• 한국분말재료학회지
• /
• 제15권6호
• /
• pp.466-470
• /
• 2008

Experiments with a URT-0.5 accelerator (0.5 MeV, 50 ns, 1 kW) generating a nanosecond electron beam for irradiation of silver nitrate in various liquid solutions (water and toluene) were performed with the aim of producing silver nanopowders. A radiochemical reaction allows making weakly agglomerated pure Ag powders with particles of 10-15 nm and 30-50 nm in size by irradiation in toluene and water respectively. The injection of the nanosecond electron beam energy to the solution is optimal. As the absorbed dose increases, the output of the radiochemical reaction does not grow, but more agglomerated powders are synthesized.

• Nutrition Research and Practice
• /
• 제17권2호
• /
• pp.192-205
• /
• 2023

BACKGROUND/OBJECTIVES: It is known that the renin-angiotensin system (RAS) in the brain could regulate cognitive functions as well as blood pressure. Inhibition of RAS for the improvement of cognitive function may be a new strategy, but studies so far have mostly reported on the effects of RAS inhibition by drugs, and there is no research on cognitive improvement through RAS inhibition of food ingredients. Therefore, this study investigated the effect of curcumin on blood pressure and cognitive function and its related mechanism in spontaneously hypertensive rat/Izm (SHR/Izm). MATERIALS/METHODS: Six-week-old SHR/Izm rats were divided into 5 groups: control group (CON), scopolamine group (SCO, drug for inducing cognitive deficits), positive control (SCO and tacrine [TAC]), curcumin 100 group (CUR100, SCO + Cur 100 mg/kg), and curcumin 200 group (CUR200, SCO + Cur 200 mg/kg). Changes in blood pressure, RAS, cholinergic system, and cognitive function were compared before and after cognitive impairment. RESULTS: The SCO group showed increased blood pressure and significantly reduced cognitive function based on the y-maze and passive avoidance test. Curcumin treatments significantly improved blood pressure and cognitive function compared with the SCO group. In both the CUR100 and CUR200 groups, the mRNA expressions of angiotensin-converting enzyme (ACE) and angiotensin II receptor type1 (AT1), as well as the concentrations of angiotensin II (Ang II) in brain tissue were significantly decreased. The mRNA expression of the muscarinic acetylcholine receptors (mAChRs) and acetylcholine (ACh) content was significantly increased, compared with the SCO group. CONCLUSIONS: The administration of curcumin improved blood pressure and cognitive function in SCO-induced hypertensive mice, indicating that the cholinergic system was improved by suppressing RAS and AT1 receptor expression and increasing the mAChR expression.

• 한국응용약물학회:학술대회논문집
• /
• 한국응용약물학회 1993년도 제1회 추계심포지움 and 제2회 생리분자과학연구센터워크숍
• /
• pp.28-33
• /
• 1993

Regulation of nerve growth factor (NGF)-induced neuronal differentiation by GTPase activating protein(GAP) and its mechanism were investigated in rat pheochromocytoma cell line, PCl2. Overexpression of GAP caused the delay in the onset of neurite outgrowth of PCl2 eel Is in response to NGF. GAP has been known to inhibit p21$\^$ras/, the activated form of which induces neuronal differentiation. Therefore, the activity of p21$\^$ras/ was compared in control cells and cells overexpressing GAP indirectly by measuring the activities of B-Raf and MAP kinase that are known to be positively regulated by p21$\^$ras/. Surprisingly, NGF-induced activities of these two proteins were the same in control eells and GAP-overexpressing cells. Activities of Trk, PLC-r and SMC that act at a site upstream to p21$\^$ras/ in NGF signal transduction pathway were not also affected by GAP overexpression. Interestingly, however, the extent of tyrosine phosphorylation of SNT was found to be remarkably low in cells overexpressing GAP. It has been shown previously that neurotrophins and not mitogens induce SNT tyrosine phosphorylation in PCl2 cells. Thus it is possible that the timing of NGF-induced neuronal differntiation may be in part regulated by SNT and the slower onset of neurite outgrowth in cells overexpressing GAP may be through the inhibition of SNT by GAP.

• Ecology and Resilient Infrastructure
• /
• 제7권4호
• /
• pp.353-365
• /
• 2020

본 연구에서는 낙동강을 대상으로 HEC-RAS를 이용하여 보 개방에 따른 하상변동 특성을 분석하였다. 연구 대상 지역은 낙동강 구담교 하류부터 하구둑까지 292.37 km 구간이다. 하상변동 모의를 위하여 1차원 수치해석모델인 HEC-RAS 프로그램을 사용하였으며 2017년도부터 2019년도까지 2가지의 시나리오로 모의를 수행하였다. 시나리오 1은 수문 전면 개방의 조건으로 구축하였으며 시나리오 2는 수문이 설치된 조건으로 모의를 수행하였다. 모의결과, 시나리오 1의 조건에서 합천창녕보 - 창녕함안보 대부분의 구간 (약 40 km)에서 퇴적이 발생한 것을 확인하였다. 또한 낙동강 본류 내의 유사를 포함한 흐름이 보 구조물로 인해 단절되지 않고 연속적으로 하상을 변동시키는 것으로 예측되었다.

• 한국미생물학회:학술대회논문집
• /
• 한국미생물학회 2006년도 International Meeting of the Microbiological Society of Korea
• /
• pp.69-71
• /
• 2006

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권11호
• /
• pp.6261-6265
• /
• 2013

Background: Recent studies have suggested that expression of the RAS protein activator like-1 gene (RASAL1) is decreased in gastric carcinoma tissues and cell lines, indicated a role in tumorigenesis and development of gastric cancer. Reduced expression of RASAL1 could result in aberrant increase of activity of RAS signaling pathways in cancer cells. However, the exact mechanism which induces down-regulation of the RASAL1 gene remains unclear. This study aimed to determine the methylation status and regulation of RASAL1 in gastric cancer. Materials and Methods: Using the methylation-specific polymerase chain reaction (MSP), the methylation status of CpG islands in the RASAL1 promoter in gastric cancers and paired adjacent non-cancerous tissues from 40 patients was assessed and its clinicopathological significance was analyzed. The methylation status of RASAL1 in gastric cancer lines MKN-28, SGC-790l, BGC-823, as well as in normal gastric epithelial cell line GES-l was also determined after treatment with a DNA methyltransferase inhibitor, 5-aza-2'-doexycytidine (5-Aza-CdR). RAS activity (GAS-GTP) was assessed through a pull-down method, while protein levels of ERK1/2, a downstream molecule of RAS signaling pathways, were determined by Western blotting. Results: The frequencies of RASAL1 promoter methylation in gastric cancer and paired adjacent non-cancerous tissues were 70% (28/40) and 30% (12/40) respectively (P<0.05). There were significantly correlations between RASAL1 promoter methylation with tumor differentiation, tumor size, invasive depth and lymph node metastasis in patients with gastric cancer (all P<0.05), but no correlation was found for age or gender. Promoter hypermethylation of the RASAL1 gene was detected in MKN-28, SGC-790l and BGC-823 cancer cells, but not in the normal gastric epithelial cell line GES-1. Elevated expression of the RASAL1 protein, a decreased RAS-GTP and p-ERK1/2 protein were detected in three gastric cancer cell lines after treatment with 5-Aza-CdR. Conclusions: Aberrant hypermethylation of the RASAL1 gene promoter frequently occurs in gastric cancer tissues and cells. In addition, the demethylating agent 5-Aza-CdR can reverse the hypermethylation of RASAL1 gene and up-regulate the expression of RASAL1 significantly in gastric cancer cells in vivo. Our study suggests that RASAL1 promoter methylation may have a certain relationship with the reduced RASAL1 expression in gastric cancer.

• 대한조현병학회지
• /
• 제24권1호
• /
• pp.17-25
• /
• 2021

Objectives: To examine the opinions regarding recovery and assess their will to recover in outpatients with schizophrenia. Methods: Total 98 stable outpatients with schizophrenia were enrolled. To investigate the outpatients' opinions regarding recovery, we asked the subjects to write down the ways they could think they had recovered from their current disease. We classified their answers and chose final 39 statements. Using this questionnaire, they were asked to what extent they agreed with each statement. Moreover, the Recovery Assessment Scale (RAS) was used to measure the subjects' will to recover. Results: Many of the 39 subjects who were surveyed about their opinions on recovery agreed on 11 statements about taking medicine, social life, daily life, social functioning, positivity about life (happiness, hope, confidence, and tranquility), symptoms, occupation, and self-control. The RAS score showed a significant correlation with age (r=-0.26, p<0.01), age at onset (r=0.26, p<0.01), duration of illness (r=-0.52, p<0.01), and number of hospitalization (r=-0.46, p<0.01). Conclusion: This study shows that positivity about life is an important part of the patients' subjective recovery criteria in schizophrenia. Therefore, if clinicians pay more attention to this part of subjective recovery, it would strengthen the patients' will for recovery.

• The Korean Journal of Physiology and Pharmacology
• /
• 제6권2호
• /
• pp.127-130
• /
• 2002

The present study was aimed to investigate whether the adriamycin-induced nephrosis is associated with an altered regulation of local renin-angiotensin system (RAS) in the kidney. Rats were subjected to a single injection of adriamycin (2 mg/kg body weight, IV) and kept for 6 weeks to allow the development of nephrosis. They were then divided into two groups, and supplied with and without cilazapril, an angiotensin converting enzyme (ACE) inhibitor, in drinking water (100 mg/l) for additional 6 weeks. Another group without adriamycin-treatment served as control. The mRNA expression of renin, ACE, type 1 and type 2 angiotensin II receptors (AT1R, AT2R), and transforming growth factor $(TGF)-{\beta}1$ was determined in the cortex of the kidney by reverse transcription-polymerase chain reaction. Adriamycin treatment resulted in heavy proteinuria. Accordingly, the mRNA expression of renin, ACE, and AT1R was increased in the renal cortex, while that of AT2R was decreased. Co-treatment with cilazapril attenuated the degree of proteinuria. While not affecting the altered expression of renin, cilazapril decreased the expression of ACE to the control level. Cilazapril further increased the expression of AT1R, while it restored the decreased expression of AT2R. The expression of $(TGF)-{\beta}1$ was increased by the treatment with adriamycin, which was abolished by cilazapril. An altered expression of local RAS components may be causally related with the development of adriamycin-induced nephrosis, in which AT1R is for and AT2R is against the development of nephrosis.

• Fisheries and Aquatic Sciences
• /
• 제13권2호
• /
• pp.150-156
• /
• 2010

The separation performance of a low-pressure hydrocyclone (LPH) was evaluated for suspended-solids removal in a recirculating aquaculture system (RAS). The dimensions of the LPH were 335 mm cylinder diameter, 575 mm cylinder height, 60 mm overflow diameter, 50 mm underflow diameter, and $68^{\circ}$ cone angle. The inflow rate varied (400, 600, 800, and 1,000 mL $s^{-1}$) with 25%, 25%, 20%, and 10% of bypass ($R_f$), respectively. The maximum total separation efficiency (Et) and reduced separation efficiency (E't) for suspended solids from the effluent of the second settlement tank (before biofiltration) were 58.9% and 45.2%, respectively, at an inflow rate of 600 mL $s^{-1}$ and 25% of $R_f$. The maximum Et and E't for suspended solids from the water supply channel (after biofiltration) were 24.4% and 16%, respectively, at an inflow rate of 1,000 mL $s^{-1}$ and 10% of $R_f$. The maximum grade efficiency (Ei) was 51.6% for a 300 ${\mu}m$ particle size at an inflow rate of 600 mL $s^{-1}$ with 23% of $R_f$. The maximum reduced grade efficiency (E'i) was 37.6% for a 300 ${\mu}m$ particle size at an inflow rate of 1,000 mL $s^{-1}$ with 11% of $R_f$. The results indicate that the separation performance of the LPH for suspended solids removal was size selective and that maximum removal occurred at particle sizes ranging from 300 to 500 ${\mu}m$.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
• /
• pp.235-238
• /
• 1996

In this paper, a new optimization method which is a kind of random searching is presented. The proposed method is called RasVal which is an abbreviation of Random Search Method with Variable Seaxch Length and it can search for a global minimum based on the probability density functions of searching, which can be modified using informations on success or failure of the past searching in order to execute intensified and diversified searching. By applying the proposed method to a nonlinear crane control system which can be controlled by the Universal Learning Network with radial basis function(R.B.P.), it has been proved that RasVal is superior in performance to the commonly used back propagation learning algorithm.