Living with Our Sun's Ultraviolet Rays

ISBN-13: 9781461587460 / Angielski / Miękka / 2012 / 188 str.

Arthur C. Giese; Arthur C. Giese

Opis

Sunlight is part of everyday life and we accept it as good-and good it is in a number of ways. The sun is our source of warmth, and of the light by which we see. It is, in fact, the source of the energy with which life continues on earth. It furnishes energy for photosynthesis, and the pro ducts of photosynthesis constitute our food, building materials, and fuel. A steady state of balance and fine interrelationships exists between life on earth and all the forces and stresses in nature. This book will pin point the balance and relationships we share with sunlight. Our primary focus will be on the ultraviolet radiation of the sun, and on the ultraviolet photobiology of life on earth. This is the story of the effects of the sun's ultraviolet radiation, both good and bad, on all of us and all of life. We will explore the nature of the sun's ultraviolet radiation as it reaches the earth's surface today, and as it probably affected the earth in the distant past; and examine the effect of such radiation on all life, unicellular organisms as well as multicellular plants and animals. The effects of the sun's ultraviolet rays are primarily a result of their action upon cells, and secondarily, a result of their interactions between cells. The cell of a multicellular organism-man included-is also part of the tissue of an organ, and the organ is part of the whole organism."

Spis treści

1 The Sun, Sun Myths, and Sun Worship.- Sun and Sunlight.- • Sun Myths and Worship.- 2 Sunlight and Life.- The Ultraviolet Spectrum.- • The Primitive Atmosphere.- • Life and the Secondary Atmosphere.- • Evolution of Photosynthetic Cells and Development of an Ozone Layer 27.- • Life in the Aerobic Phase.- 3 Is Sunlight Good for You?.- Sunbathing.- • Bacteria and Ultraviolet Radiation.- • Skin Tuberculosis.- • Bone and Pulmonary Tuberculosis.- • Skin Diseases.- • Vitamin D and Rickets.- 4 How Ultraviolet Radiation Affects the Cell.- Radiation and Its Action.- • How Do Cells and Organisms Protect Themselves?.- • Mutation.- • Why Repair?.- 5 Sunburn.- Action Spectrum of Erythema.- • How the Skin Gets Sunburned.- • Tanning.- • Variation in Skin Sensitivity to Sunburn.- • Intracellular and Molecular Changes in Sunburn.- • Recovery from Sunburn.- • Protecting the Skin from Sunburn.- • Effects on the Eye.- 6 How Sunlight Ages Skin.- Pattern Changes.- • Melanocytes.- • Lubrication.- • Wrinkling.- • Blood Vessels.- • Connective Tissue.- • Comedones (Blackheads).- • Ultraviolet Action Spectra.- • Racial and Genetic Differences.- • Aging.- 7 Photosensitization of Cells.- Natural Photosensitizers.- • Photosensitization by Medications.- • Photosensitization in Diseased Conditions.- • Protection from Photosensitization.- 8 Sunlight and Cancer.- Animal Experiments.- • Sunburn Injury and Human Carcinogenesis.- • Relative Malignancy of Skin Cancers.- • Photosensitized Reactions to UV-A Rays.- 9 How Atmospheric Pollution Affects Sunlight and Life.- Natural Tropospheric Smog.- • Man-Made Tropospheric Smog.- • How Tropospheric Smog Reduces Antirachitic UV-B Rays.- • How the Nitrogen Cycle Regulates Stratospheric Ozone.- • Supersonic Transports.- • Atomic Bombs.- • Spray Can and Refrigerator Freons.- • What Are the Consequences?.