Head Joint Research Articles

Detecting biological motion signals in human and monkey superior colliculus: a subcortical-cortical pathway for biological motion perception.

Most vertebrates, including humans, are highly adept at detecting and encoding biological motion, even when it is portrayed by just a few point lights attached to the head and major joints. However, the function of subcortical regions in biological motion perception has been scarcely explored. Here, we investigate the role of the superior colliculus in local biological motion processing. Using high-field (3 T) and ultra-high-field (7 T) functional magnetic resonance imaging, we record the neural responses of the superior colliculus to scrambled point-light walkers (with local kinematics retained) in both humans and male macaque monkeys. Results show that the superior colliculus, especially the superficial layers, selectively responds to local biological motion. Furthermore, dynamic causal modeling analysis reveals a subcortical-cortical functional pathway that transmits local biological motion signals from the superior colliculus via the middle temporal visual complex to the posterior superior temporal sulcus in the human brain. These findings suggest the existence of a cross-species mechanism in the superior colliculus that facilitates the detection of local biological motion at the early stage of the visual processing stream.

Analytical investigation on the rotational behavior of dovetail mortise–tenon joints between beams and columns in traditional Chinese timber frames

We theoretically analyzed the rotational behavior of beam–column dovetail joints in traditional Chinese timber frames in this study. An analytical model of dovetail joints at both the column head and body was designed by clarifying the moment generation mechanism and effect of rotational embedment yielding in timber perpendicular to the grain on the rotational behavior of joints. An asynchronous manifestation of rotational embedment deformation across the column surface, tenon cheeks, and upper and lower surfaces of the tenon head was analyzed, and the corresponding characteristic yield points and consequent reduction in rotational stiffness were derived in the model. The Inayama embedment theory was used to clarify the effect of rotational embedment with varying end lengths on the movement of the joint rotation center and asymmetric moment generated in different rotation directions of the column head joint. The precision of the analytical model was validated through a comparative analysis by involving nine sets of experimental data, for estimating the initial stiffness, post-yield stiffness, and identified yield points. The implications of the parameters, including the initial gap between the tenon and mortise, geometric dimensions of the dovetail tenon, and friction coefficient, were also discussed. Controlling the ratio of the initial gap and tenon height within 0.01 to ensure a certain rotational resistance of dovetail beam–column joints within the collapse limits of traditional timber frames is recommended considering the significant effect of the initial gap on the initial sliding angle and moment reduction.

Research on the Detection Algorithm of Elderly Falling Behavior Based on AlphaPose Model

This study aims to address the challenge of quickly and accurately detecting high-risk behaviors such as falls in elderly people in hardware environments with limited power consumption and cost. Therefore, this article proposes an optimized behavior anomaly detection algorithm based on the AlphaPose model. The algorithm first improved the human target detection and pose estimation models to achieve faster pedestrian detection and pose joint point inference; Then, using the adjusted AlphaPose model, efficiently obtain the image coordinate data of each joint point in the human body; Finally, by analyzing the relationship between the linear velocities of the human head and hip joints, as well as the changes in the angle between the vertical line of the human center and the X-axis of the image, it is determined whether a fall event has occurred. This study deployed the proposed algorithm on the JetsonNano embedded development board and compared its performance with mainstream fall detection algorithms based on human posture, including YOLOv3+Pose, YOLOv4+Pose, YOLOv5+Pose, trtpose, and NanoDet+Pose. The experimental results show that on the set embedded platform, when the image resolution is 320×240, this algorithm achieves a detection rate of 8.83 frames per second and an accuracy of 0.913, both of which are superior to the compared algorithms. In summary, this algorithm has high real-time performance and accuracy, and can effectively identify the falling behavior of elderly people in a timely manner.

Solid and Homogeneous Thermal Wall of Cored Lightweight Concrete Blocks Solidarized in situ

Abstract: The exterior walls of buildings play a major role in the road for a near-zero energy building. Nowadays, in Portugal, the ETICS system is the most used technology to ensure the thermal insulation of exterior walls of buildings. However, the ETICS system has low resistance to impacts and requires a self-supporting sheet of wall, among other disadvantages. Here, the concept of new technology for exterior walls of residential and commercial buildings is presented. It consists of a hybrid technology for the easy and quick execution of a single sheet wall, which may provide high thermal efficiency for buildings. This hybrid technology relates to parallelepipedshaped cored lightweight concrete blocks comprising two parallel sides separated by one or more solid connectors in which the connectors allow the filling of the block core with lightweight concrete. No bed or head joints are used to connect the blocks because the wall made of cored blocks gets solid and homogeneous when filled with lightweight concrete. When the block thickness is 30 cm and the thermal conductivity of the lightweight concrete is lower than 0.09 W/m.ºC, in Portugal, this type of exterior wall does not require the application of extra thermal insulation materials.

Laboratory Tests of the Area of Head Joints and Bed Joints Increase the Diagonal Shear Stress of Brick Walls

Laboratory Tests of the Area of Head Joints and Bed Joints Increase the Diagonal Shear Stress of Brick Walls

Morphological Changes and Concentricity of the Hip Joint During Gradual Reduction in Infants with Late-Detected Developmental Dysplasia of the Hip: A Retrospective Study.

The relationship between hip morphological changes and joint concentricity in infants with late-detected developmental dysplasia of the hip (DDH) treated with gradual reduction remains unclear. Therefore, we investigated hip morphological changes and concentricity in infants with late-detected unilateral DDH using magnetic resonance imaging (MRI) during gradual reduction. We enrolled 20 infants aged ≥ 12months with unilateral DDH. Treatment comprised continuous traction, a hip-spica cast, and an abduction brace. MRI was performed before treatment, immediately after hip-spica cast placement, after cast removal, and at the end of the brace. We evaluated the acetabulum and femoral head morphology and joint concentricity. The mean age was 25months, and female sex and the left side were predominant. Before treatment, the acetabulum was small and shallow and the femoral head was spherically flat on the affected side. Immediately after the continuous traction, the affected acetabulum and femoral head were still smaller than the healthy/contralateral one. However, they improved to a deeper acetabulum and round femoral head. Intra-articular soft tissue (IAST) and femoral-acetabular distance (FAD) continuously decreased, indicating gradual improvement in joint concentricity. Deeper formation of the acetabulum and round shaping of the femoral head had occurred even in non-concentric reduction. The shape and concentricity of the hip joint improved after treatment; however, the acetabulum and femoral head remained small. The deeper acetabulum and round femoral head were observed the non-concentric reduction before the concentric reduction was achieved. The continuous decrease in IAST and FAD indicates effective post-traction therapy.

A low computation-cost locomotion control for underwater snake robot based on Monte Carlo model predictive control and curvature derivative control

ABSTRACT This work studies the application of a sample-based model Monte Carlo Model Predictive Control (MCMPC) to address discontinuous events, such as collisions. The inclusion of contact dynamics in the prediction steps of MCMPC renders it advantageous for the operation of underwater snake robots in restricted environments during rescue missions. The Curvature Derivative Control (CDC) method is employed for the purpose of controlling the joints, with the exception of the head joint. The snake robot body demonstrates adaptability to various environments with the assistance of the CDC. Results obtained from the simulation demonstrate that the snake robot is capable of autonomously navigating from its beginning position outside the region to a pipe as the entrance in order to get inside. The robot successfully traverses through various internal structures within the pipe and ultimately reaches the intended destination, guided by a predetermined cost function of MCMPC. By using the capabilities of CUDA GPU parallel computing, the computational time is substantially lowered.

Developing a Computer Vision Model to Automate Quantitative Measurement of Hip-Knee-Ankle Angle in Total Hip and Knee Arthroplasty Patients

BackgroundIncreasing deformity of the lower extremities, as measured by the hip-knee-ankle angle (HKAA), is associated with poor patient outcomes after total hip and knee arthroplasty (THA, TKA). Automated calculation of HKAA is imperative to reduce the burden on orthopaedic surgeons. We proposed a detection-based deep learning (DL) model to calculate HKAA in THA and TKA patients and assessed the agreement between DL-derived HKAAs and manual measurement. MethodsWe retrospectively identified 1,379 long-leg radiographs (LLRs) from patients scheduled for THA or TKA within an academic medical center. There were 1,221 LLRs used to develop the model (randomly split into 70% training, 20% validation, and 10% held-out test sets); 158 LLRs were considered “difficult,” as the femoral head was difficult to distinguish from surrounding tissue. There were 2 raters who annotated the HKAA of both lower extremities, and inter-rater reliability was calculated to compare the DL-derived HKAAs with manual measurement within the test set. ResultsThe DL model achieved a mean average precision of 0.985 on the test set. The average HKAA of the operative leg was 173.05 ± 4.54°; the nonoperative leg was 175.55 ± 3.56°. The inter-rater reliability between manual and DL-derived HKAA measurements on the operative leg and nonoperative leg indicated excellent reliability (intraclass correlation (2,k) = 0.987 [0.96, 0.99], intraclass correlation (2, k) = 0.987 [0.98, 0.99, respectively]). The standard error of measurement for the DL-derived HKAA for the operative and nonoperative legs was 0.515° and 0.403°, respectively. ConclusionsA detection-based DL algorithm can calculate the HKAA in LLRs and is comparable to that calculated by manual measurement. The algorithm can detect the bilateral femoral head, knee, and ankle joints with high precision, even in patients where the femoral head is difficult to visualize.

Cervical Spine and Head Joints

Cervical Spine and Head Joints

The Impact of Forward Head Posture on Neck and Ankle Joint Position Sense: A Cross-Sectional Study.

Forward head posture (FHP) decreases the neck position sense and creates tension in the neck muscles, which inversely affects the mechanics of the distal joints through body myofascia. Thus, this study investigated the effects of FHP on neck and ankle joint position sense, and conducted a comparison between the joint position sense of the right and left ankle. Fifty-seven subjects were assigned according to the craniovertebral angle (CVA) into the FHP group (CVA <49°; n = 27) or the control group (CVA >49°; n = 30). Head and ankle joint repositioning accuracy was measured by using a cervical range-of-motion device and an isokinetic dynamometer, respectively. There was a significant increase in the joint position error (JPE) of the cervical flexion, extension, and right and left side bending motions of the FHP group compared to the control group (P < .05). There were significant increases in the JPE of the right and left ankle dorsiflexion and plantarflexion of the FHP group compared to the healthy group (P < .05). Moreover, the JPE of the right ankle dorsiflexion and plantarflexion of the FHP group were significantly higher than the left ankle (P < .05). The FHP decreases the position sense of cervical flexion, extension, and right and left side bending motions, and the plantarflexion and dorsiflexion of both ankle joints, especially the right ankle joint.

Comparative Analysis of Hyaline Cartilage Characteristics and Chondrocyte Potential for Articular Cartilage Repair.

This study aimed to compare the histological, biochemical, and mechanical characteristics of hyaline cartilage in different regions and evaluate the potential of chondrocytes extracted from each region as donor sources for articular cartilage repair. The cartilage tissues of the femoral head and knee joint, ribs, nasal septum, thyroid, and xiphoid process of adult Bama pigs were isolated for histological, biochemical, and mechanical evaluation and analysis. The corresponding chondrocytes were isolated and evaluated for proliferation and redifferentiation capacity, using biochemical and histological analysis and RT-PCR experiments. Compared with articular cartilage, non-articular hyaline cartilage matrix stained more intensely in Safranin-O staining. Glycosaminoglycan and total collagen content were similar among all groups, while the highest content was measured in nasal septal cartilage. Regarding biomechanics, non-articular cartilage is similar to articular cartilage, but the elastic modulus and hardness are significantly higher in the middle region of costal cartilage. The chondrocytes extracted from different regions had no significant difference in morphology. Hyaline cartilage-like pellets were formed in each group after redifferentiation. The RT-PCR results revealed similar expressions of cartilage-related genes across the groups, albeit with lower expression of Col2 in the xiphoid chondrocytes. Conversely, higher expression of Col10 was observed in the chondrocytes from the rib, thyroid, and xiphoid cartilage. This study provides valuable preclinical data for evaluating heterotopic hyaline cartilage and chondrocytes for articular cartilage regeneration. The findings contribute to the selection of chondrocyte origins and advance the clinical translation of technology for cartilage regeneration.

Analysis of influence of MR signs on Harris score in ARCO stages 2-4 femoral head necrosis

To analysis and determine MR signs of Harris score ARCO stages 2-4 in osteonecrosis of femoral head (ONFH). Thirty-four patients with ONFH of ARCO stages 2 to 4 who underwent routine MR, T2 mapping, 3D-SPACE sequence examination and Harris score were retrospectively collected from January 2019 to June 2020, and 3 patients were excluded, and 31 patients were finally included, including 23 males and 8 females, aged from 18 to 62 years old with an average of(40.0±10.8) years old. Among them 21 patients with bilateral femoral head necrosis, totally 52 cases, including 17 with ARCO stage 2 patients, 24 ARCO stage 3, and 11 ARCO stage 4. MR imaging signs (femoral head collapse depth, ONFH index, bone marrow edema, hyperplasia, grade and T2 value of cartilage injury, and joint effusion) were scored and measured on the picture archiving and communication system (PACS) workstation, and the cartilage quantitative parameter T2 value was calculated and measured on Siemens postprocessing workstation. Pearson correlation analysis was used to evaluate the correlation between various MR signs and Harris score, and then multiple linear regression analysis was used to examine impact of MR signs on Harris hip score. Femoral head collapse depth(r=-0.563, P=0.000), grade of cartilage injury(r=-0.500, P=0.000), and joint effusion (r=-0.535, P=0.000) were negatively correlated with Harris score by Pearson correlation analysis. Multiple linear regression analysis showed that joint effusion(β=-6.198, P=0.001) and femoral head collapse depth(β=-4.085, P=0.014) had a significant negative impact on Harris hip score. Femoral head collapse depth and joint effusion both had significant negative relationship with Harris hip score. It is recommended to routinely evaluate femoral head collapse depth and joint effusion quantitatively and gradedly, so as to efficiently and accurately assist clinical diagnosis and treatment.

Experimental investigation of the influence of head joints and grouting conditions on the shear strength of concrete block masonry

The nonlinear composite nature of masonry has limited theoretical understanding of material shear strength – especially with concrete block, where minimal experimentation has rendered the influences of two important variables (head joints, presence of grout) unknown. The effects of these variables were investigated experimentally on non-precompressed triplet specimens. Head joints did not influence shear strength statistically significantly: the proportion of grouted cores linearly increased shear strength. The provisions in the Canadian standard lacked accuracy when predicting partially grouted specimen strengths (overestimating up to 135%). Units from tested triplet specimens were also found to have similar compressive strengths to undisturbed units.

Efficiency evaluation of a commercial superficial strengthening system applied to AAC-block walls under diagonal compression

The article presents the influence of a superficial strengthening system on the behaviour of AAC-block walls with thin bed joints and unfilled head joints. The strengthening system consisted of a high-strength fibreglass mesh applied to both wall surfaces with a mineral mortar reinforced with fibreglass. A series of strengthened and unstrengthened specimens was tested under diagonal compression according to ASTM E519-15 to determine their shear strength and stress-strain characteristics. The use of optical strain measurement made it possible to identify the failure mode for both types of the tested walls. The strengthening system changed the wall failure development, which was initiated by unfilled head joints in both cases. The application of the strengthening system on both wall surfaces improved the strength properties of the wall significantly. The load-bearing capacity of the specimens increased by nearly 90% and cracking of the walls occurred at loads about 50% higher compared to specimens with no superficial strengthening. The strengthened specimens exhibited a ductile behaviour after reaching the maximum bearing capacity. A simplified method for computing the cracking load and maximum load was also proposed, the results of which are consistent with the tests results.

Active Confinement of Masonry Walls with Stainless Steel Straps: The Effect of Strap Arrangement on the in-Plane Behavior of Strength, Poisson’s Ratio, and Pseudo-Ductility

Among all the active confinement techniques, the use of pre-tensioned stainless steel straps has recently gained much attention. The flexibility of the stainless steel straps allows us to bend and pass them through the thickness of the masonry, thus creating a three-dimensional strengthening system between the two opposite facings. The use of the same perforation for the passage of several straps closed in a loop generates a continuous strengthening system that prevents parts of the structure from falling and injuring the occupants during seismic events. However, the perforations can nullify the in-plane strengthening, as they act as cylindrical hinges and make the reinforcement system labile for certain strap arrangements. Diagonal compression tests on square masonry panels performed in the present study show that the straps improve neither strength nor ductility when running along the mortar head and bed joints, arranged in square meshes. Conversely, they improve both strength and ductility when the straps make angles of ±45° with the mortar joints. Furthermore, the experimental results show that the straps exert an anisotropic effect that decreases the apparent in-plane Poisson ratio. They also provide new insights into the diagonal compression test and allow formulating a new proposal for the pseudo-ductility factor.

Preseason Measures of Cervical Spine Function, Vestibulo-Ocular Reflex, Dynamic Balance, and Divided Attention in Youth Ice Hockey Players.

OBJECTIVES: Report typical scores and examine preseason cervical spine, vestibulo-ocular reflex, dynamic balance, and divided attention measures in competitive youth ice hockey players aged 10 to 18 years with and without a previous concussion history. DESIGN: Cross-sectional secondary analysis. METHODS: The exposure of interest was self-reported history of concussion. The main outcomes were cervical spine measures (Cervical Flexor Endurance [CFE; seconds], Cervical Flexion-Rotation Test [normal/abnormal], Anterolateral Cervical Spine Strength [kilograms], Head Perturbation Test (/8), and Joint Position Error [JPE; centimeters]), vestibulo-ocular reflex (Dynamic Visual Acuity [logMAR], Head Thrust Test [Positive/Negative]), dynamic balance (Functional Gait Assessment [/30]) and divided attention (Walking While Talking Test [seconds]). Multivariable linear or logistic regression, adjusted for age-group, sex, level of play, and clustered by team, were used to assess potential differences by concussion history. RESULTS: We included data from 2311 participants in this study (87.2% male, 12.8% female, 39.0% reported a previous concussion). No differences by concussion history were found across any of the measures (P values range: 0.17-0.99). Measures of cervical spine function and divided attention differed by age group (eg, Median Left Anterolateral Cervical Spine Strength [kilograms] for males: U13 = 7.46, U15 = 9.10, U18 = 9.67). CONCLUSION: Clinical outcomes scores in youth ice hockey players did not differ by concussion history. Performance on cervical spine strength, CFE, and JPE test outcomes may improve with age, highlighting the importance of developmental considerations when interpreting test scores. J Orthop Sports Phys Ther 2024;54(3):1-11. Epub 30 November 2023. doi:10.2519/jospt.2023.11958.

Intertrochanteric curved varus osteotomy for subchondral fracture of the femoral head: a case series

Although favorable results have been reported with total hip arthroplasty, joint-preserving treatment should be the first choice for subchondral fracture of the femoral head (SFF) in young patients. This study reviewed four young male patients with SFF who underwent intertrochanteric curved varus osteotomy (CVO). The patients had a mean age of 32.3 years (range: 18–49 years). Conservative treatment was initially attempted in all cases, but failed to alleviate the pain, leading to surgical intervention at an average time of 6 months (range: 4–10 months) after symptom onset. As the fracture sites were located medial to the lateral edge of the acetabulum in all cases, CVO was performed to achieve a postoperative intact ratio of ≥ 34% in the weight-bearing region of the femoral head. The average follow-up period after surgery lasted 4.3 years (range: 2–7 years). Clinical and radiographic assessments were performed pre- and postoperatively. At the latest follow-up, the mean Harris hip score improved from 67.3 preoperatively to 99.5 postoperatively. The average preoperative intact ratio of the weight-bearing region of the femoral head was 12.3%, which increased to 44.3% postoperatively. No progression to femoral head collapse or joint space narrowing was observed on the plain radiographs. CVO is a simple, less-invasive, and beneficial approach for treating SFF in young patients whose fractures occur medial to the lateral edge of the acetabulum.

Comprehensive studies of the influence of superficial strengthening with the FRCM system on the load‐bearing capacity and deformability of AAC walls

AbstractThis article presents the results of tests on walls made of AAC (autoclaved aerated concrete) strengthened with the FRCM system. The effect of the applied strengthening was determined based on the results of tests on masonry models subjected to compression, diagonal compression and shear. Models of walls without strengthening, strengthened on one and two sides were tested. The research models were built of masonry elements made of autoclaved aerated concrete (AAC) SOLBET OPTIMAL 4/600. The walls were erected on a system thin‐layer mortar, class M5, without filling the head joints. PBO fiber meshes embedded in a mineral matrix were used as superficial reinforcement. The walls were strengthened by applying the PBO‐MX GOLD MASONRY system mortar to the side surfaces of the models and the PBO‐MESH GOLD 22/22 mesh was embedded in it, and then the top layer of the PBO‐MX GOLD MASONRY system mortar was applied. The compressive strength test was performed on 18 models in accordance with the requirements of the PN‐EN 1052‐1: 2000 standard. In the case of compression, additional tests were performed on models weakened by a cut imitating cracking. The diagonal compression test was performed on 18 models in accordance with the requirements of ASTM E519‐81 standard. The shear load test was performed on 27 models in accordance with the requirements of the PN‐EN 1052–3: 2004 standard. A clear increase in load capacity in each type of test was noted in models strengthened on two sides. In models strengthened on one side, the positive effect of strengthening was observed only by increasing the deformability of the wall. Regardless of the test type, the use of surface reinforcement allowed for smoother behavior of the test models after the loss of load capacity in relation to models without strengthening.

Is tranexamic acid safe for the hip joint?

To show the effects of tranexamic acid, which is a drug frequently used to control bleeding, on the hip joint and sciatic nerve in animal experiments. There were 15 rats in each of the 3 groups, with a total of 45 rats. Topical saline injections were applied to the first group, topical TXA injections to the second group, and intravenous (IV) TXA injections to the third group. In the samples taken from the hip joint 3weeks later, femoral head cartilage, sciatic nerve, and joint capsule thicknesses were analyzed histologically. Statistically significantly more cartilage degradation was detected in the femoral head cartilage in both the IV and intraarticular TXA group when compared to the control group. The groups were also compared in terms of acetabular cartilage; however, no histological difference was found between the groups. It was seen that when the femoral head cartilage thickness (the average of the measurements made from 3 different points were used) was examined, the cartilage thickness in the topical TXA group was less when compared to the other 2 groups. However, this difference was determined to not be statistically significant. The data of the hip joint capsule thickness measurement, it was found that the capsule thickness in the topical TXA applied group was less when compared to the other 2 groups. However, this difference was not statistically significant. When the sciatic nerves in all 3 groups were compared, no different staining characteristics were found in the immunofluorescence examination. TXA, which is frequently used in orthopedic practice, shows negative effects on hip joint cartilage in both topical and intravenous application.

Effect of Cessna 172S Aircraft Engine Vibration on the ground on Aviator Academy Pilots

&#x0D; &#x0D; &#x0D; &#x0D; There are various problems experienced by cadets at the Indonesian Aviator Academy (API) Banyuwangi, one of which is the effect of engine vibrations on the pilot of the cessna 172s aircraft. Vibration is a physical factor in the workplace that comes from the work equipment used. The impact of vibration on humans mainly occurs in certain parts of organs such as: chest, head, jaw, nerves and other joints. In general, exposure to mechanical vibrations in the body can cause disturbances in comfort at work, accelerate the occurrence of work fatigue and the emergence of disturbances to occupational health. The discomfort that affects the cadets at the Indonesian Aviator Academy (API) Banyuwangi affects the causes of fatigue that can cause plane crashes. This study aims to determine the effect of engine vibration on the performance of the pilot of the cessna 172s aircraft. The results of this study were based on questionnaire data obtained from cadets, 50% of 25 respondents answered that they had felt numbness in the hands when holding the steering lever of the aircraft and felt anxious when there was excessive vibration. The condition experienced can be a safety risk for pilots and cadets if the existing problem is not quickly given a solution to the solution.&#x0D; &#x0D; &#x0D; &#x0D;