Search

We performed a novel Σ⁺+p scattering experiment at the J-PARC Hadron Experimental Facility. Approximately 2400 Σ⁺+p elastic scattering events were identified from 4.9 × 10⁷ tagged Σ⁺+ particles in the Σ⁺+ momentum range 0.44-0.80 GeV/c. The differential cross sections of the Σ⁺+p elastic scattering were derived with much better precision than in previous experiments. The obtained differential cross sections were approximately 2 mb/sr or less, which were not as large as those predicted by the fss2 and FSS models based on the quark cluster model in the short-range region. By performing phase-shift analyses for the obtained differential cross sections, we experimentally derived the phase shifts of the ³S₁ and ¹P₁ channels for the first time. The phase shift of the ³S₁ channel, where a large repulsive core was predicted owing to the Pauli effect between quarks, was evaluated as 20° < |δ₃S₁| < 35°. If the sign of δ₃S₁ is assumed to be negative, the interaction in this channel is moderately repulsive, as the Nijmegen extended-sort-core models predicted., クォーク間の「芯」をとらえた --物質が安定して存在できる理由の理解に貢献--. 京都大学プレスリリース. 2022-09-05.

We performed a novel $Σ^+ p$ scattering experiment at the J-PARC Hadron Experimental Facility. Approximately 2400 $Σ^+ p$ elastic scattering events were identified from $4.9 \times 10^7$ tagged $Σ^+$ particles in the $Σ^+$ momentum range 0.44 -- 0.80 GeV/$c$. The differential cross sections of the $Σ^+ p$ elastic scattering were derived with much better precision than in previous experiments. The obtained differential cross sections were approximately 2 mb/sr or less, which were not as large as those predicted by the fss2 and FSS models based on the quark cluster model in the short-range region. By performing phase-shift analyses for the obtained differential cross sections, we experimentally derived the phase shifts of the $^3 S_1$ and $^1 P_1$ channels for the first time. The phase shift of the $^3 S_1$ channel, where a large repulsive core was predicted owing to the Pauli effect between quarks, was evaluated as $20^\circ

To elucidate the mechanism of 6-hydroxydopamine (6-OHDA)-induced Zn2+ toxicity, which is involved in neurodegeneration in the substantia nigra pars compacta (SNpc) of rats, we postulated that intracellular hydrogen peroxide (H2O2) produced by 6-OHDA is a trigger for intracellular Zn2+ dysregulation in the SNpc. Intracellular H2O2 level in the SNpc elevated by 6-OHDA was completely inhibited by co-injection of GBR 13069 dihydrochloride (GBR), a dopamine reuptake inhibitor, suggesting that 6-OHDA taken up through dopamine transporters produces H2O2 in the intercellular compartment of dopaminergic neurons. When the SNpc was perfused with H2O2, H2O2 accumulated glutamate in the extracellular compartment and the accumulation was inhibited in the presence of N-(p-amylcinnamoyl)anthranilic acid (ACA), a blocker of the transient receptor potential melastatin 2 (TRPM2) channels. In addition to 6-OHDA, H2O2 also induced intracellular Zn2+ dysregulation via AMPA receptor activation followed by nigral dopaminergic degeneration. Furthermore, 6-OHDA-induced nigral dopaminergic degeneration was completely inhibited by co-injection of HYDROP, an intracellular H2O2 scavenger or GBR into the SNpc. The present study indicates that H2O2 is produced by 6-OHDA taken up through dopamine transporters in the SNpc, is retrogradely transported to presynaptic glutamatergic terminals, activates TRPM2 channels, accumulates glutamate in the extracellular compartment, and induces intracellular Zn2+ dysregulation via AMPA receptor activation, resulting in nigral dopaminergic degeneration. It is likely that intracellular H2O2, but not extracellular H2O2, is a key trigger for nigral dopaminergic degeneration via intracellular Zn2+ dysregulation.

Bound-systems of $��^-$--$^{14}_{}{\rm N}$ are studied via $��^-$ capture at rest followed by emission of a twin single-$��$ hypernucleus in the emulsion detectors. Two events forming extremely deep $��^-$ bound states were obtained by analysis of a hybrid method in the E07 experiment at J-PARC and reanalysis of the E373 experiment at KEK-PS. The decay mode of one event was assigned as $��^-+^{14}_{}{\rm N}\to^{5}_��{\rm He}$+$^{5}_��{\rm He}$+$^{4}_{}{\rm He}$+n. Since there are no excited states for daughter particles, the binding energy of the $��^-$ hyperon, $B_{��^-}$, in $^{14}_{}{\rm N}$ nucleus was uniquely determined to be 6.27 $\pm$ 0.27 MeV. Another $��^-$--$^{14}_{}{\rm N}$ system via the decay $^{9}_��{\rm Be}$ + $^{5}_��{\rm He}$ + n brings a $B_{��^-}$ value, 8.00 $\pm$ 0.77 MeV or 4.96 $\pm$ 0.77 MeV, where the two possible values of $B_{��^-}$ correspond to the ground and the excited states of the daughter $^{9}_��{\rm Be}$ nucleus, respectively. Because the $B_{��^-}$ values are larger than those of the previously reported events (KISO and IBUKI), which are both interpreted as the nuclear $1p$ state of the $��^-$--$^{14}_{}{\rm N}$ system, these new events give the first indication of the nuclear $1s$ state of the $��$ hypernucleus, $^{15}_��{\rm C}$., 26 pages, 7 figures

The differential cross sections of the ��-p --> �� n reaction were measured accurately for the ��- momentum (p_{��}) ranging from 470 to 650 MeV/c at the J-PARC Hadron Experimental Facility. Precise angular information about the ��-p --> �� n reaction was obtained for the first time by detecting approximately 100 reaction events at each angular step of ��cos�� = 0.1. The obtained differential cross sections show slightly forward-peaking structure in the measured momentum regions.The cross sections integrated for -0.7 < cos�� < 1.0 were obtained as 22.5 +- 0.68 (stat.) +- 0.65 (syst.) mb and 15.8 +-0.83(stat.) +- 0.52 (syst.) mb for 470, arXiv admin note: text overlap with arXiv:2104.13608

In an emulsion-counter hybrid experiment performed at J-PARC, a $��^-$ absorption event was observed which decayed into twin single-$��$ hypernuclei. Kinematic calculations enabled a unique identification of the reaction process as $��^{-} + ^{14}$N$\ \rightarrow\ ^{10}_��$Be + $^5_��$He. For the binding energy of the $��^{-}$ hyperon in the $��^-$-$^{14}$N system a value of $1.27 \pm 0.21$ MeV was deduced. The energy level of $��^-$ is likely a nuclear $1p$ state which indicates a weak $��N$-$����$ coupling.

Engineering and Applied Science Research, 46, 1, 64-71

We report on the first observation of $��$ rays emitted from an $sd$-shell hypernucleus, $\rm ^{19}_��F$. The energy spacing between the ground state doublet, $1/2^{+}$ and $3/2^{+}$ states, of $\rm ^{19}_��F$ is determined to be $\rm 315.5 \pm 0.4 (stat) ^{+0.6}_{-0.5} (syst)~keV$ by measuring the $��$-ray energy from the $M1(3/2^{+} \rightarrow 1/2^{+})$ transition. In addition, three $��$-ray peaks were observed and assigned as $E2(5/2^{+} \rightarrow 1/2^{+})$, $E1(1/2^{-} \rightarrow 1/2^{+})$, and $E1(1/2^{-} \rightarrow 3/2^{+})$ transitions. The excitation energies of the $5/2^{+}$ and $1/2^{-}$ states are determined to be $\rm 895.2 \pm 0.3 (stat) \pm 0.5 (syst)~keV$ and $\rm 1265.6 \pm 1.2 (stat) ^{+0.7}_{-0.5} (syst)~keV$, respectively. It is found that the ground state doublet spacing is well described by theoretical models based on existing $s$- and $p$-shell hypernuclear data.

We searched for the bound state of the neutron-rich $��$-hypernucleus ${}^{6}_��$H, using the ${}^{6}$Li($��^{-}, K^{+}$)X double charge-exchange reaction at a $��^{-}$ beam momentum of 1.2 GeV/c at J-PARC. A total of $1.4 \times 10^{12}$ $��^{-}$ was driven onto a ${}^{6}$Li target of 3.5-g/$\rm cm^2$ thickness. No event was observed below the bound threshold, i.e., the mass of ${}^{4}_��$H + 2n, in the missing-mass spectrum of the ${}^{6}$Li($��^{-}, K^{+}$)X reaction in the $2^{\circ}$ < $��_{��K}$ < $20^{\circ}$ angular range. Furthermore, no event was found up to 2.8 MeV/$c^2$ above the bound threshold. We obtained the the double-differential cross section spectra of the ${}^{6}$Li($��^{-}, K^{+}$)X reaction in the angular range of $2^{\circ}$ < $��_{��K}$ < $14^{\circ}$. An upper limit of 0.56 nb/sr (90% C.L.) was obtained for the production cross section of the ${}^{6}_��$H hypernucleus bound state. In addition, not only the bound state region, but also the $��$ continuum region and part of the $��^{-}$ quasi-free production region of the ${}^{6}$Li($��^{-}, K^{+}$)X reaction, were obtained with high statistics. The present missing-mass spectrum will facilitate the investigation of the $��^{-}$-nucleus optical potential for $��^{-}$-${}^{5}$He through spectrum shape analysis., 24 pages, 17 figures

Yacon is a medicinal plant used as a traditional medicine by the natives in South America. In Japan, it becomes popular as a health food. Sesquiterpene Lactones (SLs) from yacon leaves were investigated and the active SLs such as enhydrin, uvedalin and sonchifolin, bearing alpha-methylene-gamma-lactone and epoxides as the active functional groups, were identified by 1H-6000 MHz-NMR. Chemopreventive and cytotoxic activities were determined using different primary screening methods. In this study, all tested SLs strongly inhibited TPA-induced deformed of Raji cells. The IC50 values of yacon SLs from anti-deforming assay were 0.04-0.4 microM. Interestingly, yacon SLs showed more potential of chemo preventive activity than both curcumin and parthenolide. However, the cytotoxicity on Raji cells was observed at high concentration of yacon SLs. The degree of anti-deformation was ranked in order: enhydrin >uvedalin >sonchifolin >parthenolide >curcumin. As according to structure-activity relationship, the high activities of enhydrin, uvedalin and sonchifolin may be due to the 2-methyl-2-butenoate and its epoxide moiety.

Contemporary approaches for vaccination and immunotherapy are often capable of eliciting strong T-cell responses against tumor antigens. However, such responses are not parallel to clinical tumor regression. The development of evasion mechanisms within tumor microenvironment may be responsible for poor therapeutic responses. We report here that constitutive or inducible expression of B7-H1, a B7 family molecule widely expressed by cancers, confers resistance to therapeutic anti-CD137 antibody in mice with established tumors. The resistance is accompanied with failure of antigen-specific CD8+ CTLs to destroy tumor cells without impairment of CTL function. Blockade of B7-H1 or PD-1 by specific monoclonal antibodies could reverse this resistance and profoundly enhance therapeutic efficacy. Our findings support that B7-H1/PD-1 forms a molecular shield to prevent destruction by CTLs and implicate new approaches for immunotherapy of human cancers.

Level structure of the $^{12}_��$C hypernucleus was precisely determined by means of $��$-ray spectroscopy. We identified four $��$-ray transitions via the $^{12}$C$(��^{+},K^{+}��)$ reaction using a germanium detector array, Hyperball2. The spacing of the ground-state doublet $(2^{-}_{1},1^{-}_{1})$ was measured to be $161.5\pm0.3\text{(stat)}\pm0.3\text{(syst)}$\,keV from the direct $M1$ transition. Excitation energies of the $1^{-}_{2}$ and $1^{-}_{3}$ states were measured to be $2832\pm3\pm4$\,keV and $6050\pm8\pm7$\,keV, respectively. The obtained level energies provide definitive references for the reaction spectroscopy of $��$ hypernuclei.

The energy spacing between the ground-state spin doublet of $^4_��$He(1$^+$,0$^+$) was determined to be $1406 \pm 2 \pm 2$ keV, by measuring $��$ rays for the $1^+ \to 0^+$ transition with a high efficiency germanium detector array in coincidence with the $^4$He$(K^-,��^-)$ $^4_��$He reaction at J-PARC. In comparison to the corresponding energy spacing in the mirror hypernucleus $^4_��$H, the present result clearly indicates the existence of charge symmetry breaking (CSB) in $��N$ interaction. It is also found that the CSB effect is large in the $0^+$ ground state but is by one order of magnitude smaller in the $1^+$ excited state, demonstrating that the $��N$ CSB interaction has spin dependence.

The pentaquark $��^+$ has been searched for via the $��^-p \to K^-X$ reaction with beam momenta of 1.92 and 2.01 GeV/$c$ at J-PARC. A missing mass resolution of 2 MeV (FWHM) was achieved but no sharp peak structure was observed. The upper limits on the production cross section averaged over the scattering angle from 2$^{\circ}$ to 15$^{\circ}$ in the laboratory frame were found to be less than 0.28 $��$b/sr at the 90\% confidence level for both the 1.92- and 2.01-GeV/$c$ data. The systematic uncertainty of the upper limits was controlled within 10\%. Constraints on the $��^+$ decay width were also evaluated with a theoretical calculation using effective Lagrangian. The present result implies that the width should be less than 0.36 and 1.9 MeV for the spin-parity of $1/2^+$ and $1/2^-$, respectively., 12 pages, 9 figures; published version

A study of the $^2$H$(��,��)$X reaction was performed using a tagged photon beam at the Research Center for Electron Photon Science (ELPH), Tohoku University. The photoproduced $��$ was measured in the $p{��^{-}}$ decay channel by the upgraded Neutral Kaon Spectrometer (NKS2+). The momentum integrated differential cross section was determined as a function of the scatting angle of $��$ in the laboratory frame for five energy bins. Our results indicated a peak in the cross section at angles smaller than cos$��^{LAB}_��$ = $0.96$. The experimentally obtained angular distributions were compared to isobar models, Kaon-Maid (KM) and Saclay-Lyon A (SLA), in addition to the composite Regge-plus-resonance (RPR) model. Both SLA(r$K_{1}K_��$ = $-1.4$) and RPR describe the data quite well in contrast to the KM model, which substantially under predicted the cross section at the most forward angles. With the anticipated finalized data on $��$ integrated and momentum dependent differential cross sections of $^2$H$(��,��)$X~\cite{Kaneta_Beckford}, we present our findings on the angular distributions in this report.

We have carried out an experiment to search for a neutron-rich hypernucleus, $^6_��$H, by the $^6$Li($��^-,K^+$) reaction at $p_{��^-}$ =1.2 GeV/$c$. The obtained missing mass spectrum with an estimated energy resolution of 3.2 MeV (FWHM) showed no peak structure corresponding to the $^6_��$H hypernucleus neither below nor above the $^4_��$H$+2n$ particle decay threshold. An upper limit of the production cross section for the bound $^6_��$H hypernucleus was estimated to be 1.2 nb/sr at 90% confidence level., 6 pages, 5 figures, published version

The $��^+$ pentaquark baryon was searched for via the $��^-p\to K^-X$ reaction in a missing-mass resolution of 1.4 MeV/$c^2$(FWHM) at J-PARC. $��^-$ meson beams were incident on the liquid hydrogen target with the beam momentum of 1.92 GeV/$c$. No peak structure corresponding to the $��^+$ mass was observed. The upper limit of the production cross section averaged over the scattering angle of 2$^{\circ}$ to 15$^{\circ}$ in the laboratory frame was obtained to be 0.26 $��$b/sr in the mass region of 1.51$-$1.55 GeV/$c^2$.The upper limit of the $��^+$ decay width using the effective Lagrangian approach was obtained to be 0.72 MeV/$c^2$ and 3.1 MeV/$c^2$ for $J^P_��=1/2^+$ and $J^P_��=1/2^-$, respectively., 5 pages, 3 figures, 1 table

An experiment was carried out with the NKS2+ in 2010 at the Research Center for Electron Photon Science (ELPH), in which tagged photon beams in the range of 0.8 $\le$ $E_��$ $\le$ 1.1 GeV were impinged on a liquid $^2$H target positioned at the center of the NKS2+. The produced $��$ was subsequently detected by the $p{��^{-}}$ decay channel. Integrated cross sections of the $^2$H$(��,��)$X in the angular region of 0.9 $\le$ $\cos��_��^{LAB}$ $\le$ 1.0 was derived and compared with preceding experimental results of the NKS2 collaboration. In addition, the momentum spectra for two photon energy regions were also procured. The $��$ angle dependent cross sections as a function of the scattering angle in the laboratory system was additionally deduced. We present the latest results on the excitation function of $��$ photoproduction, the momentum distributions, angular distributions, and polarization., 6 pages, 6 pages. Proceedings of the International Workshop on Strangeness Nuclear Physics (SNP12), August 27 - 29, 2012, Neyagawa, Osaka, Japan

An experiment designed to investigate the strangeness photoproduction process using a tagged photon beam in the energy range of 0.90 -1.08 GeV incident on a liquid deuterium target was successfully performed. The purpose of the experiment was to measure the production of neutral kaons and the lambda particles on a deuteron. The generation of photo produced particles was verified by the measurement of their decayed charged particles in the Neutral Kaon Spectrometer 2. The reconstructed invariant mass distributions were achieved by selecting events where two or more particles tracks were identified. Preliminary results are presented here., Comment: Originally submitted to the Research Center for Electron Photon Science (ELPH) Annual Report, Tohoku University Vol. 2 (2011) (ELPH Experiment : #2633, #2638, #2658)

We explored the clustering properties of Lyman break galaxies at z = 4 and 5 with an angular two-point correlation function on the basis of the very deep and wide Subaru Deep Field data. We confirmed the previous result that the clustering strength of LBGs depends on the UV luminosity in the sense that brighter LBGs are more strongly clustered. In addition, we found an apparent dependence of the correlation function slope on UV luminosity for LBGs at both z = 4 and 5. More luminous LBGs have a steeper correlation function. The bias parameter was found to be a scale-dependent function for bright LBGs, whereas it appears to be almost scale-independent for faint LBGs. Luminous LBGs have a higher bias at smaller angular scales, which decreases as the scale increases. To compare these observational results, we constructed numerical mock LBG catalogs based on a semianalytic model of hierarchical clustering combined with high-resolution N-body simulation, carefully mimicking the observational selection effects. The luminosity functions and the overall correlation functions for LBGs at z = 4 and 5 predicted by this mock catalog were found to be almost consistent with the observation. The observed dependence of the clustering on UV luminosity was not reproduced by the model, unless subsamples of distinct halo mass were considered. That is, LBGs belonging to more massive dark halos had steeper and larger amplitude correlation functions. With this model, we found that LBG multiplicity in massive dark halos amplifies the clustering strength at small scales, which steepens the correlation function. The hierarchical clustering model could therefore be reconciled with the observed luminosity dependence of the correlation function if there is a tight correlation between UV luminosity and halo mass. Our finding that the slope of the correlation function depends on luminosity could be an indication that massive dark halos hosted multiple bright LBGs. © 2006. The American Astronomical Society. All rights reserved.

The forward inclusive pion double charge exchange reaction, ^{16}O(pi^-,pi^+)X, at T_0 = 0.50 and 0.75 GeV has been studied in the kinematical region where an additional pion production is forbidden by energy-momentum conservation. The experiment was performed with the SKS spectrometer at KEK PS. The measured ratio of double charge exchange cross-section for these energies dsigma(0.50 GeV)/dOmega / dsigma(0.75 GeV)/dOmega = 1.7 +/- 0.2, disagrees with the value of 7.2 predicted within the conventional sequential single charge exchange mechanism. Possible reasons for the disagreement are discussed in connection with the Glauber inelastic rescatterings., Comment: 4 pages, 5 figures

The asymmetry parameter alpha_p^NM for a proton exclusively emitted in the Lambda p -> np process was, for the first time, measured in the non-mesonic weak decay of a polarized 5_La,bda_He hypernucleus by selecting the proton-neutron pairs emitted in the back-to-back kinematics. The highly polarized 5_Lambda_He was abundantly produced with the (pi+,K+) reaction at 1.05GeV/c in the scattering angular range of +-15$ degrees. The obtained value alpha_p^NM=0.31+-0.22, as well as that for inclusive protons, alpha_p^NM=0.11+-0.08+-0.04, largely contradicts recent theoretical values of around -0.6, although these calculations well reproduce the branching ratios of non-mesonic weak decay., 4pages, 2 figures, submitted to Physical Review Letters

We performed a coincidence measurement of two nucleons emitted from the nonmesonic weak decay (NMWD) of ^{5}_��He formed via the ^{6}Li(��^+,K^+) reaction. The energies of two nucleons and the pair number distributions in the opening angle between them were measured. In both np and nn pairs, we observed a clean back-to-back correlation coming from the two-body decay of ��p --> n p and ��n --> n n, respectively. The ratio of the nucleon pair numbers was N_{nn}/N_{np}=0.45 \pm 0.11(stat)\pm 0.03(syst) in the kinematic region of cos(theta_{NN}) < -0.8. Since each decay mode was exclusively detected, the measured ratio should be close to the ratio of ��(��p --> np)/��(��n --> nn). The ratio is consistent with recent theoretical calculations based on the heavy meson/direct quark exchange picture., Submitted to Phys. Rev. lett., 4 pages, 3 figures

We reported in a previous paper the discovery of large-scale structure of Lyman Alpha emitters (LAEs) at z=4.86+-0.03 with a projected size of 20 Mpc x 50 Mpc in narrow-band data of a 25' x 45' area of the Subaru Deep Field (Omega_0=0.3, lambda_0=0.7, H0=70 km/s/Mpc). However, the surveyed area, which corresponds to 55 Mpc x 100 Mpc, was not large enough that we can conclude that we are seeing a typical distribution of z~5 LAEs. In this Letter, we report the results of follow-up imaging of the same sky area using a new narrow-band filter (NB704, lambda_c=7046 A and FWHM=100 A) to detect LAEs at z=4.79, i.e., LAEs lying closer to us by 39 Mpc on average than the z=4.86 objects. We detect 51 LAEs at z=4.79+-0.04 down to NB704=25.7, and find that their sky distribution is quite different from the z=4.86 LAEs'. The clustering of z=4.79 LAEs is very weak on any scales and there is no large-scale high- contrast structure. The shape and the amplitude of the angular correlation function are thus largely different between the two samples. These results demonstrate a large cosmic variance in the clustering properties of LAEs on scales of ~ 50 Mpc., Comment: 4 pages (uses emulateapj5.sty), accepted for ApJL

We have measured both yields of neutron-proton and neutron-neutron pairs emitted from the non-mesonic weak decay process of 5_Lambda-He and 12_Lambda-C hypernuclei produced via the (pi^+,K^+) reaction for the first time. We observed clean back-to-back correlation of the np- and nn-pairs in the coincidence spectra for both hypernuclei. The ratio of those back-to-back pair yields, Nnn / Nnp, must be close to the ratio of neutron- and proton-induced decay widths of the decay, Gn(Lambda n -> nn)/Gp(Lambda p -> np). The obtained ratios for each hypernuclei support recent calculations based on short-range interactions., 4 pages, 1 figure, International Nuclear Physics Conference (INPC 2004), Goteborg, Sweden, June 27 - July 2, 2004, to appear in Nuclear Physics A

We have precisely measured $��\to p��^-$ decay width of \5LHe and demonstrated significantly larger $��$ -$��$ overlap than expected from the central repulsion $��$-$��$ potential, which is derived from YNG ��$-nucleon interaction., 4 pages, 3 figures

We precisely measured pi^0 branching ratios of 5_Lambda-He and 12_Lambda-C hypernuclei produced via (pi^+,k^+) reaction. Using these pi^0 branching ratios with the pi^- branching ratios and the lifetimes, we obtained the pi^0 decay widths and the non-mesonic weak decay widths at high statistics with the accuracy of ~5 % (stat) for both hypernuclei., Comment: 4pages, 4figures, International Conference on Hypernuclear and Strange Particle Physics (HYP2003)

In pharmacokinetic studies, a variety of analytical method including radioisotopic detection and HPLC (high performance liquid chromatography) has been used. In the present investigation, we developed in vivo BCM (Blood Circulation Monitoring)-ESR method, which is a new technique with a conventional X-band ESR spectrometer for observing stable free radicals in the circulating blood of living rats under anaesthesia. Both 5-(PROXYL derivatives) and 6-(TEMPO d derivatives) membered nitroxide spin probes with various types of substituent functional group were used. After physico-chemical properties of the spin probes such as hyperfine coupling constant (A-value), g-value and partition coefficient as well as chemical stability of the compounds in the fresh blood were obtained, the in vivo BCM-ESR method was performed in normal rats. Several pharmacokinetic parameters such as half-life of the probes, distribution volume, total body clearance and mean residence time were obtained and discussed in terms of their chemical structures. In addition, clearance of a spin probe was related to the urine concentration. The BCM-ESR method was found to be very useful to observe free radicals at the real time. By time-dependent ESR signal decay of spin probes, pharmacokinetic parameters were obtained.

Recently ultraviolet light (UV) reaching the Earth's surface has been gradually increasing in amounts by the destruction of the ozone layers. Large parts of UV are absorbed in the cornea and lens, and only a few amounts reach the retina; however, the effect on the retina is not fully elucidated. 38 rats were irradiated 0.5- 5.0 ~ / c mUV~ f rom 6 to 50 times every 24 hours, and their retinal effects were investigated morphologicaily, immunohistochemically and immunochemically for superoxide dismutases (SOD). Morphologically, the destruction of rod outer segments (ROS) and dissociation of cell membranes between the pigment epithelial cells (PE) were already observed by 6 times 0.5 ~ / c mUV~ i rradiations. As the doses of UV increased, heterochromatins and lipid droplets increased in the PE. Significant damage was not observed, except in ROS and PE. In normal retina, CuIZn SOD were mainly distributed from the inner limiting membrane (ILM) to the ganglion cell layer, and the PE; however, after 6 times 0.5 ~ / c mUV~ i rradiations, the distribution became widened from inner to outer plexiform layer (OPL). At that time, the concentrations of CuKn and Mn SOD increased in the retina. The present study reveals that the morphological damage caused by UV irradiation is observed in the ROS and PE, where no immunoreactivities could be detected to CuIZn and Mn SOD. However, morphological damage was not from the ILM to OPL, where the imrnunoreactivities to both Cu/Zn and Mn SOD were observed.

The distribution of intestinal metaplasia in relation to the acid-secreting are was investigated in 66 patients not suffering from gastroduodenal diseases. Studies were made via the endoscopic Congo Red test in combination with the methylene blue staining method. In this test, the acid-secreting area is identified as a "discolored" area in which Congo Red turns from red to blue-black, and areas of intestinal metaplasia were observed as areas staining blue with methylen blue. A close relationship was found between the acid-secreting area and the distribution of intestinal metaplasia; in general, intestinal metaplasia tended to be more extensive and more frequent when the acid-secreting area was small. It was also found that intestinal metaplasia increased with age. However, even in patients who were over 40 years of age, intestinal metaplasia was seen in 12.5% only, if the acid-secreting area was large. Hence, it appears likely that development of intestinal metaplasia is more closely related to the acid-secreting function than to aging.

The relation of the gastric acid-secreting area to the healing and recurrence of duodenal ulcers was examined in 67 patients with duodenal ulcers. Studies were made by the endoscopic Congo red test developed at this institute. Results indicate a close correlation between the healing and recurrence of duodenal ulcers, and the extent of the acid-secreting area. In general, when the acid-secreting area was large, the ulcers did not heal satisfactorily within 4 weeks after initiation of medical treatment and frequently recurred. In contrast, when the acid-secreting area was small, the ulcers tended to heal rapidly and not to recur.

About 120 million people worldwide suffer from congenital (early-onset) hearing loss. Thirty percent of them have syndromic hearing loss and the remaining 70% have non-syndromic hearing loss. In addition, a large number of elderly people worldwide suffer from age-related (late-onset) hearing loss. c-Ret and c-RET have been shown to be essential for the development and maintenance of neurons including the enteric nervous system (ENS) in mice and humans. Impairments of endothelin receptor B (EDNRB) and SOX10 have been shown to cause a significantly increased risk of dominant sensorineural deafness in Hirschsprung disease (HSCR) patients. We have recently shown that impairments of tyrosine 1062 (Y1062) phosphorylation in c-Ret causes syndromic congenital deafness in mice and humans and non-syndromic age-related hearing loss with neurodegeneration of spiral ganglion neurons (SGNs) in mice. This review focuses on the pathogenesis of hearing loss caused by impairments of c-Ret.