scholarly journals The effect of X-rays on the glucose and hexose-phosphate glycolysis of tumour tissue

1939 ◽  
Vol 127 (847) ◽  
pp. 223-237 ◽  
Keyword(s):  
Cell Metabolism ◽  
Lethal Effect ◽  
Clinical Approach ◽  
X Rays ◽  
Trial And Error ◽  
Hexose Phosphate ◽  
One Step ◽  
Γ Rays ◽  
Work Done ◽  
Different Tissues

The clinical approach to questions concerning the effect of X-rays γ-rays on cells has, of necessity, been highly empirical. By methods of trial and error, in fact by experience, it has been found that certain tissues are more easily injured by radiation than others, certain types of tumour more responsive than others to treatment by irradiation. The experiments described here and in previous papers (Holmes 1933, 1935) on the effects of irradiation upon cell metabolism have also been conducted on empirical lines. They represent simply an attempt to carry the work done by others on the lethal effect of the rays one step further and to describe this effect in terms of cell metabolism. The possibility that detectable differences in the metabolism of different tissues may account for their variability in response to radiation must also be considered, and such experiments may eventually provide the data necessary for investigating this possibility.

WHY MEASUREMENT OF RADIATION DOSE BY MEDICAL PHYSICIST AND RADIATION ONCOLOGIST BOTH?

2021 ◽  
pp. 219-222
Author(s):  
Rubina Rubina ◽  
Baig M.Q ◽  
Kumar Dev
Keyword(s):  
Radiation Dose ◽  
Gamma Rays ◽  
Biological Effect ◽  
Radiation Energy ◽  
The Body ◽  
X Rays ◽  
Radiation Oncologist ◽  
X Ray ◽  
Γ Rays ◽  
Different Tissues

Many years after the discovery of X-ray's and gamma rays. They have been used empirically in medicine, later on realized that this approach was dangerous mainly in radiotherapy and up to some extent in diagnostic radiology. Thus Means of measuring x-ray/γ-rays had to be found in terms of unit of x-rays quantity dened and accepted. The magnitude of the biological effect desirable in case therapy and undesirable in case of diagnosis. It depends upon how much radiation energy is absorbed by irradiated material. X-ray dosimetry is the measurement of energy absorbed in any material particularly in different tissues of the body.

MOLECULAR MODELING OF THERMAL AND MECHANICAL PROPERTIES OF ELASTOMERS: A REVIEW

2013 ◽  
Vol 86 (3) ◽  
pp. 401-422 ◽  
Author(s):  
Kshitij C. Jha ◽  
Mesfin Tsige
Keyword(s):  
Microphase Separation ◽  
Material Design ◽  
Trial And Error ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Network Building ◽  
High Structural Stability ◽  
Micro Level ◽  
Architecture Modeling ◽  
Work Done

ABSTRACT Elastomers have varied applications from adhesives, sealants, encapsulants, and coatings to specialty usage in electronics, aviation, optical, and communications industries due to their high structural stability. In addition, more and more biological applications of elastomeric compounds are gaining ground, particularly in mimetic architecture. Modeling and simulation provide tools by which the interactions leading to various structure–property relationships can be explored at the micro level. An understanding of these processes could cut down on the extensive and expensive trial-and-error experiments as well as provide a benchmark for material design. This review article explores the work done by different groups, especially at the molecular level, to model the properties of both thermoplastic and thermoset elastomers. Each presents its own challenges and solutions: from microphase separation to network building and force field parameterization. The results of these modeling efforts along with the challenges are presented in this review work.

Surface and Adhesive Properties of Low-Density Polyethylene after Radiation Cross-Linking

2014 ◽  
Vol 606 ◽  
pp. 265-268 ◽  
Author(s):  
Martin Bednarik ◽  
David Manas ◽  
Miroslav Manas ◽  
Martin Ovsik ◽  
Jan Navratil ◽  
...  
Keyword(s):  
Electron Beam ◽  
High Performance ◽  
Chemical Properties ◽  
Low Density Polyethylene ◽  
Cross Linking ◽  
Low Density ◽  
X Rays ◽  
Radiation Processing ◽  
Adhesive Properties ◽  
Γ Rays

Radiation cross-linking gives inexpensive commodity plastics and technical plastics the mechanical, thermal, and chemical properties of high-performance plastic. This upgrading of the plastics enables them to be used in conditions which they would not be able to with stand otherwise. The irradiation cross-linking of thermoplastic materials via electron beam or cobalt 60 (gammy rays) is performed separately, after processing. Generally, ionizing radiation includes accelerated electrons, gamma rays and X-rays. Radiation processing with an electron beam offers several distinct advantages when compared with other radiation sources, particularly γ-rays and x-rays. The process is very fast, clean and can be controlled with much precision. There is no permanent radioactivity since the machine can be switched off. In contrast to γ-rays and x-rays, the electron beam can steered relatively easily, thus allowing irradiation of a variety of physical shapes. The energy-rich beta rays trigger chemical reactions in the plastics which results in networking of molecules (comparable to the vulcanization of rubbers which has been in industrial use for so long). The energy from the rays is absorbed by the material and cleavage of chemical bonds takes place. This releases free radicals which in next phase from desired molecular bonds. This article describes the effect of radiation cross-linking on the surface and adhesive properties of low-density polyethylene.

scholarly journals Evaluation the Safety and Security Procedures used In X-ray Clinics in Al-Harthiya-Baghdad

2021 ◽  
Vol 2114 (1) ◽  
pp. 012009
Author(s):  
Thuraya A. Abdul Hussian ◽  
Anwar kh. Farman
Keyword(s):  
Ionizing Radiation ◽  
X Rays ◽  
X Ray ◽  
Beta Particles ◽  
Medical Clinics ◽  
Γ Rays ◽  
Health Laws ◽  
Different Sources ◽  
Α Particles ◽  
Security Procedures

Abstract Radiation is a form of energy, its emitted either in the form of particles such as α-particles and β-particles (beta particles including the electron and the positron) or waves such as sunlight, X-rays and γ-rays. Radiation found everywhere around us and it comes from many different sources naturally or man-made sources. In this study a questionnaire was distributed to people working in the field of X-rays that used for a medical imaging (X-ray and CT-scan) to evaluate the extent of awareness and knowledge in estimate the damage of ionizing radiation as a result of wrong use. The questionnaire was distributed to medical clinics in Al-Harithiya in Baghdad, which it’s considered as one of the important areas in Iraq to attract and treat patients. It’s found that most of the commitment of radiography clinics by safety and security procedures. Most of the radiology clinics abide by most of the Iraqi Ministry of Health laws. However, some clinics did not implement some of the security and safety conditions

Metabolomics and Heart Diseases: From Basic to Clinical Approach

2019 ◽  
Vol 26 (1) ◽  
pp. 46-59 ◽  
Author(s):  
Ignasi Barba ◽  
Mireia Andrés ◽  
David Garcia-Dorado
Keyword(s):  
Clinical Practice ◽  
Cardiovascular Diseases ◽  
Heart Diseases ◽  
Medium Size ◽  
Clinical Approach ◽  
Full Spectrum ◽  
Main Research ◽  
Clinical Environments ◽  
The Many ◽  
Work Done

Background:The field of metabolomics has been steadily increasing in size for the last 15 years. Advances in analytical and statistical methods have allowed metabolomics to flourish in various areas of medicine. Cardiovascular diseases are some of the main research targets in metabolomics, due to their social and medical relevance, and also to the important role metabolic alterations play in their pathogenesis and evolution. </P><P> Metabolomics has been applied to the full spectrum of cardiovascular diseases: from patient risk stratification to myocardial infarction and heart failure. However - despite the many proof-ofconcept studies describing the applicability of metabolomics in the diagnosis, prognosis and treatment evaluation in cardiovascular diseases - it is not yet used in routine clinical practice. </P><P> Recently, large phenome centers have been established in clinical environments, and it is expected that they will provide definitive proof of the applicability of metabolomics in clinical practice. But there is also room for small and medium size centers to work on uncommon pathologies or to resolve specific but relevant clinical questions. </P><P> Objectives: In this review, we will introduce metabolomics, cover the metabolomic work done so far in the area of cardiovascular diseases.Conclusion:The cardiovascular field has been at the forefront of metabolomics application and it should lead the transfer to the clinic in the not so distant future.

scholarly journals Pair Production in AGN

1989 ◽  
Vol 134 ◽  
pp. 194-196
Author(s):  
C. Done ◽  
A. C. Fabian
Keyword(s):  
Pair Production ◽  
Compton Scattering ◽  
Energy Flux ◽  
Large Fraction ◽  
Small Region ◽  
X Rays ◽  
X Ray ◽  
Electron Positron ◽  
Γ Rays ◽  
Radiant Power

The X-ray luminosity and variability of many AGN are sufficiently extreme that any hard γ-rays produced in the source will collide with the X-rays and create electron-positron pairs, rather than escape. A small region where vast amounts of energy are produced, such as an AGN, is an ideal place to accelerate particles to relativistic energies and so produce γ-rays by Compton scattering. The observed X-ray spectra of AGN are hard and indicate that most of the luminosity is at the highest energies so that absorption of the γ-rays represents a large fraction of the energy flux, which can then be re-radiated at lower energies. Pairs can thus effectively reprocess much of the radiant power in an AGN.

scholarly journals The `quasi-mosaic' effect in crystals and its applications in modern physics

2015 ◽  
Vol 48 (4) ◽  
pp. 977-989 ◽  
Author(s):  
Riccardo Camattari ◽  
Vincenzo Guidi ◽  
Valerio Bellucci ◽  
Andrea Mazzolari
Keyword(s):  
Hadron Collider ◽  
Proton Synchrotron ◽  
X Rays ◽  
Super Proton Synchrotron ◽  
Charged Particle Beams ◽  
Modern Physics ◽  
Volume Reflection ◽  
Comprehensive Survey ◽  
Γ Rays ◽  
Crystallographic Planes

`Quasi-mosaicity' is an effect of anisotropy in crystals that permits one to obtain a curvature of internal crystallographic planes that would be flat otherwise. The term `quasi-mosaicity' was introduced by O. Sumbaev in 1957. The concept of `quasi-mosaicity' was then retrieved about ten years ago and was applied to steering of charged-particle beams at the Super Proton Synchrotron at CERN. Beams were deviated by exploiting channeling and volume reflection phenomena in curved crystals that show the `quasi-mosaic' effect. More recently, a crystal of this kind was installed in the Large Hadron Collider at CERN for beam collimation by the UA9 collaboration. Since 2011, another important application involving the `quasi-mosaic' effect has been the focalization of hard X-rays and soft γ-rays. In particular, the possibility of obtaining both high diffraction efficiency and the focalization of a diffracted beam has been proved, which cannot be obtained using traditional diffracting crystals. A comprehensive survey of the physical properties of `quasi-mosaicity' is reported here. Finally, experimental demonstrations for adjustable values of the `quasi-mosaic' curvature are provided.

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