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In this study, numerical simulations of centrifugal compressors are carried out using ANSYS-CFX software. The focus lies in investigating the impact of the inlet tip-clearance (ITC) on the characteristics of the internal complex flow and the aerodynamic performance of centrifugal compressors. Specifically, the paper mainly emphasizes the influence of ITC on the polytropic efficiency and total pressure ratio of a centrifugal compressor, as well as the variations in velocity and pressure at the blade tip, the spatiotemporal evolution of the tip-leakage vortex (TLV), and fluctuations in pressure and velocity downstream of the passage near the blade surface. Analysis of tip-leakage flow (TLF) and TLV motion patterns at rated operating conditions reveals the spatiotemporal evolution within one revolution. Results from Fast Fourier Transform (FFT) spectrum analysis indicate that the TLV motion pattern may be affected by the ITC size. The fluid flow resistance and backflow in the blade tip region are gradually reduced, the flow field stability is effectively enhanced, and the reflux vortex at the volute outlet is eliminated, thereby the working range of the centrifugal compressor is effectively extended by decreasing the ITC. The aerodynamic performance of the centrifugal compressor is effectively increased in the range of the medium and high flow rates by decreasing ITC. Additionally, it is observed that pressure, velocity, and load in the blade tip region do not exhibit a linear relationship with ITC, resulting in a nonlinear change in aerodynamic performance concerning ITC. Pressure and velocity spectrum analysis suggests that the effect of TLF is stronger at the top of the flow passage compared to the middle. Moreover, with the increase of ITC, the effect of TLF decreases at the middle and top of the pressure side (PS) while increasing at the bottom of PS and the suction side (SS). [ABSTRACT FROM AUTHOR]

In the age of stock planning, urban vitality is a key indication of a city's health and vitality. Using the central city of Tianjin as an example, the study uses multi-source data, such as Weibo check-ins, points of interest, etc., to quantify urban vitality. The Light GBM-SHAP model is chosen to measure the non-linear effects of each indicator on urban vitality in four dimensions: crowd vitality, economic vitality, facility vitality, and environmental vitality. The study also applies spatial visualization and spatial statistical analysis to analyze the vitality of the central city of Tianjin in terms of time and space scales. The findings indicate that: (1) There is clear temporal and geographical variation in the vitality distribution in Tianjin's core urban region. Over time, spring, particularly April, is marked by a surge of vitality brought on by the tourist season and holiday effects; there is a double-peak time in the morning and evening, and the nighttime vitality is particularly strong; and, in terms of space, urban vitality tends to decline from the Heping District outward. (2) Public facility density, living facility density, and building density are the three indicators that most strongly influence urban vitality; each indication has a negligible impact on the temporal dimension of urban vitality. (3) The indicators in Tianjin's core urban region have a substantial impact on urban vitality. Their threshold effect and non-linear influence are evident, and managing the indicators within a suitable range may effectively promote urban vitality. The study's findings might serve as a foundation for Tianjin's core city's urban planning and design. [ABSTRACT FROM AUTHOR]

We extend the growth at risk (GaR) of Adrian et al. (2019) by considering the nonlinear nexus between macro-financial environment indexes and economic growth. In this extension, we use the threshold quantile regression model to investigate the nonlinear impact of five constructed macro-financial environment indexes on economic growth and measure China's GaR from 2021Q1 to 2021Q4. The empirical results show that the threshold effect does exist. Incorporating this nonlinear relationship significantly improves the accuracy of China's GaR measure in terms of smaller prediction loss. [ABSTRACT FROM AUTHOR]

Patients with atrial fibrillation (AF) are linked to an increased risk of cognitive dysfunction, and serum uric acid levels play an important factor in cognitive dysfunction. However, the optimal serum uric acid level in patients with AF remains unclear. Therefore, we aimed to explore the relationship between serum uric acid and cognitive dysfunction. 583 patients were conducted in the Affiliated Hospital of Jining Medical University. Cognitive dysfunction was assessed by the Montreal Cognitive Assessment (MoCA). The relationship between serum uric acid levels and the risk of cognitive dysfunction in patients with AF was analyzed using the smoothing spline fitting model and threshold analysis. The average serum uric acid level was (383.26 ± 110.11) μmol/L, and the incidence of cognitive dysfunction was 79.76%. There was a non‐linear relationship between serum uric acid levels and the risk of cognitive dysfunction in patients with AF, and the inflection point was 352 μmol/L. At the left of the inflection point, the relationship was significant (OR = 1.02, 95% CI = 1.00–1.04). At the right of the inflection point, there was no statistical difference (p = 0.101). When serum uric acid levels are less than 352 μmol/L, the risk of cognitive dysfunction increases by 2% for each unit increase in serum uric acid levels in patients with AF. The study provides evidence for the treatment of serum uric acid levels in patients with AF. [ABSTRACT FROM AUTHOR]

Remnant cholesterol (RC) is closely related to metabolic diseases. Our study aims to explore the relationship between RC and hyperuricemia. This cross-sectional study included 14 568 adults aged 20 years or older from the National Health and Nutrition Examination Survey (NHANES) conducted between 2007 and 2018 in the United States. RC is calculated by subtracting high-density lipoprotein cholesterol (HDL-c) and low-density lipoprotein cholesterol (LDL-c) from total cholesterol (TC). Hyperuricemia is defined by serum uric acid (SUA) levels≥7 mg/dl in men and≥6 mg/dl in women. The independent association between RC and hyperuricemia was evaluated. As the quartile range of RC levels increases, the prevalence of hyperuricemia also rises (7.84% vs. 13.71% vs. 18.61% vs. 26.24%, p<0.001). After adjusting for confounding factors, the fourth quartile of RC was associated with an increased risk of hyperuricemia compared with the first quartile (OR=2.942, 95% CI 2.473–3.502, p<0.001). Receiver Operating Characteristic (ROC) analysis shows that RC outperforms other single lipid indices in hyperuricemia. Further Restricted Cubic Splines (RCS) analysis suggests a nonlinear relationship between RC levels and hyperuricemia. Elevated RC levels were found to be linked to hyperuricemia. Further studies on RC hold promise for both preventing and addressing hyperuricemia. [ABSTRACT FROM AUTHOR]

Key message: We propose an improved exponential equation for the nonlinear dependence of cell measurements on the seasonal cell production in conifer wood. These changes shall simplify the model towards ease in understanding, interpretation and analysis. With methodological development, quantitative parameters of wood cellular structure have featured as dendroclimatic indicators in various studies. But to disentangle climatic impacts in different wood anatomical characteristics, relationships between them have to be described quantitatively and extricated. This study investigates exponential description of the non-linear dependences of conifer wood cell measurements on their seasonal production in cambial zone. Improvement to the equation of exponential model was suggested, simplifying the interpretation and analysis and providing biological meaning to all numerical parameters of the model. This new equation was demonstrated for 630 tree rings from 20 to 40-year-old trees of Siberian spruce (Picea obovata Ledeb.) in Siberia, collected at the experimental plantation, as well as for its subsets from plots of various planting density, demonstrating plausible value of the new proposed numerical parameter of model and dependence of the other parameter on the stand density, probably based on the tree height. Limitation for successful fitting of this exponential model was demonstrated, based on representativity of wide and narrow rings within sample; we proposed possible way to overcome it in certain cases. [ABSTRACT FROM AUTHOR]

More efficient use of renewable energy to reduce carbon emission requires a more comprehensive understanding of the impact of renewable energy on carbon emissions. To this end, this work investigates the linear and nonlinear relationship between renewable energy consumption and carbon emissions in 130 countries from the new perspective of resource capital factors (total natural resources rents) and human capital (human capital index). The results are given that from a global perspective, the increase in the proportion of renewable energy consumption can accelerate the reduction of per capita carbon emissions before reaching a particular threshold value of total natural resources rents. When a specific natural threshold value is reached, the increase in the proportion of renewable energy consumption will reduce the rate of per capita carbon emissions. Another interesting finding is that the greater the human factor, the lower the reduction rate of per capita carbon dioxide emissions. To explain the above phenomenon, all countries are divided into four different income levels for further heterogeneity research. When the threshold variables are different, the impact on carbon emissions in various income countries is heterogeneous, which is further analyzed in the article. Furthermore, a meaningful discovery shows that whether the threshold variable is natural or human factor, low-income countries benefit the most from the carbon reduction effect brought by the increase in the proportion of renewable energy consumption, followed by lower-middle income and upper-middle income countries, and the lowest is higher-income countries. [ABSTRACT FROM AUTHOR]

The paper analyzes the relationship between urbanization rates, the growing reliance on renewable electricity production, and CO2 emissions per capita. It further examines the economic impact of these urbanization and renewable electricity production variables on GDP per capita using threshold regression and annual data from Jordan covering the period from 1990 to 2022. The objective is to determine whether Jordan can reduce CO2 emissions despite high urbanization rates by increasing the share of renewable energy in electricity production. The fundamental assumption is that the relationship between CO2 emissions and urbanization rates varies according to the share of renewable energy production. Results from the estimated threshold regression model indicate a decline in CO2 emissions per capita during the period from 2004 to 2018, when urbanization rates ranged between 0.78 and 0.91. During this time, the compound growth rate of renewable energy share in electricity production was 24% in regime 2 (2004–2018). In contrast, CO2 emissions per capita increased both before and after this period, suggesting a nonlinear relationship between urbanization rates and CO2 emissions. This nonlinearity implies that Jordan can manage the conflicting goals of the Sustainable Development Goals (SDGs)—sustainable urbanization and low CO2 emissions—by enhancing the share of renewables in electricity production. Additionally, the results demonstrate a positive effect of urbanization rates and renewable energy shares on economic growth. [ABSTRACT FROM AUTHOR]

The arrangement and design of urban streets have a profound impact on the thermal conditions within cities, including the mitigation of excessive street land surface temperatures (LSTs). However, previous research has mainly addressed the linear relationships between the physical spatial elements of streets and LST. There has been limited exploration of potential nonlinear relationships and the influence of population density variations. This study explores multi-dimensional street composition indicators obtained from street-view imagery and applies generalized additive models (GAMs) and geographically weighted regression (GWR) to evaluate the indicators' impact on LST in areas with various population densities. The results indicate the following: (1) The six indicators—green space index (GSI), tree canopy index (TCI), sky open index (SOI), spatial enclosure index (SEI), road width index (RWI), and street walking index (SWI)—all have significant nonlinear effects on summer daytime LST. (2) Among all categories, the GSI negatively affects LST. Moreover, the TCI's impact on LST shifts from negative to positive as its value increases. The SOI and SWI positively affect LST in all categories. The SEI's effect on LST changes from negative to positive in the total and high-population (HP) categories, and it remains negative in the low-population (LP) category. The RWI positively affects LST in the total category, shifts from negative to positive in the LP category, and remains negative in the HP category. (3) The influence ranking is GSI > SEI > SWI > SOI > TCI > RWI, with GSI being the most significant factor. These findings provide key insights for mitigating street LSTs through design interventions, contributing to sustainable urban development. [ABSTRACT FROM AUTHOR]

The study conducted by Cai et al. examines the relationship between metacognitive strategy use and English achievement among university students in China. Four distinct profiles of strategy use were identified, ranging from low to extremely high. The research suggests a nonlinear relationship between metacognitive strategies and English achievement, with a ceiling effect observed in high and extremely high strategy profiles. The findings offer valuable insights for tailored support to enhance metacognitive strategy use among students at different proficiency levels, contributing to pedagogical practices in the context of L2 acquisition. [Extracted from the article]

When using the Transformer model for wind power prediction, the presence of noise in wind power data and the model's final layer relying solely on a simple linear output reduces the model's ability to capture nonlinear relationships, leading to a decrease in prediction accuracy. To address these issues, this paper proposes an ultrashort-term wind power prediction model based on exponential weighted moving average (EWMA) data processing and Kolmogorov–Arnold Network (KAN)-Transformer. First, multiple variable features are smoothed using EWMA, which suppresses noise while preserving the original data trends. Then, the EWMA-processed data is input into the Encoder and Decoder modules of the Transformer model to extract features. The output from the Decoder layer is then passed through the KAN layer, built using a cubic B-spline function, to enhance the model's ability to capture nonlinear relationships, thereby improving the prediction accuracy of the Transformer model for wind power. Finally, experimental analysis is conducted, and it shows that the proposed model achieves the highest prediction accuracy, with a mean absolute error of 4.38 MW, a root mean squared error of 7.37 MW, and a coefficient of determination of 98.73%. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic and similar public health emergencies have significantly impacted global travel patterns. Analyzing the recovery characteristics of subway station-level passenger flow during the pandemic recovery phase can offer unique insights into public transportation operations and guide practical planning efforts. This pioneering study constructs a station-level passenger flow recovery resilience (PFRR) index during the rapid recovery phase using subway AFC system swipe data. Additionally, it develops an analytical framework based on a multiscale geographically weighted regression (MGWR) model, the improved gray wolf optimization with Levy flight (LGWO), and light gradient boosting machine (LightGBM) regression to analyze passenger flow resilience on weekdays and weekends in relation to land use-related built environment types. Finally, SHAP attribution analysis is used to study the nonlinear relationships between built environment variables and PFRR index. The results show significant spatial heterogeneity in the impact of commercial, recreational, and residential land, as well as POI (points of interest) of leisure and shopping on PFRR. On weekdays, the most relevant built environment variables for PFRR are POI of enterprises and shopping numbers. In contrast, the contribution of built environment variables affecting PFRR of weekend is more balanced, reflecting the recovery of non-essential travel on weekends. Most land use-related built environment variables exhibit nonlinear associations with PFRR values. The proposed analytical framework shows significant performance advantages over other baseline models. This study provides unique insights into subway passenger flow characteristics and surrounding land use-related development layouts under the impact of public health emergencies. [ABSTRACT FROM AUTHOR]

Abstract To investigate the non-linear relationship between diabetes mellitus (DM) duration and the development of diabetic retinopathy (DR). By investigating the association between these variables, our goal is to contribute to the existing knowledge regarding the impact of DM duration on the development and severity of DR. A retrospective cross-sectional study was conducted on 420 patients in the Department of Endocrinology at Guangdong Provincial People’s Hospital, who had undergone ophthalmic consultations from December 2017 to November 2018. The analysis of DM duration and DR utilized a generalized additive model to identify both linear and non-linear connections. The threshold effect was determined using a two-piece regression model. The study included a total of 420 patients, with a mean age of 58.7 years. Of these, 56.9% (239/420) were male. The prevalence of DR was 38.33% (161/420). After adjusting for confounding factors, a nonlinear relationship between DM duration and DR was observed, with a turning point at 8 years. On the left side of the turning point, the prevalence increased by 24% per 1-year increase in DM duration (OR: 1.24; 95% CI: 1.11–1.38; P

Abstract The paper analyzes the relationship between urbanization rates, the growing reliance on renewable electricity production, and CO2 emissions per capita. It further examines the economic impact of these urbanization and renewable electricity production variables on GDP per capita using threshold regression and annual data from Jordan covering the period from 1990 to 2022. The objective is to determine whether Jordan can reduce CO2 emissions despite high urbanization rates by increasing the share of renewable energy in electricity production. The fundamental assumption is that the relationship between CO2 emissions and urbanization rates varies according to the share of renewable energy production. Results from the estimated threshold regression model indicate a decline in CO2 emissions per capita during the period from 2004 to 2018, when urbanization rates ranged between 0.78 and 0.91. During this time, the compound growth rate of renewable energy share in electricity production was 24% in regime 2 (2004–2018). In contrast, CO2 emissions per capita increased both before and after this period, suggesting a nonlinear relationship between urbanization rates and CO2 emissions. This nonlinearity implies that Jordan can manage the conflicting goals of the Sustainable Development Goals (SDGs)—sustainable urbanization and low CO2 emissions—by enhancing the share of renewables in electricity production. Additionally, the results demonstrate a positive effect of urbanization rates and renewable energy shares on economic growth.

In this study, numerical simulations of centrifugal compressors are carried out using ANSYS-CFX software. The focus lies in investigating the impact of the inlet tip-clearance (ITC) on the characteristics of the internal complex flow and the aerodynamic performance of centrifugal compressors. Specifically, the paper mainly emphasizes the influence of ITC on the polytropic efficiency and total pressure ratio of a centrifugal compressor, as well as the variations in velocity and pressure at the blade tip, the spatiotemporal evolution of the tip-leakage vortex (TLV), and fluctuations in pressure and velocity downstream of the passage near the blade surface. Analysis of tip-leakage flow (TLF) and TLV motion patterns at rated operating conditions reveals the spatiotemporal evolution within one revolution. Results from Fast Fourier Transform (FFT) spectrum analysis indicate that the TLV motion pattern may be affected by the ITC size. The fluid flow resistance and backflow in the blade tip region are gradually reduced, the flow field stability is effectively enhanced, and the reflux vortex at the volute outlet is eliminated, thereby the working range of the centrifugal compressor is effectively extended by decreasing the ITC. The aerodynamic performance of the centrifugal compressor is effectively increased in the range of the medium and high flow rates by decreasing ITC. Additionally, it is observed that pressure, velocity, and load in the blade tip region do not exhibit a linear relationship with ITC, resulting in a nonlinear change in aerodynamic performance concerning ITC. Pressure and velocity spectrum analysis suggests that the effect of TLF is stronger at the top of the flow passage compared to the middle. Moreover, with the increase of ITC, the effect of TLF decreases at the middle and top of the pressure side (PS) while increasing at the bottom of PS and the suction side (SS).

Yifei Lu,1,&ast; Minhua Ye,2,&ast; Dehua Ma,2 Yu Chen2 1Department of Cardiology, Taizhou Hospital of Zhejiang Province Affiliated to Wenzhou Medical University, Linhai, People’s Republic of China; 2Department of Thoracic Surgery, Taizhou Hospital of Zhejiang Province affiliated to Wenzhou Medical University, Linhai, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Yu Chen; Dehua Ma, Email chenyu5835@126.com; madh@enzemed.comObjective: To explore the association between survival status and the number of resected lymph nodes in node-negative esophageal squamous cell carcinoma(ESCC) after surgical treatment.Methods: This was a retrospective observational cohort study and data were obtained from the Surveillance, Epidemiology, and End Results program (SEER) and TaiZhou hospital in China. The data for subjects with negative lymph nodes and no distant metastasis (pN0M0) after post-operative pathology were screened. The nonlinear relationship between resected lymph node number and survival status in node-negative ESCC was conducted using restricted cubic spline regression analysis. The association between the number of resected lymph nodes and survival status in node-negative ESCC was evaluated by Cox proportional hazards regression models. Subgroup analysis based on different subgroups was also performed.Results: A total of 999 subjects were included in the study. Restricted cubic spline regression was used to show a U shaped association between the number of resected lymph nodes and survival status in node-negative ESCC, with low count associated with a decreased survival. To elucidate the association, we adjusted for age, sex, race, T stage, TNM (tumor node metastasis classification), location, grade, chemotherapy, and radiotherapy. As the resected lymph node number increased by one node, the survival status was improved by 2% (Hazard ratio(HR) = 0.98, 95% confidence interval (CI) 0.98– 0.99). Sensitivity analysis indicate that the effect size and direction in different subgroups are consistent, the results is stability in SEER.Conclusion: A low count of resected lymph nodes correlated with reduced survival in patients with ESCC, where resecting 25 to 28 or more nodes is considered optimal. Larger prospective studies are warranted to confirm these findings.Keywords: number of lymph node resection, survival status, cohort study, nonlinear relationship, node-negative esophageal squamous cell carcinoma

Abstract Purpose Muscle Quality Index (MQI), defined as the muscle strength per unit of muscle mass, is considered an emerging indicator of health and physical function. This study aims to explore the relationship between MQI and the risk of depression among non-elderly US adults. Methods This cross-sectional study collected data from participants aged between 20 and 59 years old, utilizing the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2014. The MQI was calculated by dividing the handgrip strength (HGS, kg) by the arm and appendicular skeletal muscle mass (ASM, kg). Depression assessments were conducted using the Patient Health Questionnaire (PHQ-9). The relationship between MQI and the risk of depression was explored by weighted logistic regression, smooth curve fitting, and subgroup analyses. Results A total of 4773 participants were included in this study. After adjusting for confounding factors, low MQI levels were identified as an independent risk factor for depression (OR = 0.800, 95%CI:0.668–0.957, P = 0.015). Smooth curve fitting analysis indicated a nonlinear relationship. Subgroup analysis did not identify any specific populations. Conclusions Higher MQI levels were closely associated with a lower risk of depression among non-elderly US adults. MQI could enhance our understanding of the link between muscle and depression and might serve as a simple functional measure for evaluating and predicting depression.

Abstract Contradictory to conventional economic theory, which foresees any increase in the size of government as inflationary, this article provides evidence that the reaction of price levels to changes in the size of government is nonlinear. The price levels do not necessarily increase in response to a rise in the size of the government but only up to a certain threshold or optimal level. Accordingly, this paper utilizes the dynamic panel threshold model to examine the threshold effects of government size (measured as government final consumption expenditure as a proportion of GDP) on inflation using a sample of 10 selected MENA countries from 1980 to 2019. The findings of this study stand out in several ways. First, the results support the nonlinear relationship between government size and inflation in the study area. Second, the government size’s estimated threshold level is equivalent to 12.46%. Third, government size negatively impacts inflation in the regime of small governments up to the threshold level. The impact turns positive once the government size goes beyond the threshold level in a regime of large size of government. These findings have ramifications for the conduct of fiscal policy. Policymakers in the MENA region can increase the size of government till it reaches the threshold level without exerting any upward pressure on price levels.

Background While the connection between monounsaturated fatty acid (MUFA) intake and non-alcoholic fatty liver disease (NAFLD) has received attention, research in Chinese populations remains scarce. Objective This study aims to evaluate the association between daily MUFA intake and the prevalence of NAFLD in a Chinese population and to estimate the probable threshold of MUFA intake for NAFLD risk. Methods This case-control study employed data from the Dryad database (https://doi.org/10.5061/dryad.8nn2j46), complying with Dryad's terms of service. We collected data from 534 NAFLD patients and 534 healthy controls who underwent medical tests at the First Hospital of Nanping Affiliated to Fujian Medical University between April 2015 and August 2017. A semi-quantitative food frequency questionnaire (SQFFQ) was used to collect individuals' typical food consumption information, and daily MUFA intake was computed. A thorough analytical technique, including baseline characteristics, multivariate statistics, non-linear relationship analysis, and subgroup research, was applied to study the correlation between daily MUFA intake and NAFLD prevalence. Multiple confounding factors, such as age, sex, lifestyle, and other dietary components, were evaluated to estimate the theoretical threshold of MUFA intake for NAFLD risk. Results In the adjusted model, daily MUFA intake was a significant risk factor for NAFLD (OR=1.04, 95%CI=1.02-1.07, P

Abstract Implementing the strongly coupled data assimilation (SCDA) in coupled earth system models remains big challenging, primarily due to accurately estimating the coupled cross background-error covariance. In this work, through simplified two-variable one-dimensional assimilation experiments focusing on the air–sea interactions over the tropical pacific, we aim to clarify that SCDA based on the variance–covariance correlation, such as the ensemble-based SCDA, is limited in handling the inherent nonlinear relations between cross-sphere variables and provides a background matrix containing linear information only. These limitations also lead to the analysis distributions deviating from the truth and miscalculating the strength of rare extreme events. However, free from linear or Gaussian assumptions, the application of the data-driven machine learning (ML) method, such as multilayer perceptron, on SCDA circumvents the expensive matrix operations by avoiding the explicit calculation of background matrix. This strategy presents comprehensively superior performance than the conventional ensemble-based assimilation strategy, particularly in representing the strongly nonlinear relationships between cross-sphere variables and reproducing long-tailed distributions, which help capture the occurrence of small probability events. It is also demonstrated to be cost-effective and has great potential to generate a more accurate initial condition for coupled models, especially in facilitating prediction tasks of the extreme events.

Abstract This study addresses the relationship between platelet count and 30-day in-hospital mortality in End-Stage Kidney Disease (ESRD) patients in the intensive care unit (ICU), a topic with limited existing evidence. Utilizing data from the US eICU-CRD v2.0 database (2014–2015), a retrospective cohort study was conducted involving 3700 ICU ESRD patients. We employed binary logistic regression, smooth curve fitting, and subgroup analyses to explore the association between platelet count and 30-day in-hospital mortality. The 30-day in-hospital mortality rate was 13.27% (491/3700), with a median platelet count of 188 × 109/L. After adjusting for covariates, we observed a relationship between platelet count and 30-day in-hospital mortality (OR = 0.98, 95% CI 0.97, 0.99). Subgroup analyses supported these findings. More importantly, a nonlinear association was detected, with an inflection point at 222 × 109/L. The effect sizes (OR) on the left and right sides of the inflection point were 0.94 (0.92, 0.96) and 1.03 (1.00, 1.05), respectively. The most significant finding of this study is the revelation of a nonlinear relationship between baseline platelet count and 30-day in-hospital mortality in ICU patients with ESRD. This discovery explicitly suggests that when ESRD patients are admitted to the ICU, a platelet level closer to 222 × 10⁹/L may predict a lower 30-day in-hospital mortality risk.

The calculation method for negative skin friction of a single pile has not been unified yet. To improve the design and calculation level of the single pile under vertical load considering negative skin friction, the threshold limit value of pile skin friction was determined based on the effective stress method. The effects of relative displacement of pile-soil and pile depth on pile skin friction were analyzed, and a nonlinear calculation model for pile skin friction was established. The pile skin friction was divided into elastic and plastic states. In the elastic range, the friction is a quadratic function with the depth of the pile body; while in the plastic range, the friction is distributed linearly along the pile body, and the slope is the product of the effective weight of the soil around the pile and the negative friction coefficient. Consequently, the analytical solution of the pile skin friction for the corresponding pile section was acquired. Based on the theory of pile axial force calculation, a formula for calculating the axial force of a single pile under different distribution forms of pile lateral friction was obtained. The reliability, applicability, and practicality of this model were verified by measured data. Based on the calculated pile shaft axial force, the axial force of single pile with different distributions of skin friction was analyzed. This study has practical significance for fully utilizing the performance of pile foundations and improving the level of pile foundation design.

Abstract Metabolic dysfunction associated fatty liver disease (MAFLD) is a common cause of liver disease in children and adolescents. The relationship between insulin resistance (IR) and MAFLD in children with short stature remains largely unknown. The present study was to investigate the relationship between the triglyceride–glucose (TyG) index and alanine aminotransferase (ALT) levels in children with short stature. A total of 1754 children with short stature were enrolled. Anthropometric, biochemical and hormonal indexes were collected through physical measurement examinations and laboratory tests. A nonlinear association was found between the TyG index and ALT. The inflection point of the curve was at a TyG index of 8.24. In multivariate piecewise linear regression, only when the TyG index was greater than 8.24 was there a significant positive association between the TyG index and ALT (β 5.75, 95% CI 3.30, 8.19; P < 0.001). However, when the TyG index was less than 8.24, there was no significant association between the TyG index and ALT (β −0.57, 95% CI −1.84, 0.71; P = 0.382). This study demonstrated a nonlinear relationship between TyG index and ALT in children with short stature. This finding suggests that a high TyG index is associated with elevated ALT in children with short stature.

Abstract In the process of penicillin fermentation, there is a strong nonlinear relationship between the input eigenvector and multiple output vectors, which makes the prediction accuracy of the existing model difficult to meet the requirements of chemical production. Therefore, a local selective ensemble learning multi-objective soft sensing modeling strategy is proposed in this study. Firstly, a localization method based on transfer entropy and k-means is proposed to reconstruct the sample set. Then, based on the reconstructed local samples, the local soft sensing model is established by the multi-objective support vector regression method, and the selective ensemble of sub-models and the adaptive calculation of prediction weights are realized. At the same time, to reduce the adverse effects caused by improper selection of model parameters, the sparrow search algorithm is used to realize the tuning of the mentioned model parameters. Finally, the proposed modeling strategy is simulated. The results show that, compared with other methods, the proposed local selective ensemble learning multi-objective soft sensing modeling strategy has better prediction performance.

Abstract Background and aims Numerous research have focused on the relationship of metabolic markers and stroke risk, yet limited research has focused on the triglyceride glucose-waist circumference (TyG-WC) index. This study explored the possible association of TyG-WC and stroke among moderately aged and old Chinese adults over 45 years of age. Methods This observational cohort analysis involved 9054 participants from the Chinese Longitudinal Study of Health and Retirement and employed a standardized questionnaire administered via in-person interviews. Cox proportional hazard model, smoothed curve fitting, and threshold effect analysis were conducted for examining the potential nonlinear relationships among TyG-WC and stroke risk. Results Within an average follow-up period of six years, 463 new strokes occurred, representing 5.11% of the total number of patients. After adjusting for possible confounding factors, a nonlinear association between TyG-WC and stroke risk was identified, with a significant dose–response relationship (P = 0.023 for the log-likelihood ratio test). A turning point was identified at the TyG-WC level of 554.48, beyond that the likelihood of stroke increased markedly (HR = 1.323, 95% CI = 1.098–1.594, P = 0.003). Conclusion This study revealed a specific curvilinear association with the TyG-WC score and stroke risk, identifying a key threshold value. This study focused on Chinese middle-aged and senior adults over the age of 45, emphasizing that increased stroke risk is linked to higher TyG-WC levels.

Purpose: Muscle Quality Index (MQI), defined as the muscle strength per unit of muscle mass, is considered an emerging indicator of health and physical function. This study aims to explore the relationship between MQI and the risk of depression among non-elderly US adults. Methods: This cross-sectional study collected data from participants aged between 20 and 59 years old, utilizing the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2014. The MQI was calculated by dividing the handgrip strength (HGS, kg) by the arm and appendicular skeletal muscle mass (ASM, kg). Depression assessments were conducted using the Patient Health Questionnaire (PHQ-9). The relationship between MQI and the risk of depression was explored by weighted logistic regression, smooth curve fitting, and subgroup analyses. Results: A total of 4773 participants were included in this study. After adjusting for confounding factors, low MQI levels were identified as an independent risk factor for depression (OR = 0.800, 95%CI:0.668–0.957, P = 0.015). Smooth curve fitting analysis indicated a nonlinear relationship. Subgroup analysis did not identify any specific populations. Conclusions: Higher MQI levels were closely associated with a lower risk of depression among non-elderly US adults. MQI could enhance our understanding of the link between muscle and depression and might serve as a simple functional measure for evaluating and predicting depression. [ABSTRACT FROM AUTHOR]

Contradictory to conventional economic theory, which foresees any increase in the size of government as inflationary, this article provides evidence that the reaction of price levels to changes in the size of government is nonlinear. The price levels do not necessarily increase in response to a rise in the size of the government but only up to a certain threshold or optimal level. Accordingly, this paper utilizes the dynamic panel threshold model to examine the threshold effects of government size (measured as government final consumption expenditure as a proportion of GDP) on inflation using a sample of 10 selected MENA countries from 1980 to 2019. The findings of this study stand out in several ways. First, the results support the nonlinear relationship between government size and inflation in the study area. Second, the government size's estimated threshold level is equivalent to 12.46%. Third, government size negatively impacts inflation in the regime of small governments up to the threshold level. The impact turns positive once the government size goes beyond the threshold level in a regime of large size of government. These findings have ramifications for the conduct of fiscal policy. Policymakers in the MENA region can increase the size of government till it reaches the threshold level without exerting any upward pressure on price levels. [ABSTRACT FROM AUTHOR]

A debate has taken place on the relationship between challenge and skills as the universal precondition of flow. Flow's precursor, Csikszentmihalyi, states that these two constructs are independent, while other scholars state the opposite. This research aims to better understand this relationship and explore its effect on the flow experience. As flow is considered a nonergodic and nonlinear process, we will base our analysis on an intra-individual level and then shift to an inter-individual level. The database consisted of 3,630 registers collected from a sample of 60 employees. At an intra-individual level, we observed the nature of the challenge-skills relationship classifying the participants according to the direction of these relationships (positive, negative, or nonsignificant correlation). At the inter-individual level, we explored the effect that the three groups had on the flow experience. We also examined nonlinear relationships (cusp modeling) among challenge, skills, and flow. The results showed that the challenge-skills relationship is not homogeneous between individuals. Flow theory is represented by the positive correlation group, but this pattern is the least frequent (21.6% of the cases) in our sample. Finally, the results showed that the nonlinear models fit the data better (R²nonlinear = .48, R²linear = .35, p < .01). [ABSTRACT FROM AUTHOR]

This study addresses the relationship between platelet count and 30-day in-hospital mortality in End-Stage Kidney Disease (ESRD) patients in the intensive care unit (ICU), a topic with limited existing evidence. Utilizing data from the US eICU-CRD v2.0 database (2014–2015), a retrospective cohort study was conducted involving 3700 ICU ESRD patients. We employed binary logistic regression, smooth curve fitting, and subgroup analyses to explore the association between platelet count and 30-day in-hospital mortality. The 30-day in-hospital mortality rate was 13.27% (491/3700), with a median platelet count of 188 × 109/L. After adjusting for covariates, we observed a relationship between platelet count and 30-day in-hospital mortality (OR = 0.98, 95% CI 0.97, 0.99). Subgroup analyses supported these findings. More importantly, a nonlinear association was detected, with an inflection point at 222 × 109/L. The effect sizes (OR) on the left and right sides of the inflection point were 0.94 (0.92, 0.96) and 1.03 (1.00, 1.05), respectively. The most significant finding of this study is the revelation of a nonlinear relationship between baseline platelet count and 30-day in-hospital mortality in ICU patients with ESRD. This discovery explicitly suggests that when ESRD patients are admitted to the ICU, a platelet level closer to 222 × 10⁹/L may predict a lower 30-day in-hospital mortality risk. [ABSTRACT FROM AUTHOR]

Implementing the strongly coupled data assimilation (SCDA) in coupled earth system models remains big challenging, primarily due to accurately estimating the coupled cross background-error covariance. In this work, through simplified two-variable one-dimensional assimilation experiments focusing on the air–sea interactions over the tropical pacific, we aim to clarify that SCDA based on the variance–covariance correlation, such as the ensemble-based SCDA, is limited in handling the inherent nonlinear relations between cross-sphere variables and provides a background matrix containing linear information only. These limitations also lead to the analysis distributions deviating from the truth and miscalculating the strength of rare extreme events. However, free from linear or Gaussian assumptions, the application of the data-driven machine learning (ML) method, such as multilayer perceptron, on SCDA circumvents the expensive matrix operations by avoiding the explicit calculation of background matrix. This strategy presents comprehensively superior performance than the conventional ensemble-based assimilation strategy, particularly in representing the strongly nonlinear relationships between cross-sphere variables and reproducing long-tailed distributions, which help capture the occurrence of small probability events. It is also demonstrated to be cost-effective and has great potential to generate a more accurate initial condition for coupled models, especially in facilitating prediction tasks of the extreme events. [ABSTRACT FROM AUTHOR]

Metabolic dysfunction associated fatty liver disease (MAFLD) is a common cause of liver disease in children and adolescents. The relationship between insulin resistance (IR) and MAFLD in children with short stature remains largely unknown. The present study was to investigate the relationship between the triglyceride–glucose (TyG) index and alanine aminotransferase (ALT) levels in children with short stature. A total of 1754 children with short stature were enrolled. Anthropometric, biochemical and hormonal indexes were collected through physical measurement examinations and laboratory tests. A nonlinear association was found between the TyG index and ALT. The inflection point of the curve was at a TyG index of 8.24. In multivariate piecewise linear regression, only when the TyG index was greater than 8.24 was there a significant positive association between the TyG index and ALT (β 5.75, 95% CI 3.30, 8.19; P < 0.001). However, when the TyG index was less than 8.24, there was no significant association between the TyG index and ALT (β −0.57, 95% CI −1.84, 0.71; P = 0.382). This study demonstrated a nonlinear relationship between TyG index and ALT in children with short stature. This finding suggests that a high TyG index is associated with elevated ALT in children with short stature. [ABSTRACT FROM AUTHOR]

Gaining an understanding of the intricate mechanisms between human activity and the built environment can help in promoting sustainable urban development. However, most scholars have focused on residents' life and work behavior and have ignored the third activity (e.g., shopping, eating, and entertainment). In this study, a random forest algorithm and SHapley Additive exPlanation model were utilized to explore the nonlinear influence of the built environment on the attraction of the third activity (other than home and work). A comparative analysis of the inflow of the third activity from home and work was also carried out. The results show that the contributions of all built environment variables to the attraction of the third activity differ between home–other flow (HO) and work–other flow (WO) at the global scale, but their local effects are significantly similar. Furthermore, the nonlinear influence of the built environment on the attractions of the third activity can vary from one factor to another. A significant spatial heterogeneity can be observed on the built environment variables' local effects on the attractions of the third activity. These findings can provide urban planners with insights that will help in the planning and optimization of communities for pursuing the third activity. [ABSTRACT FROM AUTHOR]

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Background and aims: Numerous research have focused on the relationship of metabolic markers and stroke risk, yet limited research has focused on the triglyceride glucose-waist circumference (TyG-WC) index. This study explored the possible association of TyG-WC and stroke among moderately aged and old Chinese adults over 45 years of age. Methods: This observational cohort analysis involved 9054 participants from the Chinese Longitudinal Study of Health and Retirement and employed a standardized questionnaire administered via in-person interviews. Cox proportional hazard model, smoothed curve fitting, and threshold effect analysis were conducted for examining the potential nonlinear relationships among TyG-WC and stroke risk. Results: Within an average follow-up period of six years, 463 new strokes occurred, representing 5.11% of the total number of patients. After adjusting for possible confounding factors, a nonlinear association between TyG-WC and stroke risk was identified, with a significant dose–response relationship (P = 0.023 for the log-likelihood ratio test). A turning point was identified at the TyG-WC level of 554.48, beyond that the likelihood of stroke increased markedly (HR = 1.323, 95% CI = 1.098–1.594, P = 0.003). Conclusion: This study revealed a specific curvilinear association with the TyG-WC score and stroke risk, identifying a key threshold value. This study focused on Chinese middle-aged and senior adults over the age of 45, emphasizing that increased stroke risk is linked to higher TyG-WC levels. [ABSTRACT FROM AUTHOR]

This paper examines the impact mechanism of the proportion of female executives on ESG investment. The results show that when female executives play a greater role in management, ESG performance improves. This effect is an inverted U-shape, and the critical point is approximately 33%. Female executives have significantly promoted the digitization of enterprises, which is an important mechanism for explaining the improvement of ESG performance. [ABSTRACT FROM AUTHOR]

This paper investigates the underlying causes of the nonlinear link between financial asset holdings and innovative efficiency. It identifies an inverted U‐shaped pattern linking corporate financialization to innovation, with financing restrictions, agency costs, and business risk serving as some of the relationship's partial mediating factors. By categorizing financial assets into short‐term monetary and long‐term nonmonetary types, it reveals heterogeneous effects on innovative efficiency, suggesting that the impact is not solely crowding out or a pulling effect but varies based on asset type and proportion. Additionally, it argues for continual adjustment of proper corporate financialization levels based on firm‐specific factors and changing external conditions. Notably, excessive financialization appears less prevalent among Chinese firms, with internal governance and external environmental enhancements recommended to optimize financialization for innovation. [ABSTRACT FROM AUTHOR]

In the context of global climate change, improving agricultural carbon productivity is an important channel to cope with climate change, reduce agricultural carbon emissions and maintain agricultural growth. For a long time, agricultural development in China mainly depends on the government's fiscal expenditure. However, does fiscal support helps to promote carbon productivity of agriculture? This question remains to be answered. Using a set of panel data covering 31 provinces and cities from 2003 to 2019, this study empirically explores the impact of agricultural fiscal support on agricultural carbon productivity in China. Benchmark regression results indicate that after controlling other influential factors, regional fiscal expenditure on agricultural has a significantly positive impact on agricultural carbon productivity. In addition, the promotion impacts of fiscal support on agricultural technological innovation and scale operation efficiency are two effective channels by which to help promote agricultural carbon productivity. By using a panel threshold regression model, we find that there exists a nonlinear relationship between fiscal support and agricultural carbon productivity. The input of agricultural machinery and chemical fertilizer are two threshold variables. Further, this causal linkage between fiscal support and agricultural carbon productivity exists differences because of the different levels of agricultural carbon productivity and regions. Our research provides Chinese theoretical basis and practical reference for improvement of agricultural carbon productivity from the perspective of fiscal expenditure. [ABSTRACT FROM AUTHOR]

Studies on the relationship between serum sex hormone-binding globulin (SHBG) levels and chronic kidney disease (CKD) remain limited and inconclusive. Therefore, this study aims to evaluate the effects of SHBG on CKD in a nationally representative population. We included a total of 7713 adults from the National Health and Nutrition Examination Survey (NHANES) conducted between 2013 and 2016. Multivariate logistic regression models were utilized to evaluate the association between SHBG levels and CKD, and odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Additionally, we employed a restricted cubic-spline regression model to explore potential dose-response associations. Among the participants, 4030 (52.2%) were women, and CKD was observed in 13.50% (1043/7713). After adjusting for various variables, SHBG levels were found to be associated with the risk of CKD (OR: 1.24; 95% CI: 1.11–1.38), indicating a 24% higher risk of CKD for SHBG levels (log2-transformed). A comparison between the highest quartile (Q4) and the lowest quartile (Q1) of SHBG levels revealed an OR of 1.51 (95% CI: 1.17–1.95) for CKD prevalence. Notably, while the association between SHBG and the risk of CKD disappeared when SHBG levels were

BackgroundThe relationship between platelet count and 28-day mortality in critically ill patients with infective endocarditis (IE) is currently not well established.ObjectiveThis study aims to investigate the impact of platelet count on 28-day mortality in critically ill patients with infective endocarditis.MethodsA retrospective cohort study was conducted involving 450 participants diagnosed with infective endocarditis and admitted to intensive care units (ICU). Vital signs, laboratory parameters and comorbidity were collected for all participants to analyze the association between platelet count and 28-day mortality. In order to assess the independent association between platelet count and 28-day mortality, we employed multivariable cox hazard regression analyses and smooth curve fitting. A further analysis was conducted using a two-piecewise linear regression model to examine the nonlinear association between platelet count and in-hospital mortality.ResultsA total of 450 critically ill patients with infective endocarditis were included in the study. The mean age was 57.4 years, and 64.2% were male. The overall 28-day mortality rate was 20%. A non-linear relationship was observed between platelet count and 28-day mortality. Two different slopes were identified, with correlations between platelet count and 28-day mortality in patients with IE differing significantly below and above the inflection point, which was approximately 141 K/µl. On the left side of the inflection point, the hazard ratio was 0.990 (hazard ratio: 0.990, 95% confidence interval: 0.982–0.997, p = 0.006). However, on the right side of the inflection point, the hazard ratio increased marginally to 1.0004 (HR: 1.0004, 95% CI: 0.997–1.004, p = 0.825). Notably, the association lacked statistical significance on the right side of the inflection point.ConclusionA nonlinear association between platelet count and 28-day mortality was observed in critically ill patients with infective endocarditis. The optimal platelet count associated with the lowest risk of 28-day mortality was above 141 k/µl.

Background and aimEstimated glomerular filtration rate (eGFR) is a key indicator of kidney function and is associated with numerous health conditions. This study examines the association between eGFR and cardiovascular disease (CVD) risk in a representative cohort of the US adult population.MethodsA cross-sectional analysis was conducted using data from the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2018. The study included 31,020 participants aged 20 years and older. The eGFR estimates were calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. CVD was defined as a self-reported physician's diagnosis of congestive heart failure, coronary heart disease, angina pectoris, myocardial infarction, or stroke. To assess the association between eGFR and CVD risk, the study employed weighted linear regression and generalized additive models.ResultsThe study revealed a significant non-linear inverse association between eGFR and CVD risk, with a threshold effect observed at 99.3 ml/min/1.73 m². Below this threshold, each 10-unit increase in eGFR was associated with a 13% decrease in the odds of CVD (OR: 0.87, 95% CI: 0.84–0.90, P

Abstract In the context of contemporary urbanization, the significance of diversifying urban public facilities has attracted significant attention. This study examines the relationship between road network and the diversity of urban public facilities in Changsha City. These factors are measured through the Shannon-Weiner Index and Space Syntax method. To provide greater specificity, the study employs Random Forest and Geographically Weighted Regression models to analyze the relationship between road networks and the diversity of urban public facilities. The results identify a nonlinear relationship between these variables. In addition, high accessibility exhibits a stronger association with diversity than accessibility alone, and this correlation is reflected in varying degrees of inconsistency across different study areas. Finally, the cartographic depiction of diversity clusters is overlaid on the road network, demonstrating a significant relationship between the configuration of the road network and diversity patterns. In conclusion, this research emphasizes the robust correlation between the roadway network and the diversity of urban public facilities. It prompts local governments to focus beyond mere equality, with a greater commitment to enhancing the quality of life for residents through diversity.

Abstract Objective The objective of the present study was to explore the correlation between the advanced lung cancer inflammation index (ALI) and in‐hospital mortality among patients diagnosed with community‐acquired pneumonia (CAP). Methods Data from the Medical Information Mart for Intensive Care‐IV database were adopted to analyze the in‐hospital mortality of ICU patients with CAP. Upon admission to the ICU, fundamental data including vital signs, critical illness scores, comorbidities, and laboratory results, were collected. The in‐hospital mortality of all CAP patients was documented. Multivariate logistic regression (MLR) models and restricted cubic spline (RCS) analysis together with subgroup analyses were conducted. Results This study includes 311 CAP individuals, involving 218 survivors as well as 93 nonsurvivors. The participants had an average age of 63.57 years, and the females accounted for approximately 45.33%. The in‐hospital mortality was documented to be 29.90%. MLR analysis found that ALI was identified as an independent predictor for in‐hospital mortality among patients with CAP solely in the Q1 group with ALI ≤ 39.38 (HR: 2.227, 95% CI: 1.026–4.831, P = 0.043). RCS analysis showed a nonlinear relationship between the ALI and in‐hospital mortality, with a turning point at 81, and on the left side of the inflection point, a negative correlation was observed between ALI and in‐hospital mortality (HR: 0.984, 95% CI: 0.975–0.994, P = 0.002). The subgroup with high blood pressure showed significant interaction with the ALI. Conclusion The present study demonstrated a nonlinear correlation of the ALI with in‐hospital mortality among individuals with CAP. Additional confirmation of these findings requires conducting larger prospective investigations.

Abstract Background The metabolic score for visceral fat (METS-VF) quantifies the cumulative burden of visceral and intra-abdominal adipose tissues. However, the relationship between the METS-VF and carotid atherosclerosis (CAS) has not been extensively explored. Therefore, this study aimed to investigate the association between the METS-VF and CAS. Methods This cross-sectional study enrolled 7089 Chinese adults who underwent physical examinations at the Zhenhai Lianhua Hospital, Zhejiang, China, in 2020. Multivariable logistic regression analysis was used to explore the linear relationship between METS-VF and CAS. Generalised additive models (GAM) were employed to evaluate potential nonlinear associations. The inflection points of METS-VF were determined using segmented logistic regression analysis optimised for maximum likelihood ratios and recursive algorithms. Results Multivariable logistic regression analysis revealed a positive correlation between METS-VF and CAS (odds ratio [OR]: 1.824, 95% confidence interval [CI]: 1.753–1.899; P

Abstract Background Increased intake of specific vitamins has been linked to a decreased prevalence of osteoporosis. However, the association between dietary folate intake and the risk of osteoporosis in the general population remains incompletely understood. Therefore, we aimed to determine the association between dietary folate intake and the risk of osteoporosis in the general population of the USA. Methods In this cross-sectional study, data from the National Health and Nutrition Examination Survey (2017–2020) were collected. Osteoporosis was considered to be indicated by a bone mineral density greater than 2.5 standard deviations below the mean of the young adult reference group. Dietary folate intake was measured by a 24-hour dietary recall. Multivariate logistic regression models and restricted cubic spline models were used. Results The study included 2297 participants (mean age: 63.69 ± 0.35 years), 49.92% of whom were female. In the general population, increased dietary folate intake was directly associated with a decreased risk of osteoporosis (P for trend = 0.005). In the age > 60 years and female subgroups, folate intake was inversely associated with the risk of osteoporosis (P for trend

Abstract Purpose The ratio of non-high-density lipoprotein cholesterol (non-HDL-c) to high-density lipoprotein cholesterol (HDL-c) (NHHR) is a novel comprehensive lipid index. The aim of this study was to investigate the relationship between the NHHR and the prevalence of hyperuricaemia (HUA) in the adult population of the U.S. Methods This cross-sectional study collected data from the National Health and Nutrition Examination Survey (NHANES) (2007–2018). HUA was defined as a serum uric acid (SUA) concentration ≥ 7 mg/dL in men and ≥ 6 mg/dL in women. Multivariate logistic regression models and the restricted cubic spline (RCS) method were applied to examine the relationship between the NHHR and the risk of developing HUA. Subgroup analyses and interaction tests were also performed. Results The prevalence of HUA increased with increasing NHHR values (9.01% vs. 13.38% vs. 17.31% vs. 25.79%, P

Abstract Background Limited evidence exists regarding the link between platelet count and 30-day in-hospital mortality in acute respiratory failure (ARF) patients. Thus, this study aims to investigate this association among ICU patients experiencing acute respiratory failure. Methods We conducted a retrospective cohort study across multiple centers, utilizing data from the US eICU-CRD v2.0 database covering 22,262 patients with ARF in the ICU from 2014 to 2015. Our aim was to investigate the correlation between platelet count and 30-day in-hospital mortality using binary logistic regression, subgroup analyses, and smooth curve fitting. Results The 30-day in-hospital mortality rate was 19.73% (4393 out of 22,262), with a median platelet count of 213 × 109/L. After adjusting for covariates, our analysis revealed an inverse association between platelet count and 30-day in-hospital mortality (OR = 0.99, 95% CI 0.99, 0.99). Subgroup analyses supported the robustness of these findings. Furthermore, a nonlinear relationship was identified between platelet count and 30-day in-hospital mortality, with the inflection point at 120 × 109/L. Below the inflection point, the effect size (OR) was 0.89 (0.87, 0.91), indicating a significant association. However, beyond this point, the relationship was not statistically significant. Conclusion This study establishes a clear negative association between platelet count and 30-day in-hospital mortality among ICU patients with ARF. Furthermore, we have identified a nonlinear relationship with saturation effects, indicating that among ICU patients with acute respiratory failure, the lowest 30-day in-hospital mortality rate occurs when the baseline platelet count is approximately 120 × 109/L.