Renormalized theory of the ion cyclotron turbulence in magnetic field--aligned plasma shear flow

The analytical treatment of nonlinear evolution of the shear-flow-modified current driven ion cyclotron instability and shear-flow-driven ion cyclotron kinetic instabilities of magnetic field--aligned plasma shear flow is presented. Analysis is performed on the base of the nonlinear dispersion equation, which accounts for a new combined effect of plasma turbulence and shear flow. It consists in turbulent scattering of ions across the shear flow with their convection by shear flow and results in enhanced nonlinear broadening of ion cyclotron resonances. This effect is found to lead to the saturation of ion cyclotron instabilities as well as to the development of nonlinear shear flow driven ion cyclotron instability. 52.35.RaComment: 21 page

Bioenergetic status and hypoxia in Lewis lung carcinoma assessed by 31P NMR spectroscopy: correlation with tumor progression

Aim: Тo evaluate the hypoxia level and some indices of Lewis lung carcinoma energy metabolism by means of 31Р NMR spectroscopy in perchloric acid (PCA) tissue extracts during growth of primary tumor and metastasis. Мaterials and Methods: C57Bl/6 mice-bearing Lewis lung carcinoma were used in this study. Tumor energy metabolism was studied by 31P NMR spectroscopy and the metabolic NMR ratios were used as parameters for metabolic status and hypoxia level. Results: It was shown that growth of primary tumor is accompanied with increase of Pi/PCr, Pi/bNТP and PME/bNТP ratios that reflect drop of tumor energy status and oxygenation level in tumor tissue. These changes in relevant metabolic ratios correlate with enlargement of primary tumor volume (r = 0.87, p = 0.0045; r = 0.90, p = 0.0012; r = 0.764, p = 0.05, respectively) as well as with the number of lung metastases (rs = 0.761, p = 0.028; rs = 0.86, p = 0.0049; rs = 0.77, p = 0.040, respectively). Conclusion: In present study it was shown that 31Р NMR spectroscopy of PCA tumor tissue extracts may be used as reliable method for the assessment of the level of oxygenation as well as changes in energy metabolism in the experimental tumors. It may be helpful to evaluate the energy status of human tumors by investigation both of biopsy and surgical specimens. Hypoxia and hypoxia-associated metabolic events in primary tumor are linked with malignant progression, in particular metastasis.Цель: определить уровень гипоксии и некоторые показатели энергетического метаболизма карциномы легкого Льюис с помощью 31Р ЯМР-спектроскопии перхлорных (РСА) экстрактов ткани в процессе роста первичной опухоли и ее метастазировании. Мaтериалы и методы: использовали в исследовании мышей C57Bl/6 с перевивной карциномой легкого Льюис. Энергетический метаболизм опухоли изучали с помощью ЯМР спектроскопии, oтношения фосфорсодержащих метаболитов использовали в качестве параметров метаболического статуса и уровня гипоксии. Результаты: установлено, что рост первичной опухоли сопровождается увеличением соотношений Pi/PCr, Pi/βNТP and PME/βNТP в опухоли, что отражает снижение уровня биоэнергетического статуса и уровня оксигенации в опухоли. Эти изменения соотношений важных метаболических показателей коррелируют с увеличением объема первичной опухоли (r = 0,87, p = 0,0045; r = 0,90, p = 0,0012; r = 0,764, p = 0,05 соответственно) и количеством метатазов в легких (rs = 0,761, p = 0,028; rs = 0,86, p = 0,0049; rs = 0,77, p = 0,040 соответственно). Выводы: установлено, что 31Р ЯМР-спектроскопия PCA тканевых экстрактов может быть надежным методом оценки уровня оксигенации и биоэнергетического статуса экспериментальных опухолей. Этот метод может быть полезным при оценке энергетического метаболизма опухолей человека, в частности при исследовании биопсийного и операционного материала. Гипоксия и гипоксия-ассоциированные изменения метаболизма в первичной опухоли связаны со злокачественной прогрессией, в частности с метастазированием

Water Vapor Absorption in the Region of the Oxygen A-Band Near 760 nm

The oxygen A-band near 760 nm is used to determine the air-mass along the line of sight from ground or space borne atmospheric spectra. This band is located in a spectral region of very weak absorption of water vapor. The increased requirements on the determination of the air columns make suitable to accurately characterize water absorption spectrum in the region. In the present work, we use a cavity ring down spectrometer newly developed in Tomsk, to measure with unprecedented sensitivity and accuracy the water spectrum in the 12969 - 13172 cm−1 region. While about fifty transitions were previously detected in the region, a total of about 580 water lines are measured by CRDS and rovibrationally assigned, leading to the determination of 103 new levels and correction of 134 levels of H216O. Spectroscopic line lists available in the region (HITRAN, W2020 and theoretical line lists) show some important deviations compared to observations. In particular, line intensities are poorly predicted by available ab initio calculations for transitions involving a highly bending excitation. © 2021 Elsevier Ltd.The support of the CNRS (France) in the frame of International Research Project SAMIA is acknowledged. CRDS measurements and spectrum analysis were performed at IAO-Tomsk and funded by RFBR project 20-32-70054

Mechanochemistry and solubilization of drugs

The results on solubilization of poorly water-soluble drugs, indomethacin, piroxicam, and meloxicam, with the help of mechanochemical methods are presented. The mechanocomposites of the drugs with various excipients, including soluble polymers and non-soluble fine porous inorganic oxides, were obtained by co-grinding using vibrational and planetary centrifugal mills. The samples obtained revealed higher release rate and apparent solubility of the drugs with respect to the initial ones. Nevertheless, in some cases, e.g. for composites of piroxicam with alumina and ferric oxide, decreasing the release rate and solubility of the drug was observed suggesting the formation of poorly soluble strong drug - carrier associates

Analysis of spatial humus distribution in virgin and arable Chernozems in the eroding landscapes

A statistical assessment of data on the content and spatial distribution of humus in virgin and arable Chernozems on slopes in the south of the forest-steppe zone of the Central Russian Upland was performed. The greatest number of statistically significant differences between arable and virgin Chernozems was found for the upper soil layer (0–20 cm

Радіометричний модуляційний вимірювач інтенсивності оптичного випромінювання

Introduction. The paper proposed a block diagram of radiometric measuring the intensity of optical radiation from modulation conversion parameter input . To assess the intensity of use periodically comparing the reference signal (shaded) and measurement (open) photodi-odes. Studies. The proposed radiometric modulation meter provides increased sensitivity and measurement accuracy by reducing the influence of dark current measurement and reference photodiodes and compensation intrinsic noise measuring channel through their periodic anti-phase comparison.В статье предложена структурная схема радиометрического измерителя интенсивности оптического излучения на основе модуляционного преобразования параметра входного сигнала. Для оценки интенсивности используется периодическое сравнения сигналов опорного (затемнен-ного) и измерительного (открытого) фотодиодов. Предложенный радиометрический модуляционный измеритель обеспечивает повышение чувствительности и точности измерения за счет уменьшения влияния темнового тока измерительного и опорного фотодиодов и компенсации собственных шумов измерительного канала путем их периодического противофазное сравнения.В статті запропонована структурна схема радіометричного вимірювача інтенсивності оптичного випромінювання на основі модуляційного перетворення параметра вхідного сигналу. Для оцінки інтенсивності використовується періодичне порівняння сигналів опорного (затемненого) та вимірювального (відкритого) фотодіодів. Запропонований радіометричний модуляційний вимірювач забезпечує підвищення чутливості та точності вимірювання за рахунок зменшення впливу темнового струму вимірювального і опорного фотодіодів та компенсаціі власних шумів вимірювального каналу шляхом їх періодичного протифазного порівняння

Validation Tests of the W2020 Energy Levels of Water Vapor

A decade ago, a task group of the International Union of Pure and Applied Chemistry performed an exhaustive collection and review of measured transitions, applied the MARVEL procedure, and derived recommended empirical energy levels for nine major water isotopologues. Very recently, using an improved methodology, the sets of empirical energy levels of H216O, H218O and H217O were updated, leading to the so-called W2020 energy levels and transition wavenumbers [Furtenbacher et al. J. Phys. Chem. Ref. Data 49 (2020) 043103; 10.1063/5.0030680]. Here we present validation tests of the W2020 line list of H216O against spectra recorded by cavity ring down spectroscopy (CRDS) referenced to a frequency comb (FC), newly obtained in the 8040-8630 cm−1 region. The recorded spectra are found in excellent agreement with previous high-quality studies available in the literature. While these literature sources were all incorporated in the transition database used to derive the W2020 energy levels, the direct superposition of the FC-CRDS spectra to the W2020 line list of H216O shows a number of large disagreements. Cases where deviations largely exceed the W2020 claimed uncertainty on the transition frequencies are noted. In the considered spectral region, the resulting W2020 list is thus less accurate than some of the published original sources used to derive the W2020 energy levels. We conclude that the sophisticated global procedure and algorithm elaborated to identify and adequately weight inaccurate line positions among the large W2020 transition database do not always prevent less accurate data from “spoiling” higher quality data sources. The W2020 list of H216O is also compared to newly recorded CRDS spectra in the 12970–13200 cm−1 region (corresponding to the region of the A-band of O2), where previous observations were very scarce. As in the previous region, substantial position deviations are evidenced, and in many cases, the W2020 error bars appear to be strongly underestimated. © 2021 Elsevier LtdThe support of the CNRS (France) in the frame of International Research Project SAMIA is acknowledged. SNM activity was also partly supported in the frame of the Russian Science Foundation, Grant No. 18-11-00024-Π. CRDS measurements near 760 nm were performed at IAO-Tomsk and funded by RFBR project 20-32-70054

High Resolution Infrared Spectroscopy in Support of Ozone Atmospheric Monitoring and Validation of the Potential Energy Function

The first part of this review is a brief reminder of general information concerning atmospheric ozone, particularly related to its formation, destruction, observations of its decrease in the stratosphere, and its increase in the troposphere as a result of anthropogenic actions and solutions. A few words are said about the abandonment of the Airbus project Alliance, which was expected to be the substitute of the supersonic Concorde. This project is over due to the theoretical evaluation of the impact of a fleet in the stratosphere and has been replaced by the A380, which is now operating. The largest part is devoted to calculations and observations of the transitions in the infrared range and their applications for the atmosphere based both on effective models (Hamiltonian, symmetry rules, and dipole moments) and ab initio calculations. The complementarities of the two approaches are clearly demonstrated, particularly for the creation of an exhaustive line list consisting of more than 300,000 lines reaching experimental accuracies (from 0.00004 to 0.001 cm−1) for positions and a sub percent for the intensities in the 10 microns region. This contributes to definitively resolving the issue of the observed discrepancies between line intensity data in different spectral regions: between the infrared and ultraviolet ranges, on the one hand, and between 10 and 5 microns on the other hand. The following section is devoted to the application of recent work to improve the knowledge about the behavior of potential function at high energies. A controversial issue related to the shape of the potential function in the transition state range near the dissociation is discussed. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Funding: The activities of S.M. and E.S. were supported by the Ministry of Science and Higher Education of the Russian Federation (V.E. Zuev Institute of Atmospheric Optics SB RAS); the work of S.M. was also supported by Ural Federal University

New transitions and energy levels of water vapor by high sensitivity CRDS near 1.73 and 1.54 µm

This contribution is part of a long term project aiming at improving the water absorption spectroscopy by high sensitivity cavity ring down spectroscopy (CRDS) in the near infrared. Two new sources of CRDS spectra are considered: (i) The room temperature absorption spectrum of water vapor in natural isotopic abundance is recorded near 1.73 µm. A series of recordings was performed from 5693 to 5991 cm−1 with a pressure value of about 6 Torr. The noise equivalent absorption (αmin) of the spectra is better than 10− 10 cm−1. A total of 1453 lines were assigned to 1573 transitions of four water isotopologues (H2 16O, H2 17O, H2 18O and HD16O). Their intensities span more than five orders of magnitude from 3.0 × 10−30 to 4.7 × 10−25 cm/molecule at 296 K. The assignments were performed using known experimental energy levels as well as calculated line lists based on the results of Schwenke and Partridge. Two hundred fifty-one lines (assigned to 280 transitions) are observed for the first time and twelve energy levels are newly determined. The comparison of the obtained line parameters with those of the HITRAN database is discussed. Forty-six line positions are observed to significantly differ from their HITRAN values (δν = │νHITRAN – νCRDS│ > 0.02 cm−1). The derived set of energy levels is compared to those recommended by an IUPAC task group. (ii) The room temperature CRDS spectrum of water vapor highly enriched in 17O was recorded near 1.54 µm (6223–6672 cm−1) at a pressure of 12 Torr. Compared to a previous study, the higher pressure of the recordings allowed for extending the observations. Overall, twenty-six new levels were determined for both H2 17O and HD17O. All these observations together with other recent measurements will allow for an extension and an update of our empirical database in the 5693– 8340 cm−1 region. © 2019 Elsevier Lt

Swirling astrophysical flows - efficient amplifiers of Alfven waves

We show that a helical shear flow of a magnetized plasma may serve as an efficient amplifier of Alfven waves. We find that even when the flow is purely ejectional (i.e., when no rotation is present) Alfven waves are amplified through the transient, shear-induced, algebraic amplification process. Series of transient amplifications, taking place sequentially along the flow, may result in a cascade amplification of these waves. However, when a flow is swirling or helical (i.e., some rotation is imposed on the plasma motion), Alfven waves become subject to new, much more powerful shear instabilities. In this case, depending on the type of differential rotation, both usual and parametric instabilities may appear. We claim that these phenomena may lead to the generation of large amplitude Alfven waves and the mechanism may account for the appearance of such waves in the solar atmosphere, in accretion-ejecion flows and in accretion columns. These processes may also serve as an important initial (linear and nonmodal) phase in the ultimate subcritical transition to MHD Alfvenic turbulence in various kinds of astrophysical shear flows.Comment: 12 pages, 11 figures, accepted for publication (25-11-02) in Astronomy and Astrophysic