• Molecules and Cells
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• v.46 no.7
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• pp.399-413
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• 2023

cAMP responsive element-binding protein (CREB) is one of the most intensively studied phosphorylation-dependent transcription factors that provide evolutionarily conserved mechanisms of differential gene expression in vertebrates and invertebrates. Many cellular protein kinases that function downstream of distinct cell surface receptors are responsible for the activation of CREB. Upon functional dimerization of the activated CREB to cis-acting cAMP responsive elements within the promoters of target genes, it facilitates signal-dependent gene expression. From the discovery of CREB, which is ubiquitously expressed, it has been proven to be involved in a variety of cellular processes that include cell proliferation, adaptation, survival, differentiation, and physiology, through the control of target gene expression. In this review, we highlight the essential roles of CREB proteins in the nervous system, the immune system, cancer development, hepatic physiology, and cardiovascular function and further discuss a wide range of CREB-associated diseases and molecular mechanisms underlying the pathogenesis of these diseases.

• Journal of Pharmaceutical Investigation
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• v.25 no.3
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• pp.1-6
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• 1995

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1988.10a
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• pp.16-16
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• 1988

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.633-635
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• 2007

To cope with increasing power demand in metropolitan area, the power system in Korea has equipped with unit generator of large capacity, high density and uneven distribution, and transmission line of long distance, large capacity and high voltage. As the power system growing up enormous, it has become difficult to maintain the standard voltage in case of radical fluctuation of load or severe change of voltage by power system fault for its weakness of responsive characteristics although the power condenser has been installed to solve the unstability by lack of reactive power. Consequently, we review harmonic wave production and control characteristics to solve unstability problem of voltage in northern metropolitan, to reduce transmission restriction cost and to minimize load shedding by relocation of SVC (Static Var Compensator), which is highly effective for improvement of responsive characteristics for radical voltage fluctuation.

• Korean Chemical Engineering Research
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• v.61 no.4
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• pp.570-575
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• 2023

Targeted anticancer drug delivery systems are needed to enhance therapeutic efficacy by selectively delivering drugs to tumor cells while minimizing off-target effects, improving treatment outcomes and reducing toxicity. In this study, a silica-based nanocarrier capable of targeting drug delivery to cancer cells was developed. First, silica nanoparticles were synthesized by the Stöber method using the surfactant cetyltrimethylammonium bromide (CTAB). Increasing the ratio of EtOH in the solvent produced uniformly spherical silica nanoparticles. Washing the nanoparticles removed unreacted residues, resulting in a non-toxic carrier for drug delivery in cells. Upon surface modification, the pH-responsive polymer, polyethyleneimine (PEI) exhibited slow doxorubicin release at pH 7.4 and accelerated release at pH 5.5. By exploiting this feature, we developed a system capable of targeted drug release in the acidic tumor microenvironment.

• Journal of Korean Neurosurgical Society
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• v.58 no.5
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• pp.487-490
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• 2015

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a relapsing-remitting disorder for which steroid administration is a key to control the progression. CLIPPERS can exhibit radiological features similar to malignant lymphoma, whose diagnosis is confounded by prior steroid administration. We report a case of CLIPPERS accompanied by abnormal elevation of ${\beta}-2$ microglobulin in the cerebrospinal fluid (CSF). A 62-year-old man started to experience numbness in all fingers of his left hand one year ago, which gradually extended to his body trunk and legs on both sides. Magnetic resonance imaging demonstrated numerous small enhancing spots scattered in his brain and spinal cord. CSF levels of ${\beta}-2$ microglobulin were elevated; although this often indicates central nervous system involvement in leukemia and lymphoma, the lesions were diagnosed as CLIPPERS based on the pathological findings from a biopsy specimen. We emphasize the importance of biopsy to differentiate between CLIPPERS and malignant lymphoma because the temporary radiological response to steroid might be the same in both diseases but the treatment strategies regarding the use of steroid are quite different.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.5
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• pp.289-293
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• 2003

Mutations in the NF2 tumor suppressor gene cause neurofibromatosis type 2, an autosomal dominant inherited syndrome predisposed to the multiple tumors of the nervous system. Merlin, the NF2 gene product was reported to block Ras-mediated cell transformation and represses Ras-induced expression of cyclin D1. However, the potential mechanism underlying the anti-Ras function of merlin on the cyclin D1 is still unclear. In this study, we investigated whether merlin decreases Ha-ras-induced accumulation of cyclin D1 at the transcriptional level, and demonstrated that merlin suppressed Ras-induced cyclin D1 promoter activity mediated by the cyclic AMP-responsive element (CRE) in SK-N-BE(2)C neuroblastoma cells. Furthermore, we found that merlin attenuated active Ras and forskolin-induced CRE-driven promoter activity. These results suggest that the transcriptional repression of the cyclin D1 expression by merlin may contribute to the inhibition of Ras-induced cell proliferation.

• Bulletin of the Korean Chemical Society
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• v.25 no.12
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• pp.1833-1839
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• 2004

Recently mass spectrometry and separation methods such as liquid chromatography have become major tools in the field of proteomics. In this report, we describe in detail our efforts to develop ultra-high pressure capillary reverse-phase liquid chromatography (cRPLC) and its online coupling to a mass spectrometer by a nanoelectrospray (nanoESI) interface. The RPLC system is constructed in house to deliver LC solvents at the pressure up to 20,000 psig, which is four times higher than conventional RPLC systems. The high operation pressure allows the efficient use of packed micro-capillary columns (50, 75 and 150 ${\mu}$m i.d., up to 1.5 m long). We will discuss the effect of column diameter on the sensitivity of cRPLC/MS/MS experiments and the utility of the developed technique for proteome analysis by its application in the analysis of proteome samples having different levels of complexity.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.11
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• pp.1010-1018
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• 2008

In this report, we describe the use of gold nanoparticles (AuNPs) immobilized on pH. responsive, cross-linked poly(4-vinylpyridine) (P4VP) thin films, as a potential application for pH nanosensors. The methodology is based on the variation in surface plasmon resonance of immobilized AuNPs with changing the interparticle distances, caused by the swelling/deswelling of the pH responsive P4VP polymer films. The change in optical properties of the immobilized AuNPs in response to the pH of surrounding media was investigated by a simple yet powerful tool; UV-vis absorption spectroscopy. The swelling of the P4VP chains at pH 2 causes an increase in the interparticle distances of immobilized AUNPS ($\sim20nm$) and hence leads to a blue shift of 48 nm in their surface plasmon resonance band peak. On the other hand, when the surrounding media was altered from pH 2 to 10, a red shift of absorption maxima was observed. The changes were rapid, and the effect was reversible. This system could prove to be useful in fabricating nanosensors for detecting the pH or pH changes of surrounding aqueous medium.

• Journal of The Korean Association For Science Education
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• v.38 no.1
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• pp.11-26
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• 2018

The purpose of this study is to investigate teachers' responsive practices in whole class discussion after small group argumentation and the underlying epistemological framing. Three teachers and 84 students participated in this study by engaging in argumentation activities about the sensory system. We recorded both their discussions in the classes and our interviews with the teachers, which were transcribed for analysis. The results of the analysis showed that the teachers' responsive practices and the epistemological framing were categorized into four types. By framing the discussion as 'reaching the correct answer through discussion,' the teacher focused on whether students' ideas corresponded to scientific concepts and transferred scientific ideas to the students. By framing the discussion as 'eliciting appropriate conceptual resources and developing them into a scientific idea through critical evaluation,' the teacher engaged in the students' discussion as another participant, and considered the small groups' arguments as resources that could develop into scientific concepts. By framing the discussion as 'sharing small groups' arguments,' the teacher responded by asking for clarification of each group's argument, considering it as a valid argument in its own way. By framing the discussion as 'reaching a consented argument through critical evaluation,' the teacher negotiated students' critical evaluation and revision of the arguments. We explored the implications and limitations of each type of responsive practice and considered that the results of this study will contribute to developing teachers' responsive teaching strategies in argumentation activities.