Search

Introduction Spontaneous perforation of the oesophagus is diagnosed late in over 50% of cases. Misdiagnosis may be due to atypical presentations. Primary repair is technically demanding in this setting and the risk of failure is high. Presentation of case An 85 year-old lady presented with an atypical cohort of mild nonspecific symptoms in spite of a pleuro-mediastinal purulent collection secondary to an undiagnosed spontaneous perforation of the oesophagus occurred seven days before. Despite the extent of perforation (3 cm in length), the late diagnosis and the necrosis of the muscular wall, the oesophagus was successfully repaired by means of a stapler. Discussion The mechanism of the atypical presentation is discussed and possible modalities of treatment of delayed oesophageal perforations are reviewed, with particular reference to primary repair and to the possible use of staplers within this setting. Conclusion Even large spontaneous perforations of the oesophagus can result in a contained abscess, with no frank sepsis. Diagnosis can be missed for days in these cases. The attempt at primary repair of the oesophagus is still indicated. The use of a stapler is preferable in such cases as a perfect mucosal approximation is provided with minimal manipulation and with the use of inert, well tolerated material, which does not tend to become infected. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes the approved detailed design of the four Switching Network Units (SNUs) of the superconducting Central Solenoid of JT-60SA, the satellite tokamak that will be built in Naka, Japan, in the framework of the “Broader Approach” cooperation agreement between Europe and Japan. The SNUs can interrupt a current of 20kA DC in less than 1ms in order to produce a voltage of 5kV. Such performance is obtained by inserting an electronic static circuit breaker in parallel to an electromechanical contactor and by matching and coordinating their operations. Any undesired transient overvoltage is limited by an advanced snubber circuit optimized for this application. The SNU resistance values can be adapted to the specific operation scenario. In particular, after successful plasma breakdown, the SNU resistance can be reduced by a making switch. The design choices of the main SNU elements are justified by showing and discussing the performed calculations and simulations. In most cases, the developed design is expected to exceed the performances required by the JT-60SA project. [Copyright &y& Elsevier]

Abstract: The JT-60SA satellite tokamak will be built in Naka, Japan. One of the main aims of this machine is to achieve steady-state high-beta plasmas. To reach this result, passive stabilizing plate (SP) and resistive wall modes (RWM) active control system based on 18 in-vessel coils will be installed. In the present design, these coils are placed on the plasma side of the SP, behind the first wall. This solution maximizes the efficiency in producing fast magnetic fields into the plasma by minimizing the shielding effect of the passive structures. Then, if the power supply (PS) and the control system have sufficient dynamic performance, it is possible to control the RWM with very low magnetic fields. This allows minimizing the Ampere-turns and the power requested to control the RWM. Conversely, the very fast dynamics required represents one of the main issues for the design of the RWM control system. This paper, after having recalled the main specification data for the RWM control system deriving from the physics studies, describes the analyses performed to complete the set of requirements necessary for the PS design. The characterization of coils and feeders is shown and the voltage necessary to produce the required current and bandwidth is quantified. Possible connections among PS and coils are analyzed in order to achieve the highest possible flexibility in controlling the RWM with a reduced set of independent PS. Finally, considerations on reasonable voltage margins to cope with load uncertainties are given. [Copyright &y& Elsevier]