Effect of Feeding Time Shift on the Reproductive System in Male Rats

Kwak Byung-Kook,Lee Sung-Ho 한국발생생물학회 2012 발생과 생식 Vol.16 No.1

Circadian rhythmicity (e.g. secretory pattern of hormones) plays an important role in the control of reproductive function. We hypothesized that the alteration of feeding pattern via meal time shift/restriction might disrupt circadian rhythms in energy balance, and induce changes in reproductive activities. To test this hypothesis, we employed simple animal model that not allowing feeding but daytime only feeding. The animals of feeding group (Control) have free access to food for 4 weeks. The day feeding (=reverse feeding, RF) animals (RF group) have restricted access to food during daytime (0900-1800) for 4 weeks. After completing the feeding schedules, body weights, testis and epididymis weights of animals from both group were not significantly different. However, the weights of seminal vesicle (control : RF group = : , <0.01) and prostate (control : RF group = : , <0.001) were significantly lower in RF group animals. The mRNA levels of pituitary common alpha subunit (; control : RF group = AU : AU, <0.001) and (control : RF group = AU : AU, <0.05) were significantly decreased in RF group. The mRNA levels of ACTH were not significantly different. We were unable to find any prominent difference in the microstructures of epididymis, and there were slight alterations in those of seminal vesicles after 4 weeks of reversed feeding when compared to control samples. The present study demonstrates that the shift and/or restriction of feeding time could alter the pituitary gonadotropin expression and the weights of seminal vesicle and prostate in rats. These data suggest the lowered gonadotropin inputs may decrease androgen secretion form testis, and consequently results in poor response of androgen-dependent tissues such as seminal vesicle and prostate.

Segmental Prevalence and Extraction Rate of Retained Intrahepatic Stone

Kwak, Byung Kook,Lee, Jong Beum,Joo, Sang Shin,Lee, Hwa Yeon,Shim, Hyung Jin,Kim, Kun Sang,Lee, Yong Chul 중앙대학교 의과대학 의과학연구소 1996 中央醫大誌 Vol.21 No.2

간내 잔류담석의 간 구역별 빈도와 제거율과 실패원일을 알고자 한다. 담석증으로 수술을 받고 T자관을 통하여 잔류담석 제거술을 시행 받은 환자중 간내담도에 잔류담석이 있던 126명을 후향적으로 담도조영사진을 분석하였다. 간내담도별 잔류 단석의 빈도와 제거율은 좌외측(left lateral)이 각각 54.0%, 91.1% ; 우후(right posterior)가 38.1%, 81.2% ; 우전(right anterion)이 26.2%, 93.8% ; 좌 내측(left medial)이 14.3%, 77.7%를 보였다. 전체 제거율은 85.6%이었다. 미상엽은 모든 예에서 간내 담석이 없었다. 제거 실패의 주된 원인은 담도 협착과 매복된 담석이었다. 우후와 좌내측 간내담도에서는 고유한 담도의 굴곡이 또 하나의 실패의 주된 원인이었다. 결론적으로 좌외측 간내담도가 담석의 빈도가 가장 높고 우후, 우전, 좌내측 간내담도의 순서로 높았다. 우후와 좌내측 간내담도의 담석제거율이 우전, 좌외측 보다 낮았으며, 이것은 고유한 굴곡 대문으로 설명된다. To evaluate the hepatic segmental prevalence and the extraction rate of the retained intrahepatic stones on cholangiogram and the cause of failure of percutaneous stone removal through a T-tube tract. One hundred and twenty-six patients who had undergone the extraction of the retained intrahepatic stones were evaluated. Selective segmental cholangiogrmas were obtained for each segmental prevalence by using a pre-shaped 10F catheter. The results of the segmental extraction rate and the cause of failure were also evaluated after completing the stone removal session. The segmental prevalence and the extraction rate were 54.0% and 91.1% in the left lateral(LL), 38.1% and 81.2% in the right posterior(RP), 26.2% and 93.8% in the right anterior(RA), 14.3% and 77.7% in the left medial(LM) segmental duct, respectively. The total extraction rate was 85.6%. The caudate lobe had no stone in all cases. The main causes of extraction failure were stricture and stone impaction. In the RP and the LM segmental duct, duct angulation was another amin cause of failure. The prevalence of retained stones is highest in the LL segmental duct, the RP, the RA and the LM segmental duct, in descending order. There was no stone in the caudate lobe. The extraction in the RP and LM segmental ducts is more difficult than in the RA and LL segmental ducts. This result can be explained by the natural anatomical angulation of these ducts.

Effect of Feeding Time Shift on the Reproductive System in Male Rats

Byung Kook Kwak,이성호 한국발생생물학회 2012 발생과 생식 Vol.16 No.1

Circadian rhythmicity (e.g. hormone secretory pattern of hormones) plays an important role in the control of reproductive function. We hypothesized that the alteration of feeding pattern via meal time shift/restriction might disrupt circadian rhythms in energy balance and induce changes in reproductive activities. To test this hypothesis, we employed simple animal model that not allowing ad libitum feeding but daytime only feeding. The animals of ad libitum feeding group (Control) have free access to food for 4 weeks. The day feeding (=reverse feeding) animals (RF group) have restricted access to food during daytime (09:00-1800) for 4 weeks. After 4 weeks of feeding, body weights, testis and epididymis weights of animals from both group were not significantly different However, the weights of seminal vesicle (control:RF group=0.233±0.014 g:0.188±0.009 g, p<0.01) and prostate (control:RF group=0.358±0.015 g:0.259±0.015 g, p<0.001) were significantly lower in RF group animals. The mRNA levels of pituitary common alpha subunit (Cα; control : RF group=1.0±0.0699 AU : 0.1923±0.0270AU, p<0.001, Fig. 1A) and FSHβ (control : RF group= 1.0±0.1489AU :0.5237±0.1088AU, p<0.05, Fig. 1C) were significantly decreased in RF group. The mRNA levels of ACTH were not significantly different. We were unable to find any prominent difference in the microstructures of epididymis and slight alterations in the those of seminal vesicles after 4 weeks of reversed feeding when compared to control samples. The present study demonstrates that the shift and/or restriction of feeding time could alter the pituitary gonadotropin expression and the weights of seminal vesicle and prostate in rats. These data suggest the lowered gonadotropin inputs may decreases androgen secretion form testis, and consequently results in poor response of androgen-dependent tissues such as seminal vesicle and prostate.

간동맥 화학색전술에 사용하는 색전물질에 대한 고찰

곽병국 ( Byung Kook Kwak ),심형진 ( Hyung Jin Shim ) 대한간암학회 2011 대한간암학회지 Vol.11 No.1

Four procedures on intraarterial catheter-based therapy are available in treating hepatocellular carcinoma: intraarterial chemotherapy (IAC), transcatheter arterial embolization (TAE), conventional transcatheter arterial chemoembolization (cTACE), and transcatheter arterial chemoembolization using drug-eluting bead (DEB-TACE). On the bases of 2009 Practice Guideline for Diagnosis and Treatment of Hepatocellular Carcinoma by The Korean Liver Cancer Study Group and National Cancer Center, and 2010 AASLD Practice Guideline by American Association for the Study of Liver Disease, substances and recommendations on interventional managements were reviewed. Various kinds of embolic materials used in the procedures of TAE, cTACE and DEB-TACE were described in detail.

CPWL : Clock and Page Weight based Disk Buffer Management Policy for Flash Memory Systems

Byung Kook Kang(강병국),Jong Wook Kwak(곽종욱) 한국컴퓨터정보학회 2020 韓國컴퓨터情報學會論文誌 Vol.25 No.2

IT 산업 환경에서 모바일 데이터의 수요 증가로 인해 NAND 플래시 메모리의 사용이 지속적으로 증가하고 있다. 하지만, 플래시 메모리의 소거 동작은 긴 대기 시간과 높은 소비 전력을 요구하여 각 셀의 수명을 제한한다. 따라서 쓰기와 삭제 작업을 자주 수행하면 플래시 메모리의 성능과 수명이 단축된다. 이런 문제를 해결하기 위해 디스크 버퍼를 이용, 플래시 메모리에 할당되는 쓰기 및 지우기 연산을 감소시켜 플래시 메모리의 성능을 향상시키는 기술이 연구되고 있다. 본 논문에서는 쓰기 횟수를 최소화하기 위한 CPWL 기법을 제안한다. CPWL 기법은 버퍼 메모리 액세스 패턴에 따라 읽기 및 쓰기 페이지를 나누어 관리한다. 이렇게 나뉜 페이지를 정렬하여 쓰기 횟수를 줄이고 결과적으로 플래시 메모리의 수명을 늘리고 에너지 소비를 감소시킨다. The use of NAND flash memory is continuously increased with the demand of mobile data in the IT industry environment. However, the erase operations in flash memory require longer latency and higher power consumption, resulting in the limited lifetime for each cell. Therefore, frequent write/erase operations reduce the performance and the lifetime of the flash memory. In order to solve this problem, management techniques for improving the performance of flash based storage by reducing write and erase operations of flash memory with using disk buffers have been studied. In this paper, we propose a CPWL to minimized the number of write operations. It is a disk buffer management that separates read and write pages according to the characteristics of the buffer memory access patterns. This technique increases the lifespan of the flash memory and decreases an energy consumption by reducing the number of writes by arranging pages according to the characteristics of buffer memory access mode of requested pages.

A Study on a New Design Method of the PO-type Fuzzy Logic Controller

Byung-Jae Choi,Seong-Woo Kwak,Byung Kook Kim 한국정보과학회 1997 Journal of Electrical Engineering and Information Vol.2 No.2

This paper proposes a new design method for the PD(Proportional-Derivative)-type FLC(Fuzzy Logic Control). The conventional PD-type FLC is the most general type of the FLC and uses error and change-of-error as input variables of the FLC which are process state variables representing the contents of the rule-antecedent. That is, the conventional PD-type FLC generates control actions according to error and change-of-error. Then the fuzzy rule table is constructed on two-dimensional space of error and change-of-error and commonly has the skew symmetric property. This property allows us to introduce a new variable, which is called a signed distance, and it is used as only an input variable of the FLC. That is, in the proposed PD-type FLC a signed distance is used as the unique input variable of the FLC instead of two variables of error and change-of-error. Then the number of total rules is greatly reduced as well as the control performances are almost the same as the cases of the conventional PD-type FLC. These are showed by computer simulations of two examples.

A Study on a New Design Method of the PD-type Fuzzy Logic Controller

Byung-Jae Choi,Seong-Woo Kwak,Byung Kook Kim 대한전기학회 1997 Journal of Electical Engineering and information S Vol.2 No.2

가토에서 생검총을 이용한 폐생검후 NBCA 충전에 관한 실험적 연구 : 가토폐 생검 후 NBCA 충전

곽병국,정걸호,최치훈,이창준,장희진,심형진 중앙대학교 의과대학 의과학연구소 1999 中央醫大誌 Vol.24 No.1

Pneumothorax and hemorrhage are frequent complications after percutaneous lung biopsy. The purpose of this study is to evaluate the effects of NBCA on plugging the biopsy tract in rabbit lung and pathologic changes caused by NBCA. The right lungs of 14 New Zealand White rabbit were biopsied with an 18G biopsy gun. The biopsy tracts were filled with none(control group) and NBCA mixed with lipiodol(1:1) in 7 rabbits respectively. CT scans were performed immediatoly and 24 hours after procadure. The rabbits were sacrificed and pathologically cvaluated for 17 days. Each pneumothorax and pulmonary heomrrhage as a complication after gun biopsy was seen in 4 cases (57.1%) of the control group(n=7). In NBCA group(n=7), pneumothorax was seen in 2 cases(28.6%) and hemorrhage was seen in 1 case(14.3%)(p>0.05). NBCA filled the biopsy tract and pleural space, and pleural adhesion was seen in 1 case of 2 rabbits complicated by pneumothorax. Pathologically the hemorrhage was more significant in control group(100%) than in NBCA group(28.6%). But the inflammation was 28.6% in control group and 100% in NBCA group. The necrosis, foreign body reaction and fibrosis were similar in both groups. In conclusion, NBCA would be helpful to prevent the pneumothorax and hemorrhage after a percutaneous lung biopsy.

Design of a Sliding Mode Controller with Self-tuning Boundary Layer

Byung-Jae Choi(최병재),Seong-Woo Kwak(곽성우),Byung Kook Kim(김병국) 한국지능시스템학회 1996 한국지능시스템학회논문지 Vol.6 No.2

Design of a SMC-type FLC and Its Equivalence

Byung-Jae Choi(최병재),Seong-Woo Kwak(곽성우),Byung Kook Kim(김병국) 한국지능시스템학회 1997 한국지능시스템학회논문지 Vol.7 No.5