• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제27권5호
• /
• pp.403-414
• /
• 2005

The purpose of this study was to identify the effectiveness of the modified distraction osteogenesis (DO) method with the concept of overdistraction and compression stimulation which have been previously suggested by the authors in 2002 and to explore the optimal distraction-compression ratio and appropriate latency period for the compression force application during consolidation. The experimental specimens were assessed with radiography, histologic findings, and dual energy x-ray absorptiometry (DEXA) after the conventional DO method and the modified DO technique had been applied on rat mandibles. Total 60 rats were used for the study. In experimental group of 54 adult rats, mandibular osteotomies between the first and second molar areas were performed and customized external distractors were applied. The surgeries on 6 rats of control group also were done with same osteotomy technique and DO device application. Final amount of distraction was set-up as 2 mm on both groups. But, in a experimental group of 54 rats, distraction osteogenesis with a compression force were performed with the different distraction-compression ratio and variant latency periods for compression. The three ratio-subgroups were made as distraction 4 mm group with compression 2 mm, distraction 3 mm group with compression 1 mm, and distraction 2.5 mm group with compression 0.5 mm. In addition, The three subgroups with 3, 7, 11 days latency period prior compression were allocated on each ratio-subgroups. Total 9 subgroups consisted of 6 rats on each subgroup. In control group of 6 rats, conventional distraction technique were routinely performed. The rats of control groups were sacrificed on postoperative 3, 6 weeks after 2 mm distraction. The rats in the experimental groups also were sacrificed on the same euthanasia days of control groups to compare the wound healing. Final available specimens were 55 rats except 5 due to osteomyelitis, device dislodgement. Distraction-compression combined group on 6 weeks generally had showed increased bone mineral density than the same period group of conventional distraction technique on the DEXA study. More matured lamellar bone state and extended trabecular pattern in the combined group than those of control group were also observed in the histologic findings on 6 weeks. In the distraction-compression combined groups, the bone density of 2.5 mm distraction subgroups with 0.5 mm compression showed the highest value on the DEXA study among various force ratio groups. In the distraction-compression combined groups, the bone density of 3 day latency period subgroups showed the highest value on the DEXA study among various latency period groups for the compression application. From this study, we could deduce that 1/5 force ratio for the compression versus distraction, 3 day latency period prior compression application would be the most effective condition if modified distraction osteogenesis technique might be applicable. The modified DO method with a compression force may improve the quality of bone regenerate and shorten total treatment period in comparison with conventional DO technique clinically.

• Safety and Health at Work
• /
• 제1권2호
• /
• pp.140-148
• /
• 2010

Objectives: Determining the work-relatedness of lung cancer developed through occupational exposures is very difficult. Aims of the present study are to develop a decision tree of occupational lung cancer. Methods: 153 cases of lung cancer surveyed by the Occupational Safety and Health Research Institute (OSHRI) from 1992-2007 were included. The target variable was whether the case was approved as work-related lung cancer, and independent variables were age, sex, pack-years of smoking, histological type, type of industry, latency, working period and exposure material in the workplace. The Classification and Regression Test (CART) model was used in searching for predictors of occupational lung cancer. Results: In the CART model, the best predictor was exposure to known lung carcinogens. The second best predictor was 8.6 years or higher latency and the third best predictor was smoking history of less than 11.25 pack-years. The CART model must be used sparingly in deciding the work-relatedness of lung cancer because it is not absolute. Conclusion: We found that exposure to lung carcinogens, latency and smoking history were predictive factors of approval for occupational lung cancer. Further studies for work-relatedness of occupational disease are needed.

• 정보보호학회논문지
• /
• 제14권1호
• /
• pp.79-89
• /
• 2004

Mobile IP Low Lattency Handoffs Mobile IP 등록 요청 절차를 처리하는데 발생하는 지연을 최소화시켜 실시간 서비스를 가능하게 해준다. 그러나 인증, 권한 검증, 과금을 지원하는 AAA 기반의 Mobile IP 망에서는 매 지역등록이 일어날 때마다 새로운 세션 및 세션 키가 필요하며. 이를 위해 홈 망까지 등록 절차가 수행되어야 한다. 이로 인해, 이동 노드 재인증 절차와 방문 망에서 홈 망까지의 트랜잭션으로 인한 통신 지연이 발생한다. 이러한 지연을 줄이기 위해서 본 논문에서는 홈 망의 AAA 서버를 관여시키지 않고, 이전에 할당된 세션 키론 재사용 하여 Low Latency Handoffs를 수행하는 기법을 제안한다. 이 기법에서는 이전 방문 에이전트와 새로운 방문 에이전트가 세션 키를 교환하는 단계에서 발생하는 보안 취약점을 해결하기 위하여 게이트웨이 방문 에이전트로 하여금 신뢰할 수 있는 제3자 역할을 수행하도록 하고 이를 통해 키를 공유한다. 제안한 기법에 의하면 홈 망까지의 트랜잭션이 필요 없고, 세션 키의 기밀성과 무결성이 보장되므로 이동 노드가 빠르고 안전하게 핸드오프를 수행할 수 있다.

• Annals of Clinical Neurophysiology
• /
• 제3권1호
• /
• pp.15-20
• /
• 2001

Background : Carpal tunnel syndrome(CTS) is the most common entrapment neuropathy that refers to a group of signs and symptoms resulting from compression of the median nerve at the wrist. The course of CTS in older patients is different from the younger patients. This difference may be the result of different underlying mechanisms. The different nerve conduction studies of CTS may signify different approaches in management. This study was done to assess the differences in nerve conduction study of CTS in younger and older patients. Methods : This study involved 224 patients who visited Gachon Medical School, Gil Medical Center and was diagnosed by nerve conduction study from October 1997 to October 1999. We compared the results of nerve conduction study to age, especially in between those under 60 years and those 60 years or over CTS patients. Nerve conduction study consists of motor studies of both median nerves(terminal latency, compound action potential) and sensory studies(nerve conduction velocity, nerve action potential). And we also evaluated the variables between younger and older patients group. Those variables include sex, symptom period, laterality, abnormal physical findings and radiculopathy. Results : We found that a significant increase of terminal latency(p<0.1), but a decrease in compound motor action potential(p<0.05) in older patient's group. There was no significant differences in sensory nerve conduction velocity and action potential between those under 60 years and those 60 years or even patients. And also there was no significant difference in sex, symptom period, laterality, abnormal physical findings, radiculopathy between older and younger patients. Conclusions : This study showed a significant increase in the terminal latency and a decrease in compound action potential in older patients. The different nerve conduction studies of CTS by age effect may need different approaches in management.

• 대한의용생체공학회:의공학회지
• /
• 제30권4호
• /
• pp.306-310
• /
• 2009

The purpose of this study is to observe the change in gamma-band cortical activities (GBAs) due to task difficulty. Event-related potential and gamma-band activity were investigated using electroencephalograms recorded during auditory oddball tasks with two difficulty levels. For more difficult task, the amplitude of P300 decreased and the peak latency of P300 was delayed significantly compared to easier task. The induced GBA decreased considerably during the P300 latency period and the peak latency of the induced GBA was delayed for more difficult task. The results imply that the difficulty-related change in cortical information processing may be implemented as a change in the strength of local neuronal association.

• 수면정신생리
• /
• 제5권2호
• /
• pp.202-209
• /
• 1998

Authors report the findings of nocturnal polysomnography and multiple sleep latency test(MSLT) before and after morning light treatment in a winter depressive patient with hypersomnia. On polysomnographic recordings, the sleep pattern of this case before light treatment was similar to that of narcolepsy exhibited, sleep onset REM period(SOREMP). After treatment, the shortened REM latency changed to normal condition, but, deep sleep percentage did not changed, and stage 4 sleep percentage was decreased. Depressive symptoms were improved on clinical interview with Hamilton Depressive Rating Scale. Sleep log showed shortened sleep latency and reduced sleep duration. These findings suggest that although light treatment could alter the sleep structure in seasonal affective disorder with hypersomnia, it does not necessarily imply that antidepressant response of light treatment is result of change of sleep structure.

• The Korean Journal of Physiology
• /
• 제23권1호
• /
• pp.139-149
• /
• 1989

Although tail flick reflex (TFR) in rats has been used as a classic model of the nociceptive test to evaluate the action of analgesics, there have been few studies on the origin of the latent period of TFR. Present study was performed to elucidate the mechanism of increase in latency of TFR by morphine in anesthetized rats. Tail skin and dorsolateral tail nerve were stimulated electrically and EMG activities were recorded from abductor caudae dorsalis muscle participating in tail flick reflex. In the case of noxious radiant heat stimulation to tail, the tail flick tension was recorded before and after administration of morphine. Then changes in latency and conduction velocity of peripheral nerve were evaluated. The results obtained were as follows: 1) The latencies of TFR evoked by the electrical stimulation of tail skin and dorsolateral tail nerve were all within 40 ms and were elongated by several milliseconds from control after the administration of morphine. Peripheral conduction velocities of tail flick afferent nerve were within the range of 10-25 m/s. 2) The conduction velocity of peripheral nerve was significantly reduced after morphine administration, therefore the afferent time (utilization time+conduction time to spinal cord) was significantly increased. But the time for central delay and efferent time was not affected by morphine. 3) The conduction velocity under room temperature $(20-25^{\circ}C)$ was significantly reduced after morphine while that under vasodilation state $(40{\sim}42^{\circ}C)$ increased, 30 min and 45 min after morphine. The conduction velocity under vasodilation state without treatment of morphine increased continuously 4) The latency in tension response of TFR evoked by electrical stimulation was elongated by several milliseconds from control while the latency evoked by noxious radiant heat was elongated by several seconds compared with that of control. From the above results, it could be concluded that: 1) the increased latency of TFR evoked by electrical stimulation of the tail after morphine administration was due to the reducton in conduction velocity of peripheral nerve, which was the secondry effect of morphine on the peripheral vasomotion and 2) increased latency of TFR evoked by noxious radiant heat was also due to the same effect of morphine and the increase in cutaneous insulation to the noxious heat.

• 자원ㆍ환경경제연구
• /
• 제12권1호
• /
• pp.49-74
• /
• 2003

This study used a slightly modified version of contingent valuation questionnaire designed and developed by Krupnick et al.(2000) to estimate the value of mortality risk reduction for environmental policy. Because that environmental policy, especially air pollution policy with some latency main effect on mortality risk reduction of old people with some latency period, respondents were asked about their current WTP for 5/1,000 mortality risk reduction being to take place beginning at 70 over the course of ten years. The annual mean WTP is 233,370 won (standard error 32,570 won) in spike/continuous/interval data model. The implied VSL is 466 million won. The 95% confidence interval is 339 million won~594 million won.

• The Korean Journal of Physiology
• /
• 제8권1호
• /
• pp.15-22
• /
• 1974

The influence, upon male rat's mating behavior, of Korean Panax Ginseng administered for 3 and 5 days was investigated by direct behavioral observation and also by counting the number of copulation plugs the animals deposited. Four쇼-four male albino rats were used. Part of the animals received ginseng for 3 days (ginseng-3 day group, N= 12) or for 5 days(ginseng-5 day group, H=10), while the remaining animals received saline for 3 days (saline-3 day group, N=12) or for 5 days (saline-S day group, N=10). Each animal belonging to the 2 ginseng groups received subcutaneously 0.5 ml/100 g body weight of ginseng alcohol extract solution (4 mg of the ethyl alcohol extract in 1 ml of physiological saline), and each rat belonging to the 2 saline groups received the same amount of saline per day. During the dark period of the light-dark cycle on the next day following the last drug administration, a female rat in the artificial estrus was introduced to each male and the mating behavior was observed for 45 minutes. The observation session was divided into two parts and, in the early part which terminated with the first ejaculation and succeeding intromission, following behavioral measures were taken: mounting latency, intromission latency, inter-intromission period, ejaculatory latency(time from the first intromission until the first ejaculation), occurrence of mounting with intromission, occurrence of mounting without intromission, and postejaculatory interval. Behavioral measures taken in the later part of the session after the first ejaculation were: occurrence of mounting with intromission, occurrence of mounting without intromission, and occurrence of ejaculation. Immediately after the behavioral observation session the experiment turned to measure, for 10 days, the number of copulation plug which each pair of rats deposited. Following results were obtained: 1. After several mountings mounting with intromission, males of the 2 ginseng groups finished the first ejaculation significantly earlier than the corresponding 2 saline groups did. 2. The postejaculatory latency was significantly reduced in the ginseng-5 day group compare with the value of the saline-5 day group and also compared with the value of the ginseng-3 day group. 3. The 2 ginseng groups ejaculated significantly more often in 45 minutes' observation session than the corresponding 2 saline groups did. 4. The number of copulation plug deposited in 10 days by the animals of the 2 ginseng groups. significantly exceeded the number deposited by the corresponding 2 saline group animals. The animals of the ginseng-5 day group deposited copulation plugs significantly more than the animals of the ginseng-3 day group did. It is inferred from the above results that the ginseng facilitates mating behavior of male rats, and that the degree of facilitation may be influenced by the duration of drug administration.

• 생명과학회지
• /
• 제19권3호
• /
• pp.403-410
• /
• 2009

본 연구는 청소년기 흰쥐를 대상으로 4주간의 저강도 트레드밀 운동이 기억력과 해마 신경세포생성, BDNF, Trkb, 중격 콜린세포에 미치는 효과를 조사하기 위하여 수행되었다. 먼저 운동이 기억력에 미치는 효과를 step-through avoidance에서 검사한 결과 운동을 실시했던 흰쥐의 retention latency가 대조군에 비해 유의하게 증가되어 기억력 향상을 나타내었다. 이후 기억력 향상기전으로 해마에서 신경세포증식과 BDNF 및 TrkB 단백질 발현을 정량화 한 결과에서도 운동군의 신경세포 생성율과 BDNF와 TrkB 단백질 발현 모두 대조군에 비해 유의하게 증가된 것으로 나타났다. 게다가 운동을 통한 전뇌 콜린세포 수의 증가가 해마 신경세포생성과 BDNF 발현 증가에 기여하는 것으로 나타났다. 이러한 결과는 청소년기 운동이 기억력 향상에 도움이 될 수 있음을 보여주는 것이다.