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Looking for UV LEDs ...tia SAL

Discussion in 'Misc Electronics' started by sal, Aug 1, 2005.

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  1. sal

    sal Guest

    Greetings All,

    I'm looking for an ultraviolet LED that is around 254 NM Wavelength I'm
    trying a different approach to killing bacteria that cause cavities. Using
    UV light instead of going to a dentist that uses a drill.


    "(UV) Lamps disinfect water for residential and commercial applications.
    These lamps create light at 254 NM wavelength, this wavelength kills all
    bacteria, viruses, molds, algae, and yeast in your water supply"

    TIA
     
  2. There aren't any LEDs in production yet producing germicidal UV. Also,
    expect any earlier model such LEDs to not irradiate the whole inside of
    your mouth to kill bacteria all over within an hour - germicidal lamps
    that resemble fluorescent lamps are better for this and will be even when
    such LEDs do become available.

    More considerations:

    1. Sufficient germicidal UV to kill bacteria kills the top layer to few
    layers of cells of all exposed tissue in your mouth that has live cells
    exposed to the UV.

    2. Human cells damaged but not killed by UV may have genetic
    damage that could cause cancer.

    3. Bacteria in locations shaded from the UV survive and could replenish
    the plaque in your mouth in less than a day. Bacteria under the gumline
    are shaded from germicidal UV.

    I recommend brushing and flossing, brushing with fluoride-containing
    toothpaste, drinking fluoridated water, and getting the tooth surface
    treatments that dentists normally provide.

    With usual good cavity prevention tactics, the main hazard of plaque is
    periodontal disease - also mitigated by brushing and flossing.

    - Don Klipstein ()
     
  3. Don Bruder

    Don Bruder Guest

    You're out of luck, bub... Sorry...


    Yeah... At mongo-huge wattages, in specially designed (*NO* shadows or
    hidden nooks and crannies - Does your mouth fit that description?)
    containers, where it sits for an amount of time you'd consider
    absolutely ridiculous if you had to do it on a daily(or even every other
    day) basis. Also, water, glass, and metal are immune to the genetic
    damage (AKA "cancer-causing") effects of UV exposure. I *VERY* highly
    doubt you can say that for the inside of your mouth... I imagine it'd
    probably be less than a year before you sprouted your first precancerous
    lesion, assuming your whole damn HEAD didn't simply explode into one
    giant tumor.

    Then there's the fact that there is no such LED currently being made,
    and there isn't likely to be one for quite some time.

    In other words, forget it. Your idea has more holes in it than a screen
    door. Brush, floss, and see Dr. Drill-n-fill as needed, and leave the UV
    anti-bacterial treatments to the water plants, where they actually have
    a chance at working.
     
  4. JANA

    JANA Guest

    I don't know of any UV LEDs' that work in the 254 nm region for
    sterilization.

    As for exposing the inside of your mouth to UV radiation that can kill
    bacteria, this can pose a danger for cell damage to the gums, and to the
    other tissues in the mouth. This can pose condition where by cancer cells
    can be easily formed. The exposer would have to be for a determined period
    of time, depending on the strength of the UV radiation, and the distance
    from the emission source.

    Nothing will beat good dental habits, such as proper flossing, and brushing
    of the teeth to keep up with proper hygiene.

    As for killing bacteria in the mouth, there are some very effective mouth
    washes. They in themselves have other side effects that can be hard on the
    mouth tissues and gums. They also kill friendly bacteria that is good to
    have for the system's self defence.

    If the plaque on the teeth is not properly removed, even though the bacteria
    of its makeup is destroyed, it will eventually harden, and thus cause a
    greater frequency of dental cleanings to be done. This plaque puts a coating
    on the teeth that can be acid in nature, and thus cause the teeth to be
    eaten away. The plaque can sometimes form below the gum line, and thus cause
    gum problems, which can lead to more serious problems. Cavities below the
    gum line are serious, and will usually require gum surgery, to be able to
    fix the tooth.

    With proper dental care, the chance of having cavities is much less, than
    without. See your dentist regularly for proper cleanings, and examinations.
    This way, you should be able to avoid problems.

    Brush your teeth often, and brush and floss every day before going to sleep.
    After your teeth are cleaned, never eat, or drink anything with substance,
    other than water. Never get up in the middle of the night to have a snack,
    and not re-clean your teeth. Eating within 2 hours of sleeping is unhealthy,
    and will promote a greater degree of cholesterol accumulation in the
    arteries. Snacking late in the evening, or during the night is very
    unhealthy. When we are sleeping, our liver tends to makes more cholesterol.

    When you get up in the morning, it is important to brush your teeth. The
    morning accumulation of bacteria in the mouth, plays a great part in making
    plaque accumulation on the teeth. The front lower teeth are most effected.

    Brush your teeth right after you finish breakfast. This is actually best for
    after each meal.


    --

    JANA
    _____


    Greetings All,

    I'm looking for an ultraviolet LED that is around 254 NM Wavelength I'm
    trying a different approach to killing bacteria that cause cavities. Using
    UV light instead of going to a dentist that uses a drill.


    "(UV) Lamps disinfect water for residential and commercial applications.
    These lamps create light at 254 NM wavelength, this wavelength kills all
    bacteria, viruses, molds, algae, and yeast in your water supply"

    TIA
     
  5. redbelly

    redbelly Guest

    I'm not aware of LED's available in that wavelength, the shortest
    wavelength I know about are in the 370-390 nm range.

    But, I'm not sure this would be a good approach to what you want to do.
    This wavelength is particularly damaging to skin. Also, what about
    the bacteria located under the gums, where a uv source would not reach?

    Mark
     
  6. Bret Cannon

    Bret Cannon Guest

    Look up the SUVOS program funded by DARPA. Its aim was to develop UV LEDs
    for various biological sensing applications. As I recall 350 nm and 280 nm
    were their target wavelengths because each wavelength is good for exciting a
    certain class of biological molecules. I don't think that a wavelength as
    short as 254 nm was thought possible, but they made a lot of progress.

    Bret Cannon
     
  7. Guest

    I'm not sure I'd like 254nm bouncing around inside my mouth.

    Jon
     
  8. The UV needs to be short wavelengths in order to sterilize and have
    enough energy to dissociate oxygen molecules into ozone. You may not be
    able to get those short wavelengths from a LED. But it should be easy
    to do it with mercury arc.

    I remember when I was a kid, they had UV lamps inside the dryer. When
    it was done drying a load of clothes, I could smell ozone when they were
    taken out. The bulb was similar to a regular incandescent light bulb,
    but it had a dark coating, and there was mercury and mercury vapor
    inside. Somehow, after the filament heated up for awhile, the arc would
    go across the mercury vapor. It might have been a bimetallic strip that
    opened the filament after a time, so that there was no incandescence,
    only the mercury arc.

    Note, I said that there was the smell of ozone. Putting UV rays into
    your mouth might create ozone, and you might have adverse health effects
    from it. I know that it's not good to breathe ozone in high
    concentrations, even tho it's all around us in the air pollution.
     
  9. You're out of luck, bub... Sorry...


    Yeah... At mongo-huge wattages, in specially designed (*NO* shadows or
    hidden nooks and crannies - Does your mouth fit that description?)
    containers, where it sits for an amount of time you'd consider
    absolutely ridiculous if you had to do it on a daily(or even every other
    day) basis. Also, water, glass, and metal are immune to the genetic
    damage (AKA "cancer-causing") effects of UV exposure. I *VERY* highly
    doubt you can say that for the inside of your mouth... I imagine it'd
    probably be less than a year before you sprouted your first precancerous
    lesion, assuming your whole damn HEAD didn't simply explode into one
    giant tumor.

    Then there's the fact that there is no such LED currently being made,
    and there isn't likely to be one for quite some time.

    In other words, forget it. Your idea has more holes in it than a screen
    door. Brush, floss, and see Dr. Drill-n-fill as needed, and leave the UV
    anti-bacterial treatments to the water plants, where they actually have
    a chance at working.[/QUOTE]

    I love your not so prosaic wit, Don, especially the 'screen door' bit.
    Someone mentioned that germicidal bulbs are too big to fit in your
    mouth, but it would be easy to make a small set of electrodes that could
    produce an arc with a lot of short wave UV in it. Of course there might
    be the problem of heat, and the ill effects you mention above. So it's
    probably a Really Bad Idea(TM).
     
  10. Gawd! This person sounds like a mother, a dentist, a Dr., and a
    toothpaste commercial all wrapped up into one! Next thing you know,
    s/h/it will be telling us that it's bad to breathe the pollution, so
    stop breathing! :-/
     
  11. Here's an exerpt from one of the docs I dug up with a SUVOS search.
    Some inetesting info about LEDs saving electricity, fuel, etc.




    This is the html version of the file
    http://minerals.usgs.gov/minerals/pubs/commodity/gallium/gallimyb03.pdf.
    G o o g l e automatically generates html versions of documents as we
    crawl the web.
    To link to or bookmark this page, use the following url:
    http://www.google.com/search?q=cache:nECHu3lAQKsJ:minerals.usgs.gov/mine
    rals/pubs/commodity/gallium/gallimyb03.pdf+SUVOS+program+funded+by+DARPA
    &hl=en

    Google is not affiliated with the authors of this page nor responsible
    for its content.
    The U.S. Department of Energy released two studies that analyzed and
    estimated energy savings of solid-state lighting (mainly
    LEDs). One study estimated the energy savings potential if solid-state
    lighting can achieve certain price and performance criteria.
    The report considered two scenarios—one where the technology receives a
    moderate national investment of $50 million per year and
    an accelerated scenario based on an investment of $100 million per year.
    Under the moderate investment scenario, in 2025, the energy
    savings associated with solid-state lighting could total approximately
    114 terawatthours (TWh) or the equivalent annual electrical
    output of about 14 large powerplants. Under the accelerated investment
    scenario, in 2025, the total energy savings could be about 326
    TWh, representing the output of more than 40 large powerplants (Navigant
    Consulting Inc., 2003b§1).
    ....


    The second study that looked at LED use in niche applications concluded
    that LED traffic signals use only 10% of the electricity
    consumed by the incandescent lamps they replace, and they last much
    longer, allowing for additional savings through reduced
    maintenance costs. Exit signs were identified as another important niche
    application, where an estimated 80% of U.S. exit signs now
    use LEDs. LEDs also have made inroads into mobile applications, such as
    brake and signal lights on automobiles, buses, and trucks.
    To date, 41 million gallons per year of gasoline and 142 million gallons
    per year of diesel fuel have been saved because of LED use on
    these vehicles. (Fuel savings were calculated based on the lower
    accessory load on the engine.) If all automobiles, buses, and trucks
    were to convert to LED lighting, 1.4 billion gallons per year of
    gasoline and 1.1 billion gallons per year of diesel fuel could be saved
    (Navigant Consulting Inc., 2003a§).
     
  12. Mike S.

    Mike S. Guest

    Anything designed for disinfection will cause as much damage to the inside
    of your mouth as to the germs you're trying to kill. That's the difference
    between DISINFECTANTS (used on non-living objects) and ANTIBIOTICS (used
    on living things). Ask your dentist to prescribe PERIDEX.
     
  13. I remember those "dryer bulbs".

    They have a filament and require a ballast to limit current. A 40 watt
    120V incandescent will work as a ballast.
    When the voltage across the filament gets much past about 12 volts, an
    arc forms across the ends of the filament. The voltage across this arc is
    about 11 volts. These lamps have a nominal wattage of 4 watts.

    These lamps produced both the 253.7 nm main germicidal wavelength of
    mercury and the ozone-forming wavelength of 184.9 nm (which is also
    germicidal).
    Some other germicidal low pressure mercury lamps have output of 184.9 nm
    minimized to minimize ozone production.

    As for how bad to breathe is the ozone from a lamp that generates ozone?
    If you can smell it, the concentration is higher than that in summertime
    urban smog.

    - Don Klipstein ()
     
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