126 research outputs found

    Endoscopic hemostasis in the ulcer gastro-duodenal hemorrhage, using high-frequency biological welding electro-ligature

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    Objective. To improve the efficacy of endoscopic hemostasis for the ulcer gastro-duodenal hemorrhage, using high-frequency biological welding electro-ligature. Materials and methods. In 2017-2020 yrs period the analysis of efficacy of endoscopic hemostasis was done in 160 patients, ageing 40-85 yrs old, for the ulcer gastro-duodenal hemorrhage. The patients were distributed into two groups: the main - 80 patients, in whom high-frequency biological welding electro-ligature was performed, and a control one - 80 patients, in whom monopolar thermal argon-plasm coagulation was conducted. Results. In the main Group a primary hemostasis was achieved in 77 (96.3%) patients. Early recurrence of hemorrhage have occurred in 3 (3.8%) patients. In a control Group a primary hemostasis was achieved in 66 (82.5%) patients. Recurrence of the hemorrhage have occurred in 14 (17.5%) patients. Conclusion. Endoscopic hemostasis for the ulcer gastro-duodenal hemorrhage, using high-frequency biological welding electro-ligature, is achieved due to the impedance action of modulated signal of a high-frequency current as well as the adaptive system of automatic guidance of the welding process and a contact between special endoscopic probe, owing a concave electrode, with bleeding vessel, leading to its complete obliteration. Application of welding electro-ligature for endoscopic hemostasis in the ulcer gastro-duodenal hemorrhage, using high-frequency biological welding electro-ligature, guarantees more secure residual hemostasis, than application of monopolar thermal argon-plasm coagulation, peculiarly in hemorrhage from vessels owing 2 - 4 mm diameter. As a result, the hemorrhage recurrence rate have had reduced down to 3.8% (in the control Group - 18.0%)

    Observations of the luminous red nova AT 2021biy in the nearby galaxy NGC 4631

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    We present an observational study of the luminous red nova (LRN) AT\,2021biy in the nearby galaxy NGC\,4631. The field of the object was routinely imaged during the pre-eruptive stage by synoptic surveys, but the transient was detected only at a few epochs from ∼231\sim 231\,days before maximum brightness. The LRN outburst was monitored with unprecedented cadence both photometrically and spectroscopically. AT\,2021biy shows a short-duration blue peak, with a bolometric luminosity of ∼1.6×1041\sim 1.6 \times 10^{41}\,erg\,s−1^{-1}, followed by the longest plateau among LRNe to date, with a duration of 210\,days. A late-time hump in the light curve was also observed, possibly produced by a shell-shell collision. AT\,2021biy exhibits the typical spectral evolution of LRNe. Early-time spectra are characterised by a blue continuum and prominent H emission lines. Then, the continuum becomes redder, resembling that of a K-type star with a forest of metal absorption lines during the plateau phase. Finally, late-time spectra show a very red continuum (TBB≈2050T_{\mathrm{BB}} \approx 2050 K) with molecular features (e.g., TiO) resembling those of M-type stars. Spectropolarimetric analysis indicates that AT\,2021biy has local dust properties similar to those of V838\,Mon in the Milky Way Galaxy. Inspection of archival {\it Hubble Space Telescope} data taken on 2003 August 3 reveals a ∼20\sim 20\,\msun\ progenitor candidate with log\,(L/L⊙)=5.0(L/{\rm L}_{\odot}) = 5.0\,dex and Teff=5900T_{\rm{eff}} = 5900\,K at solar metallicity. The above luminosity and colour match those of a luminous yellow supergiant. Most likely, this source is a close binary, with a 17--24\,\msun\ primary component.Comment: 21 pages, 14 figures. Accepted by Astronomy and Astrophysic

    Systems protobiology:Origin of life in lipid catalytic networks

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    Life is that which replicates and evolves, but there is no consensus on how life emerged. We advocate a systems protobiology view, whereby the first replicators were assemblies of spontaneously accreting, heterogeneous and mostly non-canonical amphiphiles. This view is substantiated by rigorous chemical kinetics simulations of the graded autocatalysis replication domain (GARD) model, based on the notion that the replication or reproduction of compositional information predated that of sequence information. GARD reveals the emergence of privileged non-equilibrium assemblies (composomes), which portray catalysis-based homeostatic (concentration-preserving) growth. Such a process, along with occasional assembly fission, embodies cell-like reproduction. GARD pre-RNA evolution is evidenced in the selection of different composomes within a sparse fitness landscape, in response to environmental chemical changes. These observations refute claims that GARD assemblies (or other mutually catalytic networks in the metabolism first scenario) cannot evolve. Composomes represent both a genotype and a selectable phenotype, anteceding present-day biology in which the two are mostly separated. Detailed GARD analyses show attractor-like transitions from random assemblies to self-organized composomes, with negative entropy change, thus establishing composomes as dissipative systemstextemdashhallmarks of life. We show a preliminary new version of our model, metabolic GARD (M-GARD), in which lipid covalent modifications are orchestrated by non-enzymatic lipid catalysts, themselves compositionally reproduced. M-GARD fills the gap of the lack of true metabolism in basic GARD, and is rewardingly supported by a published experimental instance of a lipid-based mutually catalytic network. Anticipating near-future far-reaching progress of molecular dynamics, M-GARD is slated to quantitatively depict elaborate protocells, with orchestrated reproduction of both lipid bilayer and lumenal content. Finally, a GARD analysis in a whole-planet context offers the potential for estimating the probability of life's emergence. The invigorated GARD scrutiny presented in this review enhances the validity of autocatalytic sets as a bona fide early evolution scenario and provides essential infrastructure for a paradigm shift towards a systems protobiology view of life's origin

    Forbidden hugs in pandemic times III. Observations of the luminous red nova AT 2021biy in the nearby galaxy NGC 4631

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    We present an observational study of the luminous red nova (LRN) AT 2021biy in the nearby galaxy NGC 4631. The field of the object was routinely imaged during the pre-eruptive stage by synoptic surveys, but the transient was detected only at a few epochs from ∼231 days before maximum brightness. The LRN outburst was monitored with unprecedented cadence both photometrically and spectroscopically. AT 2021biy shows a short-duration blue peak, with a bolometric luminosity of ∼1.6 × 1041 erg s−1, followed by the longest plateau among LRNe to date, with a duration of 210 days. A late-time hump in the light curve was also observed, possibly produced by a shell-shell collision. AT 2021biy exhibits the typical spectral evolution of LRNe. Early-time spectra are characterised by a blue continuum and prominent H emission lines. Then, the continuum becomes redder, resembling that of a K-type star with a forest of metal absorption lines during the plateau phase. Finally, late-time spectra show a very red continuum (TBB ≈ 2050 K) with molecular features (e.g., TiO) resembling those of M-type stars. Spectropolarimetric analysis indicates that AT 2021biy has local dust properties similar to those of V838 Mon in the Milky Way Galaxy. Inspection of archival Hubble Space Telescope data taken on 2003 August 3 reveals a ∼20 M⊙ progenitor candidate with log (L/L⊙) = 5.0 dex and Teff = 5900 K at solar metallicity. The above luminosity and colour match those of a luminous yellow supergiant. Most likely, this source is a close binary, with a 17–24 M⊙ primary component. </p

    Space as a Tool for Astrobiology: Review and Recommendations for Experimentations in Earth Orbit and Beyond

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    Rehabilitation of reproductive function after surgical treatment of common forms of external genital endometriosis

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    The study included 155 women of reproductive age with extended forms of genital endometriosis. The developed algorithm of treatment has improved the reproduction health after treatment this disease
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