scholarly journals Influence of Foot Position on the Measurement of First Metatarsal Pronation Using the First Metatarsal Axial Radiographs

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0041
Author(s):  
Aya Sadamasu ◽  
Satoshi Yamaguchi ◽  
Ryosuke Nakagawa
Keyword(s):  
Three Dimensional ◽  
Ct Images ◽  
Virtual Space ◽  
Simple Method ◽  
First Metatarsal ◽  
Digitally Reconstructed Radiographs ◽  
Axial Radiograph ◽  
The Difference ◽  
Foot Position ◽  
Foot Alignment

Category: Other Introduction/Purpose: In hallux valgus (HV) surgery, the importance of correcting first metatarsal (1MT) pronation, as well as correcting adduction, has been increasingly recognized. A 1MT axial radiograph is a simple method to quantify 1MT pronation (see figure). However, this view does not provide the exact axial projection, and 1MT is angled on the image. Furthermore, the 1MT angle is dependent on the foot position and alignment. Therefore the measured pronation angle on the radiograph may not be the same as the “true” pronation along the 1MT long axis. The purposes of this study were to 1) quantify the difference between the measured 1MT pronation on the axial radiograph and the true pronation angle, and 2) determine the influence of foot position on the measurement. Methods: CT images of 10 feet from HV patients (HV group; age, 58 years; HV angle, 44°) and 10 feet from those without HV (non-HV group; age, 47years; HV angle, 12°) were obtained. Digitally reconstructed radiographs of the 1MT were generated from the CT images in a three-dimensional virtual space (see figure). 1MT was pronated along the long axis (true pronation angle). Then, images with different plantarflexion (25° to 35° in 5° increments) and adduction (-10° to 10°) angles were created. This procedure was repeated for different pronation angles (-10° to 30°), and 135 simulated 1MT axial radiographs were obtained from each bone. We measured the 1MT pronation angles in all images. Differences in the measured pronation angle and true pronation angle were calculated for each group. Correlations between the measurement difference and 1MT plantarflexion/adduction angles were assessed using the Spearman correlation coefficient. Results: The mean measurement differences were 0.7° and 1.0° for the HV group and non-HV group, respectively. The standard errors of the measurement were 0.5° and 0.6° for the HV group and non-HV group, respectively. There was no significant correlation between the measurement difference and plantarflexion angle (P = 0.92 and P = 0.92 for the HV group and non-HV group, respectively), nor between the measurement difference and adduction angle (P = 0.82 and P = 0.74). Conclusion: The measurement differences were low in both HV and non-HV feet, indicating that the 1MT pronation angle measured on the axial radiograph represented the true pronation angle along the long axis of 1MT. The measurement differences were consistent regardless of plantarflexion and adduction angles. Therefore, a variation of 1MT angle on the image, which can be caused by the misalignment of foot position while taking the radiograph and difference in foot alignment (such as flatfeet and cavus feet), did not affect the measurement. 1MT axial radiograph could be used as a valid and robust method to quantify 1MT pronation.

Slip Fascia Stiffness Effect to the Fifth Metatarsal Movement during Inversion Landing

2011 ◽  
Vol 189-193 ◽  
pp. 472-475
Author(s):  
Yao Dong Gu ◽  
Xue Jun Ren ◽  
Zhi Yong Li ◽  
Guo Qing Ruan ◽  
Li Yang
Keyword(s):  
Finite Element ◽  
Young’S Modulus ◽  
Three Dimensional ◽  
Vertical Displacement ◽  
Sensitivity Study ◽  
Ct Images ◽  
Head Part ◽  
Fe Model ◽  
3D Finite Element ◽  
The Difference

Injuries of the base of the fifth metatarsal are among the most common of all skeletal injuries of the foot. The fracture is considered by previous research to be an avulsion due to the slip fascia, however, the mechanism of the plantar slip fascia’s function still not very clear. In this study, a detailed three-dimensional (3D) finite element (FE) model was developed by reconstruction of CT images. A sensitivity study was conducted to evaluate the effect of varying stiffness of the slip fascia on the fifth metatarsal’s deformation. The results showed that the largest vertical displacement was appeared in the metatarsal’s head part, and the difference was up to 10.5%, while the Young’s modulus of the slip fascia increasing from 50MPa to 500MPa.

A MORPHOLOGICAL STUDY OF THE SCAPHOID USING A MATHEMATICAL TECHNIQUE AND COMPARATIVE STUDY OF THE THREE-DIMENSIONAL MEASUREMENTS OF THE SCAPHOID

Hand Surgery ◽  
2003 ◽  
Vol 08 (02) ◽  
pp. 157-161 ◽  
Author(s):  
Shoji Fukuda ◽  
Osamu Ishida ◽  
Mitsuo Kido ◽  
Fumihiro Suzumura ◽  
Yoshikazu Ikuta
Keyword(s):  
Wrist Joint ◽  
Regression Line ◽  
Three Dimensional ◽  
Major Axis ◽  
Ct Images ◽  
3D Ct ◽  
Non Union ◽  
Before And After ◽  
Dimensional Measurements ◽  
The Difference

To guide reconstruction of scaphoid non-union, we attempted to create full-scale models of the scaphoid by three-dimensional computed tomography (3D CT) of the healthy side. In this study, we obtained 3D scans of 51 cadaveric hands and studied the difference in morphology between genders and between the left and right sides. The major axis length on a fixed plane and Fourier transformation curve were examined. Ten scaphoid images were also obtained with 3D CT before and after removal from the cadaveric hands. Our findings suggest good correlation between models produced using 3D CT images of the scaphoid alone, and this could serve as an accurate model if the magnification is corrected using the regression line. However, the model using 3D CT images of the intact wrist joint has a large margin of error and its use will not be practical.

Defocus ramp correction in spot-scan imaging

1992 ◽  
Vol 50 (1) ◽  
pp. 130-131
Author(s):  
Kenneth H. Downing
Keyword(s):  
Computer Control ◽  
Three Dimensional ◽  
Sufficient Accuracy ◽  
Objective Lens ◽  
Electron Crystallography ◽  
Contrast Transfer Function ◽  
Tilt Axis ◽  
Specimen Height ◽  
The Difference ◽  
Envelope Functions

Three-dimensional structures of a number of samples have been determined by electron crystallography. The procedures used in this work include recording images of fairly large areas of a specimen at high tilt angles. There is then a large defocus ramp across the image, and parts of the image are far out of focus. In the regions where the defocus is large, the contrast transfer function (CTF) varies rapidly across the image, especially at high resolution. Not only is the CTF then difficult to determine with sufficient accuracy to correct properly, but the image contrast is reduced by envelope functions which tend toward a low value at high defocus.We have combined computer control of the electron microscope with spot-scan imaging in order to eliminate most of the defocus ramp and its effects in the images of tilted specimens. In recording the spot-scan image, the beam is scanned along rows that are parallel to the tilt axis, so that along each row of spots the focus is constant. Between scan rows, the objective lens current is changed to correct for the difference in specimen height from one scan to the next.

scholarly journals Fabrication of Eutectic Ga-In Nanowire Arrays Based on Plateau–Rayleigh Instability

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4616
Author(s):  
Takashi Ikuno ◽  
Zen Somei
Keyword(s):  
Integrated Circuits ◽  
Substrate Surface ◽  
Three Dimensional ◽  
Average Diameter ◽  
Nanowire Arrays ◽  
Scanning Probe ◽  
Rayleigh Instability ◽  
Simple Method ◽  
Flat Substrate ◽  
Metal Nanowire

We have developed a simple method of fabricating liquid metal nanowire (NW) arrays of eutectic GaIn (EGaIn). When an EGaIn droplet anchored on a flat substrate is pulled perpendicular to the substrate surface at room temperature, an hourglass shaped EGaIn is formed. At the neck of the shape, based on the Plateau–Rayleigh instability, the EGaIn bridge with periodically varying thicknesses is formed. Finally, the bridge is broken down by additional pulling. Then, EGaIn NW is formed at the surface of the breakpoint. In addition, EGaIn NW arrays are found to be fabricated by pulling multiple EGaIn droplets on a substrate simultaneously. The average diameter of the obtained NW was approximately 0.6 μm and the length of the NW depended on the amount of droplet anchored on the substrate. The EGaIn NWs fabricated in this study may be used for three-dimensional wiring for integrated circuits, the tips of scanning probe microscopes, and field electron emission arrays.

The iron content of iron superoxide dismutase: determination by anomalous scattering

1983 ◽  
Vol 218 (1210) ◽  
pp. 119-126 ◽  
Keyword(s):  
Superoxide Dismutase ◽  
Iron Content ◽  
Three Dimensional ◽  
Anomalous Scattering ◽  
Total Iron Content ◽  
Iron Site ◽  
Iron Superoxide Dismutase ◽  
Density Map ◽  
The Difference ◽  
Electron Density Map

The number of iron atoms in the dimeric iron-containing superoxide dismutase from Pseudomonas ovalis and their atomic positions have been determined directly from anomalous scattering measurements on crystals of the native enzyme. To resolve the long-standing question of the total amount of iron per molecule for this class of dismutase, the occupancy of each site was refined against the measured Bijvoet differences. The enzyme is a symmetrical dimer with one iron site in each subunit. The iron position is 9 ņ from the intersubunit interface. The total iron content of the dimer is 1.2±0.2 moles per mole of protein. This is divided between the subunits in the ratio 0.65:0.55; the difference between them is probably not significant. Since each subunit contains, on average, slightly more than half an iron atom we conclude that the normal state of this enzyme is two iron atoms per dimer but that some of the metal is lost during purification of the protein. Although the crystals are obviously a mixture of holo- and apo-enzymes, the 2.9 Å electron density map is uniformly clean, even at the iron site. We conclude that the three-dimensional structures of the iron-bound enzyme and the apoenzyme are identical.

scholarly journals Two-Dimensional Visualization of the Three-Dimensional Planned Sacroiliac Screw Corridor with the Slice Fusion Method

2021 ◽  
Vol 10 (2) ◽  
pp. 184
Author(s):  
Maximilian Kerschbaum ◽  
Siegmund Lang ◽  
Florian Baumann ◽  
Volker Alt ◽  
Michael Worlicek
Keyword(s):  
Pelvic Ring ◽  
Three Dimensional ◽  
Fusion Method ◽  
Two Dimensional ◽  
Posterior Pelvic Ring ◽  
Simple Method ◽  
Sacroiliac Screw ◽  
Screw Insertion ◽  
Multiplanar Reconstructions ◽  
Screw Position

Insertion of sacro-iliac (SI) screws for stabilization of the posterior pelvic ring without intraoperative navigation or three-dimensional imaging can be challenging. The aim of this study was to develop a simple method to visualize the ideal SI screw corridor, on lateral two-dimensional images, corresponding to the lateral fluoroscopic view, used intraoperatively while screw insertion, to prevent neurovascular injury. We used multiplanar reconstructions of pre- and postoperative computed tomography scans (CT) to determine the position of the SI corridor. Then, we processed the dataset into a lateral two-dimensional slice fusion image (SFI) matching head and tip of the screw. Comparison of the preoperative SFI planning and the screw position in the postoperative SFI showed reproducible results. In conclusion, the slice fusion method is a simple technique for translation of three-dimensional planned SI screw positioning into a two-dimensional strict lateral fluoroscopic-like view.

scholarly journals Fish bone-derived interconnected carbon nanofibers for efficient and lightweight microwave absorption

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Yangyang Gu ◽  
Peng Dai ◽  
Wen Zhang ◽  
Zhanwen Su
Keyword(s):  
Microwave Absorption ◽  
Carbon Nanofibers ◽  
Three Dimensional ◽  
Fish Bone ◽  
Absorption Properties ◽  
Simple Method ◽  
Microwave Absorption Properties ◽  
Absorption Performance ◽  
Microwave Absorption Performance ◽  
Better Than

AbstractIn this work, we demonstrated a simple method for preparing three-dimensional interconnected carbon nanofibers (ICNF) derived from fish bone as an efficient and lightweight microwave absorber. The as-obtained ICNF exhibits excellent microwave absorption performance with a maximum reflection loss of –59.2 dB at the filler content of 15 wt%. In addition, the effective absorption bandwidth can reach 4.96 GHz at the thickness of 2 mm. The outstanding microwave absorption properties can be mainly ascribed to its well-defined interconnected nanofibers architecture and the doping of nitrogen atoms, which are also better than most of the reported carbon-based absorbents. This work paves an attractive way for the design and fabrication of highly efficient and lightweight electromagnetic wave absorbers.

Kinematic Analysis of Olympic Hurdle Performance: Women's 100 Meters

1985 ◽  
Vol 1 (2) ◽  
pp. 163-173 ◽  
Author(s):  
Ralph Mann ◽  
John Herman
Keyword(s):  
Elite Athlete ◽  
Olympic Games ◽  
Lower Leg ◽  
The Body ◽  
Performance Variables ◽  
Body Velocity ◽  
The Difference ◽  
Foot Position ◽  
Support Time ◽  
Leg Position

Selected kinematic variables in the performance of the Gold and Silver medalists and the eighth-place finisher in the women's 100-meter hurdles final at the 1984 Summer Olympic Games were investigated. Cinematographic records were obtained for all track hurdling events at the Games, with the 100-meter hurdle performers singled out for initial analysis. In this race, sagittal view filming records (100 fps) were collected at the 9th hurdle of the performance. Computer generated analysis variables included both direct performance variables (body velocity, support time, etc.) and body kinematics (upper leg position, lower leg velocity, etc.) that have previously been utilized in the analysis of elite athlete hurdlers. The difference in place finish was related to the performance variables body horizontal velocity (direct), vertical velocity (indirect), and support time (indirect). The critical body kinematics variables related to success included upper and lower leg velocity during support into and off the hurdle (direct), relative horizontal foot position (to the body) at touchdown into and off the hurdle (indirect), and relative horizontal foot velocity (to the body) at touchdown into the hurdle.

scholarly journals SPECTRAL CORRELATIONS IN DISORDERED MESOSCOPIC METALS AND THEIR RELEVANCE FOR PERSISTENT CURRENTS

1996 ◽  
Vol 10 (28) ◽  
pp. 1397-1406 ◽  
Author(s):  
AXEL VÖLKER ◽  
PETER KOPIETZ
Keyword(s):  
Energy Levels ◽  
Three Dimensional ◽  
Average Density ◽  
Electron Interaction ◽  
Energy Window ◽  
Persistent Currents ◽  
Dependent Part ◽  
The Difference ◽  
Aharonov Bohm ◽  
Grand Canonical

We use the Lanczos method to calculate the variance σ2(E, ϕ) of the number of energy levels in an energy window of width E below the Fermi energy for noninteracting disordered electrons on a thin three-dimensional ring threaded by an Aharonov–Bohm flux ϕ. We confirm numerically that for small E the flux-dependent part of σ2(E, ϕ) is well described by the Altshuler–Shklovskii-diagram involving two Cooperons. However, in the absence of electron–electron interactions this result cannot be extrapolated to energies E where the energy-dependence of the average density of states becomes significant. We discuss consequences for persistent currents and argue that for the calculation of the difference between the canonical- and grand canonical current it is crucial to take the electron–electron interaction into account.

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