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論文

Non-invasive imaging of radiocesium dynamics in a living animal using a positron-emitting $$^{127}$$Cs tracer

鈴井 伸郎*; 柴田 卓弥; 尹 永根*; 船木 善仁*; 栗田 圭輔; 保科 宏行*; 山口 充孝*; 藤巻 秀*; 瀬古 典明*; 渡部 浩司*; et al.

Scientific Reports (Internet), 10, p.16155_1 - 16155_9, 2020/10

 被引用回数:2 パーセンタイル:24.76(Multidisciplinary Sciences)

Visualizing the dynamics of cesium (Cs) is desirable to understand the impact of radiocesium when accidentally ingested or inhaled by humans. The positron-emitting nuclide $$^{127}$$Cs was produced using the $$^{127}$$I ($$alpha$$, 4n) $$^{127}$$Cs reaction, which was induced by irradiation of sodium iodide with a $$^{4}$$He$$^{2+}$$ beam from a cyclotron. We excluded sodium ions by using a material that specifically adsorbs Cs as a purification column and successfully eluted $$^{127}$$Cs by flowing a solution of ammonium sulfate into the column. We injected the purified $$^{127}$$Cs tracer solution into living rats and the dynamics of Cs were visualized using positron emission tomography; the distributional images showed the same tendency as the results of previous studies using disruptive methods. Thus, this method is useful for the non-invasive investigation of radiocesium in a living animal.

論文

Visualising spatio-temporal distributions of assimilated carbon translocation and release in root systems of leguminous plants

尹 永根*; 鈴井 伸郎*; 栗田 圭輔; 三好 悠太*; 海野 佑介*; 藤巻 秀*; 中村 卓司*; 信濃 卓郎*; 河地 有木*

Scientific Reports (Internet), 10, p.8446_1 - 8446_11, 2020/06

 被引用回数:10 パーセンタイル:60.52(Multidisciplinary Sciences)

根系からの放出物は根の位置によって異なり、同化炭素(C)の供給と密接に関係している。したがって、短時間での炭素の動きを定量化することで、根と土壌における炭素の代謝を明らかにできる可能性がある。$$^{11}$$CO$$_{2}$$と陽電子放出トレーサーイメージングシステムを使用し、根箱内における同化炭素の根系への移行を可視化するための非侵襲的な方法を確立した。$$^{11}$$C-光合成産物の移動と根系および土壌への放出の様子を、白ルーピンとダイズについて観察した。本手法により、根と土壌に分布する炭素配分の定量化が可能になった。これは、比較的短期間の環境条件に応じて、根-土壌系の特定の場所での炭素代謝と栄養循環の関係を解明するのに役立つ可能性がある。

論文

Corrigendum: Beam range estimation by measuring bremsstrahlung (2012 Phys. Med. Biol. 57 2843)

山口 充孝; 鳥飼 幸太*; 河地 有木; 島田 博文*; 佐藤 隆博; 長尾 悠人; 藤巻 秀; 国分 紀秀*; 渡辺 伸*; 高橋 忠幸*; et al.

Physics in Medicine & Biology, 61(9), p.3638 - 3644, 2016/05

 被引用回数:9 パーセンタイル:100(Engineering, Biomedical)

2012年にPhys. Med. Biol.誌にアクセプトされた原著論文("Beam range estimation by measuring bremsstrahlung", Phys. Med. Biol. 57 (2012) 2843)について、計算コードPHITSを用いた水中での炭素イオンの飛程に関して再計算したところ、飛程の値に間違いが見つかった。今後、制動輻射を用いたビームモニタリングに関する研究を行う上で無視することができない差異であるため、関連する記述内容も含め、訂正した原稿を投稿する。

論文

Non-invasive imaging of sodium dynamics in common reed using positron-emitting tracer imaging system

鈴井 伸郎; 丸山 哲平*; 河地 有木; 三輪 睿太郎*; 樋口 恭子*; 藤巻 秀

JAEA-Review 2015-022, JAEA Takasaki Annual Report 2014, P. 95, 2016/02

Common reed, which is classified to the same family as rice, is a salt-tolerant plant. In this study, we conducted non-invasive imaging of Na$$^{+}$$ dynamics in intact common reed plants by using $$^{22}$$Na tracer and a positron-emitting tracer imaging system (PETIS) in order to understand the salt-tolerant mechanism in common reed. Common reeds and rice plants were cultivated in a nutrient solution containing 50 mM NaCl. After $$^{22}$$Na was fed into the solution, we observed the $$^{22}$$Na movement from the solution to the shoot for 24 h using PETIS. As a result, $$^{22}$$Na was strongly accumulated in the shoot base but not transported to the upper shoot in common reed, whereas $$^{22}$$Na was continuously transported to the upper shoot in rice plant. Furthermore, we replaced the original solution with a fresh nutrient solution without $$^{22}$$Na and traced the $$^{22}$$Na movement inside the plants for 18 h. Detailed quantitative analysis of the image data revealed that $$^{22}$$Na migrated downward from the shoot base to the root tip in common reed. These results indicate that common reed has constitutive ability of Na$$^{+}$$ exclusion only in the direction of root tips, and consequently keeps low Na$$^{+}$$ concentration in the upper shoot.

論文

Imaging of radiocesium dynamics in soybean by using a high-resolution gamma camera

尹 永根; 河地 有木; 鈴井 伸郎; 石井 里美; 吉原 利一*; 渡部 浩司*; 山本 誠一*; 藤巻 秀

JAEA-Review 2015-022, JAEA Takasaki Annual Report 2014, P. 112, 2016/02

Large areas of agricultural fields were contaminated with radiocesium ($$^{134}$$Cs and $$^{137}$$Cs) in Japan by the accident of The Tokyo Electric Power Company Fukushima Daiichi Nuclear Power Station in March 2011. Many agricultural studies, such as fertilizer management and plant breeding, are undertaken for reducing radiocesium uptake in crops or enhancing of uptake and transportation via phytoremediation. These studies examine the control of radiocesium transport into/within plant bodies from the viewpoint of plant physiology. Radiotracer imaging is one of the few methods that enable the observation of the movement of substances in a living plant, like a video camera, without sampling of the plant tissues. In this study, we performed the imaging of $$^{137}$$Cs uptake and transport from root to aerial part by using a new gamma camera in intact soybean plants because contamination of soybean by radiocesium has currently become a major problem in agriculture in Fukushima.

論文

Development of a gamma camera system for high-energy gamma photon for quantitative observation of $$^{137}$$Cs movement in a plant body

河地 有木; 尹 永根; 鈴井 伸郎; 石井 里美; 吉原 利一*; 渡部 浩司*; 山本 誠一*; 藤巻 秀

JAEA-Review 2015-022, JAEA Takasaki Annual Report 2014, P. 94, 2016/02

We developed an original gamma camera system to image radiocesium in a plant. The gamma camera was designed for high-energy gamma photons from $$^{137}$$Cs radiocesium (662 keV). We performed tests to evaluate the position resolution and quantitative linearity of the gamma camera. The best spatial resolution of this gamma camera was determined to be 19.1 mm in full width at half maximum at the center of the field-of-view. And a result shows a quantitative linearity of the image data with a correlation of ${it r$^{2}$}$ = 0.9985 between the source activity and the count rate. We conclude the gamma camera system has sufficiently high capability to obtain quantitative and dynamic images of $$^{137}$$Cs movement in intact plants.

論文

Evaluation of the effect of elevated concentrations of CO$$_{2}$$ in a greenhouse for tomato cultivation

石井 里美; 山崎 治明*; 鈴井 伸郎; 尹 永根; 河地 有木; 島田 浩章*; 藤巻 秀

JAEA-Review 2015-022, JAEA Takasaki Annual Report 2014, P. 93, 2016/02

Tomato is popularly grown in environmentally controlled system such as a greenhouse for improvement of bioproduction. It is important to control the condition in the greenhouse for increasing the translocation of fixed carbon from the leaves to the growing fruits. Elevation of CO$$_{2}$$concentration is widely employed for that purpose; however, it is difficult to estimate its effect quantitatively because tomato plants have too large inter-individual variations with developing fruits. In this study, we employed a PETIS which is a live-imaging system of nutrients in plant body using short-lived radioisotopes including $$^{11}$$C. We also established a closed cultivation system to feed a test plant with CO$$_{2}$$ at set concentrations of 400, 1,500 and 3,000 ppm and a pulse of $$^{11}$$CO$$_{2}$$.

論文

Imaging of radiocesium uptake dynamics in a plant body by using a newly developed high-resolution gamma camera

河地 有木; 尹 永根; 鈴井 伸郎; 石井 里美; 吉原 利一*; 渡部 浩司*; 山本 誠一*; 藤巻 秀

Journal of Environmental Radioactivity, 151(Part 2), p.461 - 467, 2016/01

 被引用回数:14 パーセンタイル:42(Environmental Sciences)

We developed a new gamma camera specifically for plant nutritional research and successfully performed live imaging of the uptake and partitioning of $$^{137}$$Cs in intact plants. The gamma camera was specially designed for high-energy $$gamma$$ photons from $$^{137}$$Cs (662 keV). To obtain reliable images, a pinhole collimator made of tungsten heavy alloy was used to reduce penetration and scattering of $$gamma$$ photons. The array block of the GAGG scintillator was coupled to a high-quantum efficiency position sensitive photomultiplier tube to obtain accurate images. The completed gamma camera had a sensitivity of 0.83 count s$$^{-1}$$ MBq$$^{-1}$$ for $$^{137}$$Cs, and a spatial resolution of 23.5 mm. We used this gamma camera to study soybean plants that were hydroponically grown and fed with 2.0 MBq of $$^{137}$$Cs for 6 days to visualize and investigate the transport dynamics in aerial plant parts. $$^{137}$$Cs gradually appeared in the shoot several hours after feeding, and then accumulated preferentially and intensively in growing pods and seeds; very little accumulation was observed in mature leaves. Our results also suggested that this gamma-camera method may serve as a practical analyzing tool for breeding crops and improving cultivation techniques resulting in low accumulation of radiocesium into the consumable parts of plants.

論文

Detection of a gas region in a human body across a therapeutic carbon beam by measuring low-energy photons

山口 充孝; 長尾 悠人; 河地 有木; 佐藤 隆博; 藤巻 秀; 神谷 富裕; 鳥飼 幸太*; 島田 博文*; 菅井 裕之*; 酒井 真理*; et al.

International Journal of PIXE, 26(1&2), p.61 - 72, 2016/00

炭素線治療中にその軌道上の生体組織内で発生する局所的密度減少は、ブラッグピーク位置のシフトを引き起こし、誤照射の原因となる。この密度減少を炭素線照射中に確認できれば、誤照射を軽減する対策が立てられる。そこで、重粒子線治療で発生する二次電子による制動輻射のうち、発生量が多く効率的測定が可能な低エネルギー光子(63-68keV)による生体内の局所的密度減少の検出方法を開発している。今回、空気間隙による密度減少の存在の検出が可能かどうかをPHITSコードを用いたモンテカルロシミュレーションにより次のように評価した。ビーム軸方向の長さが50mm、奥行き200mm、高さ200mmのアクリルブロック2個を、ビーム軸方向に10mmの間隙を設けて設置した。また、検出器として、幅2.4mmのスリットを持つ鉛製コリメータとテルル化カドミウム製の検出素子を組み合わせた。炭素線を照射した際にビーム軸に対して垂直方向に放出される63-68keVの光子を検出したところ、その検出量に明らかな増減が確認できた。この結果は、間隙の存在を十分検出することが可能であることを示す。

論文

ナトリウム排除能が高いヨシ根におけるナトリウム下方移動の証明

樋口 恭子*; 藤巻 秀

Bio Industry, 32(12), p.46 - 52, 2015/12

最近我々は、$$^{22}$$NaトレーサとPositron-emitting Tracer Imaging System (PETIS)、および新たなデータ解析手法を用いて、耐塩性が高いことで知られるヨシの根では、侵入したNaが地上部に到達する前に回収され、根の先端に向かって送り返されていることを証明した。本解説ではこの研究の背景と意義、実験手法、将来展望について詳細に述べると共に、この手法が植物生理学および農学に対してもたらすであろう新たな展開についても提示する。

論文

Route and regulation of zinc, cadmium, and iron transport in rice plants (${it Oryza sativa}$ L.) during vegetative growth and grain filling; Metal transporters, metal speciation, grain Cd reduction and Zn and Fe biofortification

米山 忠克*; 石川 覚*; 藤巻 秀

International Journal of Molecular Sciences (Internet), 16(8), p.19111 - 19129, 2015/08

AA2015-0336.pdf:1.94MB

 被引用回数:98 パーセンタイル:82.78(Biochemistry & Molecular Biology)

Zinc (Zn), iron (Fe) concentrations in rice grains harvested under different levels in soil are known to change only within a small range, while cadmium (Cd) concentrations show greater changes. To clarify the mechanisms underlying such difference, we synthesized information on the routes of metal transport and accumulation in rice plants. At grain-filling, Zn and Cd ascending in xylem are transferred to the phloem at stem nodes. Grain Fe is largely derived from the leaves by remobilization. Zn and Fe concentrations in phloem-sap and grains are regulated within a small range, while Cd concentrations vary depending on xylem supply. To increase concentrations of the metal chelators are effective in increasing grain Zn and Fe concentrations. The elimination of OsNRAMP5 Cd-uptake transporter and the enhancement of root-cell vacuolar Cd sequestration reduce uptake and root-to-shoot transport, respectively, resulting in a reduction of grain Cd accumulation.

論文

放射性セシウムの植物体内移行のガンマカメラによる解析

藤巻 秀

放射線と産業, (138), p.25 - 28, 2015/06

放射性セシウムが、植物体においてどのように吸収され、移行・集積するのかという動態とそのメカニズム、あるいはその動態を変化させるような栽培条件や遺伝的条件は、ほとんど未解明である。こうした問題に対し我々は、従来、植物ポジトロンイメージング技術を用いて関心元素の動態解明を行ってきたが、セシウム137はポジトロン放出核種ではないため、この技術を適用することができなかった。そこで我々は、植物研究用の感度や解像度を持ち、セシウム137からのエネルギーの高い$$gamma$$線を画像化することのできる、世界初のガンマカメラを開発した。これにより、福島県をはじめとする複数の県で基準値超えの収穫物が見つかったことが問題となっているダイズを対象に、セシウム137の動きを追ったところ、予想された葉にではなく、成長中の莢(種子)に集中して移行することが明らかになった。このことは、ある種の輸送メカニズムが働いていることを示唆している。今後、そのメカニズムを司る遺伝子が明らかになり、さらにそれを品種改良などで人為的に変えられれば、より安心なダイズ栽培ができると考えている。

論文

半導体型積算線量計による環境放射能の測定,1; 従来測定法との比較による可能性評価

吉原 利一*; 長尾 悠人; 橋田 慎之介*; 河地 有木; 藤巻 秀

電力中央研究所報告(O14002), 19 Pages, 2015/05

従来法に比べて非侵襲的で、かつ労力等において有利な積算線量計を用いた方法により、環境中での樹体等からの放射能測定・汚染度推定が可能か明らかにすることを目的とした。千葉県我孫子市と東京都狛江市で生育するサクラとスギの樹体を対象として積算線量計による線量率等の測定を行い、以下の点を明らかにした。低バックグラウンド放射線量下でサクラ切断枝の放射線量測定値を検証した結果、樹体の遮蔽効果を仮定した補正値において従来手法と同等のBGとの差分の有意性、および採取地区間の有意差が確認できた。また、放射性Cs濃度とも相関が認められた。さらに、実環境下に生育するスギ立木の放射線量測定値を検証した結果、樹体の遮蔽効果を仮定した補正値においてとBGとの差分の有意性が認められた。一方、樹体内汚染分布等の影響を受け放射性Cs濃度との相関は大きく低下した。以上の結果、樹体の遮蔽効果・樹体内汚染分布等の適切な測定値の補正を行えば、積算線量計による環境中での樹体等からの放射能測定・汚染度推定が可能と考えられた。今後、樹体の遮蔽効果や樹体内汚染分布に関する補正精度の向上や、信頼限界の明示などを進め、森林管理などへの利用を図る。

論文

Base to tip and long-distance transport of sodium in the root of common reed [${it Phragmites australis}$ (Cav.) Trin. ex Steud.] at steady state under constant high-salt conditions

藤巻 秀; 丸山 哲平*; 鈴井 伸郎; 河地 有木; 三輪 睿太郎*; 樋口 恭子*

Plant & Cell Physiology, 56(5), p.943 - 950, 2015/05

 被引用回数:22 パーセンタイル:65.02(Plant Sciences)

耐塩性植物であるヨシおよび塩感受性植物であるイネにおけるナトリウムイオンの輸送の方向と割合を、放射性の$$^{22}$$Naトレーサとポジトロンイメージング技術を用いて解析した。まず、供試植物に50mMのNaClと微量の$$^{22}$$Naを含む水耕溶液を投与し、24時間栽培した。その後、$$^{22}$$Naを含まない水耕液に交換し、48時間栽培した。これらの栽培期間における$$^{22}$$Naの分布画像をポジトロンイメージング装置を用いて非破壊的かつ連続的に撮像したところ、ヨシでは根から吸収された$$^{22}$$Naは茎基部よりも上部に輸送されないことが確認された。さらに、$$^{22}$$Naを含まない水耕液に交換した後、$$^{22}$$Naが根元から根端に向けて0.5cm h$$^{-1}$$の速度で移動していることが確認された。一方、イネでは根から吸収された$$^{22}$$Naは連続的に地上部全体へと輸送されていた。これらの結果から、高塩濃度条件に晒されたヨシは、根元と茎基部においてナトリウムイオンを根端方向へと送り返していることが明らかとなった。このナトリウム排除機構により、ヨシは地上部のナトリウムイオン濃度を低く保ち、高い耐塩性を有していることが示唆された。

論文

Monitoring of positron using high-energy gamma camera for proton therapy

山本 誠一*; 歳藤 利行*; 小森 雅孝*; 森下 祐樹*; 奥村 聡*; 山口 充孝; 齋藤 勇一; 河地 有木; 藤巻 秀

Annals of Nuclear Medicine, 29(3), p.268 - 275, 2015/04

 被引用回数:18 パーセンタイル:66.34(Radiology, Nuclear Medicine & Medical Imaging)

In proton therapy, imaging of proton-induced positrons is a useful method to monitor the proton beam distribution after therapy. We developed a small field-of-view gamma camera for high-energy gamma photons and used it for monitoring the proton-induced positron distribution. The gamma camera used 0.85 mm $$times$$ 0.85 mm $$times$$ 10 mm GAGG pixels arranged in 20 $$times$$ 20 matrix to form a scintillator block, which was optically coupled to a 1-inch-square position-sensitive photomultiplier tube. The GAGG detector was encased in a 20-mm-thick container and a pinhole collimator was mounted on its front. The gamma camera had spatial resolution of approximately 6.7 cm and sensitivity of 3.2 $$times$$ 10$$^{-7}$$ at 1.2 m from the collimator surface. The gamma camera was set 1 m from the 35 cm $$times$$ 35 cm $$times$$ 5 cm plastic phantom in the proton therapy treatment room, and proton beams were irradiated to the phantom with two proton energies. For both proton energies, positron distribution in the phantom could be imaged by the gamma camera with 10-min acquisition. The lengths of the range of protons measured from the images were almost identical to the calculation. These results indicate that the developed high-energy gamma camera is useful for imaging positron distributions in proton therapy.

論文

Live-imaging evaluation of the efficacy of elevated CO$$_{2}$$ concentration in a closed cultivation system for the improvement of bioproduction in tomato fruits

山崎 治明*; 鈴井 伸郎; 尹 永根; 河地 有木; 石井 里美; 島田 浩章*; 藤巻 秀

Plant Biotechnology, 32(1), p.31 - 37, 2015/04

 被引用回数:15 パーセンタイル:53.84(Biotechnology & Applied Microbiology)

To maximize fruit yield of tomatoes cultivated in a controlled, closed system such as a greenhouse or a plant factory at a limited cost, it is important to raise the translocation rate of fixed carbon to fruits by tuning the cultivation conditions. Elevation of atmospheric $$^{11}$$CO$$_{2}$$ concentration is a good candidate. In this study, we employed a positron-emitting tracer imaging system (PETIS), which is a live-imaging technology for plant studies, and a short-lived radioisotope $$^{11}$$C to quantitatively analyze immediate responses of carbon fixation and translocation in tomatoes in elevated CO$$_{2}$$ conditions. We also developed a closed cultivation system to feed a test plant with CO$$_{2}$$ at concentrations of 400, 1500 and 3000 ppm and a pulse of $$^{11}$$CO$$_{2}$$. As a result, we obtained serial images of $$^{11}$$C fixation by leaves and subsequent translocation into fruits. Carbon fixation was enhanced steadily by increasing the CO$$_{2}$$ concentration, but the amount translocated into fruits saturated at 1500 ppm on average. The translocation rate had larger inter-individual variation and showed less consistent responses to external CO$$_{2}$$ conditions compared with carbon fixation.

論文

Common reed accumulates starch in its stem by metabolic adaptation under Cd stress conditions

樋口 恭子*; 金井 雅武*; 土屋 将久*; 石井 春香*; 渋谷 尚史*; 藤田 直子*; 中村 保典*; 鈴井 伸郎; 藤巻 秀; 三輪 睿太郎*

Frontiers in Plant Science (Internet), 6, p.138_1 - 138_6, 2015/03

 被引用回数:18 パーセンタイル:57.94(Plant Sciences)

In a previous study, we reported that the common reed accumulates water-soluble Cd complexed with an $$alpha$$-glucan-like molecule, and that the synthesis of this molecule is induced in the stem of the common reed under Cd stress. We studied the metabolic background to ensure $$alpha$$-glucan accumulation under the Cd stress conditions that generally inhibit photosynthesis. We found that the common reed maintained an adequate CO$$_{2}$$ assimilation rate, tended to allocate more assimilated $$^{11}$$C to the stem, and accumulated starch granules in its stem under Cd stress conditions. AGPase activity, which is the rate-limiting enzyme for starch synthesis, increased in the stem of common reed grown in the presence of Cd. Starch accumulation in the stem of common reed was not obvious under other excess metal conditions. Common reed may preferentially allocate assimilated carbon as the carbon source for the formation of Cd and $$alpha$$-glucan complexes in its stem followed by prevention of Cd transfer to leaves acting as the photosynthetic organ. These responses may allow the common reed to grow even under severe Cd stress conditions.

論文

Evaluation of velocity of $$^{11}$$C-photoassimilate flow using positron-emitting tracer imaging system

鈴井 伸郎; 河地 有木; 石井 里美; 尹 永根; 岩崎 郁*; 小川 健一*; 藤巻 秀

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 105, 2015/03

In this study, we developed an analytical method to evaluate velocity of photoassimilate flow using $$^{11}$$C-tracer and the positron-emitting tracer imaging system (PETIS). $$^{11}$$CO$$_{2}$$ gas tracer was fed to the compound leaves of the soybean plant, and serial images of $$^{11}$$C distribution were obtained by PETIS. Regions of interests (ROIs) were set in the node of the first compound leaf (ROI-1) and the stem base (ROI-2). Time course of $$^{11}$$C-radioactivity (Time-Activity Curve: TAC) in each ROI was generated from the serial images. Initial slope of the rising $$^{11}$$C-radioactivity was estimated by a linear least-square method using the TAC data. The value of the intercept of approximated line to the background line (X-intercept) was defined as "$$^{11}$$C-arrival time" to the ROIs. In order to determine X-intercept with a fair criterion, we developed an analytical program. The velocities of $$^{11}$$C-photoassimilate flows of 18 individual soybean plants were estimated by the values of $$^{11}$$C-arrival time and the distance between ROI-1 and ROI-2. As a result, the average value of the velocity was 113 cm h$$^{-1}$$ and the standard deviation was 20 cm h$$^{-1}$$. This result indicates the newly developed method is a reliable tool for the quantitative analysis of photoassimilate flow through the phloem.

論文

Ultra-high resolution of radiocesium distribution detection based on Cherenkov light imaging

山本 誠一*; 緒方 良至*; 河地 有木; 鈴井 伸郎; 尹 永根; 藤巻 秀

Nuclear Instruments and Methods in Physics Research A, 777, p.102 - 109, 2015/03

 被引用回数:3 パーセンタイル:26.04(Instruments & Instrumentation)

After the nuclear disaster in Fukushima, radiocesium contamination became a serious scientific concern and research of its effects on plants increased. In such plant studies, high resolution images of radiocesium are required without contacting the subjects. Cherenkov light imaging of beta radionuclides has inherently high resolution and is promising for plant research. Since $$^{137}$$Cs and $$^{134}$$Cs emit beta particles, Cherenkov light imaging will be useful for the imaging of radiocesium distribution. Consequently, we developed and tested a Cherenkov light imaging system. We used a high sensitivity cooled charge coupled device (CCD) camera for imaging Cherenkov light from $$^{137}$$Cs and $$^{134}$$Cs. A bright lens was mounted on the camera and placed in a black box. With a 100-$$mu$$m $$^{137}$$Cs point source, we obtained 220-$$mu$$m spatial resolution in the Cherenkov light image. With a 1-mm diameter, 320-kBq $$^{137}$$Cs point source, the source was distinguished within 2-s. We successfully obtained Cherenkov light images of a plant whose root was dipped in a $$^{137}$$Cs solution, radiocesium-containing samples as well as line and character phantom images with our imaging system. Cherenkov light imaging is promising for the high resolution imaging of radiocesium distribution without contacting the subject.

論文

Effects of glutathione concentration in the root zone and glutathione treatment period on cadmium partitioning in oilseed rape plants

中村 進一*; 近藤 ひかり*; 鈴井 伸郎; 尹 永根; 石井 里美; 河地 有木; 頼 泰樹*; 服部 浩之*; 藤巻 秀

Molecular Physiology and Ecophysiology of Sulfur, p.253 - 259, 2015/00

 被引用回数:3 パーセンタイル:71.16

Glutathione is a sulfur-containing peptide involved in various aspects of plant metabolism. Glutathione is also known to have effects on heavy metal responses in plants. In our previous work, we have found glutathione, applied to roots site- specifically, inhibited cadmium (Cd) translocation from roots to shoots and Cd accumulation in shoots in oilseed rape plants. In addition, we succeeded in visualizing inhibition of root-to-shoot translocation of Cd by using a positron-emitting tracer imaging system (PETIS). In this work, the effects of glutathione concentration in the root zone (hydroponic solution) and the glutathione treatment period on Cd partitioning in oilseed rape plants were investigated. Our experimental results demonstrated that glutathione, exceeding a certain concentration in the root zone, is needed to trigger inhibition of Cd translocation, and that treatment time from the start of glutathione application had different effects on Cd partitioning in oilseed rape plants.

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