학술발표요지

Kang,Y S,K Hirai,H Sato,A Tsuji 한국약제학회 1987 Journal of Pharmaceutical Investigation Vol.17 No.4

The receptor-mediated degradation and internalization of insulin have been studied in vitro, while simple pharmacokinetic models have been used for in vivo analysis. However, no pharmacokinetic analysis of insulin has been performed using physiological and biochemical parameters, such as binding to plasma proteins transcapillary permeability, tissue blood flow. blood-to-plasma partition coefficient, and receptor binding. Therefore, we used [^(125)I-Tyr^(A14) human insulin which possesses the same biological activity as native insulin, and analysed the plasma and tissue concentration time-courses using a physiologically-based pharmacokinetic model. The results were as follows: 1. The total body clearance after i.v. injection of tracer insulin and excess amount of unlabelled insulin almost corresponded to the glomerular filtration rate(9.7㎖/min/㎏), and the volume of distribution was in agreement with extracellular space(250 ㎖/㎏). 2. There was no significant difference between the renal clearance of insulin and the glomerular filtration rate, and the total body clearance after i.v. injection of tracer insulin was nearly equal to the sum of the hepatic clearance and the glomerular filtration rate. 3. Under the consideration of these results, physiological parameters, such as the transcapillary permeability and the affinity constant and capacity for the receptor binding were calculated by a nonlinear least squares regression analysis(NONLIN 74). Transcapillary permeability of insulin has a good correlation with that of inulin in each tissue.

Wear Characteristics of Al-Si-Mg- (Cu)/Al2O3 Composites Fabricated by Thermit Reaction

Kim, S . W .,Woo, K . D .,Sato, T .,Na, H . S .,Kamio, A . 대한금속재료학회(대한금속학회) 2001 METALS AND MATERIALS International Vol.7 No.6

A₂O₃ particles could be formed by a thermit reaction in an Al-12Si-4Mg-1.5Cu/Al₂O₃ composite due to the in-situ reaction between Al-12Si-4Mg-(1.5Cu) molten metal and SiO₂ particles in preform, which took place at 1173 K for 24 hours, resulting in the decomposition of SiO₂ particles and the formation of Al₂O₃particles simultaneously. The mechanically mixed layers (MMLs) consisting of a-Fe and Fe oxides existed on the subsurface layers beneath the worn surface in composites or mother alloys, which improved the wear resistance. The characteristics of wear resistance and hardening of an Al-12Si-4Mg-1.5Cu/Al₂O₃ composite are superior to those of the Al-12Si-4Mg/Al₂O₃ composite and Al-12Si-4Mg-1.5Cu alloy.

Measurement of the lepton forward-backward asymmetry inB→Xsℓ+ℓ−decays with a sum of exclusive modes

Sato, Y.,Ishikawa, A.,Yamamoto, H.,Abdesselam, A.,Adachi, I.,Adamczyk, K.,Aihara, H.,Asner, D. M.,Aulchenko, V.,Aushev, T.,Ayad, R.,Bakich, A. M.,Bala, A.,Bhardwaj, V.,Bhuyan, B.,Bondar, A.,Bonvicini, American Physical Society 2016 Physical Review D Vol.93 No.3

<P>We report the first measurement of the lepton forward-backward asymmetry A(FB) as a function of the squared four-momentum of the dilepton system, q(2), for the electroweak penguin process B -> X(s)l(+)l(-) with a sum of exclusive final states, where l is an electron or a muon and X-s is a hadronic recoil system with an s quark. The results are based on a data sample containing 772 x 10(6) B (B) over bar pairs recorded at the gamma (4S) resonance with the Belle detector at the KEKB e(+)e(-) collider. A(FB) for the inclusive B -> X(s)l(+)l(-) is extrapolated from the sum of 10 exclusive X-s states whose invariant mass is less than 2 GeV/c(2). For q(2) > 10.2 GeV2/c(2), A(FB) < 0 is excluded at the 2.3 sigma level, where sigma is the standard deviation. For q(2) < 4.3 GeV2/c(2), the result is within 1.8 sigma of the standard model theoretical expectation.</P>

Measurement of the branching ratio of B¯0→D*+τ−ν¯τ relative to B¯0→D*+ℓ−ν¯ℓ decays with a semileptonic tagging method

Sato, Y.,Iijima, T.,Adamczyk, K.,Aihara, H.,Asner, D. M.,Atmacan, H.,Aushev, T.,Ayad, R.,Aziz, T.,Babu, V.,Badhrees, I.,Bakich, A. M.,Bansal, V.,Behera, P.,Bhardwaj, V.,Bhuyan, B.,Biswal, J.,Bonvicini American Physical Society 2016 Physical review. D Vol.94 No.7

<P>We report a measurement of the ratio R(D*) = B((B) over bar (0) -> D*(+)tau(-)(nu) over bar (tau))/B((B) over bar (0) -> D*(+)l(-)(nu) over bar (l))where l denotes an electron or a muon. The results are based on a data sample containing 772 x 10(6) B (B) over bar pairs recorded at the Upsilon(4S) resonance with the Belle detector at the KEKB e(+)e(-) collider. We select a sample of B-0(B) over bar (0) pairs by reconstructing both B mesons in semileptonic decays to D*(-/+)l(+/-). We measure R(D*) = 0.302 +/- 0.030(stat) +/- 0.011(syst), which is within 1.6 sigma of the Standard Model theoretical expectation, where the standard deviation sigma includes systematic uncertainties. We use this measurement to constrain several scenarios of new physics in a model-independent approach.</P>

Search for sub-GeV dark matter by annual modulation using XMASS-I detector

Kobayashi, M.,Abe, K.,Hiraide, K.,Ichimura, K.,Kishimoto, Y.,Kobayashi, K.,Moriyama, S.,Nakahata, M.,Ogawa, H.,Sato, K.,Sekiya, H.,Suzuki, T.,Takeda, A.,Tasaka, S.,Yamashita, M.,Yang, B.S.,Kim, N.Y.,K North-Holland Pub. Co 2019 Physics letters. Section B Vol.795 No.-

<P><B>Abstract</B></P> <P>A search for dark matter (DM) with mass in the sub-GeV region (0.32–1 GeV) was conducted by looking for an annual modulation signal in XMASS, a single-phase liquid xenon detector. Inelastic nuclear scattering accompanied by bremsstrahlung emission was used to search down to an electron equivalent energy of 1 keV. The data used had a live time of 2.8 years (3.5 years in calendar time), resulting in a total exposure of 2.38 ton-years. No significant modulation signal was observed and 90% confidence level upper limits of 1.6 × <SUP> 10 − 33 </SUP> cm<SUP>2</SUP> at 0.5 GeV was set for the DM-nucleon cross section. This is the first experimental result of a search for DM mediated by the bremsstrahlung effect. In addition, a search for DM with mass in the multi-GeV region (4–20 GeV) was conducted with a lower energy threshold than previous analysis of XMASS. Elastic nuclear scattering was used to search down to a nuclear recoil equivalent energy of 2.3 keV, and upper limits of 2.9 × <SUP> 10 − 42 </SUP> cm<SUP>2</SUP> at 8 GeV was obtained.</P>

Transcutaneous electrical nerve stimulation, acupuncture, and spinal cord stimulation on neuropathic, inflammatory and, noninflammatory pain in rat models

Karina Laurenti Sato,Luciana Sayuri Sanada,Morgana Duarte da Silva,Rodrigo Okubo,Kathleen A. Sluka 대한통증학회 2020 The Korean Journal of Pain Vol.33 No.2

Background: Transcutaneous electrical nerve stimulation (TENS), manual acupuncture (MA), and spinal cord stimulation (SCS) are used to treat a variety of pain conditions. These non-pharmacological treatments are often thought to work through similar mechanisms, and thus should have similar effects for different types of pain. However, it is unclear if each of these treatments work equally well on each type of pain condition. The purpose of this study was to compared the effects of TENS, MA, and SCS on neuropathic, inflammatory, and non-inflammatory pain models. Methods: TENS 60 Hz, 200 μs, 90% motor threshold (MT), SCS was applied at 60 Hz, an intensity of 90% MT, and a 0.25 ms pulse width. MA was performed by inserting a stainless-steel needle to a depth of about 4-5 mm at the Sanyinjiao (SP6) and Zusanli (ST36) acupoints on a spared nerve injury (SNI), knee joint inflammation (3% carrageenan), and non-inflammatory muscle pain (intramuscular pH 4.0 injections) in rats. Mechanical withdrawal thresholds of the paw, muscle, and/or joint were assessed before and after induction of the pain model, and daily before and after treatment. Results: The reduced withdrawal thresholds were significantly reversed by application of either TENS or SCS (P < 0.05). MA, on the other hand, increased the withdrawal threshold in animals with SNI and joint inflammation, but not chronic muscle pain. Conclusions: TENS and SCS produce similar effects in neuropathic, inflammatory and non-inflammatory muscle pain models while MA is only effective in inflammatory and neuropathic pain models.

Unraveling materials Berry curvature and Chern numbers from real-time evolution of Bloch states

Shin, Dongbin,Sato, Shunsuke A.,Hü,bener, Hannes,De Giovannini, Umberto,Kim, Jeongwoo,Park, Noejung,Rubio, Angel National Academy of Sciences 2019 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.116 No.10

<▼1><P><B>Significance</B></P><P>It was established by Thouless, Kohmoto, Nightingale, and den Nijs in 1982 that the topology of the solid-state wavefunctions leads to quantization of transverse electrical conductivity of an insulator. This recognition has led to the development of the new field of topological materials characterized by symmetry-protected quantum numbers. Here, we propose a general and computationally efficient framework enabling one to unveil and predict materials-topological invariants in terms of physical observables, such as the bulk time-dependent current. We show how the quantized charge and spin Hall effect appears even for materials with a non-Abelian Berry phase. This dynamical approach is not necessarily restricted to density functional theory, but can be extended to other schemes and to other methods dealing with correlations explicitly.</P></▼1><▼2><P>Materials can be classified by the topological character of their electronic structure and, in this perspective, global attributes immune to local deformations have been discussed in terms of Berry curvature and Chern numbers. Except for instructional simple models, linear response theories have been ubiquitously used in calculations of topological properties of real materials. Here we propose a completely different and versatile approach to obtain the topological characteristics of materials by calculating physical observables from the real-time evolving Bloch states: The cell-averaged current density reveals the anomalous velocities that lead to the conductivity quantum. Results for prototypical cases are shown, including a spin-frozen valley Hall and a quantum anomalous Hall insulator. The advantage of this method is best illustrated by the example of a quantum spin Hall insulator: The quantized spin Hall conductivity is straightforwardly obtained irrespective of the non-Abelian nature in its Berry curvature. Moreover, the method can be extended to the description of real observables in nonequilibrium states of topological materials.</P></▼2>

Numerical Simulations of Dry and Wet Deposition over Simplified Terrains

T. Michioka,H. Takimoto,A. Sato 한국대기환경학회 2017 Asian Journal of Atmospheric Environment (AJAE) Vol.11 No.4

To evaluate the deposition amount on a ground surface, mesoscale numerical models coupled with atmospheric chemistry are widely used for larger horizontal domains ranging from a few to several hundreds of kilometers; however, these models are rarely applied to high-resolution simulations. In this study, the performance of a dry and wet deposition model is investigated to estimate the amount of deposition via computational fluid dynamics (CFD) models with high grid resolution. Reynolds-averaged Navier-Stokes (RANS) simulations are implemented for a cone and a two-dimensional ridge to estimate the dry deposition rate, and a constant deposition velocity is used to obtain the dry deposition flux. The results show that the dry deposition rate of RANS generally corresponds to that observed in wind-tunnel experiments. For the wet deposition model, the transport equation of a new scalar concentration scavenged by rain droplets is developed and used instead of the scalar concentration scavenged by raindrops falling to the ground surface just below the scavenging point, which is normally used in mesoscale numerical models. A sensitivity analysis of the proposed wet deposition procedure is implemented. The result indicates the applicability of RANS for high-resolution grids considering the effect of terrains on the wet deposition.

Evaluating the activity of N-89 as an oral antimalarial drug

Nagwa S. M. Aly,Hiroaki Matsumori,Thi Quyen Dinh,Akira Sato,Shin-Ichi Miyoshi,장경수,유학선,Takaaki Kubota,Yuji Kurosaki,Duc Tuan Cao,Gehan A. Rashed,김혜숙 대한기생충학ㆍ열대의학회 2023 The Korean Journal of Parasitology Vol.61 No.3

Despite the recent progress in public health measures, malaria remains a troublesome disease that needs to be eradicated. It is essential to develop new antimalarial medications that are reliable and secure. This report evaluated the pharmacokinetics and antimalarial activity of 1,2,6,7-tetraoxaspiro[7.11]nonadecane (N-89) using the rodent malaria parasite Plasmodium berghei in vivo. After a single oral dose (75 mg /kg) of N-89, its pharmacokinetic parameters were measured, and t1/2 was 0.97 h, Tmax was 0.75 h, and bioavailability was 7.01%. A plasma concentration of 8.1 ng/ml of N-89 was maintained for 8 h but could not be detected at 10 h. The dose inhibiting 50% of parasite growth (ED50) and ED90 values of oral N-89 obtained following a 4-day suppressive test were 20 and 40 mg/kg, respectively. Based on the plasma concentration of N-89, we evaluated the antimalarial activity and cure effects of oral N-89 at a dose of 75 mg/kg 3 times daily for 3 consecutive days in mice harboring more than 0.5% parasitemia. In all the N-89- treated groups, the parasites were eliminated on day 5 post-treatment, and all mice recovered without a parasite recurrence for 30 days. Additionally, administering oral N-89 at a low dose of 50 mg/kg was sufficient to cure mice from day 6 without parasite recurrence. This work was the first to investigate the pharmacokinetic char-acteristics and antimalarial activity of N-89 as an oral drug. In the future, the following steps should be focused on developing N-89 for malaria treatments; its administration schedule and metabolic pathways should be investigated.

Time-dependent density functional theory of high-intensity short-pulse laser irradiation on insulators

Sato, S. A.,Yabana, K.,Shinohara, Y.,Otobe, T.,Lee, K.-M.,Bertsch, G. F. American Physical Society 2015 Physical review. B, Condensed matter and materials Vol.92 No.20