규소화 PU/POSS 나노섬유 매트의 물성

서해천,강영식,최경은,오태환,길명섭,Seo, Hae-Cheon,Kang, Young-Sic,Choi, Kyung-Eun,Oh, Tae-Hwan,Khil, Myung-Seob 한국섬유공학회 2010 한국섬유공학회지 Vol.47 No.6

A polyhedral oligomeric silsesquioxane (POSS) macromonomer with the cage structure of $Si_8O_{12}$ consists of an inorganic silicon and oxygen core surrounded by organic groups on the corners. In this study, POSS was blended with polyurethane and electrospun to produce organic/inorganic hybrid nanofibrous mats. Silica was formed on the nanofibers after exposing the nanofibrous mats to silicic acid under ambient conditions. Structural characterization was analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The morphological difference resulted from the condition of water evaporation and the hybrid with and without the POSS after silicification. The thermal behavior was examined by thermogravimetric analysis (TGA). These 3D inorganic-organic hybrids have potential applications as templates for photonic materials, novel membranes, and scaffolds for hard tissue.

각종 간 질환에 있어서 HBV 표지들 ( Markers ) 의 변동에 관한 관찰

최하진(Ha Jin Choi),김동민(Dong Min Kim),오형석(Hyung Seok Oh),최경해(Kyung Hae Choi),김을수(Eul Soo Kim),정정명(Jung Myung Jung) 대한소화기학회 1987 대한소화기학회지 Vol.19 No.1

N/A In 17 cases of acute hepatitis, 20 cases of chronic active hepatitis, 4 cases of chronic persistent heptatitis, 36 cases of liver cirrhosis, and 26 cases of primary hepatocellular carcinoma who were admitted to the department of internal medicine, Inje medical college, Busan Paik Hospital, we examined the changing patterns of 5 HBV markers (i, e., HBsAg, anti-HBs, anti-HBc, HBeAg, anti-HBe) from January 1982 to May 1985. HBsAg and anti-HBs were examined for 10 months, and HBeAg and anti-Hbe for 8 months in cases of acute hepatitis. In chronic active hepatitis, HBsAg and anti-HBs, and HBeAg and anti-HBe were examined for 24 months, in chronic persistent hepatitis for 12 months, and in 7 cases of liver cirrhosis for 24 months. The serological profile of HBsAg(+)ve anti-HBc(+)ve HBeAg(+)ve was the most prevalent in acute hepatitis(76.5%). In chronic active hepatitis, the most prevalent profiles were HBsAg(+)ve anti-HBc(+)ve HBeAg(+)ve and HBsAg(+)ve anti-HBc(+)ve anti-HBe(+)ve (40% each), and the similar profiles as those of chronic active hepatitis were observed in liver cirrhosis, which were the most prevalent in liver cirrhosis (22.2% each). In primary hepatocellular carcinoma, the most prevalant profile was HBsAg(+)ve anti-HBc(+)ve anti-Hbe(+)ve (34.6%). With serial checks of HBV markers in 15 cases of acute hepatitis who exhibited positive HBsAg initially, 5 cases lost HBsAg, of which one case seroconverted to positive anti-HBs. Among 3 cases with positive HBsAg and HBeAg, one lost HBeAg 1.5 months later and other one 3 months later who regained the positivity for HBeAg 4.5 months later. There was no change of HBsAg and anti-HBs in 20 cases of chronic active hepatitis (17 cases with positive HBsAg, one case with negative HBsAg and anti-HBs, and two cases with positive anti-HBs) for 24 months. Among 8 cases of chronic active hepatitis with positive HBsAg and HBeAg, one case seroconverted to positive anti-HBe 2 months later and other one case lost HBeAg 3 months later (the annual rate of disappearance of HBeAg is 12.5% and that of seroconversion to anti-HBe is 6.3%). Between 2 cases of chronic persistent hepatitis with positive HBsAg and HBeAg, one case seroconverted to positive anti-HBs and anti-Hbe in 12 months. All of 4 cases of liver cirrhosis with positive HBsAg lost HBsAg, and only one of them seroconvert- ed to positive anti-HBs in 24 months. All of 3 cases of liver cirrhosis with positive anti-HBs lost anti-HBs during the same period. Among 4 cases of liver cirhosis with positive HBsAg, one case with positive HBeAg seroconverted to positive anti-HBe, other 2 cases with negative HBeAg and anti-HBe seroconverted to positive anti-Hbe and positive HBeAg respectively, and the other one with positive anti-HBe lost anti-HBe.

졸음운전자의 각성을 위한 햅틱 경고신호의 설계 및 평가

김상호(Sang Ho Kim),예진해(Jin Hae Yae),신종규(Jong Gyu Shin),최경임(Kyung Im Choi) 대한인간공학회 2018 大韓人間工學會誌 Vol.37 No.3

Objective: This study is to design optimal haptic warning signal to secure awareness of drowsy driver and evaluate its alertness compared with the auditory signal. Background: As drowsy driving is one of the causes of fatal traffic accidents, the vehicle needs an assistant system that can monitor the driver"s drowsiness and give warnings to arouse in case of drowsy driving. It is important to design and utilize effective warning signals in a drowsy driving warning system (DDWS) for fast and clear response of the driver. Under certain circumstances like public transportations, haptic display is more appropriate for silent and private communication between the system and the driver. Method: Experiments were conducted to evaluate alertness of warning signals in terms of response rate and time in a simulated driving environment. Subjects participated in the experiments for comparing the alertness for 3 haptic signals with 1 auditory signal. Different haptic signals modulated by its frequencies of 2, 5, and 8Hz were given in random order when a valid DDWS identified the subjects" drowsiness defined in two levels (light and heavy). Results: The response rate of the haptic signals (90%) was significantly lower than that of the auditory signal (97%) under light drowsy condition, but haptic signal of 2Hz got fastest response time (1,390msec) among the signals. The difference in the response time was statistically significant among the haptic signals but it is not for auditory signal. The response time of 2Hz haptic signal was found as competitive in heavy drowsy condition. Conclusion: It is found that haptic signals with different design parameters can make differences in alertness of drowsy driver and in case of this study the best option was of 2Hz. Application: The Haptic signal is going to be implemented in a DDWS and tested for its alertness in real vehicle conditions.

Candida Albicans 와 Carcinogen 의 경구투여에 의한 Mouse 의 위점막 변화

정정명(Jung Myung Jung),김을수(Eul Soo Kim),오형석(Hyung Seok Oh),최경해(Kyung Hae Choi),이부경(Boo Kyung Lee),설상영(Sang Yung Sul),최하진(Ha Jin Choi) 대한내과학회 1988 대한내과학회지 Vol.34 No.4

N/A 1) In the group of the subject mice administered with candida albicans only, all of 6 mice had an inflammatory change both in stomach antrum and body at the 1 month-interval check. At the 3 month interval check, an inflammation in stomach antrum occurred in all of 6 mice; however, in stomach body 5 mice had an inflammation and 1 mice a mocosal atrophy, At the 6 month-interval check, all of 8 mice had an inflammatory change in stomach antrum, while 4 of them got a mucosal atrophy in stomach body. 2) In the group of the mice with a carcinogen alone administered, 2 of 4 mice in the 6 month-group, and 5 of 8 mice in the 9 month-group revealed a mucosal dysplasia with no appearance of cancer. But the degree of dysplasia was one mouse in grade A and another one mouse in grade B, respectively, at the 6 month-interval check, while 2 mice in grade B, and 3 mice in grade C, respectively, at the 9 month-interval check. 3) In the group of mice administered both with carcinogen and candida albicans, 2 of 4 mice showed no cancer but mucosal dysplasia of grade B at the 6 month-interval check, while at the 9 month-interval check, 6 of 8 mice had a squamous cell cancer (especially 3 having been grossly examined) and the other two had mucosal dysplasia of grade C. 4) The findings in the liver tissue of the mice adminstered with the carcinogen for more than 8 months revealed a severe liver cell dysplasia with no evidence of hepatoma. 5) The results from this experimental study suggested that in case of provoking a stomach cancer due to a carcinogen administered in the mice, gastrointestinal infection of pathogenic organism such as candida does play a promoting role. However, whether a suggestion from this experimental study will be applicable to human beings as well or not will have to await a lot of further researches thereafter in the field, There have been reported many experimental researches on the oncogenic effects of various nitroso-compounds since Barnes and Magee, in 1956, concluded the acute hepatotoxicity and oncogenic action of dimethylnitrosamine in a number of experimental animals. Thereafter these nitroso-compounds have been assumed to be an environmental carcinogen in human beings as well as a potent carcinogen in animals. Much attention has been paid particulary on the relation of stomach cancer and nitrosamine since the nitrosamine synthesis in human gastric juice was known to be available. However. at present, it seems so hard to confirm nitrosamine as a vital factor of human cancer that far more information is demanded to identify it accurately. Recent reports, including ours, show a high frequency of candida albicans infection in gastrointestinal tract by various environmental factors. But the influence of candida multiplication on gastric ulcer or stomach cancer has scarcely been known. In this research we made a study of possible effects of candida infection on the gastric mucosa injury as well as on stomach cancer.