the most perspective set of biomarkers would include LOC285205, CGGBP1, EPHB1 and NKIRAS1/RPL15. The sensitivity of the set is equal to (80 +/- 13)% and the specificity is (88 +/- 12)%. Using this technique we plan to validate this panel with new epithelial ovarian cancer samples and add markers from other chromosomes.
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| 6. |
- Golod, Taras, et al.
(author)
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High bias anomaly in YBa2Cu3O7-x/LaMnO3+delta/YBa2Cu3O7-x superconductor/ferromagnetic insulator/superconductor junctions : Evidence for a long-range superconducting proximity effect through the conduction band of a ferromagnetic insulator
- 2013
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In: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 87:13, s. 134520-
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Journal article (peer-reviewed)abstract
- We study the perpendicular transport characteristics of small superconductor/ferromagnetic insulator/superconductor (YBa2Cu3O7-x/LaMnO3+delta/YBa2Cu3O7-x) tunnel junctions. At a large bias voltage V similar to 1 V we observe a steplike onset of excess current that occurs below the superconducting transition temperature T < T-c and is easily suppressed by a magnetic field. The phenomenon is attributed to a different type of the superconducting proximity effect of nonequilibrium electrons injected into the conduction band of the ferromagnetic insulator via a Fowler-Nordheim tunneling process. The occurrence of a strongly nonequilibrium population is confirmed by the detection of photon emission at large bias voltage. Since the conduction band in our ferromagnetic insulator is strongly spin polarized, the long range (20 nm) of the observed proximity effect provides evidence for an unconventional spin-triplet superconducting state.
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| 7. |
- Jacobs, Thorsten, et al.
(author)
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Electron-tunneling measurements of low-T-c single-layer Bi2+xSr2-yCuO6+delta : Evidence for a scaling disparity between superconducting and pseudogap states
- 2012
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In: Physical Review B. - 2469-9950. ; 86:21
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Journal article (peer-reviewed)abstract
- We experimentally study intrinsic tunneling and high magnetic field (up to 65 T) transport characteristics of the single-layer cuprate Bi2+xSr2-yCuO6+delta, with a very low superconducting critical temperature T-c less than or similar to 4 K. It is observed that the superconducting gap, the collective bosonic mode energy, the upper critical field, and the fluctuation temperature range are scaling down with T-c, while the corresponding pseudogap characteristics remain the same as in high-T-c cuprates with 20 to 30 times higher T-c. The observed disparity of the superconducting and pseudogap scales clearly reveals their different origins.
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| 8. |
- Katterwe, Sven Olof, et al.
(author)
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Low anisotropy of the upper critical field in a strongly anisotropic layered cuprate Bi2.15Sr1.9CuO6+δ : Evidence for a paramagnetically limited superconductivity
- 2014
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In: Physical Review B. - 2469-9950 .- 2469-9969. ; 89:21
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Journal article (peer-reviewed)abstract
- We study angular-dependent magnetoresistance in a low-T-c layered cuprate Bi2.15Sr1.9CuO6+delta. The low Tc similar to 4 K allows complete suppression of superconductivity by modest magnetic fields and facilitates accurate analysis of the upper critical field H-c2. We observe a universal exponential decay of fluctuation conductivity in a broad range of temperatures above Tc and propose a method for extraction of H-c2(T) from the scaling analysis of the fluctuation conductivity at T > T c. Our main result is observation of a surprisingly low H-c2 anisotropy similar to 2, which is much smaller than the effective mass anisotropy of the material similar to 300. We show that the anisotropy is decreasing with increasing field and saturates at a small value when the field reaches the paramagnetic limit. We argue that the dramatic discrepancy of high-field and low-field anisotropies is clear evidence for paramagnetically limited superconductivity.
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| 9. |
- Katterwe, Sven-Olof, et al.
(author)
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Superluminal geometrical resonances observed in Bi2Sr2CaCu2O8+x intrinsic Josephson junctions
- 2010
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In: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 82:2
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Journal article (peer-reviewed)abstract
- We study Fiske steps in small Bi2Sr2CaCu2O8+x mesa structures, containing only a few stacked intrinsic Josephson junctions. Careful alignment of magnetic field prevents penetration of Abrikosov vortices and facilitates observation of a large variety of high-quality geometrical resonances, including superluminal with velocities larger than the slowest velocity of electromagnetic waves. A small number of junctions limits the number of resonant modes and allows accurate identification of modes and velocities. It is shown that superluminal geometrical resonances can be excited by subluminal fluxon motion and that flux flow itself becomes superluminal at high magnetic fields. We argue that observation of high-quality superluminal geometrical resonances is crucial for realization of the coherent flux-flow oscillator in the terahertz frequency range.
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| 10. |
- Krasnov, Vladimir M., et al.
(author)
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Comparative analysis of tunneling magnetoresistance in low-Tc Nb/Al-AlOx/Nb and high-Tc Bi2−yPbySr2CaCu2O8+δ intrinsic Josephson junctions
- 2011
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In: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 84:5
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Journal article (peer-reviewed)abstract
- We perform a detailed comparison of magnetotunneling in conventional low-Tc Nb/Al-AlOx/Nb junctions with that in slightly overdoped Bi2−yPbySr2CaCu2O8+δ [Bi(Pb)-2212] intrinsic Josephson junctions and with microscopic calculations. It is found that both types of junctions behave in a qualitatively similar way. Both magnetic field and temperature suppress superconductivity in the state-conserving manner. This leads to the characteristic sign change of tunneling magnetoresistance from the negative at the subgap to the positive at the sum-gap bias. We derived theoretically and verified experimentally scaling laws of magnetotunneling characteristics and employ them for accurate extraction of the upper critical field Hc2. For Nb an extended region of surface superconductivity at Hc2c3 is observed. The parameters of Bi(Pb)-2212 were obtained from self-consistent analysis of magnetotunneling data at different levels of bias, dissipation powers, and for different mesa sizes, which precludes the influence of self-heating. It is found that Hc2(0) for Bi(Pb)-2212 is ≃T→Tc T and decreases significantly at T→Tc. The amplitude of subgap magnetoresistance is suppressed exponentially at T>Tc/2, but remains negative, although very small, above Tc. This may indicate the existence of an extended fluctuation region, which, however, does not destroy the general second-order type of the phase transition at Tc.
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