Bench Press

The heartbeat of the news.

Ever since June 25, 2009, Michael Jackson’s death has been the talk of the nation, his face plastered over web articles, newspapers, and television stations. His death broke the record for the number of users on Yahoo news at any one point in time, topping even President Barack Obama’s inauguration, and even Google believed its servers were under attack due to the sudden spike in web searches for the moon-walking legend. However, have you ever wondered why the news of the King of Pop’s untimely death has stayed in the media for so long, while other news topics, such as the death of another cultural icon, Farrah Fawcett, quickly died out?

Jon Kleinberg, Jure Leskovec, and Lars Backstroma, from the computer science department at Cornell, sought to answer these types of questions by tracking the life-cycle of news articles for a three month period during 2008. Their research included 20,000 mainstream media sites and over 90 million articles. Using a complex algorithm which could identify certain phrases in different news articles such that the computer could mark them as being of the same subject (a task that has proven to be very difficult time and time again), the team tracked the movement of news using across blogs and news sites across the Internet. Armed with an extensive pool of data to sift through and analyze, the three researchers discovered an astounding pattern that was shared throughout most news topics.

They found a consistent rhythm as stories rose into prominence and then fell off over just a few days, with a “heartbeat” pattern of handoffs between blogs and mainstream media. In mainstream media, they found, a story rises to prominence slowly then dies quickly; in the blogosphere, stories rise in popularity very quickly but then stay around longer, as discussion goes back and forth. Eventually though, almost every story is pushed aside by something newer.

Before research like this was done, many editors and journalists perceived something they described to be a “news cycle.” However, with no quantifiable data, there was no way to be confident whether this was just their perceptions or an actual phenomenon. With the information collected by these Cornell researchers, they believe the latter to be the case and have started to create mathematical models which would accurately describe the life-cycle of news.

The slow rise of a new story in the mainstream, the researchers suggest, results from imitation – as more sites carried a story, other sites were more likely to pick it up. But the life of a story is limited, as new stories quickly push out the old. A mathematical model based on the interaction of imitation and recency predicted the pattern fairly well, the researchers said, while predictions based on either imitation or recency alone couldn’t come close.

This type of news excites me because it shows how technology and the Internet have produced a tangible result (in this case, a physical model to the life cycle of a news article) to a question that would have been unsolvable 20 years ago. Truly the capabilities of technology to solve even the most abstract problems are limitless.

(Image Credit)

CO₂ + 2 H₂O + light –> (CH₂O)_n + H₂O + O₂

The equation above was the first thing I ever learned about photosynthesis. A simple equation that stated that the input of water, carbon dioxide, and light would allow a plant to produce sugar, water, and oxygen. The equation is just a simple overview of the impressive chain of events that take place within each cell of a plant undergoing photosynthesis. While scientists have studied and admired photosynthesis in great detail; producing a cost-effective artificial system for harnessing light for energy has proven to be a difficult proposition.

Today, much of the research being done focuses on finding ways to improve efficiency of solar cells thereby making them more cost effective. Some research is even being done to produce artificial “trees” that contain solar cells in the leaves as well as piezoelectric elements to harness kinetic energy from the wind and rain. While all these different approaches are promising and are obviously photosynthesis inspired none of them truly imitate the basic chemical reaction that is the crux of photosynthesis. That’s why I was really impressed when I read about researchers, at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory, who’ve discovered nanocrystals of cobalt oxide are capable of splitting water with only the application of visible light.

An excerpt from Physorg.com’s article:

Green plants perform the photooxidation of water molecules within a complex of proteins called Photosystem II, in which manganese-containing enzymes serve as the catalyst. Manganese-based organometallic complexes modeled off Photosystem II have shown some promise as photocatalysts for water oxidation but some suffer from being water insoluble and none are very robust. In looking for purely inorganic catalysts that would dissolve in water and would be far more robust than biomimetic materials, Frei and Jiao turned to cobalt oxide, a highly abundant material that is an an important industrial catalyst. When Frei and Jiao tested micron-sized particles of cobalt oxide, they found the particles were inefficient and not nearly fast enough to serve as photocatalysts. However, when they nano-sized the particles it was another story.

“The yield for clusters of cobalt oxide (Co₃O₄) nano-sized crystals was about 1,600 times higher than for micron-sized particles,” said Frei, “and the turnover frequency (speed) was about 1,140 oxygen molecules per second per cluster, which is commensurate with solar flux at ground level (approximately 1,000 Watts per square meter).”

Frei and Jiao hope to tie this breakthrough into a liquid fuel producing system that’s renewable and scrubs the atmosphere of CO₂ in the process. With their work on cobalt oxide they’ve made an important first step in producing a viable artificial photosynthetic system. I sure hope nature’s ok with us taking a page from her playbook.

(Image Credit – Simple Photosynthesis , Image Credit – Aritifical photosynthesis concept , Complete Physorg.com article)

*edited the photosynthesis formula meant to use the general one, but instead I used some wack combination of the two.

Part of why I became so interested in science as a kid (apart from watching Bill Nye) was seeing the application of science in medicine. Seeing the development of new medicinal techniques thanks to innovative research made a lasting impression on me. I guess that’s why a level of childhood excitement tends to pop up when I read about things like new imaging technology and future surgical innovations.

A schematic of Dr. King's cancer filtering concept. E-selectin attracts the cancer cells thereby exposing them to TRAIL as they "roll" along the device wall. This triggers the cancer cell's death. Image: Kuldeep Rana

Once again I felt that childhood excitement popping up as I read about a new device being developed by Dr. Michael King and his group at Cornell designed to someday remove cancerous cells from a patient’s bloodstream. King’s device takes advantage of a well studied mechanism of our immune system which is the recruitment of white blood cells to blood vessel walls with adhesion molecules known as selectins. Since selectins recruit cells based on specific carbohydrates Dr. King realized that this adhesive property could be utilized for slowing down cancer cells in order to target and destroy them.

After slowing down the cancer cells to a “roll” the cells can then be exposed to a protein called TRAIL (Tumor Necrosis Factor Related Apoptosis-Inducing Ligand) resulting in the release and then the apoptotic death of the cancer cells. This makes King’s device more than a simple sieve as he explains, “It’s a little more sophisticated than just filtering the blood, because we’re not just accumulating cancer cells on the surface”.

King’s device is impressive in it’s simplicity and tests of the device’s efficacy appear promising.

King’s research showed that the device can capture and kill about 30 percent of cancer cells flowing past it a single time, with the potential to kill more in the closed-loop system of the body. Used in combination with traditional cancer therapies, King said, the device could remove a significant proportion of metastatic cells, “and give the body a fighting chance to remove the rest of them.”

The team also showed that a system in which the cancer cells “roll” over the target molecules – presenting their entire surface to the molecules – is four times more effective than a static setup in which the cells and proteins make contact at a single point.

Of course as excited as I am to see this type of work being done, as Dr. King points out moving his concept to the clinic may take many years. I’m looking forward to reading the paper in Biotechnology and Bioengineering and seeing what others will come up with from Dr. King’s work.

I’ve been told biologists are just haters, but who needs to know why things have mass when we can find the Darwin particle!

A depiction of what the silicon nanowires look like. This array of nanowire detectors is able to detect single proteins in the bloodstream. Each nanowire corresponds to a different antibody. Credit: Vista Therapeutics

I can see it now. Season 43 of House M.D. House asks his team of fellows to determine the concentration of a certain protein in a patient’s bloodstream. Instead of taking multiple blood samples and performing several tests, including purifying the samples, marking the designated proteins, and using imaging technology to check for the labeled proteins, the fellows simply use special nanowire sensors to accomplish in five minutes what originally took 90 minutes. Although House may not be around for 43 seasons, the scene just described may be commonplace in hospitals all over the world. This ground-breaking technology is currently being researched by Vista Therapeutics, as they aim to provide the “ultimate sensitivity” with this new product.

Here is a description provided by the MIT Technology Review:

To make the detectors, Vista Therapeutics has licensed nanowire sensing technologies developed by Harvard University chemist Charles Lieber. Silicon nanowires, semiconducting wires as thin as two nanometers, have what Lieber calls the “ultimate sensitivity,” even with completely unprocessed samples such as blood. When a single protein binds to an antibody along the wire, the current flowing through the wire changes. Arrays of hundreds of nanowires, each designed to detect a different molecule in the same sample, can be arranged on tiny, inexpensive chips. The changes can be monitored continuously as molecules bind and unbind, making it possible to detect subtle trends over time, without requiring multiple blood draws.

The standard protein-detection technique, ELISA, is very sensitive but, Farr says, takes 90 minutes to perform. It starts with a blood draw that must be extensively processed–first to purify the proteins, then to label them with fluorescent dyes–and then tested with expensive imaging equipment in a hospital lab. “ELISA is a powerful technology for one-time measurements,” says Farr, “but there’s no existing technology for continuous biomarker measurement.”

With the ability to perform extremely precise, continuous monitoring of unprocessed blood samples, who knows what the future holds in store for nanowire detectors. You can be sure that I’ll be waiting for its debut on House.

Helpings hands? This metal-and-polymer gripper, triggered chemically, could usher in a new era of minimally invasive surgery. Credit: Timothy Leong/JHU

The other day I happened upon this article and I couldn’t help but be impressed. Today minimally invasive surgery implies smaller incisions, but incisions nonetheless. How would you like minimally invasive to mean zero incisions?  If Dr. Gracias and his colleagues have their way that may soon become a reality.

From the MIT Technology Review:

The new technology is a step toward surgical tools that move more freely inside the human body. “We want to make mobile surgical tools,” says David Gracias, a biomolecular- and chemical-engineering professor at Johns Hopkins University, who led the development of the new gripper. “The ultimate goal is to have a machine that you can swallow, or [to] inject small structures that move and can do things [on their own].”

A gripper based on the current design could respond autonomously to chemical cues in the body. For example, it might react to the biochemicals released by infected tissue by closing around the tissue, so that pieces can be removed for analysis.

Gracias and his colleagues presented the microgripper at the American Chemical Society meeting earlier this month. To demonstrate the device, they used it to grasp and maneuver tiny beads and clumps of cells in a petri dish. They have also used the device in the laboratory to perform an in vitro biopsy on a cow’s bladder. “This is the first mobile micromachine that has been shown convincingly to do very useful things,” Gracias says. “And it does not require electric power for operation.”

In it’s current iteration the gripper is maneuvered by magnets thereby removing the need for any incisions. As a scientist I can’t help but wonder when this remarkable device can be made available for laboratory use. Being able to manipulate items at a microscopic level based on chemical features could be very useful. In the meantime I look forward to a future of incision free biopsies!