Radiation Protection & Radiobiology Notes

Radiation Protection & Radiobiology Notes Human Biology • Human Response To Ionizing Radiation • Early Effects of Radiation: When response occurs within minutes or days after exposure. • Late Effects of Radiation: When response is not observed for many months or years after exposure. • Effects of fetal irradiation: Death, malformation, malignancy, diminished growth. • Composition of Human Body • Cell Theory: 85% of the body is hydrogen and oxygen. •  • Hydrogen: 60% • Oxygen: 25.7% • Carbon: 10.7% • Nitrogen: 2.4% •  • Molecular Composition • Water: 80% – A simple molecule. • Protein: 15% – A macromolecule. • Fat: 2% – A macromolecule. • Other: 3% • Tissues and Organs: (The most radiosensitive cells in the human body are Lymphocytes & Spermatogonia. . Fundamental Principles of Radiobiology • Law of Bergonie and Tribondeau • 1) Older cells are more radioresistant. • 2) Younger cells are more radiosensitive. • How these principles apply to radiation safety: The fetus is more radiosensitive to radiation than a child or adult. • Biologic Factors Affecting Radiosensitivity • Age: Humans are most sensitive before birth. • Gender: Females are less radiosensitive than males. . Molecular and Cellular Radiobiology • Irradiation of Macromolecules: (p.450) Follows a Linear, Non-threshold dose/response relationship. • Radiation Effects on DNA: DNA is the most radiosensitive macromolecule. • 1) Cell death • 2) Malignant disease • 3) Genetic damage • Radiolysis of Water: Indirect Effect. Most prevalent in humans. • We are mostly water: 80% Water • The breakdown of water by radiation is harmful. • Breakdown products, called free radicals, cause DNA damage. • DNA damage can cause somatic and genetic outcomes. Direct and Indirect Effect • Direct Effect: Radiation hits DNA causing cell damage. • Indirect Effect: 2 Step process The principle action of radiation on humans is the Indirect Effect. • 1) Radiation breaks down water molecules. • 2) Break down products (free radicals) damage DNA. Single-Target, Single-Hit Model • Poisson Distribution: A statistical law. If 100 rain drops fell on 100 squares, 63% will be wet, 37% will be dry. Early Effects of Radiation • Acute Radiation Lethality: X-ray beams are not large or intense enough to cause radiation lethality. • Early Effects: See a radiation response within a few days. • Local Tissue Damage:Requires a higher dose to produce a response. Results in tissue atrophy. • Skin: Erythema– a sunburn-like redness. SED50 (Skin Erythema Dose to affect 50% of pop.) at 600 Rad. • Gonads: Ovaries & Testes are very sensitive to radiation. Permanent sterility at 500 Rad. Late Effects of Radiation • Local Tissue Effects • Skin: High doses of radiation causes discolored and weathered appearance of skin....

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Desertification and the Soil

Name Course Number Instructor’s Name Due Date Which choice have you selected?  _________ . Instructions Select one of the two choices below and address all the topics listed under your choice with information you will learn from the provided resource.  Above list the section you have chosen. . You MUST paraphrase all content. Paraphrasing means putting all ideas in your own words. Review these resources on paraphrasing before beginning this assignment. • CTU Writing Center: Paraphrasing: https://careered.libguides.com/wscb/paraphrase • Video: The right and wrong ways to paraphrase: https://www.youtube.com/watch?v=SObGEcok06U . Choice 1: Desertification Visit the GreenFacts Initiative web-page on Desertification: https://www.greenfacts.org/en/desertification/index.htm#8 This webpage has 9 different sections discussing various aspects of Desertification. Using only this webpage, complete the following four activities putting your information directly in this document. 1. Read through all nine sections. 2. Select three sections, excluding sections 1 and 9, and summarize those sections in three separate paragraphs by paraphrasing the content. Include the title of the section you are summarizing above each paragraph. . Section Title:___________________________________________________ Section Summary: . Section Title:___________________________________________________ Section Summary: . . Section Title:___________________________________________________ Section Summary: . . 3. Summarize section 9, the conclusion, in one paragraph. . . . . 4. In one paragraph, discuss what you found most interesting in your chosen sections and how Desertification may impact your life. . . . . . Choice 2: Desertification and the Soil Watch this video, and address the following 4 topics. Each response must be at least one paragraph in length. http://www.geographyalltheway.com/myp/myp-biomes/desertification.htm . 1. Describe soil and its roles in agriculture. Address how long it takes for soil to form and the challenges of arid soil. . . 2. Describe how human activities cause desertification including desertification’s impacts on soil and the role of modern agriculture in causing Desertification. . . . . 2. Discuss who is impacted by desertification including which continents are impacted and the role of an increasing population. . . . . 3. Describe at least two approaches to reduce the problem of Desertification. . . . 4. Discuss what you found most interesting and how Desertification may impact your life. 2018 SCI201 U4 IP DesertificationWorksheet (1)...

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Overview China, Hong Kong, Taiwan

Overview China, Hong Kong, Taiwan Internet penetration of China, Hong Kong and Taiwan are 40%, 75% and 75% respectively. Although in absolute terms of number of internet users, China leads with 538 million users, followed by Taiwan with 17 million users and lastly Hong Kong with 5 million users.   In terms of Internet users and in terms of internet penetration, the following figures give us a clearer picture of previous statements.   As we can see, comparison between absolute number of internet users and internet penetration shows very different picture in Asia, especially when considering China, Hong Kong and Taiwan. The age demographics of internet users for these three countries is represented through the following figures.     Growth in internet penetration and mobile penetration in China has been phenomenal. The growth charts given below illustrate this over the years.   Internet penetration growth has been steady over the years, and there is no reason why the trend would not continue. Even though internet penetration is less than 50%, China has the most number internet users in the world. Theuse of internet on mobile also has grown quickly with double digit growth registered in 2008 and 2009. Even though the growth rate has been comparatively slow in 2010 to 2012, it still is a healthy growth. The figure below points out the major activities on mobile by Chinese mobile users. Clearly instant messaging is the major activity. This is the reason for success of many instant messaging applications in China such as Wechat (known as Weixin in China), Line and similar other apps. Mobile microblogging has always been very actively pursued by Chinses users. Even though previous applications such as Fanfaou, Jiwai and Digu were shut down by the government, the new platform Weibo has still attracted many users even with its censored design. According to Boston consulting group (BCG) the internet users in China by 2015 will be more than 700 million, a figure almost twice the combined size of US and Japanese internet user population. The average time spent by Chinese users on internet has also increased from 2.8 hours to 3.6 hours from 2008 to 2011. More than 50% of the internet users (most of which are students (63%) and young professionals (70%)), trust internet as a more reliable source of information than television and newspapers. A comparison of use of internet between Chinese and US...

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