Molecular insight into how the position of an abasic site modifies DNA duplex stability and dynamics.

Local perturbations to DNA base-pairing stability from lesions and chemical modifications can alter the stability and dynamics of an entire oligonucleotide. End effects may cause the position of a disruption within a short duplex to influence duplex stability and structural dynamics, yet this aspect of nucleic acid modifications is often overlooked. We investigate how the position of an abasic site (AP site) impacts the stability and dynamics of short DNA duplexes. Using a combination of steady-state and time-resolved spectroscopy and molecular dynamics simulations, we unravel an interplay between AP-site position and nucleobase sequence that controls energetic and dynamic disruption to the duplex. The duplex is disrupted into two segments by an entropic barrier for base-pairing on each side of the AP site. The barrier induces fraying of the short segment when an AP site is near the termini. Shifting the AP site inward promotes a transition from short-segment fraying to fully encompassing the barrier into the thermodynamics of hybridization, leading to further destabilization of the duplex. Nucleobase sequence determines the length scale for this transition by tuning the barrier height and base-pair stability of the short segment, and certain sequences enable out-of-register base-pairing to minimize the barrier height.

Association between long working hours and engagement in preventive healthcare services in Korean workers: Findings from the Korean National Health and Nutrition Examination Survey.

BACKGROUND: Engagement in preventive healthcare services is crucial for preventing diseases. We explored how working hours are associated with engagement in preventive healthcare services, with a focus on gender differences. METHODS: This cross-sectional study used data from the 2007-2012 Korean National Health and Nutrition Examination Survey. The dependent variable was engagement in each of the five preventive healthcare services (health check-ups, influenza vaccination, and stomach, breast, and cervical cancer screenings). We estimated the prevalence ratios (PRs) and 95% confidence intervals (CIs) using robust Poisson regression. RESULTS: The study analyzed 19,819 workers (9119 women). The adjusted PRs (95% CI) of the association between working ≥55 h per week and engagement in preventive healthcare services among men were 0.95 (0.90-1.00) for health check-ups, 0.86 (0.77-0.96) for influenza vaccination, and 0.95 (0.87-1.03) for stomach cancer screening compared to working 35-40 h per week. Among women, the adjusted PRs (95% CI) of the association between working ≥55 h per week and engagement in preventive healthcare services were 0.84 (0.78-0.91) for health check-ups, 0.82 (0.73-0.92) for influenza vaccination, and 0.88 (0.80-0.97) for stomach, 0.85 (0.78-0.94) for breast, and 0.82 (0.74-0.91) for cervical cancer screenings. CONCLUSION: Long working hours were negatively associated with engagement in preventive healthcare services, and the association was pronounced among female workers. Efforts to promote preventive healthcare participation among individuals with long working hours are necessary, and it is essential to consider the unique vulnerabilities of women when developing such policies.

Association between long working hours and diet quality and patterns: A latent profile analysis of a nationally representative sample of Korean workers.

BACKGROUND: Long working hours are associated with cardiovascular and metabolic diseases. This study investigated the relationship between the working hours and dietary qualities and patterns in Korean workers. METHODS: Data from 24,523 workers were extracted from the Korea National Health and Nutrition Examination Survey, 2013-2021. The Korean Healthy Eating Index (KHEI), which ranges from 0 to 100, with a higher score indicating greater adherence to Korean dietary guidelines and superior dietary quality, was used for dietary assessment. We identified dietary patterns and classified workers using latent profile analysis. Logistic regressions were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Five distinct dietary patterns emerged: healthy diet (24.8%), low-vegetable diet (14.0%), average diet (7.8%), low-fruit diet (31.4%), and poor diet (22.0%). The mean KHEI score was 60.8, with the highest score observed in the healthy diet pattern (71.3) and the lowest, in the poor diet pattern (50.0). Compared with working 35-40 h/week, working ≥55 h/week was negatively associated with KHEI scores (ß: -1.08; 95% CI: -1.67, -0.49). Those working ≥55 h/week were less likely to have a healthy diet pattern (OR: 0.81; 95% CI: 0.72, 0.91) and more likely to have a low-fruit diet (OR: 1.36; 95% CI: 1.20, 1.55) or poor diet pattern (OR: 1.23; 95% CI: 1.05, 1.43) compared with those working 35-40 h/week. CONCLUSION: Long working hours are associated with undesirable dietary quality and patterns. Policy interventions aimed at enhancing dietary quality are needed to alleviate the health burdens associated with long working hours.

A multiplex real-time RT-qPCR assay for simultaneous detection of porcine epidemic diarrhea virus, porcine deltacoronavirus, and swine acute diarrhea syndrome coronavirus.

Porcine epidemic diarrhea virus (PEDV), porcine deltacoronavirus (PDCoV), and swine acute diarrhea syndrome coronavirus (SADS-CoV) cause intestinal diseases with similar manifestations in suckling piglets. In this study, we developed a multiplex real-time PCR for differential diagnosis of PEDV, PDCoV, and SADS-CoV. The assay demonstrated high specificity with a detection limit of 5 copies/µl for each virus. The assay specifically detected PEDV, PDCoV, and SADS-CoV and excluded all other swine pathogens circulating in pigs. Furthermore, the assay exhibited satisfactory performance in analyzing clinical samples. The data indicate that the newly developed multiplex real-time PCR method can be applied for differential diagnosis of porcine enteric coronaviruses.

Neighborhood Safety Concerns and the Onset of Depressive Symptoms Among Women: A Population-based Prospective Cohort Study in South Korea.

Neighborhood safety is crucial for the well-being of residents; however, longitudinal evidence is scarce. This study explored the association between neighborhood safety concerns and depressive symptoms among women. A nationally representative sample of 10,008 women was surveyed in 2016. Six dimensions of neighborhood safety concerns were assessed: crime, food, safety at night, traffic accidents, building and facility, and general safety. The total score for neighborhood safety concerns ranged from 6 to 24, with higher scores indicating greater concerns. Depressive symptoms were assessed using the 10-item version of the Center for Epidemiologic Studies Depression. For cross-sectional analyses, we explored how neighborhood safety concerns were associated with concurrent depressive symptoms at baseline. For the longitudinal analyses, we explored how they were associated with depressive symptom onset at the 2-year follow-up (2018) among women without depressive symptoms at baseline (n = 7,643). Logistic regressions were employed. The mean (standard deviation [SD]) of the neighborhood safety concern score was 12.7 (3.3). In the cross-sectional analysis, a 1-SD increase in neighborhood safety concern score was associated with 1.23-fold (95% CI: 1.13-1.35) increase in the odds of concurrent depressive symptoms at the baseline year. In the longitudinal analysis, a 1-SD increase in neighborhood safety concern score was associated with 1.15-fold (95% CI: 1.03-1.29) increase in the odds of experiencing the onset of depressive symptoms at the follow-up year. This study suggests that neighborhood safety concerns are risk factors for the development of depressive symptoms of female residents. Policy efforts are necessary to ensure community safety.

Interaction between old age and precarious employment on poor mental well-being in workers: Evidence from a nationally representative sample in Korea.

OBJECTIVE: This study examined the relationship between precarious employment (PE) and mental well-being, focusing on age-specific interactions. METHODS: Nationally representative Korean workers (N = 29,961) were surveyed between 2020 and 2021 to collect data on multidimensional PE (categorized as low, moderate, or high) and the WHO-5 well-being index. Workers' ages were classified as young (<35 years), middle-aged (35-54 years), and older (≥55 years). Logistic regression was performed to estimate the odds ratios (ORs) and 95% confidence intervals (CIs). The interaction between PE and age on well-being was examined by including interaction terms in the regression models. RESULTS: The prevalence of poor well-being was 25%, 29%, and 39% for low, moderate, and high precariousness, respectively, whereas it was 26%, 30%, and 39% for young, middle-aged, and older workers, respectively. In the overall sample, the OR (95% CI) of the association between PE and poor well-being was 1.24 (1.17-1.32) for moderate and 1.54 (1.43-1.65) for high precariousness, compared with low precariousness. There was a significant interaction between old age and PE on the odds of poor well-being. Compared with young workers with low PE, middle-aged workers with high PE (OR: 1.85, 95% CI: 1.62-2.10) and older workers with high PE (OR: 2.10, 95% CI: 1.83-2.40) exhibited increased odds of having poor mental well-being. CONCLUSION: PE serves as a social determinant of older workers' psychological well-being. Policy interventions are required to protect older workers' psychological well-being.

Long working hours, work-life imbalance, and poor mental health: a cross-sectional mediation analysis based on the sixth Korean Working Conditions Survey, 2020-2021.

Background There has been growing concern about the negative mental health impact of long working hours and overwork. Our study examined how work-life imbalance (WLI) could be a mediator between working hours and poor mental well-being.Methods We included 34,968 individuals from a nationwide cross-sectional survey in Korea. Self-reported working hours per week was collected, and mental health was assessed by the WHO-5 Well-Being Index. Counterfactual-based mediation models were employed to disentangle the total effects into a direct effect (work hour - poor mental health) and an indirect effect (work hour - WLI - poor mental health).Results Out of 34,968 participants, 52.6% worked 35-40 h/week, 20.0% worked 41-48 h/week, 11.7% worked 49-54 h/week, and 15.6% worked ≥55 h/week. The odds ratios (ORs) of the total impact of working hours on poor mental health were 1.08 (95% CI: 1.01-1.16) for 41-48 h/week, 1.28 (1.17-1.39) for 49-54 h/week, and 1.60 (1.48-1.74) for ≥55 h/week in comparison to 35-40 h/week. The ORs of the indirect effects were 1.04 (1.03-1.05) for 41-48 h/week, 1.08 (1.07-1.09) for 49-54 h/week, and 1.14 (1.12-1.16) for ≥55 h/week, accounting for 51%, 31%, and 28% of the total effects.Conclusion: Our findings suggest that WLI can partially mediate the association of long working hours with mental health deterioration. Policy efforts are required to mitigate the adverse mental health effects of overwork.

Association between temporary employment and current smoking and change in smoking behaviors: A prospective cohort study from South Korea (2009-2018).

Background Previous studies have suggested that employment insecurity is associated with adverse health outcomes. We explored the association between temporary employment and smoking behaviors.Methods We analyzed 11,795 workers (51,867 observations) from the Korea Health Panel Study (2009-2018). Employment types were categorized as regular, fixed-term, or daily, based on the duration of labor contract. The outcomes were current smoking status and changes in smoking behavior (initiation or cessation) in the following year. Generalized estimating equations were used to estimate odds ratio (OR) and 95% confidence interval (CI).Results The proportions of fixed-term and daily workers were 41.2% and 16.4% for women and 23.6% and 12.4% for men, respectively. Temporary employment was associated with increased odds of current smoking, while also demonstrating prospective associations with changes in smoking behaviors. For instance, in prospective analyses, male workers with fixed-term and daily employments were associated with a decreased likelihood of smoking cessation (OR:0.77; 95% CI:0.65-0.91 for fixed-term employment and OR:0.66; 95% CI:0.52-0.83 for daily employment) in the following year compared to those with regular employment. Moreover, those experiencing consecutive temporary employment was most inversely associated with smoking cessation in both men (OR:0.56; 95% CI:0.44-0.71) and women (OR:0.37; 95% CI:0.16-0.85) compared to those experiencing consecutive regular employment. However, no clear association between temporary employment and smoking initiation was observed in both men and women.Conclusions Temporary employment is directly associated with current smoking and inversely associated with smoking cessation. Policies are needed to improve job insecurity among temporary employees.

Long working hours and preventive oral health behaviors: a nationwide study in Korea (2007-2021).

BACKGROUND: This study explored the association between working hours and preventive oral health behaviors. METHODS: In total, 48,599 workers (22,992 females) were included from the Korea National Health and Nutrition Examination Survey (2007-2021). Weekly working hours were self-reported. The following three preventive oral health behaviors were set as outcomes: participation in annual dental check-ups; adherence to the recommended toothbrushing frequency (≥twice a day); and use of interdental cleaning devices. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) using logistic regression. RESULTS: In male workers, the adjusted OR (95% CI) of the association between working ≥55 h/week and each outcome was 0.84 (0.77-0.92) for dental check-ups, 0.82 (0.72-0.94) for toothbrushing ≥twice a day, and 0.83 (0.76-0.92) for utilization of interdental cleaning device when compared to 35-40 h/week. In female workers, the adjusted OR (95% CI) of the association between working ≥55 h/week and each outcome was 0.79 (0.70-0.89) for dental check-ups, 0.88 (0.70-1.11) for toothbrushing ≥twice a day, and 0.80 (0.71-0.90) for utilization of interdental cleaning device when compared to 35-40 h/week. Additionally, low socio-economic status, such as low educational attainment, low income level, and blue-collar occupations, were major risk factors associated with non-adherence to preventive oral health behaviors in both male and female workers. CONCLUSIONS: Our study suggests that individuals who work long hours are more likely to exhibit undesirable oral health behaviors.

Comparison of the Influence of Dual-Task Activities on Prefrontal Activation and Gait Variables in Older Adults with Mild Cognitive Impairment during Straight and Curved Walking.

Background and Objectives: Mild cognitive impairment (MCI) is an early stage of dementia in which everyday tasks can be maintained; however, notable challenges may occur in memory, focus, and problem-solving skills. Therefore, motor-cognitive dual-task training is warranted to prevent cognitive decline and improve cognition in aging populations. This study aimed to determine the influence of such dual-task activities during straight and curved walking on the activities of the prefrontal cortex and associated gait variables in older adults with MCI. Materials and Methods: Twenty-seven older adults aged ≥65 years and identified as having MCI based on their scores (18-23) on the Korean Mini-Mental State Examination were enrolled. The participants performed four task scenarios in random order: walking straight, walking straight with a cognitive task, walking curved, and walking curved with a cognitive task. The activation of the prefrontal cortex, which is manifested by a change in the level of oxyhemoglobin, was measured using functional near-infrared spectroscopy. The gait speed and step count were recorded during the task performance. Results: Significant differences were observed in prefrontal cortex activation and gait variables (p < 0.05). Specifically, a substantial increase was observed in prefrontal cortex activation during a dual task compared with that during a resting-state (p < 0.013). Additionally, significant variations were noted in the gait speed and step count (p < 0.05). Conclusions: This study directly demonstrates the impact of motor-cognitive dual-task training on prefrontal cortex activation in older adults with MCI, suggesting the importance of including such interventions in enhancing cognitive function.

Thermodynamics and kinetics of DNA and RNA dinucleotide hybridization to gaps and overhangs.

Hybridization of short nucleic acid segments (<4 nt) to single-strand templates occurs as a critical intermediate in processes such as nonenzymatic nucleic acid replication and toehold-mediated strand displacement. These templates often contain adjacent duplex segments that stabilize base pairing with single-strand gaps or overhangs, but the thermodynamics and kinetics of hybridization in such contexts are poorly understood because of the experimental challenges of probing weak binding and rapid structural dynamics. Here we develop an approach to directly measure the thermodynamics and kinetics of DNA and RNA dinucleotide dehybridization using steady-state and temperature-jump infrared spectroscopy. Our results suggest that dinucleotide binding is stabilized through coaxial stacking interactions with the adjacent duplex segments as well as from potential noncanonical base-pairing configurations and structural dynamics of gap and overhang templates revealed using molecular dynamics simulations. We measure timescales for dissociation ranging from 0.2-40 µs depending on the template and temperature. Dinucleotide hybridization and dehybridization involve a significant free energy barrier with characteristics resembling that of canonical oligonucleotides. Together, our work provides an initial step for predicting the stability and kinetics of hybridization between short nucleic acid segments and various templates.

Ultrafast Energy Transfer Involving the Red Chlorophylls of Cyanobacterial Photosystem I Probed through Two-Dimensional Electronic Spectroscopy.

Photosystem I (PSI) is a naturally occurring light-harvesting complex that drives oxygenic photosynthesis through a series of photoinitiated transmembrane electron transfer reactions that occur with a high quantum efficiency. Understanding the mechanism by which this process occurs is fundamental to understanding the near-unity quantum efficiency of PSI and in turn could lead to further insight into PSI-based technologies for solar energy conversion. In this article, we have applied two-dimensional electronic spectroscopy to PSI complexes isolated from two different cyanobacterial strains to gain further insight into the ultrafast energy transfer in PSI. The PSI complexes studied differ in the number and absorption of the red chlorophylls, chlorophylls that lie to lower energies than the reaction center. By applying a global analysis to the 2D electronic spectra of the PSI complexes we extract 2D decay associated spectra (2D-DAS). Through analysis of the 2D-DAS we observe a 50 fs relaxation among the bulk antenna chlorophylls in addition to two pathways of energy equilibration involving the red chlorophylls: a fast 200 fs equilibration followed by a 2-4 ps equilibration. As demonstrated with a model system, the λ1, λ3 coordinates of the cross-peaks in the 2D-DAS spectra indicate that the two equilibration pathways involve different chlorophyll molecules.

Ultrafast Solvation Dynamics and Vibrational Coherences of Halogenated Boron-Dipyrromethene Derivatives Revealed through Two-Dimensional Electronic Spectroscopy.

Boron-dipyrromethene (BODIPY) chromophores have a wide range of applications, spanning areas from biological imaging to solar energy conversion. Understanding the ultrafast dynamics of electronically excited BODIPY chromophores could lead to further advances in these areas. In this work, we characterize and compare the ultrafast dynamics of halogenated BODIPY chromophores through applying two-dimensional electronic spectroscopy (2DES). Through our studies, we demonstrate a new data analysis procedure for extracting the dynamic Stokes shift from 2DES spectra revealing an ultrafast solvent relaxation. In addition, we extract the frequency of the vibrational modes that are strongly coupled to the electronic excitation, and compare the results of structurally different BODIPY chromophores. We interpret our results with the aid of DFT calculations, finding that structural modifications lead to changes in the frequency, identity, and magnitude of Franck-Condon active vibrational modes. We attribute these changes to differences in the electron density of the electronic states of the structurally different BODIPY chromophores.

Single layer retarder with negative dispersion of birefringence and wide field-of-view.

A single layer retarder possessing negative dispersion (ND) of birefringence as well as wide field-of-view (FOV) was long-term objective in optical science. We synthesized new guest reactive monomers with x-shape and mixed them with the host smectic reactive mesogen. The host-guest molecules formed two dimensionally self-organized nanostructure and showed both the ND of birefringence and wide FOV properties. We simulated the antireflection property of a circular polarizer using the optical properties of the retarder. The average reflectance of the retarder was 0.52% which was much smaller than that of the commercial single layer ND retarder 1.83%.

Association between long working hours and the development of suicidal ideation among female workers: An 8-year population-based study using the Korean Longitudinal Survey of Women & Family (2012-2020).

Long working hours and overwork have recently emerged as pressing public health concerns. We explored the association between long working hours and suicidal ideation in female workers. A total of 8017 women (24,331 observations) from the fourth to eighth waves of the Korean Longitudinal Survey of Women and Families (2012-2020) were analyzed. To address the repeated measurements within each participant, we employed a generalized estimating equation to estimate the odds ratio (OR) and 95% confidence intervals (CIs). The prevalence of suicidal ideation was 1.9% for those working 35-40 h/week and 4.4% for those working ≥55 h/week. Compared to individuals working 35-40 h/week, those working ≥55 h/week were more likely to experience concurrent suicidal ideation (OR [95% CI]:1.85 [1.43-2.39]). The OR (95% CI) of the association between long working hours and onset of suicidal ideation in the subsequent wave was 1.69 (1.20-2.38) for ≥55 h/week. In subgroup analysis, this association was pronounced among workers with low-income levels (OR [95% CI]: 1.97 [1.29-3.02]) and blue-collar occupations (OR [95% CI]: 2.27 [1.41-3.66]). Policy efforts are required to protect the mental health of female workers exposed to long working hours.

Association of precarious employment with depressive symptoms and suicidal ideation among female workers: Findings from a nationwide longitudinal study in Korea.

BACKGROUND: In this study, we examined the relationship of precarious employment (PE) with depressive symptoms and suicidal ideation among Korean women. METHODS: We included a nationwide sample of 4162 women drawn from the Korean Longitudinal Study of Women and Families, comprising 7566 observations. PE was assessed using three dimensions: employment insecurity, income inadequacy, and lack of rights and protection. Depressive symptoms were assessed using the 10-item version of the Center for Epidemiological Studies Depression Scale. Generalized estimating equations were used to estimate the association between each element of PE and the depressive symptoms and suicidal ideation over a two-year follow-up period, represented as odds ratios (ORs) and confidence intervals (CIs). RESULTS: The overall prevalence rates of depressive symptoms and suicidal ideation were 11.8 % and 1.9 %, respectively. Compared with permanent employment, fixed-term employment (OR [95 % CI]:1.29 [1.00-1.67]) or daily employment (OR [95 % CI]:1.53 [1.26-1.99]) was associated with the depressive symptoms at the follow-up. Additionally, lack of social benefits (OR [95 % CI]:1.40 [1.09-1.79]) and high perceived vulnerability (OR [95 % CI]:1.27 [1.08-1.49]) were associated with the depressive symptoms at the follow-up. Additionally, daily employment was associated with the suicidal ideation at the follow-up (OR [95 % CI]:1.94 [1.02-3.68]) and high perceived vulnerability was marginally associated with an increased suicidal ideation risk (OR [95 % CI]:1.49 [0.98-2.29]). LIMITATION: Causal effect of PE could not be asserted due to the observational nature of this study. CONCLUSIONS: PE is a social determinant of women's mental health and policy interventions are required to improve their employment conditions.

Association of low-quality employment with the development of suicidal thought and suicide planning in workers: A longitudinal study in Korea.

BACKGROUND: Employment quality stands as a crucial social determinant impacting workers' health. In this study, we investigate the association between low-quality employment and the emergence of suicidal thoughts and planning. METHODS: We analyzed data from 7,797 Korean workers, amounting to 30,945 observations. Low-quality employment was characterized by three primary dimensions: employment insecurity, income inadequacy, and a lack of rights and protection. We employed a generalized estimating equation to probe the link between experiencing low-quality employment and the occurrence of suicidal thought and planning within the subsequent year. Odds ratios (OR) and 95% confidence intervals (CI) were estimated. RESULTS: The overall incidence rates for suicidal thought and planning were 1.5% and 0.2%, respectively, across the observations. Workers with the lowest employment quality demonstrated higher propensities to develop both suicidal thought (OR: 2.05, 95% CI: 1.37-3.06) and planning (OR: 3.39, 95% CI: 1.08-10.64) at the following year, compared with workers with the highest overall employment quality. Specifically, daily employment exhibited associations with the onset of suicidal thought (OR: 1.64, 95% CI: 1.17-2.31) and suicide planning (OR: 3.49, 95% CI: 1.54-7.92) when compared to permanent employment. Additionally, individuals in the lowest monthly wage quartile displayed a heightened likelihood of developing suicidal thought (OR: 2.09, CI: 1.36-3.23) compared with those in the highest quartile. CONCLUSION: Our findings suggest that low-quality employment is associated with the onset of suicidal thought and suicide planning at follow-up. Therefore, employment quality is a critical social determinant of workers' mental health.

Precarious employment and the onset of depressive symptoms and problematic alcohol use in middle-aged or older workers: A Korean longitudinal study (2006-2022).

Although precarious employment (PE) has emerged as a growing public health concern, research on older adults is scarce. This study explored the associations between PE and the onset of depressive symptoms and problematic alcohol use among middle-aged and older workers. A total of 2536 Korean waged workers aged ≥45 years contributed 8486 observations from 2006 to 2022. PE was defined as a multidimensional construct that includes employment insecurity, income inadequacy, and a lack of worker rights and protection. Depressive symptoms and problematic alcohol use were assessed using the Center for Epidemiological Studies Depression Scale and the CAGE questionnaire. Generalized estimating equations were employed to determine the association of PE with depressive symptoms and problematic alcohol use after the two-year follow-up. Risk ratios (RR) and 95% confidence intervals (CI) were estimated. Women, individuals with older age and low educational background, and blue-collar workers were more likely to belong to the high PE group. For individual indicators of PE, daily employment (RR: 1.26, 95% CI: 1.05-1.53), the lowest wage quartile (RR: 1.32, 95% CI: 1.01-1.72), and lack of trade union (RR: 1.55, 95% CI: 1.10-2.17) were positively associated with depressive symptom onset in the follow-up. Compared with the group with the lowest overall PE, the group with the highest PE exhibited increased risks of experiencing the onset of depressive symptoms (RR: 1.62, 95% CI: 1.27-2.08) and problematic alcohol use (RR: 2.45, 95% CI: 1.16-5.17) in the follow-up. This study suggests that PE is a major social determinant of older workers' mental health.