Usefulness of dynamic stabilisation with mobile percutaneous pedicle screw for thoracic vertebral fractures in diffuse idiopathic skeletal hyperostosis

We report a case of vertebral fracture with diffuse idiopathic skeletal hyperostosis (DISH) who underwent posterior dynamic stabilisation using mobile percutaneous pedicle screws (PPS) with 1 above-1 below and obtained good bone fusion. A 76-year-old man experienced severe low back pain after he fell backward 1 m off a stepladder during work. A 12th thoracic vertebral fracture with DISH was observed. As the fractured part was unstable due to a three-column injury, and the conservative treatment of resting was not successful, posterior dynamic stabilisation with a mobile PPS between T11–L1 was performed the 38th day after injury. Immediately after surgery, a fracture gap was observed, but 5 months later, vertebral body height was shortened by about 4 mm, and good bone fusion was observed without loosening of the screw. The mobile PPS flexibly adapts to spinal plasticity and may be useful for bone union in vertebral fractures associated with DISH.

Dynamic stabilisation during the drainage of thin film polymer solutions

The drainage and rupture of polymer solutions was investigated using a dynamic thin film balance. The polymeric nature of the dissolved molecules leads to significant resistance to the deformation of...

Design of The Vibrostabilisation Stand For Reducing Residual Stresses in Discs Used In The Construction of Multi-Plate Clutches and Brakes

Heavy-duty, oil-cooled brake discs (MMOTs) are often used in heavy-duty brake systems manufactured by companies such as Caterpilar, Clark, Komatsu and Liebherr. These discs are usually made of special steels, and in most cases, the flatness of the working surfaces should not exceed 0.15–0.30 mm. Although the technological processes of friction disc production include several stages of heat treatment and grinding, the required accuracy is not achieved in some cases. In addition, the remaining residual stresses lead to the deformation of the discs during their lifetime. In production practice, three methods are used to reduce residual stresses: thermo-fixing, dynamic stabilisation and vibratory stabilisation consisting in bringing discs to transverse resonance vibrations and maintaining resonance until significant stress reduction. The article proposes a method of stabilising the discs using the resonance phenomenon at the first few frequencies. In this article, Cauchy’s function method and characteristic series method are used to develop solution value problem for clamped circular plates with discrete inclusions as concentrated masses and springs. Calculation methods for quick estimation of the own frequency of discs with additional ring mass enabling the use of low power vibration inductors are presented. The use of a special membrane and a pneumatic cushion in the construction of the stand allows to induce vibrations of higher frequencies.

Encouraging Medium-term Results of Wallis Second Generation Dynamic Stabilisation Device

Background. Aim of this prospective study was to evaluate safety and efficacy of second generation Wallis system for degenerative lumbar disc disease. Material and methods. 25 patients underwent discectomy and insertion of Wallis system. Outcome assessment was done using Modified Oswestry disability index (ODI) and visual analogue scale (VAS) for backache and leg pain. Results. The mean follow-up was 20.5 months. The mean VAS for backache and leg pain showed significant improvement from 7.2 to 3.0 (p<0.001) and mean modified Oswestry disability index showed significant improvement from 59.1 to 24.7 (p<0.001). Only one patient (4%) underwent revision surgery for persistent pain due to granulation tissue deep to the implant. There were no other complications. Conclusion. The Wallis spine system is a safe and effective implant for treating degenerative lumbar disc disease.

A study of QCD at finite density using complex Langevin dynamics

Numerical simulations are a standard tool to investigate field theories in non-perturbative regimes. Typical algorithms used to evaluate path integrals in Euclidean space rely on importance sampling methods; i.e., a probabilistic interpretation of the Boltzmann weight eS. However, many theories of interest suffer from the infamous sign problem: the action is complex and the Boltzmann weight cannot be used as a probability distribution. Complex Langevin simulations allow numerical studies of theories that exhibit the sign problem, such as QCD at finite density. In this thesis, we study methods to investigate the phase diagram of QCD in the temperature{chemical potential plane, using the complex Langevin method. We provide results on the phase diagram for the heavy-denseapproximation of QCD (HDQCD) for three spatial volumes, using complex Langevin and the gauge cooling technique. We also present polynomial fits of the critical temperature as function of the chemical potential for each volume. Subsequently, we discuss instabilities encountered during this study, which motivated a novel technique, named Dynamic Stabilisation, which will be introduced and the theoretical ideas behind it, explained. Dynamic stabilisation was, then, used in an investigation of the dependency of the critical chemical potential on the hopping parameter. The two previous studies were used to guide a second examination of the HDQCD phase diagram, focussed around the phase boundary. Lastly, we present preliminary results on the phase diagram of QCD with fully dynamical quarks at high temperatures. This shows that complex Langevin, augmented with gauge cooling and dynamic stabilisation, is suited for investigating QCD at finite chemical potential.