New Nanoparticles Could Lead To End Of Chemotherapy

New Nanoparticles Could Lead To End Of Chemotherapy

  9:56:00 PM    Science Lover

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Nanoparticles specially engineered by University of Central Florida Assistant Professor J. Manuel Perez and his colleagues could someday target and destroy tumors, sparing patients from toxic, whole-body chemotherapies.

Dr. Manuel Perez and his team have been investigating
the use of nanoparticles for medicine for years.
(Credit: Jacque Brund)

Perez and his team used a drug called Taxol for their cell culture studies, recently published in the journal Small, because it is one of the most widely used chemotherapeutic drugs. Taxol normally causes many negative side effects because it travels throughout the body and damages healthy tissue as well as cancer cells.

The Taxol-carrying nanoparticles engineered in Perez's laboratory are modified so they carry the drug only to the cancer cells, allowing targeted cancer treatment without harming healthy cells. This is achieved by attaching a vitamin (folic acid) derivative that cancer cells like to consume in high amounts.

Because the nanoparticles also carry a fluorescent dye and an iron oxide magnetic core, their locations within the cells and the body can be seen by optical imaging and magnetic resonance imaging (MRI). That allows a physician to see how the tumor is responding to the treatment.

The nanoparticles also can be engineered without the drug and used as imaging (contrast) agents for cancer. If there is no cancer, the biodegradable nanoparticles will not bind to the tissue and will be eliminated by the liver. The iron oxide core will be utilized as regular iron in the body.

"What's unique about our work is that the nanoparticle has a dual role, as a diagnostic and therapeutic agent in a biodegradable and biocompatible vehicle," Perez said.

Perez has spent the past five years looking at ways nanotechnology can be used to help diagnose, image and treat cancer and infectious diseases. It's part of the quickly evolving world of nanomedicine.

The process works like this. Cancer cells in the tumor connect with the engineered nanoparticles via cell receptors that can be regarded as "doors" or "docking stations." The nanoparticles enter the cell and release their cargo of iron oxide, fluorescent dye and drugs, allowing dual imaging and treatment.

"Although the results from the cell cultures are preliminary, they are very encouraging," Perez said.

A new chemistry called "click chemistry" was utilized to attach the targeting molecule (folic acid) to the nanoparticles. This chemistry allows for the easy and specific attachment of molecules to nanoparticles without unwanted side products. It also allows for the easy attachment of other molecules to nanoparticles to specifically seek out particular tumors and other malignancies.

Perez's study builds on his prior research published in the prestigious journal Angewandte Chemie Int. Ed. His work has been partially funded by a National Institutes of Health grant and a Nanoscience Technology Center start-up fund.

"Our work is an important beginning, because it demonstrates an avenue for using nanotechnology not only to diagnose but also to treat cancer, potentially at an early stage," Perez said.

Perez, a Puerto Rico native, joined UCF in 2005. He works at UCF's NanoScience Technology Center and Chemistry Department and in the Burnett School of Biomedical Sciences in the College of Medicine. He has a Ph.D. from Boston University in Biochemistry and completed postdoctoral training at Massachusetts General Hospital, Harvard Medical School's teaching and research hospital.

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WinCDEmu : Mounting a disc image was never so easy – just double-click and you’re done!

WinCDEmu : Mounting a disc image was never so easy – just double-click and you’re done!

  10:12:00 PM    Science Lover

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If you play video games on your PC on a regular basis, you are bound to need a disc-mounting tool.

Honestly, playing a game off its ISO image loaded on your hard disk is so much faster than playing the same through its DVD. Disc images also go a long way in preserving your DVD – and when you are buying a game for around Rs 1,000, you want to make sure the disc lasts for as long as it can!

So after you create a disc image, how do you load it up on to your computer? The normal course is to use a ‘mounting’ tool such as Daemon Tools or Alcohol.

These programs create a virtual optical disc drive on your computer and load, or ‘mount’, the disc image onto it. The final product is as good as having a DVD in a drive! But the process to use Daemon Tools and Alcohol is long and tedious.

First, you have to run the program; then create a virtual drive through a series of three clicks; and then go on to load the image through a further four clicks. Things have got to be simpler than this, right? Well, that’s where WinCDEmu comes in.

Cutting out all the various steps in mounting a disc image, this software works automatically to give you the most streamlined interface possible. All you have to do is install the program and double-click your ISO image for the program to automatically create a virtual drive and load up the image.

It’s really that simple! And the tedious process of unmounting a disc and getting rid of the virtual drive has also been cut down: just right click the virtual drive, hit ‘eject’ and you’re done.

Supporting ISO, CUE, BIN, RAW and IMG file formats, the application can create an unlimited number of virtual drives at a time. A must-have for any gamer!

Rating: 5/5
Download: wincdemu.sysprogs.org
Direct Download: biznetnetworks.dl.sourceforge.net/sourceforge/wincdemu/WinCDEmu-2.2.exe
Size: 782.10 KB

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Scientists compute odds of interplanetary merger

Scientists compute odds of interplanetary merger

  8:54:00 PM    Science Lover

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Clash of the titans: Artist illustration depicts
collision between Earth and Venus

According to a study released Wednesday, there is a small, one-in-2500 chance that Earth will collide with Venus or Mars in 3.5 billion years.

Using powerful computers, Jacques Laskar, a researcher at the Observatoire de Paris, France, generated numerical simulations of orbital instability over the next five billion years.

Unlike previous models, they took into account Albert Einstein’s theory of general relativity. It resulted in dramatically different orbital paths.

The researchers looked at 2,501 possible scenarios, 25 of which ended with a severely disrupted Solar System.

“There is one scenario in which Mars passes 794 kilometres from Earth,” said Laskar. “When you come that close, it is the same as a collision as the planets gets torn apart.”

Laskar and colleagues ran additional two hundred computer models, slightly changing the path of Mars each time.

All but five of them ended in a two-way collision involving the Sun, Earth, Mercury, Venus or Mars. A quarter of them saw Earth smashed to pieces.

The cause of orbital chaos was the planet Mercury, found the study, published in the British journal Nature.

“Mercury is the trigger, and would be the first planet to be destabilised because it has the smallest mass,” explained Laskar. At some point Mercury’s orbit would get into resonance with that of Jupiter, throwing the smaller orb even more out of kilter, he said.

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A cheaper, lighter and longer-lasting alternative to modern batteries

A cheaper, lighter and longer-lasting alternative to modern batteries

  9:56:00 PM    Science Lover

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MOBILE phones looked like bricks in the 1980s. Indeed, they were so cumbersome that most were installed in cars. That was because the batteries required to power them were so hefty. When lithium-ion batteries were invented, mobile phones became small enough to be carried in a pocket or slipped into a handbag. Now a new design of battery that uses oxygen from ambient air to power devices could provide even smaller and lighter sources of power. Not only that, such batteries would be cheaper and last for longer between charges.

Lithium-ion batteries have two electrodes immersed in an electrically conductive solution, called an electrolyte. One of the electrodes, the cathode, is made of lithium cobalt oxide; the other, the anode, is composed of carbon. When the battery is being charged, positively charged lithium ions break away from the cathode and travel in the electrolyte to the anode, where they meet electrons brought there by a charging device. When electricity is needed, the anode releases the lithium ions, which rapidly move back to the cathode. As they do so, the electrons that were paired with them in the anode during the charging process are released. These electrons travel around an external circuit to which the battery is attached and power it.

Peter Bruce and his colleagues at the University of St Andrews in Scotland came up with the idea of replacing the lithium cobalt oxide electrode with a cheaper and lighter alternative. They designed an electrode made from porous carbon and lithium oxide. They knew that lithium oxide forms naturally from lithium ions, electrons and oxygen, but, to their surprise, they found that it could also be made to separate easily when an electric current passed through it. They exposed one side of their porous carbon electrode to an electrolyte rich in lithium ions and put a mesh window on the other side of the electrode through which air could be drawn. Oxygen from the air took the place of the cobalt oxide.

When they charged their battery, the lithium ions migrated to the anode where they combined with electrons from the charging device. When they discharged it, lithium ions and electrons were released from the anode. The ions crossed the electrolyte and the electrons travelled round the external circuit. The ions and electrons then met at the cathode, where they combined with the oxygen to form lithium oxide that filled the pores in the carbon.

Because the oxygen being used by the battery comes from the surrounding air rather than having to be carried around inside the battery, the device that Dr Bruce’s team has designed can be a mere one-eighth to one-tenth the size and weight of modern batteries, while still carrying the same charge. Alternatively, batteries using the new technology would last eight to ten times longer than modern batteries of the same size.

Performance and size are not the only expected improvements. Although they are not yet commercially available, making such a battery is expected to be cheaper. Lithium cobalt oxide accounts for 30% of the cost of a lithium-ion battery. Air, however, is free.

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Stem Cells Cultured On Contact Lens Restore Sight In Patients With Blinding Corneal Disease

Stem Cells Cultured On Contact Lens Restore Sight In Patients With Blinding Corneal Disease

  8:12:00 PM    Science Lover

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In a world-first breakthrough, University of New South Wales (UNSW) medical researchers have used stem cells cultured on a simple contact lens to restore sight to sufferers of blinding corneal disease.

Dr. Di Girolamo and Dr. Watson.
(Credit: Image courtesy of University of New South Wales)

Sight was significantly improved within weeks of the procedure, which is simple, inexpensive and requires a minimal hospital stay.

The research team from UNSW’s School of Medical Sciences harvested stem cells from patients’ own eyes to rehabilitate the damaged cornea. The stem cells were cultured on a common therapeutic contact lens which was then placed onto the damaged cornea for 10 days, during which the cells were able to re-colonise the damaged eye surface.

While the novel procedure was used to rehabilitate damaged corneas, the researchers say it offers hope to people with a range of blinding eye conditions and could have applications in other organs.

A paper detailing the breakthrough appears in the journal Transplantation this week.

The trial was conducted on three patients; two with extensive corneal damage resulting from multiple surgeries to remove ocular melanomas, and one with the genetic eye condition aniridia. Other causes of cornea damage can include chemical or thermal burns, bacterial infection and chemotherapy.

“The procedure is totally simple and cheap,” said lead author of the study, UNSW’s Dr Nick Di Girolamo. “Unlike other techniques, it requires no foreign human or animal products, only the patient’s own serum, and is completely non-invasive.

The surgeon who carried out the procedure and managed the patients was UNSW senior lecturer, Dr Stephanie Watson.

"The operation is relatively non-invasive. The patient merely comes into the hospital for a couple of hours to have their eye prepared and the lens put in place, and then they're able to go home," she said.

“There’s no suturing, there is no major operation: all that’s involved is harvesting a minute amount – less than a millimeter – of tissue from the ocular surface,” said Dr Di Girolamo.

“If you’re going to be treating these sorts of diseases in third world countries all you need is the surgeon and a lab for cell culture. You don’t need any fancy equipment.”

Because the procedure uses the patient’s own stem cells harvested from their eye, it is ideal for sufferers of unilateral eye disease. However, it also works in patients who have had both eyes damaged, Dr Di Girolamo said.

“One of our patients had aniridia, a congenital condition affecting both eyes. In that case, instead of taking the stem cells from the other cornea, we took them from another part of the eye altogether – the conjunctiva – which also harbours stem cells.

“The stem cells were able to change from the conjunctival phenotype to a corneal phenotype after we put them onto the cornea. That’s the beauty of stem cells,” Dr Di Girolamo said.

The therapeutic contact lens used in the trial was of a type commonly used worldwide after ocular surface surgery. However, of the several brands on the market, only one was suitable for growing the stem cells.

“We don’t know why. It’s probably to do with the components the manufacturers have used in that particular lens,” Dr Di Girolamo said.

The researchers are hopeful the technique can be adapted for use in other parts of the eye, such as the retina, and even in other organs. “If we can do this procedure in the eye, I don’t see why it wouldn’t work in other major organs such as the skin, which behaves in a very similar way to the cornea,” Dr Di Girolamo said.

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Magnetic Tremors Pinpoint The Impact Epicenter Of Earthbound Space Storms

Magnetic Tremors Pinpoint The Impact Epicenter Of Earthbound Space Storms

  2:22:00 AM    Science Lover

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Using data from NASA's THEMIS mission, a team of University of Alberta researchers has pinpointed the impact epicenter of an earthbound space storm as it crashes into the atmosphere, and given an advance warning of its arrival.

Artist's concept of a solar storm breaking through the earth's magnetic field. (Credit: NASA)

The team's study reveals that magnetic blast waves can be used to pinpoint and predict the location where space storms dissipate their massive amounts of energy. These storms can dump the equivalent of 50 gigawatts of power, or the output of 10 of the world's largest power stations, into Earth's atmosphere.

The energy that drives space storms originates on the sun. The stream of electrically charged particles in the solar wind carries this energy toward Earth. The solar wind interacts with Earth's magnetic field. Scientists call the process that begins with Earth's magnetic field capturing energy and ends with its release into the atmosphere a geomagnetic substorm.

"Substorm onset occurs when Earth's magnetic field suddenly and dramatically releases energy previously captured by the solar wind," said David Sibeck, project scientist for the Time History of Events and Macroscale Interactions During Substorms (THEMIS) mission at NASA Goddard Spaceflight Center in Greenbelt, Md.

Physicists Jonathan Rae and Ian Mann lead the University of Alberta research team that recently located a substorm's epicenter of the impact. The team uses ground-based observatories spread across northern Canada and the five satellites of the THEMIS mission to detect magnetic disturbances as storms crash into the atmosphere. Using a technique the researchers call "space seismology," they look for the eye of the storm hundreds of thousands of miles above Earth.

"We see the benevolent side of space storms in the form of the Northern Lights," said Mann. "When electrically charged particles speed toward Earth and buffet the atmosphere, the result is often a dancing, shimmering light over the polar region." But there is also a hazardous side. Earth's atmosphere protects us from the damaging direct effects of the radiation from space storms, but in space there is nowhere to hide. High-energy, electrically charged particles released by space storms can damage spacecraft. On Earth, disturbances caused by the particles and the electrical currents they carry can interrupt radio communications and global positioning system (GPS) navigation, and damage electric power grids.

Rae and Mann's team has also determined that the magnetic tremors show that the space storm impact into the atmosphere has a unique epicenter, with the eye of the storm located in space beyond the low-Earth orbits of most communication satellites.

Guided by Earth's magnetic field, the magnetic tremors rocket through space toward Earth. These geomagnetic substorms trigger magnetic sensors on the ground as they impact the atmosphere. The effects of these storms, and the most spectacular displays of the Northern Lights, follow a few minutes later.

The objective of NASA's pioneering multi-spacecraft THEMIS mission is to determine what causes geomagnetic substorms. In addition to a well-instrumented fleet of five spacecraft, THEMIS operates a network of ground observatories stretching across Canada and the United States to place the spacecraft observations in their global context. All night long, every night, the observatories take 3-second time resolution snapshots of the aurora and measure corresponding variations in Earth's magnetic field strength and direction every half second.

An analysis of the auroral movies and magnetic variations by Dr. Jonathan Rae from the University of Alberta pinpointed just when and where one substorm explosively released its magnetic energy. "Undulating auroral features and ripples in Earth's magnetic field began at the same time and propagated away from Sanikulaq, Nunavut, Canada at speeds on the order of 60,000 miles per hour, much like the blast wave from a gigantic explosion," said Sibeck. Dr. Rae and his team presented the results on May 25 at the American Geophysical Union meeting in Toronto.

Probing the eye of a space storm and recognizing the advance warning signs are crucial for researchers trying to understand and predict space weather. Key questions about when and how space storms start are still challenging researchers on the THEMIS team. Like forecasters on Earth who predict severe weather, the University of Alberta researchers are using their "space seismology" technique to investigate methods to forecast space storms.

THEMIS is a NASA-funded mission and involves scientists from Canada, the United States, and Europe. Current Canadian activity is funded by the Canadian Space Agency.

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Air-fueled Battery Could Last Up To 10 Times Longer: Ground-breaking Technology For Electric Cars

Air-fueled Battery Could Last Up To 10 Times Longer: Ground-breaking Technology For Electric Cars

  9:55:00 AM    Science Lover

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A new type of air-fuelled battery could give up to ten times the energy storage of designs currently available.

Diagram of the STAIR (St Andrews Air) cell. Oxygen drawn from the air reacts within the porous carbon to release the electrical charge in this lithium-air battery. (Credit: Image courtesy of Engineering and Physical Sciences Research Council (EPSRC))

This step-change in capacity could pave the way for a new generation of electric cars, mobile phones and laptops.

The research work, funded by the Engineering and Physical Sciences Research Council (EPSRC), is being led by researchers at the University of St Andrews with partners at Strathclyde and Newcastle.

The new design has the potential to improve the performance of portable electronic products and give a major boost to the renewable energy industry. The batteries will enable a constant electrical output from sources such as wind or solar, which stop generating when the weather changes or night falls.

Improved capacity is thanks to the addition of a component that uses oxygen drawn from the air during discharge, replacing one chemical constituent used in rechargeable batteries today. Not having to carry the chemicals around in the battery offers more energy for the same size battery. Reducing the size and weight of batteries with the necessary charge capacity has been a long-running battle for developers of electric cars.

The STAIR (St Andrews Air) cell should be cheaper than today’s rechargeables, too. The new component is made of porous carbon, which is far less expensive than the lithium cobalt oxide it replaces.

This four-year research project, which reaches its halfway mark in July, builds on the discovery at the university that the carbon component’s interaction with air can be repeated, creating a cycle of charge and discharge. Subsequent work has more than tripled the capacity to store charge in the STAIR cell.

Principal investigator on the project, Professor Peter Bruce of the Chemistry Department at the University of St Andrews, says: “Our target is to get a five to ten fold increase in storage capacity, which is beyond the horizon of current lithium batteries. Our results so far are very encouraging and have far exceeded our expectations.”

“The key is to use oxygen in the air as a re-agent, rather than carry the necessary chemicals around inside the battery,” says Bruce.

The oxygen, which will be drawn in through a surface of the battery exposed to air, reacts within the pores of the carbon to discharge the battery. “Not only is this part of the process free, the carbon component is much cheaper than current technology,” says Bruce. He estimates that it will be at least five years before the STAIR cell is commercially available.

The project is focused on understanding more about how the chemical reaction of the battery works and investigating how to improve it. The research team is also working towards making a STAIR cell prototype suited, in the first instance, for small applications, such as mobile phones or MP3 players.

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Refined Hubble Constant Narrows Possible Explanations For Dark Energy

Refined Hubble Constant Narrows Possible Explanations For Dark Energy

  8:49:00 PM    Science Lover

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This is a Hubble Space Telescope photo of the spiral galaxy NGC 3021. This was one of several hosts of recent Type Ia supernovae observed by astronomers to refine the measure of the universe's expansion rate, called the Hubble constant. Hubble made precise measurements of Cepheid variable stars in the galaxy, highlighted by green circles in the four inset boxes. These stars pulsate at a rate that is matched closely to their intrinsic brightness. (Credit: NASA, ESA, and A. Riess (STScI and JHU))

Whatever dark energy is, explanations for it have less wiggle room following a Hubble Space Telescope observation that has refined the measurement of the universe's present expansion rate to a precision where the error is smaller than five percent.

The new value for the expansion rate, known as the Hubble constant, or Ho (after Edwin Hubble who first measured the expansion of the universe nearly a century ago), is 74.2 kilometers per second per megaparsec (error margin of ± 3.6). The results agree closely with an earlier measurement gleaned from Hubble of 72 ± 8 km/sec/megaparsec, but are now more than twice as precise.

The Hubble measurement, conducted by the SHOES (Supernova Ho for the Equation of State) Team and led by Adam Riess, of the Space Telescope Science Institute and the Johns Hopkins University, uses a number of refinements to streamline and strengthen the construction of a cosmic "distance ladder," a billion light-years in length, that astronomers use to determine the universe's expansion rate.

Hubble observations of pulsating stars called Cepheid variables in a nearby cosmic mile marker, the galaxy NGC 4258, and in the host galaxies of recent supernovae, directly link these distance indicators. The use of Hubble to bridge these rungs in the ladder eliminated the systematic errors that are almost unavoidably introduced by comparing measurements from different telescopes.

Riess explains the new technique: "It's like measuring a building with a long tape measure instead of moving a yard stick end over end. You avoid compounding the little errors you make every time you move the yardstick. The higher the building, the greater the error."

Lucas Macri, professor of physics and astronomy at Texas A&M, and a significant contributor to the results, said, "Cepheids are the backbone of the distance ladder because their pulsation periods, which are easily observed, correlate directly with their luminosities. Another refinement of our ladder is the fact that we have observed the Cepheids in the near-infrared parts of the electromagnetic spectrum where these variable stars are better distance indicators than at optical wavelengths."

This new, more precise value of the Hubble constant was used to test and constrain the properties of dark energy, the form of energy that produces a repulsive force in space, which is causing the expansion rate of the universe to accelerate.

By bracketing the expansion history of the universe between today and when the universe was only approximately 380,000 years old, the astronomers were able to place limits on the nature of the dark energy that is causing the expansion to speed up. (The measurement for the far, early universe is derived from fluctuations in the cosmic microwave background, as resolved by NASA's Wilkinson Microwave Anisotropy Probe, WMAP, in 2003.)

Their result is consistent with the simplest interpretation of dark energy: that it is mathematically equivalent to Albert Einstein's hypothesized cosmological constant, introduced a century ago to push on the fabric of space and prevent the universe from collapsing under the pull of gravity. (Einstein, however, removed the constant once the expansion of the universe was discovered by Edwin Hubble.)

"If you put in a box all the ways that dark energy might differ from the cosmological constant, that box would now be three times smaller," says Riess.

"That's progress, but we still have a long way to go to pin down the nature of dark energy."

Though the cosmological constant was conceived of long ago, observational evidence for dark energy didn't come along until 11 years ago, when two studies, one led by Riess and Brian Schmidt of Mount Stromlo Observatory, and the other by Saul Perlmutter of Lawrence Berkeley National Laboratory, discovered dark energy independently, in part with Hubble observations. Since then astronomers have been pursuing observations to better characterize dark energy.

Riess's approach to narrowing alternative explanations for dark energy--whether it is a static cosmological constant or a dynamical field (like the repulsive force that drove inflation after the big bang)--is to further refine measurements of the universe's expansion history.

Before Hubble was launched in 1990, the estimates of the Hubble constant varied by a factor of two. In the late 1990s the Hubble Space Telescope Key Project on the Extragalactic Distance Scale refined the value of the Hubble constant to an error of only about ten percent. This was accomplished by observing Cepheid variables at optical wavelengths out to greater distances than obtained previously and comparing those to similar measurements from ground-based telescopes.

The SHOES team used Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) and the Advanced Camera for Surveys (ACS) to observe 240 Cepheid variable stars across seven galaxies. One of these galaxies was NGC 4258, whose distance was very accurately determined through observations with radio telescopes. The other six galaxies recently hosted Type Ia supernovae that are reliable distance indicators for even farther measurements in the universe. Type Ia supernovae all explode with nearly the same amount of energy and therefore have almost the same intrinsic brightness.

By observing Cepheids with very similar properties at near-infrared wavelengths in all seven galaxies, and using the same telescope and instrument, the team was able to more precisely calibrate the luminosity of supernovae. With Hubble's powerful capabilities, the team was able to sidestep some of the shakiest rungs along the previous distance ladder involving uncertainties in the behavior of Cepheids.

Riess would eventually like to see the Hubble constant refined to a value with an error of no more than one percent, to put even tighter constraints on solutions to dark energy.

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Swine Flu Outbreak Illuminated By Avian Flu Research

Swine Flu Outbreak Illuminated By Avian Flu Research

  9:15:00 PM    Science Lover

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A new study by University of Maryland researchers suggests that the potential for an avian influenza virus to cause a human flu pandemic is greater than previously thought. Results also illustrate how the current swine flu outbreak likely came about.

This graphic shows why the Type A virus can't be eradicated.
(Credit: Image courtesy of University of Maryland)

As of now, avian flu viruses can infect humans who have contact with birds, but these viruses tend not to transmit easily between humans. However, in research recently published in the Proceedings of the National Academy of Sciences, Associate Professor Daniel Perez from the University of Maryland showed that after reassortment with a human influenza virus, a process that usually takes place in intermediary species like pigs, an avian flu virus requires relatively few mutations to spread rapidly between mammals by respiratory droplets.

"This is similar to the method by which the current swine influenza strain likely formed," said Perez, program director of the University of Maryland-based Prevention and Control of Avian Influenza Coordinated Agricultural Project, AICAP. "The virus formed when avian, swine, and human-like viruses combined in a pig to make a new virus. After mutating to be able to spread by respiratory droplets and infect humans, it is now spreading between humans by sneezing and coughing."

Image via Wikipedia

In his study, Perez used the avian H9N2 influenza virus, one that is on the list of candidates for human pandemic potential. Using reverse genetics, a technique whereby individual genes from viruses are separated, selected, and put back together, Perez and his team created a hybrid human-avian virus. Their research hybrid has internal human flu genes and surface avian flu genes from the H9N2 virus. Though it comes from a different strain of avian flu than the one that contributed to the hybrid virus now causing the swine flu outbreak, Perez's research virus is similar in origin to the swine flu virus, in that both involved a combination of avian and human influenza viruses.

Perez infected ferrets (considered a good model for human influenza transmission) with the virus he created, and allowed the virus to mutate in the species. Before long, healthy ferrets that shared air space but not physical space with the infected ferret had the virus, showing that the virus had mutated to spread by respiratory droplets.

When the genetic sequences of the mutant virus and original hybrid virus were compared, the only differences were five amino acid mutations, three on the surface, and two internally. Two of the surface mutations were determined to be solely responsible for supporting respiratory droplet transmission. Because so few mutations were necessary to make the hybrid H9N2 transmissible this way, they concluded that after an animal-human hybrid influenza virus forms in nature, a human pandemic of this virus is potentially just a few mutations away.

"We do not know if the mutations we saw in the lab are the same that have made the H1N1 swine flu transmissible by respiratory droplets," Perez said. "We will be doing more research on the current swine flu strain to study its specific genetic mutations."

Perez found that one of the two of the genetic mutations in his lab strain that enabled respiratory transmission between mammals was on the tip of the HA surface protein, one of the sites where human antibodies created in response to current vaccines would bind.

"Because the binding site of the mutant virus is different from the virus upon which the vaccine is modeled, it may mean that current vaccine stocks would not be as effective against the H9N2 mutant strain as previously anticipated," said Perez. "We should keep this in mind when designing vaccines for an avian flu pandemic in humans."

However, scientists cannot predict what the actual mutations will look like if and when they occur in nature, or even which strain of avian influenza will mutate to infect mammals.

"This is just the tip of the iceberg," said Perez. "Many more studies have to be done to see which combinations of mutations cause this type of transmission before we can design the appropriate vaccines."

Perez will be talking this week with the NIH and the CDC to discuss his team's role in researching the current swine flu virus strain. Perez will likely do studies related to vaccine development, virus transmission between humans and animals, and the pathogenesis of the virus.

A virus vaccine is derived from the virus itself. The vaccine consists of virus components or killed viruses that mimic the presence of the virus without causing disease. These prime the body's immune system to recognize and fight against the virus. The immune system produces antibodies against the vaccine that remain in the system until they are needed. If that virus, or in some cases a closely similar one is later introduced into the system, those antibodies attach to viral particles and remove them before they have time to replicate, preventing or lessening symptoms of the virus.

The immune system also retains antibodies to a virus after being infected with it, so humans have general immunity to human strains of avian influenza strains. But humans do not generally have immunity to avian flu strains because they have not been infected by them before. The surface proteins are sufficiently different to escape the human immune response. Avian flu strains are therefore more dangerous for humans because the human immune system cannot recognize the virus or protect against it.

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Single-molecule Nano-vehicles Synthesized: 'Fantastic Voyage' Not So Far-Fetched

Single-molecule Nano-vehicles Synthesized: 'Fantastic Voyage' Not So Far-Fetched

  12:58:00 AM    Science Lover

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James Tour and coworkers at Rice University synthesized a molecular car with four carbon-based wheels that roll on axles made from linked carbon atoms. The nano-car's molecular wheels are 5,000 times smaller than a human cell. A powerful technique that allows viewing objects at the atomic level called scanning tunneling microscopy reveals the wheels roll perpendicular to the axles, rather than sliding about like a car on ice as the car moves back and forth on a surface. (Credit: Y. Shirai/Rice University)

Imagine producing vehicles so small they would be about the size of a molecule and powered by engines that run on sugar. To top it off, a penny would buy a million of them.

A new article published in the May 2009 issue of Scientific American asks readers to do just that.

The concept is nearly unthinkable, but it's exactly the kind of thing occupying National Science Foundation supported researchers at Penn State and Rice universities.

For several years, Ayusman Sen, who heads Penn State's department of chemistry, and his colleague Thomas E. Mallouk, director of the Center for Nanoscale Science at Penn State, have investigated technologies that could realize these remarkable machines whose uses might include delivering medicine to specific tissue, accomplishing surgeries or communicating with the outside world from inside the human body.

Though researchers consistently have improved ways to build nano-machines, the stumbling block has been finding a way to power them. Shrinking energy producers--internal combustion engines, electric motors or jet engines--below millimeter dimensions is not an easy task, but researchers may be closer to a fantastic solution.

In the 1966 movie Fantastic Voyage, scientists shrink a submarine to microscopic size and inject it into the blood stream of a brilliant scientist, who has a blood clot forming in his brain. The nano-sized surgeons then set out to remove the blood clot.

Today, researchers can steer nano-machines, use them to convey cargo, and guide them using electromagnetic forces or chemical interactions. All of this, they say, makes the world seen in Fantastic Voyage not so far-fetched.

The article -- "How to Build Nanotech Motors" is available on the Scientific American web site at: http://www.sciam.com/article.cfm?id=how-to-build-nanotech-motors

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