Monosized cationic nanoparticles prepared by emulsifer-free emulsion polymerization

Monosized poly(styrene/N-[3-(dimethylamino)propyl]methacrylamide/poly(ethylene glycol) ethyl ether methacrylate) [poly(St/PEG-EEM/DMAPM)] cationic nanoparticles were synthesized by emulsifier-free emulsion polymerization conducted in the presence of a cationic initiator, 2,2-azobis(2-methylpropionamidine) dihydrochloride (APDH or V-50). Particle sizes and surface charge densities were measured with a Zeta Sizer. The structure of the terpolymers was determined by Fourier transform IR and ¹H NMR spectroscopies. The amounts of the main monomer (St), cationic comonomer (DMAPM), stabilizer (PEG-EEM), and initiator (APDH), and the water-to-monomer phase ratio were all effective on both the average size and the surface charge of the nanoparicles. The average particle size was in the range 75–400 nm depending on the recipe applied; it decreased on increasing the amount of DMAP or PEG-EEM or the water-to-monomer phase ratio in the feed, while it increased with increasing St or APDH content. These nanoparticles were quite monodisperse with a polydispersity index of 1.008–1.14.     

Hermite Interpolation and Sobolev Orthogonality

In this paper, we study orthogonal polynomials with respect to the bilinear form (f, g) _S = V(f) A V(g) ^T + <u, f ^(N) g ^(N)V(f) =(f(c ₀), f "(c ₀), ..., f ^{(n – 1)} ₀(c ₀), ..., f(c _p ), f "(c _p ), ..., f ^{(n – 1)} _p(c _p )) u is a regular linear functional on the linear space P of real polynomials, c ₀, c ₁, ..., c _p are distinct real numbers, n ₀, n ₁, ..., n _p are positive integer numbers, N=n ₀+n ₁+...+n _p , and A is a N × N real matrix with all its principal submatrices nonsingular. We establish relations with the theory of interpolation and approximation.     

Pinning of quantized vortices in helium drops by dopant atoms and molecules

Using a density functional method, we investigate the properties of liquid 4He droplets doped with atoms (Ne and Xe) and molecules ( SF6 and hydrogen cyanide). We consider the case of droplets having a quantized vortex pinned to the dopant. A liquid-drop formula is proposed that accurately describes the total energy of the complex and allows one to extrapolate the density functional results to large N. For a given impurity, we find that the formation of a dopant+vortex+(4)He(N) complex is energetically favored below a critical size N(cr). Our results support the possibility to observe quantized vortices in helium droplets by means of spectroscopic techniques.     

Preparation of hybrid film with superhydrophobic surfaces based on irregularly structure by emulsion polymerization

A superhydrophobic surface originated from quincunx-shape composite particles was obtained by utilizing the encapsulation and graft of silica particles to control the surface chemistry and morphology of the hybrid film. The composite particles make the surface of film form a composite interface with irregular binary structure to trap air between the substrate surface and the liquid droplets which plays an essential role in obtaining high water contact angle and low water contact angle hysteresis. The water contact angle on the hybrid film is determined to be 154 ± 2° and the contact angle hysteresis is less than 5°. This is expected to be a simple and practical method for preparing self-cleaning hydrophobic surfaces on large area.     

A new alkaloid from Lycoris aurea

A new alkaloid was isolated from the bulbs of Lycoris aurea(L'Herit.) Herb.Its structure was established as 3-o-ethyltazettinol through chemical and spectroscopic studies including 2D NMR.     

Water and fluorinated alcohol mediated/promoted tandem insertion/aerobic oxidation/bisindolylation under metal-free conditions: Easy access to bis(indolyl)methanes

A green tandem reaction, including insertion/aerobic oxidation/bisindolylation, starting from indoles and diazo compounds has been developed. The combination of water and fluorinated alcohol plays dual roles as solvent and promoter in this chemical transformation. Molecular oxygen in the air acts as an oxidant. 3,3′-Bis(indolyl)methanes with quaternary carbon were produced under metal-free conditions. No any catalyst and additive were required. N₂ and water were released as sole by-products. Absence of water and fluorinated alcohol resulted in Wolff rearrangement product.     

Some Observations Concerning Thallium Electrodeless Discharge Tubes

The suitability of thallium halide electrodeless discharge tubes as a radiation source for atomic fluorescence was investigated. Effects of various parameters, affecting the emission intensities, were investigated.     

An enzyme-linked immunometric assay for cortisol based on idiotype-anti-idiotype reactions

Cortisol levels in body fluids are useful for monitoring the function of the pituitary-adrenal axis. Here, we established an “enzyme-linked immunometric assay” (a noncompetitive-type ELISA) for cortisol based on idiotype-anti-idiotype reactions. Six different anti-idiotype monoclonal antibodies that recognized the variable regions of a newly established anti-cortisol antibody were generated using hybridoma technology; these were two β-type and four α-type anti-idiotype antibodies, recognizing the paratope and framework regions, respectively. An immunometric assay was established using a combination of a selected α-type and a selected β-type antibody. The analyte (cortisol) was captured by an excess amount of anti-cortisol antibody immobilized on microplates, and the unoccupied paratope was saturated with the β-type antibody. Hapten-occupied anti-cortisol antibody, with less steric hindrance, was then selectively bound by the α-type antibody, labeled with biotin. The amount of biotin residue on the microplates was colorimetrically monitored using a peroxidase-labeled streptavidin. This assay had an approximately threefold higher sensitivity (detection limit: 90 pg = 248 fmol cortisol) than a competitive ELISA using the same anti-cortisol antibody, as well as a practical specificity for providing reasonable determination of normal urinary cortisol levels.     

The facile synthesis of benzothiazolylideneacetates and 1,4-benzothiazines through a highly controllable oxidation of benzothiazolylacetates

The synthesis of benzothiazolylideneacetates and 1,4-benzothiazine was found to be highly controllable via simple exchange of corresponding oxidants. It turned out that the treatment of benzothiazolylacetates with m-CPBA gave 1,4-benzothiazines via oxidative ring expansion process, and with DDQ gave benzothiazolylideneacetates via dehydrogenation, in good yield, respectively. The structures of both skeletons were confirmed by their X-ray diffractions. A previously reported method for the synthesis of benzothiazolylideneacetates was thus proved to be incorrect.     

Thermally-induced optical bistability with two holding beams

Thermally-induced optical bistability with two holding beams has been experimentally investigated in a metal-dielectric-metal interference mirror. Steady-state responses different from the usual S-shaped curve and with potential interest for composite logic operations are reported.