Finite Element Analysis of Endodontically Treated Mandibular Second Molars With Variable Root Morphologies: Endocrown vs. Post-And-Core Crown Restorations.

This study aimed to investigate the biomechanical impact of root canal anatomical variations and restoration techniques on endodontically treated mandibular second molars using finite element analysis. Five root morphologies were modelled: separated-rooted (S), fused-rooted with V-shaped (F-V), U-shaped (F-U) or Ω-shaped (F-Ω) radicular grooves and single-canal fused-rooted (F-O). Micro-CT scans were performed before and after endodontic instrumentation to generate the finite element models: intact teeth, post-and-core crowns with 2- to 3-mm ferrules and endocrowns with 3- to 4-mm pulp chamber extensions.

Tuneable multidirectional mechanical attributes of novel sectionally nonlinearly functionally graded femur and cranial bone implants with triply periodic minimal surfaces.

Sectionally nonlinearly functionally graded (SNFG) structures with triply periodic minimal surface (TPMS) are considered ideal for bone implants because they closely replicate the hierarchical, anisotropic, and porous architecture of natural bone. The smooth gradient in material distribution allows for optimal load transfer, reduced stress shielding, and enhanced bone ingrowth, while TPMS provides high mechanical strength-to-weight ratio and interconnected porosity for vascularization and tissue integration. Wherein, The SNFG structure contains sections with thickness that varies nonlinearly along their length in different patterns.

Differences in the Corneal Biomechanical Responses to LASIK and KLEx Based on Parametric Numerical Simulation.

Purpose: To use parametric numerical simulation to characterize and compare the differences in corneal biomechanical responses to laser in situ keratomileusis (LASIK) and keratorefractive lenticule extraction (KLEx) under various surgical settings.

Methods: The Finite Element Model was used in a parametric study to evaluate corneal biomechanical responses to LASIK and KLEx, considering variations in preoperative corneal thickness, corneal flap/cap thickness and diameter, refractive correction, and optical zone diameter. Surgery-induced stress, displacement, and interface contact pressure were compared between LASIK and KLEx using the Wilcoxon signed-rank test.

Directional Biomimetic Scaffold-Mediated Cell Migration and Pathological Microenvironment Regulation Accelerate Diabetic Bone Defect Repair.

Hyperglycemia-induced oxidative stress and inflammation critically impair diabetic bone defect repair. Here, a radially oriented microchannel scaffold (D-GSH@QZ) was developed via a directional freezing technique integrated with photo-cross-linking strategies. The scaffold was fabricated from gelatin methacryloyl, silk fibroin methacryloyl, and nanohydroxyapatite (HAp) to mimic the natural bone matrix, while incorporating quercetin-loaded ZIF-8 nanoparticles (Qu@ZIF-8) for pathological microenvironment modulation.

Enhanced rotator cuff tendon-bone interface regeneration with injectable manganese-based mesoporous silica nanoparticle-loaded dual crosslinked hydrogels.

Introduction: During the healing process, the functional gradient attachment of the rotator cuff (RC) tendon-bone interface fails to regenerate, which severely impedes load transfer and stress dissipation, thereby increasing the risk of retears. As a result, the treatment of rotator cuff tears remains a significant clinical challenge.

Methods: In this study, a dual-crosslinked hyaluronic acid/polyethylene glycol (HA/PEG) hydrogel scaffold was synthesized using hyaluronic acid and polyethylene glycol as base materials.

Case Report: preoperative prediction of aneurysm rupture site using aortic morphological and biomechanical analysis validated by intraoperative imaging.

Prediction of aneurysm rupture has been a great challenge for decades. We report a successful rupture site prediction on a 97 mm abdominal aortic aneurysm (AAA). A 73-year-old man with an 11-year history of AAA presented to our outpatient clinic with a one-week history of hemoptysis.

SCL15 Regulates the Release of Seed Dormancy in Arabidopsis thaliana by Integrating the Circadian Clock, Hormonal Signals and Cell Wall Remodelling.

Dormancy release and germination of the seed are two separate, but continuous phases controlled by both external (e.g., light and temperature) and internal (e.

Cathepsin K and glycosaminoglycans differentially regulate matrix metalloproteinase activity in dentin under various pH conditions.

This study examined the pH-dependent (3, 5, and 7) regulation of matrix metalloproteinase (MMP) activity by cathepsin K (catK) and glycosaminoglycans (GAGs) using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), fluorescence assays, and human dentin slice experiments. The direct effects of catK were evaluated in the catK-active, catK-deficient, and odanacatib (ODN)-inhibited groups, whereas indirect GAG/ tissue inhibitor of metalloproteinase (TIMP)-mediated regulation was assessed in the catK-active, ODN-inhibited, and chondroitin sulfate (CS)-treated groups through dimethylmethylene blue (DMMB) assays, in situ zymography, and immunofluorescence staining. CatK directly activated MMP-2 (62 kDa) and MMP-9 (82 kDa) at all pH values, with no activation observed in the ODN-inhibited or catK-deficient groups.

Dual-Mode Hybrid Discharge Plasma-Activated Injectable Hydrosol for Enhanced Immunotherapeutic Cancer Therapy.

Although cold atmospheric plasma is a promising therapeutic technique for tumor immunotherapy via reactive oxygen and nitrogen species (RONS), the challenges associated with the generation and delivery of these RONS hamper clinical adoption. Herein, a dual-mode hybrid discharge plasma-activated sodium alginate hydrosols (PAH) is proposed to enhance the antitumor immune response. Gaseous highly reactive RONS are generated by dual-mode hybrid plasma produced by mixed O and NO modes, which are converted into aqueous RONS in PAH via gas-liquid reactions between plasma and hydrosols.

HDAC3 represses Nrf2-GDF11 signaling to drive chondrocyte adipogenesis in temporomandibular joint osteoarthritis.

Introduction: Aberrant biomechanical force-induced chondrocyte adipogenesis is involved in the development of temporomandibular joint osteoarthritis (TMJ OA). Growth differentiation factor 11 (GDF11) has been implicated in this process. However, whether mechanosensitive histone deacetylase 3 (HDAC3) regulates GDF11 signaling in the context of TMJ OA remains to be elucidated.

FGF9-FGFR2 Signaling via Osteocytes-Preosteoblasts Crosstalks to Mediate Mechanotransduction-Driven Intramembranous Osteogenesis in the Underdeveloped Maxilla.

Maxillary underdevelopment is a critical component of skeletal Class III malocclusion, closely linked to altered biomechanical signaling. Mechanical stimulation through early facemask protraction can effectively promote maxillary growth, yet the underlying mechanotransduction mechanisms remain unclear. In this study, fibroblast growth factor 9 (FGF9) is identified as a key biomechanical responder in maxillary development.

Traction-regulated persistence governs durotaxis across cell types.

Cell migration toward stiffer or softer environments (durotaxis) underlies processes from development to cancer metastasis, yet the underlying mechanism and its universality remain unclear. To resolve this, we investigated how traction forces and directional persistence dictate cell migration along stiffness gradients. We utilized tunable PEG hydrogels with stiffness gradients of 1-16 kPa and perturbed contractility (blebbistatin, oligomycin), and adhesion (vinculin mutants), in cancer cells exhibiting opposing durotactic biases.

Visible-Light-Driven TiO/Pt Nanozyme-Embedded Dressings: Integrating PDT, Oxygenation, and Biomechanical Support for Pressure Ulcer Repair.

Pressure ulcer (PU) cause metabolic disorders and ischemia via prolonged pressure, leading to secondary infection, inflammation, and vascular neuropathy. However, existing therapies rely on microenvironment, HO, low repair efficiency, and lack efficient collaborative therapy. Herein, a confined multifunctional TiO/Pt nanozyme is developed via atomic layer deposition for PUs repair.

Multidimensional Regulation of Bone Marrow Niche Using Extracorporeal Shock Wave Responsive Nanocomposites for Osteoporosis Therapy.

Multidimensional modulation of the bone marrow niche represents a pivotal therapeutic strategy for bone-related disorders. However, its clinical translation remains challenging due to the inherent limitations imposed by the bone physiological barrier. Herein, a bone cavity-targeted nanocomposite (ZCD) is developed that can respond to extracorporeal shock wave (ESW), enabling triaxial regulation by inhibiting adipogenic differentiation, promoting osteogenic differentiation, and suppressing osteoclast activity.

Sagittal split ramus osteotomy-enhanced mandibular distraction osteogenesis: A biomechanically superior approach for three-dimensional reconstruction in severe micrognathia.

Background: Mandibular distraction osteogenesis (MDO) remains essential for severe micrognathia correction. The clinical adoption of conventional osteotomy techniques has been constrained by complications including non-union, inferior alveolar nerve injury, and dental germ damage, compounded by suboptimal occlusal relationships and compromised facial aesthetics. Critical considerations in MDO execution encompass neural structure preservation, osteotomy gap integrity, and achieving three-dimensional skeletal augmentation to enhance both functional stability and craniofacial proportions.

Near-Real Surgical Specimens (NRSS): A Novel Platform for Standardized Assessment of Suprachoroidal Drug Delivery.

Purpose: Suprachoroidal (SC) drug delivery is a promising avenue for treating posterior segment ocular diseases. Current ex vivo models, primarily human cadaveric eyes, are limited by tissue variability and altered post-mortem fluid dynamics. We introduce near-real surgical specimens (NRSS), an engineered ocular tissue platform, to overcome these limitations and provide standardized, reproducible evaluation of SC drug delivery.

Sagittal-oriented articular processes and intervertebral disc degeneration phenotypes can concurrently lead to an increased presence of annulus tears in the cranial adjacent motion segment : a clinical review and biomechanical simulation.

Aims: Intervertebral disc degeneration (IDD) and sagittal-oriented articular processes can restrict motility and increase stiffness of the motion segment, potentially causing compensatory stress and higher motility in adjacent segments. It is unclear if these factors trigger IDD progression in adjacent segments. This study aimed to elucidate this using functional MRI, and identify biomechanical mechanisms with a validated numerical model.

[Study on the method of estimating upper limb reachable workspace based on shoulder joint dynamic positioning].

To propose a functional method for locating the shoulder joint center of rotation aimed at rapid estimation of the upper limb reachable domain envelope, thereby informing ergonomic design and task optimization. In March 2024, shoulder kinematics during gait were recorded from ten adults using a three-dimensional motion-capture system. Assuming the existence of a point near the glenohumeral joint that maintains a fixed spatial relationship to the humerus and the acromion, we estimated both static and dynamic centers of rotation.

Mechanically tunable fiber-based hydrogel activates PIEZO1-integrin axis for enhanced bone repair.

Irregular alveolar bone defects pose persistent clinical challenges due to their complex morphology and the lack of biomaterials that simultaneously provide structural integrity, biocompatibility, and dynamic osteoinductive potential. Herein, we report a fiber-reinforced, dual-network hydrogel system (OHADN fiber@Yoda1 hydrogel) engineered to recapitulate mechanobiological cues for enhanced bone regeneration. This injectable hydrogel integrates oxidized hyaluronic acid (OHA) crosslinked with Yoda1-loaded PLGA-collagen fiber fragments and stabilized via catechol-Fe³⁺ coordination, forming a robust and self-healing structure.

Relationships between lower extremity kinematics and impact load or joint work contribution during landing in individuals with and without patellofemoral pain.

Higher lower limb impact load during landing in individuals with patellofemoral pain (PFP) is associated with increased risk of musculoskeletal injuries. This study aimed to investigate differences in landing kinematics, impact load and joint work contribution between individuals with and without PFP, and to identify relationships between kinematics and kinetics variables. Twenty-three PFP patients and nineteen healthy controls performed drop jump tests.

Flapping-wing robot achieves bird-style self-takeoff by adopting reconfigurable mechanisms.

Flying vertebrates use specialized wingbeat kinematics in hovering, takeoff, and landing, featuring ventrally anterior downstrokes and aerodynamically inactive upstrokes to enhance aerodynamic characteristics at low airspeeds. Rarely implemented in robotics, this inspired RoboFalcon2.0, a flapping-wing robot with reconfigurable mechanisms performing bioinspired flap-sweep-fold (FSF) motion for controlled bird-style takeoff.

Hemodynamic predictors of rupture in abdominal aortic aneurysms: a case series using computational fluid dynamics.

Background: Abdominal aortic aneurysm (AAA) rupture is a life-threatening event traditionally predicted by aneurysm diameter. However, many clinical observations have revealed that rupture can occur even in small aneurysms, suggesting the influence of additional biomechanical factors such as hemodynamics. The aim of this case series was to perform computational fluid dynamics (CFD) analyses based on CT scans of patients with confirmed abdominal aortic aneurysm rupture and to evaluate correlations between rupture sites and hemodynamic factors derived from simulations.

A novel three-dimensional evaluation protocol to assess the consistency of critical screw angles between preoperative planning and 3d-printed patient-specific acetabular revision prostheses.

Background: Screw fixation is pivotal for prosthetic stability. For 3D-printed customized acetabular revision prostheses designed for complex, large-scale bone defects, precise adherence to preoperative screw trajectory planning is critical. However, there remains a lack of standardized three-dimensional (3D) evaluation protocols to quantify intraoperative screw angular alignment fidelity relative to preoperative digital plans, hindering universal validation criteria.