Sarcopenia and Back Muscle Degeneration as Risk Factors for Back Pain: A Comparative Study

김환정,김갑중,Song Dae Geon,Lee Jong Shin,Park Kun Young,Lee Jae Won,Chang Shann Haw,최원식 대한척추외과학회 2020 Asian Spine Journal Vol.14 No.3

Study Design: Case-control study.Purpose: To investigate the independent associations of back pain with sarcopenia and with back muscle degeneration, and to introduce a new risk index for back muscle degeneration.Overview of Literature: The Asian Working Group for Sarcopenia recommends diagnosis using handgrip strength, gait speed, and skeletal muscle mass. However, these criteria do not strongly reflect back muscle degeneration.Methods: Patients who completed a questionnaire on back-pain between October 2016 and October 2017 were enrolled in this study. Appendicular skeletal muscle index (ASMI), cross-sectional area (CSA) index, fatty infiltration (FI) rate of the paraspinal muscles, and lumbar extensor strength index (LESI) were measured and compared between no back-pain and back-pain group. Correlations between LESI and ASMI, CSA index, and FI rate were analyzed. The back-pain group was further divided according to ASMI into sarcopenia and non-sarcopenia subgroups and by our newly developed back muscle degeneration risk index based on correlation coefficients between LESI and CSA index, FI rate. Differences in ASMI, CSA index, FI rate, LESI, and Visual Analog Scale (VAS) score between subgroups were analyzed.Results: The ASMI, CSA index, FI rate, and LESI differed significantly between back-pain and pain-free groups. The LESI demonstrated the strongest correlation with FI rate. There were no significant differences in VAS score and back muscle degeneration index in the back-pain group when divided according to the presence of sarcopenia. However, there was a significant difference in VAS score between back-pain patients when classified according to high and low back muscle degeneration risk index.Conclusions: We suggest that the degree of back pain is more strongly associated with back muscle degeneration than with sarcopenia. This back muscle degeneration risk index, reflecting both back muscle morphology and function, could be a useful parameter for evaluation of back pain and muscle degeneration.

Phase-canceled backing structure for lightweight ultrasonic transducer

Ji, Seon Mi,Sung, Jin Ho,Park, Chan Yuk,Jeong, Jong Seob Elsevier 2017 Sensors and actuators. A Physical Vol.260 No.-

<P><B>Abstract</B></P> <P>The overall weight of a medical ultrasonic transducer mainly depends on the weight of the backing layer. Therefore, a reduction of the thickness and the weight of the backing layer can be very useful for various types of array transducers whereby the user suffers from the inconvenience of the heavy weight. However, the backing layer with reduced thickness can cause distortions of the transmitted and received signals due to severe ripples reflected from the back-wall of the backing layer. In this study, a novel backing structure is proposed to solve this problem. The suggested backing layer is composed of multiple backing materials with different acoustic impedances to cancel the phases of the reflected signals. The rearmost material can dissipate the residual energy through the absorption effect. To verify these effects, a finite-element-method (FEM) simulation was conducted, and 4.5MHz single-element transducers were fabricated. Although the thickness of the suggested backing layer was reduced by 1/5 compared with the conventional thick bulk-type backing layer, the ripples caused from the backing layer were successfully minimized. Therefore, the proposed backing structure can be a potential way to reduce the thickness of the backing layer resulting in a lightweight ultrasonic transducer.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel backing structure for a lightweight ultrasonic transducer is presented. </LI> <LI> The proposed backing structure can cancel the phases of the echo signals generated in the backing block. </LI> <LI> The performance was evaluated by FEM simulations and experimental measurements using the prototype transducers. </LI> </UL> </P>

요통에 대한 고찰

유재희 京畿專門大學 1999 京畿專門大學 論文集 Vol.- No.27

Low back pain is increasing, because of lack of exercise, bad posture and stress in modern society. The following article is a literature review of low back pan. The purpose of this paper to furnish basic information about lower back pain so that better planning may be given to comprehensive rehabilatation nursing programs. The demographics of low back pain : patients are usually in their twenties to fifties with the highest concentration of patients in their forties. The rate of men and women is almost same. Complaints for low back pain occurs most frequent in the following occupations : nurses(39∼64%) and housekeepers(39∼51%). Types of activities, occupational characteristics and psychological issues all contribute to chronic low back pain. More over age, bad posture, smoking and obesity will also have an influence on low back pain. The most frequent cause for low back pain is a sprained back. Many studies have shown that 4∼10 weeks of exercise will have the fellowing benefits : pain relief, muscle strengthening and an increase in physical and psychological function. Patient with low back pain often have psychological problems such as depression and anxiety. These problems is turn contribute to low back pain. In developed countries, back school programs are managed well. In our country we need to exert ourselves to improve our back school programs recommend creating education programs and exercise programs. These programs will ease as well as prevent low back pain.

불연속체 해석을 이용한 Back-to-Back 보강토 옹벽의 파괴 메커니즘에 관한 연구

유충식(Yoo Chung-Sik),우승제(Woo Seung-Je),전훈민(Jeon Hun-Min),신부남(Shin Bu-Nam) 한국토목섬유학회 2011 한국지반신소재학회 논문집 Vol.10 No.2

본 논문에서는 Back-to-Back(BTB) 보강토 옹벽의 파괴메커니즘에 관한 연구내용을 다루었다. 이를 위해 모형실험과 불연속체 해석(Discrete Element Method, DEM)을 도입한 수치해석을 수행하였다. 먼저 축소모형실험에서는 일반적으로 시공되는 Back-to-Back 보강토 옹벽을 1/10로 축소하여 1-g 모델을 구축한 후 자중만으로 파괴에 도달하도록 하였으며 보강재의 길이변화에 따른 파괴 메커니즘을 고찰하였다. 아울러 모형실험 결과를 토대로 검증된 DEM 해석모델을 이용하여 다양한 시공조건에 대한 해석을 수행하여 BTB 옹벽의 폭 및 보강재 길이에 따른 파괴 메커니즘을 고찰하고 그 결과를 현재 적용되는 FHWA 설계기준과 비교하였다. This paper presents the results of an investigation on the failure mechanism of geosynthetic reinforced soil walls in back-to-back configuration using 1-g reduced-scale model tests as well as discrete element method-based numerical investigation. In the 1-g reduced scale model tests, 1/10 scale back-to-back walls were constructed so that the wall can be brought to failure by its own weight and the effect of reinforcement length on the failure mechanism was investigated. In addition, a validated discrete element method-based numerical model was used to further investigate the failure mechanism of back-to-back walls with different boundary conditions. The results were then compared with the failure mechanisms defined in the FHWA design guideline.

코어운동장비 기반의 요부강화 운동프로그램이 만성요통 노인의 요부근력에 미치는 효과

이상욱(Lee, Sang-Wook),김공(Kim, Kong),이중철(Lee, Jung-Chul),조지훈(Cho, Ji-Hoon),홍지영(Hong, Jee-Young),공현중(Kong, Hyoun-Joong) 한국체육과학회 2015 한국체육과학회지 Vol.24 No.6

This study was conducted to investigate the effect of back strengthening exercise program using core exercise equipment on the back muscles strength in elderly patients with chronic lower back pain. The subjects of this study were 40 elderly people with chronic back pain who are 70 years or older using Seniors Welfare Centers located in Seoul city and suffer from back and lower limb pains that interrupt daily activities. The change in peak torque of adduction and abduction of back extensor, hip and pelvic was measured after a 12-weeks back strengthening exercise program using core exercise equipment. The back strength showed statistically significant difference by measurement point (105°, 120°), between groups (105°, 120°, 135°, 150°, 165°)and by interaction effect (105°, 120°) at each angle (p<.05). The muscle strength of hip also showed significant difference based on interaction effect (p<.05) and the change of strength during abduction and adduction showed significant interaction effect between the measurement points and groups (p<.05). This study applied the exercise program to the range of motion of pelvic and hip, which is greater than that of those in the back. It extended back exercise treatment to the pelvic and hip muscles, which showed positive effect on chronic lower back pain. As such, the effect of back strengthening exercise program using core exercise equipment would be used to wider area of rehabilitation program of chronic lower back pain with expected positive outcome.

우회상장 규제강화가 회계정보의 신뢰성에 미치는 영향 : 코스닥시장을 중심으로

류시영(Sie-Young You),조현우(Hyun-Woo Cho),천종환(Jong-Hwan Chon) 한국국제회계학회 2009 국제회계연구 Vol.0 No.25

This research analyzed the effects of back-door listing regulation intensity on the reliability of accounting information. Back-door listing, which refers to the act of non-listed company to enter stock market in methods of merge with listed company etc instead of via normal IPO, has become rapidly widespread as to take up 46.8% in M&A market during short period of only 4 years while the term itself came into use in late 2003 for the first time. Though it has positive function, restructuring of insolvent listed companies in the market, back-door listing comprehends negative functions like cause of ordinary loss and capital erosion etc, and the results of 'checking the conditions of back-door listing' performed by Financial Services Commission showed that back-door listing aggravates risk through merge between insolvent companies and deteriorates sound M&A. In this according, Financial Services Commission finally came to conduct back-door listing regulation intensity policy in June 2006. However, according to the '06-07 number of cases of back-door listing by the types' surveyed by KOSDAQ market headquarter, the number of cases of back-door listing rather increased since back-door listing regulation intensity, so it turned out necessary to conduct detailed analysis on the effects of back-door listing regulation intensity on the reliability of accounting information in the standpoint of the effectiveness of regulation intensity policy and the qualitative aspect of the policy. Therefore, this research performed positive analysis as follows on companies that attempted back-door listing. The research, first off, verified the effectiveness of back-door listing regulation intensity measure in current practice on the reliability of accounting information and secondly, predicted future trend of back-door listing structure change. Third, the research proposed policy for qualitative improvement of back-door listing with which back-door listing regulation may produce positive effects and policy for additional system improvement through which the listing elimination plan that will be enforced in February 2009 may not instigate back-door listing. Through such analysis, this research pursued to contribute to stabilization of sound M&A while improving the soundness of KOSDAQ market by eliminating negative functions of back-door listing and expanding positive functions. 본 연구는 우회상장의 규제강화가 회계정보의 신뢰성에 미치는 영향에 대하여 분석적으로 검토하였다. 우회상장이란, 비상장기업이 정상적인 기업공개(IPO)를 통하지 않고 상장기업과 합병 등의 방법으로 장내에 진입하는 것으로서 2003년 말 처음 용어가 사용된 이후 불과 4년의 짧은 기간 동안 M&A 시장에서 46.8%를 차지할 정도로 급속히 확산되었다. 우회상장은 부실상장기업의 시장구조조정이라는 순기능적 측면이 있으나 경상손실 및 자본침식 등의 역기능을 내포하고 있으며 금융위원회에서 실시한 ‘우회상장 실태 점검’결과 부실기업 간 결합으로 위험을 가중시키고 건전한 M&A를 저해하고 있는 것으로 나타났다. 이에 따라 2006년 6월 금융위에서 우회상장 규제강화 정책을 시행하기에 이르렀다. 그러나 코스닥 시장본부에서 조사한 ‘06-07년 유형별 우회상장 건수’에 의하면 우회상장 규제강화 이후에 우회상장 발생건수가 오히려 증가하고 있는 것으로 나타나 규제강화정책의 실효성과 정책의 질적 측면에서 우회상장 규제강화가 회계정보의 신뢰성에 미치는 영향에 대하여 보다 면밀한 분석이 필요하다. 따라서 본 연구에서는 우회상장을 시도한 기업들을 대상으로 다음과 같은 실증분석을 수행하였다. 첫째, 현재 실시되고 있는 우회상장 규제강화조치에 대해 회계정보의 신뢰성 측면에서 효과성을 검증하였고, 둘째, 향후 우회상장 구조의 변화추세를 예측해 보았다. 셋째, 우회상장의 규제가 우회상장의 제재로서만이 아닌 우회상장의 긍정적 기능을 살릴 수 있는 우회상장의 질적 향상을 위한 정책제언과 2009년 2월에 실시될 상장 퇴출 선진화 방안이 우회상장으로 이어지는 촉매재가 되지 않도록 추가적인 제도개선에 대한 정책제언을 하였다. 이와 같은 분석을 통하여 본 연구는 우회상장의 역기능적 측면을 제거하고 순기능적 측면을 확대함으로서 코스닥 시장의 건전성 제고와 더불어 건전한 M&A 정착에 기여할 수 있을 것으로 기대한다.

우회상장과 IPO에 대한 의사결정 비교연구

김종일,이장순 한국세무학회 2009 세무와 회계저널 Vol.10 No.3

This paper analyses the determinants of back-door listing in the KOSDAQ market by comparing the characteristics of back-door listing with those of initial public offerings(IPOs). The sample contains 458 new listings and 33 firms that carried out back-door listings even though they met the listing requirements. I estimated a logistic regression model of the probability of back-door listing by comparing newly listed firms with back-door listing firms that satisfy the official requirements for listing. The result shows that the size of a company and the leverage have a positive impact on the likelihood of a back-door listing. On the other hand, the firm's age and profitability have a negative significance on the decision to carry out back-door listing. In the presence of adverse selection, the probability of back-door listing should be negatively correlated with the age and/or the size of a company because of its track record. However, The findings indicate that the size of a company has a positive impact on the likelihood of a back-door listing. The findings also indicate that the leverage is a deterrent from going public due to close scrutiny by the authorities and positively correlated with a back-door listing. The probability of a back-door listing is negatively affected by the profitability because going public of firms with high profitability provides a benefit of financing large amount through public offering. This Study assessed characteristics of each method by comparatively analyzing backdoor listing and IPO. Both of two methods of listing on stock exchange, that is, IPO and backdoor listing, have double-edge of imparting positive or negative effect on the market, and companies select either of the methods in accordance with the companies' own characteristics. 본 연구의 목적은 IPO 요건을 갖추었음에도 불구하고 우회상장을 실시한 기업들의 특성을 분석하여 우회상장을 결정하는 요인을 파악하는데 있다. 이에 따라 본 연구에서는 코스닥시장을 대상으로 IPO 기업과 IPO 요건을 충족한 우회상장 기업들의 비교를 통해 우회상장을 촉진하거나 저해하는 요인을 분석하였다. 기존 연구에서는 전체 우회상장 기업을 대상으로 분석하였으나 본 연구에서는 우회상장 기업 중 IPO 요건을 충족한 기업, 합병 및 포괄적 주식교환 방법 등으로 우회상장을 실시한 기업 등으로 세분화하여 분석하였다. 2001년부터 2005년 동안 코스닥시장에 상장한 IPO 기업 458개와 우회상장 기업 154개 중 IPO 요건을 충족한 33개 기업을 대상으로 로지스틱회귀분석을 이용하여 실증분석을 수행하였다. 분석결과에 따르면 기업업력과 경상이익률은 예상대로 회귀계수가 음(-)으로 나타나 우회상장을 저해하는 요인으로 나타났으며 매출액 규모는 예상과는 다르게, 부채비율은 예상대로 회귀계수가 양(+)으로 나타나 우회상장을 촉진하는 요인으로 나타났다. 기업업력은 짧을수록, 기업규모는 커질수록 우회상장 가능성이 높아지는 것으로 나타나 저평가 가능성 측면에서 기업규모는 예측과는 다르게 관찰되었다. 부채비율이 높을수록, 경상이익률이 낮을수록 우회상장 가능성이 높게 나타나 안정성 및 수익성이 낮을수록 IPO보다 우회상장 가능성이 높아지는 것으로 나타났다. 실증분석결과 바이오와 엔터테인먼트업종은 우회상장 가능성이 높게 나타나지만 통계적으로 유의하게 관찰되지 않았으며 우회상장요건 적용대상 완화기간에는 예측대로 통계적으로 유의하게 우회상장 가능성이 높게 나타났다. 본 연구는 최근 우리사회에서 관심이 집중되는 우회상장에 대한 연구를 하였다. 코스닥시장은 중소기업 및 벤처기업 육성 차원에서 국가 경제적으로 중요하며 주식시장 상장은 기업의 지속적 성장 차원에서 경영자 개인적으로 중요한 의사결정이라고 볼 때, 어떠한 요인이 우회상장을 촉진하는지는 중요한 문제이다. 이러한 연구결과는 우회상장의 동기를 명확히 하여 우회상장을 고려하는 기업과 투자자 그리고 이를 규제하는 정책당국의 의사결정에 중요한 정보를 제공할 수 있다.

열가소성 폴리올레핀으로 구성된 범퍼 후방 보 개발에 관한 연구

안동규(Dong-Gyu Ahn),김세훈(Se-Hun Kim),박근성(Gun-Sung Park) Korean Society for Precision Engineering 2012 한국정밀공학회지 Vol.29 No.8

Recently, the application of the plastic material to automotive components and structures has steadily increased to satisfy demands on the saving of overall weight and the improvement of energy efficiency. The objective of this paper is to investigate the development of a bumper backbeam using a thermoplastic olefin (TPO). The bumper back-beam was designed to be manufactured from the injection molding process. In order to obtain a proper design of the bumper back-beam, three-dimensional finite element analyses were performed for various design alternatives. Stress-strain curves for different strain rates were measured by high speed tensile tests of the TPO to consider strain rate effects in the FEA. The influence of the sectional shape and the rib formation on the contact force-intrusion curves, the deflection and the energy absorption rate of the bumper back-beam was examined. From the results of the examination, a proper design of the bumper back-beam was acquired. The bumper back-beam consisting of TPO was fabricated from the injection moulding process and the vibration welding. Pendulum crash tests were carried out using the fabricated bumper back-beam. The results of the tests showed that the designed bumper back-beam can satisfy requirements of the federal motor vehicle safety standard (FMVSS). Through the comparison of the previously designed bumper back-beam with the newly designed bumper back beam, it was noted that the weight of the designed bumper back-beam is lighter than that of the previously designed bumper back beam by nearly 16 %. In addition, it was considered that the newly designed bumper back beam can improve recycling of the bumper back-beam.

Testing, simulation and design of back-to-back built-up cold-formed steel unequal angle sections under axial compression

G. Beulah Gnana Ananthi,Krishanu Roy,Boshan Chen,James B.P. Lim 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.33 No.4

In cold-formed steel (CFS) structures, such as trusses, transmission towers and portal frames, the use of back-to-back built-up CFS unequal angle sections are becoming increasingly popular. In such an arrangement, intermediate welds or screw fasteners are required at discrete points along the length, preventing the angle sections from buckling independently. Limited research is available in the literature on axial strength of back-to-back built-up CFS unequal angle sections. The issue is addressed herein. This paper presents an experimental investigation on both the welded and screw fastened back-to-back built-up CFS unequal angle sections under axial compression. The load-axial shortening and the load verses lateral displacement behaviour along with the deformed shapes at failure are reported. A nonlinear finite element (FE) model was then developed, which includes material nonlinearity, geometric imperfections and modelling of intermediate fasteners. The FE model was validated against the experimental test results, which showed good agreement, both in terms of failure loads and deformed shapes at failure. The validated FE model was then used for the purpose of a parametric study to investigate the effect of different thicknesses, lengths and, yield stresses of steel on axial strength of back-to-back built-up CFS unequal angle sections. Five different thicknesses and seven different lengths (stub to slender columns) with two different yield stresses were investigated in the parametric study. Axial strengths obtained from the experimental tests and FE analyses were used to assess the performance of the current design guidelines as per the Direct Strength Method (DSM); obtained comparisons show that the current DSM is conservative by only 7% on average, while predicting the axial strengths of back-to-back built-up CFS unequal angle sections.

日・印尼接触場面における日本語学習者と母語話者のあいづち的反応の機能 - 発話途中と発話交替時の比較考察 -

이순형 동북아시아문화학회 2017 동북아 문화연구 Vol.1 No.53

As the number of Japanese learners in Indonesia is the second largest in the world, contact situations between Japanese and Indonesian are expected to increase more. With this in mind, I carried out a comparative study on Indonesian learners of Japanese and Japanese native speakers to examine the functions of back-channels within and between utterances. The key findings are as follows. First, with the back channels within utterances used Japanese native speakers, most (69.4%) were for the function of ‘attentive listening’, but with back channels between utterances, there was no difference in the frequency of ‘attentive listening’, ‘understanding’ and ‘agreement’ functions. On the other hand, with the back channels within utterances used by Indonesian learners, the functions of ‘understanding’, ‘agreement’ and ‘attentive listening’ all accounted for about one third each, while with back channels between utterances the function of ‘agreement’ was the greatest (42.9%), with ‘attentive listening’ and ‘understanding’ less frequent in usage. Though low in frequency, this study also paid attention to the functions of ‘opposition’ and ‘emotional expression’. Within utterances, Japanese native speakers never use back channels for ‘opposition’ and merely 6.9% for ‘emotional expression’. Between utterances, they use the function of ‘emotional expression’ 13.6% of the time, in other words twice as much as within utterances. Within utterances, Indonesians use back channels for ‘opposition’ 1.5% and ‘emotional expression’ 2.9%, while between utterances they use ‘opposition’ 9.1%. For Japanese native speakers, it is likely that the functions of back-channels of ‘opposition’ can be a barrier to first face-to-face conversation, and disrupt conversation. ‘Attentive listening’ within utterances and ‘emotion’ between utterances are common among Japanese native speakers, but are less common in Indonesian learners. Even with Japanese native speakers, ‘attentive listening’ is more common within utterances than between utterances. Therefore, ‘attentive listening’ back channels within utterances and ‘emotion’ back channels between utterances can make Indonesian learners sound uninterested and can be a barrier to smooth conversation. However, because the function of ‘emotional expression’ shows active participation in conversation more than any other functions of back-channels, it needs to be introduced in Japanese language learning.