Novel synthesis of sulfones from α,α-dibromomethyl aromatics

A novel, high yielding preparation of sulfones from α,α-dibromomethyl aromatics through reaction with a sulfinate salt is reported.     

Determination of 25 elements in the complex oxide mineral zirconolite by analytical electron microscopy

In this paper we describe a technique for the determination of 25 elements in natural zirconolite using energy-dispersive analytical electron microscopy (AEM). The method presented here allows one to quantitatively investigate the chemistry of submicron-scale zones in complex oxide minerals. The effects of electron channeling, thickness variability and variations in detector resolution were minimized by using a controlled set of operating procedures and instrument parameters. To provide a high level of accurayy, k_ATI-factors were determined from standards for most of the 25 elements of interest, including all of the major elements. Each analytical spectrum is reduced to a set of raw peak counts (and errors) using a digital top-hat filter to suppress background followed by multiple least squares fitting of reference spectra. Counting times of 12–15 min per analysis were required to provide suitable counting statistics. Results are presented for zirconolite samples from the contact metamorphic aureole of the Bergell granodiorite intrusion, Switzerland-Italy. A comparison of 43 AEM analyses with 15 analyses obtained by wavelength-dispersive electron probe microanalysis (EPMA) shows that there is excellent agreement between the two data sets in the amounts of individual elements present, chemical trends and overall stoichiometry. An assessment of the combined data set shows that the major substitution mechanisms in the Bergell samples are coupled substitutions involving the M5,6- and M8-sites of the zirconolite structure: ^M8Ca²⁺ + ^M5,6Ti⁴⁺→^M8REE³⁺ + ^M5,6(Al,Fe)³⁺ and ^M8Ca²⁺ + ^M5,6Ti⁴⁺→^M8(Th,U)⁴⁺ + ^M5,6 (Mg,Fe)²⁺.     

Mass spectrometry of N-(Pyrimidin-2-yl)amino acids and their methyl esters

N(Pyrimidin-2-yl)-glycine, -alanine and -phenylalanine (1-3) and their methyl esters (4-6) were investigated using electron impact (EI) mass Spectrometry. The results showed that EI-induced decomposition occurs on the carboxylic group or involves the loss of R₂OH. In contrast to earlier investigations on N-(pyrimidin-4-yl)amino acids, elimination of water (in 1-3) or methanol (in 4-6) was found to be of EI-induced nature. The loss of 'COOH from M⁺ of ester 4 suggests the occurrence of a skeletal rearrangement leading to the isomeric N-methylamino acid.     

Development of an egg-white bioassay for monitoring biotin levels in urine and serum.

This article reports on the development of a simple and cost-effective bioassay for the detection of biotin in urine and serum, based on the very selective binding of avidin and biotin. Avidin was allowed to react without isolating it from egg white. Egg white was treated with the dye HABA, which binds to avidin. Upon subsequent treatment with biotin, HABA is released due to the high affinity of biotin to avidin. The amount of HABA released is proportional to the amount of biotin used.     

Magnetostrictive properties of Ni-ferrite

Initial curve, major and minor magnetostriction hysteresis loops of the NiFe₂O₄ ferrite as the functions of static magnetic field were investgated. Magnetostriction hysteresis loops as the functions of static induction are also presented. The experimental phenomenon of “liftoff” value of the magnetostriction loop is detected.