Il-Mo Kang

Optimization of Illite Polytype Quantification Method

We proposed the revised full-pattern-fitting method of illite polytype quantification with background correction and scale factor correction of WILDFIREC simulated pattern, and R% value ((Σ|simulated-measured|/simulated)/ n×100) calculation, and then verified the reliability of this method by applying for the test sample (2M1:1M 1:1), and by comparing the result with Grathoff and Moore method (1996). We confirmed that the proposed method showed the error range of less than 3.6%, which is much lower than the previous full-pattern-fitting methods, in spite of the impurities of the test sample. In the comparison with Grathoff and Moore method for 2 tested samples, we obtained the relatively higher 2M1 contents using Grathoff and Moore method, whereas we obtained the reliable results with less than 10% of R% values.

Reactivated Timings of Some Major Faults in the Chugaryeong Fault Zone since the Cretaceous Period

Recently developed illite-age-analysis (IAA) approach has been applied to determine the multiple events for the Singal and Wangsukcheon faults in the Chugaryeong fault belt, Korea. Fault reactivated events during Late Cretaceous to Paleogene events(69.2±0.3 Ma and 27.2±0.5 Ma) for the Singal fault and of 75.4±0.8 Ma for the Wangsukcheon fault were determined by combined approach of the optimized illite-polytype quantification and the K-Ar age-dating of clay fractions separated from the fault clays. These absolute geochronological determinations of the multiple tectonic events recorded in the Chugaryeong fault belt are crucial to establish the tectonic evolution of the Korean Peninsula since Late Cretaceous.

Reactivated Timings of Inje Fault since the Mesozoic Era

Recently developed illite-age-analysis(IAA) approach was applied to determine the fault-reactivated events for the Inje fault that cut through Precambrian biotite granitic gneiss with NNE-SSW trend in the middle of Korean peninsula. Three distinct fault-reactivated events of shallow crustal regime were recognized using the combined approach of optimized illite-polytype quantification and K-Ar age-dating of clay fractions separated from 4 fault clay samples: 87.0±0.12 Ma, 65.5±0.05 and 66.6±1.38 Ma, 45.6±0.15 Ma, respectively. As well, 2M1 illite ages of 193~196 Ma and 254.3±6.96 were discernible, which may be related to the fault-activated time in the relatively deep crust. The study results suggest that the Inje fault would be firstly formed at 254.3°ae6.96 Ma and sporadically reactivated in shallow regime since about 87 Ma. These reactivation events in shallow regime might be due to the Bulguksa orogeny that would be strongly influenced in Korean peninsula at that time.

Gentamicin-intercalated smectite as a new therapeutic option for Helicobacter pylori eradication

Objectives Novel antibacterial strategies against Helicobacter pylori are needed because H. pylori strains are acquiring resistance to antibiotics. We evaluated the efficacy of gentamicin-intercalated smectite hybrid (S-GEN)-based treatment regimens in a murine model of H. pylori infection. Methods Two groups of 10 rats were administered either smectite or S-GEN to measure coverage of the gastric mucosa. To evaluate anti-H. pylori efficacy, mice were divided into eight groups of 10 mice each given different treatments, and H. pylori eradication was assessed by a Campylobacter-like organism (CLO) test and H. pylori PCR of the gastric mucosa, and H. pylori antigen and H. pylori PCR analysis of mouse faeces. The levels of proinflammatory cytokines were examined. Results S-GEN was retained in the gastric mucosal layer with a >60% distribution ratio for up to 1 h, and the S-GEN-based triple regimen decreased bacterial burden in vivo compared with that of untreated mice or mice treated with other regimens. The cure rates in the CLO test and H. pylori PCR from gastric mucosa were 70%, 60%, 80%, 50%, 60% and 60% in Groups III-VIII, respectively. Those for H. pylori PCR in the faeces of mice were 90% and 100% in Group III with standard therapy and Group V with triple therapy including S-GEN, respectively. S-GEN triple therapy also reduced the levels of proinflammatory cytokines. Conclusions These results suggest that S-GEN is a promising and effective therapeutic agent for the treatment of H. pylori infection.