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Träfflista för sökning "WFRF:(Volkov Denis) "

Sökning: WFRF:(Volkov Denis)

  • Resultat 1-7 av 7
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1.
  • Bourlev, Vladimir, et al. (författare)
  • Different proliferative and apoptotic activity in peripheral versus central parts of human uterine leiomyomas
  • 2003
  • Ingår i: Gynecologic and Obstetric Investigation. - : S. Karger AG. - 0378-7346 .- 1423-002X. ; 55:4, s. 199-204
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVE:To determine whether there are differences in proliferative and apoptotic activity and in expression of sex steroid receptors between central and peripheral parts of human uterine leiomyomas in different menstrual cycle phases.METHODS:Biopsy specimens of the myometrium and peripheral and central parts of uterine leiomyomas were obtained from 15 women in the proliferative phase and 8 women in the secretory phase. Mitotic cells were detected by immunohistochemical staining for Ki67. Apoptotic cells were detected by the TUNEL method. Mitotic and apoptotic indexes were calculated. Tissue levels of oestrogen and progesterone receptors were measured using a commercial monoclonal receptor enzyme immunoassay kit.RESULTS:During the secretory phase the mitotic index was significantly higher in the peripheral than in the central parts of the leiomyomas. During the proliferative phase the apoptotic index was significantly higher in the peripheral compared with the central parts. These differences were not reflected by differences in receptor expression.CONCLUSIONS:The results of this study suggest that the growth of a human uterine leiomyoma mainly occurs in the peripheral parts of the tumour, during the secretory phase of the menstrual cycle. The findings emphasise the importance of being consistent when taking samples for research work.
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2.
  • Ermolaev, Georgy A., et al. (författare)
  • Broadband optical properties of monolayer and bulk MoS 2
  • 2020
  • Ingår i: npj 2D Materials and Applications. - : Springer Science and Business Media LLC. - 2397-7132. ; 4:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Layered semiconductors such as transition metal dichalcogenides (TMDs) offer endless possibilities for designing modern photonic and optoelectronic components. However, their optical engineering is still a challenging task owing to multiple obstacles, including the absence of a rapid, contactless, and the reliable method to obtain their dielectric function as well as to evaluate in situ the changes in optical constants and exciton binding energies. Here, we present an advanced approach based on ellipsometry measurements for retrieval of dielectric functions and the excitonic properties of both monolayer and bulk TMDs. Using this method, we conduct a detailed study of monolayer MoS2 and its bulk crystal in the broad spectral range (290–3300 nm). In the near- and mid-infrared ranges, both configurations appear to have no optical absorption and possess an extremely high dielectric permittivity making them favorable for lossless subwavelength photonics. In addition, the proposed approach opens a possibility to observe a previously unreported peak in the dielectric function of monolayer MoS2 induced by the use of perylene-3,4,9,10-tetracarboxylic acid tetrapotassium salt (PTAS) seeding promoters for MoS2 synthesis and thus enables its applications in chemical and biological sensing. Therefore, this technique as a whole offers a state-of-the-art metrological tool for next-generation TMD-based devices.
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3.
  • Ermolaev, G. A., et al. (författare)
  • Giant optical anisotropy in transition metal dichalcogenides for next-generation photonics
  • 2021
  • Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723 .- 2041-1723. ; 12:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Large optical anisotropy observed in a broad spectral range is of paramount importance for efficient light manipulation in countless devices. Although a giant anisotropy has been recently observed in the mid-infrared wavelength range, for visible and near-infrared spectral intervals, the problem remains acute with the highest reported birefringence values of 0.8 in BaTiS3 and h-BN crystals. This issue inspired an intensive search for giant optical anisotropy among natural and artificial materials. Here, we demonstrate that layered transition metal dichalcogenides (TMDCs) provide an answer to this quest owing to their fundamental differences between intralayer strong covalent bonding and weak interlayer van der Waals interaction. To do this, we made correlative far- and near-field characterizations validated by first-principle calculations that reveal a huge birefringence of 1.5 in the infrared and 3 in the visible light for MoS2. Our findings demonstrate that this remarkable anisotropy allows for tackling the diffraction limit enabling an avenue for on-chip next-generation photonics. Optical anisotropy in a broad spectral range is pivotal to efficient light manipulation. Here, the authors measure a birefringence of 1.5 in the infrared range and 3 in the visible light for MoS2.
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4.
  • Kılınç, Gülşah Merve, et al. (författare)
  • Human population dynamics and Yersinia pestis in ancient northeast Asia
  • 2021
  • Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 7:2
  • Tidskriftsartikel (refereegranskat)abstract
    • We present genome-wide data from 40 individuals dating to c.16,900 to 550 years ago in northeast Asia. We describe hitherto unknown gene flow and admixture events in the region, revealing a complex population history. While populations east of Lake Baikal remained relatively stable from the Mesolithic to the Bronze Age, those from Yakutia and west of Lake Baikal witnessed major population transformations, from the Late Upper Paleolithic to the Neolithic, and during the Bronze Age, respectively. We further locate the Asian ancestors of Paleo-Inuits, using direct genetic evidence. Last, we report the most northeastern ancient occurrence of the plague-related bacterium, Yersinia pestis. Our findings indicate the highly connected and dynamic nature of northeast Asia populations throughout the Holocene.
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5.
  • Kılınç, Gülşah Merve, et al. (författare)
  • Investigating Holocene human population history in North Asia using ancient mitogenomes
  • 2018
  • Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 8
  • Tidskriftsartikel (refereegranskat)abstract
    • Archaeogenomic studies have largely elucidated human population history in West Eurasia during the Stone Age. However, despite being a broad geographical region of significant cultural and linguistic diversity, little is known about the population history in North Asia. We present complete mitochondrial genome sequences together with stable isotope data for 41 serially sampled ancient individuals from North Asia, dated between c. 13,790 BP and c. 1,380 BP extending from the Palaeolithic to the Iron Age. Analyses of mitochondrial DNA sequences and haplogroup data of these individuals revealed the highest genetic affinity to present-day North Asian populations of the same geographical region suggesting a possible long-term maternal genetic continuity in the region. We observed a decrease in genetic diversity over time and a reduction of maternal effective population size (Ne) approximately seven thousand years before present. Coalescent simulations were consistent with genetic continuity between present day individuals and individuals dating to 7,000 BP, 4,800 BP or 3,000 BP. Meanwhile, genetic differences observed between 7,000 BP and 3,000 BP as well as between 4,800 BP and 3,000 BP were inconsistent with genetic drift alone, suggesting gene flow into the region from distant gene pools or structure within the population. These results indicate that despite some level of continuity between ancient groups and present-day populations, the region exhibits a complex demographic history during the Holocene.
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6.
  • Kostin, Alexander I., et al. (författare)
  • Impact of pathogen reduction methods on immunological properties of the COVID-19 convalescent plasma
  • 2021
  • Ingår i: Vox Sanguinis. - : Wiley. - 0042-9007 .- 1423-0410. ; 116:6, s. 665-672
  • Tidskriftsartikel (refereegranskat)abstract
    • Background and objectives: COVID-19 convalescent plasma is an experimental treatment against SARS-CoV-2. The aim of this study is to assess the impact of different pathogen reduction methods on the levels and virus neutralizing activity of the specific antibodies against SARS-CoV2 in convalescent plasma. Materials and methods: A total of 140 plasma doses collected by plasmapheresis from COVID-19 convalescent donors were subjected to pathogen reduction by three methods: methylene blue (M)/visible light, riboflavin (R)/UVB and amotosalen (A)/UVA. To conduct a paired comparison, individual plasma doses were divided into 2 samples that were subjected to one of these methods. The titres of SARS-CoV2 neutralizing antibodies (NtAbs) and levels of specific immunoglobulins to RBD, S- and N-proteins of SARS-CoV-2 were measured before and after pathogen reduction. Results: The methods reduced NtAbs titres differently: among units with the initial titre 80 or above, 81% of units remained unchanged and 19% decreased by one step after methylene blue; 60% were unchanged and 40% decreased by one step after amotosalen; after riboflavin 43% were unchanged and 50% (7%, respectively) had a one-step (two-step, respectively) decrease. Paired two-sample comparisons (M vs. A, M vs. R and A vs. R) revealed that the largest statistically significant decrease in quantity and activity of the specific antibodies resulted from the riboflavin treatment. Conclusion: Pathogen reduction with methylene blue or with amotosalen provides the greater likelihood of preserving the immunological properties of the COVID-19 convalescent plasma compared to riboflavin.
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7.
  • Lee, Craig M., et al. (författare)
  • A Framework for the Development, Design and Implementation of a Sustained Arctic Ocean Observing System
  • 2019
  • Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 6
  • Forskningsöversikt (refereegranskat)abstract
    • Rapid Arctic warming drives profound change in the marine environment that have significant socio-economic impacts within the Arctic and beyond, including climate and weather hazards, food security, transportation, infrastructure planning and resource extraction. These concerns drive efforts to understand and predict Arctic environmental change and motivate development of an Arctic Region Component of the Global Ocean Observing System (ARCGOOS) capable of collecting the broad, sustained observations needed to support these endeavors. This paper provides a roadmap for establishing the ARCGOOS. ARCGOOS development must be underpinned by a broadly endorsed framework grounded in high-level policy drivers and the scientific and operational objectives that stem from them. This should be guided by a transparent, internationally accepted governance structure with recognized authority and organizational relationships with the national agencies that ultimately execute network plans. A governance model for ARCGOOS must guide selection of objectives, assess performance and fitness-to-purpose, and advocate for resources. A requirements-based framework for an ARCGOOS begins with the Societal Benefit Areas (SBAs) that underpin the system. SBAs motivate investments and define the system's science and operational objectives. Objectives can then be used to identify key observables and their scope. The domains of planning/policy, strategy, and tactics define scope ranging from decades and basins to focused observing with near real time data delivery. Patterns emerge when this analysis is integrated across an appropriate set of SBAs and science/operational objectives, identifying impactful variables and the scope of the measurements. When weighted for technological readiness and logistical feasibility, this can be used to select Essential ARCGOOS Variables, analogous to Essential Ocean Variables of the Global Ocean Observing System. The Arctic presents distinct needs and challenges, demanding novel observing strategies. Cost, traceability and ability to integrate region-specific knowledge have to be balanced, in an approach that builds on existing and new observing infrastructure. ARCGOOS should benefit from established data infrastructures following the Findable, Accessible, Interoperable, Reuseable Principles to ensure preservation and sharing of data and derived products. Linking to the Sustaining Arctic Observing Networks (SAON) process and involving Arctic stakeholders, for example through liaison with the International Arctic Science Committee (IASC), can help ensure success.
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