Porous V2O5-SnO2/CNTs composites as high performance cathode materials for lithium-ion batteries

Vanadium pentoxide (V₂O₅) exhibits high theoretical capacities when used as a cathode in lithium ion batteries (LIBs), but its application is limited by its structural instability as well as its low lithium and electronic conductivities. A porous composite of V₂O₅-SnO₂/carbon nanotubes (CNTs) was prepared by a hydrothermal method and followed by thermal treatment. The small particles of V₂O₅, their porous structure and the coexistence of SnO₂ and CNTs can all facilitate the diffusion rates of the electrons and lithium ions. Electrochemical impedance spectra indicated higher ionic and electric conductivities, as compared to commercial V₂O₅. The V₂O₅-SnO₂/CNTs composite gave a reversible discharge capacity of 198 mAh·g^?1 at the voltage range of 2.05–4.0 V, measured at a current rate of 200 mA·g^?1, while that of the commercial V₂O₅ was only 88 mAh·g^?1, demonstrating that the porous V₂O₅-SnO₂/CNTs composite is a promising candidate for high-performance lithium secondary batteries.     

Removal of carbonyl sulfide from CO2 stream using AgNO3-modified NaZSM-5

Removal of carbonyl sulfide (COS) from CO₂ stream is significant for the production and utilization of food grade CO₂. This study investigates the adsorption performance of Ag/NaZSM-5 as adsorbent prepared by incipient wetness impregnation for the removal of COS from a CO₂ stream in a fixed-bed adsorption apparatus. Effects of various conditions on the preparation of adsorbent, adsorption and desorption were intensively examined. The results revealed that COS can be removed to below 1×10^?9 from a CO₂ stream (1000 ppm COS/CO₂) using Ag/NaZSM-5 (10 wt% AgNO₃) with an adsorption capacity of 12.86 mg-g^?1. The adsorbent can be fully regenerated using hot air at 450 °C. The adsorption ability remained stable even after eight cycles of regeneration.     

Selective collection and detection of MCF-7 breast cancer cells using aptamer-functionalized magnetic beads and quantum dots based nano-bio-probes

A novel strategy for selective collection and detection of breast cancer cells (MCF-7) based on aptamer–cell interaction was developed. Mucin 1 protein (MUC1) aptamer (Apt1) was covalently conjugated to magnetic beads to capture MCF-7 cell through affinity interaction between Apt1 and MUC1 protein that overexpressed on the surface of MCF-7 cells. Meanwhile, a nano-bio-probe was constructed by coupling of nucleolin aptamer AS1411 (Apt2) to CdTe quantum dots (QDs) which were homogeneously coated on the surfaces of monodispersed silica nanoparticles (SiO₂ NPs). The nano-bio-probe displayed similar optical and electrochemical performances to free CdTe QDs, and remained high affinity to nucleolin overexpressed cells through the interaction between AS1411 and nucleolin protein. Photoluminescence (PL) and square-wave voltammetric (SWV) assays were used to quantitatively detect MCF-7 cells. Improved selectivity was obtained by using these two aptamers together as recognition elements simultaneously, compared to using any single aptamer. Based on the signal amplification of QDs coated silica nanoparticles (QDs/SiO₂), the detection sensitivity was enhanced and a detection limit of 201 and 85 cells mL⁻¹ by PL and SWV method were achieved, respectively. The proposed strategy could be extended to detect other cells, and showed potential applications in cell imaging and drug delivery.     

Copper nanoclusters as peroxidase mimetics and their applications to H2O2 and glucose detection

Copper nanoclusters (Cu NCs) are found to possess intrinsic peroxidase-like activity for the first time. Similar to nature peroxidase, they can catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine by H₂O₂ to produce a nice blue color reaction. Compared with horseradish peroxidase, Cu NCs exhibits higher activity near neutral pH, which is beneficial for biological applications. The increase in absorbance caused by the Cu NCs catalytic reaction allows the detection of H₂O₂ in the range of 10 μM to 1 mM with a detection limit of 10 μM. A colorimetric method for glucose detection was also developed by combining the Cu NCs catalytic reaction and the enzymatic oxidation of glucose with glucose oxidase. Taking into account the advantages of ultra-small size, good stability, and high biocompatibility in aqueous solutions, Cu NCs are expected to have potential applications in biotechnology and clinical diagnosis as enzymatic mimics.     

A new strategy based on cholesterol-functionalized iron oxide magnetic nanoparticles for determination of polycyclic aromatic hydrocarbons by high-performance liquid chromatography with cholesterol column

This study reported for the first time the use of cholesterol-functionalized magnetic nanoparticles (Fe₃O₄@SiO₂@Chol) for the determination of polycyclic aromatic hydrocarbons (PAHs) in traditional Chinese medicine samples (TCMs) by high performance liquid chromatography (HPLC) coupled with fluorescence detection. The method was efficient, environmentally friendly, and fast. The solvent consumption of the proposed column is only half of the conventional column but with higher efficiency. Influencing factors, including sorbent amount, desorption solvent, sample volume and extraction time, were investigated in detail. Under the optimum conditions, good linearity (R² > 0.991) was obtained over the range of 5–400 ng g⁻¹, with limits of detection (LOD) 0.75, 0.50, 1.0, 0.56, 0.60, 0.84 and 0.80 ng g⁻¹ for anthracene, fluoranthene, pyrene, chrysene, benzo[a]anthracene, benzo(b)fluoranthene and benzo(k)fluoranthene, respectively.     

Five New Cycloartane‐Type Triterpenoid Saponins from Nervilia fordii

Five new cycloartane glycosides, nervisides D–H ( 1 – 5 ), were isolated from the AcOEt‐ and H₂O‐soluble portions of the 90% EtOH extract of the aerial part of the plant Nervilia fordii. The structures of the isolated glycosides were elucidated by extensive spectroscopic analysis including HR‐ESI‐MS and NMR data. The isolated nervisides D–H were evaluated for the cytotoxic activity in vitro against human‐tumor cell lines (CNE, Hep‐2 and HepG2) with the MTT method.     

Two New Abietane Diterpenoids from the Roots of Tripterygium wilfordii Hook. f.

Two new abietane‐type diterpenoids, named triptobenzene R ( 1 ) and triptobenzene S ( 2 ), together with three known abietane‐type diterpenoids, triptophenolide ( 3 ), triptonodiol ( 4 ), and triptonoterpene methyl ether ( 5 ), were isolated from the roots of Tripterygium wilfordii Hook . f. Their structures and relative configurations were established by detailed spectral studies, including 1D‐ and 2D‐NMR (HSQC, HMBC, and NOESY), and HR‐ESI‐TOF‐MS, and by comparison with published data. Their absolute configurations were assigned by the CD technique, applied for the first time to abietane diterpenes from Tripterygium wilfordii. Compound 2 is the first abietane‐type norditerpenoid isolated from the genus Tripterygium.     

Prenylated Benzene Metabolites from Melicope pteleifolia

Chemical investigation on the stem and root of Melicope pteleifolia afforded three new prenylated benzene metabolites as racemic mixtures, named pteleifolins A–C ( 1 – 3 , resp.). Their gross structures were elucidated on the basis of spectroscopic analysis, especially 2D‐NMR experiments. An enantiomer resolution of (±)‐ 1 using chiral HPLC was performed, and the absolute configuration of the enantiomers were determined to be (+)‐(S)‐ 1 and (?)‐(R)‐ 1 by means of circular‐dichroism analysis.