70 research outputs found

    Evaluation of forest decontamination using radiometric measurements

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    An experiment has been conducted to evaluate the additional dose reduction by clear felling contaminated forestry in Fukushima Prefecture, Japan, and using the timber to cover the areas with wood chips. A portable gamma spectrometry system, comprising a backpack containing a 3x3” NaI(Tl) detector with digital spectrometer and GPS receiver, has been used to map dose rate and radionuclide activity concentrations before, after and at stages during this experiment. The data show the effect of the different stages of the experiment on dose rate at different locations around the site. The spectrometric data have allowed the assessment of the contributions of natural and anthropogenic radionuclides to the dose rate at different parts of the site before and after the experiment. This has clearly demonstrated the value of radiometric methods in evaluating remediation, and the effect of other environmental processes. The value of spectrometric methods which directly measure radionuclide concentrations has also been shown, especially through the identification of the contribution of natural and anthropogenic activity to the measured dose rate. The experiment has shown that clearing trees and applying wood chips can reduce dose rates by 10-15% beyond that achieved by just clearing the forest litter and natural redistribution of radiocaesium

    Studies on Electrocardiograms of Fishes : II. ECG of Carp Recorded with Bipolar Lead from Body Surface

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    ECGs of various carp recorded with bipolar leads from certain positions on the body surface showed almost the same patterns. ECGs reco rded from pectoral fins, left and right fins connected with the plus and the minus terminals of ECG apparatus respectively, exhibited the upward or diphasic P wave and the QS or Qr or QR type of QRS complexes and ECGs from lower jaw (minus terminal) and either anal or caudal fin (plus terminal) showed the upward or diphasic P wave and the R or QS type of QRS complexes. It can therefore be presumed that in the case of carp heart the excitation spread through the atrium from dorsal to ventral direction radially and through the ventricle both from left to right and from basis to the apex

    Blood Corpuscle Resistance of Carp Died of Environmental Hypoxia and of Cyanide Poisoning

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    Blood corpuscle resistance (BCR) of carp significantly lowered immediately after death of environmental hypoxia from its normal level, while it remained at the same level as the normal one, when the fish was dead of cyanide poisoning. However, 24 hours after the fish was dead, the BCR decreased in the case of death of cyanide poisoning, whereas it increased in the case of death of environmental hypoxia, compared with its level immediately after the fish died. The results indicate that the measurement of BCR of fish within several hours after death may be applicable to judge whether the cause of fish death was the environmental hypoxia or not

    Relationship between the Concentration of Cyanide Ion Detected in Carp and That in Environmental Water

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    The toxicity of cyanide solution to carp increased with a rise in temperature. The result that the concentration of cyanide ion in blood was higher than that in hepatopancreas and spleen,or digestive tract of carp exposed to 10 ppm cyanide ion solution for 5 hours suggested that the ambient cyanide might enter into the blood through the gill. However, the cyanide ion concentration in skin and muscle was higher than that in viscera of carp died in 10 ppm cyanide ion solution. It can therefore be concluded that a large amount of cyanide penetrated into the fish body surface. Cyanide ion was detectable from carp washed by running tap water for 24 hours after death in 5 ppm cyanide ion solution , and also from carp exposed to 10 ppm cyanide ion solution for 70 minutes after death of suffocation

    A Consideration on the Relation of the Hemosiderosis in the Spleen of Fishes to the Waste from Chemical Plants

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    1. Histological examinations were made on the common gobbies, Acanthogobius flavimanus, collected in the period from November of 1972 to December of 1973, from two rivers, the Higashi-okawa and the Nishi-okawa. Both the rivers flow, at Kure City, Hiroshima Prefecture, into the Hiro Bay adjoining the Aki-nada in the Seto Inland Sea. The Higashi-okawa was expected to be severely polluted by the waste from big chemical plants built along its banks, whereas the Nishi-okawa was not. The results of the examinations were as follows; A manifest hemosiderosis was observed in the spleens of all specimens from the Higashi-okawa but no such symptom was found in those from the Nishi-okawa. These results suggested some relation between the hemosiderosis in the spleens of fishes and a pollution caused by waste from chemical plant. 2. A series of experiments on a laboratory scale were carried out on Tilapia mossambica, a euryhaline species easier to handle in a laboratory than the goby, for the purpose of verifying the above suggested relation of the hemosiderosis in the spleens of fishes to chemical pollution. The results were as follows; a) A hemosiderosis was observed markedly in the spleens of the animals which had been exposed for only one month to dilutions of the waste from the Fukuyama plant of the Nihon Kayaku K.K. though the animals could keep their vital and spawning functions at normal level for more than six months in these dilutions: The degree of development of hemosiderosis appeared to depend upon concentration of waste in the dilutions. A hematological examination on the animals which showed hemosiderosis in the spleens revealed a hypochromic and microcytic anemia. In the case of sudden death within 20 hours or so of exposure to dilutions of higher concentrations of waste, no hemosiderosis was found in the spleens of the animals, but other types of histopathological symptoms were noticed. b) Phenol, one of the principal components of the waste from the Fukuyama plant of the Nihon Kayaku K.K., was found to be the causing factor of the hemosiderosis in the spleen of the animal; when exposed to a phenol solution with a chronic toxic level of concentration (2 ppm), the animal showed a manifest hemosiderosis in the spleen. However, at higher concentration above the acute toxic level (50 ppm), the exposure of the animals to phenol solution did not result in the hemosiderosis in the spleen but in other types of histopathological symptoms. In conclusion, it should be emphasized that in the spleen of fishes exposed to waste from chemical plants, hemosiderosis will develop as a result of chronic hemolytic anemias even though the fishes themselves do not show any apparent abnormality, also that phenol can be one of the causes of such hemosiderosis

    Studies on Electrocardiograms of Fishes : I. Test of method to detect the ECG from fish

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    病態生理学的な目的で魚類のECGを解析する場合に最も適当な導出方法を得る為,従来の各種導出方法について吟味した. 露出心臓表面からのECG単極導出法 1) コイの露出心臓表面から単極導出法よりECGを記録した. 2) コイの露出心臓表面から得られたECGはP,QS群,Tの各波からなっており,その他の波は記録されなかった. 3) 心臓表面の各部位から得られたECGの波形と心室運動が停止した場合のECGに見られるQRS群,及びT波の消失から,P波は心房に,QRS群,及びT波は心室に由来する事を確認した. 体表面からのECG単極及び双極導出法 1) 麻酔したコイの体表面から単極導出法によって,比較的明瞭なECGを導出する事ができた. 2) 麻酔液を含む水を鰓に還流したコイの両胸鰭から双極導出法により,個体差の比較的少ない,安定したECGが得られた.従ってこの両胸鰭からの双極導出法は病態生理学的研究に用いる事が可能であろう. 体内(囲心腔)からのEC双極導出法 1) 電極をコイ,ニジマス,フナ,ハマチ,マダイの囲心腔内に挿入し,双極導出法によりECGを導出した. 2) 各魚種とも基線の動揺が少なく安定したECGが得られ,その波形はコイの胸鰭からの双極導出の場合と良く類似した. 3) この方法3),6)は電極を挿入する場合に魚体を傷つける,電極の挿入位置を正確に定める事が難しいなどの欠点があるが,心臓起電力が小さい魚や游泳状態にある魚からも安定したECGの導出が可能であり,魚類の病態生理学的研究,或は運動生理学的研究,さらには生態学的研究に現在,用いる事ができる最適の方法であるといえよう.Examinations have been made to find out the suitable method of detecting the ECG from fish for the purpose of pathological physiology study. The results obtained can be summarized as follows; Unipolar leads of ECG from the surface of the heart. ECGs, directly recorded on the surface of the Carp heart, consisted of P wave followed by QRS complex and a T wave (Fig. 4). Other waves derived from the heart could not be detected. Unipolar lead and bipolar lead of ECG from the body surface. i) ECG could be recorded from almost all the body surface of Carp by using unipolar lead. The amplitude of the QRS complex was about 40 µV in the vicinity of the heart. ii) ECGs obtained by using bipolar leads from pectoral fins of Carp were stable and the QRS complex appeared as a QS type ordinarily and exceptionally as a QR type. This method may be useful for the pathological physiology study of fish. The amplitude of QRS complex was 70 µV on the average. Bipolar lead of ECG from within the body. Electrodes were inserted into the chest with operation. ECGs by this method were easily detected from Carp, Crucian carp, Rainbow trout, Yellow tail, Sea bream under swimming condition in aquariums. The patterns of ECGs from the chest cavity were similar to those from pectoral fins of Carp. The amplitudes of the QRS complex were 1.12 mV in Carp, 0.40 mV in Crucian carp, 1.15 mV in Rainbow trout, 0.88 mV in Yellow tail, 0.12 mV in Sea bream. From the above results, it is apparent that the bipolar lead from the chest cavity is the most useful and suitable method to study fish ECG pathophysiologically and ecologically

    養殖ハマチの血液性状 : I. カタクチイワシ投餌の影響

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    養殖ハマチの主たる餌料であるカタクチイワシに起因する食餌性疾病の本態を究明するために,200尾のハマチにカタクチイワシを単一投与し,これを試験群とし,同時にイカナゴを単一投与した200尾のハマチを対照群として,50日間の飼育を行い,試験群に生ずる食餌性疾病の影響を血液性状,成長,肝蔵重量等について調べた.得られた結果を以下に示す. 1) 試験群では実験開始10日後には摂餌の不活発,成長の遅れ,軽度の肝萎縮等が認められ,20日後には食餌性疾病による斃死が始まり,実験終了時までに試験群の約50%が斃死した.斃死魚に見られる特徴は,体色の変化(主として黒変),肝萎縮,眼球突出などであった. 2) 試験群は血漿蛋白質量の減少及び低い血漿総コレステロール量を示したが,ヘモグロビン量及びヘマトクリット値については,斃死が盛んな時期においても,対照群に比較して有意な差を示さなかった. 3) 試験群においては,血漿蛋白質量の減少及びA/G比の変化から,グロブリン画分の減少が推測された. 4) ハマチの血漿蛋白質には電気泳動的に,6成分が認められ,両群においてIII画分の組成比の変化が認められた. 5) リポ蛋白質画分は対照群ではIV画分に相当したが,試験群では一定せず,III,IV,V,VI画分にわたり不明瞭な脂質の染色が認められた. 6) 試験群においては,セルローズアセテート膜上の,リポ蛋白質の染色が不明瞭である事,及び血漿総コレステロール量の減少から血漿脂質の減少が考えられた. 7) 試験群の脂質のTLCから,トリグリセライドの著しい減少と,それに相対的なワックスエステルの増加が認められた.Investigations have been carried out in view of verifying the effects of the disease caused by anchovy, Engraulis japonica, as a diet, on the blood properties of cultured yellow tail, Seriola quinqueradiata. Yearling yellow tail were fed for 50 days with two different diets, i.e. one was anchovy as an experimental diet and the other was sand launce, Ammodytes personatus, as control. The results can be summarized as follows: i) Fish fed on anchovy showed a loss of appetite and a retarding growth after about 10 days; exhibited abnormal swimming patterns, change of body color, and atrophy of the liver after about 20 days; mortality mounted to about 50% at the end of 50 days while that of control group remained at 5% level. The dead fish showed a remarkable change of body color, severe atrophy of the liver, and protrusion of the eye-balls. The liver weight of fish fed on anchovy was smaller than that of control fish. ii) Hemoglobin concentration and hematocrit value did not differ significantly in both groups. iii) Total plasma cholesterol concentration of fish fed on anchovy stayed almost unchanged with their growth, while those of the controls increased. iv) Total plasma protein and A/G ratio of fish fed on anchovy decreased with the progress of the disease. Those decreases both in total plasma protein concentration and A/G ratio indicated a decrease of globulin fraction. A/G ratio of control group, however, decreased more noticeably. v) Cellulose acetate electrophoresis separated the plasma protein of yellow tail into six major fractions. The electrophoretic pattern varied especially on plasma fraction III. vi) The main lipoprotein fraction agreed to the plasma fraction IV. Fish fed on anchovy freqnently lacked a lipoprotein corresponding to plasma fraction IV. vii) The considerable decrease of plasma lipid of the fish fed on anchovy was judged to be due to a lower degree of staining intensity for lipid and to the decrement of total plasma cholesterol concentration. viii) In the lipid classes of fish fed on anchovy, low proportions of triglycerides and phospholipids and high proportions of wax esters were noticed

    Isotopic signature and nano-texture of cesium-rich micro-particles: Release of uranium and fission products from the Fukushima Daiichi Nuclear Power Plant

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    Highly radioactive cesium-rich microparticles (CsMPs) released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) provide nano-scale chemical fingerprints of the 2011 tragedy. U, Cs, Ba, Rb, K, and Ca isotopic ratios were determined on three CsMPs (3.79–780 Bq) collected within ~10 km from the FDNPP to determine the CsMPs’ origin and mechanism of formation. Apart from crystalline Fe-pollucite, CsFeSi2O6 · nH2O, CsMPs are comprised mainly of Zn–Fe-oxide nanoparticles in a SiO2 glass matrix (up to ~30 wt% of Cs and ~1 wt% of U mainly associated with Zn–Fe-oxide). The 235U/238U values in two CsMPs: 0.030 (±0.005) and 0.029 (±0.003), are consistent with that of enriched nuclear fuel. The values are higher than the average burnup estimated by the ORIGEN code and lower than non-irradiated fuel, suggesting non-uniform volatilization of U from melted fuels with different levels of burnup, followed by sorption onto Zn–Fe-oxides. The nano-scale texture and isotopic analyses provide a partial record of the chemical reactions that occurred in the fuel during meltdown. Also, the CsMPs were an important medium of transport for the released radionuclides in a respirable form
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