복합재활운동 프로그램이 슬관절 전치환술 노인 환자의 근력, 이동능력 및 균형감각에 미치는 영향

여효성(Yeo, Hyo-Seong),전유나(Jeon, Yu-Nah),하재여(Ha, Jae-Yeo) 한국웰니스학회 2017 한국웰니스학회지 Vol.12 No.3

이 연구는 퇴행성 관절염 환자의 슬관절 전치환술 후 저하되는 신체능력을 회복시킬 수 있는 효과적인 재활방법을 구명하고자 계획되었다 따라서 슬관절 전치환술 후 초기에 노인 여성 환자에게 복합재활운동 . 프로그램을 적용하여 하지의 근력, 이동능력, 균형감각의 변화를 확인하고자 하였다. 연구의 목적을 위해, 퇴행성 관절염을 가진 65세 이상 노인 여성 14명을 복합재활운동 집단(n=7)과 가정운동집단(n=7)으로 구분하였다. 복합재활운동 집단은 12주 동안 저항성 운동과 균형 운동을 병행하여 실시하였으며, 가정운동집단은 낮은 강도의 전통적인 재활운동을 실시하였다. 수술 전과 수술 후 12주간의 재활이 종료된 시점에 하지의 최대자발적 근 수축력, 이동 능력 그리고 균형능력을 측정하였다. 12주간의 복합재활운동을 실시한 노인 여성의 근력은 수술 전과 유의한 차이를 보이지 않았으나(p=.275), 가정운동을 실시한 집단의 근력은 수술 전에 비해 유의하게 낮았다(p=.001, -35.2%). 이와 유사하게 복합재활운동을 실시한 노인 여성의 이동능력은 수술 전과 유의한 차이를 보이지 않았지만(p=.639), 가정운동 집단에서는 수술 전에 비해 유의하게 낮았다(p=.002, -13.7%). 한편, 가정운동 집단의 균형능력은 수술 전 · 후 차이가 없었으며(p=.647), 복합재활운동집단의 균형능력은 훈련 후 수술 전에 비해 향상된 것으로 나타났다(p=.005, 12.5%). 이러한 결과들을 통해 복합재활 운동이 노인 여성 슬관절 전치환술 환자들의 신체기능 회복 및 기능개선에 긍정적인 영향을 미칠 가능성이 제안된다. The purpose of this study was to investigate the effective rehabilitation to regain physical abilities reduced after total knee arthroplasty (THA) of degenerative arthritis patients. Therefore, we applied combined rehabilitation exercise to aged female patients at early period after THA and observed the changes of lower limb muscle strength, mobility and balance. To purpose of the study, fourteen elderly female patients (age > 65yrs) undergone degenerative arthritis were assigned into combined rehabilitation exercise group (n=7) and home exercise group (n=7). Combined rehabilitation exercise group performed resistance exercise and balance exercise together and home exercise group conducted low level of traditional rehabilitation at home for 12 weeks. Maximal voluntary muscle contraction, mobility, and balance were measured before the surgery and after the 12 wk of rehabilitation. Muscle strength of combined rehabilitation exercise group was not changed (p=.275), however home exercise group showed significant lower muscle strength (p=.001, -35.2%). Likewise, in case of mobility, it was not changed in combined rehabilitation exercise group (p=.639), but reduced in home exercise group (p=.002, -13.7%). On the other hand, balance ability was not changed in home exercise group (p=.647), but significantly increased in combined exercise group after the training (p=.005, 12.5%). These results suggest that combined rehabilitation exercise may have a positive effect on recovery of physical function and ability of elderly female patients undergone THA.

공복시간이 유산소 운동후 흰쥐 심장근의 미토콘드리아 생합성에 미치는 영향

여효성(Yeo, Hyo-Seong),손희정(Son, Hee-Jung),권형태(Hyeong-Tae) 한국체육과학회 2017 한국체육과학회지 Vol.26 No.3

Mitochondrial biogenesis is controled through the transcriptional regulation PGC-1α, NRF-1, mtTFA and AMPK. Activation of AMPK by food deprivation is linked to the changes in the protein expressions of PGC-1 and related genes. This study was performed to determine the effect of food deprivation on mitochondrial biogenesis during aerobic exercise in left ventricular muscle. To achieve this purpose, male SD-rats (12 wk) were randomly assigned into Control (feeding, n=7), 6hF (6h fasting, n=7), 1hF+Ex (1h fasting + exercise, n=7), 3hF+Ex (3h fasting + exercise, n=7), 6hF+Ex (6h fasting + exercise, n=7). The exercise group was sacrificed at the time of 3hour after acute exercise (75∼80% VO2max). Expression of related proteins were analyzed by SDS-PAGE and western blotting. From the results of this study, expression of AMPK(76%, p=.001), PGC-1α(137%, p=.001), NRF-1(84%, p=.001), mtTFA(129%, p=.001) and COX-IV(76%, p=.001) in 6hF+Ex(6h fasting + exercise) group were significantly greater than Control (feeding) group, as well as AMPK(68%, p=.001), PGC-1α(87%, p=.001), NRF-1(48%, p=.001), mtTFA(57%, p=.001) and COX-IV(67%, p=.001) in 3hF+Ex(3h fasting + exercise) group were significantly greater than Control(feeding) group. This study demonstrates that the aerobic exercise after 6h fasting has optimal effect on mitochondrial biogenesis in heart muscle.

유색미 겨 아라비녹실레인 섭취와 지구성 운동트레이닝이 흰쥐의 근섬유 유형별 HSL과 LPL 단백질 발현에 미치는 영향

여효성(Yeo, Hyo-Sung),이상호(Lee, Sang-Ho),손희정(Son, Hee-Jeong) 한국체육과학회 2015 한국체육과학회지 Vol.24 No.5

Arabinoxylan is one of the potential key products of a rice bran based biorefinery. Arabinoxylan rice bran has been shown to be a potent biological response modifier. In most country, obesity and related diseases have emerged as major health problems. Hormone-sensitive lipase (HSL) is important for the degradation of triacylglycerol in adipose and muscle tissue, but the tissue-specific regulation of this enzyme is not fully understood. We investigated the effects of Ara rice bran and exercise on the fat metabolism in rats. As the results, HSL as a major enzyme involved in triacylglycerol lipolysis showed a significantly higher in exercise group and Ara supplement group and Ara supplement with exercise group in EDL muscle. Whereas, LPL(lipoprotein lipase) as a second enzyme in lipolysis showed a significantly lower in Ara supplement with exercise group, thus the Ara supplement with exercise group had a higher inhibitory activity than the both exercise and Ara supplement group in EDL muscle. However, HSL enzyme in all group significantly decreased than control group in soleus muscle. These results require further research and suggest that the supplement of Ara rice bran with exercise is likely contribute to triacylglycerol lipolysis response in only EDL muscle of rat. Through a further study, the effect of ara rice bran can be confirmed as a possible safe alternative to the treatment modalities.

아라비녹실란 섭취와 유산소성 운동 중재에 따른 혈중 면역글로불린 및 지질 농도의 차이 분석

여효성(Yeo, Hyo-Seong),권형태(Kwon, Hyeong-Tae),손희정(Son, Hee-Jeong) 한국체육과학회 2017 한국체육과학회지 Vol.26 No.3

Arabinoxylan extracted from rice bran has an impact on developing immune function and lipid metabolism. Regular aerobic exercise might improve serum immunoglobulin (Ig) concentration with B cell proliferation. Therefore, this study was planned to investigate the effect of arabinoxylan ingestion and regular aerobic exercise in rats for 4 weeks. Thirty-two Sprague-Dawley rats (aged 8wks) were divided into CON(control, n=8), ARA(arabinoxylan, n=8), EXE(aerobic exercise, n=8) and ARA+EXE (arabinoxylan+aerobic exercise, n=8) groups. ARA group was orally ingested with arabinoxylan for 4 weeks. EXE group ran on the rodent treadmill at 15m/min for 4 weeks (5d/w). ARA+EXE group performed both arabinoxylan ingestion and exercise for the same duration. Serum IgA, IgM, IgG concentration and TG, FFA, TC, HDL-C and LDL-C were anlayzed by ELISA kits. The concentration of IgA of ARA(p=.006), EXE(p=.027) and ARA+EXE(p=.013) were significantly higher than that of CON. However, IgM and IgG level had no differences between groups(p >.05). TC level of ARA and EXE were significantly lower than that of CON(p<.05), however there were no differences between groups in other lipid profiles(p>.05). Taken together, regular arabinoxylan ingestion and aerobic exercise can increase IgA concentration, which improves immune function of mucous membrane and upper respiratory system.

저항성 운동과 유산소 운동 훈련의 병행이 노화쥐 골격근 유형별 혈관신생 관련 단백질 발현에 미치는 영향

여효성(Hyo-Seong Yeo) 한국응용과학기술학회 (구.한국유화학회) 2021 한국응용과학기술학회지 Vol.38 No.3

이 연구는 노화된 흰쥐를 대상으로 규칙적인 저항성 운동에 유산소 운동을 병행하는 훈련을 실시하여 골격근에서 나타나는 혈관신생 관련 단백질 발현의 반응을 관찰하기 위해 수행되었다. 연구의 목적을 위해 자연적으로 노화된 SD계열 흰쥐(20-24개월령, N=18)를 사용하여 통제(CON, n=6), 저항성 운동 (RE, n=6), 저항성+유산소 운동(RE+AE, n=6) 집단으로 구분하였다. 저항성 운동 집단은 실험동물용 사다 리를 이용하여 매회 3세트×4회의 운동을 실시하였고 저항성 운동+유산소 운동 집단은 매회 2세트×3회의 사다리 오르기와 추가적인 30분간의 트레드밀 달리기를 수행하였다. 총 8주간의 운동 훈련 종료 후 가자미 근과 장지신근을 적출하여 분석에 사용하였다. 골격근에서 혈관신생 관련 단백질들(HIF-1α, VEGF, FLK-1, Ang-1, Ang-2)의 발현 수준을 분석하기 위해 western blot을 실시하였다. 연구결과, 저항성+유산소 운동 집단에서 가자미근(type I 근육)의 HIF-1α, VEGF, FLK-1, Ang-1, Ang-2 단백질 발현이 통제 집단에 비해 높았으며 저항성 운동만 수행할 경우 HIF-1α, VEGF, Ang-1, Ang-2 단백질 발현이 통제 집단에 비해 높았다. 또한 가자미근에서 저항성+유산소 운동훈련 집단의 Ang-2 to Ang-1 ratio가 저항성 운동 집단에 비해 높아 운동훈련 유형별 차이를 보였다. 한편, 장지신근(type II 근육)에서 HIF-1α는 저항성 운동 훈련에 의해서만 증가된 반면 VEGF와 FLK-1 단백질 발현은 두 훈련 유형 모두에서 증가되었고 운동 훈련 유형별 차이는 관찰되지 않았다. 또한 장지신근의 angiopoieitin 단백질들의 발현은 운동 훈련에 의한 차이가 없었다. 그러므로 노화에서 규칙적인 운동 훈련은 운동 유형에 관계없이 골격근 혈관신생 반응을 유도하며, 특히 저항성 운동에 유산소 운동의 병행은 type I 근조직 유형에서 혈관신생에 대한 추가적인 긍정적 효과를 가질 수 있다. This study was performed to observe the responses of angiogenesis-related protein expression in skeletal muscle of aged rats by regular resistance exercise training with aerobic exercise. For the purpose of the study, naturally aged SD rats (20-24 months, N=18) were used and divided into control (CON, n=6), resistance exercise (RE, n=6), and resistance + aerobic exercise (RE + AE, n=6) groups. RE group performed 3 sets × 4 exercises each session using a ladder for laboratory animals, and RE +AE group performed 2 sets × 3 times of ladder climbing and additional treadmill running (30 min) each session. After 8 weeks of exercise training, soleus muscle and extensor digitorum longus muscle (EDL) were extracted and used for analysis. Western blot was performed to analyze the expression levels of angiogenesis-related proteins (HIF-1α, VEGF, FLK-1, Ang-1, Ang-2) in skeletal muscle. As a result of the study, the expression of HIF-1α, VEGF, FLK-1, Ang-1, and Ang-2 proteins in soleus muscle (type I muscle) was higher in RE +AE than in CON group, and HIF-1α, VEGF, Ang-1, Ang-2 protein expression of RE group was higher than that of CON group. Furthermore, Ang-2 to Ang-1 ratio of RE + AE group was higher than that of RE group, showing differences by exercise type. In EDL muscle (type II muscle), HIF-1α was increased only by RE group, whereas VEGF and FLK-1 protein expressions were increased in both training types, and no difference was observed between the types of exercise training. In addition, there was no difference in angiopoieitin protein expressions in EDL muscle by exercise training. Therefore, in aging, regular exercise training induces skeletal muscle angiogenic response regardless of exercise type, and in particular, the combination of aerobic exercise with resistance exercise may have an additional positive effect on angiogenesis in type I muscle.

정신분열증 유도 쥐에서 운동과 좌심실 세포사멸의 반응

여효성(Yeo, Hyo-Seong),홍영표(Hong, Young-Pyo),이삼준(Lee, Sam-Jun) 한국체육과학회 2017 한국체육과학회지 Vol.26 No.5

Schizophrenia is a neuropsychiatric disease accompanying with psychological, emotional and behavioral disorders. Lifespan of patients with schizophrenia is 11 to 20 years shorter than general people which might be associated with cardiovascular disease. Although apoptosis is highly related to cardiovascular disease, to date there is no study observing apoptotis in heart with schizophrenia. Therefore, we tried to investigate the expression of apoptotic proteins in rats with schizophrenia and the effect of regular aerobic exercise. Twenty-one SD rats were assigned to CON (control, n=7), SCH (schizophrenia, n=7), SCH+EXE (schizophrenia+exercise, n=7) groups. SCH and SCH+EXE groups were treated with MK-801 using i.p. injection for schizophrenia. SCH+EXE group ran on the rodent treadmill at 2 2m/min for f our w eeks ( 5days/week, 3 0min/day). A poptotic p roteins including b ax, bcl-2, cytochrome-c, caspase-3 in left ventricle were analyzed by western blotting. From the results, the expression of bax (p=.001), cytochrome-c (p=.035) and caspase-3 (p=.001) in SCH group were significantly higher than in CON group. On contrary, SCH+EXE group showed the significantly lower expression of bax (p=.009) and caspase-3 (p=.027) than CON group. There was no difference of bcl-2 protein between groups (p>.05), however bax/bcl-2 ratio was higher in SCH (p=.026) than in CON group, as well as it was lower in SCH+EXE (p=.004) than SCH group. These results suggest that increased apoptotic level in heart by inducing schizophrenia could be attenuated by regular aerobic exercise.

필라테스 재활운동 프로그램이 만성요통 노인환자의 균형능력, 이동성 및 통증에 미치는 영향

여효성(Hyo Seong Yeo),하재여(Jae Yeo Ha) 한국발육발달학회 2019 한국발육발달학회지 Vol.27 No.2

Chronic low back pain is a major health problem worldwide, particularly in elderly population. Interventions based on exercise have been the most commonly used treatments for patients with this condition. Over the past few years, the Pilates method has been one of the most popular rehabilitation exercise programs used in clinical practice. Therefore, the purpose of this study was to confirm the effects of regular Pilates exercise on balance, mobility and pain in elderly patients with chronic low back pain. Fourteen elderly participants with chronic low back pain (age, 66.7 ± 1.4 years; height, 157.0 ± 4.1 cm; weight, 59.0 ± 4.6 kg; BMI, 23.9 ± 1.6 kg/m²) were randomly allocated to either a Pilates exercise group (EX, n=7) or a control group (CON, n=7). EX group performed exercise sessions with physiotherapy conducted over an 12-week period (3 sessions/week), while CON group attended only physiotherapy over the same period. The level of static balance, mobility and pain were measured 48-hours before and after the exercise program and compared to assess training effects. Static balance ability by MFT of EX group was significantly improved after the Pilates program (p=.003, -21%), whereas there was no change in CON group (p>.05). The MFT score was significantly lower in EX group than in CON group (p=.009, -21%). Likewise, mobility was improved by reducing TUG score in EX group (p=.001, -21%) after the program and the score was lower in EX group compared to CON group (p=.001, -17%). The level of pain was lowered both in EX group (p=.001, 42%) and CON group (p=.014, 11%), but there was no significant difference between groups (p>.05). These results provide initial evidence that regular Pilates rehabilitation exercise may enhance balance and mobility and reduce pain in elderly patients with chronic low back pain.

유산소 운동수행이 흰쥐 골격근의 면역관련 TLR4 단백질의 신호전달 활성에 미치는 영향

여효성 ( H. S. Yeo ),김효정 ( H. J. Kim ),김창근 ( C. K. Kim ) 한국운동생리학회(구-한국운동과학회) 2012 운동과학 Vol.21 No.2

활동은 세포 내의 다양한 신호경로를 자극하고 유전자 전사의 변화를 유도할 뿐 만 아니라 면역기능과 염증 민감성에 영향을 미친다. 일반적으로 좌식 생활자는 만성적 염증반응을 나타내는 반면 적절한 신체 활동은 염증반응을 감소시키며 일회성 고강도 운동수행은 다양한 면역 세포들의 염증반응을 증가시킨다. 운동으로 인한 염증반응의 증가는 근손상을 초래하며, 혈액에서의 염증성 cytokine 증가는 근 단백질 합성 저하 및 제지방량 감소와 관련있는 것으로 보고되었다. 운동에 의한 면역 및 염증반응과 관련된 지표로 Toll-like receptors (TLRs)가 제시되고 있다. TLRs는 미생물 병원체(microbial pathogen)의 특정 패턴을 인식하여 TNF-α와 같은 염증 반응을 일으키는 유전자를 발현시킴으로써 면역 활동을 조절한다. TLRs은 인체의 지방, 간, 근육 조직을 포함하는 다양한 세포에서 발현되며 이중 TLR4는 세포막에 존재하며 Lipopolysaccharide (LPS)에 반응하여 전신의 염증반응을 조절한다. TLR4 signaling은 MyD88 의존형과 MyD88 비의존형으로 나뉘며 최종적으로 NFκB를 활성화시켜 염증반응에 관여한다. 이 연구는 12주령 실험용 쥐(SD-Rat) 35마리를 대상으로 실험동물용 트레드밀을 이용하여 최대산소섭취량의 약75~85% 수준(28 m/min)으로 지구성 운동을 수행시킨 후, 운동직후, 운동 후 30분, 운동 후 1시간, 운동 후 6시간에 Extensor Digitorum Longus (EDL)를 적출하여 TLR4 관련 단백질 발현의 변화를 SDS-PAGE 와 Western blotting을 통해 분석하였다. 실험을 통해 TLR4단백질은 운동 후 점차적으로 유의하게 감소하여 운동 후 회복기 6시간 시점(42%)에 최대 감소율을 보였다. MyD88 단백질은 운동후 회복기에 유의한 변화가 없었다. 또한 전사인자인 NFκB는 운동 후 점차적으로 증가하는 경향을 보이며 운동 후 1시간(51%)에 유의하게 증가하였고 회복기 6시간 후에 기저수준으로 감소되었다. 이상의 결과는 TLR4와 NFκB 발현에서의 연관성과 함께 지구성 운동 후 회복기에 골격근에서 나타나는 TLR4의 감소가 염증반응에 대한 방어 효과를 나타낼 가능성을 보여주고 있다. The innate immune response is the first line of defence against infectious disease. A group of proteins that comprise Toll or Toll-like family of receptors (TLRs) has been suggested as one of the markers associated with immune and inflammatory responses. TLR4 among the TLRs produces a response by lipopolysaccharide (LPS) and controls inflammatory responses. This study was performed to demonstrate the change of TLR4 signaling-mediated protein expressions in skeletal muscle during the recovery of an intensive endurance exercise. Sprague-Dawley rats (12 week, n=35) were randomly divided into five groups(n=7 each) to time period of the exercise (pre, post 0 h, 30min, 1 hr and 6 hrs). The rats ran on the rodent treadmill for 1 hour at the level of 75~80% VO2max (28 m/min). The change of TLR4, MyD88 protein expression and NFκBp65 DNA binding activity were analyzed by western blotting in Extensor Digitorum Longus (EDL) muscle. TLR4 protein expression was significantly decreased by 41%(p=.036) at 6hrs of recovery with the intensive endurance exercise whereas MyD88 was not changed. NFκB was significantly increased by 51%(p=.014) at 1h of recovery but returned to the resting level at 6 hrs of recovery. These results suggest a possibility of an interaction between TLR4 and NFκB expression and the exercise-induced changes in these molecules during recovery period may a key role to defence inflammatory response in rat skeletal muscle.

Pichia anomala JK04와 Saccharomyces cerevisiae Fermivin 혼합발효에 의한 캠벨얼리 와인과 아로니아 와인의 블렌딩 효과

정효성,이새벽,여수빈,김다혜,최준수,김동환,여수환,박희동,Jeong, Hyo-sung,Lee, Sae-Byuk,Yeo, Su-bin,Kim, Da-Hye,Choi, Jun-Su,Kim, Dong-Hwan,Yeo, Soo-Hwan,Park, Heui-Dong 한국식품저장유통학회 2017 한국식품저장유통학회지 Vol.24 No.3

본 연구는 국산 캠벨얼리 와인의 주질 개선과 기능성 향상을 위해 캠벨얼리 뿐만 아니라 안토시아닌과 폴리페놀 성분이 풍부하여 항산화능이 우수하다고 알려진 아로니아를 이용하여 상업용 효모인 S. cerevisiae Fermivin과 향미증진능을 지닌 P. anomala JK04를 각각 단독 또는 5:5(v/v)의 비율로 혼합발효한 후 블렌딩하는 실험을 진행하였다. 최적 블렌딩 비율을 정하기 위하여 예비실험으로 캠벨얼리 와인에 아로니아 와인을 각각 5, 10, 20%(v/v) 첨가하여 항산화능과 관능검사를 실시하였으며, 실험 결과를 바탕으로 캠벨얼리 와인과 아로니아 와인의 블렌딩 비율을 9:1(v/v)로 설정하였다. P. anomala JK04로 단독발효한 캠벨얼리 와인은 낮은 알코올 함량으로 인해 블렌딩에서 제외하였고, 나머지는 발효에 이용된 균주에 따라 블렌딩하였다. 블렌딩와인의 기능성을 평가하기 위하여 총 안토시아닌 함량, DPPH 라디칼 소거능, 총 페놀성 화합물 함량 분석을 진행하였으며, 모든 블렌딩와인에서 대조구인 S. cerevisiae로 단독발효한 캠벨얼리보다 높은 수치를 나타내었다. 블렌딩와인의 유리당 분석 결과에서는 P. anomala JK04로 단독발효한 아로니아 와인을 첨가한 시험구(A,D)에서 glucose와 fructose 같은 잔당이 남아있는 것을 확인하였으며, 유기산 분석 결과에서는 상기 두 시험구에서 특히 malic acid 함량이 높게 측정되었다. 블렌딩와인의 외관적 품질을 검사하기 위해 색도, 휘발성 향기성분, 관능검사가 수행되었으며, P. anomala JK04를 사용 여부에 따라 A, B, C와 D, E, F 순으로 hue와 intensity 값이 증가하는 경향을 나타내었다. 또한 Hunter's color value에서는 아로니아 와인의 첨가가 와인의 a value와 b value를 증가시키는 경향을 나타내었다. 휘발성 향기성분분석에서는 P. anomala JK04의 사용이 와인에 부정적인 성분인 aldehyde와 acid 함량이 소폭 증가시키긴 하였지만, 중요한 향기성분은 ester 화합물의 함량이 큰 폭으로 증가하는 것을 확인하였다. 관능검사 결과에서는 P. anomala JK04로 단독발효한 아로니아 와인을 사용한 시험구(A,D)에서 색, 맛, 신맛, 전반적인 기호도에서 다른 시험구보다 높은 점수를 받았으며, 향기 항목에서는 모든 블렌딩와인이 대조구보다 높은 점수를 받았다. 본 연구에서는 캠벨얼리 와인에 아로니아 와인을 블렌딩하여 기능성을 증가시켰으며, S. cerevisiae Fermivin과 P. anomala JK04를 혼합발효하여 향기성분의 증가 및 관능적 품질이 향상됨을 확인하였다. To improve functionality and palatability of Korean Campbell Early wine. Campbell Early and aronia were fermented by either individually or at 5:5 (v/v) mixed culture of Saccharomyces cerevisiae Fermivin and Pichia anomala JK04. Blending was carried out using those two wines with different mixing ratio. Antioxidant activity analysis and sensory evaluation of blending wines were conducted. The Campbell Early wine and aronia wine blended with 9:1 (v/v) ratio showed excellent antioxidant activity and sensory scores. Total anthocyanin compound, DPPH radical scavenging activity and total phenolic compound of blending wines were higher than those of Campbell Early wine (control). Hue and intensity values increased in the order of A, B, C and D, E, F depending on P. anomala JK04 use. Anonia wine contributed the increase in a and b values of blending wine. Although blending wines fermented by P. anomala JK04 increased small amounts of aldehyde and acid compound, ester compound, the most important factor for wine aroma was also increased sharply. Adding aronia wine fermented by single culture of P. anomala JK04 (A, D) got higher color, taste, sourness and overall preference scores than other wines in the sensory evaluation. All of blending wines showed higher flavor scores than control did. This research shows a possibility of blending and utilizing non-Saccharomyces yeast for Korean wine industry.

금융변수의 주가수익률 예측력 검정

김현석 ( Hyunseok Kim ),여효성 ( Hyosung Yeo ) 한국금융학회 2017 금융연구 Vol.31 No.1

본 연구는 한국주식시장을 대상으로 배당수익률, 이익주가 비율(E/P 비율), 이자율, Yield Gap과 같은 금융변수의 주가수익률 예측력을 검정하였다. 이를 위해 예측회귀분석 시 발생 가능한 계량적 문제들을 효과적으로 처리하기 위하여 Choi, Jacewitz, and Park(2016)의 변동성 시계 표본을 이용한 Cauchy 추정법을 적용하여 실증분석을 수행하였으며, 주요한 분석 결과는 다음과 같다. 첫째, 주가수익률의 QV(quadratic variation)을 기반으로 변동성 시계로 변환한 모형에서는 어떤 변수도 주가수익률 예측력을 가지지 못하는 것으로 나타났지만, 주가수익률의 BPV(bipower variation)을 기반으로 변동성 시계로 변환한 모형에서는 배당수익률이 주가수익률 예측력을 가지는 것으로 나타났다. 둘째, 장단기 Yield Gap의 주가수익률 예측력 검정 결과, 장단기 Yield Gap 중 어느 변수도 주가수익률 예측력을 가지지 못하는 것으로 나타났다. 본 연구는 금융변수의 주가수익률 예측력 검정 시 나타날 수 있는 다양한 문제들을 새로운 계량적 기법을 사용하여 효과적으로 처리하였다는 점에서 기존연구와 차별성을 가진다. 또한 주가수익률에 대한 예측 변수로서 선진금융시장에서 흔히 사용되는 Yield Gap을 소개하고, 이의 주가수익률 예측가능성을 추가적으로 검정하였다는 점에서 보다 진일보된 실증분석 연구로서의 의미를 갖는다. In this paper, we examine stock return predictability in the Korean stock market using the random time Cauchy estimator. Various financial variables have been tested for stock return predictability, but the results remain inconclusive. In the Korean stock market, Kim and Kim (2004), Kim and Park (2009) and Chung and Kim (2010) try to find evidence of return predictability using the dividend-price ratio, earnings-price ratio, and interest rates, but their conclusions are mixed. More recently, Choi et al. (2016) propose a robust test of stock return predictability which combines the time-change method with a Cauchy estimator. They show that the random time Cauchy test has an exact size of test and comparable power to Campbell and Yogo (2006) and Chen and Deo (2009)`s tests. We apply this new methodology to the KOSPI index and report the empirical results, providing comparison with other widely used tests for return predictability. Stock returns have nearly nonstationary stochastic volatility, and this causes substantial size distortions on standard tests relying on constant variance. To handle this nonstationary stochastic volatility in returns, we implement a simple time change. For the required time change, “we wait for volatility to reach a certain threshold before collecting each observation such that there is a constant level of volatility across all observations in our sample.”(Campbell and Yogo, 2006) Using the daily KOSPI index, we first test the presence of discrete jumps in our sample. We detect a total of 15 jumps between January 2001 and December 2014 with the windows size 16 and a 5% significance level, using Lee and Mykland (2008) test. Depending on the presence of discrete jumps, we measure the realized variance and realized bi-power variation. When we allow for only the continuous martingale in the regression error, we remove the detected daily jumps and compute the total realized variance by squaring and summing up daily excess returns. When we allow our continuous time regression model to have discrete jumps, we compute the realized total bi-power variation without removing detected jumps. We have a total of 168 months in our sample span. The computed total realized variance (TQV) and total realized bi-power variation (TBPV) are then divided by the number of months and we set this as our volatility threshold △<sub>QV</sub> and △<sub>BPV</sub> for a time change with QV and a time change with BPV, respectively. Using the given volatility threshold, we add up daily squared excess returns until it hits our set △ and resample our regression variables on that date and repeat the process until we reach the TQV and TBPV. After correcting for stochastic volatility in returns, we implement a Cauchy estimator to handle the persistent endogeneity of covariates. The Cauchy estimator uses the sign transform of a covariate as an instrumental variable. “The advantage of using a Cauchy estimator is that the asymptotic normality of the Cauchy t-ratio holds regardless of any statistical anomalies in covariates including nonstationarity, fat-tailed innovations, structural breaks, and jumps.” (Choi et al., 2016) Thus, it is well suited for testing return predictability in cases where many commonly used covariates are highly persistent and correlated with the regression residuals. Inferences using the Cauchy t-ratio are also valid even in the presence of structural breaks and jumps. We test for stock return predictability in the Korean market using the log of dividend-price ratio, the log of earnings-price ratio, the riskfree rate, and short-term, medium-term and long-term yield gaps. For the dividend-price ratio, conventional OLS t-test over-rejects the null hypothesis of no predictability. We could not find evidence for predictability using other tests except the random time Cauchy with BPV. For the earnings- price ratio, none of our tests reject the null. The coefficients of risk-free rates are insignificant except for Campbell and Yogo (2006)`s BQ test where its 90% confidence interval does not include zero value. Using the Amihud and Hurvich (2004) and Campbell and Yogo (2006)`s test, shortterm yield gap has predictive power. But using the Chen and Deo (2009)`s chi-square 1 and random time Cauchy t-test, we could not reject the null. After correcting for persistent endogeneity in the medium-term yield gap, evidence for return predictability disappears, and all our tests except for OLS t-test cannot reject the null. Finally, we could not find any evidence for predictability using the long-term yield gap.