• Korean System Dynamics Review
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• v.10 no.1
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• pp.5-32
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• 2009

This paper revisited the key advances on System Dynamics modeling about traditional macro-economic models and economic growth structures, and then tries to elaborate a new model based on the endogenous growth theory that incorporates new growth factors, relevant to knowledge/technology as well as the Environment, into traditional growth models. Accordingly, the new model augments the acceleration and multiplier loops and the balancing ones representing market clearing mechanism with a simple numerical example. The authors thus provides macroeconomic System Dynamics analysts with a milestone to model macro-economic structures reflecting on traditional and cutting-edge theories on sustainable economic growth and general equilibrium modeling.

• Korean Journal of Microbiology
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• v.3 no.2
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• pp.15-21
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• 1965

Using the synchronous culture method and the manometric technique, changes in respiratory activities, utilization of some organic acids (succinate, malate, lactate and acetate etc.) and its effect on glucose metabolism in Chlorella cells at different growing stages were measured. 1) Endogenous respiration of the cells was not active at growing stage and was almost constant throughout the early ripening, maturing and division stages. 2) Lactate was utilized as respiratory substrate better than other organic acids tested. Exogenous respiration of glucose was most active at growing and maturing stages and was decreased strikingly at division stage. 3) Succinate and citrate inhibited endogenous and glucose respiration of the cells throughout the all life cycle. 4) Malate and acetate were utilized in the cells at early growing and division stages better, and malate enhanced the glucose respiration while in case of acetate it was depressed. 5) Calcium ion inhibited not only permeability of respiratory substrate but endogenous respiration itself.

• Journal of Pharmaceutical Investigation
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• v.23 no.1
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• pp.1-9
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• 1993

The endothelial cell of brain capillary called the blood-brain barrier (BBB) has carrier-mediated transport systems for nutrients and drugs. The mechanism of the BBB transport of basic and acidic drugs has been reviewed and examined for endogenous transport systems in BBB in WKY and SHRSP. Acidic drugs such as salicylic acid and basic drugs such as eperisone are taken up in a carrier mediated manner through the BBB via the monocarboxylic acid and amine transport systems. The specific dysfunction for the choline transport at the BBB in SHRSP would affect the function of the brain endothelial cell and brain parenchymal cell. The utilization of the endogenous transport systems of monocarboxylic acid and amine could be promising strategy for the effective drug delivery to the brain.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.11
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• pp.1634-1641
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• 2005

Generally, dietary fibre (DF) includes lignin, non-starch polysaccharides (NSP) and resistant starch (RS). In monogastric species, low levels of dietary fibre in the diet are associated with various diseases and high levels reduce nutrient digestibilities. In this study, the effects of different types and levels of NSP (soluble: $\beta$-glucan, insoluble cellulose) and resistant starch on mucin secretion and endogenous nitrogen and amino acid losses in pigs were investigated. A total of 25 five-week-old weaner pigs (9.5 kg${\pm}$1.5 kg), were randomly allocated to each of five experimental diets. Different levels of purified barley $\beta$-glucan (BG) extract (5 or 10% of $Glucagel^{(R)}$ $\beta$-glucan, providing 4 or 8% of BG in the diet), and resistant starch (RS) (8.3 or 16.6% of Hi-$Maize^{TM}$, providing 5 or 10% RS in the diet) were substituted for wheat starch in a purified diet in which enzymatically-hydrolysed casein was the sole source of protein. The diets were fed for 21 days. No statistically significant difference between treatments (p>0.05) was observed for growth performance and organs weights. No difference in ileal starch digestibility was observed between pigs on the cellulose or $\beta$-glucan diets. However, as the level of resistant starch in the diet increased the ileal starch digestibility decreased (p<0.05). The inclusion of resistant starch in the diet (5 or 10%) did not increase mucin production when compared with the cellulose-only diet. However, as the level of beta-glucan in the diet increased, both crude mucin in the digesta dry matter and per kg dry matter intake increased (p<0.05). Pigs fed the diet containing 8% of beta-glucan had higher endogenous loss flow than those fed the diets including 5 or 10% of resistant starch or 4% of $\beta$-glucan. In conclusion, dietary inclusion of resistant starch increased the level of starch reaching the large intestine without any effect on mucin secretion, or endogenous nitrogen or amino acid losses content in the small intestine. The addition of $\beta$-glucan to a diet containing cellulose increases both mucin secretion and endogenous amino acid and nitrogen losses in the small intestine.

• Journal of Life Science
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• v.24 no.10
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• pp.1137-1143
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• 2014

Doxorubicin is a general chemotherapy drug widely used for a number of cancers. However, the correlation between endogenous nitric oxide ($NO^{\bullet}$) levels and chemoresistance to doxorubicin remains unclear. In this study, we investigated the effect of endogenous $NO^{\bullet}$ on the anticancer activity of doxorubicin in human colon cancer cell lines HCT116 and HT29 with different p53 status. The cells were treated with either doxorubicin alone or in combination with the $NO^{\bullet}$ synthase (NOS) inhibitor $N^G$-monomethyl-L-arginine (NMA). Doxorubicin differentially inhibited the growth of both the HCT116 (p53-WT) and HT29 (p53-MUT) cells, which was mitigated by cotreatment with NMA. Further studies revealed that inhibition of endogenous $NO^{\bullet}$ mitigated doxorubicin-induced apoptosis in the HCT116 and HT29 cells, as evidenced by apoptotic DNA fragmentation and the sub-G1 peak of apoptotic markers. Apoptosis was delayed in the HT29 cells, and its magnitude was greatly reduced, underscoring the importance of the modulation of p53 in the response. RT-PCR analysis revealed that doxorubicin down-regulated levels of inhibitors of the apoptosis family (cellular IAP-1 and-2). Collectively, these data show that induction of apoptosis by doxorubicin in human colon cancer cells is possibly related to modulation of endogenous $NO^{\bullet}$, the expression of the IAP family of genes, and the status of p53. The underlying mechanisms may represent potential targets for adjuvant strategies to improve the efficacy of chemotherapy for colon cancer.

• Analytical Science and Technology
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• v.24 no.2
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• pp.142-149
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• 2011

This study was conducted to define metabolite of the resveratrol by gas chromatography- time-offlight mass spectrometric detection. From these results, we suppose that the structure of metabolite is the result of reduction of double-bond attached by two-phenyl groups. Also, validity of method for determining metabolite of resveratrol and endogenous steroids was tested. The recoveries ranged from 96.47 to 114.74%, and intraand inter-day precision ranged 11.40 - 10.87% and 1.10 - 10.93%, accuracy ranged 80.03 - 119.92% and 80.02 - 119.56%, respectively. Resveratrol and endogenous steroids had correlation coefficients above or equal to 0.996. The method was successfully validated for the determination of resveratrol and endogenous steroids. Urinary samples from volunteers dosed resveratrol were analyzed to confirm a correlation resveratrol and its metabolite. From these results, the highest level of resveratrol and its metabolite was excreted in 10 - 15 hr more slowly than common drug, and conversion rate of metabolite was higher in woman than that in man. In addition, endogenous steroids were shown same the highest level of 10 - 15 hr. For estrone and estradiol, sensitivity was relatively higher in female than in man. And there were no significant changes of excretion patterns in the other endogenous steroids. Thus, we assumed that activation of resveratrol has impact on woman than man.

• Journal of Nutrition and Health
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• v.25 no.6
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• pp.492-500
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• 1992

The rate of vitamin K-dependent carboxylation of endogenous liver microsomal proteins and an exogenous peptide substrate for carboxylase were measured to test the effects of excess vitamin A on vitamin K function in rats. In vitro vitamin A incubation in normal rat microsomes of vitamin K-sufficient ras did not influence the carboxylation rates of either endogenous prothrombin precursors or a peptide substrate added, Similarly vitamin A incubation in micro-somes from control and excess vitamin A-fed rats that were on vitamin K-free diet did not change the rate significantly within the respectively groups ; however the rates of endogenous protein carboxylation from excess vitamin A-fed rats tended to be increased by the in vitro vitamin A addition compared to that of control rats. Excess vitamin A-fed rats had 2- to 3- fold higher carboxylase activites of endogenous protein carboxylation either with or without the invitro vitamin A incubation than did control rats. In an in vivo study carboxyalase activites with an added exogenous peptide substrate were not influenced by excess intake of vitamin excess vitamin A-fed rats than for control rats. Carboxylase activites tended to be increased amounts of vitamin A on endogenous protein carboxylation appeareed as early as one week post-initiation of the diet. The results of this study indicate that excess vitamin A produces toxic effect rapidly and that excess dietary vitamin A increase the rate of carboxylation of endogenous protein mainly prothrombin precursors which is an indication of vitamin K defi-ciency.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.8
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• pp.1209-1223
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• 2009

In this review, the terminology that is used to describe ileal amino acid (AA) digestibilities in piglet feed ingredients is defined. If one accepts that the determination of AA digestibilities should be based on the ileal analysis method, one should consider that ileal digesta contains variable amounts of endogenous crude protein (CP), which originates mainly from digestive secretions, sloughedoff epithelial cells and mucins. The ileal endogenous CP and AA losses are separated into basal ileal endogenous CP and AA losses ($IAAL_{B}$), which are not influenced by the feed ingredient composition, and specific ileal endogenous CP and AA losses ($IAAL_{S}$), which are induced by feed ingredient characteristics such as level and type of fiber and anti-nutritional factors (ANF). Depending how ileal endogenous CP and AA losses are considered in the measurement of CP and AA digestibilities, digestibility values are expressed as apparent (AID), standardized (SID), or true (TID) ileal digestibilities of CP and AA. The main concern associated with the use of AID values in diet formulation for pigs is that they are not additive in mixtures of feed ingredients. Consequently, the concept of standardized ileal CP and AA digestibilities was introduced by correcting AID values for basal ileal endogenous CP and AA losses ($IAAL_{B}$). The correction for both $IAAL_{B}$ and $IAAL_{S}$ yields TID values, however, routine procedures to measure $IAAL_{S}$ are not yet available. In principle, SID values should be preferred, because they represent the fundamental properties of the feed ingredient. There exist only few reports on SID of CP and AA in feedstuffs frequently used in piglet nutrition. These include soybeans (SB), soybean meal (SBM), soy proteins (SP), soy protein concentrate (SPC), soy protein isolate (SPI), corn gluten (CG), wheat gluten (WG), pea protein (PeaP), potato protein (PotP), fish meal (FM) and whey proteins (WP), but the results obtained are inconsistent. Differences in SID values within feed ingredients may, at least in part, be attributed to different processing conditions or inherent differences of the assay feed ingredients. Moreover, there is some evidence that the determination of SID values and $IAAL_{B}$ in piglets may be confounded by the dietary CP level of the assay diet, age and (or) body weight (BW), the level of feed intake or the methodological approach used to determine $IAAL_{B}$.

• Clinical and Experimental Reproductive Medicine
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• v.26 no.3
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• pp.389-398
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• 1999

Objective: This study was designed to evaluate the effects of endogenous LH surge, GnRH agonist (GnRH-a) or human chorionic gonadotropin (hCG) as ovulation trigger on pregnancy rate by intrauterine insemination (IUI). Method: Patients received daily 100 mg of clomiphene citrate (CC) for 5 days starting on the third day of the menstrual cycle followed by human menopausal gonadotropin (hMG) for ovulation induction. Follicles larger than >16 mm in diameter were present in the ovary, frequent LH tests in urine were introduced to detect an endogenous LH surge. Final follicular maturation and ovulation were induced by GnRH-a 0.1 mg (s.c.) or hCG $5,000{\sim}10,000$ IU (i.m.) administration except natural ovulation. Pregnancy was classified as clinical if a gestational sac or fetal cardiac activity was seen on ultrasound. Results: There were no differences in age, duration of infertility and follicle size, but more ampules of hMG were used in GnRH-a group compared to hCG 10,000 IU treated group (p<0.05). Lower level of estradiol ($E_2$) on the day of hCG or GnRH-a injection was observed in hCG 10,000 IU group than other treatment groups (p<0.01). The overall clinical pregnancy rate was 19.8% per cycle (32/162) and 22.2% per patient (32/144). Pregnancy rate was higher in natural-endogenous LH surge group (37.5%, 9/24) than GnRH-a (18.8%) or hCG treated group (20.9% & 13.9%), but this difference was not statistically significant. No patient developed ovarian hyperstimulation. Abortion rate was 22.2% (2/9) in hCG 5,000 IU group. Delivery or ongoing pregnancy rate was 37.5% (9/24), 18.8% (3/16), 16.3% (7/43) and 13.9% (11/79) in endogenous LH surge, GnRH-a, hCG 5,000 IU and hCG 10,000 IU treatment groups, respectively. Conclusion: These results support the concept that use of natural-endogenous LH surge in stimulated cycles may be more effective to obtain pregnancies by IUI than GnRH-a or hCG administration.

• Journal of Nutrition and Health
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• v.9 no.3
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• pp.8-17
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• 1976

This study was carried out to estimate the minimum protein requirement for the Korean college girls, and to see the effect of carbohydrate intake on the minimum protein requirement in the rat. In the first experiment, three students attending Ewha Womans University were given protein free diet for 7 days while caloric intake were adjusted to maintain constant body weight. Endogenous nitrogen excretion was measured to estimate their minimum protein requirement. Second experiment was carried out in 3 parts to find out the effect of carbohydrate intake on the minimum protein requirement using 15 female, 50 days old rats weighing 120g. Inexperiment 2-1, the rats were fed protein free diet for 9 days and endogenous nitrogen excretion was measured to determine the minimum protein requirement of the rats. In experiment 2-2, the minimum casein requirement of the rats needed to maintain nitrogen equilibrium was estimated by the least squares regression method feeding 3 different levels of casein determined from the result of experiment 2-1. Finally, in experiment 2-3, the rats were given the minimum casein requirement for 7 days with 3 different levels of carbohydrate to find out the effect of carbohydrate intake on the nitrogen balance. The results of this study were as follows. Experiment I. Daily endogenous nitrogen losses of 3 college girls were 1.89g in urine, 1.10g in feces and 0.0108g from skin since the total daily endogenous nitrogen loss was 3.0g and the total daily nitrogen intake was 0.52g, the minimum nitrogen requirement of these subjects was about 2.48g/day (15.5g protein/day). Experiment II. Experiment 2-1: daily endogenous nitrogen losses of the rats fed protein free diet were $22.63{\pm}0.48\;mg$ through urine and $13.12{\pm}0.47\;mg$ in feces. The total daily endogenous nitrogen ouput was $35.71{\pm}1.27\;mg$ and the minimum protein requirement of the rats was 225mg/day in this study. Experiment 2-2: the minimum casein requirement needed to maintain the rats in nitrogen equilibrium was determined to be 340mg/day. Experiment 2-3: the rats were given 350mg/day casein with 3 different levels of carbohydrate (12,26 or 46 Cal by sugar-cornstarch mixture). The nitrogen balances were measured to be +0.0021, +0.0073 and +0.0143 respectively and there were significant differences among 3 groups.