Water, water, everywhere ... but is it safe to drink?

"Over the last couple of generations, there has been a huge amount of groundwater pollution worldwide, and this has had a negative impact on our drinking water supply," says Barbara Sherwood Lollar, Canada Research Chair in Isotope Geochemistry of the Earth and the Environment at the University of Toronto.

Sherwood Lollar took part in the THINK CANADA Press Breakfast Sunday at AAAS. Her research examines society's efforts to reverse and stop groundwater pollution, and the effectiveness of bioremediation technologies -- using microbes to clean up organic contaminants such as petroleum hydrocarbons (oil, gasoline or diesel) or chemicals used in the electronics or transportation industries.

While the disposal of these organic contaminants tends to be well regulated today, this has not always been the case. Lax regulations and enforcement during the period immediately after the Second World War has left Europe and North America with a legacy of past contamination.

"This contamination has had a pervasive impact on the environment," says Sherwood Lollar. "It is still out there, and it needs to be dealt with."

Over the past decade, many techniques used to clean up groundwater contamination have harnessed the power of microbiology and the work of geochemists like Sherwood Lollar. "We are not genetically engineering microbes," she explains. "In many settings, naturally occurring microbes feed off the organic contaminants and, in the process, convert them to non-toxic end products."

Until now, the real difficulty has been in proving that the process exists and that the microbes are actually cleaning up the contaminants. Sherwood Lollar has developed techniques that show where the clean-up is happening and, just as importantly, where it is not.

"Elements like carbon have different stable isotopes: Carbon-12 and Carbon-13. One is slightly heavier than the other, and the microbes tend to feed mostly on the lighter one. When the microbes have been working for some time, the ratio of heavy-to-light carbon will change. It is this change -- referred to as an isotopic signature -- that lets us know the water is being cleaned up," says Sherwood Lollar.

By cleaning up contaminated groundwater, it is possible to recuperate what would otherwise be a lost resource. The technique is starting to be used by regulators, and Sherwood Lollar is working with an international group of scientists to put together a guidance document for the United States Environmental Protection Agency (EPA).

This will provide a set of recommendations about use in the field for practitioners, which will be a first step towards mainstreaming the technique.

"It's a common misconception that water -- and especially our supply of groundwater -- is a renewable resource," says Sherwood Lollar. "But it isn't. So, it is particularly important that we manage it well and that we do whatever we can to conserve, protect and remediate what we have."

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The above story is based on materials provided by Natural Sciences and Engineering Research Council. Note: Materials may be edited for content and length.

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Students testing Indian toilets

Breathable fabric used in field test traps waste and allows only tiny water vapor molecules through

A group of University of Delaware students and researchers spent New Year's in an unconventional way -- installing sanitation systems in India.

A team of researchers led by Steven K. Dentel, professor of civil and environmental engineering, has been working for several years on a breathable fabric that can be used to line pit toilets and other basic sanitary facilities in developing nations.

Approximately 2.5 billion people around the world are still without adequate sanitation, which leads to water contamination responsible for hundreds of thousands of deaths each year. About a billion people still have to defecate in the open, without any privacy or sanitary facilities.

The fabric Dentel and his team are developing is similar to that used in sports jackets and raincoats; it only allows tiny water vapor molecules through.

Dentel realized this could be a valuable way to filter out liquid water from human waste, letting the pure water escape while retaining everything else. Sewage placed in a container of this fabric would become dehydrated and therefore less hospitable to bacteria and other disease-causing organisms.

Funded by the Bill and Melinda Gates Foundation, the project has been in the works for some time. The lab results look promising, but must still be tested in the field.

On Dec. 28, a small group led by doctoral student Shray Saxena headed to India to begin the first field test of the new fabric.

"A lot of people in India right now don't have improved toilet systems," says Saxena. "Even in cities like Kanpur, which are really quite developed, people do not have these facilities available to them."

Because sanitation in these cities is often decentralized, an advantage of this disposal system is that it does not require connection to central water or sewage lines.

Families in two cities, Kanpur and Puri, are trying out the new "eco-vapor" toilet system, with sewage collected in 55-gallon drums lined with the breathable fabric, allowing water vapor to evaporate.

The group is observing how the fabric performs under varying conditions of heat and humidity, which affect the rate at which water diffuses through the membrane. If external humidity is high, the lined drums may fill up before enough of the water can evaporate.

The nongovernmental organization WaterAid India is partnering with the research group on site selection and implementation of the pilot project.

In addition to Saxena, the team that went to India included Paul Imhoff, professor of civil and environmental engineering, doctoral student Babak Ebraziakhshayesh and two undergraduate students, Kelsey McWilliams and Dianna Kitt.

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The above story is based on materials provided by University of Delaware. Note: Materials may be edited for content and length.

3-D 'pop-up' silicon structures: Transforming planar materials into 3-D microarchitectures

3D microstructures of device-grade silicon formed using concepts similar to those in children's 'pop-up' books. The images correspond to colorized scanning electron micrographs. The silicon has a thickness of 2 microns

Researchers at the University of Illinois at Urbana-Champaign have developed a unique process for geometrically transforming two dimensional (2D) micro/nanostructures into extended 3D layouts by exploiting mechanics principles similar to those found in children's 'pop-up' books.

Complex, 3D micro/nanostructures are ubiquitous in biology, where they provide essential functions in even the most basic forms of life. Similar design strategies have great potential for use in a wide variety of human-made systems, from biomedical devices to microelectromechanical components, photonics and optoelectronics, metamaterials, electronics, energy storage, and more.

Researchers noted that existing methods for forming 3D structures are either highly constrained in the classes of materials that can be used, or in the types of geometries that can be achieved.

"Conventional 3D printing technologies are fantastic, but none offers the ability to build microstructures that embed high performance semiconductors, such as silicon," explained John Rogers, a Swanlund Chair and professor of materials science and engineering at Illinois. "We have presented a remarkably simple route to 3D that starts with planar precursor structures formed in nearly any type of material, including the most advanced ones used in photonics and electronics. A stretched, soft substrate imparts forces at precisely defined locations across such a structure to initiate controlled buckling processes that induce rapid, large-area extension into the third dimension. The result transforms these planar materials into well-defined, 3D frameworks with broad geometric diversity."

Potential applications range from battery anodes, to solar cells, to 3D electronic circuits and biomedical devices.

"The 3D transformation process involves a balance between the forces of adhesion to the substrate and the strain energies of the bent, twisted elements that make up the planar precursors," explained Sheng Xu, a postdoctoral fellow and co-author of the research paper. "Basically, we print 2D structures onto a pre-strained elastomer substrate with selected bonding points. Releasing the substrate to its original shape induces buckling processes that lift the weakly bonded regions of the 2D structure out of contact with the surface. The resulting spatially dependent deformations occur in an ordered sequence to complete the 3D assembly."

These motions follow precisely the predictions of 3D computational models of the mechanics. These models, in turn, serve as rapid, inverse design tools for realizing a wide range of desired shapes.

Compatibility with the most advanced materials (e.g. monocrystalline inorganics), fabrication methods (e.g. photolithography) and processing techniques (e.g. etching, deposition) from the semiconductor and photonics industries suggest many possibilities for achieving sophisticated classes of 3D electronic, optoelectronic, and electromagnetic devices.

"With this scheme, diverse feature sizes and wide-ranging geometries can be realized in many different classes of materials," stated postdoctoral fellow and co-author Zheng Yan. "Our initial demonstrations include experimental and theoretical studies of more than forty representative geometries, from single and multiple helices, toroids and conical spirals, to structures that resemble spherical baskets, cuboid cages, starbursts, flowers, scaffolds, fences and frameworks, each with single and/or multiple level configurations, constructed in various materials, including semiconductors, conductors and dielectrics."

"This work establishes the concepts and a framework of understanding. We're now exploiting these ideas in the construction of high performance electronic scaffolds for actively guiding and monitoring growth of tissue cultures, and networks for 3D electronic systems that can bend and shape themselves to the organs of the human body. We're very enthusiastic about the possibilities." Rogers added.

Rogers is the director of the Frederick Seitz Materials Research Laboratory and an affiliate of the Beckman Institute for Advanced Science and Technology at Illinois. He also holds affiliate appointments in the departments of bioengineering, chemistry, electrical and computer engineering, and mechanical science and engineering. With his research teams, Rogers has pioneered flexible, stretchable electronics, creating pliable products such as cameras with curved retinas, medical monitors in the form of temporary tattoos, a soft sock that can wrap an arrhythmic heart in electronic sensors, and LED strips thin enough to be implanted directly into the brain to illuminate neural pathways. His work in photovoltaics serves as the basis for commercial modules that hold the current world record in conversion efficiency.

This research was supported by the U.S. Department of Energy Office of Science. In addition to Xu, Yan, and Rogers, co-authors of the paper, "Assembly of micro/nanomaterials into complex, three-dimensional architectures by compressive buckling," include Yan, Kyungin Jang, Wen Huang, Haoran Fu, Jeonghyun Kim, Zijun Wei, Matthew Flavin, Joselle McCracken, Renhan Wang, Adina Badea, Yuhao Liu,1 Dongqing Xiao, Guoyan Zhou, Jungwoo Lee, Ha Uk Chung, Huanyu Cheng, Wen Ren, Anthony Banks, Xiuling Li, Ungyu Paik, Ralph G. Nuzzo, and Yonggang Huang and Yihui Zhang (Northwestern University).

Story Source:

The above story is based on materials provided by University of Illinois College of Engineering. The original article was written by Rick Kubetz. Note: Materials may be edited for content and length.

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Journal Reference:

1. Sheng Xu, Zheng Yan, Kyung-In Jang, Wen Huang, Haoran Fu, Jeonghyun Kim, Zijun Wei, Matthew Flavin, Joselle McCracken, Renhan Wang, Adina Badea, Yuhao Liu, Dongqing Xiao, Guoyan Zhou, Jungwoo Lee, Ha Uk Chung, Huanyu Cheng, Wen Ren, Anthony Banks, Xiuling Li, Ungyu Paik, Ralph G. Nuzzo, Yonggang Huang, Yihui Zhang, and John A. Rogers. Assembly of micro/nanomaterials into complex, three-dimensional architectures by compressive buckling. Science, 9 January 2015: 154-159 DOI:10.1126/science.1260960

Wave energy integration costs should compare favorably to other energy sources

The Ocean Sentinel has been deployed off the Oregon Coast, one of the nation's first wave energy testing devices

A new analysis suggests that large-scale wave energy systems developed in the Pacific Northwest should be comparatively steady, dependable and able to be integrated into the overall energy grid at lower costs than some other forms of alternative energy, including wind power.

The findings, published in the journal Renewable Energy, confirm what scientists have expected -- that wave energy will have fewer problems with variability than some energy sources and that by balancing wave energy production over a larger geographic area, the variability can be even further reduced.
The variability of alternative energy sources is one factor that holds back their wider use -- if wind or solar energy decreases and varies widely, then some other energy production has to back it up, and that adds to the overall cost of energy supply.
"Whenever any new form of energy is added, a challenge is to integrate it into the system along with the other sources," said Ted Brekken, an associate professor and renewable energy expert in the College of Engineering at Oregon State University.
"By producing wave energy from a range of different sites, possibly with different types of technology, and taking advantage of the comparative consistency of the wave resource itself, it appears that wave energy integration should be easier than that of wind energy," he said. "The reserve, or backup generation, necessary for wave energy integration should be minimal."
This estimate of the cost of integrating wind energy indicated that it would be 10 percent or less than the actual charges being made for the integration of wind energy. Energy integration, however, is just one component of the overall cost of the power generated. Wave energy, still in the infancy of its development, is not yet cost competitive on an overall basis.
Wave energy is not now being commercially produced in the Pacific Northwest, but experts say its future potential is significant, and costs should come down as technologies improve and more systems are developed. This study examined the hypothetical addition of 500 megawatts of generating capacity in this region by 2025, which would be comparable to approximately five large wind farms.
Another strength of wave energy, the study suggested, is that its short-term generation capacity can be predicted with a high degree of accuracy over a time scale ranging from minutes to hours, and with some accuracy even seasonally or annually.
The Pacific Northwest has some of the nation's best wave energy resources, and as a result is home to the Northwest National Marine Renewable Energy Center, supported by the U.S. Department of Energy.
Wave energy in the region is expected to spur economic growth, help diversify the energy portfolio, reduce greenhouse gas emissions and reduce transmission losses, the study noted.

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Story Source:
The above story is based on materials provided by Oregon State University. Note: Materials may be edited for content and length.

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Journal Reference:

1. Simon C. Parkinson, Ken Dragoon, Gordon Reikard, Gabriel García-Medina, H.Tuba Özkan-Haller, Ted K.A. Brekken. Integrating ocean wave energy at large-scales: A study of the US Pacific Northwest. Renewable Energy, 2015; 76: 551 DOI: 10.1016/j.renene.2014.11.038

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That smartphone is giving your thumbs superpowers

While neuroscientists have long studied brain plasticity in expert groups--musicians or video gamers, for instance--smartphones present an opportunity to understand how regular life shapes the brains of regular people

When people spend time interacting with their smartphones via touchscreen, it actually changes the way their thumbs and brains work together, according to a report in the Cell Press journal Current Biology on December 23. More touchscreen use in the recent past translates directly into greater brain activity when the thumbs and other fingertips are touched, the study shows.

"I was really surprised by the scale of the changes introduced by the use of smartphones," says Arko Ghosh of the University of Zurich and ETH Zurich in Switzerland. "I was also struck by how much of the inter-individual variations in the fingertip-associated brain signals could be simply explained by evaluating the smartphone logs."
It all started when Ghosh and his colleagues realized that our newfound obsession with smartphones could be a grand opportunity to explore the everyday plasticity of the human brain. Not only are people suddenly using their fingertips, and especially their thumbs, in a new way, but many of us are also doing it an awful lot, day after day. Not only that, but our phones are also keeping track of our digital histories to provide a readymade source of data on those behaviors.
Ghosh explains it this way: "I think first we must appreciate how common personal digital devices are and how densely people use them. What this means for us neuroscientists is that the digital history we carry in our pockets has an enormous amount of information on how we use our fingertips (and more)."
While neuroscientists have long studied brain plasticity in expert groups--musicians or video gamers, for instance--smartphones present an opportunity to understand how regular life shapes the brains of regular people.
To link digital footprints to brain activity in the new study, Ghosh and his team used electroencephalography (EEG) to record the brain response to mechanical touch on the thumb, index, and middle fingertips of touchscreen phone users in comparison to people who still haven't given up their old-school mobile phones.
The researchers found that the electrical activity in the brains of smartphone users was enhanced when all three fingertips were touched. In fact, the amount of activity in the cortex of the brain associated with the thumb and index fingertips was directly proportional to the intensity of phone use, as quantified by built-in battery logs. The thumb tip was even sensitive to day-to-day fluctuations: the shorter the time elapsed from an episode of intense phone use, the researchers report, the larger was the cortical potential associated with it.
The results suggest to the researchers that repetitive movements over the smooth touchscreen surface reshape sensory processing from the hand, with daily updates in the brain's representation of the fingertips. And that leads to a pretty remarkable idea: "We propose that cortical sensory processing in the contemporary brain is continuously shaped by personal digital technology," Ghosh and his colleagues write.
What exactly this influence of digital technology means for us in other areas of our lives is a question for another day. The news might not be so good, Ghosh and colleagues say, noting evidence linking excessive phone use with motor dysfunctions and pain.

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Story Source:
The above story is based on materials provided by Cell Press. Note: Materials may be edited for content and length.

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Journal Reference:

1. Arko Ghosh et al. Use-Dependent Cortical Processing from Fingertips in Touchscreen Phone Users. Current Biology, December 2014 DOI: 10.1016/j.cub.2014.11.026

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Live adaptation of organ models in the OR | sci-engineeringscience.blogspot.com

The non-deformed liver model (red) adapts to the deformed surface profile (blue) | sci-engineeringscience.blogspot.com

During minimally invasive operations, a surgeon has to trust the information displayed on the screen: A virtual 3D model of the respective organ shows where a tumor is located and where sensitive vessels can be found. Soft tissue, such as the tissue of the liver, however, deforms during breathing or when the scalpel is applied. Endoscopic cameras record in real time how the surface deforms, but do not show the deformation of deeper structures such as tumors. Young scientists of the Karlsruhe Institute of Technology (KIT) have now developed a real-time capable computation method to adapt the virtual organ to the deformed surface profile.

The principle appears to be simple: Based on computer tomography image data, the scientists construct a virtual 3D model of the respective organ, including the tumor, prior to operation. During the operation, cameras scan the surface of the organ and generate a stiff profile mask. To this virtual mold, the 3D model then is to fit snuggly, like jelly to a given form. The Young Investigator Group of Dr. Stefanie Speidel analyzed this geometrical problem of shape adaptation from the physical perspective. "We model the surface profile as electrically negative and the volume model of the organ as electrically positive charged," Speidel explains. "Now, both attract each other and the elastic volume model slides into the immovable profile mask." The adapted 3D model then reveals to the surgeon how the tumor has moved with the deformation of the organ.

Simulations and experiments using a close-to-reality phantom liver have demonstrated that the electrostatic-elastic method even works when only parts of the deformed surface profile are available. This is the usual situation at the hospital. The human liver is surrounded by other organs and, hence, only partly visible by endoscopic cameras. "Only those structures that are clearly identified as parts of the liver by our system are assigned an electric charge," says Dr. Stefan Suwelack who, as part of Speidel's group, wrote his Ph.D. thesis on this subject. Problems only arise, if far less than half of the deformed surface is visible. To stabilize computation in such cases, the KIT researchers can use clear reference points, such as crossing vessels. Their method, however, in contrary to others does not rely on such references from the outset.

In addition, the model of the KIT researchers is more precise than conventional methods, because it also considers biomechanical factors of the liver, such as the elasticity of the tissue. So for instance, the phantom liver used by the scientists consists of two different silicones: A harder material for the capsule, i.e. the outer shell of the liver, and a softer material for the inner liver tissue.

As a result of their physical approach, the young scientists also succeeded in accelerating the computation process. As shape adaptation was described by electrostatic and elastic energies, they found a single mathematical formula. Using this formula, even conventional computers equipped with a single processing unit only work so quickly that the method is competitive. Contrary to conventional computation methods, however, the new method is also suited for parallel computers. Using such a computer, the Young Investigator Group now plans to model organ deformations stably in real time.

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The above story is based on materials provided by Karlsruhe Institute of Technology. Note: Materials may be edited for content and length.

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Journal Reference:

1. Stefan Suwelack, Sebastian Röhl, Sebastian Bodenstedt, Daniel Reichard, Rüdiger Dillmann, Thiago dos Santos, Lena Maier-Hein, Martin Wagner, Josephine Wünscher, Hannes Kenngott, Beat P. Müller, Stefanie Speidel. Physics-based shape matching for intraoperative image guidance. Medical Physics, 2014; 41 (11): 111901 DOI: 10.1118/1.4896021