Training Patterns Research Articles

Experimental analysis on post-fire performance of GRAC filled steel tubular columns and thermal properties of GRAC

This paper presents experimental investigation on the post-fire performance of geopolymeric recycled aggregate concrete filled steel tube (GRACFST) columns and temperature field of GRAC cubes. A total of 10 GRACFST column specimens were tested to investigate their post-fire performance. A total of 10 GRACFST column specimens were tested to evaluate their performance after exposure to fire, considering various parameters: (a) cross-section type (circular and square); (b) testing conditions (ambient temperature test, post-fire test without initial load, and full-coupled post-fire test); (c) target temperatures (20 ℃, 600 ℃, and 800 ℃); and high-temperature exposure durations (30 min and 180 min). The study examined failure modes, temperature evolution, deformation and strain patterns, and post-fire ultimate bearing capacities. The test data revealed the commendable post-fire performance of GRACFST columns, as evidenced by the residual strength index typically falling within the range of 0.83 to 1.11. To calibrate the thermal properties of GRAC materials, a series of temperature field tests of GRAC cubes at different target temperatures (200 ℃, 400 ℃, 600 ℃ and 800 ℃) were conducted. These tests provided data on temperature distribution within the cubes and mass loss due to high temperatures. Using back analysis of these temperature field tests, thermal property models for GRAC, including thermal conductivity, specific heat, and density, were developed and validated by simulating temperature data from existing fire and post-fire tests of GRACFST columns. The proposed thermal property models are crucial for designing this novel composite column type for fire resistance applications.

Experimental and Numerical Simulation on the Generation and Development of Cumulative Plastic Strain of Cement Sheath in Salt Cavern Gas Storage Well

ABSTRACTSalt cavern gas storage is an important technical means to balance the demand for staggered energy supply. Due to the repeated injection and extraction of natural gas in gas storage facilities, sealing integrity failure in the wellbore of gas storage facilities frequently occurs. In response to this, considering the cyclic loading and unloading of the pressure load inside the casing, mechanical tests of set cement were carried out under alternating loads, quantifying the cumulative plastic strain change law of set cement and revealing the deterioration characteristics of its mechanical properties. A numerical model of cumulative plastic strain of casing cement sheath formation under alternating load was established based on the obtained experimental parameters. Comparative verification was conducted using experimental data, and the variation law of cumulative plastic strain of cement sheath was analyzed. The distribution of cumulative plastic strain on the cement sheath bonding surface of the entire wellbore was quantified. The research results indicate that the higher the internal pressure value of the casing, the earlier the plastic strain appears, and with the increase in the number of alternating loads, the cumulative plastic strain increases approximately linearly. After the internal pressure increased by 30 MPa, the cumulative plastic strain increased by a maximum of 46.75%. When the number of loading and unloading cycles under alternating loads is small, reducing the elastic modulus (6 GPa) of the cement sheath can effectively reduce its cumulative plastic strain. However, as the number of loading and unloading cycles under alternating loads exceeds a specific value, the cumulative plastic strain produced by high elastic modulus (15 GPa) cement sheaths decreases. Finally, the distribution pattern of cumulative plastic strain along the wellbore under different gas injection times and complex formation conditions was analyzed. Suggestions for establishing well barriers in salt cavern gas storage during cementing were proposed. The research results can provide theoretical and engineering references for evaluating the sealing integrity of gas storage wells.

Experimental research on fatigue behavior of concrete under acid rain corrosive environment

Concrete infrastructures such as high-speed railway bridges, road pavements, and airport runways in acid rain areas are severely affected by fatigue loading and environmental corrosion. To investigate the impact of acid rain corrosion on the fatigue resistance of concrete, 12 groups of concrete specimens were exposed to acid rain spray tests and then subjected to bending fatigue testing. These tests comparatively examined the impact of different stress levels and corrosion ages on the concrete's fatigue life, strain, and damage pattern. Additionally, the fatigue life reliability of the concrete was analyzed using the Weibull distribution theory and equations were developed to predict the fatigue life of the concrete under different probabilities of failure. The results indicate that both stress level and acid rain corrosion age significantly affect the ultimate strain and fatigue life of concrete. High stress levels combined with prolonged acid rain exposure severely degrade the fatigue performance of the concrete. The fatigue life of the concrete follows a Weibull distribution, and the P-S-N curves and fatigue life equations developed based on data from various failure probabilities show a high linear association with values larger than 0.9. These findings can serve as a reference for predicting the fatigue life of concrete in areas affected by acid rain.

Sex Differences in Youth and Young Adult Sport Training Patterns, Specialization, and Return to Sport Durations.

Young female athletes may have higher rates of overuse injuries and sport specialization than male athletes. The association of sports specialization and return to sport (RTS) timeframe is also unknown. Specialized female athletes will have more intense, year-round training patterns, more overuse injuries, and longer RTS times than male athletes. Cohort study. Level 3. Injured athletes aged 10 to 23 years presenting to a sports medicine clinic reported their degree of sport specialization and training patterns. Skeletal maturity was estimated using the Khamis-Roche method. Injury type and RTS timeframes were categorized from electronic medical records. Chi-square tests and logistic regression analysis assessed associations between variables. A total of 485 athletes (40.2% female) were enrolled. Higher degrees of sport specialization were associated strongly with overuse injuries (P < 0.01). After adjusting for specialization, female athletes were more likely to sustain an overuse injury (adjusted odds ratio, 1.49; P = 0.04). Female athletes participated in fewer total physical activity hours per week (P < 0.01), fewer free play hours per week (P < 0.01), and participated in their main sport for more months of the year than their male counterparts (P = 0.02). Female athletes were more likely to be at a higher developmental stage than male athletes (P < 0.01). RTS timeframes were increased in athletes with serious overuse injury; however, no association was found between degree of specialization and RTS time regardless of sex. Female athletes are more likely to sustain overuse injuries with more organized, year-round, training and less free play compared with their male counterparts. Female sex may be an independent risk factor of overuse injury. Future strategies to mitigate these risks may include increased free play hours and limiting year-round training through seasonal rest.

Mechanistic exploration of odorant binding protein-mediated chlorpyrifos resistance in Nilaparvata lugens: Insights from insecticide sequestration and transcriptional regulation

The effectiveness and sustainable application of insecticides are severely threatened by the rapid evolution of resistance in agricultural pests. Recent research indicates that odorant binding proteins (OBPs) may be involved in facilitating insecticide resistance, while the specific mechanisms remain poorly understood. Herein, 11 OBPs were identified from Nilaparvata lugens. Among them, OBP5 exhibited high and specific expression in the head, and showed constitutive overexpression in the chlorpyrifos-resistant strain. Knockdown of OBP5 notably restored susceptibility to chlorpyrifos in N. lugens, while overexpression of OBP5 in Escherichia coli significantly enhanced bacterial tolerance to chlorpyrifos. Fluorescence competitive binding assay confirmed the strong binding affinities of OBP5 to chlorpyrifos and its active metabolite chlorpyrifos-oxon. Molecular docking studies proposed a critical interacting amino acid (Lys147) in the binding site, which was further validated by comparative binding studies between wildtype OBP5 and the mutated protein OBP5K147A. Furthermore, Lim1β that also presented overexpression pattern in the resistant strain, was found to regulate expression of OBP5 through a dual-luciferase reporter assay. Our findings demonstrate that the overexpression of OBP5 contributes to chlorpyrifos resistance by binding and sequestering the insecticides, shedding light on the sequestration resistance mechanism conferred by OBPs and offering potential targets for resistance management.

Single-Scene SAR Image Data Augmentation Based on SBR and GAN for Target Recognition

High-performance neural networks for synthetic aperture radar (SAR) automatic target recognition (ATR) often encounter the challenge of data scarcity. The lack of sufficient labeled SAR image datasets leads to the consideration of using simulated data to supplement the dataset. On the one hand, electromagnetic computation simulations provide high amplitude accuracy but are inefficient for large-scale datasets due to their complex computations and physical models. On the other hand, ray tracing simulations offer high geometric accuracy and computational efficiency but struggle with low amplitude correctness, hindering accurate numerical feature extraction. Furthermore, the emergence of generative adversarial networks (GANs) provides a way to generate simulated datasets, trying to balance computational efficiency with image quality. Nevertheless, the simulated SAR images generated based on random noise lack constraints, and it is also difficult to generate images that exceed the parameter conditions of the real image’s training set. Hence, it is essential to integrate physics-based simulation techniques into GANs to enhance the generalization ability of the imaging parameters. In this paper, we present the SingleScene-SAR Simulator, an efficient framework for SAR image simulation that operates under limited real SAR data. This simulator integrates rasterized shooting and bouncing rays (SBR) with cycle GAN, effectively achieving both amplitude correctness and geometric accuracy. The simulated images are appropriate for augmenting datasets in target recognition networks. Firstly, the SingleScene-SAR Simulator employs a rasterized SBR algorithm to generate radar cross section (RCS) images of target models. Secondly, a specific training pattern for cycle GAN is established to translate noisy RCS images into simulated SAR images that closely resemble real ones. Finally, these simulated images are utilized for data augmentation. Experimental results based on the constructed dataset show that with only one scene SAR image containing 30 target chips, the SingleScene-SAR Simulator can efficiently produce simulated SAR images that exhibit high similarity in both spatial and statistical distributions compared with real images. By employing simulated SAR images for data augmentation, the accuracy of target recognition networks can be consistently and significantly enhanced.

Implementation of the Merdeka Curriculum at Madrasah Tsanawiyah in Aceh Tamiang, Indonesia

This study examines the planning, implementation, and evaluation processes of the Merdeka curriculum, with a particular focus on the integration of Arabic language teaching at Madrasah Tsanawiyah in Aceh Tamiang, Indonesia. This study utilized a qualitative multi-case approach, focusing on three public madrasah's and one private madrasah. Data were collected through observations, interviews, and document analysis, with respondents comprising 20 seventh-grade Arabic and general subject teachers, four madrasah principals, four curriculum deputies, and four madrasah operators. Findings reveal that the Merdeka curriculum planning, implementation, and evaluation at Madrasah Tsanawiyah in Aceh Tamiang varied across institutions. While some schools demonstrated systematic approaches, disparities emerged in teacher training patterns, readiness for 21st-century skills, and the availability of digital education facilities. These challenges hindered the effective implementation of the curriculum and resulted in the absence of a clear evaluation framework. This study recommends that the government and education policymakers enhance teacher training distribution, improve digital education infrastructure, increase teacher welfare, and establish structured evaluation frameworks to optimize curriculum implementation in addressing global challenges.

Strain As An Indicator For Stress Fractures In Racehorses

Abstract The horse racing industry, despite its financial significance, grapples with significant welfare issues, particularly stress fractures in racehorses. Third metacarpal (MC3) bone fractures, constituting about one-third of all limb fractures, severely impact horse health and performance. The frequent occurrence of condylar fractures in the MC3, often resulting in bone comminution, poses high risks-sometimes necessitating euthanasia, and complicates the management and recovery processes for the rest. Comprehensive methods for quantitatively determining fracture risks in horses are lacking, with strain measurements on the MC3 during racing conditions showing promise as an indicator of high loads and potential fracture risks. This study investigated the mechanical properties of MC3 under high compressive loads. Six MC3 bones from euthanized horses were instrumented with strain gauge rosettes at four key locations: Lateral Condyle (CondL), Medial Condyle (CondM), Dorsal DistoLateral (DisL) and Dorsal DistoMedial (DisM). Each bone underwent a pre-loading phase and five cycles of 12kN sinusoidal loading to replicate galloping forces. Strain patterns were observed before and after introducing an artificial slot in the lateral condylar groove to simulate a fatigue crack. A strong correlation was found between load and minimum principal strain in both intact and fatigue crack-induced (FCI) bones, with R-squared values over 0.99. Post-FCI, 83% of bones exhibited an increase in the minimum principal strain-load response slope, indicating uniform changes in material behavior. Additionally, a rise in post-FCI y-intercept values across MC3 locations indicated higher initial strain and possible changes in bone properties.

Electrocardiographic strain and relationship with LV remodelling and clinical outcomes in patients with aortic stenosis undergoing transcatheter aortic valve implantation.

Left ventricular (LV) remodelling and fibrosis is known to occur in patients with aortic stenosis (AS) and is linked to post-intervention outcomes. These myocardial changes may be detected upon the routine 12-lead electrocardiogram by the presence of a LV strain pattern (LVS-ECG). Although LVS-ECG has been related to excessive cardiovascular morbidity and mortality in multiple patient populations, there is currently a dearth of data upon its impact in patients undergoing transcatheter aortic valve implantation (TAVI). The aim of the current study was to investigate the prevalence, predictors and prognostic value of LVS-ECG. Between 2012 and 2019, 640 consecutive patients underwent TAVI at Haukeland University Hospital, Bergen. Of these, 600 patients with severe AS were included in the TAVI-NOR study. Patients with known bundle branch block (n=85) or permanent pacing (n=25) were excluded, leaving 490 patients (mean age 81±6years, 52% females) eligible for the analyses. LVS-ECG was defined as down-sloping, convex ST-segment depression with asymmetric T-wave inversion in V5 or V6. LVS-ECG was present in 25.7% patients. Higher levels of NT-proBNP (OR 1.96; 95% CI:1.08-3.55, p=0.028), LVEF<50% (OR 3.14; 95% CI:1.61-6.13, p=0.001), increase in LV mass index per SD (32g/m2) (OR 1.37; 95 CI:1.06-1.76, p=0.014), and the presence of LV hypertrophy on ECG (OR 3.23; 95% CI:1.97-5.32, p<0.001) were independent predictors of LVS-ECG in the multivariable-adjusted analysis. Although all-cause mortality was significantly higher in patients with LVS-ECG compared to those without (54.8% vs 44.2%, p=0.041), the presence of LVS-ECG did not predict all-cause mortality during a median follow-up of 64±24 months (HR 1.05; 95% CI:0.79-1.39, p=0.742). Patients with LVEF <50% and concomitant LVS-ECG had a worse prognosis than those with LVEF >50% and no LVS-ECG (p<0.001). LVS-ECG may represent a simple marker of structural and functional LV remodelling that signals a propensity to excess mortality during long-term follow-up after TAVI, as it is strongly associated with other prognosticators such as reduced LVEF and increased levels of NT-proBNP.

Empowering primary care physicians in child and adolescent psychiatry: a needs assessment on collaborative care in Dubai.

Child and adolescent psychiatric disorders pose significant public health concerns necessitating prompt intervention. Primary care physicians (PCPs) play a critical role as initial points of contact, facilitating early detection, management, and referral of these conditions. In Dubai, integrating mental health services into primary care faces unique challenges, highlighting the need for systemic reforms and enhanced PCP training. This study investigated perceptions, barriers, and systemic challenges encountered by PCPs in managing child and adolescent psychiatric conditions in Dubai's primary care setting. It also assessed family physicians' involvement and preparedness in this domain. Using a mixed-methods approach, we conducted a survey among family physicians in Dubai Health facilities and analyzed patient data from family medicine clinics. The survey evaluated formal training, preparedness, encounter frequency, and referral patterns for psychiatric care in young patients. Qualitative insights from open-ended survey questions provided additional understanding of specific challenges. Findings revealed significant gaps in formal training, with only 33.3% of respondents trained in child and adolescent psychiatry during medical education, and 21.1% participating in Continuing Medical Education (CME). A majority (54.4%) of PCPs felt unprepared to manage psychiatric care in young patients. Patient data analysis showed a predominance of male patients (59.9%) and identified Autism Spectrum Disorder (43.1%) as the most common condition, emphasizing the reliance on specialized care through a high referral rate (63.1%). Major barriers included time constraints, limited psychiatric knowledge, resistance to mental health services, systemic and structural issues, communication challenges, and resource shortages. Enhanced training and systemic reforms are urgently needed to integrate mental health services effectively into Dubai's primary care. Implementing structured collaborative care models, fostering interdisciplinary collaboration, and addressing systemic barriers are crucial for improving child and adolescent psychiatric condition management. These initiatives promise better patient outcomes and more efficient healthcare resource utilization.

Ultrahigh-Density Polar Vortex Lattice in Square-Shaped Moiré Bilayers of Lead Chalcogenides.

Nanoscale exotic polar topological structures, such as vortices and skyrmions, hold promise for next-generation electronic devices, yet their spontaneous formation in 2D van der Waals (vdW) materials remains quite challenging. Herein, we demonstrate from first-principles that ultrahigh-density polar vortices emerge in the square moiré bilayer formed by twisting two layers of centrosymmetric PbS with the D4h point group. The emerged ferroelectricity arises from the inherent complex strain associated with the twisted structures, and the resulting electron polarization is much greater than that obtained in sliding ferroelectricity. Notably, the engineered strain patterns are characterized by peculiar inhomogeneous in-plane fields with a checkerboard distribution of uniaxial tension. This nanoscale nonuniform strain produces an ultrahigh-density vortex polarization lattice. The results from our study not only reveals a new mechanism for electric polarization and polar topologies in moiré bilayers but also provides opportunities for designing 2D ultrahigh-density electric devices.

Training in the Use of Myoelectric Prostheses Through the Combined Application of Immersive Virtual Reality, Cross-education, and Mirror Therapy

ABSTRACT Introduction During the rehabilitation process (RHB) of the patient with traumatic upper-limb amputation, the use of immersive virtual reality (IVR) facilitates the incorporation of the prosthesis into the body schema. This reinforces and enhances sensorimotor and cognitive stimulation to improve motor learning and motor patterns, while normalizing global gestures. Objectives The aims of this study were to implement retraining of gestural acquisition and prosthetic control in patients with upper-limb injuries and amputations through IVR, and to then incorporate this in the normalization of functional patterns in activities of daily living (ADLs) with the work of “cross-education” as well as the therapy of observation of actions—mirror therapy to enhance the joint effect of the approach with IVR. Methods Standard sessions were established for transradial and transhumeral trauma patients with upper-limb amputation and traumatic injuries within the rehabilitation treatment. During the sessions, games and virtual environment were used. The software ran in desktop mode using a “Leap Motion” or for immersive versions of 3D glasses (Oculus Rift S). Results The application of IVR in combination with conventional treatment obtained significant benefits for functionality. These included learning correct motor execution as well as motivational and emotional state with distal traumatic injuries and upper-limb amputations with or without myoelectric prosthesis, obtaining 5.6 on average on the GROC (global rating of change) scale. Conclusions Immersive virtual reality shows benefit for the normalization of motor learning of functional patterns in DLA and on the emotional, motivational level of the patient. Clinical Relevance The integrated combination of cross-education, mirror therapy, and immersive virtual reality may represent greater acquisition of motor patterns in the prosthetic training of patients with upper-limb amputation.

Numerical modeling and analysis of neck injury induced by parachute opening shock.

Neck injuries from parachute opening shock (POS) are a concern in skydiving and military operations. This study employs finite element modeling to simulate POS scenarios and assess cervical spine injury risks. Validated against various conditions, including whiplash, the model replicates head/neck kinematics and soft tissue responses. POS simulations capture body/head motions during parachute deployment, indicating minimal risk of severe neck injuries (Abbreviated Injury Score/AIS ≥ 2) and low risk of soft tissue tears. Vertebral stress analysis during a rougher jump highlights high stress at C5/C6 lamina, indicating fracture risk. Comparative analysis with rear impact scenarios reveals distinct strain patterns, with rear impacts showing higher ligament strain, consistent with higher soft tissue damage risk. Though POS simulations exhibit lower strain values, they emphasize similar neck deformation patterns. The model's capability to accurately simulate head and neck movements during parachute openings provides critical validation for its use in assessing injury risks. The study's findings underline the importance of considering specific loading conditions in injury assessments and contribute to refining safety standards for skydiving and military operations. By highlighting the differences in injury mechanisms between POS and rear impacts, this research offers valuable insights into tailored injury mitigation strategies. The results not only enhance our understanding of neck injury mechanisms but also inform the development of protective gear and safety protocols, ultimately aiding in injury prevention for skydivers and military personnel.

A study on sleep posture analysis using fibre bragg grating arrays based mattress

Prolonged sleeping postures or unusual postures can lead to the development of various ailments such as subacromial impingement syndrome, sleep paralysis in the elderly, nocturnal gastroesophageal reflux, sore development, etc Fibre Bragg Gratings (a variety of optical sensors) have gained huge popularity due to their small size, higher sensitivity and responsivity, and encapsulation flexibilities. However, in the present study, FBG Arrays (two FBGs with 10 mm space between them) are employed as they are advantageous in terms of data collection, mitigating sensor location effects, and multiplexing features. In this work, Liquid silicone encapsulated FBG arrays are placed in the head (E), shoulder (C, D), and lower half body (A, B) region for analyzing the strain patterns generated by different sleeping postures namely, Supine (P1), Left Fetus (P2), Right Fetus (P3), and Over stomach (P4). These strain patterns were analyzed in two ways, combined (averaging the data from each FBG of the array) and Individual (data from each FBG was analyzed separately). Both analyses suggested that the FBGs in the arrays responded swiftly to the strain changes that occurred due to changes in sleeping postures. 3D histograms were utilized to track the strain changes and analyze different sleeping postures. A discussion regarding closely related postures and long hour monitoring has also been included. Arrays in the lower half (A, B) and shoulder (C, D) regions proved to be pivotal in discriminating body postures. The average standard deviation of strain for the different arrays was in the range of 0.1 to 0.19 suggesting the reliable and appreciable strain-handling capabilities of the Liquid silicone encapsulated arrays.

A portable wireless spirometer device for long-term pulmonary function monitoring and training

Portable wireless respiration sensing devices provide a promising solution to the limitations of traditional spirometers, offering practical options for daily use and long-term monitoring. In this study, we introduce a compact and lightweight respiration sensing device (4.2 × 4.6 × 8.3 cm3, ∼78 g) that delivers real-time wireless feedback, enabling users to assess their pulmonary functions and adjust their breathing patterns for effective breathing training. The parameters of the airflow sensor were determined through theoretical deformation calculations, ensuring a sensing range that covers all potential human respiratory values. Additionally, an optimized airway design significantly improves the device’s sensitivity, achieving approximately a 10.4-fold increase in airflow acceleration at the sensor position. This portable device features a cross-platform interactive graphical interface, making it suitable for various applications, such as convenient expiratory tests, daily exercise assessments, and breathing training. Experimental results demonstrate the device’s capability to accurately distinguish the expiratory characteristics of six volunteers and effectively track respiratory recovery following high-intensity exercise. Furthermore, the device integrates seamlessly into engaging games designed to promote consistent breathing training.

Structural disorder facilitates future memory decisions.

It is well known that perception and cognition are systematically biased towards the recent past. That is, a decision about the current state of a perceptual feature (e.g. orientation) can be predicted based on a recent state of the same feature. Such serial dependencies have been demonstrated across perception, memory and cognition, and have been jointly attributed to an adaptive mechanism meant to promote stability in a constantly changing environment. Here, we argue that this adaptive mechanism prioritizes past information on the most basic structural level, such that the strength of the attractive bias is modulated by the amount of structural coherence in stimuli. We presented visual patterns of varied structural disorder (randomness) prior to a recognition memory decision that required discriminating between trained and novel visual patterns. Both highly generic geometrical shapes and completely random patterns failed to elicit an effect on decisional response times. By contrast, we found recognition memory decisions to be significantly faster in trials where the irrelevant probe pattern was 'optimally' random. This result suggests that decision-making is influenced by the past's informational worth. More importantly, it suggests an optimal amount of uncertainty to facilitate future decisions.

Transcriptional evidence of HPA axis dysregulation in adolescent females: Unique contributions of chronic early-life stressor exposure and maternal depression history

BackgroundDepression risk increases dramatically for adolescent females following the pubertal transition. Although chronic early-life stressor exposure and a maternal history of depression are established risk factors for depression onset in this population, we know little about the biological mechanisms underlying these associations. MethodTo investigate, we examined how chronic early-life stressor exposure and maternal depression history were associated with stress-related gene expression patterns, using a high-risk family design in 48 psychiatrically healthy adolescent females, 20 of whom had a mother with a lifetime history of depression. Lifetime chronic stressor exposure was assessed using the STRAIN and gene expression patterns were estimated using transcriptional profiling of whole blood. ResultsConsistent with hypotheses, we found that adolescent females with greater chronic stressor exposure had higher NR3C1 expression levels compared to those with less chronic stressor exposure. Additionally, youth with a depressed mother had lower levels of FKBP5 expression compared to those without a depressed mother. Levels of FKBP5 expression, in turn, interacted with chronic stressor exposure to predict NR3C1 expression. Specifically, for those with low chronic stressor exposure, levels of FKBP5 and NR3C1 expression were strongly interrelated, whereas for those with high chronic stressor exposure, NR3C1 expression was high regardless of levels of FKBP5 expression. LimitationsThis study was correlational, the sample size was limited, and additional research is needed to elucidate the underlying mechanisms and predict who subsequently develops depression. ConclusionsNotwithstanding these limitations, these data indicate that having low FKBP5 expression, alongside high NR3C1 expression, may be a potential preclinical marker of depression risk in adolescent females that warrants additional investigation.

ISTA Award 2023: Toward functional reconstruction of the pre-diseased state in total knee arthroplasty.

The surgical target for optimal implant positioning in robotic-assisted total knee arthroplasty remains the subject of ongoing discussion. One of the proposed targets is to recreate the knee's functional behaviour as per its pre-diseased state. The aim of this study was to optimize implant positioning, starting from mechanical alignment (MA), toward restoring the pre-diseased status, including ligament strain and kinematic patterns, in a patient population. We used an active appearance model-based approach to segment the preoperative CT of 21 osteoarthritic patients, which identified the osteophyte-free surfaces and estimated cartilage from the segmented bones; these geometries were used to construct patient-specific musculoskeletal models of the pre-diseased knee. Subsequently, implantations were simulated using the MA method, and a previously developed optimization technique was employed to find the optimal implant position that minimized the root mean square deviation between pre-diseased and postoperative ligament strains and kinematics. There were evident biomechanical differences between the simulated patient models, but also trends that appeared reproducible at the population level. Optimizing the implant position significantly reduced the maximum observed strain root mean square deviations within the cohort from 36.5% to below 5.3% for all but the anterolateral ligament; and concomitantly reduced the kinematic deviations from 3.8 mm (SD 1.7) and 4.7° (SD 1.9°) with MA to 2.7 mm (SD 1.4) and 3.7° (SD 1.9°) relative to the pre-diseased state. To achieve this, the femoral component consistently required translational adjustments in the anterior, lateral, and proximal directions, while the tibial component required a more posterior slope and varus rotation in most cases. These findings confirm that MA-induced biomechanical alterations relative to the pre-diseased state can be reduced by optimizing the implant position, and may have implications to further advance pre-planning in robotic-assisted surgery in order to restore pre-diseased knee function.

Overlapping Strain Patterns in Patients With Cardiac Amyloidosis and End‐Stage Renal Disease

Overlapping Strain Patterns in Patients With Cardiac Amyloidosis and End‐Stage Renal Disease

A Customized Distribution of the Coefficient of Friction of the Porous Coating in the Short Femoral Stem Reduces Stress Shielding

Stress shielding and aseptic loosening have been identified as adverse effects of short-stem total hip arthroplasty resulting in hardware failure. However, there is a gap in research regarding the impact of stress shielding in customized porous coatings. The purpose of this study was to optimize the distribution of the coefficients of friction in the porous coating of a metaphyseal femoral stem to minimize stress shielding. Static structural analysis of an implanted short, tapered-wedge stem with a titanium porous coating was performed with the use of Analysis System Mechanical Software under axial loading. To limit computational time, we randomly sampled only 500 of the possible combinations of coefficients of friction. Results indicate that the coefficient of friction in the distal lateral porous coating significantly affected the mid-distal medial femoral surface and lateral femoral surface. The resultant increased proximal strains resulted from an increased coefficient of friction in lateral porous coating and a reduction in the coefficient of friction in medial mid-distal coating. These findings suggest that a customized porous coating distribution may produce strain patterns that are biomechanically closer to intact bone, thereby reducing stress shielding in short femoral stems.