• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.150-153
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• 2000

In this paper, we have designed a 2 stage MMIC power amplifier which has flat gains of in-band and reasonable out-band cutoff characteristics using 0.5$\mu\textrm{m}$ MESFET libra교 of ETRI. For the 1st stave, we obtaind P$_{1dB}$ of 9.2 dBm and gain 10.8 dB using 6 finger D-MESFET and P$_{1dB}$ of 18.4 dBm and gain of 10.8 dB using 14 finger D-MESFET for the 2nd stage, which is power matched using LIBRA's embedded TUNER. Also in-band gain flatness and out-band cutoff characteristics are obtained by attaching LC tank in the output matching circuit. The designed 2 stage MMIC power amplifier has bandwidth of 0.95～2.8 GHz, gain of 20 dB and P$_{1dB}$of 17.2 dBm. Especially gain flatness of $\pm$0.8dB was obtained in 1.8～2.5 GHz frequency ranges. And chip size is 1.4$\times$1.4 mm..4 mm.

• BMB Reports
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• v.32 no.2
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• pp.161-167
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• 1999

The role of oxidative stress in the initiation and the complication of diabetes was examined by monitoring blood glucose increase and oxidative DNA damage in rats treated with alloxan or streptozotocin (STZ). Oxidative DNA damage was assessed by quantitating 8-oxo-2'-deoxyguanosine ($oxo^8dG)$ excreted in urine and the $oxo^8dG$ accumulated in pancreas DNA. Both alloxan and STZ treatments resulted in an abrupt increase in blood glucose and significant increases in urinary and pancreatic $oxo^8dG$. Pretreatment of buthionine sulfoximine (BSO), a glutathione-depleting agent, slightly potentiated the increase of blood glucose and urinary $oxo^8dG$ in the alloxan- and STZ-treated rats. Furthermore, the BSO pretreatment caused significant amplification of pancreatic $oxo^8dG$ increase in the rats. On the other hand, pretreatment with 1,10- phenanthroline (o-phen), a chelator of divalent cations, showed different results between alloxan- and STZ-treated rats. The o-phen pretreatment completely blocked diabetes and the increase of $oxo^8dG$ by alloxan treatment, while it potentiated the increase of blood glucose and $oxo^8dG$ by STZ treatment. The results demonstrate that the causative effect of alloxan on diabetes may be the generation of reactive oxygen species through a Fenton type reaction, but that of STZ may not.

• Journal of the Korean Chemical Society
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• v.45 no.4
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• pp.312-317
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• 2001

7'-Aldehyde-nucleosides analogue (2a, 2c) were synthesized from 6-N-benzoyl-2',3'-O-isopropylideneadenosine and uridine. The condensation of 2 with ethoxycarbonylmethylene Wittig reagent produced the adenosine and uridine analogues containing extended conjugated diene and ethoxycarbonyl group, ethyl-1',5',6',7',8'-pentadeoxy-1'-(adenin-9-yl)-$\beta$-D-ribo-nona-5'(E),7'(E)-dienofuranuronate (4b) and ethyl-1'. 5',6',7',8'-pentadeoxy-1'-(uracil-1-yl)-$\beta$-D-ribo-nona-5'(E),7'-(E)-dienofuranuronate (4c). 9-[8',8'-dibromo-5',6',7',8' -tetradeoxy-$\beta$-D-ribo-octa-5'(E),7'(E)-diene]nucleosides (6b, 6c) were also prepared from 2 with similar method.

• Journal of Preventive Medicine and Public Health
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• v.27 no.1 s.45
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• pp.84-106
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• 1994

Hyperbaric oxygen (HBO) therapy for carbon monoxide (CO) poisoning eventually inducing the hypoxia-reoxygenation condition, may produce oxygen free radicals, which forms 8-hydroxydeoxyguanosine (8-OH-dG) by attacking C-8 position of deoxyguanosine (dG) in DNA. Effects of oxygen partial pressure or duration of HBO therapy with or without CO poisoning on the tissue 8-OH-dG formation were investigated. Male Sprague-Dawley rats were grouped and exposed to air (control group), 4000 ppm of CO for 10 to 30 minutes (CO only group), air for 30 minutes after 30 minute exposure to 4000 ppm of CO(CO-air exposure group), HBO after 30 minute exposure to 4000 ppm of CO(CO-HBO group), or HBO therapy fo. $10{\sim}120$ minutes(HBO only group). The 8-OH-4G concentrations in the brain and the lung tissues were measured with high performance liquid chromatography and electrochemical detector (ECD). Average concentrations of the 8-OH-dG of each group were statistically compared. In the brain tissues, 8-OH-dG concentrations of the CO only group, the CO-air exposure group, and the CO-HBO group did not significantly differ from those of the control group. Similar insignificance was also found between the CO-HBO group and the HBO only groups. No appreciable dose-response relationship was observed between the 8-OH-dG concentration and the oxygen partial pressure or the duration of HBO. However, the 8-OH-dG concentrations of the 30 minute CO only group were higher than those of the CO-air exposure group (p-value<0.05). In the lung tissues, there were no significant differences between the 8-OH-dG concentrations of the control group and those of the CO only group, the CO-air exposure group, and the CO-HBO group. However, mean 8-OH-dG concentration of the CO-air exposure group was significantly higher than that of the CO only group under the same CO exposure condition(p-value<0.05). With the duration of CO exposure, the 8-OH-dG concentrations of the lung tissues decreased significantly (p-value<0.05). The concentrations of 8-OH-dG in the lung tissues proportionally increased with the duration of HBO, but no such relation was observed with the oxygen partial pressure. These results suggest that the brain may be more resistant to oxygen free radicals as compared with the lungs, and that oxygen toxicity following HBO may be affected by factors other than oxygen free radicals.

• Korean Journal of Plant Tissue Culture
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• v.25 no.1
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• pp.1-5
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• 1998

This study describes the effect of the growth regulators such as 2,L-D and BA, on the structural abnormalities of somatic embryos derived from leaf explants of Angelica gigas Nakai, Also, the relationship between the cotyledon number of a somatic embryo and its germinability is explored. Embryogenic calli were selected from calli formed on explants cultured on MS solid basal medium supplemented with 0.5mg/L 2,4-D, 1mg/L 2,4-D, 1mg/L plus 0.1mg/L BA, and 1 mg/L 2,4-D plus 0.5mg/L BA. Cotyledonary abnormalities were observed in somatic embryos which were developed from embryogenic calli cultured on MS medium containing 1mg/L 2,4-D for 8 weeks and then subcultured on 2,4-D free MS medium for 3 weeks. The frequency of abnormalities was as follows: 22.8% one cotyledon, 42.5% two cotyledons, 16.8% three cotyledons, 7.8% four cotyledons, 1.8% five cotyledons, and 8.2% jar shaped cotyledon. In addition, ABA treatment indicated an improvement of the somatic embryo with normal cotyledon (65.3%). ABA was important role to the high production of normal somatic embryos. Two cotyledon embryos showed germinability 77.8%. However the germinability of somatic embryos with anomalous cotyledons was prominently low: One cotyledon, 62.5%; three cotyledons, 43.3%; four cotyledons, 60%; five cotyledons, 50% and jar shaped cotyledon, zero%. Thus, germinability was essentially, inversely proportional to cotyledon number.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.1 s.12
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• pp.38-46
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• 2007

In this paper an X-band low phase noise HBT oscillator using a planar type MMIC resonator is designed. The chip area of the proposed resonator shows a quarter of the conventional hair-pin resonator using distributed transmission lines. The measurement results show oscillation frequency of 8.295 GHz, the power output of 4.8 dBm, and phase noise characteristic of -106.8 dBc/Hz and -121.7 dBc/Hz at 100 kHz and 1 MHz offset frequencies respectively.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.1
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• pp.234-243
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• 1995

An arry circuit is designed for parallel computation of vector-radix 2-D discrete cosine transform (VR-FCT) which is a fast algorithm of DCT. By using a 2-D array of processing elements (PEs), the butterfly structure of the VR-FCT can be efficiently implemented with high condurrency and local communication geometry. The proposed implementation features architectural medularity, regularity and locality, so that it is very suitable for VLSI realization. Also, no transposition memory is required. The array core for (8$\times$8) 2-D DCT, which is designed usign ISRC 1.5.mu.m N-Well CMOS technology, consists of 64 PEs arranged in (8$\times$8) 2-D array and contains about 98,000 transistors on an area of 138mm$^{2}$. From simulation results, it is estimated that (8$\times$8) 2-D DCT can be computed in about 0.88 .mu.sec at 50 MHz clock frequency, resulting in the throughput rate of about 72${\times}10^[6}$ pixels per second.

• Journal of Plant Biology
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• v.36 no.4
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• pp.407-413
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• 1993

해녀콩(Canavalia lineata L. DC) 잎에서 유도한 캘러스를 pH 8인 완충용액에 한 시간 동안 처리하면 pH 6에서 보다 arginase의 활성이 약 두 배로 증가했다. 캘러스에서 얻은 arginase의 조효소액을 Sephacryl S-200 컬럼에서 분획하면 분자량이 각각 380 kD과 179 kD으로 나타났는데 분자량이 큰 arginase의 분획은 pH 8 처리구에서 각각 상대적으로 많이 나타났다. 그리고 pH 6에 0.5 mM Mn2+를 첨가하였을 때도 380 kD arginase의 분획이 크게 나타났으며, pH 6 처리에서 얻은 179 kD arginase 분획에 pH 8 처리를 하면 380 kD 분획으로 쉽게 전이될 수 있었다. pH 6 처리 후 추출한 arginase는 Mn2+의 첨가로 활성이 크게 증가하여 pH 8 처리 후 추출한 arginase와 비슷한 활성을 보이나, pH 8 처리 후 추출한 arginase는 Mn2+의 첨가로 더 이상의 활성증가를 보이지 않았다. Mn2+이 없는 조건에서 두 arginase의 Km값과 Vmax를 조사한 결과, 380 kD arginase는 22 mM과 1.61 $\mu$mole urea.min-1.mg-1 protein, 그리고 179 kD arginase는 30 mM과 0.79 $\mu$mole urea.min-1.mg-1 protein으로 측정되었다.

• KIPS Transactions on Computer and Communication Systems
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• v.7 no.12
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• pp.289-294
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• 2018

This paper proposes an implicit d-ary priority queue, called AM(d)-heap that is a generalized version of AM-heap, in which insert operation takes constant amortized time and remove operation takes O(logn) time. According to our experimental results, the best performance was shown when d is 4 or 8. Also, AM(d)-heap is about 1.5~1.8 times faster than the postorder heap.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.194-199
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• 2002

Many oxidative metabolites of tetrahydrocannabinols (THCs), active components of marijuana, were pharmacologically active, and 11-hydroxy-THCs, 11-oxo-${\Delta}^8$-THC, 7-oxo-${\Delta}^8$-THC, 8$\beta$, 9$\beta$-epoxyhexahydrocannabinol (EHHC), 9$\alpha$, l0$\alpha$-EHHC and 3'-hydroxy-${\Delta}^9$-THC were more active than THC in pharmacological effects such as catalepsy, hypothermia and barbiturate synergism in mice. Cannabidiol (CBD), another major component, was biotransfomred to two novel metabolites, 6-hydroxymethyl-${\Delta}^9$-THC and 3-pentyl-6, 7, 7a, 8, 9, lla-hexahydro-I, 7-dihydroxy-7, 1O-dimethyldibenzo[b, d]oxepin (PHDO) through 8R, 9-epoxy-CBD and 85, 9-epoxy-CBD, respectively. Both metabolites exhibited some pharmacological effects comparable to d9 - THe. Cannabinol (CBN), the other major component, was mainly metabolized to ll-hydroxy-CBN by hepatic microsomes of animals including humans. The pharmacological effects of the metabolite were higher than those of CBN demonstrating that II-hydroxylation of CBN is metabolic activation pathway of the cannabinoid as is the case in THCs. Tolerance and reciprocal cross-tolerance developed to pharmacological effects d8 - THC and ll-hydroxy-d8-THC , and the magnitude of tolerance development produced by the metabolite was significantly higher than that by d8-THC. The results indicate that ll-hydroxy-d8-THC has an important role not only in the pharmacological effects but also its tolerance development of d8 - THe. THCs and their metabolites competed to the specific binding of CP-55, 940, an agonist of cannabinoid receptor, to synaptic membrane from bovine cerebral cortex. The Ki value of THCs and their metabolites were closely paralleled to their pharmacological effects in mice. A novel cytochrome P450 (cyp2c29) was purified and identified as a major enzyme responsible for the metabolic activation of d8-THC at the II-position in the mouse liver. cDNA of CYP2C29 was cloned from a mouse cDNA library and its sequence was determined. The oxidation mechanism of THC by cyp2c29 was proposed.