New construction of hybrid and aperiodic ordered PBG cavity

The band gap of a photonic crystal (PhC) cavity intrinsically avoids HOM problems. In this paper, we present a new PBG structure based on the possible advantage of using hybrid structures and aperiodic lattices. This novel hybrid and aperiodically ordered cavity was designed for apparently higher Q-factor (more than 10300) and achieving large accelerating field gradient. The HOMs in the cavity are able to be absorbed efficiently.     

尿素酶固载于纳米二氧化钛多孔膜上的尿素生物传感器

在钛丝基体上沉积一层纳米二氧化钛(TiO2)多孔膜,然后直接将尿素酶吸附在TiO2膜上。基于TiO2膜的pH响应,发展了一种廉价的、易于微型化的pH敏尿素酶传感器。采用石英微天平、红外光谱和紫外可见光谱等手段研究尿素酶在TiO2膜上的物理固载行为。由于纳米TiO2在紫外光下光自洁特性可获得高度洁净的表面,石英微天平研究表明在光自洁后的TiO2膜上尿素酶的吸附具有很好的重复性和稳定性,吸附量为0.22mmol/g,吸附平衡常数k为3.15×105L/mol。采用电位法测定了尿素酶/TiO2复合膜电极的性能及其影响因素,在1.0 mmol/L pH 7~8 PBS,35℃,尿素的响应范围为8.5×10-5~1.5×10-1mol/L,相关系数r为0.993 7,检出限为6×10-5mol/L。     

Aromatic Foldamer Helices as α-Helix Extended Surface Mimetics

Helically folded aromatic oligoamide foldamers have a size and geometrical parameters very distinct from those of α-helices and are not obvious candidates for α-helix mimicry. Nevertheless, they offer multiple sites for attaching side chains. It was found that some arrays of side chains at the surface of an aromatic helix make it possible to mimic extended α-helical surfaces. Synthetic methods were developed to produce quinoline monomers suitably functionalized for solid phase synthesis. A dodecamer was prepared. Its crystal structure validated the initial design and showed helix bundling involving the α-helix-like interface. These results open up new uses of aromatic helices to recognize protein surfaces and to program helix bundling in water.     

Preparation of porous titania–silica microspheres for treatment of radioactive waste

Titania–silica microspheres have been prepared by sol–gel process. Internal gelation route, which use hexamethylenetetramine as the source of ammonia was used for the preparation spherical gel particles. A cationic surfactant, cetrimide was added in the feed broth for introducing meso-porosity in the gel network. Further paraffin oil emulsion was incorporated in the feed broth before gelation for the formation of larger pores in the gel network. The spherical gel particles thus obtained were washed and heat treated under controlled conditions to remove the entrapped surfactant, paraffin oil and other organic compounds resulting in highly porous intact titania–silica microspheres. The material was characterized by surface area, porosity and by SEM photomicrographs. The ion exchange property of this material was studied using the sorption of plutonium on this material from carbonate medium by distribution coefficient studies and ion exchange column loading and elution experiments.     

Densitometric HPTLC Method for Simultaneous Quantification of Sennosides A and B and Gallic Acid in a Pharmaceutical Dosage Form

JPC – Journal of Planar Chromatography – Modern TLC - A densitometric HPTLC method has been established for simultaneous quantification of sennosides A and B and gallic acid in a...     

Synthesis of tetrahydroisoquinoline (TIQ)–oxazoline ligands and their application in enantioselective Henry reactions

A novel family of eleven new tetrahydroisoquinoline (TIQ)–oxazoline intermediates and five corresponding copper(II) catalysts has been developed and applied to the catalytic asymmetric Henry reaction of various aldehydes with nitromethane to provide β-hydroxy nitroalkanes in high conversion (>99%). This paper describes the synthesis of the TIQ compounds from l-dihydroxyphenylalanine (l-DOPA) as the starting material. The chiral ligands were complexed in situ with various transition metals such as Cu, Sc, Co, Zn, Ni and Mn and tested as a chiral catalyst for the Henry reaction. The reaction was optimized in terms of the metal, counter ion, solvent, temperature and over a range of substrates. The corresponding catalyst with copper(II) acetate and 2-propanol as the solvent provides the best enantioselectivities (up to 77% ee) of the corresponding nitroalcohol for 4-chlorobenzaldehyde.     

Synthesis of tetrahydroisoquinoline-diamine ligands and their application in asymmetric transfer hydrogenation

The use of the tetrahydroisoquinoline scaffold is well documented in biologically active compounds. However, reports of the utilisation of tetrahydroisoquinoline compounds in asymmetric catalysis are limited. The synthesis of novel diamine ligands possessing the tetrahydroisoquinoline (tetrahydroisoquinoline) backbone and evaluation of their activity in the asymmetric transfer hydrogenation of acetophenone are presented. The diamine ligands in conjunction with i-PrOH as the hydrogen source and [RhCl₂(Cp1)]₂ as the metal precursor proved to be the most effective of the tetrahydroisoquinoline derivatives for this catalytic system. Water was found to have a profound influence on the enantioselectivity of the reaction. Optimisation of the amount water, i-PrOH and catalytic loading content rendered the best result of 70% enantioselectivity for the (S)-1-phenylethanol isomer product.     

Ultrasound Promoted and Ionic Liquid Catalyzed Cyclocondensation Reaction for the Synthesis of 4(3H)-Quinazolinones

4(3H)‐Quinazolinones were synthesized in high yields by one‐pot three‐component condensation of anthranilic acid, carboxylic acid and aniline in the presence of ionic liquid such as 1‐n‐butyl‐3‐methylimidazolium tetrafluoroborate (BMImBF₄) as catalyst under solvent free and neutral conditions.