Tuesday 15 September 2015

Laser procedure can turn brown eyes blue

Either way, just 17% of the world's population has blue eyes.
For the majority of the world's population -- an estimated 80% - those elusive movie star eyes can usually only be obtained with the aid of colored contact lenses. But today there's a medical procedure that can permanently turn your brown eyes blue.
    Pioneered by Stroma Medical, the laser procedure works by eliminating the brown melanin that's present in the anterior layers of the iris.
    "The fundamental principle is that under every brown eye is a blue eye," Dr Gregg Homer told CNN, adding that there is no actual blue pigmentation in the eye.
    "The only difference between a brown eye and a blue eye is this very thin layer of pigment on the surface.

    Bright like the sky

    "If you take that pigment away, then the light can enter the stroma -- the little fibers that look like bicycle spokes in a light eye - and when the light scatters it only reflects back the shortest wavelengths and that's the blue end of the spectrum."
    He said the effect is similar to the Rayleigh scattering of sunlight in the sky -- the physics that makes our sky appear blue.
    The company says it has developed a laser treatment that disrupts the layer of pigment, causing the body to begin removing the tissue naturally. While the procedure takes all of 20 seconds, the blue eyes lurking underneath do not emerge for several weeks.
    He said that Stroma Medical wanted to develop a procedure that was safer, cheaper and more convenient than any of the alternatives on the market.

    Low intensity laser

    While it has yet to get the green light from regulatory bodies in the United States, the company's medical board has said that preliminary studies show the surgery is safe.
    So far, just 17 patients in Mexico and 20 in Costa Rica have undergone the treatment.
    "It's difficult to work out a way to injure someone with this laser because the energy is so low," he said.
    The laser treats only the iris and does not enter the pupil or treat any portion of the inside of the eye where the nerves affecting the vision are located.
    The company is still in the fundraising stage but hopes to have completed clinical trials within several years.
    And the cost of turning your brown eyes blue?
    Dr Homer says Stroma Medical would charge around $5,000 (£3,120) for the procedure.

    Industry skepticism

    Industry reaction to the process has been muted. Ophthalmologists who deal with people's eyes, Homer concedes, have every right to be skeptical for the simple fact they are dealing with one of the most sensitive organs in the human body.
    Saj Khan, an ophthalmologist at the London Eye Hospital, told CNN the treatment raised some red flags.
    'The main concern with any procedure that involves releasing pigment inside the eye is that the pigment can clog up the normal drainage channels which can in turn cause the pressure inside the eye to go up," he said.
    "If that happens significantly enough, for long enough, it's how patients develop glaucoma."
    He said that while Stroma Medical claims that the particles released by the process are too fine to cause glaucoma -- and that any complications were likely to be short-term and easily remedied - a risk still remains.
    "Theory has some sense to it, but without seeing long-term outcomes and without seeing patients that have been treated in this way I wouldn't commit myself to it," Khan said.

    Blue skies for blue eyes

    In the meantime, Homer says there are no shortage of potential customers wanting to have the irreversible procedure.
    "It's not a goal of our company to promote blue eyes," he said. "From my experience what most people are after is the translucence of the blue eye rather than the color of the blue eye.
    "The people who seem most vigilant about pursuing this always have a story about being young and in the presence of a sibling or a friend who had light eyes and the friend is being told how beautiful their eyes are and it sticks with them.
    "That seems to be something they've carried around with them. Would it be better for them to get over it? Probably.
    "All your problems don't go away because you've changed your eye color but I do believe that people like to express themselves a certain way and it's nice when they have the freedom to do that."

    Tuesday 8 September 2015

    Mobile phone tracking crackdown in US

    Stingray
    Image captionThe Stingray is a powerful mobile phone surveillance tool
    The US government is cracking down on the way law enforcement agencies use technology to track criminals.
    Fake mobile phone towers, often called Stingrays, offer valuable information about suspects but also collect vast amounts of data from innocent passers-by.
    From now on, agencies will need to obtain a search warrant to use such devices.
    The US Department of Justice said it wanted to protect citizens' privacy.
    "Cell-site simulator technology has been instrumental in aiding law enforcement in a broad array of investigations, including kidnappings, fugitive investigations and complicated narcotic cases," Deputy Attorney General Sally Quillian Yates said in a statement.
    "This new policy ensures our protocols for this technology are consistent, well-managed and respectful of individuals' privacy and civil liberties," she added.
    The policy, which takes effect immediately, applies to the Federal Bureau of Investigation (FBI) the Bureau of Alcohol, Tobacco and Firearms, the Drug Enforcement Administration (DEA) and the United States Marshals Service.
    It does not apply to local police forces although some states, including Washington, Virginia, Minnesota and Utah, have already imposed a warrant requirement.

    Shrouded in secrecy

    The portable boxes can be used to determine the location of a suspect and can also intercept calls and text messages.
    The American Civil Liberties Union (ACLU) estimates that up to 53 agencies in 21 states own Stingrays.
    It has long complained that the use of the technology is shrouded in secrecy, making it hard to accurately pinpoint how widely they are used.
    ACLU lawyers welcomed the move but said that more could be done to extend the policy to all law enforcement agencies.
    It also pointed out that there were several loopholes in the legislation that allowed law enforcers to use the technology without a warrant.
    Earlier this year, German security firm GSMK Cryptophone claimed to have uncovered evidence of at least 20 instances of the use of cell-site simulators in the UK.
    The Metropolitan Police Service refused to confirm or deny it was using them.

    Friday 4 September 2015

    CD Burning: Take it to the Edge

    Introduction

    The music that we listen to, the movies we watch, and the video games we play are often stored on CDs. A CD is a way of storing data, or information, by using a laser to etch the data into a long groove, called a track. The data in the track is etched as a long series of tiny bumps that are scanned by a laser in your CD or DVD player. Each CD has one long spiral track of data that circles from the inside of the disc to the outer edges. Each tiny data track is only about 0.5 microns wide, with a spacing of 1.6 microns between each track. A micron is a millionth of a meter, so each individual track is much too small to be seen by the naked eye!


    CD Spirals
    A CD has a long, spiraled data track. If you were to unwind this track, it would extend out 3.5 miles (5 km). (Harris, 2006)
    If you have a CD burner, you can store data by using special CDs called CD-Recordable discs, or CD-R's. These special discs don't have any bumps in the data track. Instead they use a series of light and dark spots which are "burned" into the track when the laser of the CD burner shines on the track and reacts with a special light-sensitive dye inside the disc. When the disc is empty the dye is clear, but when you heat the dye with concentrated light from the laser, the dye darkens. By blinking the laser on and off along the track, the CD burner etches a series of light and dark spots which create a digital pattern that a standard CD player can read.
    In this experiment you will take advantage of the change in the light-sensitive dye inside the CD-R to measure how much data has been burned. After marking the border between used and unused parts of the disc, you will use a ruler to measure how much space the data uses. What will happen to the amount of free disc space as more data is burned to a disc?

    Terms and Concepts

    To do this type of experiment you should know what the following terms mean. Have an adult help you search the Internet, or take you to your local library to find out more!
    • Compact Disc - Recordable (CD-R)
    • CD burner
    • data
    • file size (MB)
    Questions
    • How much information can be stored on a CD?
    • Can you see the information stored on a CD?
    • How can the amount of information on a CD be measured?

    Materials and Equipment

    • computer
    • CD burner (internal or external)
    • 8 blank CD-R discs
    • a photo, music file, or folder about 100 MB in size
    • permanent marker
    • metric ruler

    Experimental Procedure

    1. In this experiment you will need to use a CD burner to write data onto a CD-R disc. First, check with a parent to make sure you have access to a CD burner. It can either be internal (inside your computer) or external (something you will need to connect with a cable). Have your parents show you how to properly use the device.
    2. CD-burners use software to help you burn data onto the disc. Familiarize yourself with the software that your parents use to burn CDs. Make sure you know how to:
      • load files onto the blank CD,
      • find the allocated (used) disc space,
      • find the available (unused) disc space,
      • initiate and complete the burn.
    3. You will need some data to burn onto your CD. Good sources of data are photos and music. Try to find a file that is about 100MB. It is a good idea to save a separate copy of this file, because you will be writing on your CD later (and probably spoiling it for reading on your computer). So be sure that the file you choose is either unimportant or is saved somewhere on the computer else.
    4. Once you find the file you want to use, put it in a new folder on your desktop entitled, "CD Burn Experiment" so that you can find it easily.
    5. Next, you need to make a data table to record your results:


      TrialUsed Disc Space (MB)Unused Disc Space (MB)Distance From the Center (cm)
      #1   
      #2   
      #3   

    6. Place your first CD-R into the burner, place one copy of your file on the disc and burn. Write down the amount of used and unused disc space in your data table.
    7. After the burn is complete, write "Trial #1" on the front of the CD with a permanent marker.
    8. Turn the CD-R over to the shiny side. While tilting the CD-R from side to side, try and locate a fine line that encircles the disc. The inner side of the line will appear slightly dull compared to the outer side of the line. This line is at the edge of the laser etched portion of the data you have written on the disc, which appears dull.

      Used and free space on a burned CD
      In this photo, an arrow marks the border between the used and free disc space of a CD-R after being burned.
    9. When you see it, place a dot on the line with a permanent marker. Measure the distance from the center of the CD-R to the dot you have marked. Write the data in your data table.
    10. Repeat steps 6–9 with the next CD-R, but this time put two copies of your file on the disc (which should be about 200 MB). When complete, label the disc "Trial #2" and find the line, mark and measure as before.
    11. Continue to add one more file each time, until you have a total of 6 or seven trials. This will depend upon the size of the file you use (< or > 100 MB) and the size of your CD-R (74 or 80 min).
    12. What happens to the location of the line as more data is stored onto the disc?
    13. Make a graph of your results. Does the distance from the center of the disc increase or decrease as more data is added? Is the amount of increase in distance the same each time? Why or why not?