• Biomolecules & Therapeutics
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• 제14권2호
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• pp.90-95
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• 2006

CKD-602 exerts its antitumor effect via inhibition of topoisomerase I in cancer cells. Multicellular spheroid (MCS) and Multicellular layers (MCLs) are known as in vitro 3-dimensional models which closely represent tumor conditions in vivo. In order to investigate the potential of CKD-602 against human colorectal tumors, we evaluated the anti-proliferative activity and penetration ability of CKD-602 in MCS and MCL cultures of DLD-l human colorectal cancer cells, respectively. The maximum effects($E_{max}$) induced by CKD-602 were significantly lower in MCS compared to monolayers (48% vs 92%). With prolonged drug exposure, the $IC_{50's}$ of CKD-602 decreased to $23.5{\pm}1.0nM$ in monolayers after 24 h exposure and $42.3{\pm}1.7nM$ in MCS after 6 days, respectively. However, no further increase in effect was observed for exposure time longer than growth doubling time (Td) in both cultures. Activity of CKD-602 was significantly reduced after penetration through MCL and also with cell-free insert membrane. In conclusion, CKD-602 showed significantly decreased anti-proliferative activity in 3D cultures (MCS) of human colorectal cancer cells. Tumor penetration of CKD-602 could not be determined due to loss of activity after penetration through cell free insert membrane, which warrants further evaluation using a modified model.

• 한국학교수학회논문집
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• 제16권1호
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• pp.241-263
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• 2013

본 연구의 목적은 문제해결 과정에서 나타나는 학생들의 추론 특성을 알아보는 것이다. 이를 위해, 다섯 명의 고등학생들을 연구참여자로 선정하여 이들에게 다양한 전략적 접근이 가능한 개방형 과제를 부과한 후, 그들의 문제해결 과정을 관찰하였다. 문제해결 과정을 그들이 작성한 답안지와 연계하여 분석함으로써 다음을 확인하였다. 첫째, 학생들은 과제를 접할 때 문제이해 없이 성급하게 계산을 시도하는 경향이 있다. 둘째, 학생들은 스스로 선택한 전략의 결과에 대해 수학적 근거를 고려하여 정당화하기보다 정답을 구했는지에 대해 더 관심이 많다. 셋째, 문제해결에 필요한 두 가지 이상의 조건을 동시에 고려하지 못하는 경향이 있다. 넷째, 학생들은 과제와 관련된 선행지식을 활용하는데 능숙하지 못하다. 다섯째, 학생들은 지나친 일반화로 문제해결에 어려움을 겪을 수 있다.

• Archives of Reconstructive Microsurgery
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• 제3권1호
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• pp.64-71
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• 1994

해부학적으로 족부는 주위에 이용할 수 있는 연주 조직이 별로 없을 뿐 아니라 이용할 수 있더라도 크기가 제한되어 있으므로 광범위한 연부조직 결손시 이의 복원이 어렵다. 광범위하고 오염된 족부의 창상을 재건시 이상적인 조직의 조건으로서는 감염에 잘 견디고, 가능한한 원래의 모양 및 크기에 가깝게 복원해야 하며, 적절한 감각이 있어야 하고, 끊임없는 마찰력과 체중 부하에 잘 견뎌야 할 것이다. 미세혈관술을 이용한 유리조직이식은 비교적 위와같은 장점들을 제공할 수 있다. 저자들은 최근 약 4년간 외상과 전기화상 및 화상후 후유증으로 인하여 족배부, 발꿈치, Achilles건, 족저부등에 광범위한 결손 및 변형이 있었던 환자 21예에서 미세혈관술을 이용하여 Fasciocutaneous, musulocutaneous, muscle with skin graft 등으로 족부를 재건하여 추적중에 있으며 현재까지 관찰된 결과 및 장점, 단점과 문제점들을 보고하는 바이다.

• 대한수학교육학회지:수학교육학연구
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• 제24권1호
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• pp.1-27
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• 2014

본 연구는 개방형 기하 문제에서 드래깅 활동을 통해 나타난 중학교 3학년 학생들의 사고 과정을 가추법, 귀납법, 연역법을 중심으로 분석하였다. 본 연구의 결과는 다음과 같다. 첫째, 학생들은 자신의 가설을 도입하기 위해 가추법을 사용하고, 다양한 사례를 통해 가설을 일반화하기 위해 귀납법을 사용하며, 가설의 근거를 설명하기 위해 연역법을 사용하였다. 둘째, '임의적 드래깅'과 '안내된 드래깅'은 학생들의 가추 과정에서 가설을 마련하는데 도움이 되었으며, '드래깅 검증'은 학생들의 귀납 과정에서 가설을 확신하고 일반화하는 데 사용되었다. 셋째, 학생들은 도형을 고정된 것으로 생각하거나 종속 관계나 경로의 개념을 쉽게 인식하지 못하거나 개연적 추론에서 연역법으로 부드럽게 나아가지 못하거나 순환논리에 빠지는 인지적 어려움을 겪었다.

• Journal of Preventive Medicine and Public Health
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• 제53권3호
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• pp.180-188
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• 2020

Objectives: The Short Form 36 (SF-36) questionnaire is increasingly being used to measure health-related quality of life (HRQoL) in Indonesia. However, evidence that it is valid for use in Indonesian adults is lacking. This study assessed the validity and reliability of the SF-36 in Indonesian middle-aged and older adults. Methods: Adults aged 46-81 years (n=206) in Yogyakarta, Indonesia completed the SF-36, another measure of HRQoL (the EuroQoL visual analogue scale [EQ-VAS]), and measures assessing their demographic characteristics. Fifty-four percent (n=121) completed the SF-36 measure again 1 week later. Confirmatory factor analysis was conducted to confirm the factor structure of the SF-36. Internal consistency reliability was estimated using Cronbach's alpha, and test-retest reliability was assessed using intraclass correlations. Convergent and discriminant validity were assessed by computing correlations among SF-36 subscales, between subscales and the 2 component scores, and between component scores and EQ-VAS scores. Results: Most scaling assumptions were met. The hypothetical factor structure fit the data poorly (root mean square error of approximation [RMSEA]=0.108) and modification was required for a good fit (RMSEA=0.060). Scores on all subscales demonstrated acceptable internal consistency (α>0.70) and test-retest reliability (r>0.70). Divergent validity was supported by weak to moderate interscale correlations (r=0.19 to 0.64). As expected, the 2 summary scores were moderately to strongly correlated with the EQ-VAS (r>0.60). Conclusions: The findings adequately support the use of SF-36 in Indonesian middle-aged and older adults, although the optimal algorithm for computing component scores in Indonesia warrants further investigation.

• Toxicological Research
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• 제6권2호
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• pp.159-166
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• 1990

The ability of many toxigenic fungi to invade and develop in a wide variety of raw ingredients of human diet renders human exposure to mycotoxing very difficult to avoid. Most of the energy-rich commodities, such as cereal grains, oil seeds, tree nuts, and dehydrated fruits, are susceptible to mycotoxin contamination. Mycotoxins therefare have been recognized as an important class of hazardous substances in the human food chain. Although human exposure to mycotoxins is largely through ingestion, inhalation and skin contact may also be significant under conditions other than consumption of foods. Human ingestion of mycotoxins is due to consumption of contaminated dietary ingredients and the edible tissues and products of domestic animals that have been exposed to mycotoxins in moldy feed. Large scale acute human mycotoxicoses, such as ergotism in France, alimentary toxic aleukia in Russia, yellow rice syndrome in Japan, endemic nephropathy in Balkan countries, and acute aflatoxin poisonings in India and Taiwan, have been well documented, indicating that mycotoxicosis is a global problem. In some incidents, hundreds of victims were killed and many more became seriously ill. The mycotoxins that have been implicated in the etiology of these human diseases include aflatoxins, citreoviridin, cyclopiazonic acid, ergot alkaloids, moniliformin, ochratoxin A, trichothecenes, tenuazonic acid, and zearalenone. Among these, aflatoxins have been also implicated in the etiology of human primary liver cancer in those high-incidence countries in Africa and southeast Asia. It is well recognized that cause-effect relationship between mycotoxins and human diseases is very difficult to establish, especially for the cancer connection. Careful risk assessment must be performed to determine whether a mycotoxin indeed warrants costly regulatory actions.

• Journal of Pharmaceutical Investigation
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• 제37권5호
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• pp.305-309
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• 2007

Arsenic compounds have been used to treat various diseases including cancer in oriental medicine. Arsenic trioxide ($As_2O_3,\;Trisenox^{(R)}$) has been used for the treatment of leukemia and its anti-solid tumor activity has also been reported recently. Tetra-arsenic oxide ($As_4O_6,\;TetraAs^{(R)}$) is a newly developed arsenic compound which has shown an anticancer activity in some human cancer cell lines. The purpose of this study was to evaluate the anti-gastric cancer potential of TetraAs and to search for an agent with synergistic interaction with TetraAs against human gastric cancers. We analysed anti-proliferative effect of TetraAs when given alone and in combination with other chemotherapeutic agents such as 5-FU, paclitaxel, and cisplatin in SNU-216, a human gastric cancer cell line. The $IC_{50}$ of these 4 anti-cancer drugs ranged from 5.8 nM to $7.5\;{\mu}M$ with a potency rank of order paclitaxel>TetraAs>cisplatin>5-FU. TetraAs showed 10-fold greater potency than 5-FU and cisplatin at the same effect level of $IC_{50}$. TetraAs+5-FU and TetraAs+paclitaxel showed synergistic and additive interaction, respectively. On the other hand, TetraAs with cisplatin group appeared to be strongly antagonistic. Apoptotic population was measured and compared between single and combination treatment. The apoptotic cells for the combination of TetraAs+5-FU showed significant increase compared to single TetraAs treatment. On the contrary, TetraAs+cisplatin showed less apoptotic cells compared to TetraAs or cisplatin alone treatment. Overall, our results indicate that TetraAs can be effectively combined with 5-FU or paclitaxel, but not with cisplatin for synergistic anti-cancer effect, which warrants further evaluation using in vivo models.

• 한국항공우주학회지
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• 제30권6호
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• pp.1-6
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• 2002

마이크로 연소실을 장착한 MAV 추진 장치용 단기통 MEMS 엔진을 제작하였다. 본연구에서는 MEMS 크기의 왕복운동 내연기관의 타당성을 검증하고 실용화를 위한 설계 및 가공데이터를 축적하고자 하였다. 엔진 블록은 가공의 정밀도와 내열성등을 고려하여 감광유리 웨이퍼를 사용하였으며, 점화 전극은 베이스 플레이트 위에 니켈 도금으로 제작하였다. 감광유리판은 등방성 에칭의 특성이 탁월하여 마이크로 엔진의 실린더와 피스톤과 같이 비교적 깊은 식각이 가능함을 확인하였다. 전체 엔진은 세 개의 별도 가공된 레이어를 접착하여 조립한다. 본연구의 엔진 연소실은 깊이는 1mn, 폭 2mn이며, 피스턴은 수소-공기 예 혼합 가스의 연소압력에 의하여 구동된다. 가공된 엔진의 연소실험을 통하여, 점화, 화염전파 및 피스턴 구동을 확인하였으며, 실용화를 위한 연구가 요구되고 있다.

• 한국수정란이식학회지
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• 제25권4호
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• pp.237-245
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• 2010

Only an optimum number of viable spermatozoa in a frozen-thawed insemination dose can ensure conception at artificial insemination (AI). We report here the percentages of normal, abnormal and viable spermatozoa present in the frozen-thawed semen of 20 Black Bengal bucks used for commercial AI. Bucks in this experiment were of 19.3~46.1 months old and 25~42 kg body weight. Four semen straws (0.25 ml) from each buck were collected for evaluation of their kinetic parameters. Scrotal circumference was measured by using a scrotal tape, sperm motility was estimated on eye estimation and sperm concentration was determined by using a haemocytometer. Sperm morphology was studied in paraformaldehyde fixed spermatozoa under differential interference contrast (DIC) microscope. To determine the proportion of live (plasma membrane intact) spermatozoa, semen was stained with SYBR-14 and propidium iodide and examined under fluorescent microscope. Scrotal circumference, post-thaw sperm motility, sperm concentration per insemination dose and proportion of normal spermatozoa were $21.5{\pm}0.7\;cm$, $43.5 {\pm}5.4%$, $83.5{\pm}6.7$ million and $88.3{\pm}4.1%$, respectively. The percentages of spermatozoa with head shape and acrosome abnormalities were lower ($2.7{\pm}1.1$ and $1.4{\pm}1.3$, respectively), whereas higher percentages of abnormalities ($7.0{\pm}1.8$) were observed in mid piece and tail portion. The proportion of live spermatozoa was $28.5{\pm}5.4$. It is concluded that although a good number of morphologically normal spermatozoa are present in the insemination dose, the proportion of live spermatozoa is low, which warrants further improvements of buck semen freezing procedures to ensure good quality at AI.

• Archives of Pharmacal Research
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• 제27권5호
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• pp.576-580
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• 2004

Primaquine is used for relapses caused by vivax malaria hypnozoites. No studies on the pharmacokinetics of primaquine (PMQ) has been reported in Korean patients. In our study, thirty vivax malaria patients were given 15 mg primaquine daily for 14 days after 3 days of chloroquine treatment. Plasma samples were taken at intervals after each daily dose of PMQ for 3 days. Plasma concentrations of PMQ and carboxyprimaquine (CPMQ), the major metabolite of primaquine, were measured by HPLC. The PMQ concentrations reached a maximum of 0.28$\pm$0.18 $\mu\textrm{g}$/mL at 1.5 h after the first dose. The maximum concentration of CPMQ was 0.32$\pm$0.13 $\mu\textrm{g}$/mL at 4 h. Higher drug concentrations with repeated dosing were observed for CPMQ, but not for the parent drug, PMQ. The elimination half-life was 3.76$\pm$1.8 hand 15.7$\pm$12.2 h, for PMQ and CPMQ, respectively. Large variation in the plasma concentrations of both drugs was observed. Overall, PMQ is absorbed and metabolized rapidly after oral administration. It was noted that the mean peak plasma concentration of PMQ was significantly higher and that of CPMQ was lower in our patients compared to other studies. This suggests a potential difference of inter-ethnic groups, which warrants further investigations.