40 research outputs found
Microstructure and mechanical properties of Ti40Nb alloy after severe plastic deformation
The study presents the analysis of microstructure, phase composition and mechanical properties of Ti40Nb alloy exposed to severe plastic deformation. It was shown that isothermal multi-axial forging and further multi-pass rolling intensify the formation of ultra-fine grained structure in the bulk of a billet with the average element size of 0.3 ?m. Such ultra-fine grained structure considerably improves the alloy mechanical properties
H2O MegaMasers: a RadioAstron success story
The RadioAstron space-VLBI mission has successfully detected extragalactic
H2O MegaMaser emission regions at very long Earth to space baselines ranging
between 1.4 and 26.7 Earth Diameters (ED). The preliminary results for two
galaxies, NGC3079 and NGC4258, at baselines longer than one ED indicate
masering environments and excitation conditions in these galaxies that are
distinctly different. Further observations of NGC4258 at longer baselines will
reveal more of the physics of individual emission regions.Comment: To be published in Astrophysical Masers: Unlocking the Mysteries of
the Universe, IAU Symposium 336, 201
The Method of Choosing the Technology for Creating Parallel Special Software With Time Parameterization
Предлагается новый метод выбора технологии создания параллельной программы,
который базируется на том, что написанный один раз параллельный программный код может
быть выполнен разными технологиями параллельного программирования в зависимости
от задач, параметров цикла и имеющейся временной статистики предыдущих запусков. При
этом в процессе работы готовой параллельной программы может применяться один из методов
распараллеливания. Используя теорему Байеса переходим от априорных распределений
на неизвестную величину к апостериорным распределениям. Имеем полную группу
несовместных событий, если нам неизвестны их вероятности до опыта, они равновероятны.
В результате опыта появляется некоторое событие выбора номера технологии и для этого
события известны условные вероятности классификационного выбора. Затем производится
статистический розыгрыш для определения номера выбранной технологииA new method of choosing the technology for creating a parallel program is proposed, which is based on the fact that a parallel program code written once can be executed by different parallel programming technologies, depending on the tasks, cycle parameters and the available time statistics of previous launches. At the same time, one of the parallelization methods can be used during the operation of a ready-made parallel program. Using Bayes' theorem, we move from a priori distributions of unknown magnitude to a posteriori distributions. We have a complete group of incompatible events, if we do not know their probabilities before the experiment, they are equally probable. As a result of the experiment, a certain technology number selection event appears and conditional probabilities of classification selection are known for this event. Then a statistical drawing is made to determine the number of the selected technolog
Phenological shifts of abiotic events, producers and consumers across a continent
Ongoing climate change can shift organism phenology in ways that vary depending on species, habitats and climate factors studied. To probe for large-scale patterns in associated phenological change, we use 70,709 observations from six decades of systematic monitoring across the former Union of Soviet Socialist Republics. Among 110 phenological events related to plants, birds, insects, amphibians and fungi, we find a mosaic of change, defying simple predictions of earlier springs, later autumns and stronger changes at higher latitudes and elevations. Site mean temperature emerged as a strong predictor of local phenology, but the magnitude and direction of change varied with trophic level and the relative timing of an event. Beyond temperature-associated variation, we uncover high variation among both sites and years, with some sites being characterized by disproportionately long seasons and others by short ones. Our findings emphasize concerns regarding ecosystem integrity and highlight the difficulty of predicting climate change outcomes. The authors use systematic monitoring across the former USSR to investigate phenological changes across taxa. The long-term mean temperature of a site emerged as a strong predictor of phenological change, with further imprints of trophic level, event timing, site, year and biotic interactions.Peer reviewe
Chronicles of nature calendar, a long-term and large-scale multitaxon database on phenology
We present an extensive, large-scale, long-term and multitaxon database on phenological and climatic variation, involving 506,186 observation dates acquired in 471 localities in Russian Federation, Ukraine, Uzbekistan, Belarus and Kyrgyzstan. The data cover the period 1890-2018, with 96% of the data being from 1960 onwards. The database is rich in plants, birds and climatic events, but also includes insects, amphibians, reptiles and fungi. The database includes multiple events per species, such as the onset days of leaf unfolding and leaf fall for plants, and the days for first spring and last autumn occurrences for birds. The data were acquired using standardized methods by permanent staff of national parks and nature reserves (87% of the data) and members of a phenological observation network (13% of the data). The database is valuable for exploring how species respond in their phenology to climate change. Large-scale analyses of spatial variation in phenological response can help to better predict the consequences of species and community responses to climate change.Peer reviewe
Management of small agricultural cooperation and corporatization
The possibility of applying the principles of corporate governance in the practice of small agricultural businesses is considered. The authors believe that cooperative associations of small market participants can transform into corporate associations at a certain stage of development. The scientific novelty is represented by an improved economic mechanism of two-level cooperation of small agricultural enterprises with the financial participation of municipalities, regional and Federal authorities and the formation of their own cooperative Bank. The mechanism recommended by the authors is aimed at motivating small business participants to cooperate by the possibility of subsequent corporatization. The implementation of the cooperation development plan will require temporary exemption of its participants from the tax burden, while the state should practice joint construction of processing, logistics and other necessary facilities in the agricultural sector, with the subsequent transfer of its shares to consumer cooperatives of small businesses
Information Bottleneck Analysis of Deep Neural Networks via Lossy Compression
The Information Bottleneck (IB) principle offers an information-theoretic
framework for analyzing the training process of deep neural networks (DNNs).
Its essence lies in tracking the dynamics of two mutual information (MI)
values: one between the hidden layer and the class label, and the other between
the hidden layer and the DNN input. According to the hypothesis put forth by
Shwartz-Ziv and Tishby (2017), the training process consists of two distinct
phases: fitting and compression. The latter phase is believed to account for
the good generalization performance exhibited by DNNs. Due to the challenging
nature of estimating MI between high-dimensional random vectors, this
hypothesis has only been verified for toy NNs or specific types of NNs, such as
quantized NNs and dropout NNs. In this paper, we introduce a comprehensive
framework for conducting IB analysis of general NNs. Our approach leverages the
stochastic NN method proposed by Goldfeld et al. (2019) and incorporates a
compression step to overcome the obstacles associated with high dimensionality.
In other words, we estimate the MI between the compressed representations of
high-dimensional random vectors. The proposed method is supported by both
theoretical and practical justifications. Notably, we demonstrate the accuracy
of our estimator through synthetic experiments featuring predefined MI values.
Finally, we perform IB analysis on a close-to-real-scale convolutional DNN,
which reveals new features of the MI dynamics.Comment: 10 pages, 5 figures, 2 table
Visualization of epithelial cell adhesion molecule-expressing renal cell carcinoma xenografts using designed ankyrin repeat protein Ec1 labelled with Tc-99m and I-125
The upregulation of epithelial cell adhesion molecule (EpCAM) expression, found in a substantial fraction of renal cell carcinomas (RCCs), renders it a potential molecular target for the treatment of disseminated RCC. However, the heterogeneous expression of EpCAM necessitates first identifying the patients with sufficiently high expression of EpCAM in tumors. Using the specific radionuclide-based visualization of EpCAM might enable such identification. The designed ankyrin repeat protein, Ec1, is a small (molecular weight, 18 kDa) targeting protein with a subnanomolar affinity to EpCAM. Using a modified Ec1, a tracer was developed for the radionuclide-based visualization of EpCAM in vivo, i.e., an EpCAM-visualizing designed ankyrin repeat protein (EVD). EVD was labelled with either technetium-99m using technetium tricarbonyl or with iodine-125 (as a surrogate for iodine-123) by coupling it to para-[I-125]iodobenzoyl ([I-125]PIB) groups. Both the I-125-labelled EVD (I-125-EVD) and Tc-99m-labelled EVD (Tc-99m-EVD) bound specifically to EpCAM-expressing SK-RC-52 renal carcinoma cells. The binding affinity (K-D value) of Tc-99m-EVD to SK-RC-52 cells was 400 +/- 28 pM. The tracers' uptake in SK-RC-52 xenografts at 3 h after injection was 5.2 +/- 1.4%ID/g for I-125-EVD and 6.0 +/- 1.4%ID/g for Tc-99m-EVD (no significant difference). These uptake values in SK-RC-52 xenografts were significantly higher (P<0.001) than those in Ramos lymphoma xenografts (used as EpCAM-negative control). The tumor-to-blood uptake ratio was significantly higher for Tc-99m-EVD (25 +/- 6) compared with that of I-125-EVD (14 +/- 3). However, I-125-EVD was associated with higher tumor-to-liver, tumor-to-salivary gland, tumor-to-spleen and tumor-to-intestinal wall ratios. This makes it the preferable tracer for visualizing EpCAM expression levels in the frequently occurring abdominal metastases of RCC
Epithelial cell adhesion molecule-targeting designed ankyrin repeat protein-toxin fusion Ec1-LoPE exhibits potent cytotoxic action in prostate cancer cells
Targeted anticancer therapeutics offer the advantage of reducing cytotoxic side effects to normal cells by directing the cytotoxic payload selectively to cancer cells. Designed ankyrin repeat proteins (DARPins) are promising non-immunoglobulin-based scaffold proteins for payload delivery to cancer-associated molecular targets. Epithelial cell adhesion molecule (EpCAM) is overexpressed in 40-60% of prostate cancers (PCs) and is associated with metastasis, increased risk of PC recurrence and resistance to treatment. Here, we investigated the use of DARPin Ec1 for targeted delivery of Pseudomonas exotoxin A variant (LoPE) with low immunogenicity and low non-specific toxicity to EpCAM-expressing prostate cancer cells. Ec1-LoPE fusion protein was radiolabeled with tricarbonyl technetium-99m and its binding specificity, binding kinetics, cellular processing, internalization and cytotoxicity were evaluated in PC-3 and DU145 cell lines. Ec1-LoPE showed EpCAM-specific binding to EpCAM-expressing prostate cancer cells. Rapid internalization mediated potent cytotoxic effect with picomolar IC50 values in both studied cell lines. Taken together, these data support further evaluation of Ec1-LoPE in a therapeutic setting in a prostate cancer model in vivo
Indirect Radioiodination of DARPin G3 Using N-succinimidyl-Para-Iodobenzoate Improves the Contrast of HER2 Molecular Imaging
Radionuclide molecular imaging of human epidermal growth factor receptor 2 (HER2) in breast and gastroesophageal cancer might be used to stratify patients for HER2-targeted therapy as well as monitor treatment response and disease progression. Designed ankyrin repeat proteins (DARPins) are small engineered scaffold proteins with favorable properties for molecular imaging. Herein we compared two methods for labeling the anti-HER2 DARPin (HE)(3)-G3, direct and indirect radioiodination. We hypothesized that the use of N-succinimidyl-para-iodobenzoate (SPIB) for radioiodination would facilitate the clearance of radiometabolites and improve the contrast of imaging. Both radiolabeled (HE)(3)-G3 variants preserved their binding specificity and high affinity to HER2-expressing cells. The specificity of tumor targeting in vivo was also demonstrated. A biodistribution comparison of [I-125]I-(HE)(3)-G3 and [I-125]I-PIB-(HE)(3)-G3, in mice bearing HER2 expressing SKOV3 xenografts, showed rapid clearance of [I-125]I-PIB-(HE)(3)-G3 from normal organs and tissues and low accumulation of activity in organs with NaI-symporter expression. Both radiolabeled (HE)(3)-G3 variants had equal tumor uptake. Consequently, the indirect label provided higher tumor-to-blood and tumor-to-organ ratios compared with the direct label. Comparative Single Photon Emission Computed Tomography (SPECT)/CT imaging of HER2 expression in SKOV3 xenografts, using both radiolabeled DARPins, demonstrated the superior imaging contrast of the indirect label. Indirect radioiodination of (HE)(3)-G3 using SPIB could be further applied for SPECT and PET imaging with iodine-123 and iodine-124