scholarly journals DELAYED FORMATION OF CHROMOSOME ABERRATIONS IN MOUSE PACHYTENE SPERMATOCYTES TREATED WITH TRIETHYLENEMELAMINE (TEM)

Genetics ◽  
1977 ◽  
Vol 85 (1) ◽  
pp. 65-72
Author(s):  
W M Generoso ◽  
M Krishna ◽  
R E Sotomayor ◽  
N L A Cacheiro
Keyword(s):  
Chromosome Aberrations ◽  
The Other ◽  
X Rays ◽  
Cytological Analysis ◽  
Marked Contrast ◽  
Lethal Effects ◽  
X Ray ◽  
Lethal Mutations ◽  
Pachytene Spermatocytes ◽  
Metaphase I

ABSTRACT Induction of chromosome aberrations in pachytene spermatocytes of mice by 2 mg/kg TEM was compared with induction by 400 R X rays. These doses induced comparably high dominant lethal effects in pachytene spermatocytes of mice. Cytological analysis at diakinesis-metaphase I stage showed that whereas 76.4% of the cells treated with X rays at pachytene stage had aberrations, the frequencies observed in two TEM experiments were only 0.8 and 2.2%. On the other hand, 5% of the progeny from TEM-treated pachytene spermatocytes were found to be translocation heterozygotes. This is the first report on the recovery of heritable translocations from treated spermatocytes of mice. The aberration frequencies observed for TEM in diakinesis-metaphase I were much too low to account for all the lethal mutations and heritable translocations. Thus, the formation of the bulk of aberrations induced by TEM in pachytene spermatocytes was delayed-a marked contrast to the more immediate formation of X-ray-induced aberrations. It is postulated that the formation of the bulk of TEM-induced aberrations in pachytene spermatocytes and in certain postmeiotic stages occurs sometime during spermiogenesis, and not through the operation of postfertilization pronuclear DNA synthesis.

scholarly journals HIGH RATES OF OCCURRENCE OF SPONTANEOUS CHROMOSOME ABERRATIONS IN DROSOPHILA MELANOGASTER

Genetics ◽  
1976 ◽  
Vol 83 (2) ◽  
pp. 409-422
Author(s):  
Osamu Yamaguchi ◽  
Ricardo A Cardellino ◽  
Terumi Mukai
Keyword(s):  
Chromosome Aberrations ◽  
Gene Arrangement ◽  
Reciprocal Translocations ◽  
Lethal Effects ◽  
Recessive Lethal ◽  
The Third ◽  
Lethal Mutations ◽  
Pericentric Inversions ◽  
Break Points ◽  
Spontaneous Chromosome

ABSTRACT Spontaneous mutations were accumulated for 40 generations in 140 unrelated second chromosomes with the standard gene arrangement. These were extracted from the same population by using the marked inversion technique, and the following findings were obtained: (1) In 42 out of the 140 chromosome lines, chromosome aberrations were detected by examining the salivary gland chromosomes: 40 paracentric and 15 pericentric inversions, 2 reciprocal translocations between the second and the third chromosomes, and 6 transpositions. (2) In 63 out of the 90 originally lethal-free lines, recessive lethal mutations occurred. (3) There were only 3 lines that acquired chromosome aberrations (inversions) with no lethal effects in the homozygous condition. (4) In a comparison of these results with those of the (CH), (PQ), and (RT) chromosomes in which no chromosome aberrations occurred after accumulating mutations for 22058 chromosome·generations (Yamaguchi and Mukai 1974), it was concluded that some of these 140 chromosomes carried a kind of mutator. (5) The frequency of mutator-carrying chromosome lines was estimated to be 0.66 on the basis of the distribution of the break-points on the chromosome lines and the frequency of lines that acquired neither recessive lethal mutations nor chromosome aberrations. Thus, the average number of breaks per mutator-carrying chromosome was estimated to be about 0.19/generation. On the basis of these estimates, the nature of the mutator factor was discussed.

Isoelastic Cementless Total Hip Replacement in Rheumatoid Arthritis. Long-Term Results

1992 ◽  
Vol 2 (2) ◽  
pp. 43-46
Author(s):  
U. Fusco ◽  
R. Capelli ◽  
A. Avai ◽  
M. Gerundini ◽  
L. Colombini ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Hip Replacement ◽  
The Other ◽  
Long Term Results ◽  
X Rays ◽  
X Ray ◽  
The Mean ◽  
Cementless Total Hip Replacement

Between 1980 and 1987 we have implanted 46 isoelastic cementless THR in 40 patients affected with rheumatoid arthritis. We have reviewed 38 hips clinically and by X-ray. The mean follow-up was 8,5 years. Harris hip scores ranged from 30.6 preoperatively to 73,4 post-operatively when reviewed. While on the other hand Merle D'Aubigné hip scores ranged from 7,06 pre-operatively to 15,59 post-operatively. All patients have been satisfied, and X-rays showed an improvement for both Charnely and Gruen X-ray score.

scholarly journals THE SKIN REACTIONS PRODUCED BY ALTERNATIONS OF HEAT AND X-RAY AT VARIOUS TIME INTERVALS

1931 ◽  
Vol 53 (3) ◽  
pp. 405-411 ◽  
Author(s):  
James A. Hawkins
Keyword(s):  
Guinea Pig ◽  
The Other ◽  
X Rays ◽  
Time Intervals ◽  
Skin Reactions ◽  
X Ray ◽  
Critical Dose

Areas on the abdomen of the same guinea pig were exposed to suberythemal doses of soft X-rays, to heat of an intensity below the critical dose for the production of burns, and to both radiations in sequence with various time intervals between the exposures. The only effect of exposure to X-ray or heat alone was a slight scaling of the skin. The areas exposed to heat and X-radiation developed well-marked and persistent burns when the exposure to one agent was made within 3 hours of the other. Scaling of the skin developed when the exposure to one agent was made 1 day after the other. This scaling was more marked and lasted longer than the scaling produced by either agent alone. The results were the same no matter in which sequence the agents were applied.

scholarly journals Supersoft X-ray nebulae in the Large Magellanic Cloud

2020 ◽  
Vol 497 (3) ◽  
pp. 3234-3250 ◽  
Author(s):  
Diego A Farias ◽  
Alejandro Clocchiatti ◽  
Tyrone E Woods ◽  
Armin Rest
Keyword(s):  
Interstellar Medium ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
The Other ◽  
X Rays ◽  
X Ray ◽  
Upper Limits ◽  
Type Ia ◽  
Source Models ◽  
Flux Measurements

ABSTRACT Supersoft X-rays sources (SSSs) have been proposed as potential Type Ia supernova (SN Ia) progenitors. If such objects are indeed persistently X-ray luminous and embedded in sufficiently dense interstellar medium (ISM), they will be surrounded by extended nebular emission. These nebulae should persist even long after an SN Ia explosion, due to the long recombination and cooling times involved. With this in mind, we searched for nebular [O iii] emission around four SSSs and three SNRs in the Large Magellanic Cloud, using the 6.5-m Baade telescope at Las Campanas Observatory and the imacs camera. We confirm that, out of the four SSS candidates, only CAL 83 can be associated with an [O iii] nebula. The [O iii] luminosity for the other objects is constrained to ≲17 per cent of that of CAL 83 at 6.8 pc from the central source. Models computed with the photoionization code cloudy indicate that either the ISM densities in the environments of CAL 87, RX J0550.0-7151, and RX J0513.9-6951 must be significantly lower than surrounding CAL 83 or the average X-ray luminosities of these sources over the last ≲10  000 yr must be significantly lower than presently observed, in order to be consistent with the observed luminosity upper limits. For the three SNRs we consider (all with ages <1000 yr), our [O iii] flux measurements together with the known surrounding ISM densities strongly constrain the ionizing luminosity of their progenitors in the last several thousand years, independent of the progenitor channel.

Identification of Lead and Other Elements in Ceramic Glazes and Housewares by 109Cd-Induced X-Ray Fluorescence Emission Spectrometry

1995 ◽  
Vol 78 (2) ◽  
pp. 407-412 ◽  
Author(s):  
David L Anderson ◽  
William C Cunningham ◽  
Tyler R Lemdstrom ◽  
Ilhan Olmez
Keyword(s):  
Limit Of Detection ◽  
Screening Method ◽  
Fluorescence Emission ◽  
The Other ◽  
Fluorescence Spectrometry ◽  
Emission Spectrometry ◽  
X Rays ◽  
Nondestructive Analysis ◽  
X Ray ◽  
Lower Count

Abstract Radioisotope x-ray fluorescence spectrometry was investigated as a potential screening method for Pb and other elements in housewares. Thirty-six commercial houseware items and 87 ceramic test tiles (85 fired with hobby glazes and 2 blank bisques) were examined qualitatively for the presence of Pb by using 109Cd-induced L x-ray fluorescence emission spectrometry. For the housewares, the technique provided fast, nondestructive analysis of areas with about 10 cm diameters (general regions) to about 4 mm diameters (isolated design regions). Pb was found in 25 of 28 ceramicware items, in all 8 other housewares, and in all the testtile glazes above the limit of detection of 1 count per second (cps) for Pb Lβ x-rays. For housewares, Pb identification did not always correspond to Pb leachability. For 68 test-tile glazes labeled as containing Pb (39 of which were also labeled ‘dinnerware safe’ or ‘safe for food containers’), count rates ranged from 290 to 730 cps, whereas for the other 17 glazes labeled (with one exception) ‘nontoxic,’ much lower count rates (5–61 cps) were obtained. Other elements found in the housewares or test glazes were As, Au, Ca, Co, Cr, Cu, Fe, Mn, Nb, Ni, Rb, Sr, Y, Zn, and Zr.

Micromachining in Plastics Using X-Ray Lithography for the Fabrication of Micro-Electrophoresis Devices

1999 ◽  
Vol 121 (1) ◽  
pp. 13-21 ◽  
Author(s):  
S. M. Ford ◽  
J. Davies ◽  
B. Kar ◽  
S. D. Qi ◽  
S. McWhorter ◽  
...  
Keyword(s):  
Fiber Optic ◽  
Rapid Analysis ◽  
The Other ◽  
Sample Introduction ◽  
Uv Exposure ◽  
X Rays ◽  
Pmma Substrate ◽  
X Ray ◽  
Positive Photoresist ◽  
Potential Applications

Micromachining was performed in polymethylmethacrylate (PMMA) using X-ray lithography for the fabrication of miniaturized devices (microchips) for potential applications in chemical and genetic analyses. The devices were fabricated using two different techniques: transfer mask technology and a Kapton® mask. For both processes, the channel topography was transferred (1:1) to the appropriate substrate via the use of an optical mask. In the case of the transfer mask technique, the PMMA substrate was coated with a positive photoresist and a thin Au/Cr plating base. Following UV exposure, the resist was developed and a thick overlayer (∼3 μm) of Au electroplated onto the PMMA substrate only where the resist was removed, which acted as an absorber of the X-rays. In the other technique, a Kapton® film was used as the X-ray mask. In this case, the Kapton® film was UV exposed using the optical mask to define the channel topography and following development of the resist, a thick Au overlayer (8 μm) was electrodeposited onto the Kapton® sheet. The PMMA wafer during X-ray exposure was situated directly underneath the Kapton® mask. In both cases, the PMMA wafer was exposed to soft X-rays and developed to remove the exposed PMMA. The resulting channels were found to be 20 μm in width (determined by optical mask) with channel depths of ∼50 μm (determined by x-ray exposure time). In order to demonstrate the utility of this micromachining process, several components were fabricated in PMMA including capillary/chip connectors, injectors for fixed-volume sample introduction, separation channels for electrophoresis and integrated fiber optic fluorescence detectors. These components could be integrated into a single device to assemble a system appropriate for the rapid analysis of various targets.

Quantitative Determimatioh of Sulfur, Chlorine, Potassium, Calcium, Scandium and Titanium in Aqueous Solutions by Radioisotopic Excited Fluorescent Spectrometer and by Conventional X-Ray Spectrometer

1970 ◽  
Vol 14 ◽  
pp. 102-126 ◽  
Author(s):  
Frank L. Chan ◽  
W. Barclay Jones
Keyword(s):  
Particle Size ◽  
Aqueous Solutions ◽  
Experimental Results ◽  
The Other ◽  
X Rays ◽  
Helium Atmosphere ◽  
X Ray ◽  
Effect Of Particle Size ◽  
The One

AbstractAn x-ray spectrometer with experimental results is herewith described using a radiosotope source Fe55 having a halflife of 2.6 years. As a result of the disintegration, the managanese x-rays are capable of exciting fluorescent x-rays of such elements as sulfur, chlorine, potassium, calcium, scandium and titanium in aqueous solutions. These elements with the Ka wavelengths ranging from 5.3729 Å to 2.7496 Å may be designated as between the very soft x-rays on the one hand and the hard x-rays on the other. The x-ray spectrometer presently described has achieved a resolution of 136 ev, FWHM.Simultaneously, these elements have also been quantitatively determined by conventional x-ray fluorescent spectrometers. Since one of the spectrometers is designed to operate in vacuum as well as in helium or air, determination of sulfur, potassium and calcium were carried out in vacuum. Determination of chlorine was carried out in a helium atmosphere, Calcium, scandium and titanium were determined in air with an air-path spectrometer.In the present study aqueous solutions containing these elements were used. The use of aqueous solutions has the inherent advantages of being homogeneous and free from effect of particle size.

Energy-Dispersive X-ray Spectrometry Performance on Multiple Transmission Electron Microscope Platforms

2010 ◽  
Author(s):  
James Demarest ◽  
Chris Deeb ◽  
Thomas Murray ◽  
Hong-Ying Zhai
Keyword(s):  
State Of The Art ◽  
Analytical Tool ◽  
The Other ◽  
Energy Dispersive ◽  
X Rays ◽  
X Ray ◽  
Root Cause ◽  
Analytical Tem ◽  
Transmission Electron ◽  
Multiple Transmission

Abstract Energy-dispersive X-ray spectrometry (EDS) is a key analytical tool aiding root cause determination in the failure analysis (FA) process. This paper looks at a number of analytical TEM microscopes currently in use in various facilities: microscope A, a STEM operated at 200kV; microscope B, a 300kV TEM; and microscopes C and D, both 200kV TEMs. EDS counts per unit time from multiple microscope platforms were examined. Microscope D demonstrated two orders of magnitude higher counts per unit time than the other three microscopes. Microscope D represents the state-of-the-art EDS analytical TEM configuration and has achieved this through a novel windowless EDS configuration which significantly increases the detector area (by about a factor of three) that receives X-rays generated from the sample.

Rotating crystal X-Ray photographs

1927 ◽  
Vol 21 (117) ◽  
pp. 258-271 ◽  
Author(s):  
Gilbert Greenwood
Keyword(s):  
Flat Plate ◽  
Ionization Chamber ◽  
The Other ◽  
X Rays ◽  
X Ray ◽  
Chamber Method ◽  
Powder Method ◽  
Small Crystal ◽  
Royal Institution

Since the original experiments of M. von Laue on the diffraction of X-rays by crystals, other and more suitable methods of research have been devised. The Bragg ionization-chamber method and the Debye-Scherrer powder method are now quite well known. The newest technique is that of the so-called 'rotating crystal', which is based essentially on some experiments of M. de Broglie. This method was first employed and developed in the Kaiser Wilhehm Institut für Faserstoffchemie in Berlin. It has recently been extended by the work of J. D. Bernal in the Royal Institution in London.There are two methods of making this type of photograph. In both a small crystal is rotated in a beam of X-rays and the reflected beams recorded photographically, in one case on a flat plate, and in the other on a cylindrical film the axis of which coincides with the axis about which the crystal is rotated.

scholarly journals On the interpretation of X-ray, single crystal, rotation photographs

1926 ◽  
Vol 113 (763) ◽  
pp. 117-160 ◽  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
The Other ◽  
X Rays ◽  
X Ray ◽  
Powder Method ◽  
Convenient Form ◽  
Other Hand ◽  
Rotation Method ◽  
Laue Method

In the development of the study of crystals by X-rays the methods used divide themselves naturally into four types : the Bragg Ionisation Spectrometer method, the Laue method, the Powder method of Debye and Scherrer, and the Rotating Crystal method of Rinne, Schiebold and Polyani. The techniques of the first three of these methods are fully explained in such books as ‘ X-Rays and Crystal Structure,’ by W. H. and W. L. Bragg, ‘ The Structure of Crystals,’ by Wyckoff, and ‘ Krystalle und Rontgenstrahlen,’ by Ewald, as well as in original papers. On the other hand, the rotation method is only slightly touched on in these works, the literature is scattered in a great number of papers, and the technique has not so far been described at any length in a convenient form. Particularly in English, references to it are scanty. In this paper the author has tried to give a concise account of the method, together with various types of charts and tables as it is used in the Davy Faraday Laboratory. The methods described differ in certain respects from those used on the Continent,* but they have been found to be rapid and sufficiently accurate.

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