Supernova Ia: a Converging Delayed Detonation Wave

A model of a carbon-oxygen (C--O) presupernova core with an initial mass 1.33 M_\odot, an initial carbon mass fraction 0.27, and with an average mass growth-rate 5 x 10^{-7} M_\odot/yr due to accretion in a binary system was evolved from initial central density 10^9 g/cm^3, and temperature 2.05 x 10^8 K through convective core formation and its subsequent expansion to the carbon runaway at the center. The only thermonuclear reaction contained in the equations of evolution and runaway was the carbon burning reaction 12C + 12C with an energy release corresponding to the full transition of carbon and oxygen (with the same rate as carbon) into 56Ni. As a parameter we take \alpha_c - a ratio of a mixing length to the size of the convective zone. In spite of the crude assumptions, we obtained a pattern of the runaway acceptable for the supernova theory with the strong dependence of its duration on \alpha_c. In the variants with large enough values of \alpha_c=4.0 x 10^{-3} and 3.0 x 10^{-3} the fuel combustion occurred from the very beginning as a prompt detonation. In the range of 2.0 x 10^{-3} >= \alpha_c >= 3.0 x 10^{-4} the burning started as a deflagration with excitation of stellar pulsations with growing amplitude. Eventually, the detonation set in, which was activated near the surface layers of the presupernova (with m about 1.33 M_\odot) and penetrated into the star down to the deflagration front. Excitation of model pulsations and formation of a detonation front are described in detail for the variant with \alpha_c=1.0 x 10^{-3}.Comment: 13 pages, 11 figures, to appear in Astronomy Letter

Dynamics and Radiation of Young Type-Ia Supernova Remnants: Important Physical Processes

We examine and analyze the physical processes that should be taken into account when modeling young type-Ia SNRs, with ages of several hundred years. It is shown, that energy losses in the metal-rich ejecta can be essential for remnants already at this stage of evolution. The influence of electron thermal conduction and the rate of the energy exchange between electrons and ions on the temperature distribution and the X-radiation from such remnants is studied. The data for Tycho SNR from the XMM-Newton X-ray telescope have been employed for the comparison of calculations with observations.Comment: 19 pages, 8 figure

The origin of intergalactic thermonuclear supernovae

The population synthesis method is used to study the possibility of explaining the appreciable fraction (20^+12_15%) of the intergalactic (no-host) type Ia supernovae observed in galaxy clusters (Gal-Yam ete al. 2003) by binary whote dwarf merginngs in the cores of globular clusters. In a typical globular cluster, the number of merging double white dwarfs is fount to be smaller than 10^{-13} per year per average cluster star during the entire evolution of the cluster, which is a factor of 3 higher than in a Milky-Way-type galaxy. From 5 to 30% of the merging white dwarfs are dynamically expelled from the cluster with barycenter velocities up to 150 km/s. SN Ia explosions during the mergers of binary white dwarfs in dense star clusters may account for \sim 1% of the total rate of SN Ia in the central parts of galaxy clusters if the baryon mass fraction in such star clusters is \sim 0.3%.Comment: 8 pages, 3 figs. Astronomy Letters (in press

Synthesis and electrochemical properties of Composite galvanic Ni with carbon nanomaterials and PVD Mo coatings

Двойной слой покрытия Ni - МО получен путем электролитического осаждения гальванического никеля и осаждения PVD-покрытия. Исследованы также ионные покрытия на фольге Ni и композиционные электролитические покрытия Ni с углеродными наноматериалами (CNM), нанесенными на мягкую сталь. Такие покрытия исключают гидрогенизацию Ni-основы в щелочном растворе и обладают повышенными электрокаталитическими свойствами при выделении водорода и окислителя. Наличие углеродных наноматериалов в комбинированных покрытиях является причиной активного поглощения водорода после катодной поляризации. Происходит формирование на поверхностном слое твердого раствора наноструктуры (Ni, Mo) после обработки потоков плазмы сжатия с фиксированными параметрами паттернов Мо / Ni / слабая сталь

Inhibition of O-GlcNAc transferase activates tumor-suppressor gene expression in tamoxifen-resistant breast cancer cells

In this study, we probed the importance of O-GlcNAc transferase (OGT) activity for the survival of tamoxifen-sensitive (TamS) and tamoxifen-resistant (TamR) breast cancer cells. Tamoxifen is an antagonist of estrogen receptor (ERa), a transcription factor expressed in over 50% of breast cancers. ERa-positive breast cancers are successfully treated with tamoxifen; however, a significant number of patients develop tamoxifen-resistant disease. We show that in vitro development of tamoxifenresistance is associated with increased sensitivity to the OGT small molecule inhibitor OSMI-1. Global transcriptome profiling revealed that TamS cells adapt to OSMI-1 treatment by increasing the expression of histone genes. This is known to mediate chromatin compaction. In contrast, TamR cells respond to OGT inhibition by activating the unfolded protein response and by significantly increasing ERRFI1 expression. ERRFI1 is an endogenous inhibitor of ERBB-signaling, which is a known driver of tamoxifen-resistance. We show that ERRFI1 is selectively downregulated in ERa-positive breast cancers and breast cancers driven by ERBB2. This likely occurs via promoter methylation. Finally, we show that increased ERRFI1 expression is associated with extended survival in patients with ERa-positive tumors (p = 9.2e-8). In summary, we show that tamoxifen-resistance is associated with sensitivity to OSMI-1, and propose that this is explained in part through an epigenetic activation of the tumor-suppressor ERRFI1 in response to OSMI-1 treatment.Peer reviewe

Сочетанное применение эритропоэтина и препаратов железа для коррекции постгеморрагической анемии у родильниц: систематический обзор и метаанализ

АКТУАЛЬНОСТЬ: Относительно эффективности эритропоэтина в сочетании с пероральной ферротерапией для коррекции послеродовой анемии имеются ограниченные данные. ЦЕЛЬ ИССЛЕДОВАНИЯ: Оценить эффективность эритропоэтина в сочетании с пероральными добавками железа по сравнению с пероральной ферротерапией у родильниц, перенесших послеродовое кровотечение. МАТЕРИАЛЫ И МЕТОДЫ: В MEDLINE, Scopus, EBSCOhost и 5 других базах (с января 1980 г. по февраль 2023 г.) проведен поиск статей о применении пероральных препаратов железа в комбинации с эритропоэтином и без него для лечения постгеморрагической анемии у родильниц. Первичные конечные точки: уровень гемоглобина, прирост гемоглобина, гематокрит, число гемотрансфузий, вторичные: уровень ферритина, сывороточного железа, способность к лактации. Анализ выполнен в соответствии с руководством PRISMA, 2020. РЕЗУЛЬТАТЫ: Проанализировано 4 исследования, 198 женщин. При использовании эритропоэтина в сочетании с пероральной ферротерапией накопленное значение прироста концентрации гемоглобина через 5 дней, 2 нед. от начала лечения значимо выше по сравнению с контролем (разность средних, mean difference [MD] 11,83 г/л, 95%-й доверительный интервал [95% ДИ] 4,43–19,23; p = 0,002; MD 10,13 г/л; 95% ДИ 4,97–15,29; р = 0,0001) соответственно. Накопленное среднее значение концентрации гемоглобина через 40 дней значимо выше в группе эритропоэтина (MD 11,00 г/л, 95% ДИ 1,70–20,30; р = 0,02). Накопленное среднее значение гематокрита через 2 нед. значимо выше в группе эритропоэтина (MD 3,35 %, 95% ДИ 0,31–6,39); р = 0,03). Применение эритропоэтина в комбинации с пероральной ферротерапией снижает вероятность гемотрансфузии (относительный риск 0,12, 95% ДИ 0,02–0,95; р = 0,04). ВЫВОДЫ: Показан более быстрый гематологический ответ при сочетанном применении эритропоэтина с пероральной ферротерапией по сравнению с монотерапией препаратами железа при коррекции постгеморрагической анемии у родильниц. Требуются дальнейшие исследования с достаточными объемами выборок

Assessment of adaptability and potential productivity of spring soft wheat in the conditions of the Ryazan region

The article gives a comprehensive assessment of 5 varieties (Lada, Agata, RIMA, Arcea, Maestro) and 5 breeding lines of spring soft wheat according to the yield and adaptive properties. The studies were carried out in 2018-2022 in the conditions of the Ryazan region on dark gray forest soil. The potential for productivity and adaptability was determined according to the method of L. A. Zhivotkov et al., the degree of yield variation (СV, %) – according to B. A. Dospekhov,  the yield range (d, %) – according to V. A. Zykin, index of stability (L') – according to A. A. Gryaznov, the indicator of the level of stability of the yield of a variety (PUSS) – according to E. D. Nettevich et al., ecological plasticity (bi), stability of yield (σ2d) and index of environment conditions (Ij) – according to S. A. Eberhart and W. A. Russell. It has been established that on average for 2018-2022 the highest yield potential was noted in the varieties Arcea (5.19 t/ha), Maestro (5.69 t/ha) and line  268 (5.33 t/ha). It was revealed that the productivity of the Maestro variety and line 268 was higher than the average varietal both under favorable conditions of 2022 (Ij = +6.2) – by 16.3 and 9.7 %, and under unfavorable dry conditions of 2019  (Ij = -5.4) – by 22.0 and 24.5 %, respectively. The productivity of the Arcea variety under conditions of severe drought was 99.1 % of the average varietal, which indicates good adaptive properties. As the result of the assessment by the linear regression coefficient (bi), it has been established that the varieties RIMA, Agata, Lada, Arcea actively respond to the improvement of external environmental factors (bi = 1.23; 1.35; 1.43; 1.52, respectively). According to the results of a comprehensive assessment of adaptive properties, the Maestro variety and line 898 were distinguished, which were characterized by a relatively stable yield (СV – 9.3 and 5.2%; σ2d  – 7.71 and 9.09; L' – 6.12 and 9.44; PUSS – 209.6 and 176.5 %, respectively) and high adaptability to environmental conditions (CA – 1.17 and 1.01, respectively)

Neutron stars in globular clusters: formation and observational manifestations

Population synthesis is used to model the number of neutron stars in globular clusters that are observed as LMXBs and millisecond PSRs. The dynamical interaction between binary and single stars in a GC are assumed to take place with a permanently replenished "background" of single stars whose density distribution keeps track with the cluster evolution as a whole and evolution of single stars. We use the hypothesis (Podsiadlowski et al) that NS forming in binary systems from components with initial masses \sim 8-12 M_\odot during the electron-capture collapse of the degenerate O-Ne-Mg core do not acquire a high space velocities (kicks). The remaining NSs (i.e. from single stars with M>8 M_\odot or binary comonents with M>12 M_\odot) are assumed to be born with high kicks, as found from obsrevations of single pulsars (Hobbs et al. 2005). Under this assumption, a sizeable fraction of NSs remain in GCs (about 1000 NSs in a GC with a mass of 5\times 10^5 M_\odot). The number of ms PSRs formed in the cluster via accretion spin-up in binaries is then about 10, which is consistent with observations. Our modelling reproduces the observed shape of the X-ray luminosity function for accreting NSs in binaries with normal and degenerate components and the distribution of spin periods of ms PSRs in GCs under the assumption of accretion-driven magnetic field decay of NSs up to a bottom value of 10^8 G. The number of LMXBs and ms PSRs dynamically expelling from GCs is also calculated.Comment: LATEX, 21 pages, 8 gif figures, Astronomy Letters, in pres