Three-dimensional modeling of lightning-induced electromagnetic pulses on Venus, Jupiter and Saturn

While lightning activity in Venus is still controversial, its existence in Jupiter and Saturn was first detected by the Voyager missions and later on confirmed by Cassini and New Horizons optical recordings in the case of Jupiter, and recently by Cassini on Saturn in 2009. Based on a recently developed 3D model we investigate the influence of lightning-emitted electromagnetic pulses (EMP) on the upper atmosphere of Venus, Saturn and Jupiter. We explore how different lightning properties such as total energy released and orientation (vertical, horizontal, oblique) can produce mesospheric transient optical emissions of different shapes, sizes and intensities. Moreover, we show that the relatively strong background magnetic field of Saturn can enhance the lightning-induced quasi-electrostatic and inductive electric field components above 1000 km of altitude producing stronger transient optical emissions that could be detected from orbital probes

Uniqueness of a solution of a steady state photochemical problem: Applications to Mars

Based on the conservation of chemical elements in chemical reactions, a rule is proved that the number of boundary conditions given by densities and/or non-zero velocities should not be less than the number of chemical elements in the system, and the components given by densities and velocities should include all elements in the system. Applications of this rule to Mars are considered. It is proved that a problem of CO2-H2O chemistry in the lower and middle atmosphere of Mars, say, in the range of 0-80 km does not have an unique solution, if only CO2 and H2O densities are given at the lower boundary, while all other boundary conditions are fluxes. Two models of this type are discussed. These models fit the same boundary conditions, are balanced with a relative uncertainty of 10(exp -4) for H2, and predict the O2, CO, and H2 mixing ratios which differ by order of magnitude. One more species density, e.g. that of O2, should be specified at the boundary to obtain the unique solution. The situation is better if the upper boundary is extended to the exobase where thermal escape velocities of H and H2 can be specified. However, in this case, either oxygen nonthermal escape rate or the O2 density at the surface should be given as the boundary condition. Two models of Mars' photochemistry, with and without nitrogen chemistry, are considered. The oxygen nonthermal escape rate of 1.2 x 10(exp 8) cm(exp -2) s(exp -1) is given at 240 km and is balanced with the total hydrogen escape rate within uncertainty of 1 percent for both models. Both models fit the measured O2 and CO mixing ratios, the O3 line absorption at 9.6 microns, and the O2 1.27 microns dayglow within the uncertainties of the measured values; although, the model without nitrogen chemistry fits better

Дослідження параметрів ліофілізації при одержанні ліпосомальної форми іринотекану

The creation of the liposomal irinotecan is one of the main ways to reduce toxicity and increase the effectiveness of chemotherapy. Lyophilization makes it possible to obtain a product with a guaranteed stability of the size and encapsulation efficiency.Aim. To optimize the content of the cryoprotector in the liposomal irinotecan, and develop lyophilization parameters to produce liposomes with the maximum encapsulation of irinotecan in them, alongside while maintaining the nanosize.Materials and methods. Egg phosphatidylcholine from Lipoid (Germany) was used for preparation of liposomes. Lyophilization was carried out in a Quarco device (PR China). The encapsulation degree was determined on a Shimadzu LC-20 instrument (Japan) by HPLC method developed earlier.Results and discussion. The optimal content of the cryoprotector – trehalose dihydrate has been studied. It has been found that the optimal content of trehalose dihydrate is 8 % (w/w). The modes of the product lyophilization have been studied. The secondary drying temperature in the range of 10-20 °C has been determined. At the secondary drying temperature of 10 °C the residual moisture content was 5-8 %, which was beyond the target range. At 20 °C the water content in the lyophilizate was 0.5-0.8 %, the loss of encapsulation was up to 20 %. The mode of drying at 15 °C was optimal, while the residual water content in the lyophilizate was 1.5-2.8 %, the loss of encapsulation was 13 %, the size of the liposomes after lyophilization and rehydration did not change significantly compared to the initial one.Conclusions. As a result of the studies, liposomes with irinotecan have been obtained. The content of trehalose dihydrate as a cryoprotector in the range of 4-10 % has been studied. It has been shown that the optimum content of trehalose dihydrate is 8 % (w/w); moreover, the encapsulation decrease in lyophilization is 13 %. The modes of the liposomal irinotecan lyophilization have been studied at the final drying temperature of 10, 15 and 20 °C. It has been found that the optimum final drying temperature is 15 °C.Создание липосомальной формы иринотекана – один из основных путей уменьшения токсичности и повышения эффективности при проведении химиотерапии. Лиофилизация позволяет получать продукт с гарантированным сохранением размеров и параметров инкапсуляции, поэтому исследование параметров данного процесса является актуальным.Целью исследования являются оптимизация содержания криопротектора в липосомальной форме иринотекана, разработка процесса лиофилизации для получения ЛС с максимальной инкапсуляцией в них иринотекана при сохранении наноразмеров.Материалы и методы. Для изготовления ЛС использовали яичный фосфатидилхолин фирмы Lipoid, лиофилизацию проводили в аппарате Quarco производства КНР. Определение степени инкапсуляции проводили методом ВЭЖХ на приборе Shimadzu LC-20.Результаты и их обсуждение. Проведено исследование содержания криопротектора – трегалозы дигидрата. Установлено, что оптимальным является содержание трегалозы дигидрата 8 % (масс). Проведено изучение режимов лиофилизации продукта. Изучена температура вторичного высушивания от 10 до 20 °С. При температуре вторичной сушки 10 °С содержание остаточной влаги составляло 5-8 %, что выходило за целевые рамки. При 20 °С содержание воды в лиофилизате составляло 0,5-0,8 %, потеря инкапсуляции – до 20 %. Оптимальным являлся режим при досушивании при 15 °С, при этом содержание остаточной воды в лиофилизате составило 1,5-2,8 %, потеря инкапсуляции составила 13 %, размер липосом после лиофилизации и регидратации существенно не изменялся в сравнении с исходным.Выводы. В результате проведенных исследований получены лекарственные средства с иринотеканом. Исследовано содержание трегалозы дигидрата в качестве криопротектора в диапазоне от 4 до 10 %. Показано, что оптимальным является содержание трегалозы дигидрата 8 % (мас), при этом снижение инкапсуляции при лиофилизации составляет 13 %. Исследованы режимы лиофилизации ЛС с иринотеканом при температуре досушивания 10, 15, 20 °С. Установлено, что оптимальной является температура досушивания 15 °С.Створення ліпосомальной форми іринотекану – один з основних шляхів зменшення токсичності і підвищення ефективності при проведенні хіміотерапії. Ліофілізація дозволяє отримувати продукт з гарантованим збереженням розмірів і параметрів інкапсуляції, тому дослідження параметрів даного процесу є актуальним. Метою дослідження є оптимізація вмісту кріопротектора в ліпосомальній формі іринотекану, розробка процесу ліофілізаціі для отримання ЛЗ з максимальною інкапсуляцією в них іринотекану при збереженні нанорозмірів. Матеріали та методи. Для виготовлення лікарського засобу використовували яєчний фосфатидилхолін фірми Lipoid, ліофілізацію проводили в апараті Quarco виробництва КНР. Визначення ступеня інкапсуляції проводили методом ВЕРХ на приладі Shimadzu LC-20.Результати та їх обговорення. Проведено дослідження вмісту кріопротектора – трегалози дигідрату. Встановлено, що оптимальним є вміст трегалози дигідрату 8 % (мас). Проведено вивчення режимів ліофілізації продукту. Вивчено температуру вторинного висушування від 10 до 20 °С. При температурі вторинного висушування 10 °С вміст залишкової вологи становив 5-8 %, що виходило за цільові рамки. При 20 °С вміст води в ліофілізаті становив 0,5- 0,8 %, втрата інкапсуляції – до 20 %. Оптимальним був режим при досушуванні при 15 °С, при цьому вміст залишкової води в ліофілізаті склав 1,5-2,8 %, втрата інкапсуляції склала 13 %, розмір ліпосом після ліофілізації та регідратації істотно не змінювався в порівнянні з вихідним значенням.Висновки. В результаті проведених досліджень отримані лікарські засоби з іринотеканом. Досліджено вміст трегалози дигідрату як кріопротектора в діапазоні від 4 до 10 %. Показано, що оптимальним є вміст трегалози дигідрату 8 % (мас), при цьому зниження інкапсуляції при ліофілізації становить 13 %. Досліджені режими ліофілізації лікарських засобів з іринотеканом при температурі досушування 10, 15, 20 °С. Встановлено, що оптимальною є температура досушування 15 °С

A Search for EUV Emission from Comets with the Cosmic Hot Interstellar Plasma Spectrometer (CHIPS)

We have obtained EUV spectra between 90 and 255 \AA of the cometsC/2002 T7 (LINEAR), C/2001 Q4 (NEAT), and C/2004 Q2 (Machholz) near their perihelion passages in 2004 with the Cosmic Hot Interstellar Plasma Spectrometer (CHIPS). We obtained contemporaneous data on Comet NEAT Q4 with the $Chandra$ X-ray Observatory ACIS instrument, marking the first simultaneous EUV and X-ray spectral observations of a comet. The total CHIPS/EUV observing times were 337 ks for Q4, 234 ks for T7, and 483 ks for Machholz and for both CHIPS and $Chandra$ we calculate we have captured all the comet flux in the instrument field of view. We set upper limits on solar wind charge exchange emission lines of O, C, N, Ne and Fe occurring in the spectral bandpass of CHIPS. The spectrum of Q4 obtained with $Chandra$ can be reproduced by modeling emission lines of C, N O, Mg, Fe, Si, S, and Ne solar wind ions. The measured X-ray emission line intensities are consistent with our predictions from a solar wind charge exchange model. The model predictions for the EUV emission line intensities are determined from the intensity ratios of the cascading X-ray and EUV photons arising in the charge exchange processes. They are compatible with the measured limits on the intensities of the EUV lines. For comet Q4, we measured a total X-ray flux of 3.7$\times 10^{-12}$ ergs cm$^{-2}$ s$^{-1}$, and derive from model predictions a total EUV flux of 1.5$\times 10^{-12}$ erg cm$^{-2}$ s$^{-1}$. The CHIPS observations occurred predominantly while the satellite was on the dayside of Earth. For much of the observing time, CHIPS performed observations at smaller solar angles than it was designed for and EUV emission from the Sun scattered into the instrument limited the sensitivity of the EUV measurements.Comment: 28 pages total, 4 tables, 7 figures. Accepted by The Astrophysical Journa

Magnetic collimation of the relativistic jet in M87

We apply a two-zone MHD model to the jet of M87. The model consists of an inner relativistic outflow, which is surrounded by a non-relativistic outer disk-wind. The outer disk-wind collimates very well through magnetic self-collimation and confines the inner relativistic jet into a narrow region around the rotation axis. Further, we show by example, that such models reproduce very accurately the observed opening angle of the M87 jet over a large range from the kiloparsec scale down to the sub-parsec scale.Comment: 4 pages, 2 figures, accepted by A&A Letter

On the structure and stability of magnetic tower jets

Modern theoretical models of astrophysical jets combine accretion, rotation, and magnetic fields to launch and collimate supersonic flows from a central source. Near the source, magnetic field strengths must be large enough to collimate the jet requiring that the Poynting flux exceeds the kinetic-energy flux. The extent to which the Poynting flux dominates kinetic energy flux at large distances from the engine distinguishes two classes of models. In magneto-centrifugal launch (MCL) models, magnetic fields dominate only at scales $\lesssim 100$ engine radii, after which the jets become hydrodynamically dominated (HD). By contrast, in Poynting flux dominated (PFD) magnetic tower models, the field dominates even out to much larger scales. To compare the large distance propagation differences of these two paradigms, we perform 3-D ideal MHD AMR simulations of both HD and PFD stellar jets formed via the same energy flux. We also compare how thermal energy losses and rotation of the jet base affects the stability in these jets. For the conditions described, we show that PFD and HD exhibit observationally distinguishable features: PFD jets are lighter, slower, and less stable than HD jets. Unlike HD jets, PFD jets develop current-driven instabilities that are exacerbated as cooling and rotation increase, resulting in jets that are clumpier than those in the HD limit. Our PFD jet simulations also resemble the magnetic towers that have been recently created in laboratory astrophysical jet experiments.Comment: 16 pages, 11 figures, published in ApJ: ApJ, 757, 6

ТЕХНОЛОГІЧНІ ПАРАМЕТРИ ВИРОБНИЦТВА ЛІПОСОМ З ОКСАЛІПЛАТИНОМ

The development of medicines of a nanoscale diapason opens a new trend in the modern pharmaceutical industry. Reducing the toxicity of known cytotoxic agents is one of the advantages of the liposomal biotechnology platform. The aim of the work is to offer scientifically grounded technology of production of liposomal form of oxaliplatin based on the experiment. To analyze intermediate products, define control points.Materials and Methods. Egg phosphatidylcholine produced byLipoid,Germany was used to make liposomes. Dipalmitoylphosphatidylglycerin, cholesterol, solvents used by the companySigma-Aldrich,USA. The lipid film was obtained on a rotary evaporator Buchi 210. For homogenization, an extrusion method at high pressure was used. The lyophilization process was carried out on Quarco equipment (PRC).Results and Discussion. The experimental industrial technology of obtaining the liposomal form of oxaliplatin was developed. The development of a full-fledged technology requires the study of colloidal properties of a heterogeneous nano-system, especially at the rehydration stage, lyophilization parameters, validation of control methods for the encapsulation of oxaliplatin into liposomes, validation of quantitative determination and determination of impurities.Conclusions. A new, original technology and control points for obtaining liposomal form of oxaliplatin are proposed. The technology has been tested on batches of preparations, used for preclinical studies.Мета роботи: на основі експерименту запропонувати науково-обґрунтовану технологію виробництва ліпосомальної форми оксаліплатину. Провести аналіз проміжних продуктів, визначити контрольні точки.Матеріали і методи. Для виготовлення ліпосом використовували яєчний фосфатидилхолін виробництва Lipoid (Німеччина). Дипальмітоілфосфатидилгліцерин, холестерин і розчинники використовували виробництва фірми Sigma-Aldrich (США). Ліпідну плівку отримували на роторному випарювачі Buchi 210. Для гомогенізації використовували метод екструзії при високому тиску. Процес ліофілізації здійснювали на обладнанні Quarco (КНР).Результати й обговорення.  Розроблено дослідно-промислову технологію отримання ліпосомальної форми оксаліплатину. Створення повноцінної технології вимагало вивчення колоїдних властивостей гетерогенної лікарської наносистеми, особливо на етапі регідратації, параметрів ліофілізації, валідації методик контролю ступеня інкапсуляції оксаліплатину в ліпосоми, валідації кількісного визначення і визначення сторонніх домішок.Висновки. Запропоновано нову, оригінальну технологію отримання ліпосомальної форми оксаліплатину. Технологію апробовано на серіях препарату для проведення доклінічних досліджень

Non-thermal escape of molecular hydrogen from Mars

We present a detailed theoretical analysis of a non-thermal escape of molecular hydrogen from Mars induced by collisions with hot atomic oxygen from martian corona. To accurately describe the energy transfer in O + H$_2(v,j)$ collisions, we performed extensive quantum-mechanical calculations of state-to-state elastic, inelastic, and reactive cross sections. The escape flux of H$_2$ molecules was evaluated using a simplified 1D column model of the martian atmosphere with realistic densities of atmospheric gases and hot oxygen production rates for the low solar activity conditions. An average density of the non-thermal escape flux of H$_2$ of $1.9\times10^5$ cm$^{-2}$s$^{-1}$ was obtained considering energetic O atoms produced in dissociative recombinations of O$_{2}^{+}$ ions. Predicted rovibrational distribution of the escaping H$_2$ was found to contain a significant fraction of higher rotational states. While the non-thermal escape rate was found to be lower than Jeans flux for H$_2$ molecules, the non-thermal escape rates of HD and D$_2$ are significantly higher than their respective Jeans rates. The accurate values of non-thermal escape fluxes of different molecular isotopes of H$_2$ may be important in analyses of evolution of the martian atmosphere. The described molecular ejection mechanism is general and expected to contribute to atmospheric escape of H$_2$ and other light molecules from planets, satellites, and exoplanetary bodies.Comment: submitted to Geophys. Res. Let

Applying machine learning to improve simulations of a chaotic dynamical system using empirical error correction

Dynamical weather and climate prediction models underpin many studies of the Earth system and hold the promise of being able to make robust projections of future climate change based on physical laws. However, simulations from these models still show many differences compared with observations. Machine learning has been applied to solve certain prediction problems with great success, and recently it's been proposed that this could replace the role of physically-derived dynamical weather and climate models to give better quality simulations. Here, instead, a framework using machine learning together with physically-derived models is tested, in which it is learnt how to correct the errors of the latter from timestep to timestep. This maintains the physical understanding built into the models, whilst allowing performance improvements, and also requires much simpler algorithms and less training data. This is tested in the context of simulating the chaotic Lorenz '96 system, and it is shown that the approach yields models that are stable and that give both improved skill in initialised predictions and better long-term climate statistics. Improvements in long-term statistics are smaller than for single time-step tendencies, however, indicating that it would be valuable to develop methods that target improvements on longer time scales. Future strategies for the development of this approach and possible applications to making progress on important scientific problems are discussed.Comment: 26p, 7 figures To be published in Journal of Advances in Modeling Earth System

Structural trace of adaptation in motive nuclei of spinal cord of rats in hypokinesia and after physical loading in the recovery period

The purpose of this paper is to study the morphological changes of neurocytes in spinal cord of rats in hypokinesia and subsequent physical loading. Studies were performed on 55 laboratory rats of Wistar line. Materials of the research were the anterior horns of the gray matter of L5-S2 spinal segments. Preparations stained by Nissl and Viktorov were examined histologically. Hypokinesia was modeled following on the author’s technique. It was established that during prolonged hypokinesia in neurocytes of spinal cord of rats morphological changes in cell size and shape of the motor nuclei of all segments under study have been recorded. The number of hypochromic, hyperchromic destructively unchanged and hyperchromic destructively altered neurocytes increase; shadow cells appears, as well as cases of satellitosis and neuronophagia. Decrease in of albumen synthetical neurocyte function has been recorded. Physical loading of the average aerobic capacity leads to normalization of structural and functional state of neurocytes and enhances the reparative processes, as evidenced by a number of positive changes in morphometric parameters: increase in the number of normochromic neurocytes and decreasing the number of hyper- and hypochromic neurocytes with destructive signs, absence of pyknotic forms. Morphological parameters of neurocytes and their nuclei after physical loading of average aerobic capacity do not differ from those in the control group of intact animals. In neurocytes of this group of rats RNA concentration increases by 12.6% compared to animals after prolonged hypokinesia. Neurocytes of spinal cord of rats after prolonged hypokinesia develop significant morphological changes which are characterized by emergence of a significant number of hyperchromic neurocytes with signs of destructive changes and shadow cells, as well as and hypochromic neurocytes with signs of destructive changes, reduction in size and change of shape of perikaryons of neurocytes and their nuclei. Morphological changes of neurocytes after prolonged hypokinesia are accompanied by violations of biosynthetic processes, as evidenced by RNA decrease in the cytoplasm of efferent neurocytes of spinal cord of rats. Physical loading of average aerobic capacity leads to normalization of structural and functional state of neurocytes and promotes the reparative processes suported by positive changes in morphometric parameters