Dual Energy X-ray Absorptiometry를 이용한 소아들의 골밀도에 대한 연구

김선용,신손문,유철우,박용훈 영남대학교 의과대학 1993 Yeungnam University Journal of Medicine Vol.10 No.2

Dual energy x-ray absorptiometry(DEXA)를 이용하여 골밀도에 영향을 줄 인자가 없는 소아 80명을 대상으로 제2-4요추에서 골밀도를 측정하여 연령군과 Tanner stage의 변화에 따른 골밀도의 변화를 연구하고 골밀도와 연령, 체중, 신장, 골연령, 성별, 혈청칼슘, 무기인, 부갑상선호르몬과 Alkaline phosphatase 등과의 상관관계를 알아본 결과, 골밀도는 연령(r=0.696), 체중(r=0.693), 신장(r=0.717), 골연령(r=0.690) 및 Tanner stage(r=0.636) 와 유의한 상관관계가 있었으나(r>0.6) 골대사의 지표인 혈청 칼슘, 무기인, 부갑상선 호르몬 ALP나 성별과는 유의한 상관관계가 없었으며, 특히 남, 여 그리고 전체 환아 각각의 경우에서 연령, 체중, 신장과 골밀도의 직선적 상관관계(남아 : 연령 y=0.4223+0.0289x, 체중 y=0.3879+0.0087x, 신장 y=0.1362+0.0042x 여아 : 연령 y=0.3731+0.0494x, 체중 y=0.3206+0.014x, 신장 y=0.0782+0.0070x 전체 : 연령 y=0.4113+0.0354x, 체중 y=0.3690+0.0107x, 신장 y=0.0628+0.0051x)가 있었다. 연구대상 소아를 4개의 연령군(1군 : 2개월-1세미만, 2군 : 1세이상-5세이하, 3군 : 6세이상-10세이하, 4군 : 11세이상-15세이하)로 나누어 조사한 결과 연령군에 따른 골밀도(g/㎠)의 증가는 1군(BMD:0.335 ±0.175)과 2군(BMD:0.627 ±0.200) 그리고 3군(BMD:0.714 ±0.1896)과 4군(BMD:0.873 ±0.163)에서 유의하게 증가하였으나(p<0.05), 2군과 3군사이에서는 유의한 골밀도의 증가를 관찰할 수 없었으며 남녀간 골밀도의 차이는 없었다(p<0.05). 또한 Tanner stage의 발달에 따라서는 골밀도(g/㎠)는 Tanner stage 1에서는 0.547 ±0.234, Tanner stage 2에서는 0.783 ±0.136, Tanner stage 3에서는 0.998 ±0.080으로서 모든 단계에서 유의하게 증가하였다(p<0.05). 이상의 결과에 의하면 DEXA로 측정한 골밀도는 연령, 체중과 신장 등의 증가와 유의한 상관관계가 있고 이들은 성장 속도가 빠른 연령에서 유의하게 증가하였으며 특히 성적 성숙도의 발달에 따라 유의하게 증가하였다. The bone mineral density(BMD) of the lumbar spine (L2-L4) was measured by using dual energy x-ray absorptiometry(Norland XR26 DEXA) in 80 children aged between 2months and 15years (group 1 : 2month-1years, group 2 : 1year-5years, group 3 ; 6years-10years, group 4 : 11years-15years). The correlation coefficient of BMD with age, body weight, height and Tanner stage were 0.696, 0.693, 0.717 and 0.636 respectively. There were sigificant difference in BMD(g/㎠) between group 1(BMD:0.335 ±0.175) and group 2(BMD:0.627 ±0.200), and group 3(BMD:0.714 ±0.1896) and group 4(BMD:0.873 ±0.163) (p<0.05). There was no significant difference of BMD between boys and girls(p<0.05). BMD also increased significantly with development of Tanner stages(Tanner stage 1 : 0.547 ±0.234, Tanner stage 2 : 0.783 ±0.136, Tanner stage 3 : 0.998 ±0.080) (p<0.05). These data indicate that the BMD was correlated with age, body weight, height and Tanner stage significantly and BMD increased significantly during growth spurt occured in 1 to 4years of age and puberty.

Metrological Atomic Force Microscope Using a Large Range Scanning Dual Stage

김종안,김재완,강추식,엄태봉 한국정밀공학회 2009 International Journal of Precision Engineering and Vol.10 No.5

We developed a metrological atomic force microscope (MAFM) using a large range scanning dual stage and evaluated the performance in the measurement of lateral dimension. AFMs are widely used in nanotechnology for very high spatial resolution, but the limitation in measurement range should be overcome to expand its application in nanometrology. Therefore, we constructed new MAFM having a large measurement of 200 mm × 200 mm by using a dual stage and an AFM head module. The dual stage is composed of a coarse and a fine stage to obtain large scanning range and high resolution simultaneously. Precision surfaces and PTFE sliding pads guide the motion of coarse stage, drove by a fine pitch screw and DC motors. Flexure hinges and PZT actuators are utilized for the fine stage. Multi-axis interferometers measure the five degrees of freedom motion of the dual stage for the position control and the compensation of parasitic angular motions. The vertical displacement of AFM tip is measured by a built-in capacitive sensor in the AFM head module within the range of 38 μm. The performance of the dual stage was evaluated and the expanded uncertainty (k = 2) in the measurements of 1-D displacement L was estimated as [수식] The relative uncertainty in pitch measurement was less than 0.02 % and the improvement of accuracy was verified by comparing with other MAFM, which are mostly due to the expansion of scan range and the compensation of angular motion. To enhance the performance, we will reduce the vibration and examine the motion of stage in the vertical direction during a long range scan.

Dual-time-point FDG PET/CT: Is It Useful for Lymph Node Staging in Patients with Non-Small-Cell Lung Cancer?

Kim, Dae-Weung,Kim, Woo Hyoung,Kim, Chang Guhn The Korea Society of Nuclear Medicine 2012 핵의학 분자영상 Vol.46 No.3

Purpose Dual-time-point (DTP) FDG PET/CT has been shown to be useful for lymph node (LN) staging in patients with non-small-cell lung cancer (NSCLC). The aim of this study was to evaluate the LN staging ability of DTP FDG PET/CT in the predominant area of pulmonary tuberculosis. Methods Sixty-nine NSCLC patients underwent DTP PET/CT. Regions of interest were placed on each LN of each station, and the maximum SUVs were measured. Three variables were obtained: (1) the SUV on the early scan ($SUV_{early}$), (2) the SUV on the delayed scan ($SUV_{delayed}$), and (3) the retention index of the SUV (RI). Each patient had one final LN stage and three other LN stages according to the cutoff values of $SUV_{early}$, $SUV_{delayed}$, and RI. Results In the LN-based analysis, the area under the ROC curve of $SUV_{delayed}$ (0.884) was significantly larger (P< 0.01) than those of $SUV_{early}$ (0.868) and RI (0.717). Among the three variables, $SUV_{delayed}$ was more accurate (P<0.01) for detecting the mediastinal LN metastasis than $SUV_{early}$ and RI. In the patient-based analysis, $SUV_{delayed}$ had correctly determined LN stages in 55 of 69 patients (sensitivity, specificity, and accuracy=88.7 %, 50.0 %, and 79.7 %), whereas $SUV_{early}$ and RI correctly determined LN stages in 53 and 52 patients, respectively. Conclusions In this study, comparing the diagnostic efficacy of $SUV_{early}$, $SUV_{delayed}$, and RI for LN staging in patients with NSCLC, $SUV_{delayed}$ was the most accurate variable for LN staging. DTP PET/CT could provide improved diagnostic accuracy for the LN staging of NSCLC.

Dual Servo Stage Without Mechanical Coupling for Process of Manufacture and Inspection of Flat Panel Displays Via Modular Design Approach

김기현,이문구,최영만,남병욱 한국정밀공학회 2012 International Journal of Precision Engineering and Vol. No.

In micromanufacturing and nanomanufacturing in the semiconductor and flat panel display industry, many kinds of positioning system that have a large working area, high speed, and high accuracy are required. In this paper, the design of a mechanically decoupled dual servo (MDDS) stage is proposed and presented. The stage consists of a coarse stage actuated by a linear motor and a fine stage actuated by a voice coil motor. The two stages are required to be developed independently, if possible, to save lead time and ensure the security of trade secrets; therefore, the MDDS stage is designed according to a modular design approach. A dual servo tracking controller is introduced for the MDDS by appending a fine controller to a conventional coarse controller. Despite the modular design without mechanical coupling, a reaction force between the fine stage and coarse stage is generated by the magnetic coupling that is detrimental to positioning and tracking. Therefore, a simple compensator that reduces the effect of the reaction force is also presented. Simulations and experiments are performed to evaluate the performance of the MDDS stage.

듀얼스테이지를 이용한 밀링머신의 가공특성

양현모,정병묵,고태조,이천,박종권 한국공작기계학회 2009 한국공작기계학회 춘계학술대회논문집 Vol.2009 No.-

High precision machining technology has become one of the important parts in the development of a precision machine. Such a machine requires high speed on a large workspace as well as high precision positioning. For machining systems having a long stroke with ultra precision, a dual-stage system including a global stage (coarse stage) and a micro stage (fine stage) is designed in this paper. Though linear motors have a long stroke and high precision feed drivers, they have some limitations for submicron positioning. Piezo-actuators with high precision also have severe disadvantage for the travel range, and the stroke is limited to a few microns. In the machining experiments, the single stage has an machining error of 2 micron, while the dual stage has only 0.3 micron error. Therefore, this technique can be applied to develop high precision positioning and machining in the micro manufacturing and machining system.

초정밀 듀얼 스테이지를 위한 고댐핑 저진동 제어기 개발

강석일(Seok Il Kang),김정한(Jung-Han Kim) 한국생산제조학회 2016 한국생산제조학회지 Vol.25 No.1

In this study, a cross-damped low vibration controller was developed to reduce vibration in ultra-precision dual stage driven by master/slave principle. In master-slave structure, the master stage leads the driving motion and the slave stage follows it so as to maintain a constant gap between two stages. In this structure, a small perturbation of master stage makes big oscillations in slave servoing stage, so a low damped master stage composed of voice coil motor makes a long vibration in settling area after driving motion profile. In this research, an effective feedback damping algorithm for increase the damping characteristics of the dual stage was developed. The designed velocity damping algorithm improves the system stability and reduces the settling time of the whole system. Simulation and experimental results show that the developed algorithm reduces settling time and improves the regulating performance.

듀얼스테이지를 이용한 밀링머신의 가공특성

양현모(H. M. Yang),정병묵(B. M. Chung),고태조(T. J. Ko),이천(C. Lee),박종권(J. K. Park) 한국생산제조학회 2009 한국생산제조시스템학회 학술발표대회 논문집 Vol.2009 No.5

High precision machining technology has become one of the important parts in the development of a precision machine. Such a machine requires high speed on a large workspace as well as high precision positioning. For machining systems having a long stroke with ultra precision, a dual-stage system including a global stage (coarse stage) and a micro stage (fine stage) is designed in this paper. Though linear motors have a long stroke and high precision feed drivers, they have some limitations for submicron positioning. Piezo-actuators with high precision also have severe disadvantage for the travel range, and the stroke is limited to a few microns. In the machining experiments, the single stage has an machining error of 2 micron, while the dual stage has only 0.3 micron error. Therefore, this technique can be applied to develop high precision positioning and machining in the micro manufacturing and machining system.

Experimental and numerical investigation of non-reaction flow characteristics in a concentric staged dual-swirl combustor

Le Li,Pengfei Zhu,Qiandong Li,Jianqin Suo,Longxi Zheng 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.4

In order to deeply understand the complex swirling flow characteristics of the typical staged and zoned combustor, particle image velocimetry measurement and large eddy simulation were used to study the steady and instantaneous flow field. The results show that an obviously central recirculation zone (CTRZ) cannot be formed by the single pilot stage swirler. When a main stage swirler with strong swirling flow is added, a large CTRZ appears in the concentric staged dual-swirl combustor. The CTRZ size in the co-rotating combustor is obviously larger than that in the counter-rotating combustor. The development process of the CTRZ is divided into three stages: P, P-M and M. The stages P and M are mainly dominated by the pilot stage and main stage swirling air, respectively. In addition, it can be seen from the instantaneous flow field that there is a single spiral precessing vortex core in the co-rotating and counter-rotating combustor.

Robust Minimum-Time Control with Coarse/Fine Dual-Stage Mechanism

SangJoo Kwon,Joono Cheong 대한기계학회 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.11

A robust minimum-time control (RMTC) strategy is addressed and it is extended to the dual-stage servo design. Rather than conventional switching type sub-optimal controls, it is a reference following control approach where the predetermined minimum-time trajectory (MTT) is tracked by the perturbation compensator based feedback controller. First, the minimum-time trajectory for a mass-damper system is derived. Then, the perturbation compensator to achieve robust tracking performance in spite of model uncertainty and external disturbance is suggested. The RMTC is also applied to the dual-stage positioner which consists of coarse actuator and fine one. To best utilize the actuation redundancy of the dual-stage mechanism, a null-motion controller to actively regulate the relative motion between the two stages is formulated. The performance of RMTC is validated through simulation and experiment.

Two Emergent Models in Grief

Pan, Shinhwan 한국실천신학회 2011 신학과 실천 Vol.0 No.29

The popular and traditional models in grief are the stage model. Bowlby's and Kubler-Ross's stage models are analyzed. His model consists of four phases in mourning including numbing, yearning and searching for the lost figure, disorganization and despai, and reorganization. Her model is composed of five stages: denial and isolation, anger, bargaining, depression, and acceptance. The stage models are criticized. They assume that grief is the emotionally linear process. They overemphasize universality and simplicity with ignoring individual differences or multiplicity. They view the griever as a passive victim, and consider the attachment to those who died as dysfunction. They do not recognize the influence of the griever's personality, family, society, and culture upon grief. Overcoming the challenges, there emerge Martin and Doka's model of grieving styles and Stroebe and Schut's dual process model. Martin and Doka's model is consisted of grieving styles and adaptive strategies. In their model, there are four grieving styles such as intuitive, instrumental, blended, and dissonant grieving styles. And there are four strategies that an individual employs in managing her or his grieving styles. They are cognitive, affective, behavioral, and spiritual strategies. Stroebe and Schut's dual process model identifies stressors and adaptive coping process in grief. It specifies the two types of stressors in grief such as loss-oriented and restoration-oriented. And it shows that the functional coping process is composed of fluid fluctuation between confrontation and avoidance. Based on the two emergent models in grief, three guidelines are formulated in the Korean pastoral care of the grievers. First, the intuitive grieving style or grief work is respected and promoted. Second, both loss-and restoration-oriented care are encouraged and implemented. Third, free fluctuation between confrontation and avoidance and open oscillation between loss- and restoration-oriented are accepted and supported.