Monodisperse rutile microspheres with ultrasmall nanorods on surfaces: Synthesis, characterization, luminescence, and photocatalysis

This work demonstrates the process of building optoelectrically cooperative surface wetting in smart and precise way. The superhydrophobic photosensitive film is constructed with TiO(2) nanotube arrays. Compared with conventional organic dyes, CdS quantum dots (QDs) as sensitizer layer are modified on TiO(2) nanotubes surface to improve photosensitivity of the composited surface in visible light region, which offer the benefit for designing and fabricating solid state hetero-junction devices. ITO glass is introduced as top electrode to apply electrical and optical stimuli and the patterned wetting is instantly obtained with masking light through ITO. The optoelectrically cooperative wettability conversion occurred on superhydrophobic TiO(2) nanotube surface at critical voltage of 12 V, which was decreased by 18 V comparing with only using electric stimulus. This study provides potential applications for TiO(2) nanotube arrays to the associated research of liquid reprography, location-controlled microfluidic device and lab-on-chip.     

Electrochemical oxidation of morin and interaction with DNA

A poly (tetrafluroethylene)-deoxyribonucleate acid (PTFE-DNA) film-modified glassy carbon electrode (GCE) has been fabricated. The electrochemical oxidation behaviors of morin as well as its interaction with DNA have been studied at PTFE-DNA film-modified GCE and bare GCE by electrochemical methods. This modified electrode shows an enhanced effectiveness towards the oxidation of morin. Importantly, as to the interaction between morin and DNA in solution, characteristic parameters such as the binding stoichiometry and association equilibrium constant according to the Hill model for cooperative binding have been determined on the basis of linear sweep voltammetry and chronocoulometry.     

Interaction of the main components from the traditional Chinese drug pair Chaihu-Shaoyao based on rat intestinal absorption

The Chaihu-Shaoyao drug pair (Bupleuri Radix and Paeoniae Radix Alba) which is a traditional Chinese drug pair, has been widely used for anti-inflammatory purposes. Saikosaponin a (SSA), saikosaponin d (SSD) and paeoniflorin are identified as the main components in the pair. The present study focused on the interaction of the main components based on investigating their intestinal absorption using a four-site perfused rat intestinal model in order to clarify the mechanism of the compatibility of Chaihu-Shaoyao. The concentrations of SSA, SSD and paeoniflorin in the intestinal perfusate were determined by LC/MS or UPLC (Ultra Performance Liquid Chromatography) methods, followed by P*(eff) (effective permeability) and 10% ABS (the percent absorption of 10 cm of intestine) calculations. The results showed that all of the three main components displayed very low permeabilities (P*(eff) < 0.4), which implied their poor absorption in the rat intestine. The absorption levels of SSA and SSD were similar in intestine and higher in ileum than those in other intestinal regions in the decreasing order: colon, jejunum and duodenum. However, there is no significant difference in the absorption of paeoniflorin in the four segments (P < 0.05). The P*(eff) values of paeoniflorin exhibited an almost 2.11-fold or 1.90-fold increase in ileum when it was co-administrated with SSA and SSD, as well as 2.42-, 2.18-fold increase in colon, respectively, whereas the absorptions of SSA and SSD were not influenced by paeoniflorin. In conclusion, SSA and SSD could promote the absorption of paeoniflorin. To some extent this might explain the nature of the compatibility mechanisms of composite formulae in TCMs.     

Chiral hierarchical molecular nanostructures on two-dimensional surface by controllable trinary self-assembly

The bottom-up fabrication of surface hierarchical nanostructures is of great importance for the development of molecular nanostructures for chiral molecular recognition and enantioselective catalysis. Herein, we report the construction of a series of 2D chiral hierarchical structures by trinary molecular self-assembly with copper phthalocyanine (CuPc), 2,3,7,8,12,13-hexahexyloxy-truxenone (TrO23), and 1,3,5-tris(10-carboxydecyloxy) benzene (TCDB). A series of flower-like chiral hierarchical molecular architectures with increased generations are formed, and the details of these structures are investigated by high resolution scanning tunneling microscopy (STM). The flower-like hierarchical molecular architectures could be described by a unified configuration in which the lobe of each architecture is composed of a different number of triangular shape building units (TBUs). The off-axis edge-to-edge packing of TBUs confers the organizational chirality of the hierarchical assemblies. On the other hand, the TBUs can tile the surface in a vertex-sharing configuration, resulting in the expansion of chiral unit cells, which thereby further modulate the periodicity of chiral voids in the multilevel hierarchical assemblies. The formation of desired hierarchical structures could be controlled through tuning the molar ratio of each component in liquid phase. The results are significant for the design and fabrication of multicomponent chiral hierarchical molecular nanostructures.     

Effects of vanadium oxide coating on the performance of LiFePO4/C cathode for lithium-ion batteries

Journal of Solid State Electrochemistry - LiFePO4 cathode material is considered as prospective materials for lithium-ion batteries and attracted great interest because of excellent cyclic...     

Devisable POM/Ni Foam Composite: Precisely Control Synthesis toward Enhanced Hydrogen Evolution Reaction at High pH

Polyoxometalates (POMs) are promising catalysts for the electrochemical hydrogen production from water owing to their high intrinsic catalytic activity and chemical tunability. However, poor electrical conductivity and easy detachment of the POMs from the electrode cause significant challenges under operating condition. Herein, a simple one-step hydrothermal method is reported to synthesize a series of Dexter–Silverton POM/Ni foam composites (denoted as Ni M -POM/Ni; M =Co, Zn, Mn), in which the stable linkage between the POM catalysts and the Ni foam electrodes lead to high activity for the hydrogen evolution reaction (HER). Among them, the highest HER performance can be observed in the NiCo-POM/Ni, featuring an overpotential of 64 mV (at 10 mA cm⁻², vs. reversible hydrogen electrode), and a Tafel slope of 75 mV dec⁻¹ in 1.0 m aqueous KOH. Moreover, the NiCo-POM/Ni catalyst showed a high faradaic efficiency ≈97 % for HER. Post-catalytic of NiCo-POM/Ni analyses showed virtually no mechanical or chemical degradation. The findings propose a facile and inexpensive method to design stable and effective POM-based catalysts for HER in alkaline water electrolysis.     

Chemical composition and antimicrobial activities of essential oil from Wedelia urticifolia growing wild in Hunan Province,China

The essential oil obtained from Wedelia urticifolia growing in Hunan Province, China, was analyzed for the first time by capillary GC and GC-MS. A total of 67 constituents, representing 98.68% in essential oil were identified. The major constituents of the oil were: α-pinene (8.85%), limonene (6.38%), carvacrol (6.15%), caryophyllene (6.08%), spathulenol (5.49%), sabinene (5.36%), camphor (4.34%). Antimicrobial potential of oil against bacterial strains (Pseudomonas aeruginosa, Escherichia coli and Bacillus subtilis, and Staphylococcus aureus), yeast strains (Hansenula anomala and Saccharomy cescerevisiae) and molds (Aspergillus niger, Chaetomium globosum, Mucor racemosus, and Monascus anka) was determined by disc diffusion method and broth micro dilution method, respectively. The oil exhibited promising antimicrobial effect as a diameter of zones of inhibition (16.8–24.9 mm). Minimum inhibitory concentration values of oil were ranged 62.5–1000 μg/mL.     

Non‐3d Metal Modulation of a Cobalt Imidazolate Framework for Excellent Electrocatalytic Oxygen Evolution in Neutral Media

Cobalt imidazolate frameworks are classical electrocatalysts for the oxygen evolution reaction (OER) but suffer from the relatively low activity. Here, a non‐3d metal modulation strategy is presented for enhancing the OER activity of cobalt imidazolate frameworks. Two isomorphous frameworks [Co₄(MO₄)(eim)₆] (M=Mo or W, Heim=2‐ethylimidazole) having Co(eim)₃(MO₄) units and high water stabilities were designed and synthesized. In different neutral media, the Mo‐modulated framework coated on a glassy carbon electrode shows the best OER performances (1 mA cm^?2 at an overpotential of 210 mV in CO₂‐saturated 0.5 m KHCO₃ electrolyte and 2/10/22 mA cm^?2 at overpotential of 388/490/570 mV in phosphate buffer solution) among non‐precious metal catalysts and even outperforms RuO₂. Spectroscopic measurements and computational simulations revealed that the non‐3d metals modulate the electronic structure of Co for optimum reactant/product adsorption and tailor the energy of rate‐determining step to a more moderate value.     

Insight into 6π Electrocyclic Reactions of 1,8‐Dioxatetraene

A variety of benzofuranone‐based spiroisochromenes were originally designed and synthesized to gain insight into the oxa‐6π electrocyclic reaction of cis,cis‐1,8‐dioxatetraene for the first time. The stability of the 1,8‐dioxatetraene intermediate is governed by its steric congestion and can be fine‐tuned through modification of the backbone structure, leading to the reactivity differences in the 6π electrocyclic reaction and the emergence of photochromic properties.     

全权、常驻公使与钦差—津约谈判前后的中英职衔对等与邦交平等翻译问题

1858年《天津条约》谈判前后,全权问题和钦差驻京成为中英交涉的核心问题,一度成为谈判延宕的症结所在。英方将全权代表额尔金的职衔Plenipotentiary译作“钦差全权大臣”,同时将Resident Minister译作“钦差”,均引发清廷上下极大抵触。18世纪末19世纪初,英方只能妥协接受马戛尔尼和阿美士德的职衔被译作“贡使”;情势翻转后,先是璞鼎查的职衔在第一次鸦片战争时期译为“钦奉全权大臣”,到第二次鸦片战争时期,额尔金的职衔则更进一步译成“钦差全权大臣”。汉译“钦差全权大臣”使得Plenipotentiary的含义生发了显著变化−经过英方在翻译上的操纵,指向了英文的Plenipotentiary + Imperial Commissioner的叠合。英方如此翻译,表面上看是为争取或表明英中两国谈判代表地位上的对等或平行,反映出英方自马戛尔尼访华始追求邦交平等或均势的意图,实际上却创制了新的身份不对等关系,折射出中英实力此消彼长的现实。历时地看,英方追求词语对等努力虽先后遭到乾隆帝和咸丰帝的抵制,但其成果最终经过不平等条约确定与固化下来,使得刚刚开启的中英外交关系陷入了新的不平等境地。中国在由英国人主导的条约外交体系中,陷入了与英国新不平等地位的尴尬境地。