Sex Moderates the Relationship between Perceptual-Motor Function and Single-Leg Squatting Mechanics

To examine the isolated and combined effects of sex and perceptual-motor function on single-leg squatting mechanics in males and females. We employed a cross-sectional design in a research laboratory. Fifty-eight females (22.2 ± 3.5 yrs, 1.60 ± .07 m, 64.1 ± 13.0 kg) and 35 males (23.5 ± 5.0 yrs, 1.80 ± .06m, 84.7 ± 15.3 kg) free from time-loss injury in the six months prior, vertigo, and vestibular conditions participated in this study. Independent variables were sex, perceptual-motor metrics (reaction time, efficiency index, conflict discrepancy), and interaction effects. Dependent variables were peak frontal plane angles of knee projection, ipsilateral trunk flexion, and contralateral pelvic drop during single-leg squatting. After accounting for the sex-specific variance and perceptual-motor function effects on frontal plane squatting kinematics, female sex amplified the associations of: higher reaction time, lower efficiency index, and higher conflict discrepancy with greater right ipsilateral peak trunk lean (R2 = .13; p = .05); higher reaction time, lower efficiency index, and higher conflict discrepancy with decreased right contralateral pelvic drop (R2 = .22; p < .001); higher reaction time and lower conflict discrepancy with greater right frontal plane knee projection angle (R2 = .12; p = .03); and higher reaction time with greater left frontal plane knee projection angle (R2 = .22; p < .001). Female sex amplified the relationship between perceptual-motor function and two-dimensional frontal plane squatting kinematics. Future work should determine the extent to which perceptual-motor improvements translate to safer movement strategies.

Manipulating vector solitons with super-sech pulse shapes

Theoretical simulations about manipulating vector solitons with super-sech pulse shapes are conducted based on an optical fiber system in this manuscript. By changing temporal pulses’ parameters when orthogonally polarized pulses have the same or different input central wavelengths, output modes in orthogonal directions will demonstrate different properties. When input orthogonal modes have the same central wavelength, “2+2” pseudo-high-order vector soliton can be generated when time delay is changed. While under the condition of different central wavelengths, orthogonal pulses with multiple peaks accompanied with two wavelengths can be achieved through varying projection angle, time delay or phase difference. Our simulations are helpful to the study of optical soliton dynamics in optical fiber system.

Study of large axial space rebinning algorithm in γ-photon industrial tomography image reconstruction

The accuracy of the existing single slice and Fourier rebinning algorithms depends on the projection angle of the line of response. The increase of such projection angle with the detector size, typical in the large axial space of γ-photon industrial detection, and the loss of some projection data after rebinning, result in the degradation of the image quality. In addition, those algorithms consider the probability of positron annihilation equally distributed along the line of response, which prevents to estimate accurately the positions of the annihilation point, and can originate artifacts and noise in the reconstructed image. In this work, we propose an alternative large axial space rebinning algorithm. In that algorithm, initially the line of response is divided into transverse and axial components. Then, each line of response is uniformly rebinned into all the 2D sinogram data intersecting with it. To improve the accuracy of the estimate of the annihilation point location and suppress the noise effectively, we assign a Gaussian weight coefficient to the projection data, and optimise the rebinning algorithm with it. Finally, we reconstruct the image on the basis of the 2D sinograms with the optimised weights. On the computational side, the algorithm is also accelerated by making use of parallel computing. Both simulation and experimental results show that the proposed method improves the contrast and spatial resolution of 2D reconstructed images. Furthermore, the reconstruction time is not affected by the new method, which is therefore expected to meet the demand of γ-photon industrial inspection imaging.

An adaptive optimal viewing angle determination algorithm for TEVAR operation

Background The determination of the right x-ray angiography viewing angle is an important issue during the treatment of thoracic endovascular aortic repair (TEVAR). An inaccurate projection angle (manually determined today by the physicians according to their personal experience) may affect the placement of the stent and cause vascular occlusion or endoleak. Methods Based on the acquisition of a computed tomography angiography (CTA) image before TEVAR, an adaptive optimization algorithm is proposed to determine the optimal viewing angle of the angiogram automatically. This optimal view aims at avoiding any overlapping between the left common carotid artery and the left subclavian artery. Moreover, the proposed optimal procedure exploits the patient-specific morphology to adaptively reduce the potential foreshortening effect. Results Experimental results conducted on thirty-five patients demonstrate that the optimal angiographic viewing angle based on the proposed method has no significant difference when compared with the expert practice (p = 0.0678). Conclusion We propose a method that utilizes the CTA image acquired before TEVAR to automatically calculate the optimal C-arm angle. This method has the potential to assist surgeons during their interventional procedure by providing a shorter procedure time, less radiation exposure, and less contrast injection.

Seismic facies discrimination incorporating relative rock physics

Seismic facies discrimination is usually performed based on a rock-physics-driven quantitative interpretation approach. The accuracy of the study of rock physics largely impacts the reservoir and fluid recognition. However, the study is commonly conducted with absolute well logs without removing the trend effect. Such an approach may introduce inappropriate low-frequency information and bias further analysis of seismic data (crossplotting, facies probability density function generation, and projection angle determination). By contrast, relative rock physics with the trend decomposed reflects the rock-property variation of the overburden and underlying formation. The relative portions are more consistent with the seismic reflectivity, providing an alternative tool to facies interpretation through a seismic inversion scheme. A workflow for seismic facies discrimination has been investigated that incorporates relative rock physics, long short-term memory-based nonlinear seismic inversion, and Bayesian classification. This workflow is employed in a case study from Songliao Basin in northeast China, through which the results of relative and absolute approaches in key steps are analyzed and compared. The consistency of facies, determined through relative and absolute methods with petrophysical interpretation, is calculated. The relative analysis exhibits improved agreement with petrophysical interpretation in overall facies and reservoir sand discrimination of the blind wells. This indicates the potential to minimize the trend bias by integrating relative rock physics in quantitative interpretation.

Prolonged Load Carriage Impacts Magnitude and Velocity of Knee Adduction Biomechanics

Introduction: Adopting knee adduction biomechanics during prolonged load carriage, a common military occupational activity, may increase service members knee osteoarthritis (OA) risk. Although service members reportedly increase knee adduction motions and moments during prolonged load carriage, it is unknown if either body borne load or walk duration increases velocity of knee adduction biomechanics, and subsequent knee OA risk. Varus thrust and alignment are also related to greater knee OA risk, yet it is unknown whether varus thrust and/or alignment are related to magnitude and velocity of knee adduction biomechanics during prolonged load carriage. Purpose: To determine whether body borne load and walk duration impacted magnitude and velocity of knee adduction biomechanics, or whether increases in knee adduction biomechanics are related to knee varus thrust or alignment. Methods: Seventeen participants (11 male/6 female, 23.2 ± 2.9 yrs, 1.8 ± .09 m, 71.0 ± 12.1 kg) had knee adduction biomechanics quantified while walking 1.3 m/s for 60 minutes with three body borne loads (0 kg, 15 kg, and 30 kg). Specifically, peak, average and maximum velocity, as well as time to peak, for knee adduction angle and moment, and varus thrust (first 16% of stance) were calculated at minutes 0, 30, and 60 of the load carriage task. Static knee alignment was calculated as the frontal plane knee projection angle. Statistical Analysis: Participants were defined as varus thrust (VT, n=8) or control (CON, n=9). Then, each knee adduction measurement was submitted to a repeated measures ANCOVA to test the main effect and interaction between body borne load (0 kg, 15 kg, and 30 kg), time (minutes 0, 30, and 60), and group (VT and CON), with static alignment considered a covariate. Results: A significant 3-way interaction for maximum varus thrust velocity (p=0.014), revealed the VT group exhibited greater maximum velocity at minutes 0 through 60 (p ≤ 0.038) with the 0 kg load, and minutes 0 and 60 (p ≤ 0.043) with the 15 kg load. Significant load by group interactions for magnitude (p=0.008) and average velocity (p=0.013) of varus thrust, and maximum KAA velocity (p=0.041) revealed VT participants exhibited larger and faster varus thrust and knee adduction angle than the CON group with the 0 kg and 15 kg loads (p < 0.050). Additionally, both magnitude and maximum velocity of KAM increased with the addition of load (p=0.009 and p=0.004), and walk duration increased magnitude of varus thrust (p=0.044). Static alignment was not a significant covariate for any knee adduction measure (p > 0.05). Conclusion: During prolonged load carriage participants adopted larger, faster knee adduction biomechanics, potentially increasing risk of knee OA. The VT group exhibited greater knee OA risk, and larger, faster knee adduction motions when walking with the lighter (0 kg and 15 kg) loads; while CON adopted increases in knee adduction biomechanics related to knee OA with the heavy (30 kg) load.

Analysis of Sagittal Thoracic Inlet Measures in Relation to Anterior Access to the Cervicothoracic Junction

Study Design: Retrospective radiographic study. Objective: The aim of this study was to define the association between thoracic inlet measures in relation to anterior access to the cervicothoracic junction. Methods: Trauma CT scans in patients >16 years were analyzed. The projection angle (PA), defined as the angle subtended by a line along the superior endplate of the vertebral body and the line from the anterosuperior corner of the vertebral body to the manubrium, was measured at C7, T1 and T2; angles were positive if the projection was above the manubrium. Thoracic inlet angle (TIA), thoracic inlet distance (TID) and pelvic incidence (PI) were measured. Results: 65 scans were assessed (33 males; mean age 47.7 years (s.d. 8.7)). The mean TIA 79.9° (s.d. 13.4°; range 52.6° – 112.2°), mean TID 66.1 mm (s.d. 6.6 mm) and mean PI was 50.5° (s.d. 10.2°). Mean values for the projection angles at C7, T1 and T2 were 24.2°, 7.6° and −8.3° respectively. PA were positive in 95% at C7, 73% at T1 and 30% at T2. PA at each level correlated significantly with age (mean r=−0.371; P = .015) and TIA (mean r=−0.916; P < .001) but neither TID nor PI. TIA correlated with age (r = 0.328; P = .008). Conclusions: The projection angles of the CTJ vertebrae are influenced by thoracic inlet angle and a lesser degree age. Understanding sagittal spinal parameters in the CTJ can aid in planning surgical strategy and approach.