• KDI Journal of Economic Policy
• /
• v.34 no.2
• /
• pp.1-15
• /
• 2012

We develop an identity choice model within the context of a stereotyping-cum-signaling framework. The model allows us to explore implications of the fact that, when individuals can choose identity, then the distribution of abilities within distinct identity groups becomes endogenous. This is significant because, when identity is exogenous and if the ability distributions within groups are the same, then inequality of group reputations in equilibrium can only arise if there is a positive feedback between group reputation and individual human capital investment activities (Arrow, 1973; Coate and Loury, 1993). Here we show that when group membership is endogenous then the logic of individuals' identity choices leads there to be a positive selection of higher ability individuals into the group with a better reputation. This happens because those for whom human-capital-investment is less costly are also those who stand to gain more from joining the favored group. As a result, ability distributions within distinct groups can endogenously diverge, reinforcing incentive-feedbacks. We develop the theoretical framework that can examine the positive selection and the endogenous group formation. The model implies that inequality deriving from stereotyping of endogenously constructed social groups is at least as great as the inequality that can emerge between exogenously given groups.

• Journal of the Economic Geographical Society of Korea
• /
• v.14 no.4
• /
• pp.453-466
• /
• 2011

The main aim of this paper is to explore the Korean development strategy in the context of trajectories of the economic development from 1961 to 2010. The fast and high growth in the period of 1961 and 2010 resulted from the 'export-oriented industrialization' through a combination of 'mass production-mass exports' and '(relatively) high productivity-low wages' up to the late 1980s, a mixture of 'mass production-mass exports' and '(relatively) high productivity-high wages' to the late 1990s, and a combination of the reformation of public and private sectors for overcoming the Korean financial crisis and the gradual improvement of the marketization and social safety net since 2000. With respect to this model of development, the global and national modes of regulation were established. Along with the formation of endogenous forces (as the national mode of regulation), that of exogenous forces (as the global mode of regulation) are the important rules of the game at the global level, which lead and stabilize the process of accumulation by the export-led industrialization in Korea. In this respect, the establishment of global modes of regulation is led by exogenous forces such as trade regulations, exchange rates, global-Korean industrial relations, and global regulations of loans to developing countries. On the other hand, the national modes of regulation are formed by endogenous forces such as the triangular relationship of the state, capital and labor.

• Journal of Pharmaceutical Investigation
• /
• v.31 no.1
• /
• pp.49-55
• /
• 2001

Acetyl-L-carnitine (ALC), an endogenous component of the L-carnitine family, is naturally occurring molecule synthesized from L-carnitine (LC) by carnitine acetyl transferase. ALC has been shown to improve the cognitive performance of patients suffering from dementia of the Alzheimer's type and proposed for treating Alzheimer's disease in pharmacological doses. The purpose of the present study was to evaluate the bioequivalence of two ALC tablets, $Nicetile^{TM}$ (Dong-A pharmaceutical Co., Ltd.) and $Neurocetil^{TM}$ (Kyung-Dong Pharmaceutical Co., Ltd.), according to the guidelines of Korea Food and Drug Administration. Twenty six normal male volunteers, $22.80{\pm}2.76$ year in age and $63.07{\pm}7.98\;kg$ in body weight, were divided into two groups and a randomized $2{\times}2$ cross-over study was employed. After one tablet containing 500 mg of ALC was orally administered, blood was taken at predetermined time intervals and the concentrations of ALC in serum were determined using HPLC with fluorescence detector. Because of the presence of endogenous ALC, the calibration was performed using dialyzed serum. Pharmacokinetic parameters such as $AUC_t$, $C_{max}\;and\;T_{max}$ were calculated and ANOVA was utilized for the statistical analysis of the parameters. The results showed that the differences in $AUC_t$, $C_{max}\;and\;T_{max}$ between two tablets were 2.72%, -0.65% and -8.42%, respectively, when calculated against the $Nicetile^{TM}$ tablet. The powers $(1-{\beta})$ for $AUC_t\;and\;C_{max}$ were 94.87% and 87.17%, respectively. Minimum detectable differences $({\Delta})$ at ${\alpha}=0.05$ and $1-{\beta}=0.8$ were less than 20% (e.g., 15.58% and 19.16% $AUC_t\;C_{max}$, respectively). The 90% confidence intervals were within ${\pm}20%$ (e.g., $-11.84{\sim}6.41$ and $-10.57{\sim}11.88$for $AUC_t\;and\;C_{max}$, respectively). Two parameters met the criteria of KFDA for bioequivalence, indicating that $Neurocetil^{TM}$ tablet is bioequivalent to $Nicetile^{TM}$ tablet.

• Journal of Embryo Transfer
• /
• v.30 no.3
• /
• pp.249-255
• /
• 2015

Diabetes mellitus, the most common metabolic disorder, is divided into two types: type 1 and type 2. The essential treatment of type 1 diabetes, caused by immune-mediated destruction of ${\beta}-cells$, is transplantation of the pancreas; however, this treatment is limited by issues such as the lack of donors for islet transplantation and immune rejection. As an alternative approach, stem cell therapy has been used as a new tool. The present study revealed that bone marrowderived mesenchymal stromal cells (BM-MSCs) could be transdifferentiated into pancreatic cells by the insertion of a key gene for embryonic development of the pancreas, the pancreatic and duodenal homeobox factor 1 (PDX1). To avoid immune rejection associated with xenotransplantation and to develop a new cell-based treatment, BM-MSCs from ${\alpha}$-1,3-galactosyltransferase knockout (GalT KO) pigs were used as the source of the cells. Transfection of the EGFP-hPDX1 gene into GalT KO pig-derived BM-MSCs was performed by electroporation. Cells were evaluated for hPDX1 expression by immunofluorescence and RT-PCR. Transdifferentiation into pancreatic cells was confirmed by morphological transformation, immunofluorescence, and endogenous pPDX1 gene expression. At 3~4 weeks after transduction, cell morphology changed from spindle-like shape to round shape, similar to that observed in cuboidal epithelium expressing EGFP. Results of RT-PCR confirmed the expression of both exogenous hPDX1 and endogenous pPDX1. Therefore, GalT KO pig-derived BM-MSCs transdifferentiated into pancreatic cells by transfection of hPDX1. The present results are indicative of the therapeutic potential of PDX1-expressing GalT KO pig-derived BM-MSCs in ${\beta}-cell$ replacement. This potential needs to be explored further by using in vivo studies to confirm these findings.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 2003.11a
• /
• pp.87-87
• /
• 2003

Taurine (2-aminoethanesulfonic acid, $^{+}NH_3CH_2CH_2{SO_3}^{-}$) is endogenous $\beta$-amino acid which is essential in fetal nutrition and development and is present in abundant quantities in several tissues of fetus. In utero, taurine deficiency causes abnormal development and abnormal function of brain, retina, kidney and myocardium. Thus, transfer of taurine into fetus is important during embryonic development. Taurine transporter (TauT) has 12 hydrophobic membrane -spanning domains, which is typical of the $Na^{+}$- and $Cl^{-}$-dependent transporter gene family. Among the various biosynthetic enzymes of taurine, cysteine sulfinic acid decarboxylase (CSD) is the rate-limiting enzyme for biosynthesis of taurine. However, the enzyme activities of taurine biosynthesis are limited in early stage of embryonic development. To analyze the expression period of TauT and CSD during embryonic development, we have investigated the gene expression of TauT and CSD using reverse transcriptase polymerase chain reaction (RT-PCR) in mouse and chicken embryos. RT-PCR anaylsis revealed that both TauT and CSD mRNAs were already expressed at Day-4.5 in mouse embryo. In chicken whole embryo, TauT and CSD mRNAs began to appear on developing times of 48 hrs and 12 hrs, respectively. TauT mRNA was detected in the organs of heart, brain and eye of the day-3 chicken embryo. Our data show that TauT and CSD mRNAs were expressed in early stage of embryonic development.

• Journal of Bio-Environment Control
• /
• v.25 no.4
• /
• pp.240-248
• /
• 2016

The objective of this study was to determine the effect of exogenous abscisic acid (ABA) on the red coloration and endogenous ABA contents of apple fruit skins. ABA and fluridone (an ABA synthetic inhibitor, FD) was sprayed on 'Hongro' apple fruit skins at 107 days after full bloom (DAFB). Visual coloration and hunter's color values were not affected by the ABA and FD treatments. Anthocyanin contents in fruit skins increased similarly to hunter $a^*$ values of fruit skins, but ABA and FD did not affect its accumulations. Liquid chromatography analysis revealed that endogenous ABA contents in control fruit increased at first and then decreased from 12 hours after the treatment. ABA treatment increased ABA contents in fruit skins from 2 hour after the treatment and it lasted until the end of the treatments. FD decreased ABA contents in fruit skins from 6 hours after the treatment. ABA treatment increased MdNCED2 (an ABA biosynthetic gene), MdACO1 (an ethylene biosynthetic gene), and MdCHS and MdDFR expressions. However, MdUFGT expressions were not affected by ABA treatment.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.22
• /
• pp.9557-9565
• /
• 2014

MiRNAs are endogenous, single stranded ~22-nucleotide non-coding RNAs (ncRNAs) which are transcribed by RNA polymerase II and mediate negative post-transcriptional gene regulation through binding to 3'untranslated regions (UTR), possibly open reading frames (ORFs) or 5'UTRs of target mRNAs. MiRNAs are involved in the normal physiology of eukaryotic cells, so dysregulation may be associated with diseases like cancer, and neurodegenerative, heart and other disorders. Among all cancers, lung cancer, with high incidence and mortality worldwide, is classified into two main groups: non-small cell lung cancer and small cell lung cancer. Recent promising studies suggest that gene expression profiles and miRNA signatures could be a useful step in a noninvasive, low-cost and repeatable screening process of lung cancer. Similarly, every stage of lung development during fetal life is associated with specific miRNAs. Since lung development and lung cancer phenomena share the same physiological, biological and molecular processes like cell proliferation, development and shared mRNA or expression regulation pathways, and according to data adopted from various studies, they may have partially shared miRNA signature. Thus, focusing on lung cancer in relation to lung development in miRNA studies might provide clues for lung cancer diagnosis and prognosis.

• Journal of the Korean Geographical Society
• /
• v.44 no.5
• /
• pp.634-646
• /
• 2009

This paper critically examines cluster dynamics and development in a multi-scalar approach, criticizing both the argument overemphasizing local networks and endogenous development for regional development and the contention highlighting global networks and the role of global players. We argue that state policies, exogenous and direct, play a significant part in cluster dynamics and development especially in the case of Korea where the state government's strong policies have led to rapid industrialization. We analyze multi-scalar factors, especially the government policies at a national level, in the development paths of the three cases including Ulsan automobile cluster, Daedeok research cluster, and Dongdaemun fashion cluster.

• BMB Reports
• /
• v.28 no.5
• /
• pp.414-419
• /
• 1995

The retroviruses carrying ${\nu}-myc$ and ${\nu}-raf$ oncogenes were infected into fetal thymic organ culture (FTOC) to study the molecular mechanisms involved in T cell development. T cell lymphomas in the different stages of T cell development were obtained from this culture system. Interestingly, a few cell lines obtained from this system have a lack of transfected oncogenes, however these cells have the characteristics of transformed cells. In spite of the discrete phenotype of these transformed cell lines, the same pattern of recombination of endogenous c-raf genes was detected from Southern blot analysis. We suggest in this regard that the translocation event of thymocytes, or abnormal promoter activity, can cause lymphomagenesis by way of c-raf.

• Proceedings of the Botanical Society of Korea Conference
• /
• 1987.07a
• /
• pp.241-260
• /
• 1987

The regulatory mechanisms of gene expression in higher plant were not ascertained in detail because the genome size is very large and complex. However, the above-mentioned study is remarkably progressed in parallel with development of DNA recombinant technology and plant vector system. Some research results connected with the mechanisms could be summarized as follows. 1. Many plant genes including chloroplast genes are cloned. 2. The structures of some regulatory regions of gene expression are determined, and it is confirmed that new regulatory units are made by transposable elements. 3. Plant gene expression is regulated not only at transcriptional level but also at translational level. 4. The factors that regulate plant gene expression could be divided as two categorys. One is endogenous elements including the structural change of chromatin during development stage and tissue differentiation. The other is environmental stimulations such as air, water, heat, salts and light. However, some sufficient research-aid fund is essential in order to study the regulatory mechanisms of gene expression more systematically.