Compact focusing spectrometer: visible (1 eV) to hard x-rays (200 keV).

A low-cost spectrometer that covers a wide range of photon energies can be useful to teach spectroscopy, and for simple, rapid measurements of the photon spectrum produced by small plasma devices. The spectrometer here achieves its wide range, nominally from 1 eV to 200 keV, with a series of spherically and cylindrically bent gratings or crystals that all have the same shape and the same radius of curvature; they are complemented by matching apertures and diagnostics on the Rowland circle that serves as the circular part of the spectrometer's vacuum vessel. Spectral lines are easily identified with software that finds their positions from the dispersion of each diffractive element and the known energies of the lines.

[A study of the effect of adrenaline on the transmembrane potential of the plasma membrane of hepatocytes from rats of different age using fluorescent probes].

The resting membrane potential of isolated hepatocytes from 2- and 20-month-old rats and its changes upon activation of cells by adrenaline have been studied by the method of quantitative microfluorimetry using diethyl derivatives of polymethine probes (H-510 and D-307). The potential was estimated by the Nernst equation adapted to lipophilic cationic probes. It was shown using both probes that the transmembrane potential of hepatocytes decreases with age. The microfluorimetry data were confirmed by the results of spectrofluorimetric measurements in a cell suspension. Changes in fluorescence occurring in adrenaline-activated single cells and suspensions were unidirectional, the effect of the hormone on the cells of old animals being less pronounced. The results indicate that the potential of the plasma membrane of individual hepatocytes can be adequately estimated by microfluorimetry, which can be used in metabolic and toxicologic investigations.

X-ray spectropolarimeter.

We have constructed a novel single-crystal x-ray spectropolarimeter that separates spatially the two perpendicularly polarized components of an x-ray beam. We have tested this device by using an x-ray tube, and confirmed its performance to be satisfactory as expected from its design.