Anomalous behavior of the energy gap in the one-dimensional quantum XY model

We re-examine the well-studied one dimensional spin-1/2 $XY$ model to reveal its nontrivial energy spectrum, in particular the energy gap between the ground state and the first excited state. In the case of the isotropic $XY$ model -- the $XX$ model -- the gap behaves very irregularly as a function of the system size at a second order transition point. This is in stark contrast to the usual power-law decay of the gap and is reminiscent of the similar behavior at the first order phase transition in the infinite-range quantum $XY$ model. The gap also shows nontrivial oscillatory behavior for the phase transitions in the anisotropic model in the incommensurate phase. We observe a close relation between this anomalous behavior of the gap and the correlation functions. These results, those for the isotropic case in particular, are important from the viewpoint of quantum annealing where the efficiency of computation is strongly affected by the size dependence of the energy gap.Comment: 25 pages, 8 figures. arXiv admin note: substantial text overlap with arXiv:1501.0292

Hydrophilic and Hydrophobic Compounds Antithetically Affect the Growth of Eicosapentaenoic Acid-Synthesizing Escherichia coli Recombinants

The growth of Escherichia coli DH5α recombinants producing eicosapentaenoic acid (EPA) (DH5αEPA+) and those not producing EPA (DH5αEPA–) was compared in the presence of hydrophilic or hydrophobic growth inhibitors. The minimal inhibitory concentrations of hydrophilic inhibitors such as reactive oxygen species and antibiotics were higher for DH5αEPA+ than for DH5αEPA–, and vice versa for hydrophobic inhibitors such as protonophores and radical generators. E. coli DH5α with higher levels of EPA became more resistant to ethanol. The cell surface hydrophobicity of DH5αEPA+ was higher than that of DH5αEPA–, suggesting that EPA may operate as a structural constituent in the cell membrane to affect the entry and efflux of hydrophilic and hydrophobic inhibitors

Elevated Soluble PD-L1 in Pregnant Women's Serum Suppresses the Immune Reaction

Background: Programmed death-ligand 1 (PD-L1) is expressed not only on some cancer cells, but also on the outer surface of placental syncytiotrophoblasts, which is assumed to induce maternal immune tolerance to fetal tissue via programmed death-1 (PD-1) receptors on T cells. Recently, levels of soluble forms of PD-L1 (sPD-L1) were reported to be higher in the serum of pregnant women (PW) than in non-pregnant women (non-PW). However, there have been no reports of the functional significance of PW's serum containing high sPD-L1 levels. Therefore, the aim of the present study was to clarify the role of sPD-L1 in the sera of PW as an immunosuppressive molecule by in vitro assays.Methods: As a post-hoc analysis of our previous cohort study, 330 pairs of serum from PW during the third trimester and cord blood (CB) from paired offspring without major complications were examined. Serum levels of sPD-L1 and sPD-1 were measured by ELISA. On mixed lymphocyte culture (MLC), 3H-thymidine uptakes in the presence of PW's, offspring's, or non-PW's serum were compared. Peripheral blood mononuclear cells (PBMCs) were cultured in the presence of PW's serum stimulated with PHA, and then cytokine levels were measured in supernatants by multiple cytokine analysis with or without anti-PD-L1blocking antibody.Results: The median sPD-L1 level was 8.3- and 6.9-fold higher in PW than in offspring and non-PW, respectively, whereas sPD-1 levels were lower in PW and offspring than in non-PW. On MLC, 3H-thymidine uptake in the presence of autoantigen was strongly reduced by co-culture with serum of both PW and offspring, compared with serum of non-PW. In contrast, uptake in the presence of alloantigen was moderately inhibited by PW's serum, whereas it was less suppressed by offspring's serum, compared with non-PW's serum. In the culture of PBMCs, tumor necrosis factor-α, interferon gamma, interleukin (IL)-2, and IL-4 levels were significantly higher in the presence of anti-PD-L1 blocking antibody than in culture not treated with antibody (all P < 0.05) or culture treated with isotype control antibody (all P < 0.05).Conclusion: The levels of sPD-L1 are elevated in PW's serum, which may, at least in part, suppress maternal immunity

Both the anaerobic pathway and aerobic desaturation are involved in the synthesis of unsaturated fatty acids in Vibrio sp. strain ABE-1

AbstractVibrio sp. strain ABE-1 is a unique marine bacterium in terms of its ability to synthesize Δ9-trans-hexadecenoic acid and Δ7-cis-tetradecenoic acid (14:1(7c); Okuyama, H., Sasaki, S., Higashi, S. and Murata, N. (1990) J. Bacteriol. 172, 3515-3518). The present study, involving labeling with [1-14C]acetate, demonstrated that 14:1 is synthesized by the anaerobic pathway. When cells of this bacterium were grown in the presence of [1-14C]myristic acid (14:0), this compound was converted to palmitic (16:0) and hexadecenoic (16:1) acids but not to 14:1, under aerobic conditions. These results suggest that the incorporated 14:0 was elongated to 16:0 and then converted to 16:1 by the aerobic desaturation of 16:0. It appears that the anaerobic pathway and aerobic desaturation are both involved in the synthesis of unsaturated fatty acids during aerobic growth of Vibrio sp. strain ABE-1

The Escherichia coli highly expressed entD gene complements the pfaE deficiency in a pfa gene clone responsible for the biosynthesis of long-chain n-3 polyunsaturated fatty acids

The Escherichia coli entD gene, which encodes an Sfp-type phosphopantetheinyl transferase (PPTase) that is involved in the biosynthesis of siderophore, is available as a high-expression ASKA clone (pCA24N::entD) constructed from the E. coli K-12 strain AG1. In E. coli DH5α, pCA24N::entD complemented a pfaE-deficient clone that comprised pfaA, pfaB, pfaC and pfaD, which are four of the five pfa genes that are responsible for the biosynthesis of eicosapentaenoic acid derived from Shewanella pneumatophori SCRC-2738. Sfp-type PPTases are classified into the EntD and PfaE groups, based on differences between their N-terminal-domain structures. Here, we showed that all Sfp-type PPTases may have the potential to promote the biosynthesis of long-chain n-3 polyunsaturated fatty acids

Lipids of psychrophilic and psychrotrophic bacteria, previous and current perspectives

第3回極域科学シンポジウム/第34回極域生物シンポジウム 11月27日（火） 国立極地研究所 ３階ラウン

Community structures of crude-oil degrading bacteria in seacoasts of Hokkaido

第2回極域科学シンポジウム/第33回極域生物シンポジウム 11月17日（木） 統計数理研究所 3階リフレッシュフロ

Autochthonous augmentation to crude-oil contamination in Hokkaido

第2回極域科学シンポジウム/第33回極域生物シンポジウム 11月17日（木） 統計数理研究所 3階リフレッシュフロ

The novel function of eicosapentaenoic acid in bacterial cell membranes

第2回極域科学シンポジウム/第33回極域生物シンポジウム 11月17日（木） 統計数理研究所 3階リフレッシュフロ