Stress response gene ATF3 is one of the p53 target genes and has a tumor suppressor role in cancer. However, the biological role of p53-ATF3 pathway is not well understood. Death receptor 5 (DR5) is ...a death domain-containing transmembrane receptor that triggers cell death upon binding to its ligand TRAIL (tumor necrosis factor-related apoptosis-inducing ligand), and a combination of TRAIL and agents that increase the expression of DR5 is expected as a novel anticancer therapy. In this report, we demonstrate that ATF3 is required for efficient DR5 induction upon DNA damage by camptothecin (CPT) in colorectal cancer cells. In the absence of ATF3, induction of DR5 messenger RNA and protein is remarkably abrogated, and this is associated with reduced cell death by TRAIL and CPT. By contrast, exogenous expression of ATF3 causes more rapid and elevated expression of DR5, resulting in enhanced sensitivity to apoptotic cell death by TRAIL/CPT. Reporter assay and DNA affinity precipitation assay demonstrate that at least three ATF/CRE motifs at the proximal promoter of the human DR5 gene are involved in the activation of DNA damage-induced DR5 gene transcription. Furthermore, ATF3 is shown to interact with p53 to form a complex on the DR5 gene by Re-chromatin immunoprecipitation assay. Taken together, our results provide a novel insight into the role of ATF3 as an essential co-transcription factor for p53 upon DNA damage, and this may represent a useful biomarker for TRAIL-based anticancer therapy.
A new time projection chamber (TPC) was developed for neutron lifetime measurement using a pulsed cold neutron spallation source at the Japan Proton Accelerator Research Complex (J-PARC). Managing ...considerable background events from natural sources and the beam radioactivity is a challenging aspect of this measurement. To overcome this problem, the developed TPC has unprecedented features such as the use of polyether-ether-ketone plates in the support structure and internal surfaces covered with 6Li-enriched tiles to absorb outlier neutrons. In this paper, the design and performance of the new TPC are reported in detail.
Abstract
In a neutron lifetime measurement at the Japan Proton Accelerator Complex, the neutron lifetime is calculated from the neutron decay rate and the incident neutron flux. The flux is obtained ...by counting the protons emitted from the neutron absorption reaction of ^{3}{\rm He}$ gas, which is diluted in a mixture of working gas in a detector. Hence, it is crucial to determine the amount of ^{3}{\rm He}$ in the mixture. In order to improve the accuracy of the number density of the ^{3}{\rm He}$ nuclei, we have suggested using the ^{14}{\rm N}({\rm n},{\rm p}){}^{14}{\rm C}$ reaction as a reference because this reaction involves similar kinetic energy to the $^3$He(n,p)$^3$H reaction and a smaller reaction cross section to introduce reasonable large partial pressure. The uncertainty of the recommended value of the cross section, however, is not satisfied with our requirement. In this paper we report the most accurate experimental value of the cross section of the $^{14}$N(n,p)$^{14}$C reaction at a neutron velocity of 2200 m s$^{-1}$, measured relative to the $^3$He(n,p)$^3$H reaction. The result was 1.868 $\pm$ 0.003 (stat.) $\pm$ 0.006 (sys.) b. Additionally, the cross section of the $^{17}$O(n,$\alpha$)$^{14}$C reaction at the neutron velocity is also redetermined as 249 $\pm$ 6 mb.
We measured the neutron beam polarization of the BL05/NOP (Neutron Optics and Physics) beamline at J-PARC with an accuracy of less than 10−3 using polarized 3He gas as a neutron spin analyzer. ...Precise polarimetry of the neutron beam is necessary to understand the beamline optics as well as for the asymmetry measurements of the neutron beta decay, which are planned in this beamline.
► We have measured neutron beam polarization with an accuracy of 0.03% using a 3He neutron spin filter. ► This accuracy was achieved by flipping the 3He polarization with adiabatic fast-passage (AFP) NMR. ► The 3He spin flipping canceled most of systematic uncertainties. ► Such accuracy is necessary for the precise neutron beta decay measurements planned at BL05 of the J-PARC spallation neutron source.
We have searched for Θ+ via π−p→K−X reaction using 1.87 and 1.92 GeV/cπ− beam at the K2 beam line of the KEK 12 GeV proton synchrotron. In the missing mass spectrum at beam momentum of 1.92 GeV/c, a ...bump has been found at 1530 MeV/c2 which is consistent with the mass reported by several experiments. The statistical significance of this bump, however, is only 2.5–2.7σ. Therefore we have derived the upper limit of Θ+ production cross section via π−p→K−Θ+ reaction which is 3.9 μb at 90% confidence level assuming that Θ+ is produced isotropically in the center of mass system.
We have measured the optical thickness of a phase object for the first time using multilayer cold neutron interferometer. The measured phase shift of 15.1 ± 1.9 wavelength agreed with the expected ...value of 17.4 ± 0.7 wavelength due to an about 600-μm-thick silicon plate. This demonstration reconfirmed that two paths in our new interferometer were completely separate, and showed its applicability into various precise measurements.
The basic concept of polarisation analysers with bender type supermirrors on the polarised neutron spectrometer, POLANO, which is now under construction in J-PARC/MLF, is described.
Probing ΛΛ Potential C. J. Yoon(Research Center for Nuclear Physics; H. Akikawa; K. Aoki ...
Journal of the Korean Physical Society,
08/2011
Journal Article
Recenzirano
We determined scattering length and effective range of ΛΛ scattering for the ΛΛ relative energy (M_(ΛΛ)-2M_Λ) from ΛΛ threshold to 30 MeV/c_2. Phase shift of the ΛΛ wave function which described by ...scattering length and effective range was determined by fitting the ΛΛ mass spectrum. The obtained scattering length -0.10^(+0.37)_(-1.56) ± 0.04, and effective range 13.90 ^(+14.35)_(-9.13) ± 10.53 fm is the most consistent with the values predicted by using a series of the Nijmegen soft core models NSC97's. However the predicted values by using the Nijmegen hard core model ND (G-matrix), the extended soft core model ESC00, and the Kyoto-Niigata FSS are out of three standard deviations from the determined scattering parameters. Further, we determine ΛΛ potential by fitting the ΛΛ invariant mass spectrum using numerically solved ΛΛ wave function with two-Gaussian shaped potential well. The ΛΛ scattering parameters derived from the wave function are found to be scattering length -0.09, and effective range 29.34 fm with a maximum phase shift of 2.4 deg. KCI Citation Count: 0
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