Search for Tetraneutron by Pion Double Charge Exchange Reaction at J-PARC

Tetraneutron ($^4n$) has come back in the limelight, because of recent observation of a candidate resonant state at RIBF. We propose to investigate the pion double charge exchange (DCX) reaction, i.e. $^4\mathrm{He}({\pi}^- , {\pi}^+)$, as an alternative way to populate tetraneutron. An intense ${\pi}^-$ beam with the kinetic energy of ~850 MeV, much higher than that in past experiments at LAMPF and TRIUMF, will open up a possibility to improve the experimental sensitivity of the formation cross section, which will be much smaller than hitherto known DCX cross sections such as $^9\mathrm{Be}({\pi}^-, {\pi}^+)^9\mathrm{He}\ (g.s.)$.Comment: 4 pages, 1 figure; proceedings of the 14th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon (MENU2016), Kyoto, Japan, 25-30 July 201

(121,116)Sn中におけるπ中間子の深い束縛状態の精密分光

学位の種別: 課程博士審査委員会委員 : （主査）東京大学准教授 小沢 恭一郎, 東京大学特任教授 山下 了, 長崎総合科学生命大学教授 浜垣 秀樹, 東京大学 Lecturer Kathrin Wimmer, 理化学研究所主任研究員 初田 哲男University of Tokyo(東京大学

A new, simple method for quantifying gemcitabine triphosphate in cancer cells using isocratic high-performance liquid chromatography

A deoxycytidine analog, gemcitabine (dFdC), is effective for treating solid tumors and hematologic malignancies. After being transported into cancer cells, dFdC is phosphorylated to dFdC triphosphate (dFdCTP), which is subsequently incorporated into the DNA strand, thereby inhibiting DNA synthesis. Intracellular dFdCTP is the critical determinant for dFdC cytotoxicity, so therapeutic drug monitoring or in vitro testing of the capability of cancer cells to accumulate dFdCTP may be informative for optimizing dFdC administration. We have developed a new isocratic-elution HPLC method for quantifying dFdCTP in cancer cells. Samples (500 μl) were eluted isocratically using 0.06 M Na2HPO4 (pH = 6.9) containing 20% acetonitrile, at a constant flow rate of 0.7 ml/min and at ambient temperature. Separation was performed using an anion-exchange column, TSK gel DEAE-2SW (250 mm x 4.6 mm inside diameter, particle size 5 μl, TOSOH Corp.), and monitored at 254 nm. The standard curve was linear with low within-day and inter-day variability. The lower detection limit (20 pmol) was as sensitive as that of the previous gradient-elution method. dFdCTP was well separated from other nucleoside triphosphates. The method could measure dFdCTP in cultured or primary leukemic cells treated in vitro with dFdC. The method was also applicable to simultaneous determination of dFdCTP and cytarabine triphosphate, the results of which demonstrated the ara-CTP production augmented by the dFdC pretreatment. Thus, our isocratic HPLC assay method will be of great use because of its sensitivity and simplicity as well as its applicability to biological materials

Sensitivity of the deeply bound pionic atoms to the pion-nucleon sigma term σπN\sigma_{\pi N}

We discuss the sensitivity of the observables of the deeply bound pionic atoms to the pion-nucleon sigma term $\sigma_{\pi N}$ to investigate the possibility of the precise determination of the value of $\sigma_{\pi N}$ by the accurate data of the deeply bound pionic atoms expected to be obtained at RIBF/RIKEN. We evaluate that the 1 MeV variation of the $\sigma_{\pi N}$ value $\Delta \sigma_{\pi N} = 1$ MeV causes the shift of the binding energy $|\Delta B_\pi (1s)| = 5 \sim 7.5$ keV of the 1$s$ pionic atoms in Sn isotopes for the cases considered in this article. The width of the $1s$ state in the light Sn isotopes has good sensitivity to the $\sigma_{\pi N}$ value, too. We also study the sensitivity of the formation spectra of the deeply bound pionic atoms to the value of the $\sigma_{\pi N}$ term. The combined analyses of the observables of the deeply bound pionic atoms are found to be helpful to determine the $\sigma_{\pi N}$ term precisely. One of the interesting combination of the observables is the energy gap of the 1$s$ and $2p$ states ($B_{\pi}(1s) - B_\pi(2p)$) which experimental error is significantly smaller than that of the absolute value of the binding energy itself of each state. The expected experimental error of the energy gap is $10 \sim 15$ keV in Sn region which corresponds to the uncertainty of the $\sigma_{\pi N}$ value around 3 MeV in our evaluation.Comment: 9 pages, 8 figures, 3 table

Quantitative Estimation of Urate Transport in Nephrons in Relation to Urinary Excretion Employing Benzbromarone-Loading Urate Clearance Tests in Cases of Hyperuricemia

Background: A four-component system for urate transport in nephrons has been proposed and widely investigated by various investigators studying the mechanisms underlying urinary urate excretion. However, quantitative determinations of urate transport have not been clearly elucidated yet. Methods: The equation Cua = {Ccr(1 – R1) + TSR}(1 – R2) was designed to approximate mathematically urate transport in nephrons, where R1 = urate reabsorption ratio; R2 = urate postsecretory reabsorption ratio; TSR = tubular secretion rate; Cua = urate clearance, and Ccr = creatinine clearance . To investigate relationships between the three unknown variables (R1, R2, and TSR), this equation was expressed as contour lines of one unknown on a graph of the other two unknowns. Points at regular intervals on each contour line for the equation were projected onto a coordinate axis and the high-density regions corresponding to high-density intervals of a coordinate were investigated for three graph types. For benzbromarone (BBR)-loading Cua tests, Cua was determined before and after oral administration of 100 mg of BBR and CuaBBR(∞) was calculated from the ratio of CuaBBR(100)/Cua. Results: Before BBR administration, points satisfying the equation on the contour line for R1 = 0.99 were highly dense in the region R2 = 0.87–0.92 on all three graphs, corresponding to a TSR of 40–60 ml/min in hyperuricemia cases (HU). After BBR administration, the dense region was shifted in the direction of reductions in both R1 and R2, but TSR was unchanged. Under the condition that R1 = 1 and R2 = 0, urate tubular secretion (UTS) was considered equivalent to calculated urinary urate excretion (Uex) in a model of intratubular urate flow with excess BBR; CuaBBR(∞) = TSR was deduced from the equation at R1 = 1 and R2 = 0. In addition, TSR of the point under the condition that R1 = 1 and R2 = 0 on the graph agreed with TSR for the dense region at excess BBR. TSR was thus considered approximately equivalent to CuaBBR(∞), which could be determined from a BBR-loading Cua test. Approximate values for urate glomerular filtration, urate reabsorption, UTS, urate postsecretory reabsorption (UR2), and Uex were calculated as 9,610; 9,510; 4,490; 4,150, and 440 µg/min for HU and 6,890; 6,820; 4,060; 3,610, and 520 µg/min for normal controls (NC), respectively. The most marked change in HU was the decrease in TSR (32.0%) compared to that in NC, but UTS did not decrease. Calculated intratubular urate contents were reduced more by higher UR2 in HU than in NC. This enhanced difference resulted in a 15.4% decrease in Uex for HU. Conclusion: Increased UR2 may represent the main cause of urate underexcretion in HU

Effect of Propagation Signal and Path on Verification Performance Using Intra-Body Propagation Signals

Biometrics is the verification or the identification method of users by measuring and analyzing their biometric data, which is only applicable to continuous authentication in a system. In particular, unconsciously presentable biometric modalities are also applicable to an authentication system. As such a biometrics, to use intra-body propagation signals that propagate on a body surface as electromagnetic waves have been proposed. In conventional approaches, verification performance on palms has been evaluated by a white signal as a propagation signal. In this paper, it is reported that the effects of using a synthesized signal by sinusoidal waves with fixed amplitudes and phases instead of the white signal and propagating this signal on other body parts on verification