• The Journal of Korean Academy of Prosthodontics
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• v.46 no.3
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• pp.255-260
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• 2008

STATEMENT OF PROBLEM: Preparation of implant beds with lasers is considered a safe and reliable method, but the accuracy of this technique has not been examined. PURPOSE: The purpose of this study was to evaluate the accuracy and effectiveness of implant bed preparation using an Er,Cr:YSGG laser. MATERIAL AND METHODS: An Er,Cr:YSGG laser was applied to pig rib bone. The laser was employed at a 5.75 W power setting, 30 Hz/sec pulse repetition, and 70 ${\mu}s$ pulse duration with 50 % water and 60% air spray. According to laser tips the groups were divided as follows; Group 1: paralleled - shaped sapphire tip (0.6 mm${\Phi}$), Group 2: paralleled - shaped zirconia tip (0.6 mm${\Phi}$), Group 3: tapered sapphire tip (0.4 mm${\Phi}$). The Er,Cr:YSGG laser tip was separated by 1 mm from the bone and applied for 15 seconds in a non-contact mode. After the application, the bone was sectioned for specimens. Histologic measurements were determined by computerized morphometry. The length of the prepared bone surface was measured and the width of the entrance was measured. The results were analyzed with one-way ANOVA (P<0.05). RESULTS: The prepared length of group 3 was longer than that of group 2. The prepared bone width was larger than the width of the laser tip in every group. Additional bone removal was observed adjacent to the prepared area and displayed an irregular surface. CONCLUSION & DISCUSSION: Different cutting effects were observed according to the laser tip, emphasizing the importance of proper tip selection in the clinical setting. This preliminary study supported the existence of hydrokinetic effects.

• The Korean Journal of Nuclear Medicine
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• v.27 no.2
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• pp.309-314
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• 1993

We report a case of 33-year-old man with a transient splenic uptake who had traumatic multiple rib fractures and hernoperitoneum combined with underlying liver cirrhosis, liver cirrhosis with liver bed laceration and splenomegaly without any other demonstrable splenic lesion due to traffic accident was found by abdominal ultrasound and surgery. Incidentally, $^{99m}Tc$-MDP Bone scan showed whole prominent splenic uptake, spleen was also visible on $^{99m}Tc$ Tin colloid liver scan. We suggest the splenic uptake of the radionuclide temporary splenic infarct to the transient total splenic infarction or unknown traumatic effect.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.2
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• pp.297-304
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• 1997

Morphological and Benetic comparision were studied for the arkshell populations of Korea and China. The shell was collected from commercial arkshell bed in Jinhae Bay, Korea and from an hatchery in Young Seong, China. Shell Parameters, number of radial ribs and random amplified polymorphic DNA (RAPD) band were measured. The two populations had morphological and genetic differences. There was significant morphological difference $(P\leq0.05)$ in the ratio of the longest radial rib to the shell length. Posterior parts of the Chinese arkshell were more elongated than those of the Korean arkshell. Number of radial ribs were $36\~41$ for the Korean arkshell and $39\~43$ for the Chinese arkshell. RAPD markers generated tty each of 19 primers were $2\~6$ bands. Genetic diversity between the two Populations was clear since the genetic similarity was very low, not exceeding 0.29. The genetic similarity among the Korean arkshells $(0.58\~0.40)$ was higher than that of the Chinese arkshells $(0.48\~0.32)$.