Latest ArticlesA straightforward coassembly strategy was developed for the preparation of polymeric nanoparticles driving by the intermolecular hydrogen bond between neutral poly(2-methyl-2-oxaozline) (PMeOx), tannic acid (TA) and doxorubicin hydrochloride (Dox). The occurrence of the hydrogen-bonding amongst the different functionalities within the formed nanoparticles was verified by infrared (IR) spectroscopy. Scanning electron microscopy (SEM), dynamic light scattering (DLS), UV-vis absorption and photoluminescent measurements indicated the rapid formation of uniform and water dispersible/stable nanoparticles. The relative poor stability of PMeOx-TA-Dox in fetal bovine serum (FBS) solution enabled the rapid separation of Dox and PMeOx-TA, facilitating the release of Dox and its entrance into cellular nuclei as revealed by confocal laser scanning microscopy (CLSM). The presented strategy may provide an efficient alternative for the construction of multifunctional nanomedicines.
An enantioselective carboxylative cyclization of propargylic alcohols and CO2 was realized under mild conditions, based on a kinetic resolution strategy, which enabled the synthesis of chiral cyclic carbonates and propargylic alcohols with promising yield and enantioselectivity simultaneously.
Targeting bromodomain-containing protein 4 (BRD4) has been proved to be an effective strategy for cancer therapy. To date, numerous BRD4 inhibitors and degraders have been identified, some of which have advanced into clinical trials. In this work, a focused library of new [1, 2, 4]triazolo[1, 5-a]pyrimidine derivatives were discovered to be able to inhibit BRD4. WS-722 inactivated BRD4 (BD1/BD2), BRD2 (BD1/BD2) and BRD3 (BD1/BD2) broadly with the IC50 values less than 5 μmol/L. Besides, WS-722 inhibited growth of THP-1 cells with an IC50 value of 3.86 μmol/L. Like (+)-JQ1, WS-722 inhibited BRD4 in a reversible manner and enhanced protein stability. Docking studies showed that WS-722 occupied the central acetyl-lysine (Kac) binding cavity and formed a hydrogen bond with Asn140. In THP-1 cells, WS-722 showed target engagement to BRD4. Cellular effects of WS-722 on THP-1 cells were also examined, showing that WS-722 could block c-MYC expression, induce G0/G1 phase arrest and p21 up-regulation, and promote differentiation of THP-1 cells. BRD4 inhibition by WS-722 resulted in cell apoptosis and upregulated expression of cleaved caspased-3/7 and PARP in THP-1 cell lines. The [1, 2, 4]triazolo[1, 5-a] pyrimidine is a new template for the development of new BRD4 inhibitors.
Surface chemical properties of supports have an important influence on active sites and their catalytic behavior. Here, we fabricated a series of cobalt-based catalysts supported by carbon layer-coated ordered mesoporous silica (OMS) composites for higher alcohol synthesis (HAS). The carbon layers were derived from different sources and uniformly coated on the porous surface of OMS. Combined with the characterization results of carbonized catalysts, it is demonstrated that the carbon layer-coated supports significantly enhanced the metal dispersion and increased the ratio of Co2+ to Co0 sites, which further increased the CO conversion and alcohols selectivity. Moreover, it is found that the catalytic activity changed in line with the amount of defects and surface oxygenic groups of carbon layers, which resulted from the different carbon sources. The highest space time yield of C2+OH was 27.5 mmol gcat-1 h-1) obtained by the catalyst coated with glucose-derived carbon layer. But the carbon source is not the key factor influencing the distribution of Co-Co2+ dual sites and shows little effect on selectivity in HAS. These results may guide for further design of carbon supported catalysts.
Two-dimensional mesoporous materials combing ultrathin nanosheet morphology with well-defined mesoporous structures, are now emerging and becoming increasingly important for their promising applications in energy storage, electronic devices, electrocatalysts and so on. Here, we synthesized a kind of polypyrrole-based two-dimensional mesoporous materials with uniform pore size, ultrathin thickness and high surface area. Serving for electrochemical NH3 sensor, they exhibited a fast response and high sensitivity. Therefore, our study would promote much interest in design of new materials for gas sensor applications.
Kerogen is known as an important organic part for absorbing and forming shale gas whose absorption function, especially mechanical and tribological properties, has not been fully revealed. Here, we use Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis to reveal the chemical structure of kerogen. We report the first study of the adhesion and friction behavior of kerogen using atomic force microscope (AFM) Nanoman technology. Our finding reveals the friction of kerogen is decreased at higher pressure while is inhibited at increased temperature, and friction decreases logarithmically as the sliding speed increases. The weakened of Al-O linkage at high temperature have great influence on the decrease of friction forces between kerogen and alumina pellet. This finding lays the mechanism for understanding the dynamic adhesion behavior of kerogen in frictions, therefore attracting increasing interests from scientists, researchers, petroleum engineers and investors.
(C6H14N2)[NH4(ClO4)3] is a newly developed porous hybrid inorganic-organic framework material with easy access and excellent detonation performances, however, its thermal properties is still unclear and severely hampered further applications. In this study, thermal behaviors and non-isothermal decomposition reaction kinetics of (C6H14N2)[NH4(ClO4)3] were investigated systematically by the combination of differential scanning calorimetry (DSC) and simultaneous thermal analysis methods. In-situ FTIR spectroscopy technology was applied for investigation of the structure changes of (C6H14N2)[NH4(ClO4)3] and some selected referents for better understanding of interactions between different components during the heating process. Experiment results indicated that the novel molecular perovskite structure renders (C6H14N2)[NH4(ClO4)3] better thermal stability than most of currently used energetic materials. Under high temperatures, the stability of the cage skeleton constructed by NH4+ and ClO4- ionsdetermined the decomposition process rather than organic moiety confined in the skeleton. The simple synthetic method, good detonation performances and excellent thermal properties make (C6H14N2)[NH4(ClO4)3] an ideal candidate for the preparation of advanced explosives and propellants.
A ratiometric fluorescent hybrid nanoprobe CDs-1 for arginine (Arg), exhibiting high sensitivity (the limit of detection, LOD, being 6.5×10-8 mol/L) and excellent selectivity and anti-interference ability, was fabricated through fluorescence resonance energy transfer (FRET) and the electrostatic attraction between positively-charged hemicyanine molecules and negatively-charged carbon dots (CDs). Arg can be quantitatively detected in the concentration range from 6.0×10-5 mol/L to 2.7×10-4 mol/L. Further, due to its ability to target mitochondrion and low cytotoxicity, intracellular Arg was successfully tracked through ratiometric fluorescence imaging.
Constructing a Z-scheme is a significant approach to improve the separation of photogenerated carriers for effective organic pollutant degradation. Herein, a BiVO4/ZnIn2S4 (BZ) Z-scheme composite was successfully synthesized, and applied to photodegrade methyl orange (MO) irradiated by a LED lamp. Anchoring the BiVO4 on the ZnIn2S4 nanoparticles promoted the separation of photogenerated electronholes and broadened the light response range. The detailed characterizations, including surface morphology, elements valence state, and photocurrent performance, demonstrated that the enhanced separation of photogenerated carriers was the pivotal reason for the enhanced photocatalysis reaction. Benefiting from the excellent photocatalytic characteristics, the 5% mass ratio of BZ composite presented the highest MO degradation rate of 0.00997 min-1, which was 1.9 and 10.3 times greater than the virgin ZnIn2S4 and BiVO4, respectively. Furthermore, the BZ hybrid materials indicated a well photo-stability in the four recycling tests.
Ionophore can prominently improve the ion permeability of cell membrane and disrupt cellular ion homeostasis. Most studies regarding ionophore facilitating ion transmembrane transport focus on artificial liquid-liquid interfaces, which have large difference from the actual environment of cell membrane. Here, we construct a supported lipid bilayer on a gold nanoparticles film modified ZnSe prism as an appropriate model of cell membrane to investigate the dynamic of the ion transport facilitated by ionophore using surface enhanced infrared absorption spectroscopy (SEIRAS). We find that the ion transmembrane transport consists of two steps: The ion transmembrane transport starts with the association/disassociation between ion and ionophore at the edge of lipid bilayer; The second step is the transfer of ion-ionophore complex across lipid bilayer. Our results show that the complex transfer across the lipid bilayer is the rate determining step.
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