Gas leak detector is simple and inexpensive

Pressure sensor monitors small gas leaks in piping and pressure vessels. A combination of a paper ribbon and adhesive plastic tape is used to cover the area to be monitored and the pressure sensor is placed over a hole in the tape and paper

Optical inspection tool for interior surfaces of fluid lines

Specialized tool enables visual inspection of interior bore surfaces of pipe lines having sharp bends and blind runs. Adjustable, hinged optical head permits viewing of bore surfaces at angles from 0 deg to 115 deg to the principal axis of the sight tube

Rotary-knife stripper facilitates removal of X-ray film from pack

Rotary-knife stripper facilitates removal of X ray film from the daylight pack paper sleeve. The new stripper is rectangular, approximately 4 inches wide, 5 inches high, and 7 inches long

A fluorometric method for the estimation of tryptophan

The various colorimetric methods now employed for the estimation of tryptophan are not specific for tryptophan but give colored products with many compounds containing the indole nucleus, including indole itself. In order to facilitate studies of the enzymatic synthesis of tryptophan from indole and serine by extracts of Neurospora (1), a search for a rapid, quantitative method for the estimation of tryptophan in the presence of indole was undertaken. Tauber (2) reported that tryptophan gives a green fluorescence when treated with 70 to 72 per cent perchloric acid at room temperature. Modification of this procedure has led to a method for the rapid estimation of tryptophan, without preliminary extraction of indole, in hydrolyzed or unhydrolyzed tryptophan-containing materials

Kondo effect in three-dimensional Dirac and Weyl systems

Magnetic impurities in three-dimensional Dirac and Weyl systems are shown to exhibit a fascinatingly diverse range of Kondo physics, with distinctive experimental spectroscopic signatures. When the Fermi level is precisely at the Dirac point, Dirac semimetals are in fact unlikely candidates for a Kondo effect due to the pseudogapped density of states. However, the influence of a nearby quantum critical point leads to the unconventional evolution of Kondo physics for even tiny deviations in the chemical potential. Separating the degenerate Dirac nodes produces a Weyl phase: time-reversal symmetry-breaking precludes Kondo due to an effective impurity magnetic field, but different Kondo variants are accessible in time-reversal invariant Weyl systems.Comment: 4+ pages, 2 figure

Cytochromes and the succinic acid oxidase system of poky strains of Neurospora

Recent investigations in this laboratory (1) have demonstrated that in Neurospora crassa growth characteristics representing at least two stable states are possible with the same constitution of nuclear genes. If a slow growing strain, designated poky, functions in a cross to wild type as the “maternal” or protoperithecial parent, then all progeny from the cross exhibit the poky character. If the cross is made in the reverse, or reciprocal manner, that is, with the wild type strain functioning as a protoperithecial parent, then all progeny are normal in growth rate. During the course of the work on inheritance it was observed that mycelial pads from poky were characterized by a red color reminiscent of that of the heme pigments. Examinations of suspensions and extracts of the mold with a spectroscope yielded the information that poky mycelium contains large quantities of a substance having the absorption spectrum characteristic of cytochrome c, whereas the bands corresponding to cytochromes a and b were not visible. All three of these components were detected easily in the wild type strain. The experimental results presented here provide more precise information on the similarities and differences between these two strains with respect to the cytochrome and the succinic acid oxidase systems. Preliminary observations suggested that poliy in Neurospora is analogous to petite in yeast (2) in which abnormalities in the succinic acid oxidase system have been reported, but this analogy is shown here to be only a partial one

Computer program determines thermal environment and temperature history of lunar orbiting space vehicles

Program computes the thermal environment of a spacecraft in a lunar orbit. The quantities determined include the incident flux /solar and lunar emitted radiation/, total radiation absorbed by a surface, and the resulting surface temperature as a function of time and orbital position

Extraction Methods and an Investigation of Drosophila Lipids

In earlier work (8) we extracted lipids from dried, macerated Drosophila melanogaster with ether, but later, working with larger quantities of undried flies, we found that most of the phospholipids were autolyzed. Kates' studies (2) led him to suggest n-propanol or isopropanol for lipid extraction (isopropanol was his later choice (6, 7)). Attempting to meet the requirements discussed above, we developed a new and relatively simple method of extraction employing n-propanol (9), or chloroformmethanol (2:1). The latter proved to be a more useful solvent. The method will be described in detail below, with results of an examination of Drosophila lipids