Introduction Manipulation under anesthesia (MUA) is a non-invasive intervention commonly performed after total knee arthroplasty (TKA) for persistent knee stiffness unresponsive to conservative measures. Adjunctive strategies, including periarticular injections and regional anesthesia, have been proposed to improve pain control and outcomes following MUA. This study evaluated whether adductor canal block (ACB) at the time of MUA reduces postoperative opioid use and improves range of motion (ROM). Methods We performed a retrospective review of 83 consecutive patients undergoing MUA after TKA between October 2021 and April 2024 at a single institution. All patients after June 28, 2023 were offered ACB per an initiative set by the institution's Department of Anesthesia. Patients receiving ACB after the initiative were compared to controls prior to the initiative. Five patients were excluded (four lost to follow-up, one due to concomitant open lysis of adhesion), leaving 78 patients: 39 received ACB and 39 served as controls. Demographic variables collected included age, sex, and relevant medical comorbidities. Clinical variables comprised of time to manipulation, pre- and post-manipulation range of motion (ROM), and postoperative opioid prescription data. Results Mean time to MUA was 76.6 days after TKA; controls underwent earlier manipulation (64.2 vs 88.9 days). Pre-manipulation ROM ranged from 4.3°-84.1° in controls and 2.8°-85.5° in the ACB group. At two weeks, ROM improved to 2.5°-102.7° and 1.2°-101.8°, respectively (p=0.821). Eighteen patients (23.1%) received opioid prescriptions within 30 days, most commonly oxycodone 5 mg. Opioids were prescribed to seven (17.9%) of controls and eleven (28.2%) of ACB patients (p=0.345). Mean morphine milligram equivalents were 43.7 (S.D. 115.9) and 70.6 (122.3), respectively (p=0.225). The remaining patients did not require opioid prescriptions during the post-manipulation period. Conclusion MUA resulted in short-term ROM improvement regardless of ACB use. Although the ACB group underwent later manipulation, both groups achieved comparable gains at two weeks. ACB was not associated with reduced opioid prescribing or improved ROM, suggesting no measurable benefit in this setting.

Healthy arteries function under substantial axial prestretch (AP), the ratio of in vivo to unloaded ex vivo length. Loss of AP promotes tortuosity and disturbed hemodynamics associated with vascular pathology, yet artery-like AP has not been incorporated in vascular reconstructions, because conventional substitutes are axially stiff and cannot safely sustain physiological AP. Here, we present Axially Prestretched Elastomeric Nanofibrillar Grafts (APENGs), fabricated by ultrahigh-speed (43,000 rpm) rotational collector electrospinning of biomedical-grade polyurethane. APENGs matched native arterial axial stiffness and tolerated elastomeric elongation beyond AP = 1.5 without failure, excessive force generation, or plastic deformation, while maintaining adequate suture retention, permeability, and burst strength. In vitro, APENGs supported endothelial cytocompatibility and low hemolysis. In a bilateral swine carotid interposition model (8 grafts, two-week follow-up), experimental APENGs (nominal AP ≈ 1.5) achieved and retained elevated prestretch and reduced tortuosity relative to contralateral controls (nominal AP ≈ 1.0). Patency was 75% (prestretched) versus 100% (controls). Histology showed rapid mid-graft endothelialization, early smooth muscle ingrowth, and limited neointimal thickening near anastomoses. This study demonstrates the first synthetic graft implanted with controlled, artery-like AP, challenging the tension-free anastomosis paradigm and positioning AP as a vascular graft design lever to restore native artery biomechanics and mechanobiology. STATEMENT OF SIGNIFICANCE: Axial prestretch (AP) is an essential homeostatic state of healthy arteries that supports arterial biomechanics and mechanobiology. Reduction in AP is associated with tortuosity, disturbed flow, and maladaptive vascular responses, yet its mechanisms remain understudied. AP is absent from current grafts, which are too stiff to safely sustain physiological elongation, forcing tension-free implantation and leaving axial biomechanics unrestored. Here, we present axially prestretched elastomeric nanofibrillar grafts (APENGs), manufactured by ultrahigh-speed rotational electrospinning to achieve artery-like low axial stiffness. In a swine carotid interposition model, APENGs with controlled physiological AP demonstrated surgical feasibility, reduced tortuosity, biomimetic pulsatility, and early endothelialization. These findings challenge the tension-free paradigm and establish APENGs as a platform for restoring and studying AP-regulated vascular biomechanics and remodeling.

Although 3D cell bioprinting has emerged as a powerful strategy for engineering biomimetic skin substitutes and wound-related materials, the development of bioinks that simultaneously provide structural integrity, cytocompatibility, and bioactivity remains challenging. In this work, gelatin methacryloyl (GelMA)-based hydrogels incorporating tannic acid (TA) were developed and processed via digital light processing to fabricate 3D scaffolds as prototype platforms for skin-related applications. The incorporation of TA significantly enhanced hydrogel stability, mechanical stiffness, and antibacterial activity, while maintaining high water content and improving print fidelity. Structural characterization by SEM and micro-CT revealed that TA promoted the formation of a more compact and homogeneous porous network, consistent with increased storage modulus, improved compressive strength and delayed degradation under physiological conditions. Rheological analysis confirmed that GelMA+TA systems exhibit enhanced viscoelastic stability and resistance to deformation. Sustained TA release over 25 days endowed the scaffolds with antibacterial activity against E. coli and S. aureus. Importantly, 3D bioprinting and encapsulation studies demonstrated cell-type-dependent biological responses. Human skin fibroblasts exhibited robust long-term viability and proliferation within pure GelMA scaffolds, while TA-containing hydrogels promoted early cell-material interactions and fibronectin deposition but were associated with reduced long-term fibroblast proliferation, suggesting a dose- and exposure-dependent effect of TA. In contrast, Vero cells, used as a model epithelial cell line, showed improved viability and morphology under encapsulation conditions in GelMA+TA scaffolds. These results highlight the critical interplay between macromolecular composition, 3D microenvironment, and cell response, demonstrating that GelMA+TA systems represent a promising preliminary platform for the development of tunable bioactive scaffolds for wound-related applications.

Muscle stretching is widely applied to increase the range of motion and modulate muscle stiffness, partly due to stress-relaxation mechanisms during sustained elongation. This study investigated the acute effects of a 3-minute static stretching protocol on the shear modulus (μ) of the superficial and deep layers of the lumbar multifidus muscle and examined inter-individual variability in stiffness responses. Twenty-two healthy men (23.1 ± 3.9 years) participated. Shear modulus was assessed using shear wave elastography at baseline, immediately after, and 5 min following stretching, as well as continuously during a 3-minute static trunk flexion stretching. Functional flexibility was evaluated using the Schober and Wells tests, and inter-individual variability was explored using K-means clustering. Significant improvements in functional flexibility were observed after stretching (Schober: p < 0.001; Wells: p = 0.004), whereas no significant changes in μ were detected at the group level. However, an exploratory cluster analysis two distinct response patterns: responders exhibited a progressive reduction in stiffness during stretching, whereas non-responders showed an increase in stiffness. These divergent temporal responses are consistent with viscoelastic behavior such as stress-relaxation, but may also reflect differences in neuromuscular activation and stretch tolerance. Overall, these findings indicate that a 3-minute static stretching protocol improves functional flexibility without altering lumbar multifidus stiffness at rest, suggesting that the flexibility gains are not explained solely by changes in multifidus stiffness. They also highlight substantial inter-individual variability in mechanical responses, which should be considered when interpreting stretching interventions.

Bladder function is assessed through pressure-volume relations, compliance indices and flow measurements, while structural evaluation relies primarily on qualitative imaging descriptors. These approaches do not formally quantify how bladder geometry evolves during filling. To distinguish structural reorganization from pure mechanical stiffness, we developed a simulation-based topological analysis of bladder filling grounded in mechanical parameters derived from the literature. Progressive filling was modeled under quasi-static conditions, generating multi-volume geometries from which spatial descriptors were computed. Inspired by the Freudenthal suspension theorem, filling was interpreted as a dimensional expansion process, while structural stability was evaluated by examining whether geometric invariants remain preserved across increasing volumes. Simulated smooth expansion and controlled structural perturbations were compared under identical loading conditions. We found that pressure trajectories and wall stress estimates were similar across configurations when compliance was matched, whereas geometric descriptors exhibited divergent volume-indexed stability profiles in the presence of remodeling. Computable instability measures detected progressive spatial heterogeneity despite preserved global pressure behavior. Providing quantitative measure of geometric continuity across successive filling states, our approach suggests that structural remodeling becomes detectable before conventional functional impairment is apparent. Progressive surface irregularity can emerge even when compliance, detrusor pressure and flow parameters remain within reference limits. In addition, serial imaging over time may reveal increasing instability in shape organization across filling cycles, allowing identification of individuals at higher risk of diverticula formation, functional decompensation or structural complications despite stable pressure measurements.

The descending thoracic aorta (DTA) is a crucial large blood vessel, and its inherent mechanical properties are fundamental to cardiovascular system stability. This study provides a pilot characterization of the biaxial mechanical behavior and microstructural features of the porcine DTA through biaxial tensile testing and histopathological analysis. The porcine DTA exhibited pronounced nonlinear hyperelastic behavior characterized by marked anisotropy: higher compliance in the longitudinal direction and greater stiffness in the circumferential direction. The experiment also found that the porcine DTA exhibited progressive mechanical damage beyond 40% strain, as evidenced by stress softening across loading cycles. Three hyperelastic constitutive models-the classical two-fiber-family HGO model, the fiber-dispersion Holzapfel model, and the four-fiber polynomial model-were evaluated for their ability to characterize the DTA mechanical response. All three models captured the essential anisotropic and nonlinear features, with performance generally increasing with model complexity. Cross-validation on independent strain ratios confirmed predictive robustness across all models. This study advances understanding of the mechanical properties and load-induced microstructural response of the porcine DTA, provides comparative validations for constitutive models with differentiated prediction accuracy and computational complexity, and establishes a foundation for computational modeling applications.

Protein-polysaccharide interactions play a central role in structuring food hydrogels, yet how anionic polysaccharides induce spatial organization in lipoprotein fibril systems remains unclear. Here, pectin was incorporated into egg yolk high-density lipoprotein (HDL) fibril hydrogels to investigate polysaccharide-driven microphase separation and its effects on network architecture. The anionic backbone of pectin promoted competitive intermolecular interactions, strengthening electrostatic attraction and hydrogen bonding while weakening hydrophobic interactions and disulfide bonding. These shifts triggered microphase separation, resulting in heterogeneous yet interconnected gel networks. Consequently, gels exhibited enhanced stiffness, strain-dependent structural rearrangement, and improved energy dissipation. Water redistribution toward more immobilized states and increased thermal stability further supported the formation of constrained hierarchical structures. Overall, this study identifies microphase separation as a key molecular mechanism governing structure-function relationships in HDL fibril hydrogels and advances the understanding of polysaccharide-mediated network organization in food biopolymer systems.

Higher diastolic aortic pressure is associated with central arterial elastic recoil function and may help preserve peripheral perfusion. Japanese female pearl divers, called "Ama," exhibit lower arterial stiffness as an adaptation to lifelong repeated diving, but whether this translates into enhanced diastolic blood flow remains unclear. This study investigated aortic and carotid hemodynamic profiles to determine whether female pearl divers demonstrate enhanced diastolic blood flow in association with diastolic aortic pressure. A total of 61 middle-aged and elderly female pearl divers (<65-years group: n=23, 53 ± 9 years; ≥65-years group: n=38, 72 ± 4 years, representing middle-aged and older groups, respectively) and 94 female non-divers (<65-years group: n=48, 53 ± 9 years; ≥65-years group: n=46, 73± 5 years) were studied. Aortic pressure was estimated from applanation tonometry carotid arterial pressure waveforms via general transfer function. Carotid blood flow was calculated from blood velocity and diameter of the common carotid artery. Diastolic aortic pressure-time integral and carotid flow volume were calculated as areas under the waveforms from the dicrotic notch to end-diastole. Compared with non-divers, pearl divers exhibited a higher diastolic aortic pressure-time integral (main effect of group, P<0.01). Moreover, diastolic carotid blood flow volume was also greater in peal divers than in non-divers (main effect of group, P<0.01). Therefore, compared with female non-divers, lifelong female pearl divers may have lower central arterial stiffness that enhances diastolic aortic pressure, thereby preserving greater carotid blood flow during diastole.

Atrial fibrillation is associated with a high risk of thromboembolic events, often mitigated by left atrial appendage occlusion (LAAO) when anticoagulation is contraindicated. This study presents a patient-informed computational workflow integrating pre-operative computational fluid dynamics (CFD), finite element (FE) modeling of device deployment, and post-operative CFD informed by the FE-deformed configuration. A proof-of-concept case was analyzed considering three atrial wall stiffness values to explore biomechanical variability. Pre-implant CFD simulations identified regions of blood stasis within the left atrial appendage, highlighting areas of thrombotic risk. FE simulations of device deployment demonstrated that wall stiffness influenced device positioning, orientation, and contact with the atrial anatomy. Post-implant CFD analyses, incorporating both the FE-informed device configuration and two fabric reconstruction strategies (conformal vs. detached), revealed flow redirection and changes in wall shear stress consistent with effective occlusion and the impact of fabric variability. Overall, the proposed workflow enabled a coherent assessment of mechanical and hemodynamic outcomes, providing insights into how anatomical and biomechanical factors affect post-operative LA hemodynamics. This multiphysics approach offers a step toward a patient-informed computational framework for assessing device deployment and thrombogenic risk under complete occlusion conditions.