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991.
Michael A. Beswick Nick Choi Alexander D. Hopkins Yvonne G. Lawson Mary McPartlin Alexander Rothenberger Dietmar Stalke Andrew E. H. Wheatley Dominic S. Wright 《Angewandte Chemie (International ed. in English)》1999,38(20):3053-3055
Thermally unstable crystals of the title compound—the first bismuth phosphide complex to be structurally characterized (see picture)—are obtained by the reaction of [Bi(NMe2)3] with [tBuPHLi] (1:3) in THF/hexane. Berry pseudorotation of the pseudo-trigonal-bipyramidal [{(tBuP)3}2Bi]− ion is prevented for steric reasons. 相似文献
992.
Seyeon Oh Chang Hu Choi Bae-Jin Lee Joung-Hyun Park Kuk-Hui Son Kyunghee Byun 《Molecules (Basel, Switzerland)》2021,26(23)
It is well known that oxidative stress induces muscle atrophy, which decreases with the activation of Nrf2/HO-1. Fermented oyster extracts (FO), rich in γ-aminobutyric acid (GABA) and lactate, have shown antioxidative effects. We evaluated whether FO decreased oxidative stress by upregulating Nrf2/HO-1 and whether it decreased NF-κB, leading to decreased IL-6 and TNF-α. Decreased oxidative stress led to the downregulation of Cbl-b ubiquitin ligase, which increased IGF-1 and decreased FoxO3, atrogin1, and Murf1, and eventually decreased muscle atrophy in dexamethasone (Dexa)-induced muscle atrophy animal model. For four weeks, mice were orally administered with FO, GABA, lactate, or GABA+Lactate, and then Dexa was subcutaneously injected for ten days. During Dexa injection period, FO, GABA, lactate, or GABA+Lactate were also administered, and grip strength test and muscle harvesting were performed on the day of the last Dexa injection. We compared the attenuation effect of FO with GABA, lactate, and GABA+lactate treatment. Nrf2 and HO-1 expressions were increased by Dexa but decreased by FO; SOD activity and glutathione levels were decreased by Dexa but increased by FO; NADPH oxidase activity was increased by Dexa but decreased by FO; NF-κB, IL-6, and TNF-α activities were increased by Dexa were decreased by FO; Cbl-b expression was increased by Dexa but restored by FO; IGF-1 expression was decreased by Dexa but increased by FO; FoxO3, Atrogin-1, and MuRF1 expressions were increased by Dexa but decreased by FO. The gastrocnemius thickness and weight were decreased by Dexa but increased by FO. The cross-sectional area of muscle fiber and grip strength were decreased by Dexa but increased by FO. In conclusion, FO decreased Dexa-induced oxidative stress through the upregulation of Nrf2/HO-1. Decreased oxidative stress led to decreased Cbl-b, FoxO3, atrogin1, and MuRF1, which attenuated muscle atrophy. 相似文献
993.
Miscibility behavior and rheological properties with mechanical spectroscopy study of both poly(3-hydroxybutyrate) (PHB)/poly(ethylene oxide) (PEO) and biodegradable synthetic aliphatic polyester (BDP)/linear low density polyethylene (LLDPE) were investigated. Blends of BDP with LLDPE were immiscible, showing two separate Tg values in all compositions; whereas blends of PHB with PEO were miscible, showing a single Tg in the whole range of compositions. However, the shear viscosities of both synthetic and biosynthetic blend systems decrease with increasing shear rate. When a modified Cole-Cole plot of the blend system is further considered, the logG′-logG” plot shows little sensitivity to a variation in both LLDPE composition for synthetic BDP and PEO composition for biosynthetic PHB. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-co-3HV)) random copolymers were also investigated. 相似文献
994.
Hye Ri Kim Daae Lee Ga Hyeon Lee Seong Kyun Kim Seong Jin Choi Ee Taek Hwang Anoth Maharjan Beom Soo Kim Dongyoung Kim Jong Hoon Joo 《Particle & Particle Systems Characterization》2019,36(9)
To elucidate the origin of antibacterial activity of ZnO nanoparticles, a reactive oxygen species (ROS) mechanism is systematically investigated based on electronic and protonic conductions. While the enhancement of antibacterial activity by an increase in electronic conductivity is marginal, an apparent improvement is observed by in the increase of protonic conductivity in terms of the surface basicity. This study first demonstrates that antibacterial activity can be enhanced by controlling the surface basicity of solid particles. The basicity of ZnO can be modulated by doping alkaline‐earth oxides such as MgO and CaO, and it results in the increase of hydroxyl defects on the surface of solid particles. The basicity shows a strong dependency on mobile OH concentrations. The increase of ROS hydroxyl radicals is confirmed by Mg (ZMO) or Ca‐doping (ZCO), which shows high antibacterial activity, and Ca‐doped ZnO exhibits the highest performance. It is clearly observed that the antibacterial activity is proportional to the basicity, which is controlled by the mobile OH formation. While both electrons and hydroxyl species are required for ROS reactions, it is concluded that the formation of hydroxyl species is a key factor in improving the antibacterial activity in ZnO. 相似文献
995.
Jaeyoung Hwang Seung Heon Lee Myong Yong Choi Kang Yeol Lee 《Current Applied Physics》2019,19(6):762-767
A simple method for synthesizing the BixPdy bimetallic particles is described. The structure, composition distribution and size of synthesized BixPdy bimetallic particles were characterized using a number of analytical techniques. The Bi:Pd atomic ratio (x:y) of the nanoparticles was determined to be approximately 1:3 (Bi24Pd76), 1:1 (Bi54Pd46) and 3:1 (Bi74Pd26). The (111) diffraction peaks within the X-ray diffraction patterns of the bimetallic nanoparticles shifted from 39.9° to 38.5° as the Bi content increased from 0% to 75%. The d-spacings calculated from the 2θ data of (111) planes were 2.33, 2.34, 2.32 and 2.26 nm for nanoparticles with a Bi:Pd atomic ratio of 3:1, 1:1, 1:3 and 0:1 respectively. The crystalline properties of the surface of the BixPdy bimetallic nanoparticles were observed in high-resolution transmission electron microscopy analysis. The d-spacings between the adjacent lattice planes were measured on the surface of BixPdy bimetallic nanoparticles by averaging 10 lattice fringes distance. A regular face-centered cubic lattice was observed throughout the prepared BixPdy bimetallic nanoparticles. The lattice d-spacing of the Bi3Pd1, Bi1Pd1 and Bi1Pd3, bimetallic nanoparticles was approximately 2.34, 2.33 and 2.32 Å, respectively, which can be indexed to the (111) planes. These measurements correspond to the values calculated using the Bragg equation (d = nλ/2sinθ). The catalytic activity of BixPdy bimetallic nanoparticles was determined for the nitro compound reduction and Suzuki-Miyaura coupling reactions under green conditions (in an aqueous solution). Bi1Pd3 nanoparticles were shown to provide the best catalytic performance during both reactions, resulting in a yield of 98% in both cases. 相似文献
996.
997.
Hyun Kyoung Yang G. Seeta Rama Raju Byung Chun Choi Jung Hwan Kim 《Applied Surface Science》2009,255(9):5062-5066
CaTiO3:Pr3+ films were deposited on different substrates such as Al2O3 (0 0 0 1), Si (1 0 0), MgO (1 0 0), and fused silica using pulsed laser deposition method. The crystallinity and surface morphology of these films were investigated by XRD and SEM measurements. The films grown on the different substrates have different crystallinity and morphology. The FWHM of (2 0 0) peak are 0.18, 0.25, 0.28, and 0.30 for Al2O3 (0 0 0 1), Si (1 0 0), MgO (1 0 0), and fused silica, respectively. The grain sizes of phosphors grown on different substrates were estimated by using Scherrer's formula and the maximum crystallite size observed for the thin film grown on Al2O3 (0 0 0 1). The room temperature PL spectra exhibit only the red emission peak at 613 nm radiated from the transition of (1D2 → 3H4) and the maximum PL intensity for the films grown on the Al2O3 (0 0 0 1) is 1.1, 1.4, and 3.7 times higher than that of the CaTiO3:Pr3+ films grown on MgO (1 0 0), Si (1 0 0), and fused Sillica substrates, respectively. The crystallinity, surface morphology and luminescence spectra of thin-film phosphors were highly dependent on substrates. 相似文献
998.
The aim of this study was to measure the shear modulus of the vocal fold in a human hemilarynx, such that the data can be related to direction of applied stress and anatomical context. Dynamic spring rate data were collected using a modified linear skin rheometer using human hemilarynges, and converted to estimated shear modulus via application of a simple shear model. The measurement probe was attached to the epithelial layer of the vocal fold cover using suction. A sinusoidal force of 3g was applied to the epithelium, and the resultant displacement logged at a rate of 1kHz. Force measurement accuracy was 20microg and position measurement accuracy was 4microm. The force was applied in a transverse direction at the midmembranous point between the vocal process and the anterior commissure. The shear modulus of the three female vocal folds ranged from 814 to 1232Pa. The shear modulus of the three male vocal folds ranged from 1021 to 1796Pa. These data demonstrate that it is possible to obtain estimates for the shear modulus of the vocal fold while preserving anatomical context. The modulus values reported here are higher than those reported using parallel plate rheometry. This is to be expected as the tissue is attached to surrounding structures, and is under natural tension. 相似文献
999.
1000.
We examine whether the general type Fock-state wave functions for the harmonic oscillator have some relations with the classical
initial condition. 相似文献