• Journal of Astronomy and Space Sciences
• /
• v.21 no.4
• /
• pp.283-294
• /
• 2004

New BV RI photometric observations of the contact binary AH Tau were performed with the 61 cm reflector and a 2K CCD camera at the Sobaeksan Optical Astronomy Observatory during seven nights from September to December, 2001. A total of 144 times of minima observed up to date, including three times of minima obtained from our observation, were analyzed. It is found that the orbital period of AH Tau has varied in a cyclic way superposed on a secular period decrease. The rate of the secular period decrease is calculated to be $1^s$ .04 per century, implying that a mass of about $3.8{\times}10^{-8}M{\odot}/yr$ from the more massive primary flows into the secondary if a conservative mass transfer is assumed. Assuming that the sinusoidal period variation is produced by a light-time effect due to an unseen third body, the resultant semi-amplitude, period, and eccentricity for the deduced light-time orbit are obtained as 35.4 years, 0.014 day and 0.52, respectively. The mass of the third-body is calculated as a tout $0.24M{\odot}$ when the third body is assumed to be coplanar with AH Tau system.

• Bulletin of the Korean Mathematical Society
• /
• v.47 no.1
• /
• pp.167-178
• /
• 2010

We discuss the critical points of the functional $F_{\lambda,\mu}(J,g)=\int_M(\lambda\tau+\mu\tau^*)d\upsilon_g$ on the spaces of all almost Hermitian structures AH(M) with $(\lambda,\mu){\in}R^2-(0,0)$, where $\tau$ and $\tau^*$ being the scalar curvature and the *-scalar curvature of (J, g), respectively. We shall give several characterizations of Kahler structure for some special classes of almost Hermitian manifolds, in terms of the critical points of the functionals $F_{\lambda,\mu}(J,g)$ on AH(M). Further, we provide the almost Hermitian analogy of the Hilbert's result.

• BMB Reports
• /
• v.49 no.8
• /
• pp.405-413
• /
• 2016

Tau proteins, which stabilize the structure and regulate the dynamics of microtubules, also play important roles in axonal transport and signal transduction. Tau proteins are missorted, aggregated, and found as tau inclusions under many pathological conditions associated with neurodegenerative disorders, which are collectively known as tauopathies. In the adult human brain, tau protein can be expressed in six isoforms due to alternative splicing. The aberrant splicing of tau pre-mRNA has been consistently identified in a variety of tauopathies but is not restricted to these types of disorders as it is also present in patients with non-tau proteinopathies and RNAopathies. Tau mis-splicing results in isoform-specific impairments in normal physiological function and enhanced recruitment of excessive tau isoforms into the pathological process. A variety of factors are involved in the complex set of mechanisms underlying tau mis-splicing, but variation in the cis-element, methylation of the MAPT gene, genetic polymorphisms, the quantity and activity of spliceosomal proteins, and the patency of other RNA-binding proteins, are related to aberrant splicing. Currently, there is a lack of appropriate therapeutic strategies aimed at correcting the tau mis-splicing process in patients with neurodegenerative disorders. Thus, a more comprehensive understanding of the relationship between tau mis-splicing and neurodegenerative disorders will aid in the development of efficient therapeutic strategies for patients with a tauopathy or other, related neurodegenerative disorders.

• Bulletin of the Korean Space Science Society
• /
• 2002.05b
• /
• pp.17.2-17
• /
• 2002

• Applied Chemistry for Engineering
• /
• v.24 no.2
• /
• pp.177-183
• /
• 2013

In this study, the antioxidative activities and component analysis of Broussonetia kazinoki SIEB (B. kazinoki). extracts were investigated. B. kazinoki extract showed the effective free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activity ($FSC_{50}=8.53{\mu}g/mL$). Reactive oxygen species (ROS) scavenging activity ($OSC_{50}$) of the ethyl acetate fraction of B. kazinoki. extracts in the luminol-dependent $Fe^{3+}-EDTA/H_2O_2$ system was $1.69{\mu}g/mL$. The ethyl acetate fraction of B. kazinoki. extracts also exhibited more prominent cellular protective effects (${\tau}_{50}$, 183.3 min at $10{\mu}g/mL$) than that of typical antioxidant $\alpha$-tocopherol (${\tau}_{50}$ = 38.00 min) in the $^1O_2$-induced photohemolysis of human erythrocytes. Components of the ethyl acetate fraction obtained from B. kazinoki extracts were analyzed by TLC, HPLC chromatogram, LC/ESI-MS/MS and $^1H$-NMR. Consequently, Components, components were identified as the kazinol J of kazinol series and luteolin (2-(3,4-dihydroxyphenyl)-5,7-dihydroxy-4-chromenone) of flavonoid series having antioxidant activities. These results indicate that extract/ fraction of B. kazinoki can be used as antioxidants in biological systems, particularly skins exposed to UV radiation by quenching and/or scavenging $^1O_2$ and other ROS, and protecting cellular membranes against ROS. Thus, the extract/fraction of B. kazinoki could be applicable to new cosmeceuticals.

• Journal of Korean Academy of Nursing
• /
• v.53 no.4
• /
• pp.371-384
• /
• 2023

Purpose: With an increase in the aging population, the number of patients with degenerative spinal diseases undergoing surgery has risen, as has the incidence of postoperative delirium. This study aimed to investigate the risk factors affecting postoperative delirium in older adults who had undergone spine surgery and to identify the associated biomarkers. Methods: This study is a prospective study. Data of 100 patients aged ≥ 70 years who underwent spinal surgery were analyzed. Demographic data, medical history, clinical characteristics, cognitive function, depression symptoms, functional status, frailty, and nutritional status were investigated to identify the risk factors for delirium. The Confusion Assessment Method, Delirium Rating Scale-R-98, and Nursing Delirium Scale were also used for diagnosing delirium. To discover the biomarkers, urine extracellular vesicles (EVs) were analyzed for tau, ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), neurofilament light, and glial fibrillary acidic protein using digital immunoassay technology. Results: Nine patients were excluded, and data obtained from the remaining 91 were analyzed. Among them, 18 (19.8%) developed delirium. Differences were observed between participants with and without delirium in the contexts of a history of mental disorder and use of benzodiazepines (p = .005 and p = .026, respectively). Tau and UCH-L1-concentrations of urine EVs-were comparatively higher in participants with severe delirium than that in participants without delirium (p = .002 and p = .001, respectively). Conclusion: These findings can assist clinicians in accurately identifying the risk factors before surgery, classifying high-risk patients, and predicting and detecting delirium in older patients. Moreover, urine EV analysis revealed that postoperative delirium following spinal surgery is most likely associated with brain damage.

• Bulletin of the Korean Space Science Society
• /
• 2008.10a
• /
• pp.23.2-23.2
• /
• 2008

We presented the accurate absolute dimensions and distances of fifteen main sequence eclipsing binaries. The photometric and spectroscopic solutions of the binary systems were determined by analyzing light curves and radial velocity curves collected from the literature using the Wilson-Devinney computer code. The fifteen double-line spectroscopic binaries consist of nine detached systems; QX Car, AH Cep, CW Cep, ZZ Cep, XY Cet, RX Her, V451 Oph, VV Pyx and V760 Sco, six semi-detached systems; LY Aur, IU Aur, AO Cas, DM Per, V Pup and HU Tau. The temperatures of the binary systems were determined from their colors using the color-temperature calibrations. Then the temperature of each component star were determined using the temperature ratio which was adjusted from the light curves. We estimated the possible Z values and ages for the detached systems by adopting the Y2 (Yonsei-Yale) stellar evolutionary tracks. The derived distances are in good agreement of the Hipparcos distances whose error of parallax is within 10 %. Finally these well-investigated systems will be used as the standard eclipsing binaries.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.41 no.2
• /
• pp.181-187
• /
• 2015

In this study, the methanol fraction and aglycone fraction were made from Gynura procumbens (G. procumbens) extracts and their antioxidative effects were investigated. The free radical scavenging activity (1,1-diphenyl-2-picrylhydrazyl, DPPH), total antioxidant capacity by luminol-dependent chemiluminescence assay, and the protective effects against reactive oxygen species (ROS) in erythrocytes were measured to evaluate the antioxidative activities of the extracts. Free radical scavenging activities ($FSC_{50}$) of the methanol fraction and aglycone fraction were 90.25 and $81.38{\mu}g/mL$, respectively. Total antioxidant capacities ($OSC_{50}$) of the methanol fraction and aglycone fraction were 16.96 and $12.30{\mu}g/mL$, respectively. The free radical scavenging activity and total antioxidant capacity of the aglycone fraction were greater than those of methanol fraction. The cellular protective effect on the $^1O_2$-induced cellular damage of human erythrocytes was confirmed by ${\tau}_{50}$ value. The ${\tau}_{50}$ value of the methanol fraction and aglycone fraction were 36.7 min and 76.1 min, respectively in $5{\mu}g/mL$, and the aglycone fraction showed about 2 times higher cellular protecive effect than (+)-${\alpha}$-tocopherol (35.4 min). These results indicate that the aglycone fraction of G. procumbens extracts has application possibility as antioxidant ingredient of cosmetic.

• Korean Journal of Pharmacognosy
• /
• v.47 no.3
• /
• pp.251-257
• /
• 2016

In this study, the radical scavenging activity and protective effect of ethanol extract from leaf of Engelhardtia chrysolepis HANCE (ECE) against oxidative stress were investigated under in vitro and cellular system. ECE showed strong radical scavenging activities in 1,1-diphenyl-2-picrylhydrazyl, hydroxyl(${\cdot}OH$) and nitric oxide(NO) radical as a concentration-dependent manner. Particularly, strong scavenging activity against the ${\cdot}OH$ and NO radical were observed with the $IC_{50}$ value of $1.30{\mu}g/ml$ and $12.61{\mu}g/ml$, respectively. Furthermore, the cellular oxidative stress was induced by amyloid beta($A{\beta}_{25-35}$) in C6 glial cells. The treatment of $A{\beta}_{25-35}$ to C6 glial cells generated high levels of reactive oxygen species(ROS) and declined cell viability. However, production of ROS was decreased by the treatment of ECE. In addition, the cell viability was significantly increased at each concentration(10, 25, $50{\mu}g/ml$) as dose-dependent manner. The Alzheimer's disease-related protein expressions in $A{\beta}_{25-35}$-treated C6 glial cells were analyzed. The ECE treatment inhibited expression of amyloid precursor protein(APP), C-terminal fragment-${\beta}(CTF-{\beta})$, ${\beta}$-site APP cleaving enzyme(BACE), phosphorylated tau(p-tau) proteins in C6 glial cells induced by $A{\beta}_{25-35}$. The present study indicated that ECE has strong radical scavenging activity and neuroprotective effect through attenuating oxidative stress.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.37 no.4
• /
• pp.357-363
• /
• 2011

In this study, the antioxidative effects and inhibitory activities on tyrosinase of Rheum undulatum (R.undulatum) L. extracts were investigated. 50 % ethanol extract, ethyl acetate and aglycone fractions of R. undulatum L. were used in experiments. The DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging activities ($FSC_{50}$) of R. undulatum L. extracts was lower than (+)-${\alpha}$-tocopherol, known as a typical antioxidant. Reactive oxygen species (ROS) scavenging activities ($OSC_{50}$) of aglycone fraction on ROS generated in $Fe^{3+}$-EDTA/$H_2O_2$ system using the luminol-dependent chemiluminescence assay showed the most prominent effect at a concentration of $0.265\;{\mu}g/mL$. The cellular protective effects of extract/fractions of R. undulatum L. on the rose-bengal sensitized photohemolysis of human erythrocytes were increased in a concentration dependent manner ($1{\sim}50\;{\mu}g/mL$). Especially, aglycone fraction in $10\;{\mu}g/mL$ concentration showed the most protective effect among extracts (${\tau}_{50}$, 757.0 min). The inhibitory effects ($IC_{50}$, $11.20\;{\mu}g/mL$) on tyrosinase of aglycone fraction was much higher than arbutin ($226.88\;{\mu}g/mL$), known as a whitening agent. These results indicate that R. undulatum L. extracts can be used as antioxidant. Particularly, aglycone fraction of R. undulatum L. showed superior antioxdative activity and high inhibitory effect on tyrosinase. Therefore, aglycone fraction of R. undulatum L. could be applicable to new functional cosmetics.