• 한국도로학회논문집
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• 제14권6호
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• pp.131-138
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• 2012

PURPOSES : Two-lane highways have one lane in each direction, and lane changing and passing maneuvers take place in the opposing lane depending on the availability of passing sight distance. 2001 Korea Highway Capacity Manual (KHCM) is classified into two classes of two-lane highways (Type I, II), and average travel speed and time-delayed rate are used as measures of effectiveness (MOEs). However, since existing two-lane highways have both uninterrupted and interrupted traffic flow-system elements, a variety of free-flow speeds exhibits in two-lane highways. In addition, it is necessary to check if the linear-relationship between volumes and time-delayed rate is appropriate. Then, this study is to reestablish the relationship between average travel speed, time-delayed rate, and flow. METHODS : TWOPAS model was selected to conduct this study, and the free-flow speeds of passenger cars and the percentage of following vehicles observed in two-lane highways were applied to the model as the input. The revised relationships were developed from the computer simulation. RESULTS : In the revised average travel speed vs. flow relationship, the free-flow speed of 90km/h and 70km/h were added. It shows that the relationship between time delayed-rate and flow appeared to be appropriate with the log-function form and that there was no difference in time-delayed rate between the free flow speeds. In addition to revise the relationships, the speed prediction model and the time-delayed rate prediction model were also developed. CONCLUSIONS : The revised relationships between average travel speed, time-delayed rate, and flow would be useful in estimating the Level of Service(LOS) of a two-lane highway.

• Archives of Plastic Surgery
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• 제45권1호
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• pp.51-57
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• 2018

Background The free anterolateral thigh (ALT) flap has been widely used for various kinds of reconstructions. However, delayed healing at the donor site occasionally occurs due to wound dehiscence or the partial loss of grafted skin at the donor site. The aim of the present study was to identify reliable predictive factors for delayed healing at the donor site after the harvest of a free ALT flap. Methods This study included 52 patients who underwent reconstructive procedures using free ALT flaps. The delayed healing group included patients with wounds at the donor site that had not healed over 3 weeks after surgery, and the normal healing group included patients who showed wound healing within 3 weeks after surgery. Multivariate logistic regression models were created to identify the risk factors for delayed healing at the ALT flap donor site. Results Among the 52 patients, 24 (46.2%) showed delayed healing at the donor site, and 6 patients required additional operative treatment. A high preoperative body mass index (BMI), smoking, and skin grafting were found to be significantly associated with delayed healing at the ALT donor site. Of the 37 patients who underwent skin grafting, 23 (62%) experienced delayed healing at the donor site. Conclusions A high preoperative BMI, smoking, and skin grafting were risk factors for delayed healing at the free ALT donor site. Skin grafting at the ALT donor site should be avoided in patients with a high BMI or a habit of smoking.

• 한국임상약학회지
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• 제29권2호
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• pp.101-108
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• 2019

Background: High doses of methotrexate (MTX) are often used in various chemotherapy protocols to treat acute lymphoblastic leukemia (ALL) and non-Hodgkin's lymphoma (NHL) in children, but its delayed elimination increases the occurrence of adverse events, such as bone marrow suppression. The aim of this study was to investigate the elimination of MTX at 24 and 48 hours. Methods: We retrospectively analyzed electronic medical records of ALL or NHL pediatric patients who received $5g/m^2$ MTX infusion over 24 hours (between June, 2012 and July, 2018) at the Yonsei University Health System, Korea. The delayed elimination of MTX concentrations was assessed with 100 or $150{\mu}M$ MTX at 24 hours, and 2 or $5{\mu}M$ at 48 hours. Results: Among the 85 MTX cycles administered, 23 cycles were classified in delayed elimination group, and 62 cycles showed normal elimination. At 24 hours, the delayed elimination group with MTX concentration > $100{\mu}M$ showed higher percentage than group with MTX concentration < $100{\mu}M$ (45.8% vs. 19.7%, p = 0.015). However, no differences were observed at $150{\mu}M$ MTX (p = 0.66). At 48 hours, the delayed elimination was higher than the normal elimination at both concentration baselines (p < 0.001 at $2{\mu}M$, p = 0.024 at $5{\mu}M$). Conclusions: MTX concentrations greater than $100{\mu}M$ show high probability of delayed elimination at 24 hours. When MTX levels are above normal, leucovorin and hydration regimens should be continued to prevent delayed elimination.

• Archives of Plastic Surgery
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• 제51권1호
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• pp.20-26
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• 2024

The etiology and pathophysiology of delayed inflammatory reactions caused by hyaluronic acid fillers have not yet been elucidated. Previous studies have suggested that the etiology can be attributed to the hyaluronic acid filler itself, patient's immunological status, infection, and injection technique. Hyaluronic acid fillers are composed of high-molecular weight hyaluronic acids that are chemically cross-linked using substances such as 1,4-butanediol diglycidyl ether (BDDE). The mechanism by which BDDE cross-links the two hyaluronic acid disaccharides is still unclear and it may exist as a fully reacted cross-linker, pendant cross-linker, deactivated cross-linker, and residual cross-linker. The hyaluronic acid filler also contains impurities such as silicone oil and aluminum during the manufacturing process. Impurities can induce a foreign body reaction when the hyaluronic acid filler is injected into the body. Aseptic hyaluronic acid filler injections should be performed while considering the possibility of biofilm formation or delayed inflammatory reaction. Delayed inflammatory reactions tend to occur when patients experience flu-like illnesses; thus, the patient's immunological status plays an important role in delayed inflammatory reactions. Large-bolus hyaluronic acid filler injections can induce foreign body reactions and carry a relatively high risk of granuloma formation.

• 대한소아치과학회지
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• 제44권1호
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• pp.56-63
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• 2017

국소적, 전신적 요인을 동반하지 않는 제1대구치의 맹출 지연은 해당 치아의 발육 지연을 동반한다. 본 연구의 목적은 제1대구치의 발육지연의 임상적 양상 및 동반하는 다른 치아의 발달 이상에 관하여 고찰하는 것이다. 국소적 요인이 없이 제1대구치 맹출 지연을 보이는 건강한 어린이 40명의 파노라마방사선 사진 분석을 시행하였다. 2명의 평가자가 Nolla 방법을 이용하여 해당 치아의 발육지연 여부, 해당 분악의 제2대구치 발육 이상 여부 및 제3대구치를 제외한 다른 치아의 선천적 결손 여부에 관하여 조사하였다. 제1대구치의 발육지연은 상악에서 호발하였고, 여성에게서 양측성 이환, 남성에게서 편측성 이환이 많이 관찰되었다. 제1대구치의 발육지연이 있는 환아는 유의하게 높은 선천적 결손치의 유병률을 보였으며, 이환된 분악의 제2대구치는 모두 발육 지연 혹은 선천적 결손의 이상을 보였다. 본 연구결과 제1대구치의 발육지연은 다른 치아의 선천적 결손과 밀접한 연관이 있는 것으로 나타났다.

• 대한소아치과학회지
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• 제21권2호
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• pp.555-560
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• 1994

Among the permanent teeth. the first permanent molars play the greatest role in occlusion and function. So, the congenital missing, abnormal reuption or abnormal formation of the first permanent molars in the course of arch development would inflict normal development of dental arches. Therefore, early detection of abnormal cases related to first permanent molars and understanding of current and predictable clinical problems are essential for proper occlusal guidance in children. With the aim of investigating the clinical patterns of delayed eruption of first permanent molars in children, panoramic tomograms of the childern in mixed and early permanent dentition were observed and analyzed. The results were as follows: 1. Among the delayed eruption of first permanent molars, on tooth or bilateral teeths were affected most frequently. Delayed eruption was more prevalent in maxilla than in mandible. 2. The formation of tardily erupted teeth were also delayed. 3. Delayed eruption was generally limited in first molars or molar segments. 4. Delayed eruption of first permanent molars is accompanied by abnormal position of tooth germs, for example, ectopic eruption, delayed dental age, delayed localized tooth formation and generalized congenital missing. 5. There was a tendency of delayed formation or congenital missing of second molars distal to tardily erupted 1st molars. And that was more marked in maxilla than in mandible. 6. There was reported that affected 1st molars show various size and shapes. Maxillary 1st molars showing delayed eruption showed a tendency of having 3 cusps. But, tardily erupted mandibular 1st molars showed no significant reduction in mesiodistal dimension, as reported. 7. In some cases, the delayed eruption of 1st permanent molars was associated with ectopic eruption, but their formation was not usually retarded. 8. In skeletal class III cases, there showed a tendency of mandibular 1st molars to erupt earlier than maxillary 1st molars with greater interval than in normal occlusion.

• 대한수학회보
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• 제48권2호
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• pp.325-334
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• 2011

In this paper we consider the discrete time delayed renewal risk model. We investigate what will happen when the distribution function of the discounted proper deficit is asymptotic in the initial surplus. In doing this we establish several lemmas regarding some related ruin quantities in the discrete time delayed renewal risk model, which are of significance on their own right.

• 대한수학회보
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• 제53권3호
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• pp.793-819
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• 2016

In this paper, we establish the existence and uniqueness of the solution for a class of reflected backward stochastic differential equations with time delayed generator (RBSDEs with time delayed generator, in short) in the case when the terminal value and the obstacle process are $L^p$-integrable with p ${\in}$]1, 2[ for a sufficiently small Lipschitz constant of the generator and the time horizon T.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.909-912
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• 1988

This paper proposed the new control law which is defined by instantaneous output and time delayed output. To analyze the system with time delayed output, the way which transforms output time delayed systems into instantaneous output systems is presented. The output responses were more improved by the new control law then that of the instantaneous output control law. The algorithm for simulation and a numerical example are presented.

• Journal of Korean Neurosurgical Society
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• 제29권4호
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• pp.536-542
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• 2000

Objective : This study was performed to evaluate the relationships among intracranial pressure(ICP), cerebral perfusion pressure(CPP), and cerebral arteriovenous oxygen difference($AVDO_2$) which were used as parameters of adequacy of cerebral blood flow to support cerebral metabolism after severe head injury and also to examine the association between delayed cerebral infarction and outcome. Material and Method : The authors studied the ICP, CPP and $AVDO_2$ before and after treatment on 34 head-injured patients from June 1996 to December 1997 and examined the association with the change of an ICP, CPP and $AVDO_2$ following treatment and the development of delayed cerebral infarction. Sixteen patients underwent craniotomy for hematoma evacuation and eighteen patients received mannitol to decrease ICP. Results : The development of delayed cerebral infarction was demonstrated in 3(42.9%) out of 7 patients in no improvement group and 13(48.1%) out of 27 patients in improvement group with an increased ICP following treatment. Also, the development of delayed cerebral infarction was demonstrated in 8(50%) out of 16 patients in no improvement group and 8(44.4%) out of 18 patients in improvement group with a decreased CPP following treatment. The association with changes of ICP and CPP following treatment and development of delayed cerebral infarction was not statistically significant(p>0.01). However, 11(78.6%) out of 14 patients who demonstrated an increase in $AVDO_2$ and 5(25%) out of 20 patients who demonstrated a decrease in $AVDO_2$ following treatment developed delayed cerebral infarction. No improvement(reduction) in $AVDO_2$ following treatment was significantly associated with the development of delayed cerebral infarction(p<0.01). All of 16 patients with delayed cerebral infarction showed poor prognosis. Conlcusion : The change of $AVDO_2$ rather than those of ICP and CPP was considered more important factor for the development of the delayed cerebral infarction and poor outcome.