In Vivo Bone Motion From High Frame Rate Stereo Radiography

2003 ◽  
Author(s):  
William J. Anderst ◽  
Scott Tashman
Keyword(s):  
Subchondral Bone ◽  
High Speed ◽  
Imaging System ◽  
Close Contact ◽  
Cruciate Ligament ◽  
Joint Space ◽  
Frame Rate ◽  
Bone Surface ◽  
Post Surgery ◽  
Ct Slices

This paper presents a method to calculate functional joint space during dynamic movement. This method combines high-speed biplane radiographic image data and three-dimensional (3D) bone surface data obtained from computed tomography (CT). Subjects were patients undergoing anterior cruciate ligament (ACL) reconstructive surgery. Three tantalum beads were implanted bilaterally into both the femur and tibia during surgery. CT scans were performed after bead implantation, and the CT slices were reconstructed into 3D solid figures, with the implanted beads identifiable within the stack of CT slices. Subjects were tested 6,12 and 24 months post surgery. Testing activities included downhill running on a treadmill and one-legged hopping onto a force plate. During testing, the stereo-radiographic imaging system collected images at 250 frames per second. Later, the implanted beads were identified in the x-ray images and tracked in 3D with an accuracy of 0.10 mm. The 3D bead location data were used to position the reconstructed solid bone figures in 3D space. In this way, the location of each bone surface was determined each instant. This method can be used to identify the regions of close contact between bones during dynamic motion, to calculate the surface area of subchondral bone within close contact, and to determine the changing position of the close contact area during dynamic activities. Using these techniques, comparisons can be made between subchondral bone motion in healthy and reconstructed joints and changes in dynamic joint space can be measured over time.

Nucleate Boiling From Micro-Machined Surfaces

2003 ◽  
Author(s):  
Adrian M. Holland ◽  
Colin P. Garner
Keyword(s):  
Heat Transfer ◽  
High Speed ◽  
Imaging System ◽  
Laser System ◽  
Ccd Camera ◽  
Nucleate Boiling ◽  
Heat Fluxes ◽  
Frame Rate ◽  
High Speed Imaging ◽  
Machined Surfaces

This paper discusses the production and use of laser-machined surfaces that provide enhanced nucleate boiling and heat transfer characteristics. The surface features of heated plates are known to have a significant effect on nucleate boiling heat transfer and bubble growth dynamics. Nucleate boiling starts from discrete bubbles that form on surface imperfections, such as cavities or scratches. The gas or vapours trapped in these imperfections serve as nuclei for the bubbles. After inception, the bubbles grow to a certain size and depart from the surface. In this work, special heated surfaces were manufactured by laser machining cavities into polished aluminium plates. This was accomplished with a Nd:YAG laser system, which allowed drilling of cavities of a known diameter. The size range of cavities was 20 to 250 micrometers. The resulting nucleate pool boiling was analysed using a novel high-speed imaging system comprising an infrared laser and high resolution CCD camera. This system was operated up to a 2 kHz frame rate and digital image processing allowed bubbles to be analysed statistically in terms of departure diameter, departure frequency, growth rate, shape and velocity. Data was obtained for heat fluxes up to 60 kW.m−2. Bubble measurements were obtained working with water at atmospheric pressure. The surface cavity diameters were selected to control the temperature at which vapour bubbles started to grow on the surface. The selected size and spacing of the cavities was also explored to provide optimal heat transfer.

scholarly journals Kinematics and control of frog hindlimb movements

1991 ◽  
Vol 65 (3) ◽  
pp. 547-562 ◽  
Author(s):  
D. J. Ostry ◽  
A. G. Feldman ◽  
J. R. Flanagan
Keyword(s):  
Nervous System ◽  
High Speed ◽  
Imaging System ◽  
Maximum Velocity ◽  
Joint Space ◽  
Motion Path ◽  
Three Dimension ◽  
Joint Angles ◽  
Joint Configuration ◽  
Straight Line

1. The determinants of the motion path of the hindlimb were explored in both intact and spinal frogs. In the spinal preparations the kinematic properties of withdrawal and crossed-extension reflexes were studied. In the intact frog the kinematics of withdrawal and swimming movements were examined. Frog hindlimb paths were described in joint angle (intrinsic) coordinates rather than limb endpoint (extrinsic) coordinates. 2. To study withdrawal and crossed-extension reflexes, the initial angles at the hip, knee, and ankle were varied. Withdrawal and crossed extension were recorded in three dimension (3-D) with the use of an infra-red spatial imaging system. Swimming movements against currents of different speeds were obtained with high-speed film. 3. Three strategies were considered related to the form of the hypothesized equilibrium paths specified by the nervous system: all trajectories lie on a single line in angular coordinates; all trajectories are directed toward a common final position; and all trajectories have the same direction independent of initial joint configuration. 4. Joint space paths in withdrawal were found to be straight and parallel independent of the initial joint configuration. The hip and knee were found to start simultaneously and in 75% of the conditions tested to reach maximum velocity simultaneously. Hip-knee maximum velocity ratios were similar in magnitude over differences in initial joint angles. This is consistent with the observation of parallel paths and supports the view that the nervous system specifies a single direction for equilibrium trajectories. 5. Straight line paths with slopes similar to those observed in withdrawal in the spinal preparation were found in swimming movements in the intact frog. Straight line paths in joint space are consistent with the idea that swimming and withdrawal are organized and controlled in a joint-level coordinate system. The similarities observed between spinal and intact preparations suggest that a common set of constructive elements underlies these behaviors. 6. Path curvature was introduced when joint limits were approached toward the end of the movement. Depending on the initial joint angles, the joint movements ended at different times. When initial joint angles were unequal, joints moving from smaller initial angles reached their functional limits earlier and stopped first. 7. In withdrawal and crossed extension in the spinal frog, velocity profiles at a given joint were similar over the initial portion of the curve for movements of different amplitude. This is consistent with the idea that withdrawal and crossed-extension movements of different amplitude are produced by a constant rate of shift of the equilibrium position.

Optical Diagnostics of Nucleate Boiling From Transparent Heated Surfaces

2003 ◽  
Author(s):  
Anton Zimmermann ◽  
Adrian M. Holland ◽  
Colin P. Garner
Keyword(s):  
Void Fraction ◽  
Indium Tin Oxide ◽  
High Speed ◽  
Imaging System ◽  
Nucleate Boiling ◽  
Nucleation Site ◽  
Heat Fluxes ◽  
Diagnostic Methods ◽  
Frame Rate ◽  
Site Density

Indium Tin Oxide (ITO) coated glass was used to provide transparent heated surfaces with heat fluxes high enough to generate nucleate boiling in water. The technique enables extended horizontal surfaces exhibiting nucleate boiling to be analysed with novel optical diagnostic methods. A horizontal glass substrate coated with an ITO layer on its top surface was immersed in demineralised water of temperatures between 70 and 80°C. A direct electrical current was passed through the ITO to heat the water. A high-speed imaging system comprising an infrared laser and CCD camera was used to analyse the resulting nucleate pool boiling from the ITO surface. This system was operated at up to 1 kHz frame rate and the bubbles analysed in terms of size and shape. Statistical data regarding bubble size and nucleation site density were obtained for heat fluxes ranging from 63 to 105 kW.m−2. Nucleation site densities were found to be up to 35 000 sites.m−2. Furthermore, non-intrusive cross-sectional void fraction measurements were made, and ranged from zero to 14% of surface area. The increase in both site density and void fraction with increasing heat flux was found to be in good agreement with published literature.

Proteinase-activated Receptor-2 Gene Disruption Limits the Effect of Osteoarthritis on Cartilage in Mice: A Novel Target in Joint Degradation

2011 ◽  
Vol 38 (5) ◽  
pp. 911-920 ◽  
Author(s):  
NATHALIE AMIABLE ◽  
JOHANNE MARTEL-PELLETIER ◽  
BERTRAND LUSSIER ◽  
STEEVE KWAN TAT ◽  
JEAN-PIERRE PELLETIER ◽  
...  
Keyword(s):  
Subchondral Bone ◽  
Structural Changes ◽  
Therapeutic Potential ◽  
Cartilage Damage ◽  
Bone Surface ◽  
Trabecular Thickness ◽  
Post Surgery ◽  
Novel Target ◽  
The Right

Objective.Evidence indicates that proteinase-activated receptor (PAR)-2 participates in the degradative processes of human osteoarthritis (OA). We evaluated the in vivo effect of PAR-2 on articular lesions in a PAR-2-knockout (KO) mouse model of OA.Methods.OA was surgically induced by destabilization of the medial meniscus of the right knee in C57Bl/6 wild-type (WT) and PAR-2 KO mice. Knee swelling was measured throughout the duration of the study (8 weeks postsurgery) and histologic evaluation of cartilage was done to assess structure, cellularity, matrix staining, and remodeling in the deep zone. Morphometric analysis of subchondral bone was also performed.Results.Data showed significant knee swelling in the operated WT mice immediately following surgery, which increased with time (8 weeks post-surgery). Knee swelling was significantly lower (p ≤ 0.0001) in PAR-2 KO mice than in WT mice at both 4 and 8 weeks postsurgery. Cartilage damage was found in both operated WT and PAR-2 KO mice; however, lesions were significantly less severe (global score; p ≤ 0.05) in the PAR-2 KO mice at 4 weeks postsurgery. Operated WT mice showed reduced subchondral bone surface and trabecular thickness with significance reached at 4 weeks (p ≤ 0.03 and p ≤ 0.05, respectively), while PAR-2 KO mice demonstrated a gradual increase in subchondral bone surface with significance reached at 8 weeks (p ≤ 0.007).Conclusion.We demonstrated the in vivo implication of PAR-2 in the development of experimental OA, thus confirming its involvement in OA joint structural changes and reinforcing the therapeutic potential of a PAR-2 antagonist for treatment of OA.

Research on True 3D Imaging System Structure and Voxel Construction

2014 ◽  
Vol 568-570 ◽  
pp. 681-684
Author(s):  
Xin Yu Luo ◽  
Ying Wu Cao ◽  
Yang Yang
Keyword(s):  
High Speed ◽  
3D Imaging ◽  
Imaging System ◽  
State Space Model ◽  
Optical Path ◽  
Frame Rate ◽  
System Structure ◽  
Display Device ◽  
New Approach ◽  
Operating Stability

This paper presents a projection on the basis of the true 3D imaging display system and analyzes construction for the voxel. We proposed a new method based on the theory of high-speed projector - Three DMD/OLED coaxial optical path display. We did some experiments about the clock distribution for the coaxial optical path. The innovation improves frame rate and operating stability for the display device, reduces the high frame rate on one single device. We also found a new approach - local state-space model - Fornasini-Marchesini for constructing the volume pixels. The mechanism is simple to build and low price; the optical field can be displayed in the whole above x-y plane except the zenith point.

scholarly journals Rehabilitation and Return to Sport Assessment after Anterior Cruciate Ligament Injury: Quantifying Joint Kinematics during Complex High-Speed Tasks through Wearable Sensors

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2331
Author(s):  
Stefano Di Paolo ◽  
Nicola Francesco Lopomo ◽  
Francesco Della Villa ◽  
Gabriele Paolini ◽  
Giulio Figari ◽  
...  
Keyword(s):  
Anterior Cruciate Ligament ◽  
Excellent Agreement ◽  
High Speed ◽  
Cruciate Ligament ◽  
Wearable Sensors ◽  
Return To Sport ◽  
Acl Injury ◽  
Wearable Sensor ◽  
Anterior Cruciate ◽  
Full Body

The aim of the present study was to quantify joint kinematics through a wearable sensor system in multidirectional high-speed complex movements used in a protocol for rehabilitation and return to sport assessment after Anterior Cruciate Ligament (ACL) injury, and to validate it against a gold standard optoelectronic marker-based system. Thirty-four healthy athletes were evaluated through a full-body wearable sensor (MTw Awinda, Xsens) and a marker-based optoelectronic (Vicon Nexus, Vicon) system during the execution of three tasks: drop jump, forward sprint, and 90° change of direction. Clinically relevant joint angles of lower limbs and trunk were compared through Pearson’s correlation coefficient (r), and the Coefficient of Multiple Correlation (CMC). An excellent agreement (r > 0.94, CMC > 0.96) was found for knee and hip sagittal plane kinematics in all the movements. A fair-to-excellent agreement was found for frontal (r 0.55–0.96, CMC 0.63–0.96) and transverse (r 0.45–0.84, CMC 0.59–0.90) plane kinematics. Movement complexity slightly affected the agreement between the systems. The system based on wearable sensors showed fair-to-excellent concurrent validity in the evaluation of the specific joint parameters commonly used in rehabilitation and return to sport assessment after ACL injury for complex movements. The ACL professionals could benefit from full-body wearable technology in the on-field rehabilitation of athletes.

scholarly journals SOST Deficiency Aggravates Osteoarthritis in Mice by Promoting Sclerosis of Subchondral Bone

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Jingyu Li ◽  
Junjie Xue ◽  
Yan Jing ◽  
Manyi Wang ◽  
Rui Shu ◽  
...  
Keyword(s):  
Subchondral Bone ◽  
Cruciate Ligament ◽  
Cartilage Degradation ◽  
Cell Number ◽  
Blue Staining ◽  
Sham Operation ◽  
Knee Oa ◽  
Sost Gene ◽  
Bone Sclerosis ◽  
The Difference

As the initial part in the development of osteoarthritis (OA), subchondral bone sclerosis has been considered to be initiated by excess mechanical loading and proven to be correlated to other pathological changes. Sclerostin, which is an essential mechanical stress response protein, is encoded by the SOST gene. It is expressed in osteocytes and mature chondrocytes and has been proven to be closely correlated to OA. However, the relationship and mechanism between the SOST gene and the development of OA remain unclear. The aim of the present study was to investigate the role of the SOST gene in OA pathogenesis in the subchondral bone. A knee anterior cruciate ligament transection (ACLT) mouse osteoarthritis (OA) model on SOST-knockout (SOST KO) and wild-type (WT) mice was established. The pathogenic and phenotypic changes in the subchondral bone were investigated by histology, micro-CT, immunohistochemistry, TRAP staining, Masson staining, and Toluidine blue staining. It was found that sclerostin expression decreased in both the calcified cartilage and mineralized subchondral structures during the development of OA. Joint instability induced a severe cartilage degradation phenotype, with higher OARSI scores in SOST KO mice, when compared to WT mice. SOST KO mice with OA exhibited a higher BMD and BV/TV ratio, as well as a higher rate of bone remodeling and TRAP-positive cell number, when compared to the WT counterparts, but the difference was not significant between the sham-operation groups. It was concluded that loss of sclerostin aggravates knee OA in mice by promoting subchondral bone sclerosis and increasing catabolic activity of cartilage.

scholarly journals On-CMOS Image Sensor Processing for Lane Detection

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3713
Author(s):  
Soyeon Lee ◽  
Bohyeok Jeong ◽  
Keunyeol Park ◽  
Minkyu Song ◽  
Soo Youn Kim
Keyword(s):  
Edge Detection ◽  
High Speed ◽  
Cmos Image Sensor ◽  
Image Sensor ◽  
Image Resolution ◽  
Lane Detection ◽  
Frame Rate ◽  
Total Power ◽  
Detection Accuracy ◽  
Total Power Consumption

This paper presents a CMOS image sensor (CIS) with built-in lane detection computing circuits for automotive applications. We propose on-CIS processing with an edge detection mask used in the readout circuit of the conventional CIS structure for high-speed lane detection. Furthermore, the edge detection mask can detect the edges of slanting lanes to improve accuracy. A prototype of the proposed CIS was fabricated using a 110 nm CIS process. It has an image resolution of 160 (H) × 120 (V) and a frame rate of 113, and it occupies an area of 5900 μm × 5240 μm. A comparison of its lane detection accuracy with that of existing edge detection algorithms shows that it achieves an acceptable accuracy. Moreover, the total power consumption of the proposed CIS is 9.7 mW at pixel, analog, and digital supply voltages of 3.3, 3.3, and 1.5 V, respectively.

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