DNA Interaction with a Polyelectrolyte Monolayer at Solution—Air Interface

The formation of ordered 2D nanostructures of double stranded DNA molecules at various interfaces attracts more and more focus in medical and engineering research, but the underlying intermolecular interactions still require elucidation. Recently, it has been revealed that mixtures of DNA with a series of hydrophobic cationic polyelectrolytes including poly(N,N-diallyl-N-hexyl-N-methylammonium) chloride (PDAHMAC) form a network of ribbonlike or threadlike aggregates at the solution—air interface. In the present work, we adopt a novel approach to confine the same polyelectrolyte at the solution—air interface by spreading it on a subphase with elevated ionic strength. A suite of techniques–rheology, microscopy, ellipsometry, and spectroscopy–are applied to gain insight into main steps of the adsorption layer formation, which results in non-monotonic kinetic dependencies of various surface properties. A long induction period of the kinetic dependencies after DNA is exposed to the surface film results only if the initial surface pressure corresponds to a quasiplateau region of the compression isotherm of a PDAHMAC monolayer. Despite the different aggregation mechanisms, the micromorphology of the mixed PDAHMAC/DNA does not depend noticeably on the initial surface pressure. The results provide new perspective on nanostructure formation involving nucleic acids building blocks

МОДЕЛЬ СЦЕНАРИЯ ИНТРОДУКЦИИ МОЛОДИ РЫБ С УЧЕТОМ ДИНАМИКИ БИОГЕННЫХ ЭЛЕМЕНТОВ

The article discusses the expansion of the previously formulated approach to modeling aspects of the reproductive cycle, taking into account the changes in the habitat and metamorphosis in the development of fish. Excessive accumulation of nutrients with prolonged use of a reservoir for artificial growth of juveniles or accelerated decomposition of organic nitrogen and phosphorus may in some cases affect the success of the reproductive process. This creates an indirect effect on long-term trends in population dynamics. In some cases, the increase in the influx of organic phosphorus further leads to a state of eutrophication and may affect the insufficient aeration of breeding sites, leading to hypoxia for hatched larvae. Even worsen the situation with the consumption of oxygen in the water at the mass destruction of eggs. Lack of organic matter leads to insufficient development of planktonic organisms for optimal growth of fishes. The system of survivability equations for calculation competing individuals of the generation is supplemented by a functional extension using an iterative model of biogenic elements dynamics, based on the analysis of processes in the ecosystem of Lake Chao. The block of the model for calculating the inflow and destruction of organic matter is synchronized with a continuous-discrete computational structure that takes into account the interrelated changes in mortality factors and the rate of development of juvenile fish during transitions between generalized ecological and physiological stages of development.Рассматривается расширение ранее сформулированного подхода к моделированию аспектов репродуктивного цикла с учетом происходящих перемен в среде обитания и метаморфозов в развитии рыб. Избыточное накопление биогенных элементов при длительном использовании водоемов для искусственного выращивания молоди или ускоренный распад органики в некоторых случаях могут оказывать влияние на успешность процесса воспроизводства, косвенно влияя на долговременные тренды популяционной динамики. В отдельных случаях усиление притока органического фосфора приводит далее к состоянию эвтрофикации и может сказаться на недостаточной аэрации мест размножения, привести к гипоксии у вылупившихся личинок. При массовой гибели икры еще ухудшится ситуация с расходом кислорода в водоеме. Нехватка органики приводит недостаточному для оптимального роста рыб развитию биомассы кормовых планктонных организмов. Система уравнений выживаемости конкурирующих особей поколения дополнена функциональным расширением, использующим итерационную модель динамики биогенных элементов, построенную на основе анализа процессов в экосистеме озера Чао. Блок модели расчёта притока и деструкции органики синхронизирован с непрерывно-дискретной вычислительной структурой, учитывающей взаимосвязанные изменения факторов смертности и темпов развития молоди рыб при переходах между обобщенными эколого-физиологическими этапами развития

Control of the bias tilt angles in nematic liquid crystals

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in S. V. Yablonskii, K. Nakayama, S. Okazaki, M. Ozaki, K. Yoshino, S. P. Palto, M. Yu. Baranovich, and A. S. Michailov, Journal of Applied Physics 85, 2556 (1999) and may be found at https://doi.org/10.1063/1.369574

DNA Interaction with a Polyelectrolyte Monolayer at Solution—Air Interface

From MDPI via Jisc Publications RouterHistory: accepted 2021-08-19, pub-electronic 2021-08-22Publication status: PublishedFunder: Russian Science Foundation; Grant(s): № 21-13-00039The formation of ordered 2D nanostructures of double stranded DNA molecules at various interfaces attracts more and more focus in medical and engineering research, but the underlying intermolecular interactions still require elucidation. Recently, it has been revealed that mixtures of DNA with a series of hydrophobic cationic polyelectrolytes including poly(N, N-diallyl-N-hexyl-N-methylammonium) chloride (PDAHMAC) form a network of ribbonlike or threadlike aggregates at the solution—air interface. In the present work, we adopt a novel approach to confine the same polyelectrolyte at the solution—air interface by spreading it on a subphase with elevated ionic strength. A suite of techniques–rheology, microscopy, ellipsometry, and spectroscopy–are applied to gain insight into main steps of the adsorption layer formation, which results in non-monotonic kinetic dependencies of various surface properties. A long induction period of the kinetic dependencies after DNA is exposed to the surface film results only if the initial surface pressure corresponds to a quasiplateau region of the compression isotherm of a PDAHMAC monolayer. Despite the different aggregation mechanisms, the micromorphology of the mixed PDAHMAC/DNA does not depend noticeably on the initial surface pressure. The results provide new perspective on nanostructure formation involving nucleic acids building blocks

DNA Penetration into a Lysozyme Layer at the Surface of Aqueous Solutions

The interactions of DNA with lysozyme in the surface layer were studied by performing infrared reflection–absorption spectroscopy (IRRAS), ellipsometry, surface tensiometry, surface dilational rheology, and atomic force microscopy (AFM). A concentrated DNA solution was injected into an aqueous subphase underneath a spread lysozyme layer. While the optical properties of the surface layer changed fast after DNA injection, the dynamic dilational surface elasticity almost did not change, thereby indicating no continuous network formation of DNA/lysozyme complexes, unlike the case of DNA interactions with a monolayer of a cationic synthetic polyelectrolyte. A relatively fast increase in optical signals after a DNA injection under a lysozyme layer indicates that DNA penetration is controlled by diffusion. At low surface pressures, the AFM images show the formation of long strands in the surface layer. Increased surface compression does not lead to the formation of a network of DNA/lysozyme aggregates as in the case of a mixed layer of DNA and synthetic polyelectrolytes, but to the appearance of some folds and ridges in the layer. The formation of more disordered aggregates is presumably a consequence of weaker interactions of lysozyme with duplex DNA and the stabilization, at the same time, of loops of unpaired nucleotides at high local lysozyme concentrations in the surface layer

ИННОВАЦИОННАЯ СПЕЦИФИЧЕСКАЯ ПРОДУКЦИЯ: ОРГАНИЧЕСКИЕ РОСТКИ (MICROGREENS) И СЕЯНЦЫ (BABY LEAFS)

The assortment of salad crops, process parameters for production of seedlings (Baby leaf) and sprouts (Microgreens) is presented. The principles of the selection and sale of salad crops in the local market are recommended.Представлен ассортимент салатных культур, технологические параметры для производства их сеянцев (Baby leaf) и ростков (Microgreens). Предложены принципы подбора и продажи салатных культур на местном рынке

Spread Layers of Lysozyme Microgel at Liquid Surface

The spread layers of lysozyme (LYS) microgel particles were studied by surface dilational rheology, infrared reflection–absorption spectra, Brewster angle microscopy, atomic force microscopy, and scanning electron microscopy. It is shown that the properties of LYS microgel layers differ significantly from those of ß-lactoglobulin (BLG) microgel layers. In the latter case, the spread protein layer is mainly a monolayer, and the interactions between particles lead to the increase in the dynamic surface elasticity by up to 140 mN/m. In contrast, the dynamic elasticity of the LYS microgel layer does not exceed the values for pure protein layers. The compression isotherms also do not exhibit specific features of the layer collapse that are characteristic for the layers of BLG aggregates. LYS aggregates form trough three-dimensional clusters directly during the spreading process, and protein spherulites do not spread further along the interface. As a result, the liquid surface contains large, almost empty regions and some patches of high local concentration of the microgel particles

Social and professional psychological potrait of the residents as basis of their training proffesional activity

the article presents the results of the study of residents in order to compile a social and professional -psychological portrait as the basis of training for professional activities of medical specialistsв статье представлены результаты исследования ординаторов с целью составления социально и профессионально- психологического портрета как подготовки к профессиональной деятельности медицинских специалисто

Structural and luminescent characteristics of YAG phosphors synthesized in the radiation field

YAG:Ce, YAGG:Ce ceramics were obtained by sintering the oxide powders in the radiation field. The results of investigations of the structure, composition and luminescence of ceramics are presented. The luminescence characteristics of powders exactly correspond to the phosphors luminescence used in practice obtained by solid-state synthesis methods. It has been established that in the used radiation exposure modes the main factor determining the efficiency of the synthesis is the ionization density