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71.
Dr. Kenta Arai Takahiko Matsunaga Haruhito Ueno Nozomi Akahoshi Yuumi Sato Dr. Gaurango Chakrabarty Prof. Dr. Govindasamy Mugesh Prof. Dr. Michio Iwaoka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(55):12751-12760
At the redox-active center of thioredoxin reductase (TrxR), a selenenyl sulfide (Se−S) bond is formed between Cys497 and Sec498, which is activated into the thiolselenolate state ([SH,Se−]) by reacting with a nearby dithiol motif ([SHCys59,SHCys64]) present in the other subunit. This process is achieved through two reversible steps: an attack of a cysteinyl thiol of Cys59 at the Se atom of the Se−S bond and a subsequent attack of a remaining thiol at the S atom of the generated mixed Se−S intermediate. However, it is not clear how the kinetically unfavorable second step progresses smoothly in the catalytic cycle. A model study that used synthetic selenenyl sulfides, which mimic the active site structure of human TrxR comprising Cys497, Sec498, and His472, suggested that His472 can play a key role by forming a hydrogen bond with the Se atom of the mixed Se−S intermediate to facilitate the second step. In addition, the selenenyl sulfides exhibited a defensive ability against H2O2-induced oxidative stress in cultured cells, which suggests the possibility for medicinal applications to control the redox balance in cells. 相似文献
72.
Watanabe Sou Senzaki Tatsuya Shibata Atsuhiro Nomura Kazunori Takeuchi Masayuki Nakatani Kiyoharu Matsuura Haruaki Horiuchi Yusuke Arai Tsuyoshi 《Journal of Radioanalytical and Nuclear Chemistry》2019,322(3):1273-1277
Journal of Radioanalytical and Nuclear Chemistry - Extraction chromatography flow-sheet employing octyl(phenyl)-N,N-diisobutylcarbonoylmethylphosphine oxide and bis(2-ethylhexyl) hydrogen phosphate... 相似文献
73.
By adapting the functional derivative method developed by Kadanoff and Baym to the Hubbard model, a new perturbation method is formulated. The unperturbed state is defined by the two equations which yield Hubbard's results, while the remainder is given by functional derivatives of the Green's functions which are shown to generate a complete perturbation series. Advantages of this method are discussed. 相似文献
74.
Asao Arai 《Letters in Mathematical Physics》2006,77(3):283-290
A quantum system of a Dirac particle interacting with the quantum radiation field is considered in the case where no external potentials exist. Then the total momentum of the system is conserved and the total Hamiltonian is unitarily equivalent to the direct integral
of a family of self-adjoint operators
acting in the Hilbert space
, where
is the Hilbert space of the quantum radiation field. The fiber operator
is called the Hamiltonian of the Dirac polaron with total momentum
. The main result of this paper is concerned with the non-relativistic (scaling) limit of
. It is proven that the non-relativistic limit of
yields a self-adjoint extension of a Hamiltonian of a polaron with spin 1/2 in non-relativistic quantum electrodynamics. 相似文献
75.
H. Kira Y. Sakaguchi T. Oku J. Suzuki M. Nakamura M. Arai K. Kakurai Y. Endo Y. Arimoto T. Ino H.M. Shimizu T. Kamiyama K. Tsutsumi K. Ohoyama H. Hiraka K. Yamada L.-J. Chang 《Physica B: Condensed Matter》2011,406(12):2433-2435
We have begun the development of an in-situ spin-exchange optical pumping (SEOP) system aiming to use it as a neutron spin filter for incident beam polarization at the Japan Proton Accelerator Research Complex (J-PARC). To use it, it is recommended that the optics be adjusted easily, have high stability, and have a small size. In this paper we improved our previous SEOP system aiming to use it in J-PARC and performed a neutron beam test at the JRR-3 NOP beamline to see the performance of the neutron spin filter (NSF). The polarization of the 3He gas reached 73%. This paper gives the present status of the development of in-situ SEOP system in J-PARC. 相似文献
76.
77.
78.
Suzuki T Arai K Goto H Hanano M Watanabe J Tomono K 《Chemical & pharmaceutical bulletin》2002,50(6):741-743
Nifedipine-containing calcium phosphate cement (CPC) was prepared, and nifedipine (NF) release from this preparation was evaluated by the shaking method (SK), Japanese Pharmacopoeia XIV (JPXIV) paddle method (PD), and JPXIV flow-through cell method (FT). The release of NF from the CPC preparation continued for 7 d or longer by all these methods. This suggests that the release of NF can be controlled by preparing NF-containing CPC. The release pattern of NF from CPC in these tests was found to follow the Higuchi equation. However, the Higuchi constant differed among the three dissolution tests, probably because the apparent tortuosity of capillary system (tau) varied. 相似文献
79.
Watanabe S Sonobe M Arai M Tazume Y Matsuo T Nakamura T Yoshida K 《Chemical communications (Cambridge, England)》2002,(23):2866-2867
A gold nanoparticle surface-modified with amide ligands shows enhanced optical sensing of anions: the detection limit is increased by about three orders of magnitude higher than that originally expected from the anion binding ability of neutral amide ligands. 相似文献
80.