Deformation Behavior and Microstructure of 6061 Aluminum Alloy Processed by Severe Plastic Deformation Using Biaxial Alternate Forging.

The deformation behavior and microstructure of 6061 aluminum alloy processed by severe plastic deformation (SPD) using biaxial alternate forging that can evaluate the forming limit and mechanical properties of alloys, simultaneously, were investigated in this study. A finite element (FE) analysis on the biaxial alternating forging process, considering the strain-hardening coefficient and forging pass of the material, was conducted. When the strain-hardening coefficient is 0, an average effective strain of 440% was found within a diameter of 4 mm in the core of the workpiece after eight passes, while it was 300% at the same pass number when the strain-hardening coefficient was 0.2. The average effective strain estimated from the FE analysis was about 264% after eight passes of forging, which is considered to be a level of SPD that significantly exceeds the elongation of the raw material. As a result of the tensile test according to the forging pass, after two passes, the strength of the material could be gradually improved without significant degradation of elongation. Even though a large strain of 264% was found after eight passes were applied, deformed grains and twins with no recrystallized structure in optical microstructures with different forging passes were found.

Gender Differences in the Association between Workplace Bullying and Depression among Korean Employees.

Workplace bullying is a prevalent issue with a significant impact on employees' mental health. This study aimed to explore the relationship between workplace bullying and the prevalence of depression, with a particular focus on the role of gender. A total of 12,344 Korean employees aged 19-65 years were included in the study. They completed the Center for Epidemiologic Studies Depression Scale (CES-D) and a score of 16 or higher in CES-D indicated depression. The association between workplace bullying and depression was analyzed using logistic regression analyses. The average CES-D scores were higher for both male and female employees who experienced bullying than for those who did not (p < 0.001). The association between the experience of workplace bullying and the prevalence of depression was statistically significant for both genders, with a stronger correlation observed among male employees (p for interaction < 0.001). Organizations are urged to address workplace bullying, particularly for male employees, through the implementation of anti-bullying strategies and policies, as well as the provision of mental health resources and support.

Direct Conversion of Cell Fate and Induced Endothelial Cells.

Advances in nuclear reprogramming technology have enabled the dedifferentiation and transdifferentiation of mammalian cells. Forced induction of the key transcription factors constituting a transcriptional network can convert cells back to their pluripotent status or directly to another cell fate without inducing pluripotency. To date, direct conversion to several cell types, including cardiomyocytes, various types of neurons, and pancreatic ß-cells, has been reported. We previously demonstrated direct lineage reprogramming of adult fibroblasts into induced endothelial cells (iECs) in mice and humans. In contrast to induced pluripotent stem cells, for which there is consensus on the criteria defining pluripotency, such criteria have not yet been established in the field of direct conversion. We thus suggest that careful assessment of the status of converted cells using genetic and epigenetic profiling, various functional assays, and the use of multiple readouts is essential to determine successful conversion. As direct conversion does not go through pluripotent status, this technique can be utilized for therapeutic purposes without the risk of tumorigenesis. Further, direct conversion can be induced in vivo by gene delivery to the target tissue or organ in situ. Thus, direct conversion technology can be developed into cell therapy or gene therapy for regenerative purposes. Here, we review the potential and future directions of direct cell fate conversion and iECs.

The Association Between Alcohol Use and Suicidal Ideation Among Employees.

OBJECTIVE: The risk of suicide is assessed by identifying the relationship between alcohol-use patterns and suicidal ideation in Korean employees. METHODS: The study involved 13,858 employees who underwent workplace mental health screening at the Workplace Mental Health Institute of Kangbuk Samsung Hospital over a 6-year period between 2014 and 2019. Analysis was performed separately for Alcohol Use Disorders Identification Test-Korea (AUDIT-K) items related to the frequency/volume of alcohol consumption (items 1 to 3, AUDIT-C) and those regarding alcohol dependence/related problems (items 4 to 10, AUDIT-D/P). Subjects were then classified into three groups on the basis of the presence or absence of clinical depression and suicidal ideation. The groups' sociodemographic factors and clinical features of depression, anxiety, and alcohol-use patterns were analyzed with a chi-square test as well as one-way analysis of variance, followed by a post hoc test using the Bonferroni correction. RESULTS: AUDIT-K and AUDIT-D/P scores were significantly associated with the presence or absence of clinical depression as well as the presence or absence of suicidal ideation (p<0.05). However, no significant differences were found among the three groups with regard to the AUDIT-C score (p=0.054). CONCLUSION: Identifying or treating alcohol dependence/related problems can help lower the occurrence of mental health problems, and suicidal ideation in particular, in employees and reduce social costs.

Direct conversion of adult human fibroblasts into functional endothelial cells using defined factors.

We aimed to directly convert adult human dermal fibroblasts (aHDFs) into functional endothelial cells (ECs). Lentiviral vectors encoding endothelial transcription factors (TFs) were constructed. We examined whether five TFs (FOXO1, ER71, KLF2, TAL1, and LMO2) used for the generation of mouse induced ECs (iECs) could convert the aHDFs into human iECs. Twenty-eight days after transduction with lentiviral constructs, 32.1 ± 5.1% cells expressed vascular endothelial (VE)-cadherin. Factor screening revealed that only three factors (3F: ER71, KLF2, and TAL1) were necessary to induce VE-cadherin (+) cells (49.4 ± 3.5%). However, whole transcriptome sequencing showed that VE-cadherin (+) cells were not completely reprogrammed. Mature iECs double-positive for VE-cadherin/Pecam1 (DP cells) with a cobblestone appearance were obtained at a frequency of only 5.1 ± 0.6%. Using whole transcriptome analysis, the potential factors that could block the conversion were screened. Among candidates TWIST1-knockdown enhanced efficiency of conversion. Rosiglitazone, an inhibitor of epithelial-mesenchymal transition (EMT), also improved the conversion efficiency. Moreover, a 2nd second-stage conversion process, in which VE-cadherin (+) cells were incubated for additional two weeks, further enhanced the efficiency. The final protocol for 6 weeks yielded a conversion rate of 19.6 ± 3.0% iECs, defined by DP cells depicting the nature of mature ECs in various analyses. Further analyses revealed that the genetic and epigenetic profiles of iECs resembled those of functional ECs. Collectively, aHDFs can be converted into functional ECs through the transduction of ER71, KLF2, and TAL1, combined with two EMT inhibitors (siTWIST1 and rosiglitazone), followed by 2nd stage conversion.

Bidirectional association between blood pressure and depressive symptoms in young and middle-age adults: A cohort study.

AIMS: To evaluate the bidirectional relationship between blood pressure (BP) and depressive symptoms using a large prospective cohort study. METHODS: Prospective cohort study was performed in 276 244 adults who participated in a regular health check-up and were followed annually or biennially for up to 5.9 years. BP levels were categorised according to the 2017 American College of Cardiology and American Heart Association hypertension guidelines. Depressive symptoms were assessed using Centre for Epidemiologic Studies-Depression (CESD) questionnaire and a cut-off score of ≥25 was regarded as case-level depressive symptoms. RESULTS: During 672 603.3 person-years of follow-up, 5222 participants developed case-level depressive symptoms. The multivariable-adjusted hazard ratios (HRs) [95% confidence interval (CI)] for incident case-level depressive symptoms comparing hypotension, elevated BP, hypertension stage 1 and hypertension stage 2 to normal BP were 1.07 (0.99-1.16), 0.93 (0.82-1.05), 0.89 (0.81-0.97) and 0.81 (0.62-1.06), respectively (p for trend <0.001). During 583 615.3 person-years of follow-up, 27 787 participants developed hypertension. The multivariable-adjusted HRs (95% CI) for incident hypertension comparing CESD 16-24 and ⩾25 to CESD < 16 were 1.05 (1.01-1.11) and 1.12 (1.03-1.20), respectively (p for trend <0.001) and in the time-dependent models, corresponding HRs (95% CI) were 1.12 (1.02-1.24) and 1.29 (1.10-1.50), respectively (p for trend <0.001). CONCLUSIONS: In this large cohort study of young and middle-aged individuals, higher BP levels were independently associated with a decreased risk for developing case-level depressive symptoms and depressive symptoms were also associated with incident hypertension. Further studies are required to elucidate the mechanisms underlying the bidirectional association between BP levels and incident depression.

Vitamin D deficiency and suicidal ideation: A cross-sectional study of 157,211 healthy adults.

OBJECTIVES: Vitamin D deficiency has been reported to be associated with various neuropsychiatric disorders. However, there are few studies addressing deficient vitamin D levels and suicidal ideation. METHODS: Serum vitamin D of 157,211 Korean adult participants were measured using electrochemiluminescence immunoassay. A self-reported questionnaire was used to assess whether participants experienced suicidal ideation. Logistic regression model was used to estimate the odds ratio (OR) of suicidal ideation according to vitamin D levels. The regression was adjusted for a range of covariates. RESULTS: Compared with sufficient vitamin D levels (≥20 ng/mL), deficient vitamin D levels (<10 ng/mL) were significantly associated with the risk of suicidal ideation (OR = 1.138, 95% Cl = 1.027-1.262). However, the OR of suicidal ideation was not significantly different between the vitamin D insufficient group (10-19.99 ng/mL) and sufficient group (≥20 ng/mL) (OR = 0.988, 95% Cl = 0.932-1.047). CONCLUSION: Deficient vitamin D levels were significantly associated with the risk of suicidal ideation. However, the risk of suicidal ideation was not significantly different between the vitamin D insufficient group and sufficient group.

The association of occupational stress and sleep duration with anxiety symptoms among healthy employees: A cohort study.

The aim of this study is to identify occupational stress associated with the development of new-onset anxiety symptoms and the dose-response relationship between sleep duration and the onset of anxiety symptoms. Data from 29,251 healthy employees who had undergone at least two comprehensive health examinations at Kangbuk Samsung Hospital Health Screening Center were analysed. Anxiety symptoms were assessed using the Beck Anxiety Inventory. Occupational stress and sleep duration were measured using a self-reported questionnaire about total sleep time and the Korean Occupational Stress Scale-Short Form (KOSS-SF), respectively. Flexible parametric proportional hazards model used to estimate the hazard ratios. Compared with the groups without case-level anxiety, discomfort in an organizational climate, high job demands, job insecurity, organizational injustice and lack of reward were associated with the onset of case-level anxiety. Compared with less than 6 hr of sleep per day, the beneficial level of sleep duration was 7 ≤ to <9 hr a day. Almost all subscales of job stress were associated with the development of anxiety symptoms. In addition, the efficacious level of sleep duration for reducing the onset of future anxiety symptoms was 7 ≤ to <9 hr a day.

The Relationship between Serum Vitamin D Levels, C-Reactive Protein, and Anxiety Symptoms.

OBJECTIVE: The aim of study is to investigate the relationship between serum vitamin D, c-reactive protein (CRP) levels, and anxiety symptoms. METHODS: Serum vitamin D and CRP levels of 51,003 Korean adult participants were collected retrospectively. Anxiety symptoms were assessed using the Korean version of Beck Anxiety Inventory. Logistic regression was used to estimate the odds ratio (ORs) of anxiety symptoms by serum vitamin D and CRP levels. The regression was adjusted for covariates, and each model was adjusted mutually for vitamin D and CRP levels. RESULTS: Compared with sufficient vitamin D levels (≥20 ng/mL), insufficient (10-19.99 ng/mL) and deficient (<10 ng/mL) vitamin D levels were significantly associated with risk of anxiety symptoms. Also, continuous vitamin D levels were negatively associated with the risk of anxiety symptoms. CRP levels did not affect the relationship between vitamin D levels and risk of anxiety symptoms. CONCLUSION: Insufficient (10-19.99 ng/mL) and deficient (<10 ng/mL) vitamin D levels were significantly associated with risk of anxiety symptoms. After adjusting for CRP levels, the results were not changed, and no evidence of interaction between vitamin D and CRP levels was found. CRP levels did not account for the association between vitamin D levels and risk of anxiety symptoms.

The association of physical activity and sleep duration with incident anxiety symptoms: A cohort study of 134,957 Korean adults.

BACKGROUND: Maintaining adequate levels of sleep and physical activity (PA) as self-help for the prevention of new-onset anxiety symptoms is becoming more important. METHODS: A cohort study was performed with 134,957 adults, free of anxiety symptoms at baseline who underwent at least two comprehensive health screening examinations between 2012 and 2017. At baseline, the amount of PA was measured using the International Physical Activity Questionnaire-Short Form and sleep duration per day was assessed using a self-report questionnaire. The study's end point was new-onset anxiety symptoms, defined as a Beck Anxiety Inventory score of ≥19. RESULTS: During 361,969 person-years of follow-up, 5086 participants developed case-level anxiety. Compared with a reference (0-600 METs-min/wk), a U-shaped relationship was observed between PA and case-level anxiety. The most beneficial levels of PA for reducing incident anxiety symptoms were higher in men than women (men: 1800-3000 METs-min/wk HR, 0.88 [95% CI, 0.78-0.81], 3000-6000 METs-min/wk HR, 0.81 [95% CI, 0.70-0.93]; women: 600-1,200 METs-min/wk HR, 0.86 [95% CI, 0.76-0.98]). In comparison with a reference (<6 h), the relationship between sleep duration and case-level anxiety also had a U-shaped pattern. The optimal sleep duration for decreasing the onset of case-level anxiety was 7-8 h, regardless of sex (men: HR, 0.75 [95% CI, 0.63-0.90]; women; HR, 0.61 [95% CI, 0.54-0.70]). LIMITATIONS: PA, sleep duration, and anxiety symptoms were measured using self-report questionnaires. CONCLUSIONS: The results of this study revealed the appropriate levels of PA and total sleep time for reducing incident anxiety symptoms.

Resilience as a Protective Factor for Suicidal Ideation among Korean Workers.

OBJECTIVE: This study aimed to investigate resilience as a protective factor for suicidality among Korean workers. METHODS: Participants were workers from 26 organizations in Korea, aged 18 to 63 years, who completed a self-reported questionnaire comprising items on sociodemographic factors, job stress, resilience, and suicidality. Completed questionnaires were collected from 4,405 persons, with 4,389 valid responses. Hierarchical logistic regression analyses were performed using suicidality as the dependent variable. RESULTS: Results of the logistic regression analyses indicated that among the sociodemographic factors, older age, being female, and being single were statistically significantly associated with suicidal ideation. A high level of job stress, depressive mood, and anxiety, in addition to a short job duration, were also associated with suicidal ideation. Resilience was a significant protective factor for suicidal ideation after adjusting for all other variables. Older age and high anxiety levels were associated with having a suicide plan among participants with suicidal ideation. The association of resilience with suicide plans and suicide attempts was non-significant. CONCLUSION: In this study, we found that a high level of resilience was associated with a low incidence of suicidal ideation in Korean workers. Based on these results, we suggest the need to develop and implement interventions to improve resilience in the workplace, thereby protecting workers, especially those with a high level of work stress, from suicidal ideation.

Association between work stress and risk of suicidal ideation: A cohort study among Korean employees examining gender and age differences.

Objective The aim of this study was to identify work stress associated with the development of suicidal ideation with a focus on gender and age differences among Korean employees. Methods The data of 95 356 healthy employees aged >18 years who had undergone at least two comprehensive health examinations at Kangbuk Samsung Hospital Health Screening Center, South Korea, were analyzed. Risk of suicidal ideation was assessed using a self-reported questionnaire examining suicidal ideation during the past year. Work stress was measured using the Korean Occupational Stress Scale-Short Form. A Cox proportional hazards model was used to examine relationship between work stress and suicidal ideation. Considering gender and age differences in the association between work stress and suicidal ideation, the data were stratified by gender and age groups. Results During 289 706 person-years of follow-up, suicide ideation was identified in 3 460 participants. For male workers, high job demands and lack of reward were associated with the risk of suicidal ideation in young adults and midlife decade group. Job insecurity was associated with the risk of suicidal ideation in midlife decade and middle-aged and older adulthood. Organizational injustice was associated with the risk of suicidal ideation in middle-aged and older adulthood. Discomfort in an organizational climate was associated with the development of suicidal ideation in all age groups. For female workers, organizational injustice and discomfort in an organizational climate were associated with the risk of suicidal ideation in early adulthood. Conclusion The results suggested that certain work stressors are risk factors of suicidal ideation. Gender and age differences in components of work stress associated with suicidal ideation were also observed.

The Association between Physical Activity and Anxiety Symptoms for General Adult Populations: An Analysis of the Dose-Response Relationship.

OBJECTIVE: The aim of this study is to determine the dose-response relationship between physical activity and anxiety symptoms. METHODS: We included data of 124,434 participants who had comprehensive health-screening examinations from January 1st, 2012, to December 31st, 2016, in Kangbuk Samsung Hospital, Seoul and Suwon, South Korea. We measured the level of physical activity using the International Physical Activity Questionnaire-short form (IPAQ-SF) and estimated anxiety symptoms using the Beck Anxiety Inventory (BAI). BAI scores of 19 and above were defined as cases. Logistic regression was used to analyze the association between physical activity and BAI-defined anxiety. Furthermore, we assessed whether sex differences might affect the relationship between physical activity and BAI-defined anxiety by stratifying our data. RESULTS: Compared with the sedentary group (0-600 METs-min/week), individuals achieving 600-6,000 METs-min/wk had a significantly lower risk of BAI-defined anxiety with a U-shaped relationship in general adults. After stratifying our data by sex, we found that optimal ranges of physical activity were 600-9,000 METs-min/wk for men, but 1,200-3,000 METs-min/wk for women. CONCLUSION: We identified a U- or J-shaped association between physical activity and anxiety symptoms, suggesting an optimal dose and upper limit of physical activity for decreasing anxiety symptoms. Optimal levels and upper limits of physical activity for reducing anxiety symptoms were higher for men than for women.

Gender and age differences in the association between work stress and incident depressive symptoms among Korean employees: a cohort study.

PURPOSE: The aim of this study was to identify gender- and age-specific occupational stress associated with depressive symptoms among Korean employees. METHODS: Data of 73,014 employees aged 18 and above who had undergone comprehensive health examinations at Kangbuk Samsung Hospital Health Screening Center, South Korea, in January 2012 and who were followed up until December 2017 were collected, and 63,959 (participation rate: 87.59%, men: 50,413, women: 13,546) were finally analyzed. A Cox proportional hazards model was used to estimate the hazard ratios and 95% confidence intervals of the relationship between occupational stress and depressive symptoms. In light of gender and age differences in the association between occupational stress and depressive symptoms, interaction and stratification by gender and age groups were tested. RESULTS: During 238,630 person-years of follow-up, case-level depressive symptoms developed in 4227 participants (an incident rate of 1.8%). There were gender differences in the relationship between job stress and incident depressive symptoms. For men, high job demand, job insecurity, lack of reward, and discomfort in their organizational climate were associated with incident depressive symptoms in all age groups. Insufficient job control was associated with the development of depressive symptoms only in midlife and organizational injustice only in early adulthood. For women, the results for high job demand, organizational injustice, and discomfort in an organizational climate were associated with the onset of depressive symptoms from early adulthood to the midlife decade. CONCLUSION: The results suggest gender and age differences in the relationship between occupational stress and incident depressive symptoms.

Physical activity and the prevention of depression: A cohort study.

OBJECTIVE: This study aims to identify the optimal amount and appropriate state of physical activity for reducing incident depressive symptoms. METHOD: The data of 107,901 Korean adults who had undergone at least two annual health examinations from 2012 to 2015 were analyzed. At baseline, the amount of physical activity was measured using the International Physical Activity Questionnaire-Short Form and metabolic equivalents (METs)-min/wk., which is the amount of oxygen consumed while sitting at rest per week. In addition, one-year changes in physical activity were categorized into four groups: persistent sedentary, maintenance, relapse, and adoption groups. For the study's endpoint, new-onset depressive symptoms (score of ≥21) were considered, defined by the Center for Epidemiologic Studies Rating Scale for Depression. A Cox proportional hazards model was used to identify the optimal amount and appropriate state of physical activity for reducing incident depressive symptoms. RESULTS: Compared with sedentary status (<600 METs-min/wk), achieving 1200-3000 METs-min/wk. was associated with a lower risk of incident depressive symptoms, illustrating a U-shaped relationship. The results show that the amount of physical activity for reducing the onset of depressive symptoms was higher for men (1800-3000 METs-min/wk.: HR, 0.84 [95% CI, 0.74-0.95]) than women (1200-1800 METs-min/wk.: HR, 0.84 [95% CI, 0.71-0.99]). In terms of one-year changes in physical activity, compared to the persistent sedentary group, the maintenance group was associated with a lower risk of the development of depressive symptoms in both sexes (men: HR, 0.81 [95% CI, 0.71-0.93]; women: HR, 0.84 [95% CI, 0.75-0.94]). Women in the adoption group showed a positive effect in terms of a decrease in incident depressive symptoms (HR, 0.87 [95% CI, 0.76-0.99]). CONCLUSIONS: This study suggests an optimal amount of physical activity for reducing the onset of depressive symptoms. In addition, maintaining an appropriate level of physical activity for one year proved beneficial for decreasing incident depressive symptoms.

Metabolic syndrome and incident depressive symptoms in young and middle-aged adults: A cohort study.

BACKGROUND: Recent studies on the prospective association between metabolic syndrome (MetS) and depression have reported conflicting findings. METHODS: A cohort study was performed with 115,223 middle-aged adults, free of depression at baseline, who underwent at least 2 comprehensive exams between 2012 and 2015. MetS was assessed according to the National Cholesterol Education Program Adult Treatment Panel III. The study endpoint was new onset of depression, defined as a Center for Epidemiologic Studies-Depression Scale score ≥ 16. RESULTS: Over 253,451.6 person-years, 6,833 participants developed depression. When the participants with 0 MetS components were set as a reference, the multivariable-adjusted hazard ratio (HR, 95% confidence interval [CI]) for incident depression formed a U-shaped curve with the number of MetS components (p for trend = 0.229): 1 (1.07 [1.02-1.15]); 2 (0.92 [0.82-1.06]); 3 (0.85 [0.78-1.07]); 4 (1.16 [1.06-1.32]); and 5 MetS components (1.25 [1.10-1.54]). The presence or absence of MetS was not significant in new-onset depression. In examining potential clustering and synergistic effects of the constituent parts, waist circumference was the major driving factor of incident depression, and its relative excess risk due to interaction increased with the number of combinations. LIMITATIONS: We used a self-reported depression scale, and the follow-up period was relatively short. CONCLUSIONS: Future studies investigating the risk for incident depression should place more focus on the number of MetS abnormalities and specific MetS factors, such as waist circumference, than the presence or absence of MetS.

Brazing Characteristics and Bonding Strength of Pure Titanium Joints Brazed with Low-Melting Temperature Zi-17Ti-22Ni Filler Metal.

The brazing characteristics and bonding strengths of pure titanium joints are evaluated for joints brazed with Zr-17Ti-22Ni filler. Vacuum brazing was conducted at temperatures between the melting temperatures of the filler metals and the beta-transition temperature of pure titanium at 3 MPa of pressure for 5 min. Fracturing of the pure titanium joint brazed at 1,093 K occurred before yielding during the tensile tests owing to the presence of a serious segregation region containing harder and more brittle [Ti, Zr]2Ni intermetallic compounds. In contrast, in pure titanium joints brazed at and above 1,113 K, fracturing occurred at the base metal. The yield strengths of the samples brazed at 1,113 K-1,133 K were estimated to be in the range of 320-350 MPa and the ultimate tensile strengths likewise ranged from 350 to 380 MPa. The strength of pure titanium brazed at 1,153 K decreased rapidly. The results of this study show that the optimum temperature to ensure good performance after the brazing of pure titanium with Zr-17Ti-22Ni as a filler metal ranges from 1,113 K to 1,133 K.

Evaluation of the Hot Workability of Commercially Pure Ti Using Hot Torsion Tests.

Optimum processing conditions were obtained by evaluating the hot working behavior of commercially pure Ti using hot torsion tests. Hot torsion tests were conducted at temperatures ranging from 800 °C-1000 °C and strain rates ranging from 0.1-10 s-1. The flow curves show that the peak stress increases as the temperature decreases and the strain rate increases. The optimum processing conditions were derived by comparing the processing and activation energy maps. The microstructure was characterized based on various regions of the processing map. The activation energy for plastic deformation was obtained using the constitutive equation. The activation energy differs depending on the constituent phases.

The Relationship between Plasma Oxytocin Levels and Social Anxiety Symptoms.

OBJECTIVE: The pathophysiology of social anxiety disorder (SAD) is not yet well understood, but previous research has suggested that oxytocin is associated with social behavior and may play a role in human anxiety states and anxiety-related traits. The aim of this study was to investigate the possible relationship between social anxiety symptoms and plasma oxytocin levels. METHODS: Twenty-three male patients with SAD and 28 healthy male controls participated in this study. All participants were assessed using the Mini International Neuropsychiatric Interview (MINI) and the Liebowitz Social Anxiety Scale (LSAS). Multivariate regression analysis was performed to identify associations between plasma oxytocin levels and SAD. RESULTS: In multiple regression models, after controlling for age and years of education, we found that higher oxytocin levels were significantly associated with higher total LSAS scores (R2 =0.157, coefficient=0.145, 95% CI=-0.0005-0.291, p=0.051) and fear subscale scores (R2 =0.134, coefficient=0.083, 95% CI=0.007-0.159, p=0.034) in the SAD group. CONCLUSION: In this study, increased plasma oxytocin levels were associated with higher social anxiety symptoms among SAD patients, but not among controls. This might be because among SAD patients, higher oxytocin (OT) secretion is an insufficient compensatory attempt to reduce social anxiety symptoms.

Association between physical activity and depressive symptoms in general adult populations: An analysis of the dose-response relationship.

This study investigated the dose-response relationship between physical activity and depression. We collected data from 99,846 participants who had no medical contraindications to exercise. Using the short-form Korean version of the International Physical Activity Questionnaire, total physical activity was computed in metabolic equivalents (METs). We used the Center for Epidemiologic Studies Rating Scale for Depression to assess depressive symptoms and set a cut off score of 21. Logistic regression analyses were used to determine any relationships. To assess the effect of sex difference on the association between physical activity and depression, we stratified our data by sex. Compared with the sedentary group (0-600 METs-min/week), 1-15 times the recommended minimum physical activity was associated with a significantly lower risk of depression in all adults. The optimal range for a lower risk of depression was 2-3 times the recommended minimum. After stratifying our data by sex, we found that optimal ranges were 10-15 times the recommended minimum physical activity in men and 3-5 times in women. This study established a U-shaped dose-response relationship between physical activity and depression. The optimal range and upper threshold for anti-depression effect of physical activity were higher in men than in women.