Formation of monodisperse poly(1-methacryloxybenzotriazole) particles by radiation-induced dispersion polymerization

Radiation-induced dispersion polymerization of 1-methacryloxybenzotriazole (MABt) in ethyl propionate starts as homogeneous mixture and the resulting polymer precipitates as spherical particles. Formation, size, and shape of polymer particles are strongly dependent on the initial monomer concentration. Three regions can be distinguished: formation of deformed particles at concentrations of 15 w/v-% MABt; formation of spherical particles at concentrations from 18 to 35 w/v-% MABt; no precipitation of polymer at concentrations of 40 w/v-% MABt. The spherical particles at 20 w/v-% MABt had a diameter of 0.54 ± 0.31 m for 3 kGy irradiation and 2.93±0.68 m for 30 kGy. The number distribution of the microspheres shows that the spherical particles with small sizes formed at low irradiation dose (low conversion) disappears with increasing irradiation dose because of multi-coating by newly produced polymer.     

Palladium-catalyzed decarboxylation and decarbonylation under hydrothermal conditions: decarboxylative deuteration

[reaction: see text] Decarboxylation of free carboxylic acid was performed by Pd/C catalyst under hydrothermal water (250 degrees C/4 MPa). Under the hydrothermal conditions of deuterium oxide, decarbonylative deuteration was observed to give fully deuterated hydrocarbons from carboxylic acids or aldehydes.     

Four coumarins from Heracleum yunngningense

Four new coumarins (1-4) were isolated from the roots of Heracleum yunngningense HAND.-MASS. Their structures were established by spectral analyses.     

Studies on extraction of manganese(II) with 1-phenyl-3-methyl-4-acyl-5-pyrazolone

The extraction of Mn(II) with 1-phenyl-3-methyl-4-acyl-5-pyrazolone (HA) in MIBK has been studied. Mn(II) is extracted as MnA(2). The extraction constant for each 4-acyl compound was calculated. The effect of temperature on the extraction of Mn(II) has also been investigated.     

Quantitative in vitro bioassay for recombinant human interleukin-11

A cell culture-based in vitro bioassay was developed to measure the biological activity of recombinant human interleukin-11 (rhIL-11). The bioassay measures induced proliferation of T10 cells, derived from the T1165 murine plasmacytoma line. A colorimetrically detectable formazan product, obtained by cellular reduction of the tetrazolium compound, 4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate (WST-1), was used as an endpoint for response of clone T10 to added rhIL-11. Positions of the samples and the standards in 96-well microplates affected the precision of this bioassay, which was improved by using 2 microplates where serially diluted sample and standard lines were interleaved and their positions were alternated. The coefficient of variation for this bioassay was less than 8%. This method is suitable for quality control of rhIL-11 because of its simplicity, reproducibility, and accuracy.     

Inconsistency in the Stability Constants of Inorganic Polyphosphate Anions Determined by Potentiometry and Spectroscopy

Compared with cyclo -triphosphate anions, cyclo -tri- w -imidotriphosphate anions (Figure 1), cP 3 (NH) 3 3 m , form stable complexes with transition metal ions. Two experimental procedures, potentiometry and spectroscopy, have been applied to determine the stability constants of the complexes with Co 2+ , Ni 2+ , and Cu 2+ ions at 25;C and at I = 0.10 (NaClO 4 ). One-to-one (ML) complex formation has been assumed for the analyses. In the presence of sufficiently high concentration of metal ions, the log g 1 values determined by both methods are consistent with each other, whereas the log g 1 value determined by spectroscopy decreases with the decrease in metal ion concentration. This peculiar phenomenon cannot be explained by the presence of additional complexes, that is, ML 2 or M 2 L. One possible reasoning is agglomeration formation of ligand molecules mediated by countercations in aqueous solution.     

Evaluation of the elastic properties of bulk metallic glasses

The development of bulk metallic glasses as a prominent class of functional and structural materials has attracted considerable interest in the last years. One of the fundamental physical quantities necessary to describe the mechanical properties of the materials is the bulk modulus. In the present article, a simple method to estimate the bulk modulus and its pressure derivative is proposed. It is shown that these quantities can be estimated from the values of the constituent elements and their compositions. Comparison with measured data shows good agreement. The physical background of the method is discussed based on the jellium model of metals.     

Study of VUV emission and γ-ray responses of Nd:BaF2 scintillaotor

Nd³⁺ 1%, 5% and 10% doped BaF₂ single crystals were grown by the micro-pulling down method. Photoluminescence properties, including excitation and emission spectra and luminescence decay were measured under synchrotron radiation excitation at the Superlumi station in HASYLAB at DESY (Hamburg, Germany). The Nd³⁺ related 5d-4f emission lines peaking around 180 nm, 230 nm, and 260 nm, identified as the 5d–⁴I_j, 5d–⁴F_j, and 5d–²G_j transitions, were observed under 140–168 nm excitation. In photoluminescence decay under the 160 nm excitation, the dominant component decay time is about 12, 2.5 and 1.2 ns for Nd³⁺ 1%, 5% and 10% concentration, respectively. The decay time shortening is explained by the concentration quenching effect. Transmittance of Nd1% sample is about 80% for wavelengths above 185 nm. Finally, gamma-ray responses, non-proportionality and energy resolution of Nd1% sample were compared with the undoped BaF₂ scintillator. The light yield of the Nd1%:BaF₂ is about 93% of that of undoped BaF₂. ^©2009 Elsevier Ltd. All rights reserved.