scholarly journals The differential action of X-rays on tissue growth and vitality.―Part I

1929 ◽  
Vol 105 (738) ◽  
pp. 402-421 ◽  
Keyword(s):  
Biological Action ◽  
Tissue Growth ◽  
X Rays ◽  
Living Matter ◽  
X Ray ◽  
Clinical Observations ◽  
Technical Procedure ◽  
Component Wave ◽  
Theoretical Considerations ◽  
Differential Action

The investigation of the biological action of homogeneous X-radiation of different wave-lengths was commenced because many clinical observations point to the existence of what has been termed differential action, although theoretical considerations do not support such a view. Differential action may be defined as the association of changes in living matter with certain special wave-lengths in the X-ray spectrum. The investigation was performed with the chorio-allantoic membrane of the embryo which. The X-ray spectrometer was used as a source of the different radiations. A fine pencil of X-rays impinges on a crystal, various component wave-lengths being reflected at corresponding angles connected by the formula the investigation of the biological action of bomogeneous X-radiation of different wave-lengths was commenced because m any clinical observations point to the existence of what has been termed differential action, although theoretical considerations do not support such a view. differential action may by defined as tbs association of changes in living matter with certain special wave-lengths in the X-ray spectrum. The investigation was performed with chorio-allantoic membrane of the embryo which. The X-ray spectrometer was used as a source of the different radiations. A fine pencil of X-rays impinges on a crystal, various component wave-lengths being reflected at corresponding angles connected by the formula λ = 2 d sin θ (fig. 1, p. 405.). This gives a radiation which is very nearly homogeneous, but the energy is exceedingly small, a fact which has no doubt deterred many previous workers from using this method. The present paper is an extension and confirmation of certain observations contained in a preliminary communication to the ' Medical Journal of Australia .' A selective action by different wave-lengths is described and the subject matter is arranged as follows: ( a ) The chorio-allantoio membrane and related structures are described; ( b ) the technical procedure of exposing the specimen to X-radiation is given, followed by ( c ) an account of the X-ray effects obtained, with details of their development and their relation to control experiments; ( d ) a systematic exploration of the X-ray spectrum is then described, giving microscopic results, which are expressed graphically, and details of confirmatory experiments, followed by ( e ) a brisk account of the microscopic examination. A general discussion ( f ) follows, in which the form, graphical expression, and the relationship of stimulation to destruction is considered. An apparent neutralisation between different wave-lengths in their biological action is also discussed and the technical procedure and form of tire graphs is considered in this respect. In the concluding remark ( g ) Zeleotive action is considered in relation to the atomic structure of the tissue and the main deductions are summarised.

X-ray and radium beams in the therapy of nervous diseases

1930 ◽  
Vol 26 (2) ◽  
pp. 196-199
Author(s):  
R. Ya. Gasul
Keyword(s):  
Therapeutic Effect ◽  
Empirical Finding ◽  
Biological Action ◽  
First Year ◽  
X Rays ◽  
X Ray

It's no secret that the therapeutic effect of X-rays and radium rays was, one might say, an accidental empirical finding. This, however, did not mark the first radiotherapists (who were dermatologists) without data on the biological action of X-rays and radium rays, without an exact dosage, intuitively, in the very first year after the significant discoveries of Rontgen and Kunie, these radiant factors were initially applied in the field of dermatology (before 1902 they did not know anything about the deep action of the rays).

Tunable X-ray polarization reflector with perfect crystals

1999 ◽  
Vol 55 (5) ◽  
pp. 955-962 ◽  
Author(s):  
Y. Hasegawa ◽  
Y. Ueji ◽  
K. Okitsu ◽  
J. M. Ablett ◽  
D. P. Siddons ◽  
...  
Keyword(s):  
Bragg Reflector ◽  
Performance Characteristics ◽  
X Rays ◽  
Polarization Direction ◽  
Polarization Ratio ◽  
Transmitted Beam ◽  
Spectroscopic Measurements ◽  
X Ray ◽  
Theoretical Considerations ◽  
Linear Polarizer

The possibility of a transmission-type X-ray linear polarizer is investigated using a thin Bragg reflector as a polarizing filter. In this device, the transmitted beam (rather than the Bragg-reflected beam) is the useful output of the device. Consequently, the position and the direction of the transmitted beam are unchanged as the energy is changed, or even when the polarization direction to be filtered out is changed. Theoretical considerations as well as preliminary transmissivity measurements are presented. The use of perfect crystals of silicon and diamond is examined. A polarization ratio, defined as I_H/I_V, higher than 105 was observed in experiments to measure the performance characteristics of the proposed X-ray polarizing reflector. The transmission-type X-ray linear polarizer is well suited for spectroscopic measurements with polarized X-rays.

scholarly journals The differential action of X-rays on tissue, growth and vitality.—Part IV.—The biological reaction to X-radiation in relation to time

1930 ◽  
Vol 107 (751) ◽  
pp. 308-312 ◽  
Keyword(s):  
Early Stage ◽  
Wave Length ◽  
Intermediate Stage ◽  
Tissue Growth ◽  
X Rays ◽  
Reliability Factor ◽  
Long Period ◽  
Exposure Experiment ◽  
Biological Reaction ◽  
Differential Action

In the investigation of a selective action of homogeneous X-radiation on the allantoic membrane of the chick (Moppett, 1929), a constant time of exposure was adopted since one cannot assume that the "time factor" is expressed by a linear function. It was observed at an early stage that a considerable fluctuation in current supply did not materially after the biological reaction if the normal time of exposure were given. An experimental investigation was carried out using a wave-length of 0·5 Å. which produces a hypertrophic reaction with an exposure of ½ hour and an atrophic reaction in 1¼ hours, when other conditions are similar. The reaction shows up abruptly when the above values are exceeded, suggesting the breakdown of a process of repair and the phenomenon is aptly described by the term threshold dose. Typical experiments are given in the following table (I) and the results are represented by the letter A for atrophy, H for hypertrophy, and HA for an intermediate stage. Experiment 147 may be taken as a standard in which a certain quantity of energy is given over a period of 1 hour, the reaction being HA. In experiment 135, approximately the same does was given over a period of 2 hours and the reaction was increased to A+. The reliability factor 5/5 indicated that five consistent pairs of experiments showed an increased reaction in association with a longer time of exposure. Experiment 142 illustrates the fact that an increased reaction is obtained even if the exposure is given intermittently over a long period of time.

Some Developments in the X-ray Analysis of Single-Crystals

1927 ◽  
Vol 23 (5) ◽  
pp. 561-577
Author(s):  
R. L. Aston
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Incident Beam ◽  
X Rays ◽  
Surface Layers ◽  
X Ray ◽  
Axis Of Rotation ◽  
Component Wave

A method has been devised by Dr Alex Müller for determining the orientation of a single-crystal of metal by photographic measurement of the reflection of characteristic X-rays from surface layers. The incident beam passes perpendicularly through an axis of rotation around which the crystal is turned until a reflection is obtained with one of the component wave-lengths of the X-rays.

scholarly journals The differential action of X-rays on tissue, growth and vitality.— Part II. The biological reaction to X-radiation in relation to a phenomenon termed antagonism

1930 ◽  
Vol 107 (751) ◽  
pp. 293-301 ◽  
Keyword(s):  
Wave Length ◽  
Tissue Growth ◽  
Photographic Method ◽  
X Rays ◽  
Relative Resistance ◽  
Experimental Conditions ◽  
Two Factors ◽  
Biological Reaction ◽  
Embryo Chick ◽  
Differential Action

A selective action was observed when the allantoic membrane of the embryo chick was exposed to homogeneous X-radiation of different wave-length obtained by crystal diffraction (Moppett, 1929). In the same communication a phenomenon termed antagonism, which implies a neutralisation of the effects of different components of mixed radiation was deduced from the sensitivity of the tissue to homogeneous radiation and its relative resistance to mixed radiation. The rays "reflected" from the crystal produced a visible change in about the same period of time as the "direct" rays obtained by removing 1/1000 by a photographic method and this ration represents the relative potency of the two types of radiation under the experimental conditions described in the earlier paper. Antagonism appears to be a very striking phenomenon and it demands the condition that action must be in some respects selective so that the two factors may be considered together as a dual phenomenon.

scholarly journals THE KILLING OF COLON BACILLI BY X-RAYS OF DIFFERENT WAVE LENGTHS

1930 ◽  
Vol 52 (5) ◽  
pp. 769-780 ◽  
Author(s):  
Ralph W. G. Wyckoff
Keyword(s):  
Cell Volume ◽  
Biological Action ◽  
Experimental Results ◽  
X Rays ◽  
X Ray ◽  
Linear Fashion ◽  
Air Ionization

X-ray beams of wave lengths lying in the range between 4 A and 0.5 A all kill B. coli in a semilogarithmically linear fashion. Interpreted in terms of the known quantized absorption of X-rays, this means that one absorption of any of these radiations is sufficient to kill. Though death results from a single absorption, only about one hit in four with Ag K and one in sixty with Ag L radiation is deadly. The course of curves constructed from these experimental results suggests that the portion of this bacterium which is essential to its continued life has a total of approximately 0.01 of the cell volume. For copper and harder radiations the biological action of the rays is proportional to their measured air ionization. The same biological change with the softer chromium K. and silver L X-rays seems to require a somewhat more intensely ionizing beam.

scholarly journals The differential action of X-rays in relation to tissue growth and vitality. Part VI. —Tumour tissues

1932 ◽  
Vol 110 (766) ◽  
pp. 172-179 ◽  
Keyword(s):  
Tissue Growth ◽  
X Rays ◽  
Differential Action

This paper on tumour tissues is an extension of previous work on the reaction of the allantoic membrane to homogeneous X-radiation (1930, 1931), and the relation of such results to mixed radiation and to tissues generally. It is also an extension of work on the treatment of tumours with mixed radiation, of which Russ (1921) was a pioneer.

scholarly journals The differential action of X-rays on tissue, growth and vitality.—Part III. The biological reaction to X-radiation in relation to the area of tissue irradiated

1930 ◽  
Vol 107 (751) ◽  
pp. 302-307 ◽  
Keyword(s):  
Early Stage ◽  
Wave Length ◽  
Incident Radiation ◽  
Tissue Growth ◽  
X Rays ◽  
Selective Action ◽  
Imperfect Crystal ◽  
Biological Reaction ◽  
Embryo Chick ◽  
Differential Action

The allantoic membrane of the embryo chick was exposed to homogeneous X-radiation obtained by crystal diffraction and a selective action was observed (Moppett, 1929). A particular wave-length 0·53 Å. produced a hypertrophic reaction with an exposure of ½ hour and an atrophic reacion in 1¼ hours and this was adopted as a standard in the investigation of problems other than selective action (Moppett, 1929 and 1930). The Effect of Irradiating a Large or Small Area . A variation in effect with the area irradiated was suggested because at an early stage reactions were readily produced with an imperfect crystal and it was found that the results could be imitated by placing he specimen at an oblique angle to the incident radiation. It appears that the imperfect crystal was "convex," spreading the rays out to a greater extent than usual and various aspects of the problem are illustrated by the following typical experiments.

Simultaneous determination of tensile and shear strains of crystalline bilayers using three Bragg reflections of X-rays

2016 ◽  
Vol 49 (4) ◽  
pp. 1203-1208
Author(s):  
Yan-Zong Zheng ◽  
Ting-Wei Wu ◽  
Lien-Kuang Yu ◽  
Yong-Cheng Wei ◽  
Wen-Chung Liu ◽  
...  
Keyword(s):  
Simultaneous Determination ◽  
Tensile Strain ◽  
Diffraction Peak ◽  
X Rays ◽  
X Ray Diffraction ◽  
Si Substrate ◽  
X Ray ◽  
Theoretical Considerations ◽  
Gesi Layer

A method for the simultaneous determination of nine strain coefficients, both shear and tensile, of crystalline bilayers is proposed and realized. The X-ray diffraction peak intensities along 2θ (vertical) and β (horizontal) scans relative to the plane of incidence of three Bragg reflections whose atomic planes are not parallel to each other can be used to obtain shear and tensile strain coefficients. The theoretical considerations and experimental examples for single-crystal GeSi/Si overlayers are reported. It is also demonstrated that, for GeSi/Si, the shear and tensile strain coefficients of the Si substrate tend to vanish when the GeSi layer is thicker than 40 nm.

scholarly journals COVID-19 Pneumonia Detection Using Optimized Deep Learning Techniques

Diagnostics ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1972
Author(s):  
Abul Bashar ◽  
Ghazanfar Latif ◽  
Ghassen Ben Brahim ◽  
Nazeeruddin Mohammad ◽  
Jaafar Alghazo
Keyword(s):  
Deep Learning ◽  
Transfer Learning ◽  
Data Augmentation ◽  
Learning Algorithm ◽  
The Body ◽  
X Rays ◽  
X Ray ◽  
Clinical Observations ◽  
Dataset Size ◽  
Chest X Ray

It became apparent that mankind has to learn to live with and adapt to COVID-19, especially because the developed vaccines thus far do not prevent the infection but rather just reduce the severity of the symptoms. The manual classification and diagnosis of COVID-19 pneumonia requires specialized personnel and is time consuming and very costly. On the other hand, automatic diagnosis would allow for real-time diagnosis without human intervention resulting in reduced costs. Therefore, the objective of this research is to propose a novel optimized Deep Learning (DL) approach for the automatic classification and diagnosis of COVID-19 pneumonia using X-ray images. For this purpose, a publicly available dataset of chest X-rays on Kaggle was used in this study. The dataset was developed over three stages in a quest to have a unified COVID-19 entities dataset available for researchers. The dataset consists of 21,165 anterior-to-posterior and posterior-to-anterior chest X-ray images classified as: Normal (48%), COVID-19 (17%), Lung Opacity (28%) and Viral Pneumonia (6%). Data Augmentation was also applied to increase the dataset size to enhance the reliability of results by preventing overfitting. An optimized DL approach is implemented in which chest X-ray images go through a three-stage process. Image Enhancement is performed in the first stage, followed by Data Augmentation stage and in the final stage the results are fed to the Transfer Learning algorithms (AlexNet, GoogleNet, VGG16, VGG19, and DenseNet) where the images are classified and diagnosed. Extensive experiments were performed under various scenarios, which led to achieving the highest classification accuracy of 95.63% through the application of VGG16 transfer learning algorithm on the augmented enhanced dataset with freeze weights. This accuracy was found to be better as compared to the results reported by other methods in the recent literature. Thus, the proposed approach proved superior in performance as compared with that of other similar approaches in the extant literature, and it made a valuable contribution to the body of knowledge. Although the results achieved so far are promising, further work is planned to correlate the results of the proposed approach with clinical observations to further enhance the efficiency and accuracy of COVID-19 diagnosis.

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