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101.
S Minato 《Radioisotopes》1990,39(4):170-173
This note describes a method of direct measurement of airborne gamma-rays primarily from 222Rn daughters using a NaI(Tl) scintillation spectrometer with lead shields. This method has the advantage of being able to maintain the system easily compared to other usual systems including a pump. The pulse-height distributions are successively fed to a floppy disk in a personal computer every unit time. The gain shifts can be corrected automatically by a computer program. This technique would be applicable to the estimation of 222Rn daughters concentration and to examination of disequilibrium between 214Pb(RaB) and 214Bi(RaC) and of those height distribution up to about 200 m. The accuracy for estimating the concentration is as good as that of the filter method. 相似文献
102.
103.
Yoshihisa Miyamoto Hideki Miyaji Kenjiro Asai 《Journal of Polymer Science.Polymer Physics》1980,18(3):597-606
The anisotropy of the crystalline relaxation (α relaxation) in oriented poly(vinylidene fluoride) in crystal form II has been studied. The dielectric increment Δε is analyzed on the basis of the two-site model. A linear relation between Δε/χξ and cos2θ is obtained, where χ is the degree of crystallinity, ξ is the ratio of the internal field to the applied field, and θ is the angle between the applied electric field and the molecular axis. The dipole moment changes direction only along the molecular axis in the relaxation in crystal form II; the molecular motion cannot be explained by chain rotation around the molecular axis. Possible models for the α relaxation are proposed: change in conformation with internal rotation can occur in the crystalline chains, and defects in the crystalline regions play an important role in the α relaxation. 相似文献
104.
Summary The coagulation of ferric oxide sol by several organic solvents, such as ethyl alcohol, has been studied. It has been observed
that the coagulation takes place when the dielectric constant of medium is lowered to a certain critical value for coagulation
by the addition of any organic solvent. The lowering of dielectric constant of medium is accompanied by the contraction of
electrical double layer around sol particle, which leads to coagulation.
With 1 figure and I table 相似文献
Zusammenfassung Koagulation eines Ferrioxidsols durch verschiedene organische L?sungsmittel findet statt, wenn die Dielektrizit?tskonstante bis auf einen „kritischen” Wert durch Zufügung irgendeines organischen L?sungsmittels vermindert wird. Die Erniedrigung der DK des Mediums bedingt die Kontraktion der elektrischen Doppelschichten der Solpartikel, so da? Koagulation erfolgt.
With 1 figure and I table 相似文献
105.
106.
107.
Tomoki Saka Toru Okaki Shohei Ifuku Yukiko Yamashita Kasumi Sato Shota Miyawaki Akiko Kamori Atsushi Kato Isao Adachi Yasuhiro Tezuka Peter G. Kiria Osamu Onomura Daishiro Minato Kenji Sugimoto Yuji Matsuya Naoki Toyooka 《Tetrahedron》2013
Synthesis and inhibitory activities against α-l-fucosidase of phenylalkyl-substituted polyhydroxypiperidines have been described. Among the newly synthesized compounds, 2,4,6-trichloro derivative (16q) showed very high inhibitory activity against α-l-fucosidase with IC50 value of 0.005 μM, and Ki values of 0.0011 μM, respectively. 相似文献
108.
Kawaguchi M Okabe T Okudaira S Hanaoka K Fujikawa Y Terai T Komatsu T Kojima H Aoki J Nagano T 《Journal of the American Chemical Society》2011,133(31):12021-12030
Nucleotide pyrophosphatases/phosphodiesterases (NPPs) are ubiquitous membrane-associated or secreted ectoenzymes that have a role in regulating extracellular nucleotide and phospholipid metabolism. Among the members of the NPP family, NPP1 and -3 act on nucleotides such as ATP, while NPP2, -6, and -7 act on phospholipids such as lysophosphatidylcholine and sphingomyelin. NPP6, a recently characterized NPP family member, is a choline-specific glycerophosphodiester phosphodiesterase, but its functions remain to be analyzed, partly due to the lack of highly sensitive activity assay systems and practical inhibitors. Here we report synthesis of novel NPP6 fluorescence probes, TG-mPC and its analogues TG-mPC(3)C, TG-mPC(5)C, TG-mPENE, TG-mPEA, TG-mPhos, TG-mPA, TG-mPMe, and TG-mPPr. Among the seven NPPs, only NPP6 hydrolyzed TG-mPC, TG-mPC(3)C, and TG-mPENE. TG-mPC was hydrolyzed in the cell lysate from NPP6-transfected cells, but not control cells, showing that it is suitable for use in cell-based NPP6 assays. We also examined the usefulness of TG-mPC as a fluorescence imaging probe. We further applied TG-mPC to carry out high-throughput NPP6 inhibitor screening and found several NPP6-selective inhibitors in a library of about 80,000 compounds. Through structure-activity relationship (SAR) analysis, we identified a potent and selective NPP6 inhibitor with an IC(50) value of 0.21 μM. Our NPP6-selective fluorescence probe, TG-mPC, and the inhibitor are expected to be useful to elucidate the biological function of NPP6. 相似文献
109.
Sasakura K Hanaoka K Shibuya N Mikami Y Kimura Y Komatsu T Ueno T Terai T Kimura H Nagano T 《Journal of the American Chemical Society》2011,133(45):18003-18005
Hydrogen sulfide (H(2)S) has recently been identified as a biological response modifier. Here, we report the design and synthesis of a novel fluorescence probe for H(2)S, HSip-1, utilizing azamacrocyclic copper(II) ion complex chemistry to control the fluorescence. HSip-1 showed high selectivity and high sensitivity for H(2)S, and its potential for biological applications was confirmed by employing it for fluorescence imaging of H(2)S in live cells. 相似文献
110.
Selective Ablation of β‐Galactosidase‐Expressing Cells with a Rationally Designed Activatable Photosensitizer
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Dr. Yuki Ichikawa Dr. Mako Kamiya Dr. Fumiaki Obata Prof. Masayuki Miura Dr. Takuya Terai Dr. Toru Komatsu Dr. Tasuku Ueno Dr. Kenjiro Hanaoka Prof. Tetsuo Nagano Prof. Yasuteru Urano 《Angewandte Chemie (International ed. in English)》2014,53(26):6772-6775
We have developed an activatable photosensitizer capable of specifically inducing the death of β‐galactosidase‐expressing cells in response to photoirradiation. By using a selenium‐substituted rhodol scaffold bearing β‐galactoside as a targeting substituent, we designed and synthesized HMDESeR‐βGal, which has a non‐phototoxic spirocyclic structure owing to the presence of the galactoside moiety. However, β‐galactosidase efficiently converted HMDESeR‐βGal into phototoxic HMDESeR, which exists predominantly in the open xanthene form. This structural change resulted in drastic recovery of visible‐wavelength absorption and the ability to generate singlet oxygen (1O2). When HMDESeR‐βGal was applied to larval Drosophila melanogaster wing disks, which express β‐galactosidase only in the posterior region, photoirradiation induced cell death in the β‐galactosidase‐expressing region with high specificity. 相似文献