Wide-field quantitative magnetic imaging of superconducting vortices using perfectly aligned quantum sensors

Various techniques have been applied to visualize superconducting vortices, providing clues to their electromagnetic response. Here, we present a wide-field, quantitative imaging of the stray field of the vortices in a superconducting thin film using perfectly aligned diamond quantum sensors. Our analysis, which mitigates the influence of the sensor inhomogeneities, visualizes the magnetic flux of single vortices in YBa$_2$Cu$_3$O$_{7-\delta}$ with an accuracy of $\pm10~\%$. The obtained vortex shape is consistent with the theoretical model, and penetration depth and its temperature dependence agree with previous studies, proving our technique's accuracy and broad applicability. This wide-field imaging, which in principle works even under extreme conditions, allows the characterization of various superconductors

Free fatty acid receptors, G protein-coupled receptor 120 and G protein-coupled receptor 40, are essential for oil-induced gastric inhibitory polypeptide secretion

Aims/Introduction: Incretin hormone glucose‐dependent insulinotropic polypeptide/gastric inhibitory polypeptide (GIP) plays a key role in high‐fat diet‐induced obesity and insulin resistance. GIP is strongly secreted from enteroendocrine K cells by oil ingestion. G protein‐coupled receptor (GPR)120 and GPR40 are two major receptors for long chain fatty acids, and are expressed in enteroendocrine K cells. In the present study, we investigated the effect of the two receptors on oil‐induced GIP secretion using GPR120‐ and GPR40‐double knockout (DKO) mice. Materials and Methods: Global knockout mice of GPR120 and GPR40 were crossbred to generate DKO mice. Oral glucose tolerance test and oral corn oil tolerance test were carried out. For analysis of the number of K cells and gene expression in K cells, DKO mice were crossbred with GIP‐green fluorescent protein knock‐in mice in which visualization and isolation of K cells can be achieved. Results: Double knockout mice showed normal glucose‐induced GIP secretion, but no GIP secretion by oil. We then investigated the number of K cells and gene characteristics in K cells isolated from GIP‐green fluorescent protein knock‐in mice. Deficiency of both receptors did not affect the number of K cells in the small intestine or expression of GIP messenger ribonucleic acid in K cells. Furthermore, there was no significant difference in the expression of the genes associated with lipid absorption or GIP secretion in K cells between wild‐type and DKO mice. Conclusions: Oil‐induced GIP secretion is triggered by the two major fatty acid receptors, GPR120 and GPR40, without changing K‐cell number or K‐cell characteristics

Phase Structure of a 3D Nonlocal U(1) Gauge Theory: Deconfinement by Gapless Matter Fields

In this paper, we study a 3D compact U(1) lattice gauge theory with a variety of nonlocal interactions that simulates the effects of gapless/gapful matter fields. This theory is quite important to investigate the phase structures of QED$_3$ and strongly-correlated electron systems like the 2D quantum spin models, the fractional quantum Hall effect, the t-J model of high-temperature superconductivity. We restrict the nonlocal interactions among gauge variables only to those along the temporal direction and adjust their coupling constants optimally to simulate the isotropic nonlocal couplings of the original models. We perform numerical studies of the model to find that, for a certain class of power-decaying couplings, there appears a second-order phase transition to the deconfinement phase as the gauge coupling constant is decreased. On the other hand, for the exponentially-decaying coupling, there are no signals for second-order phase transition. These results indicate the possibility that introduction of sufficient number of massless matter fields destabilizes the permanent confinement in the 3D compact U(1) pure gauge theory due to instantons.Comment: The version to be published in Nucl.Phys.

Ictal direct current shifts contribute to defining the core ictal focus in epilepsy surgery

難治てんかん焦点の新しいバイオマーカー「発作時DC電位」 --国内5施設の共同研究での世界初の成果--. 京都大学プレスリリース. 2022-09-05.Identifying the minimal and optimal epileptogenic area to resect and cure is the goal of epilepsy surgery. To achieve this, EEG analysis is recognized as the most direct way to detect epileptogenic lesions from spatiotemporal perspectives. Although ictal direct-current shifts (icDCs; below 1 Hz) and ictal high-frequency oscillations (icHFOs; above 80 Hz) have received increasing attention as good indicators that can add more specific information to the conventionally defined seizure-onset zone, large cohort studies on postoperative outcomes are still lacking. This work aimed to clarify whether this additional information, particularly icDCs which is assumed to reflect extracellular potassium concentration, really improve postoperative outcomes. To assess the usefulness in epilepsy surgery, we collected unique EEG datasets recorded with a longer time constant of 10 sec using an alternate current amplifier. 61 patients [15 with mesial temporal lobe epilepsy and 46 with neocortical epilepsy] who had undergone invasive presurgical evaluation for medically refractory seizures at five institutes in Japan, were retrospectively enrolled in this study. Among intracranially implanted electrodes, the two core electrodes of both icDCs and icHFOs were independently identified by board-certified clinicians based on unified methods. The occurrence patterns, such as their onset time, duration, and amplitude (power) were evaluated to extract the features of both icDCs and icHFOs. Additionally, we examined whether the resection ratio of the core electrodes of icDCs and icHFOs independently correlated with favorable outcomes. A total of 53 patients with 327 seizures were analyzed for wide-band EEG analysis, and 49 patients were analyzed for outcome analysis. icDCs were detected in the seizure-onset zone more frequently than icHFOs among both patients (92% vs. 71%) and seizures (86% vs. 62%). Additionally, icDCs significantly preceded icHFOs in patients exhibiting both biomarkers, and icDCs occurred more frequently in neocortical epilepsy patients than in mesial temporal lobe epilepsy patients. Finally, although a low corresponding rate was observed for icDCs and icHFOs (39%) at the electrode level, complete resection of the core area of icDCs significantly correlated with favorable outcomes, similar to icHFO outcomes. Our results provide a proof of concept that the independent significance of icDCs from icHFOs should be considered as reliable biomarkers to achieve favorable outcomes in epilepsy surgery. Moreover, the different distribution of the core areas of icDCs and icHFOs may provide new insights into the underlying mechanisms of epilepsy, in which not only neurons but also glial cells may be actively involved via extracellular potassium levels

Cyanobacterial Cell Lineage Analysis of the Spatiotemporal hetR Expression Profile during Heterocyst Pattern Formation in Anabaena sp. PCC 7120

Diazotrophic heterocyst formation in the filamentous cyanobacterium, Anabaena sp. PCC 7120, is one of the simplest pattern formations known to occur in cell differentiation. Most previous studies on heterocyst patterning were based on statistical analysis using cells collected or observed at different times from a liquid culture, which would mask stochastic fluctuations affecting the process of pattern formation dynamics in a single bacterial filament. In order to analyze the spatiotemporal dynamics of heterocyst formation at the single filament level, here we developed a culture system to monitor simultaneously bacterial development, gene expression, and phycobilisome fluorescence. We also developed micro-liquid chamber arrays to analyze multiple Anabaena filaments at the same time. Cell lineage analyses demonstrated that the initial distributions of hetR::gfp and phycobilisome fluorescence signals at nitrogen step-down were not correlated with the resulting distribution of developed heterocysts. Time-lapse observations also revealed a dynamic hetR expression profile at the single-filament level, including transient upregulation accompanying cell division, which did not always lead to heterocyst development. In addition, some cells differentiated into heterocysts without cell division after nitrogen step-down, suggesting that cell division in the mother cells is not an essential requirement for heterocyst differentiation