440 research outputs found

    The Most General and Renormalizable Maximal Abelian Gauge

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    We construct the most general gauge fixing and the associated Faddeev-Popov ghost term for the SU(2) Yang-Mills theory, which leaves the global U(1) gauge symmetry intact (i.e., the most general Maximal Abelian gauge). We show that the most general form involves eleven independent gauge parameters. Then we require various symmetries which help to reduce the number of independent parameters for obtaining the simpler form. In the simplest case, the off-diagonal part of the gauge fixing term obtained in this way is identical to the modified maximal Abelian gauge term with two gauge parameters which was proposed in the previous paper from the viewpoint of renormalizability. In this case, moreover, we calculate the beta function, anomalous dimensions of all fields and renormalization group functions of all gauge parameters in perturbation theory to one-loop order. We also discuss the implication of these results to obtain information on low-energy physics of QCD.Comment: 24 pages, 3 figure

    Low visual information-processing speed and attention are predictors of fatigue in elementary and junior high school students

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    Background: Fatigue is a common complaint among elementary and junior high school students, and is known to be associated with reduced academic performance. Recently, we demonstrated that fatigue was correlated with decreased cognitive function in these students. However, no studies have identified cognitive predictors of fatigue. Therefore, we attempted to determine independent cognitive predictors of fatigue in these students.Methods: We performed a prospective cohort study. One hundred and forty-two elementary and junior high school students without fatigue participated. They completed a variety of paper-and-pencil tests, including list learning and list recall tests, kana pick-out test, semantic fluency test, figure copying test, digit span forward test, and symbol digit modalities test. The participants also completed computerized cognitive tests (tasks A to E on the modified advanced trail making test). These cognitive tests were used to evaluate motor-and information-processing speed, immediate and delayed memory function, auditory and visual attention, divided and switching attention, retrieval of learned material, and spatial construction. One year after the tests, a questionnaire about fatigue (Japanese version of the Chalder Fatigue Scale) was administered to all the participants.Results: After the follow-up period, we confirmed 40 cases of fatigue among 118 students. In multivariate logistic regression analyses adjusted for grades and gender, poorer performance on visual information-processing speed and attention tasks was associated with increased risk of fatigue.Conclusions: Reduced visual information-processing speed and poor attention are independent predictors of fatigue in elementary and junior high school students

    Spectral Tuning Mechanism of Primate Blue-sensitive Visual Pigment Elucidated by FTIR Spectroscopy

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    Protein-bound water molecules are essential for the structure and function of many membrane proteins, including G-protein-coupled receptors (GPCRs). Our prior work focused on studying the primate green- (MG) and red- (MR) sensitive visual pigments using low-temperature Fourier transform infrared (FTIR) spectroscopy, which revealed protein-bound waters in both visual pigments. Although the internal waters are located in the vicinity of both the retinal Schiff base and retinal β-ionone ring, only the latter showed differences between MG and MR, which suggests their role in color tuning. Here, we report FTIR spectra of primate blue-sensitive pigment (MB) in the entire mid-IR region, which reveal the presence of internal waters that possess unique water vibrational signals that are reminiscent of a water cluster. These vibrational signals of the waters are influenced by mutations at position Glu113 and Trp265 in Rh, which suggest that these waters are situated between these two residues. Because Tyr265 is the key residue for achieving the spectral blue-shift in λmax of MB, we propose that these waters are responsible for the increase in polarity toward the retinal Schiff base, which leads to the localization of the positive charge in the Schiff base and consequently causes the blue-shift of λmax

    Physiological Properties of Rod Photoreceptor Cells in Green-sensitive Cone Pigment Knock-in Mice

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    Rod and cone photoreceptor cells that are responsible for scotopic and photopic vision, respectively, exhibit photoresponses different from each other and contain similar phototransduction proteins with distinctive molecular properties. To investigate the contribution of the different molecular properties of visual pigments to the responses of the photoreceptor cells, we have generated knock-in mice in which rod visual pigment (rhodopsin) was replaced with mouse green-sensitive cone visual pigment (mouse green). The mouse green was successfully transported to the rod outer segments, though the expression of mouse green in homozygous retina was ∼11% of rhodopsin in wild-type retina. Single-cell recordings of wild-type and homozygous rods suggested that the flash sensitivity and the single-photon responses from mouse green were three to fourfold lower than those from rhodopsin after correction for the differences in cell volume and levels of several signal transduction proteins. Subsequent measurements using heterozygous rods expressing both mouse green and rhodopsin E122Q mutant, where these pigments in the same rod cells can be selectively irradiated due to their distinctive absorption maxima, clearly showed that the photoresponse of mouse green was threefold lower than that of rhodopsin. Noise analysis indicated that the rate of thermal activations of mouse green was 1.7 × 10−7 s−1, about 860-fold higher than that of rhodopsin. The increase in thermal activation of mouse green relative to that of rhodopsin results in only 4% reduction of rod photosensitivity for bright lights, but would instead be expected to severely affect the visual threshold under dim-light conditions. Therefore, the abilities of rhodopsin to generate a large single photon response and to retain high thermal stability in darkness are factors that have been necessary for the evolution of scotopic vision

    First clinical assessment of [ 18 F]MC225, a novel fluorine-18 labelled PET tracer for measuring functional P-glycoprotein at the blood-brain barrier

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    Objective: 5-(1-(2-[18F]fluoroethoxy))-[3-(6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-propyl]-5,6,7,8-tetrahydronaphthalen ([18F]MC225) is a selective substrate for P-glycoprotein (P-gp), possessing suitable properties for measuring overexpression of P-gp in the brain. This is the first-in-human study to examine safety, radiation dosimetry and P-gp function at the blood-brain barrier (BBB) of [18F]MC225 in healthy subjects. Methods: [18F]MC225 biodistribution and dosimetry were determined in 3 healthy male subjects, using serial 2 h and intermittent 4 and 6 h whole-body PET scans acquired after [18F]MC225 injection. Dynamic [18F]MC225 brain PET (90 min) was obtained in 5 healthy male subjects. Arterial blood was sampled at various time intervals during scanning and the fraction of unchanged [18F]MC225 in plasma was determined. T1-weighted MRI was performed for anatomical coregistration. Total distribution volume (VT) was estimated using 1- and 2-tissue-compartment models (1-TCM and 2-TCM, respectively). VT was also estimated using the Logan graphical method (Logan plot) (t* = 20 min). Surrogate parameters without blood sampling (area-under the curve [AUC] of regional time-activity curves [TACs] and negative slope of calculated TACs) were compared with the VT values. Results: No serious adverse events occurred throughout the study period. Although biodistribution implied hepatobiliary excretion, secretion of radioactivity from liver to small intestine through the gallbladder was very slow. Total renal excreted radioactivity recovered during 6 h after injection was 0.9). AUCs of TACs were positively correlated with VT (2-TCM) values (r2: AUC0-60 min = 0.61, AUC0-30 min = 0.62, AUC30-60 min = 0.59, p < 0.0001). Negative slope of SUV TACs was negatively correlated with VT (2-TCM) values (r2 = 0.53, p < 0.0001). Conclusions: This initial evaluation indicated that [18F]MC225 is a suitable and safe PET tracer for measuring P-gp function at the BBB. Keywords: Blood–Brain barrier; Dosimetry; First-in-human; P-glycoprotein; Positron emission tomography

    FLASHING: New high-velocity H2_2O masers in IRAS 18286-0959

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    We discovered new high-velocity components of H2_2O maser emission in one of the "water fountain" sources, IRAS~18286-0959, which has been monitored using the Nobeyama 45 m telescope in the new FLASHING (Finest Legacy Acquisitions of SiO- and H2_2O-maser Ignitions by Nobeyama Generation) project since 2018 December. The maser spectra show new, extremely high expansion velocities (>>200~km~s1^{-1} projected in the line of sight) components, some of which are located symmetrically in the spectrum with respect to the systemic velocity. They were also mapped with KaVA (KVN and VERA Combined Array) in 2019 March. We located some of these maser components closer to the central stellar system than other high velocity components (50--200~km~s1^{-1}) that have been confirmed to be associated with the known bipolar outflow. The new components would flash in the fast collimated jet at a speed over 300~km~s1^{-1} (soon) after 2011 when they had not been detected. The fastest of the new components seem to indicate rapid deceleration in these spectra, however our present monitoring is still too sparse to unambiguously confirm it (up to 50~km~s1^{-1}yr1^{-1}) and too short to reveal their terminal expansion velocity, which will be equal to the expansion velocity that has been observed (vexpv_{\rm exp}\sim120~km~s1^{-1}). Future occurrences of such extreme velocity components may provide a good opportunity to investigate possible recurrent outflow ignitions. Thus sculpture of the parental envelope will be traced by the dense gas that is entrained by the fast jet and exhibits spectacular distributions of the relatively stable maser features.Comment: 11 pages, 5 figures, 2 table

    cDNA microarray analysis of bovine embryo gene expression profiles during the pre-implantation period

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    BACKGROUND: After fertilization, embryo development involves differentiation, as well as development of the fetal body and extra-embryonic tissues until the moment of implantation. During this period various cellular and molecular changes take place with a genetic origin, e.g. the elongation of embryonic tissues, cell-cell contact between the mother and the embryo and placentation. To identify genetic profiles and search for new candidate molecules involved during this period, embryonic gene expression was analyzed with a custom designed utero-placental complementary DNA (cDNA) microarray. METHODS: Bovine embryos on days 7, 14 and 21, extra-embryonic membranes on day 28 and fetuses on days 28 were collected to represent early embryo, elongating embryo, pre-implantation embryo, post-implantation extra-embryonic membrane and fetus, respectively. Gene expression at these different time points was analyzed using our cDNA microarray. Two clustering algorithms such as k-means and hierarchical clustering methods identified the expression patterns of differentially expressed genes across pre-implantation period. Novel candidate genes were confirmed by real-time RT-PCR. RESULTS: In total, 1,773 individual genes were analyzed by complete k-means clustering. Comparison of day 7 and day 14 revealed most genes increased during this period, and a small number of genes exhibiting altered expression decreased as gestation progressed. Clustering analysis demonstrated that trophoblast-cell-specific molecules such as placental lactogens (PLs), prolactin-related proteins (PRPs), interferon-tau, and adhesion molecules apparently all play pivotal roles in the preparation needed for implantation, since their expression was remarkably enhanced during the pre-implantation period. The hierarchical clustering analysis and RT-PCR data revealed new functional roles for certain known genes (dickkopf-1, NPM, etc) as well as novel candidate genes (AW464053, AW465434, AW462349, AW485575) related to already established trophoblast-specific genes such as PLs and PRPs. CONCLUSIONS: A large number of genes in extra-embryonic membrane increased up to implantation and these profiles provide information fundamental to an understanding of extra-embryonic membrane differentiation and development. Genes in significant expression suggest novel molecules in trophoblast differentiation

    FLASHING: Project Overview

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    This paper describes the overview of the FLASHING (Finest Legacy Acquisitions of SiO-/ H2_2O-maser Ignitions by the Nobeyama Generation) project promoted using the 45 m telescope of Nobeyama Radio Observatory, which aims to intensively monitor H2_2O (22 GHz) and SiO (43 GHz) masers associated with so-called "water fountain" sources. Here we show scientific results on the basis of the data taken in for the first five seasons of FLASHING, from 2018 December to 2023 April). We have found the evolution of the H2_2O maser spectra, such as new spectral components breaking the record of the jet's top speed and/or systematic velocity drifts in the spectrum indicating acceleration or deceleration of the maser gas clumps. For the 43 GHz SiO maser emission, we have found its new detection in a source while its permanent disappearance in other source. Our finding may imply that the jets from these water fountains can be accelerated or decelerated, and show how cicumstellar envelopes have been destroyed.Comment: 31 pages, 22 figures, to be published in the Publications of the Astronomical Society of Japa
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