Performance of the TPC with Micro Pixel Chamber Readout: micro-TPC

Micro-TPC, a time projection chamber(TPC) with micro pixel chamber($\mu$-PIC) readout was developed for the detection of the three-dimensional fine(sub-m illimeter) tracks of charged particles. We developed a two-dimensional position sensitive gaseous detector, or the $\mu$-PIC, with the detection area of 10$\times$10 cm${}^{2}$ and 65536 anode electrodes of 400 $\mu$m pitch. We achieved the gas gain of over 10000 without any other multipliers. With the pipe-line readout system specially developed for the $\mu$-PIC, we detected X-rays at the rate as high as 7.7 Mcps. We attached a drift cage with an 8 cm drift length to the $\mu$-PIC and developed a micro-TPC. We measured the basic performances of the micro-TPC and took three-dimensional tracks of electrons. We also developed a prototype of the MeV gamma-ray imaging detector which is a hybrid of the micro-TPC and NaI(Tl) scintillators and confirmed its concept by reconstructing the obtained data.Comment: 6 pages 16 figures, submitted for IEEE/TNS 200

Bioinspired One-Step Synthesis of Pomegranate-like Silica@Gold Nanoparticles with Surface-Enhanced Raman Scattering Activity

Gold–silica (Au–SiO2) nanohybrids are of great technological importance, and it is crucial to develop facile synthetic protocols to prepare Au–SiO2 nanohybrids with novel structures. Here we report the bioinspired synthesis of pomegranate-like SiO2@Au nanoparticles (P-SiO2@Au NPs) via one-step aqueous synthesis from chloroauric acid and tetraethyl orthosilicate mediated by a basic amino acid, arginine. Effects of chloroauric acid, tetraethyl orthosilicate, and arginine on the morphology and optical property of the products are investigated in detail. The P-SiO2@Au NPs achieve tunable plasmon resonance depending on the amount of chloroauric acid, which affects the size and shape of the P-SiO2@Au NPs. Finite-difference time-domain simulations are performed, revealing that the plasmon peak red-shifts with increasing particle size. Arginine serves as the reducing and capping agents for Au as well as the catalyst for SiO2 formation and also promotes the combination of Au and SiO2. Formation process of the P-SiO2@Au NPs is clarified through time-course analysis. The P-SiO2@Au NPs show good sensitivity for both colloidal and paper-based surface-enhanced Raman scattering measurements. They achieve enhancement factors of 4.3 × 107–8.5 × 107 and a mass detection limit of ca. 1 ng using thiophenol as the model analyte.The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.langmuir.0c00334

Performance of a micro-TPC for a time-resolved neutron PSD

We report on the performance of a micro-TPC with a micro pixel chamber($\mu$-PIC) readout for a time-resolved neutron position-sensitive detector(PSD). Three-dimensional tracks and the Bragg curves of protons with energies of around 1 MeV were clearly detected by the micro-TPC. More than 95% of gamma-rays of 511 keV were found to be discriminated by simple analysis. Simulation studies showed that the total track length of proton and triton emitted from the $\rm {}^{3}He$(n,p(573 keV))$\rm {}^{3}H(191 keV)$ reaction is about 1.2 cm, and that both particles have large energy losses ($\rm > 200 keV/cm$) in 1 atm Ar+$\rm C_{2}H_{6}(10$+${}^{3}$He($< 1$). These values suit the current performance of the micro-TPC, and we conclude that a time-resolved neutron PSD with spatial resolution of sub-millimeters shall be developed as an application of the micro-TPC.Comment: 13 pages, 10 figures, to appear in NIM

Transfer of rice mitochondrial ribosomal protein L6 gene to the nucleus: acquisition of the 5'-untranslated region via a transposable element

<p>Abstract</p> <p>Background</p> <p>The mitochondria of contemporary organisms contain fewer genes than the ancestral bacteria are predicted to have contained. Because most of the mitochondrial proteins are encoded in the nucleus, the genes would have been transferred from the mitochondrion to the nucleus at some stage of evolution and they must have acquired cis-regulatory elements compatible with eukaryotic gene expression. However, most of such processes remain unknown.</p> <p>Results</p> <p>The ribosomal protein L6 gene (<it>rpl6</it>) has been lost in presently-known angiosperm mitochondrial genomes. We found that each of the two rice <it>rpl6 </it>genes (<it>OsRpl6-1 </it>and <it>OsRpl6-2</it>) has an intron in an identical position within the 5'-untranslated region (UTR), which suggests a duplication of the <it>rpl6 </it>gene after its transfer to the nucleus. Each of the predicted RPL6 proteins lacks an N-terminal extension as a mitochondrial targeting signal. Transient assays using green fluorescent protein indicated that their mature N-terminal coding regions contain the mitochondrial targeting information. Reverse transcription-PCR analysis showed that <it>OsRpl6-2 </it>expresses considerably fewer transcripts than <it>OsRpl6-1</it>. This might be the result of differences in promoter regions because the 5'-noncoding regions of the two <it>rpl6 </it>genes differ at a point close to the center of the intron. There are several sequences homologous to the region around the 5'-UTR of <it>OsRpl6-1 </it>in the rice genome. These sequences have characteristics similar to those of the transposable elements (TE) belonging to the <it>PIF</it>/Harbinger superfamily.</p> <p>Conclusion</p> <p>The above evidences suggest a novel mechanism in which the 5'-UTR of the transferred mitochondrial gene was acquired via a TE. Since the 5'-UTRs and introns within the 5'-UTRs often contain transcriptional and posttranscriptional cis-elements, the transferred rice mitochondrial <it>rpl6 </it>gene may have acquired its cis-element from a TE.</p

Precipitation monitoring using multi-instrument ovservation system at various spatiotemporal scales

金沢大学大学院自然科学研究科2005 International Symposium on Environmental Mornitoring in East Asia -Remote Sensing and Forests-,Hosted The EMEA Project, Kanazawa University 21st=Century COE Program -Environmental Monitoring and Predicition of Long- and Short- Term Dynamics of Pan-Japan Sea Area- ,予稿集, EMEA 2005 in Kanazawa, 国際学術研究公開シンポジウム『東アジアの環境モニタリング』－リモートセンシングと森林－,年月日：200511月28日～29日, 場所：KKRホテル金沢, 金沢大学自然科学研究科, 主催：金沢大学EMEAプロジェクト, 共催：金沢大学21世紀COEプログラム「環日本海域の環境変動と長期・短期変動予測

6.EMEA International Symposium in Kanazawa, Japan

金沢大学大学院自然科学研究科Project Number 14404021, Peport of Research Project ; Grant-in-Aid for Scientific Research(B)(2), from April 2002 to March 2006, Edited by Muramoto,Ken-ichiroKamata, NaotoKawanishi, TakuyaKubo, MamoruLiu, JiyuanLee, Kyu-Sung , 人工衛星データ活用のための東アジアの植生調査、課題番号14404021, 平成14年度～平成17年度科学研究費補助金, 基盤研究（B)(2)研究成果報告書, 研究代表者：村本, 健一郎, 金沢大学自然科学研究科教

Assembly of Massive Galaxies in a High-z Protocluster

We present the results of wide-field deep JHK imaging of the SSA22 field using MOIRCS instrument equipped with Subaru telescope. The observed field is 112 arcmin^2 in area, which covers the z=3.1 protocluster characterized by the overdensities of Ly Alpha emitters (LAEs) and Ly Alpha Blobs (LABs). The 5 sigma limiting magnitude is K_{AB} = 24.3. We extract the potential protocluster members from the K-selected sample by using the multi-band photometric-redshift selection as well as the simple color cut for distant red galaxies (DRGs; J-K_{AB}>1.4). The surface number density of DRGs in our observed fields shows clear excess compared with those in the blank fields, and the location of the densest area whose projected overdensity is twice the average coincides with the large-scale density peak of LAEs. We also found that K-band counterparts with z_{phot} = 3.1 are detected for 75% (15/20) of the LABs within their Ly Alpha halo, and the 40 % (8/20) of LABs have multiple components, which gives a direct evidence of the hierarchical multiple merging in galaxy formation. The stellar mass ofLABs correlates with their luminosity, isophotal area, and the Ly Alpha velocity widths, implying that the physical scale and the dynamical motion of Ly Alpha emission are closely related to their previous star-formation activities. Highly dust-obscured galaxies such as hyper extremely red objects (HEROs; J-K_{AB}>2.1) and plausible K-band counterparts of submillimeter sources are also populated in the high density region.Comment: 21pages, accepted for publication in Astrophysical Journa