Abstract
Earthquakes frequently occur in Japan. Even though countermeasures are thoroughly considered and well executed, earthquakes still impact facilities and experimental devices. The large ...relative displacements induced by an earthquake can damage beam pipe bellows and interfere with sub-detectors by causing the tolerance between them to disappear. Even magnet quenches have been triggered by induced voltages caused by the relative displacements between the superconducting solenoids (i.e., the detector solenoid and the compensating solenoids surrounding the final focus quadrupole magnets, or QCSs). In response, we installed acceleration sensors on the Belle II detector and mounted gap sensors on the QCSs to measure the relative displacements. These measurements enabled the characteristics of the earthquakes that have affected the Belle II detector to be analysed. Response spectrum analyses (RSAs) of the Belle II detector were conducted to evaluate the impact of earthquakes according to the ground motion measurements. We then compared the measurements to the RSA results, which led to an idea for a countermeasure.
REBCO coated conductors are now available from several industrial manufacturers and are expected to be promising conductors for high-field-magnet applications. Using these conductors, the development ...of solenoids capable of generating high magnetic fields of 20-30 T is ongoing in major high-field laboratories in the world. In addition, CERN recently launched a conceptual design study for the Future Circular Collider, in which a 20-T dipole magnet is listed as a candidate for the bending magnet of the main ring. However, there has been limited research published on the electrical transport properties of commercially available REBCO conductors in a high-field, low-temperature environment. For magnet designers, the transport properties are of the highest importance in choosing a suitable conductor, and the data form the bases for high-field magnet development. Therefore, in this work, a new sample holder, which allows the measurements of full-width conductors to be carried out relatively easily, was developed, and the transport properties of commercial REBCO conductors from seven manufacturers (AMSC, Fujikura, Shanghai Superconductor, SuNAM, SuperOx, SuperPower, and SWCC Showa) were investigated at 4.2 K in perpendicular fields of up to 18 T. The results show that the Ic values at 4.2 K clearly vary to some extent among these commercial conductors and the higher-current 4-mm-wide conductors have Ic values in the range of 230-305 A at 18 T and in the range of 320-424 A at 12 T.
Summary
Background
Angiosarcoma is a rare malignant neoplasm derived from endothelial cells, and because advanced angiosarcoma is resistant to standard chemotherapy its prognosis is poor. Therefore, ...new therapies are urgently needed. Heat shock protein (HSP)90 has been identified as a molecular chaperone that regulates various cancer‐related proteins. Numerous clinical trials are currently testing the effectiveness of HSP90 inhibitors in various types of malignancies.
Objectives
To investigate the role of HSP90 in the pathogenesis of angiosarcoma and whether the inhibition of HSP90 may have antitumour activity.
Methods
The expression of HSP90 protein in angiosarcoma was examined using immunohistochemistry and immunoblotting. The effects of HSP90 inhibition were proven using proliferation, migration and invasion assay in angiosarcoma cells. The mechanism of antitumour effect by HSP90 inhibition was investigated by the transfection of small interfering RNA (siRNA).
Results
The levels of HSP90 protein expression in cultured angiosarcoma cell lines were markedly increased compared with those in normal tissue cell lines. Immunohistochemical analyses revealed that the expression of HSP90 protein was strongly detected in angiosarcoma tissues compared with that in normal dermal vessels or senile angioma tissues. Ganetespib, an HSP90 inhibitor, with or without taxanes, inhibited the proliferation of angiosarcoma cells via apoptosis in a dose‐dependent manner. HSP90 siRNA suppressed the proliferation, migration and invasion of angiosarcoma cells. Knock‐down of HSP90 did not suppress vascular endothelial growth factor receptor 2 directly, but selectively suppressed several downstream targets of vascular endothelial growth factor signalling in angiosarcoma cells.
Conclusions
HSP90 could be a novel therapeutic target for angiosarcoma.
What's already known about this topic?
As advanced angiosarcoma is resistant to standard chemotherapy, its prognosis is poor and new therapies are urgently needed.
Heat shock protein (HSP)90 has been identified as a molecular chaperone that regulates various cancer‐related proteins. Numerous clinical trials are currently testing the effectiveness of HSP90 inhibitors in various types of malignancies.
What does this study add?
HSP90 is overexpressed in angiosarcoma.
The inhibition of HSP90 is effective in inhibiting the proliferation, migration and invasion of angiosarcoma cells.
Knock‐down of HSP90 did not directly supress vascular endothelial growth factor receptor 2, but selectively suppressed the downstream targets of vascular endothelial growth factor signalling in angiosarcoma cells.
What is the translational message?
HSP90 could be a novel therapeutic target for angiosarcoma.
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Linked Comment: Spiegelberg. Br J Dermatol 2017; 177:343–344
Magnetic properties of Cryophy were measured at room and cryogenic temperatures using ring samples. Sample-to-sample variation in permeability was evaluated in addition to measurement error. ...Permeability dependence on the maximum annealing temperature was examined using ring samples annealed at 1100 °C and 1170 °C. From these data, Cryophy was chosen as magnetic shielding material for the superconducting cavities in the main linac section of the cERL (compact Energy Recovery Linac) at KEK. Magnetic properties of Cryophy are presented along with the results of simulation based on the data obtained. The result of the high-power test of the cERL main linac cavities is reported at the end.
SuperKEKB is an electron–positron asymmetric-energy double-ring collider, which was built in Japan. It has been operated to explore new phenomena in B-meson decays. Hence, extremely higher luminosity ...is required. A collision scheme of low emittance with a large Piwinski angle called a “nano-beam scheme” has been adopted to achieve higher luminosity by squeezing the vertical beta function at the interaction point to be smaller than the bunch length. A “crab waist collision scheme” proposed by P. Raimondi et al. has also been adopted to improve the luminosity performance. The article presents an overview of the operation of the nano-beam and crab waist collision schemes at SuperKEKB.
In this paper, the linear and second order optics corrections for the KEK Accelerator Test Facility (ATF2) final focus beam line are described. The beam optics of the ATF2 beam line is designed based ...on a local chromaticity correction scheme similar to the ILC final focus system. Beam measurements in 2012 revealed skew sextupole field errors that were much larger than expected from magnetic field measurements. The skew sextupole field error was a critical limitation of the beam size at the ATF2 virtual interaction point (IP). Therefore, four skew sextupole magnets were installed to correct the field error in August 2012. By using the four skew sextupole magnets, the predicted tolerances of the skew sextupole field errors of the ATF2 magnets were increased. Furthermore, analyzing field maps of the sextupole magnets identified the source of the skew sextupole field error. After the field error source was removed, the IP vertical beam size could more easily be focused to less than 65 nm.
The SuperKEKB project underway at KEK will increase the KEKB luminosity by 40 times using nanobeam-interaction-region focusing optics. To achieve this high luminosity, the chromaticity correction of ...the collision beams is crucial; thus, special sextupole magnets, which can simultaneously produce normal and skew sextupole fields, are required in the straight sections around the interaction point. As a candidate for the sextupole, a cryocooled high-temperature superconducting magnet was proposed; development has begun. Here, the basic magnet design and the results of a small coil test are presented. The test studied the quench characteristics of the REBCO-impregnated coil.
Magnetic shielding is a key technology for superconducting RF cavities. The tolerance of the ambient magnetic field depends on factors such as the operating RF frequency and acceleration gradient, ...but can be lower than 1 μT. Conventional permalloy is often used for shielding low magnetic fields such as the earth's magnetic field. However, it is not well known how much the shielding effects degrade at cryogenic temperatures where superconducting cavities are operated. Some high Ni-content alloys, which are reported to maintain high permeability at cryogenic temperatures, are commercially available at present and are used for magnetic shielding of superconducting cavities at many laboratories. In this study, the magnetic properties of these materials are measured at room and cryogenic temperatures. The permeability dependence on the heat treatment conditions is studied by using one of the high Ni-content alloys. The effects of mechanical strain are also examined at room temperature. Evaluation of the magnetic shielding for the superconducting cavities of cERL is also discussed in this paper.
ATF2 (Accelerator Test Facility 2) is an international project designed for testing the final focus system that is envisaged at ILC. The primary project goal is to establish the hardware and beam ...handling technologies pertaining to transverse focusing of the electron beams to nearly 40 nm. The beam is extracted from the existing ATF ring to the new ATF2 beam line and brought to the final focus point which is about 90 m downstream of the extraction point. There are 43 quadrupole magnets in the ATF2 beam line, of which 28 (27 1 spare) are of the same type and were manufactured by Institute of High Energy Physics (IHEP), China. The tolerances on higher-order multipole components are tight, especially for the sextupole component. Magnetic field measurements with a harmonic coil were carried out on these quadrupole magnets at KEK and the integrated strength, the horizontal and vertical magnetic centers, median plane position and the higher-order multipole components were measured. The measurement results are summarized in this report.
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