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101.
Se-Hui Jung Hee-Young Heo Jung-Won Choe Jaehyun Kim Kooyeon Lee 《Molecules (Basel, Switzerland)》2021,26(10)
Velutin, one of the flavones contained in natural plants, has various beneficial activities, such as skin whitening, as well as anti-inflammatory, anti-allergic, antioxidant, and antimicrobial activities. However, the relationship between the structure of velutin and its anti-melanogenesis activity is not yet investigated. In this study, we obtained 12 velutin derivatives substituted at C5, C7, C3′, and C4′ of the flavone backbone with hydrogen, hydroxyl, and methoxy functionalities by chemical synthesis, to perform SAR analysis of velutin structural analogues. The SAR study revealed that the substitution of functional groups at C5, C7, C3′, and C4′ of the flavone backbone affects biological activities related to melanin synthesis. The coexistence of hydroxyl and methoxy at the C5 and C7 position is essential for inhibiting tyrosinase activity. However, 1,2-diol compounds substituted at C3′ and C4′ of flavone backbone induce apoptosis of melanoma cells. Further, substitution at C3′ and C4′ with methoxy or hydrogen is essential for inhibiting melanogenesis. Thus, this study would be helpful for the development of natural-derived functional materials to regulate melanin synthesis. 相似文献
102.
Pritam-Bhagwan Bhosale Preethi Vetrivel Sang-Eun Ha Hun-Hwan Kim Jeong-Doo Heo Chung-Kil Won Seong-Min Kim Gon-Sup Kim 《Molecules (Basel, Switzerland)》2021,26(9)
Iridin is a natural flavonoid found in Belamcanda chinensis documented for its broad spectrum of biological activities like antioxidant, antitumor, and antiproliferative effects. In the present study, we have investigated the antitumor potential of iridin in AGS gastric cancer cells. Iridin treatment decreases AGS cell growth and promotes G2/M phase cell cycle arrest by attenuating the expression of Cdc25C, CDK1, and Cyclin B1 proteins. Iridin-treatment also triggered apoptotic cell death in AGS cells, which was verified by cleaved Caspase-3 (Cl- Caspase-3) and poly ADP-ribose polymerase (PARP) protein expression. Further apoptotic cell death was confirmed by increased apoptotic cell death fraction shown in allophycocyanin (APC)/Annexin V and propidium iodide staining. Iridin also increased the expression of extrinsic apoptotic pathway proteins like Fas, FasL, and cleaved Caspase-8 in AGS cells. On the contrary, iridin-treated AGS cells did not show variations in proteins related to an intrinsic apoptotic pathway such as Bax and Bcl-xL. Besides, Iridin showed inhibition of PI3K/AKT signaling pathways by downregulation of (p-PI3K, p-AKT) proteins in AGS cells. In conclusion, these data suggest that iridin has anticancer potential by inhibiting PI3K/AKT pathway. It could be a basis for further drug design in gastric cancer treatment. 相似文献
103.
Sanghwa Lee Kyungho Jin Jaekwang Kim Gyunyoung Heo 《Journal of Radioanalytical and Nuclear Chemistry》2017,312(3):495-505
The purpose of this study is to categorize the type of spent nuclear fuels using simulation data-based classification methods. Considering the practical conditions making the full analysis of radioactive nuclides difficult, the classification methods were designed to be robust to noise and missing information. The strength and weakness of three classifiers, linear discriminant analysis, quadratic discriminant analysis and support vector classification were compared, which is developed by the history information such as burnup, enrichment, and cooling type generated from ORIGEN-ARP upon fuel assembly types. Auto-Associative Kernel Regression improved outlier management as a pre-processing technique. 相似文献
104.
In this Letter we study electron interference in nanotube loops. The conductance as a function of the applied voltage is shown to oscillate due to interference between electron beams traversing the loop in two opposite directions, with slightly different velocities. The period of these oscillations with respect to the gate voltage, as well as the temperatures required for the effect to appear, are shown to be much larger than those of the related Fabry-Perot interference. We calculate interaction effects on the period of the oscillations, and show that even though interactions destroy much of the near degeneracy of velocities in the symmetric spin channel, the slow interference effects survive. 相似文献
105.
Development of Imidazoline‐2‐Thiones Based Two‐Photon Fluorescence Probes for Imaging Hypochlorite Generation in a Co‐Culture System
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Dr. Qingling Xu Cheol Ho Heo Gyoungmi Kim Hyo Won Lee Prof. Hwan Myung Kim Prof. Juyoung Yoon 《Angewandte Chemie (International ed. in English)》2015,54(16):4890-4894
We designed and prepared the imidazoline‐2‐thione containing OCl? probes, PIS and NIS , which operate through specific reactions with OCl? that yield corresponding fluorescent imidazolium ions. Importantly, we demonstrated that PIS can be employed to image OCl? generation in macrophages in a co‐culture system. We have also employed two‐photon microscopy and PIS to image OCl? in live cells and tissues, indicating that this probe could have wide biological applications. 相似文献
106.
Multivalent Polymer Nanocomplex Targeting Endosomal Receptor of Immune Cells for Enhanced Antitumor and Systemic Memory Response
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Sun‐Young Kim Min Beom Heo Dr. Geum‐Sook Hwang Youngae Jung Dr. Do Yeol Choi Prof. Dr. Yeong‐Min Park Prof. Dr. Yong Taik Lim 《Angewandte Chemie (International ed. in English)》2015,54(28):8139-8143
We have designed and synthesized linear polymer‐based nanoconjugates and nanocomplexes bearing multivalent immunostimulatory ligands and also demonstrated that the synthetic multivalent nanocomplexes led to an enhanced stimulation of immune cells in vitro and antitumor and systemic immune memory response in vivo. We have developed hyaluronic acid (HA)‐based multivalent nanoconjugates and nanocomplexes for enhanced immunostimulation through the combination of multivalent immune adjuvants with CpG ODNs (as a TLR9 ligand) and cationic poly(L ‐lysine) (PLL; for the enhancement of cellular uptake). The multivalent HA‐CpG nanoconjugate efficiently stimulated the antigen‐presenting cells and the multivalent PLL/HA‐CpG nanocomplex also led to an enhanced cellular uptake as well as continuous stimulation of endosomal TLR9. The mice vaccinated with dendritic cells treated with the multivalent nanocomplex exhibited tumor growth inhibition as well as a strong antitumor memory response. 相似文献
107.
A phase-field model for modeling the diffusional processes in an elastically anisotropic polycrystalline binary solid solution is described. The elastic interactions due to coherency elastic strain are incorporated by solving the mechanical equilibrium equation using an iterative-perturbation scheme taking into account elastic modulus inhomogeneity stemming from different grain orientations. We studied the precipitate interactions among precipitates across a grain boundary and grain boundary segregation–precipitate interactions. It was shown that the local pressure field from one coherent precipitate influences the shape of precipitates in other grains. The local pressure distribution due to primary coherent precipitates near the grain boundary leads to inhomogeneous solute distribution along the grain boundary, resulting in non-uniform distribution of secondary nuclei at the grain boundary. 相似文献
108.
Natural convection heat transfer phenomena on horizontal cylinders were investigated experimentally in order to explore the
applicability of analogy experimental method using the copper electroplating system and to visualize the local heat transfer
depending on the angular position and the diameter of the horizontal cylinder. The diameters of the cylinders are varied from
0.01 to 0.15 m, which correspond to the Rayleigh numbers of 1.73 × 107–5.69 × 1011. The measured mass transfer coefficients show good agreements with the existing heat transfer correlations. The patterns
of copper plated on the aluminum cathodes for various Rayleigh numbers reveal and visualize the local heat transfer depending
on the angular position and show good agreement with the works of Kitamura et al. The hydrogen bubbles produced at higher
applied potential visualize the plumes appeared on top region of the cylinders. 相似文献
109.
Kim SK Li Y Abrol R Heo J Goddard WA 《Journal of chemical information and modeling》2011,51(2):420-433
Subtype 2 serotonin (5-hydroxytryptamine, 5-HT) receptors are major drug targets for schizophrenia, feeding disorders, perception, depression, migraines, hypertension, anxiety, hallucinogens, and gastrointestinal dysfunctions. (1) We report here the predicted structure of 5-HT2B and 5-HT2C receptors bound to highly potent and selective 5-HT2B antagonist PRX-08066 3, (pKi: 30 nM), including the key binding residues [V103 (2.53), L132 (3.29), V190 (4.60), and L347 (6.58)] determining the selectivity of binding to 5-HT2B over 5-HT2A. We also report structures of the endogenous agonist (5-HT) and a HT2B selective antagonist 2 (1-methyl-1-1,6,7,8-tetrahydro-pyrrolo[2,3-g]quinoline-5-carboxylic acid pyridine-3-ylamide). We examine the dynamics for the agonist- and antagonist-bound HT2B receptors in explicit membrane and water finding dramatically different patterns of water migration into the NPxxY motif and the binding site that correlates with the stability of ionic locks in the D(E)RY region. 相似文献
110.
Protein–ligand docking techniques are one of the essential tools for structure‐based drug design. Two major components of a successful docking program are an efficient search method and an accurate scoring function. In this work, a new docking method called LigDockCSA is developed by using a powerful global optimization technique, conformational space annealing (CSA), and a scoring function that combines the AutoDock energy and the piecewise linear potential (PLP) torsion energy. It is shown that the CSA search method can find lower energy binding poses than the Lamarckian genetic algorithm of AutoDock. However, lower‐energy solutions CSA produced with the AutoDock energy were often less native‐like. The loophole in the AutoDock energy was fixed by adding a torsional energy term, and the CSA search on the refined energy function is shown to improve the docking performance. The performance of LigDockCSA was tested on the Astex diverse set which consists of 85 protein–ligand complexes. LigDockCSA finds the best scoring poses within 2 Å root‐mean‐square deviation (RMSD) from the native structures for 84.7% of the test cases, compared to 81.7% for AutoDock and 80.5% for GOLD. The results improve further to 89.4% by incorporating the conformational entropy. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011 相似文献