Application of an interpretable machine learning model based on optimal feature selection for predicting triple-vessel coronary disease: a multicenter retrospective study
Objective This study aimed to evaluate the predictive value of the remnant cholesterol-inflammatory index (RCII) in assessing the risk of triple-vessel disease (TVD), and to construct a comparative framework of predictive models using six machine learning algorithms based on RCII and other clinical features for identifying high-risk individuals. Methods In this retrospective multicenter study, we enrolled 2,911 patients who underwent coronary angiography between January 1, 2024, and December 31, 2024, at two tertiary hospitals. Clinical and laboratory data were collected. Feature selection was performed using both Least Absolute Shrinkage and Selection Operator (LASSO) regression and multivariate logistic regression. Six machine learning (ML) algorithms were trained for risk prediction, with multilayer perceptron (MLP) selected as the optimal model for the final feature set. Model performance was assessed using the area under the receiver operating characteristic curve (AUC), positive predictive value (PPV), and F1 score. SHapley Additive exPlanations (SHAP) analysis was applied to interpret feature contributions and interactions. Results A total of 16 features were selected by LASSO regression, while multivariate logistic regression identified six independent predictors. Four overlapping features—gender, age, aspartate aminotransferase (AST), and RCII—were used for ML model development. Among the six models, the MLP demonstrated the best overall performance on the test set. SHAP analysis revealed that RCII, age, AST, and gender were the top contributors to model prediction, with RCII showing notable interaction effects with other variables, highlighting its both independent and synergistic role in TVD risk stratification. Conclusion RCII, as a composite biomarker integrating lipid metabolism and chronic inflammation, demonstrates strong predictive utility in identifying individuals at high risk for triple-vessel coronary disease.
Hou et al. (2025) Application of an interpretable machine learning model based on optimal feature selection for predicting triple-vessel coronary disease: a multicenter retrospective study. PeerJ 13:e20423 https://doi.org/10.7717/peerj.20423
Sex ratios in flux: seasonal dynamics and methodological insights in Rumex species
Dioecy–separate male and female individuals–occurs in less than 10% of angiosperms. Studying dioecy and plant sex chromosomes is key to understanding sex determination, genetic diversity, and ecological interactions, with implications for crop breeding, conservation, and pollination management. Many dioecious plant species deviate from the 1:1 sex ratio expected under Fisher’s principle, displaying male- or female-biased populations. The genus Rumex (Polygonaceae) is a valuable model for investigating sex-ratio variation and sex chromosome evolution. The dioecious species Rumex acetosa and R. thyrsiflorus possess heteromorphic sex chromosomes and typically exhibit female-biased sex ratios in natural populations. However, the environmental and developmental drivers of these biases remain largely unresolved. Previous studies on Rumex have often relied on single or infrequent population surveys, potentially overlooking the seasonal dynamics of sex ratios, especially given phenological differences between sexes. Female plants remain morphologically recognizable for longer periods due to seed set, which can bias sex-ratio estimates when sampling is limited to specific reproductive stages or time points. To address these limitations, we systematically investigated the temporal dynamics of observable sex ratios in R. acetosa and R. thyrsiflorus throughout an entire growing season using regular monitoring. Our results demonstrate that observable sex ratios in these populations are dynamic, with significant seasonal fluctuations driven by differences in developmental timing and the duration of morphological recognizability between sexes. As a result, the period during which field-observed sex ratios accurately reflect the true population structure is both limited and highly dependent on the timing of observations. Notably, the earlier flowering of male plants in R. acetosa can lead to male-biased sex ratios in early-season surveys, while the prolonged recognizability of fruiting females may bias estimates toward females later in the season.
Pawełek et al. (2025) Sex ratios in flux: seasonal dynamics and methodological insights in Rumex species. PeerJ 13:e20391 https://doi.org/10.7717/peerj.20391
Development and content validity of the evaluation of multidimensional functioning and risks in aging scale
Introduction Rising life expectancy has led to an increased prevalence of age-related conditions such as pain, dementia, and falls. To address these challenges, healthcare systems require efficient tools to identify which health domains are preserved or impaired in older adults. Existing frailty instruments present both conceptual and operational limitations. Therefore, there is a need to shift toward domain-specific evaluations of functioning and potential risks, aligned with established protocols such as the Comprehensive Geriatric Assessment and framed within the International Classification of Functioning, Disability and Health (ICF). This study aimed to develop the Evaluation of Multidimensional Functioning and Risks in Aging (EMFRA) scale, encompassing four assessment domains: physical function, cognitive function, emotional status, and social situation. Methods The EMFRA scale was developed by identifying potential items through a comprehensive literature review and expert input. The first preliminary version was validated by a panel of 15 experts, who assessed the scale’s clarity, coherence, and relevance using a 5-point Likert scale. Cognitive interviews were then conducted with 10 clinicians and 10 older adults to evaluate the comprehensibility and practical applicability of the second preliminary version. Results Following the literature review, 24 items were grouped into four domains (six items per domain), each supported by evidence linking them to health-related adverse outcomes. Expert evaluation showed substantial agreement on comprehension, coherence, and relevance (Aiken’s V >0.7) for all but two items—language and fear—which were excluded. Cognitive interviews led to the exclusion of one additional item (sedentarism) and further refinement of the remaining items. These changes were incorporated into the final version of EMFRA, enhancing its usability and comprehensiveness. Conclusion EMFRA provides a multidimensional framework for assessing functioning and risks in older adults, capturing physical, cognitive, emotional, and social factors. The inclusion of end-user feedback ensured the scale’s practical relevance. However, the current version of EMFRA should not yet be used in clinical practice, as further psychometric validation is required to confirm its utility.
Fierro-Marrero et al. (2025) Development and content validity of the evaluation of multidimensional functioning and risks in aging scale. PeerJ 13:e20108 https://doi.org/10.7717/peerj.20108
Chronic cervical instability in mice and rats: a reproducible model to simulate human intervertebral disc degeneration
Background Chronic low-back pain, a leading cause of global disability, is closely linked to intervertebral disc degeneration (IVDD). Traditional animal models have faced challenges in replicating the gradual, chronic nature of human IVDD. Objective To address these limitations, we aimed to develop a novel mouse model of cervical spine instability that more accurately mimics the progressive degeneration observed in humans. Animals This study used 48 male Sprague–Dawley rats (3 months old, weighing 230 ± 20 g) and 48 male C57BL/6 mice (12 weeks old, weighing 20 ± 2 g). Methods A bilateral cervical laminectomy combined with spinous process resection was performed while preserving the facet joints and posterior cervical muscles to induce chronic intervertebral instability. Longitudinal assessments were conducted using in vivo magnetic resonance imaging (MRI), histological staining (H&E and Safranin O-fast green), immunofluorescence and western blot analyses at 4, 8, and 12 weeks post-operation. Results MRI findings demonstrated progressive degeneration at the C4/5, C5/6, and C6/7 levels, with the most pronounced changes observed at 4 and 8 weeks post-surgery and partial recovery at 12 weeks. H&E and Safranin O staining confirmed significant cellular loss, structural disorganization, and proteoglycan depletion in the affected discs. Immunofluorescence staining revealed a progressive decrease in collagen type II and aggrecan expression over time. Conversely, collagen type I expression increased, indicating a shift toward fibrosis. Western blot analysis confirmed elevated levels of oxidative stress markers (albumin and AOPPs), matrix metalloproteinases (MMP3 and MMP13), senescence markers (p53, p21, p16), and inflammatory cytokines (IL-1β, TNF-α) at 4 and 8 weeks, with a partial decline by 12 weeks. Conclusions This innovative cervical instability model not only minimizes the risk of nerve injury and reduces animal stress compared to previous models but also offers a reproducible and ethically sound platform for investigating IVDD pathogenesis and testing potential therapeutic interventions.
Tu et al. (2025) Chronic cervical instability in mice and rats: a reproducible model to simulate human intervertebral disc degeneration. PeerJ 13:e20465 https://doi.org/10.7717/peerj.20465
Neutrophil-to-lymphocyte ratio: a potential supportive marker for elderly community-acquired bloodstream infections—a retrospective study
Background Exploring the value of the neutrophil/lymphocyte ratio (NLR) as a potential supportive marker in community-acquired bloodstream infection in elderly patients. Methods By reviewing the data of inpatients in Xuanwu Hospital of Capital Medical University from January 2012 to December 2021, a total of 58 elderly patients with community-acquired bloodstream infection and 174 inpatients without infection during the same period, matched for age, sex, and concomitant diseases, were included. Clinical data were collected and analyzed statistically. Results There were no significant differences in age, sex, and concomitant diseases between the infected and non-infected groups. Multivariate regression analysis showed that only increased NLR among leukocyte indexes was a risk factor for bloodstream infections. The sensitivity, specificity, and area under the curve (AUC) of increased NLR to support the diagnosis of community-acquired bloodstream infections in the elderly were 0.72, 0.99, and 0.95; the optimal cut-off value is 8.0. Conclusion The increase in NLR was superior to the rise of traditional white blood cell and neutrophil counts. Thus, NLR can be used as an indication for the early diagnosis of community-acquired bloodstream infection in the elderly. The optimal cutoff value of NLR for supporting the diagnosis of community-acquired bloodstream infections in elderly patients was determined to be 8.0. When NLR exceeds this threshold (> 8.0), it serves as a clinical alert for community physicians, indicating a significantly elevated probability of elderly patients developing community-acquired bloodstream infections.
Li et al. (2025) Neutrophil-to-lymphocyte ratio: a potential supportive marker for elderly community-acquired bloodstream infections—a retrospective study. PeerJ 13:e20449 https://doi.org/10.7717/peerj.20449
Validation of an aspiration risk prediction model for Parkinson’s disease based on nomogram: a single-center study
Objective This study aims to develop and validate a predictive model for aspiration risk in patients with Parkinson’s disease (PD). Methods A total of 160 inpatients with PD were enrolled (December 2022 to December 2023) from the Neurology Department of the Affiliated Drum Tower Hospital. Of 33 candidate variables, univariate analysis and Least Absolute Shrinkage and Selection Operator (LASSO) logistic regression were used to identify key predictors and construct a clinical nomogram. Model discrimination and calibration were assessed using receiver operating characteristic (ROC) curves and calibration plots. Results Univariate analysis and LASSO regression reduced the 33 variables to four core predictors: history of choking cough (odds ratio (OR) = 11.427; 95% confidence interval (CI) [2.187–59.709]), abnormal water-swallowing test results (OR = 4.262, 95% CI [1.496–12.140]), reduced facial expression (OR = 2.929, 95% CI [1.055–8.134]), and Barthel Index (OR = 0.972, 95% CI [0.950–0.995]). The area under the curve (AUC) values of the model were 0.882 (optimism-adjusted) and 0.950 for the training and testing sets, respectively. Calibration and decision curve analyses further validated the high performance and clinical utility of this model. Conclusion This nomogram effectively stratified aspiration risk in patients with PD, facilitating earlier detection and intervention. Future studies including more clinical variables and larger multicenter cohorts are required to enhance the predictive accuracy and generalizability of the model.
Xu et al. (2025) Validation of an aspiration risk prediction model for Parkinson’s disease based on nomogram: a single-center study. PeerJ 13:e20443 https://doi.org/10.7717/peerj.20443
Effects and potential mechanisms of iron metabolism on vascular calcification
Vascular calcification (VC) is a prevalent pathological manifestation of cardiovascular and cerebrovascular diseases, and is an active, multifactor-regulated pathological process. Iron is an essential metal that maintains cellular and body functions, and its metabolic homeostasis plays a complex and crucial dual role in the development of VC. This study, based on a comprehensive analysis of numerous studies, revealed that the effect of iron on VC has a significant dose-dependent relationship: physiological concentrations or moderate amounts of iron exert protective effects by enhancing antioxidant defenses, thereby inhibiting the osteogenic phenotype transformation and apoptosis of vascular smooth muscle cells; conversely, iron overload strongly drives VC by inducing oxidative stress, ferroptosis, and pro-inflammatory responses. These findings highlight the importance of maintaining iron homeostasis. Intervention strategies targeting iron metabolism (such as iron-based phosphate binders to correct iron deficiency and iron chelators to alleviate iron overload) have potential clinical value for the prevention and treatment of VC. In summary, this review provides a novel perspective on the diagnosis and treatment of VC, and future studies need to further explore its mechanisms and conduct rigorous clinical validation to manage iron metabolism as a novel approach for personalized prevention and treatment of VC.
Wang et al. (2025) Effects and potential mechanisms of iron metabolism on vascular calcification. PeerJ 13:e20392 https://doi.org/10.7717/peerj.20392
Variations in length of stay among surviving preterm infants admitted to neonatal intensive care units in Shenzhen, China
Background The global preterm birth rate is currently around 10%, making it a major contributor to both neonatal mortality and long-term health complications. Length of stay (LOS) in hospital is a key metric when assessing the quality of medical care for preterm infants. Therefore, a comprehensive analysis of LOS in preterm infants, along with the identification of associated risk factors, is essential in order to improve clinical outcomes and optimize healthcare strategies. Objective This study examined the LOS and total hospitalization costs of preterm infants admitted to neonatal intensive care units (NICUs) in three hospitals in China . The study also investigated the factors affecting the LOS and total hospitalization costs of surviving preterm infants admitted to NICUs. Methods This is a retrospective analysis of preterm infants born between January 2020 and December 2023 who were admitted to one of three participating tertiary care centers within one week after birth. Baseline characteristics, LOS, and hospitalization costs were described and summarized. Generalized linear models were utilized to estimate adjusted associations between LOS and various factors. Results This study included 2,887 preterm infants. The median total LOS was 10 days (interquartile range (IQR): 7–20), and the median total hospitalization cost was RMB ¥16,287.3 (IQR: ¥10,541.9–32,342.3). Both LOS and hospitalization costs decreased significantly with increasing gestational age (GA) and birth weight (BW). Infants at 34 to 36+6weeks’ gestation had a 68% shorter LOS compared to those at <28 weeks (relative risk (RR) 0.32, 95% confidence interval (CI) [0.27–0.38]). Similarly, infants with BW ≥ 2,500 g had a 54% shorter LOS than those <1,000 g (RR 0.46, 95% CI [0.39–0.54]). Conclusion Low GA, low BW, maternal hypertension, low Apgar score , small for GA (SGA), bronchopulmonary dysplasia (BPD), sepsis, and extrauterine growth retardation were associated with prolonged hospitalization.
Rao et al. (2025) Variations in length of stay among surviving preterm infants admitted to neonatal intensive care units in Shenzhen, China. PeerJ 13:e20344 https://doi.org/10.7717/peerj.20344
In situ mechanical behavior of mineralized collagen fibrils in murine cortical bone is altered by aging and disuse
Mineralized collagen fibrils (MCFs) are the fundamental building blocks of bone, determining its mechanical properties. Aging and disuse are known to impair bone mechanics, but their specific effects on the nanoscale, in situ mechanical behavior of MCFs remain poorly understood. The present study utilized a murine model involving adult and aged mice, with a subset from each age group subjected to disuse through hindlimb unloading (n = 6). To investigate the in situ nanomechanical response of bone, murine tibiae were tensile-loaded within a custom-made axial loading device while being simultaneously scanned with atomic force microscopy (AFM). The bone surface was partially demineralized to expose the collagen fibrils. High-resolution AFM imaging in tapping-mode was then employed to quantitatively assess the morphological changes and nanomechanical properties of MCFs throughout the bone’s elastic deformation process. In the adult murine tibia, the initial response to load was characterized by fibril reorientation and an increase in the in situ elastic modulus of MCFs, indicating stretching. It was followed by a sliding phase between adjacent fibrils. In contrast, the aged bone exhibited fibril sliding at the onset of loading, accompanied by a gradual decrease in the elastic modulus of MCFs. The nanomechanical alterations induced by disuse were more pronounced in aged mice compared to adults. The present findings demonstrate that aging and disuse significantly alter the nanoscale deformation mechanisms of bone, shifting the response from fibril stretching to predominant sliding. It provides novel evidence for a unique, age-dependent deformation mechanism at the fibrillar level, enhancing the current understanding of how aging and disuse impair bone quality and mechanics.
Li et al. (2025) In situ mechanical behavior of mineralized collagen fibrils in murine cortical bone is altered by aging and disuse. PeerJ 13:e20313 https://doi.org/10.7717/peerj.20313
Exploring probiotic awareness, perceptions, and practices in the Saudi population: a cross-sectional study
Background Probiotics are composed of trillions of microorganisms, mainly located in the gastrointestinal tract (GIT), which play vital roles in digestion, immunity, and overall well-being. They help maintain gut health and prevent various gastrointestinal disorders. Despite the widespread use of probiotics in developed countries, such as North America and Western Europe, little is known about their use in Saudi Arabia. This study aimed to assess the knowledge, attitudes, and factors influencing probiotic awareness among the Saudi public to support healthier dietary choices. Materials A cross-sectional study using a structured questionnaire titled “Public Knowledge and Perception of Probiotics” was conducted among Saudi residents aged 18 years and older from July to October 2024. With a type I error rate of 5% (α = 0.05) and 80% power, the required sample size was 269; ultimately, 286 individuals participated in the study. Data were analyzed using the Statistical Package for the Social Sciences version 27 (IBM). Results The majority of the 286 participants were female (79%) and over 30 years old (54.9%). Awareness of probiotics was moderate (mean score: 5.2; 65%), with yogurt being the most recognized source (95%). Participants generally had positive perceptions (mean score: 3.74 ± 0.60), although barriers such as limited knowledge (56.2%) and high cost (3.28 ± 1.09) were reported. Probiotic use was noted in 54.5% of the respondents, with 71.2% preferring natural sources. Usage was significantly associated with demographic factors, including age ( $\chi^2$χ2 = 15.251, P < 0.001), education level ( $\chi^2$χ2 = 18.787, P < 0.001), marital status ( $\chi^2$χ2 = 9.825, P = 0.002), and monthly income ( $\chi^2$χ2 = 8.548, P = 0.014). Conclusion While awareness and positive perceptions of probiotics are growing among the Saudi population, challenges such as knowledge gaps, affordability, and limited advertising persist. To promote probiotic use and improve public health outcomes, it is crucial to enhance public health education through schools and community programs, improve affordability via supportive health policies, and encourage greater involvement of healthcare professionals in providing probiotic-related guidance.
Alharbi (2025) Exploring probiotic awareness, perceptions, and practices in the Saudi population: a cross-sectional study. PeerJ 13:e20490 https://doi.org/10.7717/peerj.20490