Determination of the precise composition of the triple sodium uranyl acetates of magnesium, zinc and nickel, and some observations on the use of the first two compounds for the determination of sodium

Three triple sodium uranyl acetates NaM(UO(2))(3)(CH(3) COO)(9) . nH(2)O in which the bivalent metals M were magnesium, zinc and nickel, have been precipitated and the air-dried compounds analysed for uranium by a highly precise method. Despite contrary claims it has been established that the compounds are precise hexahydrates the maximum deviation of n from 6 in any one analysis being 0.1. The precipitation of sodium as the magnesium or zinc compound gives results which depend on the excess of the reagents, and positive errors can be obtained. It is also concluded that, contrary to the usual belief, the magnesium compound is rather less soluble than the zinc one and is therefore somewhat more sensitive for sodium determination.     

Comparison of activation parameters for ionization reactions within zeolites and in aqueous solution

Absolute rate constants for the ionization of chloride from the 2-chloro-1-(4-methoxyphenyl)ethyl radical are measured in aqueous methanol and in alkali-metal cation zeolites as a function of temperature. The absolute rate constants are very fast in the two distinct media. However, the activation parameters are considerably different. In solution, the reaction proceeds with low enthalpies of activation and large, negative entropies of activation, while in zeolites, the reaction is characterized by significantly higher activation enthalpies and large, positive entropies of activation. These differences reveal that the fundamental factors allowing for such rapid reactions are not the same in the two media.     

Bismuth (III) Acetate: A New Catalyst for Preparation of Azlactones via the Erlenmeyer Synthesis

Bismuth(III) acetate catalyzes the synthesis of azlactones from aromatic aldehydes in moderate to good yields via the Erlenmeyer synthesis. The relatively low toxicity and low cost of bismuth(III) acetate make this procedure particularly attractive.     

Microchemical methods in radiochemical analysis : Determination of chemical yields by micro-coulometry

Methods are described for the micro-coulometric determination of several elements using the Reilley and Porterfield method of generating EDTA by electrolysis of its mercuric chelate. The determination is carried out in a volume of about 1 ml of electrolyte and polarized mercury electrodes are used to detect the end-point. 0.025–0.5 μequiv. of many elements can be determined using an ammoniacal electrolyte at pH 10.5 or an acetate buffer at pH 5.5. The method is designed for determining chemical yields of radiochemical procedures using 100–1000-μg amounts of carriers.     

Feedback-controlled electro-kinetic traps for single-molecule spectroscopy

A principal limitation of single-molecule spectroscopy in solution is the diffusion-limited residence time of a given molecule within the detection volume. A common solution to this problem is to immobilize molecules of interest on a passivated glass surface for extending the observation time to obtain reliable data statistics. However, surface tethering of molecules often introduces artifacts, particularly when studying the structural dynamics of biomolecules. To circumvent this limitation, we investigated alternative ways to extend single-molecule observation times in solution without surface immobilization. Among various possibilities, the so-called anti-Brownian electro-kinetic trap (or ABEL trap) seems best suited to achieve this goal. The essential part of that trap is a feedback-controlled electro-kinetic steering of a molecule’s position in reaction to its diffusive Brownian motion which is monitored by fluorescence, thus keeping the molecule within a sub-micron sized detection volume. Fluorescence trace recordings of over thousands of milliseconds duration on individual dye molecules within an ABEL trap have been reported. In this short review, we shall briefly discuss the principle and some results of ABEL trapping of individual molecules with possible extensions to future works.     

The Role of Lignocellulosic Composition and Residual Lipids in Empty Fruit Bunches on the Production of Humic Acids in Submerged Fermentations

The aim of this research was to study the production of humic acids (HA) by Trichoderma reesei from empty fruit bunches (EFBs) of palm oil processing, with a focus on the effects of lignocellulosic content and residual lipids. EFBs from two different soils and palm oil producers were previously characterized about their lignocellulosic composition. Submerged fermentations were inoculated with T. reesei spores and set up with or without residual lipids. The results showed that the soil and the processing for removal of the palm fresh fruits were crucial to EFB quality. Thus, EFBs were classified as type 1 (higher lignocellulosic and fatty acids composition similar to the palm oil and palm kernel oil) and type 2 (lower lignocellulosic content and fatty acids composition similar to palm oil). Despite the different profiles, the fungal growth was similar for both EFB types. HA production was associated with fungal growth, and it was higher without lipids for both EFBs. The highest HA productivity was obtained from type 1 EFB (approximately 90 mg L⁻¹ at 48 h). Therefore, the lignocellulosic composition and the nature of the residual lipids in EFBs play an important role in HA production by submerged fermentation.