The origin, functions, and nature of the tributary system in the Chou times

In this dissertation, the author, Ch’un-sik Yi, used the English version of his name, Choon S. Lee

Inter- and Intra-observer Reliability of MRI for Lumbar Lateral Disc Herniation

Background: The authors analyzed inter- and intra-observer agreement with respect to interpretation of simple magnetic resonance T1- and T2-weighted axial and sagittal images for the diagnosis of lumbar lateral disc herniation, including foraminal and extraforaminal disc herniations.Methods: Forty-two patients in whom lumbar lateral disc herniation was suspected or confirmed by simple magnetic resonance imaging at one institute between May 2003 and December 2004 were included. The magnetic resonance images consisting of T1- and T2-weighted axial and sagittal images, and these were reviewed blindly and independently by three orthopaedic spine surgeons in a random manner. The images were interpreted as positive or negative for lateral disc herniation on 2 different occasions 3 months apart. Results were analyzed using Cohens kappa statistic, and strengths of agreements were determined using the Landis and Koch criteria.Results: The kappa values for inter-observer agreement averaged 0.234 (0.282, 0.111, and 0.308 respectively) on the first occasion, and 0.166 (0.249, 0.111, and 0.137 respectively) on the second occasion, with an overall mean value of 0.200. Thus, the strength of agreement was only slight-to-fair according to the Landis and Koch criteria. Kappa values for intra-observer agreement averaged 0.479 (0.488, 0.491, and 0.459 respectively), indicating moderate agreement.Conclusions: The present study indicates that simple magnetic resonance imaging is not a reliable imaging modality for diagnosing lumbar lateral disc herniation. Another imaging study with improved diagnostic values should be developed to diagnose this pathologic finding.Keywords: Lumbar lateral disc herniation, Inter-observer reliability, Intra-observer reliability, Magnetic resonance imagingOAIID:oai:osos.snu.ac.kr:snu2009-01/102/0000004226/1SEQ:1PERF_CD:SNU2009-01EVAL_ITEM_CD:102USER_ID:0000004226EMP_ID:A076317DEPT_CD:801FILENAME:E019T_CiOS-2009_Kim_Inter-and Intra-observer Reliability of MRI for Lumbar.pdfDEPT_NM:의학과EMAIL:[email protected]_YN:NCONFIRM:YCONFIRM:

3-D-Printed dielectric resonator antenna arrays based on standing-wave feeding approach

A novel feeding method for a dielectric resonator array antenna is introduced. Unlike in a corporate feed network, power dividers or quarter-wave transformers are not needed in the new feeding scheme as the design is based on the standing-wave concept. Consequently, the feed network is greatly simplified, and undesired spurious radiation in the feeding network is minimized. The simulated and measured results are in good agreement. A 3-D printer is utilized where the entire array structure is fabricated as a single piece with a dielectric material of polylactic acid. The 3-D printer provides a cost-efficient, simple, and rapid manufacturing process.This work was supported by Comunidad de Madrid under Projects S2018/NMT-4333 MARTINLARA-CM and TEC2016-80386-P.Publicad

Quantum metastability in a class of moving potentials

In this paper we consider quantum metastability in a class of moving potentials introduced by Berry and Klein. Potential in this class has its height and width scaled in a specific way so that it can be transformed into a stationary one. In deriving the non-decay probability of the system, we argue that the appropriate technique to use is the less known method of scattering states. This method is illustrated through two examples, namely, a moving delta-potential and a moving barrier potential. For expanding potentials, one finds that a small but finite non-decay probability persists at large times. Generalization to scaling potentials of arbitrary shape is briefly indicated.Comment: 10 pages, 1 figure

Application of a Cumulative Summation test (CUSUM)in the Lumbar Spine

Study design: Retrospective analysisObjectives: The aim of this study was to monitor the quality control of pedicle screw fixation using a cumulativesummation test (CUSUM).Overview of Literature: CUSUM test has already been used in several different surgical settings including theassessment of outcomes in transplant, laparoscopic, and total hip replacement surgeries. However, there has been nodata regarding CUSUM analysis for spine surgery.Methods: Patients with lumbar spinal stenosis who underwent lumbar fusion surgery were included in this study.The primary outcome was the CUSUM analysis for monitoring the quality control of the accuracy of pedicle screwinsertion.Results: Seven screws of the 100 pedicle screw insertions were considered to have failed in the lumbar fusion surgery,respectively. Throughout the monitoring period, there was no indication by the CUSUM test that the quality ofperformance of the pedicle screw fixation procedure was inadequate.Conclusions: Thisstudy demonstrates the CUSUM test can be a useful tool for monitoring of the quality of proceduresrelated with spine surgery.OAIID:oai:osos.snu.ac.kr:snu2014-01/102/0000004226/7SEQ:7PERF_CD:SNU2014-01EVAL_ITEM_CD:102USER_ID:0000004226ADJUST_YN:NEMP_ID:A079510DEPT_CD:801CITE_RATE:0DEPT_NM:의학과SCOPUS_YN:NCONFIRM:

Fluoroscopically guided anterior atlantoaxial transarticular screws: a feasibility and trajectory study using CT-based simulation software

Background context : Anterior transarticular screw (ATAS) fixation has been suggested as a viable alternative to posterior stabilization. However, we are not aware of previous reports attempting to establish the usefulness of specific fluoroscopic landmark-guided trajectories in the use of ATAS, and we could find no reference to it in a computerized search using MEDLINE. Purpose : To determine the anatomic feasibility of ATAS placement using defined fluoroscopic landmarks to guide screw trajectory. Study design : Evaluation using three-dimensional screw insertion simulation software and 1.0-mm-interval computed tomographic scans. Patient sample : Computed tomographic scans of 100 patients including 50 men and 50 women. Outcome measures : Incidence of violation of the vertebral artery groove of C1 and C2, the spinal canal, and the atlanto-occipital joint and screw lengths and lengths of C1 and C2 purchase. Methods : Four screw trajectories were determined: promontory screw (PS), single central facet (CF) screw, and medial (MF) and lateral (LF) double facet screws. Placement of a 4.0-mm screw was simulated using defined fluoroscopic landmarks for each trajectory. The previously mentioned outcome measures were evaluated and compared for the four trajectories. This study was not supported by any financial sources, and there is no topic-specific potential conflict of interest with this study. Results : No violation of the C1 or C2 vertebral artery groove or of the spinal canal was observed for any of the screw types. Screw lengths and the length of C2 purchase were by far the longest for PS (40.4 +/- 2.8 and 25.7 +/- 2.1 mm, respectively; p < .001 in all post hoc comparisons). The length of C1 purchase was longer for CF (16.4 +/- 2.3 mm) and LF (15.8 +/- 1.6 mm) than PS (14.7 +/- 2.0 mm) and MF (14.6 +/- 2.4 mm) (p <= .001, respectively). There was no atlanto-occipital joint violation if the length of C1 purchase was set at 12 mm for CF and LF and at 10 mm for PS and MF. Conclusions : Our results suggest that it may be possible to place ATASs without violating the vertebral artery groove, spinal canal, or the atlanto-occipital joint by using the described entry points, trajectories, and fluoroscopic landmarks.OAIID:oai:osos.snu.ac.kr:snu2013-01/102/0000004226/16SEQ:16PERF_CD:SNU2013-01EVAL_ITEM_CD:102USER_ID:0000004226ADJUST_YN:YEMP_ID:A079510DEPT_CD:801CITE_RATE:3.355FILENAME:e058t_padua_fluoroscopically guided anterior atlantoaxial transarticular screws.pdfDEPT_NM:의학과EMAIL:[email protected]_YN:YCONFIRM: