An improved tortuosity measurement method combining curvature-based, breadth-first search and Euclidean distance for retinal image analysis
Retinal vascular tortuosity is a clinically relevant biomarker linked to systemic and ocular diseases; however, its quantitative assessment particularly the distinction between arteries and veins remains underexplored in both healthy and pathological conditions. This study investigates tortuosity behavior using three publicly available retinal fundus image datasets: Digital Retinal Images for Vessel Extraction (DRIVE), High-Resolution Fundus (HRF), and Labelled Eye fundus Segmentation-Artery Vein (LES-AV). A standardized analytical pipeline combining curvature-based metrics, breadth-first search (BFS) and Euclidean distance was applied following vessel segmentation, artery-vein separation, skeletonization, and optic disc-based tracing. BFS algorithm was utilized for vessel path tracing, chosen for its robustness and suitability in navigating complex vascular structures with high reproducibility. Five comparative analyses were performed: artery vs. vein tortuosity; healthy vs. diseased eyes (glaucoma and diabetic retinopathy); and cross-dataset comparisons under both healthy and pathological conditions. Across all datasets, veins consistently exhibited higher tortuosity than arteries in healthy eyes, confirmed by large effect sizes (Cohen’s d), despite weak correlation between the two vessel types. Diabetic retinopathy cases showed an amplified artery-vein separation, suggesting disease-induced vascular changes. Glaucomatous eyes exhibited mixed patterns, with HRF artery-vein differences maintained and LES-AV showing diminished separation, partly due to non-normal data distribution. A key finding highlights the significant influence of imaging characteristics especially field of view (FOV) on tortuosity measurement. Datasets with a wider field of view, such as DRIVE and HRF (45° FOV, optical disc (OD) positioned nasally), captured more peripheral, tortuous vessels and reported higher tortuosity values. In contrast, the LES-AV dataset with a narrower 30° FOV and centered optic disc, resulted in lower tortuosity measurements and weaker artery-vein differentiation. These anatomical and technical differences emphasize the need to handle FOV and orientation settings when designing or comparing tortuosity-based diagnostic studies. In conclusion, retinal vascular tortuosity appears to be a vessel-specific feature which is robust and capable of capturing both pathological and variations in dataset. The findings support its integration into automated diagnostic frameworks and highlight the importance of standardizing imaging parameters particularly FOV and anatomical orientation in future retinal biomarker research.
Amir Hamzah et al. (2026) An improved tortuosity measurement method combining curvature-based, breadth-first search and Euclidean distance for retinal image analysis. PeerJ 14:e20561 https://doi.org/10.7717/peerj.20561
Comparative anatomy of the thoracic muscles of bees (Hymenoptera: Apoidea)
Bees exhibit a remarkable anatomical diversity, with phenotypic traits that reflect broad evolutionary patterns and specific adaptations. Understanding these patterns requires examining key anatomical features, such as thoracic musculature, which drives morpho-functional variation and underscores their extensive phenotypic diversity. The thorax (or ‘mesosoma,’ as it can be referred to in the context of bees and other apocritan Hymenoptera) serves as a power core, housing muscles responsible for leg, wing, and also head and metasomal articulation movements. Despite the role of the thoracic musculature in the flight mechanics of bees, detailed studies are limited to accounts of individual species or small subsets of muscles, with truly comparative analyses being scarce, leaving gaps in understanding muscular variation and phylogenetic significance. To address this, we conducted detailed dissections of 13 species, representing six bee families (Andrenidae, Apidae, Colletidae, Halictidae, Megachilidae, and Melittidae) and three additional apoid wasp taxa (Bembicidae, Crabronidae, Philanthidae), selected to capture a broad range of morphological and phylogenetic diversity. Our results revealed high conservation in mesosomal musculature, with only 16 of 58 muscle groups showing significant variation, primarily in origin points, suggesting a balance between functional constraints and evolutionary flexibility in muscle attachment. Phylogenetically relevant changes were investigated by coding 17 morphological characters, revealing potential synapomorphies for bees or certain lineages. These include the dorsomedial origin of Idlm1 (M. prophragma-occipitalis) in Meliponini, as evident in species such as Melipona quadrifasciata and Tetragonisca fiebrigi, suggesting a shared derived trait for this tribe. Additionally, the extended origin of IIIscm2 is observed in Andrenidae, Colletidae, and Halictidae, indicating closer evolutionary relationships among these families. Bee-specific modifications, including the non-separation of IItpm7b and IItpm7c by the mesepisternal ridge, distinguished bees from most apoid wasps, interpreted here as a potential synapomorphy for bees. Additional variations, such as the ventral origin of Ivlm3 in select lineages and the branched morphology of IIpcm4, suggest independent evolutionary shifts potentially linked to biomechanical demands. These findings underscore the evolutionary stability and phylogenetic value of bee mesosomal musculature, revealing a conserved framework punctuated by lineage-specific adaptations that may correlate with ecological traits.
Meira et al. (2026) Comparative anatomy of the thoracic muscles of bees (Hymenoptera: Apoidea). PeerJ 14:e20532 https://doi.org/10.7717/peerj.20532
Platelet-lymphocyte ratio and its dynamic changes predict mortality in septic acute kidney injury patients: a retrospective multi-center study using U.S. database and Chinese hospital data
Background The platelet-to-lymphocyte ratio (PLR), a readily available marker that integrates systemic inflammatory burden and immune competence, has emerged as a cost-effective prognostic biomarker in critical care medicine. Elevated PLR has been linked to adverse outcomes across a spectrum of critical illnesses, yet its utility in predicting prognosis among patients with septic acute kidney injury (AKI) remains undefined. Moreover, little is known about how in-hospital trajectories of PLR influence survival outcomes. Method This retrospective study employed data from the Medical Information Mart for Intensive Care IV and West China Hospital of Sichuan University. The primary endpoints were 28-day and 90-day all-cause mortality. The association between baseline PLR/changes in PLR (ΔPLR) and 28-day and 90-day mortality was investigated by survival analysis and Cox proportional hazards models. ΔPLR was calculated as PLR at discharge minus PLR at admission. Patients were stratified based on optimal PLR cut-off values determined from the training cohort, and results were validated internally and externally. Predefined subgroup analyses probed for effect modification across key clinical populations, and mediation analysis was conducted to quantify intermediate variables linking PLR/ΔPLR dynamics to patient outcomes. Result A total of 1,478 patients were included in the baseline-PLR cohort and 982 in the ΔPLR cohort. In the training set, an elevated baseline PLR (≥335.44) was associated with significantly higher 28-day mortality (26.56% vs. 18.66%, P = 0.009) and 90-day mortality (46.48% vs. 35.61%, P = 0.003). These findings were confirmed in both the internal validation cohort and an external cohort, and remained robust after adjustment for demographic, clinical and laboratory confounders. Conversely, lower ΔPLR also predicted the 28-day (14.81% vs. 6.94%, P = 0.007; HR = 2.261, P = 0.005) and 90-day mortality (24.07% vs. 15.41%, P = 0.029; HR = 1.702, P = 0.017), as well as prolonged hospital stay (28.64 vs. 21.64 days, P = 0.004). The associations between PLR or ΔPLR and mortality remained robust after adjusting for confounding factors. Subgroup analyses indicated that the prognostic value of PLR was particularly pronounced in non-urinary tract infection patients, and a low baseline PLR conferred a significant survival benefit in male patients. Mediation analysis revealed that changes in white blood cell count (ΔWBC) mediated 27.99% of the association between ΔPLR and 28-day mortality. Conclusion Both baseline PLR and its dynamic change during hospitalization may serve as significant predictors of mortality in septic AKI. PLR-based indices could aid in risk stratification and early identification of high-risk patients.
Liu et al. (2026) Platelet-lymphocyte ratio and its dynamic changes predict mortality in septic acute kidney injury patients: a retrospective multi-center study using U.S. database and Chinese hospital data. PeerJ 14:e20522 https://doi.org/10.7717/peerj.20522
Extracorporeal shockwave therapy versus sham extracorporeal shockwave therapy for chronic Achilles tendinopathy: a meta-analysis of randomized controlled trials
Background Chronic Achilles tendinopathy is a persistent and debilitating condition. Extracorporeal shockwave therapy (ESWT) is widely used, but its true effectiveness and safety for chronic Achilles tendinopathy remains debated. This study aimed to compare the effectiveness and safety of ESWT and sham ESWT for chronic Achilles tendinopathy. Methods Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, PubMed, EMBASE, Cochrane Library, and Web of Science were systematically searched for randomized controlled trials (RCTs) comparing ESWT with sham ESWT in chronic Achilles tendinopathy. Primary outcomes included pain reduction (change in Visual Analog Scale (ΔVAS), minimal clinically important difference (MCID) 1.1/10) and functional improvement (change in Victorian Institute of Sports Assessment-Achilles (ΔVISA-A), MCID 8/100; change in American Orthopaedic Foot and Ankle Society (ΔAOFAS), MCID 12/100). Secondary outcomes encompassed adverse events. Risk of bias was assessed via Risk of Bias 2 (RoB2). Meta-analysis used RevMan 5.4.1, with weighted mean differences (WMD) and odds ratios (ORs) for continuous and dichotomous outcomes, respectively. Hypothesis-generating subgroup analyses explored ESWT type, tendinopathy classification, and symptom duration. Results Eight RCTs (458 participants) were included. No significant differences were observed between ESWT and sham groups in ΔVAS or ΔVISA-A, ΔAOFAS across follow-ups all P > 0.05). Adverse events were higher with ESWT (4.5% vs. 1.2%), though non-significant (P = 0.12). Subgroup analysis found that ESWT led to significant VAS reduction in patients with symptom duration < 12 months at 1-month (WMD: −0.76, P = 0.03) and 3-month (WMD: −1.23, P = 0.001) follow-ups than Sham ESWT. Conclusions ESWT showed no clear overall benefits compared to sham ESWT for chronic Achilles tendinopathy, but exploratory analyses hint at possible short-term pain relief for patients with symptoms lasting less than 12 months. More high-quality evidence is needed.
Ni et al. (2026) Extracorporeal shockwave therapy versus sham extracorporeal shockwave therapy for chronic Achilles tendinopathy: a meta-analysis of randomized controlled trials. PeerJ 14:e20506 https://doi.org/10.7717/peerj.20506
Analysis of molecular subtypes and prognostic signature of senescence-associated secretory phenotype in pancreatic cancer
Background Pancreatic cancer (PC) exhibits an extremely poor prognosis due to its high heterogeneity. The senescence-associated secretory phenotype (SASP), a distinct secretory profile displayed by senescent cells, has been increasingly studied. However, the role of SASP in PC prognosis and treatment remains unclear. Methods Transcriptomic sequencing data from PC patients were analyzed using consensus clustering based on SASP genes. A prognostic signature was subsequently constructed via Least Absolute Shrinkage and Selection Operator (LASSO) regression using survival-related SASP genes. Pathway enrichment analysis for distinct subgroups was performed using Gene Set Variation Analysis (GSVA). Comprehensive analyses of mutational landscapes and tumor immune microenvironments were conducted across risk-stratified PC samples. Results Consensus clustering based on SASP genes identified two SASP-associated clusters (SASPclusters), with cluster B demonstrating significantly worse prognosis than cluster A. Thirty-three SASP genes showed significant associations with PC prognosis, and a 7-gene SASP-based prognostic signature was established. High-risk patients exhibited significantly higher mutation rates. Distinct immune cell infiltration patterns, immune functions, checkpoint expression levels, and chemosensitivity profiles were observed between risk groups. Besides, we found that ANGPTL4 could promote PC cell proliferation, migration, and invasion. Conclusion Molecular subtyping and risk stratification based on SASP genes effectively predict PC prognosis and reveal heterogeneity in mutational burden, immune microenvironment, and therapeutic sensitivity. These computational findings deepen our understanding of potential role of SASP in PC and provide a theoretical foundation for personalized treatment strategies.
Kuang et al. (2026) Analysis of molecular subtypes and prognostic signature of senescence-associated secretory phenotype in pancreatic cancer. PeerJ 14:e20476 https://doi.org/10.7717/peerj.20476
A new species of aposematic grasshopper of the genus Pseudoutanacris (Acrididae: Gomphocerinae) from the Andean cloud forest of the Ecuadorian Amazon basin
We have identified a new grasshopper species belonging to the genus Pseudoutanacris Jago, 1971, in the montane forests of the eastern Andes in Ecuador. This discovery expands the known distribution of the genus, previously limited to a single species in the Bolivian tropics, by over 2,000 kilometers. For the first time, a female of the genus is described, and notes on the ecology and natural history of the species are presented. We also provide the first barcodes of the genus Pseudoutanacris Jago, 1971. The males of a newly described species, Pseudoutanacris grilla sp. nov. shares a striking coloration pattern with their Bolivian congener, Pseudoutanacris chromobapta Jago, 1971, setting them apart from other members of the tribe Amblytropidiini. However, the females maintain a cryptic coloration pattern, similar to that of the tribe members, and display different behavior from the males. During our study, we also observed Ps. grilla sp. nov. on the same plant as Megacheilacris graminicola (Descamps & Amédégnato, 1971) (Bactrophorinae: Romaleidae), a species with similar chromatic characteristics. This finding also marks the first formal documentation of the new geographical records of M. graminicola (Descamps & Amédégnato, 1971) in Ecuador.
Campos-Yánez et al. (2026) A new species of aposematic grasshopper of the genus Pseudoutanacris (Acrididae: Gomphocerinae) from the Andean cloud forest of the Ecuadorian Amazon basin. PeerJ 14:e20376 https://doi.org/10.7717/peerj.20376
Cholesterol and steroid synthesis pathways may be involved in the inhibition of osteosarcoma cell viability by calcium-sensing receptor antagonism
Background This study examined the effect of calcium-sensing receptor (CaSR) antagonism on human osteosarcoma cells and investigated the underlying molecular mechanisms of this effect through transcriptome sequencing. Methods Human osteosarcoma cell lines MG-63 and Saos-2 were treated with different concentrations (0.1–10 µM) of the CaSR antagonist NPS-2143. Cell Counting Kit-8 (CCK-8) assays were used to detect the effect of CaSR antagonism on the viability of the cells. RNA sequencing was performed on cells treated with five µM NPS-2143 for 24 hours, followed by bioinformatic analysis to identify differentially expressed genes and enriched pathways. qRT-PCR was conducted to validate key genes. Results CCK-8 assays showed that at low concentrations (0.1 and one µM), NPS-2143 had no significant effect on MG-63 and Saos-2 cell viability. At higher concentrations (five µM and 10 µM), the viability of MG-63 and Saos-2 cells was significantly reduced. Five µM was therefore selected for subsequent experiments. RNA sequencing revealed distinct gene expression profiles in NPS-2143–treated cells compared to controls. A total of 927 differentially expressed genes (DEGs) were identified in Saos-2 cells (378 upregulated, 549 downregulated), and 59 DEGs were identified in MG-63 cells (33 upregulated, 26 downregulated). Reactome and KEGG pathway enrichment analyses indicated significant enrichment of cholesterol and steroid biosynthesis–related pathways. Transcriptome sequencing showed that NPS-2143 modulated the expression of genes in cholesterol and steroid synthesis pathways. Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) confirmed that NPS-2143 promoted the expression of the cholesterol and steroid synthesis pathway genes, CYP51A1, DHCR24, LSS, and MSMO1 in MG-63 and Saos-2 cells. Discussion The inhibitory effect of NPS-2143 on MG-63 and Saos-2 osteosarcoma tumor cell viability was confirmed. CaSR antagonism significantly up-regulated genes involved in cholesterol and steroid biosynthesis, including CYP51A1, DHCR24, LSS, and MSMO1. These genes encode key enzymes in the cholesterol synthesis pathway, and their upregulation may lead to cholesterol overproduction. This may, in turn, lead to the formation of oxysterols, which are known to induce inflammation and cytotoxicity. These findings suggest a potential metabolic mechanism through which CaSR antagonists influence osteosarcoma cell viability. Although further validation is warranted, our results provide preliminary evidence implicating cholesterol biosynthesis as a mechanistic target in osteosarcoma and underscore the exploratory value of CaSR antagonists as metabolic regulators in cancer research.
Wang et al. (2026) Cholesterol and steroid synthesis pathways may be involved in the inhibition of osteosarcoma cell viability by calcium-sensing receptor antagonism. PeerJ 14:e20546 https://doi.org/10.7717/peerj.20546
The impact of physical activity on social anxiety among college students: an analysis of the chain mediation effect of family support and self-efficacy
Background This study aimed to explore the mechanisms through which physical activity affects social anxiety in college students, with a specific focus on the sequential mediating roles of family support and self-efficacy. Methods A total of 391 valid responses were analyzed using the Physical Activity Rating Scale (PARS-3), the Interaction Anxiousness Scale (IAS). Family Support Scale (PSS-Fa), and the General Self-Efficacy Scale (GSES). Mediation analyses were conducted with structural equation modeling (SEM) and bootstrapping procedures (5,000 resamples). Results Physical activity significantly predicted lower social anxiety (β = − 0.187, p < .001). Both family support (β = − 0.309, p < .001) and self-efficacy (β = − 0.390, p < .001) mediated this association, with the sequential pathway (β = − 0.073, p < .001) accounting for 13.35% of the total effect. Conclusion Physical activity was associated with lower social anxiety indirectly via higher family support and self-efficacy, while the direct effect was not statistically significant in the full mediation model. These findings provide empirical support for incorporating physical activity into university-based mental health strategies aimed at alleviating social anxiety.
Yang et al. (2026) The impact of physical activity on social anxiety among college students: an analysis of the chain mediation effect of family support and self-efficacy. PeerJ 14:e20511 https://doi.org/10.7717/peerj.20511
Development and validation of a risk prediction model for overall survival in cervical cancer patients under 50: a prospective cohort study in southwest China
Objective Accurately predicting the prognosis of cervical cancer in younger patients is increasingly important due to the rising incidence of the disease in China and the growing number of cases among individuals under 50. This study aimed to develop a nomogram to predict overall survival (OS) in cervical cancer patients under 50 in southwest China. Methods Clinicopathological and follow-up data for cervical cancer patients under 50 were prospectively collected as part of an ongoing longitudinal cohort study at Chongqing University Cancer Hospital between January 1, 2015, and May 31, 2019. A training cohort (n = 703) and a validation cohort (n = 301) were randomly selected. Variables associated with OS were assessed using a Cox regression model. Multivariate analysis was used to construct the nomogram and identify independent prognostic factors. The model’s performance was evaluated using decision curve analysis (DCA), calibration curves, area under the receiver operating characteristic curve (AUC-ROC), and the concordance index. Results The final model identified pathology, International Federation of Gynecology and Obstetrics (FIGO) staging, treatment, β2-microglobulin, neutrophil-lymphocyte ratio (NLR), and albumin as independent risk factors for OS in patients under 50. The concordance index for OS was 0.818 in the training cohort and 0.747 in the validation cohort. Calibration curves in both cohorts showed strong agreement between predicted and observed survival probabilities. In the training cohort, AUCs for 1-, 3-, and 5-year OS were 0.851, 0.847, and 0.816, respectively; in the validation cohort, they were 0.810, 0.733, and 0.730. Compared to the FIGO staging system, the nomogram demonstrated superior predictive accuracy and net benefit, as shown by the net reclassification index (NRI) and DCA. Conclusion The nomogram provides a reliable tool for predicting overall survival in cervical cancer patients under 50, supporting more personalized treatment planning.
Yuan et al. (2026) Development and validation of a risk prediction model for overall survival in cervical cancer patients under 50: a prospective cohort study in southwest China. PeerJ 14:e20509 https://doi.org/10.7717/peerj.20509
Improving taxonomic resolution, biomass and abundance assessments of aquatic invertebrates by combining imaging and DNA megabarcoding
Understanding biodiversity change requires a comprehensive assessment of not only the identity of species inhabiting an ecosystem but also their biomass and abundance. However, assessing biodiversity on the species level with precise biomass information is a time-consuming process and thus rarely applied. While DNA-based approaches like DNA barcoding offer precise species identification, they lack information on specimen size and biomass. In contrast, high-throughput imaging techniques enable rapid measurements of a specimen’s size and morphological features but may have low taxonomic resolution. In this study, we combined DNA megabarcoding, i.e., high-throughput barcoding of single specimens, with semi-automated imaging and deep neural networks to produce accurate taxonomic identifications, abundance, and biomass estimations for insects. In a multiple stressor field experiment, we collected a dataset of 743 specimens from 14 species of the orders Ephemeroptera, Plecoptera, and Trichoptera (EPT), which are routinely used as aquatic biological quality indicator taxa. Each specimen was imaged, weighed, and megabarcoded using the COI barcode gene. From the images captured using the semi-automated imaging device BIODISCOVER, we curated a final dataset of 146,439 images taken from two perpendicular cameras. We trained convolutional neural networks (CNNs) with these pictures for species identification and biomass estimation and evaluated their performance. In addition, we investigated whether models pre-trained for species identification perform better on the biomass estimation task, compared to models trained solely for biomass estimation, thus potentially reducing the need for extensive labelled data in future studies. Our findings demonstrate that combining DNA megabarcoding with automated imaging and deep neural networks enables fast, reliable, but also comprehensive assessment of species composition and biomass on the specimen level, contributing to the urgently needed methods in conservation biology, ecology, and evolution.
Rehsen et al. (2026) Improving taxonomic resolution, biomass and abundance assessments of aquatic invertebrates by combining imaging and DNA megabarcoding. PeerJ 14:e20501 https://doi.org/10.7717/peerj.20501