Here, two series of novel ursolic acid-based 1,2,4-triazolo[1,5-a]pyrimidines derivatives were synthesized and screened for their anti-inflammatory activity by evaluating their inhibition effect of using LPS-induced inflammatory response in RAW 264.7 macrophages in vitro; the effects of different concentrations of the compounds on the secretion of nitric oxide (NO) and inflammatory cytokines including TNF-α and IL-6 were evaluated. Their toxicity was also assessed in vitro. Results showed that the most prominent compound 3 could significantly decrease production of the above inflammatory factors. Docking study was performed for the representative compounds 3, UA, and Celecoxib to explain their interaction with cyclooxygenase-2 (COX-2) receptor active site. In vitro enzyme study implied that compound 3 exerted its anti-inflammatory activity through COX-2 inhibition.
This paper proposes an event-based approach to distributed state estimation for nonlinear discrete time-delay systems over sensor networks. First, an event detector is configured at each sensor node to decide when the node should send its sampled measurement output to its neighbors across the communication network. Then, sufficient conditions for the existence of an admissible event-based distributed state estimator are established. A effective algorithm for designing both the distributed state estimator design and the parameters in the event condition could be achieved by solving a set of linear matrix inequalities. Finally, two numerical examples are provided to verify the designed event-based distributed state estimator. 相似文献
Dysidavarones A-D (1-4), four new sesquiterpene quinones possessing the unprecedented "dysidavarane" carbon skeleton, were isolated from the South China Sea sponge Dysidea avara. The structures were established by spectroscopic methods, and the absolute configurations were determined using quantum mechanical calculation of the electronic circular dichroic (ECD) spectrum and exciton chirality CD method. Their cytotoxic activity against four human cancer cell lines and PTP1B inhibitory activity were also evaluated. 相似文献
We have designed and synthesis a new compound of zinc‐porphyrin bearing four pyrene groups (ZnP‐t‐P(py)4) and prepared a new hybrid materials of ZnP‐t‐P(py)4 with graphene oxide (GO) via non‐covalent interactions. The ZnP‐t‐P(py)4, along with four pendant pyrene entities ZnP‐t‐P(py)4, stacking on the (GO) surface due to π‐ π interactions, has been revealed by AFM measurements. FTIR, UV‐vis absorption confirm the non‐covalent functionalization of the GO. Raman spectral measurements revealed the electronic structure of the GO to be intact upon hybrid formation. In this donor‐acceptor nanohybrid, the fluorescence of photoexcited ZnP‐t‐P(py)4 is effectively quenched by a possible electron‐transfer process. The fluorescence and photoelectrical response measurements also showed that this hybrid may act as an efficient photoelectric conversion material for optoelectronic applications. 相似文献
We have designed a 21-residue α-peptide that simultaneously recognizes two decadeoxyoligothymidine (dT(10)) tracts to form triplexes with a peptide-DNA strand ratio of 1:2. The synthetic peptide side chain displays 10 melamine rings, which provide a bifacial thymine-recognition interface along the length of the 21-residue peptide. Recognition is selective for thymine over other nucleobases and drives the formation of ternary peptide·[dT(10)](2) complexes as well as heterodimeric peptide·[dT(10)C(10)T(10)] hairpin structures with triplex stems. 相似文献
Extensive applications of rechargeable lithium-ion batteries (LIBs) to various portable electronic devices and hybrid electric vehicles result in the increasing demand for the development of electrode materials with improved electrochemical performance including high energy, power density, and excellent cyclability, while maintaining low production cost. Here, we present a direct synthesis of ferrite/carbon hybrid nanosheets for high performance lithium-ion battery anodes. Uniform-sized ferrite nanocrystals and carbon materials were synthesized simultaneously through a single heating procedure using metal-oleate complex as the precursors for both ferrite and carbon. 2-D nanostructures were obtained by using sodium sulfate salt powder as a sacrificial template. The 2-D ferrite/carbon nanocomposites exhibited excellent cycling stability and rate performance derived from 2-D nanostructural characteristics. The synthetic procedure is simple, inexpensive, and scalable for mass production, and the highly ordered 2-D structure of these nanocomposites has great potential for many future applications. 相似文献
We study the phantom inflation in little rip cosmology, in which the current acceleration is driven by the field with the parameter of state w<−1, but since w tends to −1 asymptotically, the rip singularity occurs only at infinite time. In this scenario, before the rip singularity is arrived, the universe is in an inflationary regime. We numerically calculate the spectrum of primordial perturbation generated during this period and find that the results may be consistent with observations. This implies that if the reheating happens again, the current acceleration might be just a start of phantom inflation responsible for the upcoming observational universe. 相似文献
Synthesis of silver nanoplates was studied in the modified polyol method, where the nucleation and seed stage occurred in a poly(ethylene glycol) (PEG)-water mixture solution, and the growth stage happened in the PEG environment. The morphological evolution of nanoplates was characterized using UV, SEM, and TEM. Interestingly, plane nanostructures with unusual jagged edges were finally formed in our modified polyol method. Using TEM, we observed the medium state of fusion between two nanoplates, resulting in generating unusual jagged edges. Therefore, a novel two-dimensional oriented attachment occurred in our modified polyol method, which involves smaller nanoplates as the building blocks. Further control experiments showed that the presence of water could break this kinetic preferred reactivity, leading to the formation of nanoparticles. 相似文献