A 3D-CT Study of the Cortical Bone Trajectory Screw Placement Parameters Based on Lumbar CT.

Objective: The cortical bone trajectory (CBT) technology is an effective substitute for traditional pedicle screw (PS) technology. However, there is still controversy about the CBT screw technology placement strategy. The objective of this study was to simulate cortical screw placement with the help of three-dimensional (3D) software, to discuss the differences in screws between genders and vertebral segments, and to explore a safer and more efficient strategy for cortical screw placement.

Imaging anatomy study related to unilateral biportal endoscopic lumbar spine surgery.

Purpose: To provide lumbar spine anatomical parameters relevant to the UBE technique and explore their intraoperative application.

Methods: CT imaging data processed by Mimics for parametric measurements, including laminar abduction angle (LAA), laminar slope angle (LSA), minimum laminar height (MLH), distance between the inferior margin of the lamina and attachment of the ligamentum flavum onto the cephalad lamina (DLL), distance between the initial point and the middle of the articular process (DIA), and distance from the inferior margin of the lamina to the inferior border of the vertebral body (DLV), and were manually measured.

Results: LAA and DIA gradually increase from L1 to L5.

International comparative study of learning trajectories based on TIMSS 2019 G4 data on cognitive diagnostic models.

Learning trajectory describes the student's learning progress or steps in one area through which teaching and learning can be linked. The cognitive diagnostic model (CDM) is an emerging evaluation theory in education measures. Researchers can determine students' mastery of fine-grained knowledge points by describing the learning trajectory based on CDM.

Effect of L5 spinal canal type on pedicle screw placement based on CT imaging: a retrospective clinical study.

Purpose: The objective of this study was to investigate the optimal entry point and pedicle camber angle for L5 pedicle screws of different canal types.

Methods: CT imaging data were processed by Mimics for simulated pedicle screw placement, and PD (Pedicle diameter), PCA (Pedicle camber angle), LD (Longitudinal distance), TD (Transverse distance), and PBG (Pedicle screw breach grade) were measured. Then they were divided into the Round group and Trefoil group according to the type of spinal canal.

Effects of Pretreatment of the Dorsal Meningovertebral Ligaments on the Incidence of Intraoperative Cerebrospinal Fluid Leakage: A Comparative Study.

Cerebrospinal fluid leakage can lead to postoperative refractory headaches and meningitis. Dural injury is the main cause of postoperative cerebrospinal fluid leakage. Previously, we performed a comprehensive anatomic study on the dorsal meningovertebral ligaments in the lumbosacral regions and concluded that these ligaments are an anatomic factor leading to dural laceration.

A new person-fit method based on machine learning in CDM in education.

Cognitive diagnosis models have become popular in educational assessment and are used to provide more individualized feedback about a student's specific strengths and weaknesses than traditional total scores. However, if the testing data are contaminated by certain biases or aberrant response patterns, such predictions may not be accurate. The current research objective is to develop a new person-fit method that is based on machine learning and improves the functionality of existing person-fit methods.

The Presence of Cartilage Affects Femoral Rotational Alignment in Total Knee Arthroplasty.

Objective: To assess the difference between the posterior condylar angle (PCA) and the mechanical lateral distal femoral angle (mLDFA) in the osseous and cartilaginous contours in a non-arthritic Chinese population.

Methods: Computed tomography (CT) and magnetic resonance imaging (MRI) were obtained from 83 patients with knee injuries before arthroscopy, and femur and distal femoral cartilage three-dimensional (3D) models were constructed. The 3D cartilage model was arranged to share physical space with the 3D femoral model, and then PCA and mLDFA were measured on the osseous and cartilaginous contours, respectively.

International Comparative Study of Statistics Learning Trajectories Based on PISA Data on Cognitive Diagnostic Models.

The cognitive diagnosis model is an emerging evaluation theory. The mastery of fine-grained knowledge points of students can be obtained the cognitive diagnostic model (CDM), which can subsequently describe the learning trajectory. The latter is a description of the learning progress of students in a specific area, through which teaching and learning can be linked.

More Anterior Contact Position in Patients With Fixed-Bearing Unicompartmental Knee Arthroplasty During Daily Activities Than Wear Simulator.

Background: While wear simulation of unicompartmental knee arthroplasty (UKA) showed outstanding long-term wear performance, studies reported that polyethylene (PE) wear was responsible for 12% fixed-bearing (FB) UKA failure. This paper aimed to quantify the 6-degrees-of-freedom (6-DOF) knee kinematics and contact positions of FB UKA during daily activities and compare with the previous results of wear simulator.

Methods: Fourteen patients following unilateral medial FB UKA received a CT scan and dual fluoroscopic imaging during level walking, single-leg deep lunge, and sit-to-stand motion for evaluating 6-DOF FB UKA kinematics.

A Two-Parameter Logistic Extension Model: .

A three-parameter logistic (3PL) model variant, named the two-parameter logistic extension (2PLE) model, was developed. This new model employs a function that integrates item features according to an examinee's ability level instead of a fixed guessing parameter used in the 3PL model to quantify guessing behavior. Correct response probabilities from a solution behavior and guessing behavior increase as the level of ability increases.

A Short Note on Aberrant Responses Bias in Item Response Theory.

Item response models often cannot calculate true individual response probabilities because of the existence of response disturbances (such as guessing and cheating). Many studies on aberrant responses under item response theory (IRT) framework had been conducted. Some of them focused on how to reduce the effect of aberrant responses, and others focused on how to detect aberrant examinees, such as person fit analysis.

Study on the multiple scattering effects of ultrasound contrast agents.

In this paper, the multiple scattering of interacting encapsulated microbubbles in suspensions is calculated using two novel approaches--Kargl's effective medium approach and Ye and Ding's approach of 2nd-order correction. Two types of contrast agents with bubbles of different sizes and concentrations are chosen for our numerical simulations. One is Albunex, which is depicted by Church and has a size range of several microns, and the other is sodium laureate solution (before fractionation) described by Soetanto and Chan and has an average size of 35.

Comparison of EMT and MST approaches in studying linear acoustics in bubbly liquid.

Two kinds of approaches have been used in literature to study the linear acoustics in a liquid-bubble mixture: The effective medium theory approach and the multiple scattering theory approach. Theoretical comparisons of mathematical formulations and intrinsic relations between these two approaches are given in this paper and show their consistency in dealing with the linear acoustics in bubbly liquids. Possible applications of these two methods are also generally discussed.

Study on measurement of dispersive characteristics of higher order mode Lamb waves.

The dispersive characteristics of higher order mode Lamb waves (HOMLW) excited by interdigital transducers (IDT) are measured and analyzed, which are necessary for designing micro-sensor in ultrahigh frequency (UHF). A measurement system is set up, in which dispersive characteristics of HOMLW are obtained by the method of transform between frequency and time domains. The characteristics of amplitude-frequency and phase-frequency of Lamb wave are auto-measured by the system.

Ultrasound attenuation in encapsulated microbubble suspensions: The multiple scattering effects.

The phenomenon of image distortions caused by the multiple scattering (MS) effects of encapsulated microbubbles in ultrasoniqc imaging was experimentally found in previous studies (Soetanto and Chan 2000a), but its mechanism has not been fully understood. To study the MS effects of microbubbles in contrast imaging, two approaches are employed in this article--the effective medium approach initialized by Kargl (2002), which includes all the high-order rescattering of free bubbles, and the classic lowest-order approximation approach of Commander and Prosperetti (1989), which ignores the higher-order rescattering between bubbles. In this work, they are modified to model encapsulated microbubble suspensions, and the discrepancies in attenuation coefficients calculated by these two approaches, i.

The shock formation distance in a bounded sound beam of finite amplitude.

This paper investigates the shock formation distance in a bounded sound beam of finite amplitude by solving the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation using frequency-domain numerical method. Simulation results reveal that, besides the nonlinearity and absorption, the diffraction is another important factor that affects the shock formation of a bounded sound beam. More detailed discussions of the shock formation in a bounded sound beam, such as the waveform of sound pressure and the spatial distribution of shock formation, are also presented and compared for different parameters.