Search

In April 2018, the Clinical Trials Act pertaining to investigator-initiated clinical trials was passed in Japan. The purpose of this study was to investigate activity in investigator-initiated clinical studies before and after enforcement of the new Clinical Trials Act. This was done by analysing the records of the Ethics Committee of Tokushima University Hospital, which reviews studies based on the Japanese government's Ethical Guidelines for Medical and Health Research Involving Human Subjects prior to the Clinical Trials Act, and records of the Certified Review Board established at Tokushima University under the Clinical Trials Act in 2018. The number of new applications to these two review boards during fiscal years 2015-2017 (pre-Act) and fiscal years 2018 and 2019 (post-Act) were used as an indicator of activity in investigator-initiated clinical studies. The number of new applications to the Ethics Committee was 303, 261, 316, 303, and 249 in 2015, 2016, 2017, 2018, and 2019, respectively. The data show that the total number of new interventional studies decreased from 50.3 in average in 2015-2017 (pre-Act) to 42 in 2018 and 40 in 2019 (post-Act), respectively. These results suggest that fewer interventional studies were started following enforcement of the new Clinical Trials Act. To confirm this trend and identify contributing factors, further studies are required. In addition, possible way, such as broader contribution of clinical research coordinators, to promote clinical studies in the new Clinical Trials Act era should be examined.

Spectroscopy of 16B plays an essential role in understanding the halo structure in 17B, but very limited knowledge has so far been obtained. We have carried out a kinematically complete measurement on the spectroscopy of 16B by using quasi-free (p,pn) reaction on 17B. The level scheme of 16B up to 5 MeV was made clear for the first time.

International audience; Dineutron decay is a forefront topic in nuclear structure that still lacks a firm experimental claim. The spontaneous emission of a dineutron should be favored in nuclei that are unbound with respect to two-neutron emission but bound with respect to single-neutron emission. A very interesting candidate can be found by adding two neutrons to the most neutron-rich Beryllium isotope,$^{14}$Be, a well-known 2n-halo nucleus. The intriguing nature of the phenomenon has motivated recent theoretical calculations and a new experimental campaign at RIKEN RIBF. In this work, the decay properties of$^{16}$Be and the structure of$^{15}$Be have been probed via the proton-knockout reaction from a$^{17}$B beam.

International audience; The dependence of the single-particle strength on the difference between proton and neutron separation energies is studied for oxygen isotopes in a wide range of isospins. The cross sections of the quasi-free (p, 2p) reaction on 14,16,18,22,24O were measured at intermediate energies. The measured cross sections are compared to predictions based on the distorted wave impulse approximation and shell-model psd valence-space spectroscopic factors. The reduction factors, which are the ratio of the experimental cross sections to the theoretical predictions, show no apparent dependence on the proton–neutron separation energy difference. The result is compatible with the result of the (e, e p) reaction on stable targets and with the predictions of recent ab initio calculations.

The charge-exchange (p, n) reaction at 220 MeV has been measured to extract the strength distribution of Gamow-Teller transitions from the doubly magic unstable nucleus 132Sn. A recently developed experimental technique of measuring the (p, n) reaction in inverse kinematics has been applied to the study of unstable nuclei in the mass region around A∼100 for the first time. We have combined the low-energy neutron detector WINDS and the SAMURAI spectrometer at the RIKEN radioactive isotope beam factory (RIBF). The particle identification plot for the reaction residues obtained by the spectrometer provides the clear separation of the CE reaction channel from other background events, enabling us to identify kinematic curves corresponding the (p, n) reaction. Further analysis to reconstruct the excitation energy spectrum is ongoing., International Conference on Nuclear Structure and Related Topics (NSRT15)

We report for the first time the discrimination of the core fragment knockout and valence nucleon knockout reaction mechanisms at medium energy range, by the use of the recoil proton tagging technique. Intense 8He beams at 82.3 MeV/u were supplied by the RIPS beam line at RIKEN, and impinged on both hydrogen and carbon targets. Recoil protons were detected in coincidence with the forward moving core fragments and neutrons. The core fragment knockout mechanism is identified through the polar angle correlation and checked by various kinematics relations. This mechanism may be used to extract the cluster structure information of unstable nuclei. On the other hand, with the selection of the tagged valence nucleon knockout mechanism, a narrower peak of 7He ground state is obtained. The extracted neutron spectroscopic factor S n = 0.512 ( 18 ) is relatively smaller than the no-tagged one, and is in good agreement with the prediction of ab initio Greenʼs function Monte Carlo calculations.

The energy spectrum of the 2 H(d,pn) reaction at 0° at 270 MeV was obtained at RIKEN Accelerator Research Facility. The spectrum in the kinematical region where the resulting pn pair has the relative energy smaller than ∼2 MeV was analyzed by plane-wave impulse approximation calculations assuming the configurations of final state interaction with s-wave.

High-precision vector and tensor analyzing powers of elastic deuteron-proton (d + p) scattering have been measured at intermediate energies to investigate effects of three-nucleon forces. Angular distributions in the range of 70-120 degrees in the center-of mass frame for incident-deuteron energies Ed (lab)(d) = 130 and 180 MeV were obtained using the RIKEN facility. The beam polarization was unambiguously determined by measuring the C-12(d,alpha)B-10(2(+)) reaction at 0 degrees. Results of the measurements are compared with state-of-the-art three-nucleon calculations. The present modeling of nucleon-nucleon forces and its extension to the three-nucleon system is not sufficient to describe the high-precision data consistently and requires, therefore; further investigation.

A complete high-precision set of deuteron analyzing powers for elastic deuteron-proton (dp) scattering at 250 and 294 MeV/nucleon has been measured. These data and previously existing data sets for the cross section at similar energies are compared to the results of three-nucleon Faddeev calculations based on modern nucleon-nucleon (NN) potentials alone or combined with two models of three-nucleon forces: the Tucson-Melbourne 99 and Urbana IX. Large discrepancies between pure NN theory and data, which are not resolved by the current three-nucleon forces, were found at c.m. backward angles θc.m.≳120∘ for all the deuteron analyzing powers and the cross section. Because only small relativistic effects were found for the deuteron analyzing powers and the cross section, the inclusion of short-range components of the three-nucleon force is probably required to get a better description of the data.

Knockout reaction experiment for 8He at 82.3 MeV/u on Hydrogen target was carried out at the RIPS beam line in RIKEN. Recoil protons were detected in coincidence with the forward moving core fragments and neutrons. The quasi-free knockout mechanism is identified through the polar angle correlation and checked by various kinematics conditions. The absolute differential cross sections for 6He core cluster are obtained and compared with the simple Glauber model calculations. The extracted spectroscopic factor is close to unity and a shrinking of the cluster size is evidenced.

The neutron-rich, even-even ^Pd isotopes were studied via in-beam γ -ray spectroscopy at the RIKEN Radioactive Isotope Beam Factory. Excited states at 499(9), 590(11), and 686(17) keV were found in the three isotopes, which we assign to the respective 2^_ →0^_ decays. In addition, candidates for the 4^_＜1> states at 1164(20) and 1300(22) keV were observed in ^Pd and ^Pd, respectively. The resulting E_x (2^_) systematics are similar to the Xe (Z=54 ) isotopic chain and theoretical predictions by the proton-neutron interacting boson model (IBM-2), indicating the magic nature of N=82 in the Pd isotopes.

A knockout reaction experiment was carried out using a 6He beam at 82.3 MeV/u impinged on carbon and hydrogen targets. The recoil protons were detected in coincidence with the forward moving charged fragments and neutrons. It is demonstrated that through the correlation between the recoil protons and forward moving charged fragments, the core fragment knockout and valence nucleon knockout reaction mechanisms can be discriminated at energies around 100 MeV/u. The 5He ground-state resonance was reconstructed based on the selection of the valence nucleon knockout mechanism. The resonance parameters were obtained for both carbon and hydrogen targets, which are consistent with those previously reported in the literature. The importance of selecting appropriate reaction mechanisms is discussed based on reconstructions using events with larger transverse momentum transfer.

The vector Ay and tensor analyzing powers Ayy and Axx for dp- elastic scattering were measured at Td = 880 MeV over the c.m. angular range from 60 to 140 degrees at the JINR Nuclotron. The data are compared with predictions of different theoretical models based on the use of nucleon-nucleon forces only. The observed discrepancies of the measured analyzing powers from the calculations require the consideration of additional mechanisms., Comment: 5 pages,3 figures

A complete high precision set of deuteron analyzing powers for elastic deuteron-proton ($dp$) scattering at 250 MeV/nucleon (MeV/N) has been measured. The new data are presented together with data from previous measurements at 70, 100, 135 and 200 MeV/N. They are compared with the results of three-nucleon (3N) Faddeev calculations based on modern nucleon-nucleon (NN) potentials alone or combined with two models of three nucleon forces (3NFs): the Tucson-Melbourne 99 (TM99) and Urbana IX. At 250 MeV/N large discrepancies between pure NN models and data, which are not resolved by including 3NFs, were found at c.m.\ backward angles of $\theta_{\rm c.m.}\gtrsim 120^\circ$ for almost all the deuteron analyzing powers. These discrepancies are quite similar to those found for the cross section at the same energy. We found small relativistic effects that cannot resolve the discrepancies with the data indicating that other, short-ranged 3NFs are required to obtain a proper description of the data., Comment: submitted to Phys. Rev. C

Differential cross sections for the elastic scattering of halo nucleus 6He on proton target were measured at 82.3 MeV/u. The experimental results are well reproduced by optical model calculations using global potential KD02 with a reduction of the depth of real volume part by a factor of 0.7. A systematic analysis shows that this behavior might be related to the weakly bound property of unstable nuclei.

The status and prospects of 2-nucleon and 3-nucleon short range correlations (SRCs) studies at Nuclotron-M (JINR) are presented. This program is focused on the investigations of the spin part of SRCs with polarized deuteron beam from new high intensity polarized deuterons ion source which is under development at JINR. The wide experimental program on the systematic studies of the polarization effects in dp- elastic scattering, dp- nonmesonic breakup, dd → 3Hen(3Hp) and d3He → p4He reactions sensitive to SRCs using both internal and extracted beam at Nuclotron-M is presented.

To the Editor: Murine typhus is an arthropod-borne infectious disease caused by Rickettsia typhi, which is distributed widely around the world (1–4). In Japan, tsutsugamushi disease occurs most frequently in persons infected with rickettsioses (5). Spotted fever caused by R. japonica also occurs in the southwestern part of Japan (6,7). In the 1940s and 1950s, many murine typhus cases were reported in Japan. These diagnoses were made according to the clinical features of the illness and the reactivity of the serum samples to OX19 in Weil-Felix tests. A few cases were diagnosed on the basis of symptoms exhibited by animals infected with isolated rickettsiae and complement fixation tests, in addition to results of the Weil-Felix tests. The Weil-Felix test is useful for preliminary screening of rickettsiosis; however, the reaction could indicate epidemic typhus or spotted fever in some cases. Since 1958, only three murine typhus cases have been reported in Japan (8). In these cases, no serologic tests for epidemic typhus were conducted. Serum sample from patients with epidemic typhus and murine typhus frequently possess serologic cross-reactivity to R. typhi and R. prowazekii, respectively (9). Thus, the possibility of epidemic typhus could not be excluded definitively in these cases. On May 4, 2003, a 56-year-old man living in Tokushima, Japan, sought medical care; he had a temperature of 39.1°C and exanthema on the trunk and the upper limbs. No surface lymph nodes were palpable. He was treated with lincomycin and cefditoren pivoxil with no improvement. On day 3, the patient informed caregivers that he had been in a bamboo grove on days 1 and 11 before the onset of symptoms. C-reactive protein of the serum sample collected on day 3 was positive (= 7.6 mg/dL). From this finding, spotted fever was suspected; the disease is endemic in Tokushima. On day 4, the exanthema had spread systemically, and treatment with minocycline was started, which led to a gradual decrease in fever and rashes. The patient was admitted to the Tokushima University Hospital on day 6 of the illness for diagnosis and further treatment. Serum samples were collected from the patient on days 5, 6, 9, 20, and 34. Indirect immunoperoxidase tests on the serum samples for tsutsugamushi disease, spotted fever, murine typhus, and Q fever on day 5 of the illness were negative for immunoglobulin (Ig) G and IgM antibodies (