78Ni revealed as a doubly magic stronghold against nuclear deformation.

Nuclear magic numbers correspond to fully occupied energy shells of protons or neutrons inside atomic nuclei. Doubly magic nuclei, with magic numbers for both protons and neutrons, are spherical and extremely rare across the nuclear landscape. Although the sequence of magic numbers is well established for stable nuclei, experimental evidence has revealed modifications for nuclei with a large asymmetry between proton and neutron numbers. Here we provide a spectroscopic study of the doubly magic nucleus 78Ni, which contains fourteen neutrons more than the heaviest stable nickel isotope. We provide direct evidence of its doubly magic nature, which is also predicted by ab initio calculations based on chiral effective-field theory interactions and the quasi-particle random-phase approximation. Our results also indicate the breakdown of the neutron magic number 50 and proton magic number 28 beyond this stronghold, caused by a competing deformed structure. State-of-the-art phenomenological shell-model calculations reproduce this shape coexistence, predicting a rapid transition from spherical to deformed ground states, with 78Ni as the turning point.

Serum immunoglobulin G antibody titer to Fusobacterium nucleatum is associated with unfavorable outcome after stroke.

Stroke can be a cause of death, while in non-fatal cases it is a common cause of various disabilities resulting from associated brain damage. However, whether a specific periodontal pathogen is associated with increased risk of unfavorable outcome after stroke remains unknown. We examined risk factors for unfavorable outcome following stroke occurrence, including serum antibody titers to periodontal pathogens. The enrolled cohort included 534 patients who had experienced an acute stroke, who were divided into favorable (n = 337) and unfavorable (n = 197) outcome groups according to modified ranking scale (mRS) score determined at 3 months after onset (favorable = score 0 or 1; unfavorable = score 2-6). The associations of risk factors with unfavorable outcome, including serum titers of IgG antibodies to 16 periodontal pathogens, were examined. Logistic regression analysis showed that the initial National Institutes of Health stroke scale score [odds ratio (OR) = 1·24, 95% confidence interval (CI) = 1·18-1·31, P < 0·001] and C-reactive protein (OR = 1·29, 95% CI = 1·10-1·51, P = 0·002) were independently associated with unfavorable outcome after stroke. Following adjustment with those, detection of the antibody for Fusobacterium nucleatum ATCC 10953 in serum remained an independent predictor of unfavorable outcome (OR = 3·12, 95% CI = 1·55-6·29, P = 0·002). Determination of the antibody titer to F. nucleatum ATCC 10953 in serum may be useful as a predictor of unfavorable outcome after stroke.

Sequential Nature of (p,3p) Two-Proton Knockout from Neutron-Rich Nuclei.

Twenty-one two-proton knockout (p,3p) cross sections were measured from neutron-rich nuclei at ∼250 MeV/nucleon in inverse kinematics. The angular distribution of the three emitted protons was determined for the first time, demonstrating that the (p,3p) kinematics are consistent with two sequential proton-proton collisions within the projectile nucleus. Ratios of (p,3p) over (p,2p) inclusive cross sections follow the trend of other many-nucleon removal reactions, further reinforcing the sequential nature of (p,3p) in neutron-rich nuclei.

Prominence of Pairing in Inclusive (p,2p) and (p,pn) Cross Sections from Neutron-Rich Nuclei.

Fifty-five inclusive single nucleon-removal cross sections from medium mass neutron-rich nuclei impinging on a hydrogen target at ∼250 MeV/nucleon are measured at the RIKEN Radioactive Isotope Beam Factory. Systematically higher cross sections are found for proton removal from nuclei with an even number of protons as compared to odd-proton number projectiles for a given neutron separation energy. Neutron removal cross sections display no even-odd splitting, contrary to nuclear cascade model predictions. Both effects are understood through simple considerations of neutron separation energies and bound state level densities originating in pairing correlations in the daughter nuclei. These conclusions are supported by comparison with semimicroscopic model predictions, highlighting the enhanced role of low-lying level densities in nucleon-removal cross sections from loosely bound nuclei.

Evidence for a new nuclear 'magic number' from the level structure of 54Ca.

Atomic nuclei are finite quantum systems composed of two distinct types of fermion--protons and neutrons. In a manner similar to that of electrons orbiting in an atom, protons and neutrons in a nucleus form shell structures. In the case of stable, naturally occurring nuclei, large energy gaps exist between shells that fill completely when the proton or neutron number is equal to 2, 8, 20, 28, 50, 82 or 126 (ref. 1). Away from stability, however, these so-called 'magic numbers' are known to evolve in systems with a large imbalance of protons and neutrons. Although some of the standard shell closures can disappear, new ones are known to appear. Studies aiming to identify and understand such behaviour are of major importance in the field of experimental and theoretical nuclear physics. Here we report a spectroscopic study of the neutron-rich nucleus (54)Ca (a bound system composed of 20 protons and 34 neutrons) using proton knockout reactions involving fast radioactive projectiles. The results highlight the doubly magic nature of (54)Ca and provide direct experimental evidence for the onset of a sizable subshell closure at neutron number 34 in isotopes far from stability.

Erratum: Persistence of the Z=28 Shell Gap Around

This corrects the article DOI: 10.1103/PhysRevLett.119.192501.

Gamma Decay of Unbound Neutron-Hole States in

Excited states in the nucleus ^{133}Sn, with one neutron outside the double magic ^{132}Sn core, were populated following one-neutron knockout from a ^{134}Sn beam on a carbon target at relativistic energies at the Radioactive Isotope Beam Factory at RIKEN. Besides the γ rays emitted in the decay of the known neutron single-particle states in ^{133}Sn additional γ strength in the energy range 3.5-5.5 MeV was observed for the first time. Since the neutron-separation energy of ^{133}Sn is low, S_{n}=2.402(4) MeV, this observation provides direct evidence for the radiative decay of neutron-unbound states in this nucleus. The ability of electromagnetic decay to compete successfully with neutron emission at energies as high as 3 MeV above threshold is attributed to a mismatch between the wave functions of the initial and final states in the latter case. These findings suggest that in the region southeast of ^{132}Sn nuclear structure effects may play a significant role in the neutron versus γ competition in the decay of unbound states. As a consequence, the common neglect of such effects in the evaluation of the neutron-emission probabilities in calculations of global ß-decay properties for astrophysical simulations may have to be reconsidered.

Persistence of the Z=28 Shell Gap Around

In-beam γ-ray spectroscopy of ^{79}Cu is performed at the Radioactive Isotope Beam Factory of RIKEN. The nucleus of interest is produced through proton knockout from a ^{80}Zn beam at 270 MeV/nucleon. The level scheme up to 4.6 MeV is established for the first time and the results are compared to Monte Carlo shell-model calculations. We do not observe significant knockout feeding to the excited states below 2.2 MeV, which indicates that the Z=28 gap at N=50 remains large. The results show that the ^{79}Cu nucleus can be described in terms of a valence proton outside a ^{78}Ni core, implying the magic character of the latter.

Low-Lying Structure of (50)Ar and the N=32 Subshell Closure.

The low-lying structure of the neutron-rich nucleus (50)Ar has been investigated at the Radioactive Isotope Beam Factory using in-beam γ-ray spectroscopy with (9)Be((54)Ca,(50)Ar+γ)X, (9)Be((55)Sc,(50)Ar+γ)X, and (9)Be((56)Ti,(50)Ar+γ)X multinucleon removal reactions at ∼220 MeV/u. A γ-ray peak at 1178(18) keV is reported and assigned as the transition from the first 2(+) state to the 0(+) ground state. A weaker, tentative line at 1582(38) keV is suggested as the 4(1)(+)→2(1)(+) transition. The experimental results are compared to large-scale shell-model calculations performed in the sdpf model space using the SDPF-MU effective interaction with modifications based on recent experimental data for exotic calcium and potassium isotopes. The modified Hamiltonian provides a satisfactory description of the new experimental results for (50)Ar and, more generally, reproduces the energy systematics of low-lying states in neutron-rich Ar isotopes rather well. The shell-model calculations indicate that the N=32 subshell gap in (50)Ar is similar in magnitude to those in (52)Ca and (54)Ti and, notably, predict an N=34 subshell closure in (52)Ar that is larger than the one recently reported in (54)Ca.

Extension of the N=40 Island of Inversion towards N=50: Spectroscopy of (66)Cr, (70,72)Fe.

We report on the measurement of the first 2(+) and 4(+) states of (66)Cr and (70,72)Fe via in-beam γ-ray spectroscopy. The nuclei of interest were produced by (p,2p) reactions at incident energies of 260 MeV/nucleon. The experiment was performed at the Radioactive Isotope Beam Factory, RIKEN, using the DALI 2γ-ray detector array and the novel MINOS device, a thick liquid hydrogen target combined with a vertex tracker. A low-energy plateau of 2(1)(+) and 4(1)(+) energies as a function of the neutron number was observed for N≥38 and N≥40 for even-even Cr and Fe isotopes, respectively. State-of-the-art shell model calculations with a modified Lenzi-Nowacki-Poves-Sieja (LNPS) interaction in the pfg(9/2)d(5/2) valence space reproduce the observations. Interpretation within the shell model shows an extension of the island of inversion at N=40 for more neutron-rich isotopes towards N=50.

Clinical and MRI features of Japanese patients with multiple sclerosis positive for NMO-IgG.

This study investigates the relation between the serological status of NMO (neuromyelitis optica)-IgG and the clinical and MRI features in Japanese patients with multiple sclerosis. Serum NMO-IgG was tested in 35 Japanese patients diagnosed with multiple sclerosis, including 19 with the optic-spinal form of multiple sclerosis (OSMS), three with the spinal form of multiple sclerosis (SMS), and 13 with the conventional form of multiple sclerosis (CMS), which affects the brain. NMO-IgG was detected in 14 patients, 12 with OSMS and 2 with CMS. In these patients, longitudinally extensive (> 3 vertebral segments) spinal cord lesions (93% v 57%) and permanent, complete blindness (no perception of light) in at least one eye (50% v 0%) were the noticeable features as compared with NMO-IgG-negative OSMS. The two patients having CMS with NMO-IgG had unusual brain lesions, but in other respects had features suggesting OSMS. NMO-IgG was detected in more than half the number of patients with OSMS and in some patients with CMS. This newly discovered serum autoantibody was markedly associated with longitudinally extensive spinal cord lesions and with complete blindness, suggesting severe optic-spinal disease.

Fatal hepatitis B virus reactivation in a chronic myeloid leukemia patient during imatinib mesylate treatment.

Reactivation of chronic hepatitis B virus (HBV) infection in patients undergoing chemotherapy is well-documented, but reactivation during imatinib mesylate treatment has not been reported. This study reports a 54-year-old man, without prior liver dysfunction but with chronic HBV infection, in whom fatal HBV reactivation occurred during treatment of chronic myeloid leukemia (CML) with imatinib mesylate. He developed fulminant hepatitis followed by marked elevation of HBV DNA polymerase, probably from the lymphocytopenic and immunosuppressive status induced by imatinib mesylate. Imatinib mesylate is widely used to treat CML patients. Although therapy with imatinib mesylate is generally well tolerated, the case presented here suggests that viral reactivation should be considered, even when using imatinib mesylate to treat CML.

A metal sulfide photocatalyst composed of ubiquitous elements for solar hydrogen production.

A visible-light-sensitive tin sulfide photocatalyst was designed based on a ubiquitous element strategy and density functional theory (DFT) calculations. Computational analysis suggested that tin monosulfide (SnS) would be more efficient than SnS2 as a photocathode for hydrogen production because of the low ionization potential and weak ionic character of SnS. To test this experimentally, nanoparticles of SnS were loaded onto a mesoporous electrode using a wet chemical method, and the bandgap of the synthesized SnS quantum dots was found to be tunable by adjusting the number of successive ionic layer adsorption and reaction (SILAR) cycles, which controls the magnitude of the quantum confinement effect. Efficient hydrogen production was achieved when the bandgap of SnS was wider than that of the bulk form.

Cloning and analysis of a cDNA encoding a two-domain hemoglobin chain from the water flea Daphnia magna.

A cDNA encoding a two-domain hemoglobin (Hb) chain of Daphnia magna was cloned and its nucleotide (nt) sequence of 1261 bp was determined. The nt sequence contained 74 bp of the leader sequence, 1047 bp of an open reading frame (ORF), and 119 bp of the 3'-untranslated region (UTR), excluding the polyadenylation tail. A sequence, AATACA, located 24 bp upstream from the polyA sequence was considered to be a polyadenylation signal. cDNA-derived amino acid (aa) sequence revealed that D. magna Hb chain is synthesized as a secretory precursor with a signal peptide of 18 aa. Mature D. magna Hb chain consists of 330-aa residues with a calculated molecular weight of 36227, which is composed of two large repeated domains, domain 1 and 2. Several key aa that are invariant in all or most of other Hb and required for functional heme-binding are conserved in each of the two domains. The N-terminal extension (pre-A segment) of domain 1 was unusually long and contained an unusual threonine-rich sequence. The homology between the aa sequences of the two domains (24% identity) was much lower than that observed in other two-domain Hb chains from clams or nematode. Hb mRNA level in D. magna reared under low oxygen concentration was more than 12 times higher than that in D. magna reared with sufficient aeration, indicating that the expression of Hb gene is regulated by mRNA level.

Mutation in the caveolin-3 gene causes a peculiar form of distal myopathy.

The authors describe a patient with sporadic distal myopathy associated with reduced caveolin-3 in muscle fibers in which the muscle atrophy was restricted to the small muscles of the hands and feet. Gene analysis disclosed a heterozygous 80 G-->A substitution in the caveolin-3 gene that was identical to that of reported cases of elevated serum creatine kinase. This patient further demonstrated possible clinical heterogeneity of myopathies with mutations in the caveolin-3 gene.

Epitope analysis of the cerebrospinal fluid IgG in HTLV-I associated myelopathy patients using phage display method.

We, for the first time, analyzed the binding motifs of immunoglobulin G (IgG) in the cerebrospinal fluid (CSF) of human T lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients with a phage library displaying 12-mer random peptides. As a result, the sequences highly homologous to HTLV-I gp46 192-199, 237-243 and 255-261 were the common linear epitopes of high affinity- IgG exclusively detected in both CSF and sera of the patients. These IgG responses were confirmed with corresponding HTLV-I peptides and serum antibody titers significantly correlated with disease severity or duration. Gp46 237-243 has not been detected in previous enzyme-linked immunosorbent assay (ELISA) studies using bound longer peptides, suggesting the usefulness of the phage display method.

Chromosome studies of hematopoietic colonies for distinct diagnosis of megakaryoblastic crisis of chronic myelogenous leukemia: a case report.

Chromosome studies of cells from megakaryocytic colonies (CFU-Meg) as evidenced by a megakaryocyte-specific monoclonal antibody, TP80, from a patient with chronic myelogenous leukemia (CML) in the blast crisis (BC) revealed the same aberrant karyotype, 52,XY,+9,+9,+18,+19,+21,+22,t(9;22)(q34;q11),t(9;22), as that having newly appeared in the peripheral blood. Cells from erythroid bursts (BFU-E) showed only the standard 46,XY,t(9;22) karyotype, and cells from granulocyte/macrophage colonies (CFU-GM) had either of these karyotypes. These results demonstrated that the whole megakaryocytic line and part of the granulocyte/macrophage line had been involved in the BC while the erythroid line totally belonged to the original clone. Chromosome analysis coupled with immunophenotyping of hemopoietic colonies was useful for a definite diagnosis of megakaryoblastic crisis of CML in this patient.

Escherichia coli phosphorylates 1,5-Anhydroglucitol and releases 1,5-Anhydroglucitol 6-phosphate when glucose is absent in the medium.

The cyclic polyol 1,5-anhydro-D-glucitol (AG) is detected in most organisms, but little is known about its metabolism and physiological roles. Our previous study demonstrated that Escherichia coli C600 synthesizes AG when glucose is exhausted in the medium and that it temporarily releases AG into and then takes it back from the medium, thus forming a sharp peak in AG concentration in the medium a few hours after reaching stationary growth phase. The present study demonstrates that when glucose is absent in the culture medium, E. coli C600 takes up and phosphorylates AG and releases a large portion of it back into the medium in the form of a phosphate ester. [U-13C]AG was added to the medium after the exhaustion of glucose and the resulting [U-13C]AG phosphate was partially purified by several steps of anion exchange chromatography and identified as AG 6-phosphate by 13C-NMR. The identity of the phosphate ester was also confirmed by GC-MS analysis after further purification.

NMR of all-carbon-13 sugars: an application in development of an analytical method for a novel natural sugar, 1,5-anhydrofructose.

Of the all-carbon-13 compounds, glucose is one of the most easily accessible, and therefore we applied 13C-NMR technique to the metabolic study of glucose-related compounds, 1,5-anhydro-D-glucitol and 1,5-anhydro-D-fructose (AF). Applying an INADEQUATE method to the substitutes of these novel sugars fully labeled with carbon-13, we could trace out the entire carbon skeleton with high sensitivity and confirm the chemical structures of these sugars. The method also provided a much easier way to optimize the enzymatic oxidation for AF preparation: we selectively and continuously monitored the quantities, as well as their structures in aqueous solution, of the substrate and products in a noninvasive manner. Similarly relying upon information from the 13C-NMR, we developed a valuable derivatization method of AF for its GC-MS application, which was so sensitive that we were able to demonstrate the natural occurrence of AF in rat liver.

1,5-Anhydroglucitol promotes glycogenolysis in Escherichia coli.

Glycogen is a storage compound that provides both carbon and energy, but the mechanism for the regulation of its metabolism has not been fully clarified. Recently, we found a new glycogenolytic pathway in rat liver in which glycogen is first metabolized to 1, 5-anhydrofructose (AnFru) and then to 1,5-anhydroglucitol (AnGlc-ol). Because the amounts of glycogen and AnFru are closely related in various rat organs and the second reaction, AnFru to AnGlc-ol, is strongly inhibited in the presence of glucose, we expected that this pathway might play a regulatory role in glycogen metabolism. Here we evaluate the expected involvement of AnGlc-ol and AnFru in the regulatory mechanism in Escherichia coli C600. Having established the presence of this new glycogenolytic pathway in E. coli C600, we further show that the conversion of AnFru to AnGlc-ol is activated only after the exhaustion of glucose in the medium, and that as little as 5 microM AnGlc-ol in the medium acutely accelerates the degradation of glycogen by 40%. We consider the role of AnGlc-ol in the mechanism that controls glycogen metabolism in E. coli to be as follows. When glucose is abundant, E. coli accumulate glycogen, a fraction of which is steadily degraded so that the amount of AnFru is about 1/1,000 of glycogen on a weight basis. When glucose is depleted and the demand for glycogen utilization is elevated, AnFru, which has accumulated mostly in the medium, is promptly taken up and converted to AnGlc-ol, which accelerates glycogen degradation. We also suggest the possibility that AnGlc-ol is one of the extracellular signaling molecules for bacteria.