Nagasaki sediments reveal that long-term fate of plutonium is controlled by select organic matter moieties.

Forecasting the long-term fate of plutonium (Pu) is becoming increasingly important as more worldwide military and nuclear-power waste is being generated. Nagasaki sediments containing bomb-derived Pu that was deposited in 1945 provided a unique opportunity to explore the long-term geochemical behavior of Pu. Through a combination of selective extractions and molecular characterization via electrospray ionization Fourier-transform ion cyclotron resonance mass spectrometry (ESI-FTICRMS), we determined that 55 ±â€¯3% of the bomb-derived 239,240Pu was preferentially associated with more persistent organic matter compounds in Nagasaki sediments, particularly those natural organic matter (NOM) stabilized by Fe oxides (NOMFe-oxide). Other organic matter compounds served as a secondary sink of these bomb-derived 239,240Pu (31 ±â€¯2% on average), and <20% of the 239,240Pu was immobilized by inorganic mineral particles. In a narrow, 239,240Pu-enriched layer of only 9-cm depth (total core depth was 600 cm), N-containing carboxyl aliphatic and/or alicyclic molecules (CCAM) in NOMFe-oxide and other NOM fractions immobilized the majority of 239,240Pu. Among the cluster of N-containing CCAM moieties, hydroxamate siderophores, the strongest known Pu chelators in nature, were further detected in these "aged" Nagasaki bomb residue-containing sediments. While present long-term disposal and environmental remediation modeling assume that solubility limits and sorption to mineral surfaces control Pu subsurface mobility, our observations suggest that NOM, which is present in essentially all subsurface systems, undoubtedly plays an important role in sequestrering Pu. Ignoring the role of NOM in controlling Pu fate and transport is not justified in most environmental systems.

Two-step extraction method for lead isotope fractionation to reveal anthropogenic lead pollution.

This study developed the 2-step extraction method which eluted the Pb adsorbing on the surface of sediments in the first solution by aqua regia and extracted the Pb absorbed inside particles into the second solution by mixed acid of nitric acid, hydrofluoric acid and hydrogen peroxide solution. We applied the method to sediments in the enclosed water area and found out that the isotope ratios of Pb in the second solution represented those of natural origin. This advantage of the method makes it possible to distinguish the Pb between natural origin and anthropogenic source on the basis of the isotope ratios. The results showed that the method was useful to discuss the Pb sources and that anthropogenic Pb in the sediment samples analysed was mainly derived from China because of transboundary air pollution.

Spatiotemporal distribution and fluctuation of radiocesium in Tokyo Bay in the five years following the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident.

A monitoring survey was conducted from August 2011 to July 2016 of the spatiotemporal distribution in the 400 km2 area of the northern part of Tokyo Bay and in rivers flowing into it of radiocesium released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. The average inventory in the river mouth (10 km2) was 131 kBq⋅m-2 and 0.73 kBq⋅m-2 in the central bay (330 km2) as the decay corrected value on March 16, 2011. Most of the radiocesium that flowed into Tokyo Bay originated in the northeastern section of the Tokyo metropolitan area, where the highest precipitation zone of 137Cs in soil was almost the same level as that in Fukushima City, then flowed into and was deposited in the Old-Edogawa River estuary, deep in Tokyo Bay. The highest precipitation of radiocesium measured in the high contaminated zone was 460 kBq⋅m-2. The inventory in sediment off the estuary of Old-Edogawa was 20.1 kBq⋅m-2 in August 2011 immediately after the accident, but it increased to 104 kBq⋅m-2 in July 2016. However, the radiocesium diffused minimally in sediments in the central area of Tokyo Bay in the five years following the FDNPP accident. The flux of radiocesium off the estuary decreased slightly immediately after the accident and conformed almost exactly to the values predicted based on its radioactive decay. Contrarily, the inventory of radiocesium in the sediment has increased. It was estimated that of the 8.33 TBq precipitated from the atmosphere in the catchment regions of the rivers Edogawa and Old-Edogawa, 1.31 TBq migrated through rivers and was deposited in the sediments of the Old-Edogawa estuary by July 2016. Currently, 0.25 TBq⋅yr-1 of radiocesium continues to flow into the deep parts of Tokyo Bay.

Radioactive contamination in the Tokyo metropolitan area in the early stage of the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident and its fluctuation over five years.

Radioactive contamination in the Tokyo metropolitan area in the immediate aftermath of the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident was analyzed via surface soil sampled during a two-month period after the accident. 131I, 134Cs, and 137Cs were detected in these soil samples. The activity and inventory of radioactive material in the eastern part of Tokyo tended to be high. The 134Cs/137Cs activity ratio in soil was 0.978 ± 0.053. The 131I/137Cs ratio fluctuated widely, and was 19.7 ± 9.0 (weighted average 18.71 ± 0.13, n = 14) in the Tokyo metropolitan area. The radioactive plume with high 131I activity spread into the Tokyo metropolitan area and was higher than the weighted average of 6.07 ± 0.04 (n = 26) in other areas. The radiocesium activity and inventory surveyed in soil from a garden in Chiyoda Ward in the center of Tokyo, fell approximately 85% in the four months after the accident, and subsequently tended to rise slightly while fluctuating widely. It is possible that migration and redistribution of radiocesium occurred. The behavior of radiocesium in Tokyo was analyzed via monitoring of radiocesium in sludge incineration ash. The radiocesium activity in the incineration ash was high at wastewater treatment centers that had catchment areas in eastern Tokyo and low at those with catchment areas in western Tokyo. Similar to the case of the garden soil, even in incineration ash, the radiocesium activity dropped rapidly immediately after the accident. The radiocesium activity in the incineration ash fell steadily from the tenth month after the accident until December 2016, and its half-life was about 500 days. According to frequency analysis, in central Tokyo, the cycles of fluctuation of radiocesium activity in incineration ash and rainfall conformed, clearly showing that radiocesium deposited in urban areas was resuspended and transported by rainfall run-off.

Concentration of antifouling biocides and metals in sediment core samples in the northern part of Hiroshima Bay.

Accumulation of Ot alternative antifoulants in sediment is the focus of this research. Much research had been done on surface sediment, but in this report, the accumulation in the sediment core was studied. The Ot alternative antifoulants, Diuron, Sea-Nine211, and Irgarol 1051, and the latter's degradation product, M1, were investigated in five samples from the northern part of Hiroshima Bay. Ot compounds (tributyltin (TBT) and triphenyltin (TPT)) were also investigated for comparison. In addition, metal (Pb, Cu, Zn, Fe and Mn) levels and chronology were measured to better understand what happens after accumulation on the sea floor. It was discovered that Ot alternative antifoulant accumulation characteristics in sediment were like Ot compounds, with the concentration in the sediment core being much higher than surface sediment. The concentration in sediment seems to have been affected by the regulation of Ot compounds in 1990, due to the concentration of Ot alternative antifoulants and Ot compounds at the survey point in front of the dock, showing an increase from almost the same layer after the regulation.

Direct absorption of methyl mercury by lymph.

Methyl mercury is contained in fish and seafood products and is taken up into the body in food. While the central nervous system is known as a target organ, methyl mercury also induces autoimmunity and acts as a potent immunosuppressor. The aim of the present study is to know whether methyl mercury is directly absorbed by lymph. Conscious rats were infused with methyl mercury (4 mg/kg) via duodenal tubing as a single pulse infusion, followed by the continuous infusion of saline, and lymphatic fluids were continuously collected from the thoracic lymph duct every 30 min until 360 min after infusion. Mercury was detected immediately after infusion, and total mercury contents in lymph gradually increased until 90-120 min, remained steady, and then gradually decreased until 360 min; however, the amount of mercury collected during 330-360 min was about twofold higher than during 0-30 min. The amount of cumulative mercury in lymph at 360 min was 1.4 µg. In contrast, blood mercury concentration was 2.4 µg/ml 5 min after infusion, with the value at 360 min being 12.6 times higher than at 5 min. Plasma mercury concentration was 56 ng/ml at 5 min, with hundreds of nanograms per milliliter of mercury detected until 360 min. From the present study, it is concluded that some methyl mercury is directly absorbed by lymph and remains steady 6 h after infusion.

Improved detection of gastric cancer during screening by additional radiographs as judged necessary by the radiographer.

PURPOSE: The aim of this study was to determine whether additional radiographs, as judged necessary by the radiographer, improves cancer detection during gastric cancer screening. MATERIALS AND METHODS: We analyzed 144 gastric cancer cases among 137 744 individuals who underwent X-ray screening for gastric cancer. Radiographs were obtained by 17 radiographers at a screening center in Japan from April 2004 to March 2008. Additional radiographs were taken based on the radiographer's judgment in cases of suspected cancer. During double-blind reinterpretation of the cancer case radiographs by two radiologists, we determined the number of cancer cases that were detected by standard radiographs alone. We next determined the number of cancer cases detected using both standard radiographs and additional radiographs. RESULTS: Compared to the number of cancer cases detected with standard radiographs alone (120 cases detected, 24 cases undetected), the number of cancer cases detected with both standard and additional radiographs (137 cases detected, 7 cases undetected) significantly increased (17 cases; P < 0.001, McNemar test). CONCLUSION: We found that taking additional radiographs, when judged necessary by the radiographer during radiographic gastric cancer screening, improves cancer detection.

Diagnostic validity of high-density barium sulfate in gastric cancer screening: follow-up of screenees by record linkage with the Osaka Cancer Registry.

BACKGROUND: The use of high-density barium sulfate was recommended by the Japan Society of Gastroenterological Cancer Screening (JSGCS) in 2004. We evaluated the diagnostic validity of gastric cancer screening that used high-density barium sulfate. METHODS: The study subjects were 171 833 residents of Osaka, Japan who underwent gastric cancer screening tests at the Osaka Cancer Prevention and Detection Center during the period from 1 January 2000 through 31 December 2001. Screening was conducted using either high-density barium sulfate (n = 48 336) or moderate-density barium sulfate (n = 123 497). The subjects were followed up and their medical records were linked to those of the Osaka Cancer Registry through 31 December 2002. The results of follow-up during 1 year were defined as the gold standard, and test performance values were calculated. RESULTS: The sensitivity and specificity of the screening test using moderate-density barium sulfate were 92.3% and 91.0%, respectively, while the sensitivity and specificity of the high-density barium test were 91.8% and 91.4%, respectively. The results of area under receiver-operating-characteristic (ROC) curve analysis revealed no significant difference between the 2 screening tests. CONCLUSIONS: Screening tests using high- and moderate-density barium sulfate had similar validity, as determined by sensitivity, specificity, and ROC curve analysis.

Induction of metallothionein in mouse cerebellum and cerebrum with low-dose thimerosal injection.

Thimerosal, an ethyl mercury compound, is used worldwide as a vaccine preservative. We previously observed that the mercury concentration in mouse brains did not increase with the clinical dose of thimerosal injection, but the concentration increased in the brain after the injection of thimerosal with lipopolysaccharide, even if a low dose of thimerosal was administered. Thimerosal may penetrate the brain, but is undetectable when a clinical dose of thimerosal is injected; therefore, the induction of metallothionein (MT) messenger RNA (mRNA) and protein was observed in the cerebellum and cerebrum of mice after thimerosal injection, as MT is an inducible protein. MT-1 mRNA was expressed at 6 and 9 h in both the cerebrum and cerebellum, but MT-1 mRNA expression in the cerebellum was three times higher than that in the cerebrum after the injection of 12 microg/kg thimerosal. MT-2 mRNA was not expressed until 24 h in both organs. MT-3 mRNA was expressed in the cerebellum from 6 to 15 h after the injection, but not in the cerebrum until 24 h. MT-1 and MT-3 mRNAs were expressed in the cerebellum in a dose-dependent manner. Furthermore, MT-1 protein was detected from 6 to 72 h in the cerebellum after 12 microg/kg of thimerosal was injected and peaked at 10 h. MT-2 was detected in the cerebellum only at 10 h. In the cerebrum, little MT-1 protein was detected at 10 and 24 h, and there were no peaks of MT-2 protein in the cerebrum. In conclusion, MT-1 and MT-3 mRNAs but not MT-2 mRNA are easily expressed in the cerebellum rather than in the cerebrum by the injection of low-dose thimerosal. It is thought that the cerebellum is a sensitive organ against thimerosal. As a result of the present findings, in combination with the brain pathology observed in patients diagnosed with autism, the present study helps to support the possible biological plausibility for how low-dose exposure to mercury from thimerosal-containing vaccines may be associated with autism.

Validity and reliability of the community-environmental index regarding daily living among the mental disorders in community: an assessment instrument based on community nursing activity.

The purpose of this study was to examine validity and reliability of a community-environmental assessment instrument analysing community-environmental conditions among the mental disorders in a community. Thirty-three factors were extracted from the data based on a nationwide investigation by the factor analysis. The principal component analysis was applied to these extracted factors, and the first principal component score (1PCS) was interpreted as a synthetic index regarding daily living of the mental disorders in the community. Then, validity and reliability of 1PCS were confirmed. The item analyses from a viewpoint of statistics processing were adopted. As a result, coefficient alpha of the reliability was calculated from the scores and variances, and its value was 0.96. Next, kappa statistic was calculated in order to confirm whether two indices derived from the 52-item and 33-item questionnaires had the correspondence of the actual conditions with 1PCS in regard to the population scale of the municipality. As a result, the kappa was 0.94. In this study, we proposed the 33-item questionnaire composed of 33 factors. This was called as the Morita's community-environmental index (MCEI). It was suggested that the MCEI was useful to assess community-environmental conditions regarding daily living of the mental disorders in the community.

Film-reading ability of radiographers in detecting gastric cancer during screening using X-ray examination.

PURPOSE: The aim of this study was to evaluate the film-reading ability of radiographers in detecting gastric cancer during screening X-ray examinations. MATERIALS AND METHODS: A test set of 100 patients (50 negative and 50 positive; mean age 62 years, range 33-78 years) given a stomach X-ray examination were selected from those who underwent gastric cancer screening in Osaka, Japan, between 2000 and 2003. Eleven radiographers and four radiologists scored the test set on a five-point scale. A receiver operating characteristic (ROC) analysis was performed, and the area under the ROC curve (AUC) was defined as a measure of film-reading ability to detect cancer. RESULTS: No significant difference (two-tailed P = 0.962, Welch's t-test) was observed between averaged AUC values from radiographers (0.76, range 0.85-0.62) and radiologists (0.75, range 0.86-0.62). CONCLUSION: Film-reading ability of radiographers in detecting gastric cancer during screening X-ray examinations was not significantly different from that of radiologists. Our results suggest that radiographers can assist radiologists to detect gastric cancer during screening.

Expression of metallothionein mRNAs on mouse cerebellum microglia cells by thimerosal and its metabolites.

Effects of thimerosal and its metabolites, ethyl mercury and thiosalicylate, on the expression of metallothionein (MT) mRNAs in mouse cerebellum microglia cell line, C8-B4 cells, were studied. The level of MT-1 mRNA significantly decreased at early hours and recovered time-dependently 24h after thimerosal was added to the C8-B4 cells. However, MT-2 and MT-3 mRNA expressions did not change from the control group. In contrast, the expression of MT-1 mRNA increased in a mouse neuroblastoma cell line 6h after incubation with thimerosal. In addition, the level of MT-1 mRNA decreased in C8-B4 cells 6h after the addition of thiosalicylate, but ethyl mercury induced MT-1 mRNA expression. When cell viability was compared with thimerosal, thiosalicylate, and ethyl mercury, the viability of C8-B4 cells decreased dose-dependently 24h after either thimerosal or ethyl mercury was added; however, the viability increased dose-dependently until 15 microM thiosalicylate was added. From the present results, it is concluded that the expression of MT-1 mRNA may be mediated by different factors than the expression of MT-2 mRNA in C8-B4 cells. The reduction of MT-1 mRNA level by thiosalicylate may affect the proliferation of C8-B4 cells.

The Japanese guidelines for gastric cancer screening.

BACKGROUND: Gastric cancer is the leading cause of death from cancer in Japan. In 2004, there were 50 562 deaths from gastric cancer; they accounted for 15.8% of the total number of cancer deaths. Since 1983, under the Health Service Law for the Aged, gastric cancer screening has been conducted nationwide for all residents aged 40 years and over. METHODS: On the basis of the standardized method developed for the Japanese Guidelines for Cancer Screening, the efficacies of various methods for gastric cancer screening were evaluated and the guideline was developed. RESULTS: Four methods for gastric cancer screening were evaluated: photofluorography, endoscopy, serum pepsinogen testing and Helicobacter pylori antibody testing. On the basis of the analytic framework involving key questions, 1715 articles, published from January 1985 to February 2005, were selected using MEDLINE, the Japanese Medical Research Database and other methods. After the systematic literature review, 10 articles were identified as direct evidence and 49 articles as indirect evidence. The studies that evaluated mortality reduction from gastric cancer included five case-control and two cohort studies for radiographic screening. On the basis of the balance of benefits and harms, the recommendations for population-based and opportunistic screening were formulated. Gastric cancer screening using photofluorography was recommended for both screening programs. The other methods were not recommended for population-based screening due to insufficient evidence. CONCLUSIONS: The guideline for gastric cancer screening guideline was developed based on the previously established method. Gastric cancer screening using photofluorography is recommended for population-based and opportunistic screening in Japan.

Postural stability and physical performance in social dancers.

This cross-sectional study examined the benefits of social dancing on postural stability and physical performance in dancers aged 50 years or more. Walking speed, lower limb reaction time and low back flexibility were measured in 202 social dancers and 202 community-dwelling comparison subjects aged 50-87 years. The results showed that dancers who were older than 60 years had better postural stability and faster leg reaction times, whilst dancers aged 50-59 showed only better flexibility, when compared with the controls. Male dancers had greater low back flexibility and leg reaction time compared to controls. In contrast, female dancers had superior performance only for leg reaction time when compared with controls. The results indicate that social dancing is associated with enhanced postural stability and physical performance in older adults.

Effects of lipopolysaccharide and chelator on mercury content in the cerebrum of thimerosal-administered mice.

Thimerosal is one of the best-known preservative agents for vaccines in the world but a relationship between its use and autism has long been suspected so that its effects on the brain need more detailed research. We here examined the influence of lipopolysaccharide injury to the blood-brain barrier on the penetration of mercury from thimerosal into mouse cerebrums, as well as the effect of chelator of heavy metals on cerebrum mercury content. Mercury can be expected to be detected in the cerebrum of normal mice, because the metal is present in standard mouse chow. When 60µg/kg of thimerosal was subcutaneously injected into the mouse, the mercury content in the cerebrum was significantly higher 48h after the thimerosal injection with a maximum peak after 72h. In addition, mercury content in the cerebrum was still higher on day 7 than in the control group. When lipopolysaccharide was pre-injected into mice to induce damage on blood-brain barrier, the mercury content in the cerebrum was significantly higher at 24 and 72h after the injection of 12µg/kg of thimerosal compared to the control group, this dose alone does not cause any increase. The mercury content in the cerebrums of mice was decreased to the control group level on day 7 when a chelator, dimercaprol, was administered once a day from days 3 to 6 after a 60µg/kg, s.c. injection. In addition, d-penicillamine as a chelator decreased the mercury contents in the cerebrum after the high dose administration. In conclusion, a physiological dose of thimerosal did not increase the content of mercury in the cerebrum, but levels were increased when damage to the blood-brain barrier occurred in mice injected with thimerosal. In addition, a chelator of heavy metals may be useful to remove mercury from the cerebrum.

Intra-individual variation in the vocalized frequency of the Taiwanese leaf-nosed bat, Hipposideros terasensis, influenced by conspecific colony members.

We examined the intra-individual variation in resting frequency of the constant-frequency component of the second harmonic of the pulse (F (rest)) over 4 years in a laboratory colony of the Taiwanese leaf-nosed bat (Hipposideros terasensis). Patterns of change in F (rest) were observed when individuals were added to or removed from the colony so that we investigated whether F (rest) was affected by neighboring colony members. F (rest) of each bat continually showed a long-term gradual change throughout the year, and all bats in the colony increased or decreased their F (rest) in the same direction as a group non-seasonally. The greatest short-term changes were observed when new bats with a relatively low F (rest) joined the colony and F (rest) of new bats converged with those of the original colony members around 8 -16 days after their introduction. Conversely, a single individual showed sudden short-term decrease in F (rest) after its isolation from other colony members. These findings strongly indicate that F (rest) is flexible according to the presence of neighboring conspecific bats. We suggest that the audio-vocal feedback for conspecific pulses appears to be involved in the short- or long-term intra-individual variation in F (rest) other than factors previously thought such as age or season.

Multidimensional structures of comprehensive accessibility of community support for people with mental disorders in Japan: a nationwide investigation.

The purpose of this study was to define the concept of comprehensive accessibility of community support for people with mental disorders and to clarify the multidimensional structures of comprehensive accessibility. We developed a self-administered questionnaire consisting of 47 items. A complete list of the municipalities in Japan was prepared, and the questionnaire was mailed to 3310 municipalities. Principal component analyses were applied to valid data in order to analyse the index and multidimensional structures of comprehensive accessibility. As a result, 14 principal components of community support for people with mental disorders were extracted. These principal components were interpreted as the scales for the evaluation of comprehensive accessibility. The two first principal component scores were interpreted as the index indicating the level of comprehensive accessibility. The other 12 principal components were interpreted as the scales constituting the multidimensional space of comprehensive accessibility.

The effects of Tai Chi Chuan on physiological function and fear of falling in the less robust elderly: an intervention study for preventing falls.

The aim of this report is to investigate the effects of 8 weeks of intensive Tai Chi Chuan (TCC) training on physiological function and fear of falling (FOF) in the less-robust elderly. Forty-nine community-dwelling elderly, aged 60 or older, were classified randomly into a TCC training or control group. Physical performance measures (including one-leg stance, trunk flexion, and walking speed) and interviews were conducted before and after the intervention. The TCC group showed significant improvements in balance and flexibility, and a reduced FOF, when compared with the control group after the intervention. However, walking speed did not change significantly. The results suggest that a high-frequency, short-term TCC training program can improve balance, flexibility, and increase the confidence of less-robust elderly. These suggest the effectiveness of TCC for intervention as a means to prevent falling among high-risk elderly populations.

Nationwide study of environmental assessment for people with schizophrenia in Japan.

The purpose of the present study was to develop an environmental assessment tool related to the living of the mentally disabled and to examine the health care professionals' perception of the current situations and its importance. The relationships between the current and ideal environmental situations were analyzed. The survey was conducted at 3310 municipalities nationwide by mailing self-report questionnaires, which consisted of 52 items developed by specialists for the mentally disabled and their families. The 52-item questionnaire was rated with a five-point scale for both current and important environmental situations. The main findings included statistically significant differences between the mean scores of the current and important environmental situations, items perceived as important at a similar degree, and those suggesting the largest gap between the current and important situations related to learning opportunities. These results could be useful for implementation in community health nursing.

Is a Type A behavior pattern associated with falling among the community-dwelling elderly?

The aim of this report is to investigate the relationship between Type A behavior patterns and the likelihood of falling among community-dwelling elderly, and to compare differences in the prevalence, reasons, locations, injuries and frequency of falls between Type A and non-Type A personalities. Persons aged 60 or older living in 3 communities of Nanjing, China participated in a baseline survey conducted in 2000 (n=879), and falling incidents were followed for 1 year. The survey employed a self-administered questionnaire designed to elicit demographic data, current health problems and medications taken, intake of alcohol, exercise habits, physical function, environmental hazards and Type A behavior patterns. Several factors associated with falling such as health condition, physical function and environmental factors did not differ between the Type A and non-Type A groups except in the male tendency toward heart disease and their inability to walk fast. The results of logistic regression analyses showed that a Type A behavior pattern was independently associated with falling in males but not in females. Findings in the present study suggest that a Type A behavior pattern might play an important role in the rate of falling incidents in elderly males, since some characteristics of this personality pattern might lead to risk-taking behavior. More studies are needed to evaluate the association of certain behavior patterns with falling incidents.