Water-soluble photoluminescent carbon dots prepared from phloroglucinol by catalyst- and solvent-free reaction

Gohda Syun,Ono Hironobu,Yamada Yasuhiro 한국탄소학회 2023 Carbon Letters Vol.33 No.2

Carbon dots (CDs) were synthesized from phloroglucinol (PG) by simple heat treatment at 220–230 °C in the atmosphere without catalysts and solvents. PG-CDs heated at 220–230 °C could be completely dissolved in environmentally friendly water and exhibited a photoluminescence (PL) peak at 485 nm with 85 nm of the full width at half maximum (FWHM). The water-soluble polymer-dot-like PG-CDs were estimated to be 1.6–3.2 nm in size, and exhibited a wide range of PL wavelength at 370–630 nm. Since the PG-CDs are water-soluble materials, PG-CDs could be homogeneously mixed with a polymer such as polyvinylpyrrolidone (PVP) in water as a solvent, and PG-CDs/PVP films were prepared. The films exhibited PL characteristics that convert ultraviolet light at 350 nm to visible light above 400 nm. Thus, using PG as the raw material which has widely been produced industrially, the water-soluble fluorescent PG-CDs/PVP films could be prepared at a low cost by environmentally friendly methods.

Synthesis of carbon materials with extremely high pyridinic-nitrogen content and controlled edges from aromatic compounds with highly symmetric skeletons

Taguchi Taisei,Gohda Syun,Gotoh Kazuma,Sato Satoshi,Yamada Yasuhiro 한국탄소학회 2023 Carbon Letters Vol.33 No.4

Selective doping of pyridinic nitrogen in carbon materials has attracted attention due to its significant properties for various applications such as catalysts and electrodes. However, selective doping of pyridinic nitrogen together with controlling skeletal structure is challenging in the absence of catalysts. In this work, four precursors including four fused aromatic rings and pyridinic nitrogen were simply carbonized in the absence of catalysts in order to attain mass synthesis at low cost and a high percentage of pyridinic nitrogen in carbon materials with controlled edges. Among four precursors, dibenzo[f,h]quinoline (DQ) showed an extremely high percentage of pyridinic nitrogen (96 and 86%) after heat treatment at 923 and 973 K, respectively. Experimental spectroscopic analyses combined with calculated spectroscopic analyses using density functional theory calculations unveiled that the C-H next to the pyridinic nitrogen in DQ generated gulf edge structures with controlled pyridinic nitrogen after carbonization. By comparing the reactivities among the four precursors, three main factors required for maintaining the pyridinic nitrogen in carbon materials with controlled edges, such as (1) high thermal stability of the pyridinic nitrogen, (2) the presence of one pyridinic nitrogen in one ring, and (3) the formation of gulf edges including pyridinic nitrogen to protect the pyridinic nitrogen by the C-H groups on the gulf edges, were revealed.

Disturbance Attenuation Fictitious Reference Iterative Tuning Using Frequency Domain Approach

Shiro Masuda,Yuki Gohda,Yoshihiro Matsui 제어로봇시스템학회 2014 제어로봇시스템학회 국제학술대회 논문집 Vol.2014 No.10

The paper gives a design method for a Fictitious Reference Iterative Tuning (FRIT) method for disturbance attenuation which can be designed using the frequency domain approach. The proposed method obtains the control parameters that optimize a performance index represented in the frequency domain, which evaluates how the closed loop frequency response is close to the ideal one in the presence of a given deterministic disturbance. The frequency domain performance index for the FRIT method consists of the Fourier transformation of oneshot experimental input-output data and disturbance signal. The paper shows that a band-path filter plays an important role in the Fourier transformation of the one-shot inputoutput data, and the optimal pre-filter, which well approximates the performance index to the original performance index, can be easily calculated in the frequency domain. Finally, numerical examples show that the control parameter tuning using frequency domain FRIT method with the optimal prefilter contributes to deriving a better control parameters which improve the disturbance response.

Beneficial effects of tonsillectomy plus steroid pulse therapy on inflammatory and tubular markers in patients with IgA nephropathy

( Shuntaro Maruyama ),( Tomohito Gohda ),( Yusuke Suzuki ),( Hitoshi Suzuki ),( Yuji Sonoda ),( Saki Ichikawa ),( Zi Li ),( Maki Murakoshi ),( Satoshi Horikoshi ),( Yasuhiko Tomino ) 대한신장학회 2016 Kidney Research and Clinical Practice Vol.35 No.4

Background: IgA nephropathy (IgAN) is the most common form of primary glomerulonephritis worldwide. Tonsillectomy plus steroid pulse therapy has been able to induce clinical remission in early-stage IgAN. However, its possible effect on systemic and local cytokines and tubular markers has not been fully investigated. Methods: We obtained serum and urine samples from 38 patients just before renal biopsy and third steroid pulse therapy. Markers of tubular damage such as N-acetyl-β- D-glucosaminidase, and kidney injury molecule-1 and inflammation such as interleukin (IL)-6, monocyte chemotactic protein (MCP)-1, intercellular adhesion molecule (ICAM)-1, and vascular cell adhesion molecule (VCAM)-1 were measured by immunoassay. Results: Before renal biopsy, only urinary inflammatory markers, except MCP-1, were associated with glomerular (proteinuria) and/or tubular damage markers. Proteinuria, hematuria, and estimated glomerular filtration rate dramatically improved after therapy. In addition, levels of serum IL-6 and ICAM-1 and all urinary markers declined significantly; however, serum MCP-1 and VCAM-1 levels did not. None of the urinary markers correlated with the serum inflammatory markers. Conclusion: Tonsillectomy plus steroid pulse therapy for patients with IgAN might be useful for improving not only glomerular damage marker but also tubular damage markers through the improvement of local renal inflammation. Copyright ⓒ 2016. The Korean Society of Nephrology. Published by Elsevier. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

거제도 남쪽해역에서 쌍방향 음파전파 해양음향 토모그래피를 이용한 유속측정

Byun, Sang-Kyung,Kim, Bong-Chae,Cnoi, Bok-Kyoung,Kaneko, Arata,Gohda, Noriaki 한국해양학회 1999 바다 Vol.4 No.3

해양음향 토모그래피에 의한 유속측정의 유효성을 검증하기 위하여 1997년 4월 거제도 남쪽해역에서 쌍방향 음파전파 토모그래피 실험을 실시하였다. 이 실험은 해양음향 토모그래피에 의한 실시간 유속관측 시스템을 구축하기 위한 현장 기초실험으로 시도되었다. 실험 당시의 해양물리 환경을 고려하면서 음파 전파시간 차이에 의한 유속측정 결과를 초음파 유속계(ADCP)에 의한 실측유속과 비교 분석하였다. 그 결과 두 실측치는 상관계수 0.943으로써 매우 양호한 상관관계를 보였으며, 해양음향 토모그래피에 의한 방법이 연안해역에서 유속측정 방법으로서 향후 크게 활용될 수 있으리라 판단된다. In order to investigate the validity of acoustic tomography for current measurement, an experiment of reciprocal sound transmission was conducted in April, 1997 in the southern water of Koje island. This experiment was attempted as a preliminary field study on coastal ocean acoustic tomography for construction of real-time current observation system. Examining the physical oceanography environments, the current data obtained by travel time difference of reciprocal sound wave was compared with the data of Acoustic Doppler Current Profiler (ADCP). The result shows the correlation coefficient of 0.943, very good relation between the two data, and therefore the ocean acoustic tomography could be a useful method for current measurement in the coastal area.

Discovery of New Fusion Inhibitor Peptides against SARS-CoV-2 by Targeting the Spike S2 Subunit

( Mahmoud Kandeel ),( Mizuki Yamamoto ),( Hideki Tani ),( Ayako Kobayashi ),( Jin Gohda ),( Yasushi Kawaguchi ),( Byoung Kwon Park ),( Hyung-joo Kwon ),( Jun-ichiro Inoue ),( Abdallah Alkattan ) 한국응용약물학회 2021 Biomolecules & Therapeutics(구 응용약물학회지) Vol.29 No.3

A novel coronavirus, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), caused a worldwide pandemic. Our aim in this study is to produce new fusion inhibitors against SARS-CoV-2, which can be the basis for developing new antiviral drugs. The fusion core comprising the heptad repeat domains (HR1 and HR2) of SARS-CoV-2 spike (S) were used to design the peptides. A total of twelve peptides were generated, comprising a short or truncated 24-mer (peptide #1), a long 36-mer peptide (peptide #2), and ten peptide #2 analogs. In contrast to SARS-CoV, SARS-CoV-2 S-mediated cell-cell fusion cannot be inhibited with a minimal length, 24-mer peptide. Peptide #2 demonstrated potent inhibition of SARS-CoV-2 S-mediated cell-cell fusion at 1 μM concentration. Three peptide #2 analogs showed IC50 values in the low micromolar range (4.7-9.8 μM). Peptide #2 inhibited the SARSCoV- 2 pseudovirus assay at IC50=1.49 μM. Given their potent inhibition of viral activity and safety and lack of cytotoxicity, these peptides provide an attractive avenue for the development of new prophylactic and therapeutic agents against SARS-CoV-2.

Kuroshio Observation Program: Towards Real-Time Monitoring the Japanese Coastal Waters

Ostrovskii, Alexander,Kaneko, Arata,Stuart-Menteth, Alice,Takeuchi, Kensuke,Yamagata, Toshio,Park, Jae-Hun,Zhu, Xiao Hua,Gohda, Noriaki,Ichikawa, Hiroshi,Ichikawa, Kaoru,Isobe, Atsuhiko,Konda, Masanor Korea Institute of Ocean Science Technology 2001 Ocean and Polar Research Vol.23 No.2

The challenge of predicting the Japanese coastal ocean motivated Frontier Observational Research System for Global Change (FORSGC) and the Japan Marine Science and Technology Center (JAMSTEC) to start a multiyear observational programme in the upstream Kuroshio in November 2000. This field effort, the Kuroshio Observation Program (KOP), should enable us to determine the barotropic and baroclinic components of the western boundary current system, thus, to better understand interactions of the currents with mesoscale eddies, the Kuroshio instabilities, and path bimodality. We, then, will be able to improve modeling predictability of the mesoscale, seasonal, and inter-annual processes in the midstream Kuroshio near the Japanese main islands by using this knowledge. The KOP is focused on an enhanced regional coverage of the sea surface height variability and the baroclinic structure of the mainstream Kuroshio in the East China Sea, the Ryukyu Current east of the Ryukyu's, and the Kuroshio recirculation. An attractive approach of the KOP is a development of a new data acquisition system via acoustic telemetry of the observational data. The monitoring system will provide observations for assimilation into extensive numerical models of the ocean circulation, targeting the real-time monitoring of the Japanese coastal waters.