• Polymer(Korea)
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• v.28 no.4
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• pp.335-343
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• 2004

Carmustine (l,3-bis(2-chloroethyI)-1-nitrosourea, BICNU) used as antineoplastic drug for the treatment of brain tumor is not appropriate for the long term delivery, because it has short biological half life. Therefore, poly(D,L-lactide-co-glycolide) (PLGA) is useful as drug carrier for the long term delivery due to bulk erosion property. Glycolide monomer is applied to release of BICNU owing to non-toxic and monomeric components after biodegradation of PLGA. In this study, BICNU-loaded PLGA wafers with or without glycolide monomer were fabricated by conventional direct compression method for the sustained release of BICNU. These wafers were observed for their release profiles of BICNU and degradation rates by SEM, NMR, and GPC. Furthermore, we make multi-layer wafers and compare them with release profiles of conventional wafer. From these results, drug release of BICNU-loaded PLGA wafers was increased with increasing the glycolid monomer contents. We confirmed that glycolide monomer and BICNU contents in barrier-layer influenced the drug release profiles and degradation rate.

• Journal of Plant Biology
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• v.35 no.2
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• pp.107-116
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• 1992

The roles of RNA- and protein-synthesis and $H^{+}$ excretion in 1AA ($10\;\mu\textrm{M}$)-induced elongation were investigated using abraded hypocotyl segments of sunflower (Helianthus annuus L.). The response of elongation initiated about 13 min after IAA treatment. Removal of cuticle, acting as diffusion barrier for inhibitors, by mechanical abrasion of hypocotyl segments enhanced the effect of inhibitors markedly, but the degree of abrasion for the saturated effect of inhibition was different among inhibitors. The elongation induced by 1M was completely inhibited when cycloheximide ($10\;\mu\textrm{M}$) was applied to abraded hypocotyl segments as shortly as 4 min before the onset of the growth response (= 10 min after administration of IAA). Cordycepin ($200\;\mu\textrm{M}$) prevented completely 1AA-induced elongation when applied as shortly as 19 min before the onset of the growth response (=5 min before administration of 1AA). Vanadate (1 mM) inhibited both lAA-induced elongation and medium acidification via lAA-induced $H^{+}$ excretion to apoplast. Cycloheximide and cordycepin also prevented lAA-induced $H^{+}$ excretion strongly. However, inhibition by cycloheximide of lAA-induced elongation was not alleviated by acidifying the cell wall to pH 4.5. The results indicate that, a few minutes before the initiation of growih, protein synthesis is demanded for the initiation of 1AA-induced elongation and the $H^{+}$ excretion to cell wall, and that the H+ excretion, even though it may be necessary for elongation, does not seem to bring about acid growth simply through acidifying cell wall.l wall.

• Journal of Aquaculture
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• v.9 no.1
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• pp.3-10
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• 1996

Ovulation of maturing female yellow puffer, Takifugu obscrus, was induced by using single injection of human chorionic gonadotropin (HCG) or gonadotropin releasing hormone-analogue (GnRH-A) $des-Gly^{10}[D-Ala^6]$ GnRH-ethylamide plus pimozide. The response was evaluated using the fertilization and embryo-formation rate after insemination and the gonadotropin (GTH) level in blood plasma using radioimmunoassay. In the fertilization and embryo-formation, maximal effects were recorded by using 1,000 IU/kg HCG or $10\;{mu}g/kg$ GnRH-A plus 5 mg/kr pimozide. Pimozide (1, 5 mg/kg) or GnRH-A treatment alone was not effective in elevation of GTH level, however combinations of these treatments were particularly effective. Injection of dopamine blocked the rapid elevation of plasma GTH levels of blood. These data suggest that yellow puffer secrete GnRH and gonadotropin-releasing-inhibiting factor during the spawning or the other period.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.331.1-331.1
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• 2016

내부지름이 2.0 mm 이하인 PTFE와 PE 튜브에 진공장치를 이용하여 튜브 내부의 압력을 감압하여 진공상태를 형성하였다. 진공기밀 후에 반응성 가스를 인입하여 튜브 외부에 장착된 전극을 통하여 고전압의 AC 전압을 인가하여 튜브 내부에 선택적으로 유전체 장벽 방전을 유도하였다. 본 연구에서는 유전율이 3.0 이하로 낮은 PTFE와 PE 튜브에 유전체 장벽방전이 유도될 때 나타나는 전압과 전류의 파형을 분석하여 방전의 개시와 방전의 형태를 조사하였다. 주파수 40 kHz인 AC 전원(PEII, Advanced Energy)과 Loadmatch 모듈을 이용하여 4 kV 이하의 전압을 인가하여 플라즈마 방전 유도하였다. 튜브에 인가고전압 프로브와 전류 프로브를 이용하여 오실로스코프를 I-V 분석을 실시하였고, 실험 결과 대기압 방전에서 유도되는 유전체 장벽방전의 I-V 특성과 달리 방전의 형태가 유전체장벽방전과 글로우방전이 혼합된 형태로 나타났다. 또한 유전체 장벽방전을 통해 튜브 내부에 형성되는 플라즈마에 대한 분석으로 OES 광분석을 실시하여, 방전 시간과 전압 변화에 따른 고분자 표면으로부터 방출되는 활성종에 대한 분석을 실시하였다.

• Korean Journal of Optics and Photonics
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• v.3 no.2
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• pp.137-140
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• 1992

레이저 플라즈마에서 방출되는 X-선의 이용이 크게 발전될 것이 예측되나, X-선에 대한 광속의 시준화, beam homogenizing, 광속축소, 광유도 등이 어려워서 예상한 바 큰 발전이 이루어지지 못하고 있다. 이 난제를 해결할 수 있는 가능성이 모세관 광유도광학에서 엿보이기에 여기에 소개하여 광학, 레이저 플라즈마 등을 연구하는 회원들의 관심을 끌고자 한다.

• Journal of the Korean Orthopaedic Association
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• v.56 no.5
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• pp.398-403
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• 2021

Purpose: A biopsy is needed to diagnose soft tissue tumors. However, it is extremely difficult to pinpoint the site of a tumor due to the heterogeneity of sarcomas. Thus, even when an open biopsy is conducted, it is difficult to diagnose a soft tissue tumor. In such cases, an ultrasound (US)-guided biopsy is used to improve the diagnostic accuracy. This study evaluated the accuracy of US-guided biopsy for a diagnosis of soft tissue tumors found initially in a magnetic resonance (MR) perfusion and assessed the availability of positron emission tomography-computed tomography (PET-CT) for a diagnosis of soft tissue tumors. Materials and Methods: From January 2014 to December 2018, the US-guided biopsy was performed on 152 patients with a suspected soft tissue tumor found in an MR perfusion and 86 cases were definitively diagnosed with a soft tissue tumor. The accuracy of the US-guided biopsy was assessed retrospectively. Among the 86 cases, only MR perfusion was used before the biopsy in 50 cases, while both MR perfusion and PET-CT was conducted on 36 cases. The accuracy was analyzed to determine if the PET-CT could improve the precision of a biopsy. Results: From 86 cases, 34 out of 50 cases, in which only MR perfusion had been conducted, matched the result of the definitive diagnosis and the US-guided biopsy. 32 out of 36 cases, in which both PET-CT and MR perfusion were conducted, matched the definitive diagnosis and the US-guided biopsy. These results show significant differences in the accuracy of US-guided biopsy. In the case of soft tissue sarcomas, 6 out of 12 cases, in which only MR perfusion had been conducted, matched the result of the definitive diagnosis and the US-guided biopsy. 17 out of 18 cases, in which both PET-CT and MR perfusion were conducted, matched the definitive diagnosis. Moreover US-guided biopsy also showed significant differences in the accuracy of US-guided biopsy. Conclusion: In diagnosing soft tissue tumors, a US-guided biopsy is a well-known tool for its high accuracy. However, the heterogeneity of sarcoma makes it difficult to locate the exact site for a biopsy using only MR perfusion. Thus, the use of PET-CT will meaningfully improve the accuracy of a diagnosis by precisely targeting the site for the US-guided biopsy.

• Journal of Life Science
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• v.16 no.2 s.75
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• pp.315-322
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• 2006

FS11052, a novel microbial metabolite from Streptomyces spp. was identified as a small molecular substance and shown inhibition activities for the release of neurotransmitter from rat hippocampal neuron and PC12 cells. FS11052 is an inhibitor of tritiated norepinephrine ($[^3H]-NE$) release in high $K^+$ buffer solution containing ionomycin, indicating that FS11052 inhibits neurotransmitter release after the influx of $Ca^{2+}$ ions. When examined the effect of FS11052 on glucuronidase release from guinea pig neutrophils, FS11052 inhibited glucuronidase release: when treated with $5{\mu}g/ml$ of FS11052, which was not induced cellular cytotoxicity. The fact that the glucuronidase release in neutrophil and norepinephrine release in neuron was inhibited suggests the similarity in the locations and the mechanisms of FS11052 action targets. When treated with $5{\mu}g/ml$ of FS11052, $[^3H]-NE$ release and neurite extension for both rat hippocampal neurons and PC12 cells were prevented. These observations of FS11052 functioning as an inhibitor of neurotransmitter release suggest that FS11052 has an important role in synaptic transmission in neuron.

• Analytical Science and Technology
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• v.14 no.4
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• pp.324-330
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• 2001

For the analysis of S, P and Zn in lubricating oil, microwave digestion method was studied by using inductively coupled plasma-atomic emission spectrometry(ICP-AES). Lubricating oil was completely decomposed with nitric acid or a mixture of nitric acid and hydrogen peroxide using and closed microwave digestion system. Digestions are completed within 50 min, a factor of at least 3~4 times faster than for the conventional digestion. A gradual heating program operated by the pulsed mode was found suitable for decomposing the lubricating oil matrix safely. The proposed method of digestion gave relative standard deviations(RSD) less than 3% for the elements determined.

• Analytical Science and Technology
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• v.14 no.1
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• pp.21-27
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• 2001

In this work, analytical performance of a laboratory built double membrane desolvator (DMD) was studies using perfluoroalkoxy (PFA) nebulizer and microconcentirc nebulizer (MCN) in inductively coupled plasma atomic emission spectrometry. Compared with MCN, PFA nebulizer coupled to DMD showed similar analytical sensitivity for aqueous solution and better sensitivity for isopropyl alcohol. Since PFA resisted various acids, HCI, $H_2SO_4$ and HF solution were analyzed with less than 2% RSD. Rinse-out time for the signal reduction to 1% was obtained to be 35 s for PFA but about 45 s for MCN.

• Analytical Science and Technology
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• v.7 no.3
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• pp.253-260
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• 1994

Analytical characteristics of low power-low flow inductively coupled plasma-atomic emission spectometry(ICP-AES) has been studied. Although the net intensity of the low power ICP is lower than the moderate power ICP, the signal to background ratio becomes higher since the background intensity decreases with decreasing the RF power. The detection limit of the low power ICP is comparable with that of the moderate power ICP. The dynamic range of the calibration curve of the low power ICP is $10^4{\sim}10^5$. The ionization interferences by alkali metals increase with increasing the carrier gas flow rate, but the effects are not varied significantly with the RF power.