• Communications of Mathematical Education
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• v.22 no.4
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• pp.417-444
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• 2008

Many research papers on the college students' functional concept show they have poor understanding on this topic. To compare the results with that of Korean students, four interrelated topics are chosen: How do they understand the concept of function?; what are their misconceptions including epistemological obstacles?; How do the function concepts develop and are acquired? For this a survey has been conducted to 95 engineering students just before they start Calculus course. We have done research on other major areas including psychology, economics and statistics to see how function is defined in these areas. Function definitions from US math text books are also introduced. Based on the these and the survey, some suggestions are made on the new curriculum which treat function as a correspondence relation. Vertical line test should be added to the Algebra II/Pre calculus course to check the univalent property.

• Proceedings of the Ginseng society Conference
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• 2008.05a
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• pp.82-82
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• 2008

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.11
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• pp.1648-1657
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• 2014

In this study, the hepatic lipid-lowering effects and related mechanism of action of sujeonggwa were examined in hypercholesterolemia-induced apoprotein E knockout (apo E ko) mice. Sujeonggwa drink was prepared with cinnamon, ginger, and sugar by modifying the traditional recipe of sujeonggwa. Sugar was partially substituted with either stevia or short chain fructooligosaccharide (scFOS) in order to reduce the calorie content of sujeonggwa, which was measured by descriptive analysis. Apo E ko mice (n=42) were induced to have hypercholesterolemia (plasma total cholesterol concentration >1,000 mg/dL) by administration of a high cholesterol diet for 4 weeks, followed by division into six groups. Experimental groups were orally administered water as a vehicle (normal group), sugar solution (control group), commercially available 'V' sujeonggwa drink (positive control group), or three different types of sujeonggwa drinks (S-sugar, S-stevia, and S-scFOS group) for 6 weeks while high cholesterol diet was provided to all animals. Compared to the control group, concentrations of hepatic triglycerides, total cholesterol, thiobarbituric acid reactive substances, and reactive oxygen species in S-sugar, S-stevia, S-scFOS were significantly reduced (P<0.05), indicating that sujeonggwa had inhibitory effects on hepatic lipid accumulation. Protein expression levels of fatty acid synthase (FAS) and its transcription factor, sterol regulatory element-binding protein (SREBP)-1 responsible for triglyceride synthesis, as well as 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) and its transcription factor, SREBP-2 responsible for cholesterol synthesis, were also reduced in S-sugar, S-stevia, and S-scFOS groups (P<0.05). These benefits of sujeonggwa were even greater in S-stevia and S-scFOS compared to S-sugar. The beneficial effects of S-stevia on regulation of hepatic lipid metabolism were slightly greater than those of S-scFOS although the differences were not significant. In conclusion, sujeonggwa drinks, especially functional sujeonggwa drinks in which sugar was partially substituted with stevia or scFOS, inhibited hepatic lipid accumulation via suppressing FAS and HMGCR protein expression through down-regulation of SREBP-1 and 2.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.8
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• pp.1080-1088
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• 2013

Our previous results showed that kisspeptin-10 (Kp-10) injections via intraperitoneal (i.p.) once daily for three weeks notably promoted the egg laying rate in quails. In order to investigate the mechanism behind the effects of Kp-10 on enhancing the egg laying rate in birds, this study focused on the alternations of lipids synthesis in liver after Kp-10 injections. 75 female quails (22 d of age) were allocated to three groups randomly, and subjected to 0 (control, Con), 10 nmol (low dosage, L) and 100 nmol (high dosage, H) Kp-10 injections via i.p. once daily for three weeks, respectively. At d 52, quails were sacrificed and sampled for further analyses. Serum $E_2$ concentration was increased by Kp-10 injections, and reached statistical significance in H group. Serum triglyceride (TG) concentrations were increased by 46.7% in L group and 36.8% in H group, respectively, but did not reach statistical significance, and TG contents in liver were significantly elevated by Kp-10 injections in a dose-dependent manner. Serum total cholesterol (Tch) concentrations significantly decreased in H group, while in H group the hepatic Tch content was markedly increased. The level of non-esterified fatty acid (NEFA), apolipoprotein A1 and B (apoA1 and apoB) were not altered by Kp-10 injections. The genes expression of sterol regulatory element binding protein-1 (SREBP-1), fatty acid synthetase (FAS), apolipoprotein VLDL-II (apoVLDL-II), cholesterol $7{\alpha}$-hydroxylase (CYP7A1) and vitellogenin II (VTG-II) were significantly up-regulated by high but not low dosage of Kp-10 injection compared to the control group. However, the expression of SREBP-2, acetyl-CoA carboxylase ($ACC_{\alpha}$), malic enzyme (ME), stearoyl-CoA (${\Delta}9$) desaturase 1 (SCD1), apolipoprotein A1 (apoA1), fatty acid binding protein 2 (FABP2), 3-hydroxyl-3-methyl glutaryl-coenzyme A reductases (HMGCR), estrogen receptor ${\alpha}$, ${\beta}$($ER{\alpha}$ and ${\beta}$) mRNA were not affected by Kp-10 treatment. In line with hepatic mRNA abundance, hepatic SREBP1 protein content was significantly higher in H group. Although the mRNA expression was not altered, the content of $ER{\alpha}$ protein in liver was also significantly increased in H group. However, SREBP-2 protein content in liver was not changed by Kp-10 treatment. In conclusion, exogenous Kp-10 consecutive injections during juvenile stage significantly advanced the tempo of egg laying in quails, which was associated with the significant elevation in hepatic lipids synthesis and transport.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.1
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• pp.19-24
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• 2008

The purpose of this study was to detect expression of genes related to egg production in Taiwan Country chickens by suppression subtractive hybridization. Liver samples of mRNA extraction from two Taiwan Country chicken strains (L2 and B), originated from the same population but with very distinct egg production rates after long-term selection for egg and meat production respectively. Two-way subtraction was performed. The hepatic cDNA from the low egg production chickens (B) was subtracted from the hepatic cDNA from the high egg production strain (L2). The reversed subtraction (L2 from B) was also performed. The resulting differentially expressed gene fragments were cloned and sequenced. We sequenced 288 clones from the forward subtraction and 96 clones from the reverse subtraction. These genes were subjected to further screening to confirm the differential expression between the two genetic breeds of chickens. The apolipoprotein B (apoB) was expressed to a greater extent in the liver of the L2 than in the B line chickens. The 5-aminoimidazole- 4-carboxamide ribonucleotide formyltransferase/IMP cyclohydrolase (PURH) was expressed to a greater extent in the liver of the B than in the L2 strain chickens. We demonstrated that both apoB and PURH were more highly expressed in the liver than that in other tissues (muscle, ovary, and oviduct) in laying Taiwan Country chickens. Taken together, these data suggest that after the selection for egg production, expression of apoB and PURH genes were also changed. Whether the changed expression of these genes is directly related to egg production is not known, but these two genes may be useful markers for egg laying performance in Taiwan Country chickens.

• Korean Journal of Clinical Laboratory Science
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• v.36 no.2
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• pp.110-114
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• 2004

Apolipoprotein E is the major lipid-carrier protein in the brain, and several studies provided evidence that apolipoprotein E(ApoE) epsilon4 allele can be considered a genetic risk factor for Alzheimer's disease(AD). Inheritance of the APOE gene has three alleles: ${\varepsilon}2$, ${\varepsilon}3$ and ${\varepsilon}4$. There are six possible genotypes: ${\varepsilon}2/{\varepsilon}2$, ${\varepsilon}3/{\varepsilon}3$, ${\varepsilon}4/{\varepsilon}4$, ${\varepsilon}2/{\varepsilon}3$, ${\varepsilon}2/{\varepsilon}4$, ${\varepsilon}3/{\varepsilon}4$. AD is characterized by a progressive loss of function and death of nerve cells in several areas of the brain. The ${\varepsilon}4$ allele is associated with a risk for developing AD. People with the ${\varepsilon}4/{\varepsilon}4$ genotype have the highest risk, but people with the ${\varepsilon}2/{\varepsilon}4$ or ${\varepsilon}3/{\varepsilon}4$ genotypes are also likely to develop the disease. 64.3% of people carry the is ${\varepsilon}3/{\varepsilon}3$ genotype, 22.1% carry the second ${\varepsilon}3/{\varepsilon}4$ genotype but, ${\varepsilon}2/{\varepsilon}2$ genotype is not usually found of people carry the 3.6% is ${\varepsilon}4/{\varepsilon}4$ genotype in a total of a test group of 140 people. The ratio of ${\varepsilon}4/{\varepsilon}4$ genotype related directly with AD is less than the ${\varepsilon}3/{\varepsilon}3$ genotype, but the ${\varepsilon}2/{\varepsilon}4$ and ${\varepsilon}3/{\varepsilon}4$ genotype ratio of indirect AD risk is 25.7% in the group of people, regardless. Thus, we have referred to the benefit from the treatment of AD through apoE genotype diagnosis.

• International Journal of Oral Biology
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• v.37 no.3
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• pp.130-136
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• 2012

The GroEL heat-shock protein from Fusobacterium nucleatum, a periodontopathogen, activates risk factors for atherosclerosis in human microvascular endothelial cells (HMEC-1) and ApoE-/- mice. In this study, we analyzed the signaling pathways by which F. nucleatum GroEL induces the proinflammatory factors in HMEC-1 cells known to be risk factors associated with the development of atherosclerosis and identified the cellular receptor used by GroEL. The MAPK and NF-${\kappa}B$ signaling pathways were found to be activated by GroEL to induce the expression of interleukin-8 (IL-8), monocyte chemoattractant protein 1 (MCP-1), intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), E-selectin, and tissue factor (TF). These effects were inhibited by a TLR4 knockdown. Our results thus indicate that TLR4 is a key receptor that mediates the interaction of F. nucleatum GroEL with HMEC-1 cells and subsequently induces an inflammatory response via the MAPK and NF-${\kappa}B$ pathways.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.4 no.1
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• pp.26-31
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• 2018

Macrophages play a key role in atherosclerotic plaque formation, but their participation has been discerned largely via ex vivo analyses of atherosclerotic lesions. Therefore, we aimed to identify atherosclerosis on noninvasive in vivo imaging using reporter gene system. This study demonstrated that recruitment of macrophages could be detected in atherosclerotic plaques of Apolipoprotein E knockout (ApoE-/-) mice with a sodium iodide symporter (NIS) gene imaging system using $^{99m}Tc-SPECT$. This novel approach to tracking macrophages to atherosclerotic plaques in vivo could have applications in studies of arteriosclerotic vascular disease.

• Preventive Nutrition and Food Science
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• v.15 no.2
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• pp.83-87
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• 2010

The cholesterol-lowering effects of soymilk fermented with Bacillus subtilis KCCM42923 were studied in apolipoprotein E knockout (ApoE KO) mice and compared to the cholesterol-lowering effects of soymilk to which cheonggukjang powder had been added. ApoE KO mice were divided into 3 groups (n=7/group). Animals were fed either an atherogenic diet only (AD, control group), an AD supplemented with fermented soymilk containing Corni fructus (FSM group), or an AD supplemented with soymik to which cheonggukjang (CGJ) powder had been added at 5% (w/v) (CPS group) for 8 weeks. The amount of FSM or CPS supplementing the AD was 20.8 mL/kg BW. There were no differences in either body weight gain or organ weights among three groups. In the FSM group, the concentration of plasma total cholesterol (TC) and LDL cholesterol (LDLC) were significantly decreased by 26.2% and 30.3% compared with the values of the control group (p<0.05). However, the triglyceride (TG) and HDL-cholesterol (HDLC) levels were not affected. These beneficial effects of FSM on suppressing the increase in plasma cholesterol level by AD were greater than those of CPS, which revealed 15.4% and 16.4% inhibition for TC and LDLC, respectively. However, these differences between FSM and CPS groups were not significantly different. A preventative effect of FSM or CPS on the accumulation of hepatic TC, but not on TG, was observed. FSM and CPS did not demonstrate any effects on fecal lipid excretion. In conclusion, the cholesterol-lowering effects of the soymilk fermented with Bacillus subtilis KCCM42923 were comparable to CGJ powder-added soymilk. These results suggest that drinking FSM might provide beneficial effects on controlling plasma cholesterol levels.

• Safety and Health at Work
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• v.11 no.2
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• pp.178-186
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• 2020

Background: Cognitive impairment is a public health burden. Our objective was to investigate associations between work hours and cognitive function. Methods: Multi-Ethnic Study of Atherosclerosis (MESA) participants (n = 2,497; 50.7% men; age range 44-84 years) reported hours per week worked in all jobs in Exams 1 (2000-2002), 2 (2002-2004), 3 (2004-2005), and 5 (2010-2011). Cognitive function was assessed (Exam 5) using the Cognitive Abilities Screening Instrument (version 2), a measure of global cognitive functioning; the Digit Symbol Coding, a measure of processing speed; and the Digit Span test, a measure of attention and working memory. We used a prospective approach and linear regression to assess associations for every 10 hours of work. Results: Among all participants, associations of hours worked with cognitive function of any type were not statistically significant. In occupation-stratified analyses (interaction p = 0.051), longer work hours were associated with poorer global cognitive function among Sales/Office and blue-collar workers, after adjustment for age, sex, physical activity, body mass index, race/ethnicity, educational level, annual income, history of heart attack, diabetes, apolipoprotein E-epsilon 4 allele (ApoE4) status, birth-place, number of years in the United States, language spoken at MESA Exam 1, and work hours at Exam 5 (β = -0.55, 95% CI = -0.99, -0.09) and (β = -0.80, -1.51, -0.09), respectively. In occupation-stratified analyses (interaction p = 0.040), we also observed an inverse association with processing speed among blue-collar workers (adjusted β = -0.80, -1.52, -0.07). Sex, race/ethnicity, and ApoE4 did not significantly modify associations between work hours and cognitive function. Conclusion: Weak inverse associations were observed between work hours and cognitive function among Sales/Office and blue-collar workers.