A. Weinreb

Iron, Copper, and Zinc Concentrations in Normal Skin and in Various Nonmalignant and Malignant Lesions

ABSTRACT: The concentrations of zinc (Zn), copper (Cu), and iron (Fe) in the skin have been noninvasively determined in vivo by diagnostic x‐ray spectrometry. The skin of healthy controls was divided into two major groups based upon the distribution of the concentrations of these elements. In the face and upper neck, the following wet weight concentrations were recorded: Fe, 14.2 ± 3.3 ppm; Cu, 1.3 ± 0.3 ppm; and Zn, 6.7 ±1.1 ppm. In the chest, abdomen, arm, axilla, and lower neck, the concentrations of these elements were as follows: Fe, 10.2 ± 2.5 ppm; Cu, 0.8 ± 0.3 ppm; and Zn, 4.5 ± 1.7 ppm. In most lesions of solar dermatitis, solar keratosis, basal and squamous cell carcinomas, variable elevations of Zn and Fe (up to significant levels) were recorded in most of the contralateral, apparently uninvolved skin. In the majority of pigmented nevi and malignant melanomas, the levels of Fe and Zn were elevated. In some of these, the Cu concentration also was increased.

Detection and analysis of metals in the eye by x-ray spectrometry.

A method for the analysis of metallic foreign bodies (and, in particular, for the determination of the concentration of dissolved copper) in the vitreous body of the eye is discussed. The method is based on the x‐ray fluorescence of the foreign metal. The limit of detection of the system for a given dose is thoroughly investigated. Experiments on test animals indicate a natural content of copper in the wall of the eye which is equal for both eyes.Analyses of metallic foreign bodies in the eyes of patients are reported.

Energy Transfer from Solvent to Solute in Organic Solutions under Excitation in the Vacuum Ultraviolet

Solutions of 2,5‐diphenyloxazole (PPO) in benzene, toluene, cyclohexane, and hexane are selectively excited by radiation in the wavelength region 3000–1100 A, and the resulting fluorescence is recorded. It is found that all four solvents transfer excitation energy to the solute in the region in which they strongly absorb. Possible implications of these results for γ and β excitation are considered.

In vivo Measurements of Iron, Copper and Zinc in the Skin of Prurigo nodularis Patients Treated with Thalidomide

The concentration of iron, cooper and zinc in the skin of patients with prurigo nodularis was measured by diagnostic X-ray spectrometry before and after treatment with thalidomide. Before treatment, larger skin lesions were associated with significantly higher zinc levels and higher iron levels than the smaller ones. Upon treatment the zinc and iron content in these lesions decreased towards normal range. Copper values were found to be within the normal range in lesions before and after thalidomide treatment.

Inter‐ and Intramolecular Processes in Organic Solutions under Excitation in the Vacuum Ultraviolet

The efficiency of energy transfer from solvent to solute is investigated as a function of solute concentration and excitation wavelength for solutions of diphenyloxazole in benzene, toluene, cyclohexane, and hexane. The results for benzene and toluene are similar but different from those for cyclohexane and hexane. For the first pair of solvents energy transfer takes place almost exclusively from the first excited level for all wavelengths of excitation; only for higher acceptor concentrations does the direct transfer from higher levels become noticeable. The transfer efficiency from the first excited level depends, however, strongly on the electronic level which has been initially excited. The effect of dilution of the transferring solvent is studied. For cyclohexane and hexane two or more transfer mechanisms or transferring species seem to be significantly involved even for low acceptor concentrations. The quenching effect of carbon tetrachloride and of chloroform is investigated for benzene and toluene...

Influence of Oxygen on the Transfer Efficiency and Fluorescent Yield of Organic Solutions

The quenching action of oxygen on the transfer efficiency and fluorescent yield of organic solutions is investigated in systems in which the transferring solvent is undiluted and in systems in which it is diluted by an inert solvent. It is shown that quenching by oxygen is a process competing with energy transfer from the solvent to the solute, with emission of solute fluorescence, and with self‐quenching of the solute. Experimental evidence for the assumption that transfer of energy takes place by a direct interaction between excited solvent molecules and accepting solute molecules is augmented.

Optical Properties of Polystyrene Films in the Far Ultraviolet

Measurements of the optical properties of solid polystyrene in the wavelength range 1100‐2300 A are reported. The real and imaginary parts of the complex index of refraction were determined from transmission measurements on a series of thin films. The absorption spectrum shows a strong peak at 1925 A plus minor features around 1350 and 2170 A as well as evidence for a second major peak below 1100 A. The measured values of the optical constants were used to calculate the complex dielectric constant and the characteristic electron energy‐loss function. The latter exhibits a maximum at 6.92 eV which appears to arise primarily from collective excitation effects.

On the Excitation Spectrum of Polystyrene in the Vacuum Ultraviolet

The over‐all fluorescence yield of polystyrene has been investigated as a function of excitation wavelength in the region 2850–584 A. Polystyrene dissolved in cyclohexane and solid samples of polystyrene after various modes of treatment (machining, pressure, polishing, etc.) as well as thin films were investigated. In all cases a strong dependence of the quantum yield on excitation wavelength has been found. The behavior of polystyrene in solution is basically different from that of the solid plastic. For the solid two types of behavior have been found, depending on the preparation of the sample. The results indicate the decisive influence of the state of aggregation on the luminescent behavior for excitation of the higher electronic levels.

Effects of Fluorescence and Energy Transfer in Polystyrene under Excitation in the Vacuum Ultraviolet

The emission spectrum of solid polystyrene is investigated as a function of excitation wavelength in the region 2540–1216 A, for various modes of preparation (solid machined disks, films, evaporation layers) and treatment (heating, polishing, etc.). A strong dependence of the spectral distribution on excitation wavelength is observed. Exciting radiation which is more strongly absorbed produces a fluorescence spectrum extending to longer wavelengths. A strong influence of the mode of preparation and treatment of the sample on the fluorescence spectrum is observed. The results are tentatively interpreted as representing the strong influence of the solid‐state structure of the material on intermolecular interactions between segmers.The fluorescent quantum yield of solid solutions of diphenyloxazole and of anthracene in polystyrene is investigated as a function of the excitation wavelength in the region 3164–584 A. A strong variation of the quantum yield with excitation wavelength is observed. The results are...

Transfer of Energy in Solid Plastic Solutions

The mechanism of energy transfer from excited solvent molecules to the solute, in plastic phosphors is investigated. Energy transfer efficiencies in styrene and polystyrene solutions are compared. The question whether the phenomenon of energy transfer in plastic systems is the consequence of an intramolecular process in the polymer molecule, is discussed. It is shown that such a process is not an essential condition for high‐energy transfer efficiency in plastic solutions. The experimental data furnish strong evidence that energy transfer is the result of intermolecular processes, similar to those occurring in liquid solutions.