Risk Of Instability Research Articles

Neuromuscular Control in Incline and Decline Treadmill Running: Insights into Movement Synergies for Training and Rehabilitation

Treadmill running simulates various conditions, including flat, uphill, and downhill gradients, making it useful for training and rehabilitation. This study aimed to examine how incline and decline treadmill running affect local dynamic stability of individual running movement components that cooperatively contribute to achieving the running tasks. Principal component analysis (PCA) was used to decompose movement components, termed principal movements (PMs), from kinematic marker data collected from 19 healthy recreational runners (9 females and 10 males, 23.6 ± 3.7 years) during treadmill running at 10 km/h across different gradients (−6, −3, 0, +3, +6 degrees). The largest Lyapunov exponent (LyE) of individual PM positions (higher LyE = greater instability) was analyzed using repeated-measures ANOVA to assess treadmill gradient effects across PMs. The results showed that the effects of treadmill gradient appear in PM3, which corresponds to the mid-stance phase of the gait cycle. Specifically, decline treadmill running significantly decreased local dynamic stability (greater LyE) compared to equivalent incline conditions (p ≤ 0.005). These findings suggest that decline treadmill running should be used cautiously in rehabilitation settings due to its potential to reduce an ability to control and respond to small perturbations, thereby increasing the risk of instability during the weight-bearing support phase of gait.

Optimization of In-Motion EV Charging Infrastructure for Power Systems Using Generative Adversarial Network-Based Distributionally Robust Techniques

This paper presents an innovative optimization framework for the co-management of dynamic electric vehicle (EV) charging lanes and power distribution networks, addressing grid stability amidst fluctuating EV charging demands. Integrating generative adversarial networks (GANs) and distributionally robust optimization (DRO), the framework models uncertainties in traffic flow and renewable energy generation, optimizing system performance under worst-case conditions to mitigate risks of grid instability. Applied to a highway with eight dynamic charging lanes (500 kW per lane), serving up to 50 EVs simultaneously, the framework balances energy contributions from 15 renewable generators (60% of the mix) and 10 non-renewable generators. Simulation results highlight its effectiveness, maintaining grid stability with voltage deviations within 0.02 p.u., reducing energy losses to under 0.8 MW during peak traffic (1500 vehicles per hour), and achieving 95% lane utilization. Dynamic charging enabled EV users to save USD 0.08 per kilometer through reduced stationary charging downtime, optimized travel efficiency, and lower energy costs. Additionally, the system minimizes maintenance costs by optimizing lane and grid reliability. This study underscores the potential of GAN-based DRO methodologies to enhance the efficiency of power grids supporting dynamic EV charging, offering scalable solutions for diverse regions and traffic scenarios.

An investigation into the impact of diapir structures on formation pressure systems: a case study of the Yinggehai Basin, China

Under the influence of diapir structure, the formation pressure system is complicated. The characteristics of high temperature and high pressure are obvious, the prediction is difficult, and complex accidents such as well kick and leakage are frequent, which seriously restrict the efficient development of oil and gas resources. Therefore, taking Yinggehai Basin in China as an example, combined with the evolution characteristics of diapir structure, the influence of diapir structure on abnormal high-pressure, wellhole collapse and fracture is analyzed. Three pressure calculation methods are selected, and the distribution rules of pressures and safety density window are analyzed, too. The results show that the diapir structure and its associated fault not only constitute the fluid transport system, but also make the deep overpressure transfer upward and accumulate into high pressure in the shallow formation, and the development of the associated fault destroy the integrity of the formation rock and reduce the strength of the rock. The upwelling of hot fluid changes the local geothermal conditions, reduces the hydrocarbon generation threshold of shallow source rocks, promotes the evolution of clay minerals, causes hydrothermal expansion, and enhances the shallow high pressure. In high-temperature environment, the cooling effect of drilling fluid will produce heating stress, change the stress distribution around the wellhole, and increase the risk of wellbore instability. Additionally, under the influence of diapir structures, the pore pressure in deep formations increases, while the fracture pressure decreases, resulting in a significantly narrowed safe density window. The safety density window width generally presents a half-spindle shape, and with the increase of depth, the window width increases first and then decreases.

Degeneration of the nucleus pulposus affects the internal volumetric strains and failure location of adjacent human metastatic vertebral bodies.

Intervertebral disc (IVD) degeneration is suspected to affect the distribution of stress and strain near the vertebral endplates and in the underlying bone. This scenario is worsened by the presence of metastatic lesions on the vertebrae (primarily thoracic vertebrae (60-80%)) which increase the risk of fracture. As such, this study aimed to evaluate the effect of IVD degeneration on the internal volumetric strains and failure modes of human metastatic vertebral bodies. Five human thoracic spinal segments including one vertebra with lytic metastases and one radiologically healthy vertebra (control) were in-situ tested in pure compression within a mCT scanner (isotropic voxel size = 39 mm). Each specimen was tested in the elastic regime before and after inducing mock IVD degeneration (enzymatic degeneration with collagenase); and at failure after IVD degeneration. The volumetric strain field was measured using a global Digital Volume Correlation approach (BoneDVC). After IVD degeneration, larger maximum (+187%, P = 0.002, 95% CI= [-4447, -1209]) and minimum (+174%, P = 0.002, 95% CI= [1679, 4258]) principal strains were observed in both metastatic and control vertebrae, with peak differences in correspondence of the IVD anulus fibrosus. IVD degeneration caused a transversal fracture pattern in the vertebrae with failure location onset in the middle portion of the vertebral body and in the cortical shell. In conclusion, IVD degeneration was found to be a key factor in determining the failure mode, suggesting the clinical relevance of including IVD level of degeneration to assess patients' risk of spinal instability. STATEMENT OF SIGNIFICANCE: Vertebrae can be affected by pathologies, like bone metastases, while intervertebral discs tend to degenerate during life. Generally, these structures and pathologies are studied separately. In this study, we explored the effects of artificial intervertebral disc degeneration on the mineralised tissues of the vertebrae with metastases. We observed that the induced intervertebral disc degeneration changes the mechanical behaviour of the vertebral trabecular bone. We believe that the findings of this study may influence the scientific community to develop new clinical tools for the prediction of the risk of fracture in vertebrae with spinal metastases, including the degeneration of the intervertebral discs as a parameter.

Vision-based postural balance assessment of sit-to-stand transitions performed by younger and older adults.

The use of inertial measurement units (IMUs) in assessing fall risk is often limited by subject discomfort and challenges in data interpretation. Additionally, there is a scarcity of research on attitude estimation features. To address these issues, we explored novel features and representation methods in the context of sit-to-stand transitions. This study recorded sit-to-stand transition test data from three groups: community-dwelling elderly, elderly in day care centers (DCC), and college students, captured using mobile phone cameras. We employed pose estimation technology to extract key point kinematic features from the video data and used 10-fold cross-validation to train a random forest classifier, mitigating the impact of individual differences. We trained classifiers with the top 5, 10, and 15 features, calculating the average area under the receiver operating characteristic curve (AUC) for each model to compare feature importance. Our results indicated that elbow key point features, such as (KP08) mean Y, (KP08)RMS Y, (KP09) mean Y, and (KP09) RMS Y, are crucial for distinguishing between subject groups. Statistical tests further validated the significance of these features. The application of human pose estimation and key point signals shows promise for clinical postural balance screening. The identified features can be utilized to develop non-invasive tools for assessing postural instability risk, contributing to fall prevention efforts. This study lays the groundwork for integrating additional measurement modalities into sit-to-stand transition analysis to enhance clinical strategies.

Osteoid osteoma and osteoblastoma of the cervical spine in the pediatric population: analysis of the literature and experience with four operated cases.

Osteoid osteoma (Oo) and osteoblastoma (Ob) are rare primary bone tumors with a higher prevalence in the second decade of life. Treatment can be conservative, but in cases of spinal location, resective surgery is of great importance but may be challenging. We report four pediatric cases of Oo and Ob managed in our unit, with different locations at the level of the cervical spine. All four patients had a common complaint of persistent and progressive neck pain, two reported worsening pain at night, and three underwent NSAID treatment attempts without significant response. The radiological examination revealed a lesion of bone origin in the cervical spine in all cases: two at the pediculolaminar complex, one at the laminar, and one at the level of the C2 body and odontoid. A comprehensive literature review was carried out by comparing the data and a discussion of the cases. A complete surgical resection was performed by a posterior approach in three patients and a transoral in one. A hard neck collar under molding ensured postoperative stability in all cases. Control imaging studies demonstrated satisfactory lesion resection. Histologically, three cases were an osteoblastoma and one an osteoid osteoma. Control imaging studies demonstrated satisfactory lesion resection with good late bone reconstruction. Ultimately, none showed late instability requiring fixation. The mean follow-up time is 36 (16-63) months. None had a recurrence nor late instability requiring fixation. Treatment of pediatric cervical spine of osteoid osteoma and osteoblastoma should seek a complete resection. In regions with a risk for secondary instability, the preservation of capsule-ligamental structures and temporary orthopedic immobilization can allow bone regeneration with no need for fixation. Extended follow-up is recommended especially in very young children to avoid late instability.

Laser-Based Length-Measuring Board for the Measurement of Infant Body Length from Outside an Incubator: Proposal and Assessment of a Model.

Opening the incubator side wall to insert a non-sterile length-measuring device carries the risk of microbial contamination and thermal instability for preterm infants. To reduce this inconvenience, a laser-based length-measuring board is proposed to measure body length from outside the incubator. This device has two laser-line-shaped cursors which can be pointed to opposite ends of a segment to be measured. It is attached to the outer side of one of the incubator's side walls in such a manner as to ensure that its axis is parallel to the longitudinal axis of the segment. To validate the measurements made with this model, a calibrated caliper consisting of a conventional rigid length-measuring board with a resolution of 0.05 mm was constructed to serve as a reference. Crown-heel length was measured in a sample of 45 infants, including 32 preterm and 13 term infants of corrected gestational age at the time of measurement. Good intra-observer variability was obtained. Near-perfect statistical agreement was found between measurements with both devices, with concordance correlation coefficients of 0.994 (95% CI: 0.990; 0.996) in preterm infants and 0.994 (95% CI: 0.988, 0.998) in infants at term. The clinical relevance of the agreement between measurements was assessed by a Bland-Altman plot, and the difference may reach clinical relevance (up to 1 cm) but without evidence of proportional bias. The proposed validated laser-based length-measuring board offers a suitable alternative to conventional length-measuring boards for contactless measurement of infant body length.

Total knee arthroplasty in patient with poliomyelitis sequelae: maintaining a recurvatum is associated with better mid-term functional results.

Total knee arthroplasty (TKA) in patients with sequelae of poliomyelitis is a surgical challenge due to muscle weakness, bone deformities or post-polio syndrome (PPS). Few data exist to determine the factors contributing to poor functional results. This study aimed: (1) to describe a cohort of patients with poliomyelitis sequelae who underwent TKA; (2) to examine risk factors for poor functional outcome. A monocentric retrospective cohort study of all patients with poliomyelitis sequelae who underwent TKA between January 2006 and December 2019. Clinical, functional outcomes, radiographic results and occurrence of complications were collected. A total of 22 patients (24 knees) were included in the analysis, with a mean follow-up of 6.6 years (from 2 to 13.7 years). There was an improvement in KSS (28 +/- 23 vs. 81 +/- 6, respectively; p < 0.0001) as well as functional KSS (25 +/- 12 vs. 57.5 +/- 21, respectively; p = 0.0001). There was less occurrence of annual knee giving way episodes after total knee replacement (11.9+/-16.1 vs. 5.1+/-13.7, respectively; p = 0.04). Even though the total knee replacement allowed a slight recurvatum, it was smaller than the preoperative recurvatum (13° vs. 8°, respectively; p = 0.04). Seven complications with reintervention (7/24; 29%) were found. The presence of a residual post operative recurvatum correlated with better KSS (ρ = 0.53, CI95% [0.15; 0.77]; p = 0.008). The number of postoperative annual knee giving way episodes was inversely correlated with persistent postoperative recurvatum (ρ = -0.42, CI95% [-0.69; -0.01]; p = 0.04) but was not correlated with the type of constraint (ρ = -0.26, CI95% [-0.6; 0.15]; p = 0.21) nor with quadricipital muscle strength (ρ = 0.21, CI95% [-0.21; 0.56]; p = 0.33). TKA has a good mid-term functional outcome for knee osteoarthritis in patients with sequelae of poliomyelitis. Preserving a residual recurvatum postoperatively gives better clinical results without increasing the risk of ligament instability or early aseptic loosening. IV.

Immortalization of Mesenchymal Stem Cells for Application in Regenerative Medicine and Their Potential Risks of Tumorigenesis.

Regenerative medicine utilizes stem cells to repair damaged tissues by replacing them with their differentiated cells and activating the body's inherent regenerative abilities. Mesenchymal stem cells (MSCs) are adult stem cells that possess tissue repair and regenerative capabilities and immunomodulatory properties with a much lower risk of tumorigenicity, making them a focus of numerous clinical trials worldwide. MSCs primarily exert their therapeutic effects through paracrine effects via secreted factors, such as cytokines and exosomes. This has led to increasing interest in cell-free therapy, where only the conditioned medium (also called secretome) from MSC cultures is used for regenerative applications. However, MSCs face certain limitations, including cellular senescence, scarcity, donor heterogeneity, complexity, short survival post-implantation, and regulatory and ethics hurdles. To address these challenges, various types of immortalized MSCs (ImMSCs) capable of indefinite expansion have been developed. These cells offer significant promise and essential tools as a reliable source for both cell-based and cell-free therapies with the aim of translating them into practical medicine. However, the process of immortalization, often involving the transduction of immortalizing genes, poses potential risks of genetic instability and resultant malignant transformation. Cell-free therapy is particularly attractive, as it circumvents the risks of tumorigenicity and ethical concerns associated with live cell therapies. Rigorous safety tests, such as monitoring chromosomal abnormalities, are critical to ensure safety. Technologies like inducible or suicide genes may allow for the controlled proliferation of MSCs and induce apoptosis after their therapeutic task is completed. This review highlights recent advancements in the immortalization of MSCs and the associated risks of tumorigenesis.

Exploration of simultaneous transients between cerebral hemodynamics and the autonomic nervous system using windowed time-lagged cross-correlation matrices: a CENTER-TBI study

BackgroundTraumatic brain injury (TBI) can significantly disrupt autonomic nervous system (ANS) regulation, increasing the risk for secondary complications, hemodynamic instability, and adverse outcome. This retrospective study evaluated windowed time-lagged cross-correlation (WTLCC) matrices for describing cerebral hemodynamics–ANS interactions to predict outcome, enabling identifying high-risk patients who may benefit from enhanced monitoring to prevent complications.MethodsThe first experiment aimed to predict short-term outcome using WTLCC-based convolution neural network models on the Wroclaw University Hospital (WUH) database (Ptraining = 31 with 1,079 matrices, Pval = 16 with 573 matrices). The second experiment predicted long-term outcome, training on the CENTER-TBI database (Ptraining = 100 with 17,062 matrices) and validating on WUH (Pval = 47 with 6,220 matrices). Cerebral hemodynamics was characterized using intracranial pressure (ICP), cerebral perfusion pressure (CPP), pressure reactivity index (PRx), while ANS metrics included low-to-high-frequency heart rate variability (LF/HF) and baroreflex sensitivity (BRS) over 72 h. Short-term outcome at WUH was assessed using the Glasgow Outcome Scale (GOS) at discharge. Long-term outcome was evaluated at 3 months at WUH and 6 months at CENTER-TBI using GOS and GOS-Extended, respectively. The XGBoost model was used to compare performance of WTLCC-based model and averaged neuromonitoring parameters, adjusted for age, Glasgow Coma Scale, major extracranial injury, and pupil reactivity in outcome prediction.ResultsFor short-term outcome prediction, the best-performing WTLCC-based model used ICP-LF/HF matrices. It had an area under the curve (AUC) of 0.80, vs. 0.71 for averages of ANS and cerebral hemodynamics metrics, adjusted for clinical metadata. For long-term outcome prediction, the best-score WTLCC-based model used ICP-LF/HF matrices. It had an AUC of 0.63, vs. 0.66 for adjusted neuromonitoring parameters.ConclusionsAmong all neuromonitoring parameters, ICP and LF/HF signals were the most effective in generating the WTLCC matrices. WTLCC-based model outperformed adjusted neuromonitoring parameters in short-term but had moderate utility in long-term outcome prediction.

Capsular Bag Performance of a Novel Hydrophobic Single-Piece Intraocular Lens.

We conducted an evaluation of capsular bag performance of the Clareon CNA0T0 intraocular lens (IOL), focusing on postoperative anterior chamber depth (ACD), IOL tilt, and IOL decentration. Inclusion criteria were bilateral age-related cataract and the ability to provide informed consent. Exclusion criteria were prior surgeries, combined surgeries, and conditions posing a risk for postoperative capsular bag instability. Preoperative and 8-week postoperative assessments included optical biometry and high-resolution anterior segment optical coherence tomography (OCT). Subjective refraction was conducted only at 8weeks postoperative visit. In the first analysis, 49 right eyes of 49 patients were included. Mean preoperative and postoperative ACD were 3.10 and 4.69mm, respectively. Mean preoperative tilt was 4.77°, increasing to 5.06° postoperatively. Preoperative decentration was 0.16mm, increasing to 0.26mm postoperatively. Absolute refractive error (ARE) was + 0.31D, with 81% of eyes within ± 0.5D limits. In analysis II (98 eyes of 49 patients), both eyes showed a moderate correlation in IOL tilt (Pearson correlation coefficient: 0.27, p = 0.061) and a low correlation in IOL decentration (Pearson correlation coefficient: 0.02, p = 0.892) and ARE (Spearman: 0.15, p = 305) between right and left eyes of the same patient. The Clareon CNA0T0 IOL demonstrated high mechanical stability, with low postoperative tilt and decentration values, resulting in excellent refractive outcomes and visual acuity. These findings confirm the IOL's high stability within the capsular bag and effectiveness in minimizing postoperative refractive error, requiring only minor A-constant adjustments for optimal cataract surgery outcomes. NCT06595693.

Stability evaluation of draft tube tunnels of Palamuru Ranga Reddy lift irrigation scheme lift-Ⅲ, Telangana state, India

Geological and geotechnical evaluation for the 7–9 m diameter and 100 m length, 10 numbers of parallel draft tube tunnels were carried out. The draft tubes are constructed to connect the underground pump house and surge pool for lifting the water. Due to adverse geological conditions and the complex geometry of the structure, a sequential excavation method and controlled blasting were adopted, which minimized the risk of instability during the excavation of the draft tubes. To classify the rock masses and recommendation of support, detailed engineering geological investigations were done. The rocks encountered during the excavation of these tunnels are granites/granitic gneiss which are traversed by mafic dykes of Dharwar Craton. Prominent three to four joint sets were recorded during geological mapping and rock mass shows W-I to W-II weathering grade. For the determination of principal stresses, an in-situ hydrofracturing test was conducted in the borehole. Q-values were determined based on the rock joints and their characteristics, 3D mapping of geological units and stress measurement conducted inside the borehole. The Q-system provides a quantitative assessment of rock mass stability in jointed rock for underground tunnel design and construction. Good stability is indicated by high Q-values, while poor stability is shown by low values. Based on the “Q” system, the entire lengths of the tunnels were characterised as poor to fair rock mass categories. Wedge analysis was conducted along the tunnel alignments using RocScience Unwedge software and accordingly, stability was checked. Engineering geological investigations identified potential geotechnical issues, and corresponding engineering solutions were recommended. A support system was designed based on the Q-system and site-specific geological conditions.

The effect of physical activity lifestyle on in-vivo passive stiffness of the lumbar spine.

The passive stiffness of the lumbar spine has direct implications on one's risk of injury and spinal instability. Therefore, the effects that physical activity lifestyle may have on the lumbar spine's passive stiffness was assessed. Participants were classified as active (n=20) or inactive (n=21) after completing a physical activity questionnaire. Passive lumbar flexion and extension trials were completed on a custom passive jig. The participant's moment-angle curves were determined, and their lumbar spine passive stiffness was analyzed by partitioning the curve into three linear stiffness regions of increasing stiffness. Stiffness in the low stiffness zone of the moment-angle curve was significantly lower in the inactive group (p=0.014). Furthermore, time spent sitting in an office chair significantly predicted the stiffness in their low stiffness zones across all participants (p=0.011). These findings suggest that physical activity lifestyle may be a potential avenue through which one's lumbar spine passive stiffness may increase, improving spinal health and stability in the population.

Impact of lateral ankle sprains on physical function, range of motion, isometric strength and balance in professional soccer players

ObjectiveLateral ankle sprains (LASs) are prevalent in soccer and can affect long-term performance, injury recurrence and risk for chronic ankle instability. This case–control study examined functional impairments associated with LAS...

Микрореконструктивные технологии подшивания интраокулярной линзы к радужке с полным сохранением ее функций

Today, implantation of an intraocular lens (IOL) into the capsular bag is the standard approach to surgical treatment of cataracts and aphakia of various origins. However, there are several reasons and conditions that disallow this operation or increase the risk of instability of the implanted lens, such reasons and conditions including weakness of the lens ligaments; degradation of Zinn's zonule, including dislocation of the IOL‒capsular bag complex post-surgery; damage to or removal of capsular bag during surgery; lack of capsular bag or its destruction during implantation in aphakia cases. To date, problems associated with fixation and centralization of IOL in non-standard cases involving weak or inexistent capsular support remain unresolved. This study aimed to develop techniques allowing to stitch IOL to the iris without compromising its functions in various situations when it is unfeasible or impossible to fix and center lens in the capsular bag. The patients (n = 12; 12 eyes), depending on the clinical situation, were divided into groups: group 1 — dislocations of the IOL–capsular bag complex (6 eyes); group 2 — complete lack of capsular support (3 eyes); group 3 — weakness of capsular support (3 eyes). A special stitching technique was developed for each of these situations. The results of the treatment were good from clinical and functional perspectives: the IOL was fixed securely and centered properly, and the iris's performance and cosmetic aspects were not compromised.

Statistical Evaluation of Uniform Temperature and Thermal Gradients for Composite Girder of Tibet Region Using Meteorological Data

To accurately assess the temperature action and effect of steel-concrete composite girder bridges in plateau and cold areas, this paper investigated nearly 50 years of historical meteorological data from 26 meteorological observation stations in the Tibet region of China. Based on the most unfavorable extreme meteorological data at each meteorological station, a finite element model was used to analyze the temperature field of the composite girder. The most unfavorable values of temperature were obtained. The regional differences in temperature actions at different meteorological stations were analyzed, and the isotherm maps of the extreme values of the uniform temperature and thermal gradients were further obtained based on spatial interpolation methods in the ArcGIS program. The study shows that the uniform temperature is significantly affected by the climatic environment, and the isotherm maps provide a visual representation of the geographic distribution pattern of temperature extremes. The maximum and minimum uniform temperatures in Tibet range from 18.28 °C to 42.27 °C and from −41.07 °C to 4.71 °C respectively. The maximum regional difference of positive and negative thermal gradient reaches 11.32 °C and 7.69 °C respectively. The temperature effects calculated using the most unfavorable values of the isotherm map are all more unfavorable than the specification calculations. In particular, the tensile stress of the concrete under the positive thermal gradient reaches 2.91 MPa, which exceeds the standard value of the tensile strength of concrete. This is a significant risk factor for cracking. The compressive stress of the steel girder under a negative thermal gradient reaches 19.35 MPa, which represents a 136% increase compared to the specified value. This increase elevates the risk of instability in the steel girder.

A Simple Clinical Predictive Model for Arthroscopic Mobility of Osteochondritis Dissecans Lesions of the Knee

Background: Osteochondritis dissecans (OCD) of the knee is a focal idiopathic alteration of subchondral bone and/or its precursor with risk for instability and disruption of adjacent cartilage. Treatment options focused on preventing premature osteoarthritis vary depending on multiple patient and lesion characteristics, including lesion mobility. Purpose: To differentiate lesion mobility before arthroscopy using a multivariable model that includes patient demographic characteristics and physical examination findings. Study Design: Cohort study (Diagnosis); Level of evidence, 2. Methods: Demographic, preoperative physical examination, and radiographic data were collected from a multicenter national prospective cohort of patients with OCD of the knee. Inclusion criteria included patients <19 years of age and patients with arthroscopically confirmed mobility status based on the Research on Osteochondritis Dissecans of the Knee arthroscopy classification. Multivariable logistic regression analysis using stepwise model selection was used to determine factors associated with the likelihood of a mobile versus an immobile lesion. A 75% partition of the data was used for model training, and 25% was used as a validation cohort. Quantitative model fit statistics were computed using the holdout data, including sensitivity, specificity, and the area under the receiver operating characteristic curve (AUC), along with the corresponding 95% CI. Results: A total of 407 patients in the prospective cohort met inclusion criteria, and 62% were male. The mean ± SD age was 13.7 ± 2.2 years, height 161.8 ± 5.3 cm, and weight 59.2 ± 42.2 kg. Arthroscopic evaluation yielded 235 immobile and 172 mobile lesions. Multivariable analysis determined that the best model to predict lesion mobility included chronologic age ≥14 years (P < .001), effusion on physical examination (P < .001), and any loss of range of motion on physical examination (P = .07), while controlling for male sex (P = .38) and weight >54.4 kg (P = .12). In the 25% holdout validation sample (n = 102), a sensitivity of 83%, a specificity of 82%, and an AUC of 0.89 (95% CI, 0.82-0.95) were achieved with these predictive factors. Conclusion: Age, effusion, and loss of motion can predict knee OCD lesion mobility at the time of arthroscopy. Education about lesion mobility can help with surgical planning and patient and family counseling.

Stability performance of pumped-storage units considering elastic water hammer effects in pressurized piping systems: Mechanism analysis and quantitative criterion

The flow characteristics of water columns in pressurized piping systems significantly influence the stability of pumped-storage power stations (PSPSs). However, the complex mathematical representation of the elastic water column often leads to its simplification to a rigid column in stability analyses. This study established elastic and rigid models of a PSPS system based on elastic and rigid water columns, respectively. The stability regions of the governor parameters for these two models were determined and compared. Results indicate that the stability region of the elastic model is smaller than that of the rigid model. Consequently, using a simplified rigid model to evaluate the stability of an actual elastic system would pose potential instability risks. Furthermore, the primary cause of the stability difference between the elastic and rigid models is identified as the water hammer wave velocity. As the wave velocity increases, the stability region of the elastic model expands, eventually approaching that of the rigid model. Lastly, the coupling mechanism between the pressurized pipe and the pumped-storage unit is clarified. The modulus of the water hammer reflection coefficient is proposed to quantify the stability performance of the pumped-storage unit. These findings provide crucial insights for ensuring the stable operation of PSPSs.

Evaluation of the performance and effect of steel fiber reinforced cellular concrete for underwater blast protection under contact explosion loading

The reinforced concrete structure is more likely to be destroyed under the action of underwater explosion load, which makes the overall structure have the risk of instability. The purpose of this paper is to study the underwater anti-explosion protection performance of steel fiber reinforced cellular concrete protective layer. The FEM-SPH coupling method was used to study the underwater damage process, dynamic response, failure mode and protection effect of the protected structure strengthened by eight different proportions of protective layers. The results show that the addition of steel fiber reinforced cellular concrete protective layer can effectively improve the anti-explosion performance of the protected structure, and its anti-explosion performance is directly related to the volume fraction of steel fiber in the protective layer. Under different ratio protection schemes, the total energy absorption and protection rate of the protective layer increase first and then decrease with the increase of the volume fraction of steel fiber in the protective layer, while the peak pressure of the protected structure at the measuring point and the failure volume rate of the whole structure decrease first and then increase. Among them, the underwater wave attenuation and energy consumption effect of SAP10S15 protective layer is the most prominent, and its total energy absorption is 20 % higher than that of other protective layers. Under this ratio protection scheme, the shock wave pressure of the protected structure is greatly attenuated, and the peak pressure of each measuring point is reduced by about 35.8 %, 37.9 %, 23.7 %, 27.9 % and 35.1 % respectively compared with the unprotected scheme. The damage degree of the protected structure under the SAP10S15 ratio protection scheme is significantly reduced. The failure volume rate and damage index are 8.03 % and 0.21, respectively, which are 37.7 % and 42.5 % lower than those of the unprotected scheme. The damage level is reduced from serious damage to moderate damage. In addition, the damage grade prediction curve of the protected structure is constructed, and the predicted value of the curve is in good agreement with the simulation results, which can provide a reference for the rapid evaluation of the underwater explosion-proof performance of the steel fiber reinforced cellular concrete protective layer.

A Study on the Relationship between Physical Properties of Inorganic Materials and Electrochemical Stability in All-Solid-State Li-Metal Batteries

The development of solid-state batteries (SSBs) is crucial for advancing next-generation battery technology. Compared to conventional lithium-ion batteries using organic liquid electrolytes, SSBs offer higher energy density, improved safety, and wide operating temperature range. Nonetheless, constructing a practical SSB with lithium-metal anode (LMA) and optimal inorganic solid electrolyte (SE) presents significant challenges. In this presentation, we introduce our findings addressing the two primary obstacles impeding the remarkable advancement of SSBs.The electrochemical instability at the interface between LMA and SE is the first persistent issue to overcome. Solid materials constituting SSBs exhibit distinct physical and chemical properties. When these materials, in the form of electrodes or electrolytes, are assembled into an electrochemical cell configuration, they establish solid–solid interfaces within the energy storage system. Achieving electrochemically stable SSBs requires non-reactive interfaces between LMA and SE with conformal contact. Previous studies have predominantly focused on developing interface modification methods to enhance the long-term cycling stability of SSBs. However, such approaches often offer phenomenological solutions without a thorough understanding of the interface dynamics. Additionally, the role of charges within an electric field in the operation of lithium-ion batteries is often overlooked. The LMA-SE interface of SSBs experiences an in situ electric field during the charging process, where the SEs exhibit semiconducting properties distinct from liquid electrolytes. Consequently, identifying the governing mechanism of interface stabilization cannot rely solely on conventional electrochemical techniques or a materials science perspective alone.Interface modeling by tailoring energy band alignment is a fundamental approach to achieving the cycling stability of SSBs. In this study, we used Li1.3Al0.3Ti1.7(PO4)3 (LATP), a representative NASICON-type SE, alongside a Li-metal foil. Although LATP possesses excellent electrochemical stability with a high anodic limit (4.31 V) and small decomposition energy (- 65 meV per atom at 5 V), its direct contact with LMA leads to the formation of a reactive interface having mixed ionic-electronic conducting interphases (MCI). The presence of MCI expedites the reduction of LATP’s metallic constituents by enabling electron transfer across the interface. Given the heightened risk of interfacial instability in the electrochemical cell, controlling interfacial reactions is imperative for constructing SSBs. Herein, we deposited titanium (45 nm) onto the surface of LATP to stabilize the inherently reactive LMA-LATP interface. The pure transition metal interlayer transformed into an ion-conducting crystal structure through electrochemical interactions with Li-metal. This titanium compound self-induced interlayer (TSI) served as a stable Li-ion conductor and electron buffer between LMA and LATP. Lithium symmetric cells having TSI maintained constant overpotential over 1000 cycles and exhibited significantly reduced impedance.Another critical obstacle to realizing practical SSBs is the intrinsic structural instability of SEs. This physical instability shortens the lifespan of SSBs and severely diminishes their electrochemical performance at the typical ambient temperatures of electric vehicle power batteries (25-50 °C). Over the past decade, various solid-state Li-ion conductors have been developed such as Li7La3Zr2O12 (garnet-type oxide SE) and Li6PS5Cl (argyrodite-type sulfide SE). By associating lattice dynamics and ionic transport in these materials, previous studies could improve the ionic conductivity of SE through major substitution with large cations like tantalum or partial substitution with large anions. Recently, antiperovskite-type SEs with the anion-centered unit of Li3AB, where A represents hydroxyl and B represents halogen groups, have attracted attention. The representative composition Li2OHCl is renowned for its facile fabrication process through solid-state reaction, high ionic conductivity (10-3 S cm-1), and excellent compatibility with LMA. Still, significant limitations exist in its use for constructing practical SSBs, as is common with most other types of SEs.We found that substituting trace amounts of aliovalent cations to modify atomic interactions in SEs can significantly enhance the electrochemical reliability of SSBs. This strategy effectively resolves the intrinsically unstable structure of SEs and simultaneously enhances the LMA-SE interfaces. As a proof-of-concept, we substituted lithium in Li2OHCl with metal elements that do not experience crystal field stabilization energy. The resulting modified electrolytes led to prolonged lifespan and superior rate performance in lithium symmetric cells at room temperature. The cells with the modified SEs exhibited a remarkable critical current density exceeding 10.5 mA cm-2 and maintained a stable voltage profile for 3000 hours at 10.0 mA cm-2, whereas the pristine cells achieved a relatively low critical current density of 2.0 mA cm-2 and a short lifespan of 1000 hours at 1.0 mA cm-2. These findings underscore a strong correlation between the physical properties of inorganic materials and the electrochemical stability of SSBs. Finally, we anticipate that the revealing results will contribute to the advancement of high-power SSBs employing solid electrolytes and metallic electrodes.