Interface Engineering in Two‐Dimensional Heterostructures: Towards an Advanced Catalyst for Ullmann Couplings

The design of advanced catalysts for organic reactions is of profound significance. During such processes, electrophilicity and nucleophilicity play vital roles in the activation of chemical bonds and ultimately speed up organic reactions. Herein, we demonstrate a new way to regulate the electro‐ and nucleophilicity of catalysts for organic transformations. Interface engineering in two‐dimensional heteronanostructures triggered electron transfer across the interface. The catalyst was thus rendered more electropositive, which led to superior performance in Ullmann reactions. In the presence of the engineered 2D Cu₂S/MoS₂ heteronanostructure, the coupling of iodobenzene and para‐chlorophenol gave the desired product in 92 % yield under mild conditions (100 °C). Furthermore, the catalyst exhibited excellent stability as well as high recyclability with a yield of 89 % after five cycles. We propose that interface engineering could be widely employed for the development of new catalysts for organic reactions.     

Anti‐Inflammatory Activity of a Novel Acetylene Isolated from the Roots of Angelica tenuissima Nakai

Three polyacetylenes, one novel and two known, were isolated from the root of Angelica tenuissima. Using ¹H‐ and ¹³C‐NMR, COSY, HMBC, and HMQC, their structures were found to be (3R,8S)‐heptadeca‐1‐en‐4,6‐diyne‐3,8‐diol ( 1 ), falcarindiol ( 2 ), and oplopandiol ( 3 ). Absolute configurations of compound 1 were established using Mosher's esterification. In addition, the polyacetylenes ( 1 – 3 ) were evaluated for their anti‐inflammatory activity. Compounds 1 and 3 showed potent inhibitory activity against lipopolysaccharide‐induced nitric oxide (NO) production in RAW267.7 macrophage cells with IC₅₀ values of 4.31 and 5.06 μm, respectively. Compound 1 strongly inhibited inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)‐2 in a concentration‐dependent manner.     

A new flavonol glycoside from the florets of Carthamus tinctorius L.

One new flavonol glycoside, 6-hydroxykaempferol-3-O-β-D-glucoside-7-O-β-D-glucuronide (1), together with eight known flavonoids and three known quinochalcones, was isolated from the florets of Carthamus tinctorius L. Their structures were determined by extensive spectroscopic analyses. Their cardioprotective effects against H₂O₂-induced apoptosis in H9c2 cells were also evaluated; compounds 1, 2, 4–5, 7–10 and 12 provided significant protective effects on H₂O₂-induced H9c2 cells at the concentration of 25 μg/mL.     

Sensitive and Selective Determination of 2,4,6-Trichlorophenol Using a Molecularly Imprinted Polymer Based on Zinc Oxide Quantum Dots

Novel core-shell molecularly imprinted polymers were prepared based on zinc oxide quantum dots for the determination of 2,4,6-trichlorophenol by fluorescence. Principally, ZnO quantum dots and 2,4,6-trichlorophenol were chosen as the core substrate and the template molecule, respectively. The specific recognition sites for 2,4,6-trichlorophenol were obtained during the polymerization process in presence of 3-aminopropyltriethoxysilane and tetraethylorthosilicate. Molecularly imprinted ZnO quantum dots were characterized by transmission electron microscopy and Fourier transform infrared spectroscopy and the optical properties were evaluated by spectrofluorometry. Under the optimal conditions, molecularly imprinted ZnO quantum dots were successfully applied to the sensitive determination and selective recognition of 2,4,6-trichlorophenol in water. A linear relationship was obtained to cover the concentration range of 0–160?µmol?L^?1 with a correlation coefficient of 0.9931 calculated by the Stern–Volmer equation. The products were used for the determination of 2,4,6-trichlorophenol in the water from local rural areas and the results strongly supported that the molecularly imprinted ZnO quantum dots were suitable for the determination of 2,4,6-trichlorophenol in real examples.     

CDK5-dependent inhibitory phosphorylation of Drp1 during neuronal maturation

Mitochondrial functions are essential for the survival and function of neurons. Recently, it has been demonstrated that mitochondrial functions are highly associated with mitochondrial morphology, which is dynamically changed by the balance between fusion and fission. Mitochondrial morphology is primarily controlled by the activation of dynamin-related proteins including dynamin-related protein 1 (Drp1), which promotes mitochondrial fission. Drp1 activity is regulated by several post-translational modifications, thereby modifying mitochondrial morphology. Here, we found that phosphorylation of Drp1 at serine 616 (S616) is mediated by cyclin-dependent kinase 5 (CDK5) in post-mitotic rat neurons. Perturbation of CDK5 activity modified the level of Drp1^S616 phosphorylation and mitochondrial morphology in neurons. In addition, phosphorylated Drp1^S616 preferentially localized as a cytosolic monomer compared with total Drp1. Furthermore, roscovitine, a chemical inhibitor of CDKs, increased oligomerization and mitochondrial translocation of Drp1, suggesting that CDK5-dependent phosphorylation of Drp1 serves to reduce Drp1''s fission-promoting activity. Taken together, we propose that CDK5 has a significant role in the regulation of mitochondrial morphology via inhibitory phosphorylation of Drp1^S616 in post-mitotic neurons.     

Annulation reaction of methyl 2-(benzo[b][1,4]thiazin-3-ylidene)acetate with β-nitrostyrenes and 3-nitrochromenes

The acid catalyzed domino reaction of β-nitrostyrenes with methyl 2-(benzo[b][1,4]thiazin-3-ylidene)acetate, which were previously prepared from the cyclization of 2-aminobenzenethiol and methyl 4-chloroacetoacetate, resulted in 2-arylbenzo[b]pyrrolo[1,2-d][1,4]thiazine-3-carboxylates in high yields. Under same reaction conditions, the similar reaction with 3-nitrochromenes afforded corresponding benzo[b]chromeno[4′,3':4,5]pyrrolo[1,2-d][1,4]thiazine derivatives in good yields.     

Heterogeneous liquid phase oxidation of ethylbenzene to acetophenone with graphene carbon-based catalyst

The series of graphene materials and N-doped graphene materials were successfully synthesized and improved by high-temperature treatment with trace iron oxide. XRD, Raman, FT-IR, TEM and XPS were employed for these catalysts. The catalytic performance of these catalysts was investigated in the selective oxidation of ethylbenzene with tert-butyl hydroperoxide as oxidant. The impacts of temperature, mass of catalysts, reaction time and oxidants on the selective oxidation of ethylbenzene were also investigated. The N-doped graphene materials exhibit greatly remarkable catalytic performance than others. The conversion of ethylbenzene is more than 90% and the selectivity of acetophenone is more than 95% at 353 K. Graphene can be used as catalyst owing to its unique structures and chemical properties. The characterization tests show that the doping of N atoms can create more defects and more active sites in the N-doped graphene materials which could greatly improve the catalytic performance. Furthermore, such cost-effective graphene-based catalysts possess good stability and could be reused at least five times without remarkable loss of the catalytic activity.     

Screening of <Emphasis Type="Italic">Isochrysis</Emphasis> Strains and Utilization of a Two-Stage Outdoor Cultivation Strategy for Algal Biomass and Lipid Production

Isochrysis is a genus of marine algae without cell wall and capable of accumulating lipids. In this study, the lipid production potential of Isochrysis was assessed by comparing 15 Isochrysis strains with respect to their growth rate, lipid production, and fatty acid profiles. Three best strains were selected (lipid productivity, 103.0~121.7 mg L^?1 day^?1) and their lipid-producing capacities were further examined under different controlled parameters, e.g., growth phase, medium nutrient, and light intensity in laboratory cultures. Furthermore, the three Isochrysis strains were monitored in outdoor panel photobioreactors with various initial cell densities and optical paths, and the strain CS177 demonstrated the superior potential for outdoor cultivation. A two-stage semi-continuous strategy for CS177 was subsequently developed, where high productivities of biomass (1.1 g L^?1 day^?1) and lipid (0.35 g L^?1 day^?1) were achieved. This is a comprehensive study to evaluate the lipid-producing capability of Isochrysis strains under both indoor and outdoor conditions. Results of the present work lay a solid foundation for the physiological and biochemical responses of Isochrysis to various conditions, shedding light on the future utilization of this cell wall-lacking marine alga for biofuel production.     

Phenolic resin as a carbon source for the synthesis of monometallic Mo and bimetallic CoMo carbides via carbothermal reduction route

It was the first time that phenolic resin (PR) was used as a carbon source for the synthesis of nanostructured monometallic Mo and bimetallic CoMo carbides via carbothermal reduction route. The results showed that phase-pure β-Mo₂C can be formed under an Ar atmosphere at 900°C or a H₂ atmosphere above 700°C. However, almost pure CoMo carbides (Co₃Mo₃C and Co₆Mo₆C) can be obtained only under a H₂ atmosphere at a low temperature of 630°C for 24 and 48 h, respectively. The role of PR in the preparation process has been investigated and a detailed formation mechanism was proposed based on the experimental results.     

Preparation and characterization of a novel pH-sensitive ion exchange resin

Methylacrylic acid/styrene cross-linked with divinylbenzene is a novel pH-sensitive ion exchange resin. Microspheres of this resin were characterized by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The microspheres showed a pulsatile swelling behavior when the pH of the media changed. The pH-sensitive microspheres were loaded with salbutamol sulfate and the drug-release characteristics were studied under both simulated gastric and intestinal pH conditions. The results obtained showed that the drug release also depended on the pH of the release media.