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Abstract Objective The evidence on the relationship between remnant cholesterol (RC) and stroke remains controversial. Therefore, this study aimed to explore the relationship between RC and stroke risk in a Chinese population of middle-aged and elderly individuals. Methods The present study included 10067 Chinese subjects of middle-aged and elderly individuals. The connection between RC and incident stroke was investigated using the multivariate Cox proportional hazards regression model, several sensitivity analyses, generalized additive models, and smoothed curve fitting. Results A total of 1180 participants with stroke were recorded during the follow-up period. The multivariate Cox proportional hazards regression model identified a positive connection between RC and stroke risk (hazard ratio (HR) = 1.087, 95% confidence interval (CI): 1.001–1.180). In addition, the current study discovered a nonlinear connection between RC and incident stroke, and the point of inflection for RC was 1.78 mmol/L. The risk of stroke increased by 25.1% with each unit increase in RC level when RC was

Objective: The evidence on the relationship between remnant cholesterol (RC) and stroke remains controversial. Therefore, this study aimed to explore the relationship between RC and stroke risk in a Chinese population of middle-aged and elderly individuals. Methods: The present study included 10067 Chinese subjects of middle-aged and elderly individuals. The connection between RC and incident stroke was investigated using the multivariate Cox proportional hazards regression model, several sensitivity analyses, generalized additive models, and smoothed curve fitting. Results: A total of 1180 participants with stroke were recorded during the follow-up period. The multivariate Cox proportional hazards regression model identified a positive connection between RC and stroke risk (hazard ratio (HR) = 1.087, 95% confidence interval (CI): 1.001–1.180). In addition, the current study discovered a nonlinear connection between RC and incident stroke, and the point of inflection for RC was 1.78 mmol/L. The risk of stroke increased by 25.1% with each unit increase in RC level when RC was < 1.78 mmol/L (HR:1.251, 95%CI: 1.089–1.437, P = 0.0015). The results were not affected by sensitivity tests. Conclusion: The current study showed a positive and nonlinear connection between RC and stroke risk in a middle-aged and elderly Chinese population. These findings provided new information to help researchers better understand the relationship between RC levels and incident stroke. [ABSTRACT FROM AUTHOR]

The nonlinear relationship between the chlorophyll content of Hopea hainanensis, an endangered tree species, and image features was discussed, and the feasibility of estimating the chlorophyll content of H. hainanensis by image color and texture features was studied in this paper, providing a reference for image-based non-destructive monitoring. The canopy chlorophyll content (SPAD value) and RGB images were obtained using a 2-year-old H. hainanensis as the research object. The generalized additive model (GAM) was used to explore the nonlinear correlation between the image color and texture characteristics and the SPAD values. The SPAD values were then estimated using the multiple linear regression, GAM, random forest, and XGBoost models based on the features without multicollinearity filtered by the Lasso algorithm. Among the 22-image color and texture features, the feature with the strongest linear correlation was a correlation standard deviation, which was positively correlated, while the feature with the strongest nonlinear correlation was entropy mean, which was inverse J-shaped and negatively correlated. The Lasso algorithm effectively removed the severe collinearity among multiple image features, and the VIF values of the 15 image features retained after screening were all lower than 10. Based on the results of estimating SPAD values using multi-image color texture features, the test accuracy of the XGBoost model was highest, and the average testing R~2, MAE, and RMSE were 0.757, 2.682, and 3.242, respectively. Therefore, there are certain nonlinear correlations between SPAD values of H. hainanensis and image color and texture features. The image estimation method based on the GAM model with nonlinear interpretation ability can be used as the optimal method for estimating the chlorophyll content of H. hainanensis. [ABSTRACT FROM AUTHOR]

Abstract Objective Evidence regarding the relationship between serum triglyceride-to-high density lipoprotein cholesterol (TG/HDL-c) ratio and outcomes in acute ischemic stroke (AIS) patients is still mixed. Therefore, the present study was undertaken to explore the link between the TG/HDL-c ratio and unfavorable outcomes in patients with AIS. Methods This was a second analysis based on a cohort study. The study population was 1764 patients with AIS collected from January 2010 to December 2016 at a hospital in South Korea. We used a binary logistic regression model to assess the linear association between the TG/HDL-c ratio and unfavorable outcomes for AIS patients. A generalized additive model (GAM) and smooth curve fitting (penalized spline method) was conducted to explore the nonlinear relationship between TG/HDL-c ratio and unfavorable outcomes for AIS patients. Additionally, we compute the inflection point using a recursive algorithm and then build a two-piece binary logistic regression model on both sides of the inflection point. A log-likelihood ratio test was used to determine the most appropriate model describing the association of TG/HDL-c ratio and unfavorable outcomes in patients with AIS. Results The incidence rate of unfavorable outcomes was 28.2%, and the median TG/HDL-c ratio was 2.130. After adjusting covariates, the results of the binary logistic regression model suggested that the relationship between the TG/HDL-c ratio and the risk of unfavorable outcomes for AIS patients was not statistically significant. However, there was a nonlinear relationship between them, and the inflection point of the TG/HDL-c ratio was 3.515. On the left side of the inflection point, each 1-unit increase in the TG/HDL-c ratio was associated with a 22.6% lower risk of unfavorable outcomes (OR = 0.774, 95%CI:0.656 to 0.914, p = 0.002). On the right side of the inflection point, the effect size (OR) was 1.195 (95%CI:1.004 to1.423, p = 0.003). Conclusion There is a nonlinear relationship and threshold effect between the TG/HDL-c ratio and 3-month unfavorable outcomes in AIS patients. When the TG/HDL-c ratio is lower than 3.515, the TG/HDL-c ratio is significantly negatively related to the risk of unfavorable outcomes. When the TG/HDL-c ratio is greater than 3.515, the TG/HDL-c ratio was positively associated with the risk of unfavorable outcomes in AIS patients. This provides a reference for optimizing lipidemia intervention and promoting clinical communication in patients with AIS.

The study of seasonal variations in Chlorophyll-a (Chl.a) concentration and its influencing factors is particularly important for lake management. The study showed that there was a strong non-linear relationship between Chl.a and environmental factors in spring and autumn, whereas there was a strong linear relationship in summer and winter. Chl.a was redistributed during the ice period, and its concentration in water generally exceeded that in the ice sheet. Characteristics of the ice sheet, including thermal insulation, transparency, and nutrient migration into the water, positively impact phytoplankton growth and reproduction. Therefore, there was no significant difference between Chl.a in winter water and Chl.a in summer water. Although there were differences in the environmental factors affecting the temporal heterogeneity of Chl.a over the four seasons, conductivity (Cond.) showed a significant linear or nonlinear effect on Chl.a throughout the year, indicating its important role in regulating the growth and reproduction of phytoplankton. Environmental factors driving the spatial heterogeneity of Chl.a included the location of the water inlet channel, the distribution of Phragmites, and hydrodynamic conditions. These findings are valuable for understanding the seasonal variation of Chlorophyll-a and preventing eutrophication and algal blooms in cold and arid lakes.

Objective: Evidence regarding the relationship between serum triglyceride-to-high density lipoprotein cholesterol (TG/HDL-c) ratio and outcomes in acute ischemic stroke (AIS) patients is still mixed. Therefore, the present study was undertaken to explore the link between the TG/HDL-c ratio and unfavorable outcomes in patients with AIS.Methods: This was a second analysis based on a cohort study. The study population was 1764 patients with AIS collected from January 2010 to December 2016 at a hospital in South Korea. We used a binary logistic regression model to assess the linear association between the TG/HDL-c ratio and unfavorable outcomes for AIS patients. A generalized additive model (GAM) and smooth curve fitting (penalized spline method) was conducted to explore the nonlinear relationship between TG/HDL-c ratio and unfavorable outcomes for AIS patients. Additionally, we compute the inflection point using a recursive algorithm and then build a two-piece binary logistic regression model on both sides of the inflection point. A log-likelihood ratio test was used to determine the most appropriate model describing the association of TG/HDL-c ratio and unfavorable outcomes in patients with AIS.Results: The incidence rate of unfavorable outcomes was 28.2%, and the median TG/HDL-c ratio was 2.130. After adjusting covariates, the results of the binary logistic regression model suggested that the relationship between the TG/HDL-c ratio and the risk of unfavorable outcomes for AIS patients was not statistically significant. However, there was a nonlinear relationship between them, and the inflection point of the TG/HDL-c ratio was 3.515. On the left side of the inflection point, each 1-unit increase in the TG/HDL-c ratio was associated with a 22.6% lower risk of unfavorable outcomes (OR = 0.774, 95%CI:0.656 to 0.914, p = 0.002). On the right side of the inflection point, the effect size (OR) was 1.195 (95%CI:1.004 to1.423, p = 0.003).Conclusion: There is a nonlinear relationship and threshold effect between the TG/HDL-c ratio and 3-month unfavorable outcomes in AIS patients. When the TG/HDL-c ratio is lower than 3.515, the TG/HDL-c ratio is significantly negatively related to the risk of unfavorable outcomes. When the TG/HDL-c ratio is greater than 3.515, the TG/HDL-c ratio was positively associated with the risk of unfavorable outcomes in AIS patients. This provides a reference for optimizing lipidemia intervention and promoting clinical communication in patients with AIS. [ABSTRACT FROM AUTHOR]

Work is reported as a major source of psychological stress. Because of its role in the onset of burnout and its impact on economic and health systems, work stress (WS) has become an issue of great concern. Two categories of physical activity, namely leisure-time and moderate-to-vigorous physical activity (LTPA and MVPA), show promising evidence for reducing WS. Previous findings suggest that LTPA and MVPA allow adults to experience psychological detachment from job demands and to restore their depleted resources at work. However, doses of LTPA and MVPA associated with WS have not been established. This study aimed to address this gap using a cross-sectional, nationally representative sample of 4200 workers. Generalized additive models indicated that one hour a day, on average, spent doing an LTPA of 8.5 metabolic equivalents-hour (METs-hour) was associated with the lowest WS level (p < 0.001, Adjusted R2 = 0.04) while the optimal daily dose of MVPA was around 90 min (p < 0.001, Adjusted R2 = 0.04). A reduction in WS occurs even with low doses of physical activity, aligning with the tenet that getting some physical activity is better than none. This study's findings offer quantitative insights for guiding health policies as well as future longitudinal and experimental studies. [ABSTRACT FROM AUTHOR]

Few studies have estimated the nonlinear association of ambient temperature with the risk of influenza. We therefore applied a time-series analysis to explore the short-term effect of ambient temperature on the incidence of influenza in Wuhan, China. Daily influenza cases were collected from Hubei Provincial Center for Disease Control and Prevention (Hubei CDC) from January 1, 2014, to December 31, 2017. The meteorological and daily pollutant data was obtained from the Hubei Meteorological Service Center and National Air Quality Monitoring Stations, respectively. We used a generalized additive model (GAM) coupled with the distributed lag nonlinear model (DLNM) to explore the exposure-lag-response relationship between the short-term risk of influenza and daily average ambient temperature. Analyses were also performed to assess the extreme cold and hot temperature effects. We observed that the ambient temperature was statistically significant, and the exposure–response curve is approximately S-shaped, with a peak observed at 23.57 ℃. The single-day lag curve showed that extreme hot and cold temperatures were both significantly associated with influenza. The extreme hot temperature has an acute effect on influenza, with the most significant effect observed at lag 0–1. The extreme cold temperature has a relatively smaller effect but lasts longer, with the effect exerted continuously during a lag of 2–4 days. Our study found significant nonlinear and delayed associations between ambient temperature and the incidence of influenza. Our finding contributes to the establishment of an early warning system for airborne infectious diseases. [ABSTRACT FROM AUTHOR]

• The concentration of Chl.a in winter lakes can reach the same level as in summer. • Freezing drives the redistribution of Chl.a between ice and water. • Freezing helps the phytoplankton survive the winter. • Different environmental factors drive the variation of Chl.a in different seasons. The study of seasonal variations in Chlorophyll-a (Chl.a) concentration and its influencing factors is particularly important for lake management. The study showed that there was a strong non-linear relationship between Chl.a and environmental factors in spring and autumn, whereas there was a strong linear relationship in summer and winter. Chl.a was redistributed during the ice period, and its concentration in water generally exceeded that in the ice sheet. Characteristics of the ice sheet, including thermal insulation, transparency, and nutrient migration into the water, positively impact phytoplankton growth and reproduction. Therefore, there was no significant difference between Chl.a in winter water and Chl.a in summer water. Although there were differences in the environmental factors affecting the temporal heterogeneity of Chl.a over the four seasons, conductivity (Cond.) showed a significant linear or nonlinear effect on Chl.a throughout the year, indicating its important role in regulating the growth and reproduction of phytoplankton. Environmental factors driving the spatial heterogeneity of Chl.a included the location of the water inlet channel, the distribution of Phragmites, and hydrodynamic conditions. These findings are valuable for understanding the seasonal variation of Chlorophyll-a and preventing eutrophication and algal blooms in cold and arid lakes. [ABSTRACT FROM AUTHOR]