Determination of Indole-3-acetic Acid in Douglas Fir Using a Deuterated Analog and Selected Ion Monitoring: Comparison of Microquantities in Seedling and Adult Tree.

Indole-3-acetic acid (IAA) content in shoot tips of Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) trees and seedlings was determined by combined gas chromatography-mass spectrometry using a deuterated analog (d(2)-IAA) as an internal standard and the technique of selected ion monitoring. Ratios of the peak heights of the deuterated analog internal standard to endogenous IAA revealed a slightly higher content of IAA in seedlings compared with the shoot tips collected in June.

Ventilatory responses to threshold loaded respiration in man.

In postoperative patients one frequently observes respiratory difficulty in excess of what is indicated by physical alterations in respiratory mechanics. This would suggest that some patients lack normal compensatory mechanisms which respond to mechanical changes in the lung. It is entirely possible that inadequacy of compensatory mechanisms is present before surgery and predisposes patients to respiratory distress.

Microwave-induced plasma coupled to a tantalum-strip vaporization assembly for trace element analysis.

This report describes a tantalum-strip assembly coupled to a microwave-induced plasma. Detection limits obtained for several elements by using the apparatus are given. A procedure using bomb decomposition and chelate extraction in conjunction with the tantalum-strip assembly/microwave-induced plasma system for the determination of trace elements in samples with complex matrices is also described.

A preliminary study on the effect of time on apparent lead content of evaporated milk as determined by non-flame atomic-absorption spectrometry.

Analysis of several brands of canned evaporated milk at various times after opening showed increases in the lead content upon standing. Initially all samples had a lead content within the range 0.1-0.

3-methyl-2-oxazolidone as a solvent for acid-base titrations.

3-Methyl-2-oxazolidone has been evaluated as a solvent for the titration of various weak carboxylic acids and phenols. Its high dielectric constant and wide liquid range contribute to its outstanding solvent properties. Tetrabutylammonium hydroxide was the titrant.

Sulpholane as a solvent for titration of barbiturates and sulpha drugs.

Sulpholane (tetramethylenesulphone) has been used as the medium for non-aqueous potentiometric titration of barbiturates and sulpha drugs with tetrabutylammonium hydroxide. Recoveries for 0.1-0.

Proliferation of cells in the central cylinder of the reduced mutant in lanceolate tomato.

When the reduced phenotype in homozygous lanceolate tomato is cultured on a sterile nutrient medium, there is a considerable amount of cell division within the central cylinder. Such proliferation may occur in response to a stimulus furnished to the shoot by the root.