• Applied Biological Chemistry
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• v.37 no.1
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• pp.56-63
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• 1994

Oligonucleotides for a conserved region of the coat protein gene of cucumber mosaic virus (CMV) and a hammerhead structure ribozyme against CMV RNA were synthesized using a DNA synthesizer. Both strands of oligonucleotides were annealed and restricted with BamHI/SacI, then cloned into a plasmid pBS SK (+). The cloned CMV substrate and ribozyme were sequenced to verify correct constructions. In vitro transcriptions were carried out by using T7 RNA polymerase with BssHII or SspI digests of $1\;{\mu}g$ of substrate and ribozyme clones. The size of substrate RNA was 176 nucleotides (nt) containing 50 nt of CMV RNA sequence, 6 nt of XbaI restriction site and 120 nt of vector-derived sequence in the case of BssHII digest. The size of ribozyme RNA was 164 nt containing 40 nt of ribozyme RNA sequence and same sequences of substrate. Substrate RNA was efficiently cleaved into two fragments (96 nt and 80 nt) by ribozyme RNA. This endonucleolytic cleavage occurred more efficiently at $55^{\circ}C$ than $37^{\circ}C$. SspI digest-derived substrate RNA (2234 nt) was also cleaved into two fragments by the same ribozyme. SspI digest-derived ribozyme RNA (2222 nt) cleaved the above substrate to two fragments. In vitro-tested ribozyme construct is being cloned into a plant transformation vector to develop virus-resistant plants.

• Applied Biological Chemistry
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• v.46 no.4
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• pp.353-360
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• 2003

For the simple rapid bioassay of organophosphorus and carbamate pesticide residues, a mass-production system of acetycholinesterase (AChE, EC 3.1.1.7, MAChE) using baculovirus and insect cell culture was constructed. The cDNA for AChE was synthesized from Drosophila melanogaster in Halla Mountain, the lipid anchor tail was removed by PCR and was used for the site-directed mutagenesis of three amino acid residues (E107Y, F368L, L408F). The mutated cDNA was inserted into the baculovirus vector and expressed in insect cells. Maximum cell growth and enzyme activity were reached when the cells $(2{\times}10^6\;cell/ml)$ were infected four times at four-day-intervals. His-tag containing MAChE was purified using Ni-NTA column and used for characterization. The activity was maintained under various pHs (3-10) and temperatures $(20-50^{\circ}C)$ under experimental conditions. As an extraction solution for pesticides, methanol is more effective than ethanol. Against major organophosphate and carbamate pesticides, the MAChE showed better sensitivity than AChE and AChE from housefly (Taiwan).

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.12
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• pp.65-72
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• 2008

This paper proposes a new dual-loop digital PLL(DPLL) using seamless frequency tracking methods. The dual-loop construction, which is composed of the coarse and fine loop for fast locking time and a switching noise suppression, is used successive approximation register technique and TDC. The proposed DPLL in order to compensate the quality of jitter which follows long-term of input frequency is newly added cord conversion frequency tracking method. Also, this DPLL has VCO circuitry consisting of digitally controlled V-I converter and current-control oscillator (CCO) for robust jitter characteristics and wide lock range. The chip is fabricated with Dongbu HiTek $0.18-{\mu}m$ CMOS technology. Its operation range has the wide operation range of 0.4-2GHz and the area of $0.18mm^2$. It shows the peak-to-peak period jitter of 2 psec under no power noise and the power dissipation of 18mW at 2GHz through HSPICE simulation.

• Microbiology and Biotechnology Letters
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• v.9 no.3
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• pp.159-164
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• 1981

Reinforced Calcium-alginate gel entrappment method for enzyme immobilization is described with an example of penicillin amidase from Bacillus megaterium KFCC 10029, a partially constitutive mutant of B. megaterium ATCC 14945. Penicillin amidase recovered from the fermentation broth by adsorption on celite is mixed with alginate and gelatin solution, and cast into a pellet or noodle form by coagulation in calcium salt solution followed by crosslinking with glutaraldehyde. Optimum pH and temperature of the immobilized enzyme preparation were 8.0 and 6$0^{\circ}C$, respectively. Kinetic constants such as Km value and the inhibition constant of 6-APA and phenylacetic acid were 2.6 mM, 7.4 mM and 21.2 mM, respectively. The enzyme leakage from the adsorbent during operation was successfully prevented owing to the increase of physical strength of gel coat. The half lives in a column reactor were 6 and 30 days at the respective temperature of 4$0^{\circ}C$ and 3$0^{\circ}C$, which were the 6-8 fold increased values as compared with those of without entrappment. The results highly recommended the use of reinforced Calcium-alginate gel entrappment method for the enhancement of physical strength and the operational stability of alginate gel entrapped enzyme.

• The Korean Journal of Pharmacology
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• v.27 no.1
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• pp.7-12
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• 1991

We measured the developmental increase of tyrosine hydroxylase(TH) activity and dopamine content with high performance liquid chromatography with electrochemical detection(HPLC-EC) in dissociated cultures of fetal rat brainstem(E14). TH activity and dopamine content increased progressively upto 7 days in vitro, when the effects of various drugs on the dopamine contents were studied. ${\alpha}-Methyl-p-tyrosine$, a TH inhibitor and NSD-1015, an inhibitor of aromatic amiono acid decarboxylase effectively depleted dopamine contents. Dopamine contents were depleted by reserpine and increased by pargyline. When cultures grown for 1 week in control medium were then exposed to tetrodotoxin$(0.1\;{\mu}M$) for 7 days, exposure to tetrodotoxin markedly decreased TH activity. All the above results indicate that dopamine metabolism in the cultered cells reflect reliably the property of brain dopamine metabolism. We suggest that measuring TH activity and dopamine content in brainstem culture with HPLC-EC can be useful tool in the study of pharmacology as well as toxicology of the central dopaminergic system.

• Journal of Plant Biotechnology
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• v.29 no.2
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• pp.93-98
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• 2002

A VP6 fragments was subcloned with BamHI in the binary pMBP-1 vector under Califlower Mosaic Virus (CaMV) 355 promoter and neomycin phosphotransferase II (npt II) gene. The recombinant binary vector was mobilized into Agrobacterium-tumefaciens LBA4404 by the freeze-thaw method and potato (Solanum tubensum L. cv Desiree) was transformed by modified leaf-disc cocultivation. Shoots were induced on MS medium with 0.01 mg/L NAA, 0.1 mg/L GA$_3$, 2.0 mg/L Zeatin, 100.0 mg/L kanamycin, 500.0 mg/L carbenicillin. In order to identify the copy number of VP6 into potato plant, total genomic DNA was isolated from transgenic potato and analysed by Southern blotting. Genomic DNA and total mRNA analysis demonstrated the incorporation of the foreign gene into the potato genome, as well as their transcription.

• Childhood Kidney Diseases
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• v.1 no.2
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• pp.151-154
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• 1997

Purpose : The prevalence of renal malformation in Turner syndrome has been quoted as being greater than 50% in older series. Recently in 1988, Lippe's review gave a prevalence of 33%, significantly lower than all previous reports. In 1996, Flynn reported that renal malformation occurs in approximately 24% of all girls with Turner syndrome, and that it is seldom seen in girls with mosaic karyotype who form the predominant subgroup. The aim of this study was to evaluate prevalence of renal malformation by karyotype in Turner syndrome in Korea. Method : We evaluated 81 patients with Turner sundrome diagnosed in Yonsei University from Jan. 1987 to Dec. 1996. The patient entered in this study were those for whom both karyotype and ultrasound examination of the kidney were available. Result : 1) The karyotype showed: 45,X ; 29 cases (38%), mosaicism : 32 cases (40%), structural aberration ; 17 cases (22%). 2) Of the 29 cases of pure 45,X karyotype, 5(17%) had abnormal renal findings, while these were found in only 1 of the 30 mosaic cases(3.3%), and in 1 of the 17 structural aberration cases(6%). The malformation included 3 cases of horseshoe kidney, 2 cases of axial malrotation, hypoplastic kidney and simple cyst each one. There was no statistical significance between 3 groups (p=0.09). Conclusion : We conclude that renal malformation occurs in 9.2% in this study, therefore Korean girls with Turner syndrome have lower rates of renal malformation.

• The Plant Pathology Journal
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• v.19 no.2
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• pp.97-101
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• 2003

This study was conducted to determine the efficacy of Epicoccosorus nematosporus for the control of Eleocharis kuroguwai and to evaluate the meteorological factors which affect weeding efficacy in field conditions for three years (1996-1998). The best time to control E. kuroguwai with E. nematosporus as a biological control agent in the field was in July, when temperature ranged from 20.4 to $23.4^{\circ}C$; the surface wetness duration was 12.6-16.1 hours, and application time of 6:00 p.m. and 8:00 p.m.; and weeding efficacy was 81-90%. On 10 June 1996 in Milyang area, where the field experiments were performed, mean temperature was $16.5^{\circ}C$ with 11.3 hours of dew duration. Meanwhile, on 20 Aug. 1996 the temperature was $21.3^{\circ}C$ with 15.4 hours of dew duration. During these periods, the weeding efficacy was recorded at 61.8 and 60.8%, respectively. Time required for complete plant death was 25.8 and 25.6 days at application times 10 June and 20 Aug., respectively. At the time of application on 7,18, and 27 July 1996, mean temperature was 20.4-$23.4^{\circ}C$ with 12.6-16.5 hours of dew duration. The weeding efficacies of these periods were very hi일 with 81.4-90.8%. Three years of field observations from 1996 to 1998 showed that infection in the field can occur at any time through the summer season, although total infection rates vary between months and between years. In 1996, plant infection rapidly increased from 56% on 30 June, 82.4% on 15 July, 94.6% on 15 August, and 92.8% on 15 September under favorable meteorological conditions such as minimum temperature of $17.6^{\circ}C$ and maximum temperature of $27.1^{\circ}C$, with 86% relative humidity and 977.5 mm of rainfall during E. kuroguwai growing season. However, in 1997, the disease incidence was very low because of unfavorable weather conditions brought about by the hot temperature and the low amount of rainfall at 321.5 mm. Disease progress was slow from 24.4% on 30 June to 49.2% at the end of the growing season.

• The Journal of Engineering Geology
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• v.15 no.4 s.42
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• pp.391-405
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• 2005

Chemical and isotopic analysis for stream water, shallow groundwater, intermediate groundwater and deep groundwater was carried out to grasp hydrogeochemical characteristics of groundwater in the Heunghae area, Pohang city. Water type of stream water and shallow groundwaters is typified as Ca-Cl type, intermediate groundwater is $Na-HCO_3$, and deep groundwater is prominent in Wa-Cl type. $HCO_3^-\;and\;SiO_2$ in shallow groundwater are originated from weathering of silicate minerals, whereas those of deep groundwaters are resulted from weathering of carbonate minerals. Ca and Mg ions in both shallow and deep groundwaters are resulted from weathering of calcite and dolomite. $SO_4^{2-}$ in shallow groundwater is originated mainly from pyrite oxidation. As well depth increases, pH and TDS increase, but Eh and DO decrease. Alkali metal contents(K, Na, Li) increases as well depth increases, but alkali earth metal(Mg, Ca) and hi concentrations increase as well depth decreases. Anions, halogen elements(F, Cl, Br), and $HCO_3$ contents increase as well depth increases. The average stable isotope value of the groundwater of each depth is as follows; deep groundwater: ${\delta}^{18}O=-10.1\%o,\;{\delta}D=-65.8\%_{\circ}$, intermediate groundwater: ${\delta}^{18}O=-8.9\%_{\circ},\;{\delta}D=-59.6\%_{\circ}$, shallow groungwater : ${\delta}^{18}O=-8.0\%_{\circ},\;{\delta}D=-53.6\%_{\circ}$, surface water : ${\delta}^{18}O=-7.9\%_{\circ},\;{\delta}D=-53.3\%_{\circ}$ respectively.

• Applied Chemistry for Engineering
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• v.18 no.1
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• pp.29-35
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• 2007

Recently, due to narrow margin on design factor of flue gas desulfurization (FGD) systems or aging of systems, some problems such as decrease of $SO_2$ removal efficiency and difficulty on coping with unstable state are arising on FGD systems. On this study, to cope with these problems several methods such as adjustment of reagent pH, inlet $SO_2$ concentration, variation of units of operation pump, installation of liquid distribution ring (LDR) were attempted to increase the $SO_2$ removal using spray type simulated FGD system. Also, sulfite and Al/Fx ion effects on limestone blinding were experimented. When three absorber recirculation pumps were operated, $SO_2$ removal was increased by 12% in comparison with that of two pumps operation. $SO_2$ removal was increased by 2~7% after installation of LDR. Dissolved oxygen increased up to 0.5 ppm and limestone binding effect was alleviated after injection of dibasic acid (DBA) with the concentration of 500 and 1,000 ppm. When $Al^{3+}$ and $F^-$ ions were coexisting, the dissolution rate of limestone was decreased by 20%.