• Journal of Sensor Science and Technology
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• v.4 no.4
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• pp.29-40
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• 1995

In this paper, the noise equivalent cicuits that is necessary to the formulation of D.C. and noise characteristics, residual component and input capacitance so as to analyze on the noise factors of the SIT is proposed. The simplest noise equivalent circuit is the model representing the mechanism of the SIT and the measured values in this model were found as small as the values of the shot-noise. In the source resistance inserted equivalent circuit is conformed that the shot-noise will be reduced by the negative-feedback effect of the source resistance. In oder to analyze the correct noise reduction factor, I proposed the equivalent circuit which the formulas of the source and drain resistance was induced. In the experiment which affirm the equivalent circuits, the influence of the signal source resistance and output load resistance on the residual component is small and the residual component can be expressed by the equivalent input noise resistance. Moreover, the input capacitance is 13.6 pF when the load resistance is $0{\Omega}$ and the capacitance which does not concern with the SIT operation directly, that is, gate wire etc, is 10pF or so.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.4
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• pp.413-421
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• 2014

Corticotropin-releasing factor (CRF) is involved in the stress response and there is increasing evidence that stress influences skin disease such as hair loss. In cultured human hair follicles, CRF inhibits hair shaft elongation, induces premature regression and promotes the apoptosis of hair matrix keratinocytes. We investigated whether CRF influences the dermal papilla cells (DPC) that play pivotal roles in hair growth and cycling. Human DPCs were treated with CRF, adrenocorticotropic hormone (ACTH) and cortisol, key stress hormones along the hypothalamic-pituitary -adrenal (HPA) axis for 1-24 h. Interestingly, CRF modulated the expression of cytokines related to hair growth (KGF, Wnt5a, $TGF{\beta}-2$, Nexin) and increased cAMP production in cultured DPCs. CRF receptors were down-regulated by negative feedback systems. Pretreatment of CRF receptor antagonists or protein kinase A (PKA) inhibitor prevented the CRF-induced modulation. Since the CRF induces proopiomelanocortin (POMC) expression through the cAMP/PKA pathway, we analyzed POMC mRNA. CRF stimulated POMC expression in cultured human DPCs, yet we were unable to detect ACTH levels by western blot. These results indicate that CRF operates within DPCs through CRF receptors along the classical CRF signaling pathway and CRF receptor antagonists could serve as potential therapeutic and cosmetic agents for stress-induced hair loss.

• Biomolecules & Therapeutics
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• v.24 no.2
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• pp.132-139
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• 2016

The endothelial-mesenchymal transition (EndMT) is known to be involved in the transformation of vascular endothelial cells to mesenchymal cells. EndMT has been confirmed that occur in various pathologic conditions. Transforming growth factor ${\beta}1$ (TGF-${\beta}1$) is a potent stimulator of the vascular endothelial to mesenchymal transition (EMT). Aspirin-triggered resolvin D1 (AT-RvD1) has been known to be involved in the resolution of inflammation, but whether it has effects on TGF-${\beta}1$-induced EndMT is not yet clear. Therefore, we investigated the effects of AT-RvD1 on the EndMT of human umbilical vein vascular endothelial cells line (HUVECs). Treatment with TGF-${\beta}1$ reduced the expression of Nrf2 and enhanced the level of F-actin, which is associated with paracellular permeability. The expression of endothelial marker VE-cadherin in HUVEC cells was reduced, and the expression of mesenchymal marker vimentin was enhanced. AT-RvD1 restored the expression of Nrf2 and vimentin and enhanced the expression of VE-cadherin. AT-RvD1 did also affect the migration of HUVEC cells. Inhibitory ${\kappa}B$ kinase 16 (IKK 16), which is known to inhibit the NF-${\kappa}B$ pathway, had an ability to increase the expression of Nrf2 and was associated with the inhibition effect of AT-RvD1 on TGF-${\beta}1$-induced EndMT, but it had no effect on TGF-${\beta}1$-induced EndMT alone. Smad7, which is a key regulator of TGF-${\beta}$/Smads signaling by negative feedback loops, was significantly increased with the treatment of AT-RvD1. These results suggest the possibility that AT-RvD1 suppresses the TGF-${\beta}1$-induced EndMT through increasing the expression of Smad7 and is closely related to oxidative stress.

• Molecular & Cellular Toxicology
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• v.5 no.3
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• pp.193-197
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• 2009

Suppressors of cytokine signaling (SOCS) proteins were originally identified as negative feedback regulators of cytokine signaling and include the Janus kinase/Signal transducer and activator of transcription (JAK/STAT) pathways. Recent studies have shown that SOCS proteins negatively regulate the receptor tyrosine kinase (RTK) pathway including the insulin receptor (IR), EGFR, and KIT signaling pathways. In addition, SOCS1 and SOCS3 have been reported to have anti-tumor effects in human hepatocellular carcinoma (HCC). However, it is uncertain whether other members of the SOCS family are associated with tumor development and progression. In this study, to investigate whether SOCS6 is aberrantly regulated in HCC, we examined the expression level of SOCS6 in HCC by Western blot analysis and immunohistochemical staining. The results showed that SOCS6 was down-regulated in all examined HCCs compared to the corresponding normal tissues. In addition, expression of SOCS6 was observed in the cytoplasm of most normal and precancerous tissue, but not in the HCCs by immunohistochemical staining. This is first report to demonstrate that SOCS6 is aberrantly regulated in HCC. These findings suggest that underexpression of SOCS6 is involved in hepatocarcinogenesis, and SOCS6 may play a role, as a tumor suppressor, in HCC development and progression.

• IMMUNE NETWORK
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• v.10 no.6
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• pp.219-229
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• 2010

Background: N-myc downstream regulated gene 2 (NDRG2) is a member of the NDRG gene family. Our previous report indicated a possible role for NDRG2 in regulating the cytokine, interleukin-10 (IL-10), which is an important immunosuppressive cytokine. Several pathways, including p38-MAPK, NF-${\kappa}B$, and JAK/STAT, are used for IL-10 production, and the JAK/STAT pathway can be inhibited in a negative feedback loop by the inducible protein, SOCS3. In the present study, we investigated the effect of NDRG2 gene expression on IL-10 signaling pathway that is modulated via SOCS3 and STAT3. Methods: We generated NDRG2-overexpressing U937 cell line (U937-NDRG2) and treated the cells with PMA to investigate the role of NDRG2 in IL-10 production. U937 cells were also transfected with SOCS3- or NDRG2-specific siRNAs to examine whether the knockdown of SOCS3 or NDRG2 influenced IL-10 expression. Lastly, STAT3 and SOCS3 induction was measured to identify the signaling pathway that was associated with IL-10 production. Results: RT-PCR and ELISA assays showed that IL-10 was increased in U937-mock cells upon stimulation with PMA, but IL-10 was inhibited by overexpression NDRG2. After PMA treatment, STAT3 phosphorylation was decreased in a time-dependent manner in U937-mock cells, whereas it was maintained in U937-NDRG2 cells. SOCS3 was markedly reduced in U937-NDRG2 cells compared with U937-mock cells. IL-10 production after PMA stimulation was reduced in U937 cells when SOCS3 was inhibited, but this effect was less severe when NDRG2 was inhibited. Conclusion: NDRG2 expression modulates SOCS3 and STAT3 activity, eventually leading to the inhibition of IL-10 production.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.3
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• pp.685-690
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• 2013

This paper has proposed a multi-channel and wide gain-range baseband circuit blocks for the IEEE 802.15.4g MR-OFDM SUN systems. The proposed baseband circuit blocks consist of two negative-feedback VGAs, an active-RC 5th-order chebyshev low-pass-filter, and a DC-offset cancellation circuit. The proposed baseband circuit blocks provide 1 dB cut-off frequencies of 100 kHz, 200 kHz, 400 kHz, and 600 kHz respectively, and achieve a wide gain-range of +7 dB~+84 dB with 1 dB step. In addition, a DC-offset cancellation circuit has been adopted to mitigate DC-offset problems in direct-conversion receiver. Simulation results show a maximum input differential voltage of $1.5V_{pp}$ and noise figure of 42 dB and 37.6 dB at 5 kHz and 500 kHz, respectively. The proposed I-and Q-path baseband circuits have been implemented in $0.18-{\mu}m$ CMOS technology and consume 17 mW from a 1.8 V supply voltage.

• The Journal of Pediatrics of Korean Medicine
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• v.25 no.1
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• pp.90-110
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• 2011

Objectives: The purpose of this study is to examine the parental recognition and utilizing patterns of oriental medical care in children who live in Seong-Dong district. Methods 802 day-care center children's parents participated in the survey on recognition and utilizing patterns of oriental medical care, and 702 of the surveys were analyzed. Results: 1. 38.33% has received previous oriental medical treatments and most were received at the children's age under 12-24 months. Majority of the treatments took place in the clinical settings. By recommendation, some also received their treatment at the medical centers. One of the reasons why they receive oriental medical treatments was that they prefer to balance their treatment with the orental medical treatments along with the western's. 2. 53.85% of those who received oriental medical treatments were satisfied with their treatments. The effective treatment results were the major reason for the satisfaction. 3. 49.56% of those who had oriental medical treatments chose specific oriental medical facilities for the children's ailment. Most specific oriental medical facilities were local oriental medical clinics. Reputation fame were the main reason in choosing the clinics. 4. In 2009, 55.26% had received care in the specific oriental medical clinics for the diseases, such as respiratory symptoms, systemic symptoms, gastrointestinal symptoms, skin problems, neurological and psychiatric disease for infants, and respiratory symptoms, gastrointestinal symptoms, systemic symptoms, skin problems, neurological and psychiatric symptoms, urinary symptoms and musculoskeletal symptoms for toddlers. 5. The average duration of herbal treatment were 7-14 days, preferably 4-6 days, and preferred number of medical visits were once a week on Saturdays and preferred day for night cares were on Friday nights. Average treatment fee per treatment was less than 10,000 won which coincided with the preferred treatment fee per visit. 6. The very first medical institutions chosen by parents once their children are ill are the following; Western medical institutions, western medical clinics, pharmacies, oriental medical clinics, health centers, and lastly, oriental medical institutions. The major concerns in receiving oriental medical cares include pesticides in herbs and hazardous substances in heavy metals. Preferred form of oriental medicine was decoction, the negative feedback of oriental medicine was mostly due to the bitter taste of the oriental herbal decoctions. Preferred frequency of intake was twice a day with less than 10cc~20cc per single intake. Conclusions: Taken all together, we conclude that the growing recognition of Oriental Pediatric medicine is needed among parents.

• Analytical Science and Technology
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• v.30 no.1
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• pp.10-19
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• 2017

Anabolic steroids have similar structures to testosterone, both of which promote the growth of muscle mass and increase strength. However, the side effects of anabolic steroid use may lead to heart attacks or strokes. Additionally, the excessive use of steroids inhibits the production of the sex hormones in the body via a negative feedback loop, which results in testicular atrophy in males and amenorrhea in females. Currently, the method of choice used to test for the presence of anabolic steroids is GC-MS. However, GC-MS methods require chemical derivatization of the steroid sample to ensure compatibility with the analytical method; therefore, analysis of many different samples is difficult and time consuming. Unlike GC-MS, the liquid chromatography-quadrupole-time of flight mass spectrometry (LC-Q-TOF-MS) method is suitable for many samples. Twenty-two different anabolic steroids were analyzed by LC-Q-TOF-MS with various collision energies (CE). Accurate mass spectral data were obtained using a Q-TOF-MS equipped with an electro-spray ionization source and operated in the positive MS/MS mode for several classes of steroids that are often the targets of testing. Based on the collected data, fragmentation pathways were carefully elucidated. The high selectivity and sensitivity of the LC-Q-TOF-MS instrument combined with these fragmentation pathways offers a new approach for the rapid and accurate screening of anabolic steroids. The obtained data from the 22 different anabolic steroids will be shared with the scientific community in order to establish a library to aid in the screening of illegal anabolic steroids.

• Journal of the Korea Institute of Building Construction
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• v.11 no.6
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• pp.567-575
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• 2011

With the development of construction information, a computerization tool for architectural process control is a necessary tool. However, the reality is that the conditions and understanding of users are not sufficient to fully utilize such a tool. In particular, it was analyzed that the reason for the negative feedback from hands-on workers regarding the current process control information system is that there is a difficulty in accessing the system for users that are not process and planning experts, due to a lack of information and technical contents at the phase of control and planning prior to the process plan. Therefore, the demands of users and a direction for the improvement of a system in terms of optimizing process control computerization were investigated, with the aim of addressing the disadvantages of the existing system and developing a professional system that is specialized in the construction industry. Therefore, it is necessary to construct an integrated WBS (IWBS) that combines WBS with CBS, and subsequently, it is judged that the most important aspect is the integrated technology of compatibility and operation of data that is linked with OBS. The process information must then deal with the changing information; in other words, the amount of construction, construction cost, and the required construction period etc., by coding data into a 4-unit index, such as a project unit (WBS Level 1), a project facility unit (WBS Level 2), a management department unit (OBS Level 1), and a control manager unit (OBS Level 2). After that, it was found that it is necessary to develop a computer system to consistently integrate process information into a management department.

• KSBB Journal
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• v.24 no.3
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• pp.217-226
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• 2009

p53 undergoes various post-translational modifications, including phosphorylation, ubiquitination, sumoylation, acetylation, methylation, and poly(ADP-ribosyl)ation. Modification of p53 widely affects to various functions of p53. Acetylation and phosphorylation of p53 have been studied for regulating its transcriptional activity which is observed in various stress condition. Otherwise, ubiquitination of p53 by Mdm2 has been well-studied as a canonical ubiquitin-mediated proteasomal degradation pathway. Moreover several investigators have recently reported that ubiquitination of p53 modulates not only its proteasome-dependent degradation by poly-ubiquitination but also its localization and transcriptional activity by mono-ubiquitination which usually does not serve the proteasome dependent degradation. Here we review recent studies on the cellular functions of p53 regulated by post-translational modifications, particularly focusing on mechanisms of ubiquitination.