Dong-Myung Kim

A Semicontinuous Prokaryotic Coupled Transcription/Translation System Using a Dialysis Membrane

This report describes a novel and simple cell‐free protein synthesis system. In this paper, we prove that the short duration of protein synthesis in a conventional cell‐free protein synthesis system of batch configuration can be attributed both to depletion of energy sources and deactivation of S30 extract by small‐molecule byproducts produced during the protein synthesis. The reaction period of cell‐free protein synthesis system could be extended through an operation of a continuous‐flow cell‐free protein synthesis system, which was originally developed by Spirin. However, inspite of the greatly extended reaction period, the final amount of cell‐free produced protein was not significantlly larger than that can be obtained from a batch system due to the reduced rate of protein synthesis. It was supposed that the reduced rate of protein synthesis in the continuous‐flow system was attributed to leakage of translational components through the ultrafiltration membrane during the operation of the continuous‐flow system. To solve such a problem of the continuous‐flow system, we have developed and operated a novel reactor for cell‐free protein synthesis. By use of this system, protein synthesis occurred for at least 14 h, yielding 1.2 mg/mL CAT protein. The present system is superior to the continuous‐flow system as well as the conventional batch system in that it enables extremely high productivity without using any complex and hard‐to‐handle apparatus. As far as we know, the yield of cell‐free protein synthesis given above is the best of the results reported to date.

Analysis of asymmetric giant magnetoimpedance in field-annealed Co-based amorphous ribbon

The asymmetric giant magnetoimpedance (GMI) profile has been realized in weak-field-annealed Co-based amorphous ribbon at the annealing temperature of 380 °C in open air. Asymmetric GMI profiles with respect to applied field become profound as the annealing field increases over 500 mOe. The asymmetric GMI profile at the frequencies of ac current over 0.5 MHz is well ascribed for by the rotational transverse magnetization of single domain under a uniaxial anisotropy in amorphous core and a unidirectional anisotropy due to the exchange coupling with the bias field in the crystalline layer, underlying surface oxidation layer developed during the annealing in open air.

Epidemiologic Characteristics of Intraocular Pressure in the Korean and Mongolian Populations: The Healthy Twin and the GENDISCAN Study

PURPOSE The purpose of this study was to demonstrate a negative association between intraocular pressure (IOP) and age in 2 Asian populations. In addition, we evaluated genetic and nongenetic factors associated with IOP. DESIGN Family-based cohort study. PARTICIPANTS Study subjects >10 years of age from one Korean (The Healthy Twin; n = 1431) and 2 Mongolian populations (The GENDISCAN; n = 859 and 806) with IOP values. METHODS The IOP values were measured with a noncontact tonometer. Each participant received a standard health examination and received questionnaires, which include candidate risk factors on IOP. Mixed models were used to identify risk factors for IOP. Variance-component methods were applied to estimate the heritability of IOP. MAIN OUTCOME MEASURES The negative trend of IOP with aging and evaluation of impact of genetic and nongenetic components on IOP. RESULTS The mean ages were 43.6, 34.1, and 36.3 years for the Korean, Orhontuul, and Dashbalbar populations, respectively. The mean IOPs were 14.4 mmHg (95% confidence interval [CI], 14.3-14.6) in the Koreans and 14.1 mmHg (95% CI, 13.9-14.3) and 12.6 mmHg (95% CI, 12.4-12.9) in the Orhontuul and Dashbalbar populations, respectively. In the 3 populations, the IOP decreased as age increased. We replicated an association of systolic blood pressure (SBP) with IOP. In addition, components of the metabolic syndrome (MS), such as plasma glucose, lipid level, and body mass index, showed positive associations with IOP, after adjusting for age and SBP. The IOP also had strong genetic contributions in all populations (heritability, 0.47-0.51). CONCLUSIONS Negative associations between age and IOP were observed in all 3 populations, which cannot be explained by the increasing prevalence of myopia in the younger generation. The different age trend in IOP may in part be responsible for differences in the prevalence of glaucoma subtypes. Our findings suggest that associations between IOP and MS components were independent of established risk factors such as SBP or age. In addition, the importance of inherited risks requires further genetic dissection of IOP determinants for biological understandings of underlying pathophysiology.

Segmentation of Optic Nerve Head using Warping and RANSAC

Glaucoma is the second leading cause of blindness, and the retinal nerve fiber layer (RNFL) defect is the early sign of the glaucomatous optic nerve damage. To evaluate the RNFL, segmentation of the optic nerve head on the RNFL photograph should be the first step. This paper presents segmentation of optic nerve head using warping and random sample consensus (RANSAC). Sensitivity and positive predictability of the proposed method were 91% and 78% respectively.

Enhancement of protein synthesis with sodium ion in a cell-free system from Escherichia coli

We have previously shown that some types of synthetic zeolites can enhance protein synthesis in a coupled cell-free transcription/translation system derived from Escherichia coli. As a result of efforts to elucidate the mode of action of zeolite on protein synthesis, we found that enhancement mainly resulted from the ion exchange reaction induced by the addition of the zeolite. Even in the absence of zeolite, the yield of protein synthesis in the cell-free system was markedly increased by replacing the potassium ion in the reaction mixture with sodium ion.

Change of GMR parameters in N-ion implanted spin-valve

Abstract Giant magnetoresistance (GMR) profiles have been measured as a function of the thickness of pinned NiFe layers for N-ion implanted spin-valve samples. The measured results are analyzed using the double-domain model (DDM), newly introducing the magnetic viscosity effect retarding the domain rotation by the defect or pinning centers. The hysteresis increase of GMR profiles after the ion implantation at θ =90° can be explained by the magnetic viscosity effect of pinned NiFe layer. The simulation results, well fitted with the measured data, indicate that the N-ion implantation significantly raises the magnetic viscosity effect of the pinned NiFe layer. The magnetic viscosity effect after N-ion implantation exponentially decreases with the thickness of the pinned NiFe layer.

Temperature dependence of GMR profiles in N-ion implanted spin valve

Abstract The temperature dependence of giant magnetoresistance (GMR) profiles has been measured in the N-ion implanted spin valves. The N-ion implantation significantly reduces the exchange coupling field H ex , which causes the change of magnetoresistance (MR) profile after the ion implantation. The broadening and shifting of the peaks of MR profiles with decreasing temperature are dominantly affected by the increase of coercive field H c of pinned layer.