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Bubbles in the body could save the lives of people suffering from malignant tumours if findings by scientists at the University of Michigan lead to a new way of cutting off the blood supply of cancer cells.

The usefulness of bubbles is usually confined to the bath or keeping the kids amused but the researchers are working on technology that will use gas bubbles like corks, blocking the flow of blood to tumours - starving them of oxygen and killing them in the process.

Blocking blood flow is one of the techniques doctors use to treat tumours - known as embolisation. Typically, the blood vessel leading to the growth is blocked using a solid “cork”, or emboli, made from a blood clot or a gel.

But it is difficult to control exactly where the emboli - which is delivered by catheter - is placed, meaning that it can block other vessels, causing damage to healthy surrounding tissues or necessitating very invasive procedures.

According to the Michigan team - led by Joseph Bull, assistant professor of biomedical engineering, and Brian Fowlkes, an associate professor in the Department of Radiology in the university medical school - the gas bubble method allows doctors to control exactly where the bubble is formed by using a focused high intensity ultrasound. This makes for a much greater degree of control of the emboli, minimising the impact on surrounding tissues.

There are two stages to the procedure. A stream of encapsulated superheated perfluorocarbon liquid droplets - small enough so they don’t lodge in the vessels - is injected intravenously into the body.

Doctors follow the progress of the droplets with standard ultrasound and once they reach their destination, doctors blast them with high intensity ultrasound. The ultrasound “acts like a pin popping a water balloon” and the perfluorocarbon expands into a gas bubble with a volume about 125 times larger than the droplet. The bubble shapes to size of the vessel, forming a “sausage-shaped” bubble which acts as a cork.

The researchers say two or three doses of bubbles should be enough to completely stanch the blood flow, killing the tumour. They add that the technology could be particularly effective at treating renal cancer and the most common form of liver cancer.

Printed plane

Lockheed Martin have taken an unusual approach to keeping down the costs of building unmanned aircraft, by using “printed parts” rather than traditional machine-tooled components, according to a story on New Scientist.com.

Much of the Polecat unmanned aerial vehicle (UAV), revealed to the public at this year’s Farnborough airshow, was constructed using 3D rapid prototyping or 3D printing, the process of generating an object directly from its digital representation in a computer-aided design (CAD) system.

3D designs for individual parts of the Polecat were fed from a CAD system to a chamber known as a 3D printer. Inside the printer, two computer-controlled laser beams fuse polymers or metal powder layer by layer into complex 3D shapes.

Although the technique is typically used in industry to make prototype parts for testing, the technology has improved so much that 3D printing can now be used to make working components.

The developers at Lockheed’s “Skunk Works” facility in California, who also designed the U2 high-altitude spyplane and the F117 stealth fighter, say that much of the Polecat was made from composite materials using rapid prototyping including all of its airframe.

The main benefit of this process is to reduced time to produce a part, which in turn speeds up the entire development process. UAV’s are becoming more and more sophisticated making them almost as expensive as piloted aircraft, but at the same time they tend to crash more. Lockheed hope the Polecat will point the way to a more affordable and rapid way of constructing unmanned aircraft.

Medication from fish slime

With superbugs running rampant through hospitals as they become more resistant to antibiotics, the search is on for alternative methods to beat hospital bacteria.

And the hunt has lead researchers into strange plaices - pun intended!

Trude Tvete, a chemical engineer of Nord-Trondelag University in Norway, has discovered that the slime that covers the flat-fish plaice contains a substance that kills staphylococcus, a category of bacteria that can cause boils, food and blood poisoning, septicemia and other serious infections.

Staphylococci are generally partly or wholly resistant to antibiotic action, raising serious problems in the treatment and control of infections. This is especially the case in hospitals where they spread quickly, putting the young, old and infirm at risk.

Ms Tvete cleaned and separated the slime into its component parts, identifying a protein deep within its skin that has the greatest effect against staphylococcus.

The protein, which is used in the fish’s immune system, was shown to be “very efficient” at killing the bacteria.

Ms Tvete thinks the substance could be used as the basis of human medication. Bacteria-killing substances from other animals such as mammals have been investigated, but those in fish are built up in a different way and therefore can overcome bacteria that have become resistant to antibiotics. The plaice also has the potential to be fish-farmed, meaning that potential bacteria-killing agents could be produced on a large scale - pun not intended!.

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