0000000000579823
AUTHOR
M. Koizumi
showing 5 related works from this author
SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study
2021
Abstract Background Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18–49, 50–69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results NNVs were more favourable in su…
Production and trapping of carbon clusters for absolute mass measurements at ISOLTRAP
2001
Singly-charged carbon clusters C/sub n//sup +/ (n >or= 1) have been produced by laser-induced desorption and fragmentation of C/sub 60/ fullerenes and have been injected into and stored in the Penning trap system of the ISOLTRAP mass spectrometer at ISOLDE/CERN. The present study is the first step to extend the until now direct mass measurements at ISOLTRAP to absolute mass measurements by using clusters of /sup 12/C. (10 refs).
New states in heavy Cd isotopes and evidence for weakening of the N = 82 shell structure
2000
A chemically selective laser ion source has been used in a β-decay study of heavy Ag isotopes into even-even Cd nuclides. Gamma-spectroscopic techniques in time-resolving event-by-event and multiscaling modes have permitted the identification of the first 2+ and 4+ levels in 126Cd78, 128Cd80, and tentatively the 2+ state in 130Cd82. From a comparison of these new states in 48Cd with the E(2+) and E(4+)/E(2+) level systematics of 46Pd and 52Te isotopes and several recent model predictions, possible evidence for a weakening of the spherical N = 82 neutron-shell below double-magic 132Sn is obtained.
$\beta$ - decay of the M$_{T}$=-1 nucleus $^{58}$Zn studied by selective laser ionization
1998
$\beta$ - decay of $^{58}$Zn has been studied for the first time. A new laser ion-source concept has been used to produce mass-separated sources for $\beta$ and $\gamma$ - spectroscopy. The half-life of $^{58}$Zn was determined to be 86(18) ms. Comparisons are made with previous data from charge-exchange reactions. Our Gamow-Teller strength to the 1$^{+}$ state at 1051 keV excitation in $^{58}$Cu agrees well with the value extracted from a recent ($^{3}$He, t) study. Extensive shell-model calculations are presented.
Velocity distribution of ion beams from the RIKEN IGISOL
1992
Abstract A direct measurement of the velocity distribution of ion beams from an ion-guide isotope separator on-line (IGISOL) was carried out at RIKEN with a technique of laser spectroscopy. The skimmer-potential and gas-cell pressure dependence of the velocity distribution were also measured. The velocity distribution was found to be about two times narrower than that estimated from the mass resolving power (MRP). It is pointed out that the velocity spread deduced from MRP is considerably overestimated at various conditions. The way of improvement to make the velocity distribution of the ion beam from the IGISOL narrower and the feasibility of fast atomic-beam collinear laser spectroscopy a…