Spin state crossover in Co3BO5

We have investigated the spin and oxidation states of Co in Co3BO5 using x-ray magnetic circular dichroism (XMCD) and dc magnetic susceptibility measurements. At low temperatures, XMCD experiments have been performed at the Co K-edge in Co3BO5 and Co2FeBO5 single crystals in the fully ferrimagnetically ordered phase. The Co (K-edge) XMCD signal is found to be related to the Co2+ magnetic sublattices in both compounds, providing strong experimental support for the low-spin (LS) Co3+ scenario. The paramagnetic susceptibility is highly anisotropic. An estimation of the effective magnetic moment in the temperature range 100-250 K correlates well with two Co2+ ions in the high-spin (HS) state and some orbital contribution, while Co3+ remains in the LS state. The crystal structure of the Co3BO5 single crystal has been solved in detail at the T range 296-703 K. The unit cell parameters and volume show anomalies at 500 and 700 K. The octahedral environment of the Co4 site strongly changes with heating. The generalized gradient approximation with Hubbard U correction calculations have revealed that, at low-temperatures, the system is insulating with a band gap of 1.4 eV, and the Co2+ ions are in the HS state, while Co3+ are in the LS state. At high temperatures (T > 700 K), the charge ordering disappears, and the system becomes metallic with all Co ions in 3d7 electronic configuration and HS state. © 2021 American Physical Society

Constraints on the cosmic expansion history from GWTC–3

We use 47 gravitational wave sources from the Third LIGO–Virgo–Kamioka Gravitational Wave Detector Gravitational Wave Transient Catalog (GWTC–3) to estimate the Hubble parameter H(z), including its current value, the Hubble constant H0. Each gravitational wave (GW) signal provides the luminosity distance to the source, and we estimate the corresponding redshift using two methods: the redshifted masses and a galaxy catalog. Using the binary black hole (BBH) redshifted masses, we simultaneously infer the source mass distribution and H(z). The source mass distribution displays a peak around 34 M⊙, followed by a drop-off. Assuming this mass scale does not evolve with the redshift results in a H(z) measurement, yielding ${H}_{0}={68}_{-8}^{+12}\,\mathrm{km}\ \,\ {{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1}$ (68% credible interval) when combined with the H0 measurement from GW170817 and its electromagnetic counterpart. This represents an improvement of 17% with respect to the H0 estimate from GWTC–1. The second method associates each GW event with its probable host galaxy in the catalog GLADE+, statistically marginalizing over the redshifts of each event's potential hosts. Assuming a fixed BBH population, we estimate a value of ${H}_{0}={68}_{-6}^{+8}\,\mathrm{km}\ \,\ {{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1}$ with the galaxy catalog method, an improvement of 42% with respect to our GWTC–1 result and 20% with respect to recent H0 studies using GWTC–2 events. However, we show that this result is strongly impacted by assumptions about the BBH source mass distribution; the only event which is not strongly impacted by such assumptions (and is thus informative about H0) is the well-localized event GW190814

GW190814: gravitational waves from the coalescence of a 23 solar mass black hole with a 2.6 solar mass compact object

We report the observation of a compact binary coalescence involving a 22.2–24.3 Me black hole and a compact object with a mass of 2.50–2.67 Me (all measurements quoted at the 90% credible level). The gravitational-wave signal, GW190814, was observed during LIGO’s and Virgo’s third observing run on 2019 August 14 at 21:10:39 UTC and has a signal-to-noise ratio of 25 in the three-detector network. The source was localized to 18.5 deg2 at a distance of - + 241 45 41 Mpc; no electromagnetic counterpart has been confirmed to date. The source has the most unequal mass ratio yet measured with gravitational waves, - + 0.112 0.009 0.008, and its secondary component is either the lightest black hole or the heaviest neutron star ever discovered in a double compact-object system. The dimensionless spin of the primary black hole is tightly constrained to �0.07. Tests of general relativity reveal no measurable deviations from the theory, and its prediction of higher-multipole emission is confirmed at high confidence. We estimate a merger rate density of 1–23 Gpc−3 yr−1 for the new class of binary coalescence sources that GW190814 represents. Astrophysical models predict that binaries with mass ratios similar to this event can form through several channels, but are unlikely to have formed in globular clusters. However, the combination of mass ratio, component masses, and the inferred merger rate for this event challenges all current models of the formation and mass distribution of compact-object binaries

Возможности аутофлуоресцентной диагностики эпителиальных образований толстой кишки

Objective: to determine the dependence of autofluorescent staining of epithelial colon lesions, depending on the histomorphological structure. Material and Methods: Video colonoscopy using autofluorescence was performed in 1674 patients. The patients’ age was 58±13.9, men were 761 (45.5%), women 913 (54.5%). Epithelial lesions were detected in 269 patients (16%). Endoscopic examinations were carried out according to a standard procedure using Olympus video colonoscopes, GF-260. Results: It was established that the presence of AF staining in the purple color of the epithelial colon lesions, as a marker of dysplasia, can serve as an additional criterion in the complex indications for their endoscopic removal. Conclusion: The developed method of using autofluorescent endoscopy is simple to perform and allows obtaining data that have a differential value on the presence of dysplastic changes in the epithelial colon lesions.Цель исследования: определить зависимость аутофлуоресцентного окрашивания эпителиальных образований толстой кишки в зависимости от гистоморфологического строения. Материалы и методы: Видеоколоноскопия с применением режима аутофлуоресценции была проведена у 1674 пациентов. Возраст пациентов составил 58±13,9, мужчин было 761(45,5%), женщин 913(54,5%). Были выявлены эпителиальные образования у 269 пациентов (16%). Эндоскопические осмотры проводились по стандартной методике, с применением видеоколоноскопов фирмы Олимпас, GF-260 AL. Результаты: Установлено, что присутствие АФ окрашивания в пурпурный цвет эпителиальных образования толстой кишки, как маркера диспалазии, может служить дополнительным критерием в комплексе показаний для их эндоскопического удаления. Заключение: Разработанный метод применения аутофлюоресцентной эндоскопии является простым по выполнению и позволяет получить данные, имеющие дифференциальное значение о наличии диспластических изменений в эпителиальных образованиях толстой кишки

АУТОФЛУОРЕСЦЕНТНАЯ ДИАГНОСТИКА ПОВЕРХНОСТНЫХ ЭПИТЕЛИАЛЬНЫХ НОВООБРАЗОВАНИЙ ЖЕЛУДКА И ТОЛСТОЙ КИШКИ

Autofluorescence staining of SENs of the stomach and colon depends on the morphological structure: carcinomatous and adenomatous structural changes have purple color.Аутофлуоресцентное окрашивание ПЭН желудка и толстой кишки зависит от морфологического строения - карциноматозные и аденоматозные структурные изменения имеют пурпурный цвет