58 research outputs found
Characteristic length for pinning force density in
The pinning force density (where is the
critical current density, is applied magnetic field) is one of main
quantities which characterizes the resilience of a superconductor to carry
dissipative-free transport current in applied magnetic field. Kramer (1973 J.
Appl. Phys. 44 1360) and Dew-Hughes (1974 Phil. Mag. 30 293) proposed a widely
used scaling law for the pinning force density amplitude:
,
where , , , and are free-fitting parameters.
Since late 1970-s till now, several research groups reported experimental data
for the dependence of on the average grain size, , in
-based conductors. Godeke (2006 Supercond. Sci. Techn. 19 R68)
proposed that the dependence obeys the law . However, this scaling law has several problems, for instance, the
logarithm is taken from a non-dimensionless variable, and for large grain sizes and for . Here we reanalysed full inventory of publicly available
data for conductors and found that the dependence
can be described by law, where the
characteristic length, , is varying within a remarkably narrow range,
i.e. , for samples fabricated by different
technologies. The interpretation of the result is based on an idea that the
in-field supercurrent is flowing within a thin surface layer (the thickness of
) near the grain boundary surfaces. Alternative interpretation is
that represents characteristic length for the exponentially decay
flux pinning potential from dominant defects in superconductors,
which are grain boundaries.Comment: 22 pages, 8 figure
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Optimized 3D Segmentation Algorithm for Shelly Sand Images
There is much to be gained from analysing and studying calcareous sediment, with applications ranging from the study of climate change, rock dating, and even building offshore oil rigs and wind farms. One way of performing this analysis is to obtain a µCT scan of the sediment, allowing scientists and engineers to automate much of their analysis using software. Many existing and prospective analysis techniques require handling individual grains. Thus, fast and effective segmentation is an essential first step for any such analysis. Segmentation is non-trivial; these scans hold a lot of information, exhibit ambiguous boundaries between objects, and many objects are hollow, making it even more difficult to apply traditional watershed segmentation. Addressing these issues, in this paper we propose an optimized 3D segmentation (O3DS) algorithm based on watersheds. We make use of branch recursion, partition the image by height prior to segmentation, artificially reducing the size of the largest connected objects. These and additional changes are extremely effective in optimizing performance; O3DS reduces the time to segment a 659x925x932 scan of sediment by 95.4% and produces better or comparable results when compared to similar implementation by our co-author
Traditional and Modern Protective Media for the Low-Temperature Bacteria Preservation
Presented are the literature data on the efficiency of bacteria preservation at temperatures ranging from -20 to -196 °C in the protective media containing such cryoprotectors as glycerol, dimethyl sulfoxide, carbo-hydrates, substances of protein origin specified by regulatory guidelines. Most of the focus is on the publications reporting the results of the long-term bacteria preservation at sub-zero temperatures, optimization of the protective media for pathogenic bacteria, and usage of the compounds with potential cryoprotective activity. Noted is the necessity for approbation of the specified protective media for the conserved bacteria species at the applied preserving temperatures. One of the approaches to the enhancement of the low-temperature preservation techniques is a search for natural protectors, which can provide for surviving of bacteria in the unfavorable conditions, including low temperatures, and a search for possibility to integrate these natural protectors into the cryoprotective media. Displayed are the results of effective application of glycerol-betaine, and polysaccharides of Arctic microorganisms for the low-temperature bacteria preservation
Polynuclear Metallic Architectures Based on Fluorinated Functionalized Diketonates
K.Y.S. is thankful to the Council for grants of the President of Russian Federation (grant no. 1453.2019.3)
Dihydroazolopyrimidine crownophanes. Synthesis and tuberculostatic activity
Azolo[1,5-a]pyrimidines are considered to be purine analogues and they form one of the most promising groups of biologically active compounds[1-16] in medicinal chemistry. One of the strategies enhancing biochemical activity of azolo[1,5-a]pyrimidines is introduction of functional groups responsible for solubility and transport into their pharmacophore nucleus.[1,16] In this study, we wish to report ultrasound- and microwave-assisted one-pot cascade synthesis of macroheterocyclic 1-phenyl-2-(21-phenyl-10,11,13,14,20,20a-hexahydro-4aH-dibenzo-[13,14: 8,9][1,4,7] trioxacyclotetradecino[11,10-e]azolo[1,5-a]pyrimidin-20-yl)-1-ethanones. US and MV irradiation of the reaction mixtures under alkaline catalysis was found to promote a significant reduction of the reaction times (from 35 to 2 hours) and shift of the equilibrium in favor of 6,7-dihydroazolo[1,5-a]pyrimidine crownophanes in excellent yields (from 18[24] to 75 %). The high regio and stereoselectivity of the (R,S,R)-macroheterocyclic diastereomer formation was established by means of X-ray crystallography, 1H NMR spectroscopy, as well as HPLC and preparative chromatography. The aq. DMF appeared to be an acceptable solvent for stabilization of the important template-assisted pseudo-cyclic complex of the chalcone podand in this synthesis. Introduction of the dibenzo-crown ether transport moiety into 6,7-dihydroazolo[1,5-a]pyrimidines proved to increase their tuberculostatic activity in order to MIC 3.15 mg/ml. © ISUCT Publishing
Comparison of 2D Optical Imaging and 3D Microtomography Shape Measurements of a Coastal Bioclastic Calcareous Sand
This article compares measurements of particle shape parameters from three-dimensional (3D) X-ray micro-computed tomography (μCT) and two-dimensional (2D) dynamic image analysis (DIA) from the optical microscopy of a coastal bioclastic calcareous sand from Western Australia. This biogenic sand from a high energy environment consists largely of the shells and tests of marine organisms and their clasts. A significant difference was observed between the two imaging techniques for measurements of aspect ratio, convexity, and sphericity. Measured values of aspect ratio, sphericity, and convexity are larger in 2D than in 3D. Correlation analysis indicates that sphericity is correlated with convexity in both 2D and 3D. These results are attributed to inherent limitations of DIA when applied to platy sand grains and to the shape being, in part, dependent on the biology of the grain rather than a purely random clastic process, like typical siliceous sands. The statistical data has also been fitted to Johnson Bounded Distribution for the ease of future use. Overall, this research demonstrates the need for high-quality 3D microscopy when conducting a micromechanical analysis of biogenic calcareous sand
A Rare Example of Discrete Lanthanide–Lithium Tetrakis-β-Diketonates: Synthesis, Structures, and Luminescence Properties
Abstract: The reactions of functionalized lithium CF3-β-diketonate (LiL) with europium(III) and terbium(III) chlorides in acetonitrile afford heterobimetallic complexes with the general formula [LiL-nL4(H2O)](CH3CN) (Ln = Eu (IIIa) and Tb (IIIb)). It is found that Ln–Li tetrakis-β-diketonates can also be prepared by the crystallization from acetonitrile of the previously synthesized complexes [(LnL3)(LiL)(MeOH)] (I) and [(LnL3)(LiL)(H2O)] (II). For the first time, the single crystals of the compounds in a series of Ln–Li tetrakis-β-diketonates are characterized by X-ray diffraction analysis (CIF files CCDC nos. 1973632 (IIIa) and 1973633 (IIIb)). The photoluminescence properties of the synthesized heterometallic complexes in the solid state are studied. © 2020, Pleiades Publishing, Ltd.This work was supported by the Russian Foundation for Basic Research (project no. 18-33-20124), Council for Grants of President of the Russian Federation (grant no. MK-1453.2019.3), and basic themes of the Russian Academy of Sciences (state registration nos. AAAA-A19-119011790132-7 and AAAA-A19-119012490006-1)
Assessment of the cardiovascular system characteristics for preschool children (5-6 years old) following dif-ferent physical education programs
В статье проанализированы следующие показатели: процент изменения пульса и пульсового давления после физической нагрузки, показатель качества реакции (ПКР) на физическую нагрузку детей дошкольного возраста, занимающихся по разным программам физического воспитанияThe following characteristics are analyzed in the article: the pulse percentage change and pulse pressure after exercise load, reaction quality factor (RQF) on exercise load for preschool children following different physical education program
Breast cancer risk genes: association analysis in more than 113,000 women
BACKGROUNDGenetic testing for breast cancer susceptibility is widely used, but for many genes, evidence of an association with breast cancer is weak, underlying risk estimates are imprecise, and reliable subtype-specific risk estimates are lacking.METHODSWe used a panel of 34 putative susceptibility genes to perform sequencing on samples from 60,466 women with breast cancer and 53,461 controls. In separate analyses for protein-truncating variants and rare missense variants in these genes, we estimated odds ratios for breast cancer overall and tumor subtypes. We evaluated missense-variant associations according to domain and classification of pathogenicity.RESULTSProtein-truncating variants in 5 genes (ATM, BRCA1, BRCA2, CHEK2, and PALB2) were associated with a risk of breast cancer overall with a P value of less than 0.0001. Protein-truncating variants in 4 other genes (BARD1, RAD51C, RAD51D, and TP53) were associated with a risk of breast cancer overall with a P value of less than 0.05 and a Bayesian false-discovery probability of less than 0.05. For protein-truncating variants in 19 of the remaining 25 genes, the upper limit of the 95% confidence interval of the odds ratio for breast cancer overall was less than 2.0. For protein-truncating variants in ATM and CHEK2, odds ratios were higher for estrogen receptor (ER)-positive disease than for ER-negative disease; for protein-truncating variants in BARD1, BRCA1, BRCA2, PALB2, RAD51C, and RAD51D, odds ratios were higher for ER-negative disease than for ER-positive disease. Rare missense variants (in aggregate) in ATM, CHEK2, and TP53 were associated with a risk of breast cancer overall with a P value of less than 0.001. For BRCA1, BRCA2, and TP53, missense variants (in aggregate) that would be classified as pathogenic according to standard criteria were associated with a risk of breast cancer overall, with the risk being similar to that of protein-truncating variants.CONCLUSIONSThe results of this study define the genes that are most clinically useful for inclusion on panels for the prediction of breast cancer risk, as well as provide estimates of the risks associated with protein-truncating variants, to guide genetic counseling. (Funded by European Union Horizon 2020 programs and others.)Molecular tumour pathology - and tumour geneticsMTG1 - Moleculaire genetica en pathologie van borstkanke
Нові принципи угоди Базель ІІ
The Basel Committee on Banking Supervision (known as “the Basel Committee”) was established by the central-bank Governors of the group of ten countries at the end of 1974. In 1988 the Basel Committee on Banking Supervision decided to introduce a capital measurement system for a credit risk commonly referred to as the Basel Capital Accord (known as “Basel I”). Amendment to the
Basel Capital Accord to incorporate market risks was issued by the Basel Committee on Banking Supervision, in 1996. The final version of the New Basel Capital Accord (known as “Basel II”), covered operational risk, was released in June 2004. The article, “New capital rules according to
Basel II”, is devoted to the problem risks by credit financial institutions. The paper dedicated to the importance of risks, capital adequacy, risk measurement and risk management, and advantages and disadvantages of the new capital rules are described. The Czech National Bank, a central bank of the Czech Republic, defines the prudential framework for banking business and cooperates with banks to implement the New Basel Capital Accord too. The paper talks about trends and actual situation in accordance with the New Basel Capital Accord and some interesting things being related
to the Czech Republic too.
Базельський комітет з банківського нагляду та регулювання (відомий як “Базельський комітет”) був заснований наприкінці 1974
року управляючими центральними банками групи десяти країн. У 1988 р. Базельський комітет прийняв рішення впровадити систему оцінки капіталу на предмет кредитного ризику, яка отримала назву “Базельська угода про капітал” (Базель І). У 1996 році до цієї угоди було внесено поправку, яка стосувалась ринкових ризиків. Остаточна версія нової Базельської угоди про капітал (Базель ІІ), в якій передбачалось питання операційного ризику, була оприлюднена в червні 2004 року. Дана стаття присвячена проблемі ризиків, з якими стикаються кредитні фінансові установи.
Розглянуто питання ризиків, достатності капіталу, оцінки ризику та управління ним, а також розкрито переваги та недоліки нових
принципів. Національний банк Чеської Республіки, центральний банк країни, визначає доцільну модель банківських операцій та співпрацює з банками з метою втілення в життя Нової Базельської угоди про капітал
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