scholarly journals MICROSCOPIC DETERMINATION OF BONE PHOSPHORUS BY QUANTITATIVE AUTORADIOGRAPHY OF NEUTRON-ACTIVATED SECTIONS

1965 ◽  
Vol 24 (1) ◽  
pp. 31-37 ◽  
Author(s):  
Jacques Vincent ◽  
Stanislas Haumont ◽  
Joseph Roels
Keyword(s):  
Cortical Bone ◽  
Bone Tissue ◽  
Mineral Composition ◽  
Optical Density ◽  
Absorption Curve ◽  
Thermal Neutrons ◽  
Γ Rays ◽  
Γ Ray ◽  
Ca:P Ratio

Longitudinal sections of human cortical bone were submitted to thermal neutrons. γ-ray spectra were recorded repeatedly during 15 days following irradiation. They showed that Na24 is predominant as early as 3 hours after activation and that all the γ-emitters have decayed on the 15th day. When the γ-rays have disappeared, ß-rays are still produced by the sections. It was proved by the absorption curve in aluminium that all these ß-rays are issued from the P32 induced in the sections by activation of P31. Therefore autoradiograms registered 15 days after activation reveal the distribution of P32 in the sections. γ-ray spectra and ß-ray absorption curves of neutron activated sections of ivory demonstrated a mineral composition similar to that of bone. Autoradiograms of ivory sections activated for various times were used to establish the relation between the optical density of the autoradiograms and the radioactivity in P32. When the bone autoradiograms are compared with the ivory standards of known radioactivity, the optical densities of single osteons (Haversian systems), can be related to their phosphorus contents. Autoradiograms and microradiograms of the same sections were examined side by side. The least calcified osteons, that contain 80 per cent of the calcium of the fully calcified osteons, also contain about 80 per cent of the phosphorus of the fully mineralized osteons. It is concluded that the Ca:P ratio remains constant while mineralization of bone tissue is being completed.

Relative intensities of prompt γ-rays from the 35Cl(n,γ)36Cl reaction with thermal neutrons as secondary γ-ray intensity standards

2013 ◽  
Vol 73 ◽  
pp. 60-67 ◽  
Author(s):  
Michihiro Shibata ◽  
Akinori Tojo ◽  
Itaru Miyazaki ◽  
Masataka Furuta ◽  
Hiroaki Hayashi ◽  
...  
Keyword(s):  
Thermal Neutrons ◽  
Γ Rays ◽  
Γ Ray

THE β- AND γ-RAYS OF ACTINIUM B AND ACTINIUM C″

1939 ◽  
Vol 17a (5) ◽  
pp. 82-102 ◽  
Author(s):  
B. W. Sargent
Keyword(s):  
Growth Curves ◽  
Absorption Curve ◽  
End Points ◽  
End Point ◽  
Order Of Magnitude ◽  
Γ Rays ◽  
Γ Ray ◽  
The Difference ◽  
First Time ◽  
Excitation Probability

The absorption method of finding the end-point of a β-ray spectrum has been made more precise and free of errors that are due to straggling and the γ-ray background. The absorption curves of the β-rays of radium E and uranium X2 were taken as standard, since, from experiments with the magnetic spectrograph, their end-points are known to be 1.15 and 2.32 Mev respectively. The extrapolated ranges of these fastest β-rays are, from experiments with homogeneous beams, 0.51 and 1.12 gm. per cm.2 of aluminium. In general the extrapolated range R can be expressed in terms of the energy E in Mev by the equation:[Formula: see text]for E > 0.6 Mev. It is shown that the final portions of the absorption curves of the β-rays from radium E and uranium X2 have the same shape when plotted against m/R, where m is the mass in gm. per cm.2 of absorber and R is the range of the fastest β-rays in the spectrum. The range and end-point of another β-spectrum can be found by fitting its absorption curve to the standard one.The absorption curve of the β-rays of actinium B was obtained separately from that of actinium C″ for the first time. Growth curves were plotted from measurements of the β-activity of the active deposit obtained by exposing aluminium foils to filtered actinon for a few minutes. The β-activity was measured through thickness of aluminium up to 0.32 gm. per cm.2 From the initial portions of the growth curves and from the absorption curve of the β-rays of actinium (B + C) in equilibrium, separate absorption curves were plotted which indicated ranges of 0.64 and 0.68 gm. per cm.2 of aluminium for the β-rays of actinium B and actinium C″ respectively. The corresponding end-points are 1.39 and 1.47 Mev.There is some evidence that the β-spectrum of actinium B consists of two primary components, namely, a strong one having an end-point at 1.39 Mev and a weak one having an end-point at about 0.5 Mev. The difference between the two end-points is approximately equal to the energy (0.83 Mev) of a γ-ray emitted in the transformation actinium B.C. The ratio of the numbers of β-particles in the two partial spectra is approximately 1:7. This gives an excitation probability of 0.12 for the 0.83 Mev level of the actinium C nucleus, which is of the same order of magnitude as that obtained from the intensities of the γ-rays.

scholarly journals Вивчення оптичної щільності щелепових кісток у хворих із радикулярними кістами на тлі остеопорозу та без порушень мінерального обміну

2017 ◽  
Author(s):  
S. T. Havryltsiv
Keyword(s):  
Bone Mineral Density ◽  
Bone Tissue ◽  
Optical Density ◽  
Bone Mineral ◽  
Ultrasonic Waves ◽  
Published Data ◽  
Mineral Density ◽  
Facial Skeleton ◽  
Jaw Bones

There is a signifi cant scientifi c and practical interest in the study of bone mineral density in the jaw destructive processes caused by tumors in patients without bone remodeling disorders on the background of osteoporosis.The aim of the study – to conduct a comparative evaluation of jaw bone optical density in areas adjacent to radicular cysts depending on the osteoregenerating status of patients.Materials and Methods. 45 patients (20 males and 25 females) aged 20 to 70 years with radicular jaw cysts who were on an outpatient treatment at the Surgical Department of the Medical Stomatological Center of Danylo Halytskyi Lviv National Medical University were examined. Determination of bone mineral density (BMD) in patients was conducted by ultrasound bone densitometer Achilles (LUNAR Corp. (USA)) by measuring the time of ultrasonic waves pass through the calcaneus. Bone mineral density in patients was analyzed for the Z criterion. All patients underwent standard orthopantomograms on an X-ray apparatus Orthophos XG (Sirona). For the qualitative characteristics of mandibular cortical layer we used MCI index (mandibular cortical index) by Klemetti E. et al. (1994). According to published data, the index serves as an indicator of MCI systematic reduction of mineral density of the facial skeleton. Digital orthopantomograms analyzed by using the ImageJ software, which allows measuring the optical density of bone tissue at any selected jawbone area in standard brightness units in grayscale from 0 to 256 (the minimum values correspond to the background of the radiographs). The optical density of bone tissue was determined in a region directly adjacent to the shell of the radicular cyst, and compared with the intact bone on the symmetrical side of the jaw. Statistical analysis of the research results was carried out by a computer program of statistical calculation Statistica 8.Results and Discussion. As a result of ultrasound densitometry of the calcaneus in 17 women aged 45 to 60 years, we found signs of osteopenia and osteoporosis. Indicators of BMD within the age norm were detectedin 6 surveyed women who were younger than 45 years. Among the surveyed men of all ages signs of age norms were found much more frequently – in 11 cases. The MCI mandible index is in 87 % of cases directly correlated with state of bone mineral density determined by ultrasound densitometry, which is being consisted with literature data. In the absence of systemic disorders of mineral metabolism, the parameters of optical density in areas adjacent to the shells of the radicular cysts were higher compared to intact bones (p <0.05), which, in our opinion, testifi es about the compensatory reaction of the bone tissue that is subjected to pathological infl uence (compression) from the side of the cyst shell. On the background of systemic osteoporosis, optic density of jaw bones in the area of injury compared to intact sides is decreased.Conclusions. Determination of the optical density of the jaw bones adjacent to the radicular cysts can be used as a screening test for the study of osteo-regenerative potential in patients and should be taken into account when choosing surgical treatment methods.

scholarly journals Radio pulsations from the γ-ray millisecond pulsar PSR J2039−5617

2020 ◽  
Author(s):  
A Corongiu ◽  
R P Mignani ◽  
A S Seyffert ◽  
C J Clark ◽  
C Venter ◽  
...  
Keyword(s):  
Radio Signal ◽  
Radio Pulse ◽  
Light Curves ◽  
Dispersion Measure ◽  
Pulse Profile ◽  
Orbital Inclination ◽  
Independent Determination ◽  
Γ Rays ◽  
Γ Ray

Abstract The predicted nature of the candidate redback pulsar 3FGL J2039.6−5618 was recently confirmed by the discovery of γ-ray millisecond pulsations (Clark et al. 2020, hereafter Paper I), which identify this γ-ray source as PSR J2039−5617. We observed this object with the Parkes radio telescope in 2016 and 2019. We detect radio pulsations at 1.4 GHz and 3.1 GHz, at the 2.6ms period discovered in γ-rays, and also at 0.7 GHz in one 2015 archival observation. In all bands, the radio pulse profile is characterised by a single relatively broad peak which leads the main γ-ray peak. At 1.4 GHz we found clear evidence of eclipses of the radio signal for about half of the orbit, a characteristic phenomenon in redback systems, which we associate with the presence of intra-binary gas. From the dispersion measure of 24.57 ± 0.03 pc cm−3 we derive a pulsar distance of 0.9 ± 0.2 kpc or 1.7 ± 0.7 kpc, depending on the assumed Galactic electron density model. The modelling of the radio and γ-ray light curves leads to an independent determination of the orbital inclination, and to a determination of the pulsar mass, qualitatively consistent to the results in Paper I.

Mineral composition and gemological characteristics of the fossil marine reptiles of the Ulyanovsk region

2018 ◽  
pp. 12-16 ◽  
Author(s):  
D. A. Petrochenkov
Keyword(s):  
Chemical Composition ◽  
Bone Tissue ◽  
Mineral Composition ◽  
Bone Structure ◽  
Upper Jurassic ◽  
Marine Reptiles ◽  
Ulyanovsk Region ◽  
Impurity Elements ◽  
Wide Assortment

Fossils of marine reptiles are a new jewelry and ornamental material and collected in the Ulyanovsk region from the Upper Jurassic deposits. They consist of (wt. %): calcite — 52, apatite — 24 and pyrite — 23, and also gypsum presents. The contents of radioactive and carcinogenic elements are close to background. The original bone structure of reptiles is preserved. Apatite replaces the bone tissue of marine reptiles, forming a cellular framework. According to the chemical composition, apatite refers to fluorohydroxyapatite with an increased Sr content. The size of the crystals is finely-dispersed. Calcite and pyrite fill the central parts of the cells. Calcite crystals of isometric and elongated shape, 0,01—0,05 mm in size, form blocks up to 0,3 mm during intergrowth. Calcite fills thin, discontinuous veins along the contour of cells with a width of up to 0,03 mm. In calcite, among the impurity elements, there are (wt. %, on the average): Mg — 0,30, Mn — 0,39 and Fe — 0,96. Pyrite forms a dispersed impregnation in calcite and apatite, content of impurities is, wt. %: Ni — up to 0,96 and Cu — up to 0,24. On technological and decorative characteristics of fossils of sea reptiles of Ulyanovsk region are qualitative jewelry and ornamental materials of biomineral group, allowing to make a wide assortment of jewelry and souvenir products.

The precision determination of some γ-ray energies using a β-spectrometer

1965 ◽  
Vol 63 (3) ◽  
pp. 353-382 ◽  
Author(s):  
G. Murray ◽  
R.L. Graham ◽  
J.S. Geiger
Keyword(s):  
Precision Determination ◽  
Γ Ray
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