It pays to follow the leader: Metabolic cost of flight is lower for trailing birds in small groups.

Many bird species commonly aggregate in flocks for reasons ranging from predator defense to navigation. Available evidence suggests that certain types of flocks-the V and echelon formations of large birds-may provide a benefit that reduces the aerodynamic cost of flight, whereas cluster flocks typical of smaller birds may increase flight costs. However, metabolic flight costs have not been directly measured in any of these group flight contexts [Zhang and Lauder, J. Exp. Biol. 226, jeb245617 (2023)]. Here, we measured the energetic benefits of flight in small groups of two or three birds and the requirements for realizing those benefits, using metabolic energy expenditure and flight position measurements from European Starlings flying in a wind tunnel. The starlings continuously varied their relative position during flights but adopted a V formation motif on average, with a modal spanwise and streamwise spacing of [0.81, 0.91] wingspans. As measured via CO2 production, flight costs for follower birds were significantly reduced compared to their individual solo flight benchmarks. However, followers with more positional variability with respect to leaders did less well, even increasing their costs above solo flight. Thus, we directly demonstrate energetic costs and benefits for group flight followers in an experimental context amenable to further investigation of the underlying aerodynamics, wake interactions, and bird characteristics that produce these metabolic effects.

Marital Status Independently Predicts Mortality in Adult Patients with Craniopharyngioma: A SEER-Based Study.

BACKGROUND: The relationship between marital status and overall survival (OS) in adult patients with craniopharyngioma has not been explored in depth. We aimed to elucidate the impact of marital status on the prognosis of craniopharyngioma patients excluding bias from baseline demographics and treatment. METHODS: We extracted 1539 patients diagnosed with craniopharyngioma between 2000 and 2019 from the Surveillance, Epidemiology, and End Results database and divided patients into 4 marital subgroups: married, single, divorced/separated, and widowed. Kaplan-Meier curves with a log-rank test were used to discern differences in OS between marital subgroups. Univariate and multivariate Cox regression were used to identify independent prognostic factors of mortality. RESULTS: There were 1539 eligible patients: 863 (56.1%) were married, 466 (30.3%) were single, 135 (8.8%) were divorced/separated, and 75 (4.9%) were widowed. Widowed patients had the worst mean OS, 5-year OS and 10-year OS at 84.2 months, 58.0% and 26.9%, respectively. After stratifying patients by age, our multivariate analysis showed that marital status was an independent predictor of mortality in middle-aged craniopharyngioma patients (40-60 years, P < 0.001), but not in young adults (18-39 years, P = 0.646) or elderly patients (>60 years, P = 0.076). Among middle-aged patients, single (hazard ratio 1.72, confidence interval 1.19-2.47, P = 0.004) and divorced/separated patients (hazard ratio = 2.29, confidence interval = 1.49-3.54, P < 0.001) showed a higher risk of mortality compared to married patients (reference). CONCLUSIONS: Marital status is an independent prognostic factor predicting OS for middle-aged patients with craniopharyngioma. Providing additional social and psychological support for single and divorced/separated patients may improve outcomes for this vulnerable population.

Gross total resection and survival outcomes in elderly patients with spinal chordoma: a SEER-based analysis.

Objective: The association between aggressive resection and improved survival for adult spinal chordoma patients has not been well characterized in the geriatric population. Thus, the present study aimed to elucidate the relationship between gross total resection (GTR) and survival outcomes for patients across different age groups. Methods: The authors isolated all adult patients diagnosed with spinal chordoma from the 2000-2019 Surveillance, Epidemiology, and End Results database and divided patients into three surgical subgroups: no surgery, subtotal resection (STR), and GTR. Kaplan-Meier curves with a log-rank test were used to discern differences in overall survival (OS) between surgical subgroups. Univariate and multivariate analyses were used to identify prognostic factors of mortality. Results: There were 771 eligible patients: 227 (29.4%) received no surgery, 267 (34.6%) received STR, and 277 (35.9%) received GTR. Patients receiving no surgery had the lowest 5-year OS (45.2%), 10-year OS (17.6%), and mean OS (72.1 months). After stratifying patients by age, our multivariate analysis demonstrated that patients receiving GTR aged 40-59 (HR=0.26, CI=0.12-0.55, p<0.001), 60-79 (HR=0.51, CI=0.32-0.82, p=0.005), and 80-99 (HR=0.14, CI=0.05-0.37, p<0.001) had a lower risk of mortality compared to patients undergoing no surgery. The frequency of receiving GTR also decreased as a function of age (16.4% [80-99 years] vs. 43.2% [20-39 years]; p<0.001), but the frequency of receiving radiotherapy was comparable across all age groups (48.3% [80-99 years] vs. 45.5% [20-39 years]; p=0.762). Conclusion: GTR is associated with improved survival for middle-aged and elderly patients with spinal chordoma. Therefore, patients should not be excluded from aggressive resection on the basis of age alone. Rather, the decision to pursue surgery should be decided on an individual basis.

Mediated Electrochemical Probing: A Systems-Level Tool for Redox Biology.

Biology uses well-known redox mechanisms for energy harvesting (e.g., respiration), biosynthesis, and immune defense (e.g., oxidative burst), and now we know biology uses redox for systems-level communication. Currently, we have limited abilities to "eavesdrop" on this redox modality, which can be contrasted with our abilities to observe and actuate biology through its more familiar ionic electrical modality. In this Perspective, we argue that the coupling of electrochemistry with diffusible mediators (electron shuttles) provides a unique opportunity to access the redox communication modality through its electrical features. We highlight previous studies showing that mediated electrochemical probing (MEP) can "communicate" with biology to acquire information and even to actuate specific biological responses (i.e., targeted gene expression). We suggest that MEP may reveal an extent of redox-based communication that has remained underappreciated in nature and that MEP could provide new technological approaches for redox biology, bioelectronics, clinical care, and environmental sciences.