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| 2. |
- Grigorenko, L, et al.
(author)
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Scientific program of DERICA-prospective accelerator and storage ring facility for radioactive ion beam research
- 2019
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In: Physics-Uspekhi. - 1468-4780 .- 1063-7869. ; 62:7, s. 675-690
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Journal article (peer-reviewed)abstract
- Studies of radioactive ions (RIs) are the most thriving field of low-energy nuclear physics. In this paper, the concept and the scientific agenda of the prospective accelerator and storage ring facility for RI beam (RIB) research are proposed for a large-scale international project based at the Flerov Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research. The motivation for the new facility is discussed and its characteristics are briefly presented and shown to be comparable to those of advanced world centers, the so-called "RIB factories". In the project, the emphasis is made on studies with short-lived RIBs in storage rings. A unique feature of the project is the possibility of studying electron-RI interactions in a collider experiment to determine the fundamental properties of nuclear matter, in particular, electromagnetic form factors of exotic nuclei.
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| 3. |
- Damgaard, P. D., et al.
(author)
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137 ancient human genomes from across the Eurasian steppes
- 2018
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 557:7705, s. 369-374
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Journal article (peer-reviewed)abstract
- For thousands of years the Eurasian steppes have been a centre of human migrations and cultural change. Here we sequence the genomes of 137 ancient humans (about 1x average coverage), covering a period of 4,000 years, to understand the population history of the Eurasian steppes after the Bronze Age migrations. We find that the genetics of the Scythian groups that dominated the Eurasian steppes throughout the Iron Age were highly structured, with diverse origins comprising Late Bronze Age herders, European farmers and southern Siberian hunter-gatherers. Later, Scythians admixed with the eastern steppe nomads who formed the Xiongnu confederations, and moved westward in about the second or third century bc, forming the Hun traditions in the fourthfifth century ad, and carrying with them plague that was basal to the Justinian plague. These nomads were further admixed with East Asian groups during several short-term khanates in the Medieval period. These historical events transformed the Eurasian steppes from being inhabited by Indo-European speakers of largely West Eurasian ancestry to the mostly Turkic-speaking groups of the present day, who are primarily of East Asian ancestry.
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| 4. |
- Litnovsky, A., et al.
(author)
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Diagnostic mirrors for ITER : research in the frame of International Tokamak Physics Activity
- 2019
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In: Nuclear Fusion. - : IOP PUBLISHING LTD. - 0029-5515 .- 1741-4326. ; 59:6
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Journal article (peer-reviewed)abstract
- Mirrors will be used as first plasma-viewing elements in optical and laser-based diagnostics in ITER. Deterioration of the mirror performance due to e.g. sputtering of the mirror surface by plasma particles or deposition of impurities will hamper the entire performance of the affected diagnostic and thus affect ITER operation. The Specialists Working Group on First Mirrors (FM SWG) in the Topical Group on Diagnostics of the International Tokamak Physics Activity (ITPA) plays an important role in finding solutions for diagnostic first mirrors. Sound progress in research and development of diagnostic mirrors in ITER was achieved since the last overview in 2009. Single crystal (SC) rhodium (Rh) mirrors became available. SC rhodium and molybdenum (Mo) mirrors survived in conditions corresponding to similar to 200 cleaning cycles with a negligible degradation of reflectivity. These results are important for a mirror cleaning system which is presently under development. The cleaning system is based on sputtering of contaminants by plasma. Repetitive cleaning was tested on several mirror materials. Experiments comprised contamination/cleaning cycles. The reflectivity SC Mo and Rh mirrors has changed insignificantly after 80 cycles. First in situ cleaning using radiofrequency (RF) plasma was conducted in EAST tokamak with a mock-up plate of ITER edge Thomson Scattering (ETS) with five inserted mirrors. Contaminants from the mirrors were removed. Physics of cleaning discharge was studied both experimentally and by modeling. Mirror contamination can also be mitigated by protecting diagnostic ducts. A deposition mitigation (DeMi) duct system was exposed in KSTAR. The real-time measurement of deposition in the diagnostic duct was pioneered during this experiment. Results evidenced the dominating effect of the wall conditioning and baking on contamination inside the duct. A baffled cassette with mirrors was exposed at the main wall of JET for 23,6 plasma hours. No significant degradation of reflectivity was measured on mirrors located in the ducts. Predictive modeling was further advanced. A model for the particle transport, deposition and erosion at the port-plug was used in selecting an optical layout of several ITER diagnostics. These achievements contributed to the focusing of the first mirror research thus accelerating the diagnostic development. Modeling requires more efforts. Remaining crucial issues will be in a focus of the future work of the FM SWG.
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| 5. |
- Maccaferri, N., et al.
(author)
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Tuning the Magneto-Optical Response of Nanosize Ferromagnetic Ni Disks Using the Phase of Localized Plasmons
- 2013
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 111:16
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Journal article (peer-reviewed)abstract
- We explore the influence of the phase of localized plasmon resonances on the magneto-optical activity of nanoferromagnets. We demonstrate that these systems can be described as two orthogonal damped oscillators coupled by the spin-orbit interaction. We prove that only the spin-orbit induced transverse plasmon plays an active role on the magneto-optical properties by controlling the relative amplitude and phase lag between the two oscillators. Our theoretical predictions are fully confirmed by magneto-optical Kerr effect and optical extinction measurements in nanostructures of different size and shape.
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| 6. |
- Zaman, Quaid, et al.
(author)
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Water Diffusion Effectsat Gold-Graphene Interfaces Supporting Surface Plasmon Polaritons
- 2022
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In: The Journal of Physical Chemistry C. - : AMER CHEMICAL SOC. - 1932-7447 .- 1932-7455. ; 126:32, s. 13905-13919
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Journal article (peer-reviewed)abstract
- We present a detailed investigation on the effects of water diffusion at the different interfaces of gold-graphene plasmonic sensors on the propagation of the supported surface plasmon polaritons (SPPs). The substrate/metal interfacial chemical reactions are investigated by monitoring the full width at half-maximum of the SPR reflectivity curve. Although protection by single-layer graphene (SLG) grown by chemical vapor deposition inhibits the chemical reactions happening at the metal-dielectric interfaces, SPR experimental results confirm that water diffusion paths through the borders of graphene domains are still present into the plasmonic sensors. Density functional theory calculations show that the doping level of SLG after the transfer on gold as well as interfacial charge transfer can be tuned in the presence of water molecules. On these bases, we propose a simplified effective medium approach for heterogeneous metal-carbon interfaces, where the interaction between the surface atomic layers of the gold thin film, water molecules, and the SLG induces the creation of an extended charge density difference region crossing the Au/H2O/SLG/H2O heterointerface. The latter is modeled as an ultrathin effective medium with a thickness and extraordinary optical susceptivity and conductivity that are different from those of the free-standing graphene. In this context, the extraordinary refractive index and thickness of the graphene-gold effective medium are measured in the near-infrared on the low-damping SPR platforms by applying the two-medium SPR method. The results are coherent with graphene n-doping in water environment, showing that the optically excited electrons along the extraordinary axis have a substantial bonding character and that the enhancement of the sensitivity of the gold-graphene plasmonic sensors is not related to a shift in the plasma frequency of the metal layer but to the changes in the extraordinary polarizability of graphene. The research highlights the importance of the SLG-substrate and SLG-environment interactions in graphene-protected plasmonics and optoelectronics.
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| 7. |
- Benedict, S., et al.
(author)
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Colloidal lithography nanostructured Pd/PdOx core-shell sensor for ppb level H2S
- 2018
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In: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 29:25
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Journal article (peer-reviewed)abstract
- In this work we report on plasma oxidation of palladium (Pd) to form reliable palladium/palladium oxide (Pd/PdOx) core-shell sensor for ppb level H2S detection and its performance improvement through nanostructuring using hole-mask colloidal lithography (HCL). The plasma oxidation parameters and the sensor operating conditions are optimized to arrive at a sensor device with high sensitivity and repeatable response for H2S. The plasma oxidized palladium/palladium oxide sensor shows a response of 43.1% at 3 ppm H2S at the optimum operating temperature of 200 degrees C with response and recovery times of 24 s and 155 s, respectively. The limit of detection (LoD) of the plasma oxidised beam is 10 ppb. We further integrate HCL, a bottom-up and cost-effective process, to create nanodiscs of fixed diameter of 100 nm and varying heights (10, 15 and 20 nm) on 10 nm thin Pd beam which is subsequently plasma oxidized to improve the H2S sensing characteristics. The nanostructured Pd/PdOx sensor with nanodiscs of 100 nm diameter and 10 nm height shows an enhancement in sensing performance by 11.8% at same operating temperature and gas concentration. This nanostructured sensor also shows faster response and recovery times (15s and 100s, respectively) compared to the unstructured Pd/PdOx counterpart together with an experimental LoD of 10 ppb and the estimated limit going all the way down to 2 ppb. Material characterization of the fabricated Pd/PdOx sensors is done using UV-vis spectroscopy and x-ray photoemission spectroscopy.
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| 8. |
- 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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