Recently ferroelectric properties have been found in hafnia-based nanosized films. Such films are of the utmost interest for development of a universal memory, which combines the advantages of random access memory and flash memory. The paper studies optical properties of hafnia-zirconium oxide films H-fxZryO2 and lanthanum-alloyed hafnia-zirconium oxide films La:HfxZryO2. Fluctuations of thickness in HfxZryO2 do not exceed 3.5

Recently ferroelectric properties have been found in hafnia-based nanosized films. Such films are of the utmost interest for development of a universal memory, which combines the advantages of random access memory and flash memory. The paper studies optical properties of hafnia-zirconium oxide films HfxZryO2 and lanthanum-alloyed hafnia-zirconium oxide films La : HfxZryO2. Fluctuations of thickness in HfxZryO2 do not exceed 3.5%, fluctuations of thickness in La : HfxZryO2 films --- 3.2%. Optical properties are analyzed based on effective-medium theory. According to effective-medium theory data, HfxZryO2 films contain 46% HfO2, 54% ZrO2, La : HfxZryO2 films contain 47.5% HfO2, 52.4% ZrO2, 2.5% La2O3. Keywords: ferroelectric, refraction index, spectral ellipsometry, effective-medium theory.

The paper considers the main algorithms for generating various school subject problems of closed and open type. Some of these algorythms (i.e. question answering, Visual question answering) use artificial intelligence and some not (i.e. sets of AND/OR tree, templates). It was shown that methods for generating tests using artificial intelligence have a high potential, but they require further development, in particular, the creation of large question-answer database in russian language.

Currently, a new generation of high-speed, information-intensive resistive memory based on nonstoichiometric dielectrics is being developed. The electron structure of nonstoichiometric silicon oxide SiO x is set by the value of parameter x . It is found that the treatment of thermal SiO 2 in hydrogen plasma electron cyclotron resonance leads to the enrichment of silicon oxide with excess silicon, which in turn leads to the appearance of electron and hole traps in SiO x . SiO x conductivity is bipolar: electrons are injected from negatively biased silicon and holes are injected from positively biased silicon. Cathodoluminescence (CL) experiments confirm the assumption that the traps in SiO x are due to the excess silicon. p ++-Si(100)/SiO x /Ni memristor metal-dielectric-semiconductor (MDS) structures are fabricated based on the developed procedure for the preparation of nonstoichiometric oxide in hydrogen plasma of electron cyclotron resonance. Such structures have the properties of resistive switching of SiO x that do not require a forming operation.

The optical and electrochromic properties of thin films obtained by centrifugation from solutions containing ambipolar polyimides with pendant groups based on 9H-thioxanthene-9-one and its S-dioxide derivative are studied using spectral ellipsometry, spectrophotometry, and spectroelectrochemistry. It is shown that the spectral dependences of the refractive index n(E) and the absorption coefficient α(E) as well as the electrochromic properties of polyimide thin films under electrochemical reduction and oxidation conditions strongly depend on the type of the pendant group. Based on the estimates of the band gap Eg a conclusion is made about the possible promising use of thin films of polyimides as working layers in memristors of a new type. Keywords: memristors, dielectric films, ambipolar polyimides, ellipsometry, electrochromism.

The aim of the study was to identify fatty acids (FA) of erythrocyte membranes and blood serum, which can serve as potential biomarkers for early detection of colorectal cancer.Material and methods. the study involved 65 patients with stage I-II CRC (mean age 63,3 ± 9,6 years (30 men, 35 women) and 35 people in the comparison group, matched by age and sex. the composition of fatty acids of erythrocyte membranes and blood serum was studied using a gc/ms system based on three agilent 7000B quadrupoles (USA). methods of the MATLAB software (R2019a, MathWorks) and the R programming language were used for statistical processing: t-test, unsupervised principal component analysis (PCA), Fold change, Volcano plot, machine learning method (Random Forest), Roc analysis, Heatmaps.Results. patients with stage I-II CRC showed a decrease in the level of saturated, individual monounsaturated fatty acids and a highly significant increase in the most of the polyunsaturated fatty acids with a predominance of omega-3. For most of the fatty acid levels, significant differences in erythrocyte membranes and serum between the groups were found. the levels of erythrocyte myristic, pentadecanoic, 7-palmitoleic, saturated/polyunsaturated Fa ratios (the content of which was significantly lower at stages I-II CRC than those in the control) and the levels of α-linolenic, eicosapentaenoic, docosapentaenoic, docosahexaenoic, the amount of omega-3 Fa, EPA + DHA, docodienic, dihomo-γ-linolenic, docatetraenoic fatty acids (the content of which was significantly higher in colorectal cancer than those in healthy subjects) were the most discriminating parameters in distinguishing patients with I-II stage CRC and healthy individuals. in the blood serum, the level of biomarkers had the following fatty acids: arachidonic, myristic, docosahexaenoic, the amount of omega 3 puFa, the ratio of omega 6/omega 3 puFa, pentadecanoic, docosapentaenoic, and docodiene. a model that included a list of fatty acids, such as С14:0, С15:0, С16:1;7, С18:3 n-3, C20:2 n-6, C20:3 n-6, C20:5 n-3, C22:4 n-6, C22:5 n-3, C22:6 n-3, sum of omega-3, omega-3 (EPA + DHA), and saturated / polyunsaturated fatty acids ratio provided auc 0,916 with a specificity of 0,90 and sensitivity of 0,95 in distinguishing patients with stage I-II CRC from healthy individuals.Conclusion. the study of the levels and ratios of fatty acids in erythrocyte membranes and blood serum should be considered a promising trend in the search for biomarkers for the early diagnosis of colorectal cancer.

The aim of this work is to study the possibility of using blood serum (BS) fatty acids (FA) and erythrocytes (ER) as diagnostic markers of the severity of NAFLD. Materials and methods. We examined 52 patients with NAFLD (51.8 ± 3.9 years), confirmed by the NLFS index, and 20 apparently healthy men (49.2 ± 4.5 years). The degree of liver fibrosis was established by indirect elastometry (FibroScan® 502 Echosens, France). 27 patients had an initial degree of fibrosis (F0-1), 25 had severe fibrosis (F2-4). The study of the composition of fatty acids of Er and BS was carried out using a GC / MS system based on three Agilent 7000B quadrupoles (USA). Results. Significant differences in the levels of fatty acids in blood serum and erythrocyte membranes in patients with NAFLD were revealed, associated with the degree of fibrosis and necroinflammatory activity. To distinguish between mild and severe fibrosis in NAFLD, the levels of saturated fatty acids (myristic, pentadecane, margarine) and omega-3 PUFAs (eicosapentaenoic, docosapentaenoic, docosahexaenoic) were found to be significant (p = 0.002-0.0003). Saturated and monounsaturated FAs (palmitelaidic, palmitoleic, vaccenic) played a key role in differentiating the degree of necroinflammatory activity (minimal versus pronounced) (p = 0.03-0.005). The created diagnostic panels (FA of blood serum and erythrocyte membranes) made it possible to differentiate patients with NAFLD with varying degrees of fibrosis. Correlations of FA levels in erythrocyte membranes and blood serum with manifestations of metabolic syndrome, indicators of liver damage in patients with NAFLD were revealed. Conclusions. The established differences in fatty acid profiles of blood serum and erythrocyte membranes in patients with NAFLD, associated with the degree of fibrosis, necroinflammatory activity, manifestations of metabolic syndrome and indicators of liver damage, should be considered as promising biomarkers for assessing the severity of NAFLD.

The aim of this study is to study the characteristics of the fatty acid composition of erythrocyte membranes and blood serum in patients with IBD associated with the stage of the disease, followed by the determination of biomarkers that are significant for determining the activity of IBD. Materials and methods.We examined 109 patients (mean age 37.7 ± 11.7 years, 59 women, 50 men) with IBD and 53 examined comparison groups (mean age 43.3 ± 11.7 years).The group of patients with IBD included patients with ulcerative colitis -50 people, with Crohn's disease -41 people and 18 patients with unclassified colitis.36 patients were examined in dynamics during the year.Taking into account the dynamics, 109 cases of exacerbation of IBD and 36 cases of disease remission were identified.The study of the composition of fatty acids Er and SA was carried out using a GC / MS system based on three Agilent 7000B quadrupoles (USA).Results..In patients with IBD, an increase in the content of saturated fatty acids (mainly due to palmitic, stearic fatty acids) during the period of exacerbation of the disease compared with healthy individuals was revealed, followed by a decrease in the onset of remission (p <0.05).The total content of unsaturated fatty acids is significantly lower in patients with IBD in the exacerbation stage compared to the control group КЛИНИЧЕСКАЯ МЕДИцИНА 161 Серия: Естественные и технические науки №5 май 2021 г.

С помощью метода диэлектрофореза в неоднородном переменном электрическом поле при использовании оптической системы детекции клеток проведено исследование электрических и вязкоупругих параметров эритроцитов в частотном диапазоне от 5·104 до 1·106 MHz у 129 больных с колоректальным раком (КРР) различных стадий развития заболевания, 25 человек с аденоматозными полипами и 35 лиц группы сравнения. Показано, что величины физических характеристик эритроцитов значимо различаются как при сопоставлении групп контроля и пациентов с аденоматозными полипами и больных с ранними стадиями КРР, так и при сравнении пациентов с различными стадиями онкологического процесса между собой. Построение SHAP-графиков на основе электрических и вязкоупругих параметров эритроцитов позволило достичь 100% диагностической точности при различении пациентов с аденоматозными полипами, ранними стадиями КРР от здоровых лиц, 98.7% точности --- при дифференцировании пациентов с полипами от больных с ранними стадиями КРР, 91.9% точности --- при различении ранних и поздних стадий КРР. Полученные результаты демонстрируют высокий потенциал предложенного метода для скрининга и диагностики КРР. Ключевые слова: диэлектрофорез, эритроциты, электрические и вязкоупругие параметры, диагностика, колоректальный рак, аденоматозные полипы, SHAP-графики.

The aim of this work is to study the features of the electrical and viscoelastic parameters of erythrocytes in patients with inflammatory bowel diseases (ulcerative colitis, Crohn’s disease, unclassified colitis), taking into account the stage of the disease for possible use in differential diagnosis.The electrical and viscoelastic parameters of erythrocytes were studied using dielectrophoresis in 109 patients with IBD, mean age 37,7 + 11,7 years (50 patients with ulcerative colitis (UC), 41 with Crohn’s disease (CD), 18 with unclassified colitis (UCC) and 53 conditionally healthy, comparable in age and sex with the main groups.Red blood cells of individuals with IBD differed from those in the comparison group by a smaller average diameter, an increased proportion of deformed, spherocytic cells with a changed surface character with a reduced ability to deform, a lower level of surface charge of cells, an altered membrane structure with an increased ability to conduct electric current, prone to destruction and the formation of aggregates (p <0,0001–0,05).Analysis in individual groups with IBD in the acute stage, taking into account the therapy, revealed significant differences between the forms of IBD: in patients with Crohn’s disease, in contrast to patients with UC, red blood cells had lower values of the amplitude of deformation, capacity, dipole moment, and velocity of movement of cells towards electrodes, the proportion of discocytes, polarizability at most of the frequencies of the electric field (p <0,00001–0,05). On the contrary, the summarized indicators of rigidity, viscosity, electrical conductivity, aggregation and destruction indices were higher in CD than in UC (p <0,0001–0,05). CD patients had a greater number of deformed cells with altered surface character (p <0,00001).The features of the electrical and viscoelastic parameters of erythrocytes in patients with differentnosological forms of IBD can be used for the differential diagnosis of ulcerative colitis and Crohn’s disease in case of colon lesions, in the long term — for verification of the diagnosis in unclassified colitis.

The influence of InAlAs/InP(001) heterostructures surface morphology on the optical properties (dispersive refractive index and extinction coefficient) of the anodic layer, formed by the oxidation in low-energy Townsend gas-discharge O2-Ar-containing plasma at room temperature, was studied using atomic force microscopy and ellipsometry methods. High resolution transmission electron microscopy and X-ray photoelectron spectroscopy were used to determine the anodic layer morphology and chemical composition. It is shown that the growth structural defects (pits) on the InAlAs surface, with a density 106-107 cm-2, do not significantly influence the optical properties of the amorphous anodic layers, mainly consisting of In2O3, Al2O3, As2O3 and elemental arsenic quite uniformly distributed over their depth and area. The thickness of thin (<= 10 nm) oxide layers on InAlAs is measured at a high accuracy by the nondestructive ellipsometry method using the optical model of a single-layer isotropic film on an absorbing substrate.

The luminescent and optical properties of materials based on zirconium(IV) oxide grown by crystallization of ZrO2 melts with 0, 2.0, 2.5, 2.8, and 3.7 mol % of Y2O3 are studied. Using Raman spectroscopy, it is found that this material with the Y2O3 concentration below 2 mol % is mainly a monoclinic ZrO2 phase. The photoluminescence spectra of these crystals contain a blue–green band peaking at an energy of 2.4 eV. This fact in combination with the specific features of the refractive index and absorption coefficient dispersions indicates the presence of high concentrations of oxygen vacancies and polyvacancies in the samples. At higher concentrations of Y2O3 in the mixture, the tetragonal ZrO2 modification becomes dominant in the materials under study and the blue–green luminescence intensity decreases. The experimental optical spectra are analyzed in comparison with the ab initio calculated spectra for ideal ZrO2 crystals in the cubic, tetragonal, and monoclinic phases.

Методами спектральной эллипсометрии, спектрофотометрии и спектроэлектрохимии исследованы оптические и электрохромные свойства тонких пленок, полученных методом центрифугирования из растворов, содержащих амбиполярные полиимиды с пендантными группами на основе 9H-тиоксантен-9-она и его S-диоксидного производного. Показано, что спектральные зависимости показателя преломления и коэффициента поглощения, а также электрохромные свойства тонких пленок полиимидов в условиях электрохимического восстановления и окисления сильно зависят от типа пендантной группы. На основании оценок ширины запрещенной зоны сделан вывод о возможном перспективном использовании тонких пленок полиимидов в качестве рабочих слоев в мемристорах нового типа. Ключевые слова: мемристоры, диэлектрические пленки, амбиполярные полиимиды, эллипсометрия, электрохромизм.

Early diagnosis of pre-cancer and early stages of colorectal cancer (CRC) is the key to a long-term survival of patients, decreasing their invalidity rate, and reduction of therapy costs. This study aims to define the list of fatty acids (FA) of erythrocyte (Er) membranes and blood serum (BS) which could serve as biomarkers of pre-cancer (adenomatous polyps), and of early stages of CRC, depending on tumor localization. 65 patients with CRC of stage 1-2 (63.2±9.4 years), 25 patients with adenomatous polyps, 35 conditionally healthy subjects were included in the study. Studies of the composition of FAs of Er and BS were conducted with the help of the Agilent 7000B (USA) LC/MS system based on three quadrupoles. The levels of 50 FA in BS of Er were defined. Upon completion of standardization the diagnostic panel, comprising С16:1;7, C18:2 n-6, С15:0, omega-6/omega-3, C18:0, С14:0, C18:1;t9, C20:0, C12:0, C17:0, the ratio of saturated/unsaturated FA, enabled to discern the patients with adenomatous polyps from healthy subjects with AUC 0.883, specificity of 0.89, sensitivity of 0.81. The key role in differentiation of patients with 1-2 stage of CRC from the healthy belongs to omega-3 PUFA, especially С22:6n3, the total content of С20:5 n3 and С22:6 n3, as well as the sum of all omega-3 PUFA both in the Er and BS. Their increase prevails over the increase of omega-6 PUFA (С20:2 n6, С22:3 n6, С22:4 n6), especially in BS. Only in BS we revealed the highly significant increase of С20:4 n6 (p < 0,00003) in patients with CRC as compared to healthy subjects. The model, comprising the levels of the following FAs, i.e.С14:0, С15:0, С16:1;7, С18:3 n-3, C20:2 n-6, C20:3 n-6, C20:5 n-3, C22:4 n-6, C22:5 n-3, C22:6 n-3, the sum of omega-3, omega-3 (EPA+DHA), the ratio of saturated/polyunsaturated FA, secured AUC equal to 0.916 with specificity of 0.90, sensitivity of 0.95 upon differentiation of patients with 1-2 CRC stage from healthy subjects. Erythrocyte levels of С18:3 n-3, С14:0, С15:0, С20:2 n-6 and the ones of BS (С18:3 n-3, 22:6 n-3), which tended to be higher in cases of proximal tumors as compared to the distal ones (p=0.05-0.00007), became significant in differentiation of localization of early CRC. The panel, consisting of C18:2 n-6, the sum of omega-6, C18:0, the sum of PUFA, C20:4 n-6, the ration if saturated/polyunsaturated FA, saturated/unsaturated FA, С16:1;7, C20:2 n-6, C20:3 n-6, С15:0, C22:4 n-6, C20:0, C12:0, C22:6 n-3, С18:3 n-3, enable to achieve AUC, equal to 0.824, with specificity of 0.82, sensitivity of 0.86 upon differentiation of patients with adenomatous polyps from the ones with 1-2 stage of CRC. The levels of FA of Er membranes and BS proved to be highly significant when applied as biomarkers used in diagnosis of the pre-cancer and early cancer stage, taking into account localization of the tumor. Application of these markers in clinical practice within the course of screening and modern diagnosis will serve as a perspective trend and will result in a decrease in incidence of cases and mortality rate induced by CRC.

Abstract The purpose is to identify the pathophysiological mechanisms of stroke development in patients with COVID-19. Methods A total of 92 patients (46.72+1.72 years) with impairments of cerebral circulation due to COVID-19 (confirmed by positive PCR test results) had been examined. Among them, 67 patients had an ischemic stroke, 14–a transient ischaemic attack, 11–an intracerebral hemorrhage, 3– a subarachnoid hemorrhage. The parameters of hemostasis were measured by standard methods, electrical and viscoelastic parameters of red blood cells (RBC) by the dielectrophoresis method was carried out. Results Most of the surveyed persons (60 patients) showed signs of an intravascular coagulation and thrombosis: accelerated platelet-leukocyte aggregation, increased levels of coagulation products, reduced fibrinolysis activity (p=0.002–0.04). The levels of D-dimer, fibrinogen, ESR, platelet count were significantly higher in this group compared to patients in the second one (p<0.01). A moderate increase in summarized rigidity, viscosity of RBC was noted. The level of RBC hemolysis was associated with platelet count (r=0.727, p<0.05), D-dimer level (r=0.422, p=0.04), and fibrinogen level (r=0.318, p<0.05). In the second group of patients (32 persons with a predominance of men - 25 male subjects), the markers of thrombosis had moderate deviations. A sharply reduced RBC deformability with increased summarized rigidity and viscosity was dominant coupled with the background of high electrical conductivity of cell membranes compared to the indicators in the first group (p<0.01). There was a decrease in membrane capacity, surface charge, electrical dipole moment of the cells and polarizability at all frequencies of the electric field than those in the first group (p=0.0001–0.05). A sharp decrease in RBC deformability creates obstacles to overcoming small-diameter capillaries, leading to violations of microcirculatory blood flow. The RBC deformability was associated with levels of ferritin (r=0.407, p=0.024), HbA1c (r=0.419, p=0.033), uric acid (r=−0.303, p<0.05), and LDL cholesterol (r=0.426, p=0.029). Incubation of blood samples in vitro for 10 min with riboflavin, nicotinamide, inosine, which ensures RBC energy metabolism (anaerobic glycolysis and pentose phosphate pathway) restored the reduced the RBC deformability (p<0.01), and decreased the RBC aggregation (p<0.001). Similar changes were obtained when coenzymes were administered to patients in vivo. Conclusion Two independent mechanisms of cerebral circulatory disturbances have been identified in COVID-19 stroke patients: both thrombotic and hemorheologic. The thrombotic variant is associated with a procoagulant state and with an activity of inflammation. The hemorheologic variant is caused by a decrease in the activity of the RBC energy metabolism enzymes; it is associated with the presence of metabolic disorders and is to be eliminated by an administration of coenzymes and metabolites. Funding Acknowledgement Type of funding sources: Other. Main funding source(s): This research was done within the framework of the topic “Epidemiological monitoring of the population state of health and studies on molecular genetic and molecular biological mechanisms of the development of common internal diseases in Siberia for improvement of the relevant diagnostic, preventive, and therapeutic methods” in State Assignment No. 0324-2018-0001, registration No. AAAA-A17-117112850280-2

The SiCOH low-k dielectric film was grown on Si substrate using plasma enhanced chemical vapor deposition method. Atomic structure and optical properties of the film were studied with the use of X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) absorption spectroscopy, Raman spectroscopy and ellipsometry. Analysis of XPS data showed that the low-k dielectric film consists of Si-O4 bonds (83%) and Si-SiO3 bonds (17%). In FTIR spectra some red-shift of Si-O-Si valence (stretching) vibration mode frequency was observed in the low-k dielectric film compared with the frequency of this mode in thermally grown SiO2 film. The peaks related to absorbance by C-H bonds were observed in FTIR spectrum. According to Raman spectroscopy data, the film contained local Si-Si bonds and also C-C bonds in the s-p3 and s-p2 hybridized forms. Scanning laser ellipsometry data show that the film is quite homogeneous, homogeneity of thickness is ~ 2.5%, and homogeneity of refractive index is ~ 2%. According to analysis of spectral ellipsometry data, the film is porous (porosity is about 24%) and contains clusters of amorphous carbon (~ 7%).

Aim of work is to study the compositional features of fatty acids (FA) of erythrocyte membranes in patients with diff erent localization of the tumor in colorectal cancer (CRC). Materials and methods . Using a chromatography-mass spectrometric system (GC/MS) Agilent 7000B based on three quadrupoles (USA), the composition of erythrocyte (Er) membranes of 129 patients with CRC was studied: (average age 63.2±9.4 years, of which 68 men and 61 women; 25 with proximal, 98 with distal tumor localization) and 35 people in the comparison group. Results . A greater degree of decrease in the levels of saturated, monounsaturated FAs (MUFAs), and, conversely, an increase in the levels of polyunsaturated FAs (PUFAs) in patients with distal tumor localization compared to healthy ones, was established than the same ratio in the pair “proximal localization of tumor RCC — healthy”. A greater degree of increase in the level of omega-3 PUFAs was noted than omega-6, which aff ected the ratio n-6 / n-3, which was signifi cantly reduced in cancer patients, to a greater extent with distal tumor localization. The most signifi cant for distinguishing tumors located in diff erent parts of the intestine were: saturated fatty acids — myristic C14:0 (p<0,001) and pentadecanoic C15:0 (p=0,012), omega-3 a-linolenic (C18:3; n-3) (p=0,02), whose levels were signifi cantly higher and, conversely, most of the omega-6 PUFAs (C18:2 n-6, C20:3 n-6, C20:4 n-6) and one omega-3 PUFAs — C22:6 n-3 (p<0,05), whose levels were signifi cantly lower with proximal localization of the tumor than with distal. Conclusion . The results obtained indicate the importance of taking into account the localization of the tumor in patients with CRC when conducti ng studies of metabolic profiles.

The luminescent and optical properties of materials based on zirconium oxide obtained by the crystallization of ZrO2 with 0, 2.0, 2.5, 2.8, and 3.7% mol Y2O3 melts were studied. Using Raman spectroscopy, it was found that when the Y2O3 content in the mixture is less than 2 % mol. the material is predominantly a monoclinic ZrO2 structure. For such crystal, a blue-green band with the maximum energy of 2.4 eV was observed in the photoluminescence spectra. This fact, together with the peculiarities of the refractive index and absorption dispersion spectra, indicates the presence of a high concentration of oxygen vacancies and polyvacancies in the sample. With a higher content of Y2O3 in the mixture, the tetragonal modification of ZrO2 dominates in the studied materials; the intensity of blue-green luminescence decreases. A comparative analysis of experimental optical spectra with the first-principle calculations for ideal ZrO2 crystals in the cubic, tetragonal and monoclinic phases was performed.