From Your Heart to Your iPhone

From Your Heart to Your iPhone

  10:11:00 AM    Science Lover

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A new app gets data from an implanted device and can share it with the patient, doctors, and family.

A smart-phone app under development for heart-failure patients allows them to keep track of the pressure inside their heart as measured by an implanted sensor. That data could help patients adjust their medication to maintain a healthy pressure, much as diabetics do with insulin and blood sugar readings.

Called Pam+ (for "patient advisory module"), the app is being developed by researchers at the University of Southern California in collaboration with medical device maker St. Jude Medical. The researchers hope it will help patients better manage their health and reduce hospitalizations, which are responsible for much of the $40 million in health-care costs linked to heart failure.

In congestive heart failure, pressure builds up in the circulatory system and the heart fails to pump blood adequately to the rest of the body. Fluid pressure changes by the day, and monitoring those fluctuations continuously is essential to treating heart failure effectively. A number of implanted devices are now under development to monitor this pressure, giving patients and doctors real time data.

The PAM+ app works in conjunction with an external device—developed by St. Jude and currently in clinical tests—that is placed over the heart, where it charges the implanted sensor and downloads data from it.

The data is forwarded to a server at St. Jude that analyzes it and returns, via the app, the latest readings and information about ongoing trends. A patient who has regularly monitored his or her heart pressure over a week will see a graph of pressure readings along with the message "Your heart thanks you." Users can easily share their data with their health-care team and family.



"We want patients to be able to access data but also to be rewarded and encouraged on a daily basis, so they don't feel like their whole life is a diet," says Leslie Saxon, a cardiologist and director of the Center for Body Computing at USC, who helped develop the device.

Previous research conducted by Saxon showed that remote monitoring can improve the health of heart-failure patients and lower health-care costs. She unveiled a prototype of the app at the Body Computing conference in Los Angeles today.

Users get points for monitoring their pressure—points that might eventually be tied to iTunes or Amazon credit. "Even a traditional payer would love to reward this type of behavior," says Saxon.

She believes an app like this can also change the nature of doctors' visits. Rather than a physician giving a patient the latest test results, taken at a few points in time, the patient can show the doctor measurements of heart pressure over weeks and months, and together they can discuss the trends these reveal.

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Graphene Organic Photovoltaics: Flexible Material Only a Few Atoms Thick May Offer Cheap Solar Power

Graphene Organic Photovoltaics: Flexible Material Only a Few Atoms Thick May Offer Cheap Solar Power

  2:39:00 AM    Science Lover

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A University of Southern California team has produced flexible transparent carbon atom films that the researchers say have great potential for a new breed of solar cells.

A flow of methane and hydrogen gas mixture deposits carbon atoms as graphene on a nickel plate. The graphene later is then transferred to a plastic sheet, which is then incorporated into an organic photo voltaic (OPV) cell. (Credit: USC Viterbi School of Engineering)

"Organic photovoltaic (OPV) cells have been proposed as a means to achieve low cost energy due to their ease of manufacture, light weight, and compatibility with flexible substrates," wrote Chongwu Zhou, a professor of electrical engineering in the USC Viterbi School of Engineering, in a paper recently published in the journal ACS Nano.

The technique described in the article describes progress toward a novel OPV cell design that has significant advantages, particularly in the area of physical flexibility.

A critical aspect of any OPV photo-electronic device is a transparent conductive electrode through which light can couple with active materials to create electricity. The new work indicates that graphene, a highly conductive and highly transparent form of carbon made up of atoms-thick sheets of carbon atoms, has high potential to fill this role.

While graphene's existence has been known for decades, it has only been studied extensively since 2004 because of the difficulty of manufacturing it in high quality and in quantity.

The Zhou lab reported the large scale production of graphene films by chemical vapor deposition three years ago. In this process, the USC engineering team creates ultra thin graphene sheets by first depositing carbon atoms in the form of graphene films on a nickel plate from methane gas.

Then they lay down a protective layer of thermo plastic over the graphene layer, and then dissolve the nickel underneath in an acid bath. In the final step they attach the plastic-protected graphene to a very flexible polymer sheet, which can then be incorporated into a OPV cell.

The USC team has produced graphene/polymer sheets ranging in sizes up to 150 square centimeters that in turn can be used to create dense arrays of flexible OPV cells.

These OPV devices convert solar radiation to electricity, but not as efficiently as silicon cells. The power provided by sunlight on a sunny day is about 1000 watts per meter square. "For every 1000 watts of sunlight that hits a one square meter area of the standard silicon solar cell, 14 watts of electricity will be generated," says Lewis Gomez De Arco, a doctoral student and a member of the team that built the graphene OPVs. "Organic solar cells are less efficient; their conversion rate for that same one thousand watts of sunlight in the graphene-based solar cell would be only 1.3 watts."

But what graphene OPVs lack in efficiency, they can potentially more than make for in lower price and, greater physical flexibility. Gomez De Arco thinks that it may eventually be possible to run printing presses laying extensive areas covered with inexpensive solar cells, much like newspaper presses print newspapers.

"They could be hung as curtains in homes or even made into fabric and be worn as power generating clothing. I can imagine people powering their cellular phone or music/video device while jogging in the sun," he said.

The USC researchers say graphene OPVs would be major advance in at least one crucial area over a rival OPV design, one based on Indium-Tin-Oxide (ITO). In the USC team's tests, ITO cells failed at a very small angle of bending, while the graphene-based cells remained operational after repeated bending at much larger stress angles. This would give the graphene solar cells a decided advantage in some uses, including the printed-on-fabric applications proposed by the USC team.

Zhou and the other researchers on the USC team -- which included Yi Zhang, Cody W. Schlenker, Koungmin Ryu, and Mark E. Thompson in addition to Gomez de Arco -- are excited by the potential for this technology.

Their paper concludes that their approach constitutes a significant advance toward the production of transparent conductive electrodes in solar cells. "CVD graphene meets the most important criteria of abundance, low cost, conductivity, stability, electrode/organic film compatibility, and flexibility that are necessary to replace ITO in organic photovoltaics, which may have important implications for future organic optoelectronic devices."

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