• Journal of Korean Neurosurgical Society
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• v.57 no.2
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• pp.108-113
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• 2015

Objective : Although the L5-S1 has distinct structural features in comparison with other lumbar spine segments, not much is known about adjacent segment degeneration (ASD) at the L5-S1 segment. The aim of study was to compare the incidence and character of ASD of the cephalad and L5-S1 segments after L5 floating lumbar fusion. Methods : From 2005 to 2010, 115 patients who underwent L5 floating lumber fusion were investigated. The mean follow-up period was 46.1 months. The incidence of radiological and clinical ASD of the cephalad and the L5-S1 segments was compared using survival analysis. Risk factors affecting ASD were analyzed using a log rank test and the Cox proportional hazard model. Results : Radiological ASD of the L5-S1 segment had a statistically significant higher survival rate than that of the cephalad segment (p=0.001). However, clinical ASD of the L5-S1 segment was significantly lower survival rates than that of the cephalad segment (p=0.038). Risk factor analysis showed that disc degeneration of the cephalad segment and preoperative spinal stenosis of the L5-S1 segment were risk factors. Conclusion : In L5 floating fusion, radiological ASD was more common in the cephalad segment and clinical ASD was more common in the L5-S1 segment. At the L5-S1 segment, the degree of spinal stenosis appears to be the most influential risk factor in ASD incidences, unlike the cephalad segment.

• Journal of Korean Neurosurgical Society
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• v.45 no.2
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• pp.81-84
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• 2009

Objective : Many biomechanical and clinical studies on adjacent segment degeneration (ASD) have addressed cranial segment. No study has been conducted on caudal segment degeneration after upper segment multiple lumbar fusions. This is a retrospective investigation of the L5-S1 segment after spinal fusion at and above L4-5, which was undertaken to analyze the rate of caudal ASD at L5-S1 after spinal fusion on and above L4-5 and to determine that factors that might have influenced it. Methods : The authors included 67 patients with L4-5, L3-5, or L2-5 posterior fusions. Among these patients, 28 underwent L4-5 fusion, 23 L3-5, and 16 L2-5 fusions. Pre- and postoperative radiographs were analyzed to assess degenerative changes at L5-S1. Also, clinical results after fusion surgery were analyzed. Results : Among the 67 patients, 3 had pseudoarthrosis, and 35 had no evidence of ASD, cranially and caudally. Thirteen patients (19.4%) showed caudal ASD, 23 (34.3%) cranial ASD, and 4 (6.0%) both cranial and caudal ASD. Correlation analysis for caudal ASD at L5-S1 showed that pre-existing L5-S1 degeneration was most strongly correlated. In addition, numbers of fusion segments and age were also found to be correlated. Clinical outcome was not correlated with caudal ASD at L5-S1. Conclusion : If caudal and cranial ASD are considered, the overall occurrence rate of ASD increases to 50%. The incidence rate of caudal ASD at L5-S1 was significantly lower than that of cranial ASD. Furthermore, the occurrence of caudal ASD was found to be significantly correlated with pre-existing disc degeneration.

• Journal of Korean Institute of Industrial Engineers
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• v.25 no.3
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• pp.393-403
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• 1999

In this research, a reach posture prediction based on a two-segment trunk model was made. Recently, reach posture prediction models have used inverse kinematics to provide a single posture that a person naturally takes, with a single segment trunk model that had some shortcomings. A two-segment trunk model was first developed with two links; pelvis link and lumbar-thoracic link. The former refers to the link from the hip joint to L5/S1 joint while the latter does the link from L5/S1 to the shoulder joint. Second, a reach prediction model was developed using the two-segment trunk model. As a result, more reliable equations for two-segment trunk motion were obtained, and the lean direction which refers to the movement direction of the trunk was not found to have a significant effect on the two-segment trunk motion. The results also showed that the hip joint is more preferred over L5/S1 to serve as a reference point for trunk models and the reach prediction model being developed predicted the real posture accurately.

• The Journal of Korean Society of Virology
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• v.29 no.3
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• pp.155-163
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• 1999

Hantaan virus (HTNV), the etiologic agent of hemorrhagic fever with renal syndrome (HFRS), belongs to the genus Hantavirus, and has three single negative stranded RNA genome segments. HTNV strain Howang isolated from the blood of severe case of Korean HFRS is more virulent than HTNV 76/118 and the M and S genome segments' nucleotide sequence of Howang strain showed 93.5% and 94% homology to each segment of HTNV 76/118. We have obtained 6533 nucleotides long sequence of the L genome segment of Howang strain using reverse transcriptase in conjunction with PCR amplification and compared to other hantaviruses. The messenger sense of the L segment contains one long single long open reading frame of 2151 amino acids, which encodes a deduced RNA dependent RNA polymerase of 246.4 kDa caculated molecular weight protein. The nucleotide sequence of the L segment of Howang strain shows 93%, 74%, 66%, 65% homology to HTNV 76/118, Seoul virus 80/39, Puumala virus $H{\ddot{a}}lln{\ddot{a}}s$ B1 and Sin Nombre virus, respectively. The amino acid sequence of the L segment of Howang strain shows 99%, 85%, 68%, 68% homology to HTNV 76/118, Seoul virus 80/39, Puumala virus $H{\ddot{a}}lln{\ddot{a}}s$ B1 and Sin Nombre virus, respectively.

• Journal of Veterinary Clinics
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• v.7 no.1
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• pp.371-380
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• 1990

This experiment was performed to investigate the electrocardiographic changes in experimentally induced hypocalcemia and hypercalcemia in Korean black goats by dosing with 5% disodiumethylene diamine tetraacetic acid at 0.07$m\ell$/kg body weight/min and 10% Ca-borog-luconate at 0.075 $m\ell$/kg body weight/min, respectively. the result were summarized as follows： Heart rate, S-T segment and Q-Tc interval at 3.23 ${\pm}$ 0.10mEq/L plasma calcium level(hypocalcemia) were increased to 100${\pm}$10.5 rate/min, 132 ${\pm}$10msec and 510${\pm}$40msec, respectively. Heart rate, S-T segment and Q-T interval at 6.89${\pm}$0.23mEq/L plasma calcium level(hypercalcemia) were decreased to 73.2${\pm}$5.16 rate/min, 87${\pm}$10msec and 372${\pm}$30msec, respectively. The degree of changes of the heart rate, S-T segment and Q-Tc interval at low plasma calcium level was higher than those at high plasma calcium level.

• The Journal of Churna Manual Medicine for Spine and Nerves
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• v.8 no.1
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• pp.39-47
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• 2013

Objectives : The purpose of this study is to find out the relationship between hip internal rotation angle and the level of herniation of lumbar intervertebral disc(HIVD) in single-segment. Methods : We investigated 314 patients (158 male, 156 female) who were diagnosed as herniation of lumbar intervertebral disc(HIVD) in single-segment. We measured 314 patients' hip internal rotation angle and analysed the relationship between the hip internal rotation angle and the level of herniation of lumbar intervertebral disc(HIVD). Results : 1. Among 314 cases, the hip internal rotation angle was different between male and female. Hip internal rotation angle of male was mainly limited and that of female was mainly excessive. 2. Among 314 cases, the normal group, defined as patients who have specific range of hip internal rotation angle(male : $35^{\circ}{\pm}10^{\circ}$, female : $45^{\circ}{\pm}10^{\circ}$), tends to be occurred HIVD at L4/5 level. The limited group, defined as patients who have less angle than normal group, the excessive group, defined as patients who have more angle than normal group, and the complex group, defined as patients who have more angle of one leg and less angle of the other leg than normal group, tend to be occurred HIVD at L5/S1 level(p<0.05). Conclusions : In single-segment lumbar HIVD patients, The normal hip internal rotation angle mainly leads to L4/5 HIVD, while the limited and excessive hip internal rotation angle mainly lead to L5/S1 HIVD.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.2
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• pp.130-136
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• 2010

For stability analysis of the lumbar spine, the hypothesis presented is that the disc has stress sensors driving feedback mechanism, which could react to the imposed loads by adjusting the contraction of the muscles. Fusion in the motion segment of the lumbar spinal column is believed to alter the stability of the spinal column. To identify this effect finite element (FE) models combined with optimization technique was applied and quantify the role of each muscle and reaction forces in the spinal column with respect to the fusion level. The musculoskeletal FE model was consisted with detailed whole lumbar spine, pelvis, sacrum, coccyx and simplified trunk model. Vertebral body and pelvis were modeled as a rigid body and the rib cage was constructed with rigid truss element for the computational efficiency. Spinal fusion model was applied to L3-L4, L4-L5, L5-S1 (single level) and L3-L5 (two levels) segments. Muscle architecture with 46 local muscles was used as acting directions. Minimization of the nucleus pressure deviation and annulus fiber average axial stress deviation was selected for cost function. As a result, spinal fusion produced reaction changes at each motion segment as well as contribution of each muscle. Longissimus thoracis and psoas major muscle showed dramatic changes for the cases of L5-S1 and L3-L5 level fusion. Muscle force change at each muscle also generated relatively high nucleus pressure not only at the adjacent level but at another level, which can explain disc degeneration pattern observed in clinical study.

• Journal of Korean Neurosurgical Society
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• v.51 no.1
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• pp.20-23
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• 2012

Objective : To compare radiographic analysis on the sagittal lumbar curve when standing, sitting on a chair, and sitting on the floor. Methods : Thirty asymptomatic volunteers without a history of spinal pathology were recruited. The study population comprised 11 women and 19 men with a mean age of 29.8 years. An independent observer assessed whole lumbar lordosis (WL) and segmental lordosis (SL) between L1 and S1 using the Cobb's angle on lateral radiographs of the lumbar spine obtained from normal individuals when standing, sitting on a chair, and sitting on the floor. WL and SL at each segment were compared for each position. Results : WL when sitting on the floor was reduced by 72.9% than the average of that in the standing position. Of the total decrease in WL, 78% occurred between L4 to S1. There were significant decreases in SL at all lumbar spinal levels, except L1-2, when sitting on the floor as compared to when standing and sitting on a chair. Changes in WL between the positions when sitting on a chair and when sitting on the floor were mostly contributed by the loss of SL at the L4-5 and L5-S1 levels. Conclusion : When sitting on the floor, WL is relatively low; this is mostly because of decreasing lordosis at the L4-5 and L5-S1 levels. In the case of lower lumbar fusion, hyperflexion is expected at the adjacent segment when sitting on the floor. To avoid this, sitting with a lordotic lumbar curve is important. Surgeons should remember to create sufficient lordosis when performing lower lumbar fusion surgery in patients with an oriental life style.

• Korean Journal of Computational Design and Engineering
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• v.13 no.1
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• pp.58-66
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• 2008

The artificial discs have recently used to preserve the motion of the treated segment in lumbar spine surgery. However, there have been lack of biomechanical information of the artificial discs to explain current clinical controversies such as long-term results of implant wear and excessive facet contact forces. In this study, we investigated the biomechanical effects of three artificial implants on the lumbar spinal segments by finite element analysis. The finite element model of intact lumbar spine(L1-S) was developed and the three implants were inserted in L4-L5 segment of the spine model. 5 Nm of flexion and extension moments were applied on the superior plate of L1 with 400 N of compressive load. Excessive motions and high facet contact forces at the surgical level were generated in the all three implanted models. In the flexion, the peak von-Mises stresses in the semi-constrained type implant was higher than those in the un-constrained type implant which would cause wear on the polyethylene core. The results of the study would provide a biomechanical guideline for selecting optimal surgical approach or evaluating the current design of the implants, or developing a new implant.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.9
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• pp.1-9
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• 2007

For an efficient implementation of cryptosystems based on arithmetic in a finite field $GF(2^n)$, their hardware implementation is an important research topic. To construct a multiplier with low area complexity, the divide-and-conquer technique such as the original Karatsuba-Ofman method and multi-segment Karatsuba methods is a useful method. Leone proposed an efficient parallel multiplier with low area complexity, and Ernst at al. proposed a multiplier of a multi-segment Karatsuba method. In [1], the authors proposed new $MSK_5$ and $MSK_7$ methods with low area complexity to improve Ernst's method. In [3], the authors proposed a method which combines $MSK_2$ and $MSK_3$. In this paper we propose an efficient multiplication method by combining $MSK_2,\;MSK_3\;and\;MSK_5$ together. The proposed method reduces $116{\cdot}3^l$ gates and $2T_X$ time delay compared with Gather's method at the degree $25{\cdot}2^l-2^l with l>0.