Dust extinction and absorption: the challenge of porous grains

In many models of dusty objects in space the grains are assumed to be composite or fluffy. However, the computation of the optical properties of such particles is still a very difficult problem. We analyze how the increase of grain porosity influences basic features of cosmic dust -- interstellar extinction, dust temperature, infrared bands and millimeter opacity. Porous grains can reproduce the flat extinction across the 3 - 8 \mkm wavelength range measured for several lines of sight by {\it ISO} and {\it Spitzer}. Porous grains are generally cooler than compact grains. At the same time, the temperature of very porous grains becomes slightly larger in the case of the EMT-Mie calculations in comparison with the results found from the layered-sphere model. The layered-sphere model predicts a broadening of infrared bands and a shift of the peak position to larger wavelengths as porosity grows. In the case of the EMT-Mie model variations of the feature profile are less significant. It is also shown that the millimeter mass absorption coefficients grow as porosity increases with a faster growth occurring for particles with Rayleigh/non-Rayleigh inclusions. As a result, for very porous particles the coefficients given by two models can differ by a factor of about 3. It is found that an increase of porosity leads to an increase of extinction cross sections at some wavelengths and a decrease at others depending on the grain model. However, this behaviour is sufficient to reproduce the extinction curve in the direction of the star $\sigma$ Sco using current solar abundances. In the case of the star $\zeta$ Oph our model requires larger amounts of carbon and iron in the dust-phase than is available.Comment: Astronomy and Astrophysics (accepted; 11 pages, 11 figures

New Interstellar Extinction Maps Based on Gaia and Other Sky Surveys

We present new three-dimensional (3D) interstellar extinction maps in the $V$ and Gaia $G$ filters within 2 kpc of the Sun, a 3D differential extinction (dust spatial distribution density) map along the lines of sight in the same space, a 3D map of variations in the ratio of the extinctions in the $V$ and Gaia $G$ filters within 800 pc of the Sun, and a 2D map of total Galactic extinction through the entire dust half-layer from the Sun to extragalactic space for Galactic latitudes $|b|>13^{\circ}$. The 3D maps have a transverse resolution from 3.6 to 11.6 pc and a radial resolution of 50 pc. The 2D map has an angular resolution of 6.1 arcmin. We have produced these maps based on the Gaia DR3 parallaxes and Gaia, Pan-STARRS1, SkyMapper, 2MASS, and WISE photometry for nearly 100 million stars. We have paid special attention to the space within 200 pc of the Sun and high Galactic latitudes as regions where the extinction estimates have had a large relative uncertainty so far. Our maps estimate the extinction within the Galactic dust layer from the Sun to an extended object or through the entire dust half-layer from the Sun to extragalactic space with a precision $\sigma(A_\mathrm{V})=0.06$ mag. This gives a high relative precision of extinction estimates even at high Galactic latitudes, where, according to our estimates, the median total Galactic extinction through the entire dust half-layer from the Sun to extragalactic objects is $A_\mathrm{V}=0.12\pm0.06$ mag. We have shown that the presented maps are among the best ones in data amount, space size, resolution, precision, and other properties.Comment: 15 pages, 4 table

Low-frequency dynamics of disordered XY spin chains and pinned density waves: from localized spin waves to soliton tunneling

A long-standing problem of the low-energy dynamics of a disordered XY spin chain is re-examined. The case of a rigid chain is studied where the quantum effects can be treated quasiclassically. It is shown that as the frequency decreases, the relevant excitations change from localized spin waves to two-level systems to soliton-antisoliton pairs. The linear-response correlation functions are calculated. The results apply to other periodic glassy systems such as pinned density waves, planar vortex lattices, stripes, and disordered Luttinger liquids.Comment: (v2) Major improvements in presentation style. One figure added (v3) Another minor chang

Phosphine-catalyzed addition of P(O)-H compounds to ethyl phenylpropiolate

© 2015 Elsevier Ltd. An efficient PBu3-catalyzed α-addition of the P(O)-H bond to ethyl phenylpropiolate has been developed. This strategy offers a facile method for the preparation of synthetically useful alkenyl phosphonates and phosphinates proceeding under neutral reaction conditions with high atom economy

The pudovik reaction catalyzed by tertiary phosphines

© 2016 Bentham Science Publishers.Conjugate addition of dialkyl phosphites and ethyl phenylphosphinate to electron-deficient alkenes containing ester, nitrile or amide group under PBu3 catalysis afforded corresponding phosphonates and phosphinates in high yields within short reaction times. Under the optimized conditions developed, the chemistry was free from side reactions involving competitive phosphine-catalyzed dimerization of the activated alkene. Long chain alkyl groups in the phosphite were well tolerated in this transformation. The catalytic activity of PBu3 was far superior to that of tertiary amines. High efficiency, mild reaction conditions, and ease of the catalyst recovery make the proposed procedure competitive with the classical base-promoted reaction

Адъювантная внутрипузырная химиотерапия с аквакомплексом глицеросольвата титана в сравнении с БЦЖ-терапией у больных немышечно-инвазивным раком мочевого пузыря высокого риска

Objective: to compare recurrence rate, progression rate and recurrence-free survival in patients with high-risk non-muscle-invasive bladder cancer (NMIBC) after adjuvant intravesical chemotherapy (IVCT) with titanium glycerosolvate aquacomplex (TGA) versus intravesical BCG therapy.Material and methods. In a retrospective multicenter clinical study initially were included 126 patients with NMIBC. Of all 126 patients, 94 patients with high-risk NMIBC were selected and divided into 2 groups using a pseudo randomization with propensity score matching to minimize systematic differences in the process of forming groups. The treatment group (n = 55) consisted of patients with high-risk NMIBC who received a 6-week course of adjuvant IVCT with TGA. In the control group (n = 39) patients received an induction 6-week course of adjuvant intravesical BCG therapy, 19 (49 %) of 39 patients received maintenance therapy. Both methods were compared according to recurrence rate, progression rate and recurrence-free survival. Significance of difference was set at p <0.05.Results. The compared groups of patients were well balanced in terms of clinical and morphological characteristics and the main risk factors for recurrence and progression of non-muscle-invasive bladder cancer, no significant differences were found between the groups (p >0.5). The recurrence rate in treatment and control groups was 33 % and 23 %, respectively (p = 0.31). The disease progression was observed in 1 (2 %) patient in the treatment group and in 4 (13 %) patients in the control group (p = 0.08). The median disease-free survival in both groups of patients was not reached at the time of analysis. Three- and five-year recurrence-free survival in the treatment group of patients were 71 % and 62 %, respectively; in the control group — 76 % and 72 %, respectively. There were no significant differences between recurrence-free-survival curves of the treatment and control groups (p = 0.58).Conclusion. Adjuvant IVCT with TGA has demonstrated a clinical effectiveness comparable to intravesical BCG therapy and it can be used as an alternative method of treatment in patients with high-risk NMIBC.Цель исследования — сравнить безрецидивную выживаемость, частоту рецидивов и прогрессирования заболевания у больных немышечно-инвазивным раком мочевого пузыря (НМИРМП) высокого риска после адъювантной внутрипузырной химиотерапии (ВПХТ) с аквакомплексом глицеросольвата титана (АГТ) в сравнении с внутрипузырной терапией бациллой Кальметта-Герена (БЦЖ).Материалы и методы. В ретроспективное мультицентровое сравнительное клиническое исследование исходно включены 126 пациентов с НМИРМП. Из них с использованием метода псевдорандомизации (propensity score matching) отобраны 94 пациента с НМИРМП высокого риска, которые были разделены на 2 группы: основную и контрольную. Основную группу (n = 55) составили больные, получившие 6-недельный курс адъювантной ВПХТ с АГТ. Пациенты контрольной группы (n = 39) получили индукционный 6-недельный курс адъювантной внутрипузырной БЦЖ-терапии в режиме 1 инстилляция в неделю, у 19 (49 %) из 39 больных проводилось поддерживающее лечение в срок от 2 до 16 мес. Сравнение эффективности различных методик адъювантной внутрипузырной терапии выполняли по показателям безрецидивной выживаемости, частоте рецидивов и прогрессирования заболевания. Достоверность различий устанавливали при уровне значимости p <0,05.Результаты. Сравниваемые группы больных были хорошо сбалансированы по клинико-морфологическим характеристикам и основным факторам риска рецидива и прогрессирования НМИРМП, достоверных различий между ними не выявлено (p >0,5). Частота рецидивов заболевания в основной и контрольной группах составила 33 и 23 % соответственно (р = 0,31). Прогрессирование заболевания установлено у 1 (2 %) больного в основной группе и у 4 (13 %) больных в контрольной группе (p = 0,08). Медиана безрецидивной выживаемости в обеих группах на момент проведения анализа не достигнута. Показатели 3- и 5-летней безрецидивной выживаемости в основной группе составили 71 и 62 %, в контрольной группе - 76 и 72 % соответственно. При сравнении кривых безрецидивной выживаемости основной и контрольной групп достоверных различий между ними не выявлено (p = 0,58).Заключение. Адъювантная ВПХТ с АГТ позволяет получить сопоставимые с внутрипузырной БЦЖ-терапией основные показатели эффективности и может применяться в качестве альтернативного метода лечения у больных НМИРМП высокого риска

Writing Russia's future: paradigms, drivers, and scenarios

The development of prediction and forecasting in the social sciences over the past century and more is closely linked with developments in Russia. The Soviet collapse undermined confidence in predictive capabilities, and scenario planning emerged as the dominant future-oriented methodology in area studies, including the study of Russia. Scenarists anticipate multiple futures rather than predicting one. The approach is too rarely critiqued. Building on an account of Russia-related forecasting in the twentieth century, analysis of two decades of scenarios reveals uniform accounts which downplay the insights of experts and of social science theory alike