Ultrabright narrow-band telecom two-photon source for long-distance quantum communication

We demonstrate an ultrabright narrow-band two-photon source at the 1.5 -\mu m telecom wavelength for long-distance quantum communication. By utilizing a bow-tie cavity, we obtain a cavity enhancement factor of $4.06\times 10^4$. Our measurement of the second-order correlation function $G^{(2)} ({\tau})$ reveals that the linewidth of $2.4$ MHz has been hitherto unachieved in the 1.5 -\mu m telecom band. This two-photon source is useful for obtaining a high absorption probability close to unity by quantum memories set inside quantum repeater nodes. Furthermore, to the best of our knowledge, the observed spectral brightness of $3.94\times 10^5$ pairs/(s$\cdot$MHz$\cdot$mW) is also the highest reported over all wavelengths.Comment: 11 pages, 4 figures, 2 table

The influence of rhein 8-O-β-D-glucopyranoside on the purgative action of sennoside A from rhubarb in mice.

Rhubarb is one of the most well-known herbal medicines that constitute daiokanzoto (DKT), which is clinically effective for constipation. Sennoside A is transformed into an active metabolite, rheinanthrone, by intestinal bacteria. Sennoside A in rhubarb showed significantly accelerated metabolic activity in intestinal bacteria in comparison with sennoside A alone. In this study, we investigated the influence of rhubarb constituents on the metabolism and purgative activity of sennoside A. The 20% MeOH-eluted fraction separated by MCI-gel CHP-20P column chromatography from the water extract of rhubarb showed sennoside A metabolic activity similar to that of rhubarb extract. The 20% MeOH elute was further purified and rhein 8-O-β-D-glucopyranoside (RG) was isolated. The metabolic activity of sennoside A was significantly accelerated by increasing the level of RG. Moreover, rhein, emodin and aloe-emodin also accelerated sennoside A metabolism. The purgative activity of sennoside A was significantly accelerated when RG or rhein was concomitantly given with sennoside A in a dose-dependent manner. These results suggest that anthraquinones contribute to the purgative action of sennoside A in rhubarb. Therefore, it is assumed that the influence of anthraquinones on the fate of rheinanthrone transformed from sennoside A may promote the purgative action of sennoside A.Rhubarb is one of the most well-known herbal medicines that constitute daiokanzoto (DKT), which is clinically effective for constipation. Sennoside A is transformed into an active metabolite, rheinanthrone, by intestinal bacteria. Sennoside A in rhubarb showed significantly accelerated metabolic activity in intestinal bacteria in comparison with sennoside A alone. In this study, we investigated the influence of rhubarb constituents on the metabolism and purgative activity of sennoside A. The 20% MeOH-eluted fraction separated by MCI-gel CHP-20P column chromatography from the water extract of rhubarb showed sennoside A metabolic activity similar to that of rhubarb extract. The 20% MeOH elute was further purified and rhein 8-O-β-D-glucopyranoside (RG) was isolated. The metabolic activity of sennoside A was significantly accelerated by increasing the level of RG. Moreover, rhein, emodin and aloe-emodin also accelerated sennoside A metabolism. The purgative activity of sennoside A was significantly accelerated when RG or rhein was concomitantly given with sennoside A in a dose-dependent manner. These results suggest that anthraquinones contribute to the purgative action of sennoside A in rhubarb. Therefore, it is assumed that the influence of anthraquinones on the fate of rheinanthrone transformed from sennoside A may promote the purgative action of sennoside A

The influence of glycyrrhiza and antibiotics on the purgative action of sennoside A from Daiokanzoto in mice.

Daiokanzoto (DKT), a Kampo medicine that includes the combination of two crude drugs (rhubarb and glycyrrhiza), is clinically effective for constipation. The aim of this study is to clarify the influence of glycyrrhiza, three glycyrrhiza constituents (glycyrrhizin, liquiritin, and liquiritin apioside), and eight antibiotics on the purgative action of DKT, rhubarb, or sennoside A, a constituent of rhubarb, in mice. The purgative actions of rhubarb and sennoside A were significantly intensified when glycyrrhiza was co-administered orally to mice. Liquiritin and liquiritin apioside but not glycyrrhizin showed significant amplification of the purgative action in a dose-dependent manner. The purgative actions of DKT and sennoside A were significantly reduced by the pre-administration of ampicillin, cefcapene pivoxil, faropenem, fosfomycin, or kanamycin, but were not affected by the pre-administration of clarithromycin or levofloxacin. On the other hand, the purgative action of sennoside A was significantly reduced by the pre-administration of minocycline, whereas that of DKT was not affected. The effect of minocycline on the purgative action of sennoside A was lost when glycyrrhiza was co-administered. These results suggest that liquiritin and liquiritin apioside contribute as active substances for the purgative action of DKT, and some antibiotics reduce the purgative action of DKT and sennoside A. Furthermore, glycyrrhiza has the ability to recover the purgative action of sennoside A suppressed by minocycline via an unknown mechanism.Daiokanzoto (DKT), a Kampo medicine that includes the combination of two crude drugs (rhubarb and glycyrrhiza), is clinically effective for constipation. The aim of this study is to clarify the influence of glycyrrhiza, three glycyrrhiza constituents (glycyrrhizin, liquiritin, and liquiritin apioside), and eight antibiotics on the purgative action of DKT, rhubarb, or sennoside A, a constituent of rhubarb, in mice. The purgative actions of rhubarb and sennoside A were significantly intensified when glycyrrhiza was co-administered orally to mice. Liquiritin and liquiritin apioside but not glycyrrhizin showed significant amplification of the purgative action in a dose-dependent manner. The purgative actions of DKT and sennoside A were significantly reduced by the pre-administration of ampicillin, cefcapene pivoxil, faropenem, fosfomycin, or kanamycin, but were not affected by the pre-administration of clarithromycin or levofloxacin. On the other hand, the purgative action of sennoside A was significantly reduced by the pre-administration of minocycline, whereas that of DKT was not affected. The effect of minocycline on the purgative action of sennoside A was lost when glycyrrhiza was co-administered. These results suggest that liquiritin and liquiritin apioside contribute as active substances for the purgative action of DKT, and some antibiotics reduce the purgative action of DKT and sennoside A. Furthermore, glycyrrhiza has the ability to recover the purgative action of sennoside A suppressed by minocycline via an unknown mechanism

Imaging Protein Misfolding in the Brain Using β-Sheet Ligands

Neurodegenerative diseases characterized by pathological protein accumulation in cells are termed “proteinopathies.” Although various protein aggregates share cross-β-sheet structures, actual conformations vary among each type of protein deposit. Recent progress in the development of radiotracers for positron emission tomography (PET) has enabled the visualization of protein aggregates in living brains. Amyloid PET tracers have been developed, and are widely used for the diagnosis of Alzheimer’s disease and non-invasive assessment of amyloid burden in clinical trials of anti-dementia drugs. Furthermore, several tau PET tracers have been successfully developed and used in the clinical studies. However, recent studies have identified the presence of off-target binding of radiotracers in areas of tau deposition, suggesting that concomitant neuroinflammatory changes might affect tracer binding. In contrast to amyloid and tau PET, there are no established tracers for imaging Lewy bodies in the human brain. In this review, we describe lessons learned from the development of PET tracers and discuss the future direction of tracer development for protein misfolding diseases

マウス糞便を用いた大黄甘草湯中のセンノシドA腸内代謝とHPLC定量分析(発表論文抄録(2011))

Daiokanzoto (DKT, combination of rhubarb and glycyrrhiza), a Kampo medicine, is clinically effective for constipation. Sennoside A is well known to induce diarrhea. Sennoside A is a prodrug that is transformed into an active metabolite, rheinanthrone, by intestinal bacteria. In this study, we investigated the effects of glycyrrhiza on the activity of sennoside A metabolism in intestinal bacteria using mouse feces. A high-performance liquid chromatography (HPLC) method for the determination of sennoside A in incubation mixture of DKT with mouse feces was established. The retention time of sennoside A was 9.26±0.02 min with a TSKgel ODS-80TsQA column by linear gradient elution using a mobile phase containing aqueous phosphoric acid and acetonitrile and detection at 265 nm. We found that the activity of sennoside A metabolism in intestinal bacteria was significantly accelerated when glycyrrhiza, liquiritin or liquiritin apioside coexisted with sennoside A, whereas that of glycyrrhizin was not altered. This method is applicable for determination of the activity of sennoside A metabolism by anaerobic incubation of DKT with mouse feces.Daiokanzoto (DKT, combination of rhubarb and glycyrrhiza), a Kampo medicine, is clinically effective for constipation. Sennoside A is well known to induce diarrhea. Sennoside A is a prodrug that is transformed into an active metabolite, rheinanthrone, by intestinal bacteria. In this study, we investigated the effects of glycyrrhiza on the activity of sennoside A metabolism in intestinal bacteria using mouse feces. A high-performance liquid chromatography (HPLC) method for the determination of sennoside A in incubation mixture of DKT with mouse feces was established. The retention time of sennoside A was 9.26±0.02 min with a TSKgel ODS-80TsQA column by linear gradient elution using a mobile phase containing aqueous phosphoric acid and acetonitrile and detection at 265 nm. We found that the activity of sennoside A metabolism in intestinal bacteria was significantly accelerated when glycyrrhiza, liquiritin or liquiritin apioside coexisted with sennoside A, whereas that of glycyrrhizin was not altered. This method is applicable for determination of the activity of sennoside A metabolism by anaerobic incubation of DKT with mouse feces

Dissociation of Tau Deposits and Brain Atrophy in Early Alzheimer’s Disease: A Combined Positron Emission Tomography/Magnetic Resonance Imaging Study

The recent advent of tau-specific positron emission tomography (PET) has enabled in vivo assessment of tau pathology in Alzheimer’s disease (AD). However, because PET scanners have limited spatial resolution, the measured signals of small brain structures or atrophied areas are underestimated by partial volume effects (PVEs). The aim of this study was to determine whether partial volume correction (PVC) improves the precision of measures of tau deposits in early AD. We investigated tau deposits in 18 patients with amyloid-positive early AD and in 36 amyloid-negative healthy controls using 18F-THK5351 PET. For PVC, we applied the SPM toolbox PETPVE12. The PET images were then spatially normalized and subjected to voxel-based group analysis using SPM12 for comparison between the early AD patients and healthy controls. We also compared these two groups in terms of brain atrophy using voxel-based morphometry of MRI. We found widespread neocortical tracer retention predominantly in the posterior cingulate and precuneus areas, but also in the inferior temporal lobes, inferior parietal lobes, frontal lobes, and occipital lobes in the AD patients compared with the controls. The pattern of tracer retention was similar between before and after PVC, suggesting that PVC had little effect on the precision of tau load measures. Gray matter atrophy was detected in the medial/lateral temporal lobes and basal frontal lobes in the AD patients. Interestingly, only a few associations were found between atrophy and tau deposits, even after PVC. In conclusion, PVC did not significantly affect 18F-THK5351 PET measures of tau deposits. This discrepancy between tau deposits and atrophy suggests that tau load precedes atrophy