Laser-Stimulated Luminescence Used to Measure X-ray Diffraction of a Contracting Striated Muscle

Abstract

An integrating x-ray area detector that operates on the basis of laser-stimulated luminescence was used in a diffraction study of muscle contraction. The area detector has a dynamic range of 1 to 10(5), a sensitivity about 60 times greater with approximately 1/300 as much fog background as x-ray film. It is erasable and reusable but, like film, can integrate at a practically unlimited counting rate. The high sensitivity and wide dynamic range of the detector resulted in a sufficient reduction in the exposure time to make possible the recording of a clear x-ray diffraction pattern, with up to 2.0-nanometer axial spacing, from a contracting frog skeletal muscle in as little as 10 seconds with synchrotron radiation. During the isometric contraction of the muscle, most of the actin diffraction lines increased in intensity without noticeable changes in their peak positions. Changes also occurred in diffraction intensities from the myosin heads. The results indicate that during contraction the structure of the actin filaments differs from that in the rigor state, suggesting a possible structural change in the actin subunits themselves; the myosin heads during contraction retain the axial periodicity of the myosin filament and become aligned in a more perpendicular manner to the actin filaments.

Dynamic electron microscopy of ATP-induced myosin head movement in living muscle thick filaments

“…The imaging plate was 10.2 ϫ 7.7 cm in size (2,045 ϫ 1,536 pixels), and had a sensitivity Ϸ60 times that of x-ray film (13). The exposure time was 0.1 s with a beam intensity of 1-2 ϫ 10 Ϫ12 A͞cm 2 .…”

Long-lasting phosphorescence in Mn2+:Zn2GeO4crystallites precipitated in transparent GeO2–B2O3–ZnO glass-ceramics

“…halogen ion deficit sites) act as electron trapping centers. The electron trapped in the F center, after X-ray irradiation, is released by excitation of a visible or an infrared laser, and subsequently recombines with a trapped hole, leading to emitted light whose intensity is proportional to the number of F centers, which in sample is proportional to the X-ray dose [4][5][6]. Photostimulated luminescent phosphors have been used as materials for two-dimension X-ray sensors [4,5].…”

X-ray Imaging: Status and Trends

“…18 The detector system consists of (a) a phosphor screen (the imaging plate); (b) an image reader; (c) an image processor; and (d) an image writer. The imaging plate is a flexible plastic plate coated with a 0.15 mm layer of phosphor crystals (BaFBr:Eu + 2)-When stimulated by scanning with a laser beam, the phosphor emits luminescence proportional to the absorbed x-ray dose.…”