High frequency limit of the Transport Cross Section and boundedness of the Total Cross Section in scattering by an obstacle with impedance boundary conditions

The scalar scattering of the plane wave by a strictly convex obstacle with impedance boundary conditions is considered. The uniform boundedness of the Total Cross Section for all values of frequencies is proved. The high frequency limit of the Transport Cross Section is founded and presented as a classical functional of the variational theory

Invisibility in billiards

The question of invisibility for bodies with mirror surface is studied in the framework of geometrical optics. We construct bodies that are invisible/have zero resistance in two mutually orthogonal directions, and prove that there do not exist bodies which are invisible/have zero resistance in all possible directions of incidence

Spectral properties of the Dirichlet-to-Neumann operator for exterior Helmholtz problem and its applications to scattering theory

We prove that the Dirichlet-to-Neumann operator (DtN) has no spectrum in the lower half of the complex plane. We find several application of this fact in scattering by obstacles with impedance boundary conditions. In particular, we find an upper bound for the gradient of the scattering amplitude and for the total cross section. We justify numerical approximations by providing bounds on difference between theoretical and approximated solutions without using any a priory unknown constants

Characterization of the binding sites of the anticancer ruthenium(III) complexes KP1019 and KP1339 on human serum albumin via competition studies

Indazolium trans-[tetrachloridobis(1H-indazole)ruthenate(III)] (KP1019) and its Na+ analogue (KP1339) are two of the most prominent non-platinum antitumor metal complexes currently undergoing clinical trials. After intravenous administration, they are known to bind to human serum albumin (HSA) in a noncovalent manner. To elucidate their HSA binding sites, displacement reactions with the established site markers warfarin and dansylglycine as well as bilirubin were monitored by spectrofluorimetry, ultrafiltration-UV-vis spectrophotometry, and/or capillary zone electrophoresis. Conditional stability constants for the binding of KP1019 and KP1339 to sites I and II of HSA were determined, indicating that both Ru(III) compounds bind to both sites with moderately strong affinity (log K (1)' = 5.3-5.8). No preference for either binding site was found, and similar results were obtained for both metal complexes, demonstrating low influence of the counter ion on the binding event

Structural insights into thrombolytic activity of destabilase from medicinal leech

Destabilase from the medical leech Hirudo medicinalis belongs to the family of i-type lysozymes. It has two different enzymatic activities: microbial cell walls destruction (muramidase activity), and dissolution of the stabilized fibrin (isopeptidase activity). Both activities are known to be inhibited by sodium chloride at near physiological concentrations, but the structural basis remains unknown. Here we present two crystal structures of destabilase, including a 1.1 Å-resolution structure in complex with sodium ion. Our structures reveal the location of sodium ion between Glu34/Asp46 residues, which were previously recognized as a glycosidase active site. While sodium coordination with these amino acids may explain inhibition of the muramidase activity, its influence on previously suggested Ser49/Lys58 isopeptidase activity dyad is unclear. We revise the Ser49/Lys58 hypothesis and compare sequences of i-type lysozymes with confirmed destabilase activity. We suggest that the general base for the isopeptidase activity is His112 rather than Lys58. pKa calculations of these amino acids, assessed through the 1 μs molecular dynamics simulation, confirm the hypothesis. Our findings highlight the ambiguity of destabilase catalytic residues identification and build foundations for further research of structure–activity relationship of isopeptidase activity as well as structure-based protein design for potential anticoagulant drug development.</p

ПРОЕКТНО-КОНТЕКСТНОЕ ОБРАЗОВАНИЕ В РЕАЛИЗАЦИИ МНОГОУРОВНЕВОЙ ПОДГОТОВКИ ЭКОНОМИСТОВ

The dynamics of modern society and the growth of innovative economy needs lead to shortening of graduates’ periods of adaptation to professional activity, growing of their mobility, competitiveness, and make the professional education face new tasks.Authors discuss the problem of multilevel economic education organization, aimed at elimination of the gap between employers requirements and assignable educational services. The necessity of development of projectcontextual education technology is being proved. It creates an opportunity of competence approach realization. In the article Financial University’s experience is showed to develop and introduce the educational standard „Economics” in the practice of training personnel for innovative economy. This experience defi nes the opportunity of designing the educational process according to „weighting coeffi cient” of particular competences importance and systematic unity of higher education levels. Динамичность современного общества, рост потребностей инновационной экономики обусловливают сокращение сроков адаптации выпускников вузов к профессиональной деятельности, повышение их мобильности, конкурентоспособности и ставят перед профессиональным образованием новые задачи. Авторами обсуждается проблема организации многоуровневого экономического образования, направленного на устранение разрыва между требованиями работодателей и предоставляемыми образовательными услугами. Обоснована необходимость разработки технологии проектно-контекстного обучения, создающей возможность содержательной реализации компетентностного подхода.Представленный в статье опыт Финансового университета при Правительстве РФ по разработке и внедрению Образовательного стандарта высшего образования по направлению «Экономика» в практику подготовки кадров для инновационной экономики определяет возможность проектирования образовательного процесса в соответствии с «весовым коэффициентом» важности отдельных компетенций и системном единстве уровней высшего образования.

Identification of a mitotic recombination hotspot on chromosome III of the asexual fungus Aspergillus niger and its possible correlation elevated basal transcription

Genetic recombination is an important tool in strain breeding in many organisms. We studied the possibilities of mitotic recombination in strain breeding of the asexual fungus Aspergillus niger. By identifying genes that complemented mapped auxotrophic mutations, the physical map was compared to the genetic map of chromosome III using the genome sequence. In a program to construct a chromosome III-specific marker strain by selecting mitotic crossing-over in diploids, a mitotic recombination hotspot was identified. Analysis of the mitotic recombination hotspot revealed some physical features, elevated basal transcription and a possible correlation with purine stretches

Intensification of extraction of phytocomponents from berry raw materials

Abstract The paper describes the methods of extraction of biologically active agents of berry raw materials. The purpose of the study was to select the parameters of phytocomponents extraction during ultrasonic treatment of berry raw materials. The batch method of maceration using water-ethanol extractants was studied. The raw material was irradiated with Volna-M ultrasonic device. The kinetics of extracting phenolic compounds from fresh black currant berries (Ribes nigrum L.) was studied. Physical-chemical and microbiological indicators were determined using standard methods. Composition and quantitative content of flavonoids and tanning agents in extracts were determined by colorimetric and high performance liquid chromatography techniques. Mathematical statistics and analysis were used in data processing. The diffusion properties of extracts were calculated in a computer program. The experiments were performed in five-fold repetition, and the data were analyzed to determine their validity in application packages. It was found that the duration of extraction during ultrasonic treatment is reduced by an average of 60 times, while increasing the yield of extractive substances. The obtained kinetic dependencies of diffusion characteristics of the raw material reveal that more complete extraction of flavonoid compounds takes place with water-ethanol extractants (40% wt.) at irrigation module 1 to 15 and 1 to 20. The analysis of physical and chemical composition of solutions showed high content of biologically active substances. The extract is recommended as components of functional products.</jats:p