Презентация Ultraviolet radiation (UV) онлайн
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- Тип файла:ppt / pptx (powerpoint)
- Всего слайдов:36 слайдов
- Для класса:1,2,3,4,5,6,7,8,9,10,11
- Размер файла:680.83 kB
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- Автор:неизвестен
Слайды и текст к этой презентации:
№1 слайд
Содержание слайда: Ultraviolet radiation
(UV)
№2 слайд
Содержание слайда: Research questions:
1.What is ultraviolet?
2. What are its mechanisms?
3. How does it influence flora & fauna? Inanimate objects?
4. How is it presently applied by human?
№3 слайд
Содержание слайда:
№4 слайд
Содержание слайда: Meet, ultraviolet!
The radiation of the Sun contains a few types of emitting, which differ from one another in the wavelength. The intermediate radiation, or ultraviolet radiation, is believed to have both benign and pernicious impact on the health of living things. It is able to pass through the atmosphere even in cold and cloudy weather.
№5 слайд
Содержание слайда: Let's consider the most common types of UV:
Let's consider the most common types of UV:
UVA (400-315nm) rays have a relatively long wave length and represent close to 95% of the UV rays that make it to the Earth’s surface .
UVB (315-280nm) have a medium wave length. Only its part passes through the atmosphere.
№6 слайд
Содержание слайда: UVA
UVA rays age skin cells and can damage their DNA. These rays are linked to long-term skin damage such as wrinkles, but they are also thought to play a role in some skin cancers. Most tanning beds give off large amounts of UVA, which has been found to increase skin cancer risk.
№7 слайд
Содержание слайда: UVB
UVB rays have slightly more energy than UVA rays. They can damage skin cells’ DNA directly, and are the main rays that cause sunburns. They are also thought to cause most skin cancers.
№8 слайд
Содержание слайда: UVC
UVC rays have more energy than the other types of UV rays, but they don’t get through our atmosphere and are not in sunlight. They are not normally a cause of skin cancer.
№9 слайд
Содержание слайда: What influence do UV rays have on the condition of living things?
№10 слайд
Содержание слайда: Photosynthesis
UV radiation however causes production of reactive oxygen species (ROS) which may cause various type of damage to biomolecules. Extreme damage leads to cell death/chlorosis/necrosis and obviously a loss of photosynthetic process.
№11 слайд
Содержание слайда:
№12 слайд
Содержание слайда: Health effects
The ultraviolet radiation in sunlight has both positive and negative health effects, as it is both a principal source of vitamin D3 and a mutagen.
№13 слайд
Содержание слайда: Beneficial outcomes
The benefits of UV can outweigh manageable risks. The human body needs some UV radiation in order for one to maintain adequate level of viability.
№14 слайд
Содержание слайда: Vitamin D
Vitamin D
Reasonable exposure to ultraviolet radiation from the sun can be a good source of vitamin D. Getting enough vitamin D can help stave off autoimmune diseases, cardiovascular disease, many types of cancer, dementia, types 1 and 2 diabetes mellitus, and respiratory tract infections.
№15 слайд
Содержание слайда: Serotonin
Serotonin
Vitamin D promotes the creation of serotonin. The production of serotonin is in direct proportion to the degree of bright sunlight the body receives. Serotonin is a monoamine neurotransmitter that is thought to provide sensations of happiness, well being and serenity to human beings.
№16 слайд
Содержание слайда: Melanin
Melanin
The amount of the brown pigment melanin in the skin increases after exposure to UV radiation at moderate levels depending on skin type. Melanin is an excellent photoprotectant that absorbs both UVB and UVA radiation and dissipates the energy as harmless heat, protecting the skin against DNA damage.
№17 слайд
Содержание слайда: Effects on eyes
Effects on eyes
Significant daily exposure to bright light may be necessary for children to avoid myopia (nearsightedness).
№18 слайд
Содержание слайда: Harmful effects
Excessive exposure to UV radiation can result in acute and chronic harmful effects on the skin, eye, immune system and DNA.
№19 слайд
Содержание слайда: Skin damage
All bands of UV radiation damage collagen fibers and accelerate aging of the skin. Both UVA and UVB destroy vitamin A in skin, which may cause further damage. UVB radiation can cause direct DNA damage.
№20 слайд
Содержание слайда: Eye damage
Prolonged optical exposure to sunlight, especially intense ultraviolet light, may be linked to cortical cataracts. Short-term over-exposure can cause snow blindness, which is analogous to sunburn of the cornea, or can cause solar retinopathy, which is long-lasting retinal damage and vision impairment from sungazing.
№21 слайд
Содержание слайда: UV skin protection
SPF stands for sun protection factor. Sunscreens are classified by an SPF number which refers to their ability to deflect UVB rays. The SPF rating is calculated by comparing the amount of time needed to burn sunscreen-protected skin vs. unprotected skin.
№22 слайд
Содержание слайда: Classic vs. Mineral: Which is Which?
Classic and Mineral Sunscreens are differentiated by their active sun protection ingredients. Classic sunscreens use chemical active ingredients designed to absorb and dissipate UVA/UVB rays, while Mineral sunscreens use mineral active ingredients such as Titanium Dioxide and Zinc Oxide to scatter and reflect UVA/UVB rays.
№23 слайд
Содержание слайда: The effect of classic suntans is based on chemical reactions by swallowing sun radiation and mineral ones create a protective layer on the skin surface.
The effect of classic suntans is based on chemical reactions by swallowing sun radiation and mineral ones create a protective layer on the skin surface.
№24 слайд
Содержание слайда: UV eye protection
To decrease the risk of developing eye-related diseases, it may be wise to wear sunglasses when outdoors, even on overcast days.
№25 слайд
Содержание слайда: But what about inanimate objects?
№26 слайд
Содержание слайда: Degradation of polymers, pigments and dyes
Many natural and synthetic polymers are attacked by ultraviolet radiation, and products using these materials may crack or disintegrate if they are not UV-stable.
№27 слайд
Содержание слайда:
№28 слайд
Содержание слайда: Applications
Because of its ability to cause chemical reactions and excite fluorescence in materials, ultraviolet radiation has a number of applications.
№29 слайд
Содержание слайда: Photography
Photography by reflected ultraviolet radiation is useful for medical, scientific, and forensic investigations, in applications as widespread as detecting bruising of skin, alterations of documents, or restoration work on paintings.
№30 слайд
Содержание слайда: Analytic uses
UV is an investigative tool at the crime scene helpful in locating and identifying bodily fluids. Other applications include the authentication of various collectibles and art, and detecting counterfeit currency.
№31 слайд
Содержание слайда: Air purification
Using a catalytic chemical reaction from titanium dioxide and UVC exposure, oxidation of organic matter converts pathogens, pollens, and mold spores into harmless inert byproducts.
№32 слайд
Содержание слайда: Sterilization & disinfection
Ultraviolet lamps are used to sterilize workspaces and tools used in biology laboratories and medical facilities.
Solar water disinfection has been researched for cheaply treating contaminated water using natural sunlight. The UV-A radiation and increased water temperature kill organisms in the water.
№33 слайд
Содержание слайда: Insects trapping
Ultraviolet traps called bug zappers are used to eliminate various small flying insects. They are attracted to the UV and are killed using an electric shock, or trapped once they come into contact with the device. Different designs of ultraviolet radiation traps are also used by entomologists for collecting nocturnal insects during faunistic survey studies.
№34 слайд
Содержание слайда: Skin conditions
Skin conditions
UV rays also treat certain skin conditions. Modern phototherapy has been used to successfully treat rickets, psoriasis, eczema, jaundice, vitiligo, atopic dermatitis, and localized scleroderma.
№35 слайд
Содержание слайда: Summary findings
UV occurs to be the one of nature factors which we only have the opportunity to receive with beneficial and harmful sides bound together.
The effect of the ultraviolet can be used and turned into the tool for the human’s wellbeing.
№36 слайд
Содержание слайда: Sources
http://www.coolasuncare.com/sun-science/
https://www.google.ru/amp/www.sofeminine.co.uk/skin-care/uv-rays-how-do-they-work-s565165.html.amp
https://www.loc.gov/rr/scitech/mysteries/colors.html
https://en.wikipedia.org/wiki/Ultraviolet?wprov=sfsi1
https://www.cancer.org/cancer/skin-cancer/prevention-and-early-detection/what-is-uv-radiation.html
https://www.quora.com/How-does-UV-radiation-affect-photosynthesis-in-plants
http://www.sciencedirect.com/science/article/pii/S0098847209001580
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