Discovery of

The new isotope ^{39}Na, the most neutron-rich sodium nucleus observed so far, was discovered at the RIKEN Nishina Center Radioactive Isotope Beam Factory using the projectile fragmentation of an intense ^{48}Ca beam at 345 MeV/nucleon on a beryllium target. Projectile fragments were separated and identified in flight with the large-acceptance two-stage separator BigRIPS. Nine ^{39}Na events have been unambiguously observed in this work and clearly establish the particle stability of ^{39}Na. Furthermore, the lack of observation of ^{35,36}Ne isotopes in this experiment significantly improves the overall confidence that ^{34}Ne is the neutron dripline nucleus of neon. These results provide new key information to understand nuclear binding and nuclear structure under extremely neutron-rich conditions. The newly established stability of ^{39}Na has a significant impact on nuclear models and theories predicting the neutron dripline and also provides a key to understanding the nuclear shell property of ^{39}Na at the neutron number N=28, which is normally a magic number.

How Different is the Core of

The structure of a neutron-rich ^{25}F nucleus is investigated by a quasifree (p,2p) knockout reaction at 270A MeV in inverse kinematics. The sum of spectroscopic factors of π0d_{5/2} orbital is found to be 1.0±0.3. However, the spectroscopic factor with residual ^{24}O nucleus being in the ground state is found to be only 0.36±0.13, while those in the excited state is 0.65±0.25. The result shows that the ^{24}O core of ^{25}F nucleus significantly differs from a free ^{24}O nucleus, and the core consists of ∼35% ^{24}O_{g.s.}. and ∼65% excited ^{24}O. The result may infer that the addition of the 0d_{5/2} proton considerably changes neutron structure in ^{25}F from that in ^{24}O, which could be a possible mechanism responsible for the oxygen dripline anomaly.

Swelling of Doubly Magic

Interaction cross sections for ^{42-51}Ca on a carbon target at 280 MeV/nucleon have been measured for the first time. The neutron number dependence of derived root-mean-square matter radii shows a significant increase beyond the neutron magic number N=28. Furthermore, this enhancement of matter radii is much larger than that of the previously measured charge radii, indicating a novel growth in neutron skin thickness. A simple examination based on the Fermi-type distribution, and mean field calculations point out that this anomalous enhancement of the nuclear size beyond N=28 results from an enlargement of the core by a sudden increase in the surface diffuseness of the neutron density distribution, which implies the swelling of the bare ^{48}Ca core in Ca isotopes beyond N=28.

Location of the Neutron Dripline at Fluorine and Neon.

A search for the heaviest isotopes of fluorine, neon, and sodium was conducted by fragmentation of an intense ^{48}Ca beam at 345 MeV/nucleon with a 20-mm-thick beryllium target and identification of isotopes in the large-acceptance separator BigRIPS at the RIKEN Radioactive Isotope Beam Factory. No events were observed for ^{32,33}F, ^{35,36}Ne, and ^{38}Na and only one event for ^{39}Na after extensive running. Comparison with predicted yields excludes the existence of bound states of these unobserved isotopes with high confidence levels. The present work indicates that ^{31}F and ^{34}Ne are the heaviest bound isotopes of fluorine and neon, respectively. The neutron dripline has thus been experimentally confirmed up to neon for the first time since ^{24}O was confirmed to be the dripline nucleus nearly 20 years ago. These data provide new keys to understanding the nuclear stability at extremely neutron-rich conditions.

Discovery of

The discovery of the important neutron-rich nucleus _{20}^{60}Ca_{40} and seven others near the limits of nuclear stability is reported from the fragmentation of a 345 MeV/u ^{70}Zn projectile beam on ^{9}Be targets at the radioactive ion-beam factory of the RIKEN Nishina Center. The produced fragments were analyzed and unambiguously identified using the BigRIPS two-stage in-flight separator. The eight new neutron-rich nuclei discovered, ^{47}P, ^{49}S, ^{52}Cl, ^{54}Ar, ^{57}K, ^{59,60}Ca, and ^{62}Sc, are the most neutron-rich isotopes of the respective elements. In addition, one event consistent with ^{59}K was registered. The results are compared with the drip lines predicted by a variety of mass models and it is found that the models in best agreement with the observed limits of existence in the explored region tend to predict the even-mass Ca isotopes to be bound out to at least ^{70}Ca.

Spectroscopy of Pionic Atoms in

We observed the atomic 1s and 2p states of π^{-} bound to ^{121}Sn nuclei as distinct peak structures in the missing mass spectra of the ^{122}Sn(d,^{3}He) nuclear reaction. A very intense deuteron beam and a spectrometer with a large angular acceptance let us achieve a potential of discovery, which includes the capability of determining the angle-dependent cross sections with high statistics. The 2p state in a Sn nucleus was observed for the first time. The binding energies and widths of the pionic states are determined and found to be consistent with previous experimental results of other Sn isotopes. The spectrum is measured at finite reaction angles for the first time. The formation cross sections at the reaction angles between 0° and 2° are determined. The observed reaction-angle dependence of each state is reproduced by theoretical calculations. However, the quantitative comparison with our high-precision data reveals a significant discrepancy between the measured and calculated formation cross sections of the pionic 1s state.

Evaluation of microbial diversity in the pilot-scale beer brewing process by culture-dependent and culture-independent method.

AIMS: In the brewing industry, microbial management is very important for stabilizing the quality of the product. We investigated the detailed microbial community of beer during fermentation and maturation, to manage beer microbiology in more detail. METHODS AND RESULTS: We brewed a beer (all-malt) and two beerlike beverages (half- and low-malt) in pilot-scale fermentation and investigated the microbial community of them using a next-generation sequencer (454 GS FLX titanium), quantitative PCR, flow cytometry and a culture-dependent method. From 28 to 88 genera of bacteria and from 9 to 38 genera of eukaryotic micro-organisms were detected in each sample. Almost all micro-organisms died out during the boiling process. However, bacteria belonging to the genera Acidovorax, Bacillus, Brevundimonas, Caulobacter, Chryseobacterium, Methylobacterium, Paenibacillus, Polaromonas, Pseudomonas, Ralstonia, Sphingomonas, Stenotrophomonas, Tepidimonas and Tissierella were detected at the early and middle stage of fermentation, even though their cell densities were low (below approx. 10(3) cells ml(-1) ) and they were not almost detected at the end of fermentation. CONCLUSIONS: We revealed that the microbial community of beer during fermentation and maturation is very diverse and several bacteria possibly survive during fermentation. SIGNIFICANCE AND IMPACT OF THE STUDY: In this study, we revealed the detailed microbial communities of beer using next-generation sequencing. Some of the micro-organisms detected in this study were found in beer brewing process for the first time. Additionally, the possibility of growth of several bacteria at the early and middle stage of fermentation was suggested.

First results from the new RIKEN superconducting electron cyclotron resonance ion source (invited).

The next generation heavy ion accelerator facility, such as the RIKEN radio isotope (RI) beam factory, requires an intense beam of high charged heavy ions. In the past decade, performance of the electron cyclotron resonance (ECR) ion sources has been dramatically improved with increasing the magnetic field and rf frequency to enhance the density and confinement time of plasma. Furthermore, the effects of the key parameters (magnetic field configuration, gas pressure, etc.) on the ECR plasma have been revealed. Such basic studies give us how to optimize the ion source structure. Based on these studies and modern superconducting (SC) technology, we successfully constructed the new 28 GHz SC-ECRIS, which has a flexible magnetic field configuration to enlarge the ECR zone and to optimize the field gradient at ECR point. Using it, we investigated the effect of ECR zone size, magnetic field configuration, and biased disk on the beam intensity of the highly charged heavy ions with 18 GHz microwaves. In this article, we present the structure of the ion source and first experimental results with 18 GHz microwave in detail.

Spectroscopy of 32Ne and the "Island of Inversion".

We report on the first spectroscopic study of the N=22 nucleus 32Ne at the newly completed RIKEN Radioactive Ion Beam Factory. A single gamma-ray line with an energy of 722(9) keV was observed in both inelastic scattering of a 226 MeV/u 32Ne beam on a carbon target and proton removal from 33Na at 245 MeV/u. This transition is assigned to the deexcitation of the first Jpi=2+ state in 32Ne to the 0+ ground state. Interpreted through comparison with state-of-the-art shell-model calculations, the low excitation energy demonstrates that the "island of inversion" extends to at least N=22 for the Ne isotopes.

Is driving a car a risk for Legionnaires' disease?

Legionnaires' disease (LD) is a major cause of severe community-acquired pneumonia but the source and mode of transmission are not always apparent, especially in sporadic cases. We hypothesized that LD can be acquired from the air-conditioning systems of motor cars. Swabs were taken from the evaporator compartments of the air-conditioning system of scrapped cars. Healthy subjects who were mainly employees of regional transportation companies were tested for antibody to Legionella pneumophila serogroups 1-6; they also completed a questionnaire. Legionella species were detected in 11/22 scrapped cars by the loop-mediated isothermal amplification method. The prevalence of microplate agglutination titres > or =1:32 was significantly higher in subjects who sometimes used car air-conditioning systems. Although we did not prove a direct link between Legionella spp. in the car evaporator and LD, our findings point to a potential risk of car air-conditioning systems in LD, which needs further investigation.

Development of large deformation in 62Cr.

The structure of neutron-rich isotopes 60Cr and 62Cr was studied via proton inelastic scattering in inverse kinematics. The deformation lengths (delta) for 60Cr and 62Cr were extracted as 1.12(16) and 1.36(14) fm, respectively, providing evidence for enhanced collectivity in these nuclei. An excited state at 1180(10) keV in 62Cr was identified for the first time. We adopted 4;{+} as its spin and parity, leading to the rapid increase of the Ex(4;{+})/E_{x}(2;{+}) ratio, which indicates the development of large deformation in 62Cr near N=40. Importance of the admixture of the gd-shell component above N=40 is also discussed by comparing with a modern shell model calculation.

Halo structure of the island of inversion nucleus 31Ne.

The cross sections for single-neutron removal from the very neutron-rich nucleus 31Ne on Pb and C targets have been measured at 230 MeV/nucleon using the RIBF facility at RIKEN. The deduced large Coulomb breakup cross section of 540(70) mb is indicative of a soft E1 excitation. Comparison with direct-breakup model calculations suggests that the valence neutron of 31Ne occupies a low-l orbital (most probably 2p(3/2)) with a small separation energy (S(n) approximately < 0.8 MeV), instead of being predominantly in the 1f(7/2) orbital as expected from the conventional shell ordering. These findings suggest that 31Ne is the heaviest halo system known.

Emission- and fluorescence-spectroscopic investigation of a glow discharge plasma: absolute number density of radiative and nonradiative atoms in the negative glow.

The excited-state atom densities in the negative glow of a direct-current glow discharge are derived from the spectral-line intensity of radiative atoms and the resonance-fluorescence photon flux of nonradiative atoms. The discharge is operated in a helium-argon gas mixture (molar fraction ratio 91:9; total gas pressure 5 Torr) at a dc current of 0.7-1.2 mA. The observations are made in the region of the maximum luminance in the cathode region, where high-energy electrons accelerated in the cathode fall are injected into the negative glow. The emission intensities of the He I, He II, Ar I, and Ar II spectral lines are measured with a calibrated tungsten ribbon lamp as an absolute spectral-radiance standard. Fluorescence photons scattered by helium and argon atoms in the metastable state and argon atoms in the resonance state are detected by the laser-induced fluorescence (LIF) method with the Rayleigh scattering of nitrogen molecules as an absolute standard of scattering cross section. The laser absorption method is incorporated to confirm the result of the LIF measurement. Excitation energies of the measured spectral lines range from 11.6 (Ar I) to 75.6 eV (He II), where the excitation energy is measured from the ground state of the neutral atom on the assumption that, in the plasma of this study, both the neutral and the ionic lines are excited by electron impact in a single-step process from the ground state of the corresponding neutral atoms. Experimental evidence is shown for the validity of this assumption.

Advanced oesophageal carcinoma in an 84-year-old treated with chemoradiotherapy.

We present a case of advanced oesophageal cancer with cardiac invasion in an 84-year-old male presenting with dysphagia and general malaise. Histological analysis of an endoscopic biopsy specimen revealed a poorly differentiated squamous cell carcinoma. Computed tomography indicated a thickened oesophageal wall that was compressing the left atrium, suggesting invasion of the heart, and oesophagography revealed a polypoid lesion 9 cm in length. No distant metastases were seen on computed tomography. The patient was given chemotherapy with 10 mg/m2 cisplatin on days 1 and 4 every week for 5 weeks and concurrent radiotherapy at a dose of 2 Gy five times per week (total dose 52 Gy). After 4 weeks, the mass was no longer visible on oesophagography or endoscopic examination. The patient was free of recurrence and metastases for 4.5 years. In conclusion, chemoradiotherapy may be curative in elderly patients with unresectable oesophageal carcinoma.

Traditional Chinese medicine and Kampo: a review from the distant past for the future.

Traditional Chinese medicine (TCM) is a complete system of healing that developed in China about 3000 years ago, and includes herbal medicine, acupuncture, moxibustion and massage, etc. In recent decades the use of TCM has become more popular in China and throughout the world. Traditional Japanese medicine has been used for 1500 years and includes Kampo-yaku (herbal medicine), acupuncture and acupressure. Kampo is now widely practised in Japan and is fully integrated into the modern health-care system. Kampo is based on TCM but has been adapted to Japanese culture. In this paper we review the history and characteristics of TCM and traditional Japanese medicine, i.e. the selection of traditional Chinese herbal medicine treatments based on differential diagnosis, and treatment formulations specific for the 'Sho' (the patient's symptoms at a given moment) of Japanese Kampo--and look at the prospects for these forms of medicine.

Angiotensin-II receptor antagonist alleviates non-alcoholic fatty liver in KKAy obese mice with type 2 diabetes.

We examined the effects of the angiotensin-II receptor antagonist candesartan on non-alcoholic fatty liver (NAFL) and circulating adiponectin concentrations in KKAy obese mice with type 2 diabetes mellitus. The KKAy mice were randomly assigned to receive either candesartan at a once-daily dose of 10 mg/kg (n = 5) or placebo (n = 5). The differences in liver weight, histological evaluation of hepatic lipid infiltration, serum adiponectin concentration and hepatic adiponectin mRNA levels between the two groups were determined on day 7 after treatment was initiated. Candesartan-treated mice demonstrated significantly lower liver weights and reduced lipid droplets in hepatic cells compared with control mice. The circulating adiponectin levels and hepatic expression of adiponectin mRNA were significantly higher in candesartan-treated mice than control mice. These results suggest that candesartan might alleviate NAFL through elevation of circulating adiponectin levels in KKAy obese mice with type 2 diabetes mellitus.

Plasma adiponectin levels in post-menopausal women receiving hormone replacement therapy.

This study aimed to evaluate the correlation between plasma adiponectin levels and plasma lipid and lipoprotein levels in post-menopausal women (PMW) receiving hormone replacement therapy (HRT). Various clinical and biochemical parameters, including plasma lipid and lipoprotein concentrations and adiponectin levels, were measured in 54 healthy PMW before and after 3 and 6 months of HRT. Control groups consisted of women aged < 40 years (n = 20) or > 60 years (n = 17). PMW had significantly lower baseline adiponectin levels compared with the younger or older control groups, but adiponectin concentrations were not significantly altered after 3 or 6 months of HRT. Adiponectin levels in PMW were positively correlated with plasma high-density lipoprotein-cholesterol levels and were negatively correlated with body mass index and triglyceride levels. Our data suggest that circulating adiponectin may contribute to lipid homeostasis in PMW. Further studies are needed to elucidate the effects of HRT and oestrogen on adiponectin levels.

Selective binding of sucralfate to endoscopic mucosal resection-induced gastric ulcer: evaluation of aluminium adherence.

We evaluated the effect of sucralfate in patients with early gastric cancer in endoscopic mucosal resection (EMR)-induced gastric ulcers, and in rats with acetic acid-induced ulcers, by measuring concentrations of aluminium adhering to mucosal lesions. Twenty-two patients who underwent EMR received sucralfate with or without ranitidine and were examined endoscopically after 1 week, 2 weeks and 3 weeks. Gastric juice pH and concentration of aluminium in samples of ulcerated and normal mucosa were measured at various time-points. Good ulcer healing was observed in all patients. Significantly higher concentrations of aluminium were found in ulcerated tissue compared with normal mucosa. This selective binding of sucralfate was even found 12 h after drug administration and was confirmed in acetic acid-induced ulcers in 40 rats. Neutral rather than acid gastric juice was observed up to 12 h after the administration of sucralfate alone. These results suggest that sucralfate with or without ranitidine may contribute to the healing of EMR-induced ulcers by selectively binding to lesions.