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1.
J Environ Radioact ; 278: 107486, 2024 Jun 26.
Article de Anglais | MEDLINE | ID: mdl-38936250

RÉSUMÉ

After the Fukushima Daiichi nuclear power plant accident, the terrestrial environment became severely contaminated with radiocesium. Consequently, the river and lake water in the Fukushima area exhibited high radiocesium levels, which declined subsequently. The partition coefficient of 137Cs between the suspended sediment (SS) and dissolved phases, Kd, was introduced to better understand the dynamic behavior of 137Cs in different systems. However, the Kd values in river water, ranging from 2 × 104 to 7 × 106 L kg-1, showed large spatiotemporal variability. Therefore, the factors controlling the 137Cs partition coefficient in natural water systems should be identified. Herein, we introduce a chemical model to explain the variability in 137Cs Kd in natural water systems. The chemical model includes the complexation of Cs+ with mineral and organic binding sites in SS, metal exchange reactions, and the presence of colloidal species. The application of the chemical model to natural water systems revealed that Cs+ is strongly associated with binding sites in SS, and a major chemical interaction between 137Cs and the binding sites in SS is the isotope exchange reaction between stable Cs and 137Cs, rather than metal exchange reactions with other metal ions such as potassium ions. To explain the effect of the SS concentration on Kd, the presence of colloidal 137Cs passing through a filter is significant as the dominant dissolved species of 137Cs in river water. These results suggest that a better understanding of stable Cs dissolved in natural water is important for discerning the geochemical and ecological behaviors of 137Cs in natural water.

2.
J Obstet Gynaecol Res ; 49(3): 1007-1011, 2023 Mar.
Article de Anglais | MEDLINE | ID: mdl-36631946

RÉSUMÉ

AIM: Even though 95% of struma ovarii are benign, it is often overtreated because of the difficulty to distinguish it from malignancy. In this study, our aim was to evaluate the current state of the preoperative diagnosis and the selection of the surgical procedure, and to improve preoperative diagnostic accuracy by retrospectively reviewing imaging findings. METHODS: We retrospectively reviewed the clinical course and imaging characteristics of 18 patients who were diagnosed postoperatively with struma ovarii, pathologically, at our institution between 2015 and 2021. RESULTS: The preoperative diagnoses included benign ovarian tumor in eight cases, borderline in four cases, and malignant in six cases. None of the cases were diagnosed as struma ovarii preoperatively. Of the seven patients who had confirmed a desire for future childbearing, four patients were suspected for borderline or malignant tumor preoperatively, and underwent abdominal adnexectomy. In patients without a desire for childbearing, laparoscopic surgery was performed in only 45% of the patients whose preoperative diagnosis was benign. On magnetic resonance imaging (MRI), 54% of the cases showed enhanced solid components, which is characteristic of malignant tumors, but diffusion restriction was observed in only 11%. On computed tomography (CT), 78% of the cases showed a high attenuation lesion reflecting thyroid tissue. CONCLUSIONS: Struma ovarii is difficult to distinguish from malignancy preoperatively, making the choice of surgical approach complicated. A comprehensive evaluation of diffusion-weighted MRI and CT findings may improve the accuracy of preoperative diagnosis of struma ovarii.


Sujet(s)
Tumeurs de l'ovaire , Goitre ovarien , Femelle , Humains , Goitre ovarien/diagnostic , Goitre ovarien/anatomopathologie , Goitre ovarien/chirurgie , Études rétrospectives , Tumeurs de l'ovaire/anatomopathologie , Tomodensitométrie , Imagerie par résonance magnétique
3.
Radiat Prot Dosimetry ; 198(13-15): 1170-1174, 2022 Sep 09.
Article de Anglais | MEDLINE | ID: mdl-36083733

RÉSUMÉ

According to the observed data of the activity concentration of $^{137}$Cs in Lake Onuma on Mount. Akagi, located in Gunma Prefecture, the decrease of the activity concentration slowed down since 2 years after the accident of Fukushima Daiichi Nuclear Power Plant. In the present study, we applied the time fractional diffusion equation to reproduce long-term changes in the time series of the activity concentration. In addition, we also reproduced the vertical distribution of the activity concentration with the parameter values, estimated by the time series data. We found that the model fit the observed data well for both time series and vertical distribution.


Sujet(s)
Accident nucléaire de Fukushima , Contrôle des radiations , Polluants radioactifs de l'eau , Radio-isotopes du césium/analyse , Japon , Centrales nucléaires , Polluants radioactifs de l'eau/analyse
4.
Sci Rep ; 11(1): 20336, 2021 10 13.
Article de Anglais | MEDLINE | ID: mdl-34645862

RÉSUMÉ

The Fukushima Daiichi Nuclear Power Plant accident also contaminates lakes in Japan. Especially in closed lakes, there is a problem of prolonged low-level [Formula: see text]Cs contamination because the activity concentration of [Formula: see text]Cs declines sharply immediately after the accident, but then begins to decrease slowly. In this paper, we derived a long-term prediction formula based on the fractional diffusion model (FDM) for the temporal variation in [Formula: see text]Cs activity concentrations of the water in Lake Onuma on Mt. Akagi, one of the closed lakes, and of pond smelt (Hypomesus nipponensis), a typical fish species inhabiting in the lake. The formula reproduced well the measured [Formula: see text]Cs activity concentration of the lake water and pond smelt for 5.4 years after the accident. Next, we performed long-term prediction for 10,000 days using this formula and compared it with the prediction results of the two-component decay function model (TDM), which is the most common model. The results suggest that the FDM prediction will lead to a longer period of contamination with low-level [Formula: see text]Cs than the TDM prediction.

5.
Diabetol Int ; 11(4): 299-308, 2020 Oct.
Article de Anglais | MEDLINE | ID: mdl-33088634

RÉSUMÉ

The Japan Diabetes Society's Committee to Promote Female Diabetologists conducted a questionnaire survey from May to June 2017 to investigate the work style and living situation of diabetologists. The survey targeted 5298 Board Certified Diabetologists (diabetologists), with answers obtained from 1566 diabetologists (male, n = 1003: females, n = 563). Ninety-four percent of the males and 72% of the females worked full time. Twenty-one percent of the male subjects and 7% of the female subjects were heads of clinical departments, and 23% of the male subjects and 13% of the female subjects were diabetes training instructors, showing that there were fewer women than men in both roles. Regarding the allocation of time per day, men spent 10.7 h working, while women spent 8.5 h working. Both men and women slept 6.3 h. Men spent 1.0 h on housework, while women spent 3.3 h on housework. Men spent 0.7 h on childcare and nursing care, while women, spent 2.8 h. Among diabetologists in the childrearing generation, men spent 1.4 h providing childcare and nursing care, while women spent 4.9 h, showing that women spent significantly more time on these tasks than men. To encourage female diabetologists to work more actively, to reduce overworking on the part of male diabetologists, and to enhance the careers of both men and women as diabetologists, we conclude it necessary to improve the workplace environment and for the Japan Diabetes Society to offer support.

6.
J Environ Radioact ; 218: 106257, 2020 Jul.
Article de Anglais | MEDLINE | ID: mdl-32421578

RÉSUMÉ

We describe here a first attempt to estimate the water seepage rate of an active crater lake using radioactive cesium dispersed into the environment by the Fukushima Dai-ichi Nuclear Power Plant accident in March 2011 as a hydrological tracer. Kusatsu-Shirane volcano is one of the most active volcanoes in Japan and has an active crater lake named Yugama. There is no outflow such as a river from Yugama crater lake. The content level of stable cesium (133Cs) in Yugama water was almost constant at 15-20 nM during the sampling period of Nov. 2011 to Nov. 2014. In contrast to 133Cs, however, the radioactive cesium (134Cs and 137Cs) concentrations in Yugama water decreased at a more rapid rate than expected by radioactive decay. Based on the decreasing rates of activity concentrations of 134Cs and 137Cs in Yugama water during the three years between 2012 and 2014, it is estimated that 700-800 m3 of the Yugama water, which corresponds approximately to 0.1% of the total volume, leaks through the lakebed per day. In the estimation, balance between leakage of radioactive cesium contaminated water though lake bed and geothermal inflow of radioactive cesium-free water in the volcano was taken into account. Consequently, the water seepage rate of the Yugama crater lake was calculated to be 8.1-9.3 L s-1.


Sujet(s)
Accident nucléaire de Fukushima , Contrôle des radiations , Polluants radioactifs de l'eau , Césium , Radio-isotopes du césium , Japon , Lacs , Eau
7.
Clin Case Rep ; 6(6): 1128-1131, 2018 Jun.
Article de Anglais | MEDLINE | ID: mdl-29881581

RÉSUMÉ

As labor may mask a symptom of the rupture of ovarian cyst and delivery is a risk factor of its rupture, the possibility of rupture of ovarian cyst should always be considered during delivery.

8.
Sci Total Environ ; 622-623: 1153-1164, 2018 May 01.
Article de Anglais | MEDLINE | ID: mdl-29890584

RÉSUMÉ

Understanding ecosystem dynamics of radionuclides is necessary to ensure effective management for food safety. The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident on March 11, 2011 released large amounts of radiocesium (134Cs and 137Cs) and contaminated the environment across eastern Japan. In this study, we aimed to elucidate the temporal dynamics of 137Cs in the aquatic ecosystem of Lake Onuma on Mt. Akagi. The effective ecological half-life (Teff) of 137Cs in fishes, western waterweed (Elodea nuttallii), seston (phytoplankton and zooplankton), and lake water was estimated using survey data of 137Cs concentration collected from 2011 to 2016, and single- and two-component decay function models (SDM and TDM, respectively). The decay processes of 137Cs concentrations in wakasagi (Hypomesus nipponensis), pale chub (Zacco platypus), phytoplankton, and total 137Cs concentrations of the water column (WC) in the lake were well suited by the TDMs. The Teff in the fast component of the TDMs in these samples ranged from 0.49 to 0.74years. The Teff in the slow component of the TDMs could converge towards the physical half-life of 137Cs. Nearly five and a half years after the FDNPP accident, we concluded that 137Cs concentrations approached a state of dynamic equilibrium between some aquatic organisms (wakasagi, pale chub, and phytoplankton) and the environment (lake water). However, the decay processes of 137Cs concentrations in Japanese dace (Tribolodon hakonensis), western waterweed, zooplankton, and particulate- and dissolved-forms in the WC were better predicted for the SDM. The total 137Cs concentrations in inflowing river and spring waters were one to two orders of magnitude lower than lake water under normal flow conditions. However, particulate 137Cs contamination level in the river water was high after heavy rains. Overall, 137Cs contamination levels have significantly decreased in Lake Onuma, but monitoring surveys should be continued for further understanding of the reduction processes.


Sujet(s)
Radio-isotopes du césium/analyse , Accident nucléaire de Fukushima , Contrôle des radiations , Polluants radioactifs de l'eau/analyse , Animaux , Organismes aquatiques , Écosystème , Poissons , Chaine alimentaire , Japon , Lacs/composition chimique , Zooplancton
9.
Paediatr Drugs ; 20(3): 291, 2018 06.
Article de Anglais | MEDLINE | ID: mdl-29637469

RÉSUMÉ

"Newborns, infants, or young children aged 24 months and under who have Down syndrome, and children ≤ 24 months of age without a current hs-CHD if they had experienced persistent respiratory symptoms or regular outpatient treatment due to a respiratory tract infection in previous RSV seasons were also eligible for the study."

10.
Paediatr Drugs ; 20(1): 97-104, 2018 Feb.
Article de Anglais | MEDLINE | ID: mdl-28895096

RÉSUMÉ

OBJECTIVE: The aim of this study was to assess the safety and effectiveness of palivizumab for the prevention of lower respiratory tract infection (LRI) caused by respiratory syncytial virus (RSV) in children with immunocompromised conditions or Down syndrome. METHODS: In this multicenter, post-marketing surveillance study (December 2013 to December 2015), children aged ≤24 months with immunocompromised conditions or Down syndrome (without hemodynamically significant congenital heart disease) receiving palivizumab immunoprophylaxis during two RSV seasons were observed until 30 days after the final palivizumab injection. Safety [adverse events (AEs), serious AEs (SAEs), adverse drug reactions (ADRs), serious ADRs (SADRs)] and effectiveness (frequency, incidence, and duration of hospitalization due to RSV infections) were assessed. RESULTS: Of 304 patients receiving palivizumab, 167 (54.9%) had immunocompromised conditions, and 138 (45.4%) had Down syndrome; 260 (85.5%) completed palivizumab immunoprophylaxis. The annual mean (±standard deviation) number of doses was 5.3 (±2.4) per season. Overall, 220 AEs occurred in 99 patients (32.6%), including 89 SAEs in 53 patients (17.4%). Of these, 33 AEs in 25 patients (8.22%) were considered ADRs, and 13 ADRs in 11 patients (3.62%) were considered SADRs. In four patients, five SADRs (nephroblastoma and asthma in the same patient, septic shock, device-related infection, and drug-induced liver injury) were previously unreported; however, none were considered drug-related. During the observation period, five RSV infections occurred and two patients required hospitalization. CONCLUSION: Palivizumab was generally safe and effective for the prevention of LRI caused by RSV in newborns, infants, and children with immunocompromised conditions or Down syndrome up to the age of 24 months.


Sujet(s)
Syndrome de Down/complications , Sujet immunodéprimé/effets des médicaments et des substances chimiques , Palivizumab/usage thérapeutique , Infections à virus respiratoire syncytial/traitement médicamenteux , Infections à virus respiratoire syncytial/prévention et contrôle , Enfant d'âge préscolaire , Humains , Japon , Palivizumab/administration et posologie , Palivizumab/pharmacologie , Études prospectives
11.
Rheumatol Ther ; 4(1): 151-166, 2017 Jun.
Article de Anglais | MEDLINE | ID: mdl-28364381

RÉSUMÉ

INTRODUCTION: The objective of this study was to evaluate the real-world safety and effectiveness of adalimumab with methotrexate (MTX) in disease-modifying antirheumatic drug (DMARD)- and biologic-naïve Japanese patients with rheumatoid arthritis (RA) at risk of progressive structural joint damage. METHODS: This multicenter, prospective, observational, postmarketing surveillance study was conducted between February 2013 and April 2015 at 84 centers in Japan. Patients with RA at risk of progressive structural joint damage were enrolled and initiated treatment with adalimumab and MTX. Adverse events were recorded up to week 28. Effectiveness/disease activity was assessed using the Disease Activity Score based on a 28-joint count with erythrocyte sedimentation rate and C-reactive protein (DAS28-4ESR and DAS28-4CRP), Clinical Disease Activity Index, and Simplified Disease Activity Index at 0, 4, 12, and 24 weeks. DAS28-4CRP response was evaluated in the low-dose (<8 mg/week) and high-dose (≥8 mg to ≤16 mg/week) MTX groups at week 24. RESULTS: One hundred fifty-seven of 163 patients comprised the safety cohort: mean (SD) age, 56.5 (13.9) years; females, 65.6%; rheumatoid factor positive, 73.2%; anti-cyclic citrullinated peptide antibody positive, 66.9%; bone erosions, 51.6%; mean disease duration, 9.5 months. The majority of patients (≥80%) had moderate or high disease activity at baseline, and ≥50% with available data achieved remission or low disease activity at week 24 (DAS28-4CRP <3.2). Five serious adverse drug reactions occurred in four patients, including pyelonephritis, Pneumocystis jiroveci pneumonia, interstitial lung disease, pleurisy, and pericarditis; the outcomes were either recovered or recovering. Significant improvements/reductions in disease activity over 24 weeks were noted in all effectiveness measures (P < 0.0001). Most of the population achieved DAS28-4CRP remission (<2.6) at week 24 regardless of the MTX dose. CONCLUSION: Adalimumab in combination with MTX could be a beneficial treatment option for DMARD- and biologic-naïve Japanese patients with RA at risk of progressive structural joint damage. FUNDING: AbbVie GK and Eisai. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT01783730.

12.
Gynecol Minim Invasive Ther ; 6(1): 6-11, 2017.
Article de Anglais | MEDLINE | ID: mdl-30254861

RÉSUMÉ

STUDY OBJECTIVE: In order to reduce the risk of vaginal recurrence, we have chosen total laparoscopic modified radical hysterectomy instead of extrafascial hysterectomy in the treatment of endometrial cancer. The aim of this study was to assess the safety of this method. DESIGN: Retrospective study of gynecological patients. SETTING: Yokohama City University Medical Center, Yokohama, Japan. PATIENTS: Forty-nine patients who underwent total laparoscopic modified radical hysterectomy for the treatment of endometrial cancer at our hospital between December 2011 and September 2015. INTERVENTIONS: Total laparoscopic modified radical hysterectomy + bilateral salpingo-oophorectomy (n = 20), total laparoscopic modified radical hysterectomy + bilateral salpingo-oophorectomy + pelvic lymphadenectomy (n = 18), or total laparoscopic modified radical hysterectomy + bilateral salpingo-oophorectomy + pelvic and para-aortic lymphadenectomy (n = 11). MEASUREMENTS AND MAIN RESULTS: The surgical outcomes were analyzed and compared to previous reports. The median operative time was 204 minutes (range, 99-504 minutes) and the median intraoperative blood loss was 150 mL (range, 0-680 mL). No patients needed a blood transfusion, conversion to laparotomy, or reoperation. Intra- and postoperative complications were observed in three patients and nine patients, respectively. The amount of blood loss and the incidence of complications in our study were almost identical to previous reports of laparoscopic hysterectomy. The operative time in our study was equivalent to previous reports of total laparoscopic modified radical hysterectomy. CONCLUSION: Total laparoscopic modified radical hysterectomy is safe and feasible for the treatment of early stage endometrial cancer. This procedure can be an alternative to total laparoscopic hysterectomy, especially when the uterus must be removed completely.

13.
Sci Total Environ ; 575: 1247-1254, 2017 Jan 01.
Article de Anglais | MEDLINE | ID: mdl-27707667

RÉSUMÉ

The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident has resulted in the contamination of the environment in Gunma Prefecture with radioisotope cesium (radio-Cs, 134Cs and 137Cs). Concentrations of radio-Cs >500Bqkg-1 were found in wakasagi (Hypomesus nipponensis) in Lake Onuma at the top of Mount (Mt.) Akagi in August 2011. To explain the mechanism of this contamination, monitoring studies have been conducted around Lake Onuma by measuring radio-Cs concentrations in samples of fish, aquatic plants, plankton, lake water, lake sediments, and surrounding soil. The leachability of radio-Cs was evaluated using sequential extraction by Tessier et al. The total concentration of radio-Cs in Lake Onuma ecosystems decreased gradually with time. In the brown forest soil, radio-Cs concentrations of 2000 to 6000Bqkg-1 were detected. The abundance ratio of the easy-elution form (exchangeable and carbonate forms) in the samples was <10%. The concentrations in phytoplankton samples were 3-6 times higher than those in wakasagi samples. The ratios of easy-elution forms increased by the rank in the food chain; 37% in phytoplankton, 78% in zooplankton, and 97% in wakasagi. It is likely that the lower ratio of the easy-elution form in phytoplankton is related to the adsorption of radio-Cs on suspended substances in the lake, as suggested by the analyses of aluminum and titanium in the phytoplankton, zooplankton, and wakasagi samples. The high concentrations of radio-Cs in wakasagi would be related also to the characteristics of closed mountain lakes.


Sujet(s)
Organismes aquatiques , Radio-isotopes du césium/analyse , Lacs/analyse , Contrôle des radiations , Polluants radioactifs du sol/analyse , Polluants radioactifs de l'eau/analyse , Animaux , Fractionnement chimique , Accident nucléaire de Fukushima , Sédiments géologiques/analyse , Japon , Sol/composition chimique
14.
Mol Clin Oncol ; 5(1): 113-116, 2016 Jul.
Article de Anglais | MEDLINE | ID: mdl-27330779

RÉSUMÉ

Ectopic adrenocorticotropic hormone (ACTH) is rarely secreted by neuroendocrine tumors. Although neuroendocrine tumors may occur at any site in the gastrointestinal system, they very rarely occur in the ampulla of Vater and have a poor prognosis. The present study described the first Cushing's syndrome as a result of ectopic ACTH arising from the ampulla of Vater neuroendocrine carcinoma. A 69-year-old female was admitted with clinical features of Cushing's syndrome, confirmed biochemically by hypokalemia, and elevated levels of ACTH and cortisol. In further investigations, a tumor of the ampulla of Vater and liver metastases were detected. Pathological analysis of the biopsy confirmed a neuroendocrine carcinoma, which was immunohistochemically positive for chromogranin A, synaptophysin, cluster of differentiation 56 and ACTH. Therefore, the present study diagnosed a functional and metastatic neuroendocrine carcinoma of the ampulla of Vater with ectopic ACTH production causing Cushing's syndrome. The patient succumbed to mortality 4 months later, despite administration of combined chemotherapy with irinotecan and cisplatin.

15.
Clin Exp Pharmacol Physiol ; 34(3): 238-43, 2007 Mar.
Article de Anglais | MEDLINE | ID: mdl-17250645

RÉSUMÉ

1. Recently, we reported that 4-hydroxyderricin, one of the major chalcones in Angelica keiskei extract (ethyl acetate extract from the yellow liquid of stems), exerted hypotensive and lipid regulatory actions in stroke-prone spontaneously hypertensive rats (SHRSP). In the present study, we isolated xanthoangelol, another major chalcone in A. keiskei extract, and examined the effect of dietary xanthoangelol on blood pressure and lipid metabolism in SHRSP. 2. Six-week-old male SHRSP were fed diets containing 0.02% or 0.1% xanthoangelol (0.02 and 0.10 Xan, respectively) for 7 weeks, with free access to the diet and water. There were no significant changes in daily food intake, bodyweight or systolic blood pressure throughout the experimental period. Serum total cholesterol levels tended to decrease in the two experimental groups (albeit not significantly), which was due to a dose-dependent decrease in the cholesterol content of the low-density lipoprotein (LDL) fraction. These results suggest that dietary xanthoangelol decreases serum LDL levels. 3. In the liver, significant dose-dependent decreases in relative liver liver weight and total triglyceride content were seen in the 0.02 and 0.10 Xan groups. In addition, a significant decrease in total cholesterol content was found in the 0.10 Xan group, which may be due to an elevation of faecal cholesterol excretion in addition to the decrease in liver weight. 4. Investigation of the hepatic mRNA expression of proteins involved in lipid metabolism indicated that there was a significant increase in peroxisome proliferator-activated receptor (PPAR) alpha mRNA expression associated with the tendency for increases in acyl-coenzyme A (CoA) synthetase and acyl-CoA oxidase mRNA expression in the 0.10 Xan group, which may be responsible, at least in part, for the decrease in hepatic triglyceride content in the xanthoangelol-treated rats. In addition, a significant increase in LDL receptor mRNA expression in the 0.10 Xan group may be responsible, at least in part, for the decrease in serum LDL levels in the xanthoangelol-treated rats. 5. In conclusion, dietary xanthoangelol results in a reduction of serum LDL levels and decreases in total cholesterol and triglyceride contents in the liver of SHRSP. These beneficial effects are more effective following consumption of diet containing 0.10% xanthoangelol.


Sujet(s)
Angelica/composition chimique , Chalcone/analogues et dérivés , Antienzymes/pharmacologie , Métabolisme lipidique/effets des médicaments et des substances chimiques , Animaux , Apolipoprotéines/analyse , Apolipoprotéines/métabolisme , Pression sanguine/effets des médicaments et des substances chimiques , Chalcone/pharmacologie , Régime alimentaire , Fèces/composition chimique , Glucose/analyse , Glucose/métabolisme , Lipides/analyse , Lipoprotéines/sang , Foie/métabolisme , Tiges de plante/composition chimique , Rats , Rats de lignée SHR , Accident vasculaire cérébral/génétique
16.
Ind Health ; 41(3): 273-8, 2003 Jul.
Article de Anglais | MEDLINE | ID: mdl-12916759

RÉSUMÉ

To assess the exposure of welders to thorium-232 (232Th) during tungsten inert gas arc (TIG) welding, airborne concentrations of 232Th in the breathing zone of the welder and background levels were measured. The radioactive concentrations were 1.11 x 10(-2) Bq/m3 during TIG welding of aluminum (TIG/Al), 1.78 x 10(-4) Bq/m3 during TIG welding of stainless steel (TIG/SS), and 1.93 x 10(-1) Bq/m3 during electrode sharpening, with 5.82 x 10(-5) Bq/m3 background concentration. Although the annual intake of 232Th estimated using these values did not exceed the annual limit intake (ALI, 1.6 x 10(2) Bq), we recommend reducing 232Th exposure by substituting thoriated electrodes with a thorium-free electrodes, setting up local ventilation systems, and by using respiratory protective equipment. It is also necessary to inform workers that thoriated tungsten electrodes contain radioactive material.


Sujet(s)
Polluants atmosphériques d'origine professionnelle/effets indésirables , Électrodes , Exposition professionnelle/analyse , Thorium/effets indésirables , Tungstène , Soudage/méthodes , Humains , Japon , Analyse par activation neutronique , Exposition professionnelle/effets indésirables
17.
Anal Sci ; 19(8): 1215-7, 2003 Aug.
Article de Anglais | MEDLINE | ID: mdl-12945682

RÉSUMÉ

Multielements in a typical Japanese diet certified reference material prepared at the National Institute for Environmental Studies (NIES) of Japan, in collaboration with the National Institute of Radiological Sciences (NIRS) of Japan were determined by instrumental neutron activation analysis (INAA). Five samples (ca. 510-1000 mg) and comparative standards were irradiated for a short time (10 s) at a thermal neutron flux of 1.5 x 10(12) n cm(-2) s(-1) (pneumatic transfer) and for a long time (6 h) at a thermal neutron flux of 3.7 x 10(12) n cm(-2) s(-1) (central thimble) in the Rikkyo University Research Reactor (TRIGA Mark-II, 100 kW). The irradiated samples were measured by conventional gama-ray spectrometry using a coaxial Ge detector, and by anti-coincidence and coincidence gamma-ray spectrometry with a coaxial Ge detector and a well-type NaI(Tl) detector. The concentrations of 38 elements were determined by these methods.

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