Aphidicolin(APC)- induced Fragile Site Ferquency in 1st Metaphases Showing Different Responses to Phytohemagglutinin(PHA)Stimulation

Lee, Kwang Ho,Lee, Sok Woo,v, Chung Sik c 한국유전학회 1989 Genes & Genomics Vol.11 No.4

Using human lymphoytes stimulated with phytohemagglutinin (PHA), we investigated whether there is some difference between early- and late proliferating cells in the frequencies of fragile site induced by Aphidicolin (APC) which acts as a specific inhibitor of DNA polymerase. It was traced what concentration and treatment time of APC is the most appropriate to induce chromosomal aberrations in lymphocytes. We found that APC caused chromosomal lesion the most effectively when it was treated at 0.2μM for 25 hrs prior to harvest. In all cases observed, the frequencies of chromosomal breakage at 3p14 were found to be highly remarkable (p<0.01), and the frequencies of fragile site were considerably different among cultures undergone the 1st cycle of DNA replication, which each of them was harvested at different time aater PHA stimulation. These findings suggest that the cellular specificity in the receptor sites to PHA and the response to PHA stimulation may result in the different frequency of fragile sites.

Solving Mixed Strategy Nash-Cournot Equilibria under Generation and Transmission Constraints in Electricity Market

Lee, Kwang-Ho The Korean Institute of Electrical Engineers 2013 Journal of Electrical Engineering & Technology Vol.8 No.4

Generation capacities and transmission line constraints in a competitive electricity market make it troublesome to compute Nash Equilibrium (NE) for analyzing participants' strategic generation quantities. The NE can cause a mixed strategy NE rather than a pure strategy NE resulting in a more complicated computation of NE, especially in a multiplayer game. A two-level hierarchical optimization problem is used to model competition among multiple participants. There are difficulties in using a mathematical programming approach to solve a mixed strategy NE. This paper presents heuristics applied to the mathematical programming method for dealing with the constraints on generation capacities and transmission line flows. A new formulation based on the heuristics is provided with a set of linear and nonlinear equations, and an algorithm is suggested for using the heuristics and the newly-formulated equations.

Diffusion-mediated <i>in situ</i> alginate encapsulation of cell spheroids using microscale concave well and nanoporous membrane

Lee, Kwang Ho,No, Da Yoon,Kim, Su-Hwan,Ryoo, Ji Hee,Wong, Sau Fung,Lee, Sang-Hoon Royal Society of Chemistry 2011 Lab on a chip Vol.11 No.6

<P>Here, we present a novel and simple process of spheroid formation and <I>in situ</I> encapsulation of the formed spheroid without intervention. A hemispherical polydimethylsiloxane (PDMS) micromold was employed for the formation of uniform sized spheroids and two types of nano-porous membrane were used for the control of the crosslinking agent. We characterized the transport properties of the membrane, and the selection of alginate hydrogel as a function of gelation time, alginate concentration, and membrane type. Using the developed process and micromold, HepG2 cell spheroids were successfully formed and encapsulated in alginate without replating. This method allows spheroid encapsulation with minimal damage to the spheroid while maintaining high cell viability. We demonstrate the feasibility of this method in developing a bio-artificial liver (BAL) chip by evaluating viability and function of encapsulated HepG2 spheroids. This method may be applied to the encapsulation of several aggregating cell types, such as β-cells for islet formation and stem cells for embryonic body preservation, or as a model for tumor cell growth and proliferation in a 3D hydrogel environment.</P> <P>Graphic Abstract</P><P>The developed encapsulation method is useful for handling and controlling spheroids because transport and preservation of encapsulated spheroids is much easier than for non-encapsulated spheroids. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0lc00540a'> </P>

Remarks on the Pocklington and Padró-Sáez cube root algorithm in 𝔽 q

Lee, Kwang Ho,Kwon, Soonhak,Choi, Seokhwan,Koo, Namhun,Heo, Geon Institution of Electrical Engineers 2014 Electronics letters Vol.50 No.14

Understanding the Role of Nanoparticles in Nano-oil Lubrication

Lee, Kwangho,Hwang, Yujin,Cheong, Seongir,Choi, Youngmin,Kwon, Laeun,Lee, Jaekeun,Kim, Soo Hyung Springer-Verlag 2009 Tribology letters Vol.35 No.2

Spontaneous nanoscale polymer solution patterning using solvent evaporation driven double-dewetting edge lithography

Lee, Kwang-Ho,Kim, Sang-Mook,Jeong, Huisu,Jung, Gun-Young The Royal Society of Chemistry 2012 SOFT MATTER Vol.8 No.2

<p>We develop an innovative solution processable edge lithography, which we call double-dewetting edge lithography (DDEL). The polymer solution spontaneously dewets the hydrophobic regions and covers only hydrophilic regions on a surface energy-engineered substrate, which is achieved by a combination of conventional photolithography and a subsequent hydrophobic treatment of the exposed areas. Then, the secondary dewetting occurs through a coffee stain effect during the solvent evaporation, leaving polymer edge patterns behind. The whole double-dewetting phenomenon is complete within 1 s. This technique is a fast, cost-effective and easy direct solution patterning method, which enables nanoscale polymer edge patterns to be produced from various micron-scale platforms including lines, angular and irregular shapes.</p> <P>Graphic Abstract</P><P>During double-dewetting edge lithography, a polymer solution initially fully covers only hydrophilic treated circular surfaces. As the solvent evaporates, the solution moves towards the edges and the solute aggregates at the periphery of the circles, generating polymer ring patterns. <img src='http://pubs.rsc.org/ej/SM/2011/c1sm06431b/c1sm06431b-ga.gif'> </P>

Joint Estimation of the Outliers Effect and the Model Parameters in ARMA Process

Lee, Kwang-Ho,Shin, Hye-Jung Korean Data and Information Science Society 1995 한국데이터정보과학회지 Vol.6 No.2

In this paper, an iterative procedure, which detects the location of the outliers and the joint estimates of the outliers effects and the model parameters in the autoregressive moving average model with two types of outliers, is proposed. The performance of the procedure is compared with the one in Chen and Liu(1993) through the Monte Carlo simulation. The proposed procedure is very robust in the sense that applies the procedures to the stationary time series model with any types of outliers.

A 4-Week, Repeated, Intravenous Dose, Toxicity Test of Mountain Ginseng Pharmacopuncture in Sprague-Dawley Rats

Lee, Kwangho,Yu, Junsang,Sun, Seungho,Kwon, Kirok,Lim, Chungsan KOREAN PHARMACOPUNCTURE INSTITUTE 2014 Journal of pharmacopuncture Vol.17 No.4

Objectives: Mountain ginseng pharmacopuncture (MGP) is a pharmacopuncture made by distilling extract from mountain cultivated ginseng or mountain wild ginseng. This pharmacopuncture is injected intravenously, which is a quick, lossless way of strongly tonifying Qi function. The present study was undertaken to evaluate a 4-week, repeated, intravenous injection, toxicity test of MGP in Sprague-Dawley (SD) rats. Methods: Twenty male and female 6-week-old SD rats were used as subjects. We divided the SD rats into 4 groups: the high-dosage (10 mL/kg), medium-dosage (5 mL/kg), low-dosage (2.5 mL/kg) and control (normal saline) groups. MGP or normal saline was injected intravenously into the caudal vein of the rats once daily for 4 weeks. Clinical signs, body weights, and food consumption were monitored during the observation period, and hematology, serum biochemistry, organ weight, necropsy, and histological examinations were conducted once the observations had been completed. Results: No mortality was observed in any of the groups during the observation period. No changes due to MGP were observed in the experimental groups regarding clinical signs, body weights, food consumption, hematology, serum biochemistry, organ weight and necropsy. No histological changes due to MGP were observed in any of the male or female rats in the high-dosage group. Conclusion: During this 4-week, repeated, intravenous injection, toxicity test of MGP in SD rats, no toxic changes due to MGP were observed in any of the male or female rats in the high-dosage group. Thus, we suggest that the high and the low doses in a 13-week, repeated test should be 10 mL/kg and 2.5 mL/kg, respectively.

Intravenous Single-dose Toxicity of Mountain Ginseng Pharmacopuncture in Sprague-Dawley Rats

Lee, Kwangho,Sun, Seungho,Yu, Junsang,Lim, Chungsan,Kwon, Kirok KOREAN PHARMACOPUNCTURE INSTITUTE 2014 Journal of pharmacopuncture Vol.17 No.3

Objectives: Mountain ginseng pharmacopuncture (MGP) is an extract distilled from either mountain cultivated ginseng or mountain wild ginseng. This is the first intravenous injection of pharmacopuncture in Korea. The word intravenous does not discriminate between arteries, veins, and capillaries in Oriental Medicine, but only the vein is used for MGP. The aim of this study is to evaluate the intravenous injection toxicity of MGP through a single-dose test in Sprague-Dawley (SD) rats. Methods: Male and female 6-week-old SD rats were injected intravenously with MGP (high dosage of 20 mL/kg or low dosage of 10 mL/kg). Normal saline was injected into the rats in the control group by using the same method. After the rats has treated, we conducted clinical observations, body-weight measurements and histological observations. Results: In this study, no mortalities were observed in any of the experimental groups. Also, no significant changes by the intravenous injection of MGP were observed in the body weights, or the histological observations in any of the experimental groups compared to the control group. The lethal dose for intravenous injection of MGP was found to be over 20 mL/kg in SD rats. Conclusion: Considering that the dosage of MGP generally used each time in clinical practice is about 0.3 mL/kg, we concluded with confidence that MGP is safe pharmacopuncture.

Intravenous Single Dose Toxicity of Sweet Bee Venom in Sprague-Dawley Rats

Lee, Kwang-Ho,Yu, JunSang,Sun, Seungho,Kwon, KiRok KOREAN PHARMACOPUNCTURE INSTITUTE 2015 Journal of pharmacopuncture Vol.18 No.3

Objectives: Anaphylactic shock can be fatal to people who become hypersensitive when bee venom pharmacopuncture (BVP) is used. Thus, sweet bee venom (SBV) was developed to reduce these allergic responses. SBV is almost pure melittin, and SBV has been reported to have fewer allergic responses than BVP. BVP has been administered only into acupoints or intramuscularly, but we thought that intravenous injection might be possible if SBV were shown to be a safe medium. The aim of this study is to evaluate the intravenous injection toxicity of SBV through a single-dose test in Sprague-Dawley (SD) rats. Methods: Male and female 6-week-old SD rats were injected intravenously with SBV (high dosage: 1.0 mL/animal; medium dosage: 0.5 mL/animal; low dosage: 0.1 mL/animal). Normal saline was injected into the control group in a similar method. We conducted clinical observations, body weight measurements, and hematology, biochemistry, and histological observations. Results: No death was observed in any of the experimental groups. Hyperemia was observed in the high and the medium dosage groups on the injection day, but from next day, no general symptoms were observed in any of the experimental groups. No significant changes due to intravenous SBV injection were observed in the weights, in the hematology, biochemistry, and histological observations, and in the local tolerance tests. Conclusion: The results of this study confirm that the lethal dose of SBV is over 1.0 mL/animal in SD rats and that the intravenous injection of SBV is safe in SD rats.