1,747 research outputs found
Identification of viruses infecting six plum cultivars in Korea by RNA-sequencing
No full textBackground Plums are a kind of stone fruit, a category that includes peaches, cherries, apricots, and almonds. In Korea, Japanese plum trees are usually cultivated as they best suit the climate. To date, there have been few studies in Korea on viruses infecting plum trees compared to those infecting peach trees. Methods To identify viruses and viroids infecting plum trees, we collected leaf samples from six different plum cultivars and subjected them to RNA-sequencing (RNA-seq). Six different plum transcriptomes were de novo assembled using the Trinity assembler followed by BLAST searching against a viral reference database. Results We identified hop stunt viroid (HSVd) and six viruses, including apple chlorotic leaf spot virus (ACLSV), little cherry virus-1 (LChV-1), peach virus D (PeVD), peach leaf pitting-associated virus (PLPaV), plum bark necrosis stem pitting-associated virus (PBNSPaV), and prunus necrotic ringspot virus (PNRSV), from six plum cultivars by RNA-seq. RT-PCR confirmed the infection of HSVd and three viruses—ACLSV, PBNSPaV, and PNRSV—in plum trees. However, RT-PCR demonstrated that plum trees in this study were not infected by LChV-1, PeVD, or PLPaV. It is likely that the three viruses LChV-1, PeVD, and PLPaV as identified by RNA-seq were contaminants from other peach libraries caused by index misassignment, which suggests that careful confirmation by other methods should be carried out in next-generation sequencing (NGS)-based virus identification. Taken together, we identified a viroid and three viruses infecting plum trees in Korea
Detection of broken rotor bars in induction motors using parameter and state estimation
No full textThesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1989.Includes bibliographical references (leaves 113-116).by Kyong Rae Cho.M.S
The effect of MGAT expression on cellular lipid metabolism
No full textFollowing absorption into the enterocyte, free fatty acid (FFA) and sn-2-monoacylglycerol (sn-2-MG), the major hydrolysis products of dietary lipids, are reconstituted to triacylglycerol (TG) by the monoacylglycerol acyltransferase (MGAT) pathway, which is the primary TG synthesis pathway in the postprandial condition. Nevertheless, the precise function and contribution of the MGAT pathway to lipid synthesis are not fully understood. Therefore in this study, we examined the effect of MGAT expression on cellular lipid metabolism. Although the Caco-2 cell line, which is derived from human colorectal cancer cells, is the most relevant in vitro model to examine the influence of hMGAT2 expression on lipid metabolism in the enterocyte, we could not obtain any definitive metabolism data caused by MGAT expression due to their inconsistent transfection efficiency. Thus we transiently expressed hMGAT2 in CHO-K1 cells, which are relatively easier to transfect, and these cells were then used to study the metabolism of radiolabeled FFA or sn-2-MG. Empty vector-transfected (mock) and MGAT-transfected cells, which were incubated with FA, showed the increased net uptake as a function of time, and both groups metabolized most of absorbed FA to phospholipid (PL). Between the two groups, there were no significant differences. In contrast, MGAT expressing cells which were incubated with MG, absorbed remarkably higher amounts of lipid relative to mock-transfected cells. This suggests that MGAT expression promotes the rapid uptake of MG across the membrane by efficiently maintaining concentration gradients, or that the transmembrane lipid transport proteins are influenced by MGAT expression. The incorporation of absorbed MG into each lipid class was also significantly different between mock and MGAT expressing cells. More MG was incorporated into TG and DG in the MGAT transfected cells. In addition, the MGAT expressing cells showed higher percent incorporation into PL and lower percent incorporation into TG comparing to mock expressing cells. This difference in metabolic channeling suggests that diacylglycerol (DG) synthesized from MGAT pathway may not be equivalent with DG synthesized from G-3-P pathway, which is the ubiquitous metabolic pathway used to synthesize TG in most cells. We therefore suggest that MGAT expression may increase the net uptake of lipid into cells, and that the G-3-P and MGAT pathways may have different pools of DG which are metabolized to PL or TG.M.S.Includes bibliographical referencesby Kyong Jin Ah
Improving Image Quality of a Mobilie Cone-Beam CT by use of scatter and Beam-Hardening Correction
No full textA study of the impact of organizational communication networks and personal communication technology uses on Korean immigrants’ intercultural development
No full textBased on the assumption that communication networks constitute culture, a study was conducted on the impact of organizational communication networks and personal communication technologies (PCTs) use on Korean immigrants’ intercultural development. The research has found that Korean immigrants’ structural positions within their ethnic church communication networks and diversity of their social network have significant influences on their intercultural development, of which the process is facilitated by PCT usage with distinctive ties. A theoretical model of immigrant intercultural development was suggested based on the existing theories of cross-cultural adaptation (Kim, 2001), cultural convergence (Barnett & Kincaid, 1983), and intercultural communication networks (Smith, 1999; Yum, 1988) with a communication-centered view on social networks. The current study first examined the structural composition of Korean immigrants’ communication networks in their ethnic church community, which became the main sources of their social capital, and then measured the effect of their network characteristics (i.e., size, diversity, and centrality) on individuals’ ethnorelative and ethnocentric development (for RQ1 and its related six hypotheses). An organizational member survey of a sample Korean immigrant church was used to construct the whole network of the organization and to analyze the relationships between major constructs (i.e., social capital, PCTs use, and intercultural development). Further, how those network characteristics are related to Korean immigrants’ PCTs use for contacting distinctive social ties (i.e., coethnic vs. host, strong vs. weak ties) were examined (for RQ2 and its four subsidiary questions). Last, this study examined how Korean immigrants’ social capital embedded in their communication networks and PCT usage affect their intercultural development together (i.e., RQ3) via hierarchical multiple regression modeling. As a result of data analyses, two path models for the process of intercultural development were proposed; PCTs use for coethnic strong ties appears to increase Korean immigrant’s network centrality within the ethnic religious community, which leads to ethnocentric development. By contrast, PCTs use for host ties (both strong and weak) seems to increase network diversity, which leads to ethnorelative development.Ph. D.Includes bibliographical referencesIncludes vitaby Sun Kyong Le
Comparison of Prevailing Insulin Regimens at Different Time Periods in Hospitalized Patients: A Real-World Experience from a Tertiary Hospital
No full textBACKGROUND: Prevailing insulin regimens for glycemic control in hospitalized patients have changed over time. We aimed to determine whether the current basal-bolus insulin (BBI) regimen is superior to the previous insulin regimen, mainly comprising split-mixed insulin therapy. METHODS: This was a single tertiary center, retrospective observational study that included non-critically ill patients with type 2 diabetes mellitus who were treated with split-mixed insulin regimens from 2004 to 2007 (period 1) and with BBI from 2008 to 2018 (period 2). Patients from each period were analyzed after propensity score matching. The mean difference in glucose levels and the achievement of fasting and preprandial glycemic targets by day 6 of admission were assessed. The total daily insulin dose, incidence of hypoglycemia, and length of hospital stay were also evaluated. RESULTS: Among 244 patients from each period, both fasting glucose (estimated mean±standard error, 147.4±3.1 mg/dL vs. 129.4±3.2 mg/dL, P<0.001, day 6) and preprandial glucose (177.7±2.8 mg/dL vs. 152.8±2.8 mg/dL, P<0.001, day 6) were lower in period 2 than in period 1. By day 6 of hospital admission, 42.6% and 67.2% of patients achieved a preprandial glycemic target of <140 mg/dL in periods 1 and 2, respectively (relative risk, 2.00; 95% confidence interval, 1.54 to 2.59), without an increased incidence of hypoglycemia. Length of stay was shorter in period 2 (10.23±0.26 days vs. 8.70±0.26 days, P<0.001). CONCLUSION: BBI improved glycemic control in a more efficacious manner than a split-mixed insulin regimen without increasing the risk of hypoglycemia in a hospital setting
캔두형 원자로 노심의 비선형 안정영역 해석
No full text학위논문(석사) - 한국과학기술원 : 원자력공학과, 1993.2, [ viii, 62 p. ]The asymptotic stability domain of a CANDU reactor was estimated for the various values of feedback and design parameters utilizing the expansion method. The expansion method for identifying nonlinear stability domain requires only a positive definite function and it is particularly useful for stiff systems such as a nuclear reactor. From a large starting region, the entire stability domain is estimated effectively after sufficient iterations. The dynamic equations for a CANDU reactor with four reactivity feedbacks are developed from the relation of energy balance and nonlinear analysis is performed for the steady-state solution. By analysis of bifucation theory, nonlinear phenomena are observed for various distributions of reactivity feedback coefficients. Hopf bifurcation point are situated on the dynamic stability boundary and stable limit cycles and unstable limit cycles of the steady-state solutions exist for certain values of the reactivity coefficients. We observed that feedback and design parameters change the size of the stability domain. In a CANDU reactor, the stability is determined chiefly by the extent of void at saturated state of coolant. It is noteworthy that the stability domain is scarcely affected by the moderator temperature coefficient. The stability domain increases as the fuel temperature coefficient decreases (in negative values) and the coolant temperature coefficient decreases (in positive values). As the mass flow rate of the coolant increases, the stability domain becomes large, and as the reactor power increases, the stability domain becomes small.한국과학기술원 : 원자력공학과
Identification of SYK inhibitor, R406 as a novel senolytic agent
No full textThe selective removal of senescent cells by senolytics is suggested as a potential approach to reverse aging and extend lifespan. Using high-throughput screening with replicative senescence of human diploid fibroblasts (HDFs), we identified a novel senolytic drug R406 that showed selective toxicity in senescent cells. Using flow cytometry and caspase expression analysis, we confirmed that R406 caused apoptotic cell death along with morphological changes in senescent cells. Interestingly, R406 altered the cell survival-related molecular processes including the inhibition of phosphorylation of the focal adhesion kinase (FAK) and p38 mitogen-activated protein kinase (MAPK) in senescent cells. This pattern was not observed in other known senolytic agent ABT263. Correspondingly, apoptotic cell death in senescent cells was induced by simultaneously blocking the FAK and p38 pathways. Taken together, we suggest that R406 acts as a senolytic drug by inducing apoptosis and reducing cell attachment capacity. © Cho et al.1
Efficacy and Safety of Self-Titration Algorithms of Insulin Glargine 300 units/mL in Individuals with Uncontrolled Type 2 Diabetes Mellitus (The Korean TITRATION Study): A Randomized Controlled Trial
No full textCopyright © 2022 Korean Diabetes AssociationBackground: To compare the efficacy and safety of two insulin self-titration algorithms, Implementing New Strategies with Insulin Glargine for Hyperglycemia Treatment (INSIGHT) and EDITION, for insulin glargine 300 units/mL (Gla-300) in Korean individuals with uncontrolled type 2 diabetes mellitus (T2DM). Methods: In a 12-week, randomized, open-label trial, individuals with uncontrolled T2DM requiring basal insulin were randomized to either the INSIGHT (adjusted by 1 unit/day) or EDITION (adjusted by 3 units/week) algorithm to achieve a fasting self-monitoring of blood glucose (SMBG) in the range of 4.4 to 5.6 mmol/L. The primary outcome was the proportion of individuals achieving a fasting SMBG ≤5.6 mmol/L without nocturnal hypoglycemia at week 12. Results: Of 129 individuals (age, 64.1±9.5 years; 66 [51.2%] women), 65 and 64 were randomized to the INSIGHT and EDITION algorithms, respectively. The primary outcome of achievement was comparable between the two groups (24.6% vs. 23.4%, P=0.876). Compared with the EDITION group, the INSIGHT group had a greater reduction in 7-point SMBG but a similar decrease in fasting plasma glucose and glycosylated hemoglobin. The increment of total daily insulin dose was significantly higher in the INSIGHT group than in the EDITION group (between-group difference: 5.8±2.7 units/day, P=0.033). However, body weight was significantly increased only in the EDITION group (0.6±2.4 kg, P=0.038). There was no difference in the occurrence of hypoglycemia between the two groups. Patient satisfaction was significantly increased in the INSIGHT group (P=0.014). Conclusion: The self-titration of Gla-300 using the INSIGHT algorithm was effective and safe compared with that using the EDITION algorithm in Korean individuals with uncontrolled T2DM (ClinicalTrials.gov number: NCT03406663).N
4-deoxypyridoxine improves the viability of isolated pancreatic islets ex vivo
No full textThe successful islet transplantation, for the treatment of type 1 diabetes, depends on the quantity and the quality of transplanted islets. Previously, it has reported that the significant loss of isolated islet mass could be prevented by sphingolipid metabolite, sphinogosine 1-phophate (S1P). This study was performed to elucidate whether the beneficial effects of S1P maintaining isolated pancreatic islets ex vivo are mimicked by modulation of intracellular S1P. We tested the in vitro effect of various agents that modulate intracellular S1P levels in insulinoma cell lines and isolated islets to compare their anti-apoptotic effects with that of S1P. As results, we discovered that 4-deoxypyridoxine (DOP), which inhibits the degradation of intracellular S1P by inhibiting S1P lyase (SPL) activity, minimized the chemically induced apoptosis of insulinoma cell lines as S1P did. Also, supplementation of DOP in the culture media protected the regression of isolated islets that have been maintained ex vivo at least for 18 h providing the evidence of increasing viability of isolated islets with DOP, which impaired SPL activity. In conclusion, these results suggest that the application of SPL inhibitors could be considered as a supplement for the maintenance of viable islets isolated from donor sources in the process of islet transplantation.Y
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