Journal of the Mechanical Behavior of Biomedical Materials

Digital volume correlation (DVC) has become the benchmark experimental technique for full-field strain measurement in bone mechanics. In our previous work we developed a novel data-driven image mechanics (D2IM) approach that learns from DVC data and predicts displacement fields directly from undeformed X-ray computed tomography (XCT) images, deriving strain fields from such predictions. However, strain fields derived through numerical differentiation of displacement fields amplify high-frequency noise, and regularization techniques compromise spatial resolution while incurring substantial computational costs. Here we propose the upgrade D2IM-Strain to predict strain fields directly from XCT images of bone. Two prediction strategies were compared: displacement-derived strain and direct strain prediction. The direct strain prediction model significantly improved accuracy particularly for strain magnitudes below 10000{micro}{varepsilon}, taken as a representative threshold value for bone tissue yielding in compression. In addition, the direct approach reduced false-positive high-strain classifications by 75%. By eliminating numerical differentiation, the approach reduces noise amplification while maintaining computational efficiency. These findings represent a critical step toward developing robust data-driven volume correlation methods for hierarchical materials.

The effects of specific footwear features on biomechanical parameters are often confounded by simultaneous changes in other shoe conditions, making it difficult to identify the isolated effect of material and design properties on relevant biomechanical outcomes. This study aimed to propose a tool, namely the Modular Footwear Setup (MFS), to assess the effects of midsole modifications on lower limb joint kinematics and in-shoe plantar pressure. The MFS uses a micro-hook-and-loop fastening system and a custom alignment device to enable fast, strong, and reliable midsole attachment/detachment to/from the upper. Accuracy and repeatability of the MFS in replicating the biomechanical outcomes of a control shoe featuring the same upper and midsole were tested in 10 healthy participants (5M,5F; age=33.2{+/-}9.2 yrs; BMI=21.5{+/-}2.8 kg/m2). Participants were asked to walk wearing both the MFS and the standard control shoe in three sessions. Kinematics of lower limb joints were measured via inertial measurement units, while capacitive pressure insoles were used to measure in-shoe plantar pressure. Intraclass correlation coefficient (ICC) was used to assess the repeatability of kinematic and pressure measurements between sessions. Statistical Parametric Mapping analysis did not identify significant differences in joint kinematics between conditions. While the MFS exhibited slightly lower peak pressure at the rearfoot, pressure parameters were not statistically different in the other foot regions. The MFS demonstrated good-to-excellent inter-session repeatability (ICC 0.84-0.97) for peak and mean pressure. Participants reported similar levels of comfort and stability in both shoes. The findings of the present study suggest the MFS has the potential to be a reliable and accurate tool for evaluating the effect of midsole features on relevant biomechanical parameters. This modular approach may improve data-driven footwear design by providing a consistent platform for testing the effects of midsole designs and materials across various applications, including therapeutic, safety, and athletic shoes.

Spectral similarity is often judged with a single metric such as RMSE, yet this can be misleading: physically different errors can produce similar scores. This is a critical limitation for computational biomechanics, where spectral agreement underpins both model validation and machine-learning loss design. Here, we develop a multi-metric framework for objective spectral biofidelity and test whether it better captures meaningful disagreement across complex frequency-domain responses. We evaluated 12 complementary similarity metrics, including CORA and ISO/TS 18571, using controlled spectral perturbations that mimic common real-world deviations such as resonance shifts, localized spikes, and broadband tilts. We then applied the framework to an SBI-tuned finite-element middle-ear model to assess convergence with training dataset size and robustness to measurement noise across repeated stochastic runs. No single metric performed reliably across all distortion types. Shape-based metrics tracked resonance morphology but could miss vertical scaling, whereas MaxError remained important for narrowband anomalies that smoother metrics underweighted. CORA and ISO 18571 did not consistently outperform simpler metrics. Rank aggregation using Borda count provided a robust consensus across metrics, enabling objective identification of training-data saturation and noise thresholds beyond which similarity rankings became unstable. These results show that spectral biofidelity cannot be reduced to a single norm. A multi-metric consensus provides a clearer and more physically meaningful basis for comparing experimental and simulated spectra, and offers a more defensible foundation for data-fidelity terms in physics-informed and simulation-based machine learning.

Intervertebral disc degeneration (IVDD) compromises disc structures and mechanics, yet systematic evaluations of the mechanical responses and their relationship to morphological changes in preclinical models remain limited. This systematic review and meta-analysis synthesized mechanical and morphological alterations following experimental disc injury in in vivo animal models. Searches of MEDLINE, EMBASE and Web of Science databases were conducted in accordance with PRISMA guidelines. Study quality and risk of bias were assessed using modified CAMARADES and SYRCLE tools. Twenty-eight studies were included. Pooled analyses showed significant reductions in stiffness, Youngs modulus, and disc height, and significant increases in range of motion and degeneration grade, indicating both mechanical and structural deterioration. Youngs modulus appeared to be the most sensitive marker of functional degeneration. By contrast, creep and other viscoelastic responses showed non-significant changes. High heterogeneity was evident across studies, reflecting variability in injury models, species, timepoints, and testing methods. Evidence of publication bias was detected in several domains, and moderate methodological quality was noted with overall insufficient blinding and lack of sample size calculations. In vivo animal models of IVDD demonstrate robust and consistent mechanical and morphological degeneration after injury. Youngs modulus is a sensitive mechanical indicator, supporting its use in future preclinical research. Standardization of outcome definitions, methodology, and reporting is essential to improve comparability and enhance translation of preclinical findings to clinical research.

The osteochondral junction is a specialized region ensuring the biomechanical and biological integration of the unmineralized articular cartilage with the subchondral bone through an intermediate layer of mineralized cartilage. This location is of clinical relevance, being the target of osteoarthritis. While aging is considered a risk factor for osteoarthritis, the interplay between microstructural and material changes during aging and predisposing to joint degeneration is not fully clear. This is especially true for mineralized cartilage, which remains understudied despite its critical role in load transfer from unmineralized articular cartilage to bone. We investigate age-related alterations of mineralized cartilage and subchondral bone in rat tibiae of adult and aged animals using a multimodal, high-resolution, correlative analysis. Our approach includes micro-computed tomography to measure microstructural features, second harmonic generation imaging to visualize collagen organization, quantitative backscattered electron imaging to map local mineral content, and nanoindentation to obtain mechanical properties. Mineralized cartilage and subchondral bone exhibited distinct age-related modifications. At the architectural level, the subchondral plate thickened and the trabecular network became coarser, those changes being different from those observed in the metaphysis. At the tissue level, mineralized cartilage was less mineralized than bone but exhibits a greater relative increase of mineral content with age, underlying differences in mineralization. A central observation is that aging led to an abrupt transition in mineral content and mechanical properties across the interface between unmineralized and mineralized cartilage, with a conceivable impact on stress localization. Overall, these changes may alter load transfer and contribute to age-related joint degeneration.

IntroductionTrabecular bone exhibits brittle behaviour governed by microscale deformation and damage processes, yet quantitative characterisation of crack progression remains challenging because classical fracture mechanics approaches do not apply to architecturally discontinuous porous tissues. This study evaluates whether synchrotron X-ray computed tomography (XCT) combined with digital volume correlation (DVC) can provide a practical experimental approach for quantifying crack opening behaviour in human trabecular bone. MethodSemicylindrical specimens harvested from femoral heads of hip-fracture donors (n = 5) and non-fracture controls (n = 5) underwent stepwise three-point-bending during XCT imaging. Full-field displacement maps enabled direct measurement of crack mouth opening displacement (CMOD), crack length (a), and their ratio, CMOD/a, used here as a geometry-normalised comparative descriptor of brittle response. Automated crack segmentation using phase-congruency crack detection (PCCD) was compared against manual measurements. ResultsXCT-DVC successfully resolved three-dimensional displacement discontinuities during crack initiation and propagation in all specimens. Hip-fracture donors exhibited significantly lower critical crack-opening ratios (CMOD/a)* than Controls (0.31 vs 0.47; p = 0.008) and reached mechanical instability at lower applied loads, consistent with a more brittle structural response under this test configuration. Despite these differences, total crack extension ({Delta}a*) was similar between groups. Automated crack tracking using phase-congruency-based segmentation showed excellent agreement with manual measurements (r{superscript 2} = 0.98), confirming reliable extraction of crack geometry from DVC displacement fields. DiscussionThese results indicate that XCT-DVC can provide a practical approach for quantifying crack-opening behaviour in trabecular bone when classical fracture-mechanics parameters are not applicable in anatomically constrained specimens. The reduced critical crack-opening ratios and earlier instability observed in Hip-fracture donors are consistent with a more brittle comparative mechanical response that is not captured by crack extension alone. The strong agreement between automated and manual crack measurements further supports displacement-based descriptors as reliable comparative indicators of brittle behaviour in porous, architecturally discontinuous tissues. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=76 SRC="FIGDIR/small/714043v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@31c5d7org.highwire.dtl.DTLVardef@1b3d9a4org.highwire.dtl.DTLVardef@95df7borg.highwire.dtl.DTLVardef@1834216_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical abstractC_FLOATNO C_FIG

Background: Peak height velocity (PHV) is a critical indicator of pubertal growth timing and is widely used in orthodontics to determine optimal timing for growth modification interventions. Secular trends toward earlier maturation have been reported, but a quantitative synthesis of PHV age reduction across generations is lacking. Objective: To systematically review and quantitatively synthesize evidence for secular trends in age at PHV and to estimate the pooled mean difference in PHV age between historical and contemporary cohorts. Methods: A systematic search was conducted in PubMed and Google Scholar from January 1990 to December 2021. The Directory of Open Access Journals (DOAJ) was also searched but yielded no eligible studies due to the specificity of the search string. Studies were included if they reported age at PHV in two or more birth cohorts separated by at least 20 years, used objective methods to determine PHV (longitudinal growth data with curve fitting), and reported means with standard deviations or standard errors. Risk of bias was assessed using the Newcastle-Ottawa Scale. A random-effects quantitative synthesis (meta-analytic approach) was performed to calculate the pooled mean difference in PHV age between historical and contemporary cohorts. Between-study variance (tau-squared) was estimated using the restricted maximum likelihood (REML) method. Heterogeneity was assessed using I-squared statistics. Given the limited number of eligible studies, findings should be interpreted as preliminary. Results: Two high-quality longitudinal studies met inclusion criteria, comprising 171 participants from historical cohorts (1969-1973) and 71 participants from contemporary cohorts (1996-2000). The pooled mean difference in PHV age was -0.48 years (95% CI: -0.72 to -0.24, P < 0.001), indicating that contemporary children reach PHV approximately 0.5 years earlier than their historical counterparts. PHV velocity showed a pooled increase of 0.71 cm/year (95% CI: 0.48 to 0.94, P < 0.001). Heterogeneity was low (I-squared = 0% for both analyses). Both studies were rated as low risk of bias. These findings are based on a limited number of studies and should be interpreted as preliminary. Conclusions: This preliminary quantitative synthesis provides evidence of a secular decline in age at peak height velocity of approximately 0.5 years in contemporary children compared to historical cohorts, accompanied by an increase in growth velocity. These findings suggest that orthodontic growth modification strategies may need to be initiated earlier than traditionally recommended. However, given the limited evidence base, results should be interpreted with caution and require confirmation in large-scale longitudinal studies.

The clitoris is one of the least studied organs of the human body. The detailed anatomy of the clitoris is challenging to address through a gross dissection, as most of its parts are embedded internally, surrounded by pubic bone and several pelvic organs. While clinical imaging methods such as magnetic resonance imaging can capture the gross 3D morphology, they lack the spatial resolution required to resolve the detailed structures. In this study, we generated micron-scale computed tomography images of the female pelvises, leveraging a synchrotron radiation X-ray source. This unique data revealed the complex trajectory of the dorsal nerve of the clitoris, the main sensory nerve of the clitoris. Notably, the nerve trunks within the clitoral glans were revealed, with the maximum diameter ranging from 0.2 to 0.7 mm. They showed a tree-like branching pattern projecting towards the surface of the glans. We also revealed that some branches of the dorsal nerve of the clitoris ramify to innervate the clitoral hood and mons pubis. Finally, the posterior labial nerve, a branch of the perineal nerves, was shown to innervate the surroundings of the clitoris and the labial structures. These findings have an immediate impact on operations performed around the vulva area, such as gender-affirmation surgery and reconstruction surgery after genital mutilation.

Background: Incisor extraction represents a strategic yet underutilized orthodontic treatment modality for managing anterior discrepancies. Despite its clinical relevance, the evidence base has not been systematically synthesized with meta-analytic techniques. Objective: To systematically review and meta-analyze the evidence on incisor extraction in orthodontic treatment, evaluating clinical outcomes and biomechanical efficacy in both maxillary and mandibular arches. Methods: A comprehensive search of open-access electronic databases (PubMed, LILACS, SciELO, Google Scholar, DOAJ, OpenGrey) and orthodontic journal archives was conducted from inception to January 11, 2026 following PRISMA guidelines. Eligible studies included randomized controlled trials, prospective cohort studies, and retrospective cohort studies with greater than or equal to 10 patients reporting quantitative outcomes following incisor extraction or incisor movement with premolar extraction. Primary outcomes included space closure efficiency, incisor position changes, root resorption, and stability. Risk of bias was assessed using ROBINS-I for observational studies and Cochrane RoB 2.0 for RCTs. Certainty of evidence was evaluated using GRADE. Results: From 1,842 identified records, 20 primary studies met inclusion criteria (4 RCTs, 16 observational studies), comprising 1,347 patients. Sixteen studies provided data for meta-analysis. With moderate-certainty evidence, mandibular incisor extraction (8 studies, n=412) demonstrated mean space closure of 5.2 mm (95% CI 4.8 to 5.6 mm, I-squared=34%) with favorable long-term stability (mean irregularity increase 0.3 mm, 95% CI 0.1 to 0.5 mm, I-squared=28%). Low-certainty evidence indicates clear aligner accuracy is limited to 78.9% of predicted incisor tip movement (3 studies, n=187, 95% CI 72.3 to 85.5%, I-squared=41%); these findings may not reflect newer generation aligner systems. Low-certainty evidence suggests maxillary incisor movement following premolar extraction (6 studies using tomographic imaging, n=387) results in palatal bone resorption (mean -0.43 mm, 95% CI -0.62 to -0.24 mm, I-squared=52%), with greater effects in adults versus adolescents (mean difference 0.31 mm, p = 0.02); although statistically significant, the magnitude may be clinically negligible in patients with adequate baseline alveolar thickness. Moderate-certainty evidence indicates en-masse retraction results in faster space closure than two-step retraction (4 RCTs, n=214, mean -4.2 months, 95% CI -5.8 to -2.6 months). Moderate-certainty evidence shows root resorption incidence is 12.4% (95% CI 8.7 to 16.1%), with subgroup analysis: greater than 2 mm threshold 13.2% (7 studies), at least one-quarter root length threshold 11.4% (5 studies). Low-certainty evidence suggests extraction versus non-extraction comparisons (4 studies, n=326) show no significant differences in relapse. Conclusions: Mandibular incisor extraction demonstrates favorable long-term stability with minimal profile changes but requires recognition of clear aligner accuracy limitations. Maxillary incisor movement carries risks including palatal bone resorption, particularly in adults, though the clinical significance may vary with baseline alveolar thickness. En-masse retraction results in faster space closure with comparable root resorption risk. Treatment decisions should consider patient-specific factors including age, alveolar bone morphology, malocclusion pattern, and appliance selection.

Prosthetic devices balance functionality and usability to support activities of daily living (ADLs). However, many designs rely on rigid end effectors that, while anthropomorphic in form, lack biomimetic design principles. This mismatch increases cognitive and physical burden, reducing adoption rates. We developed the Human-inspired Actuator Modeling and Reconstruction (HAMR) process, a user-centered framework informed by individual morphology and functional needs, to generate customized agonist/antagonist tendon-actuated end effectors. Using HAMR, we created the Tendon Actuated Prosthetic Hand (TAPH), which integrates human-derived geometry with adaptive force distribution to promote natural object interaction. In a study with 12 participants without limb difference, TAPH was compared to a structurally similar tendon-actuated hand with generalized anthropomorphic geometry across three ADL tasks of varying complexity. TAPH significantly improved task performance and reduced physical effort, mental workload, and frustration, particularly during gross motor tasks. For fine motor tasks, performance improved under stable conditions but not during tasks requiring dynamic precision and continuous coordination. These findings highlight the functional benefits of biologically informed prosthesis design and support biomimetic principles in enhancing performance and user experience.

Clavicle fractures often exhibit markedly different clinical outcomes: some patients recover acceptable function despite shortening or displacement, whereas others with apparently similar deformity develop persistent pain, functional loss, or poor healing. To explain this distinction, we propose a minimal nonlinear mechanical model for prognostic analysis of clavicle fractures. The model describes the interaction between fracture-related shortening and compensatory shoulder-girdle posture through a reduced equilibrium equation incorporating stiffness, geometric nonlinearity, and shortening-posture coupling. Within this framework, we analyze equilibrium branches, local stability, and the emergence of critical thresholds. We show that post-fracture destabilization can be interpreted as a fold bifurcation, while more complex parameter dependence gives rise to cusp-type structures and multistability. These bifurcation mechanisms provide a mathematical explanation for sudden deterioration after injury or treatment, as well as for strong inter-individual variability. We further introduce an optimization principle based on a utility functional to guide treatment planning. The analysis predicts that the optimal safe correction should lie strictly below the bifurcation threshold, thereby generating a natural safety margin. Although the model is simplified and has not yet been calibrated against patient data, it nevertheless provides a theoretical framework for understanding why fracture prognosis may deteriorate abruptly near critical mechanical conditions and offers a dynamical-systems interpretation of empirical treatment thresholds used in clinical practice.

ObjectiveTo evaluate the real-world effectiveness of Intact Fish Skin Graft (IFSG) compared with standard of care (SOC) in the treatment of Stage 3-4 pressure ulcers, using clinically meaningful outcomes including wound healing rate and percent area reduction (PAR). Materials and MethodsA retrospective matched cohort study was conducted using deidentified electronic health record (EHR) data from the U.S. Wound Registry. Patients with Stage 3-4 pressure ulcers treated with IFSG (n=40) were compared to a matched SOC control group (n=40). 1:1 covariate matching was performed to reduce confounding across key patient and wound characteristics, including age, mobility status, comorbidities (e.g., diabetes, peripheral artery disease), and wound features (age, size, location, and depth). Outcomes included healed status, healed or improved rate, and percent area reduction (PAR). ResultsThe study population represented a high-risk, real-world cohort (n=40 per group), with only 37.5% ambulatory patients and a high prevalence of multiple concurrent wounds. IFSG treatment demonstrated superior clinical outcomes compared to SOC: O_LIHealed or improved: 67.5% (IFSG) vs 55.0% (SOC) (p=0.0379) C_LIO_LIHealed: 45.5% (IFSG) vs 33.3% (SOC) C_LIO_LIPercent area reduction (PAR): 49% (IFSG) vs 34% (SOC) (p=0.0028) C_LI These findings indicate statistically significant improvements in percent area reduction and in the proportion of wounds that were healed or improved with IFSG. The proportion achieving complete healing was numerically higher with IFSG than with SOC, but this difference did not reach statistical significance. ConclusionIn this real-world matched cohort analysis, Intact Fish Skin Graft demonstrated superior effectiveness compared to standard of care in the management of Stage 3-4 pressure ulcers, with improvements in healing-related outcomes and percent area reduction. These results support the use of IFSG as an effective advanced therapy for hard-to-heal pressure ulcers.

Wearable devices for gravity balancing have high potential for impact across domains, including neuromotor rehabilitation and occupational systems. Devices made from compliant mechanisms, optimized to achieve specific compensation moments at target joints, have proven effective, but thus far have solely been optimized towards gravity compensation and not other wearability criteria. In this work, we propose a multi-objective optimization framework, based on particle swarm optimization, to design a soft, gravity balancing shoulder orthosis, while taking into account wearability constraints such as undesired loading directions and device size. Using this custom framework, we pursued multiple stages of orthosis design and optimization, selecting multiple solutions to be translated to real-world prototypes. These solutions were realized via 3D printing with thermoplastic polyurethane and evaluated for mechanical performance on benchtop and in-vivo. In-vivo testing on 6 healthy individuals demonstrated relative reductions in muscle activity for the anterior deltoid and upper trapezius, by 53 % and 71 % respectively when operating the orthosis for static tasks within functional shoulder ranges of motion. Changes in muscle activation were also were observed across other muscles, including the posterior deltoid, as well as in dynamic tasks at different speeds.

Walking speed is widely used to assess gait recovery following stroke, yet it provides limited insight into how walking performance is mechanically organized. This study examined how center of mass (COM) work organization and propulsion-support coupling vary across walking speeds in individuals with post stroke hemiparesis to distinguish recovery of gait organization from recovery of limb level mechanical function. Eleven individuals with post stroke hemiparesis performed treadmill walking across speeds ranging from 0.2 to 0.7 m/s while ground reaction forces were recorded. Limb specific COM power and work were computed using an individual limbs framework, and interlimb asymmetry in net and positive work, along with the propulsion-support ratio (PSR), were quantified. A qualitative transition in gait organization was observed: at lower walking speeds, COM power exhibited a simplified two phase pattern, whereas at higher walking speeds (approximately >=0.5 m/s), a structured four phase COM power pattern emerged, including identifiable push off and preload phases. Despite this recovery of gait organization, interlimb work asymmetry remained elevated and paretic PSR remained reduced across all speeds, indicating persistent limb level mechanical deficits. These findings demonstrate that increases in walking speed and the emergence of typical COM power structure reflect recovery of gait organization rather than restoration of underlying limb level mechanical capacity. Consequently, walking speed alone is insufficient to characterize gait recovery after stroke, and biomechanically informed measures of COM work organization and propulsion-support coupling provide complementary insight by distinguishing organizational recovery from limb-level mechanical recovery.

Objectives: To determine the impact of discharge home on physical activity and sedentary behaviour following orthopaedic trauma. Design: Observational study. Setting: Acute hospital. Participants: Between October 2022 and January 2024, 31 adult orthopaedic trauma patients were recruited during hospital admission. Participants had either an isolated hip fracture or multi-trauma (i.e., a lower limb fracture, with an upper limb and/or spinal fracture). Interventions: Participants wore two activity monitors (activPAL3 and ActiGraphGT3x) during the final days of an acute hospital admission and the first five days at home. An interrupted time series analysis evaluated changes physical activity variables during the hospital to home transition. Participants were analysed individually using mixed-effects linear regression allowing the intercept to vary by participant. Main outcome measures: Primary outcome was daily steps; secondary outcomes included sedentary time and other activity measures. Results: Daily steps (mean +- SD) were higher at home (4552.4 +- 2639.5) compared to hospital (2597.8 +- 1450.8). Modelled results indicated a 27% increase in daily steps following hospital discharge (exp(beta946;): 1.27, 95% CI: 1.01,1.59, p=0.039) and a sustained improvement at home. No significant differences were observed between hip fracture and multi-trauma participants. Conclusion: Participants recovering from orthopaedic trauma showed a significant increase in daily step count upon discharge home from hospital, highlighting the positive impact of the home environment on activity levels. Further research is warranted to assess the effectiveness of interventions to improve activity levels in hospital (e.g., early intensive therapy) and at home (e.g., immediate home-based physiotherapy) in individuals following orthopaedic trauma.

Head rotation is the leading cause of diffuse brain injuries from cycling accidents, with severe, long-term or even fatal consequences. Here, we present a novel helmet safety technology, the Release Layer System (RLS), designed to enhance conventional helmets and reduce the likelihood of such injuries. RLS is located on the outer side of the helmet and thus gets impacted first. The force of the impact activates a rolling mechanism triggering the release of an outer polycarbonate panel, thereby dispersing and transforming a substantial portion of the incident rotational energy. To evaluate the effectiveness of the technology, we conducted oblique impact tests on three popular helmet types, in conventional and RLS-equipped configurations, at three impact locations. RLS-equipped helmets reduced Peak Angular Velocity (PAV) by 57-66%, averaged across impact locations, compared to their conventional counterparts. This corresponds to a 68-86% reduction in the probability of an AIS2+ brain injury, as estimated by the Brain Injury Criterion. The most notable improvement was observed at the pYrot location (front impacts, mid-sagittal plane), with up to 85% PAV reduction. Testing across headforms further demonstrated the effectiveness of the technology in mitigating head rotation irrespective of variations in evaluation setups. This work introduces a novel mechanism for rotational impact mitigation and provides evidence of its potential benefits compared with conventional helmets. As an outer-layer approach, RLS may offer an alternative pathway for managing rotational kinematics in future helmet designs.

Background/Objective: The Network Pain Rehabilitation Limburg (NPRL) was established to provide integrated, biopsychosocial-based rehabilitation care for patients with chronic musculoskeletal pain, emphasizing the delivery of appropriate care by the right person at the right place and cost. This study examines the perceived interprofessional collaboration practice (ICP) and work satisfaction among primary care healthcare professionals engaged in NPRL. Patients and Methods: A mixed-methods approach involved seven general practitioners (GPs), twenty-four therapists (physiotherapists and occupational therapists), and five mental health practice nurses in eleven semi-structured focus groups and one interview conducted from 2017 to 2020. The Interprofessional Collaboration Attainment Survey quantitatively measured healthcare professionals' ICP abilities before and after NPRL participation. Qualitative analysis, structured around existing ICP frameworks and the Quadruple Aim, was based on interview data. Results: Findings revealed stable ICP and work satisfaction, with discussions focusing on transitioning to a biopsychosocial perspective on chronic pain and its implications, along with concerns about GP burden and insurer reimbursement issues. Significant enhancements were noted in communication and team functioning (p < 0.05). Conclusions: Overall, healthcare professionals reported positive experiences with NPRL's integrated approach, showcasing dedication to providing rehabilitation care for chronic musculoskeletal pain in primary care. Recommendations for improving ICP included advocating for a broader societal biopsychosocial view of chronic pain, introducing case managers in primary care to support GPs, and exploring alternative reimbursement models with insurers. However, significant transformations to impact work satisfaction and ICP may necessitate more time and consideration.

The thymus plays a pivotal role in the generation of immunocompetent T cells. Although its function is dependent on its complex extracellular matrix, its 3D architecture and mechanical properties remain poorly characterised This knowledge gap limits efforts to model and engineer the organ, which is a critical step towards the development of strategies for the treatment of many haematological and autoimmune diseases. Here, we provide the first comprehensive multiscale dataset of bovine thymic extracellular matrix architecture and viscoelastic behaviour, including quantitiative descriptors such as relaxation times, instantaneous and equilibrium elastic moduli, storage and loss moduli, and spatial mechanical heterogeneity. Taken together, our data define the thymus as a compliant, highly dissipative viscoelastic organ with a fibrillar architecture. They also represent a unique database, which, for the first time, paves the way for quantitative thymus tissue engineering.

Dermal bone, which forms a variety of skeletal structures and persists in a wide range of extant vertebrates, evolved prior to endochondral bone which forms all mammalian load-bearing bones. Sturgeons are a family of fish which diverged soon after the lobe-finned/ray-finned split. Sturgeon retain a long robust spine at the leading edge of the pectoral fin, called the pectoral fin spine (PFS). Pectoral fin spines are bone elements that are present in many extinct and extant species of non-tetrapod jawed fish. In this study, we characterize the structure (light, polarized, micro-computed tomography and scanning electron microscopy), composition (FTIR, TGA, BMD), and mechanical properties (3-point bending and microindentation) of the pectoral fin spine (PFS) of the Russian sturgeon (Huso gueldenstaedtii). The microstructure of the PFS is highly organized as it is formed by dermal osteonal bone and parallel fibered bone. Its microarchitecture, along with high material toughness, anisotropy, and substantial ash content, enables the PFS to bear loads and function in both locomotion and protection. In addition, we show an interconnected network of neurovascular canals and ornamentations, features also found in pectoral fin spines of other non-tetrapod jawed fish. Collectively, these findings demonstrate that dermal bone can form structurally organized, mechanically competent load-bearing elements and provide new insight into pectoral fin spines in ray-finned fish.

BACKGROUND: Cranioplasty is an essential procedure to restore cranial integrity, protect neural structures, and improve cosmetic outcomes. However, commercially available implants are often costly, limiting their accessibility in public healthcare systems. Three dimensional (3D) printing offers a low cost alternative for producing patient-specific solutions. METHODS: A retrospective case series of eight patients undergoing cranioplasty using customized polymethylmethacrylate (PMMA) implants fabricated with 3D printed molds was conducted. Computed tomography (CT) scans were used for segmentation and digital modeling. Patient specific molds were designed and printed preoperatively. Variables analyzed included design time, printing time, intraoperative workflow, and clinical outcomes. RESULTS: Design time ranged from approximately 1 hour for small defects to 3 hours for larger defects. Printing time ranged from 2 3 hours for smaller defects and up to 8 10 hours for larger reconstructions. Satisfactory aesthetic outcomes were achieved in 7 of 8 patients (87.5%). No major implant related complications were observed. CONCLUSION: Low cost 3D printing for PMMA cranioplasty is a feasible, accessible, and effective technique for cranial reconstruction, particularly in resource limited settings. Keywords: Cranioplasty; 3D printing; Cranial defect reconstruction; Low cost surgery; Patient specific implants; Polymethylmethacrylate; Skull reconstruction