Fluoride retention amounts following toothbrushing and mouthrinsing with a weak fluoride solution

Yiki Arakawa, Wenqun Song, Shinji Toda, Kazuaki Kawamura, Hirohisa Arakawa 대한임상예방치과학회 2009 International Journal of Clinical Preventive Denti Vol.5 No.1

Objectives: The aim of this study was to determine the effectiveness of caries prevention from intraoral fluoride retention following tooth brushing with a weak fluoride solution. Methods: Six subjects (average age is 37.5 years old) performed tooth brushing with a weak fluoride solution (100 ppm F as NaF) and fluoride mouth-rinsing (100 ppm F as NaF) as positive control just before going to bed on separate day. At the time of rising in the next morning, the subjects collected their unstimulated total saliva, and we examined salivary fluoride concentration. Two fluoride modalities were performed randomly each three times. Results: The mean salivary fluoride concentrations upon arising were 0.07 ppm (range: 0.01 - 0.22 ppm) in tooth brushing with a weak fluoride solution experiments and 0.14 ppm (range: 0.02 - 0.37 ppm) in fluoride mouth-rinsing experiments. Conclusion: Though salivary fluoride concentrations upon arising after tooth brushing with a weak fluoride solution was lower than after fluoride mouth-rinsing, it was higher than 0.05 ppm of optimal therapeutic level which enhances remineralization. The results suggested that tooth brushing with a weak fluoride solution just before going to bed was effective on caries prevention for young children. On the other hand, salivary fluoride concentrations after fluoride mouth-rinsing was significantly higher than tooth brushing with a weak fluoride solution, since fluoride might be reserved on oral mucous membrane.

Fluoride retention amounts following toothbrushing and mouthrinsing with a weak fluoride solution

Yuki Arakawa,Wenqun Song,Shinji Toda,Kazuaki Kawamura,Tomoka Kubota,Hirohisa Arakawa 대한예방치과학회 2009 International Journal of Clinical Preventive Denti Vol.5 No.2

Objectives: The aim of this study was to determine the effectiveness of caries prevention from intraoral fluoride retention following tooth brushing with a weak fluoride solution. Methods: Six subjects (average age is 37.5 years old) performed tooth brushing with a weak fluoride solution (100 ppm F as NaF) and fluoride mouth-rinsing (100 ppm F as NaF) as positive control just before going to bed on separate day. At the time of rising in the next morning, the subjects collected their unstimulated total saliva, and we examined salivary fluoride concentration. Two fluoride modalities were performed randomly each three times. Results: The mean salivary fluoride concentrations upon arising were 0.07 ppm (range: 0.01 - 0.22 ppm) in tooth brushing with a weak fluoride solution experiments and 0.14 ppm (range: 0.02 - 0.37 ppm) in fluoride mouth-rinsing experiments. Conclusion: Though salivary fluoride concentrations upon arising after tooth brushing with a weak fluoride solution was lower than after fluoride mouth-rinsing, it was higher than 0.05 ppm of optimal therapeutic level which enhances remineralization. The results suggested that tooth brushing with a weak fluoride solution just before going to bed was effective on caries prevention for young children. On the other hand, salivary fluoride concentrations after fluoride mouth-rinsing was significantly higher than tooth brushing with a weak fluoride solution, since fluoride might be reserved on oral mucous membrane. Objectives: The aim of this study was to determine the effectiveness of caries prevention from intraoral fluoride retention following tooth brushing with a weak fluoride solution. Methods: Six subjects (average age is 37.5 years old) performed tooth brushing with a weak fluoride solution (100 ppm F as NaF) and fluoride mouth-rinsing (100 ppm F as NaF) as positive control just before going to bed on separate day. At the time of rising in the next morning, the subjects collected their unstimulated total saliva, and we examined salivary fluoride concentration. Two fluoride modalities were performed randomly each three times. Results: The mean salivary fluoride concentrations upon arising were 0.07 ppm (range: 0.01 - 0.22 ppm) in tooth brushing with a weak fluoride solution experiments and 0.14 ppm (range: 0.02 - 0.37 ppm) in fluoride mouth-rinsing experiments. Conclusion: Though salivary fluoride concentrations upon arising after tooth brushing with a weak fluoride solution was lower than after fluoride mouth-rinsing, it was higher than 0.05 ppm of optimal therapeutic level which enhances remineralization. The results suggested that tooth brushing with a weak fluoride solution just before going to bed was effective on caries prevention for young children. On the other hand, salivary fluoride concentrations after fluoride mouth-rinsing was significantly higher than tooth brushing with a weak fluoride solution, since fluoride might be reserved on oral mucous membrane.

Development of Information System for Product Redesign: Evaluation of Assembly Process and Characteristics of Product Functions

Arakawa, Masahiro Korean Institute of Industrial Engineers 2010 Industrial Engineeering & Management Systems Vol.9 No.3

Since product design strongly depends on the experience and ability of the designers, and a long lead time is required for the product design stage, introducing a support system related to this experience and ability is an effective technique to reduce the lead time. In this paper, an information system is developed to support the development of engineering mechanisms with the evaluation of the assembly process on the basis of the abstract functions required for new products. The developed system is based on a database system involving the following data structure: (1) a hierarchical structure related to information about the product functions, (2) the relationship between the parts and engineering functions and/or mechanisms of products, and (3) the relationship between the parts and manufacturing characteristics. The system stores the relationships between the product functions, structure of parts, and assembly characteristics. This information can then be interactively retrieved using the data structure described in (1), (2), and (3). A procedure for designing new products is proposed that involves using the information about existing products. This paper presents the characteristics of the proposed procedure and the developed information system. In addition, a case study of the redesign of a simple structured robot by using the proposed procedure is discussed.

Radiation-training system with a custom survey-meter mock-up in a browser-based mixed reality environment

Arakawa Hiroyuki,Fujibuchi Toshioh,Kaneko Kosuke,Okada Yoshihiro,Tomisawa Toshiko 한국원자력학회 2024 Nuclear Engineering and Technology Vol.56 No.6

Training for radiation protection and control requires a visual understanding of radiation, which cannot be perceived by the human senses. Trainees must also master the effective use of measuring instruments. Traditionally, such training has exposed trainees to radiation sources. Here, we present a novel e-training strategy that enables safe, exposure-free handling of a radiation measuring tool called a survey meter. Our mixed reality radiation-training system merges the physical world with a digital one. Collaborating with a mixed reality headset (HoloLens 2), this system constructs a mock-up of a survey meter in real-world space. The HoloLens 2 employs a browser-based application to visualize radiation and to simulate/share the use of the survey meter, including its physical movements. To provide a dynamic learning experience, the system adjusts the surveymeter mock-up readings according to the operator’s movements, distance from the radiation source, the response time of survey meter, and shielding levels. Through this approach, we expect that trainees will acquire practical skills in interpreting survey-meter readings and gain a visual understanding of radiation in real-world situations.

ADVANCED SPACE PROPULSION ACTIVITIES IN JAPAN

Arakawa, Yoshihiro 한국 항공대학교 항공산업기술연구소 1994 航空宇宙産業技術硏究所 硏究誌 Vol.4 No.-

In ths seminar, the outline of advanced space propulsion sctivities in Japan is introduced. The National Space Development Agency of Japan(NASDA) is developing a high-performance liquid rocket engine for the first stage of the H-Ⅱ launch vehicle. The H-Ⅱ is designed to boost 2-tonne class satellites into geostationary orbit. The rocket engine, which is powered by liquid hydrogen and liquid oxygen and named LE-7, is a staged combustion-cycle engine capable of producing about 100-tonnes of thrust and a high impulse (450 sec in vacuum). The engine is manufactured by Mitsubishi Heavy Industries(MHI) and Ishikawajima Heavy Industries (IHI). Powering the second stage of the H-Ⅱ rocket is the LE-5A liquid engine which is an improved version of LE-5 that thas been used to drive the second stage of the H-I rocket. The LE-5A hydrogen/oxygen engine produces a thrust of 12 tonnes and has a restart capability. Japan is also developing high-performance electric thrusters which should be considered a replace technology in future space missions. Electric heating and/or by electrostatic and electromagnetic forces, produces much higher specific impulses than chemical propulsion. The specific impulse is typically ranged form 500 sec to 10,000sec. Such a high specific impulse produced by electric propulsion offers significant propellant mass saving compared to chemical propulsion. Japan covers a large variety of electric propulsion activities, on electrothermal propulsion(arcjet), electrostatic propulsion(Magneto Plasma Dynamic thruster), electrostatic propulsion(ion engine) and other types of thrusters, from fundamental studies to space flight tests. These activities have been performed by governmental research institutes, such as Institute of Space and Astronautical Science(ISAS), National Aerospace Laboratory(NAL), NASDA, and several universities. Several manufacturers such as Mitsubishi Electric Corporation, IHI, and Toshiba Corporation, join and support these activities. In the arcjet, propellant gas introduced in the electrode region is heated by electric are discharge and attain temperatures of 10,000K or more and expands into vacuum through a nozzle with super sonic flow. As the gas temperature is much higher than that of chemical propulsion, the arcjet produces relatively high specific impulses (500-2,000 sec). The energy conversion efficiency, which is defined as the ratio of jet power to electric input power, is around 30%, although is depends on power level, propellant type, etc. The present research in universities, research efforts are concentrated on the improvement of the efficiency and durability. A MPD thruster has been studied and developed in particularly in ISAS and universitis since 1970. Its thrust is produced mainly by electromagnetic forces due to discharge current and induced or externally applied magnetic field. The feature of this type is 1)easy to produce a high thrust density(high-power thruster), 2)a wide range of specific impulses(1,000-10,000 sec). A space test of a sub-kilowatts thruster designed in ISAS is planned to be conducted onbord a Japanese unmanned free flying platform, which will be launched by the H-Ⅱ rocket in early 1995. Tto improve the performance and to obtain scaling laws, much efforts are concentrated on the plasma acceleration mechanism and discharge phenomena. As for ion engine, this type of thruster is considered the most progressive one and will be operated in space for application to a station keeping of satellites and orbit maneuvering within several years. Ions produced in the discharge chamber are extracted and accelerated by electrostatic fields established between the grids to produce a thrust. Its energy conversion efficiency is in a high level(70-80%) at a specific impulse of more than 3,000 sec. NASDA is developing a 1kW-class ion engine system in cooperation with MHI to utilize it for the station keeping of ETS-Ⅳ satellite which will be launched in 1994. Endurance tests of several thousand hours were performed and are continued before the space flight.

Clinical Experience of High-flux Synthetic Membrane Hemodialysis

Arakawa, Masaaki . M.D 대한신장학회 2000 Kidney Research and Clinical Practice Vol.19 No.2

Regarding 'HPV Vaccination for Cervical Cancer Prevention is not Cost-effective in Japan'

Arakawa, Ichiro,Murasawa, Hideki,Konno, Ryo Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.6

Develoment and Clinical Application of New Biocompatible Membranes for Blood Filtration

Arakawa, Masaaki 대한신장학회 1991 Kidney Research and Clinical Practice Vol.10 No.3

Magnetic instability in Ca2−xSrxRuO4 with x = 0.5

Naoya Arakawa,Masao Ogata 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.3

We analyze the static susceptibilities for charge and spin degrees of freedom in Ca2−xSrxRuO4with x = 0.5 within the random phase approximation on the basis of the three-orbital Hubbardmodel for the Ru t2g orbitals. We find that the rotation of RuO6 octahedra, which is induced inthe range of x < 1.5, leads to the enhancement of several modes of spin fluctuation around bothq = (0, 0) and (, 0).

Efficient dye-sensitized solar cell sub-modules

Hironori Arakawa,Takeshi Yamaguchi,Takanori Sutou,Yutaro Koishi,Nobuyuki Tobe,Daisuke Matsumoto,Takuma Nagai 한국물리학회 2010 Current Applied Physics Vol.10 No.2

Two topics with dye-sensitized solar cell (DSC) development were introduced. The one was development of an efficient glass–substrate 10 cm-by-10 cm DSC sub-modules with current-collecting Ag grids using N719 dye (gac = 8.0%, Jsc = 16.8 mA/㎠, Voc = 0.71 V, ff = 0.67). Accelerated long-term stability tests were conducted using JIS C-8938 environmental and endurance test methods for amorphous-Si solar cell modules,which included a dry heat cycle test (-40 ℃ to 90 ℃, 200 cycles), a heat–humidity test (-40 ℃ to 90 ℃ with 85% humidity, 10 cycles) and a light-soaking test (255 W/m2 (300–700 nm), 500 h). The results suggested DSC using methoxypropionitrile (MPN) electrolyte solvent has a promising future to commercialization of DSC. The other was development of a new preparation method for highly efficient plastic–substrate DSC. This method consisted of important basic technologies such as press without heat treatment,light-confining effect by light scattering TiO2 large particles, binder-free water paste of TiO2 and UV–O3 treatment of TiO2 photoelectrode. The plastic–substrate DSC prepared by this new method showed a very high efficiency, 8.1% (0.29 ㎠) under simulated solar light (100 mW/㎠, AM1.5). Further,an efficient plastic–substrate 10 cm-by-10 cm DSC sub-module with current-collecting Ti grids using N719 dye (gac = 4.5%, Jsc = 10.9 mA/㎠, Voc = 0.72 V, ff = 0.57) was successfully prepared.