Inverse medium problem for a singular contrast

We consider an inverse medium problem in two- and three-dimensional cases. Namely, we investigate the problem of reconstruction of unknown compactly supported refractive index (contrast) from L-2 with a fixed positive wave number. The proof is based on the new estimates for the Green-Faddeev function in L-infinity space. The main goal of this work is to prove a uniqueness result in the two- and three-dimensional cases and to discuss some possible constructive methods for solving the problem. Finally, we present some numerical examples to demonstrate the results in two dimensions. Published under license by AIP Publishing.Peer reviewe

Gas chromatography of indium in macroscopic and carrier-free amounts using quartz and gold as stationary phases

The chemical investigation of E113 is likely to become soon feasible. The determination of chemical properties of carrier-free amounts of the lighter homologues of element 113, especially indium and thallium, allows designing experimental set-ups and selecting experimental conditions suitable for performing these studies. Here, we present investigations of the interaction of indium species with quartz and gold surfaces. Deposition temperatures as well as enthalpies of adsorption were determined for indium Tdep=739±20°C (−ΔHads(In)=227±10kJ mol−1) and for indium hydroxide Tdep=250±20°C (−ΔHads(InOH)= 124±10kJ mol−1) respectively, on quartz. In case of adsorption of indium on a gold surface only a lower limit of the deposition temperature was established Tdep>980°C (−ΔHads(In)≥315±10kJ mol−1). Investigations of macroscopic amounts of indium in thermosublimation experiments at similar experimental conditions were instrumental to establish a tentative speciation of the observed indium specie

Creation of transgenic mice susceptible to coronaviruses: a platform for studying viral pathogenesis and testing vaccines

Over the past 20 years, coronaviruses have caused three epidemics: SARS-CoV, MERS-CoV, and SARS-CoV2, with the first two having a very high lethality of about 10 and 26 %, respectively. The last outbreak of coronavirus infection caused by SARS-CoV2 in 2019 in China has swept the entire planet and is still spreading. The source of these viruses in humans are animals: bats, Himalayan civets, and camels. The genomes of MERS-CoV, SARS-CoV and SARS-CoV2 are highly similar. It has been established that coronavirus infection (SARS-CoV and SARS-CoV2) occurs through the viral protein S interaction with the lung epithelium – angiotensin-converting enzyme receptor 2 (ACE2) – due to which the virus enters the cells. The most attractive model for studying the development of these diseases is a laboratory mouse, which, however, is resistant to coronavirus infection. The resistance is explained by the difference in the amino acid composition of mouse Ace2 and human ACE2 proteins. Therefore, to create mice susceptible to SARS-CoV and SARS-CoV2 coronaviruses, the human ACE2 gene is transferred into their genome. The exogenous DNA of the constructs is inserted into the recipient genome randomly and with a varying number of copies. Based on this technology, lines of transgenic mice susceptible to intranasal coronavirus infection have been created. In addition, the use of the technology of targeted genome modification using CRISPR/Cas9 made it possible to create lines of transgenic animals with the insertion of the human ACE2 gene under the control of the endogenous murine Ace2 gene promoter. This “humanization” of the Ace2 gene makes it possible to obtain animals susceptible to infection with coronaviruses. Thus, transgenic animals that simulate coronavirus infections and are potential platforms for testing vaccines have now been created

The thermal release of scandium from titanium metal - a simple way to produce pure 44Sc for PET application

The radionuclide-generator based access to radiopharmaceutical isotopes represents a valuable alternative to directly produced isotopes at particle accelerators or nuclear reactors. The 44Ti based generator is of increasing interest for the delivery of PET-radiopharmaceutical isotopes used for imaging. The product of this generator 44Sc represents with its 3.97h half-life and 94.3% positron branching[1] a very promising candidate for labeling PET radiopharmaceuticals. The long half-life of 58.9±0.3y[2] of the 44Ti assures a constant and long lasting production of the daughter nuclide. Here we present a gas phase separation method of scandium from titanium via thermal release in vacuum. Titanium foils were irradiated with 40Ar to produce scandium in multi-nucleon transfer reactions. Another production reaction used was the irradiation of titanium by neutrons from the SINQ neutron source at the Paul Scherrer Institute (PSI). The titanium metal foils containing 44mSc and 46Sc were heated up for time periods of 15 and 60min to temperatures between 900°C and 1500°C in vacuum. Thus, release properties of scandium from titanium under these conditions were studied. The released scandium was collected on tantalum foils and could be rinsed of with concentrated nitric acid resulting in carrier free scandium nitrate solutions. From the experimental results optimum release conditions are suggeste

New conditional symmetries and exact solutions of nonlinear reaction-diffusion-convection equations. II

In the first part of this paper math-ph/0612078, a complete description of Q-conditional symmetries for two classes of reaction-diffusion-convection equations with power diffusivities is derived. It was shown that all the known results for reaction-diffusion equations with power diffusivities follow as particular cases from those obtained in math-ph/0612078 but not vise versa. In the second part the symmetries obtained in are successfully applied for constructing exact solutions of the relevant equations. In the particular case, new exact solutions of nonlinear reaction-diffusion-convection (RDC) equations arising in application and their natural generalizations are found

Group classification of heat conductivity equations with a nonlinear source

We suggest a systematic procedure for classifying partial differential equations invariant with respect to low dimensional Lie algebras. This procedure is a proper synthesis of the infinitesimal Lie's method, technique of equivalence transformations and theory of classification of abstract low dimensional Lie algebras. As an application, we consider the problem of classifying heat conductivity equations in one variable with nonlinear convection and source terms. We have derived a complete classification of nonlinear equations of this type admitting nontrivial symmetry. It is shown that there are three, seven, twenty eight and twelve inequivalent classes of partial differential equations of the considered type that are invariant under the one-, two-, three- and four-dimensional Lie algebras, correspondingly. Furthermore, we prove that any partial differential equation belonging to the class under study and admitting symmetry group of the dimension higher than four is locally equivalent to a linear equation. This classification is compared to existing group classifications of nonlinear heat conductivity equations and one of the conclusions is that all of them can be obtained within the framework of our approach. Furthermore, a number of new invariant equations are constructed which have rich symmetry properties and, therefore, may be used for mathematical modeling of, say, nonlinear heat transfer processes.Comment: LaTeX, 51 page

INFLUENCE OF THERAPY UPON LPS-INDUCED CYTOKINE SECRETION BY THE BLOOD-DERIVED INNATE IMMUNITY CELLS OF THE BRONCHIAL ASTHMA PATIENTS

Bronchial asthma (BA) is the most widespread chronic inflammatory disease. Since BA is associated with a systemic inflammation state, a comprehensive study of its effect in this disease, and influence of pathogenetic therapy should be performed, by studying the whole blood cytokine status of the patients suffering with BA. The cells from respiratory tract in acute-phase BA patients may produce pro-, as well as anti-inflammatory mediators. The anti-inflammatory mediators are able to suppress activity of immune cells in peripheral blood. Thus, the aim of present study was to evaluate eventual inflammation-associated and functional activity of immune cells from the patients’ peripheral blood in BA and following appropriate therapy. Bacterial lipopolysaccharide (LPS) a classical pro-inflammatory agent. We have studied an LPSinduced cytokine-induced ex vivo secretion model by peripheral blood immune cells, as a relevant test for their functional activity. The LPS-induced responses of whole blood cells from patients with proven BA diagnosis have been studied at pre-treatment time points, and following two weeks of basic anti-inflammatory therapy. According to clinical indications, the antagonists of CysLTR1, or combinations of glucocorticosteroids and β-adrenoreceptor agonists were administered by inhalation to BA patients. LPS-induced production of TNFα, IL-6, IL-8 (at 6 h) and IFNγ, IL-17A or IL-1β (at 24 h) by whole blood cells from BA patients or healthy volunteers has been assessed by ELISA technique. The cytokine production from non-stimulated whole blood cells from BA patients and healthy volunteers were used as the baseline control. IL-4 concentrations in plasma of BA patients and healthy volunteers were also measured. We have shown a decrease of IL-6 production in control blood samples from BA patients after two weeks of therapy. This may indicate the attenuation of the observed inflammatory process. The therapy applied did not influence the background levels and LPS-induced secretion of IL-1β, IL-1ra, IFNγ, and IL-8 in whole blood samples from BA patients. IL-4 plasma levels in BA patients were not changed after two weeks of therapy. It has been shown that whole blood from BA patients produced less TNFα and IL-8, both in control samples, and during their response to LPS, than the values obtained in healthy volunteers. These findings are in agreement with a notion that BA causes partial depression of innate immune cells activity. The increased LPS-induced TNFα secretion by the whole blood cells from BA patients has been observed following two weeks of basic anti-inflammatory therapy. We suggest that the increased LPS-induced TNFα secretion could be explained by partial restoration of peripheral blood immune cell activity associated with anti-inflammatory BA therapy. To elucidate the mechanism of increased LPS-induced TNFα secretion, we have estimated whole blood concentration of soluble CD14 (sCD14) in BA patients. No significant differences between sCD14 concentrations have been found. Obtained result presume existence of sCD14-independent mechanism of TNFα regulation by whole blood cells in response on LPS which may occur during anti-inflammatory therapy of BA. We suppose that basic anti-inflammatory therapy of BA does not simply reduce IL-6 concentration in peripheral blood, but may also partially restore the activity of innate immune cells in BA patients

Time domain algorithm for accelerated determination of the first order moment of photo current fluctuations in high speed laser Doppler perfusion imaging

Advances in optical array sensor technology allow for the real time acquisition of dynamic laser speckle patterns generated by tissue perfusion, which, in principle, allows for real time laser Doppler perfusion imaging (LDPI). Exploitation of these developments is enhanced with the introduction of faster algorithms to transform photo currents into perfusion estimates using the first moment of the power spectrum. A time domain (TD) algorithm is presented for determining the first-order spectral moment. Experiments are performed to compare this algorithm with the widely used Fast Fourier Transform (FFT). This study shows that the TD-algorithm is twice as fast as the FFT-algorithm without loss of accuracy. Compared to FFT, the TD-algorithm is efficient in terms of processor time, memory usage and data transport

Capabilities of high-frequency ventilation in the intensive care unit syndrome acute lung injury and respiratory distress syndrome

In order to ascertain the possibility of high-frequency ventilation in a respiratory therapy ALII ARDS were examined 47 patients with clinical - diagnostic criteria for this syndrome, which in the course of respiratory therapy, along with ventilation, controlled by pressure, was carried out high-frequency ventilation. All patients were investigated biomechanical properties of lung, acid base status and blood gas composition, assessed comprehensively in terms of the integral scales of assessment of severity. The study was derived a mathematical formula that calculates the possibility of a positive response to the high-frequency ventilation for a particular patient.С целью выяснения возможности применения высокочастотной искусственной вентиляции легких в комплексе респираторной терапии СОЛП/ОРДС, было обследовано 47 пациентов с клинико - диагностическими критериями данного синдрома, которым в процессе респираторной терапии наряду с вентиляцией, контролируемой по давлению, проводилась высокочастотная искусственная вентиляция легких. У всех пациентов исследовались биомеханические свойства легких, кислотно - основное состояние и газовый состав крови, проводилась комплексная оценка с позиций интегральных шкал оценки тяжести. В результате проведенного исследования была выведена математическая формула, позволяющая рассчитать возможность положительного ответа на высокочастотную вентиляцию легких для конкретного пациента

A quantitative theory-versus-experiment comparison for the intense laser dissociation of H2+

A detailed theory-versus-experiment comparison is worked out for H$_2^+$ intense laser dissociation, based on angularly resolved photodissociation spectra recently recorded in H.Figger's group. As opposite to other experimental setups, it is an electric discharge (and not an optical excitation) that prepares the molecular ion, with the advantage for the theoretical approach, to neglect without lost of accuracy, the otherwise important ionization-dissociation competition. Abel transformation relates the dissociation probability starting from a single ro-vibrational state, to the probability of observing a hydrogen atom at a given pixel of the detector plate. Some statistics on initial ro-vibrational distributions, together with a spatial averaging over laser focus area, lead to photofragments kinetic spectra, with well separated peaks attributed to single vibrational levels. An excellent theory-versus-experiment agreement is reached not only for the kinetic spectra, but also for the angular distributions of fragments originating from two different vibrational levels resulting into more or less alignment. Some characteristic features can be interpreted in terms of basic mechanisms such as bond softening or vibrational trapping.Comment: submitted to PRA on 21.05.200