Making Diesel at Solar Plants

Normally biofuels and solar power are considered to be competing alternative energy sources. However, some researchers are merging these technologies, trying to use the best of both to create “solar fuels.”  This includes the researchers at a small start-up company from Cambridge Massachusetts, Joule Unlimited, which was recently listed as one of the world’s ten most important emerging technologies by MIT’s Technology Review 2010 TR10. It was also selected as part of the TR50 in February, the only company besides Google that was chosen for both honors.

Joule Unlimited has manipulated and designed genes to create photosynthetic microorganisms. These microorganisms use energy from the sun to convert carbon dioxide and water directly into ethanol or hydrocarbon fuels (such as diesel). The photosynthetic microorganisms are designed with a genetic switch that limits growth. They are allowed to multiply for a couple days, then the genetic switch is flipped to divert their energy into fuel production. The microorganisms excrete the fuel, which is chemically separated and collected using conventional technologies.

The goal of this direct, continuous process is to achieve high fuel production with minimal land use. The microorganisms are grown in water inside transparent bioreactors, where they are circulated to make sure that all the microorganisms are exposed to sunlight. Different kinds of non-potable water can be used in this process, including brackish water, waste water or seawater. The microorganisms are fed concentrated carbon dioxide and other nutrients. The long term hope is to use carbon dioxide from polluting facilities such as coal plants.

Joule Unlimited claims to have specifically designed both their microorganisms and bioreactors to work in harmony together, in order to maximize fuel production. For instance, the company carefully designed the bioreactor to keep the heat within the limits required by their microorganism. In the long term, the company is hoping to produce 25,000 gallons per acre per year of ethanol and 15,000 gallons per acre per year of diesel at the competitive price of $30 per barrel. They are planning to scale up from demonstration facilities to building a commercial facility in 2012, in order to start producing diesel in 2013. However, their engineers still need to improve the performance of the microorganism to meet these targets, as well as address whatever issues arise during scale-up.

Joule Unlimited isn’t the only one working in this research area. Others working on solar fuels include:  (1) Synthetic Genomics in La Jolla, CA, (2) BioCee in Minneapolis, MN, and (3) University of Minnesota BioTechnology Institute, St. Paul, MN. Hopefully the race is on, and the winner will be all of us.

Joule facility
A diagram of how a Joule facility would work with bioreactors growing micro organisms with sunlight and CO2 in water. A separator removes the end product -- liquid fuel or chemicals. (Courtesy of Joule Unlimited)
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Want A Net-Zero Energy Home?

Berkeley Lab presents 3 talks on “The House of the Future.” Come get a preview of tomorrow’s zero-energy home with cool roofs, smart windows, and computer-driven control systems. These talks are for a general audience, on May 10 at 7-9 p.m. at the Berkeley Repertory Theatre. Free admission. More information at http://www.lbl.gov/LBL-PID/fobl/.

Risk of Invasive Breast Cancer Predicted

Way too many of my women friends have suffered through breast cancer diagnosis, starting with a close friend who died of breast cancer in her early 30s. Her death inspired me to change careers, in hopes of developing better ways to detect and stage breast cancer. Although the focus of my work has now moved on to other medical imaging areas, I still pay particular attention to new breast cancer research.

It seems like there are reports on breast cancer research in the news daily. But my eye was particularly caught by an article published online on April 28, 2010 in the Journal of the National Cancer Institute. A group of researchers, from UCSF Helen Diller Family Comprehensive Cancer Center, are now able to predict whether women with ductal carcinoma in situ are at high or low risk of developing subsequent invasive cancer.

Ductal carcinoma in situ (DCIS) is the most common type of non-invasive breast cancer. The American Cancer Society estimates that about 60,000 women are diagnosed with DCIS in the U.S. each year. This cancer starts in the milk ducts. It is called non-invasive because it hasn’t spread beyond the milk ducts into any normal surrounding breast tissue. DCIS isn’t life-threatening and it rarely leads to death from breast cancer, but having DCIS can increase your risk of developing an invasive breast cancer in the future. Approximately 11 out of 100 women diagnosed with DCIS and treated with a lumpectomy only go on to develop invasive cancer within 8 years, and about the same number go on to develop subsequent DCIS within 8 years. That means that the majority of such women have no further tumors, but these women typically still go through some form of aggressive treatment.

So we really need a way to predict which women with DCIS have a high risk of developing subsequent tumors. The UCSF scientists report that they’ve discovered a method to do just that. They collected and analyzed data for 1162 women aged 40 years or older, who were diagnosed with DCIS and treated with a lumpectomy alone in the San Francisco Bay Area. They followed and measured clinical, histopathologic, and molecular characteristics of subsequent tumors for this large population (from 63 hospitals) for 8 years.

They found that the risk of subsequent invasive cancer was significantly increased among women whose initial DCIS was detected by palpation compared with those detected by mammography. They also found that DCIS lesions that were “triple positive” for the expression of biomarkers p16COX-2and Ki67 had an even higher risk of subsequent invasive cancer. However, these factors were not associated with increased risk of subsequent DCIS. An independent set of biomarker expression and conditions was identified for increased risk of subsequent DCIS, with the lowest risk group having disease-free surgical margins of 10 mm or larger.

Based on their findings, the UCSF scientist were able to stratify the women into 4 categories for risk of subsequent invasive cancer — Lowest (17%), Low (27%), Intermediate (28%) and High (28%). The lowest risk group had only a 4% risk of developing invasive cancer within 8 years, whereas the high risk group had a 20% risk. A similar stratification was performed for risk of subsequent DCIS with similar results.

Hopefully this new method of predicting risk for subsequent cancers will help women with DCIS chose the proper treatment. Karla Kerlikowske, the lead author, states “It will lead to a more personalized approach to treatment. As many as 44 percent of the patients (i.e., lowest and low risk groups) with DCIS may not require any further treatment, and can rely on surveillance.”

Cheap Solar Using Plastic Electronics?

In order to make solar power cost-effective without governmental subsidies, we need to dramatically reduce the manufacturing costs of solar cells. (I discussed solar costs in a previous blog.) A lot of research is underway to do just that. One area of solar research focuses on finding a low-cost alternative to indium tin oxide (ITO), which is an expensive conducting material currently used in standard solar cells. ITO is a rare by-product of mining that is also used in flat-screen televisions, mobile phones, and other devices with display screens. As the demand for these popular devices increases rapidly, the price and availability of ITO for solar cells has become a real problem.

A team of chemical engineers think they’ve found the solution — plastic electronics. This collaboration of chemical engineers from Princeton University, University of Texas, and University of California Santa Barbara reported their latest results in the Proceedings of the National Academy of Sciences on March 30, 2010. Their research focuses on conductive polymers (plastics).

Conductive polymers have been around for a long time, but their ability to conduct electricity degraded when manufactured into devices. Basically the manufacturing process caused their structures to be trapped in a rigid form and that prevented electrical current to travel through them, thus severely limiting device performance.

The multi-institutional collaboration has overcome this problem, by treating the conductive polymers with dichloroacetic acid (DCA) after they are processed into the desired form. This “postdeposition solvent annealing” with DCA dramatically rearranges the structure of the polymer, resulting in a smooth film with high conductivity. As a result, they are able to make polymers that are translucent, malleable and highly conductive. These materials could have wide reaching applications as electrodes in transistors, anodes in solar cells, and light-emitting-diodes.

One amazing thing about this research is the simplicity of production. This collaboration made a transistor (a very basic device used to amplify and switch electronic signals) by printing the polymer onto a surface, using a method similar to that used by a standard ink-jet printer. In the future, they hope to distribute the conductive polymers in cartridges like printer ink.

What does this mean for solar power? An important thing for solar is that these conductive polymers are translucent. Although they are less transparent than ITO (e.g., transmissivity of 73% v.s. 84% respectively), they are dramatically cheaper. So the newly developed conductive polymers are still a promising low-cost alternative as anodes for solar cells. Hopefully this research will translate into cheap, commercially available solar cells soon.

Researchers have developed a new way to manufacture electronic devices made of plastic, employing a process that allows the materials to be formed into useful shapes while maintaining their ability to conduct electricity. In the transistor pictured above, the plastic is molded into interdigitated electrodes (orange), allowing current flow to and from the active channel (green). Courtesy of Loo Research Group.

Tiny Mobile Phone Microscope

Ozcan tiny microscope for cell phone
The prototype for the lensless microscope developed at UCLA has the approximate diameter of a US Quarter. The microscope only weighs 46 grams, about as much as a large egg. (Courtesy of Ozcan Research Group @ UCLA)

My niece has worked in remote developing nations, in places like a tiny village in South Africa where the women have to walk several hours to fetch clean water. In order to travel to such areas, she had to take malaria medication and get a lot of vaccines — such as hepatitis A and B, yellow fever, typhoid, rabies, rubella, and diphtheria vaccines. HIV and Aids can also be prevalent. Unfortunately medical care and resources are often very limited in such isolated villages, where a doctor is many miles away and the villagers may not have access to vehicles or proper roads. To address this critical need, people are using new technology to bring the patients figuratively to the doctors. For example, medical data is acquired and then transmitted to a doctor or medical specialist elsewhere for offline assessment.

This field of telemedicine is growing rapidly. Some telemedical technology relies on the fact that cell phones are now used even in the developing world, as evidenced by extensive cell phone use after the recent earthquake in Haiti. Wireless phone technology has become significantly cheaper and the technical capabilities of cell phones is rapidly improving.

Aydrogan Ozcan, a research engineer at UCLA, has created a tiny microscope that is portable and lensless for telemedicine applications. The microscope attaches using a USB connection to a smart-phone, PDA or computer. This week his group published a paper describing in detail his latest, tiniest microscope. This minature microscope weighs just 46 grams (about the same weight as a large egg) and has dimensions of about 4 cm x 4 cm x 6 cm. It can image sub-cellular structures (with 1-2 micron resolution) over a 24 mm2 imaging area.

Microscopes normally use a lens to magnify the image of an object, where the image is generated by an electromagnetic (in optical microscopes) or electron (in electron microscopes) beam passing through the sample. However, standard microscopes are bulky and expensive, so they are generally used only in laboratories.

Ozcan’s lensless miniature microscope is instead based on digital in-line holography. It uses a simple light-emitting-diode (LED) and a compact digital sensor array to capture holographic images of blood samples or other fluids. A small chip is filled with a fluid sample, such as a blood smear, that is inserted into the microscope. The LED passes incoherent light through the sample, and the interference of the light waves that pass through the cells creates a hologram of each cell. The microscope digitally records these holograms, then rapidly reconstructs images of the cells. A compressed version of each holographic image can then be transmitted to hospitals elsewhere using wireless cellular networks, which have penetrated even the most remote corners of the world.

This portable microscope can accurately identify and count cells, including red blood cells, white blood cells, platelets, and T-cells (white blood cells whose counts are important for accurate diagnosis of AIDS). So this technology could help monitor diseases like malaria, HIV, and tuberculosis. It could also be used to test water quality following a disaster, such as a major earthquake or hurricane.

Ozcan’s microscope is also durable and easy to use. You just need to fill a chip with a sample and slide the chip into the slot in the microscope. The sample doesn’t need to be perfectly aligned in the microscope, so very minimal training is needed. It also uses cheap parts and a standard smart-phone. Plus the images are analyzed automatically by a computer, instead of requiring a trained medical technician.  However, this analysis does have a potential down-side. Namely, the computer automatically identifies a cell by comparing the cell’s hologram to a cell hologram library, but I’ve seen little information on the development of this database.

Overall though this new tiny mobile phone microscope has great promise. It could become a very cost-effective tool for telemedicine applications. Next time my niece heads off to a remote village, maybe she can have a tiny microscope to attach to her smart-phone just in case?