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Moving x-rays

Orthopaedic injuries are among the commonest reasons for visiting the doctor, and yet they can be among the hardest to diagnose correctly - especially if a complex joint like a shoulder, knee or elbow is involved.

The problem is that current diagnosis tools such as x-rays and MRI and CT scans do not work so well with injuries that only reveal themselves when a joint is in motion. Surgeons sometimes even have to operate just to make an accurate diagnosis of a complex injury.

Now Scott Banks, an engineer at the University of Florida, has designed a robot - or rather two robots that work in conjunction - capable of following and peering into patients as they move around. The device can shadow the sufferer’s movements as they walk, climb stairs, stand up from a sitting position, all the pinpointing the injury.

Banks and his team hope this will lead to much better diagnoses and assessments of the success of an operation. He suggests the system could even be used to track sports injuries with patients simulating, for example, a baseball swing.

The mechanism consists of two robots, one which shoots x-ray video and another to hold an image sensor and it has a 1m mechanical arm which follows the patient’s movement by tracking a light emitting diode (LED) lit patch attached to him or her. The robot takes its cue from the patch, a series of wall cameras and a networked computer.

At the moment, the prototype has a fixed base meaning the patient has to restrict their movements to small space, but the developers want to eventually put the device on wheels so it literally follows you around.

While Banks has applied for a patent, there are problems that still have to be ironed out - for example, it can’t yet track the LED patch with the accuracy needed for video x-rays.

University of Florida: http://www.ufl.edu/

Printing cells

A harmless procedure for producing ultra-fine droplets of live cells for use in medical research has been developed, using a variant of a traditional ink-jet printer.

According to New Scientists, if the technology stands up to longer term tests it could lead allow doctors to build replacement tissue one cell at a time, giving them much more control over the tissue they are grafting.

While ink-jet printers have been used to spray cell droplets in laboratories, these are often too large - because ultra-fine nozzles are prone to blocking - and hence can contain too many cell clusters for a doctor to use. The “electro-spray” developed by a team from University College London and King’s College London can produce droplets as small as a few micrometres in diameter and containing only a handful of cells.

Instead of squeezing out individual droplets through a nozzle, the new spray printer uses a method called electro-hydrodynamic jetting. As the liquid flows out of the nozzle, scientists apply a high voltage to it. The charge then interacts with an electrical field between the nozzle and the page breaking the flow up into a spray of tiny droplets.

The device has been tested on human T-cells and mouse brain cells which appeared to suffer no harm from the process, but more experiments are needed to ensure the cells aren’t effected in the long term.

University College London: http://www.ucl.ac.uk/

King’s College London: http://www.kcl.ac.uk/

Tiny clean machine

Moving from the microscopic to the nano world, a minute motor has recently been developed by scientists, but unlike other molecular machines this one is entirely solar powered.

The first, built over six years by a team from the University of Bologna and UCLA, resembles a dumb-bell approximately 6 nanometres long which threads through a ring about 1.3 nanometres wide. The ring can move up and down the rod of the dumb-bell but cannot pass the bigger stoppers at either end.

The ring moves back and forth along the rod like a tiny piston. When one of the stoppers absorbs sunlight it transfers an electron to the resting place of the ring which prompts it move over to the other side of the rod. The ring then returns to the old site after the electron transfers back to the stopper and the cycle starts again.

The motions are rapid with the whole process taking less than one-thousandth of a second - the equivalent of car’s engine running at 60,000 revolutions per second, according to the the project team leader.

As the system is powered by light, there is no need for fuel and no waste product is produced making it a clean and simple process.

So far the little motors do swim around randomly in solution acting independently of each other so they can’t do any useful work. But the researchers are working on how to line the them on to surfaces and membranes so they can all work together - and a perform a function on the macroscopic scale.

The sort of function these motor could perform are only at the theoretical stage, but one possible use could be operating nanovalves to control the release of nanoparticles delivering medical drugs into a patient’s bloodstream.

University of Bologna: http://www.eng.unibo.it/PortaleEn/default.htm

University of California, Los Angeles: http://www.ucla.edu/

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