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101.
Hye Jin Kim Xiao-Jun Li Dong-Cheol Kim Tai Kyoung Kim Jae Hak Sohn Haeun Kwon Dongho Lee Youn-Chul Kim Joung Han Yim Hyuncheol Oh 《Molecules (Basel, Switzerland)》2021,26(18)
Chemical investigation of the Antarctic lichen-derived fungal strain Acremonium sp. SF-7394 yielded a new amphilectane-type diterpene, acrepseudoterin (1), and a new acorane-type sesquiterpene glycoside, isocordycepoloside A (2). In addition, three known fungal metabolites, (−)-ternatin (3), [D-Leu]-ternatin (4), and pseurotin A (5), were isolated from the EtOAc extract of the fungal strain. Their structures were mainly elucidated by analyzing their NMR and MS data. The absolute configuration of 1 was proposed by electronic circular dichroism calculations, and the absolute configuration of the sugar unit in 2 was determined by a chemical method. The inhibitory effects of the isolated compounds on protein tyrosine phosphatase 1B (PTP1B) were evaluated by enzymatic assays; results indicated that acrepseudoterin (1) and [D-Leu]-ternatin (4) dose-dependently inhibited the enzyme activity with IC50 values of 22.8 ± 1.1 μM and 14.8 ± 0.3 μM, respectively. Moreover, compound 1 was identified as a competitive inhibitor of PTP1B. 相似文献
102.
A series of calix[4]arene-based chromogenic sensors bearing the 9,10-anthraquinone moiety have been synthesized and examined for their abilities to recognize various cations such as Li+, Na+, K+, Rb+, Cs+, Ag+, Cd2+, Mg2+, Ca2+, Sr2+, Ba2+, Zn2+, Hg2+, Pb2+, Co2+, and Cu2+ by UV-vis spectroscopy. In acetonitrile, the presence of Cu2+ induces the formation of the 1:1 ligand/metal complex, which exhibits a new absorption band centered at 450 nm, and leads to an obvious color change from yellow to red. 相似文献
103.
Fluorescent coumarinyldithiane as a selective chemodosimeter for mercury(II) ion in aqueous solution
A coumarin-based dithiane (1) was synthesized for the selective detection of Hg2+ with respect to dual chromo- and fluorogenic changing events in an aqueous solution by the mercury-promoted transformation of a dithiane group into an aldehyde functional unit. The Hg2+-selective response of the chemodosimeter was clearly observed in aqueous buffer as well as in human blood plasma medium. 相似文献
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Hee Gyung Kang Hyun Kyung Lee Yo Han Ahn Je-Gun Joung Jaeyong Nam Nayoung K D Kim Jung Min Ko Min Hyun Cho Jae Il Shin Joon Kim Hye Won Park Young Seo Park Il-Soo Ha Woo Yeong Chung Dae-Yeol Lee Su Young Kim Woong Yang Park Hae Il Cheong 《Experimental & molecular medicine》2016,48(8):e251
Nephronophthisis-related ciliopathy (NPHP-RC) is a common genetic cause of end-stage renal failure during childhood and adolescence and exhibits an autosomal recessive pattern of inheritance. Genetic diagnosis is quite limited owing to genetic heterogeneity in NPHP-RC. We designed a novel approach involving the step-wise screening of Sanger sequencing and targeted exome sequencing for the genetic diagnosis of 55 patients with NPHP-RC. First, five NPHP-RC genes were analyzed by Sanger sequencing in phenotypically classified patients. Known pathogenic mutations were identified in 12 patients (21.8%); homozygous deletions of NPHP1 in 4 juvenile nephronophthisis patients, IQCB1/NPHP5 mutations in 3 Senior–Løken syndrome patients, a CEP290/NPHP6 mutation in 1 Joubert syndrome patient, and TMEM67/MKS3 mutations in 4 Joubert syndrome patients with liver involvement. In the remaining undiagnosed patients, we applied targeted exome sequencing of 34 ciliopathy-related genes to detect known pathogenic mutations in 7 (16.3%) of 43 patients. Another 18 likely damaging heterozygous variants were identified in 13 NPHP-RC genes in 18 patients. In this study, we report a variety of pathogenic and candidate mutations identified in 55 patients with NPHP-RC in Korea using a step-wise application of two genetic tests. These results support the clinical utility of targeted exome sequencing to resolve the issue of allelic and genetic heterogeneity in NPHP-RC. 相似文献
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A direct numerical simulation of low Reynolds number turbulent flows in an open‐channel with sidewalls is presented. Mean flow and turbulence structures are described and compared with both simulated and measured data available from the literature. The simulation results show that secondary flows are generated near the walls and free surface. In particular, at the upper corner of the channel, a small vortex called inner secondary flows is simulated. The results show that the inner secondary flows, counter‐rotating to outer secondary flows away from the sidewall, increase the shear velocity near the free surface. The secondary flows observed in turbulent open‐channel flows are related to the production of Reynolds shear stress. A quadrant analysis shows that sweeps and ejections are dominant in the regions where secondary flows rush in toward the wall and eject from the wall, respectively. A conditional quadrant analysis also reveals that the production of Reynolds shear stress and the secondary flow patterns are determined by the directional tendency of the dominant coherent structures. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
110.
Joung Sook Hong Yong Kyung Kim Kyung Hyun Ahn Seung Jong Lee Chongyoup Kim 《Rheologica Acta》2007,46(4):469-478
We investigated the effect of organically modified nanoclay (organoclay) on immiscible polymer blends [polybutylene terephthalate
(PBT)/polyethylene (PE)] with a special focus on the role of clay as a compatibilizer. When organoclay (Nanofil 919; Sud-Chemie,
Inc.) is added to the blend, the clay first locates at the interface and then selectively locates in the PBT phase due to
its affinity with PBT. This results in effective size reduction and narrowed size distribution of the dispersed phase. However,
with a small amount of organoclay, it is observed that the clay locates at the interface regardless of its affinity for a
specific component to minimize the chemical potential. The interfacial tension change of the blend with the addition of organoclay
was quantitatively predicted from extensional force measurement. When the blend is subjected to an extension, the interfacial
tension functions as a resistance against drop deformation. When we added organoclay to the blend, the extensional force was
significantly reduced, which means that the contribution of the interfacial tension to the total force is reduced. For a 10/90
PBT/PE blend, the interfacial tension was reduced from 5.76 to 0.14 cN m−1 when 1 wt% of organoclay was added. This interfacial tension reduction arises from the localization of the organoclay at
the interface and its nonhomogeneous distribution along the interface, suppressing the coalescence between the droplets, which
is a role of a compatibilizer. Conclusively, the immiscible polymer blends can be compatibilized with organoclay. The organoclay
changes the blend morphology by interfacial tension reduction due to the localization of the organoclay at the interface and
by the viscosity ratio change due to the selective localization by its affinity to a specific component in the blend. 相似文献