#Organic framework serves as catalyst for the photocatalytic conversion of water into hydrogen Humanity's need for energy is ever-increasing.
However, the traditional energy sources are finite. In contrast, water and sunlight are available in vast abundance.
Scientists at the Max Planck Institute for Solid State Research in Stuttgart and from LMU Munich have created now a material that uses light to produce the versatile energy source hydrogen from water.
What is needed is a substance that directly uses the energy of sunlight to split the hydrogen-oxygen bonds in water.
Bettina Lotsch's Nanochemistry Research Group at the Max Planck Institute for Solid State Research in Stuttgart and at Ludwig-Maximilians-Universität München (LMU), together with theoreticians working with Christian
COFS are highly crystalline, porous polymers in which certain parent molecules form highly regular, two-or three-dimensional network structures.
These network polymers possess suitable optical and electronic properties as well as a relatively large surface area, which in essence make them interesting candidates for photocatalytic hydrogen evolution.
the scientists had to add platinum nanoparticles and an electron donor to their powder polymer."
"The platinum nanoparticles work as microelectrodes on which the electrons are transferred from the COF to the protons to form hydrogen,
"says Vijay Vyas, a scientist in the Nanochemistry Research Group at the Stuttgart-based Max Planck Institute for Solid State Research."
which the material generated hydrogen by fine-tuning the molecular geometry of the building blocks and, hence, of the networks.
Already envisaged scenarios include its use as fuel for vehicles or for producing carbon-based energy carriers.
In fuel cells, electricity could be generated using hydrogen (and oxygen. Hydrogen which is used currently in the industry to manufacture many important chemicals could also be made available in a more sustainable fashion.
Currently, it is obtained largely using fossil raw materials. Source: Max Planck Societ c
#Gene on-off switch works like backpack strap A research team based in Houston Texas Medical center has found that the proteins that turn genes on by forming loops in human chromosomes work like the sliding plastic adjusters on a grade-schooler backpack.
This discovery could provide new clues about genetic diseases and allow researchers to reprogram cells by directly modifying the loops in genomes.
The study, which appears online in the Proceedings of the National Academy of Sciences, is by the same team that published the first high-resolution 3-D maps showing how the human genome folds inside the nucleus of a cell.
The multi-institutional group includes researchers from Baylor College of Medicine Rice Univ.,Stanford Univ. and the Broad Institute.
Every human cell contains a genome, a linear string of DNA. Sequences of DNA bases spell out genes,
much like letters spell out words. For decades, scientists have known that genes that lie far apart on the string can activate one another by looping back
and coming into contact during genome folding. Last year, the team showed that it was possible to map the positions of these loops,
and the researchers created the first atlas of loops in the human genome. But the group couldn explain how the loops were forming. or months
we had no idea what our data really meant, said senior author Erez Lieberman Aiden, a geneticist and computer scientist with joint appointments at Baylor and Rice. hen one day,
we realized that we been carrying the solution arounditerally, on our backor decades! The human genome contains more than 20,000 genes.
In any given cell, only a fraction of these are active, and this fraction determines the cell function:
whether it will become a hard-pumping heart cell, a body-defending immune cell or a metastatic cancer cell.
Aiden, who is also a senior investigator at Rice Center for Theoretical Biological Physics, said the researchers found that a set of proteins acts like the plastic slider,
a graduate student in the Aiden lab and at Stanford university. he protein complex that forms DNA loops appears to operate like the plastic slider that is used to adjust the length of the straps:
Aiden, assistant professor of genetics at Baylor and of computer science and computational and applied mathematics at Rice, said Sanborn
and study co-first author Suhas Rao showed that they could combine the tri-glide model with mathematics
and high-performance computation to predict how a genome will fold. The team confirmed their predictions by making tiny modifications in a cell genome
and showing that the mutations changed the folding pattern exactly as expected. Rao likened the result to a new form of genome surgery:
a procedure that can modify how a genome is folded by design and with extraordinary precision. e found that changing even one letter in the genetic code was enough to modify the folding of millions of other letters,
said Rao, a graduate student in the Aiden lab and at Stanford university. hat was stunning was that once we understood how the loops were forming,
the results of these changes became extremely predictable. Sanborn said the discovery also explains a puzzling pattern that the team noticed
when it published its original atlas of loops. NA encodes information and you can think of each DNA base pair as a letter and of certain sequences of letters as words,
he said. n our data, we noticed that when particular keywords appeared, a loop would form.
But the loop would only form if the two keywords were pointing at one another. For example, if one side of the loop read K-E-Y-W-O-R-D,
and the genome is flexible at that scale, said Sanborn. f I were a protein,
but they proved mathematically that such packing could not explain the data. Next, the researchers tested a model of DNA folding where tension along the DNA chain caused it to condense like an elastic band
but this model also did not fit the data. Eventually, they hit on the tri-glide model.
The basic idea is that the tri-glide protein complex lands on the genome and pulls the strand from each side so that a loop forms in the middle just like the loop someone might make
which acts like a brake, said Rao, a student in the Aiden lab and at Stanford university. o it not so much that the keywords need to point at one another;
Aiden said that one of the most astonishing implications of the new model is that loops on different chromosomes tend not to become entangled. n the old model,
when two bits of the genome wiggled around and then met inside the cell nucleus, Aiden said. ut this process would lead to interweaving loops and highly entangled chromosomes.
This is a big problem if you need those chromosomes to separate again when the cell divides. he tri-glide takes care of that,
he said. ven in a big pile of backpacks, you can use your tri-glide to make a loop without any risk of entanglement. u
An abnormally high or low white blood count, for instance, might indicate a bone marrow pathology or AIDS.
The rupturing of white blood cells might be the sign of an underlying microbial or viral infection.
Strangely shaped cells often indicate cancer. While this old, simple technique may seem a quaint throwback in the age of high-technology health care tools like genetic sequencing,
flow cytometry and fluorescent tagging, the high cost and infrastructure requirements of these techniques largely limit them to laboratory settingsomething point-of-care diagnostics aims to fix.
In a project funded by the Bill and Melinda Gates Foundation's Grand Challenges in Global Health Initiative,
a research team from Rice Univ. has developed recently a plastic, miniature digital fluorescence microscope that can quantify white blood cell levels in patients located in rural parts of the world that are removed far from the modern laboratory."
or sample preparation,"said Tomasz Tkaczyk, associate professor, Dept. of Bioengineering, Rice Univ.,Houston, Texas."Many systems which work for point-of-care applications have quite expensive cartridges.
The goal of this research is to make it possible for those in impoverished areas to be able to get the testing they need at a manageable price point."
"Tkaczyk's co-authors on this research included Rebecca Richards-Kortum, Fellow of The Optical Society and a professor in Rice's Department of Bioengineering.
Her research today involves translating molecular imaging research to point-of-care diagnosticsescribes the fluorescence microscope system this week in a paper published in Biomedical Optics Express, from The Optical Society.
How the microscope works The researchers'device identifies and quantifies lymphocytes, monocytes, and granulocyteshree types of white blood cellsn a drop of blood mixed with the staining compound acridine orange.
which consisted of one polystyrene lens and two polymethyl methacrylate aspheric lenses, the researchers used a single-point diamond turning lathe.
The lenses were enclosed then in an all-plastic, 3-D-printed microscope housing and objective.
Once constructed, the microscope provided a field of view of 1. 2 mm, allowing for at least 130 cells to be present for statistical significance
and image sensor, cost less than $3, 000 to construct. At production levels upwards of 10,000 units,
the researchers estimate that this price would fall to around $600 for each unit, with a per-test cost of a few cents.
Future work for Tkaczyk and his colleagues includes developing an automated algorithm for white blood cell identification,
The use of low cost components such as LEDS reflectors, and USB detectors, combined with the all-plastic housing and lenses will allow for future versions of the prototype to be mass-produced.
Source: The Optical Societ a
#Shortening Organic solar cell Production One of the building blocks of the solar panel, solar cells are responsible for converting solar energy into electricity.
Most commercial solar cells are made from the inorganic crystalline silicon. Now, the U s. Dept of energy (DOE) Oak ridge National Laboratory (ORNL) has developed a method to save steps in the organic solar cell manufacturing process by introducing solvents into solar cell film production.
Usually, the thin filmssed by organic bulk heterojunction solar cellsre created by mixing conjugated polymers and fullerenes,
which the lab describes as occer ball-like carbon molecules known as buckyballs. After uniformity is achieved by spin casting the mixture on a rotating substrate
the material is annealed. The annealing process reduces the material hardness, but increases its toughness. However, the new method allows scientists to bypass the thermal annealing process,
allowing for both time and cost savings. Instead of using thermal annealing, the researchers added a solvent,
which aided in dissolving fullerenes and made the film structure more uniform. Lack of uniformity in a film mixture causes clusters to form,
According to the DOE, organic photovoltaic solar cells have low efficiencies due to their small excition diffusion lengths
However, the information obtained from the neutron reflectometry will help scientists boost organic solar cell performance, according to ORNL. ptimization of photovoltaic properties provides information to manufacture solar cells with fully controlled morphology
and device performance, said Nuradhika Herath, the lead of the study. hese findings will aid in developing dealphotovoltaics,
#A otdevelopment for ultra-cold magnetic sensors Magnetoencephalography, or MEG, is a noninvasive technique for investigating human brain activity for surgical planning or research,
and has been used in hospitals and universities for more than 30 years. It's just one of the many powerful technologies made possible by a tiny device called a SQUID, short for superconducting quantum interference device.
SQUIDS can detect minuscule magnetic fields, useful in applications ranging from medical imaging of soft tissue to oil prospecting.
The most sensitive commercial magnetic sensors require a single SQUID kept at 4. 2 Kn incredibly chilly temperature that is usually maintained with expensive and difficult to handle liquid helium.
Now researchers from Loughborough Univ. and Nottingham Univ. both in the U k.,have built a multi-SQUID device that can operate at 77 Khe boiling temperature of liquid nitrogen, a much cheaper coolant.
The new device still outperforms most standard 4. 2 K SQUID magnetometers. The team reports their results in Applied Physics Letters."
"We believe there should be an immediate interest in the entire SQUID community for the potential replacement of their existing superconducting magnetic sensors based on single SQUIDS operating at 4. 2 K with our SQUID arrays operating at 77 K,
SQUIDS work by converting a measure of magnetic intensity called flux into a voltage. If you string together a series of SQUIDS the voltage output scales in direct proportion to the number of SQUIDS,
The catch is that the approach only works if all the SQUIDS experience the same magnetic flux (a condition called flux coherency)
Flux focusers are large areas of superconductor that improve magnetic field sensitivity and minimize parasitic fluxes.
they provide a magnetic sensor that is very cost effective, considering that operation of SQUIDS at 4. 2k requires the use of liquid helium-4,
and also requires extensive training for its handling, "Chesca said. He also noted that the price of helium-4,
which is a common isotope of helium, is rapidly increasing and its availability may soon be limited to conserve strategic supplies.
and is used already on a daily basis in colleges and universities around the world. Chesca and his colleagues are currently working on optimizing the shape
and design of the SQUID arrays to maximize their magnetic field sensitivity.""The most exciting aspect of our result is that replacing single-SQUIDS operating at 4. 2 K with SQUID arrays operating at 77 K would be, for the first time,
not only a cheaper and more user friendly solution, but a solution that comes with no compromise regarding noise resolution,
Catalysts can split water into its constituent hydrogen and oxygen atoms, a process required for fuel cells.
The latest discovery detailed in Nature Communications, is a significant step toward lower-cost catalysts for energy production,
according to the researchers. hat unique about this paper is that we show not the use of metal particles, not the use of metal nanoparticles,
but the use of atoms, Tour said. he particles doing this chemistry are as small as you can possibly Get even particles on the nanoscale work only at the surface,
he said. here are so many atoms inside the nanoparticle that never do anything. But in our process the atoms driving catalysis have no metal atoms next to them.
Wee getting away with very little cobalt to make a catalyst that nearly matches the best platinum catalysts.
In comparison tests he said the new material nearly matched platinum efficiency to begin reacting at a low onset voltage,
the amount of electricity it needs to begin separating water into hydrogen and oxygen. The new catalyst is mixed as a solution
Tour said single-atom catalysts have been realized in liquids, but rarely on a surface. his way we can build electrodes out of it,
he said. t should be easy to integrate into devices. The researchers discovered that heat-treating graphene oxide and small amounts of cobalt salts in a gaseous environment forced individual cobalt atoms to bind to the material.
Electron microscope images showed cobalt atoms widely dispersed throughout the samples. They tested nitrogen-doped graphene on its own and found it lacked the ability to kick the catalytic process into gear.
But adding cobalt in very small amounts significantly increased its ability to split acidic or basic water. his is an extremely high-performance material,
He noted platinum-carbon catalysts still boast the lowest onset voltage. o question, theye the best.
The technique provides a new approach to modulation that could be useful in all kinds of silicon-based nanoscale devices,
including computer chips and other optoelectronic components.""Our results demonstrate relatively fast modulation from fundamentally slow phosphorescent light emitters,
associate professor of engineering and physics at Brown and senior author of a new paper describing the work."
Phosphors are common light emitters used in light bulbs, LEDS and elsewhere. They are extremely efficient
because much of the energy pumped into them is converted to light as opposed to heat.
But in this latest work, Zia and collaborators, including researchers from Shriram Ramanathan's group at Harvard university,
by rapidly changing the environment around the emitter, "Zia said. The work was led by Sebastien Cueff,
a postdoctoral researcher in Zia's lab. Cueff started with an emitter made of erbium ions,
an important phosphor that is widely used in fiber-optic telecommunication networks. He combined that with a material called vanadium dioxide (VO2.
when pumped with energy, changes very quickly from a transparent insulating state to a reflective metallic state.
This change in reflectivity, in turn, switches how nearby erbium ions emit light. As the VO2 changes phase, the erbium emissions go from being generated mostly by magnetic dipole transitions (the rotational torque push
and pull of magnetic forces), to being generated mostly by electric dipole transitions (the linear push and pull of electric forces).
Those two emission pathways have distinct spectra, and the modulation back and forth between the two can be used as a means to encode information.
One example could be optical communications networks on computer chips. Prototype on-chip networks have used semiconductor lasers as light emitters.
They can modulate very quickly, but they have downsides. Semiconductors can't be grown directly on a silicon chip,
so fabrication can be difficult. Using indirect means of modulation--interferometers, for example--makes for bulky systems that take up a lot of real estate on a chip.
What's more, semiconductor lasers are not particularly efficient. They produce a lot of heat along with light
which is a problem on a silicon chip. Erbium and other phosphors, on the other hand, can be deposited directly on silicon, making fabrication easier.
There's still more work to be done to get such a system up to a speed that would be useful on a chip,
A faster means of changing the VO2 phase--perhaps using electricity instead of a laser--could make the system much faster still.
and industrial researchers working on optoelectronics and nanophotonics, "the researchers write e
#Experimental treatment regimen effective against HIV PROTEASE inhibitors are a class of antiviral drugs that are used commonly to treat HIV, the virus that causes AIDS.
Scientists at the Univ. of Nebraska Medical center designed a new delivery system for these drugs that,
when coupled with a drug developed at the Univ. of Rochester School of medicine and Dentistry, rid immune cells of HIV and kept the virus in check for long periods.
The results appear in the journal Nanomedicine: Nanotechnology, Biology and Medicine. While current HIV treatments involve pills that are taken daily,
the new regimens'long-lasting effects suggest that HIV treatment could be administered perhaps once or twice per year.
and makes it into a crystal, like an ice cube does to water. Next, the crystal drug is placed into a fat and protein coat, similar to
thereby prolonging its therapeutic effect.""The chemical marriage between URMC-099 and antiretroviral drug nanoformulations could increase drug longevity,
improve patient compliance, and reduce general toxicities, "said Gendelman, lead study author and professor and chair of the Department of Pharmacology and Experimental Neuroscience at Nebraska,
who has collaborated with Gelbard for 24 years.""We are excited about pursing this research for the treatment and eradication of HIV infections."
"The two therapies were tested together in laboratory experiments using human immune cells and in mice that were engineered to have a human immune system.
Gendelman and Gelbard believe that the nanoformulation technology helps keep the protease inhibitor in white blood cells longer
and that URMC-099 extends its lifespan even more. Gelbard, director of UR's Center for Neural development and Disease, developed URMC-099 to treat HIV-associated neurocognitive disorders or HAND,
the memory loss and overall mental fog that affects half of all patients living with HIV.
as any patient prescribed URMC-099 would also be taking antiretroviral therapy. The goal was to determine
"Our ultimate hope is that we're able to create a therapy that could be given much less frequently than the daily therapy that is required today,
reduce side effects and help people manage the disease, because they won't have to think about taking medication every day. a
#Snake venom helps hydrogels stop the bleeding A nanofiber hydrogel infused with snake venom may be the best material to stop bleeding quickly, according to Rice Univ. scientists.
and quickly turns into a gel that conforms to the site of a wound, keeping it closed,
Rice chemist Jeffrey Hartgerink, lead author Vivek Kumar and their colleagues reported their discovery in ACS Biomaterials Science and Engineering.
The hydrogel may be most useful for surgeries particularly for patients who take anticoagulant drugs to thin their blood. t interesting that you can take something so deadly
It has been used in various therapies as a way to remove excess fibrin proteins from the blood to treat thrombosis and as a topical hemostat.
an anticoagulant drug. rom a clinical perspective, that far and away the most important issue here, Hartgerink said. here a lot of different things that can trigger blood coagulation,
but when youe on heparin, most of them don work, or they work slowly or poorly.
This is important because surgical bleeding in patients taking heparin can be a serious problem. The use of batroxobin allows us to get around this problem
The substance used for medicine is produced by genetically modified bacteria and then purified, avoiding the risk of other contaminant toxins.
The Rice researchers combined batroxobin with their synthetic, self-assembling nanofibers, which can be loaded into a syringe
and injected at the site of a wound, where they reassemble themselves into a gel.
Tests showed the new material stopped a wound from bleeding in as little as six seconds and further prodding of the wound minutes later did not reopen it.
The researchers also tested several other options: the hydrogel without batroxobin, the batroxobin without the hydrogel, a current clinical hemostat known as Gelfoam and an alternative self-assembling hemostat known as Puramatrix and found that none were as effective, especially in the presence of anticoagulants.
The new work builds upon the Rice lab extensive development of injectable hydrogel scaffolds that help wounds heal
and grow natural tissue. The synthetic scaffolds are built from the peptide sequences to mimic natural processes. o be did clear,
What we did was combine it with the hydrogel wee been working on for a long time. e think SB50 has great potential to stop surgical bleeding, particularly in difficult cases in
Riverside, has found a new and exciting way to elucidate the properties of novel 2-D semiconductors.
Linbo3 is used in many electronic devices dealing with high-frequency signals such as cell phones or radar installations.
the researchers created very high frequency sound waves? surface acoustic waves? that run along the surface of Linbo3, akin to earthquake tremors on land.
Cell phones, for example, use resonances of these surface waves to filter electric signals in a manner similar to a wine glass resonating when a voice hits it at exactly the right pitch.
Specifically, the research team used the surface waves of Linbo3 to listen to how the illumination of Linbo3 by laser light changes the electric properties of Mos2. he tone at
a professor of chemistry who led the team at UC Riverside. n a similar way,
We also fabricated transistor structures onto the Mos2 films and proved that indeed our analysis is correct.
The research project resulted from collaboration between students and researchers at UC Riverside and the Univ. of Augsburg
For this project, Bartels lab greatly benefited from the complementary expertise between the two universities,
followed by device integration in Bavaria. t was really exciting to see how our students obtained these fascinating results by combining the 2-D materials from California
and our expertise in surface acoustic waves, said Hubert Krenner, a member of the Cluster of Excellence Nanosystems Initiative Munich (NIM), Germany,
UCR graduate student Edwin Preciado and Univ. of Augsburg recent graduate Florian J. R. Schülein spearheaded the research project in the research laboratories of Bartels and Krenner
Likewise, Sebastian Hammer, a graduate student at the Univ. of Augsburg, worked in Bartels lab this summer fabricating a new batch of devices in an extension of the current project
#A better way to pack natural gas into fuel tanks A new and innovative way to store methane could speed the development of natural gas-powered cars that don require the high pressures
or cold temperatures of today compressed or liquefied natural gas vehicles. Natural gas is cleaner-burning than gasoline,
and today there are more than 150,000 compressed natural gas (CNG) vehicles on the road in the U s, . most of them trucks and buses. But until manufacturers can find a way to pack more methane into a tank at lower pressures and temperatures,
allowing for a greater driving range and less hassle at the pump, passenger cars are unlikely to adopt natural gas as a fuel.
UC Berkeley chemists have developed now a porous and flexible material so-called metal-organic framework (MOF) or storing methane that addresses these problems.
a UC Berkeley professor of chemistry who led the project. The flexible MOF can be loaded with methane
whereas compressed natural gas (CNG) vehicles compress natural gas into an empty tank under 250 atmospheres (3, 600 psi).
Liquefied natural gas (LNG) vehicles operate at lower pressures but require significant insulation in the tank system to maintain the natural gas at minus-162 degrees Celsius (minus-260 degrees Fahrenheit)
so that it remains liquid. Next-gen NG vehicles Long said that next-generation natural gas vehicles will require a material that binds the methane and packs it more densely into the fuel tank, providing a larger driving range.
One of the major problems has been finding a material that absorbs the methane at a relatively low pressure,
so there is less cooling of the fuel required. f you fill a tank that has adsorbent, such as activated charcoal,
You don have to have as much cooling technology associated with filling your tank. The flexible MOF material could perhaps even be placed inside a balloon-like bag that stretches to accommodate the expanding MOF as methane is pumped in
so that some of the heat given off goes into stretching the bag. Long and his colleagues at the National Institute of Standards and Technology and in Europe will publish their findings online in Nature.
and to produce electricity. It has yet to be adopted widely in the transportation sector, however, because of the expensive and large onboard compressed fuel tanks.
In addition, gasoline packs over three times the energy density per volume as natural gas even when compressed to 3, 600 psi,
which results in natural gas vehicles with a shorter driving range per fill up. In order to advance onboard natural gas storage, Ford motor company teamed up with UC Berkeley on this project, with funding from the Advanced Research Projects Agencynergy (ARPA-E) of the U s. Dept of energy.
Ford is a leader in CNG/propane-prepped vehicles with more than 57,000 sold in the U s. since 2009, more than all other major U s. automakers combined.
According to Mike Veenstra, of Ford research and advanced engineering group in Dearborn Michigan, Ford recognized that ANG has the potential to lower the cost of onboard tanks,
station compressors and fuel along with serving to increase natural gas-powered vehicle driving range within the limited cargo space. atural gas storage in porous materials provides the key advantage of being able to store significant amounts of natural gas at low pressures
than compressed gas at the same conditions, said Veenstra, the principal investigator of this ARPA-E project. he advantage of low pressure is the benefit it provides both onboard the vehicle and off-board at the station.
In addition the low-pressure application facilitates novel concepts such as tanks with reduced wall thicknesses along with conformable concepts
which aid in decreasing the need to achieve the equivalent volumetric capacity of compressed CNG at high pressure.
Long has been exploring MOFS as gas adsorbers for a decade, hoping to use them to capture carbon dioxide emitted from power plants or store hydrogen in hydrogen-fueled vehicles,
or to catalyze gas reactions for industry. Last year, however, a study by UC Berkeley Berend Smit found that rigid MOFS have limited a capacity to store methane.
Long and graduate student and first author Jarad Mason instead turned to flexible MOFS noting that they behave better
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