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노화에 따른 아스팔트의 물리화학적 변화와 혼합물 성능에 미치는 영향 연구
이백운,황의윤,Hiroki Hosono,Makoto Hiramatsu 한국도로학회 2020 한국도로학회논문집 Vol.22 No.2
PURPOSES : Asphalt pavements are damaged by various causes, such as cracks, potholes due to climate, and traffic environment. Asphalt aging has a significant effect on cracks, which may also form potholes. The purposes of this study are to estimate the change in asphalt binder and mixture performance and to correlate the physicochemical changes of the asphalt binder and mixture performance with aging. METHODS : The aging process of the asphalt was determined in the laboratory, based on the methods used in previous studies. In terms of consistency (stiffness), crack-resistance performance, moisture susceptibility, SK investigated the binder part, and Shoreki investigated the mixture part depending on the aging time. RESULTS : The consistency (stiffness) and brittleness of both the asphalt binder and mixture tended to increase with aging. In particular, the crack-resistance performance of the asphalt binder (G*sinδ, ductility, and ΔTc) and mixture (flexural fatigue test and Cantabro test) deteriorated because of asphalt aging. Furthermore, the aging mechanisms (oxidation and polymerization) were identified based on the chemical structure analysis. CONCLUSIONS : It is confirmed that the aging affected the chemical composition change and the physical properties of the asphalt. Asphalt pavements are significantly affected by the aging characteristics of the binder. It is concluded that the crack-resistance performance of the mixture decreases with aging due to these physical and chemical changes.
( Takashi Nonaka ),( Yusuke Sekino ),( Hiroshi Iida ),( Eiji Yamada ),( Hidenori Ohkubo ),( Eiji Sakai ),( Takuma Higurashi ),( Kunihiro Hosono ),( Hiroki Endo ),( Tomoko Koide ),( Hirokazu Takahashi 대한소화기기능성질환·운동학회 2013 Journal of Neurogastroenterology and Motility (JNM Vol.19 No.2
The gastrointestinal motility effects of endogenous incretin hormones enhanced by dipeptidyl peptidase-IV (DPP-IV) inhibitors have not yet been sufficiently investigated. The aim of this study was to determine whether single pre-prandial sitagliptin, the DPP-IV inhibitor, administration might have an effect on the rate of liquid gastric emptying using the 13C-acetic acid breath test. Methods Ten healthy male volunteers participated in this randomized, two-way crossover study. The subjects fasted for overnight and were randomly assigned to receive 50 mg sitagliptin 2 hours before ingestion of the liquid test meal (200 kcal per 200 mL, containing 100 mg 13C-acetate) or the test meal alone. Under both conditions, breath samples were collected for 150 minutes following the meal. Liquid gastric emptying was estimated by the values of the following parameters: the time required for 50% emptying of the labeled meal (T1/2), the analog to the scintigraphy lag time for 10% emptying of the labeled meal (Tlag), the gastric emptying coefficient and the regression-estimated constants (β and k), calculated by using the 13CO2 breath excretion curve using the conventional formulae. The parameters between the 2 test conditions were compared statistically. Results No significant differences in the calculated parameters, including T1/2, Tlag, gastric emptying coefficient or β and k, were observed between the 2 test conditions. Conclusions The present study revealed that single-dose sitagliptin intake had no significant influence on the rate of liquid gastric emptying in asymptomatic volunteers.
( Yasunari Sakamoto ),( Yusuke Sekino ),( Eiji Yamada ),( Hidenori Ohkubo ),( Takuma Higurashi ),( Eiji Sakai ),( Hiroshi Iida ),( Kunihiro Hosono ),( Hiroki Endo ),( Takashi Nonaka ),( Tamon Ikeda ) 대한소화기기능성질환·운동학회 2011 Journal of Neurogastroenterology and Motility (JNM Vol.17 No.4
Background/Aims The administration of liquid nutrients to patients is often accompanied by complications such as gastroesophageal reflux. To prevent gastroesophageal reflux, high-viscosity liquid meals are used widely, however, it still remains controversial whether high-viscosity liquid meals have any effect on the rate of gastric emptying. The present study was conducted with the aim of determining whether high-viscosity liquid meals had any effect on the rate of gastric emptying and mosapride might accelerate the rate of gastric emptying of high-viscosity liquid meals. Methods Six healthy male volunteers underwent 3 tests at intervals of > 1 week. After fasting for > 8 hours, each subject received one of three test meals (liquid meal only, high-viscosity liquid meal [liquid meal plus pectin] only, or high-viscosity liquid meal 30 minutes after intake of mosapride). A 13C-acetic acid breath test was performed, which monitored the rate of gastric emptying for 4 hours. Using the Oridion Research Software (β version), breath test parameters were calculated. The study parameters were examined for all the 3 test conditions and compared using the Freidman test. Results Gastric emptying was significantly delayed following intake of a high-viscosity liquid meal alone as compared with a liquid meal alone; however, intake of mosapride prior to a high-viscosity liquid meal was associated with a significantly accelerated rate of gastric emptying as compared with a high-viscosity liquid meal alone. Conclusions This study showed that high-viscosity liquid meals delayed gastric emptying: however, mosapride recovered the delayed rate of gastric emptying by high-viscosity liquid meals. (J Neurogastroenterol Motil 2011;17:395-401)
( Yasunari Sakamoto ),( Shingo Kato ),( Yusuke Sekino ),( Eiji Sakai ),( Takashi Uchiyama ),( Hiroshi Iida ),( Kunihiro Hosono ),( Hiroki Endo ),( Koji Fujita ),( Tomoko Koide ),( Hirokazu Takahashi ) 대한소화기기능성질환·운동학회 2011 Journal of Neurogastroenterology and Motility (JNM Vol.17 No.2
Background/Aims There are few reports on the correlation between chewing gum and the gastrointestinal functions. But previous report showed use of chewing gum to be an effective method for controlling gastrointestinal symptoms. The aim of this study was to determine the correlation between chewing gum and gastric emptying using the continuous real time 13C breath test (BreathID system). Methods Ten healthy male volunteers participated in this randomized, 2-way crossover study. The subjects fasted overnight and were randomly assigned to chewing gum (Xylish, 2-3/1 tablet) for an hour following intake of a test meal (200 kcal/200 mL) or intake of the test meal alone. Gastric emptying was monitored for 4 hours after administration of the test meal by the 13C-acetic acid breath test performed continually using the BreathID system. Results No significant differences in the calculated parameters, namely, T1/2 (median, 111.82 vs 109.26 minutes; P = 0.575), Tlag (median, 53.28 vs 56.53 minutes; P = 0.333), gastric emptying coefficient (median, 3.58 vs 3.65; P = 0.285), regression-estimated constant β (median, 1.85 vs 1.80; P = 0.575) and regression-estimated constant κ (median, 0.61 vs 0.62; P = 0.959) were observed between the test meal alone group and the test meal and chewing gum group. Conclusions This study showed that chewing gum had no effect on the rate of gastric emptying. Therefore, since chewing gum did not enhance the speed of gastric emptying, it may ameliorate gastrointestinal symptoms through other mechanisms, such as saliva and autonomic nervous system. (J Neurogastroenterol Motil 2011;17:174-179)