This section was edited by Associate Editor Jeffrey Winters.

TRACKING ANTI-CANCER MISSILE

Researchers at Rice University in Houston have developed a technique that can find and treat some types of cancers in a single pass. But to ensure that this experimental therapy, which involves nanoscale particles that heat and destroy cancer cells, is effective, the Rice researchers had to come up with a way to track the progress of these anti-cancer missiles through the body.

The missile is actually a nanoshell—a spherical nanoparticle consisting of a dielectric core which is covered by a thin layer of gold. These shells, designed by Rice biomedical engineering professor Naomi Halas, absorb light that would otherwise pass through the body; this absorbed energy is converted to heat, which can kill cancer cells.

Attached to the nanoshells are fluorescent dyes, an antibody tuned to bind to certain types of cancer cells, and a bit of iron oxide. The antibodies enable the anti-cancer missile to home in on cancer cells even if the nanoparticles are injected elsewhere in the body. The fluorescent dye allows pathologists to find the cells under a microscope to determine if they were destroyed.

And the iron oxide? Initially, it was added to enhance the fluorescent effect of the dye, but the iron shows up strongly under magnetic resonance imaging. The hope is that when this therapy begins clinical trials doctors will be able to track the location of the nanoparticles through MRI, and when the particles have accumulated in a tumor, the area would be illuminated to kill the cancer cells.

Thus far, the particles have only been tested in Petri dishes. Animal testing is the next step, with human trials a few years away.

The research was first reported in the journal, Advanced Functional Materials.

BACTERIAL CONTROL

DESIGNING MICROMACHINES THAT OPERATE THROUGH BROWNIAN MOTION IS A SIMPLE TRICK.

A ratchet keeps a wheel from going backward, so random forces either propel the wheel forward or not at all. But researchers at Argonne National Laboratory and Northwestern University in Evanston, Ill., have built a micromachine that can be controlled, indirectly at least, by oxygen.

The research was first published in the Proceedings of the National Academy of Sciences.

These microscale gears are immersed in a nutrient broth. They turn
when bacteria bump into their jagged teeth.

The researchers fabricated a ratcheted microgear with slotted spokes, something quite similar to what other groups have built to capture Brownian motion. They immersed this gear set into a bath populated with a common bacteria. Bacillus subtilis is an aerobic bacteria, which requires oxygen to function. In a well-aerated solution, the bacteria swim around friskily, and when they bump into the gear they provide enough force to turn it.

Indeed, the researchers placed multiple gears with teeth set in opposition; the force of colliding bacteria powered the gears to turn in opposite directions.

A crude control system was established for the gears, as well. To slow down the gears, the researchers reduced the amount of oxygen available in the solution. Lacking oxygen, the aerobic bacteria became sluggish, and the gears slowed down as a result. To stop the gears entirely, the oxygen supply was cut off. Without oxygen, the bacteria lapsed into a sort of hibernation state.

The gears in the experiment were not linked to anything that would produce useful work. The research suggests a way for engineers to power and control micromachines implanted in the human body or other fluid-filled environments.

PORT PROTECTION

In a globalized economy, a container port is a uniquely vulnerable facility. Ideally, every container would be scanned for nuclear, biological, or chemical weapons smuggled within the legitimate cargo. But the time necessary to conduct such thorough searches would bring trade to a grinding halt.

VeriTainer Corp., a Fremont, Calif., company that makes crane-mounted container scanning systems and solutions, has received a U.S. patent, 7,612,338, for the VeriSpreader shipping container monitoring system that works by scanning shipping containers with crane-mounted nuclear detection technology.

With the use of a twist lock signal from a real-time monitoring system on a crane, the VeriSpreader can distinguish which container is being scanned and when.

According to VeriTainer, the Veri-Spreader has been tested by performing tens of thousands of scans in a live port environment.  According to John I. Alioto, CEO of VeriTainer. “The ’338 patent was born out of 15 months of intensive trials at the Port of Oakland. This patent is the first in a series of patents that will come about as a result of our Oakland trials.”

Matthew Alioto, the company’s vice president of engineering and one of the inventors named on the patent, said, “It would be very challenging to come up with a real-time method for effectively separating the scans and matching them to a container without utilizing the twist lock signal. Seamless operation is the driving force behind the VeriSpreader technology, and the ’338 patent is based on that very key concept.”

CELL PHONE FOR THE DEAF

Handing a cell phone to a deaf person might seem like a cruel gesture. Sure, he might be able to send out a text message with it, but the expressiveness with which the deaf use sign language would be completely lost.

But a team of researchers at Cornell University in Ithaca, N.Y., are working to change that situation. If the technology they are working on bears fruit, it could lead to phones that can transmit sign language.

Already, prototype cell phones are in the hands of 25 deaf users in the Seattle area.

The Mobile ASL project began in 2004. From the beginning, the project focused on a means to transmit video of each half of a signed conversation through the limited bandwidth available to most cell phone users. The standard 2G cell phone network, for instance, provides only 15 to 20 kilobits of data per second. That’s enough to transmit voice conversations, but is inadequate for real-time video; YouTube video streams at about 600 kilobits per second. (In countries where higher bandwidth cell phones are commonplace, deaf people are using ordinary mobile phones to transmit sign language.)

Some of the solutions the team, led by Cornell engineering professor Sheila Hemami, has come up with are purely technical—compressing the video to ten frames a second, for instance. But the engineers working on the project have had to learn about how deaf people interact with one another when signing.

Although American Sign Language includes gestures that involve both hands at once, the researchers found that deaf people are capable of adapting it to use with one hand when necessary. That makes it possible to hold the phone with one hand and sign with the other.

Also, the researchers discovered that facial expressions are vital for understanding ASL. To convey that information, the video feed should supply finely grained details of the face and hands while providing less data about the rest of the body and the background.

SMART BLOOD

FOR PATIENTS SUFFERING TRAUMATIC INJURIES OR UNDERGOING INVASIVE SURGERY, BLOOD TRANSFUSIONS CAN MEAN THE DIFFERENCE BETWEEN LIFE AND DEATH. But if the blood to be transfused has gotten too warm or is the wrong type, the procedure could be worse than useless. That’s why a new identification system developed at the Fraunhofer Institute for Integrated Circuits could become a lifesaver. It will enable crucial information about the blood to be carried electronically on the bag itself.





The system relies on smart tags that will be embedded on the blood bags as well as on patient wrist bands. The technology uses radio nodes instead of RFID tags to transmit data about the blood and the patient. Technicians would prompt the blood tag and the patient tag to exchange information; if the donor blood is of an incompatible type, an alarm would sound to alert the technician that the blood types don’t match.

The Fraunhofer Institute developed the system with help from T-Systems, Vierling, delta T and the University of Erlangen-Nuremberg.

Passive RFID tags were rejected for this application because the necessary readers broadcast with enough power—as much as two watts—to interfere with other devices in the hospital. By contrast, the intelligent radio node developed by the researchers includes its own battery and processing unit. That means it needs only to transmit enough signal to be picked up by an external reader. That necessary power is in the milliwatt range.

It’s expected that the smart tags will help hospitals better manage blood supplies. Sometimes more blood is requested by a surgeon than is needed; unless that blood was kept cold, it would have to be disposed of. The active technology in the smart tag could keep track of the temperature of the bag and alert technicians if the blood has exceeded a predetermined level. If not, the blood could be returned to the bank and be used again.

The system can be used elsewhere in the hospital. Smart tags attached to hospital equipment could report their locations to a central computer, which would keep critical devices from turning up lost. Maintenance and repair histories might also be kept on the tags.

The smart tag system is now in the midst of a field test in a hospital in Germany. If successful, the system could be more widely deployed by 2012.

STRAW ANTENNAE

There’s a little give in most antennas, but as anyone who has had a car aerial snapped off can attest, all antennas have their breaking points. It’s only natural, since antennas are made of metals that have limits to their ability to spring back into shape.


A narrow channel in this silicone ribbon holds liquid metal, much as a drinking straw holds water.

Now engineers at North Carolina State University in Raleigh have produced a prototype antenna that can take all sorts of abuse and return to its original shape.

The secret of their antenna is in the metal that carries the electromagnetic signal. The germanium-indium alloy the team used is liquid at room temperature. Injected into the narrow channel of a silicone strip, the antenna can be bent and twisted without breaking.

Because the frequency of an antenna is determined in part by its length and shape, playing too rough with the rubbery antenna can, in a sense, tune it to a new radio channel.

But the team of researchers led by engineering professor Michael Dickey said this could have its advantages. For instance, a wireless strain sensor attached to a bridge would see its broadcast frequency change if its antenna were stretched by movement of structural parts.

MEASURING NANOPARTICLES

Public health scientists have had a low-key but steady concern about the potential for nanoparticles—nanoscale bits of engineered material—to cause serious environmental or medical problems. One of the key worries has been that individual nanotubes or nanodots are difficult to detect using conventional means. Now researchers at Washington University in St. Louis have developed an instrument capable of detecting and measuring a single nanoscale particle.

The research, led by Lan Yang, a professor of systems engineering at Washington University, was first published in the December 13 issue of Nature Photonics.

The new sensor is an improved version of a sensor called a whispering-gallery microresonator. Such sensors employ the same principle as whispering galleries in such buildings as the U.S. Capitol; these ellipsoid-shape rooms enable the smallest sound made at one focal point to be clearly heard at the other focal point, many feet away. A much louder noise made at the same spot is all but unintelligible because the sound waves reflect off the walls a number of times, muddying the signal.

The researchers have built a device with similar properties, except that light, not sound, is reflected. Laser light is channeled into a ring-like waveguide; when the light strikes the boundary of the ring, it is reflected back into the waveguide.

When the wavelength of the laser light exactly matches the path length inside the waveguide, the waves superimpose and create a resonance, which acts analogously with the whispering gallery. However, if a particle attached itself to the outer surface of the glass ring, it can change the path length of the waveguide ever so slightly. That change would be all but impossible to detect, except that it destroys the resonance for a particular wavelength of light. Comparing the new resonance wavelength to the original can provide a measurement of the size of the attached particle.

To get an accurate reading, the ring must be flawless. Most waveguides are built on silicon wafers using etching technology similar to what is used to make semiconductors, and it results in rings with small flaws on their surfaces. The researchers on Yang’s team smoothed their rings by pulsing a laser on them until the glass melted a bit; as the glass recooled, the surface was pulled tight.

The researchers report that the smoothed rings are so precise that a properly tuned wave of light can circle 100 million times without losing strength.

To test the capability of their sensor, the researchers deposited nanoscale particles of salt or plastic on the ring. Data from the resonator was able to derive the known size of the particles to within 1 to 2 percent.

In theory, such sensors should be able to detect and measure the size of a particle less than 100 nanometers in diameter. Further refinements will be needed to allow technicians using such a device to tell the difference between a naturally occurring virus and a runaway nanotube.

LASER PROFILES MULTIPLE PARAMETERS
By Alan S. Brown

A new laser profiling system from Bytewise Measurement Systems of Columbus, Ga., enables users to measure thickness, step height, width, angle, radius, location, gap, and depth—all in a single step. According to the company, laser profiling is three to four times more accurate than manual measurements and improves the consistency of measurements used in Six Sigma quality processes. It also automates information gathering so engineers can identify trends and problems faster.

Laser profilers are often used to monitor continuous processes, such as plastic extrusion or rubber calendering, by measuring the width or thickness of products coming out of the machine. Bytewise developed its new CrossCheck system for the quality and manufacturing test bench, and also for OEM's who want to add the capability to low-speed machines.

While CrossCheck does only 30 profiles per second, compared with 100 or more for high-end systems, it costs only $7,449 for a starter kit (and $6,990 for a build-your-own system). "It's very affordable, and costs thousands of dollars less than high-end systems," said product manager Mike Snow. "A QA group could set up station and measure parts on the line or take measurements from samples offline."

CrossCheck does this by measuring 1,280 points during each scan. It then compares the scan with a master profile. "We can't measure down into the nanometers, but if you need to measure micron-sized variations, we're four times more repeatable than calipers or a micrometer, where there are variances between one operator and the next. When you take away operator error, you improve the quality system," said Snow.

Software setup is intuitive, he added. "If you're going to be measuring several features on a part, you put a master part under the beam of sensor. This creates an image of the part. Then you draw a bounding box around the feature you want to measure, tell the software what type of feature it is—a radius, vertex, gap, bump, or whatever—and set up a tolerance.

"When you measure a part, you put it in the same spot and compare it to see if you're in or out of tolerance," Snow said.