New readout and data-acquisition system in an electron-tracking Compton camera for MeV gamma-ray astronomy (SMILE-II)

For MeV gamma-ray astronomy, we have developed an electron-tracking Compton camera (ETCC) as a MeV gamma-ray telescope capable of rejecting the radiation background and attaining the high sensitivity of near 1 mCrab in space. Our ETCC comprises a gaseous time-projection chamber (TPC) with a micro pattern gas detector for tracking recoil electrons and a position-sensitive scintillation camera for detecting scattered gamma rays. After the success of a first balloon experiment in 2006 with a small ETCC (using a 10$\times$10$\times$15 cm$^3$ TPC) for measuring diffuse cosmic and atmospheric sub-MeV gamma rays (Sub-MeV gamma-ray Imaging Loaded-on-balloon Experiment I; SMILE-I), a (30 cm)$^{3}$ medium-sized ETCC was developed to measure MeV gamma-ray spectra from celestial sources, such as the Crab Nebula, with single-day balloon flights (SMILE-II). To achieve this goal, a 100-times-larger detection area compared with that of SMILE-I is required without changing the weight or power consumption of the detector system. In addition, the event rate is also expected to dramatically increase during observation. Here, we describe both the concept and the performance of the new data-acquisition system with this (30 cm)$^{3}$ ETCC to manage 100 times more data while satisfying the severe restrictions regarding the weight and power consumption imposed by a balloon-borne observation. In particular, to improve the detection efficiency of the fine tracks in the TPC from $\sim$10\% to $\sim$100\%, we introduce a new data-handling algorithm in the TPC. Therefore, for efficient management of such large amounts of data, we developed a data-acquisition system with parallel data flow.Comment: 11 pages, 24 figure

Percutaneous coronary intervention strategy for acute coronary syndrome caused by spontaneous coronary artery dissection for relieving ongoing ischemia—Case series and literature review

AbstractAlthough spontaneous coronary artery dissection (SCAD) is one of the causes of acute coronary syndrome (ACS) or sudden cardiac death, its standard management, especially primary percutaneous coronary intervention (PCI) in ACS patients with ongoing ischemia, has not been established. We experienced three ACS patients with SCAD who were treated with a different strategy of primary PCI. Each PCI strategy led to different clinical and procedural results. We describe here such PCI strategies and results, and also discuss the literature regarding primary PCI strategies for SCAD-induced ACS patients with ongoing ischemia.<Learning objective: SCAD is a cause of ACS. However, the treatment strategy of primary PCI for SCAD has not been fully investigated. We used different PCI strategies for three SCAD patients with ongoing ischemia. Our case series suggested that plain old balloon angioplasty is an acceptable option to avoid coronary stenting because the majority of patients were young menstruating women. Coronary vasospasm might be associated with SCAD. Treatment with vasodilators could be a potential pharmacological option for avoiding recurrence of SCAD.

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Influence of scandium on superplastic ductilities in an Al-Mg-Sc alloy

Ultrafine grain sizes, of the order of approximately 0.2 ?m, may be introduced into Al-Mg-Sc alloys by subjecting the material to severe plastic deformation through the process of equal-channel angular pressing (ECAP). Experiments were conducted to evaluate the influence of the solution treatment temperature on the ductility of an Al-3% Mg-0.2% Sc alloy after ECAP. The results show the highest ductilities are achieved when the solution treatment temperature is within the narrow range of approximately 878 to about 883 K, immediately below the temperature associated with the onset of partial melting. These high temperatures serve to maximize the amount of scandium in solid solution and this leads, on subsequent heating, to an extensive precipitation of fine secondary Al3Sc particles which inhibit grain growth at the higher temperatures. Conversely, solution treatments at temperatures below approximately 878 K give less Sc in solid solution within the matrix and the precipitation of the Al3Sc particles is then insufficient to retain a uniform ultrafine microstructure

Deactivation of external acid sites of H-mordenite by modification with lanthanide oxides for the isopropylation of biphenyl and the cracking of 1,3,5-triisopropylbenzene and cumene

The modification of H-mordenite (MOR) with lanthanide oxides La O , CeO , Pr O , Sm O , Dy O , and Yb O was examined for the deactivation of external acid sites and confirmed in the cracking of 1,3,5-triisopropylbenzene (TIPB) and cumene (IPB) and in the isopropylation of biphenyl (BP). The cracking of TIPB, which cannot enter the pores of MOR, shows that external acid sites were effectively deactivated by the modification of MOR with the lanthanide oxides in small amounts. Only the cracking of IPB over CeO -modified MOR exhibited excellent catalytic activities, even at a 30 wt % metal loading, whereas the activities of other lanthanide oxide-modified MORs rapidly decreased as the loadings were increased because pore entrances became choked. The isomerization of 4,4'-diisopropylbiphenyl (4,4'-DIPB) during the isopropylation of BP at high temperatures such as 300 °C was also effectively prevented by the modification of MOR with the lanthanide oxides. Particularly, CeO -modified MOR remained highly active even at a 30 wt % loading. Other lanthanide oxides can deactivate the isomerization of 4,4'-DIPB at 5-10 wt % loadings without significant loss of the activities at 300 °C, while the activity was rapidly lost as the loading amount was increased. The physicochemical properties of lanthanide oxide-modified MORs indicate that the lanthanide oxides modify the surface properties of MOR. The amounts of N , o-xylene, and NH adsorbed on MORs mostly remained high after CeO modification; however, they rapidly decreased when loadings of the other oxides increased. These results show that CeO remains the open pores at high loadings; however, the other oxides reduce the size of pore entrances as the loading is increased