Two new compounds from Melodinus suaveolens

Two new compounds, 19-hydroxy-melodinine K (1) and melodiside (2), and 25 known compounds were isolated from leaves and twigs of Melodinus suaveolens. Their structures were elucidated based on 1- and 2-D NMR, FTIR, UV and MS spectroscopic data. 19-hydroxy-melodinine K showed cytotoxic activity against MDA-MB-231 breast, BCG-823 gastric, SW480 colon and Hela cancer cells.     

Theoretical and experimental studies on a compact stretcher with large spectral bandwidth and high transmission efficiency

To ensure safe and effective amplification for the chirped pulse amplification laser facility, many factors such as pulse spectral width, pulse duration, grating parameters and incidence angle parameter are considered carefully in the design of the pulse stretcher. A compact four pass Offner stretcher design is given out. Experiment results show that the stretcher has broad spectral width, large stretching ratio and high transmission efficiency. By comparison, the calculated result of the dispersion effect on the pulse duration is completely consistent with the experiment result.     

Low band‐gap D–A conjugated copolymers based on anthradithiophene and diketopyrrolopyrrole for polymer solar cells and field‐effect transistors

Two conjugated copolymers PADT‐DPP and PADT‐FDPP based on anthradithiophene and diketopyrrolopyrrole, with thiophene and furan as the π‐conjugated bridge, respectively, were successfully synthesized and characterized. The number‐averaged molecular weights of the two polymers are 38.7 and 30.2 kg/mol, respectively. Polymers PADT‐DPP and PADT‐FDPP exhibit broad absorption bands and their optical band gaps are 1.44 and 1.50 eV, respectively. The highest occupied molecular orbital energy level of PADT‐DPP is located at ?5.03 eV while that of PADT‐FDPP is at ?5.16 eV. In field‐effect transistors, PADT‐DPP and PADT‐FDPP displayed hole mobilities of 4.7 × 10^?3 and 2.7 × 10^?3 cm²/(V s), respectively. In polymer solar cells, PADT‐DPP and PADT‐FDPP showed power conversion efficiency (PCE) of 3.44% and 0.29%, respectively. Atomic force microscopy revealed that the poor efficiency of PADT‐FDPP should be related to the large two‐phase separation in its active layer. If 1,8‐diiodooctane (DIO) was used as the solvent additive, the PCE of PADT‐DPP remained almost unchanged due to very limited morphology variation. However, the addition of DIO could remarkably elevate the PCE of PADT‐FDPP to 2.62% because of the greatly improved morphology. Our results suggest that the anthradithiophene as an electron‐donating polycyclic system is useful to construct new D–A alternating copolymers for efficient polymer solar cells. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1652–1661     

Selectivity switch in transformation of CO2 from ethanol to methanol on Cu embedded in the defect carbon

The copper-based catalysts have been generally regarded as high-performance catalysts for CO_2 hydrogenation toward methanol,while the production of ethanol via C–C coupling on the copper-based catalysts is still challenging. Herein, we report a new catalyst where Cu nanoparticles are embedded in the carbon support with abundant defect sites, achieving a high selectivity for ethanol in the CO_2 hydrogenation. The experiments coupled with the theoretical studies show a clear map where carbon defects serve as anchor sites that can stabilize interfacial copper species, and interfacial Cu sites with low coordination numbers can adsorb two C_1 species and later convert them to a C_2 species via a hydrogenation-induced coupling reaction. Further adjacent Cu atoms of interfacial Cu sites can facilitate OH reduction reactions via the Cu–Cu bridge adsorption to assist the formation of ethanol. Especially, those specific active sites easily disappear in the reducing conditions and during the reaction, the major product can transform from ethanol to methanol.     

A Water-Stable Lanthanide Coordination Polymer as Multicenter Platform for Ratiometric Luminescent Sensing Antibiotics

As a hot topic of global concern, the distinguishing and detecting of antibiotic pollution is crucial owing to its adverse effect on ecosystems and human health stemming from excessive use and poor management. Herein, a water-stable lanthanide coordination polymer sensor (Dy-TCPB) with multiple emitting centers is prepared. The versatile Dy-TCPB can conveniently differentiate various antibiotics, and displays a self-calibration luminescent response to nitrofurazone (NFZ) and furazolidone (FZD). Each antibiotic exhibits notable correlation to a unique combination of the two ligand-to-Dy ion emission intensity ratios, enabling two-dimensional fingerprint recognition. Furthermore, the novel self-calibration sensor demonstrates effective recognition of NFZ and FZD with excellent sensitivity and selectivity, and detection limits as low as 0.0476 and 0.0482 μm for NFZ and FZD, respectively. The synthetic approach for the fabrication of a singular coordination polymer exhibiting multiple emissions provides a promising strategy for the development of facile and effective ratiometric sensors.     

3-O-Sulfation of Heparan Sulfate Enhances Tau Interaction and Cellular Uptake

Prion-like transcellular spreading of tau in Alzheimer's Disease (AD) is mediated by tau binding to cell surface heparan sulfate (HS). However, the structural determinants for tau–HS interaction are not well understood. Microarray and SPR assays of structurally defined HS oligosaccharides show that a rare 3-O-sulfation (3-O-S) of HS significantly enhances tau binding. In Hs3st1^−/− (HS 3-O-sulfotransferase-1 knockout) cells, reduced 3-O-S levels of HS diminished both cell surface binding and internalization of tau. In a cell culture, the addition of a 3-O-S HS 12-mer reduced both tau cell surface binding and cellular uptake. NMR titrations mapped 3-O-S binding sites to the microtubule binding repeat 2 (R2) and proline-rich region 2 (PRR2) of tau. Tau is only the seventh protein currently known to recognize HS 3-O-sulfation. Our work demonstrates that this rare 3-O-sulfation enhances tau–HS binding and likely the transcellular spread of tau, providing a novel target for disease-modifying treatment of AD and other tauopathies.     

Weighted estimates for the multilinear maximal function on the upper half‐spaces

For a general dyadic grid, we give a Calderón–Zygmund type decomposition, which is the principle fact about the multilinear maximal function on the upper half‐spaces. Using the decomposition, we study the boundedness of . We obtain a natural extension to the multilinear setting of Muckenhoupt's weak‐type characterization. We also partially obtain characterizations of Muckenhoupt's strong‐type inequalities with one weight. Assuming the reverse Hölder's condition, we get a multilinear analogue of Sawyer's two weight theorem. Moreover, we also get Hytönen–Pérez type weighted estimates.