Dynamic multifractal characteristics of acoustic emission about composite samples with different stress loading and unloading conditions.

Studying the failure characteristics of the common composite strata structure in western China is essential for evaluating stope stability and predicting coal mine dynamic disasters. To investigate the influence of different stress loading and unloading conditions on the instability characteristics of composite samples, three triaxial loading and unloading test schemes simulating different in-situ mining depths were designed. Complex triaxial tests were conducted on 12 sets of composite samples, and the bearing capacity, acoustic emission (AE) parameters and dynamic multifractal characteristics of the samples under different stress loading or unloading conditions were analyzed. The results indicate that samples tested by stress schemes simulating greater mining depths exhibit less damage, and the failure mode is a tensile-shear mixed failure, but the tensile failure is the main failure mode. The multifractal spectral parameters Δ α of AE time series during the failure of composite samples tested with triaxial loading and unloading schemes simulating different mining depths show a decreasing trend in Δ α values with increasing mining depth, while the change rules of Δ f α values are the opposite. The multifractal parameter changes degree in four-layer rock structure composite samples under different stress conditions are lower than those in three-layer rock structure composite samples, indicating that the microcrack propagation process in the three-layer composite sample is more complex, resulting in higher levels of damage. The dynamic change of multifractal parameters Δ α and Δ f α during different stress loading and unloading stages reflects the influence of axial pressure or confining pressure changes on crack propagation in composite samples. Compared to the initial stress stage, the non-uniformity of AE signals increases in the residual stress stage, and the proportion of large signals becomes more prominent, signifying a complex micro-fracture process in the composite samples.

Electrohydraulic proportional position and pressure loading control utilizing a state perception and processing method.

A new multifunctional proportional control triaxial stress loading apparatus is presented in this study, which can apply an output force on coal rock to simulate the conditions of triaxial stress loading, aiming at solving the problems of excessive consideration of static indices in the design and the incompleteness of the simulation and test verification system for the test parts at the performance analysis stage. This apparatus mainly combines the configuration of a triaxial stress loading system which can meet the stress loading requirements under different operating conditions, with the effective integration of multiple pressure loading operations based on the electrohydraulic proportional control method. In this context, a pressure and position combined control strategy based on the sliding mode is proposed to control the vertical and longitudinal loading hydraulic cylinders. Then, a co-simulation mode including the triaxial stress loading hydraulic system is established to verify the control strategy, system response characteristics and selection of the controller parameters. Furthermore, a multifunctional stress loading experimental platform is developed, and the stress loading characteristics with the proposed strategy are tested and analyzed. The results show that the triaxial stress loading hydraulic system can meet the response characteristics, the fluctuating deviation of the constant loading test can be restricted to 8.5%, the tracking error of the variable loading test is small, the minimum response time of instantaneous loading can reach 2.8 s, and the stress loading effect is noticeable. The experimental platform fully indicates that the stress loading system with the state perception and processing method as the core can meet a variety of verification indices of constant, variable and instantaneous loading tests. This research provides technical support for the smooth, synchronous control and intelligent operation of various types of hydraulic actuator machines.

Pro-Resolving Mediators in Rotator Cuff Disease: How Is the Bursa Involved?

So far, tendon regeneration has mainly been analyzed independent from its adjacent tissues. However, the subacromial bursa in particular appears to influence the local inflammatory milieu in the shoulder. The resolution of local inflammation in the shoulder tissues is essential for tendon regeneration, and specialized pro-resolving mediators (SPMs) play a key role in regulating the resolution of inflammation. Here, we aimed to understand the influence of the bursa on disease-associated processes in neighboring tendon healing. Bursa tissue and bursa-derived cells from patients with intact, moderate and severe rotator cuff disease were investigated for the presence of pro-resolving and inflammatory mediators, as well as their effect on tenocytes and sensitivity to mechanical loading by altering SPM signaling mediators in bursa cells. SPM signal mediators were present in the bursae and altered depending on the severity of rotator cuff disease. SPMs were particularly released from the bursal tissue of patients with rotator cuff disease, and the addition of bursa-released factors to IL-1ß-challenged tenocytes improved tenocyte characteristics. In addition, mechanical loading modulated pro-resolving processes in bursa cells. In particular, pathological high loading (8% strain) increased the expression and secretion of SPM signaling mediators. Overall, this study confirms the importance of bursae in regulating inflammatory processes in adjacent rotator cuff tendons.

Fisioterapia en la rehabilitación del usuario con síndrome doloroso regional complejo / The Physical Therapy in the Rehabilitation of a Patient with Complex Regional Pain Syndrome

Por sus múltiples causas y su sintomatología inespecífica, el síndrome doloroso regional complejo es una de las situaciones clínicas que mayor dificultad genera en el tratamiento fisioterapéutico. Este síndrome se define como una disfunción vasomotora, mediada por el sistema simpático en donde su manifestación primaria es un dolor que aumenta y permanece en el tiempo y que no tolera las diferentes modalidades y técnicas utilizadas por los Fisioterapeutas como herramientas de intervención. A través del tiempo el Fisioterapeuta ha tenido una acción relevante en el manejo del usuario con dolor, sin importar la causa o consecuencia del mismo. Por esta razón con esta revisión se quiere, integrar acciones terapéuticas como la carga de peso, la desensibilización y la relajación, que han dado excelentes resultados, a las prácticas tradicionales (medios físicos, ultrasonido, masaje sedativo y diferentes tipos de corrientes) aplicables a quienes padecen dolor secundario, traumático o visceral que compromete el sistema simpático en forma refleja.

Due to its multiple causes and non-specific symptoms, the complex regional pain syndrome is one of the clinical situations that generates greater difficulty in the physical therapy treatment. It is defined as a vasomotor dysfunction, mediated by the sympathetic nervous system with a pain that grows and lingers over time and which does not tolerate the different modalities and techniques used by physical therapists. For a long time, physical therapists have had a prominent role in the management of a patient's pain, without the cause or consequence of the same one, reason for which this revision wanted to integrate therapeutic actions such as the stress loading program, the desensitization and relaxation techniques, that have given excellent results, to the traditional (physical agents, ultrasound, sedative massage and different types of current), to Traumatic or visceral, that compromises the sympathetic nervous system reflexes.

DETERMINATION OF THE SACROILIAC ARTICU-LAR SURFACE WITH SPECIAL REFERENCE TO THE STRESS LOADING / 解剖学报

The diameters and projection area of the articular surfaces, contributed to the formation of the sacroiliac joint, were determined on 50 sets of pelvic bones with image analysing apparatus.By drawing a line connecting the most anterior point of the prominence to the deepest point of the posterior incisure, the articular surface may be divided into a superior and an inferior portions. The inferior portion was larger than the superior portion. Each portion of the articular surface on the ilium is slightly larger than that on the sacrum.In order to explore the relationship between the form of the articular surface and its function in transmitting the gravity of the human body, the stress of the neighbouring area near the anterior margin of the articular surface was determined. Moreover, the bony architecture on the cross section passing through the articular surface was observed. It suggests that the strain in the neighbouring area was in linear equation with the gravity loaded on the spinal column. The strongest stress was determined at the anterior margin of the anterior prominence and the thickness of the cortex lying on the relevant bones appears most obvious at the same sites. These results further improve that the bony architecture was consistent with the strain in bearing the body weight. Besides, the form of the articular surface was also adapted to its function.