Densitometric quantitation of neutral lipids on ammonium sulfate impregnated thin-layer chromatograms.

A procedure is described which extends the densitometric quantitation of phospholipids on ammonium sulfate impregnated thin-layer chromatograms by Gluck et al. to include total lipid, free and esterified cholesterol, free fatty acid and triglyceride. Lipids separated on thin-layer plates containing silica gel G impregnated with ammonium sulfate were charred upon heating and absorbance was measured densitometrically. Thus, the necessity of spraying or submersing in a charring agent was eliminated, uniform charring became possible, and quantitation over a wider range of sample sizes than most densitometric procedures was obtained. One linear relationship existed for concentrations of standards over the range of 0.0-3.0 mug and another line from 4.0-50.0 mug. Both accuracy and precision of the method were highly reliable.     

Contemporary carbon-14 in lemongrass oil

Liquid scintillation counting ofp- cymene, derived from lemongrass oil, has provided information on the world-wide increase in C¹⁴ since 1954. By June 1959, the activity in the tropospheric atmosphere and in the rapidly equilibrating biosphere is measured to have increased by 26·8 per cent in the northern hemisphere and 19·7 per cent in the southern hemisphere. The shape of the relationship between activity and time is essentially linear, with two sections of quite different slope.     

Size and Velocity Measurements of Large Drops in Air and in a liquid-liquid two-phase flow by the phase-Doppler technique

Particles comparable in size to or larger than the measurement volume need extra consideration when measured by a phase-Doppler system. The phase of the Doppler burst received when such particles traverse the measurement volume depends not only on the size of the particle but also on its trajectory, since the particle is not uniformly illuminated. This paper presents a strategy for securing correct measurements even under such conditions, taking advantage of the three-detector receiving optics of the Dantec Particle Dynamics Analyzer. The effectiveness of the approach is demonstrated for sizing drops in liquid-gas and liquid-liquid two-phase flows: water drops in air, water drops in FC72 and FC72 drops in water. The combination of water and FC72 is also of interest because the relative refractive index is close to unity. Measurements of drops size were made on a monodisperse stream of drops about 2 mm in diameter, i.e. substantially larger than the measurement volume, and polydisperse distributions of drops ranging in diameter from below 0.2 mm to about 1 mm.     

Preparation of iodic acid by direct oxidation of iodine with perchloric acid dihydrate

Iodine is quantitatively oxidised to iodic acid by boiling with 70% perchloric acid and the iodic acid is isolated by cooling, filtering off the precipitated crystals, and washing them with concentrated nitric acid. The over-all stoichiometry of the reaction is one molecule of perchloric acid per atom of iodine.     

Determination of the amine content of chitosan by pyrolysis-gas chromatography

Pyrolysis-gas chromatography-mass spectrometry has been applied to the study of N-acetyl-d-glucosamine, chitin and chitosans of varying degrees of deacetylation prepared from chitin. An examination of the pyrograms of samples of chitosan revealed that there is a direct correlation between the amine content and the ratio of the areas of the peaks derived from the glucosamine and N-acety-d-glucosamine moieties.     

An optoelectronic recirculating sorter based on CMOS/vertical cavity surface emitting laser smart pixel arrays; architecture and system demonstration

The architecture of an optoelectronic recirculating sorter based on the hybrid integration of CMOS logic circuitry, silicon detector/receivers and vertical cavity surface emitting lasers is presented along with the demonstration of the system.