• 약학회지
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• 제49권2호
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• pp.134-139
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• 2005

Warfarin is a widely used oral anticoagulant agent used to treat thromboembolic disease. The purpose of this study was to develop the efficient assay method of warfarin sodium i n human plasma and to assess the pharmacokinetic profile of the warfarin in healthy Korean volunteers. The pharmacokinetics of warfarin administered orally was evaluated after a dose of 10 mg. Warfarin in plasma was assayed using a specific HPLC method with UV absorbance at 304 nm. AUC was 46.33${\pm}9.95{\mu}g/ml.hr$, $C_{max}$ $1.22{\pm}0.22{\mu}g/ml, $T_{max}$$2.50{\pm}1.41$ hr and half-life $43.49{\pm}4.33$ hr. $T_{max}$ was slightly shorter than that in Caucasian (3~9 hr), whereas the half-life was longer than that in Caucasian (10~45 hr, mean: 36 hr). These results suggest that warfarin may have a longer duration in Korean than in Caucasian.

• 한국식품과학회지
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• 제20권2호
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• pp.245-251
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• 1988

Thermolysin 을 Dowex MWA-1에 10% glutaraldehyde로 고정화하였으며, 이 고정화 thermolysin을 사용하여 연속적응유(連續的凝乳)를 행(行)하였다. Thermolysin의 고정화수율(固定化收率)은 25%이었다. 고정화 thermolysin은 1/200M $Ca^{++}\;ion$의 존재하에서 $60^{\circ}C$의 고온에서도 안정하였으며 이 온도에서의 half-life는 16일이었다. 원료 milk를 pH 7.0이 되도록 조정하여 $55^{\circ}C$로 유지된 고정화 thermolysin column을 통과 시 켜 분해시킨 후, Streptococcus cremoris를 접종하여 응유(凝乳)시켜 curd를 얻었으며, 이렇게 하므로써 미생물오염이 방지될 수 있었으며 연속적응유를 효과적으로 행할 수 있었다. 고정화 thermolysin을 사용하여 얻은 cheddar type의 cheese는 rennet을 사용한 전통적인 방법으로 만든 cheese 와 거의 비슷하였다.

• 한국환경농학회지
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• 제6권1호
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• pp.31-37
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• 1987

수도재배환경중(水稻栽培環境中) carbofuran의 흡수(吸收), 이행(移行) 및 잔류양상(殘留樣相)을 구명(究明)하기 위하여 소형수도재배구(小型水稻栽培區)를 이용(利用), carbofuran 입제(粒劑)를 2수준(水準)으로 살포(撒布)하고 시기별(時期別)로 수질(水質), 수도체(水稻體),토양(土壤) 및 수확물중(收穫物中) 잔류수준(殘留水準)을 조사(調査)한 결과(結果)는 다음과 같다. 수면살포(水面撒布)한 carbofuran 입제(粒劑)는 빠른 속도(速度)로 용출(溶出)되어 수질중(水質中) carbofuran 농도(濃度)는 처리(處理) 1일이내(日以內)에 최고치(最高値)에도 달하였다. 용출(溶出)된 carbofuran은 수도체(水稻體)로 흡수(吸收), 이행(移行)되어 처리(處理) 1∼3일(日) 후(後)에 최고치(最高値)에 도달하였으며 그 이후(以後) 완만한 감소(減少) 경향(傾向)을 보였다. 수질중(水質中) carbofuran의 반감기(半減期)는 4일(日)이었고 토양중(土壤中)에서의 반감기(半減期)는 처리수준(處理水準)에 따라 8∼12일(日)이었다. 수확물중(收穫物中) carbofuran 잔류량(殘留量)은 현미(玄米)의 경우 0.01∼0.02ppm이었으며 볏짚에서는 0.37∼0.07ppm의 범위(範圍)였다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제16권1호
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• pp.12-18
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• 2011

To investigate the natural reduction characteristics of radon with a short half-life (3.82 day) in drinking Qgroundwater, we analyzed the changes of radon concentrations of groundwater, waters in storage tanks, and tap waters from the small-scale groundwater-supply systems (N = 301) by LSC (Liquid Scintillation Counter). We also analyzed the concentrations of uranium (half-life 4.5 billion years) in the waters by ICP/MS to compare with natural reduction of radon concentration. The radon concentrations of 68 groundwater-supply systems occupying 22.6% of the total samples exceeded the US EPA's Alternative Maximum Contaminant Level (AMCL : 4,000 pCi/L), with the average radon concentration of 7,316 pCi/L (groundwaters), 3,833 pCi/L (tank waters) and 3,407 pCi/L (tap waters). Compared to the radon levels of pumped groundwaters, those of tank and tap waters naturally reduced significantly down to about 50%. Especially, in case of 29 groundwater-supply systems with the groundwater radon concentrations of 4,000~6,000 pCi/L, average radon concentrations of the tank and tap waters naturally decreased down to the AMCL. Therefore this study implies that radon concentrations of drinking groundwater can be effectively reduced by sufficient storage and residence in tanks.

• 방사선산업학회지
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• 제9권4호
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• pp.193-198
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• 2015

Most of targeted therapies block the action of certain enzymes, proteins, or other molecules involved in the growth and spread of cancer cells to produce its cytotoxic effect. Either small molecule drugs or monoclonal antibodies are mostly used in targeted therapies. Unfortunately, targeted therapy has a certain degree of unwanted side effect like other cytotoxicity inducing chemotherapies. To overcome and to reduce unwanted side effects during a cancer therapy, recently radiopeptide therapies has got the worlds' attraction for the tumor targeting modalities due to its beneficial effect on less side effect compared to cytotoxic chemotherapies. Among radiopeptide therapies, $^{177}Lu$-DOTATATE is a major modality as an effective one invented so far in treating neuroendocrine tumor (NET) and it has been in clinical trials at least one decade. Although it does have rather effective therapeutic effect on NET, it has less effective in rather large solid tumor. There are many ways to improve or increase therapeutic effect of radiopeptide are a finding the potent small molecules to target the tumor site selectively, or a labeling with radioisotope of emitting high energy, or an improving its biological half-life by introducing different moieties to increase lipophilicity. Present study was focus to increase a biological half-life of radio somatostatin which will target the somatostatin receptor by altering the bifunctional chelator (BFCA) by introducing lipophilic moiety to the somatostatin, which would make the labeled peptide stay longer in the tumor site and thus it can intensify the therapeutic effect on tumor cell itself and around tissues.

• Animal cells and systems
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• 제14권3호
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• pp.147-154
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• 2010

It is well-established that phosphoinositide 3-kinase (PI3-kinase) regulates myogenesis by inducing transcription of myogenin, a key muscle regulatory factor, at the initiation of myoblast differentiation. In this study, we investigated the role of PI3-kinase in cells that have committed to differentiation. PI3-kinase activity increases during myogenesis, and this increase is sustained during the myogenic process; however, its function after the induction of differentiation has not been investigated. We show that LY294002, a PI3-kinase inhibitor, blocked myoblast fusion even after myogenin expression initially increased. In contrast to the inhibitory effects of LY294002 on myogenin mRNA levels during the initiation of differentiation, LY294002 blocked the accumulation of myogenin protein without affecting its mRNA level after differentiation was induced. Treatment with cycloheximide, a translation inhibitor, or actinomycin D, a transcription inhibitor, indicated that the stability of myogenin protein is lower than that of its mRNA. LY294002 inhibited the activities of several important translation factors, including eukaryotic elongation factor-2(eEF2), by altering their phosphorylation status. In addition, LY294002 blocked the incorporation of [$^{35}S$]methionine into newly synthesized proteins. Since myogenin has a relatively short half-life, LY294002-mediated inhibition of post-transcriptional processes resulted in a rapid depletion of myogenin protein. In summary, these results suggest that PI3-kinase plays an important role in regulating the expression of myogenin through post-transcriptional mechanisms after differentiation has been induced.

• Korean Journal of Chemical Engineering
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• 제35권11호
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• pp.2207-2219
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• 2018

Activated carbon (AC) was synthesized from Phoenix dactylifera stones and then modified by $CoFe_2O_4$ magnetic nanocomposite for use as a Cr(VI) adsorbent. Both $AC/CoFe_2O_4$ composite and AC were fully characterized by FTIR, SEM, XRD, TEM, TGA, and VSM techniques. Based on the surface analyses, the addition of $CoFe_2O_4$ nanoparticles had a significant effect on the thermal stability and crystalline structure of AC. Factors affecting chromium removal efficiency like pH, dosage, contact time, temperature, and initial Cr(VI) concentration were investigated. The best pH was found 2 and 3 for Cr adsorption by AC and $AC/CoFe_2O_4$ composite, respectively. The presence of ion sulfate had a greater effect on the chromium sorption efficiency than nitrate and chlorine ions. The results illustrated that both adsorbents can be used up to seven times to adsorb chromium. The adsorption process was examined by three isothermal models, and Freundlich was chosen as the best one. The experimental data were well fitted by pseudo-second-order kinetic model. The half-life ($t_{1/2}$) of hexavalent chromium using AC and $AC/CoFe_2O_4$ magnetic composite was obtained as 5.18 min and 1.52 min, respectively. Cr(VI) adsorption by AC and $AC/CoFe_2O_4$ magnetic composite was spontaneous and exothermic. In general, our study showed that the composition of $CoFe_2O_4$ magnetic nanoparticles with AC can increase the adsorption capacity of AC from 36 mg/L to 70 mg/L.

• Imaging Science in Dentistry
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• 제53권3호
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• pp.217-220
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• 2023

Purpose: This pilot study was conducted to evaluate half-value layer (HVL) measurements obtained using a semiconductor dosimeter for intraoral radiography. Materials and Methods: This study included 8 aluminum plates, 4 of which were low-purity (less than 99.9%) and 4 high-purity (greater than 99.9%). Intraoral radiography was performed using an intraoral X-ray unit in accordance with the dental protocol at the authors' affiliated hospital: tube voltage, 60 kVp and 70 kVp; tube current, 7 mA; and exposure time, 0.10 s. The accuracy of HVL measurements for intraoral radiography was assessed using a semiconductor dosimeter. A simple regression analysis was performed to compare the aluminum plate thickness and HVL in relation to the tube voltage (60 kVp and 70 kVp) and aluminum purity (low and high). Results: For the low-purity aluminum plates, the HVL at 60 kVp (Y) and 70 kVp (Y) was significantly correlated with the thickness of the aluminum plate (X), with Y=1.708+0.415X (r=0.999, P<0.05) and Y=1.980+0.484X (r=0.999, P<0.05), respectively. Similarly, for the high-purity aluminum plates, the HVL at 60 kVp (Y) and 70 kVp (Y) was significantly correlated with the plate thickness(X), with Y=1.696+0.454X (r=0.999, P<0.05) and Y=1.968+0.515X (r=0.998, P<0.05), respectively. Conclusion: This pilot study examined the relationship between aluminum plate thickness and HVL measurements using a semiconductor dosimeter for intraoral radiography. Semiconductor dosimeters may prove useful in HVL measurement for purposes such as quality assurance in dental X-ray imaging.

• 대한방사성의약품학회지
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• 제7권2호
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• pp.147-152
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• 2021

C-11 Radiolabeled amino acid-based radiopharmaceuticals such as [¹¹C]MET for brain tumor PET imaging have limitations due to their short half-life (20 min). F-18 radiolabeled amino acid derivatives have been developed to overcome for the short half-life, one of which is [¹⁸F]FET. Brain tumor imaging using [¹⁸F]FET showed high uptake in tumor region and no non-specific uptake in inflammatory tissue, which was useful in discriminating the difference between inflammation and tumor especially. In this study, [¹⁸F]FET was synthesized using an automatic synthesis module and quality tests were carried out including enantiomeric purity analysis with reference compounds. Radiochemical yield was 50.3 ± 4.9% (n=7, decay-corrected) with molar activity of 76 ± 17 GBq/mmol. The radiochemical purity of >99%. Enantiomeric purity of [¹⁸F]FET using chiral HPLC analysis showed >99%, which was confirmed by co-injection with the L-FET and D-FET authentic standards. [¹⁸F]FET was prepared with high radiochemical yield and molar activity including no racemate mixture.

• Asian-Australasian Journal of Animal Sciences
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• 제9권4호
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• pp.461-464
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• 1996

The data on milk yield of 1837 healthy dairy cows of different genetic groups raised in Central Cattle Breeding and Dairy farms, Savar, Dhaka for the period from 1978 to 1992 were analyzed from first to 6th lactation. The mean (SE) milk yields of 100 days, 305 days, total lactation and total life time ($928{\pm}48.6kg$, $2,188{\pm}201.81kg$, $2,661{\pm}385.46kg$ and $11,134{\pm}2,916kg$) respectively, were in pure bred Friesian found to be highest among all genetic groups. The corresponding means in indigenous cows, $334{\pm}12.92kg$, $946{\pm}64.44kg$, $635{\pm}16.31kg$ and $3,934{\pm}402.21kg$ were the lowest. Among the $F_1$, $F_2$ and $F_3$ cross-breds, the $F_1$ half bred Friesian showed the highest performance in milk yield. The half bred Friesian in successive generations yielded low milk. Similar trend was obtained incase of cross-bred with other breeds such as Jersey, Sindhi and Sahiwal. From the over all results, it can be concluded that the performance in respect to milk yield of pure bred Friesian and their $F_1$ half bred with indigenous and Sahiwal were superior over the $F_2$ or $F_3$ cross-breds between Fresian and any other breed irrespective of proportion of blood. The performance in respect to production of indigenous local cow was found to be almost similar with that of Sahiwal breed.