Latest ArticlesThe synthesis of α-ZrP with a range of crystallinity is of high importance due to the different requirements in various applications. Nanosized crystalline α-ZrP is typically obtained by refluxing amorphous ZrP in concentrated H3PO4 solutions. Microcrystalline α-ZrP are obtained by direct precipitation in the presence of either HF or oxalic acid which are used as complexing agents for zirconium. These larger crystals are useful as ion-exchangers in column-type applications as the back pressure can be significantly reduced. A novel minimalistic synthesis that is green, simple and fast is highlighted in this review. Both nano-sized and micro-sized α-ZrP can be prepared via this protocol to meet many potential applications. Applications of α-ZrP in ion-exchange, catalysis, lubricants, intercalation hosts, polymer fillers and fire retardants are discussed.
An efficient water-based bismuth-mediated addition reaction of carbonyl compound with cyclic allylic halide was developed. The reactions proceeded smoothly in aqueous DMF in the presence of ammonium iodide to afford the corresponding syn-homoallylic alcohols in moderate to good yields with excellent diastereoselectivities (>99:1 syn:anti). Reversal of product diastereoselectivity was observed when heteroaryl aldehyde possessing an adjacent chelating nitrogen atom was employed as substrate.
Sulfamethazine (SMZ) is an important sulfonamide antibiotic. Although the concentration in the environment is small, it is harmful. The drug residues can be transferred, transformed or accumulated, affecting the growth of animals and plants. In this study, the integrated fixed-film activated sludge membrane bioreactor (IFAS-MBR) were constructed to investigate the performance and degradation mechanism of SMZ. The addition of SMZ had a significant impact on the removal of the chemical oxygen demand (COD) and ammonia nitrogen (NH4+-N). The optimal operating conditions were hydraulic retention time (HRT) at 10 h and solid retention time (SRT) at 80 d, respectively. On this basis, the effects of different SMZ concentrations on nutrient removal, degradation, and sludge characteristics were compared. The removal efficiency of SMZ increased with the increase of SMZ concentration. The maximum removal rate was as high as 87%. The SMZ dosage also had an obvious effect on sludge characteristics. As the SMZ concentration increased, the extracellular polymer substances (EPS) concentration and the membrane resistance both decreased, which were beneficial for the reduction of membrane fouling. Finally, seven kinds of SMZ biodegradation intermediates were identified, and the possible degradation pathways were speculated. The microbial community results showed that the microbial diversity and richness in the reactor decreased after adding SMZ to the influent. The relative abundance of Bacteroidetes, Actinobacteria, Saccharibacteria and Nitrospirae increased at the phylum level. Sphingobacteria and Betaproteobacteria became dominant species at the class level. The relative abundance of norankp-Saccharibacteria and Nitrospirae increased significantly, and norank-p-Saccharibacteria may be the dominant bacteria for SMZ degradation.
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.
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.
Seven 2, 6-disubstituted N-(2-phenoxy)ethyl imidazo[1, 2-a]pyridine-3-carboxamide series containing various amine moieties were designed and synthesized as new anti-TB agents. Many of them show excellent in vitro activity against both drug-sensitive MTB strain H37Rv and two MDR-MTB clinical isolates (MIC: < 0.002-0.030 μg/mL). Compounds 2f, 5e and 5g display acceptable safety and pharmacokinetic profiles, opening a new direction for further development.
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.
A selective ring-opening [3+2] cyclization reaction of benzo[d]isoxazoles with 2-bromo-propanamides has been developed. The azaoxyallyl cation intermediates are employed as C~O 3-atom synthon to build oxa-heterocycles via the selectivity of suitable cyclization partners. This transformation provides rapid access to highly functionalized 2-hydroxyaryl-oxazolines under mild conditions and excellent regioselectivity.
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.
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.