• Biomolecules & Therapeutics
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• v.14 no.2
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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.

• Journal of the Korean School Mathematics Society
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• v.16 no.1
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• pp.241-263
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• 2013

The purpose of this paper is to investigate high school students' reasoning characteristics in problem solving. To do this, we selected five high school students as participants and presented them some open problems which allow diverse solving approaches, and recorded their problem solving process. Through analyzing their problem solving process relate to their solution, we found the followings: First, students quickly try to calculate without understanding the given problem. Second, students concern whether their solution is right or not rather than consider mathematical warrants for the results of their strategies. Third, students have difficulties to consider more than two conditions at the same time necessary to solve problem. Forth, students are not familiar to use precedence knowledge relate to given tasks. Fifth, students could have difficulties in problem solving because of easy generalization.

• Archives of Reconstructive Microsurgery
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• v.3 no.1
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• pp.64-71
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• 1994

The successful treatment of the extensively traumatized foot warrants reconstruction utilizing tissue that will provide adequate coverage, is resistant to infection, thin enough to conform to the contours of the foot as well as durable to constant frictional movement and weight bearing. Currently, free flaps offer the best means in achieving these difficult and sometimes contradictory goals. We treated twenty-one patients suffering from extensive soft tissue loss of the foot due to trauma, electric burn or postburn sequelae with free flaps. A fasciocutaneous, musculocutaneous or muscle flap with skin grafting was used based on the location, volume of tissue required, and the functional anatomical requirement of the injured region. The follow-up duration averaged twenty-nine months. From our group of patients, we believe that the muscle free flap with skin grafting offers the most favorable outcome.

• Journal of Educational Research in Mathematics
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• v.24 no.1
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• pp.1-27
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• 2014

In the present study, we analyze the four participating 9th grade students' mathematical reasoning processes in their dragging activities while solving open-ended geometry problems in terms of abduction, induction and deduction. The results of the analysis are as follows. First, the students utilized 'abduction' to adopt their hypotheses, 'induction' to generalize them by examining various cases and 'deduction' to provide warrants for the hypotheses. Secondly, in the abduction process, 'wandering dragging' and 'guided dragging' seemed to help the students formulate their hypotheses, and in the induction process, 'dragging test' was mainly used to confirm the hypotheses. Despite of the emerging mathematical reasoning via their dragging activities, several difficulties were identified in their solving processes such as misunderstanding shapes as fixed figures, not easily recognizing the concept of dependency or path, not smoothly proceeding from probabilistic reasoning to deduction, and trapping into circular logic.

• Journal of Preventive Medicine and Public Health
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• v.53 no.3
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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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• v.6 no.2
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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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• v.37 no.5
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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.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.6
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• pp.1-6
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• 2002

Micro engine that includes Micro scale combustor is fabricated. Design target was focused on the observation of combustion driven actuation in MEMS scale. Combustor design parameters are somewhat less than the size recommended by feasibility test. The engine structure is fabricated by isotropic etching of the photosensitive glass wafers. Electrode is formed by electroplating of the Nickel. Photosensitive glass can be etched isotropically with almost vertical angle. Bonding and assembly of structured photosensitive glass wafer from the engine. Combustor size was determined to be 1mn scale. Piston in cylinder moves by fuel injection and reaction. In firing test, adequate engine operation including ignition, flame propagation and piston motion was observed. Present study warrants further application research on MEMS scale internal combustion power units.

• Journal of Embryo Transfer
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• v.25 no.4
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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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• v.27 no.5
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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.