#Iron-rich biochar filters arsenic from water Biochar may be a fast inexpensive and easy way to remove arsenic one of the world s most common pollutants from water.
For a new study researchers used used iron-enhanced carbon cooked from hickory chips to successfully remove the toxin.
and has been shown to cause cancer. ecause biochar can be produced from various waste biomass including agricultural residues this new technology provides an alternative and cost-effective way for arsenic removalsays Bin Gao associate professor of agricultural
and biological engineering at University of Florida. As reported in the journal Water Research Gao ground wood chips that were heated then in nitrogen gas but not burned.
The resulting biochar which has the consistency of ground coffee was treated then with a saltwater bath to impregnate it with iron.
Plain biochar does not have the same effect Gao says. Current methods to remove arsenic include precipitation adding lime
or coagulants to water using membranes to filter it out or using an ion exchange process.
Water treatment plants could use large biochar filters to extract the arsenic. Homeowners could use a small filter attached to their tap.
#This sticky process builds collagen fibers Rice university rightoriginal Studyposted by Mike Williams-Rice on October 28 2014new research offers a detailed look at how synthetic collagen fibers self-assemble via their sticky ends.
Discovering its secrets may lead to better synthetic collagen for tissue engineering and cosmetic and reconstructive medicine.
or as scaffolding in regenerative medicine Two papers in the Journal of the American Chemical Society the first published in May and the second this month show precisely how mimetic peptides developed at Rice may be aligned to form helices with sticky ends that allow them to aggregate into fibers
Scientists like Hartgerink design custom nanoscale chains by carefully arranging the amino acids and their positive and negative charges.
In the right order the charged amino acids crosslink into what Hartgerink calls axial salt bridges non-covalent bonds that hold the helices together with the help of stabilizing hydrogen bonds. ost of the work we ve
In the first of the new papers by Hartgerink graduate students Abihishek Jalan and Katherine Jochim demonstrate the self-assembly of standalone sticky-ended triple helices with offsets of four amino acids.
and fibers start forminghartgerink says. s soon as you have a fiber NMR doesn t work any more.
or the second paper with graduate student Biplab Sarkar and former graduate student Lesley O Leary e did the reverse of that
and synthesized a series of peptides with large sticky ends that drive fiber assemblyhartgerink says.
but different arrangements and showed those with extensive sticky ends quickly self-assembled into fibers.
either formed amorphous aggregates or remained separated in solution. e chose to satisfy the critics by breaking our work into two studies.
when you use charged pairs properly you get fibers. And when you don t you don t get fibers. nderstanding the fine details of collagen assembly presents the possibility of synthetic collagens for specific functions Hartgerink says. number of biomaterials use natural collagen
and there are advantages to replacing them with synthetic collagenshe says. ne of the main advantages is that we move away from health
#Upgraded circuits built to run biocomputers ETH Zurich rightoriginal Studyposted by Fabio Bergamin-ETH Zurich on October 27 2014.
Scientists have taken a key step toward realizing the goal of building programmable biocomputers that could detect
If cancer markers are found in a cell the circuit could for example activate a cellular suicide program.
Healthy cells without cancer markers would remain unaffected by this process. Biocomputers differ significantly from their counterparts made of silicon
and bioengineers still face several major obstacles. A silicon chip for example computes with ones and zeros current is
either flowing or not and it can switch between these states in the blink of an eye.
In contrast biological signals are less clear in addition to ignaland o signalthere is a plethora of intermediate states with little bit of signal.
This is a particular disadvantage for biocomputer components that serve as sensors for specific biomolecules and transmit the relevant signal.
A team led by ETH Zurich Professor Yaakov Benenson has developed several new components for biological circuits.
These components are key building blocks for constructing precisely functioning and programmable biocomputers. The circuit controls the activity of individual sensor components using an internal imer.
This circuit prevents a sensor from being active when not required by the system; when required it can be activated via a control signal.
The researchers recently published their work in the scientific journal Nature Chemical Biology. To understand the underlying technology it is important to know that these biological sensors consist of synthetic genes that are read by enzymes
and converted into RNA and proteins. In the controllable biosensor developed by doctoral candidate Nicolas Lapique the gene responsible for the output signal is not active in its basic state as it is installed in the wrong orientation in the circuit DNA.
The gene is activated via a special enzyme a recombinase which extracts the gene from the circuit DNA
and reinstalls it in the correct orientation making it active. he input signals can be transmitted much more accurately than before thanks to the precise control over timing in the circuitsays Benenson professor of synthetic biology who supervised Lapique s work.
To date the researchers have tested the function of their activation-ready sensor in cell culture of human kidney
and cancer cells. n electronics the different components that make up a circuit are connected always in the same way:
In biology there are a variety of different signals a host of different proteins or microrna molecules.
In order to combine biologic components in any desired sequence signal converters must be connected between them. Laura Prochazka also a doctoral candidate student under Benenson has developed a versatile signal converter.
She published her work recently in the magazine Nature Communications. A special feature of the new component is that not only it converts one signal into another
but it can also be used to convert multiple input signals into multiple output signals in a straightforward manner.
This new biological platform will significantly increase the number of applications for biological circuits. he ability to combine biological components at will in a modular plug-and-play fashion means that we now approach the stage
when the concept of programming as we know it from software engineering can be applied to biological computers.
Bioengineers will literally be able to program in futuresays Benenson. Source: ETH Zurichyou are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license N
#Tarantula venom probe shows neurons in action University of California Davis rightoriginal Studyposted by Carole Gan-UC Davis on October 24 2014a cellular probe that combines a tarantula toxin
This is the first time researchers have been able to visually observe these electrical signaling proteins turn on without genetic modification.
These visualization tools are prototypes of probes that could some day help researchers better understand the ion channel dysfunctions that lead to epilepsy cardiac arrhythmias
and other conditions. on channels have been called life s transistors because they act like switches generating electrical feedbacksays senior author Jon Sack assistant professor of physiology
and membrane biology at University of California Davis. o understand how neural systems or the heart works we need to know which switches are activated.
These probes tell us when certain switches turn on. oltage-gated channels are proteins that allow specific ions such as potassium or calcium to flow in and out of cells.
They perform a critical function generating an electrical current in neurons muscles and other cells.
and nanoparticles can be used to image live cells. To study the channels the team engineered variants of tarantula toxin that could be labeled fluorescently
For example the Kv2. 1 channel that this probe binds to leads to epilepsy when it s not functioning properly. n addition the ability to better observe electrical signaling could help researchers map the brain at its most basic levels. nderstanding the molecular
mechanisms of neuronal firing is a fundamental problem in unraveling the complexities of brain functioncohen says.
or at rest is an important proof-of-concept there s still a lot of work to be done. Sack and Cohen will continue to collaborate testing other types of spider venoms that bind to different potassium channels. he beauty of this is the potentialsack says. his is a toehold into a new way of visualizing electrical activity
We ve tagged a Ford; we should be able to tag a Chevy. he study appears in the Proceedings of the National Academy of Sciences.
The researchers who conducted this study come from UC Davis Marine Biological Laboratory at Woods Hole and the Molecular Foundry Lawrence Berkeley National Laboratory.
The NIH and the Milton L. Shifman Endowed Scholarship for the Neurobiology Course at Woods Hole supported the project.
Work at the Molecular Foundry received support from the Office of Science Office of Basic energy Sciences of the US Department of energy.
Source: UC Davisyou are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license A
#Super high-res MRI detects single atom For the first time researchers have detected a single hydrogen atom using high-resolution magnetic resonance imaging (MRI.
Conventional MRI technology widely used in hospitals can typically resolve details of up to one tenth of a millimeter for example in cross-sectional images of the human body.
In standard hospital instruments the magnetization of the atomic nuclei in the human body is measured inductively using an electromagnetic coil.
Researchers led by Christian Degen professor at the Laboratory for Solid State Physics at ETH Zurich developed a different and vastly more sensitive measurement technique for MRI signals.
In their experiments reported in the journal Science researchers measured the MRI signal with a novel diamond sensor chip using an optical readout in a fluorescence microscope.
The sensor consisted of an impurity in diamond known as the nitrogen-vacancy center. In this case two carbon atoms are missing in the otherwise regular diamond lattice
while one of them is replaced by a nitrogen atom. The nitrogen-vacancy center is both fluorescent and magnetic making it suitable for extremely precise magnetic field measurements.
For their experiment the researchers prepared an approximately 2×2 millimeter piece of diamond such that nitrogen-vacancy centers formed only a few nanometers below the surface.
By an optical measurement of the magnetization they were in several cases able to confirm the presence of other magnetic atomic nuclei in the immediate vicinity. uantum mechanics then provides an elegant proof of
The researchers also used the measured data to localize the hydrogen nuclei with respect to the nitrogen-vacancy center with an accuracy of better than one angstrom (one ten-millionth of a millimeter.
The dream of the researchers is to one day apply the technology to shed light on the spatial structure of biomolecules such as proteins.
At present researchers usually rely on X-ray crystallography to investigate protein structures. This requires growing crystals consisting of billions of identical molecules.
Crystallizing proteins is challenging and sometimes impossible researchers say. If the ETH physicists achieve their goal a single molecule would in principle suffice for determining the structure.
Another advantage of nano-MRI is that the molecules can be labeled by isotopes providing a means for site-specific image contrast.
This would help biologists tackle issues relating to protein functions more effectively o
#Tiniest particles melt and then turn into Jell-o New york University rightoriginal Studyposted by James Devitt-NYU on October 20 2014the fact that microscopic particles known as polymers
and colloids will melt as temperatures rise was no surprise to scientists. But raise the temperature a little more
The new solid is a substance like Jell-o with the polymers adhering to the colloids
The discovery points to new ways to create mart materialscutting-edge materials that adapt to their environment by taking new forms
and an NYU doctoral student at the time it was conducted. The research which appears in the journal Nature Materials reveals that the well-known Goldilocks Principle
The study focuses on polymers and colloids#particles as small as one-billionth and one-millionth of a meter in size respectively.
For instance colloidal dispersions comprise such everyday items as paint milk gelatin glass and porcelain and for advanced engineering such as steering light in photonics.
By better understanding polymer and colloidal formation scientists have the potential to harness these particles
In the Nature Materials study the researchers examined polymers and larger colloidal crystals at temperatures ranging from room temperature to 85 degrees C. At room temperature the polymers act as a gas bumping against the larger particles
and applying a pressure that forces them together once the distance between the particles is too small to admit a polymer.
In fact the colloids form a crystal using this process known as the depletion interaction#an attractive entropic force
which is a dynamic that results from maximizing the random motion of the polymers and the range of space they have the freedom to explore.
As usual the crystals melt on heating but unexpectedly on heating further they re-solidify. The solid is much softer more pliable
and more open than the crystal. This result the researchers observe reflects enthalpic attraction#the adhesive energy generated by the higher temperatures and stimulating bonding between the particles.
By contrast at the mid-level temperatures conditions were too warm to accommodate entropic force yet too cool to bring about enthalpic attraction.
Lang now a senior researcher at Exxonmobil observes that the finding may have potential in 3d printing.
The National Science Foundations NASA and the Department of energy funded the work. Source: NYUYOU are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license
#How energy loss can make lasers more intense Washington University in St louis rightoriginal Studyposted by Tony Fitzpatrick-WUSTL on October 20 2014energy loss in optical systems such as lasers is a chief hindrance
or light packets to achieve optical gain. his turns the conventional textbook understanding of lasers upside down. ut now scientists have demonstrated a more effective#yet counterintuitive#way to reap energy gains:
In other words they ve invented a way to win by losing. oo much of something can be really detrimentalsays Sahin Kaya Ozdemir a research scientist at Washington University in St louis. f you pump in more energy to get more laser intensity
and estimated the intensity of light in the two resonators and surprisingly found an initial decrease in total intensity of the two resonators followed by an increase
and finally a rebirth of strong light intensity as the loss was increased. he loss added beyond a critical value increased the total light intensity and its distribution between the resonatorssays Bo Peng a graduate student.
In a third experiment the researchers report achieving two nonlinear phenomena the Thermal Effect and a Raman gain in silica despite increasing loss. ight intensity is a very important parameter in optical systems
and here we have provided a new route to increase light intensity by modulating loss in the systemsays Lan Yang an associate professor in electrical
and systems engineering. nstead of the standard method of adding more energy into the system we re offering a more energy-efficient method. ang says that
in addition to lasing improvements their findings could lead to new schemes and techniques for controlling and reversing the effects of loss in various other physical systems such as in photonic crystal activities plasmonic structures and metamaterials.
The experimental system that the researchers used consists of two tiny directly coupled silica microtoroid (doughnut-shaped) resonators each coupled to a different fiber-taper coupler that aids in guiding light from a laser diode to photodetectors;
the fiber is tapered in the middle so that light can between the fibers and the resonators. Yang says the concept will work in any coupled physical system.
Loss is delivered to one of the microresonators by a tiny device a chromium-coated silica nanotip
whose position within the evanescent field (leaked-out light) of one of the resonator was controlled by a nanopositioner that operates at a minuscule 20-nanometer resolution. hromium is used
because it s a strongly absorbing material at a wavelength of 1550 nanometers and it gives a good dose of losspeng explains.
Another nanopositioner controls the coupling strength between the resonators by tuning their distance. The loss-gain phenomenon occurs near a feature called the exceptional point
which has a dramatic effect on a system s properties. The exceptional point has contributed to a number of counterintuitive activities
and results in recent physics studies. hen we steer the system through the exceptional point the symmetric distribution of the fields between two resonators become asymmetricozdemir says. symmetric distribution leads to field localization increasing the light intensity in one
of the resonators in this case the resonator with less loss. s a result all nonlinear processes
which depend on the intensity of light in that subsystem become affected.?The beauty of this work is in how we came to provide new schemes
and techniques to engineer a physical system by controlling lossyang adds. ormally loss is considered bad
and Engineers Army Research Office US Department of energy RIKEN ithes Project MURI Center for Dynamic Magneto-Optics Grant-in-aid for Scientific research Vienna Science and Technology Fund
and the Austrian Science Fund supported the project which also included researchers from RIKEN in Japan and the Vienna University of Technology in Austria.
Washington University in St. Louisyou are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license t
#This fusion reactor could be cheaper than coal University of Washington Posted by Michelle Ma-Washington on October 16 2014fusion energy almost sounds too good to be true#zero greenhouse gas emissions no long-lived radioactive waste a nearly unlimited fuel supply.
Perhaps the biggest roadblock to adopting fusion energy is that the economics haven t penciled out.
Fusion power designs aren t cheap enough to outperform systems that use fossil fuels such as coal and natural gas.
University of Washington engineers hope to change that. They have designed a concept for a fusion reactor that
when scaled up to the size of a large electrical power plant would rival costs for a new coal fired plant with similar electrical output.
The team published its reactor design and cost-analysis findings last spring and will present results this week at the International atomic energy agency s Fusion energy Conference in St petersburg Russia. ight now this design has the greatest potential of producing economical fusion power of any current conceptsays Thomas Jarboe a professor
of aeronautics and astronautics and an adjunct professor in physics. The reactor called the dynomak started as a class project taught by Jarboe two years ago.
After the class ended Jarboe and doctoral student Derek Sutherland#who previously worked on a reactor design at the Massachusetts institute of technology#continued to develop
and refine the concept. The design builds on existing technology and creates a magnetic field within a closed space to hold plasma in place long enough for fusion to occur allowing the hot plasma to react and burn.
The reactor itself would be largely self-sustaining meaning it would continuously heat the plasma to maintain thermonuclear conditions.
Heat generated from the reactor would heat up a coolant that is used to spin a turbine
and generate electricity similar to how a typical power reactor works. his is a much more elegant solution because the medium in
which you generate fusion is the medium in which you re also driving all the current required to confine itsutherland says.
There are several ways to create a magnetic field which is crucial to keeping a fusion reactor going.
The new design is known as a spheromak meaning it generates the majority of magnetic fields by driving electrical currents into the plasma itself.
This reduces the amount of required materials and actually allows researchers to shrink the overall size of the reactor.
Other designs such as the experimental fusion reactor project that s currently being built in France#called Iter#have to be much larger than the dynomak
because they rely on superconducting coils that circle around the outside of the device to provide a similar magnetic field.
When compared with the fusion reactor concept in France the dynomak is much less expensive#roughly one-tenth the cost of Iter
#while producing five times the amount of energy. Jarboe and colleagues factored the cost of building a fusion reactor power plant using their design
and compared that with building a coal power plant. They used a metric called vernight capital costswhich includes all costs particularly startup infrastructure fees.
A fusion power plant producing 1 gigawatt (1 billion watts) of power would cost $2. 7 billion
while a coal plant of the same output would cost $2. 8 billion according to their analysis. f we do invest in this type of fusion we could be rewarded
because the commercial reactor unit already looks economicalsutherland says. t s very exciting. ight now the concept is about one-tenth the size and power output of a final product
which is still years away. The researchers have tested successfully the prototype s ability to sustain a plasma efficiently
and as they further develop and expand the size of the device they can ramp up to higher-temperature plasma
and get significant fusion power output. The team has filed patents on the reactor concept and plans to continue developing
and scaling up its prototypes. The US Department of energy funded the work. Source: University of Washingtonyou are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license u
#This atomically thin material generates electricity Columbia University Georgia Institute of technology rightoriginal Studyposted by John Toon-Georgia Tech on October 16 2014engineers have demonstrated that a single atomic layer of molybdenum disulfide
(Mos2) Â can generate an electrical voltage when it s stretched or compressed. The effect is known as piezoelectricity.
Scientists had predicted it was theoretically possible in materials of only a few atomic thicknesses but this is the first experimental observation.
The materialâ could be the basis for unique electric generators that are lightweight bendable stretchable #and ultimately wearable. his material#just a single layer of atoms#could be made as a wearable device perhaps integrated into clothing to convert energy from your body movement to electricity
and power wearable sensors or medical devices or perhaps supply enough energy to charge your cell phone in your pocketsays James Hone professor of mechanical engineering at Columbia University
and co-leader of the research. roof of the piezoelectric effect and piezotronic effect adds new functionalities to these two-dimensional materialssays Zhong Lin Wang a professor in Georgia Tech s School of Materials science and engineering
and a co-leader of the research. he materials community is excited about molybdenum disulfide and demonstrating the piezoelectric effect in it adds
a new facet to the material. here are two keys to using molybdenum disulfide for generating current:
using an odd number of layers and flexing it in the proper direction. The material is highly polar
but Wang notes so an even number of layers cancels out the piezoelectric effect. The material s crystalline structure also is piezoelectric in only certain crystalline orientations.
For the Nature study Hone s team placed thin flakes of Mos2 on flexible plastic substrates
and determined how their crystal lattices were oriented using optical techniques. They then patterned metal electrodes onto the flakes.
In research done at Georgia Tech Wang s group installed measurement electrodes on samples provided by Hone s group then measured current flows as the samples were deformed mechanically.
They monitored the conversion of mechanical to electrical energy and observed voltage and current outputs. The researchers also noted that the output voltage reversed sign
when they changed the direction of applied strain and that it disappeared in samples with an even number of atomic layers confirming theoretical predictions published last year.
The presence of piezotronic effect in odd layer Mos2 was observed also for the first time. hat s really interesting is we ve now found that a material like Mos2 which is not piezoelectric in bulk form can become piezoelectric
when it is thinned down to a single atomic layersays Lei Wang a postdoctoral fellow in Hone s group.
To be piezoelectric a material must break central symmetry. A single atomic layer of Mos2 has such a structure
and give zero net piezoelectric effect. his adds another member to the family of piezoelectric materials for functional devicessays Wenzhuo Wu a postdoctoral fellow at Georgia Tech.
In fact Mos2 is just one of a group of 2d semiconducting materials known as transition metal dichalcogenides all of
whose piezoelectric materials remain unexplored. Importantly as has been shown by Hone and his colleagues 2d materials can be stretched much farther than conventional materials particularly traditional ceramic piezoelectrics
which are quite brittle. The research could open the door to development of new applications for the material
and its unique properties. his is the first experimental work in this area and is an elegant example of how the world becomes different
what we re learning we re eager to build useful devices for all kinds of applications. ltimately Zhong Lin Wang notes the research could lead to complete atomic-thick nanosystems that are powered self by harvesting mechanical energy
from the environment. The US Department of energy Office of Basic energy Sciences and National Science Foundation funded the project.
Source: Georgia Techyou are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license t
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