A miniature version of the Star Trek "tractor beam" has been created by a team of scientists and could be used in medical testing.
In the popular science fiction show, a "tractor beam" was a method of using a beam of light to pull spaceships and other large objects.
Light manipulation techniques have existed since the 1970s but researchers said this is the first time a light beam has been used to draw objects towards the light source, albeit at a microscopic level.
A team of scientists from the University of St Andrews and the Institute of Scientific Instruments in the Czech Republic said they have found a way to generate a special optical field that efficiently reverses radiation pressure of light.
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The Metropolitan Police Federation, which set up the official JustGiving site, said it felt a "suitable amount" had been collected.
There is no evidence the Westminster attacker Khalid Masood was associated with so-called Islamic State or al Qaeda, the Met Police said.
Janet Ajao said in a statement: "I do not condone his actions nor support the beliefs he held that led to him committing this atrocity."