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991.
Phuong Linh Nguyen Bich Phuong Bui Heesoon Lee Jungsook Cho 《International journal of molecular sciences》2021,22(5)
Novel 1,8-naphthyridine-2-carboxamide derivatives with various substituents (HSR2101-HSR2113) were synthesized and evaluated for their effects on the production of pro-inflammatory mediators and cell migration in lipopolysaccharide (LPS)-treated BV2 microglial cells. Among the tested compounds, HSR2104 exhibited the most potent inhibitory effects on the LPS-stimulated production of inflammatory mediators, including nitric oxide (NO), tumor necrosis factor-α, and interleukin-6. Therefore, this compound was chosen for further investigation. We found that HSR2104 attenuated levels of inducible NO synthase and cyclooxygenase 2 in LPS-treated BV2 cells. In addition, it markedly suppressed LPS-induced cell migration as well as the generation of intracellular reactive oxygen species (ROS). Moreover, HSR2104 abated the LPS-triggered nuclear translocation of nuclear factor-κB (NF-κB) through inhibition of inhibitor kappa Bα phosphorylation. Furthermore, it reduced the expressions of Toll-like receptor 4 (TLR4) and myeloid differentiation factor 88 (MyD88) in LPS-treated BV2 cells. Similar results were observed with TAK242, a specific inhibitor of TLR4, suggesting that TLR4 is an upstream regulator of NF-κB signaling in BV2 cells. Collectively, our findings demonstrate that HSR2104 exhibits anti-inflammatory and anti-migratory activities in LPS-treated BV2 cells via the suppression of ROS and TLR4/MyD88/NF-κB signaling pathway. Based on our observations, HSR2104 may have a beneficial impact on inflammatory responses and microglial cell migration involved in the pathogenesis of various neurodegenerative disorders. 相似文献
992.
NF-κB-inducing kinase (NIK), the essential upstream kinase, which regulates activation of the noncanonical NF-κB pathway, has important roles in regulating immunity and inflammation. In addition, NIK is vital for maintaining cellular health through its control of fundamental cellular processes, including differentiation, growth, and cell survival. As such aberrant expression or regulation of NIK is associated with several disease states. For example, loss of NIK leads to severe immune defects, while the overexpression of NIK is observed in inflammatory diseases, metabolic disorders, and the development and progression of cancer. This review discusses recent studies investigating the therapeutic potential of NIK inhibitors in various diseases. 相似文献
993.
Marieke M. Hoog Antink Lisa Röpke Julia Bartels Christian Soltmann Andreas Kunzmann Kurosch Rezwan Stephen Kroll 《Ceramics International》2018,44(14):16561-16571
The growing demand for stony corals as ornamental aquarium animals requires defined aquacultural breeding strategies. For the sexual propagation of corals, material substrates are needed, that attract larvae and support their settlement and development. In this study, five types of highly porous ceramic materials were developed following the example of coral skeleton. The applicability of these settlement substrates was tested using larvae of the stony coral Pocillopora damicornis. Partial sintering of pressed clay pellets, freeze casting of clay and alumina-mullite based slurries and direct foaming of high alkane phase emulsified suspensions (HAPES) using alumina were employed. By the addition of mm-sized spherical polystyrene beads as sacrificial templates during freeze casting (alumina-mullite), superficial pores in the size of the larvae were created. The inorganic substrates featured open porosities between 35% (pressed clay) and 83% (foamed alumina), pore sizes ranging from nm to mm-scale and pore morphologies dominated by interparticle porosity (pressed), lamellar pores (freeze casting) and cellular pore types (direct foaming). The ceramic substrates were incubated in artificial sea water for 3 months to induce necessary biofilm formation and algae growth. Afterwards, individual substrates were exposed to 5 coral larvae, and their settlement behavior was monitored over 14 days. At the end of this period, all ceramic materials were successfully accepted as settlement substrates, with a mean settlement rate of 46.2%, and no significant differences between the substrate types. On samples with large surface superficial pores, a significantly reduced survival of settled larvae (79%) compared to the other porous materials (93–98%) was determined, suggesting a non-ideal surface topography. While alumina foam samples (HAPES) exhibit the most promising results in terms of settlement and survival of larvae, clay-based substrates provide a more economic solution for the sexual propagation of corals in aquaculture. 相似文献
994.
Tungsten oxide (WO3) nanoplates were synthesized by a 270 W microwave-hydrothermal reaction of Na2WO4·2H2O and citric acid (C6H8O7·H2O) in deionized water. X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED) were used to reveal the synthesis of WO3 complete rectangular nanoplates in the solution of 0.2 g citric acid for 180 min, with O-W-O FTIR stretching modes at 819 and 741 cm−1, and two prominent O-W-O Raman stretching modes at 804 and 713 cm−1. The 2.71 eV indirect energy gap, and 430-460 nm blue emission wavelength range of WO3 complete rectangular nanoplates were determined using UV-visible and photoluminescence (PL) spectrometers. The formation mechanism was also proposed according to the experimental results. 相似文献
995.
Murat Özen Myrjam MertensJan Luyten Frans SnijkersHans D’Hondt Pegie Cool 《Ceramics International》2012,38(1):619-625
In this paper, the amorphous barium titanate precursor was prepared by the peroxo-hydroxide method and post-treated by various drying procedures, such as: room temperature drying, room temperature vacuum drying and vacuum drying at 50 °C. The objective in the latter two treatments was to increase the Ti-O-Ba bonds of the precursor. The post-treated precursors were compared with the untreated (i.e., ‘wet’) precursor. Also, a barium titanate precursor was prepared by an alkoxide route. Afterwards, the precursors were hydrothermally treated at 200 °C in a 10 M NaOH solution. Vacuum drying of the precursor seemingly promoted the formation of Ti-O-Ti bonds in the hydrothermal end-product. The low Ba:Ti ratio (0.66) of the alkoxide-route prepared precursor lead to a multi-phase hydrothermal product with BaTiO3 as the main phase. In contrast, phase pure BaTiO3, i.e. without BaCO3 contamination, was obtained for the precursor which was dried at room temperature. Cube-shaped and highly crystalline BaTiO3 particles were observed by electron microscopy for the hydrothermally treated peroxo-hydroxide-route prepared precursor. 相似文献
996.
《Materials Science & Technology》2013,29(7):1191-1197
AbstractThe influence of B and Si on microstructure and isothermal solidification during transient liquid phase (TLP) bonding of a duplex stainless steel using MBF-30 (Ni–4·5Si–3·2B, wt-%) and MBF-35 (Ni–7·3Si–2·2B, wt-%), was investigated. Based on experimental studies, the formation of Ni3B within the joint centreline is dependent on B content; the morphology of Ni3Si is dominated by Si concentration. There was a deviation between the times for complete isothermal solidification obtained by the experiment and the conventional TLP bonding model. Isothermal solidification of the liquid dependent on different solidification regimes is suggested to be a controlling factor contributing to the change in the rate of isothermal solidification observed using the two filler metals. 相似文献
997.
Ravindran SujithAdhimoolam Bakthavachalam Kousaalya Ravi Kumar 《Ceramics International》2012,38(2):1227-1233
Hafnium alkoxide modified polysilazane was synthesized by the drop-wise addition of hafnium tetra(n-butoxide) to polysilazane. The solid state thermolysis (SST) temperature and the ceramic yield for both the polysilazane and modified polysilazane were determined by performing thermogravimetry. Fourier transform infrared spectroscopy was performed to understand the polymer to ceramic conversion as well as the bonding characteristics of the ceramics. The modified polymer after crosslinking was subjected to SST at 800 °C at a constant heating rate of 5 °C/min for a dwell time of 2 h in atmospheric ambience. From the X-ray diffractograms, the as-thermolysed ceramics were observed to remain X-ray amorphous and on heat-treatment resulted in the crystallization of tetragonal hafnia. However, on heat-treatment at 1500 °C, reverse phase transformation from tetragonal to monoclinic hafnia was observed. Raman spectroscopy and transmission electron microscopy were employed to further understand the phase evolution. The thermal stability and the influence of amorphous matrix on the coarsening of HfO2 were also evaluated. 相似文献
998.
For the potential influence produced by the reinforcement/matrix interphase in particle reinforced metal matrix composites (PMMCs), a unit cell model with transition interphase was proposed. Uniaxial tensile loading was simulated and the stress/strain behavior was predicted. The results show that a transition interphase with both appropriate strength and thickness could affect the failure mode, reduce the stress concentration, and enhance the maximum strain value of the composite. 相似文献
999.
The preparation of defect-free MoS2 nanosheets is a key challenge and essential for practical applications. Herein the dodecanethiol was firstly performed as the antioxidant and surface modifier to produce the defect-free MoS2 by direct ultrasonication of bulk MoS2 in N,N-dimethylformamide. Incorporating defect-free MoS2 into polyethylene obviously improved the properties of PE/MoS2 nanocomposites. For crystallization under quiescent condition, the half crystallization time (t0.5) of nanocomposites containing 0.2 wt% MoS2 was reduced by 87.0% compared to that of neat PE. A 54.3 °C increase in the temperature of maximum weight loss (Tmax) was observed by inclusion of as low as 0.7 wt% defect-free MoS2 nanosheets. In addition, the uniformly distributed MoS2 can considerably improve the mechanical properties of composites. These observations suggest that the robust nature, dramatic barrier action of defect-free MoS2 and the strong nanosheets/matrix interfacial adhesion would be the motivation to improve the performance of the polymeric nanocomposites. 相似文献
1000.
《Ceramics International》2016,42(9):10879-10885
Mesoporous silicon nitride (Si3N4), which is one of the most promising structural materials for applications in high-temperature filtration, was synthesized from the carbothermal reduction and nitridation of a pyrolyzed silica-containing phenol-resorcinol-formaldehyde (PRF) gel. The PRF gel was synthesized by combining sol–gel and polymerization of phenol, resorcinol and formaldehyde using sodium carbonate as a catalyst. Silica was incorporated into the gel by addition of 3-aminopropyl trimethoxysilane (APTMS) as a silica precursor. After aging and being freeze-dried, the silica/PRF composite was pyrolyzed under nitrogen gas to convert it into porous silica/carbon composite. The combination of phenol-formaldehyde (PF) and resorcinol-formaldehyde (RF) gels into PRF gel, allows further enhancement in porosity of the silica/carbon composite via pre-calcination in the range of 400–500 °C, since carbon derived from PF gel and that from RF gel have different thermal stability. The final product obtained after final calcination to remove residual carbon has a surface area as high as 194 m2/g, which is significantly much higher than the conventional Si3N4 granules. Specific surface area of the product is affected by molar ratio of phenol-to-resorcinol, molar ratio of silica-to-carbon, and the pre-calcination temperature. 相似文献