著者

浜田 信行 ロイ E. ショア ローレンス T. ダウアー

出版者

日本保健物理学会

雑誌

保健物理 (ISSN:03676110)

巻号頁・発行日

vol.53, no.2, pp.47-64, 2018 (Released:2018-09-13)

参考文献数

60

被引用文献数

2 4

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For over four decades, a linear nonthreshold (LNT) model has been used for radiation protection purposes. In the United States of America, the National Council on Radiation Protection and Measurements (NCRP) established Scientific Committee 1-25 in 2015 to prepare a commentary to review recent epidemiologic data from studies with low doses or low dose rates and from the Life Span Study of atomic-bomb survivors to determine whether these epidemiologic studies broadly support the LNT model. In May 2018, NCRP published Commentary No. 27 “Implications of recent epidemiologic studies for the linear nonthreshold model and radiation protection”, noting that the ongoing development of science requires a constant reassessment of prior and emerging evidence to assure that the approach to radiation protection is optimal, even if not necessarily perfect. Based on the current epidemiological data, NCRP concluded that the LNT model (perhaps with excess risk estimates reduced by a dose and dose rate effectiveness factor) should continue to be utilized for radiation protection purposes. The Commentary will be used to support the work of NCRP Council Committee 1 who are charged to develop current radiation protection guidance for the United States, ultimately updating and expanding the basic radiation protection recommendations of NCRP Report No. 116 published in 1993. This review provides an outline and summary of the key points of NCRP Commentary No. 27.

著者

浜田 信夫 馬場 孝 佐久間 大輔

出版者

大阪市立自然史博物館

雑誌

大阪市立自然史博物館研究報告 = Bulletin of the Osaka Museum of Natural History (ISSN:00786675)

巻号頁・発行日

vol.75, pp.29-34, 2021-03-31

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2020年 7 月に発生した豪雨による球磨川氾濫で被害を受けた熊本県の人吉城歴史館の植物標本 を,乾燥・クリーニングする過程で,汚染カビの種類や性質について,14サンプルを調べた.最も多 く繁殖していたカビは,Trichoderma で,その他に,Fusarium,Penicillium などが検出された.いずれ も貧栄養な土壌中に一般的に見られる好湿性のカビであった.保存した植物標本に生育するカビには 好乾性カビは見つからなかったことから,いずれも洪水に由来し,浸水と同時に発生したカビと思わ れる.これらの汚染カビは,十分な乾燥を数カ月行えば,消失すると思われる.あわせて,乾燥や酸 素遮断を優先するカビ被害への初期対処法の提言も行った.

著者

浜田 信行

出版者

日本保健物理学会

雑誌

保健物理 (ISSN:03676110)

巻号頁・発行日

vol.53, no.2, pp.116-118, 2018 (Released:2018-09-13)

参考文献数

14

被引用文献数

1

著者

浜田 信行 吉永 信治

出版者

日本保健物理学会

雑誌

保健物理 (ISSN:03676110)

巻号頁・発行日

vol.53, no.3, pp.136-145, 2018 (Released:2018-11-27)

参考文献数

66

被引用文献数

1

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Ionizing radiation has long been indispensable in medicine. Such medical exposures can broadly be divided into two categories, namely, therapeutic exposures and diagnostic exposures. On one hand, therapeutic exposures generally occur at high dose and/or high dose rate, in which health effects of main concern are tissue reactions (formally called deterministic effects) and second cancer. Of these, mounting epidemiological evidence for tissue reactions has attracted particular attention to circulatory disease and cataracts. Diagnostic exposures, on the other hand, occur at relatively low dose and/or low dose rate, where cancer is the major health effect of concern. Epidemiological evidence from diagnostically exposed populations is still subject to uncertainties in dose (e.g., lack of individual doses) and potential biases (e.g., confounding by indication and reverse causation), which render direct risk estimation of diagnostic exposures unreasonable. This raises the need for the extrapolation from epidemiological evidence in other populations exposed to high dose and/or high dose-rate radiation. From radiation protection viewpoints, recent discussions include individual risk estimation, and individual radiation responses. This review paper provides a brief overview of recent topics in epidemiology and risk estimation for medical exposures.

著者

林田 敏幸 佐々木 洋 浜田 信行 立崎 英夫 初坂 奈津子 赤羽 恵一 横山 須美

出版者

日本保健物理学会

雑誌

保健物理 (ISSN:03676110)

巻号頁・発行日

vol.52, no.2, pp.88-99, 2017 (Released:2017-07-29)

参考文献数

54

被引用文献数

5

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In March 2011, the accident occurred at the Fukushima Daiichi Nuclear Power Plant of Tokyo Electric Power Company. During recovery from critical situations, the radiation dose for some emergency workers exceeded the effective dose limit recommended for an emergency situation. A month after the accident, the International Commission on Radiological Protection issued a statement on tissue reactions recommending significant reduction of the equivalent dose limit to the lens of the eye. Many radiation workers will need to be involved in treatment of water contaminated with radionuclides, fuel debris retrieval, and decommissioning of reactors for a long period of time. Thus, the optimized radiation control in the fields, exposure reduction, prevention of tissue reactions, and reduction of stochastic risks for workers becomes necessary. This paper discusses issues in relation to radiation protection of the ocular lens in such recovery workers, from the viewpoint of radiation exposure of workers, its management, manifestations and mechanisms of the lens effects.

著者

藤通 有希 小佐古 敏荘 吉田 和生 浜田 信行

出版者

日本保健物理学会

雑誌

保健物理 (ISSN:03676110)

巻号頁・発行日

vol.48, no.2, pp.86-96, 2013 (Released:2014-03-06)

参考文献数

57

被引用文献数

3 2 1

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The International Commission on Radiological Protection (ICRP) has classified radiation cataract as tissue reactions (formerly known as deterministic effects or non-stochastic effects) for which a threshold dose exists, and recommended an equivalent dose limit for the lens of the eye to prevent vision-impairing cataracts. A recommended occupational dose limit has been 150 mSv/year predicated on the threshold of >8 Sv since the 1980 Brighton Statement, but was drastically lowered by the 2011 Seoul Statement to 20 mSv/year, averaged over defined periods of 5 years, with no single year exceeding 50 mSv. Such a new limit was included immediately in the Interim Edition of General Safety Requirements Part 3 of the International Atomic Energy Agency. In contrast, a dose limit of 15 mSv/year for members of the public has not been changed since the 1990 Recommendations. This paper considers the impacts of a new limit focusing on conformity with cancer risk management, the necessity of the public dose limit in planned exposure situations and the occupational dose limit in emergency exposure situations. Potential issues arising from its implementation shall also be discussed especially in terms of the compensation problem and the possibility of exceeding a dose limit in interventional cardiologists.

著者

武村 雅之 浜田 信生

出版者

公益社団法人 日本地震学会

雑誌

地震 第2輯 (ISSN:00371114)

巻号頁・発行日

vol.49, no.2, pp.141-168, 1996-08-23 (Released:2010-03-11)

参考文献数

35

被引用文献数

1

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96 photographs of seismograms from the 1923 Kanto earthquake (M=7.9) have been preserved at JMA (the Japan Meteorological Agency). These seismograms were obtained at meteorological observatories in and around Japan and Tohoku Imperial University in Sendai, whose epicentral distances are within about 2000km. P-wave forms of the main shock are recorded at 37 observation stations, though larger shaking parts of the ground motions are saturated on the records at almost all the stations. First, a type of seismograph and its instrumental characteristics are examined for each record from old materials and old records preserved at JMA. It is found that the seismograms at 29 stations were recorded by Portable Seismographs with natural period T of about 5sec and magnification V of 10 to 100, and most of the others by Omori's Seismographs with T of 10 to 30sec and V of 10 to 20 and by Wiechert Seismographs with T of about 5sec and V of about 100. Secondly, P-wave characteristics of each record are examined. We reexamined polarities of initial P-wave motions and reviewed focal mechanisms obtained for the Kanto earthquake. We also found that P-wave forms at many stations have some characteristics in common. The P-waves begin with small amplitude and the first remarkable phase with a large amplitude appears after the duration of the initial small phases. The second remarkable phase is also identified several seconds after the first remarkable phase, irrespective of the epicentral distances of the stations. The duration time τ01 of the initial small amplitudes correlates with the epicentral distance at each station. It can be explained by the difference of calculated arrival times between Pn and Pg phases or between Pn and P* phases in addition to a duration of the initial small rupture near the hypocenter. The duration of the initial small rupture is evaluated about 4.5sec from τ01's at observation stations within the epicentral distance of 170km. In the meantime, the difference τ12 of arrival times between the first and the second remarkable phases correlates with the azimuth angle of each station from the epicenter. Geometry and difference of occurrence times of big subevents are evaluated on the fault plane of the main shock from the data of τ12's, if we assume the two remarkable phases are due to two big subevents, respectively. The second subevent is located about 40km distant from the first subevent in the direction of about N 100°E, and the time interval of the occurrences of the two subevents is about 14sec.

著者

草野 富二雄 浜田 信生

出版者

公益社団法人 日本地震学会

雑誌

地震 第2輯 (ISSN:00371114)

巻号頁・発行日

vol.44, no.4, pp.305-313, 1991-12-24 (Released:2010-03-11)

参考文献数

34

被引用文献数

2

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The focal process of the 1964 Niigata Earthquake was reinvestigated on the basis of hypocentral distribution of its aftershocks. This study indicates that the aftershocks are distributed on a fault plane dipping westward.Although it has been clear that the fault strike of the mainshock was in N20°E direction, the dip of the fault was not still clear due to a poor resolution of hypocenter of aftershocks. To resolve the difficulty, we reexamined seismological data obtained by the Japan Meteorological Agency (JMA).Reexamination of seismograms of nearby stations enabled us to supplement more than 1200 new P and S arrivals of aftershocks. We also dentified a number of P and S arrivals from the data which were previously reported as unidentified phases. The Joint Hypocenter Determination method was used to get a more reliable aftershocks distribution. The number of located aftershocks much increased, as about 380 aftershocks are well located by this study.Aftershocks on the vertical cross section which is normal to the fault strike shows that aftershocks are on a westward dipping plane. The dip of the plane is estimated as 50 degrees which is consistent with the focal mechanisms reported by several studies. Although the dip angle depends on the velocity model used in hypocenter location, westward dipping of aftershocks is valid, independent of several different velocity models. Therefore we estimate that the subduction of the Japan Sea under the north-east Honshu does not occur in the southern part of the eastern margin of the Japan Sea.The aftershock activity is found to be low around the hypocenter of mainshock which is located near the bottom of aftershock region, suggesting a large strain release around the nucleation point of mainshock. Relative position of forerunning seismic activity which preceded the mainshock by two years seems to be within the shallow part of the aftershock region east of Awashima-island which is located in the western middle of the focal region. The epicentral distribution of aftershocks indicates that aftershock occurrence is scarce around Awashima-island. A similar relation was reported in the case of the 1983 Nihonkai-chubu earthquake between its aftershocks and Kyurokujima-island, which is situated east of the middle of the aftershock region. Few aftershocks occurred in the area around Kyurokujima-island. In spite of the difference in relative location, that is, Awashima is situated west of the aftershock region while Kyurokujima is in the east, this suggests possibilities that crust around the islands cannot sustain enough strain to generate aftershocks or it behave as an earthquake barrier.

著者

浜田 信夫 田口 淳二 佐久間 大輔

出版者

大阪市立自然史博物館

雑誌

大阪市立自然史博物館研究報告 = Bulletin of the Osaka Museum of Natural History (ISSN:00786675)

巻号頁・発行日

no.77, pp.29-36, 2023-03-31

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博物館の乾燥菌類標本のカビ汚染について調査を行ったところ,カビはDNAとして検出されるが,現在生存していないことが明らかになった.そこで,過去に採集,乾燥,標本の作製,保存のどの段階で,どの程度カビ汚染が起きたかについて,博物館に収蔵されているAmanita属36標本のカサの部分を用いて検証した.手法としては,2種のカビの作成したプライマーを用いて,各検体のカビ数をリアルタイムPCRで測定し,その胞子数を調査した.得られた結果は次の通りであった.①両種の胞子数は標本ごとに桁違いのバラツキがあった.②検出されたA. penicillioidesの胞子数は,標本の乾重量100 mg当たり平均約1000個, Eurotium sp. は約7個であった.③結果は,採集時からの様々な過程で,湿り気が発生し,標本上にカビが一時的に発生したことを示唆している.なお,産出された胞子数は標本の古さ,あるいは目視でのカビの有無とは関係ないので,保存前の段階で汚染がしばしば起きたと推測される.

著者

上野 寛 森 博一 碓井 勇二 宮村 淳一 吉川 一光 浜田 信生

出版者

特定非営利活動法人 日本火山学会

雑誌

火山 (ISSN:04534360)

巻号頁・発行日

vol.47, no.5, pp.689-694, 2002-11-29 (Released:2017-03-20)

参考文献数

14

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We studied high-frequency earthquake swarm associated with the eruption of the Usu volcano in 2000 using the data observed by a national seismic network in southern Hokkaido. To get a precise hypocenter location, we applied the double-difference method and station correction to hypocenter determination. Systematic shift of epicenters possibly caused by heterogeneous velocity structure of the upper crust is needed to be consistent with the initial motions of the seismograms at the nearest station. Concentration of hypocenters under the northern flank of the volcano in the initial stage suggests that the magma started its activity at about 5 km in depth at the region. Concentric expansion of swarm area occurred before the eruption and formed doughnut pattern of which center is located near the summit of the volcano. Doughnut pattern may represent relaxation of stress under the volcano which is caused by magma movement and pore pressure change under the volcano.

著者

三宅 香 熊田 秀文 二瓶 智太郎 大橋 桂 清水 統太 好野 則夫 浜田 信城 寺中 敏夫

出版者

特定非営利活動法人 日本歯科保存学会

雑誌

日本歯科保存学雑誌 (ISSN:03872343)

巻号頁・発行日

vol.56, no.5, pp.461-467, 2013-10-31 (Released:2017-04-28)

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目的:超高齢社会への進展に伴い,高齢者の口腔粘膜疾患の予防および治療法が重要視されている.そのなかでも高齢者に増加傾向のある口腔カンジダ症は,基礎疾患や免疫不全の患者における誤嚥性肺炎の誘発率が高く,直接死につながる疾患として歯科領域の急務の対策課題である.そこでわれわれは,義歯などの技工物表面に発症するカンジダ症を含む口腔感染症の予防および治療対策として,材料表面への抗菌性の付与を目的とした第4級アンモニウム塩の構造を有する新規の抗菌性シランカップリング剤N-allyl-N-decyl-N-methyl-N-trimethoxysilylpropylammonium iodide(10-I)を開発した.本研究では,口腔常在微生物のカンジダ菌,歯周病原細菌および齲蝕病原細菌を含む8菌株を供試し,10-Iの最小発育阻止濃度(MIC)測定および10-I塗布材料表面の接触型抗菌活性を測定して,その有用性を評価した.材料と方法:BHI-yeast寒天培地および血液寒天培地に10-Iの濃度が100,200,400,600ppmおよび800ppmになるよう加え,各供試菌懸濁液10μlを播種し,好気性菌は37℃,24時間,嫌気性菌は37℃,72時間培養し,コロニー発育が観察されなかった培地の最小化合物濃度をMIC値とした.次いで1.1×104,1.1×105,6.2×107CFU/mlに調製したCandida albicansを4ml,10-Iで表面改質したガラス板を1枚ずつ加え,一定振盪下で37℃,24時間好気的に培養した.培養後,各ウェルの生菌数を計測し,対照ウェルの菌数と実験ウェルの菌数の割合を比較して減少率を求め,抗菌活性とした.結果:MIC測定では,Actinomyces viscosus, Fusobacterium nucleatum, Lactobacillus casei, Porphyromonas gingivalisおよびPrevotella intermediaの5菌株に対してはおのおの200ppm,一方,C. albicans, Staphylococcus aureusおよびStreptococcus mutansは400ppmであった.また,C. albicansに対する10-I処理面の接触型抗菌活性測定では,10-I処理面の生菌数の減少率は1.1×104CFU/mlでは92.5%であり,明らかな減少傾向が認められた.結論:以上の結果より,10-Iは供試したすべての口腔細菌およびカンジダ菌に対して抗菌活性を示したことから,10-Iによる表面処理は,高齢者や免疫機能低下者などにみられる口腔固有の菌が起因となる歯科疾患のみならず,誤嚥性肺炎などの全身疾患の併発の抑制,あるいは予防につながると考えられ,有効な手段であることが示唆された.

著者

浜田 信行

出版者

日本保健物理学会

雑誌

保健物理 (ISSN:03676110)

巻号頁・発行日

vol.52, no.2, pp.77-87, 2017 (Released:2017-07-29)

参考文献数

37

被引用文献数

4

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In April 2011, the International Commission on Radiological Protection recommended reducing the occupational equivalent dose limit for the lens of the eye. Since then, discussions toward implementation of such a revised dose limit into national law have been made in various countries. In the United States of America (US), the National Council on Radiation Protection and Measurements (NCRP) established Scientific Committee 1-23 (SC 1-23) in January 2014 to provide guidance on whether existing dose limits for the ocular lens should be changed in the US, to which the author of this paper served as Consultant. In January 2017, NCRP published Commentary No. 26 “Guidance on radiation dose limits for the lens of the eye” which was prepared by SC 1-23. With this Commentary, NCRP now recommends reducing the occupational dose limit for the lens from equivalent dose of 150 mSv/year to absorbed dose of 50 mGy/year along with the use of relative biological effectiveness value for high linear energy transfer radiation. This review provides an outline of this Commentary.

著者

赤羽 恵一 飯本 武志 伊知地 猛 岩井 敏 大口 裕之 大野 和子 川浦 稚代 立崎 英夫 辻村 憲雄 浜田 信行 藤通 有希 堀田 豊 山崎 直 横山 須美

出版者

日本保健物理学会

雑誌

保健物理 (ISSN:03676110)

巻号頁・発行日

vol.49, no.3, pp.153-156, 2014 (Released:2015-07-18)

参考文献数

14

被引用文献数

3 2

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A brief review is given of the history and methodology of external dosimetry for the lens of the eye. Under the 1989 revision to domestic radiological protection regulations, the concept on the effective dose equivalent and the dose limit to the lens of the eye (150 mSv/y) both introduced in the ICRP 1977 recommendations has changed nationwide the external monitoring methodology in non-uniform exposure situations to the trunk of a radiological worker. In such situations, which are often created by the presence of a protective apron, the worker is required to use at least two personal dosemeters, one worn on the trunk under the apron and the other, typically, at the collar over the apron. The latter dosemeter serves the dual purpose of providing the dose profile across the trunk for improved effective dose equivalent assessment and of estimating the dose to lens of the eye. The greater or appropriate value between Hp(10) and Hp(0.07), given by the dosemeter, is generally used as a surrogate of Hp(3) for recording the dose to the lens of the eye. The above-mentioned methodology was continued in the latest 2001 revision to the relevant regulations.

著者

赤羽 恵一 飯本 武志 伊知地 猛 岩井 敏 大口 裕之 大野 和子 川浦 稚代 立崎 英夫 辻村 憲雄 浜田 信行 藤通 有希 堀田 豊 山崎 直 横山 須美

出版者

日本保健物理学会

雑誌

保健物理 (ISSN:03676110)

巻号頁・発行日

vol.50, no.2, pp.128-137, 2015 (Released:2016-01-09)

参考文献数

8

被引用文献数

2

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While the revised dose limit for the lens of the eye was presented by the International Commission on Radiological Protection (ICRP), the dose measurement standards for the lens of the eye have been discussed in the International Organization for Standardization (ISO). In the International Basic Safety Standards of International Atomic Energy Agency (IAEA), a new ICRP dose limit of the lens of the eye was included, and a technical document was published as a guidance on the implications of the new dose limit for the lens of the eye for occupational radiation protection. By the International Radiation Protection Association (IRPA) Task Group on Implementation of Revised Dose Limits to the Lens of the Eye, the opinions for the new ICRP dose limit for the lens of the eye are investigated for the member states. In this paper, the progress of discussion in these organizations is reported.

著者

赤羽 恵一 飯本 武志 伊知地 猛 岩井 敏 大口 裕之 大野 和子 川浦 稚代 立崎 英夫 辻村 憲雄 浜田 信行 藤通 有希 堀田 豊 山崎 直 横山 須美

出版者

日本保健物理学会

雑誌

保健物理 (ISSN:03676110)

巻号頁・発行日

vol.50, no.1, pp.76-89, 2015 (Released:2015-12-18)

参考文献数

52

被引用文献数

2 4

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For many Japanese radiation workers in the medical, nuclear and other industrial fields, the equivalent dose of the lens of the eye will be sufficiently lower than the new ICRP dose limit. However, the dose of the lens of the eye for medical staff members who are engaged in interventional radiology and cardiology may exceed the new ICRP dose limit, especially when they are exposed closely to higher scatter radiation for a long time. In addition, the radiation dosimetry and radiation protection for emergency and recovery workers in the Fukushima Daiichi Nuclear Power Plant (FNPP1) are important issues. Thus gathering information related to the radiation dose and protection for Japanese radiation workers is important to a discussion regarding implementation of the new ICRP dose limit for the lens of the eye for Japanese regulations and planning radiation dose reduction measures. In this paper, recent studies and issues regarding radiation exposure and protection in the medical, nuclear and other industrial fields, as well as for emergency and recovery workers in the FNPP1 were summarized.

著者

赤羽 恵一 飯本 武志 伊知地 猛 岩井 敏 大口 裕之 大野 和子 川浦 稚代 立崎 英夫 辻村 憲雄 浜田 信行 藤通 有希 堀田 豊 山崎 直 横山 須美

出版者

日本保健物理学会

雑誌

保健物理 (ISSN:03676110)

巻号頁・発行日

vol.50, no.1, pp.67-75, 2015 (Released:2015-12-18)

参考文献数

40

被引用文献数

3

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The International Commission on Radiological Protection (ICRP) and the International Commission on Radiation Units and Measurements (ICRU) have been defined operational quantities and protection quantities. Dose limits have been also recommended by the ICRP using protection quantities. These quantities and some related values for main radiation such as photons, electrons, and neutrons, are summarized in this article with some historical considerations. The ICRP indicated conversion coefficients for the lens of the eye as absorbed dose per fluence as protection quantities. Equivalent dose is not used because a protection quantity that uses radiation weighting factors is not intended to be calculated for tissue reactions. So far, the ICRP has not indicated a specific RBE value for cataract formation. Operational quantities are used for measurements. There have been three types of phantoms, namely a slab phantom, a reduced phantom, and a cylindrical phantom, but none of them has been definitely recommended for the lens of the eye by the ICRP or the ICRU. Although conversion coefficients to personal dose equivalent, Hp(3), for electrons have been recommended, no other conversion coefficients to personal dose equivalent for the lens of the eye has been indicated by the ICRP or the ICRU. However, there have been several studies described personal dose equivalent. Ambient dose equivalent, H*(3), and directional dose equivalent, H'(3,a), have been indicated in several limited conditions by the ICRP and the ICRU. These status are overviewed in this article.

著者

浜田 信生

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.110, no.2, pp.132-144, 2001-04-25 (Released:2009-11-12)

参考文献数

20

被引用文献数

5 4

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Based on macro seismic and instrumental observation data covering a period of over hundred years, the characteristics of seismic activity around Miyakejima, Kozushima, and Niijima, the northern Izu islands, were investigated. Seismic activity is distributed along the Zenisu ridge and the Nishi-Shitito ridge to the west and along Niijima, Miyakejima, Mikurajima and Hachijojima islands to the east. Most of the seismic activity in the region is of the swarm type and is often induced by a large earthquake or magmatic activity at Miyakejima and other volcanoes. Comparison of macro-seismic data of large earthquakes in the late 1800s and the early 1900s with a seismic intensity map of recent earthquakes suggested that the maximum size of an earthquake in the region is around a magnitude of 6.5 on the JMA magnitude scale. Linear arrangements of seismicity in the NE-SW direction, which is parallel with the Zenisu ridge, and in the NW-SE direction, which is almost normal to the former and parallel to the direction of the plate motion of the Philippine Sea plate, are often recognized. While the strike slip-type earthquake with a NE-SW tension axis is predominant in the region along Niijima, Miyakejima, Mikurajima, and Hachijojima islands, a strike slip with E-W tension axis is predominant in the region along the Zenisu ridge and the Nishi-Shitito ridge. A complex tectonic setting of the region, back arc spreading, collision of the Philippine Sea plate to the Eurasian plate around the Izu peninsula, deformation of the plate due to the subduction of slab from the Suruga and the Sagami trough, must shape the characteristics of seismic activity in the region such as the upper limit of earthquake scale, swarm-type activity, close relation with volcanic activity, and regional stress pattern.

著者

藤通 有希 小佐古 敏荘 吉田 和生 浜田 信行

出版者

日本保健物理学会

雑誌

保健物理 (ISSN:03676110)

巻号頁・発行日

vol.48, no.2, pp.97-103, 2013 (Released:2014-03-06)

参考文献数

25

被引用文献数

2 1 1

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Radiation cataract has been classified as tissue reactions (formerly known as deterministic effects or non-stochastic effects) with a threshold dose. In 1984, the International Commission on Radiological Protection (ICRP) suggested the threshold dose of >8 Sv for vision-impairing cataracts in highly fractionated or protracted exposures. Such a threshold was used to recommend an occupational dose limit for the lens of 150 mSv/year in 1990 and 2007, but was reduced to 0.5 Sv in 2011 for all exposure scenarios irrespective of the rate of dose delivery. New threshold was determined on the basis of the limited human evidence, with various hypotheses not supported by the present knowledge of biological mechanisms. Examples of untested hypotheses include: (a) radiation cataract is a tissue reaction; (b) radiation damage to the large number of cells acts as a triggering event for radiation cataract; (c) detectable minor opacities progress into vision-impairing cataracts with time; and (d) the lower the dose, the longer the latency. This paper discusses the issues behind the scientific basis for the new threshold, and provides directions for future epidemiological and biological studies to establish the reasonably modeled dose-response relationship for radiation cataract.

著者

浜田 信夫

出版者

日本菌学会

雑誌

日本菌学会大会講演要旨集 環境微生物系学会合同大会2017

巻号頁・発行日

pp.84, 2017 (Released:2018-03-30)

著者

石井 信之 浜田 信城 渡辺 清子

出版者

一般社団法人 日本歯内療法学会

雑誌

日本歯内療法学会雑誌 (ISSN:13478672)

巻号頁・発行日

vol.29, no.1, pp.26-29, 2008 (Released:2017-12-30)

参考文献数

10

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Abstract : Hypochlorous acid is a weak acid with the chemical formula HClO. It forms when chlorine dissolves in water. HClO is an acid involving a polyatomic ion. HClO is used as a bleach, oxidizer, deodorant, and disinfectant. CampherTM contains 80% HClO and is used as a food disinfectant, deodorant, air cleaner, and in instrument and package cleaner systems. The purpose of this study was to examine the efficacy of CampherTM as a root canal irrigant in endodontics. Both pH 6.5 and pH 7.0 CampherTM were examined for bactericidal effect and cytotoxicity. Obligative anaerobic bacteria were completely inhibited by applying CampherTM for 1 minute, and facultative bacteria was inhibited 10−2~10−3 by CampherTM for 1 minute in bactericidal effect. The growth of oral epithelial cells was not affected by CampherTM for 48 hours. Both bactericidal effect and cytotoxicity did not vary with the different pH of CampherTM. These results suggested that CampherTM has a bactericidal effect and no cytotoxicity, and could be useful as a root canal irrigant.