Performance of new Kuraray wavelength-shifting fibers with short decay time

We measure the decay time and the attenuation length of newly developed wavelength-shifting fibers, YS series from Kuraray, which have fast response. Using a 405 nm laser, the decay times of the YS-2, 4, and 6 are measured to be $3.70 \pm 0.04$ ns, $2.06 \pm 0.03$ ns, and $1.50 \pm 0.02$ ns, respectively. The decay time of Y-11 is measured to be $7.16 \pm 0.09$ ns using the same system. All fibers are found to have similar attenuation lengths of more than 4 meters. When combined with the plastic scintillators EJ-200 and EJ-204, the YS series have better time resolution than Y-11, with light yields of 60-100% of Y-11.Comment: 10 pages, 8 figure

Direct Damage to a Vertebral Artery Better Predicts a Vertebral Artery Injury than Elongation in Cervical Spine Dislocation

Cervical spine dislocation and fracture of a transverse process are isolated risk factors for vertebral artery injuries (VAIs), which can cause a life-threatening ischemic stroke. Since in vivo experiments are not possible, it has not been unclear whether damage to or extension of vertebral arteries is more predictive of a VAI. To identify the imaging characteristics associated with VAI, we analyzed 36 vertebral arteries from 22 cervical spine dislocation patients who underwent computed tomography angiography (Aug. 2008-Dec. 2014). We evaluated (1) the posttraumatic elongation of the vertebral artery and (2) the presence of fracture involving the transverse foramen. VAI was found in 20 (56%) of the 36 vertebral arteries. The rate of residual shift (vertebral artery elongation) was not markedly different between the VAI and no-VAI groups. However, the rate of >1 mm displacement into the foramen and that of fracture with gross displacement (≥2 mm) differed significantly between the groups. We found that greater displacement of fractured transverse processes with cervical spine dislocation was a risk factor for VAI. These results suggest that direct damage to the vertebral arteries by transverse process fragments is more likely to predict a VAI compared to elongation, even in cervical spine dislocation

Vibrational spectroscopy analysis of ligand efficacy in human M₂ muscarinic acetylcholine receptor (M₂R)

振動分光法を駆使した薬剤効能測定法の開発 --アセチルコリン受容体を標的とした神経疾患の治療薬開発への期待--. 京都大学プレスリリース. 2021-12-01.The intrinsic efficacy of ligand binding to G protein-coupled receptors (GPCRs) reflects the ability of the ligand to differentially activate its receptor to cause a physiological effect. Here we use attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy to examine the ligand-dependent conformational changes in the human M₂ muscarinic acetylcholine receptor (M₂R)). We show that different ligands affect conformational alteration appearing at the C=O stretch of amide-I band in M2R. Notably, ATR-FTIR signals strongly correlated with G-protein activation levels in cells. Together, we propose that amide-I band serves as an infrared probe to distinguish the ligand efficacy in M₂R) and paves the path to rationally design ligands with varied efficacy towards the target GPCR

Phytoceramide and sphingoid bases derived from brewer's yeast Saccharomyces pastorianus activate peroxisome proliferator-activated receptors

<p>Abstract</p> <p>Background</p> <p>Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that regulate lipid and glucose metabolism. PPARα is highly expressed in the liver and controls genes involved in lipid catabolism. We previously reported that synthetic sphingolipid analogs, part of which contains shorter-length fatty acid chains than natural sphingolipids, stimulated the transcriptional activities of PPARs. Sphingosine and dihydrosphingosine (DHS) are abundant sphingoid bases, and ceramide and dihydroceramide are major ceramide species in mammals. In contrast, phytosphingosine (PHS) and DHS are the main sphingoid bases in fungi. PHS and phytoceramide exist in particular tissues such as the epidermis in mammals, and involvement of ceramide species in PPARβ activation in cultured keratinocytes has been reported. The purpose of the present study is to investigate whether natural sphingolipids with C18 fatty acid and yeast-derived sphingoid bases activate PPARs as PPAR agonists.</p> <p>Method</p> <p>Lipids of brewer's yeast contain PHS- and DHS-based sphingolipids. To obtain the sphingoid bases, lipids were extracted from brewer's yeast and acid-hydrolyzed. The sphingoid base fraction was purified and quantified. To assess the effects of sphingolipids on PPAR activation, luciferase reporter assay was carried out. NIH/3T3 and human hepatoma (HepG2) cells were transfected with expression vectors for PPARs and retinoid × receptors, and PPAR responsive element reporter vector. When indicated, the PPAR/Gal4 chimera system was performed to enhance the credibility of experiments. Sphingolipids were added to the cells and the dual luciferase reporter assay was performed to determine the transcriptional activity of PPARs.</p> <p>Results</p> <p>We observed that phytoceramide increased the transcriptional activities of PPARs significantly, whereas ceramide and dihydroceramide did not change PPAR activities. Phytoceramide also increased transactivation of PPAR/Gal4 chimera receptors. Yeast-derived sphingoid base fraction, which contained PHS and DHS, or authentic PHS or DHS increased PPAR-dependent transcription. Additionally, phytoceramide stimulated PPARα activity in HepG2 hepatocytes, suggesting that phytoceramide activates genes regulated by PPARα.</p> <p>Conclusions</p> <p>Phytoceramide and yeast-derived sphingoid bases activate PPARs, whereas ceramide and dihydroceramide do not change the PPAR activity. The present findings suggest that phytoceramide acts as a PPAR ligand that would regulate PPAR-targeted genes.</p

The Atomic and Electronic structure of 0{\deg} and 60{\deg} grain boundaries in MoS2

We have investigated atomic and electronic structure of grain boundaries in monolayer MoS2, where relative angles between two different grains are 0 and 60 degree. The grain boundaries with specific relative angle have been formed with chemical vapor deposition growth on graphite and hexagonal boron nitride flakes; van der Waals interlayer interaction between MoS2 and the flakes restricts the relative angle. Through scanning tunneling microscopy and spectroscopy measurements, we have found that the perfectly stitched structure between two different grains of MoS2 was realized in the case of the 0 degree grain boundary. We also found that even with the perfectly stitched structure, valence band maximum and conduction band minimum shows significant blue shift, which probably arise from lattice strain at the boundary

X-ray magnetic circular dichroism and photoemission study of the diluted ferromagnetic semiconductor Zn1−x_{1-x}Crx_xTe

We have performed x-ray magnetic circular dichroism (XMCD) and valence-band photoemission studies of the diluted ferromagnetic semiconductor Zn$_{1-x}$Cr$_x$Te. XMCD signals due to ferromagnetism were observed at the Cr 2p absorption edge. Comparison with atomic multiplet calculations suggests that the magnetically active component of the Cr ion was divalent under the tetrahedral crystal field with tetragonal distortion along the crystalline a-, b-, and c-axes. In the valence-band spectra, spectral weight near the Fermi level was strongly suppressed, suggesting the importance of Jahn-Teller effect and the strong Coulomb interaction between the Cr 3d electrons

Relationship of Salivary Microbiome with the Worsening of the Periodontal Health Status in Young Adults: A 3-Year Cohort Study

The purpose of this prospective cohort study was to investigate the influence of the salivary microbiome on the worsening of the periodontal health status among Japanese young adults. We assessed the data of systemically healthy and non-smoking young (18-22 years) university students (n = 457) from Okayama University at baseline (2013) and follow-up (2016). The worsening group was defined based on an increase in the percentage of bleeding on probing (%BOP) or an increase in probing pocket depth (PPD) from = 4 mm. Unstimulated saliva samples were randomly collected from 69 students for microbiome analysis at follow-up. The salivary microbiome was assessed through 16S rRNA metagenomic sequencing. The type of community in the salivary microbiome clustered by statistical analysis and diversity was not significantly associated with the worsening of the periodontal health status in cases of increasing %BOP and PPD (p > 0.05). The prevalence of some species was significantly higher in the worsening group than in the non-worsening group (p < 0.05) in both cases. The worsening of the periodontal health status was associated with some species, but not the type of community and diversity in the salivary microbiome among Japanese young adults

Living with Family Is Directly Associated with Regular Dental Checkup and Indirectly Associated with Gingival Status among Japanese University Students: A 3-Year Cohort Study

Although some studies showed that lifestyle was associated with oral health behavior, few studies investigated the association between household type and oral health behavior. The aim of this prospective cohort study was to investigate the association between household type, oral health behavior, and periodontal status among Japanese university students. Data were obtained from 377 students who received oral examinations and self-questionnaires in 2016 and 2019. We assessed periodontal status using the percentage of bleeding on probing (%BOP), probing pocket depth, oral hygiene status, oral health behaviors, and related factors. We used structural equation modeling to determine the association between household type, oral health behaviors, gingivitis, and periodontitis. At follow-up, 252 students did not live with their families. The mean +/- standard deviation of %BOP was 35.5 +/- 24.7 at baseline and 32.1 +/- 25.3 at follow-up. In the final model, students living with their families were significantly more likely to receive regular dental checkup than those living alone. Regular checkup affected the decrease in calculus. The decrease in calculus affected the decrease in %BOP over 3 years. Living with family was directly associated with regular dental checkups and indirectly contributed to gingival status among Japanese university students