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Impact of Bisoprolol on Ventricular Arrhythmias in Experimental Myocardial Infarction
김현국,임경섭,김성수,나주영 전남대학교 의과학연구소 2021 전남의대학술지 Vol.57 No.2
Following acute myocardial infarction (AMI), early use of beta-blockers (BBs) reduced the incidences of ventricular arrhythmia (VA) and death in the pre reperfusion era. However, some studies have reported a worsening of clinical outcomes and therefore, this study used a porcine model of AMI to evaluate the efficacy of bisoprolol on VAs and mortality. Twenty pigs were divided into two groups with one group using oral bisoprolol which was given for 3 hours before the experiment and then maintained for 7 days. A loop recorder was implanted, AMI was induced by balloon occlusion for 60 min, and then, reperfusion. One week later, the echocardiography and loop recorder data were analyzed in the surviving animals. Bisoprolol did not increase the heart rate (62.9±14.5 vs 79.0±20.3; p=0.048), lower the rate of premature ventricular contractions (PVC) (0.8±0.8 vs 11.0±12.8; p=0.021) or tend to lower recurrent VA (0.6±0.5 vs 1.1±1.1; p=0.131) during coronary artery occlusion. After reperfusion, bisoprolol did reduce VA in the early AMI period (0.1±0.3 vs 4.2±4.6; p=0.001) and it was not associated with the extent of myocardial recovery. In this porcine model, early oral bisoprolol might help reduce the incidences of PVC and recurrent VA and determine whether effects are more pronounced during the early AMI period. Our results suggest that bisoprolol might help reduce lethal VA and cardiac death following AMI in this reperfusion era.
김현국,이혜련,임충선,서봉국 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.79 No.-
Hybrid separation of dicyclopentadiene (DCPD) in a C5 stream was performed using a 1,1,3,3-tetraethoxy-1,3-dimethyl disiloxane (TEDMDS)-derived silica composite membrane. High purity DCPD, the keymonomer of the C5 stream can be concentrated by removing CPD through pervaporation from the CPDDCPDmixtures obtained by conventional distillation. Silica membranes were prepared using 1,1,3,3-tetraethoxy-1,3-dimethyl disiloxane (TEDMDS) by “spacer” and “template” techniques, which allowedfor control the pore size of silica membranes using bridged alkoxides that have pendant groups. TEDMDSderivedsilica membranes calcined at 450 C showed a high totalflux of 0.06–0.5 kg m 2 h 1 with a CPDseparation factor of 6–33 in a 95 wt% DCPD mixture, for feed temperature of 50–70 C. The silicamembranes prepared in this study shows relatively a highflux and acceptable separation factor. Therefore, they mayfind applications in commercial processes alongside the conventional distillation, bysaving energy and reducing byproducts.
김현국,서봉국,임충선 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.75 No.-
The production of cyclic carbonates from CO2 and epoxides has been extensively studied. We investigatedthe formation of a cyclic carbonate promoted by metal- and halide-free silica-supported alkanolamines. Moreover, we compared the obtained turnover numbers with those of the corresponding homogeneouscatalysts and confirmed that the reusability of the proposed heterogeneous catalysts was enhanced bythe utilization of polymer-type structures with amine/epoxy reaction around the silica. A cycliccarbonate yield of 70% and selectivity of 97% were achieved at 120 C and 10 bar afterfive-fold reuse of thecatalyst.
클라이밍운동중의 고칼슘섭취가 난소적출 흰쥐의 골밀도에 미치는 영향
김현국,이상직,류승필,장응찬,권태동,윤신중,이수천 한국운동영양학회 2002 Physical Activity and Nutrition (Phys Act Nutr) Vol.6 No.1
The purpose of this study was to determine the effect of climbing exercise on bone mineral content (BMC), bone mineral density (BMD), bone strength of different amount of calcium intake in ovariectomized (OVX)-rat cortical bone. Female SD rats(5 weeks old) were assigned to sedentary(SED; standard chow, 1.2% of calcium), OVX-normal calcium non-exercise(OC; standard chow, 1.2% of calcium), OVX-normal calcium exercise(OE; standard chow, 1.2% of calcium), OVX-high calcium exercise(OEH; 1.6% of calcium), and OVX-ultra high calcium exerdse(OEU; 3% of calcium) treatments. Training were daily endowed in the tower cage(vertical, 2 m length×30 cm width). Calcium intake group had significantly higher BMC, BMD and bone strength(P<0.05) at the femoral neck compared with control group, and there were not significant between OEH and OEU. These results suggested that climbing exercise with high calcium intake prevent losing bone mineral contents of ovariectomized rats.
힐버트 공간 채움 곡선을 이용한 공간 질의 결과 크기 추정
김현국,황환규 강원대학교 정보통신연구소 2003 정보통신논문지 Vol.7 No.-
Spatial query processing in large spatial databases costs very much. Therefore the query result size estimation is required to reduce the cost for the optimized query plan. To this end, we estimate the query result size from the summary data which is obtained by approximating the distribution and characteristics of the spatial data. new spatial partitioning technique based on the Hilbert space filling curve combined with the Equi-Count In this paper, we examine the several existing spatial partitioning techniques such as Equi-Area and Equi-Count partitioning, and R-tree indexing partitioning. We propose apartitioning technique. A variety of experiments demonstarate that the proposed partitioning technique is superior to the existing ones.