Enhancement of Mass Interception Coefficient Data of Radiostrontium by Leafy Crops Using Global Fallout 90Sr and Naturally Occurring 7Be.

When artificial radionuclides are released into the atmospheric environment, one of the important processes by which they affect the human radiation dose is the direct deposition of the radionuclides onto crop surfaces. Because leafy vegetables are consumed while fresh and often raw, the mass interception coefficient [= concentration in food (Bq/kg dry mass (DM) or fresh mass)/total deposition (Bq/m2)] is a key parameter for estimating radionuclide concentrations in crops after the deposition of radionuclides on plant stands. However, such data are still sparse, especially for radiostrontium (89Sr and 90Sr). To enhance the mass interception coefficient data for leafy crops, we used global fallout 90Sr data in leafy crops harvested in 1963-1965 and the deposition data for the corresponding crop growing period. Geometric mean values of the mass interception coefficient of 90Sr for leafy crops were 2.8 m2 kg-1 DM for spinach, 0.60 m2 kg-1 DM for cabbage, and 1.3 m2 kg-1 DM for Chinese cabbage. For comparison, we measured naturally occurring 7Be in giant butterbur leaves, and the results showed that the data were similar to those of 90Sr for spinach. These data were similar to the previously obtained data by single spike radiotracer experiments. Therefore, in the case of nuclear emergency situations, mass interception coefficient data obtained using global fallout 90Sr and/or naturally occurring 7Be should be valuable to estimate radioactivity contamination levels of radiostrontium directly deposited on leafy crops.

Cesium-137 and 137Cs/133Cs atom ratios in marine zooplankton off the east coast of Japan during 2012-2020 following the Fukushima Dai-ichi nuclear power plant accident.

We measured the concentrations of cesium isotopes (133Cs, 134Cs, and 137Cs) in zooplankton samples collected in waters off the east coast of Japan from May 2015 to June 2020. By combining these data with those obtained previously from May 2012 to February 2015, we evaluated the long-term impacts of the Fukushima Dai-ichi Nuclear Power Plant accident on marine zooplankton. Relatively high 137Cs concentrations in zooplankton, exceeding 10 Bq/kg-dry weight, were sporadically observed until June 2016, regardless of year or station. After May-June 2017, 137Cs concentrations decreased to below 1 Bq/kg-dry at most stations, and by May 2020, concentrations were below 0.5 Bq/kg-dry except those off Fukushima Prefecture. Since the accident, the 137Cs/133Cs atom ratios of zooplankton samples were higher than those of ambient seawater until 2019, but in May-June 2020 the ratios matched those of seawater except off Fukushima Prefecture. Highly radioactive particles were not detected in zooplankton samples by autoradiography using imaging plates after May-June 2017, although they were before. Therefore, the persistence of elevated 137Cs/133Cs ratios in zooplankton relative to seawater for nine years after the accident was probably due to the incorporation of highly radioactive particles (cesium-bearing particles or clay-mineral aggregates with highly adsorbed radiocesium) onto/into zooplankton for several years after the accident. However, since at least May-June 2017, these elevated ratios have likely been caused by small highly radioactive particles (or larger particles disaggregated into small pieces) entering the ocean from land via rivers or directly discharged from the Fukushima Nuclear Power Plant. Microplastics enriched with radiocesium with higher 137Cs/133Cs ratios than seawater may have also contributed 137Cs to the zooplankton.

Increase in the left hippocampal dentate gyrus head volume after a 4-week bright light exposure in healthy participants: A randomized controlled study.

INTRODUCTION: Bright light therapy (BLT) has been used for treating seasonal affective disorder, depression and bipolar depression. However, it's precise mechanism remains unclear. Bright light exposure (BL) induces neurogenesis in the adult rat hippocampal dentate gyrus (DG). We hypothesized that BL may induce neurogenesis in the human DG as well. METHOD: A 4-week randomized controlled trial study was conducted, where healthy participants were randomly assigned to a BL group (10,000 lux) or dim light exposure group (DL group; 50 lux). Magnetic resonance imaging was performed at baseline and after 4 weeks. Longitudinal hippocampal subfield segmentation was generated via the FreeSurfer 7.1.1 hippocampal subfields module to evaluate volume of bilateral granule cell and molecular layer of the DG-head and -body. RESULTS: Our final sample size was 20, which consisted of BL group (n = 10) and DL group (n = 10). After age and sex adjustment, significant effects of time and group were detected in the left DG-head volume (p = 0.04). In the BL group, the left DG-head volume significantly increased (p = 0.004), whereas no significant volumetric change was observed in the DL group. CONCLUSIONS: This study revealed that 4-week BL significantly increased left DG-head volume in healthy participants. Thus, neurogenesis might be induced by BL in the human DG, which is a completely new mechanism of BLT.

The Present State of Lithium for the Prevention of Dementia Related to Alzheimer's Dementia in Clinical and Epidemiological Studies: A Critical Review.

Despite the unavailability of essential anti-dementia drugs, lithium may inhibit glycogen synthase kinase-3 (GSK-3) and decrease beta-amyloid and hyper-phosphorylated tau. In this review, we hypothesized that trace to standard levels of lithium (i.e., corresponding to the therapeutic levels for bipolar disorder) may be effective for dementia prevention. Excluding three insufficient level studies, we obtained two and one excellent clinical studies on standard and trace lithium levels, respectively, all of which supported the effects of lithium for dementia prevention. In addition, we identified good clinical and epidemiological studies (four each) on standard lithium levels, of which six studies supported the effects of lithium. Moreover, of three good epidemiological studies on trace lithium levels, two supported the aforementioned effects of lithium. The number of studies were substantially small, particularly those on trace lithium levels. Moreover, studies on standard lithium levels were insufficient to establish the efficacy of lithium for dementia prevention. This necessitates accumulating good or excellent clinical evidence for the effects of trace to standard lithium levels on dementia prevention.

Thought Process Evolved From Rigid to Flexible in a Patient With Bipolar Disorder Via "Return to Work Program": A Case Report.

ABSTRACT: In the working population, bipolar disorder can have a significant negative effect on professional relationships, attendance, functioning, and loss of productivity. In Japan, workers who take a leave due to depressive episodes receive a work-focused intervention program called the "return to work program" during their leave. A 39-year-old Japanese woman with bipolar II disorder took a third sick leave of absence. We recommended her the return to work program of our university hospital. At the beginning of the program, she had a rigid thought process toward her perceptions of her duties in the workplace and at home. Through the program, mindfulness might identify rigidity, group cognitive-behavioral therapy might correct rigidity, and self-analysis might have regained flexibility. In conclusion, a variety of effects of our return to work program might have enabled her thought process to evolve from rigid to flexible, and she showed successful reinstatement.

Inequality in the distribution of 137Cs contamination within freshwater fish bodies and its affecting factors.

Contamination of freshwater fishes with 137Cs remains as a serious problem in Japan, nearly 10 years after the Fukushima nuclear power plant accident, but there is limited information on the distribution of 137Cs contamination in fish bodies. The 137Cs distribution can be used for the estimation of internal radiation exposure through the consumption of fish and for the dose estimation of fish themselves. In this study, the 137Cs distribution in the bodies of 8 freshwater fish species was investigated as percentages of total body burden for fish inhabiting Lake Inba. Fish samples were caught in stake nets placed close to the shore approximately once a month. After the measurement of body length and fresh weight, the radioactivities of 137Cs in muscle, internal organs, spawn, milt and bone were assayed using high-purity germanium detectors. Analysis of all fish samples showed that the 137Cs distribution was highest in muscle (54 ± 12%), followed by internal organs (7.8 ± 4.6%), spawn (7.4 ± 5.4%), milt (3.2 ± 2.1%) and bone (1.2 ± 0.58%). Among fish species, the highest proportion of 137Cs in muscle was detected in largemouth bass (71 ± 1 3%), followed by snakehead (69 ± 14%), channel catfish (63 ± 17%), common carp (62 ± 14%), barbel steed (58 ± 6.5%), silver carp (57 ± 7.7%), bluegill (53 ± 4.7%), and crucian carp (50 ± 10%). These results suggested that the 137Cs in muscle was likely to be high in piscivorous fishes compared to omnivorous fishes, especially crucian carp. The proportion of 137Cs in muscle of crucian carp was not explained either by body length or fresh weight. However, a positive correlation was found between the proportion of 137Cs in muscle and the condition factor which was an indicator of nutritional status calculated from a length-weight relationship. This correlation implied that more 137Cs accumulated in muscle tissue of a fish species with high nutritional status. This is the first study to show that condition factor is more important than body length and wet weight in explaining the high proportion of 137Cs in muscle tissues, at least for crucian carp.

Maternal overprotection predicts consistent improvement of self-compassion during mindfulness-based intervention and existential approach: a secondary analysis of the EXMIND study.

BACKGROUND: Recently, we showed that 4-week mindfulness-based intervention (MBI) followed by 4-week existential approach (EXMIND) was as effective for developing self-compassion as 8-week MBI. This study aims to identify the predictors to EXMIND. METHODS: Of the 63 participants who completed the EXMIND group, 60 participants had baseline, 4-week, and 8-week total scores of the Self-Compassion Scale (SCS). Of the participants, 49 were female and 11 were male, with a mean age of 48.4 years. We investigated the participants' intervention response patterns, then used analysis of variance to compared those patterns by age, gender, and the baseline scores of the Temperament Evaluation of Memphis, Pisa and San Diego Auto-questionnaire, the Temperament and Character Inventory, Mini-Mental State Examination, the Japanese Adult Reading Test, Young Mania Rating Scale, Hamilton Rating Scale for Depression, the Parental Bonding Instrument, and the Purpose in Life Test. In addition, multivariate logistic regression analysis was performed to identify any response pattern predictors. RESULTS: Participants were divided into 4 groups based on response patterns in the changes of total SCS scores of the EXMIND group. The first group consisted of 15 participants who responded positively to MBI, but negatively to the existential approach (A group). The second group consisted of 23 participants who responded negatively to MBI, but positively to the existential approach (B group). The third group consisted of 20 participants who responded positively to both MBI and the existential approach (C group). The fourth group consisted of only 2 participants who responded negatively to both MBI and the existential approach (D group). Participants who responded positively to both MBI and the existential approach (C group) reported more maternal overprotectiveness than the other participants (groups A, B, and D). CONCLUSIONS: The present findings suggest that maternal overprotection may predict consistent improvement of self-compassion during EXMIND therapy.

Lithium in drinking water and suicide prevention: The largest nationwide epidemiological study from Japan.

OBJECTIVES: The aims of the present study thus were (a) to further investigate the association between lithium levels in drinking water and suicide rates by adjusting relevant factors using the so far largest available dataset in Japan, (b) to confirm sex differences, (c) to estimate the effects of long-term exposure to trace lithium, (d) to investigate the effects of drinking bottled instead of tap water, and (e) to exploratorily investigate which lithium levels may be associated with lower suicide rates. METHODS: Mean lithium levels in drinking water of all 808 cities and wards (ie, 785 cities of 46 prefectures and 23 wards of Tokyo) in Japan were examined in relation to mean suicide standardized mortality ratios (SMRs) during the 7 years from 2010 to 2016. Multiple regression analyses adjusted for the size of each population were used to investigate the association of lithium levels with suicide SMRs with adjustments for relevant factors. RESULTS: The adjusted model showed significant inverse associations of lithium levels with total and male SMRs, but not with female SMRs. Neither the proportion of residents who continued to live in the same city nor the consumption of bottled water changed the association between lithium levels and suicide SMRs. Finally, it was 30 µg/L or more that was associated with lower suicide SMRs. CONCLUSIONS: The present findings reconfirm the inverse association between lithium levels in drinking water and suicide rates particularly in the male population.

Occurrence of highly radioactive microparticles in the seafloor sediment from the pacific coast 35 km northeast of the Fukushima Daiichi nuclear power plant.

To understand the properties and significance of highly radioactive particles in the marine environment, we have examined seafloor sediment with a radioactivity of ∼1200 Bq/kg (dry weight; after decay correction to March 2011) collected 35 km northeast of the Fukushima Daiichi Nuclear Power Plant (FDNPP). Among the 697 highly radioactive particles separated from the sediment, two particles, D1-MAX and D1-MID, had a total Cs radioactivity of ∼56 and 0.67 Bq (after decay correction to March 2011), respectively. These particles were characterized with a variety of electron microscopic techniques, including transmission electron microscopy. The 134Cs/137Cs radioactivity ratio of D1-MAX, 1.04, was comparable to that calculated for Unit 2 or 3. D1-MAX consisted mainly of a Cs-rich microparticle (CsMP) with a silica glass matrix. The data clearly suggested that D1-MAX resulted from a molten core-concrete interaction during meltdowns. In contrast, D1-MID was an aggregate of plagioclase, quartz, anatase, and Fe-oxide nanoparticles as well as clay minerals, which had adsorbed soluble Cs. D1-MID was likely a terrestrial particle that had been transported by wind and/or ocean currents to a site 35 km from the FDNPP. The radioactive fractions of D1-MAX and D1-MID were 15% and 0.36%, respectively, of the total radioactivity in the bulk sediment. These highly radioactive particles have a great impact on the movement of radioactive Cs in the marine environment by carrying condensed Cs radioactivity with various colloidal and desorption properties depending on the host phase.

Adjunctive bright light therapy for treating bipolar depression: A systematic review and meta-analysis of randomized controlled trials.

OBJECTIVES: Bright light therapy (BLT) was reported as an effective adjunctive treatment option for bipolar disorder. Previous meta-analytic study showed that augmentation treatment with light therapy significantly decreased the severity of bipolar depression. However, most of included studies were case-control studies and several of them focused on BLT that was provided in combination with sleep deprivation therapy. METHODS: In this meta-analysis, we used several electronic databases to search the studies and included only randomized controlled trial (RCT) studies to compare BLT with control experimental groups for treating bipolar depression with pharmacological treatment to clarify the adjunctive efficacy of BLT. We searched the databases of EMBASE, MEDLINE, Scopus, The Cochrane Central Register of Controlled Trials, the Cumulative Index to Nursing and Allied Health Literature, and Clinicaltrials.gov for studies published in English until September 19, 2019. Two researchers conducted the literature screening, data extraction, and methodological quality assessment independently. The main outcome was the response rate and remission rate. We used the Review Manager 5.3 Software for the meta-analysis. RESULTS: Four trials with a total of 190 participants (intervention: 94, control: 96) with bipolar depression were evaluated to gauge the effects of light therapy. The meta-analysis showed risk ratios of 1.78 (95% CI 1.24-2.56, p = .002; I2  = 17%) demonstrating a significant effect of light therapy in the response rate of bipolar disorder. The meta-analysis shows risk ratios of 2.03 (95% CI 0.48-8.59, p = .34; I2  = 67%) demonstrating no significant effect of light therapy in the remission rate of patients with bipolar disorder. None of the articles reported any serious adverse effects. Manic switch rate was 1.1% in the light therapy group and 1.2% in the control group. CONCLUSIONS: Bright light therapy is an effective treatment for reducing depression symptoms among patients with bipolar depression.

Lithium in drinking water and crime rates in Japan: cross-sectional study.

BACKGROUND: In pharmacological doses, lithium successfully treats bipolar disorder and it can reduce violent crimes committed by individuals with this disorder. AIMS: To investigate whether naturally occurring lithium in drinking water lowers rates of violent crime in the general population. METHOD: We examined lithium levels in the drinking water of the 274 municipalities of Kyushu Island in Japan and compared these with the crime rates in each municipality. RESULTS: We found that lithium levels were significantly and inversely associated with crime rates in 2009. CONCLUSIONS: Our findings suggest that even very low levels of lithium in drinking water may play a role in reducing crime rates in the general population.

Association between lithium in tap water and suicide mortality rates in Miyazaki Prefecture.

BACKGROUND: Most studies have reported that suicide mortality rates are negatively associated with lithium levels in tap water; however, a few studies showed either no association or a positive association. Thus, the association between suicide mortality and lithium levels in tap water remains controversial. To clarify the association, our study evaluated the association between lithium levels in tap water and suicide mortality rates in Miyazaki Prefecture of Japan, after adjusting for confounding factors. METHODS: We measured lithium levels in tap water across the 26 municipalities of Miyazaki Prefecture in Japan. We examined the standardized mortality ratio (SMR) for suicide in each municipality and used the data as the average suicide SMRs over 5 years (2009-2013). Weighted least-squares regression analysis, adjusted for the size of each municipality's population, was used to investigate the association between lithium levels in tap water and suicide SMRs. In addition to a crude model, in an adjusted model, potential confounding factors (proportion of elderly people, proportion of one-person households, annual marriage rate, annual mean income, unemployment rate, the density of medical doctors per 100,000 people, annual total rainfall, and proportion of people with a college education or higher) were added as covariates. RESULTS: We showed that male and female suicide SMRs were not associated with lithium levels in tap water in Miyazaki Prefecture. After adjusting for confounders, male suicide SMRs were significantly and positively associated with the proportion of elderly people in the population and annual total rainfall, and female suicide SMRs were associated with the proportion of elderly people in the population. CONCLUSIONS: No association between lithium levels in tap water and suicide mortality rates was found in Miyazaki Prefecture.

More Purpose in Life and Less Novelty Seeking Predict Improvements in Self-Compassion During a Mindfulness-Based Intervention: The EXMIND Study.

OBJECTIVES: Recently, a 4-week mindfulness-based intervention followed by a 4-week existential approach was found to be as effective for increasing self-compassion as an 8-week mindfulness-based intervention. The purpose of the present study was to identify the factors that predicted change in self-compassion during the 8-week mindfulness-based intervention. METHODS: Fifty-seven of the 61 completers of the 8-week mindfulness-based intervention provided baseline, 4-week, and 8-week self-compassion scale scores. The mean age of the 47 females and 10 males was 49.6 years. Pearson's correlation coefficients were generated on the associations between the change of total self-compassion scale scores from baseline to 8 weeks with age; gender; and the baseline scores on the Temperament Evaluation of Memphis, Pisa and San Diego Auto-questionnaire, Temperament and Character Inventory (TCI), Mini-Mental State Examination, Japanese Adult Reading Test, Young Mania Rating Scale, Hamilton Rating Scale for Depression, Parental Bonding Instrument, and purpose in life (PIL). Multiple regression analysis was performed to identify the predictors of the change in total self-compassion scale scores. RESULTS: Novelty seeking (TCI) was significantly and negatively associated with the change in total self-compassion scale scores, whereas the PIL scores were significantly and positively associated with the change in total self-compassion scale scores. Novelty seeking was not significantly associated with baseline, 4-week, or 8-week total self-compassion scale scores, whereas the PIL scores were significantly and positively associated with baseline, 4-week, and 8-week total self-compassion scale scores. The limitation of the present study was a relatively small number of subjects which deterred a more sophisticated analysis of the pathways involved. CONCLUSIONS: The present findings suggest that more PIL and less novelty seeking predict improvements in self-compassion during mindfulness-based interventions, although novelty seeking might substantially predict the improvement but self-compassion scale and PIL might somewhat conceptually overlap.