Ultrasonic impact on a metal melt containing electrostatically charged nanoparticles

Ultrasonic processing is applied to modify nanopowders of metals for the creation of composition alloys. The introduction of particles to metal is prevented by their low wettability in the metal melt. We use electrostatic charging of particles to increase the wettability of particles and to prevent their agglomeration. Mechanisms of the ultrasonic impact on melts of metals containing charged nanoparticles are considered. We find that an electric charge of the surface leads to a decrease in the contact angle. Expressions for the time of ultrasonic processing depending on physical and chemical characteristics of particles and the melt are found

Diffusion coefficient when fine aerosol media propagate in a confined volume

An experimental estimation is reported of the value of the effective diffusion coefficient during aerosol deposition in a confined volume. Aerosol propagation regularities have experimentally been studied in a chamber of a complex configuration with different placement of aerosol generators

Оценка эффективности оперативного лечения больных с хронической критической ишемией нижних конечностей в стадии трофических осложнений

Relevance. Chronic critical ischemia of the lower extremities (CCILE) in the stage of trophic complications is the final stage of diseases of the arteries of the lower extremities, leading to disability of patients and having a poor prognosis in terms of preservation of the lower extremities and mortality.Aim of study. Objective assessment of the efficacy of lower limb revascularization in trophic disorders.Material and methods. The analysis of treatment of 52 patients with stage IV CCILE (according to the classification of R. Fontaine and A.V. Pokrovsky) was carried out. Of these, 42 patients underwent three-phase scintigraphy combined with X-ray computed angiography on a hybrid apparatus. After the operation, this study was conducted in 37 patients.Results. Out of 52 patients, surgery for revascularization of the lower extremities was performed in 37 patients, 15 were not operated on. Out of 37 operated patients, improvement of blood circulation occurred in 32 (86.5%). Circulatory decompensation was observed in 5 patients (9.7%). Among non-operated patients, improvement of blood circulation occurred in 9 patients (17.3%), no effect or decompensation — in 5 (9.7%). Subjective improvement in the condition and decrease in the degree of ischemia corresponded to the improvement of microcirculation according to the data of three-phase scintigraphy.Conclusion.1. Revascularization of the lower extremities in patients with trophic disorders is an effective method of treating this pathology. Therefore, all patients with chronic ischemia threatening limb loss should be considered as candidates for revascularization.2. If the leg arteries or short occlusive or stenotic lesions of the main arteries are affected, such patients should be discussed together with specialists in endovascular surgery for endovascular treatment or joint intervention.3. Hybrid radiation method (three-phase scintigraphy and single-photon emission computed tomography, combined with X-ray computed angiography) is an objective method that reflects the state of peripheral circulation and microcirculation, and allows you to objectively assess the effectiveness of the treatment.Актуальность. Хроническая критическая ишемия нижних конечностей (ХКИНК) в стадии трофических осложнений представляет собой конечную стадию заболеваний артерий нижних конечностей, приводящую к инвалидизации больных и имеющую неблагоприятный прогноз по показателям сохранения нижних конечностей и летальности.Цель исследования. Объективная оценка эффективности реваскуляризации нижних конечностей при трофических расстройствах.Материал и методы. Проведен анализ лечения 52 больных ХКИНК IV стадии (по классификации R. Fontaine и А.В. Покровского). Из них 42 пациентам выполнена трехфазная сцинтиграфия, совмещенная с рентгеновской компьютерной ангиографией на гибридном аппарате. После операции данное исследование проведено 37 пациентам.Результаты. Из 52 пациентов операция по реваскуляризации нижних конечностей выполнена 37 пациентам, не оперированы 15. Из 37 оперированных улучшение кровообращения произошло у 32 (86,5%). Декомпенсация кровообращения отмечена у 5 пациентов (9,7%). Среди неоперированных пациентов улучшение кровообращения произошло у 9 пациентов (17,3%), отсутствие эффекта или декомпенсация — у 5 (9,7%). Субъективное улучшение состояния и снижение степени ишемии соответствовали улучшению микроциркуляции по данным трехфазной сцинтиграфии.Выводы.1. Реваскуляризация нижних конечностей у пациентов с трофическими нарушениями является эффективным методом лечения данной патологии. Поэтому все пациенты с хронической ишемией, угрожающей потерей конечности, должны быть рассмотрены как кандидаты для реваскуляризации.2. При поражении артерий голени или коротких окклюдирующих или стенотических поражениях магистральных артерий такие пациенты должны быть обсуждены совместно со специалистами по рентгенэндоваскулярной хирургии на предмет эндоваскулярного лечения или выполнения вмешательства совместно.3. Гибридный лучевой метод (трехфазная сцинтиграфия и однофотонная эмиссионная компьютерная томография, совмещенная с рентгеновской компьютерной ангиографией) является объективным методом, отображающим состояние периферического кровообращения и микроциркуляции, и позволяет объективно оценить эффективность проведенного лечения

<i>Gaia</i> Data Release 1. Summary of the astrometric, photometric, and survey properties

Context. At about 1000 days after the launch of Gaia we present the first Gaia data release, Gaia DR1, consisting of astrometry and photometry for over 1 billion sources brighter than magnitude 20.7. Aims. A summary of Gaia DR1 is presented along with illustrations of the scientific quality of the data, followed by a discussion of the limitations due to the preliminary nature of this release. Methods. The raw data collected by Gaia during the first 14 months of the mission have been processed by the Gaia Data Processing and Analysis Consortium (DPAC) and turned into an astrometric and photometric catalogue. Results. Gaia DR1 consists of three components: a primary astrometric data set which contains the positions, parallaxes, and mean proper motions for about 2 million of the brightest stars in common with the HIPPARCOS and Tycho-2 catalogues – a realisation of the Tycho-Gaia Astrometric Solution (TGAS) – and a secondary astrometric data set containing the positions for an additional 1.1 billion sources. The second component is the photometric data set, consisting of mean G-band magnitudes for all sources. The G-band light curves and the characteristics of ∼3000 Cepheid and RR-Lyrae stars, observed at high cadence around the south ecliptic pole, form the third component. For the primary astrometric data set the typical uncertainty is about 0.3 mas for the positions and parallaxes, and about 1 mas yr−1 for the proper motions. A systematic component of ∼0.3 mas should be added to the parallax uncertainties. For the subset of ∼94 000 HIPPARCOS stars in the primary data set, the proper motions are much more precise at about 0.06 mas yr−1. For the secondary astrometric data set, the typical uncertainty of the positions is ∼10 mas. The median uncertainties on the mean G-band magnitudes range from the mmag level to ∼0.03 mag over the magnitude range 5 to 20.7. Conclusions. Gaia DR1 is an important milestone ahead of the next Gaia data release, which will feature five-parameter astrometry for all sources. Extensive validation shows that Gaia DR1 represents a major advance in the mapping of the heavens and the availability of basic stellar data that underpin observational astrophysics. Nevertheless, the very preliminary nature of this first Gaia data release does lead to a number of important limitations to the data quality which should be carefully considered before drawing conclusions from the data

Возможности гибридного лучевого метода (трехфазной сцинтиграфии-ОФЭКТ/КТ-ангиографии) в диагностике и стадировании острой ишемии нижних конечностей

ABSTRACT Acute lower limb ischemia (ALLI) is a limb threatening condition with high risk of adverse outcomes. The timely and proper diagnosis of the severity of limb ischemia is crucial in selecting the optimal treatment method.AIM OF STUDY To evaluate the advantages of hybrid imaging in diagnosis of ALLI, patient selection and its severity in order to choose an optimal revascularization method.MATERIAL AND METHODS we examined 163 patients with grade 1–3A ALLI based on I.I. Zatevakhin et al. classification (2002) on a Discovery 670 NM/CT hybrid device, using X-ray (computed tomographic angiography) and radionuclide method (three-phase scintigraphy/single photon emission computed tomography with osteotropic or perfused radiopharmaceutical).RESULTS CT angiography accurately showed level of acute occlusion as well as distal arterial blood flow in all ALLI cases, thus allowing optimal choice of possible revascularization. CT angiography findings alone did not allow optimal staging of ALLI, which is essential for choosing an optimal revascularization method and were considered as supplementary. Three-phase scintigraphy allowed to differentiate the degrees of ALLI based on the visual picture and calculated data, while studies with osteotropic radiopharmaceutical 99mТс-PYP provided information on viability of affected tissues showing the areas of muscle necrosis, compared to perfused radiopharmaceutical.CONCLUSION 1. CT angiography makes it possible to assess in detail the level and severity of occlusive lesions of the arterial system and study the vascular anatomy of the lower limb to resolve the issue of the possibility of revascularization, and also indirectly characterizes the presence of ischemic changes in soft tissues. 2. The radionuclide method (three-phase scintigraphy with an osteotropic radiopharmaceutical/single photon emission computed tomography), performed in addition to computed tomographic angiography, allows not only to detect the presence of ischemic changes in soft tissues, but also to differentiate the degree of acute ischemia of the lower. 3. The hybrid method (three-phase scintigraphy in combination with computed tomographic angiography) contributes to an objective assessment of the state of blood flow in the lower extremities in acute ischemia, both at the main and at the microcirculatoryАКТУАЛЬНОСТЬ Острая ишемия нижних конечностей (ОИНК) – угрожающее жизнеспособности конечности состояние, с высоким риском неблагоприятных исходов. Своевременная и точная диагностика тяжести ишемического повреждения конечности необходима для выбора оптимального метода лечения. ЦЕЛЬ ИССЛЕДОВАНИЯ Проанализировать возможности гибридного метода в диагностике и дифференцировке степеней ОИНК для выбора тактики лечения и отбора пациентов на реваскуляризацию.МАТЕРИАЛ И МЕТОДЫ Обследованы 163 пациента с ОИНК 1-3А степени по классификации И.И. Затевахина и соавт. (2002) на гибридном сканере Discovery 670 NM/CT с использованием рентгенологического (компьютерная томографическая ангиография) и радионуклидного метода (трехфазная сцинтиграфия/однофотонная эмиссионная компьютерная томография с остеотропным либо перфузируемым радиофармпрепаратом).РЕЗУЛЬТАТЫ Компьютерная томографическая ангиография (КТА) позволила во всех случаях выявить причину ОИНК — острую окклюзию и характеризовать дистальное русло для решения вопроса о возможности выполнения реваскуляризации. Признаки, которые оценивались для характеристики магистрального кровотока и состояния тканей конечности при КТА, не позволяли статистически значимо различать степени ОИНК и были расценены как дополнительные. Радионуклидный метод позволял определять степени ОИНК на основании визуальной картины и расчетных данных, при этом исследования с остеотропным радиофармпрепаратом (РФП) 99mТс-пирфотехом предоставляли больше информации благодаря возможности визуализировать зоны мионекроза по сравнению с перфузируемым РФП.ЗАКЛЮЧЕНИЕ Гибридная технология помогает в комплексной диагностике нарушения кровотока нижних конечностей на магистральном и микроциркуляторном уровнях для определения причины и тяжести острого ишемического повреждения конечности. Ее использование способствует выбору оптимальной тактики лечения, решению вопроса о возможности и способах реваскуляризации для сохранения конечности или снижения уровня ампутации, а также своевременного планирования детоксикации.ВЫВОДЫ 1. Компьютерная томографическая ангиография позволяет детально оценить уровень и выраженность окклюзирующего поражения артериального русла и изучить сосудистую анатомию нижней конечности для решения вопроса о возможности реваскуляризации, а также косвенно характеризует наличие ишемических изменений в мягких тканях. 2. Радионуклидный метод (трехфазная сцинтиграфия с остеотропным радиофармпрепаратом/ однофотонная эмиссионная компьютерная томография), выполненный в дополнение к компьютерной томографической ангиографии, позволяет не только выявить наличие ишемических изменений в мягких тканях, но и дифференцировать степень острой ишемии нижних конечностей. 3. Гибридный метод (трехфазная сцинтиграфия в сочетании с компьютерной томографической ангиографией) способствует объективной оценке состояния кровотока в нижних конечностях при острой ишемии как на магистральном, так и на микроциркуляторном уровнях

Factors associated with diversity, quantity and zoonotic potential of ectoparasites on urban mice and voles

Wild rodents are important hosts for tick larvae but co-infestations with other mites and insects are largely neglected. Small rodents were trapped at four study sites in Berlin, Germany, to quantify their ectoparasite diversity. Host-specific, spatial and temporal occurrence of ectoparasites was determined to assess their influence on direct and indirect zoonotic risk due to mice and voles in an urban agglomeration. Rodent-associated arthropods were diverse, including 63 species observed on six host species with an overall prevalence of 99%. The tick Ixodes ricinus was the most prevalent species, found on 56% of the rodents. The trapping location clearly affected the presence of different rodent species and, therefore, the occurrence of particular host-specific parasites. In Berlin, fewer temporary and periodic parasite species as well as non-parasitic species (fleas, chiggers and nidicolous Gamasina) were detected than reported from rural areas. In addition, abundance of parasites with low host-specificity (ticks, fleas and chiggers) apparently decreased with increasing landscape fragmentation associated with a gradient of urbanisation. In contrast, stationary ectoparasites, closely adapted to the rodent host, such as the fur mites Myobiidae and Listrophoridae, were most abundant at the two urban sites. A direct zoonotic risk of infection for people may only be posed by Nosopsyllus fasciatus fleas, which were prevalent even in the city centre. More importantly, peridomestic rodents clearly supported the life cycle of ticks in the city as hosts for their subadult stages. In addition to trapping location, season, host species, body condition and host sex, infestation with fleas, gamasid Laelapidae mites and prostigmatic Myobiidae mites were associated with significantly altered abundance of I. ricinus larvae on mice and voles. Whether this is caused by predation, grooming behaviour or interaction with the host immune system is unclear. The present study constitutes a basis to identify interactions and vector function of rodent-associated arthropods and their potential impact on zoonotic diseases

Gaia Data Release 1: Testing parallaxes with local Cepheids and RR Lyrae stars

Context. Parallaxes for 331 classical Cepheids, 31 Type II Cepheids, and 364 RR Lyrae stars in common between Gaia and the Hipparcos and Tycho-2 catalogues are published in Gaia Data Release 1 (DR1) as part of the Tycho-Gaia Astrometric Solution (TGAS). Aims. In order to test these first parallax measurements of the primary standard candles of the cosmological distance ladder, which involve astrometry collected by Gaia during the initial 14 months of science operation, we compared them with literature estimates and derived new period-luminosity (PL), period-Wesenheit (PW) relations for classical and Type II Cepheids and infrared PL, PL-metallicity (PLZ), and optical luminosity-metallicity (M V -[Fe/H]) relations for the RR Lyrae stars, with zero points based on TGAS. Methods. Classical Cepheids were carefully selected in order to discard known or suspected binary systems. The final sample comprises 102 fundamental mode pulsators with periods ranging from 1.68 to 51.66 days (of which 33 with σ Ω /Ω < 0.5). The Type II Cepheids include a total of 26 W Virginis and BL Herculis stars spanning the period range from 1.16 to 30.00 days (of which only 7 with σ Ω /Ω < 0.5). The RR Lyrae stars include 200 sources with pulsation period ranging from 0.27 to 0.80 days (of which 112 with σ Ω /Ω < 0.5). The new relations were computed using multi-band (V,I,J,K s ) photometry and spectroscopic metal abundances available in the literature, and by applying three alternative approaches: (i) linear least-squares fitting of the absolute magnitudes inferred from direct transformation of the TGAS parallaxes; (ii) adopting astrometry-based luminosities; and (iii) using a Bayesian fitting approach. The last two methods work in parallax space where parallaxes are used directly, thus maintaining symmetrical errors and allowing negative parallaxes to be used. The TGAS-based PL,PW,PLZ, and M V - [Fe/H] relations are discussed by comparing the distance to the Large Magellanic Cloud provided by different types of pulsating stars and alternative fitting methods. Results. Good agreement is found from direct comparison of the parallaxes of RR Lyrae stars for which both TGAS and HST measurements are available. Similarly, very good agreement is found between the TGAS values and the parallaxes inferred from the absolute magnitudes of Cepheids and RR Lyrae stars analysed with the Baade-Wesselink method. TGAS values also compare favourably with the parallaxes inferred by theoretical model fitting of the multi-band light curves for two of the three classical Cepheids and one RR Lyrae star, which were analysed with this technique in our samples. The K-band PL relations show the significant improvement of the TGAS parallaxes for Cepheids and RR Lyrae stars with respect to the Hipparcos measurements. This is particularly true for the RR Lyrae stars for which improvement in quality and statistics is impressive. Conclusions. TGAS parallaxes bring a significant added value to the previous Hipparcos estimates. The relations presented in this paper represent the first Gaia-calibrated relations and form a work-in-progress milestone report in the wait for Gaia-only parallaxes of which a first solution will become available with Gaia Data Release 2 (DR2) in 2018. © ESO, 2017

Gaia Data Release 1: Open cluster astrometry: performance, limitations, and future prospects

Context. The first Gaia Data Release contains the Tycho-Gaia Astrometric Solution (TGAS). This is a subset of about 2 million stars for which, besides the position and photometry, the proper motion and parallax are calculated using Hipparcos and Tycho-2 positions in 1991.25 as prior information.Aims. We investigate the scientific potential and limitations of the TGAS component by means of the astrometric data for open clusters.Methods. Mean cluster parallax and proper motion values are derived taking into account the error correlations within the astrometric solutions for individual stars, an estimate of the internal velocity dispersion in the cluster, and, where relevant, the effects of the depth of the cluster along the line of sight. Internal consistency of the TGAS data is assessed.Results. Values given for standard uncertainties are still inaccurate and may lead to unrealistic unit-weight standard deviations of least squares solutions for cluster parameters. Reconstructed mean cluster parallax and proper motion values are generally in very good agreement with earlier HIPPARCOS-based determination, although the Gaia mean parallax for the Pleiades is a significant exception. We have no current explanation for that discrepancy. Most clusters are observed to extend to nearly 15 pc from the cluster centre, and it will be up to future Gaia releases to establish whether those potential cluster-member stars are still dynamically bound to the clusters.Conclusions. The Gaia DR1 provides the means to examine open clusters far beyond their more easily visible cores, and can provide membership assessments based on proper motions and parallaxes. A combined HR diagram shows the same features as observed before using the HIPPARCOS data, with clearly increased luminosities for older A and F dwarfs

Current status of nuclear cardiology in the Russian Federation

The article is devoted to the analysis of the current status of nuclear cardiology in the Russian Federation. The data on the number of facilities performing radionuclide investigations for the diagnosis and monitoring of the treatment of cardiovascular diseases, their staffing and equipment are given. The statistics of the conducted nuclear cardiology tests for 2018-2020 are given, as well as their methods, features and diagnostic significance are described