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1.
Sci Rep ; 12(1): 13232, 2022 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-35918487

RESUMO

Passive translational tibiofemoral laxity has been extensively examined in posterior cruciate ligament (PCL) insufficient patients and belongs to the standard clinical assessment. However, objective measurements of passive rotational knee laxity, as well as range of tibiofemoral motion during active movements, are both not well understood. None of these are currently quantified in clinical evaluations of patients with PCL insufficiency. The objective of this study was to quantify passive translational and rotational knee laxity as well as range of anterior-posterior and rotational tibiofemoral motion during level walking in a PCL insufficient patient cohort as a basis for any later clinical evaluation and therapy. The laxity of 9 patient knees with isolated PCL insufficiency or additionally posterolateral corner (PLC) insufficiency (8 males, 1 female, age 36.78 ± 7.46 years) were analysed and compared to the contralateral (CL) knees. A rotometer device with a C-arm fluoroscope was used to assess the passive tibiofemoral rotational laxity while stress radiography was used to evaluate passive translational tibiofemoral laxity. Functional gait analysis was used to examine the range of anterior-posterior and rotational tibiofemoral motion during level walking. Passive translational laxity was significantly increased in PCL insufficient knees in comparison to the CL sides (15.5 ± 5.9 mm vs. 3.7 ± 1.9 mm, p < 0.01). Also, passive rotational laxity was significantly higher compared to the CL knees (26.1 ± 8.2° vs. 20.6 ± 5.6° at 90° knee flexion, p < 0.01; 19.0 ± 6.9° vs. 15.5 ± 5.9° at 60° knee flexion, p = 0.04). No significant differences were observed for the rotational (16.3 ± 3.7° vs. 15.2 ± 3.6°, p = 0.43) and translational (17.0 ± 5.4 mm vs. 16.1 ± 2.8 mm, p = 0.55) range of anterior-posterior and rotational tibiofemoral motion during level walking conditions for PCL insufficient knees compared to CL knees respectively. The present study illustrates that patients with PCL insufficiency show a substantial increased passive tibiofemoral laxity, not only in tibiofemoral translation but also in tibiofemoral rotation. Our data indicate that this increased passive multiplanar knee joint laxity can be widely compensated during level walking. Further studies should investigate progressive changes in knee joint laxity and kinematics post PCL injury and reconstruction to judge the individual need for therapy and effects of physiotherapy such as quadriceps force training on gait patterns in PCL insufficient patients.


Assuntos
Instabilidade Articular , Ligamento Cruzado Posterior , Adulto , Fenômenos Biomecânicos , Feminino , Humanos , Articulação do Joelho , Masculino , Amplitude de Movimento Articular , Rotação , Tíbia/cirurgia , Caminhada
2.
J Vis ; 22(8): 1, 2022 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-35816048

RESUMO

Psychophysical, motor control, and modeling studies have revealed that sensorimotor reference frame transformations (RFTs) add variability to transformed signals. For perceptual decision-making, this phenomenon could decrease the fidelity of a decision signal's representation or alternatively improve its processing through stochastic facilitation. We investigated these two hypotheses under various sensorimotor RFT constraints. Participants performed a time-limited, forced-choice motion discrimination task under eight combinations of head roll and/or stimulus rotation while responding either with a saccade or button press. This paradigm, together with the use of a decision model, allowed us to parameterize and correlate perceptual decision behavior with eye-, head-, and shoulder-centered sensory and motor reference frames. Misalignments between sensory and motor reference frames produced systematic changes in reaction time and response accuracy. For some conditions, these changes were consistent with a degradation of motion evidence commensurate with a decrease in stimulus strength in our model framework. Differences in participant performance were explained by a continuum of eye-head-shoulder representations of accumulated motion evidence, with an eye-centered bias during saccades and a shoulder-centered bias during button presses. In addition, we observed evidence for stochastic facilitation during head-rolled conditions (i.e., head roll resulted in faster, more accurate decisions in oblique motion for a given stimulus-response misalignment). We show that perceptual decision-making and stochastic RFTs are inseparable within the present context. We show that by simply rolling one's head, perceptual decision-making is altered in a way that is predicted by stochastic RFTs.


Assuntos
Tomada de Decisões , Movimentos Sacádicos , Tomada de Decisões/fisiologia , Humanos , Estimulação Luminosa , Tempo de Reação , Rotação
3.
Sensors (Basel) ; 22(13)2022 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-35808490

RESUMO

Structural Health Monitoring (SHM) is critical in the observation and analysis of our national infrastructure of bridges. Due to the ease of measuring bridge rotation, bridge SHM using rotation measurements is becoming more popular, as even a single DC accelerometer placed at each end of span can accurately capture bridge deformations. Event detection methods for SHM typically entail additional instrumentation, such as strain gauges or continuously recording video cameras, and thus the additional cost limits their utility in resource-constrained environments and for wider deployment. Herein, we present a more cost-effective event detection method which exploits the existing bridge rotation instrumentation (tri-axial MEMS accelerometers) to also act as a trigger for subsequent stages of the SHM system and thus obviates the need for additional vehicle detection equipment. We show how the generalised variance over a short sliding window can be used to robustly discriminate individual vehicle loading events, both in time and magnitude, from raw acceleration data. Numerical simulation results examine the operation of the event detector under varying operating conditions, including vehicle types and sensor locations. The method's application is demonstrated for two case studies involving in-service bridges experiencing live free-flow traffic. An initial implementation on a Raspberry Pi Zero 2 shows that the proposed functionality can be realised in less than 400 ARM A32 instructions with a latency of 47 microseconds.


Assuntos
Aceleração , Acelerometria , Monitorização Fisiológica , Rotação
4.
Comput Math Methods Med ; 2022: 1400658, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35844451

RESUMO

A substantial amount of maintenance and fault data is not properly utilized in the daily maintenance of pantographs in urban metro cars. Pantograph fault analysis can begin with three factors: the external environment, internal flaws, and joint behavior. Based on the analysis of pantograph fault types, corresponding measures are proposed in terms of pantograph fault handling and maintenance strategies, in order to provide safety guarantee for the safe and effective realization of rail transit vehicle speed-up and also provide reference for the maintenance and overhaul of pantographs. For the problem of planned maintenance no longer meeting current pantograph maintenance requirements, a defect diagnosis system based on a combination of faster R-CNN neural networks is presented. The pantograph image features are extracted by introducing an alternative to the original feature extraction module that can extract deep-level image features and achieve feature reuse, and the data transformation operations such as image rotation and enhancement are used to expand the sample set in the experiment to enhance the detection effect. The simulation results demonstrate that the diagnosis procedure is quick and accurate.


Assuntos
Ferrovias , Simulação por Computador , Humanos , Redes Neurais de Computação , Rotação
5.
Nat Commun ; 13(1): 4177, 2022 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-35853940

RESUMO

Soft magneto-active machines capable of magnetically controllable shape-morphing and locomotion have diverse promising applications such as untethered biomedical robots. However, existing soft magneto-active machines often have simple structures with limited functionalities and do not grant high-throughput production due to the convoluted fabrication technology. Here, we propose a facile fabrication strategy that transforms 2D magnetic sheets into 3D soft magneto-active machines with customized geometries by incorporating origami folding. Based on automated roll-to-roll processing, this approach allows for the high-throughput fabrication of soft magneto-origami machines with a variety of characteristics, including large-magnitude deploying, sequential folding into predesigned shapes, and multivariant actuation modes (e.g., contraction, bending, rotation, and rolling locomotion). We leverage these abilities to demonstrate a few potential applications: an electronic robot capable of on-demand deploying and wireless charging, a mechanical 8-3 encoder, a quadruped robot for cargo-release tasks, and a magneto-origami arts/craft. Our work contributes for the high-throughput fabrication of soft magneto-active machines with multi-functionalities.


Assuntos
Locomoção , Rotação
6.
Neural Netw ; 153: 496-517, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35816861

RESUMO

Random Forest is an ensemble of decision trees based on the bagging and random subspace concepts. As suggested by Breiman, the strength of unstable learners and the diversity among them are the ensemble models' core strength. In this paper, we propose two approaches known as oblique and rotation double random forests. In the first approach, we propose rotation based double random forest. In rotation based double random forests, transformation or rotation of the feature space is generated at each node. At each node different random feature subspace is chosen for evaluation, hence the transformation at each node is different. Different transformations result in better diversity among the base learners and hence, better generalization performance. With the double random forest as base learner, the data at each node is transformed via two different transformations namely, principal component analysis and linear discriminant analysis. In the second approach, we propose oblique double random forest. Decision trees in random forest and double random forest are univariate, and this results in the generation of axis parallel split which fails to capture the geometric structure of the data. Also, the standard random forest may not grow sufficiently large decision trees resulting in suboptimal performance. To capture the geometric properties and to grow the decision trees of sufficient depth, we propose oblique double random forest. The oblique double random forest models are multivariate decision trees. At each non-leaf node, multisurface proximal support vector machine generates the optimal plane for better generalization performance. Also, different regularization techniques (Tikhonov regularization, axis-parallel split regularization, Null space regularization) are employed for tackling the small sample size problems in the decision trees of oblique double random forest. The proposed ensembles of decision trees produce trees with bigger size compared to the standard ensembles of decision trees as bagging is used at each non-leaf node which results in improved performance. The evaluation of the baseline models and the proposed oblique and rotation double random forest models is performed on benchmark 121 UCI datasets and real-world fisheries datasets. Both statistical analysis and the experimental results demonstrate the efficacy of the proposed oblique and rotation double random forest models compared to the baseline models on the benchmark datasets.


Assuntos
Algoritmos , Máquina de Vetores de Suporte , Análise de Componente Principal , Rotação
7.
Phys Chem Chem Phys ; 24(29): 17632-17640, 2022 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-35833615

RESUMO

Fluorescent emitters with the hot exciton mechanism combined with aggregation induced emission (AIE) character show prospective applications in organic light emitting diodes (OLEDs). However, theoretical studies on amorphous states are limited. In this work, a theoretical study is performed on the photophysical properties of the reported compound 4-(7-(10-ethyl-10H-phenothiazin-3-yl)benzo[c][1,2,5]thiadiazol-4-yl)-N,N-diphenylaniline (PBTPA), which possesses a hot exciton mechanism and AIE. The aggregation states of this molecule in a film are given by molecular dynamics (MD) simulations, and then the photophysical properties are studied by using the QM/MM method with the consideration of the solid-state effect (SSE). The results explain the hot exciton and AIE mechanism of the molecule. First, there is a hot exciton channel between the S1 and T2 state of the PBTPA. Second, the conformational changes of PBTPA between the ground state and the excited state are restricted in the aggregate state. Last, in the low frequency region, the rotation motion is suppressed, and then the reorganization energy and Huang-Rhys (HR) factor in the aggregate state are much smaller. Therefore, the molecules show strong fluorescence efficiency in the aggregated state.


Assuntos
Simulação de Dinâmica Molecular , Rotação
8.
Biophys J ; 121(15): 2952-2961, 2022 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-35773996

RESUMO

Chirality is a common and essential characteristic at varied scales of living organisms. By adapting the rotational clutch-filament model we previously developed, we investigate the effect of torque relaxation of a formin on cellular chiral swirling. Since it is still unclear how the torque on a formin is exactly relaxed, we probe three types of torque relaxation, as suggested in the literature. Our analysis indicates that, when a formin periodically undergoes positive and negative rotation during processive capping to relax the torque, cells hardly rotate. When the switch between the positive and the negative rotation during the processive capping is randomly regulated by the torque, our analysis indicates that cells can only slightly rotate either counterclockwise or clockwise. When a formin relaxes the torque by transiently loosening its contact either with the membrane at its anchored site or with the actin filament, we find that cells can prominently rotate either counterclockwise or clockwise, in good consistency with the experiment. Thus, our studies indicate that how the torque on a formin is relaxed strongly affects cellular swirling and suggest an efficient type of torque relaxation in switching cellular swirling.


Assuntos
Citoesqueleto de Actina , Actinas , Forminas , Rotação , Torque
9.
Med Biol Eng Comput ; 60(8): 2133-2157, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35776374

RESUMO

Passive spinal stiffness is an important property thought to play a significant role in controlling spinal position and movement. Measuring through-range passive stiffness in vivo is challenging with several methods offered in the literature. Currently, no synthesis of values or methods exists to which to compare literature to. This study aims to provide a contemporary review and quantitative synthesis of the through-range in vivo passive lumbar spinal stiffness values for each of the cardinal planes of movement. A structured systematic search, following PRISMA guidelines, of 28 electronic databases was conducted in 2022. Articles were restricted to peer-reviewed English language studies investigating in vivo through-range passive stiffness of the lumbar spine. Thirteen studies were included, ten relating to flexion/extension, four to lateral bending and five to axial rotation. Average stiffness values, as weighted means and confidence intervals, for each of the four sections of the moment-movement curves were synthesised for all planes of movement. Lateral bending was found to be the comparatively stiffest movement followed by flexion and then axial rotation. Future research should focus on the validity and reliability of measurement techniques. Axial rotation would also benefit from further study of its latter stages of range.


Assuntos
Vértebras Lombares , Fenômenos Biomecânicos , Amplitude de Movimento Articular , Reprodutibilidade dos Testes , Rotação
10.
Proc Natl Acad Sci U S A ; 119(33): e2209164119, 2022 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-35878056

RESUMO

Voltage-gated sodium (Nav) channel Nav1.7 has been targeted for the development of nonaddictive pain killers. Structures of Nav1.7 in distinct functional states will offer an advanced mechanistic understanding and aid drug discovery. Here we report the cryoelectron microscopy analysis of a human Nav1.7 variant that, with 11 rationally introduced point mutations, has a markedly right-shifted activation voltage curve with V1/2 reaching 69 mV. The voltage-sensing domain in the first repeat (VSDI) in a 2.7-Å resolution structure displays a completely down (deactivated) conformation. Compared to the structure of WT Nav1.7, three gating charge (GC) residues in VSDI are transferred to the cytosolic side through a combination of helix unwinding and spiral sliding of S4I and ∼20° domain rotation. A conserved WNФФD motif on the cytoplasmic end of S3I stabilizes the down conformation of VSDI. One GC residue is transferred in VSDII mainly through helix sliding. Accompanying GC transfer in VSDI and VSDII, rearrangement and contraction of the intracellular gate is achieved through concerted movements of adjacent segments, including S4-5I, S4-5II, S5II, and all S6 segments. Our studies provide important insight into the electromechanical coupling mechanism of the single-chain voltage-gated ion channels and afford molecular interpretations for a number of pain-associated mutations whose pathogenic mechanism cannot be revealed from previously reported Nav structures.


Assuntos
Dor , Microscopia Crioeletrônica , Humanos , Mutação , Rotação
11.
J Orthop Surg Res ; 17(1): 362, 2022 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-35883141

RESUMO

PURPOSE: This study was carried out to investigate the accuracy of referring different locations of the patellar tendon attachment site and the geometrical center of the osteotomy surface for tibial rotational alignment and observe the influences of gender differences on the results. METHODS: Computed tomography scans of 135 osteoarthritis patients (82 females and 53 males) with varus deformity was obtained to reconstruct three-dimensional (3D) models preoperatively. The medial boundary, medial one-sixth, and medial one-third of the patellar tendon attachment site were marked on the tibia. These points were projected on the tibial osteotomy plane and connected to the geometrical center (GC) of the osteotomy plane or the middle of the posterior cruciate ligament (PCL) to construct six tibial rotational axes (Akagi line, MBPT, MSPT1, MSPT2, MTPT1 and MTPT2). The mismatch angle between the vertical line of the SEA projected on the proximal tibial osteotomy surface and six different reference axes was measured. In additional, the effect of gender differences on rotational alignment for tibial component were assessed. RESULTS: Relative to the SEA, rotational mismatch angles were - 1.8° ± 5.1° (Akagi line), - 2.5° ± 5.3° (MBPT), 2.8° ± 5.3° (MSPT1), 4.5° ± 5.4° (MSPT2), 7.3° ± 5.4° (MTPT1), and 11.6° ± 5.8° (MTPT2) for different tibial rotational axes in all patients. All measurements differed significantly between the male and female. The tibial rotational axes with the least mean absolute deviation for the female or male were Akagi line or MSPT, respectively. There was no significant difference in whether the GC of the osteotomy surface or the midpoint of PCL termination was chosen as the posterior anatomical landmark when the medial boundary or medial one-sixth point of the patellar tendon attachment site was selected as the anterior anatomical landmark. CONCLUSION: When referring patellar tendon attachment site as anterior anatomical landmarks for tibial rotational alignment, the influence of gender difference on the accuracy needs to be taken into account. The geometric center of the tibial osteotomy plane can be used as a substitute for the middle of the PCL termination when reference the medial boundary or medial one-sixth of the patellar tendon attachment site.


Assuntos
Artroplastia do Joelho , Osteoartrite do Joelho , Ligamento Patelar , Artroplastia do Joelho/métodos , Feminino , Humanos , Articulação do Joelho/diagnóstico por imagem , Articulação do Joelho/cirurgia , Masculino , Osteoartrite do Joelho/diagnóstico por imagem , Osteoartrite do Joelho/cirurgia , Ligamento Patelar/diagnóstico por imagem , Ligamento Patelar/cirurgia , Rotação , Fatores Sexuais , Tíbia/diagnóstico por imagem , Tíbia/cirurgia
13.
PLoS One ; 17(6): e0269336, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35653348

RESUMO

A preliminary exploration of technical methodology for dynamic analysis of scaphoid, capitate, and lunate during unconstrained movements is performed in this study. A heavily accelerated and fat-saturated 3D Cartesian MRI acquisition was used to capture temporal frames of the unconstrained moving wrist of 5 healthy subjects. A slab-to-volume point-cloud based registration was then utilized to register the moving volumes to a high-resolution image volume collected at a neutral resting position. Comprehensive in-silico error analyses for different acquisition parameter settings were performed to evaluate the performance limits of several dynamic metrics derived from the registration parameters. Computational analysis suggested that sufficient volume coverage for the dynamic acquisitions was reached when collecting 12 slice-encodes at 2.5mm resolution, which yielded a temporal resolution of and 2.6 seconds per volumetric frame. These acquisition parameters resulted in total in-silico errors of 1.9°±1.8° and 3°±4.6° in derived principal rotation angles within ulnar-radial deviation and flexion-extension motion, respectively. Rotation components of the carpal bones in the radius coordinate system were calculated and found to be consistent with earlier 4D-CT studies. Temporal metric profiles derived from ulnar-radial deviation motion demonstrated better performance than those derived from flexion/extension movements. Future work will continue to explore the use of these methods in deriving more complex dynamic metrics and their application to subjects with symptomatic carpal dysfunction.


Assuntos
Osso Escafoide , Fenômenos Biomecânicos , Humanos , Imageamento por Ressonância Magnética , Amplitude de Movimento Articular , Rotação , Osso Escafoide/diagnóstico por imagem
14.
J Phys Chem B ; 126(24): 4520-4530, 2022 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-35675630

RESUMO

Water dynamics is essential to biochemical processes by mediating all such reactions, including biomolecular degeneration in solutions. To disentangle the molecular-scale distribution of water dynamics around a solute biomolecule, we investigated here the rotational dynamics of water around lysozyme by combining molecular dynamics (MD) simulations and broadband dielectric spectroscopy (BDS). A statistical analysis using the relaxation times and trajectories of every single water molecule was proposed, and the two-dimensional probability distribution of water at a distance from the lysozyme surface with a rotational relaxation time was given. For the observed lysozyme solutions of 34-284 mg/mL, we discovered that the dielectric relaxation time obtained from this distribution agrees well with the measured γ relaxation time, which suggests that rotational self-correlation of water molecules underlies the gigahertz domain of the dielectric spectra. Regardless of protein concentration, water rotational relaxation time versus the distance from the lysozyme surface revealed that the water rotation is severely retarded within 3 Å from the lysozyme surface and is nearly comparable to pure water when farther than 10 Å. The dimension of the first hydration layer was subsequently identified in terms of the relationship between the acceleration of water rotation and the distance from the protein surface.


Assuntos
Simulação de Dinâmica Molecular , Muramidase , Água , Muramidase/química , Rotação , Soluções/química , Processos Estocásticos , Água/química
15.
J Appl Clin Med Phys ; 23(7): e13661, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35666629

RESUMO

For Elekta Agility linear accelerators, the iViewGT electronic portal imaging device (EPID) is positioned at a nominal X-Ray source-to-panel distance of 1600 mm. For display, image registration, and data processing purposes, the image pixels are scaled to spatial units at the treatment isocenter plane. This is achieved by applying a pixel scaling factor (PSF). During this investigation, the dependence of the PSF at cardinal gantry angles was determined along with the resulting effects on the multi-leaf collimator (MLC) quality assurance (QA) results for three linear accelerators (linacs). The PSF was found to vary by 0.0018-0.0022 mm/pixel during gantry rotation, which resulted in variations in the mean MLC reported error of up to 0.8 mm at 100 mm off-axis with the gantry rotated to 180°. Measurement and application of a gantry angle-specific PSF is a simple process that can be implemented to improve the accuracy of EPID-based MLC QA at cardinal gantry angles.


Assuntos
Equipamentos e Provisões Elétricas , Aceleradores de Partículas , Eletrônica , Humanos , Imagens de Fantasmas , Rotação
16.
J Orthop Surg Res ; 17(1): 315, 2022 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-35701787

RESUMO

BACKGROUND: Abnormal epiphyseal growth plate development of the proximal tibia in hemophilia patients leads to notable morphological changes in the mature knee joint. This study aimed to compare the morphological characteristics of tibial component placement cut surface in patients with hemophilic arthritis (HA) and osteoarthritis (OA) and to determine the tibial component rotational alignment axis' best position for HA patients. METHODS: Preoperative computed tomography scans of 40 OA and 40 HA patients who underwent total knee arthroplasty were evaluated using a three-dimensional (3D) software. The tibial component's placement morphological parameters were measured. The tibial component's rotational mismatch angles were evaluated, and the most appropriate 0°AP axis position for HA patients was investigated. RESULTS: In the two groups, the morphology was significantly different in some of the parameters (p < 0.05). The tibial component rotational mismatch angles were significantly different between both groups (p < 0.05). The medial 9.26° of the medial 1/3 of the patellar tendon was the point through which 0°AP axis passed for the HA patients. Similarly, the medial 13.02° of the medial 1/3 of the tibial tubercle was also the point through which the 0°AP axis passed. CONCLUSIONS: The ratio of the anteroposterior length to the geometric transverse length of the placement section of the tibial component in HA patients was smaller than that in OA patients. The medial 9.26° of the medial 1/3 of the patellar tendon or the medial 13.02° of the medial 1/3 of the tibial tubercle seem to be an ideal reference position of the rotational alignment axis of the tibial component for HA patients.


Assuntos
Artroplastia do Joelho , Hemofilia A , Osteoartrite do Joelho , Artroplastia do Joelho/métodos , Hemofilia A/complicações , Hemofilia A/diagnóstico por imagem , Humanos , Articulação do Joelho/diagnóstico por imagem , Articulação do Joelho/cirurgia , Osteoartrite do Joelho/diagnóstico por imagem , Osteoartrite do Joelho/etiologia , Osteoartrite do Joelho/cirurgia , Rotação , Tíbia/anatomia & histologia , Tíbia/diagnóstico por imagem , Tíbia/cirurgia
17.
J Orthop Surg Res ; 17(1): 325, 2022 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-35729647

RESUMO

OBJECTIVE: To investigate the biomechanical effects of interbody cage height on adjacent segments in patients with lumbar degeneration undergoing transforaminal lumbar interbody fusion (TLIF) surgery, so as to provide references for selection of interbody cage. METHODS: The finite element model of normal lower lumbar spine (L3-S1) was built and validated, then constructed three different degenerative segments in L3-L4, and the cages with different height (8, 10, 12, 14 mm) were implanted into L4-L5 disc. All the twelve models were loaded with pure moment of 7.5 N m to produce flexion, extension, lateral bending and axial rotation motions on lumbar spine, and the effects of cage height on range of motion (RoM) and intervertebral pressure in lumbar spine were investigated. RESULTS: The RoM of adjacent segments and the maximum stress of intervertebral discs increased with the increase in cage height, but this trend was not obvious in mild and moderate degeneration groups. After implantation of four different height cages (8, 10, 12, 14 mm), the RoM of L3/L4 segment reached the maximum during extension. The RoM of mild degeneration group was 2.07°, 2.45°, 2.48°, 2.54°, that of moderate degeneration group was 1.79°, 1.97°, 2.05°, 2.05°, and that of severe degeneration group was 1.43°, 1.66°, 1.74°, 1.74°. The stress of L3-L4 intervertebral disc reached the maximum during flexion. The maximum stress of L3-L4 intervertebral disc was 20.16 MPa, 20.28 MPa, 20.31 MPa and 20.33 MPa in the mild group, 20.58 MPa, 20.66 MPa, 20.71 MPa and 20.75 MPa in the moderate group, and 21.27 MPa, 21.40 MPa, 21.50 MPa and 21.60 MPa in the severe group. CONCLUSION: For patients with mild-to-moderate lumbar degenerative disease who need to undergo TLIF surgery, it is recommended that the height of fusion cage should not exceed the original intervertebral space height by 2 mm, while for patients with severe degeneration, a fusion cage close to the original intervertebral height should be selected as far as possible, and the intervertebral space should not be overstretched.


Assuntos
Degeneração do Disco Intervertebral , Fusão Vertebral , Fenômenos Biomecânicos , Análise de Elementos Finitos , Humanos , Degeneração do Disco Intervertebral/cirurgia , Vértebras Lombares/cirurgia , Amplitude de Movimento Articular , Rotação
18.
Comput Intell Neurosci ; 2022: 3835649, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35733560

RESUMO

Because of the overwhelming characteristics of computer vision technology, the trend of intelligent upgrading in sports industry is obvious. Video technical and tactical data extraction, big data analysis, and match assistance systems have caused profound changes to all aspects of the sports industry. One of the important applications is the playback and analysis of sports videos. People can observe the videos and summarize the experience of sports matches, and in this process, people prefer the computers to also interpret and analyze sports matches, which can not only help coaches in postmatch analysis but also design robots to assist in teaching and training. In this paper, we have examined and designed an automatic detection system for ping pong balls, in which the motion trajectory and rotation information of ping pong balls are mainly detected. To achieve this goal, the detection and tracking algorithm of ping pong balls based on deep neural network is used, and better results are achieved on the data set established by ourselves and the actual system test. After obtaining the position of the ping pong ball in the image, the rotation direction and speed of the ping pong ball are calculated next, and the Fourier transform-based speed measurement method and the CNN-based rotation direction detection method are implemented, which achieve better results in the testing of lower speed datasets. Finally, this paper proposes an LSTM-based trajectory prediction algorithm to lay the foundation for the design of table tennis robot by predicting the trajectory of table tennis. Experimental tests show that the proposed system can better handle the ping pong ball tracking and rotation measurement problems.


Assuntos
Tênis , Algoritmos , Humanos , Rotação
19.
Clin Biomech (Bristol, Avon) ; 97: 105688, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35661894

RESUMO

BACKGROUND: The objective of the present isolated spine study was to evaluate the kinematic differences between groups of normal and degenerated cervical spine specimens. Previous studies on cervical spine degeneration support the existence of the unstable phase during the degeneration process; however, there is a lack of quantitative data available to fully characterize this early stage of degeneration. METHOD: For this effort five degenerated and eight normal cervical spines (C2-T1) were isolated and were subject to pure bending moments of flexion, extension, axial rotation and lateral bending. The specimen quality was assessed based on the grading scale. In the present study, the degeneration was at the C5-C6 level. A four-camera motion analysis system was used to measure the overall primary and segmental motions. FINDING: In the extension mode, the degenerated group demonstrated a significant larger angular rotation as well as antero-posterior displacement at the degenerated level (C5-C6). In contrast, in flexion mode, the degenerated group measured a drastic decrease in angular rotation, at the adjacent level (C6-C7). In other modes of loading as well as in other segmental levels, the degenerated group had similar segmental motion as the normal group. INTERPRETATION: These preliminary results provide single level degeneration specific cervical spine kinematics. The finding demonstrates the influence of degeneration on the kinematics of the normal sub adjacent segment. The degenerated group observed larger translation displacement in the extension mode, which would potentially be a critical parameter in assisting early detection of cervical spine spondylosis with just a functional X-ray scan.


Assuntos
Vértebras Cervicais , Osteoartrite da Coluna Vertebral , Fenômenos Biomecânicos , Vértebras Cervicais/diagnóstico por imagem , Humanos , Amplitude de Movimento Articular , Rotação
20.
J Manipulative Physiol Ther ; 45(2): 137-143, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35764470

RESUMO

OBJECTIVE: The purpose of this study was to determine the normal range of rotation occurring during rotation stress testing for alar ligament integrity and to ascertain whether rotation range on testing is affected by an individual's age. METHOD: In this observational study, 88 people aged 18 to 86 years old with no current neck problems or known risk factors for craniocervical instability underwent rotation stress testing for the alar ligaments. The test was performed in each direction in neutral, flexion, and extension, with the participant both sitting and supine. Rotation range was recorded using an electromagnetic movement tracking system. Range was assessed overall and then compared by 10-year age groups using analysis of variance. Reliability of measurements was assessed by intraclass correlation coefficient(2,1) and standard error of measurement. RESULTS: Mean angles of upper cervical rotation ranged between 10.91° (standard deviation 3.38°) to 16.12° (standard deviation 5.13°). Overall measured rotation ranged from 1.37° to 33.22°. Participants in older age groups generally displayed reduced rotation; however, the reduction was less than 4°. Reliability of rotation measurements was good to excellent, with the intraclass correlation coefficient ranging from 0.80 to 0.99. CONCLUSIONS: Normal range of rotation measured during stress testing for the alar ligament varied widely but did not exceed 33o. All values measured in this study fell below recommendations for ligament integrity. Age-related change was not clinically significant in the interpretation of this test in this asymptomatic population.


Assuntos
Articulação Atlantoaxial , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Fenômenos Biomecânicos , Humanos , Ligamentos Articulares , Pessoa de Meia-Idade , Amplitude de Movimento Articular , Valores de Referência , Reprodutibilidade dos Testes , Rotação , Adulto Jovem
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