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Development of implant loading device for animal study about various loading protocol: a pilot study
Joon-Ho Yoon,Young-Bum Park,Yuna Cho,Chang-Sung Kim,Seong-Ho Choi,Hong-Seok Moon,Keun-Woo Lee,June-Sung Shim 대한치과보철학회 2012 The Journal of Advanced Prosthodontics Vol.4 No.4
PURPOSE. The aims of this pilot study were to introduce implant loading devices designed for animal study and to evaluate the validity of the load transmission ability of the loading devices. MATERIALS AND METHODS. Implant loading devices were specially designed and fabricated with two implant abutments and cast metal bars, and orthodontic expansion screw. In six Beagles, all premolars were extracted and two implants were placed in each side of the mandibles. The loading device was inserted two weeks after the implant placement. According to the loading protocol, the load was applied to the implants with different time and method,simulating early,progressive,and delayed loading. The implants were clinically evaluated and the loading devices were removed and replaced to the master cast, followed by stress-strain analysis. Descriptive statistics of remained strain (με) was evaluated after repeating three cycles of the loading device activation. Statistic analysis was performed using nonparametric, independent t-test with 5% significance level and Friedman's test was also used for verification. RESULTS. The loading devices were in good action. However, four implants in three Beagles showed loss of osseointegration. In stress-strain analysis, loading devices showed similar amount of increase in the remained strain after applying 1-unit load for three times. CONCLUSION. Specialized design of the implant loading device was introduced. The loading device applied similar amount of loads near the implant after each 1-unit loading. However, the direction of the loads was not parallel to the long axis of the implants as predicted before the study.
Cho, Joon,Moon, Chang Taek,Kang, Hyun Seung,Choe, Woo Jin,Chang, Sang Keun,Koh, Young Cho,Roh, Hong Gee The Korean Academy of Medical Sciences 2008 JOURNAL OF KOREAN MEDICAL SCIENCE Vol.23 No.4
<P>Vertebrobasilar junction entrapment due to a clivus fracture is a rare clinical observation. The present case report describes a 54-yr-old man who sustained a major craniofacial injury. The patient displayed a stuporous mental state (Glasgow Coma Scale [GCS]=8) and left hemiparesis (Grade 3). The initial computed tomography (CT) scan revealed a right subdural hemorrhage in the frontotemporal region, with a midline shift and longitudinal clival fracture. A decompressive craniectomy with removal of the hematoma was performed. Two days after surgery, a follow-up CT scan showed cerebellar and brain stem infarction, and a CT angiogram revealed occlusion of the left vertebral artery and entrapment of vertebrobasilar junction by the clival fracture. A decompressive suboccipital craniectomy was performed and the patient gradually recovered. This appears to be a rare case of traumatic vertebrobasilar junction entrapment due to a longitudinal clival fracture, including a cerebellar infarction caused by a left vertebral artery occlusion. A literature review is provided.</P>
Joon-Woo Lee,Sang-Gil Cho,Jun-Hyung Cho,Han-Gyu Kim,Kiho Bae 한국통합생물학회 2005 Animal cells and systems Vol.9 No.3
Most living organisms exhibit the circadian rhythm in their physiology and behavior. Recent identification of several clock genes in mammals has led to the molecular understanding of how these components generate and maintain the circadian rhythm. Many reports have implicated the photic induction of either mPer1 or mPer2 in the hypothalamic region called the suprachiasmatic nucleus (SCN) to phase shift the brain clock. It is now established that peripheral tissues other than the brain also express these clock genes and that the clock machinery in these tissues work in a similar way to the SCN clock. To determine the role of the two canonical clock genes, mPer1 and mPer2, in the peripheral clock shift, stable HEK293EcR cell lines that can be induced and stably express these proteins were prepared. By regulating the expression of these proteins, it could be shown that induction of the clock genes, either mPer1 or mPer2 alone is not sufficient to cause clock phase shifting in these cells. Our real-time PCR analysis on these cells indicates that the induction of mPER proteins dampens the expression of the clock-specific transcription factor mBmal1. Altogether, our present data suggest that mPer1 and mPer2 may not function in clock shift or take part in differential roles on the peripheral circadian clock.
Cho, Kyung Hwa,Lee, Seungwon,Ham, Young Sik,Hwang, Jin Hwan,Cha, Sung Min,Park, Yongeun,Kim, Joon Ha IWA Publishing 2009 Water Science & Technology Vol.59 No.11
<P>The present study proposes a methodology for determining the effective dispersion coefficient based on the field measurements performed in Gwangju (GJ) Creek in South Korea which is environmentally degraded by the artificial interferences such as weirs and culverts. Many previous works determining the dispersion coefficient were limited in application due to the complexity and artificial interferences in natural stream. Therefore, the sequential combination of N-Tank-In-Series (NTIS) model and Advection-Dispersion-Reaction (ADR) model was proposed for evaluating dispersion process in complex stream channel in this study. The series of water quality data were intensively monitored in the field to determine the effective dispersion coefficient of E. coli in rainy day. As a result, the suggested methodology reasonably estimates the dispersion coefficient for GJ Creek with 1.25 m2/s. Also, the sequential combined method provided Number of tank-Velocity-Dispersion coefficient (NVD) curves for convenient evaluation of dispersion coefficient of other rivers or streams. Comparing the previous studies, the present methodology is quite general and simple for determining the effective dispersion coefficients which are applicable for other rivers and streams.</P>