Stochastic extension of the Lanczos method for nuclear shell-model calculations with variational Monte Carlo method

We propose a new variational Monte Carlo (VMC) approach based on the Krylov subspace for large-scale shell-model calculations. A random walker in the VMC is formulated with the $M$-scheme representation, and samples a small number of configurations from a whole Hilbert space stochastically. This VMC framework is demonstrated in the shell-model calculations of $^{48}$Cr and $^{60}$Zn, and we discuss its relation to a small number of Lanczos iterations. By utilizing the wave function obtained by the conventional particle-hole-excitation truncation as an initial state, this VMC approach provides us with a sequence of systematically improved results.Comment: 5 pages, 4 figures, submitted to Physics Letters

Rotation alignment in neutron-rich Cr isotopes: A probe of deformed single-particle levels across N=40

Recent experiments have reached the neutron-rich Cr isotope with N=40 and confirmed enhanced collectivity near this sub-shell. The current data focus on low-spin spectroscopy only, with little information on the states where high-j particles align their spins with the system rotation. By applying the Projected Shell Model, we show that rotation alignment occurs in neutron-rich even-even Cr nuclei as early as spin 8 and, due to shell filling, the aligning particles differ in different isotopes. It is suggested that observation of irregularities in moments of inertia is a direct probe of the deformed single-particle scheme in this exotic mass region.Comment: 6 pages, 5 figures, accepted for publication in Phys. Rev.

Small for Gestational Age and Magnesium in Cord Blood Platelets: Intrauterine Magnesium Deficiency May Induce Metabolic Syndrome in Later Life

Magnesium deficiency in pregnancy frequently occurs because of inadequate or low intake of magnesium. Magnesium deficiency during pregnancy can induce not only maternal and fetal nutritional problems, but also consequences that might last in offspring throughout life. Many epidemiological studies have disclosed that small for gestational age (SGA) is associated with an increased risk of insulin resistance in adult life. We reported that intracellular magnesium of cord blood platelets is lower in SGA groups than that in appropriate for gestational age groups, suggesting that intrauterine magnesium deficiency may result in SGA. Taken together, intrauterine magnesium deficiency in the fetus may lead to or at least program insulin resistance after birth. In this review, we propose that intrauterine magnesium deficiency may induce metabolic syndrome in later life. We discuss the potential contribution of aberrant magnesium regulation to SGA and to the pathogenesis of metabolic syndrome

Shell gaps and pn pairing interaction in N = Z nuclei

We analyze the observed shell gaps in N=Z nuclei determined from the binding energy differences. It is found that the shell gaps can be described by the combined contributions from the single-particle level spacing, the like-nucleon pairing, and the proton-neutron pairing interaction. This conclusion is consistent with that of Chasman in Phys. Rev. Lett. 99 (2007) 082501. For the double-closed shell N=Z nuclei, the single-particle level spacings calculated with Woods-Saxon potential are very close to those obtained by subtracting the nn pairing interaction from the observed shell gap. For the sub-closed or non-closed shell N=Z nuclei, the pn pairing interaction is shown to be important for the observed shell gaps.Comment: 9 pages, 5 figure

Shell model study for neutron-rich sd-shell nuclei

The microscopic structure of neutron-rich sd-shell nuclei is investigated by using the spherical shell-model in the sd-pf valence space with the extended pairing plus quadrupole-quadrupole forces accompanied by the monopole interaction (EPQQM). The calculation reproduces systematically the known energy levels for even-even and odd-mass nuclei including the recent data for 43S, 46S and 47Ar. In particular, the erosion of the N=28 shell closure in 42Si can be explained. Our EPQQM results are compared with other shell-model calculations with the SDPF-NR and SDPF-U effective interactions.Comment: 7 pages, 10 figures, accepted for publication in Phys. Rev.

Application of Long-Range Surface Plasmon Resonance for ABO Blood Typing

In this study, we demonstrate a long-range surface plasmon resonance (LR-SPR) biosensor for the detection of whole cell by captured antigens A and B on the surface of red blood cells (RBCs) as a model. The LR-SPR sensor chip consists of high-refractive index glass, a Cytop film layer, and a thin gold (Au) film, which makes the evanescent field intensity and the penetration depth longer than conventional SPR. Therefore, the LR-SPR biosensor has improved capability for detecting large analytes, such as RBCs. The antibodies specific to blood group A and group B (Anti-A and Anti-B) are covalently immobilized on a grafting self-assembled monolayer (SAM)/Au surface on the biosensor. For blood typing, RBC samples can be detected by the LR-SPR biosensor through a change in the refractive index. We determined that the results of blood typing using the LR-SPR biosensor are consistent with the results obtained from the agglutination test. We obtained the lowest detection limits of 1.58 × 105 cells/ml for RBC-A and 3.83 × 105 cells/ml for RBC-B, indicating that the LR-SPR chip has a higher sensitivity than conventional SPR biosensors (3.3 × 108 cells/ml). The surface of the biosensor can be efficiently regenerated using 20 mM NaOH. In summary, as the LR-SPR technique is sensitive and has a simple experimental setup, it can easily be applied for ABO blood group typing

Urinary sludge caused by ceftriaxone in a young boy

It is known that ceftriaxone administration is associated with biliary pseudolithiasis, although the development of urolithiasis has been rarely reported. We encountered a young male with bacterial meningitis complicated by urinary precipitates composed of ceftriaxone-calcium salt which is confirmed by high-performance liquid chromatography. This patient suggested that ceftriaxone significantly increased urinary excretion of calcium, which may be linked to ceftriaxone-related urolithiasis or sludge. It is therefore worthwhile to monitor the levels of urinary calcium to creatinine ratio in patients on ceftriaxone, as they may be at greater risk for developing large stones and renal damage