This article presents the results of using the analysis of heart rate variability using high-resolution rhythmocardiography for dynamic intraoperative assessment of the state of autonomic regulation of heart rate in patients with thyroid nodules during hemithyroidectomy.

This article presents the results of a survey of individuals with stable angina pectoris of high gradations and heart rate variability in comparison groups.

We consider the features of the dynamics of the wave-packet self-action within the framework of a model described by the one-dimensional discrete nonlinear Schrödinger equation with allowance for the effects of acoustic relaxation of the nonlinear response of the medium. Such models are actively used to describe the energy transfer along protein molecules. Analytical and numerical studies show that the dynamics of the wave packets with energies exceeding the critical values significantly differs from the field evolution in a continuous medium. The behavior of initially smooth (on the scale of the distance between the structural elements of the medium) and initially localized field distributions propagating at subsonic speed is studied in detail. A specific self-action regime, which is not characteristic of the continuous limit, is shown to exist where the wave packet, during its propagation, slows down to a complete stop while undergoing self-compression to the size of the lattice period. Radiation losses increase significantly at the final stage of this process and eventually lead to the formation of a soliton-like structure, which usually moves in the opposite direction (with respect to the initial one). In the case of wave packets with supersonic initial speed, the self-action dynamics develops in a similar way. However, in this case, the motion of the quasisoliton which carries most of the energy becomes subsonic during the backward propagation. As applied to the molecular chains, the considered effects lead to a noticeable increase in the localized action of the compressed excitation on individual structural elements of the discrete medium.

The possibilities of X-ray reflectometry for studying the structure of planar liquid-phase membranes are demonstrated by the example of polyester films formed on the surface of deionized water from solutions of polylactoglycolide (PLG) in chloroform and tetraglycol (TG). It is found that the use of solutions with PLG concentrations ranging from 1 to 4 wt % or above 6 wt % leads to a proportional increase in the density of these films with preservation of their structure and thickness up to 25 Å. At a PLG concentration close to 5 wt % the PLG/TG system transits to an unstable state, characterized by intense penetration of PLG aliphatic chains into the water substrate bulk to a depth up to 100 Å.

Specific features of the self-action of wave fields are studied in the framework of a discrete nonlinear Schrödinger equation (DNSE). It is shown analytically and numerically that the dynamics of wave packets with initially normal group-velocity dispersion in systems described by this model equation may differ significantly from the evolution of similar distributions in a continuous medium. The behavior of wave fields with initially smooth (compared to the lattice period) amplitude profile and phase front is analyzed in detail, and the mechanism of their destruction in chains of equidistant elements is studied. A modification of the dispersionless approximation is proposed, which makes it possible to theoretically describe the effects leading to the development of small-scale instabilities against the background of a smooth envelope and to its subsequent significant deformations (up to destruction). Estimates of critical parameters are presented above which one should expect the above-mentioned processes (uncharacteristic of continuous media).

During surgery or intervention, the current status of the cardiovascular system is of special importance since cardiovascular abnormalities may prove life-threatening due to extreme treatment. Cardiovascular complications during surgery and in the postoperative period require constant supervision of the current cardiovascular status. ECG testing more often indicates events that have already taken place, which were preceded by dysregulatory changes. They can now be diagnosed before, during, and after operation by means of high-resolution rhythmocardiography with the analysis of the wave structure of the heart rhythm, or heart rate variability analysis as a marker of the current cardiovascular status. This paper presents some applications of rhythmocardiography and heart rate variability in percutaneous angioplasty.

We study the specific features of the evolution of spatially confined pulses with a finite amplitude and a duration of several periods of wave field oscillations both analytically and numerically. The initial equation, which describes propagation of a reflectionless ultrashort pulse, is transformed to a nonautonomous modified Korteveg-de-Vries equation after passing over to self-similar variables. In this simpler equation for the self-similar function, the dynamics of the internal structure of the wave field is determined by the competition of “dispersion” and cubic nonlinearity only. The evolution of pulses in the directions of the increasing and decreasing nonlinearity is separately considered. Numerical simulation of the problem has demonstrated that: i) the energy center of the wave packet moves nonuniformly along the propagation path, ii) a dispersion shock wave consisting of a set of solitons is excited in the rear part of a pulse propagating in the direction of increasing nonlinearity in the process of the dispersion spreading, and iii) the evolution of the pulses propagating in the direction of decreasing nonlinearity is also accompanied by excitation of a breather soliton.

Introduction. The work is devoted to the estimation of students' opinion on the use in the conditions of the current educational practice of the business game technique modified for the practical training on hospital therapy in full-time form in the premises of the university outside the clinical base that excluded the opportunity to work with real patients. Materials and Methods. Twenty-eight 6-year students of the Faculty of Medicine and Prophylaxis participated in the pilot project on the terms of voluntary consent. The students' opinion about the proposed form of the class was evaluated in an anonymous questionnaire using the Internet platform Google Forms. In the course of the class, each student consistently acted in the role of a patient, a doctor, and an insurance company expert in parsing a clinical situation formed on the basis of the assessment fund and universal instructions for a standard patient. The feedback forms allowed to objectivize the estimations of the necessary competences mastering and to reveal the main problems in mastering of communication skills, examination, medical triage and making of evidence-based clinical decisions, conditioned by the forced transition to the distance learning format, as well as to define the volume and the list of the corrective measures aimed to increase the quality of medical university graduates training. Results and Discussion. Respondents positively evaluated the proposed form of practical training in the inaccessibility of patient contact. However, they noted significant difficulties in performing both the role of a standardized patient and that of a physician or insurance company expert. Conclusion. The urgent pilot testing of the model of full-time practical training based on the "standardized patient" technology and the business game "patient-doctor-expert of an insurance company" allowed the trainees to realize the main problems in mastering the skills of communication, examination, medical triage and making evidence-based clinical decisions caused by the forced transition to a distance learning format. The results obtained will allow us to determine the scope and list of corrective measures aimed at improving the quality of medical university graduates' training.

Associations of phenotypic signs of undifferentiated connective tissue dysplasia (UCTD) and bone fractures not related to postmenopausal, senile or glucocorticoid osteoporosis are discussed. A cross-sectional study enrolled 458 persons (143 had a history of fractures). A significant predominance of individuals with fractures in the UCTD group was revealed. Strong positive correlations of the total number of fractures with the number of external signs of UCTD (p<0.0001), internal signs of UCTD (p<0.0001), Beighton joints hypermobility index (p<0.0001) were found. Weak positive correlations of the number of fractures with the height (p=0.02) and arms span (p=0.011), and the personal smoker index (p=0.01) were revealed.

— A device has been developed to study the physicochemical processes of the formation of a structure that occurs during temperature-induced aggregate transitions of liquid and gel compositions during three-dimensional printing under conditions of significant temperature gradients. The device is based on a three-dimensional coordinate system with a heated pneumatic dispenser of viscous fluid compositions and a substrate cooled to −190°C. Liquid nitrogen, solid carbon dioxide, or an integrated Peltier cooling system are used to cool the substrate. The device is equipped for contact temperature control and has a digital video camera.

Reconstruction of the damaged or missed organs or skeleton fragments is an ambitious target for regenerative medicine. Tissue engineering construction (TEC) comprising three-dimensional bioresorbable scaffold and living cells can become native tissue substitute. Scaffold should correspond to strict requirements. Generally, its physical-mechanical and biochemical characteristics should be comparable with tissue to be replaced. Besides, resorption rate of scaffold material should correlate with the tissue regeneration rate in each case. Thus, the effect of scaffold manufacturing methods on its properties is an important point in TEC design and fabrication. At present study, thermo-extrusion 3D printing of bioresorbable scaffolds based on polycaprolactone and its copolymer with polyethylene glycol and methylphosphate groups, synthesized by novel chemical route, was investigated. Scaffold surface morphology and its internal structures were studied by optical and scanning electron microscopy. The effect of thermal-induced degradation on polymers properties at various 3D printing processing parameters was analysed by gel-permeation chromatography, differential scanning calorimetry and mechanical testing. It was shown that optimizing experimental parameters the developed methods of thermo-extrusion 3D printing enable effective polymer scaffolds fabrication in accordance with their 3D computer model without significant changes of physicochemical properties of initial materials.

We report on the observation of terahertz (THz) signal during the femtosecond laser ablation of metals. Strong correlation between the regimes of ablation and THz generation was found for different metals (copper, zinc, nickel and others). According to previous results, the interconnection of these two effects is caused by their thermal nature.

Using the discrete nonlinear Schrödinger equation, we study the laser radiation self-action dynamics in a nanostructured waveguide system. It is shown that for a laser pulse energy exceeding the critical value, the nonlinear evolution of the wave field markedly differs from the corresponding process in a continuous medium. While the pulse propagates in a discrete medium, its length decreases to values comparable to the scale of the structure and the velocity decreases to zero. The system parameters are determined at which the wave field after the laser pulse termination begins to propagate in the opposite direction in a compressed form. The process of slowing down and stopping the pulse is accompanied by strong radiation losses, so that about a third of the energy of the initial field distribution remains in the final compressed state.

Abstract—An apparatus for selective laser sintering of micron and submicron fraction powders is described. The apparatus allows studies with small volumes of polymer powders, as well as aqueous and alcoholic suspensions to refine the sintering process in order to achieve high spatial resolution (on the order of 10 μm). Thin (approximately 20 μm) layers of spherical microparticles of polymethylmethacrylate (PMMA) with an average diameter of 0.5 to 3 μm were formed. Optimization of the parameters of selective laser sintering and stepwise formation of single layers of PMMA allowed us to obtain 3D structures with a resolution of less than 100 μm.

4 ФБУН «Екатеринбургский медицинский научный центр профилактики и охраны здоровья рабочих промышленных предприятий», Екатеринбург Автономная кардиальная нейропатия (АКН) играет значимую роль в отношении смертности и сердечнососудистой заболеваемости пациентов с сахарным диабетом (СД), актуальным является её своевременное выявление.Цель: оценить на основании анализа показателей ритмокардиографии (РКГ) распространенность АКН, разработать модель прогноза степени её тяжести с оценкой адекватности полученной модели на практике у коморбидных больных СД.Материалы и методы.Включено 310 пациентов (142 мужчины и 168 женщин) с СД возрастом 40,5[26,0;52,0], длительностью 10,0[4;16] и возрастом выявления СД 46,0[34;52,5] лет двух групп: без АКН (n=216) и с АКН (n=94).Критерии исключения: острые и хронические заболевания органов соматической сферы в активной фазе, беременность, прием в день обследования лекарственных препаратов.Изучение вариабельности сердечного ритма (ВСР) методом высокоразрешающей РКГ на КАП-РК-01-«Микор» (рег.уд.№ФС-022б2005/2447-06).Результаты.В группе АКН (n=94) на одного пациента было 8[6;10,5] сопутствующих нозологий против 5[3;9] у пациентов без АКН (n=216), p<0,001.Сравнительный анализ ВСР у пациентов с АКН и без АКН показал, соответственно, с высокой статистической значимостью резкое снижение общей вариабельности SDNN до 12 мс против 24; снижение гуморально-метаболических σl до 8 мс против 16 мс, симпатических σm до 4 мс против 9 мс и парасимпатических волн σs до 3 мс против 11 мс.Разработана и апробирована на новой экзаменационной выборке (СД,n=102) модель АКН и степени ее тяжести с долей правильной классификации 85%, специфичностью 65%, чувствительностью с 100%.Выводы: найдены более выраженные дизрегуляции синусового узла и большая частота коморбидностей у пациентов с АКН, математическая модель определения АКН и степени её тяжести по результатам РКГ показала высокую чувствительность и специфичность.Ключевые слова: сахарный диабет, вариабельность сердечного ритма, автономная кардиальная нейропатия.sympathetic σm(milliseconds) to 4 vs 9 and parasympathetic waves σs(milliseconds) to 3 vs 11.Developed and tested on a new examination sample (DM, n=102) mathematical forecasting model for CAN severity reveled a share of correct classification -85%, specificity-65%, sensitivity-100%.Conclusion: CAN associated with higher frequency of comorbidities in DM patients.mathematical model for determining CAN and it severity according to the results of RCG showed high sensitivity and specificity.

We show theoretically that anisotropy of electronic distribution function inside the laser-irradiated metal leads to the formation of edge currents at the timescale of distribution isotropization. When the electronic pressure in the skin-layer is anisotropic, pressure gradient appears to be non-potential force effectively producing low-frequency magnetic field. In typical experiments with femtosecond laser pumping generated internal magnetic field can rich magnitude up to ~1 Tesla in non-damaging interaction regime. We demonstrate that this field is localized inside the metal, while just a minor part of its energy can be radiated into free space as a sub-terahertz signal.

In order to obtain hydrogel matrices for bone tissue engineering, the process of formation of highly filled alginate-calcium phosphate structures by 3D printing was developed. Optimal conditions for the formation of three-dimensional structures from Ca2+ crosslinked alginate hydrogels and highly filled alginate compositions with fine (5–30 μm) α-tricalcium phosphate (TCP) were determined. Comparative analysis of physicomechanical properties of crosslinked alginate hydrogels showed lower strength and higher elastic modulus of the TCP-filled composite in comparison with pure hydrogel. The difference between the mechanical characteristics of the filled and pure gels increases with the crosslinking density. It was found that, because of the significant content of the mineral dispersed phase, the α-TCP-filled hydrogel does not shrink during crosslinking, unlike pure alginate hydrogel. Using cultures of human umbilical cord mesenchymal stem cells, it was shown in vitro that all the studied samples of both pure and highly filled composite alginate matrices with α-TCP do not have short-term cytotoxic effects.

The article presents the results of a study conducted in patients with connective tissue dysplasia and heart rate variability. The most important signs for making a diagnosis of undifferentiated connective tissue dysplasia are flat feet, Walker-Murdoch wrist sign, alar chest, hypermobility of thumbs, elbows and fingers, and Steinberg thumb sign. Vagal predominance in the heart rate regulation was higher in patients with multiple signs of undifferentiated connective tissue dysplasia. Rhythmocardiography was more useful in identifying the characteristics of heart rate regulation in UCTD patients compared to other noninvasive diagnostic methods.