Ion storage rings have been serving as powerful tools in atomic and molecular physics since the high-energy magnetic ion storage ring were developed in the 1980s. In the 21st century, the ...technologies were inherited by the ‘electrostatic’ ion storage rings and brought a new opportunity of experiments with large molecular ions. Based on a number of advantages demonstrated in the electrostatic storage rings, new-generation cryogenic electrostatic rings were developed at Stockholm University, Max Planck Institute, and RIKEN. In this article, we review the historical background and technical developments of the RIKEN Cryogenic Electrostatic storage ring (RICE). We also overview the recent experiments with cold molecular ions at the cryogenic storage rings.
A timing system provides high-precision signals to allow the controls over a variety of hardware and software components in the accelerator complex. This is guaranteed by the radio frequency (RF) ...synchronization and trigger signal transmission for subsystems such as klystrons, pulsed magnets, and beam monitors. This trigger signal is usually generated at the same phase of an AC power line to follow the source of the fluctuation of an electrical grid and reduce unwanted variation of the beam quality. A long bucket selection cycle that is necessary for the SuperKEKB damping ring (DR) and main ring (MR) increases the complexity of the timing system. Uncertainty in the timing system and the trigger signal delivery failure caused by a drastic AC power line drift are observed. The cause and effect of timing system failures are analyzed. The solutions to improve the reliability of the timing system by upgrading the software are presented.
A 74-year-old female with caseous calcification of the mitral annulus and interstitial pneumonia was admitted with stroke due to calcific emboli. Computed tomography revealed an oval calcification ...with homogeneous density in and scattered calcification under the posterior mitral annulus, which was detected for the first time. Computed tomography performed during treatment for pneumonia and stroke showed changes in the shape and density of the caseous calcification; however, scattered calcification under the mitral annulus persisted. Operative findings were consistent with the signs on computed tomography: a white, soft, plaster-like content and similar scattered material around the chordae of the posterior leaflet.
Abstract
For the Future Circular Collider (FCC-ee), particular attention is drawn to the crucial role of the positron source. Two positron production schemes are considered for the FCC-ee: the ...conventional scheme and the crystal-based (hybrid) scheme that involves channelling radiation in the oriented crystals. A start-to-end simulation toolkit should be developed to design and optimize positron production and capture by considering the positron injector parameters, including the electron drive beam and final system acceptance. This paper presents the first results of benchmarking the FCC-ee positron source simulation tools using the SuperKEKB positron source currently in operation. The model starts with the production of positrons and target studies in Geant4. Then, the RF-Track code is used to capture and track the generated positrons through the capture section composed of a matching device and several accelerating structures embedded in the solenoid field to accelerate the positrons up to 120 MeV. After that, the positrons are further accelerated up to the energy of the Damping Ring (1.1 GeV). Finally, the SuperKEKB capture system is applied to the FCC-ee positron injector within the framework of the design studies.
We report 2 rare cases of tetraplegia after total aortic arch replacement with frozen elephant trunk that were attributable to cervical spinal stenosis. Cervical spinal stenosis can increase the ...vulnerability of the spinal cord to ischemia and may increase the risk of spinal cord injury in operation with circulatory arrest.
A 48-year-old man with Stanford type A acute aortic dissection underwent emergent total arch replacement with frozen elephant trunk (FET). Postoperative computed tomography showed inadvertent ...deployment of the FET into the false lumen. We therefore performed endovascular fenestration of the dissection flap and distal extension of the stent graft into the true lumen, which resulted in a thrombosed false lumen in the proximal descending thoracic aorta. Endovascular fenestration of the dissection flap and distal extension of the stent graft can be an effective bailout procedure for inadvertent deployment of the FET into the false lumen.
Metastatic cardiac tumors are commonly detected during autopsy. However, they are seldom diagnosed during life, and surgical resection is rarely indicated. Among the malignant tumors, colon cancer ...rarely metastasizes to the heart. We report a case of a 70-year-old woman with sigmoid colon cancer, which metastasized to her heart and caused obstruction of the right ventricular outflow tract. The tumor had already metastasized to the liver, lungs, periaortic lymph nodes, and peritoneum. Cardiopulmonary bypass surgery was performed to excise the right ventricular metastatic tumor and to reconstruct the tricuspid valve. Histological analysis of the specimen confirmed a metastatic adenocarcinoma. Although this surgery was performed as palliative cancer therapy, the patient's symptoms were satisfactorily improved. Follow-up echocardiography 2 months after her cardiac surgery showed no space-occupying mass in the right ventricle.
We describe aortic root dilatation, severe aortic regurgitation, and pulmonary artery stenosis that were accidentally diagnosed 23 years after the arterial switch operation for transposition of the ...great arteries in situs inversus. We successfully performed the modified Bentall procedure and pulmonary artery reconstruction. The pathology of the dilated aortic root revealed intimal atherosclerosis and linear necrosis of the tunica media, suggesting the vulnerability of the pulmonary artery to systemic pressure.
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