Sustainable aviation fuel (SAF) deployment is commonly judged by blend percentage, although blend fraction alone does not determine climate cost-effectiveness. This study retains a transparent plant-to-passenger framework that propagates SAF production economics through blend pricing, flight expenditure, annual airline exposure, passenger-normalized burden, lifecycle CO(2)e reduction, average abatement cost, and carbon-value break-even. The linear benchmark shows that when unit fuel price and lifecycle emission factor are independent of deployment scale and mix linearly with SAF fraction, average abatement cost is mathematically blend-invariant; this identity is treated as a baseline property of the accounting model rather than as a paradox or stand-alone novelty. The operational analysis is now anchored to the current 50% ASTM D7566 HEFA-SPK blend limit, with higher fractions used only as explicitly notional extensions where retained. At 50% SAF, the reference market case adds USD 3250 per flight and USD 15.29 per effective passenger while avoiding 6.50 tCO(2)e per flight; the average abatement cost remains USD 500 tCO(2)e(-1). The reference production model retains an LCOSAF of USD 2355 t(-1), while additional boundary tests show where the linear identity ceases to hold: a bounded feedstock-supply response that raises feedstock price by 15% at 50% blend increases modeled LCOSAF to about USD 2532 t(-1) and average abatement cost to USD 628 tCO(2)e(-1). A coupled lifecycle sensitivity links yield, hydrogen carbon intensity, and electricity carbon intensity to the same production scenarios, co-product accounting is tested using revenue-credit, economic-allocation, and energy-allocation treatments, and Sobol indices confirm feedstock price, yield, and CAPEX as the dominant variance contributors. The resulting framework preserves the original plant-to-passenger transmission logic while distinguishing deployment scale from costeffectiveness, identifying the assumptions that break linear blend invariance, and placing the cost-carbon results in a certification and policy context relevant to aviation deployment.
Conventional potential field (PF) methods for unmanned aerial vehicle (UAV) navigation often fail in dynamic environments, particularly when obstacles and targets move with acceleration. In such cases, the repulsive forces generated by conventional PF approaches are insufficient, leading to oscillations, delayed responses, or even collisions. This paper presents an acceleration-based potential field (AB-PF) method designed to address these limitations by incorporating acceleration terms of both the UAV and the obstacles directly into the repulsive potential formulation. The resulting controller anticipates obstacle motion more effectively, enabling smoother avoidance and faster convergence to the desired path. The proposed method is validated experimentally using multiple UAV scenarios, including circular, infinity-shaped, and helical trajectories, with both static and accelerated obstacle drones. Performance is evaluated using key metrics: trajectory tracking error; root mean square error (RMSE), minimum and average separation distances, convergence time, and peak acceleration. Results demonstrate that AB-PF consistently outperforms conventional PF and Fuzzy-PF approaches. On average, AB-PF reduces RMSE by 25%–40%, increases separation distances by 15%–30%, and decreases convergence time by 20%–35%, while requiring up to 25% lower peak acceleration. These findings confirm that AB-PF improves both safety and dynamic smoothness in UAV motion planning, making it a promising strategy for real-time navigation in complex environments with accelerated obstacles.
Abstract A hybrid system of near surface–mounted carbon fiber–reinforced polymer (NSM-CFRP) and externally bonded CFRP has proven efficiency in improving and recovering the structural performance of the undamaged and damaged structural elements, especially when used for the RC flat slabs. The main objective of this research was to propose strengthening and repairing techniques to enhance the punching shear performance of RC flat slabs. Specifically, a hybrid system of CFRP ropes embedded through an intact and preloaded RC flat slab surface and then anchored by CFRP sheets was used to investigate its efficiency in enhancing and restoring the structural properties of the undamaged and damaged flat slabs. Nine square RC flat slabs with 1,000-mm side length and 120-mm width were cast using normal-weight concrete with a compressive strength of about 26 MPa. The specimens were used as follows: one specimen was used as a control specimen, four specimens were strengthened using vertical and inclined CFRP ropes embedded through the flat surface anchored by CFRP sheets, and four specimens were preloaded up to 50% of the ultimate capacity of the control specimen and then repaired using vertical and inclined CFRP ropes embedded through the flat surface anchored by CFRP sheets. Test results indicated that the use of a hybrid system can improve the structural performance and punching shear behavior of RC flat slabs, whether undamaged ones or damaged by preloading. Additionally, the most effective strengthening technique in terms of improving the ultimate capacity of the flat slab was to apply the CFRP ropes inside the concrete surface vertically on both punching perimeters anchored by CFRP sheets; with this system, the ultimate capacity increased by 66.2%, whereas applying the same strengthening technique on the first punching perimeter only increased the stiffness, by 23.2%. The same performance was observed for the preloaded specimens, but when applying the rope with an inclination inside the flat slab, the percentage increase in the ultimate capacity when applying the repairing technique on both punching perimeters was 84.4%, and 14.2% increase was recorded in stiffness when applying the repairing technique on the first perimeter only. The use of the hybrid repairing and strengthening technique contributed to enhancing the failure mode performance of the flat slab; all specimens exhibited a debonding failure of the CFRP sheets, followed by a concrete cover separation.
Chiari malformation type 1 (CM-1) is traditionally defined by tonsillar herniation, yet clinical symptoms often correlate poorly with simple linear measurements. Emerging research suggests that the geometry of the fourth ventricle may reflect deeper developmental anomalies. This study aimed to evaluate the association between fourth ventricular roof angle (FVRA) geometry and brainstem dysfunction and to determine its utility as a prognostic marker for symptomatic presentation and surgical outcomes. Following PRISMA guidelines and PROSPERO registration (CRD420261301268), a systematic search of Medline, Scopus, Web of Science, and Embase was conducted through January 2026. Studies reporting FVRA and BSD outcomes (apnea, dysphagia, cranial nerve deficits) were included. Statistical analysis was performed using the meta package in R (Version 4.1.0). A random-effects model was employed to calculate pooled Odds Ratios (OR) and 95
Glioblastoma (GBM) remains a lethal malignancy characterized by therapeutic resistance and recurrence. Emerging evidence suggests that senescent niches may shape tumor progression, support tumor stemness, and modulate immune engagement. We integrated transcriptomic data from the Glioma Longitudinal Analysis Consortium (GLASS; 118 primary and 113 recurrent IDH-wildtype GBM samples) with protein-level analysis from an independent cohort of 37 GBM patients (25 primary, 12 recurrent), including 6 matched primary-recurrent pairs. Senescence-, stemness-, and immune-related pathways were assessed using single-sample gene set enrichment analysis (ssGSEA), while immunohistochemistry quantified the expression of Lamin B1, Ki67, p53, SOX2, HLA-DRA, B2M, and CD56. Transcript-level validation was performed using matched-pair Wilcoxon testing in 101 GLASS pairs. Recurrent tumors demonstrated increased enrichment of senescence-associated transcriptional programs, including upregulated KAMMINGA_SENESCENCE and reduced TANG_SENESCENCE_TP53_TARGETS_DN scores. Lamin B1 and Ki67 protein levels were significantly lower in recurrent tumors (p = 0.004 and p = 0.016), while p53 expression increased overall (p = 0.001), suggestive of a senescence enrichment upon recurrence. In the matched analysis (6 pairs; 12 samples total), Lamin B1 and Ki67 generally trended lower at recurrence, although paired differences were not statistically significant. SOX2 expression remained broadly stable at the protein level but showed a modest decrease in RNA expression. Immune markers (HLA-DRA, B2M, CD56) exhibited minimal differences, although HLA-DRA increased significantly overall at recurrence (p = 0.025). Matched transcriptomic analysis in GLASS pairs supported recurrent-specific reductions in LMNB1, MKI67, and SOX2, with no consistent changes in TP53, HLA-DRA, B2M, or NCAM1. Recurrent IDH-wildtype GBM exhibits a transcriptional and protein expression shift towards a senescence-associated state with no concomitant changes in SOX2 and select immune markers.
