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Sung-Ho Park,Doo-Sang Park,Kyung-Seop Ahn,Sei-Ryang Oh,Hyun-Woo Oh 한국응용곤충학회 2011 한국응용곤충학회 학술대회논문집 Vol.2011 No.10
A total of 5,000 ethanolic and methanolic extracts of different plant species from 23 nations including Costa Rica, Vietnam, Philippines, India, South Africa, Pakistan and Peru were evaluated for their larvicidal activities against Aedes aegypti, the major vector of dangue, dangue hemorhagic fever and yellow fever. The larval mortalities were observed 24h after treating the larvae to the extracts. At 500 ppm, 179 extracts showed >80% larval mortality in the 24h exposure. Among the extracts tested, the highest larval mortality was observed in the extracts of Piper guianense, Piper nigrum, Piper mocropodum, Piper sem-immersum, Piper magen and Piper pubicatulum. The LC50 value of extract P. guianense, P. nigrum, P. mocropodum, P. sem-immersum, P. magen and P. pubicatulum were 8.84, 11.48, 8.84, 13.86, 9.48 and 10.12 ppm against Ae. aegypti. It is suggested that P. guianense, P. nigrum, P. mocropodum, P. sem-immersum, P. magen and P. pubicatulum can be developed as potent larvicidal agents against Ae. aegypti.
Ahn, Sung Hyun,Park, Yong Kwang,Park, Eun-Sook,Kim, Jeong Han,Kim, Doo Hyun,Lim, Keo-Heun,Jang, Moon Sun,Choe, Won Hyeok,Ko, Soon Young,Sung, In-Kyung,Kwon, So Young,Kim, Kyun-Hwan American Society for Microbiology 2014 Journal of virology Vol.88 No.12
<P>The emergence of drug-resistant hepatitis B virus (HBV) is a major problem for antiviral treatment in chronic hepatitis B infection. In this study, we analyzed the evolution of drug-resistant mutations and characterized the effects of the rtA181T and rtI233V mutations on viral replication and drug resistance. We performed a clonal analysis of the HBV polymerase gene from serum samples during viral breakthrough treated with antiviral agents. A series of mutant clones containing rtA181T and/or rtI233V mutations were constructed and determined the effect of these mutations on the replication ability and drug resistance. An <I>in vitro</I> study revealed that the effect of the rtA181T mutation on viral replication and drug resistance is dependent on the mutations in the overlapping surface gene. Compared to the rtA181T surface missense mutation (rtA181T/sW172S), the introduction of rtA181T surface nonsense mutation (rtA181T/sW172*) resulted in decreased viral replication and increased drug resistance. Complementation assay revealed that the truncated PreS1 is responsible for reduced replication of rtA181T/sW172* mutant. Moreover, the rtA181T/sW172* mutant exhibited a defect in viral particle secretion. The rtI233V mutation that emerged during adefovir therapy reduced viral replication and conferred resistance to adefovir. Our data suggest that the impact of the rtA181T mutation on replication and drug resistance differs based on the mutation status of the corresponding surface gene. The rtI233V mutation also affects replication ability and drug resistance. This observation suggests the need for genotypic analysis of overlapping surface genes to manage antiviral drug resistance if clinical isolates harbor the rtA181T mutation.</P><P><B>IMPORTANCE</B> The emergence of drug-resistant HBV that are no longer susceptible to nucleos(t)ide analogues is a major problem for antiviral treatment in chronic hepatitis B infection. Among drug-resistant mutations, the single rtA181T mutation is known to confer cross-resistance to antiviral drugs. This mutation causes intermediate or reduced susceptibility to tenofovir. Moreover, the clinical occurrence of the rtA181T mutation during antiviral therapy is also high. Our study revealed that the effect of the rtA181T mutation on viral replication and drug resistance is dependent on the mutations in the overlapping surface gene. This observation suggests the need for genotypic analysis of overlapping surface genes to manage antiviral drug resistance if clinical isolates harbor the rtA181T mutation. We believe that our study will not only extend the understanding of the drug resistance mechanism, but it will also ultimately provide new treatment options for patients with multidrug resistant HBV.</P>
Control of Humanoid Robots Using Time-Delay-Estimation and Fuzzy Logic Systems
Ahn, Doo Sung The Korean Society for Fluid Power and Constructio 2020 드라이브·컨트롤 Vol.17 No.1
For the requirement of accurate tracking control and the safety of physical human-robot interaction, torque control is basically desirable for humanoid robots. Because of the complexity of humanoid robot dynamics, the TDC (time-delay control) is practical because it does not require a dynamic model. However, there occurs a considerable error due to discontinuous non-linearities. To solve this problem, the TDC-FLC (fuzzy logic compensator) is applied to humanoid robots. The applied controller contains three factors: a TDE (time-delay estimation) factor, a desired error dynamic factor, and FLC to suppress the TDE error. The TDC-FLC is easy to execute because it does not require complicated humanoid dynamic calculations and the heuristic fuzzy control rules are intuitive. TDC-FLC is implemented on the whole body of a humanoid, not on biped legs even though it is performed by a virtual humanoid robot. The simulation results show the validity of the TDC-FLC for humanoid robots.
Direct Detection of Drug-Resistant Hepatitis B Virus in Serum Using a Dendron-Modified Microarray
( Doo Hyun Kim ),( Hong Seok Kang ),( Seong-suk Hur ),( Seobo Sim ),( Sung Hyun Ahn ),( Yong Kwang Park ),( Eun-sook Park ),( Ah Ram Lee ),( Soree Park ),( So Young Kwon ),( Jeong-hoon Lee ),( Kyun-hw 대한간학회 2018 Gut and Liver Vol.12 No.3
Background/Aims: Direct sequencing is the gold standard for the detection of drug-resistance mutations in hepatitis B virus (HBV); however, this procedure is time-consuming, labor-intensive, and difficult to adapt to high-throughput screening. In this study, we aimed to develop a dendron-modified DNA microarray for the detection of genotypic resistance mutations and evaluate its efficiency. Methods: The specificity, sensitivity, and selectivity of dendron-modified slides for the detection of representative drug-resistance mutations were evaluated and compared to those of conventional slides. The diagnostic accuracy was validated using sera obtained from 13 patients who developed viral breakthrough during lamivudine, adefovir, or entecavir therapy and compared with the accuracy of restriction fragment mass polymorphism and direct sequencing data. Results: The dendron-modified slides significantly outperformed the conventional microarray slides and were able to detect HBV DNA at a very low level (1 copy/μL). Notably, HBV mutants could be detected in the chronic hepatitis B patient sera without virus purification. The validation of our data revealed that this technique is fully compatible with sequencing data of drug-resistant HBV. Conclusions: We developed a novel diagnostic technique for the simultaneous detection of several drug-resistance mutations using a dendron-modified DNA microarray. This technique can be directly applied to sera from chronic hepatitis B patients who show resistance to several nucleos(t)ide analogues. (Gut Liver 2018;12:331-341)
Sang Yean Kim,Jung Woo Eun,Hyung Seok Kim,Hee Doo Yang,Min Jeong Na,Young Min Ahn,Hae Ok Jung,Suk Woo Nam 대한독성 유전단백체 학회 2020 Molecular & cellular toxicology Vol.16 No.3
Background Pericardial effusion (PE) can develop in patients with virtually any condition that affects the pericardium, including acute pericarditis and a variety of systemic disorders. Thus, definite differentiation of malignant pericardial effusion and rapid diagnosis are known to have therapeutic and prognostic importance. Objective The aim of this study was to identify novel molecular markers for the detection of cancer in patients with pericardial disorder. Results We performed one-way ANOVA analysis of whole transcriptome scans of 18 PEs from the patients with pericardial disorder including cancer. It resulted in 4385 outlier genes. Hierarchical clustering analysis showed two distinct clusters [cancer patient’s PEs (G1 + G2) vs. non-cancer PEs (G3)] within the dendrogram. To identify cancer-specific molecular signature, Welch’s t test of G1 and G3 was performed and 1639 gene elements were suggested as stringent classifiers between cancer PE and non-cancer PE. Gene set enrichment analysis of PE signature suggested that CD24, SDC1, and ST14 were strong molecular markers for identifying cancer patients among patients with pericardial disorder. Conclusion Our results suggest that etiology-specific molecular signatures can discriminate cancer patients within pericardial disorder patients. CD24, SDC1, and ST14 are strong molecular markers for such discrimination.
Ahn, Sung Jun,Park, Mi-Suk,Lee, Jong Doo,Kang, Won Jun Japanese Society of Nuclear Medicine 2014 Annals of nuclear medicine Vol.28 No.5
<P>The histopathological grade of differentiation is one of the significant prognostic factors in pancreatic adenocarcinoma. Especially in the patients with unresectable pancreatic cancer, it is important to obtain the prognostic information non-invasively to avoid unnecessary invasive procedure. The aim of the study was to correlate (18)F-fluorodeoxyglucose (FDG) uptake with pathologic grade of pancreatic cancer, furthermore, to evaluate prognostic value of standardized uptake value (SUV).</P>