Laboratory and simulated field bioassays to evaluate larvicidal activity of pinus densiflora hydrodistillate, its constituents and structurally related compounds against aedes albopictus, aedes aegypti and culex pipiens pallens in relation to their inhibitory effects on acetylcholinesterase activity
Lee D.C.,Hankuk Academy of Foreign Studies |
Ahn Y.-J.,Seoul National University
Insects | Year: 2013
The toxicity of Pinus densiflora (red pine) hydrodistillate, its 19 constituents and 28 structurally related compounds against early third-instar larvae of Aedes albopictus (Ae. albopictus), Aedes aegypti (Ae. aegypti) and Culex pipiens palles (Cx. p. pallens) was examined using direct-contact bioassays. The efficacy of active compounds was further evaluated in semi-field bioassays using field-collected larval Cx. p. pallens. Results were compared with those of two synthetic larvicides, temephos and fenthion. In laboratory bioassays, Pinus densiflora hydrodistillate was found to have 24 h LC50 values of 20.33, 21.01 and 22.36 mg/L against larval Ae. albopictus, Ae. aegypti and Cx. p. pallens respectively. Among the identified compounds, thymol, c5-3-carene and (+)-limonene exhibited the highest toxicity against all three mosquito species. These active compounds were found to be nearly equally effective in field trials as well. In vitro bioassays were conducted to examine the acetylcholinesterase (AChE) inhibitory activity of 10 selected compounds. Results showed that there is a noticeable correlation between larvicidal activity and AChE inhibitory activity. In light of global efforts to find alternatives for currently used insecticides against disease vector mosquitoes, Pinus densiflora hydrodistillate and its constituents merit further research as potential mosquito larvicides. © 2013 by the authors; licensee MDPI, Basel, Switzerland.
Lee D.,Hankuk Academy of Foreign Studies |
Yoon T.,Korea University
2016 6th International Workshop on Computer Science and Engineering, WCSE 2016 | Year: 2016
Chikungunya Virus, which has no vaccines or medicines, is introduced into human population by mosquito bites. It is mostly occurred in Africa, Asia, Europe, and the Indian and Pacific Oceans. Dengue Virus, leading cause of death in the tropics and subtropics, is also transmitted by mosquitoes: 400 million infections every year. Chikungunya Virus and Dengue Virus share their clinical presentations such as joint pain, severe fever, and rash. There is no vaccine to prevent either Chikungunya Virus or Dengue Virus. In this paper, I analysed the DNA sequence of CHIKV and DENV in order to investigate the difference between them. Furthermore, I looked for the amino acid frequencies and found the genetic similarities and correlation between CHIKV and DENV.
Rahaman H.,Pohang Accelerator Laboratory |
Nam J.W.,Pohang Accelerator Laboratory |
Nam S.H.,Hankuk Academy of Foreign Studies |
Frank K.,Texas Tech University
IEEE Transactions on Plasma Science | Year: 2010
It is our interest to design and develop a high-power pulser system employing an electrical discharge in a spark gap. The type of discharge generates short electric pulses capable of both the characteristics of a fast rise time and a high repetition rate. Such a switch pulser has wide applications in the industry. To generate the electrical discharge in the spark gap in an efficient manner is very important for the switching operation. The regime of the operation utilizes the residual plasma in the interpulse recovery of the spark gap to increase the repetition rate. Therefore, the mechanisms of the discharge in a controlled manner following the electrical breakdown of the spark gap, such as the plasma generation in the spark channel and the dielectric recovery process as well as the residual plasma in the post-spark-discharge period, are of great importance. The understanding of the type of the spark-gap discharge for the switching at a high repetition rate beyond 1 MHz has been the primary goal. The typical voltage and current ratings are below 1 kV and several amperes, respectively. In particular, this paper addresses the optimal set of several parameters, such as the spark-gap geometry, electrode gap distance, gas pressure, and gas type, in conjunction with a unique circuit scheme to drive the discharge in the controlled fashion. © 2010 IEEE.
Kim G.O.,Hankuk Academy of Foreign Studies |
Kim N.,Hankuk Academy of Foreign Studies |
Kim D.Y.,Ajou University |
Kwon J.S.,Ajou University |
Min B.-H.,Ajou University
Molecules | Year: 2012
Considerable efforts have been devoted to control and maintain the sustained release of proteins. In this experiment, we used bovine serum albumin-fluorescein isothiocyanate (BSA-FITC) as a model protein to explore the potential utility of a chitosan and glycerol phosphate disodium salt (GP) hydrogel as a protein drug depot. The mixing of chitosan and GP solutions (0, 10, 20 and 30 wt%) formed a liquid at room temperature. At 37 °C, however, the chitosan/GP solutions formed hydrogels through an electrostatic crosslinking process. This electrostatic interaction between the chitosan, cationic amine group, and GP, anionic phosphate group, was confirmed by the changes of zeta potentials and particle sizes of this solution. The electrostatic interaction depended both on the GP ratios in chitosan and the incubation time of chitosan/GP solutions. Furthermore, BSA-FITC-loaded chitosan/GP hydrogels were examined for their ability as potential depots for the BSA drugs. Hence, when observed, the BSA-FITC-loaded chitosan/GP hydrogels showed an in vitro sustained release profile of BSA up to 14 days. Collectively, our results show that the chitosan/GP hydrogels described here, can serve as depots for BSA drugs. © 2012 by the authors.
Kim J.-H.,LG Corp |
Kim J.-W.,Hankuk Academy of Foreign Studies
Quality and Reliability Engineering International | Year: 2016
The lifetime and the reliability of Blu-Ray Recordable media were estimated with an acceleration test varying the temperature and the relative humidity. Some brand of the media showed relatively long lifetime over 80 years, but another brand was immeasurable because the media was broken during the acceleration procedure. A strong dependence of the lifetime of the media on the brand was observed. Effect of the initial recording performance in terms of the random symbol error rate and the jitter on the reliability was analyzed. The random symbol error rate showed a strong correlation with the reliability of the Blu-Ray Recordable media. Copyright © 2014 John Wiley & Sons, Ltd.
Kwon S.Y.,Hankuk Academy of Foreign Studies
33rd Asian Conference on Remote Sensing 2012, ACRS 2012 | Year: 2012
This research was conducted to examine and assess the vulnerability of Korean urban areas to heavy rainfalls and propose a viable solution in preventing floods. The target of this research was Ansan of Gyeonggi Province, an urban area with Ansan and Hwajeong Streams and big river basins. To determine the status of Ansan's flood precaution, a simulation of heavy torrential rain was run on Ansan urban basins using the model CAMEL. The result was that Ansan is inadequately prepared for heavy rainfalls. Simulation showed that most of Ansan's downtown areas will flood during the heavy rain. From the simulation, a list of regions that are most vulnerable to flooding and attention has been compiled. To prevent further flooding in Ansan, this research tested scenarios with different flood preventative measures. After comparing different scenarios, it was discovered that reducing the impervious surfaces and adjusting water content and hydraulic conductivity of the soil show a significant decrease in the level of flooding.
Lee S.,Hankuk Academy of Foreign Studies
Proceedings of 2015 IEEE Advanced Information Technology, Electronic and Automation Control Conference, IAEAC 2015 | Year: 2015
Speech Emotion Recognition technique is incredible in that it can open a way of communication between human and computer. The applications vary from educational software, psychiatric diagnosis, and interrogation to intelligent toys. It has been a long way for researchers who dedicated to search for the best models for speech emotion recognition. This paper proposes a novel hybrid model that combines the K-Nearest Neighbor (KNN) model and the Naïve Bayes (NB) classifier: a model which was inspired from the hybrid model of Support Vector Machine (SVM) and K-Nearest Neighbor method. The implementation of NB-KNN overcomes risks of SVM-KNN model and outperforms the original models that it is composed of. © 2015 IEEE.
Kim K.,Hankuk Academy of Foreign Studies
2015 2nd International Conference on Computer Science, Computer Engineering, and Social Media, CSCESM 2015 | Year: 2015
There are not a lot of artworks which touches on randomization. Artists such as Jackson Pollock, Karl Sim, and Gregory Volk tried to reach true randomness in their artworks. However, In this paper, I will evaluate why those artists failed to achieve randomness and create artworks using the random number generator in order to reach the true randomness. © 2015 IEEE.
Rahaman H.,Pohang Accelerator Laboratory |
Nam S.H.,Pohang Accelerator Laboratory |
Nam J.W.,Hankuk Academy of Foreign Studies |
Lee B.-J.,Goethe University Frankfurt |
Frank K.,Friedrich - Alexander - University, Erlangen - Nuremberg
Applied Physics Letters | Year: 2010
The electrical breakdown in a spark gap for repetitive switching has been a long research interest. For this purpose, microplasma discharge is implemented in the spark gap which is further integrated inside a coaxial transmission line. This work addresses important physical properties and insights of the microplasma discharge, to be optimized, such as plasma generation in a spark channel, dielectric recovery process, and residual plasma in the postspark discharge period. Although understanding the microplasma discharge is the primary goal, considerable attention has been focused on an external circuit scheme to drive the discharge system at a high repetition rate. © 2010 American Institute of Physics.
Kim G.-H.,Hankuk Academy of Foreign Studies |
Kim B.-J.,Youngsan University
International Journal of Multimedia and Ubiquitous Engineering | Year: 2014
In this research we implement an EEG based music therapy. Music therapy can help the student deal with the stress, anxiety and depression problems. To do so we will develop EEG-based human emotion recognition algorithm. Proposed training program works as a therapist. The music choice and duration of the music is adjusted based on the student's current emotion recognized automatically from EEG. If the happy emotion is not induced by the current music, the system would automatically switch to another one until he or she feel happy. Proposed system is personalized brain music treatment that is making a brain training application running on smart phone or pad. That overcomes the critical problems of time and space constraints of existing brain training program. By using this brain training program, student can manage the stress easily without the help of expert. © 2014 SERSC.