Investigating the coupling relationships of railway safety risks using the <i>N</i>-<i>K</i> model and complex network theory

by Jiaxu Chen, Lin Zhao, Jinghui Liu, Gaolei Wang, Zhan Guo

To quantitatively analyze the coupling relationships between railway safety risk factors, identify key factors contributing to railway accidents, and develop scientific strategies for accident prevention, this study introduces a complex network-based N-K model to investigate the coupling relationships of railway safety risk factors. First, we identified 18 railway safety risk factors by analyzing case data from railway accidents. The occurrence probabilities and coupling values of these risk factors were then calculated using the N-K model. Subsequently, based on the constructed railway safety risk complex network, reachability and centrality analyses were performed to determine the key factors of railway safety risk. Results indicate that the occurrence of railway accidents is directly proportional to the risk coupling value; the greater the number of coupling factors, the higher the risk value. The coupling of personnel factors and equipment factors is particularly prone to leading to railway accidents. Conversely, effective management of the coupling between personnel and equipment factors can significantly reduce the likelihood of accidents. Inadequate maintenance and unsafe human behavior were identified as critical factors contributing to railway accidents and should be prioritized in prevention efforts.

Burden of chronic obstructive pulmonary disease in adults aged 70 years and older, 1990–2021: Findings from the Global Burden of Disease Study 2021

by Kaifang Meng, Xu Chen, Zhishang Chen, Jing Xu

Background

Life expectancy at age 70 has continued to rise globally over the past 30 years. However, a comprehensive assessment of the burden of COPD in older adults is lacking. We aimed to estimate the burden of COPD and its attributable risk factors among adults aged ≥70 years.

Methods

Data on the prevalence, incidence, deaths, disability-adjusted life years (DALYs), and risk factors of COPD among adults aged ≥70 years from 1990 to 2021 across 204 countries and territories, were sourced from the Global Burden of Disease Study 2021. Estimated annual percentage change (EAPC) was used to illustrate temporal trends at global and regional levels from 1990 to 2021.

Results

In 2021, the global numbers of prevalent and incident COPD cases among older adults were 99.7 and 7.4 million, increasing by 162.2% and 157.4% from 1990. The prevalence and incidence rates increased from 18823.5 (95% uncertainty interval (UI) 16324.4–21208.4) to 20165.6 (17703.8–22549.4) and 1429.0 (1224.2–1613.0) to 1502.7 (1309.0–1677.9) per 100,000 population (EAPC 0.31, 95% CI 0.28–0.33; 0.17, 95% CI 0.16–0.19). The global numbers of COPD-associated deaths and DALYs in 2021 reached 2.9 and 45.4 million, increasing by 70.7% and 70.0% from 2019, while the corresponding rates declined (both EAPC Conclusion

COPD in older adults has progressively become a global health challenge with rising prevalence and incidence rates. Although the death and DALY rates attributed to COPD have globally decreased in older adults, the absolute counts are rapidly increasing. The inequalities across different regions and countries underscore a multi-faceted approach to COPD management in older adults.

A comprehensive study on the risk factors and pathogen analysis of postoperative wound infections following caesarean section procedures

Abstract

Postoperative wound infections (PWIs), a subtype of surgical site infections, are a significant concern for patients undergoing caesarean sections (C-sections). Understanding risk factors and pathogen profiles can greatly assist in early diagnosis and effective treatment. This study aimed to identify risk factors and analyse the pathogenic landscape contributing to PWIs in C-sections. A nested case-control study was carried out, utilising stringent criteria for case selection and control matching. Diagnostic criteria for surgical site infections included both clinical and microbiological parameters. Risk variables examined included patient age, Body Mass Index, duration of surgery and several other clinical indicators. Microbiological analysis was performed using the BD Phoenix-100 Automated Bacterial Identification System. Statistical analyses were conducted using SPSS version 26.0, and risk factors were evaluated through both univariate and multivariate analyses. A total of 50 patients, aged between 20 and 45 years (mean age 26.3 ± 5.6), developed PWIs following C-sections. The study revealed a temporal distribution and various clinical indicators of PWIs, including elevated white blood cell count and C-reactive protein levels. Gram-negative bacteria were found to be more prevalent at 57.4%. Notable pathogens included Pseudomonas aeruginosa and Acinetobacter baumannii. Antimicrobial resistance patterns were also identified, highlighting the need for a targeted antibiotic approach. Increased infection risks were linked to lack of prophylactic antibiotics, absence of preoperative povidone-iodine antisepsis, operations over an hour, anaemia, amniotic fluid contamination, diabetes, GTI, premature rupture of membranes and white blood cells counts above 10 × 10⁹/L. The study provides critical insights into the risk factors and microbial agents contributing to PWIs following C-sections. Our findings emphasise the importance of early diagnosis through clinical and laboratory parameters, as well as the need for constant surveillance and reassessment of antibiotic stewardship programs.