Communication: XUV transient absorption spectroscopy of iodomethane and iodobenzene photodissociation

Time-resolved extreme ultraviolet (XUV) transient absorption spectroscopy of iodomethane and iodobenzene photodissociation at the iodine pre-N4,5 edge is presented, using femtosecond UV pump pulses and XUV probe pulses from high harmonic generation. For both molecules the molecular core-to-valence absorption lines fade immediately, within the pump-probe time-resolution. Absorption lines converging to the atomic iodine product emerge promptly in CH3I but are time-delayed in C6H5I. We attribute this delay to the initial π → σ* excitation in iodobenzene, which is distant from the iodine reporter atom. We measure a continuous shift in energy of the emerging atomic absorption lines in CH3I, attributed to relaxation of the excited valence shell. An independent particle model is used to rationalize the observed experimental findings

DruGAN: An Advanced Generative Adversarial Autoencoder Model for de Novo Generation of New Molecules with Desired Molecular Properties in Silico

© 2017 American Chemical Society. Deep generative adversarial networks (GANs) are the emerging technology in drug discovery and biomarker development. In our recent work, we demonstrated a proof-of-concept of implementing deep generative adversarial autoencoder (AAE) to identify new molecular fingerprints with predefined anticancer properties. Another popular generative model is the variational autoencoder (VAE), which is based on deep neural architectures. In this work, we developed an advanced AAE model for molecular feature extraction problems, and demonstrated its advantages compared to VAE in terms of (a) adjustability in generating molecular fingerprints; (b) capacity of processing very large molecular data sets; and (c) efficiency in unsupervised pretraining for regression model. Our results suggest that the proposed AAE model significantly enhances the capacity and efficiency of development of the new molecules with specific anticancer properties using the deep generative models

Reaching the nonlinear regime of Raman amplification of ultrashort laser pulses

The intensity of a subpicosecond laser pulse was amplified by a factor of up to 1000 using the Raman backscatter interaction in a 2 mm long gas jet plasma. The process of Raman amplification reached the nonlinear regime, with the intensity of the amplified pulse exceeding that of the pump pulse by more than an order of magnitude. Features unique to the nonlinear regime such as gain saturation, bandwidth broadening, and pulse shortening were observed. Simulation and theory are in qualitative agreement with the measurements.open695

Спектральные характеристики поляризационно-манипулированных сигналов с непрерывным изменением параметров поляризации

Results of the analysis of the spectral characteristics of signals with polarization shift keying with continuous sequential change of the angle of orientation are given. The values of the generalized coefficient of modulation depth and width of the energy spectrum for the polarized signals with different polarization index manipulation are dealt with.В статье проведен анализ спектральных характеристик поляризационно-манипулированных сигналов с непрерывным изменением угла ориентации. Определены значения обобщенного коэффициента глубины модуляции и ширины энергетического спектра для данного вида сигналов при различных индексах поляризационной манипуляции

3D Molecular Representations Based on the Wave Transform for Convolutional Neural Networks

© 2018 American Chemical Society. Convolutional neural networks (CNN) have been successfully used to handle three-dimensional data and are a natural match for data with spatial structure such as 3D molecular structures. However, a direct 3D representation of a molecule with atoms localized at voxels is too sparse, which leads to poor performance of the CNNs. In this work, we present a novel approach where atoms are extended to fill other nearby voxels with a transformation based on the wave transform. Experimenting on 4.5 million molecules from the Zinc database, we show that our proposed representation leads to better performance of CNN-based autoencoders than either the voxel-based representation or the previously used Gaussian blur of atoms and then successfully apply the new representation to classification tasks such as MACCS fingerprint prediction

Multiorder coherent Raman scattering of a quantum probe field

We study the multiorder coherent Raman scattering of a quantum probe field in a far-off-resonance medium with a prepared coherence. Under the conditions of negligible dispersion and limited bandwidth, we derive a Bessel-function solution for the sideband field operators. We analytically and numerically calculate various quantum statistical characteristics of the sideband fields. We show that the multiorder coherent Raman process can replicate the statistical properties of a single-mode quantum probe field into a broad comb of generated Raman sidebands. We also study the mixing and modulation of photon statistical properties in the case of two-mode input. We show that the prepared Raman coherence and the medium length can be used as control parameters to switch a sideband field from one type of photon statistics to another type, or from a non-squeezed state to a squeezed state and vice versa.Comment: 12 pages, 7 figures, to be published in Phys. Rev.

Disability quotas: past or future policy?

This article considers the issues associated with the use of quota systems for the employment of workers with a disability. It examines the use and experiences of such quotas in Italy, Russia and the United Kingdom. Italy has a long established quota for the employment of such workers, whilst the modern Russian system it is a more recent innovation. In contrast the UK abandoned its quotas in the 1990s. We draw on the experiences of the three countries to consider generally whether the use of quotas is either an acceptable means of encouraging employers to take on disabled workers, or is necessary to achieve this objective

Africa’s response to the COVID-19 pandemic : A review of the nature of the virus, impacts and implications for preparedness

Background: COVID-19 continues to wreak havoc in different countries across the world, claiming thousands of lives, increasing morbidity and disrupting lifestyles. The global scientific community is in urgent need of relevant evidence, to understand the challenges and knowledge gaps, as well as the opportunities to contain the spread of the virus. Considering the unique socio-economic, demographic, political, ecological and climatic contexts in Africa, the responses which may prove to be successful in other regions may not be appropriate on the continent. This paper aims to provide insight for scientists, policy makers and international agencies to contain the virus and to mitigate its impact at all levels. Methods: The Affiliates of the African Academy of Sciences (AAS), came together to synthesize the current evidence, identify the challenges and opportunities to enhance the understanding of the disease. We assess the potential impact of this pandemic and the unique challenges of the disease on African nations. We examine the state of Africa’s preparedness and make recommendations for steps needed to win the war against this pandemic and combat potential resurgence. Results: We identified gaps and opportunities among cross-cutting issueswhich must be addressed or harnessed in this pandemic. Factors such as the nature of the virus and the opportunities for drug targeting, point of care diagnostics, health surveillance systems, food security, mental health, xenophobia and gender-based violence, shelter for the homeless, water and sanitation, telecommunications challenges, domestic regional coordination and financing. Conclusion: Based on our synthesis of the current evidence, while there are plans for preparedness in several African countries, there are significant limitations. A multi-sectoral efforts from the science, education, medical, technology, communication, business, and industry sectors, as well as local communities, must work collaboratively to assist countries in order to win this fight

РЕАКЦИЯ ЭРИТРОИДНОГО РОСТКА КРОВЕТВОРЕНИЯ НА ОПУХОЛЕВЫЙ РОСТ У БОЛЬНЫХ РАКОМ ЛЕГКОГО

Background. In addition to the transport of oxygen in tissues, erythrocytes participate in maintaining homeostasis therefore their qualitative and quantitative characterization may reflect a number of changes occurring in the body. The aim of the study was to investigate the erythrone state and reaction of red blood cells of hematopoiesis in patients with lung cancer with the assessment of ability to use such reactions as predictive signs of aggressiveness of the tumor process. Results. Clinical material indicating the presence of reaction of erythropoiesis and enzymatic antioxidant system to tumor growth in patients with lung cancer was obtained. Pathological changes in the erythrone system, including changes in the concentration of hypoxia-inducible factor 1α, quantitative and morphological characteristics of red blood cells and reticulocytes, hemoglobin concentration and the activity of superoxide dismutase correlated with tumor aggressiveness and more severe clinical status of patients. Сonclusion. A comprehensive assessment of erythropoiesis is believed can be used in selection of criteria for predicting treatment response and patients survival.Введение. Эритроциты, помимо транспорта кислорода в ткани, участвуют в поддержании гомеостаза, поэтому их качественная и количественная перестройка может отражать ряд изменений, происходящих в организме. Целью исследования явилось изучение состояния эритрона в целом и реакции красного ростка кроветворения у больных раком легкого с оценкой возможности использования таких реакций в качестве предиктивных признаков агрессивности опухолевого процесса. результаты. Получен клинический материал, свидетельствующий о наличии реакции эритроидного ростка кроветворения и ферментативного звена антиоксидантной системы на опухолевый процесс у больных раком легкого. Регистрируемые сдвиги в состоянии эритрона: концентрация гипоксией индуцированного фактора 1α, количественные и морфологические характеристики эритроцитов и ретикулоцитов, концентрация гемоглобина и активность супероксиддисмутазы периферической крови коррелируют с агрессивностью опухоли и тяжестью клинического состояния больных. Заключение. Комплексная оценка состояния красного ростка кроветворения может быть использована в выборе предиктивных критериев при составлении прогноза эффективности лечения и продолжительности жизни больных.