The problems of adolescent relationships with parents

The article discusses the relationship between the teenager with parents and ways to resolve the conflict between themВ статье рассматриваются взаимоотношения подростка с родителями и способы урегулирования конфликта между ним

Efficient Encoding of Matrix Microparticles with Nanocrystals for Fluorescent Polyelectrolyte Microcapsules Development

Polyelectrolyte microcapsules development and further use as specific carriers for drug molecules, fluorescent dyes, and metal nanoparticles is a promising approach to designing theranostic agents. Semiconductor nanocrystal quantum dots exhibiting size-dependent optical properties, a high photostability, and optimal fluorescent properties can be advantageous over classical organic fluorophores. The results of elaboration of efficient encoding of matrix microparticles with nanocrystals for development of fluorescent polyelectrolyte microcapsules and the characteristics of the obtained encoded microbeads are demonstrated. Keywords: Semiconductor nanocrystals; encoding of matrix microbeads; theranostic agents, polyelectrolyte microcapsules, layer-by-layer technique

Cytotoxicity of Polyelectrolyte Microcapsules Encoded with Semiconductor Nanocrystals

Polyelectrolyte microcapsules are promising carriers of drugs and diagnostic agents for designing targeted and controlled delivery systems design. The use of quantum dots (QDs) as fluorescent labels in bioimaging is a promising approach to bioimaging tool development. The potential toxicity of QDs makes their applicability as fluorescent labels in vivo questionable. Therefore, the cytotoxicity of polyelectrolyte microcapsules encoded with semiconductor nanocrystals has been investigated. Keywords: Polyelectrolyte microcapsules, semiconductor nanocrystals, cytotoxicity, theranostic agents

Highly Stable, Water-Soluble CdSe/ZnS/CdS/ZnS Quantum Dots with Additional SiO2 shell

Quantum dots (QDs) are fluorescent nanocrystals extensively used today in research and applications. They attract much interest due to the high photostability and fluorescence quantum yields close to 100%. The best QDs are made by synthesis in organic media, and they have to be transferred into aqueous solutions if biomedical applications are concerned. An advanced method for rendering QDs water-soluble is to coat them with hydrophilic SiO2 -layer. However, growing a silica shell with a predetermined thickness is a problem, because uncertain values of the molar extinction coefficients (ε) of core/shell QDs made it impossible to calculate precise yields of the chemical reactions involved. Here we suggest an approach to solving this problem by constructing the structural models of per se and silica-coated QDs followed by measuring ε in a course of the QD synthesis, thus carrying out precise quantitative reactions. Proceeding in such a way, we prepared the CdSe/ZnS/CdS/ZnS QDs with the structure predicted by the model and coated by silica shell. Prepared QDs are characterized by a narrow size distribution and the same fluorescence parameters as the original QDs in the organic medium. Developed approach permitted efficient QDs water-solubilisation and preparation of stable nanoparticles for plethora of biomedical applications.     Keywords: Quantum dots, QD, silica shell, core-shel

К ПРИБЛИЖЕННОМУ ИНТЕГРИРОВАНИЮ СИЛЬНО ОСЦИЛЛИРУЮЩИХ ФУНКЦИЙ

Elementary approximate formulae for numerical integration of functions containing oscillating factors of a special form with a parameter have been proposed in the paper. In this case general quadrature formulae can be used only at sufficiently small values of the parameter. Therefore, it is necessary to consider in advance presence of strongly oscillating factors in order to obtain formulae for numerical integration which are suitable in the case when the parameter is changing within wide limits. This can be done by taking into account such factors as weighting functions. Moreover, since the parameter can take values which cannot always be predicted in advance, approximate formulae for calculation of such integrals should be constructed in such a way that they contain this parameter in a letter format and they are suitable for calculation at any and particularly large values of the parameter. Computational rules with such properties are generally obtained by dividing an interval of integration into elementary while making successive approximation of the integral density at each elementary interval with polynomials of the first, second and third degrees and taking the oscillating factors as weighting functions. The paper considers the variant when density of the integrals at each elementary interval is approximated by a polynomial of zero degree that is a constant which is equal to the value of density in the middle of the interval. At the same time one approximate formula for calculation of an improper integral with infinite interval of the function with oscillating factor of a special type has been constructed in the paper. In this case it has been assumed that density of the improper integral rather quickly goes to zero when an argument module is increasing indefinitely. In other words it is considered as small to negligible outside some finite interval. Uniforms in parameter used for evaluation of errors in approximate formulae have been obtained in the paper and they make it possible to calculate integrals with the required accuracy.Построены и исследованы простейшие приближенные формулы для численного интегрирования функций, содержащих осциллирующие множители специального вида с параметром. Общие квадратурные формулы в этом случае могут быть использованы только при достаточно малых значениях параметра. Следовательно, чтобы получить формулы численного интегрирования, пригодные при изменении параметра в широких границах, необходимо заранее учитывать наличие сильно осциллирующих множителей. Это можно сделать, принимая, например, такие множители за весовые функции. Кроме того, поскольку параметр способен принимать значения, которые заранее предвидеть не всегда можно, приближенные формулы для вычисления таких интегралов необходимо строить так, чтобы они содержали этот параметр в буквенном виде и были пригодны для вычисления при любых, в частности при больших, значениях параметра. Вычислительные правила, обладающие такими свойствами, обычно получают путем разбиения промежутка интегрирования на элементарные с последующим приближением плотности интеграла на каждом элементарном промежутке многочленами первой, второй и третьей степеней, принимая при этом осциллирующие множители за весовые функции. В статье рассмотрен тот вариант, когда плотность интегралов на каждом элементарном промежутке аппроксимируется многочленом нулевой степени – константой, равной значению плотности в середине этого промежутка. Попутно сконструирована одна приближенная формула для вычисления несобственного интеграла по бесконечному промежутку от функции, содержащей осциллирующий множитель специального вида. При этом предполагали, что плотность несобственного интеграла достаточно быстро стремится к нулю, когда модуль аргумента неограниченно возрастает. Другими словами, она считается пренебрежимо малой вне некоторого конечного отрезка. Получены равномерные по параметру оценки погрешностей приближенных формул, позволяющие вычислять интегралы с заданной точностью

APPROXIMATE INTEGRATION OF HIGHLY OSCILLATING FUNCTIONS

Elementary approximate formulae for numerical integration of functions containing oscillating factors of a special form with a parameter have been proposed in the paper. In this case general quadrature formulae can be used only at sufficiently small values of the parameter. Therefore, it is necessary to consider in advance presence of strongly oscillating factors in order to obtain formulae for numerical integration which are suitable in the case when the parameter is changing within wide limits. This can be done by taking into account such factors as weighting functions. Moreover, since the parameter can take values which cannot always be predicted in advance, approximate formulae for calculation of such integrals should be constructed in such a way that they contain this parameter in a letter format and they are suitable for calculation at any and particularly large values of the parameter. Computational rules with such properties are generally obtained by dividing an interval of integration into elementary while making successive approximation of the integral density at each elementary interval with polynomials of the first, second and third degrees and taking the oscillating factors as weighting functions. The paper considers the variant when density of the integrals at each elementary interval is approximated by a polynomial of zero degree that is a constant which is equal to the value of density in the middle of the interval. At the same time one approximate formula for calculation of an improper integral with infinite interval of the function with oscillating factor of a special type has been constructed in the paper. In this case it has been assumed that density of the improper integral rather quickly goes to zero when an argument module is increasing indefinitely. In other words it is considered as small to negligible outside some finite interval. Uniforms in parameter used for evaluation of errors in approximate formulae have been obtained in the paper and they make it possible to calculate integrals with the required accuracy

Design and characterisation of calcium carbonate microspheres for anticancer drug delivery

International audienceThe development of delivery systems providing prolonged release of antitumor drugs represents one of the challenges in designing and optimization of novel tools for cancer therapy. The employment of spherical inorganic microparticles, in particular, calcium carbonate vaterite microspheres, as microcarriers appears promising because of their porous, matrix structure, biocompatibility, and biodegradability. Here, we summarize the results of the development of the approaches to synthesis of calcium carbonate vaterite microspheres with narrowed size distribution and microencapsulation of low-molecular-weight anticancer drugs, such as doxorubicin hydrochloride into obtained microspheres. Supplementing the reaction mixture with a thickener defines fabrication of homogeneous vaterite microparticles with a spherical shape and an average size of 2 to 3 μm. Synthesised microspheres ensure prolonged release of doxorubicin at physiological pH values and can be used as a delivery system and as a structural component for development of a theranostic platform for tumour treatment and diagnosis

Surface-enhanced Raman scattering of CoV-SARS-2 viral proteins in a strong coupling regime

International audienceFast, sensitive, high-throughput detection of coronavirus antigens at physiologically relevant levels is essential for population screening that could prevent epidemics such as the current COVID-19 global pandemic. Optical methods based on surface-enhanced Raman scattering (SERS) spectroscopy are promising for this purpose because they ensure quick detection of even single biological molecules in a sample. For achieving such a high sensitivity, it is crucial to design SERS-active systems concentrating incident radiation into small sample volumes. Here, metal-dielectric cavities have been obtained through interaction of protein sulfhydryl groups with a SERS-active silver surface. The concentration of light in these cavities allows the differential detection of spike glycoprotein and nucleocapsid protein of SARS-COV-2, which are its key antigens, at physiologically relevant concentrations. The cavity Q-factor can be increased by additionally covering the dielectric protein film with a silver shell to form an ultrathin cavity, which provides an at least tenfold enhancement of the detection signal. The results could be used to design high-throughput systems for specific and sensitive detection of viral antigens and quick diagnosis of viral infections