frontier lecture

FRONTIER LECTURE SERIES

Professor Anjali Mookerjee, who was professor and Dean of the School of Environmental Sciences at the Jawaharlal Nehru University, New Delhi, read Nuclear Physics, for her M.Sc. from Calcutta University and later obtained Ph.D in Biophysics from the Saha Institute of Nuclear Physics, Calcutta. She had her advanced training at the Biophysics Division of the Sloan Kettering Institute for Cancer Research, New York, and spent some time at the Rockefeller Institute, U.S.A. and later at the International Centre for Theoretical Physics, Trieste, Italy.
Prof. Anjali Mookerjee
She worked in the Division of Biophysics and also in the Division of Crystallography and Molecular Biology of the Saha Institute of Nuclear Physics. Since 1974 till her retirement in 1990, she had been associated with the School of Environmental Sciences, JNU, where she taught and guided research in Radiation and Molecular Biophysics. Since 1994 she is the Director (Hon) of the Sivatosh Mookerjee Science Centre, of Asutosh Mookerjee Memorial Institute, 77 Asutosh Mookerjee Road, Calcutta-25. She has published extensively in many international and National Research Journals and has several books to her credit, attended several International and National Symposia-seminars-conferences. She headed a very active research group in Biophysics the central theme of the work being the study of the effects of carcinogens, heavy metals and radiations on DNA and microorganisms. Before taking up her science career Prof. Mookerjee was trained as a Sanskrit scholar and has several research papers in the list of her publications.
RADIATIONS AND THE LIVING SYSTEM
(Abstract)
Radiation is form of energy which may be transferred from one body to another through empty space. Hot radiators emit radiation that we can fee (with our cold hands) in winter. Our Sun is the prime store-house of energy and all the energy and all the energy e receive from the Sun has been radiated in this way across 93 million miles of vacuum. Only a small part of this energy is in the from of light; most of the rest is radiant heat. Generally radiations are grouped into two categories: ionizing and non ionizing. In the ionizing category are X-rays,y-rays, particles etc. and in non-ionizing category are ultraviolet, visible light etc. The interaction of ionizing radiation with the human body, arising either from external sources outside the body or from internal sources of the body by radioactive substances, leads to biological effects which may show up as clinical symptoms. The nature and severity of these symptoms and the time at which they appear depend on the amount of radiation absorbed and the rate at which it is received. Radiation injuries can be divided into two classes i.e somatic effects in which it is received. Radiation injuries can be divided into two classes i.e somatic effects in which arise only in the offspring of irradiated person as a result of radiation damage to term cells in the reproductive organs. In 1896 Henri Bccquerel discovered that uranium salts spontaneously emitted some rays of unknown nature. As the material emitted radiation, it was called radioactive. These rays could pass through black paper and make impression on a photographic plate. This discovery fascinated the Curies-Maries and Pierre. They worked together and from uranium they made the famous discovery of radium-an element whose radiation was two million times stronger than that of uranium. On absorbing a quantum of U.V or visible light the whole of its energy is stored in the molecule, which can then undergo one of a number of different reactions. Some of which lead to chemical changes (molecular dissociations) and others to physical effects, e.g, fluorescence, heating etc. Action of light rays are much more selective than X (or y) rays. If U.V. light of 2600 A 0 passes through an equal mixture of nucleic acid and a serum protein, more that 90% of the energy is taken up by the nucleic acid, and less than 10 % by the protein. Using X-rays the same amount of energy is absorbed by the protein as by the nucleic acid. Although the sun in the potential source of all energy, cosmic radiation (which is composed of various types of radiation and energetic tiny particles) from outer space, which may affect ecosystems at higher altitude also contributes to it. Radiation Effects: In the field of radiological health, there is an interest in four direct overall effects of radiation on human beings. Biological changes caused by radiation in human being may be classified as: Acute effect caused by relatively large doses. Chronic effects on individuals caused by repeated intermediate level doses. Statistical effects on large populations resulting from repeated or sustained small doses. Genetic effects of small doses on large populations, the results of which would appear in the future generations. Chronic radiation Exposure: When irradiation is received at low dose rate over protracted periods of time repair processes act to change the observed signs of injury. A whole body dose of 100-200 rads received in a few hours or less, will produce changes in the peripheral blood count and transient intestinal damage. These signs of injury may not appear if the same dose is delivered over a period of several years. In the latter case the chance of developing leukemia or some other malignant process has increased. Some life shortening and genetic injury can also be expected. After the discovery of X-rays by Roentgen in 1895 and at the initial stage of diagnostic and therapeutic application, many workers suffered from cancerous lesions of the hands, leukemia etc. All early X-rays were relatively soft and so delivered the greatest dose at or near the surface of the body. Consequently all the early malignancies apparently originated in the skin. As medical uses of X-ray equipment and radium increased many physicians received injuries, which lead to death, usually from radiogenic cancer.

FRONTIER LECTURE SERIES

Professor Anjali Mookerjee, who was professor and Dean of the School of Environmental Sciences at the Jawaharlal Nehru University, New Delhi, read Nuclear Physics, for her M.Sc. from Calcutta University and later obtained Ph.D in Biophysics from the Saha Institute of Nuclear Physics, Calcutta. She had her advanced training at the Biophysics Division of the Sloan Kettering Institute for Cancer Research, New York, and spent some time at the Rockefeller Institute, U.S.A. and later at the International Centre for Theoretical Physics, Trieste, Italy.

Prof. Anjali Mookerjee

She worked in the Division of Biophysics and also in the Division of Crystallography and Molecular Biology of the Saha Institute of Nuclear Physics. Since 1974 till her retirement in 1990, she had been associated with the School of Environmental Sciences, JNU, where she taught and guided research in Radiation and Molecular Biophysics. Since 1994 she is the Director (Hon) of the Sivatosh Mookerjee Science Centre, of Asutosh Mookerjee Memorial Institute, 77 Asutosh Mookerjee Road, Calcutta-25. She has published extensively in many international and National Research Journals and has several books to her credit, attended several International and National Symposia-seminars-conferences. She headed a very active research group in Biophysics the central theme of the work being the study of the effects of carcinogens, heavy metals and radiations on DNA and microorganisms. Before taking up her science career Prof. Mookerjee was trained as a Sanskrit scholar and has several research papers in the list of her publications.

RADIATIONS AND THE LIVING SYSTEM

(Abstract)

Radiation is form of energy which may be transferred from one body to another through empty space. Hot radiators emit radiation that we can fee (with our cold hands) in winter.
Our Sun is the prime store-house of energy and all the energy and all the energy e receive from the Sun has been radiated in this way across 93 million miles of vacuum. Only a small part of this energy is in the from of light; most of the rest is radiant heat.
Generally radiations are grouped into two categories: ionizing and non ionizing. In the ionizing category are X-rays,y-rays, particles etc. and in non-ionizing category are ultraviolet, visible light etc. The interaction of ionizing radiation with the human body, arising either from external sources outside the body or from internal sources of the body by radioactive substances, leads to biological effects which may show up as clinical symptoms. The nature and severity of these symptoms and the time at which they appear depend on the amount of radiation absorbed and the rate at which it is received. Radiation injuries can be divided into two classes i.e somatic effects in which it is received. Radiation injuries can be divided into two classes i.e somatic effects in which arise only in the offspring of irradiated person as a result of radiation damage to term cells in the reproductive organs.
In 1896 Henri Bccquerel discovered that uranium salts spontaneously emitted some rays of unknown nature. As the material emitted radiation, it was called radioactive. These rays could pass through black paper and make impression on a photographic plate. This discovery fascinated the Curies-Maries and Pierre. They worked together and from uranium they made the famous discovery of radium-an element whose radiation was two million times stronger than that of uranium.
On absorbing a quantum of U.V or visible light the whole of its energy is stored in the molecule, which can then undergo one of a number of different reactions. Some of which lead to chemical changes (molecular dissociations) and others to physical effects, e.g, fluorescence, heating etc. Action of light rays are much more selective than X (or y) rays. If U.V. light of 2600 A 0 passes through an equal mixture of nucleic acid and a serum protein, more that 90% of the energy is taken up by the nucleic acid, and less than 10 % by the protein. Using X-rays the same amount of energy is absorbed by the protein as by the nucleic acid.
Although the sun in the potential source of all energy, cosmic radiation (which is composed of various types of radiation and energetic tiny particles) from outer space, which may affect ecosystems at higher altitude also contributes to it.
Radiation Effects: In the field of radiological health, there is an interest in four direct overall effects of radiation on human beings. Biological changes caused by radiation in human being may be classified as:
Acute effect caused by relatively large doses.
Chronic effects on individuals caused by repeated intermediate level doses.
Statistical effects on large populations resulting from repeated or sustained small doses.
Genetic effects of small doses on large populations, the results of which would appear in the future generations.
Chronic radiation Exposure: When irradiation is received at low dose rate over protracted periods of time repair processes act to change the observed signs of injury. A whole body dose of 100-200 rads received in a few hours or less, will produce changes in the peripheral blood count and transient intestinal damage. These signs of injury may not appear if the same dose is delivered over a period of several years. In the latter case the chance of developing leukemia or some other malignant process has increased. Some life shortening and genetic injury can also be expected.
After the discovery of X-rays by Roentgen in 1895 and at the initial stage of diagnostic and therapeutic application, many workers suffered from cancerous lesions of the hands, leukemia etc.
All early X-rays were relatively soft and so delivered the greatest dose at or near the surface of the body. Consequently all the early malignancies apparently originated in the skin.
As medical uses of X-ray equipment and radium increased many physicians received injuries, which lead to death, usually from radiogenic cancer.