scholarly journals STUDIES ON X-RAY EFFECTS

1922 ◽  
Vol 35 (4) ◽  
pp. 475-485 ◽  
Author(s):  
Waro Nakahara ◽  
James B. Murphy
Keyword(s):  
Small Dose ◽  
Biological Effect ◽  
Lymphoid Organs ◽  
X Rays ◽  
Thin Glass ◽  
X Ray ◽  
Spark Gap ◽  
Mitotic Figures ◽  
High Degree ◽  
Ray Effects

A study has been made of the biological effect of a small dose of soft x-rays given off by a special water-cooled tube with a window of thin glass, operated at ½ inch spark-gap and 11 milliamperes. Mice exposed for 1 minute show 2 days later in the blood an increase in the number of lymphocytes and in the lymphoid organs an increased number of mitotic figures. There occurs also a marked dilatation of the vessels of the suprarenals, particularly between the cortex and medulla. The latter condition did not appear until after 24 hours and was still present 14 days after the treatment. No change was detected in other organs. Mice treated in this way showed a high degree of resistance to cancer transplants. The amount of resistance varied with the time of the inoculation after the treatment. The resistance was not increased before 3 days after and was at its highest point 10 days after the treatment.

scholarly journals STUDIES ON X-RAY EFFECTS

1920 ◽  
Vol 31 (1) ◽  
pp. 13-29 ◽  
Author(s):  
Waro Nakahara ◽  
James B. Murphy
Keyword(s):  
Lymphoid Tissue ◽  
Proliferative Activity ◽  
X Rays ◽  
X Ray ◽  
Lymph Glands ◽  
Spark Gap ◽  
Mitotic Figures ◽  
Ray Effects ◽  
Stimulation Of

A dose of x-rays governed by the following factors induces a stimulation of lymphoid tissue in mice: spark-gap ⅞ inch, milliamperage 25, distance 8 inches, time of exposure 10 minutes. Within 4 days after this dose there appeared an abnormally large number of mitotic figures in the lymphoid tissue of spleen and lymph glands, indicating an acceleration of the proliferative activity of the tissue.

scholarly journals STUDIES ON X-RAY EFFECTS

1919 ◽  
Vol 29 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Marguerite M. Thomas ◽  
Herbert D. Taylor ◽  
William D. Witherbee
Keyword(s):  
The Other ◽  
X Rays ◽  
X Ray ◽  
Spark Gap ◽  
Before And After ◽  
Circulating Lymphocytes ◽  
Ray Effects

This study consists of blood counts on nine rabbits after an exposure to x-rays of a 7/8 inch spark-gap, milliamperage 25, distance from the target 8 inches, and time of exposure 20 minutes. In seven of the nine animals there resulted an increase of the circulating lymphocytes. In five of these the increase was marked and in two others definite but not striking. Of the two animals which showed no stimulation one showed marked fluctuation of counts both before and after x-rays and the other little or no change. The higher penetrating dose (6 inch spark-gap, milliamperage 5, distance from the target 10 inches, time 26 minutes and 57 seconds) given to two animals produced no appreciable stimulation.

scholarly journals STUDIES ON X-RAY EFFECTS

1919 ◽  
Vol 29 (1) ◽  
pp. 83-87 ◽  
Author(s):  
Waro Nakahara
Keyword(s):  
Small Dose ◽  
Lymphoid Tissue ◽  
X Rays ◽  
Destructive Effect ◽  
Slight Degree ◽  
X Ray ◽  
Lymph Glands ◽  
Ray Effects ◽  
Stimulation Of

1. The small dose of x-rays applied to the rabbit has no appreciable destructive effect on the lymphoid tissue. 2. Indications of stimulation of the lymphoid tissue appear immediately after the treatment, become most pronounced in 2 (in lymph glands) to 4 (in the spleen) days, and persist, in a slight degree, up to the 14th day. 3. These facts suggest that the lymphocytosis induced by the small dose of x-rays is due to a primary stimulative effect upon the lymphoid tissue of the animal.

scholarly journals STUDIES ON X-RAY EFFECTS

1921 ◽  
Vol 33 (4) ◽  
pp. 433-439 ◽  
Author(s):  
Waro Nakahara ◽  
James B. Murphy
Keyword(s):  
The State ◽  
X Rays ◽  
X Ray ◽  
Small Doses ◽  
Ray Effects ◽  
Lymphoid Proliferation ◽  
Marked Suppression

Mice treated with small doses of x-rays and inoculated with cancer immediately afterwards, show a marked suppression of lymphoid proliferation. If, however, the cancer inoculation is made 7 days after the exposure to x-rays, thus permitting the primary lymphoid stimulation known to occur soon after the x-ray treatment to arise, a second stimulation takes place in a large proportion of mice thus inoculated. Changes in the blood of mice x-rayed and inoculated with cancer 7 days afterwards show that the state of resistance to cancer inoculation is attended by blood lymphocytosis, as is the case in all other varieties of immunity to transplanted cancer so far studied.

scholarly journals Diffuse cosmic X-rays from non-thermal intergalactic bremsstrahlung

1970 ◽  
Vol 37 ◽  
pp. 392-401
Author(s):  
Joseph Silk
Keyword(s):  
Cosmic Rays ◽  
Intergalactic Medium ◽  
Energy Requirement ◽  
Cosmic Ray ◽  
X Rays ◽  
Degree Of Ionization ◽  
X Ray ◽  
Normal Galaxies ◽  
X Ray Background ◽  
High Degree

The diffuse X-ray background between 1 keV and 1 MeV is interpreted as non-thermal bremsstrahlung in the intergalactic medium. The observed break in the X-ray spectrum at ∼40 keV yields the heat input to the intergalactic medium, the break being produced by ionization losses of sub-cosmic rays. Proton bremsstrahlung is found not to yield as satisfactory an agreement with observations as electron bremsstrahlung: excessive heating tends to occur. Two alternative models of cosmic ray injection are discussed, one involving continuous injection by evolving sources out to a redshift of about 3, and the other model involving injection by a burst of cosmic rays at a redshift of order 10. The energy density of intergalactic electrons required to produce the observed X-rays is ∼ 10−4 eV/cm3. Assuming a high density (∼ 10−5 cm−3) intergalactic medium, the energy requirement for cosmic ray injection by normal galaxies is ∼ 1058–59ergs/galaxy in sub-cosmic rays. The temperature evolution of the intergalactic medium is discussed, and we find that a similar energy input is also required to explain the observed high degree of ionization (if 3C9 is at a cosmological distance).

An oscillographic study of the production of X-rays by a Coolidge tube

1924 ◽  
Vol 22 (1) ◽  
pp. 70-75 ◽  
Author(s):  
J. A. Crowther
Keyword(s):  
Measuring Instruments ◽  
X Rays ◽  
X Ray ◽  
Spark Gap ◽  
High Tension

Radiologists have often had cause to note certain apparent anomalies in the behaviour of their apparatus. It is quite well known that different X-ray tubes, excited by different kinds of high tension apparatus, yield X-radiation of markedly varying quality and quantity even under conditions which, as measured by spark gap and milliammeter (the usual measuring instruments of the radiologist), are apparently identical. These anomalies seemed to offer an interesting field for investigation, and one which might not be without value on the practical side.

GENERATION OF X-RAYS WITH A HIGH DEGREE OF LONGITUDINAL COHERENCE

2007 ◽  
Vol 21 (03n04) ◽  
pp. 513-518
Author(s):  
ROBERT ROSSMANITH
Keyword(s):  
Synchrotron Radiation ◽  
Storage Rings ◽  
Light Sources ◽  
X Rays ◽  
X Ray ◽  
Electron Accelerators ◽  
Longitudinal Coherence ◽  
High Degree

Synchrotron radiation produced either in storage rings or SASE-FELs is longitudinally incoherent. In this paper a way to produce short longitudinally coherent X-ray pulses is discussed. In addition it is investigated if these sources can be modified to use them as light sources for vacuum electron accelerators.

scholarly journals Divergent-beam X-ray photography of crystals

1947 ◽  
Vol 240 (817) ◽  
pp. 219-250 ◽  
Keyword(s):  
Wave Length ◽  
Impurity Content ◽  
Type I ◽  
X Rays ◽  
Divergent Beam ◽  
X Ray ◽  
Air Temperatures ◽  
High Degree ◽  
Good Agreement

Divergent-beam X-ray photography of single crystals by transmission can be used to study the ‘extinction’, that is, the diminution of the transmitted radiation that takes place at the Bragg reflexion angles. The intensity and geometry of the absorption lines observed give useful information about the texture of the crystal. Divergent beam photographs have shown that many crystals of organic compounds are unexpectedly perfect, and that sudden cooling to liquid-air temperatures will increase the mosaic character of their structure by an important factor and make them more suitable for structural analysis by the usual methods. Type I diamonds, and natural ice even near to its melting-point, are also found to possess a high degree of perfection, which cannot be removed by liquid-air treatment. The divergent beam method may be used for the determination of orientation, but it is important that the wave-length of X-rays employed should be correctly related to the size and nature of the crystal. In certain favourable cases it is possible to make precision measurements of lattice constant or of wave-length from divergent beam photographs, without the use of any kind of precision apparatus. By such means it has been shown that the C—C distance in individual diamonds varies from 1541.53(± 0-02) to 1541.27X, (1.54465-1-54440A), a difference presumably due to varying impurity content. Using diamond and a brass anticathode, the Zn Ka 1 wave-length, relative to Cu K Ka 1 as 1537.40X, is found to be 1432.21 ( ± 0-04) X. Temperature control would improve the accuracy of this measurement, which is, however, in good agreement with the latest value obtained by orthodox precision methods.

X-Ray Investigation of the Amorphous State of Rubber

1955 ◽  
Vol 28 (3) ◽  
pp. 728-731 ◽  
Author(s):  
V. I. Kasatochkin ◽  
B. V. Lukin
Keyword(s):  
Diffraction Pattern ◽  
Amorphous State ◽  
Coherent Scattering ◽  
X Rays ◽  
X Ray Diffraction ◽  
Molecular Liquids ◽  
X Ray ◽  
Large Molecules ◽  
Molecular Substances ◽  
High Degree

Abstract The x-ray diffraction pattern of amorphous rubber, which is an amorphous ring, resembles the pattern of low-molecular liquids. In our previous work, it was established that the diffraction pattern observed is due to the coherent scattering of only those segments of the molecular chains in which the aggregation is analogous to that of low-molecular liquids, and is determined by the presence of a pseudo-order. A large part of the links of the molecular chains, owing to the prevailing disorder, scatters the x-rays incoherently, like scattering by a gas. For one component of amorphous rubber, the concept of “liquid phase” was introduced, and, for the other, that of “gaseous phase”, thereby subdividing them according to the type of scattering of x-rays. Amorphous rubber, according to our data, contains a large number of chair segments which are characterized by a high degree of disorder. The presence of such a disordered molecular phase is a general and characteristic property of high-molecular substances, and is caused by natural obstacles in the dense packing of the large molecules. This characteristic of molecular aggregation is undoubtedly reflected in the physical-mechanical properties of polymers.

scholarly journals Ptychographic X-ray speckle tracking with multi-layer Laue lens systems

2020 ◽  
Vol 53 (4) ◽  
pp. 927-936 ◽  
Author(s):  
Andrew J. Morgan ◽  
Kevin T. Murray ◽  
Mauro Prasciolu ◽  
Holger Fleckenstein ◽  
Oleksandr Yefanov ◽  
...  
Keyword(s):  
High Resolution ◽  
Speckle Tracking ◽  
X Rays ◽  
Chemical Sensitivity ◽  
X Ray ◽  
Laue Lens ◽  
Layer Deposition ◽  
Recent Developments ◽  
Ray Path ◽  
High Degree

The ever-increasing brightness of synchrotron radiation sources demands improved X-ray optics to utilize their capability for imaging and probing biological cells, nano-devices and functional matter on the nanometre scale with chemical sensitivity. Hard X-rays are ideal for high-resolution imaging and spectroscopic applications owing to their short wavelength, high penetrating power and chemical sensitivity. The penetrating power that makes X-rays useful for imaging also makes focusing them technologically challenging. Recent developments in layer deposition techniques have enabled the fabrication of a series of highly focusing X-ray lenses, known as wedged multi-layer Laue lenses. Improvements to the lens design and fabrication technique demand an accurate, robust, in situ and at-wavelength characterization method. To this end, a modified form of the speckle tracking wavefront metrology method has been developed. The ptychographic X-ray speckle tracking method is capable of operating with highly divergent wavefields. A useful by-product of this method is that it also provides high-resolution and aberration-free projection images of extended specimens. Three separate experiments using this method are reported, where the ray path angles have been resolved to within 4 nrad with an imaging resolution of 45 nm (full period). This method does not require a high degree of coherence, making it suitable for laboratory-based X-ray sources. Likewise, it is robust to errors in the registered sample positions, making it suitable for X-ray free-electron laser facilities, where beam-pointing fluctuations can be problematic for wavefront metrology.

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