soil samples were collected from seven sites in and around the metropolitan area of mexicocity. the locations were chosen as possible sources of fugitive dusts which contribute to suspended particulate matter in the atmosphere of mexico city. x-ray fluorescence (xrf) was used to determine the concentrations of several major elements (si, k, ca, ti, mn, and fe), as well as of other trace element...

This technique combines the advantages of magnification and stereoscopic angiography. A heavy-duty x-ray tube oscillating between two positions (25 mm apart) allows serial spinal angiograms to be produced in stereo magnification (factor 2.0) using the 0.2 mm, 12 kW focal spot. The x-ray tube can be rapidly changed for normal serial angiography with a 0.6 mm, 50 kW focus. The technique is easy t...

In accordance with a questionnaire survey of diagnostic X-ray equipment enforced in 2005, this report was focused mainly on a photography device. The paper questionnaire was mailed to 667 institutions, and the collection rate was 20.4%. Introductions of digital photographic devices are progressing and flat panel detectors (FPD) are spreading in addition to computed radiography (CR). Examination...

background: panoramic imaging is one of the most common imaging methods in dentistry. regarding the side-effects of ionizing radiation, it is necessary to survey different aspects and details of panoramic imaging. in this study, we compared the absorbed x-ray dose around two panoramic x-ray units: pm 2002 cc proline (planmeca, helsinki, finland) and cranex tome (soredex, helsinki, finland). mat...

T h e general introduction of the X-ray image intensifier (11) over the last decade has opened up new possibilities for X-ray examination. The brightness of the 11, which is several thousand times higher than the conventional fluorescent screen, allows the image to be viewed in normal room lighting. If a television chain is connected, the operator has control over contrast and brightness to fur...

Context. The maximum number density of Active Galactic Nuclei (AGNs), as deduced from X-ray studies, occurs at z <∼ 1, with lower luminosity objects peaking at smaller redshifts. Optical studies lead to a different evolutionary behaviour, with a number density peaking at z ≈ 2 independently of the intrinsic luminosity, but this result is limited to active nuclei brighter than the host galaxy. A...