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For years, the chemical injection process has aided construction works by increasing the strength and water-sealing efficiency of sandy soil. Despite its growing popularity in projects, such as seismic strengthening and liquefaction mitigation, a unified understanding of how chemically treated soil develops its strength, especially under static conditions, remains elusive. Some studies have proposed that strength is derived from the tensile effects of dilatancy, where shearing of the sandy soil causes expansion, creating tension in the interstitial hydrogel and resulting in negative pressure that consolidates the soil particles. Other studies, however, attribute this strength development to the volumetric shrinkage of the hydrogel, which the authors argue confines and compresses the sandy soil particles. Challenges are encountered with this theory, particularly with respect to the consistency of the volumetric shrinkage measurements and the timing of these measurements in relation to changes in soil strength. The aim of the current research is to shed light on this mechanism by using consolidation drainage triaxial compression (CD) tests to measure the cohesive strength and internal friction angle of chemically enhanced soil. By eliminating the dilatancy-induced negative pressure effects and coupling this with an analysis of the molecular structure of the hydrogel, the present study provides an in-depth look at the strength development mechanism and its durability. This holistic approach not only fills in the existing gaps in the understanding of this mechanism, but also paves the way for optimized construction techniques.

Objective: Traumatic childhood experiences such as domestic violence and bullying have been reported to be associated with insomnia in adulthood. However, little evidence is available for the long-term effects of childhood adversity on workers' insomnia worldwide. Our objective was to examine whether childhood experiences of bullying and domestic violence are associated with insomnia in workers in adulthood., Methods: We used survey data from a cross-sectional study of the Tsukuba Science City Network in Tsukuba City, Japan. Workers aged 20 to 65 years (4509 men and 2666 women) were targeted. Binomial logistic regression analysis was performed with the Athens Insomnia Scale as the objective variable., Results: Binomial logistic regression analysis showed that childhood bullying and domestic violence experience of childhood bullying and domestic violence were associated with insomnia. As for the experience of domestic violence, the higher the time of experience, the higher the odds ratio of insomnia., Conclusions: It may be useful to focus on childhood traumatic experiences regarding insomnia in workers. In the future, objective sleep time and sleep efficiency should be evaluated using an activity meter and other methods to verify the effects of bullying and domestic violence experiences., Competing Interests: Competing interests: Daisuke Hori, Shotaro Doki, Shinichiro Sasahara, and Ichiyo Matsuzaki are volunteer members of the Occupational Health Committee of Tsukuba Science City Network., (Copyright: © 2023 Muroi K et al.)

Background: The present study aimed to investigate whether insomnia is associated with suicidal ideation (SI) among Japanese workers by conducting a multi-level analysis with sense of coherence (SOC) as a random effect., Participants and Procedure: A cross-sectional survey was conducted among 19,481 workers in Tsukuba, Japan. Data from 7,175 participants aged 20-65 years were included in the analysis. The Athens Insomnia Scale (AIS) was used as the independent variable, and SI over the past year was used as the dependent variable. SOC was measured using the five-point SOC-13 scale, and socioeconomic and health factors were investigated as covariates. Participants were divided into three groups (low, medium, and high) based on their SOC scores. Multilevel logistic regression analysis was performed to calculate odds ratios (OR) and 95% confidence intervals (95% CI)., Results: In the high-SOC group, only one person had SI. In a multi-level logistic analysis that excluded the high SOC group, insomnia was found to be associated with SI (OR = 2.26, 95% CI [1.75, 2.93]). Furthermore, the AIS sub-items "Final awakening earlier than desired" (OR = 1.26, 95% CI [1.05, 1.50]) and "Sense of well-being during the day" (OR = 1.63, 95% CI [1.34, 1.99]) were associated with SI. 8.95% or 11% of the variation in the presence or absence of SI was found to be explained by differences between SOC groups., Conclusions: The study highlights that insomnia is associated with SI, and that high SOC may reduce SI even under insomnia. Future longitudinal studies are needed to confirm whether high SOC reduces SI due to insomnia., Competing Interests: The authors declare no conflict of interest., (Copyright © Institute of Psychology, University of Gdansk.)

Background: It remains unclear how fear of COVID-19 and resilience are related to psychological distress based on occupations among healthcare workers (HCWs) in hospitals treating patients with COVID-19. We conducted a survey on the mental health of HCWs during the COVID-19 pandemic to determine the relationship between factors such as fear of COVID-19 and resilience as well as mental distress in each occupation of HCWs., Methods: We conducted a web-based survey among HCWs at seven hospitals treating COVID-19 patients in Japan from December 24, 2020 to March 31, 2021. A total of 634 participants were analyzed, and information regarding their socio-demographic characteristics and employment status was collected. Several psychometric measures were used, including the Kessler's Psychological Distress Scale (K6), the fear of COVID-19 Scale (FCV-19S), and the Resilience Scale (RS14). Factors related to psychological distress were identified by logistic regression analysis. The association between job title and psychological scales was examined by one-way ANOVA, and t -tests were conducted to examine the association between the FCV-19S and hospital initiatives., Results: It was found that nurses and clerical workers were associated with psychological distress without considering FCV-19S or RS14; in a model that included FCV-19S, FCV-19S was associated with psychological distress, but job title was not; when RS14 was considered, resilience was protective. In terms of occupation, FCV-19S was lower among physicians and higher among nurses and clerical workers, while RS14 was higher among physicians and lower among other occupations. Having access to in-hospital consultation regarding infection control as well as to psychological and emotional support was associated with lower FCV-19S., Conclusion: Based on our findings, we can conclude that the level of mental distress differed by occupation and the differences in the fear of COVID-19 and resilience were important factors. In order to provide mental healthcare for HCWs during a pandemic, it is important to create consultation services that enable employees to discuss their concerns. In addition, it is important to take steps to strengthen the resilience of HCWs in preparation for future disasters., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Midorikawa, Tachikawa, Kushibiki, Wataya, Takahashi, Shiratori, Nemoto, Sasahara, Doki, Hori, Matsuzaki, Arai and Yamagata.)

Background: The rapid introduction of teleworking due to the coronavirus disease 2019 pandemic has led to concerns about increases in cyberbullying (CB) worldwide. However, little is known about workplace CB in non-Western countries. The first objective was to clarify the prevalence and characteristics regarding workplace CB victimization in Japan. The second objective was to demonstrate the psychological outcomes of CB victimization in combination with traditional bullying (TB)., Methods: We conducted an anonymous, cross-sectional, Internet-based survey targeting regular employees in Japan (N = 1200) in January 2021. We investigated CB victimization using the Inventory of Cyberbullying Acts at Work and TB victimization by using the Short Negative Act Questionnaire. Possible explanatory factors for TB/CB victimization were sociodemographic variables, personality trait, chronic occupational stress, organizational climate, and gratitude at work. We also measured psychological distress, insomnia, and loneliness to assess adverse effects of workplace bullying. Two-step cluster analysis was used in determining the patterns combined with TB and CB victimization. Hierarchical binomial logistic regression analysis was used., Results: In total, 8.0% of employees reported experiencing CB on a weekly basis. CB victimization was associated with younger age, managerial position, higher qualitative workload, and active information dissemination via the Internet, and frequency of teleworking. Three clusters based on TB and CB victimization patterns were identified: those who belong to the first cluster suffered neither from TB and CB (81.0%), the second cluster suffered only from TB (14.3%), and the third cluster suffered from both TB and CB (4.8%). The third cluster exhibited higher odds ratios (ORs) and 95% confidence intervals (CIs) for psychological distress (OR = 12.63, 95% CI = 4.20-38.03), insomnia (OR = 6.26, 95% CI = 2.80-14.01), and loneliness (OR = 3.24, 95% CI = 1.74-6.04) compared to the first cluster., Conclusions: These findings firstly clarify the prevalence and correlated factors of CB victimization among employees in Japan. Further, we showed that psychological wellbeing can be impaired by the coexistence of TB and CB. Our research could be the first step to develop the effective countermeasures against workplace CB., (© 2022. The Author(s).)

Background: Ibaraki's Amabie-chan is a COVID-19 infection control system unique to Ibaraki prefecture, Japan. It requires residents to register each time they visit events, commercial facilities, and restaurants. The number of registrations has been limited, and its function alerting about people positive for COVID-19 infection seems not to be working. Nevertheless, registration with the system might have some impact on the user's behavior. In the current preliminary survey, the possible impact of Ibaraki's Amabie-chan on infection prevention behavior and fear of COVID-19 was investigated., Methods: A cross-sectional, web-based, anonymous, and self-administered survey was conducted at two workplaces in Tsukuba Science City, Ibaraki, Japan. The first survey was conducted at one of the workplaces in November 2020, and the second survey, at the other workplace in February 2021. Variables of interest were sex, age group, marital status, employment status, Ibaraki's Amabie-chan use, COVID-19 Contact-Confirming Application use, ten items of infection prevention behaviors, and fear of COVID-19. Hierarchical linear regression analysis was performed., Results: In both surveys, use of Ibaraki's Amabie-chan was significantly associated with COCOA use and with "physical condition management such as body temperature measurement." No association was found with other infection prevention behaviors or with fear of COVID-19., Conclusions: Our findings did not provide sufficient evidence for the effectiveness of Ibaraki's Amabie-chan in regard to users' infection control behavior. Further detailed study is needed to investigate the effectiveness in terms of infection prevention and the cost-effectiveness of Ibaraki's Amabie-chan.

Objectives: Psychological distress is a worldwide problem and a serious problem that needs to be addressed in the field of occupational health. This study aimed to use artificial intelligence (AI) to predict psychological distress among workers using sociodemographic, lifestyle and sleep factors, not subjective information such as mood and emotion, and to examine the performance of the AI models through a comparison with psychiatrists., Design: Cross-sectional study., Setting: We conducted a survey on psychological distress and living conditions among workers. An AI model for predicting psychological distress was created and then the results were compared in terms of accuracy with predictions made by psychiatrists., Participants: An AI model of the neural network and six psychiatrists., Primary Outcome: The accuracies of the AI model and psychiatrists for predicting psychological distress., Methods: In total, data from 7251 workers were analysed to predict moderate and severe psychological distress. An AI model of the neural network was created and accuracy, sensitivity and specificity were calculated. Six psychiatrists used the same data as the AI model to predict psychological distress and conduct a comparison with the AI model., Results: The accuracies of the AI model and psychiatrists for predicting moderate psychological distress were 65.2% and 64.4%, respectively, showing no significant difference. The accuracies of the AI model and psychiatrists for predicting severe psychological distress were 89.9% and 85.5%, respectively, indicating that the AI model had significantly higher accuracy., Conclusions: A machine learning model was successfully developed to screen workers with depressed mood. The explanatory variables used for the predictions did not directly ask about mood. Therefore, this newly developed model appears to be able to predict psychological distress among workers easily, regardless of their subjective views., Competing Interests: Competing interests: SS is the Chair of the Occupational Health Technical Committee, Tsukuba Science City Network; SD, YO and DH are members of the Occupational Health Technical Committee and the other authors are members of the Occupational Health Technical Committee Working Group. None of the authors received remuneration., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Study Objectives: Although associations between sleep quality and environmental factors and nutrient intake have been reported, interactions between these factors have not been elucidated in detail. Therefore, this cross-sectional study examined the effects of regular exercise and nutrient intake on sleep quality using the Pittsburgh Sleep Quality Index (PSQI), which is the most frequently used index for sleep evaluation., Methods: The participants included 378 individuals aged 40 years or older living in Shika Town, Ishikawa Prefecture. Of these individuals, 185 met the inclusion criteria. The participants completed a self-administered questionnaire assessing lifestyle habits and frequency and duration of exercise, the PSQI, and the brief-type self-administered diet history questionnaire (BDHQ) on nutrient intake., Results: A two-way analysis of covariance on regular exercise and PSQI scores indicated that protein intake (17.13% of energy) was significantly higher in the regular exercise and PSQI ≤10 groups than in the non-regular exercise or PSQI ≥11 groups (p = 0.002). In a multiple logistic regression analysis with PSQI scores (≤10 and ≥11), protein intake was a significant independent variable in any of the models adjusted for confounding factors such as age, sex, body mass index, current smoker, and current drinker (OR: 1.357, 95% CI: 1.081, 1.704, p = 0.009) in the regular exercise group but not in the non-regular exercise group.Conclusions We identified a positive relationship between sleep quality and protein intake in the regular exercise group. These findings suggest that regular exercise at least twice a week for 30 minutes or longer combined with high protein intake contributes to good sleep quality., Competing Interests: The authors have declared that no competing interests exist.

Near-infrared spectroscopy (NIRS) is a non-invasive functional brain imaging technique. NIRS is suitable for monitoring brain activation during social interactions. One of the omnipresent social interactions for employees is saying thank you and being thanked. It has been demonstrated that expressing and receiving gratitude leads to employees' well-being and performance. To date, there have been no neuroimaging studies that monitor brain activity when receiving gratitude. Thus, we designed an experiment using NIRS to monitor brain function while listening to a letter of gratitude read by a coworker. We hypothesized that listening to a letter of gratitude read aloud by a co-worker in a face-to-face setting would have different effects on PFC activity than listening to a conversation about a neutral topic. We recruited 10 pairs of healthy right-handed employees. They were asked to write a letter of gratitude to their partner 1 week before the experiment. In the experiment, each pair sat face-to-face and read their letters aloud to each other. We evaluated changes in mood state before and after the experiment. NIRS was measured in each participant while they listened to their peers in the experimental condition (gratitude letter) and control condition (talking about the weather and date). The results suggested that negative mood state decreased after the experiment. Moreover, there were interaction effects between conditions and periods. Although further studies are needed to confirm the interpretation, our findings suggested that experience of being thanked was accompanied by prefrontal cortex activation., Competing Interests: The authors have declared that no competing interests exist.

Early-life adversities are considered to have long-term impact on health. There have been many studies regarding the experience of being bullied and its harmful psychological influence, but such influence on workers remains to be investigated in Japan. We therefore aimed to examine the prevalence of workers with experiences of being bullied or bullying others during childhood and adolescence and to clarify the relation between those experiences and current psychological distress. A cross-sectional study using an anonymous self-report web questionnaire was conducted in November 2017. The study population was 19,481 workers belonging to the Tsukuba Science City Network, and we analyzed the data of 6,015 participants (3,715 men and 2,300 women, aged between 20 years and 59 years). The percentages of participants with experiences of being bullied were 51.5% for men and 56.2% for women; those with experiences of bullying others were 36.5% of men and 29.4% of women. Relations between experiences of bullying and psychological distress were assessed using Chi-squared tests. Logistic regression analyses with psychological distress as an objective variable and experiences of bulling as explanatory variables were performed using those who had no bulling experiences as control. In both men and women, experiences of being bullied were significantly associated with psychological distress after adjustment socioeconomic factors (the odds ratios were 1.26 for men (95% CI = 1.05-1.52) and 1.72 for women (95% CI = 1.39-2.13)). Consideration of past social experiences, such as being bullied, is useful for mental health management among workers reporting psychological distress.

Aim: A generic bioanalytical method was developed to quantify therapeutic IgG1 monoclonal antibodies (mAbs) in mouse sera by combining an easy sample preparation method with LC/MS using selected reaction monitoring. Materials & methods: Rituximab and trastuzumab were used as model mAbs. A synthetic stable isotope-labeled peptide or a stable isotope-labeled mAb was used as an internal standard. The method feasibility was evaluated by a collaborative study involving six laboratories. Results: The calibration curve ranged from 1.0 to 1000.0 μg/ml (correlation coefficient >0.99). The validation parameters including selectivity, linearity of calibration curve, accuracy and precision met the predefined acceptance criteria. Conclusion: Our method is a useful bioanalytical method for the quantification of therapeutic IgG mAbs in nonclinical animal studies.

Background: Flourishing, defined as the coexistence of hedonic and eudaimonic well-being, is the most favorable end of the mental health spectrum. A growing body of evidence has demonstrated the association between flourishing mental health and favorable work-related outcomes. However, epidemiology of flourishing mental health is scarce in Japan. Moreover, the relationship between flourishing mental health and occupational stress has not been elaborated. Therefore, the aim of this study was to elucidate (1) the prevalence of flourishing mental health and (2) the association between flourishing mental health and occupational stress among Japanese workers., Methods: The present survey was conducted in from February to March 2017 via an anonymous, self-administered, and web-based questionnaire among workers in Tsukuba Science City, Japan. Mental Health Continuum Short Form was used to assess flourishing mental health. We performed binomial logistic regression analyses to calculate the adjusted odds ratios (AOR) and 95% confidence intervals (CI) of occupational stress for flourishing mental health, controlling for sociodemographic factors., Results: A total of 7012 respondents (4402 men, 2610 women) were analyzed. The overall prevalence of flourishing mental health among the respondents was 12.4%. Full-time (permanent) workers were less likely to be flourishing. Reward from work (AOR = 2.34, 95% CI = 2.04-2.68), support from colleagues and superiors (AOR = 1.67, 95% CI = 1.44-1.94), and workload (AOR = 1.19, 95% CI = 1.05-1.36) were positively associated with flourishing mental health, whereas mental workload (AOR = 0.65, 95% CI = 0.57-0.75) was inversely associated with flourishing mental health., Conclusions: The findings of the present study shed light on the association between flourishing mental health and occupational stress.

Non-regular employment is increasing and its mental health impact is a globally important problem. In Japan, non-regularly employed researchers are increasing, especially within young age groups, because employment quotas were not sufficiently expanded against rapid increasing number of doctorate holders. It is therefore important to understand the relationship between non-regular employment and mental health. The significance of our research is to contribute to the improvement of researchers' mental health by clarifying the influence of employment status on psychological distress. We conducted a cross-sectional, web-based survey in 2017 via an anonymous, self-administered questionnaire distributed to workers in Tsukuba Science City, Japan. The survey questionnaire items included employment status, psychological distress, occupational stress, sex, age, and income. We analyzed 2,762 valid responses in two categories (1,850 regular employment, 912 non-regular employment) and two subcategories based on age according to the definition of "young researcher" by the Ministry of Health, Labor and Welfare (20-39 years vs. 40-59 years). Psychological distress was defined as a total K6 score of 5 or greater. Binomial logistic regression was used to calculate odds ratios and 95% confidence intervals for psychological distress. Non-regular employment was significantly associated with psychological distress in the age 20-39 group but not in the age 40-59 group. At the age 20-39 group, a negative association was shown between psychological distress and reward from work (i.e., pride in their job, ability utilization, and sense of accomplishment). Support to increase psychological work rewards may be important in reducing psychological distress for young non-regularly employed researchers.

Previous studies have reported an association between family relationships and suicidal behavior, and found that people with high suicidal ideation are not likely to consult with others about their distress. An effective consulting service is therefore necessary for such individuals. Crisis hotlines are effective for reducing suicide risk, but their associated suicide ideation rate and odds ratio of family problems children remain unclear. The present study investigated the suicidal ideation rate and odds ratio of callers under 20 years of age (N = 24,333) with family problems to the Japanese crisis hotline in 2012. There were 5,242 (21.5%), 18,061 (74.2%), and 1,030 (4.2%) calls related to family problems, other problems, and both, respectively. The suicidal ideation rate and odds ratio of callers with family problems were 2.2% and 0.426, respectively. This result suggested that callers with family problems have a significantly lower rate and odds ratio for suicidal ideation compared with others. However, some associations with a high suicide ideation rate were found for individual items among callers with family problems such as abuse (20.4%), family breakdown (16.1%), and domestic violence (10.6%). Further studies are needed to understand the suicidal ideation of callers with family problems and develop more effective preventive strategies., Competing Interests: The authors have declared that no competing interests exist.

Background: A growing body of evidence has demonstrated the associations between social capital and health. In residential or geographical areas, social capital has attracted attention for its protective effects against suicide. However, to this date, the relationship between social capital and suicidal ideation is not fully elaborated in the occupational setting. Therefore, the aim of the present study was to examine the association between workplace social capital and suicidal ideation in the past year among employees in Japan., Methods: A cross-sectional, web-based survey was conducted in February/March 2017 via an anonymous self-administered questionnaire distributed to workers in Tsukuba Science City, Japan. Binomial logistic regressions were used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) for suicidal ideation in the past year, controlling for age group, marital status, educational attainment, and annual household income. The results were shown stratified by sex and occupation., Results: In total, 7255 of 19,481 workers responded, out of which we could analyze 6325 responses (4030 men, 2295 women). The prevalence of suicidal ideation in the past year was 5.9% for men and 7.8% for women. Low workplace social capital was statistically significantly associated with suicidal ideation both for men (OR = 2.57, 95% CI = 1.72-3.83) and for women (OR = 1.75, 95% CI = 1.15-2.66), compared with high workplace social capital after controlling for socioeconomic factors., Conclusion: Higher workplace social capital was associated with a reduced risk of suicidal ideation in the past year. Promoting workplace social capital could contribute to preventing suicide among employees in Japan.

It is important to select an appropriate surrogate matrix for preparing calibration standards and quality control samples while quantitatively assaying for endogenous substances, because a blank matrix that does not contain the endogenous substance cannot be derived from the species from which the target study samples are collected. This is because the assay results might be affected, depending on the characteristics of the analyte in the surrogate matrix. Our discussion group that participated in the Japan Bioanalysis Forum discussed the recommended selection strategies, focusing on large and small molecules in ligand binding assays and LC-MS, respectively. We established an efficient selection strategy for a surrogate matrix, with simple compositions as the first candidates stated in this article.

The present study aimed to survey systems in Japanese companies for supporting workers returning to work from sickness absence due to mental illness. A questionnaire survey was mailed to 3,545 companies. Support systems for return to work, sick leave, and multiple sick-listed (MSL) workers were examined. A total of 161 companies responded to the survey (response rate: 4.5%). About 80% of the companies expressed difficulty in dealing with workers with mental health problems. About half of all companies reported having reset period and financial compensation systems, as well as gradual resumption and trial attendance systems. Most large companies tended to have reset period and trial attendance systems. No association was found between company size and MSL rates. The most frequent diagnosis among workers was depression, and the mean number of sick leave days was 275.3. Although there might have been a selection bias due to the low response rate, the results of this study are expected to be useful for companies when formulating employment systems.

Objectives: The aim of this study was to examine potential differences of the associations between mental health and lifestyle factors across a wide range of age., Methods: In August/September 2011, data were collected from 4693 males (age 51.6 ± 19.5) and 5678 females (age 52.4 ± 19.4) living in Kanazawa, Japan. A cross-sectional community-based survey was conducted with self-administered questionnaire including the General Health Questionnaire (GHQ) 12-item version, sociodemographic, and lifestyle factors. Associations between the GHQ scores and other variables were examined using two-way analysis of variance (ANOVA) followed by multiple comparisons and logistic regression stratified by age and gender., Results: Multiple comparisons indicated that people aged 20-39 or 40-64 had higher GHQ scores than older aged. The two-way ANOVA revealed significant interaction between body mass index and age group, and between exercise and age group. Overweight or underweight males aged 40-64 had poorer mental health than those at normal weight. In the elderly, being underweight was significantly associated with poor mental health. There were no significant effects of exercise on mental health for young adults. The logistic regression showed significant negative effects of short-time sleep in adults., Conclusions: The associations between mental health and lifestyles differ across age groups. Further study is needed to reveal effects of aging on lifestyle and mental health with a longitudinal design., Competing Interests: The authors declare that they have no competing interests.

Background: In Japan, since 2006, participation in a 1-year residency programme by all dentists who have passed the National Board Dental Examination has been mandatory. Therefore, a 'matching system' has become necessary for dental students in their final year to decide their desired residency facility, but the rate of matching in dental schools located in rural areas is still low. Aim : The principal aim of this study was to elucidate the background factors influencing the selection of residency facilities by dental students in rural areas to facilitate the training of dentists working in local communities. Methods : Using the matching results from 554 final-year students of Kagoshima University Faculty of Dentistry from 2005 to 2013, multiple logistic regression analysis was performed on the background factors of the subjects. Results : Concerning the selection of the residency facility, it was verified that there were strong background factors for subjects to select residency facilities in their hometown, but compared with subjects from other regions, those from Kinki and Kanto regions did not select residency facilities in their hometown. Compared with males, a significantly higher number of females selected residency facilities in their hometown. A significantly higher number of subjects who repeated a school year selected the residency facility of their alma mater. Conclusion : In dental schools of national universities located in provinces, the establishment of a quota system for students from the region, where possible, is one of the most effective steps for securing future dental trainees.

Objectives: The objective of this study was to clarify the relationship between sickness presenteeism and the degree of awareness of company regulations regarding financial compensation for absenteeism., Methods: An Internet-based survey of 258 full-time workers who had more than 28 days of sickness absence due to mental health problems was conducted. Workers were categorized as having either low or high sickness presenteeism, and awareness and presence or absence of systems for return to work and duration of financial compensation were compared between groups., Results: The following factors were significantly related to high sickness presenteeism based on logistic regression analyses: working for a private company (odds ratio [OR]=2.57; 95% confidence interval [CI]=1.10-5.99); recognition of a gradual resumption system (OR=3.89, 95% CI=1.02-14.81); and awareness regarding the duration of financial compensation (OR=1.04, 95% CI=1.01-1.07)., Conclusions: No relationship was found between mental sickness presenteeism and presence or absence of systems for return to work in our multivariate analysis; however, a relationship was apparent between sickness presenteeism and characteristics of the workers' companies. These results are expected to contribute to research involving human resources and occupational health.

Via a large scale cross-sectional study among Japanese white color workers, the authors aimed to elucidate: (1) the distributions of Sense of Coherence (SOC), which reflect stress coping abilities, (2) the distributions of the Brief Scale for Coping Profile (BSCP) which reflect coping profiles for stressors; (3) and the association between SOC and BSCP. Anonymous self-administered questionnaires were sent to 20,742 employees at educational and research institutions in Tsukuba Research Park City. A total of 12,009 (57.9%) workers completed and returned the questionnaire; 10,317 workers without missing data were analyzed. SOC scale scores and BSCP subscale scores differed by gender, age, and other demographic features. Among the BSCP subscales, workers whose SOC scale scores were higher tended to adopt a problem-focused coping profile, whereas workers whose SOC scale scores were lower adopted an emotion-focused coping profile. The coping profile that workers adopted depended on their background and demographic characteristics. Stronger SOC allowed one to adopt a problem-focused coping profile that allows for better coping with work-related stressors.

Objectives: Overweight and poor psychological well-being are becoming serious health issues in the Japanese workplace. Concurrence of those physical and mental conditions has been pointed out, especially in middle-aged workers. Therefore, we tried to determine common risk factors for body weight gain and the deterioration of psychological well-being in male middle-aged office workers using a five-year follow-up study., Methods: We administered General Health Questionnaire-12 (GHQ-12) as an indicator of psychological well-being to 110 male workers with ages ranging from 40-59 years, and analyzed the influence of several psychological factors, namely sense of coherence (SOC), health locus of control (HLC), and lifestyle variables such as exercise frequency, alcohol intake, smoking status, and dietary intake on changes of body mass index and GHQ-12 score., Results: McNemar's chi-squared test showed significant concurrence of weight gain and deterioration of psychological well-being after five-year follow-up. Low-SOC score, low frequency of exercise, and high-dietary intake at supper were significantly associated with both weight gain and poorer psychological well-being in workers, results which were supported by multiple regression analysis., Conclusions: These results suggest that exercise and calorie restriction seem to prevent weight gain and promote psychological well-being in workers. Low SOC, which implies difficulty in coping with stress, may be an important risk factor not only for deterioration of psychological well-being but also for becoming overweight. These assumptions must be confirmed by conducting future intervention studies on SOC and lifestyle including exercise and eating behavior.

Objectives: The number of elderly workers has also been increasing and poor psychological well-being in elderly workers has been reported. The aim of this study is to elucidate the factors that are related to poor psychological well-being in elderly workers., Methods: We administered General Health Questionnaire-12 (GHQ-12) as an indicator of psychological well-being to 330 male elderly workers in the age range of 50-69, and analyzed different psychological factors, namely sense of coherence (SOC), and physical and lifestyle variables such as blood pressure, serum total cholesterol, smoking frequency, alcohol intake, exercise frequency, and body mass index (BMI) that are related to GHQ-12., Results: When the cut-off point of GHQ-12 was 2/3, 97 workers who showed high GHQ-12 score were classified as one group having poor psychological well-being. A statistically significantly lower SOC score, higher stress score, lower frequency of exercise, higher smoking score and higher BMI, but not longer working hours or higher shift work score in the workers with higher GHQ-12 scores were observed than in the workers with normal GHQ-12 scores. Multiple logistic regression analysis showed that the low SCO score, low frequency of exercise, high smoking frequency and high BMI significantly contributed to the high GHQ-12 score., Conclusions: A low SOC score in elderly workers is assumed to be directly related to poor psychological well-being, or via the development of lifestyle problems such as lack of exercise, obesity, and smoking in elderly workers. This assumption must be confirmed by conducting future intervention studies on lifestyle.

In order to confirm the biosynthetic pathway to 1-octen-3-ol from linoleic acid, a crude enzyme solution was prepared from the edible mushroom, Lentinus decadetes. When the reaction was performed in the presence of glutathione peroxidase, which can reduce organic hydroperoxide to the corresponding hydroxide, the amount of 1-octen-3-ol formed from linoleic acid was decreased. At the same time, an accumulation of linoleic acid 10-hydroxide could be detected. The 10-hydroperoxide therefore seems to be an intermediate on the biosynthetic pathway.

We have previously demonstrated that a sense of coherence (SOC), a candidate for a mediating stress factor, is involved in natural killer cell activity (NKCA) reduced in smokers, whereas the relationship among exercise, NKCA and SOC is unclear. To clarify the effects of exercise on SOC and NKCA, we examined the changes in SOC and NKCA before and after health education to encourage exercise. Of one-hundred and one male office workers who received the health education for one year, 27 improved, 65 were unchanged and 9 had deteriorated exercise habits. The repeated measures analysis of variance showed that SOC in workers with improvement in the exercise habit were increased more significantly by the health education than those in workers without improvement (p<0.05). Although the change in NKCA produced by health education was recognized to be significantly different in those who had never smoked from that in current smokers (p<0.05), multiple regression analysis demonstrated that improvement in health practice significantly contributed to increases in both SOC (p<0.01) and NKCA (p<0.05) in never smokers, independently of other psychological factors. These results suggest that subjects with improvement in exercise enhance NKCA through increased SOC in never smokers.

The functions of Tyr420 and Leu607 were analyzed by constructing various site-directed mutants. The mutation at position 420 into Ala and Gly gave bicyclic alpha-and gamma-polypodatetraene in significant amounts, but with a trace amount of tricyclic malabaricatriene. The kinetic data for and the product distribution of the Y420F mutant indicate that the major function of Tyr420 is to stabilize the 6/6-fused bicyclic cation. Mutation experiments on Leu607 demonstrate that the appropriate steric bulk size at position 607 is required to strongly bind with the product-like conformation formed during the polycyclization process. Introduction of the bulkiest Trp residue into 420 or 607 led to the production of a novel monocyclic triterpene having the (5R,6R)-1,5,6-trimethylcyclohexene ring, named neoachillapentaene, indicating that the enzymatic cyclization proceeded via a constrained boat structure. Folding of the squalene molecule into a boat conformation by squalene cyclase has not been reported before.