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고정층 반응기에서 HZSM-5 제올라이트 촉매를 사용한 올레핀의 전환반응
고태석,김나현 東新大學校 1995 論文集 Vol.7 No.-
Conversion reactions of ethylene, propylene and 1-butene over HZSM-5 zeolite and phosphorus-impregnated catalyst were studied. Conversion of lower olefin was increased with the order of ethylene<propylene<1-butene, showed maxima at 300∼350 ℃. Selectivity to lower olefin increased with reaction temperature, while higher olefins decreased. The decrease patterns of reactant concentration with space time are different. The decreasing rate of reactant is low at short space time in the conversion of ethylene, while the rate is high in the conversion of 1∼butene at short space time. For the conversion of propylene, autocatalytic characteristics is observed. The reaction of lower olefin described very well with proposed reaction path, which composed of adsorption of olefin, oligomerization of gaseous olefin with adsorbed olefin, cracking of oligomerization olefin to various hydrocarbons. The difference in reactivities of lower olefins, the reduction of activity with phosphorus impregnation, and lower conversion at higher temperature can be explaned in terms of surface concentration of adsorbed reactant and interaction between catalyst and reactant.
Ko, Won Jin,Na, Young Cheon,Suh, Bum Sin,Kim, Hyeon A,Heo, Woo Hoe,Choi, Gum Ha,Lee, Seo Ul Korean Society of Plastic and Reconstructive Surge 2013 Archives of Plastic Surgery Vol.40 No.6
Background We conducted an experimental study to compare the effect of massage using topical agents (Kelo-cote or Contractubex) on scar formation by massaging the healed burn wound on the dorsal area of Sprague-Dawley (SD) rats. Methods Four areas of second degree contact burn were made on the dorsal area of each of 15 SD rats, using a soldering iron 15 mm in diameter. After gross epithelialization in the defect, 15 SD rats were randomly divided into four groups: the Kelo-cote group, Contractubex group, Vaseline group, and control group. Rats in three of the groups (all but the Control group) were massaged twice per day for 5 minutes each day, while those in the Control group were left unattended. For histologic analysis, we performed a biopsy and evaluated the thickness of scar tissue. Results In the Kelo-cote and Contractubex groups, scar tissue thicknesses showed a significant decrease, compared with the Vaseline and control groups. However, no significant differences were observed between the Kelo-cote and Contractubex groups. In the Vaseline group, scar tissue thicknesses showed a significant decrease, compared with the control groups. Conclusions The findings of this study suggest that massage using a topical agent is helpful in the prevention of scar formation and that massage only with lubricant (no use of a topical agent) also has a considerable effect, although not as much as the use of a topical agent. Thus, we recommend massage with a topical agent on the post-burn scar as an effective method for decreasing the scar thickness.
Na Soo Jin,Oh Dong Kyu,Park Sunghoon,Lee Yeon Joo,Hong Sang-Bum,Park Mi Hyeon,Ko Ryoung-Eun,Lim Chae-Man,Jeon Kyeongman 대한의학회 2023 Journal of Korean medical science Vol.38 No.40
Background: This study aimed to evaluate whether the effect of tachycardia varies according to the degree of tissue perfusion in septic shock. Methods: Patients with septic shock admitted to the intensive care units were categorized into the tachycardia (heart rate > 100 beats/min) and non-tachycardia (≤ 100 beats/min) groups. The association of tachycardia with hospital mortality was evaluated in each subgroup with low and high lactate levels, which were identified through a subpopulation treatment effect pattern plot analysis. Results: In overall patients, hospital mortality did not differ between the two groups (44.6% vs. 41.8%, P = 0.441), however, tachycardia was associated with reduced hospital mortality rates in patients with a lactate level ≥ 5.3 mmol/L (48.7% vs. 60.3%, P = 0.030; adjusted odds ratio [OR], 0.59, 95% confidence interval [CI], 0.35–0.99, P = 0.045), not in patients with a lactate level < 5.3 mmol/L (36.5% vs. 29.7%, P = 0.156; adjusted OR, 1.39, 95% CI, 0.82–2.35, P = 0.227). Conclusion: In septic shock patients, the effect of tachycardia on hospital mortality differed by serum lactate level. Tachycardia was associated with better survival in patients with significantly elevated lactate levels.