565 results on '"IZOTOV, A"'
Search Results
2. Regulation of Stress-Induced Immunosuppression in the Context of Neuroendocrine, Cytokine, and Cellular Processes.
- Author
-
Balakin, Evgenii, Yurku, Ksenia, Ivanov, Mark, Izotov, Alexander, Nakhod, Valeriya, and Pustovoyt, Vasiliy
- Subjects
MOLECULAR mechanisms of immunosuppression ,IMMUNOSUPPRESSION ,CLINICAL medicine ,IMMUNE response ,SCIENTIFIC literature - Abstract
Simple Summary: Understanding the regulatory mechanisms of stress-induced immunosuppression and developing reliable diagnostic methods are important tasks in clinical medicine. This will allow for the development of effective strategies for the prevention and treatment of conditions associated with reduced immune protection against chronic stress. The purpose of this review is to conduct a comprehensive analysis and synthesis of existing data on the regulatory mechanisms of stress-induced immunosuppression. The review is aimed at identifying key neuroendocrine, cytokine, and cellular processes underlying the suppression of the immune response under stress. Understanding the regulatory mechanisms of stress-induced immunosuppression and developing reliable diagnostic methods are important tasks in clinical medicine. This will allow for the development of effective strategies for the prevention and treatment of conditions associated with immune system dysfunction induced by chronic stress. The purpose of this review is to conduct a comprehensive analysis and synthesis of existing data on the regulatory mechanisms of stress-induced immunosuppression. The review is aimed at identifying key neuroendocrine, cytokine, and cellular processes underlying the suppression of the immune response under stress. This study involved a search of scientific literature covering the neuroendocrine, cellular, and molecular mechanisms of stress-induced immunosuppression regulation, as well as modern methods for its diagnosis. Major international bibliographic databases covering publications in biomedicine, psychophysiology, and immunology were selected for the search. The results of the analysis identified key mechanisms regulating stress-induced immunosuppression. The reviewed publications provided detailed descriptions of the neuroendocrine and cytokine processes underlying immune response suppression under stress. A significant portion of the data confirms that the activation of the hypothalamic–pituitary–adrenal (HPA) axis and subsequent elevation of cortisol levels exert substantial immunosuppressive effects on immune cells, particularly macrophages and lymphocytes, leading to the suppression of innate and adaptive immune responses. The data also highlight the crucial role of cortisol and catecholamines (adrenaline and noradrenaline) in initiating immunosuppressive mechanisms under chronic stress. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
3. Extended range proteomic analysis of blood plasma from schizophrenia patients.
- Author
-
Petrovskiy, Denis V., Butkova, Tatiana V., Nikolsky, Kirill S., Kopylov, Arthur T., Nakhod, Valeriya I., Kulikova, Liudmila I., Malsagova, Kristina A., Kibrik, Nikolai D., Rudnev, Vladimir R., Izotov, Alexander A., and Kaysheva, Anna L.
- Published
- 2024
- Full Text
- View/download PDF
4. Sample Preparation for Metabolomic Analysis in Exercise Physiology.
- Author
-
Nakhod, Valeriya I., Butkova, Tatiana V., Malsagova, Kristina A., Petrovskiy, Denis V., Izotov, Alexander A., Nikolsky, Kirill S., and Kaysheva, Anna L.
- Subjects
EXERCISE physiology ,BLOOD testing ,PHENOTYPES ,BIOMOLECULES ,PROTEOMICS ,PERSPIRATION - Abstract
Metabolomics investigates final and intermediate metabolic products in cells. Assessment of the human metabolome relies principally on the analysis of blood, urine, saliva, sweat, and feces. Tissue biopsy is employed less frequently. Understanding the metabolite composition of biosamples from athletes can significantly improve our knowledge of molecular processes associated with the efficiency of training and recovery. Such knowledge may also lead to new management opportunities. Successful execution of metabolomic studies requires simultaneous qualitative and quantitative analyses of numerous small biomolecules in samples under test. Unlike genomics and proteomics, which do not allow for direct assessment of enzymatic activity, metabolomics focuses on biochemical phenotypes, providing unique information about health and physiological features. Crucial factors in ensuring the efficacy of metabolomic analysis are the meticulous selection and pre-treatment of samples. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
5. Biobank Digitalization: From Data Acquisition to Efficient Use.
- Author
-
Bukreeva, Anastasiia S., Malsagova, Kristina A., Petrovskiy, Denis V., Butkova, Tatiana V., Nakhod, Valeriya I., Rudnev, Vladimir R., Izotov, Alexander A., and Kaysheva, Anna L.
- Subjects
BIOLOGICAL specimens ,INDIVIDUALIZED medicine ,ARTIFICIAL intelligence ,BIOBANKS ,MEDICAL research - Abstract
Simple Summary: In recent years, the introduction of a wide range of digital technologies has changed various workflows in the field of biobanking. There are many systems and technologies that can be used in biobanking procedures, medical research and practice. These digital technologies can bring about significant benefits but also a great responsibility. This review discusses the digitalization of biobanking processes, issues related to the benefits of digital biobanks, as well as the challenges that hinder their development. Biobanks are involved in a broad range of studies, including both basic and clinical research, so their functions and roles are evolving. Digital biobanks have emerged due to digitalization in this field; however, it also entails an increasing number of ethical and legal issues, in particular those related to the protection of donor data and potential commercial applications. The development of biobanks and the size of stored datasets lay the groundwork for proceeding to digital biobanks that intensely employ artificial intelligence tools. Digital biobanks can simplify the search for and access to biological specimens, thus contributing to the conduction of research and creating new collaborations. They are becoming an increasingly important tool for personalized medicine and an individualized approach to disease treatment, contributing to the elaboration of more accurate diagnostic methods and the development of innovative therapeutic strategies. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
6. Dependence of winter wheat yield by various precedors on growing conditions in the steppe Crimea.
- Author
-
Izotov, Anatoly M., Tarasenko, Boris A., Dudarev, Dmitry P., and Rogozenko, Anatoly V.
- Published
- 2024
- Full Text
- View/download PDF
7. [Ne v] emission from a faint epoch of reionization-era galaxy: evidence for a narrow-line intermediate-mass black hole.
- Author
-
Chisholm, J, Berg, D A, Endsley, R, Gazagnes, S, Richardson, C T, Lambrides, E, Greene, J, Finkelstein, S, Flury, S, Guseva, N G, Henry, A, Hutchison, T A, Izotov, Y I, Marques-Chaves, R, Oesch, P, Papovich, C, Saldana-Lopez, A, Schaerer, D, and Stephenson, M G
- Subjects
BLACK holes ,GALACTIC evolution ,GALAXY formation ,SUPERGIANT stars ,X-ray binaries ,SEYFERT galaxies - Abstract
Here, we present high spectral resolution |${\it JWST}$| NIRSpec observations of GN 42437, a low-mass (log(M |$_\ast /{\rm M}_\odot)=7.9$|), compact (|$r_e \lt 500$| pc), extreme starburst galaxy at |$z=5.59$| with 13 emission-line detections. GN 42437 has a low metallicity (5–10 per cent Z |$_\odot$|) and its rest-frame H |$\alpha$| equivalent width suggests nearly all of the observed stellar mass formed within the last 3 Myr. GN 42437 has an extraordinary 7 |$\sigma$| significant [Ne v ] 3427 Å detection. The [Ne v ] line has a rest-frame equivalent width of |$11\pm 2$| Å, [Ne v ]/H |$\alpha =0.04\pm 0.007$| , [Ne v ]/[Ne iii ] 3870Å |$= 0.26\pm 0.04$| , and [Ne v ]/He ii 4687Å |$ = 1.2\pm 0.5$|. Ionization from massive stars, shocks, or high-mass X-ray binaries cannot simultaneously produce these [Ne v ] and other low-ionization line ratios. Reproducing the complete nebular structure requires both massive stars and accretion on to a black hole. We do not detect broad lines nor do the traditional diagnostics indicate that GN 42437 has an accreting black hole. Thus, the very high-ionization emission lines powerfully diagnose faint narrow-line black holes at high redshift. We approximate the black hole mass in a variety of ways as log(M |$_{\rm BH}/{\rm M}_\odot) \sim 5{-}7$|. This black hole mass is consistent with local relations between the black hole mass and the observed velocity dispersion, but significantly more massive than the stellar mass would predict. Very high-ionization emission lines may reveal samples to probe the formation and growth of the first black holes in the universe. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
8. Candidate Molecular Biomarkers of Traumatic Brain Injury: A Systematic Review.
- Author
-
Butkova, Tatiana V., Malsagova, Kristina A., Nakhod, Valeriya I., Petrovskiy, Denis V., Izotov, Alexander A., Balakin, Evgenii I., Yurku, Ksenia A., Umnikov, Alexey S., Pustovoyt, Vasiliy I., and Kaysheva, Anna L.
- Subjects
BRAIN injuries ,BRAIN damage ,BLOOD proteins ,NUCLEIC acids ,METABOLITES - Abstract
Traumatic brain injury (TBI) is one of the leading causes of mortality and disability among young and middle-aged individuals. Adequate and timely diagnosis of primary brain injuries, as well as the prompt prevention and treatment of secondary injury mechanisms, significantly determine the potential for reducing mortality and severe disabling consequences. Therefore, it is crucial to have objective markers that indicate the severity of the injury. A number of molecular factors—proteins and metabolites—detected in the blood immediately after trauma and associated with the development and severity of TBI can serve in this role. TBI is a heterogeneous condition with respect to its etiology, clinical form, and genesis, being accompanied by brain cell damage and disruption of blood–brain barrier permeability. Two oppositely directed flows of substances and signals are observed: one is the flow of metabolites, proteins, and nucleic acids from damaged brain cells into the bloodstream through the damaged blood–brain barrier; the other is the infiltration of immune cells (neutrophils and macrophages) and serological proteins. Both flows aggravate brain tissue damage after TBI. Therefore, it is extremely important to study the key signaling events that regulate these flows and repair the damaged tissues, as well as to enhance the effectiveness of treatments for patients after TBI. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
9. Changes in the Cyto- and Fibroarchitectonics of the Cerebellar Cortex in Rats Subjected to Extreme Physical Activity.
- Author
-
Balakin, Evgenii, Yurku, Ksenia, Kuropatkin, Viacheslav, Izotov, Alexander, Nakhod, Valeriya, and Pustovoyt, Vasiliy
- Subjects
GRANULE cells ,INTERNEURONS ,NERVOUS system ,PURKINJE cells ,CELL death ,CEREBELLAR cortex - Abstract
Simple Summary: Physical overexertion surpassing the functional capacity of the nervous system causes the hyperactivation of the neural structures of the cerebellum. In turn, it causes the depletion of intracellular resources and progressive structural changes in cerebellar cells and fibers. After the forced swimming test, animals (n = 30) had significant morphological changes in pyriform cells, granule cells, internuncial neurons, and neuroglial cells. Pronounced degeneration of granular cells was observed, manifested by their fusion into conglomerates. These changes demonstrate that neurodegeneration in the cerebellum takes place in response to physical overexertion. Physical overexertion surpassing the functional capacity of the nervous system causes the hyperactivation of the neural structures of the cerebellum. In turn, it causes the depletion of intracellular resources and progressive structural changes in cerebellar cells and fibers. These degenerative changes may lead to cerebellar dysfunction, including the worsening of coordination, balance, and motor functions. In order to maintain the health and functioning of the cerebellum and the nervous system in general, one needs to avoid physical overexertion and have enough time to recover. Three major types of Purkinje cells were identified in control group animals. After the forced swimming test, animals had significant morphological changes in pyriform cells, granule cells, internuncial neurons, and neuroglial cells. In particular, the extreme degeneration of granule cells was manifested via their fusion into conglomerates. These changes demonstrate that neurodegeneration in the cerebellum takes place in response to physical overexertion. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
10. A Systematic Review of Traumatic Brain Injury in Modern Rodent Models: Current Status and Future Prospects.
- Author
-
Balakin, Evgenii, Yurku, Ksenia, Fomina, Tatiana, Butkova, Tatiana, Nakhod, Valeriya, Izotov, Alexander, Kaysheva, Anna, and Pustovoyt, Vasiliy
- Subjects
BRAIN injuries ,CEREBRAL atrophy ,QUALITY of life ,VALUE (Economics) ,CRANIAL nerves - Abstract
Simple Summary: Traumatic brain injury is a leading cause of death and disability worldwide, according to the Centers for Disease Control and Prevention. It results in various long-term consequences, including brain atrophy, nerve damage, and significant economic costs. Traumatic brain injury is most common among working-age adults, highlighting the urgent need for improved diagnostic and treatment methods. Animal models serve as a valuable tool for studying the mechanisms of traumatic brain injury and developing new treatments. These models allow researchers to control injury parameters and analyze post-traumatic effects, advancing our understanding of the condition. According to the Centers for Disease Control and Prevention (CDC), the national public health agency of the United States, traumatic brain injury is among the leading causes of mortality and disability worldwide. The consequences of TBI include diffuse brain atrophy, local post-traumatic atrophy, arachnoiditis, pachymeningitis, meningocerebral cicatrices, cranial nerve lesions, and cranial defects. In 2019, the economic cost of injuries in the USA alone was USD 4.2 trillion, which included USD 327 billion for medical care, USD 69 billion for work loss, and USD 3.8 trillion for the value of statistical life and quality of life losses. More than half of this cost (USD 2.4 trillion) was among working-age adults (25–64 years old). Currently, the development of new diagnostic approaches and the improvement of treatment techniques require further experimental studies focused on modeling TBI of varying severity. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
11. Linking Mg II and [O II] spatial distribution to ionizing photon escape in confirmed LyC leakers and non-leakers.
- Author
-
Leclercq, Floriane, Chisholm, John, King, Wichahpi, Zeimann, Greg, Jaskot, Anne E., Henry, Alaina, Hayes, Matthew, Flury, Sophia R., Izotov, Yuri, Prochaska, Xavier J., Verhamme, Anne, Amorín, Ricardo O., Atek, Hakim, Bait, Omkar, Blaizot, Jérémy, Carr, Cody, Ji, Zhiyuan, Le Reste, Alexandra, Ferguson, Harry C., and Gazagnes, Simon
- Subjects
GALACTIC redshift ,GALACTIC evolution ,IONIZED gases ,GALAXY formation ,GAS distribution - Abstract
The geometry of the neutral gas in and around galaxies is a key regulator of the escape of ionizing photons. We present the first statistical study aimed at linking the neutral and ionized gas distributions to the Lyman continuum (LyC) escape fraction (f
esc LyC ) in a sample of 22 confirmed LyC leakers and non-leakers at z ≈ 0.35 using the Keck Cosmic Web Imager (Keck/KCWI) and the Low Resolution Spectrograph 2 (HET/LRS2). Our integral field unit data enable the detection of neutral and low-ionization gas, as traced by Mg II, and ionized gas, as traced by [O II], extending beyond the stellar continuum for seven and ten objects, respectively. All but one object with extended Mg II emission also show extended [O II] emission; in this case, Mg II emission is always more extended than [O II] by a factor 1.2 on average. Most of the galaxies with extended emission are non or weak LyC leakers (fesc LyC < 5%), but we find a large diversity of neutral and low-ionization gas configurations around these weakly LyC-emitting galaxies. Conversely, the strongest leakers (fesc LyC > 5%) appear uniformly compact in both Mg II and [O II] with exponential scale lengths ≲1 kpc. Most are unresolved at the resolution of our data. We also find a trend between fesc LyC and the spatial offsets of the nebular gas and the stellar continuum emission. Moreover, we find significant anticorrelations between the spatial extent of the neutral and/or low-ionization gas and the [O III]/[O II] ratio, and Hβ equivalent width, as well as positive correlations with metallicity and UV size, suggesting that galaxies with more compact neutral and/or low-ionization gas sizes are more highly ionized. The observations suggest that strong LyC emitters do not have extended neutral and/or low-ionization gas halos and ionizing photons may be emitted in many directions. Combined with high ionization diagnostics, we propose that the Mg II, and potentially [O II], spatial compactness are indirect indicators of LyC emitting galaxies at high redshift. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
12. Antifouling efficiency of polymer coatings with SeNPs-loaded SiO2(rh)-PHMG composite as antimicrobial agent.
- Author
-
Kharchenko, U., Beleneva, I., Arefieva, O., Egorkin, V., Izotov, N., Vyaliy, I., Nguyen, D. A., Sinebrukhov, S., and Gnedenkov, S.
- Subjects
ENERGY dispersive X-ray spectroscopy ,CONTACT angle ,RICE hulls ,ELASTIC modulus ,TRANSMISSION electron microscopy ,EPOXY coatings - Abstract
Silica from rice husk [SiO
2 (rh)] was used as a mineral base for sequential loading of biogenic selenium nanoparticles (SeNPs) and polyhexamethylene guanidine (PHMG) hydrochloride. As result a filler for polymer coatings with a wide spectrum of antifouling activity was obtained. The complex filler was characterized by scanning electron microscopy, energy dispersive X-ray analysis, and transmission electron microscopy. The filler was introduced into epoxy (EP), polydimethylsiloxane (PDMS), and epoxy-siloxane (EP-PDMS) polymer matrices at 3 wt% and 5 wt% to evaluate their antifouling performance and effect on the durability characteristics of coatings. Characterization of the coatings was performed including water contact angle, surface free energy, pseudo-barnacle adhesion strength and modulus of elasticity. The in vitro antimicrobial properties of the prepared samples were evaluated using Staphylococcus aureus and Candida albicans. Antifouling properties were evaluated in field tests for 7 months. The incorporation of a complex filler involving SeNPs and PHMG made it possible to increase the coating resistance to fouling by 2–5 times. The best results were observed for the EP-PDMS sample with 5 wt% SiO2 (rh)-SeNPs-PHMG characterized by low values of surface free energy (10.3 mN/m) and pseudo-barnacle adhesion strength (0.32 MPa) and acceptable rate of biocidal components release. The results indicate the promising use of the new filler for development of effective antifouling coatings. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
13. The Russian Far East as a Border Macroregion in the Asia-Pacific.
- Author
-
Izotov, D. A.
- Abstract
The Russian Far East serves as a border macroregion for the national economy with countries of the Asia-Pacific Region (APR). All else being equal, the effective realization of the potential of the Russian Far East is possible by reducing the barriers hindering its trade and economic interactions with different markets. Analysis of key development concepts of the Far East has indicated a gradual change in the goals and methods of expanding interactions between the macroregion and Asia-Pacific countries over the past three decades. The first half of the 1990s witnessed the inclusion of Russia in the discussion of different conceptual projects for joint development of the Far East with neighboring countries, including those involving deep economic integration within Northeast Asia (NEA). Later, as centripetal trends in Russia have intensified, development of the Far Eastern economy began to be determined by "resource transit," i.e., extensive use of the transit and natural resource advantages of the Far East based on an exogenous increase in investment in the infrastructure for raw materials export to the Asia-Pacific market. It is shown that under such conditions A significant problem for the Far East is the blockage of effective economic institutions and the formation of an adaptive environment for them, as well as limitation of the optimal functioning of the economy in the export sector and sectors oriented towards the domestic market. An increase in the intensity of trade and economic interactions with the external market is revealed, caused by rapid expansion of the cross-permeability of the macroregional economy with the nearest NEA countries, reflected in the suppressed "autonomy" of the Far Eastern economy and its simplification in 2012–2021. In the current increase in exogenous barriers to the national economy, prerequisites are being created to divert trade flows from the Far East towards China, generating negative effects of forced ties to a single foreign market. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
14. LogNNet Neural Network Application for Diabetes Mellitus Diagnosis.
- Author
-
Izotov, Y. A., Huyut, M. T., and Velichko, A. A.
- Published
- 2024
- Full Text
- View/download PDF
15. High power vacuum ultraviolet source based on gasdynamic ECR plasma.
- Author
-
Lapin, R. L., Skalyga, V. A., Golubev, S. V., Izotov, I. V., Razin, S. V., and Tarvainen, O.
- Subjects
MICROWAVE plasmas ,CYCLOTRON resonance ,PLASMA confinement ,BLOOD volume ,PLASMA density ,ELECTRON plasma ,ALPHA rhythm - Abstract
We report experimental results of vacuum ultraviolet (VUV) emission from the plasma of an electron cyclotron resonance (ECR) discharge in hydrogen, sustained by millimeter-wavelength radiation of a gyrotron. The considered discharge is characterized with the high plasma density (10 13 cm − 3 order of magnitude) and, at the same time, the high electron average energy (10–300 eV), which makes it possible to significantly increase the efficiency of VUV re-emission of the energy deposited into the plasma by the microwave radiation. Experiments were performed with the plasma confined in a simple mirror trap and heated by pulsed gyrotron radiation of 37.5 GHz/100 kW under the ECR condition. The measured volumetric VUV emission power of Lyman-alpha line (122 10 nm) overlapping with the Werner band, Lyman band (160 10 nm), and molecular continuum (180 20 nm) reached 45, 25, and 55 W/cm 3 , respectively. The total absolute radiation power in these three ranges integrated over the plasma volume is estimated to be 22 kW, i.e., 22% of the incident microwave power, which matches theoretical predictions. The development of effective technological VUV sources of a kilowatt power level is expected to be the next step following the optimization of the conditions of the ECR hydrogen discharge sustained by powerful gyrotron radiation. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
16. Exploring the Entropy-Based Classification of Time Series Using Visibility Graphs from Chaotic Maps.
- Author
-
Conejero, J. Alberto, Velichko, Andrei, Garibo-i-Orts, Òscar, Izotov, Yuriy, and Pham, Viet-Thanh
- Subjects
TIME series analysis ,TIME management ,BRAIN-computer interfaces ,NAIVE Bayes classification ,CLASSIFICATION ,SCIENTIFIC community ,MACHINE learning ,ENTROPY - Abstract
The classification of time series using machine learning (ML) analysis and entropy-based features is an urgent task for the study of nonlinear signals in the fields of finance, biology and medicine, including EEG analysis and Brain–Computer Interfacing. As several entropy measures exist, the problem is assessing the effectiveness of entropies used as features for the ML classification of nonlinear dynamics of time series. We propose a method, called global efficiency (GEFMCC), for assessing the effectiveness of entropy features using several chaotic mappings. GEFMCC is a fitness function for optimizing the type and parameters of entropies for time series classification problems. We analyze fuzzy entropy (FuzzyEn) and neural network entropy (NNetEn) for four discrete mappings, the logistic map, the sine map, the Planck map, and the two-memristor-based map, with a base length time series of 300 elements. FuzzyEn has greater GEFMCC in the classification task compared to NNetEn. However, NNetEn classification efficiency is higher than FuzzyEn for some local areas of the time series dynamics. The results of using horizontal visibility graphs (HVG) instead of the raw time series demonstrate the GEFMCC decrease after HVG time series transformation. However, the GEFMCC increases after applying the HVG for some local areas of time series dynamics. The scientific community can use the results to explore the efficiency of the entropy-based classification of time series in "The Entropy Universe". An implementation of the algorithms in Python is presented. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
17. Ion Beam Source Upgrade of the Neutron Source at IAP RAS.
- Author
-
Vybin, S. S., Izotov, I. V., Skalyga, V. A., Palashov, O. V., and Mironov, E. A.
- Subjects
DEUTERIUM ions ,ION beams ,MAGNETIC traps ,NEUTRON sources ,PERMANENT magnets ,NEUTRON generators - Abstract
The results of the ion source of the neutron generator upgrade, which makes it possible to operate in a CW mode, are presented. A magnetic trap consisting of permanent magnets (NdFeB) was developed. A 3-electrode extraction system equipped with a magnetic lens was used to extract the deuterium ion beam. Calculations are made for the formation of a deuterium ion beam with a current over 500 mA and an energy of 100 keV with practically no losses in the extraction system. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
18. Metabolomic and Proteomic Profiling of Athletes Performing Physical Activity under Hypoxic Conditions.
- Author
-
Malsagova, Kristina A., Kopylov, Arthur T., Stepanov, Alexander A., Kulikova, Liudmila I., Izotov, Alexander A., Yurku, Ksenia A., Balakin, Evgenii I., Pustovoyt, Vasiliy I., and Kaysheva, Anna L.
- Subjects
PHYSICAL activity ,PROTEOMICS ,METABOLOMICS ,MALE athletes ,PROTEIN expression - Abstract
Proteomic and metabolomic research enables quantitation of the molecular profile of athletes. Multiomic profiling was conducted using plasma samples collected from 18 male athletes performing aerobic activity (running) at high altitude. Metabolomic profiling detected changes in the levels of 4-hydroxyproline, methionine, oxaloacetate, and tyrosine during the recovery period. Furthermore, proteomic profiling revealed changes in expression of proteins contributing to the function of the immune system, muscle damage, metabolic fitness and performance, as well as hemostasis. Further research should focus on developing metabolic models to monitor training intensity and athlete adaptation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
19. Russia and the challenges of the container transport component of globalization of the economy.
- Author
-
Izotov, O. A., Vasiliev, Yu. I., and Gultyaev, A. V.
- Subjects
CONTAINERIZATION ,UNITIZED cargo systems ,INFRASTRUCTURE (Economics) ,SHIPPING containers ,GLOBALIZATION ,STANDARD of living ,MARITIME shipping - Abstract
The impact of international container transportation on domestic transportation of the Russian Federation at various stages of its economic development has been assessed. The consequences of the introduction of the container in the development of cargo transportation in countries with developed economies over the past seventy years have been revealed. The mechanism of mutual influence of consolidation and strengthening of influence on the economy of countries of international container lines and regions of production and consumption of influence as the basis for the successful functioning of the world economy is considered. It is noted that for countries with a developed standard of living, container transportation is a reflection of the development of the country's economy, since it is an integral part of the well-being of its existence, providing social, professional and spatial exchange of its achievements within the country and with neighboring countries and continents. At the same time, since spatial exchange is also reflected in the development of the transport component and the production capabilities of states, such an exchange in itself is also a powerful impetus for the development of the economies of countries and its transport infrastructure. The role of the level of development of the country's economy in containerization of domestic transportation, at the stages of the appearance of the first prototypes of heavy-duty containers, the functioning of non-contiguous transport systems created by the efforts of interested industries and regions, and during the formation of international container lines, that is, during the globalization of the world economy, is revealed. Using the example of the Russian Federation, it is shown that the economic model that led to the formation of unified world markets is not the only way of development for a country forced to choose solutions aimed at the growth and technological development of its own economy in a period of instability. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
20. Extremely strong C iv λ1550 nebular emission in the extremely low-metallicity star-forming galaxy J2229+2725.
- Author
-
Izotov, Y I, Schaerer, D, Guseva, N G, Thuan, T X, and Worseck, G
- Subjects
DWARF galaxies ,GALAXIES ,OPTICAL spectroscopy ,IONIZING radiation ,SPACE telescopes - Abstract
Using Hubble Space Telescope /Cosmic Origins Spectrograph observations of one of the most metal-poor dwarf star-forming galaxies (SFGs) in the local Universe, J2229+2725, we have discovered an extremely strong nebular C iv λλ1549, 1551 emission-line doublet, with an equivalent width of 43 Å, several times higher than the value observed so far in low-redshift SFGs. Together with other extreme characteristics obtained from optical spectroscopy (oxygen abundance 12 + log(O/H) = 7.085 ± 0.031, ratio O
32 = I ([O iii ]λ5007)/ I ([O ii ]λ3727) ∼ 53, and equivalent width of the H β emission-line EW(H β) = 577 Å), this galaxy greatly increases the range of physical properties for dwarf SFGs at low redshift and is a likely analogue of the high-redshift dwarf SFGs responsible for the reionization of the Universe. We find the ionizing radiation in J2229+2725 to be stellar in origin and the high EW(C iv λλ1549, 1551) to be due to both extreme ionization conditions and a high carbon abundance, with a corresponding log(C/O) = −0.38, that is ∼0.4 dex higher than the average value for nearby low-metallicity SFGs. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
21. Ubiquitous broad-line emission and the relation between ionized gas outflows and Lyman continuum escape in Green Pea galaxies.
- Author
-
Amorín, R. O., Rodríguez-Henríquez, M., Fernández, V., Vílchez, J. M., Marques-Chaves, R., Schaerer, D., Izotov, Y. I., Firpo, V., Guseva, N., Jaskot, A. E., Komarova, L., Muñoz-Vergara, D., Oey, M. S., Bait, O., Carr, C., Chisholm, J., Ferguson, H., Flury, S. R., Giavalisco, M., and Hayes, M. J.
- Subjects
IONIZED gases ,EMISSION-line galaxies ,GALAXIES ,SUPERGIANT stars ,STAR clusters - Abstract
We report observational evidence of highly turbulent ionized gas kinematics in a sample of 20 Lyman continuum (LyC) emitters (LCEs) at low redshift (z ∼ 0.3). Detailed Gaussian modeling of optical emission line profiles in high-dispersion spectra consistently shows that both bright recombination and collisionally excited lines can be fitted as one or two narrow components with intrinsic velocity dispersion of σ ∼ 40 − 100 km s
−1 , in addition to a broader component with σ ∼ 100 − 300 km s−1 , which contributes up to ∼40% of the total flux and is preferentially blueshifted from the systemic velocity. We interpret the narrow emission as highly ionized gas close to the young massive star clusters and the broader emission as a signpost of unresolved ionized outflows, resulting from massive stars and supernova feedback. We find a significant correlation between the width of the broad emission and the LyC escape fraction, with strong LCEs exhibiting more complex and broader line profiles than galaxies with weaker or undetected LyC emission. We provide new observational evidence supporting predictions from models and simulations; our findings suggest that gas turbulence and outflows resulting from strong radiative and mechanical feedback play a key role in clearing channels through which LyC photons escape from galaxies. We propose that the detection of blueshifted broad emission in the nebular lines of compact extreme emission-line galaxies can provide a new indirect diagnostic of Lyman photon escape, which could be useful to identify potential LyC leakers in the epoch of reionization with the JWST. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
22. J1046+4047: an extremely low-metallicity dwarf star-forming galaxy with O32 = 57.
- Author
-
Izotov, Y I, Thuan, T X, and Guseva, N G
- Subjects
DWARF galaxies ,INTERSTELLAR reddening ,STELLAR mass ,STAR formation ,ASTRONOMICAL surveys - Abstract
Using the optical spectrum obtained with the Kitt Peak Ohio State Multi-Object Spectrograph mounted on the Apache Point Observatory 3.5 m Telescope and the Sloan Digital Sky Survey spectrum, we study the properties of one of the most metal-poor dwarf star-forming galaxies (SFGs) in the local Universe, J1046+4047. The galaxy, with a redshift z = 0.04874, was selected from the Data Release 16 of the SDSS. Its properties are among the most extreme for SFGs in several ways. The oxygen abundance 12 + log(O/H) = 7.082 ± 0.016 in J1046+4047 is among the lowest ever observed. With an absolute magnitude M
g = −16.51 mag, a low stellar mass M⋆ = 1.8 × 106 M⊙ , and a very low mass-to-light ratio M⋆ / Lg ∼ 0.0029 (in solar units), J1046+4047 has a very high specific star formation rate sSFR ∼ 430 Gyr−1 , indicating very active ongoing star formation. Another striking feature of J1046+4047 is that it possesses a ratio O32 = I ([O iii ] λ5007)/ I ([O ii ] λ3727) ∼ 57. Using this extremely high O32 , we have confirmed and improved the strong-line calibration for the determination of oxygen abundances in the most metal-deficient galaxies, in the range 12 + log(O/H) ≲ 7.65. This improved method is applicable for all galaxies with O32 ≤ 60. We find the H α emission line in J1046+4047 to be enhanced by some non-recombination processes and thus cannot be used for the determination of interstellar extinction. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
23. Ly α emission in low-redshift most metal-deficient compact star-forming galaxies.
- Author
-
Izotov, Y I, Thuan, T X, Guseva, N G, Schaerer, D, Worseck, G, and Verhamme, A
- Subjects
GALAXIES ,STELLAR mass ,IONIZING radiation ,SPACE telescopes ,DWARF galaxies ,SPECTROGRAPHS - Abstract
We present observations with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope of nine most metal-deficient compact star-forming galaxies with oxygen abundances 12 + log(O/H) = 6.97–7.23, redshifts z = 0.02811–0.13320, and stellar masses M
⋆ ≤ 107 M⊙ . We aim to study the properties of Ly α emission in these extremely metal-deficient objects. We find that all nine galaxies are Ly α emitters (LAEs). We examine various relations between the Ly α escape fraction fesc (Ly α) and other characteristics – such as absolute UV magnitude, oxygen abundance, O32 ratio, stellar mass, Lyman-alpha luminosity, and equivalent width EW(Ly α), ionizing photon production efficiency ξion and velocity separation Vsep between the two peaks of the Ly α profile – of a large sample of LAEs, including our lowest metallicity galaxies and other objects from the literature. We find a relatively tight correlation between fesc (Ly α) and two characteristics, EW(Ly α) and Vsep , whereas no correlation is found between fesc (Ly α) and the oxygen abundance. We also find a relatively tight relation between the Ly α and LyC escape fractions. We propose to use the latter relation to estimate indirectly the escaping ionizing radiation in LAEs, when direct measurements of LyC emission are not possible. We show that the global properties of low- z LAEs are very similar to those of z > 6 galaxies. They are thus ideal local proxies for studying physical processes during the epoch of reionization of the Universe. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
24. The Contribution of the Intestinal Microbiota to the Celiac Disease Pathogenesis along with the Effectiveness of Probiotic Therapy.
- Author
-
Zolnikova, Oxana, Dzhakhaya, Natiya, Bueverova, Elena, Sedova, Alla, Kurbatova, Anastasia, Kryuchkova, Kira, Butkova, Tatyana, Izotov, Alexander, Kulikova, Ludmila, Yurku, Kseniya, Chekulaev, Pavel, and Zaborova, Victoria
- Subjects
GUT microbiome ,CELIAC disease ,PROBIOTICS ,PATHOGENESIS ,HUMAN microbiota - Abstract
The development of many human disorders, including celiac disease (CD), is thought to be influenced by the microbiota of the gastrointestinal tract and its metabolites, according to current research. This study's goal was to provide a concise summary of the information on the contribution of the intestinal microbiota to the CD pathogenesis, which was actively addressed while examining the reported pathogenesis of celiac disease (CD). We assumed that a change in gluten tolerance is formed under the influence of a number of different factors, including genetic predisposition and environmental factors. In related investigations, researchers have paid increasing attention to the study of disturbances in the composition of the intestinal microbiota and its functional activity in CD. A key finding of our review is that the intestinal microbiota has gluten-degrading properties, which, in turn, may have a protective effect on the development of CD. The intestinal microbiota contributes to maintaining the integrity of the intestinal barrier, preventing the formation of a "leaky" intestine. On the contrary, a change in the composition of the microbiota can act as a significant link in the pathogenesis of gluten intolerance and exacerbate the course of the disease. The possibility of modulating the composition of the microbiota by prescribing probiotic preparations is being considered. The effectiveness of the use of probiotics containing Lactobacillus and Bifidobacterium bacteria in experimental and clinical studies as a preventive and therapeutic agent has been documented. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
25. How to accelerate the process of forming a varnish film on rings and collectors of electric machines.
- Author
-
Izotov, A. I., Izotov, S. A., and Fominykh, A. A.
- Subjects
ELECTRIC machines ,ELECTRIC switchgear ,VARNISH & varnishing ,CURRENT distribution ,FRETTING corrosion ,ATMOSPHERIC boundary layer ,SLIDING friction - Abstract
The switching conditions are largely characterized by the specifics of the intermittent nature of the brush contact with each collector plate. The current distribution in the brush contact is determined by the lapping of the working brush to the collector and the state of the varnish film, which determines the nature of the "mirror" on the working surface of the brushes. A varnish film on the working surface of the collector or the current-collecting ring is a prerequisite for ensuring satisfactory switching of electric machines. An important aspect in this regard is the structure of the varnish film. The structure of the varnish film is determined both by the composition of the atmosphere in which it is formed (gas composition, humidity, salinity), and by the electrical processes occurring in intermittent contact in the sliding current collector unit. In some cases, the varnish film may not form and thus significantly degrades the sliding friction and current transfer conditions. Under these conditions, the wear of the brush – collector pairs (current-collecting ring) – increases significantly. Therefore, it is important (in the conditions of a weak protective varnish film or its absence) to use the techniques of its artificial guidance. The article considers a variant of directing a varnish film using an active oxidation catalyst. This solution may be of considerable interest for electric machines operating in the conditions of a discharged atmosphere and the atmosphere of workshops with low oxygen content. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
26. Emotions recognizing using lognnet neural network and Keystroke dynamics dataset.
- Author
-
Velichko, A. and Izotov, Yu.
- Subjects
EMOTION recognition ,EMOTIONS ,EMOTIONAL state ,DATABASES ,MODERN society - Abstract
The development of methods for assessing the emotional state of a person in modern society plays an important role not only in order to increase the efficiency of labor in the workplace or office, but also socially to prevent conflict situations and improve the standard of living. This study presents a method for recognizing human emotions using LogNNet neural network and keystroke dynamics dataset. Two types of training sets were investigated, with 10 and 15 features compiled on the basis of the Emosurv database, an assessment of recognition metrics was given (accuracy, Precision, Recall and F1). It is shown that the accuracy of recognition of one emotion out of 5 (happy, sad, angry, calm, neutral state) reaches 33.4% when using 10 features read only from the keyboard. Such a neural network can be placed on 'Internet of Things' edge devices with low computing resources and RAM up to 3 kB, as well as built into the keyboard using inexpensive controllers such as Arduino. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
27. Associations between Physical Activity and Kyphosis and Lumbar Lordosis Abnormalities, Pain, and Quality of Life in Healthy Older Adults: A Cross-Sectional Study.
- Author
-
Zaborova, Victoria, Zolnikova, Oxana, Dzhakhaya, Natiya, Prokhorova, Svetlana, Izotov, Alexander, Butkova, Tatyana, Pustovoyt, Vasiliy, Yurku, Ksenia, Shestakov, Dmitry, Zaytseva, Tatyana, and Shafaei, Hassan
- Subjects
PAIN ,CROSS-sectional method ,ACCELEROMETERS ,PHYSICAL activity ,KYPHOSIS ,T-test (Statistics) ,LORDOSIS ,QUALITY of life ,DESCRIPTIVE statistics ,RESEARCH funding ,QUESTIONNAIRES ,LUMBAR vertebrae ,DATA analysis software ,OLD age - Abstract
Significant evidence suggests that regular physical activity (PA) leads to numerous physical and psychological outcomes in the elderly. This cross-sectional study was designed to further explore this issue by investigating the associations between PA (measured by accelerometer) and kyphosis and lumbar lordosis abnormalities, pain, and quality of life (QoL) in the elderly. In this cross-sectional study, 163 older adults (73 women) over 65 years of age (mean age: 68.70 ± 3.09) from Russia acted as participants. The following instruments were used to measure research variables: ActiGraph wGT3X-BT for measuring PA, spinal-mouse for measuring kyphosis and lumbar lordosis abnormalities, and the World Health Organization Quality of Life Scale (WHOQOL-BREF) questionnaire for measuring QoL. Pain was measured using two questions. The Independent t-test and a regression analysis were used to analyze data. The results showed that our sample participated on average in 15.8 min of moderate PA (MPA) per day, which is lower than the recommended guidelines. Men were significantly more physically active than women. In addition, MPA was significantly associated with lower kyphosis and lumbar lordosis abnormalities and pain in older adults. Finally, MPA was significantly associated with higher QoL. These findings indicate that PA is a critical concern for the elderly. Accordingly, physical educators and fitness instructors should adopt appropriate strategies to promote an active lifestyle among older adults. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
28. Interaction of Synthetic Cannabinoid Receptor Agonists with Cannabinoid Receptor I: Insights into Activation Molecular Mechanism.
- Author
-
Gavryushov, Sergei, Bashilov, Anton, Cherashev-Tumanov, Konstantin V., Kuzmich, Nikolay N., Burykina, Tatyana I., and Izotov, Boris N.
- Subjects
CANNABINOID receptors ,SYNTHETIC receptors ,TRANSMEMBRANE domains ,MOLECULAR dynamics ,PROTEIN-ligand interactions ,POTENTIAL barrier - Abstract
Synthetic cannabinoid receptor agonists (SCRAs) have become a wide group of new psychoactive substances since the 2010s. For the last few years, the X-ray structures of the complexes of cannabinoid receptor I (CB
1 ) with SCRAs as well as the complexes of CB1 with its antagonist have been published. Based on those data, SCRA–CB1 interactions are analyzed in detail, using molecular modeling and molecular dynamics simulations. The molecular mechanism of the conformational transformation of the transmembrane domain of CB1 caused by its interaction with SCRA is studied. These conformational changes allosterically modulate the CB1 –Gi complex, providing activation of the Gi protein. Based on the X-ray-determined structures of the CB1 –ligand complexes, a stable apo conformation of inactive CB1 with a relatively low potential barrier of receptor activation was modeled. For that model, molecular dynamic simulations of SCRA binding to CB1 led to the active state of CB1 , which allowed us to explore the key features of this activation and the molecular mechanism of the receptor's structural transformation. The simulated CB1 activation is in accordance with the previously published experimental data for the activation at protein mutations or structural changes of ligands. The key feature of the suggested activation mechanism is the determination of the stiff core of the CB1 transmembrane domain and the statement that the entire conformational transformation of the receptor to the active state is caused by a shift of alpha helix TM7 relative to this core. The shift itself is caused by protein–ligand interactions. It was verified via steered molecular dynamics simulations of the X-ray-determined structures of the inactive receptor, which resulted in the active conformation of CB1 irrespective of the placement of agonist ligand in the receptor's active site. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
29. Effect of Radiation Therapy on Composition of Lymphocyte Populations in Patients with Primary Breast Cancer.
- Author
-
Kobzeva, Irina, Astrelina, Tatiana, Suchkova, Yuliya, Malivanova, Tatyana, Usupzhanova, Daria, Brunchukov, Vitaliy, Rastorgueva, Anna, Nikitina, Victoria, Lubaeva, Ekaterina, Sukhova, Marina, Kirilchev, Alexey, Butkova, Tatyana, Izotov, Alexander, Malsagova, Kristina, Samoilov, Alexander, and Pustovoyt, Vasiliy
- Subjects
CANCER patients ,LYMPHOPENIA ,KILLER cells ,RADIOTHERAPY ,LYMPHOCYTES ,EXTERNAL beam radiotherapy - Abstract
Background: Radiation therapy (RT) is an important step in the treatment of primary breast cancer as it is one of the leading contributors to cancer incidence among women. Most patients with this disease acquire radiation-induced lymphopenia in the early post-radiation period; however, little is known about the effect of RT on the composition of lymphocyte populations in such patients. This study was aimed at investigating the effect of adjuvant remote RT—performed in the classical mode for patients with primary breast cancer—on the main components of cell-mediated immunity (major lymphocyte populations), including those in patients receiving chemotherapy. Methods: Between 2020 and 2022, 96 patients with stage I–III breast cancer were included in this study. All patients in the final stage of complex treatment received RT via a 3D conformal technique (3DCRT). The clinical target volume of this RT included the breast or chest wall and locoregional lymphatics. Flow cytometry was used to assess the levels and phenotypes of circulating lymphocytes before and after RT (no more than 7 days before and after RT). The evaluation of the impact of polychemotherapy (PCT) was conducted to determine whether it was a risk factor for the onset of radio-induced lymphopenia (RIL) in the context of RT. Results: When assessing the immune status in the general group of patients (n = 96), before the start of adjuvant external beam radiotherapy (EBRT), the average number of lymphocytes was 1.68 ± 0.064 × 10
9 /L; after the course of adjuvant EBRT, it decreased to 1.01 ± 0.044 × 109 /L (p < 0.001). When assessing the absolute indicators of cellular immunity in the general group of patients with BC after a course of adjuvant EBRT, significant dynamics were revealed by the changes in all cell populations of lymphocytes (paired t-test, p < 0.05). Conclusion: The adaptive immune system in breast cancer patients changed in the early post-radiation period. The absolute levels of B-, T- and natural killer cells significantly reduced after RT regardless of whether the patients previously underwent chemotherapy courses. RT for patients with primary breast cancer should be considered in clinical management because it significantly alters lymphocyte levels and should be considered when assessing antitumor immunity, as significant changes in T-cell immunity have been observed. In addition, the identified changes are critical if specific targeted therapy or immunotherapy is needed. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
30. Determination of rail deformations using fiber optic technologies.
- Author
-
Izotov, Konstantin, Loktev, Daniil, Loktev, Alexey, Karimov, Baktybek, and Salnikova, Alexandra
- Published
- 2023
- Full Text
- View/download PDF
31. Optimization of Proton-Injector Systems for the DARIA Compact Neutron Source.
- Author
-
Vybin, S. S., Izotov, I. V., Mironov, E. A., Palashov, O. V., and Skalyga, V. A.
- Abstract
This work describes improvement of the magnetic trap and beam-formation system of the GISMO (Gas-Dynamic Ion Source for Multipurpose Operation) electron-cyclotron-resonance ion source for its application as a proton injector, which is an integral part of the linear accelerator of a compact neutron source. The magnetic trap is improved and now uses an open design consisting of permanent magnets based on a Nd–Fe–B alloy. This design is optimized to accommodate the extraction system in the part of the plasma chamber with a larger inner diameter compared to the GISMO source. Then, the three-electrode beam-formation system is optimized. The design parameters of the system are developed in such a way that an additional solenoid-shaped magnetic lens can effectively produce a proton beam with a small divergence at the output. Computer simulation proves that this magnetic trap and the extraction system can be used as part of a proton injector for the DARIA project. The next steps in the construction of a proton source are discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
32. Abundances of CNO elements in z ∼ 0.3–0.4 Lyman continuum leaking galaxies.
- Author
-
Izotov, Y I, Schaerer, D, Worseck, G, Berg, D, Chisholm, J, Ravindranath, S, and Thuan, T X
- Subjects
STELLAR initial mass function ,GALAXIES ,INTERSTELLAR medium ,STELLAR mass ,SUPERGIANT stars ,STELLAR winds - Abstract
We present observations with the Space Telescope Imaging Spectrograph onboard the Hubble Space Telescope (HST) of 11 Lyman continuum (LyC) leaking galaxies at redshifts, z , in the range 0.29–0.43, with oxygen abundances 12+log(O/H) = 7.64–8.16, stellar masses M
⋆ ∼ 107.8 –109.8 M⊙ , and O32 = [O iii ] λ5007/[O ii ] λ3727 of ∼ 5–20 aiming to detect the C iii ] λ1908 emission line. We combine these observations with the optical Sloan Digital Sky Survey (SDSS) spectra for the determination of carbon, nitrogen, and oxygen abundances. Our sample was supplemented by 31 galaxies from the literature, for which carbon, nitrogen, and oxygen abundances can be derived from the HST and SDSS spectra. These additional galaxies, however, do not have LyC observations. We find that log(C/O) for the entire sample at 12+log(O/H) < 8.1 does not depend on metallicity, with a small dispersion of ∼0.13 dex around the average value of ∼−0.75 dex. On the other hand, the log(N/O) in galaxies at z > 0.1, including LyC leakers, is systematically higher compared to the rest of the sample with lower metallicity. We find that log(C/O) slightly decreases with increasing M⋆ from ∼ −0.65 at M⋆ = 106 M⊙ to ∼ −0.80 at M⋆ = 109 –1010 M⊙ , whereas log(N/O) is considerably enhanced at M⋆ > 108 M⊙ . The origin of these trends remains basically unknown. A possible solution would be to assume that the upper mass limit of the stellar initial mass function in more massive galaxies is higher. This would result in a higher production of oxygen and a larger fraction of massive stars with stellar wind polluting the interstellar medium with nitrogen. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
33. Vacuum Ultraviolet Emission from a Plasma of Continuous Electron Cyclotron Resonance Discharge.
- Author
-
Lapin, R. L., Golubev, S. V., Skalyga, V. A., Izotov, I. V., Bokhanov, A. F., Kiseleva, E. M., and Vybin, S. S.
- Subjects
CYCLOTRON resonance ,ELECTRON plasma ,MAGNETIC traps ,PLASMA flow ,RADIATION trapping ,FAR ultraviolet radiation - Abstract
We present the results of experimental studies of the intensity of vacuum ultraviolet self-radiation (VUV) of the discharge in hydrogen sustained in an open magnetic trap by the high-power radiation of a gyrotron (frequency f = 28 GHz and power P
gyr = 5 kW) under conditions of electron cyclotron resonance (ECR) in the continuous regime. The optimum system parameters were determined for the generation of VUV radiation by the plasma of the ECR discharge. It was shown that the radiation power in the wavelength range λ = 120–160 nm reaches W = 0.75 kW, which corresponds to an efficiency of η = 20%. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
34. Prospects of general-purpose ports of the Northern Sea Route.
- Author
-
Izotov, O. A. and Vasiliev, Yu. I.
- Subjects
NORTHEAST Passage ,TRANSSHIPMENT ,CARGO handling equipment ,CARGO handling ,BUSINESS planning ,INFRASTRUCTURE (Economics) - Abstract
The influence of the volume of natural resources on the formation of the transport infrastructure necessary for their extraction, processing and shipment in the regions adjacent to the routes of the Northern Sea Route is revealed. It is noted that large corporations successfully implementing plans to develop the natural resources of the Arctic cannot carry out their activities on the basis of general-purpose seaports created in the thirties of the twentieth century and focused mainly on the export of forests, that is, the most easily developed natural wealth of adjacent areas. The capacities of general-purpose ports located on the Arctic coast are not capable of receiving vessels of a modern transport fleet for processing, even for shelter on external raids, are not provided with continuously functioning transport links with the adjacent areas due to the short duration of navigation and accessibility only by winter roads, do not have modern transshipment equipment suitable for handling cargo following in heavy containers. The ways of implementing the plans of large corporations developing the natural resources of the Arctic for the formation of stable cargo flows on the routes of the Northern Sea Route are considered and the possibilities for the implementation of such plans are disclosed. It is emphasized that the functions of seaports as terminals for the shipment of extracted resources and processed products on the routes of the Northern Sea Route cannot be limited only to cargo handling of transport vessels, that is, accumulation and transshipment. Using the example of the considered project of a deep-water hub port near the port of Tiksi, the need for government agencies to participate in the work plans of corporations already at the design stage of the transport infrastructure being created is shown. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
35. Neural Network Entropy (NNetEn): Entropy-Based EEG Signal and Chaotic Time Series Classification, Python Package for NNetEn Calculation.
- Author
-
Velichko, Andrei, Belyaev, Maksim, Izotov, Yuriy, Murugappan, Murugappan, and Heidari, Hanif
- Subjects
TIME series analysis ,PYTHON programming language ,UNCERTAINTY (Information theory) ,DISTRIBUTION (Probability theory) ,ENTROPY - Abstract
Entropy measures are effective features for time series classification problems. Traditional entropy measures, such as Shannon entropy, use probability distribution function. However, for the effective separation of time series, new entropy estimation methods are required to characterize the chaotic dynamic of the system. Our concept of Neural Network Entropy (NNetEn) is based on the classification of special datasets in relation to the entropy of the time series recorded in the reservoir of the neural network. NNetEn estimates the chaotic dynamics of time series in an original way and does not take into account probability distribution functions. We propose two new classification metrics: R2 Efficiency and Pearson Efficiency. The efficiency of NNetEn is verified on separation of two chaotic time series of sine mapping using dispersion analysis. For two close dynamic time series (r = 1.1918 and r = 1.2243), the F-ratio has reached the value of 124 and reflects high efficiency of the introduced method in classification problems. The electroencephalography signal classification for healthy persons and patients with Alzheimer disease illustrates the practical application of the NNetEn features. Our computations demonstrate the synergistic effect of increasing classification accuracy when applying traditional entropy measures and the NNetEn concept conjointly. An implementation of the algorithms in Python is presented. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
36. Probe experiment on basic plasma parameter investigation in a quasi-gasdynamic ion source GISMO.
- Author
-
Polyakov, A. V., Izotov, I. V., Skalyga, V. A., Vybin, S. S., Kiseleva, E. M., and Bokhanov, A. F.
- Subjects
PROTON beams ,ION sources ,CYCLOTRON resonance ,ELECTRON density ,ELECTRON cyclotron resonance sources ,PLASMA temperature ,PLASMA heating - Abstract
Plasma parameters in a 28 GHz gasdynamic continuous electron cyclotron resonance discharge (ECR) with a high volumetric energy input were investigated with a Langmuir probe. The knowledge of the dependencies of plasma density and temperature on external parameters is useful for tuning the ECR source to the desired mode of operation. The design features of the plasma chamber and the configuration of the magnetic field made it possible to use the approximation a non-magnetized flat probe to calculate the temperature and electron density at various gas pressures and power of the heating microwave. A movable tungsten probe was used, allowing for studying plasma parameters along the magnetic field at various distances from the plasma electrode. At high powers, the electron density in the plug turned out to be close to the cutoff density (about 10 13 cm − 3 ). A fraction of warm (> 30 eV) electrons, appearing at high powers, was found, which explains the formation of a pure proton beam in a number of experiments at the same facility. The abrupt increase in the temperature of the warm fraction with power was also found, which makes it of great interest to perform experiments on a multi-charged ions production in heavy gases. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
37. Diagnostics of Hot Electron Component Escaping from Dense Nonequilibrium Plasma of Continuous ECR Discharge.
- Author
-
Kiseleva, E. M., Viktorov, M. E., Skalyga, V. A., Izotov, I. V., Vybin, S. S., Polyakov, A. V., and Bokhanov, A. F.
- Subjects
HOT carriers ,NONEQUILIBRIUM plasmas ,DENSE plasmas ,CYCLOTRON resonance ,PLASMA confinement ,SOLAR radio bursts ,ION sources ,PLASMA instabilities - Abstract
The energy distribution of hot electrons escaping from the plasma of the ion source based on the discharge ignited under conditions of electron cyclotron resonance (ECR) was studied experimentally. The measurements were performed in wide ranges of microwave heating powers and neutral gas pressures. The facility under study is capable of providing uniquely high unit energy input into the plasma confined in the quasi-gas-dynamic (collisional) regime. In the course of the experiments, the diagnostics was performed of microwave radiation generated by the hot fraction of electrons escaping from the plasma. The regimes were discovered, in which the conditions are satisfied for the development of kinetic instabilities in the ECR discharge plasma. The energies are determined of electrons that cause the development of instabilities of this type, which are characterized by bursts of microwave radiation. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
38. LyC Galaxies with Ionizing Radiation Leakage: Properties in the Midinfrared Range Based on Data from the WISE Space Telescope.
- Author
-
Izotova, I. Yu. and Izotov, Yu. I.
- Subjects
IONIZING radiation ,SPACE telescopes ,STELLAR magnitudes ,GALAXIES ,ELECTROMAGNETIC spectrum - Abstract
The photometric characteristics in the midinfrared range of compact galaxies with ionizing radiation leakage (LyC galaxies) are studied to find relationships that would enable the quantitative assessment of the ionizing radiation that goes beyond the galaxy. In particular, the relationships between the color characteristics of galaxies according to data from the WISE space telescope and radiation fraction f
esc (LyC) in the Lyman continuum and radiation fraction fesc (Lyα ) in the Lyα line, which go beyond the galaxy, are investigated. The dependences of fesc (LyC) and fesc (Lyα ) on color index W1–W4 are established from the WISE space telescope data, where W1 and W4 are apparent stellar magnitudes at wavelengths of 3.4 and 22 μm, respectively. This makes color index W1–W4 a useful indicator for quantifying fesc (LyC) and fesc (Lyα ) in addition to the previously established some characteristics of LyC galaxies in the optical and ultraviolet ranges. Thus, the radiation of galaxies in the midinfrared range can be used to search for candidates for leaking LyC galaxies with the purpose of their further observations. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
39. Role of Substituting Manganese for Iron Cations in Changes of the Magnetic and Electrical Characteristics of BiFe1 − xMnxO3 Magnetoelectrics (x = 0.05 and 0.15).
- Author
-
Tarasenko, T. N., Mikhaylov, V. I., Kravchenko, Z. F., Burkhovetskyi, V. V., Izotov, A. I., Legenkii, Yu. A., Zhyvulka, A. M., Yanushkevich, K. I., and Aplesnin, S. S.
- Abstract
In contrast to BiFeO
3 , samples of BiFe1 − x Mnx O3 solid solution (x = 0.05 and 0.15) are ferromagnets and semiconductors. Raising x lowers the Curie temperature (TC = 605 K when x = 0.05 and 550 K when x = 0.15) and increases dielectric permittivity ε at room temperature. The drop in the value of specific magnetization as x rises is due to redistribution of the volumes of ferromagnetic and antiferromagnetic phases. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
40. Preparation of PEO/polymer coatings on aluminum alloy with antifouling properties.
- Author
-
Kharchenko, U., Beleneva, I., Egorkin, V., Vyalyi, I., Izotov, N., Tsvetnikov, A., Karpenko, A., and Nguyen, Chi V.
- Subjects
ALUMINUM alloys ,ACRYLIC coatings ,SURFACE coatings ,POLYMERS ,ETHYL acetate - Abstract
A study on the development of an effective composition of polymeric antifouling coating based on acrylic copolymer with microencapsulated extract of natural origin and superdispersed polytetrafluoroethylene was carried out. A Raman spectroscopy study of the bacterial extract composition showed that the main component was a polyene pigment with 5 conjugated bonds. Encapsulation of ethyl acetate extract of Pseudoalteromonas piscicida 2202 was carried out, two types of microcapsules containing the microbial extract were obtained, and their morphology and efficiency of antifouling action in the coating were studied. Comprehensive studies of antifouling, anticorrosion, and mechanical properties of the coatings allowed identification of the most effective composition providing long-term protection in combination with satisfactory mechanical properties. It is shown that the use of silica nanocapsules with microbial extract in the coating is more effective for enhanced antifouling and mechanical performance. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
41. Kinetic whistler instability in a mirror-confined plasma of a continuous ECR ion source.
- Author
-
Viktorov, M., Izotov, I., Kiseleva, E., Polyakov, A., Vybin, S., and Skalyga, V.
- Subjects
ELECTRON cyclotron resonance sources ,ION sources ,PLASMA instabilities ,CYCLOTRON resonance ,MAGNETIC traps ,ELECTRON distribution - Abstract
Kinetic instabilities in a dense plasma of a continuous electron cyclotron resonance (ECR) discharge in a mirror magnetic trap at the Gasdynamic Ion Source for Multipurpose Operation (GISMO) setup are studied. We experimentally define unstable regimes and corresponding plasma parameters, where the excitation of electromagnetic emission is observed, accompanied by the precipitation of energetic electrons from the magnetic trap. A comprehensive experimental study of the precipitating electron energy distribution and plasma electromagnetic emission spectra, together with theoretical estimates of the cyclotron instability increment proves that under the experimental conditions, the observed instability is related to the excitation of whistler-mode waves, which are a driver of losses of energetic electrons from the magnetic trap. The results of this study are important for the further development of the GISMO electron cyclotron resonance ion source facility and for the improvement of its parameters as an ion source. Also, this research on plasma kinetic instabilities is of fundamental interest and provides experimental tools to simultaneously study plasma electromagnetic activity and corresponding changes in a resonant electron energy distribution. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
42. First Experiments on the Investigation of the Generation of Negative Hydrogen Ions with the Use of CW ECR Discharge at the GISMO Facility.
- Author
-
Lapin, R. L., Skalyga, V. A., Izotov, I. V., Golubev, S. V., Bokhanov, A. F., Kiseleva, E. M., and Vybin, S. S.
- Subjects
ANIONS ,HYDROGEN ions ,CYCLOTRON resonance ,INTERSTITIAL hydrogen generation ,MAGNETIC traps ,MICROWAVE plasmas - Abstract
The results of the first experiments on studying the volume production of negative hydrogen ions using a dense gasdynamic plasma of an electron cyclotron resonance (ECR) discharge sustained by continuous wave (CW) microwave radiation from a gyrotron (28 GHz/5 kW) are described. The ECR hydrogen discharge is ignited in a vacuum chamber placed in a magnetic field created by a system of two consecutive magnetic traps. The system parameters are optimized to obtain the maximum average current density of negative ions at the level of j = 25 mA/cm
2 . The study involves the determination of the negative ion production area, me-asurement of the current density dependences on gas pressure and microwave radiation power, and demonstration of potential optimization opportunities for extraction voltage. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
43. Influence of Sports Training in Foothills on the Professional Athlete's Immunity.
- Author
-
Malsagova, Kristina A., Astrelina, Tatiana A., Balakin, Evgenii I., Kobzeva, Irina V., Adoeva, Elena Ya., Yurku, Kseniya A., Suchkova, Yuliya B., Stepanov, Alexander A., Izotov, Alexander A., Butkova, Tatyana V., Kaysheva, Anna L., and Pustovoyt, Vasiliy I.
- Subjects
PROFESSIONAL athletes ,PHYSICAL training & conditioning ,IMMUNITY ,HUMORAL immunity ,CELLULAR immunity - Abstract
Neuroplasticity and inflammation play important part in the body's adaptive reactions in response to prolonged physical activity. These processes are associated with the cross-interaction of the nervous and immune systems, which is realized through the transmission of signals from neurotransmitters and cytokines. Using the methods of flow cytometry and advanced biochemical analysis of blood humoral parameters, we showed that intense and prolonged physical activity at the anaerobic threshold, without nutritional and metabolic support, contributes to the development of exercise-induced immunosuppression in sportsmen. These athletes illustrate the following signs of a decreased immune status: fewer absolute indicators of the content of leukocytes, lowered values in the immunoregulatory index (CD4
+ /CD8+ ), and diminished indicators of humoral immunity (immunoglobulins A, M, and G, and IFN-γ). These factors characterize the functional state of cellular and humoral immunity and their reduction affects the prenosological risk criteria, indicative of the athletes' susceptibility to develop exercise-induced immunosuppression. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
44. Compact Galaxies with Active Star Formation from the SDSS Data Release 16: Star-Formation Rates Based on the Luminosities of Forbidden Emission Lines in the Optical Range.
- Author
-
Izotova, I. Y. and Izotov, Y. I.
- Subjects
STAR formation ,ACTIVE galaxies ,DATA release ,LUMINOSITY ,GALACTIC redshift ,STELLAR luminosity function - Abstract
We obtained equations for determining the star-formation rate in local compact star-forming galaxies from the SDSS Data Release 16 using luminosities of the forbidden emission lines [O II] λ 372.7 nm, [Ne III] λ 386.8 nm, [O III] λ 495.9 nm, and [O III] λ 500.7 nm and their combinations. The equations are based on the assumption that the star-formation rates, determined from the luminosity of the forbidden lines and H
β emission lines, are equal. This approach is especially useful because the observation of Hβ emission is not always possible. For example, in galaxies with redshift z > 1, this line goes beyond the optical range, and the [O II] λ 372.7 nm line, the [Ne III] λ 386.8 nm line, or their combination can be used instead. On the other hand, in many studies of faint objects using low-resolution spectra, the Hβ line merges with the stronger [O III] λ 495.9 nm and [O III] λ 500.7 nm lines. In these cases, [O III] lines and their combination can be used to determine the rate of star formation. The resulting equations can be applied to compact star-forming galaxies in a wide range of redshifts. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
45. Chromatomass-Spectrometric Method for the Quantitative Determination of Amino- and Carboxylic Acids in Biological Samples.
- Author
-
Kaysheva, Anna L., Kopylov, Arthur T., Stepanov, Alexander A., Malsagova, Kristina A., Izotov, Alexander A., Shurubor, Yevgeniya I., and Krasnikov, Boris F.
- Subjects
CARBOXYLIC acids ,QUADRUPOLE mass analyzers ,METHIONINE ,HYDROCHLORIC acid ,QUANTITATIVE research ,HIGH performance liquid chromatography ,ACID solutions - Abstract
A highly sensitive method for the qualitative and quantitative determination of amino- and carboxylic acids, as well as a number of urea and methionine cycle metabolites in the studied solutions, is presented. Derivatives (esterification) were obtained for amino acids by their reaction in a solution of 3 N of hydrochloric acid in n-butanol for 15 min at 65 °C and for carboxylic acids by their reaction with phenol in ethyl acetate with 3 N of hydrochloric acid for 20 min at 65 °C. Experimental work on the determination of individual metabolites was carried out using the HPLC-MS/MS method and included the creation of a library of spectra of the analyzed compounds and their quantitative determination. Multiplex methods have been developed for the quantitative analysis of the desired metabolites in a wide range of concentrations of 3–4 orders of magnitude. The approach to the analysis of metabolites was developed based on the method of the dynamic monitoring of multiple reactions of the formation of fragments for a mass analyzer with a triple quadrupole (QQQ). The effective chromatographic separation of endogenous metabolites was carried out within 13 min. The calibration curves of the analyzed compounds were stable throughout the concentration range and had the potential to fit below empirical levels. The developed methods and obtained experimental data are of interest for a wide range of biomedical studies, as well as for monitoring the content of endogenous metabolites in biological samples under various pathological conditions. The sensitivity limit of the methods for amino acids was about 4.8 nM and about 0.5 μM for carboxylic acids. Up to 19 amino- and up to 12 carboxy acids and about 10 related metabolites can be tested in a single sample. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
46. An extraction system design with a strongly inhomogeneous electric field for a JYFL electron cyclotron resonance ion source.
- Author
-
Vybin, S. S., Izotov, I. V., and Skalyga, V. A.
- Subjects
ELECTRON cyclotron resonance sources ,ION sources ,ELECTRIC fields ,PLASMA beam injection heating ,PLASMA electrodes ,SYSTEMS design ,SPACE charge - Abstract
A new ECR ion source extraction system has been designed. The design is based on the extraction conditions of the JYFL 14 GHz ECRIS, and its performance is compared to the existing extractor via numerical modeling. The aim is to improve the formation and quality of high-intensity ion beams. The plasma and the puller electrodes shape were changed. The plasma electrode has a narrow tip extruding toward the puller. It causes the electric field to increase near the plasma meniscus and subsequent higher ion velocity growth rate, which leads to the beam space charge reduction at fixed current and acceleration voltage. The extractor was developed with the ion optical code IBSimu. The initial beam parameters were taken from the experimental data. The calculations showed that the new extraction system allows to increase the total extracted current without compromising the beam quality. The new design allows the beam formation optimization for lower extraction voltages overcoming the present space charge limit. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
47. Biogenic synthesis of selenium and tellurium nanoparticles by marine bacteria and their biological activity.
- Author
-
Beleneva, I. A., Kharchenko, U. V., Kukhlevsky, A. D., Boroda, A. V., Izotov, N. V., Gnedenkov, A. S., and Egorkin, V. S.
- Subjects
TELLURIUM ,SELENIUM ,NANOPARTICLES ,NANOPARTICLE size ,MARINE bacteria ,SCANNING electron microscopy ,TELLURITES - Abstract
Selenium (SeNPs) and tellurium nanoparticles (TeNPs) were synthesized by green technology using the three new bacterial marine isolates (strains PL 2476, AF 2469 and G 2451). Isolates were classified as Pseudoalteromonasshioyasakiensis according to 16S rRNA sequence analysis, morphological characteristics, and biochemical reactions. The bioreduction processes of isolates were studied in comparison with the previously described Alteromonasmacleodii (strain 2328). All strains exhibited significant tolerance to selenite and tellurite up to 1000 µg/mL. A comparative analysis of the bioreduction processes of the isolates demonstrated that the strains have a high rate of reduction processes. Characterization of biogenic red SeNPs and black TeNPs using scanning electron microscopy (SEM), EDX analysis, Dynamic Light Scattering, and micro-Raman Spectroscopy revealed that all the isolates form stable spherical selenium and tellurium nanoparticles whose size as well as elemental composition depend on the producer strain. Nanoparticles of the smallest size (up to 100 nm) were observed only for strain PL 2476. Biogenic SeNPs and TeNPs were also characterized and tested for their antimicrobial, antifouling and cytotoxic activities. Significant antimicrobial activity was shown for nanoparticles at relatively high concentrations (500 and 1000 µg/mL), with the antimicrobial activity of TeNPs being more significant than SeNPs. In contrast, against cell cultures (breast cancer cells (SkBr3) and human dermal fibroblasts (HDF) SeNPs showed greater toxicity than tellurium nanoparticles. Studies have demonstrated the high antifouling effectiveness of selenium and tellurium nanoparticles when introduced into self-polishing coatings. According to the results obtained, the use of SeNPs and TeNPs as antifouling additives can reduce the concentration of leachable biocides used in coatings, reducing the pressure on the environment. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
48. Machine Learning Sensors for Diagnosis of COVID-19 Disease Using Routine Blood Values for Internet of Things Application.
- Author
-
Velichko, Andrei, Huyut, Mehmet Tahir, Belyaev, Maksim, Izotov, Yuriy, and Korzun, Dmitry
- Subjects
COVID-19 ,MACHINE learning ,COVID-19 testing ,DIAGNOSIS ,INTERNET of things ,BODY area networks - Abstract
Healthcare digitalization requires effective applications of human sensors, when various parameters of the human body are instantly monitored in everyday life due to the Internet of Things (IoT). In particular, machine learning (ML) sensors for the prompt diagnosis of COVID-19 are an important option for IoT application in healthcare and ambient assisted living (AAL). Determining a COVID-19 infected status with various diagnostic tests and imaging results is costly and time-consuming. This study provides a fast, reliable and cost-effective alternative tool for the diagnosis of COVID-19 based on the routine blood values (RBVs) measured at admission. The dataset of the study consists of a total of 5296 patients with the same number of negative and positive COVID-19 test results and 51 routine blood values. In this study, 13 popular classifier machine learning models and the LogNNet neural network model were exanimated. The most successful classifier model in terms of time and accuracy in the detection of the disease was the histogram-based gradient boosting (HGB) (accuracy: 100%, time: 6.39 sec). The HGB classifier identified the 11 most important features (LDL, cholesterol, HDL-C, MCHC, triglyceride, amylase, UA, LDH, CK-MB, ALP and MCH) to detect the disease with 100% accuracy. In addition, the importance of single, double and triple combinations of these features in the diagnosis of the disease was discussed. We propose to use these 11 features and their binary combinations as important biomarkers for ML sensors in the diagnosis of the disease, supporting edge computing on Arduino and cloud IoT service. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
49. Optical spectroscopy of the extremely metal-deficient star-forming galaxy HSC J1631+4426: a test of the strong-line method.
- Author
-
Thuan, T X, Guseva, N G, and Izotov, Y I
- Subjects
OPTICAL spectroscopy ,TEST methods ,GALAXIES ,DWARF galaxies ,SPECTROGRAPHS ,STARBURSTS - Abstract
Recently, Kojima and co-authors have reported a record low oxygen abundance, 12 + logO/H = 6.90 ± 0.03, or 1.6 per cent of solar metallicity, in the low-mass star-forming galaxy HSC J1631 + 4426. This exceptionally low oxygen abundance was obtained by the direct method, using the [O iii ]λ4363Å emission line. However, using the strong-line method by Izotov et al. (2019b), these authors have derived a significantly higher metallicity 12 + logO/H = 7.175 ± 0.005. To clarify the situation, we have obtained new observations of HSC J1631 + 4426 with the Large Binocular Telescope (LBT)/Multi-Object Dual Spectrograph (MODS). We have derived a higher oxygen abundance, 12 + logO/H = 7.14 ± 0.03, using the direct method, a value similar to the oxygen abundance obtained by the strong-line method. Thus, HSC J1631 + 4426 has a metallicity close to that of the well known blue compact dwarf galaxy I Zw 18. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
50. Lyman alpha and Lyman continuum emission of Mg ii-selected star-forming galaxies.
- Author
-
Izotov, Y I, Chisholm, J, Worseck, G, Guseva, N G, Schaerer, D, and Prochaska, J X
- Subjects
GALAXIES ,IONIZING radiation ,SPACE telescopes ,SEYFERT galaxies ,DWARF galaxies - Abstract
We present observations with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope of seven compact low-mass star-forming galaxies at redshifts, z , in the range 0.3161–0.4276, with various O
3 Mg2 = [O iii ] λ5007/Mg ii λ2796+2803 and Mg2 = Mg ii λ2796/Mg ii λ2803 emission-line ratios. We aim to study the dependence of leaking Lyman continuum (LyC) emission on the characteristics of Mg ii emission together with the dependencies on other indirect indicators of escaping ionizing radiation. LyC emission with escape fractions fesc (LyC) = 3.1–4.6 per cent is detected in four galaxies, whereas only 1σ upper limits of fesc (LyC) in the remaining three galaxies were derived. A strong narrow Lyα emission line with two peaks separated by |$V_{\rm sep}\, \sim$| 298–592 km s−1 was observed in four galaxies with detected LyC emission and very weak Lyα emission is observed in galaxies with LyC non-detections. Our new data confirm the tight anticorrelation between fesc (LyC) and Vsep found for previous low-redshift galaxy samples. Vsep remains the best indirect indicator of LyC leakage among all considered indicators. It is found that escaping LyC emission is detected predominantly in galaxies with Mg |$_2\, \gtrsim$| 1.3. A tendency of an increase of fesc (LyC) with increasing of both the O3 Mg2 and Mg2 is possibly present. However, there is substantial scatter in these relations not allowing their use for reliable prediction of fesc (LyC). [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.