Pattern Transitions in Unstable Viscous Convective Medium

Convection in a thin layer of liquid (gas) with temperature dependent viscosity between poorly heat conducting boundaries is studied within framework of the Proctor-Sivashinsky model. This model is examined in order to study both the flow pattern formation and the second-order structural phase transitions as between patterns with translational invariance as well as between structures with broken translational invariance but keeping a long-range order. The spatial spectrum of arising patterns and estimation of their visual defectiveness are analyzed. The relation between the density of pattern defects and spectral characteristics of the pattern is found. We also discuss the noise effects on the formation of pattern defects. The influence of temperature dependence of viscosity on the process of pattern formation and structure transformations is also discussed. It is shown that the temperature dependence of viscosity inhibits structural transition from regular rolls to square cells

Treatment of Dupuytren's Contracture at the Present Stage (Literature Review)

Dupuytren disease is widespread among the population of different countries (3 %) and affects the working-age male population to a greater extent.The progressive nature of the course of Dupuytren disease causes a persistent and significant decrease in the functional capabilities of the hands of patients and leads to a limitation of fine and high-precision activity on average in 67 % of patients, and in 3 % causes disability.The problem of treating patients with Dupuytren's contracture remains relevant despite the achievements ofhand surgery. A large number of applied methods speaks of both the urgency of the problem and the possibility of a comprehensive approach to treating patients with this disease at different stages and with varying degrees of severity of contracture of the fingers. Many techniques for treating Dupuytren's contracture and their modifications are described. These are extensive surgical interventions, which involve the complete excision of the palmar aponeurosis, and selective open interventions, which involve the removal of only macro-modified areas - the bundle of the palmar aponeurosis through one large or several small accesses. With the development of minimally invasive techniques, needle-based aponeurotomy methods have spread, which do not imply the removal of pathologically altered tissues, but only relieve tension in the tissue by dissecting it and thereby increase movements in the joints of the fingers. With the development of pharmacology, methods for the enzymatic destruction of the bundle of pathologically altered palmar aponeurosis have appeared.The evolution of approaches to the treatment of Dupuytren's contracture is visible in a gradual transitionfrom complete excision of the palmar aponeurosis to selective techniques, and from them to partial dissections and further to needle and enzymatic methods. However, despite the abundance of methods and good results in treating patients with this pathology, there remains a percentage of relapses, complications and adverse outcomes, the reduction of which is the purpose of developing a modern understanding of this pathology

Theoretical background for the bionic substantiation of parameters of the stubble cultivator working bodies

In the southern regions of Russia, the technology of cultivation of grain crops in the variant of partial sowing has been widely used. In this regard, it became necessary to create effective working bodies of a stubble cultivator that would have fundamentally new resource-saving ways of influencing the area under cultivating and meet the requirements of modern advanced technologies. The shapes of the working bodies surfaces of the cultivators were improved taking into account the mechanic-bionic approach. The main parameters of the toothed cutting surface were determined by the method of bionic comparisons, with a scarab beetle as a bionic prototype. Use of the serrated shape of the cutting edge is consistent with the bionic principle of multi-contact exposure and leads to the fact that the tops of the teeth become stress concentrators and, with a significantly smaller indentation force, cause soil destruction processes, which reduces the energy costs of cutting the soil layer. The optimal curvilinear shape of the working surface made in the form of a logarithmic spiral, is characterized by a constant value of the angle between the normal and the radius vector, and the value of this angle, equal to the angle of internal friction of the soil φ2, will ensure the sliding of the soil and plant residues with minimal energy consumption. The number (n = 4), height (h = 5...7 mm) and tooth placement step (S = 10...12 mm) of the bit tip of the stubble cultivator are analytically justified. The shape of the profile of the working surface of the stubble cultivator bit in the form of a logarithmic spiral with a variable angle of crumbling is proposed. The studies were conducted in the period from September to October 2018 in the soil channel of the research Laboratory of Bionic Agroengineering of the Department of Mechanization and Technical Service in Agro-Industrial Complex. They have shown the decrease in the traction resistance of the proposed working body of the stubble cultivator by 16.5% in comparison with the traction resistance of the serial sample

Rotator cuff tendon ruptures (literature review)

Rotator cuff injury is a common pathology: up to 20 % of the population over 45 years of age has ruptures of varying severity, and up to 40 % of these ruptures are large and massive. The gradual development of tendon degeneration and fatty degeneration of muscle tissue and the asymptomatic course of the disease often lead to late medical attention when secondary arthropathy of the shoulder joint develops. With age, the probability of having a rupture increases, reaching 51 % in people over  80  years of age. The main diagnostic tools are radiography and  magnetic resonance imaging of the shoulder joint combined with clinical examination. Conservative treatment for massive injuries is ineffective, and the risk of worsening rotator cuff tendinopathy to rupture reaches 54 %. There are three main directions in the surgery of rotator cuff injuries: tendon reconstruction or replacement of their defect with grafts; muscle transfer; shoulder arthroplasty. Subacromial balloon spacer and tenogenic patches are also used. Each of these methods has a number of disadvantages and limitations. The frequency of repeated ruptures of reconstructed tendons reaches 45 %. Muscle transfer is extremely demanding on the skill of the surgeon and is associated with high risks of neurological complications. Arthroplasty imposes a number of significant restrictions on the patient, reducing the  quality of life, and prosthesis components wear increases the risk of complications, especially during revision interventions. The use of the subacromial spacer is limited by its high cost and lack of  long-term follow-up of treatment outcomes. Tenogenic patches have not undergone clinical trials, being an experimental technique. There is no single approach to the treatment of massive rotator cuff ruptures. The results are contradictory, the advantages of each of the methods are balanced by their disadvantages, which provides a wide window of opportunity in the studying, optimizing classical and introducing new methods of treatment of this patholog

STATE FUNCTION IN UNSTABLE CONVECTIVE MEDIUM

Convection in a thin layer of liquid (gas) with temperature independent viscosity between poorly heat conducting boundaries is studied within framework of the Proctor-Sivashinsky model. We have shown by numerical simulation of the Proctor-Sivashinsky model that the state with certain topology can be described by the state function, which is the sum of squared mode of temperature spatial spectrum on the surface. The transitions between these states are characterized by splashes in time-derivative of this function and different meta-stable structures, corresponding to different values of the state function have different visually distinguishable topologies

Latissimus Dorsi Transposition in Supraspinatus Tendon Retraction (Patte III) and Thomazeau Grade 3 Fatty Degeneration (Clinical Case)

Introduction. The proportion of injuries of the rotational cuff is from 65 to 84 % of all injuries of the shoulder joint. This pathology is more often registered in people over 60 years old. It is far from always that during initial visits, patients are given the correct diagnosis. Most patients are treated conservatively with short-term improvement or without dynamics. The main diagnostic method is an MRI of the shoulder joint, where we can see soft tissue structures. The proportion of massive rupture of the tendons of the supraspinatus muscle is 10-40 % of all ruptures of the rotator cuff.The more time passes from the moment of injury to surgical treatment, the more pronounced are the retraction and degenerative changes in tendons. A special category is occupied by patients with chronic rupture of the tendon of the supraspinatus muscle with a retraction of more than 5 cm (Patte grade III) and Thomazeau grade 3 fatty degeneration.In this category of patients, it is not possible to re-insert the tendons of the rotational cuff of the shoulder.Objective: to evaluate the clinical effectiveness of surgical treatment of a patient with retinal tendon retraction (Patte grade III) and Thomazeau grade 3 fatty degeneration.Materials and methods. The clinical case is presented: a man with a chronic total rupture of the tendon of the supraspinatus, infraspinatus muscle (Patte grade III) and Thomazeau grade 3 fatty degeneration. Secondary upper subluxation of the head of the humerus is revealed. The patient underwent surgical treatment: transposition of the latissimus dorsi muscle on the large tubercle of the humerus.Results. Six months after the operation, the patient restored the function of the upper limb, pain was stopped. Conclusion. Given the functional result, transposition of the latissimus dorsi tendon can be considered the technique of choice for inoperable tendon rupture of the supraspinatus muscle