Contact Part Research Articles

A study on the effect of platelet-rich plasma (PRP) to promote bone fusion in lateral interbody fusion of the lumbar spine using artificial bone

BackgroundLateral lumbar interbody fusion (LLIF) via a retroperitoneum approach has gained popularity due to minimal invasiveness, which avoids resection of the spinous process and laminae. However, as challenges in grafting autogenous bone persist, artificial bone has been tested in Japan to fill the spinal cage. Platelet-rich plasma (PRP) contains growth factors and anti-inflammatory cytokines to promote cellular proliferation and repair damaged tissues. While the effects of PRP on tendon and ligament repair are widely known, any effects on bone healing are scarcely reported. However, PRP-loaded artificial bone carries potential to improve intervertebral bone fusion.ObjectiveThis study assessed whether PRP enhances intervertebral bone fusion in LLIF surgery using β-tricalcium phosphate artificial bone.MethodsThe current study was a prospective, randomized, controlled trial. We evaluated 13 consecutive patients undergoing LLIF surgery in our hospital. Patients received artificial bone impregnated with PRP or without PRP within the same fusion cage. The primary outcome was the intervertebral bone fusion rate at 6 and 12 months postoperatively, evaluated using CT imaging. The intervertebral bone fusion rates with and without PRP loading and with and without contact part between the endplate and the artificial bone were compared. Secondary outcomes included clinical evaluations using visual analog scale scores for low back pain, buttock-leg pain, and leg numbness from the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOA-BPEQ) and the Oswestry Disability Index (ODI), plus adverse events information.ResultsOf the 13 patients (29 vertebral segments) included, bone fusion was observed in 43.4% of the PRP group and 26.1% of the non-PRP group at 6 months (p = 0.216). At 12 months, fusion rates were 60.9% with PRP and 34.8% without PRP (p = 0.074). The fusion rate was significantly higher in cases with good contact between the vertebral endplate and the artificial bone (p = 0.0004). Clinical scores improved postoperatively. Adverse events were in accordance with expectations from LLIF surgery and no PRP-specific events occurred.ConclusionPRP did not significantly improve intervertebral bone fusion rates in LLIF surgeries, particularly in cases with poor contact between the vertebral endplate and artificial bone. While PRP may have a limited role in enhancing bone fusion, maintaining good contact between the vertebral endplate and artificial bone is crucial for successful outcomes. Further research is needed to explore optimal uses of PRP in spinal fusion surgeries.

Design and experiment of bionic skateboard for rice direct seeding machine based on loach body surface

Aiming at the problem of heavy adhesion and large resistance of the rice direct seeding machine slide in the disturbed saturated paddy field environment, the non-smooth surface of the loach body was observed by microscopic observation; the simulation analysis was carried out using Fluent software, revealing the principle of reducing adhesion and drag of the non-smooth surface; the Box-Behnken response surface method was used to design the experiment, and the regression equation of the total resistance of the groove non-smooth surface FBand the groove width w, groove depth hand incoming flow velocity was obtained. vThe optimization analysis results show that when wis 4 mm、v1.25 m/s, 4.5 mm、hthe maximum drag reduction rate reaches 10.052%; based on the optimal parameters, the rice direct seeding machine bionic slide was trial-produced, and the indoor paddy field soil trough test was carried out, and the final drag reduction rate reached 10.23%. This study can provide new ideas for the development of adhesion and drag reduction technology for paddy field soil contact parts.

A de Sitter S-matrix from amputated cosmological correlators

Extending scattering to states with unphysical mass values (particles “off their mass shell”) has been instrumental in developing modern amplitude technology for Minkowski spacetime. Here, we study the off-shell correlators which underpin the recently proposed S-matrix for scattering on de Sitter spacetime. By labelling each particle with both a spatial momentum and an independent “energy” variable (the de Sitter analogue of a 4-momentum), we find that the practical computation of these correlators is greatly simplified. This allows us to derive compact expressions for all 3- and 4-particle S-matrices at tree-level for scalar fields coupled through any derivative interactions. As on Minkowski, we find that the 3-particle and exchange part of the 4-particle S-matrices are unique (up to crossing). The remaining contact part of the 4-particle S-matrix is an analytic function of just two differential operators, which become the usual Mandelstam variables in the Minkowski limit. Finally, we introduce a spectral decomposition for the tree-level exchange of a heavy field responsible for a cosmological collider signal. Once projected onto physical mass eigenstates, these S-matrix elements encode the statistical properties of the early inflationary perturbations.

Mimosa plant leaf-inspired 180° foldable lithium-ion batteries with enhanced electrochemical-mechanical behaviors

Developing high-performance batteries with flexibility is crucial for flexible electronic applications. Although various types of flexible battery designs have been proposed in recent years to improve cycling performance and flexibilities, their application is limited in the most widely used flexible device, namely foldable screen smartphones, due to their inability of 180° folding. Here, inspired by the unique dynamic property of the mimosa plant leaf, we design a bio-inspired flexible lithium-ion battery (FLIB) containing thick energy-storage modules, analogous to the leaflets, and electrical contact part, analogous to the leaf stalk. This design resulted in a FLIB with high flexibility (180° folding and bending), cycling stability, and scalability. Notably, our FLIB demonstrated an improved cycling performance, even under harsh dynamic deformations (10,000-times dynamic 180° folding and 7500-times dynamic bending). The potential mechanisms of mechanical protection for the FLIB were investigated through finite element analysis, further proving its remarkable mechanical endurance. Therefore, our flexible battery design meets the demand of flexible devices for stable power supply under various deformation states. This work sheds new light on the structural innovations and practicality of flexible batteries for future applications.

Variational inequality for a Timoshenko plate contacting at the boundary with an inclined obstacle.

A class of variational inequalities describing the equilibrium of elastic Timoshenko plates whose boundary is in contact with the side surface of an inclined obstacle is considered. At the plate boundary, mixed conditions of Dirichlet type and a non-penetration condition of inequality type are imposed on displacements in the mid-plane. The novelty consists of modelling oblique interaction with the inclined obstacle which takes into account shear deformation and rotation of transverse cross-sections in the plate. For proposed problems of equilibrium of the plate contacting the inclined obstacle, the unique solvability of the corresponding variational inequality is proved. Under the assumption that the variational solution is smooth enough, optimality conditions are obtained in the form of equilibrium equations and relations revealing the mechanical properties of integrated stresses, moments and generalized displacements on the contact part of the boundary. Accounting for complementarity type conditions owing to the contact of the plate with the inclined obstacle, a primal-dual variational formulation of the obstacle problem is derived. A semi-smooth Newton method based on a generalized gradient is constructed and performed as a primal-dual active-set algorithm. It is advantageous for efficient numerical solution of the problem, provided by a super-linear estimate for the corresponding iterates in function spaces. This article is part of the theme issue 'Non-smooth variational problems with applications in mechanics'.

20kV Cubicle Maintenance at PT PLN (Persero) APJ Banten Utara Rayon Prima Krakatau

The disturbances that often occur in 20kV cubicles are those with low insulation resistance values ​​caused by several factors such as environmental conditions, humidity levels, dust, temperature, water, pressure disturbances and other disturbances. If this disturbance is left unchecked, it can cause short circuits and electric current leaks. Another disturbance that is often experienced by 20kV cubicles is corona, where this disturbance causes a hissing sound in the cubicle and the appearance of rust on the indoor contact parts of the cubicle. If this condition occurs continuously it can cause serious damage to all 20kV cubicle components and cause losses for customers and PT. PLN (Persero). So to anticipate these problems, maintenance is required on 20kV cubicles. PT. PLN (Persero) carries out annual maintenance of 20kV cubicles to increase the insulation resistance value and overcome the problems of hissing and rust caused by corona events. This Industrial Practice assignment discusses the maintenance of 20kV cubicles in accordance with PT's SOP. PLN (Persero). After carrying out maintenance on the 20kV cubicle, the problems that occur can be resolved, such as increasing the insulation resistance value and the disappearance of the hissing sound and rust on the contacts of the 20kV cubicle.

An efficient method for solving electrical constriction resistance of rough surfaces

An efficient method is presented to solve the electrical constriction resistance (ECR) in electrical contact problem. For two contact parts under a specified total current, the conjugate gradient algorithm is proposed to determine the unknown current density in contact region. Two variations of discrete convolution-fast Fourier transform algorithm are used to solve the electrical potential for contact parts of finite and infinite size, then the ECR can be obtained. These algorithms lead to an efficient method, which is verified by finite element analysis and analytical formulas. Compared with widely used methods for estimating ECR, the present method shows broad applicability in diverse surfaces by considering both shapes and interactions of contact spots, and has capacity to capture the solution details.

Analysis of the melting process of carbon-bearing pellets in iron bath, slag bath and graphite crucible

Background With the increase in the amount of scrap steel in society, the proportion of electric furnace steelmaking is increasing year by year, especially in China. Due to the high Zn content, the electric furnace arc dust (EAFD) needs to be recovered by non-blast furnace process. Due to EAFD containing a large amount of zinc ferrite, it needs to be recovered by fire process. It is a promising process to melt the EAFD pellets to get the discount and zinc-rich secondary ash. Methods To clarify the melting behavior of pellets in the metallurgical process, the slag phase diagram and the effect of temperature and FeO on slag viscosity were calculated using FactSage, and the melting process of electric furnace arc dust (EAFD) pellets in a graphite crucible, iron bath, and slag bath were experimentally investigated. Results The experimental results show that the viscosity of the slag system decreases with increasing temperature and FeO content, and the effect of FeO on viscosity is greater. The viscosity decreased from 0.305 to 0.276 Pa·s when the FeO content in the slag was increased from 0 wt. % to 2 wt.% at 1773 K. The melting process of the EAFD pellets in an iron bath and graphite crucible was consistent, and after the formation of liquid-phase slag in the pellets, the liquid-phase slag was diffused to melt the pellets. Conclusions The iron bath improved the heat transfer conditions of the pellets, reducing the smelting time from 600 to 360 s. The slag bath promoted the slagging reaction of the contact part to change the pellet melting process and increase the pellet melting speed, and the EAFD pellets melted within 240 s in a slag bath.

A thermo-mechanical numerical method for modelling heating due to frictional sliding

Heating due to frictional sliding is an important phenomenon in tribological applications. The present study develops a numerical method based on the finite elements (FE) for modelling frictional sliding induced heating. More specifically, the method is designed for applications where the behavior of the tool part of the frictional contact couple is not critical so that it can be idealized as a rigid body. The contact between the tool and the target, assuming linear elastic material, is modelled with the penalty method. The FE-discretized balance of linear momentum is time discretized with the Newmark scheme, and the FE-discretized heat equation is time discretized with the backward Euler scheme. The global coupled thermo-mechanical problem is solved with a globally iterative staggered approach. The frictional contact model is verified against analytical solution of a rotating blade pressed against a plane. Finally, a validation simulation of a pin-on-disc tribology test is carried out.

Optimisation of reduction for prolapsed silicone tube after lacrimal intubation.

A common complication of bicanalicular intubation is dislocation of the silicone tube. Eleven patients with prolapsed silicone tubes who had undergone bicanalicular nasal intubation were injected with a 2 per cent lidocaine solution to infiltrate the lacrimal duct mucosa. A memory wire probe was used to pull a 4-0 suture through the lacrimal passage retrogradely, allowing the suture to grab the silicone tube. Paraffin oil was applied to the contact part of the rope and the silicone tube, then the distal end of the silk thread was removed from the nostril until the tube was pulled into place. The prolapsed silicone tubes were restored by surgery in nine patients, with the drainage tube in the correct position in the eye and the lacrimal duct irrigation unobstructed. The optimisations made in this study are considered effective adjustments of reduction surgery for a prolapsed silicone tube.

Socioeconomic inequalities in uptake of HIV testing during antenatal care: evidence from Sub-Saharan Africa

BackgroundMeasuring socioeconomic inequalities in healthcare usage represents a critical step towards promoting health equity, in alignment with the principles of universal health coverage and the United Nations’ Sustainable Development Goals. In this study, we assessed the socioeconomic inequalities in HIV testing during antenatal care (ANC) in sub-Saharan Africa.MethodsSub-Saharan Africa was the focus of this study. Benin, Burundi, Cameroon, Ethiopia, Gambia, Guinea, Liberia, Malawi, Mali, Mauritania, Mozambique, Rwanda, Sierra Leone, Uganda, Zambia, and Zimbabwe were the countries included in the study. This study used current Demographic and Health Surveys data spanning from 2015 to 2022. A total of 70,028 women who tested for HIV as part of antenatal contacts formed the sample for analysis. We utilized the standard concentration index and curve to understand the socioeconomic inequalities in HIV testing during antenatal care among women. Additionally, a decomposition analysis of the concentration index was ran to ascertain the contributions of each factor to the inequality.ResultsOverall, 73.9% of women in sub-Saharan Africa tested for HIV during ANC. The countries with the highest proportions were Malawi, Rwanda, Zambia, and Zimbabwe. Mali Benin, Guinea, Mali, and Mauritania were the countries with the lowest proportions of HIV testing. Being among the richer [AOR 1.10, 95% CI: 1.02,1.18] and richest [AOR 1.41, 95% CI:1.30, 1.54] wealth quintiles increased the odds of HIV testing during ANC. The concentration value of 0.03 and the curve show that HIV testing is more concentrated among women in the highest wealth quintile. Hence, wealthy women are advantaged in terms of HIV testing. As the model’s residual value is negative (-0.057), the model overestimates the level of inequality in the outcome variable (HIV during ANC), which means that the model’s explanatory factors can account for higher concentration than is the case.ConclusionWe found that there is substantial wealth index-related inequalities in HIV testing, with women of the poorest wealth index disadvantaged in relation to the HIV testing. This emphasizes the necessity for sub-Saharan Africa public health programs to think about concentrating their limited resources on focused initiatives to grasp women from these socioeconomic circumstances. To increase women’s access to HIV testing, maternal and child health programs in sub-Saharan Africa should attempt to minimize female illiteracy and poverty. Consequently, health education may be required to provide women with comprehensive HIV knowledge and decrease the number of lost opportunities for women to get tested for HIV. Given the link between knowledge of HIV and HIV testing, it is important to focus on community education and sensitization about HIV and the need to know one’s status.

Research on the Morphology of the Working Surfaces of Contacts Used in Starters in the Agro-Industrial Sector.

The operational suitability of electromagnetic starters equipped with experimental contacts has been substantiated within their use in electrical installations of the agro-industrial sector, which may be affected by the environments containing aggressive components. Tests on commutation wear resistance and investigations on arc erosion of the series-produced contact parts of such starters as PML-1100O4, PML-2100O4 (versions A and B; contact material-CpH-90, CpM-0,2 + M1, KMK-A10m, respectively) and PML-1100O4 starter with the experimental copper-based contact parts (Cu + Nb + Zr + Y2O3; Cu + Mo + MoO3 + C + Ni; Cu + Cr + TiB2 + Nb + C + Zr) have been conducted. The influence of energy parameters of a commutated circuit on the value of electro-erosion wear, the morphology of the working surfaces of contacts and contact resistance have been determined. Investigation results have been obtained by conducting a set of tests on electromagnetic starters at the experimental plant that simulates the operating conditions of the AC-3 application category. The impact of the electric arc of alternative current on the arc erosion of silver-based and copper-based contact materials have been determined by using a scanning electron microscope Cambridge Stereoscan S4-10 equipped with an attachment for X-ray spectroscopic analysis, Link System-290 and an X-ray microanalyzer Camebax SX-50 (CAMECA, Gennevilliers, France). A metallographic analysis of the contact surfaces has been conducted, which contributed to the determination of the patterns of erosive destruction of bridging contacts based on Ag and Cu. Evolution of the eroded morphology of contacts and the surface components of electrical contacts under the influence of an arc have been characterized. In addition, contact mass loss and the dependence of contact resistance have been studied. When manufacturing the experimental contacts, it is possible to abandon the use of silver, which is significantly cost saving, and not to use dangerous contact additives that are hazardous to the environment and people's health.

Friction and wear of current-transmitting contact elements of electric transport with the use of metal-graphite composite materials

The work provides an analysis of research devoted to the problem of manufacturing and operation of current-transmitting elements of electric transport, namely, the durability of contact parts according to operational and tribological characteristics. The work of current-transmitting elements of electric transport consists in the continuous sliding of one element on the surface of another and is accompanied by wear. At the same time, two types of wear are distinguished: mechanical and electrical. It has been established that the correct choice of materials has the greatest impact on reducing friction and wear of electrical contact elements. The basis for this is graphite material, which has the best current-conducting characteristics, but has insufficient strength and wear resistance. Approaches to the creation of materials for electrical contact elements using composite metallographite materials based on copper, aluminum, lead and other materials are analyzed.

Determining the parameters of the dynamic magnetic hysteresis loop of the structural materials by attachable primary transducers

Coercive force, which is one of the structure-sensitive characteristics of ferromagnetic materials, is most often used for magnetic analysis. This approach requires the use of powerful magnetization systems, which leads to an increase in the size of the attachable magnetic probe and, accordingly, to a decrease in the locality of control. The above-mentioned disadvantages can be eliminated by using the parameters of the dynamic magnetic hysteresis loop (MHL), which involves the use of variable magnetic fields. A device for studying the dynamic MHL during cyclic remagnetization for the tasks of testing ferromagnetic materials, namely structural analysis, is proposed. The device consists of a generator of sinusoidal signals, an amplifier, a cur¬rent sensor, an attachable magnetic probe, a two-channel analog-to-digital converter (ADC), and a computer. The attachable magnetic probe is proposed in the form of a U-shaped core with magnetization windings on one leg and measurement winding on the other leg. The signal from the generator through the amplifier and the current sensor enters the magnetization winding. The ADC receives two signals: first one – from the measurement winding, and second – from the current sensor. Both signals from the ADC output in digital form are processed and analyzed by the computer using the developed specialized software in the LabVIEW language. Due to the developed software the filtering and integration of the signal from the measuring winding as well as the MHL plotting and MHL parameters calculation was realized. To reduce interference when determining MHL parameters, averaging over 50 magnetization cycles was performed. The attachable magnetic probe with the dimensions of the contact part 30x17 mm created a field with a strength of 300 A/m at a frequency of 50 Hz. The device was tested on specimens of sheet steel of 09G2S type with a thickness of 4 mm, in which uniaxial tensile stresses were created. The obtained results show the sensitivity of the dynamic MHL area to mechanical tensile stresses, as it increases from 14.8 to 16.8 mT A/m during loading.

The CanMEDS Competency Framework in laboratory medicine: a phenomenographic study exploring how professional roles are applied outside the clinical environment.

The CanMEDS Competency Framework is an internationally recognized model used to outline the proficiencies of a physician. It has predominantly been studied in clinical environments but not all medical specialties take part in direct patient contact. In laboratory medicine, the role of the physician is to promote and enhance patient diagnostics by managing and overseeing the functions of a diagnostic laboratory. This phenomenographic study explores the lived experiences of biochemistry, microbiology, and pathology residency program directors to better understand how they utilize the CanMEDS competencies. Eight laboratory medicine program directors from across Canada were individually interviewed using a semi-structured interview, and the data was analysed using inductive thematic analysis. The findings show that the current framework is disconnected from the unique context of laboratory medicine with some competencies appearing unrelatable using the current standardized definitions and expectations. Nevertheless, participants considered the framework to be an appropriate blueprint of the competencies necessary for their professional environment, but to make it accessible more autonomy is required to adapt the framework to their needs. Newer renditions of the CanMEDS Competency Framework should better consider the realities of non-clinical disciplines.

Full-field contact dynamic mechanical properties of tread rubber material under rolling and slippery conditions based on digital image correlation

The dynamic mechanical properties of rolling tire on special road surface were closely related to the vehicle’s handling stability, driving safety and braking effectiveness. The tire tread rubber material was the only contact part of the vehicle with the road surface, so the strain distribution characteristics of tread rubber material within the contact patch of rolling tire on thin water film pavement played a crucial role in the mechanical characteristics of vehicle. In this paper, a non-contact tire tread rubber rolling mechanical test system was developed. The improved digital image correlation (DIC) method was used to obtain the full-field strain distribution of tread rubber blocks. The effects of load and velocity on the strain rate of the marked points, the full-field strain distribution in the region of interest and rolling resistance were investigated under thin water film pavement. The experimental results were compared with dry condition to analyze the effect of water film on the rolling dynamic characteristics. The results showed that the strain rate increased first and then fluctuated under the action of thin water film. With the increase of speed and load, the full-field strain distribution of tread rubber contact patch was gradually occupied by low strain zone. The change rate of rolling resistance firstly increased and then decreased with the increase of rotational speed.

Nasal spray of an IgM-like ACE2 fusion protein HH-120 prevents SARS-CoV-2 infection: Two investigator-initiated postexposure prophylaxis trials.

HH-120, an IgM-like angiotensin converting enzyme 2 (ACE2) fusion protein, has been developed as a nasal spray against Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) and is currently undergoing human trials.HH-120 nasal spray was assessed for postexposure prophylaxis (PEP) in two investigator-initiated (NS01 and NS02) trials with different risk levels of SARS-CoV-2 exposure. NS01 enrolled family caregiver participants who had continuous contacts with laboratory-confirmed index cases; NS02 enrolled participants who had general contacts (Part 1) or close contacts (Part 2) with index cases. The primary endpoints were safety and laboratory-confirmed and/or symptomatic SARS-CoV-2 infection.In NS01 trial (14 participants), the SARS-CoV-2 infection rates were 25% in the HH-120 group and 83.3% in the external control group (relative risk reduction [RRR]:70.0%). In NS02-Part 1 (193 participants), the infection rates were 4% (HH-120) versus 11.3% (placebo), symptomatic infection rates were 0.8% versus 3.5%, hence with a RRR of 64.6% and 77.1%, respectively. In Part 2 (76 participants), the infection rates were 17.1% (HH-120) versus 30.4% (placebo), symptomatic infection rates were 7.5% versus 27.3%, with a RRR of 43.8% and 72.5%, respectively. No HH-120-related serious adverse effects were observed.The HH-120 nasal spray used as PEP was safe and effective in preventing laboratory-confirmed and symptomatic SARS-CoV-2 infection.

Application of computer simulation technology in modal analysis of engine mount

In order to obtain the vibration response characteristics of the engine mount, its constrained modal analysis was completed based on the finite element method. The mesh of the contact part between the bolt head and the bracket part was considered as shared node, achieving the simulation of compressive contact between the bolt and bracket parts. The simulation results of natural frequencies and modal shape were verified through constrained modal experiments. The results indicated that the accuracy of the simulation results is high, and the maximum deviation between the natural frequency and the experimental value is less than 5 %. Compared to higher-order modes, the preload had a more significant impact on lower order modes. Based on the modal analysis results, reasonable excitation vibration directions were set, and the dynamic stiffness of the model was simulated and tested within the frequency range of 2400 Hz, providing important basis for optimizing vibration isolation performance.

Design of the water-cooling structure for the 100 kA DC mechanical switch in the CRAFT quench protection system

The DC mechanical switch is connected in series with the superconducting magnet in the quench protection system. As the main switch that carries the magnet current for a long time, the temperature of its conductive unit, especially the contact part, inevitably increases significantly during operation. It is necessary to design a water-cooled structure to control the temperature rise. This article introduces the structural design of the conductive unit of the DC mechanical switch for the Comprehensive Research Facility for Fusion Technology quench protection system and uses a combination of theoretical calculation, thermal-electrical coupling simulation, and Fluent simulation to analyze the thermal stability characteristics at a current level of 100 kA. By comparing and studying the temperature rise characteristics of switches under different cooling paths, diameters of water-cooling pipe, and water flow rates, a design basis is provided for determining a 15 mm diameter “∏” shaped cooling water path structure for the mechanical switch. The DC mechanical switch water-cooled structure designed in this article is expected to effectively control the temperature rise level of the contact.

FINITE ELEMENT ANALYSIS OF THE STRESS-STRAIN STATE OF 3D COMPUTER GENERATED IMAGING OF REVERSE TOTAL SHOULDER ENDOPROSTHESES

Objective. To conduct a finite element analysis of the stress-strain state (STS) of the elements of the shoulder joint after implantation reverse shoulder endoprostheses. Material and methods. After 3Dscanning of the composite model of the scapula and humerus, geometric models of the shoulder joint were built in the SolidWorks 2019 SP 1.0 program, followed by mathematical modeling and FEA. For the comparative analysis of the STS of the «bone – reverse endoprosthesis» s ystem, t hree-dimensional m odels o f two types of reverse shoulder endoprostheses were created, which were then transformed into a finite-element model and implanted into the developed three-dimensional mathematical model of the shoulder joint without cement. The STS calculations of the elements of endoprostheses were carried out for two positions: abduction 90° and flexion 90° with a load of 5 kg. Results. Compared to the healthy shoulder joint, models with reverse shoulder endoprosthesis have significantly different contact stresses and contact areas. It was established that the maximum stress in the details of the contact parts of the endoprosthesis when retracted at an angle of 90° did not exceed +1.78 MPa, when bending +5.8 MPa. The maximum stresses on the liner during shoulder abduction are +8.6 MPa, the minimum –7.38 MPa, during flexion +2.3 MPa and –2.45 MPa, respectively. It has been proven that the contact areas of the hemisphere and inserts of both reverse endoprostheses during abduction and flexion of the limb by 90° are significantly larger (573 mm2 vs. 1809–2081 mm2) when compared with a healthy shoulder joint, while changes in the area between the endoprostheses are insignificant and equal to 2...3 %. Conclusions. Analysis of the STS load of elements of reverse shoulder endoprosthesis showed that the greatest stresses occur in the contact zones. It has been proven that the maximum stresses on the contact structures of endoprostheses are less than on the head of a healthy joint, but the contact area during implantation of a reversible endoprosthesis of the shoulder joint increases significantly (more than 3 times).