Articles from January 2014



New Nanomaterials From CO2

In common perception, carbon dioxide is just a greenhouse gas, one of the major environmental problems of mankind. Carbon dioxide (CO2) is a natural component of Earth’s atmosphere. It is the most abundant carbon-based building block, and is involved in the synthesis of glucose, an energy carrier and building unit of paramount importance for living organisms. For Warsaw chemists CO2 became, however, something else: a key element of reactions allowing for creation of nanomaterials with unprecedented properties. In reaction with carbon dioxide, appropriately designed chemicals allowed researchers from the Institute of Physical Chemistry of the Polish Academy of Sciences (IPC PAS) in Warsaw and the Faculty of Chemistry, Warsaw University of Technology, (WUT) for production of unprecedented nanomaterials.
The novel materials are highly porous, and in their class they show the most extended, and so the largest surface area, which is of key importance for the envisaged use. Prospective applications include storage of energetically important gases, catalysis or sensing devices. Moreover, microporous fluorescent materials obtained using CO2 emit light with quantum yield significantly higher than those of classical materials used in OLEDs.

carbon dioxyde.2jpgYellow tennis balls symbolise crystal lattice of the microporous material resulting from self-assembly of nanoclusters. Orange balls imitate gas molecules that can adsorb in this material. The presentation is performed
Our research is not confined to fabrication of materials. Its particular importance comes from the fact that it opens a new synthetic route to metal carbonate and metal oxide based nanomaterials, the route where carbon dioxide plays a key role”, notices Prof. Janusz Lewiński (IPC PAS, WUT).
Carbon dioxide has been for years used in industrial synthesis of polymers. On the other hand, there has been very few research papers reporting fabrication of inorganic functional materials using CO2”, says Kamil Sokołowski, a doctoral student in IPC PAS.

The papers reporting accomplishments of Prof. Lewiński’s group, achieved in cooperation with Cambridge University and University of Nottingham, were published, i.a., by journals “Angewandte Chemie” and “Chemical Communications”.
Source: http://www.ichf.edu.pl/

Gecko Robots To Repair Ships In The Deep Space

The sticky feet of a climbing, gecko-like robot developed by Simon Fraser University ( SFU ) – Canada – researchers could be useful in space. The SFU research was recently tested in the labs of the European Space Agency (ESA), which has co-sponsored the project since 2008.
SFU engineering scientist Carlo Menon says his team developed techniques similar to those used in the microelectronics industry to create “footpad terminators” much like the nanoscopic hairs on a gecko’s feet. A dry adhesive created to complete the process was then tested in space-like conditions.

Sticky feet robot

The climbing robot, dubbed Abigaille, features six legs, each with four degrees of freedom for optimum agility, allowing the robot to get around obstacles by crawling vertically or horizontally.
The research has involved multiple SFU undergraduate, master’s and PhD students, as well as postdoctoral fellows. Former master’s student Michael Henrey carried out testing of the robots in ESA’s Electrical Materials and Process Lab in the Netherlands.
The ESA has issued a news release about the testing and Menon will have a paper published this month in the Journal of Bionic Engineering.

Source: http://www.sfu.ca/

Vaginal Cream Blocks HIV Up To 72 Hours

The product has proven efficiency in lab tests, although clinical trials are yet to be performed. After discovering that silver nanoparticles are capable of blocking the entry of Human Immunodeficiency Virus (HIV) into the organism, a group of researchers from the University of Texas, in collaboration with Humberto Lara Villegas, specialist in nanoparticles and virology from the University of Monterrey, Mexico (UDEM), create a vaginal cream to control the transmition of the virus. Lara Villegas explained that HIV makes its entry to immune cells (CD4) of the organism with the aid of a protein known as GP120, which allows the virus adherence to the cells. This same principle is used by silver nanoparticles to attach themselves to this protein and block it, turning the virus inactive. The Mexican researcher informed that the cream has been tested in samples of human tissue and has proven the efficiency of silver nanoparticles to avoid the transmition of the virus through cervical mucous membrane. The researcher from UDEM, who has worked in Israel and The United States, assured that after applied, the cream starts to work in less than a minute, and has an effective protection of up to 72 hours. Given that the function of this product is the inactivation of the virus, although this is a vaginal cream, will also protect the sexual partner.
silver nanoparticles

Normally – he highlighted-, the medication used against the virus act within the cell to avoid its replication. This is a very different case, given that the nanoparticle goes directly against the HIV and no longer allows its entry to the cell”. “Right now, I am certain that this microbicide is going to avoid the virus entering the organism, but I cannot yet assure that is totally harmless, because the clinical trials are a long and expensive process”, the researcher added.
Source: http://www.alphagalileo.org/

Lungs May Be Attacked By Nanoparticles

Nanoparticles are used in all kinds of applications — electronics, medicine, cosmetics, even environmental clean-ups. More than 2,800 commercially available applications are now based on nanoparticles, and by 2017, the field is expected to bring in nearly $50 billion worldwide.
But this influx of nanotechnology is not without risks, say researchers at Missouri University of Science and Technology.
There is an urgent need to investigate the potential impact of nanoparticles on health and the environment,” says Yue-Wern Huang, professor of biological sciences at Missouri S&T.
Huang and his colleagues have been systematically studying the effects of transition metal oxide nanoparticles on human lung cells. These nanoparticles are used extensively in optical and recording devices, water purification systems, cosmetics and skin care products, and targeted drug delivery, among other applications.


In their typical coarse powder form, the toxicity of these substances is not dramatic,” says Huang. “But as nanoparticles with diameters of only 16-80 nanometers, the situation changes significantly.
About 80 percent of the cells died in the presence of nanoparticles of copper oxide and zinc oxide,” says Huang. “These nanoparticles penetrated the cells and destroyed their membranes. The toxic effects are related to the nanoparticles’ surface electrical charge and available docking sites.”
Huang says that certain nanoparticles released metal ions — called ion dissolution — which also played a significant role in cell death.

Source: http://news.mst.edu/

How To Fix Damaged Hearts

In the U.S., someone suffers a heart attack every 34 seconds — their heart is starved of oxygen and suffers irreparable damage. Engineering new heart tissue in the laboratory that could eventually be implanted into patients could help, and scientists are reporting a promising approach tested with rat cells.

Gordana Vunjak-Novakovic, Rui L. Reis, Ana Martins and colleagues point out that when damaged, adult heart tissue can’t heal itself very well. The only way to fix an injured heart is with a transplant. But within the past decade, interest in regenerating just the lost tissue has surged. The trick is to find materials that, among other things, are nontoxic, won’t get attacked by the body’s immune system and allow for muscle cells to pass the electrical signals necessary for the heart to beat. Previous research has found that chitosan, which is obtained from shrimp and other crustacean shells, nearly fits the bill. In lab tests, scientists have used it as a scaffold for growing heart cells. But it doesn’t transmit electrical signals well. Vunjak-Novakovic’s team decided to build on the chitosan development and coax it to function more like a real heart.
heart
To the chitosan, they added carbon nanofibers, which can conduct electricity, and grew neonatal rat heart cells on the resulting scaffold. After two weeks, cells had filled all the pores and showed far better metabolic and electrical activity than with a chitosan scaffold alone. The cells on the chitosan/carbon scaffold also expressed cardiac genes at higher levels.
The findings have been published in the ACS journal Biomacromolecules.
Source: http://www.eurekalert.org/

In the U.S., someone suffers a heart attack every 34 seconds — their heart is starved of oxygen and suffers irreparable damage. Engineering new heart tissue in the laboratory that could eventually be implanted into patients could help, and scientists are reporting a promising approach tested with rat cells. They published their results on growing cardiac muscle using a scaffold containing carbon nanofibers in the ACS journal Biomacromolecules.

Gordana Vunjak-Novakovic, Rui L. Reis, Ana Martins and colleagues point out that when damaged, adult heart tissue can’t heal itself very well. The only way to fix an injured heart is with a transplant. But within the past decade, interest in regenerating just the lost tissue has surged. The trick is to find materials that, among other things, are nontoxic, won’t get attacked by the body’s immune system and allow for muscle cells to pass the electrical signals necessary for the heart to beat. Previous research has found that chitosan, which is obtained from shrimp and other crustacean shells, nearly fits the bill. In lab tests, scientists have used it as a scaffold for growing heart cells. But it doesn’t transmit electrical signals well. Vunjak-Novakovic’s team decided to build on the chitosan development and coax it to function more like a real heart.

To the chitosan, they added carbon nanofibers, which can conduct electricity, and grew neonatal rat heart cells on the resulting scaffold. After two weeks, cells had filled all the pores and showed far better metabolic and electrical activity than with a chitosan scaffold alone. The cells on the chitosan/carbon scaffold also expressed cardiac genes at higher levels.

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See-through Screen On Ordinary Glass

Transparent displays have a variety of potential applications — such as the ability to see navigation or dashboard information while looking through the windshield of a car or plane, or to project video onto a window or a pair of eyeglasses. A number of technologies have been developed for such displays, but all have limitations.
Now, researchers at MIT have come up with a new approach that can have significant advantages over existing systems, at least for certain kinds of applications: a wide viewing angle, simplicity of manufacture, and potentially low cost and scalability.

The innovative system is described in a paper published this week in the journal Nature Communications, co-authored by MIT professors Marin Soljačić and John Joannopoulos, graduate student Chia Wei Hsu, and four others.
MIT_transparent_display-590x330The glass will look almost perfectly transparent,” Soljačić says, “because most light is not of that precise wavelength” that the nanoparticles are designed to scatter. That scattering allows the projected image to be seen in much the same way that smoke in the air can reveal the presence of a laser beam passing through it.

Source: http://web.mit.edu/

Highly Sensitive Whiskers For Robots

From the world of nanotechnology we’ve gotten electronic skin, or e-skin, and electronic eye implants or e-eyes. Now we’re on the verge of electronic whiskers. Researchers with Berkeley Lab and the University of California (UC) Berkeley have created tactile sensors from composite films of carbon nanotubes and silver nanoparticles similar to the highly sensitive whiskers of cats and rats. These new e-whiskers respond to pressure as slight as a single Pascal, about the pressure exerted on a table surface by a dollar bill. Among their many potential applications is giving robots new abilities to “see” and “feel” their surrounding environment.
whiskers

E-whiskers are highly responsive tactile sensor networks made from carbon nanotubes and silver nanoparticles that resemble the whiskers of cats and other mammals
Whiskers are hair-like tactile sensors used by certain mammals and insects to monitor wind and navigate around obstacles in tight spaces,” says the leader of this research Ali Javey, a faculty scientist in Berkeley Lab’s Materials Sciences Division and a UC Berkeley professor of electrical engineering and computer science. “Our electronic whiskers consist of high-aspect-ratio elastic fibers coated with conductive composite films of nanotubes and nanoparticles. In tests, these whiskers were 10 times more sensitive to pressure than all previously reported capacitive or resistive pressure sensors.”

Source: http://newscenter.lbl.gov/

How To Protect Laptops From Heat Generation

As smartphones, tablets and other gadgets become smaller and more sophisticated, the heat they generate while in use increases. This is a growing problem because it can cause the electronics inside the gadgets to fail. Conventional wisdom suggests the solution is to keep the guts of these gadgets cool. But a new University at Buffalo research paper hints at the opposite: that is, to make laptops and other portable electronic devices more robust, more heat might be the answer.
electric current in a narrow channel

Electric current in a narrow channel

We’ve found that it’s possible to protect nanoelectronic devices from the heat they generate in a way that preserves how these devices function,” said Jonathan Bird, UB professor of electrical engineering. “This will hopefully allow us to continue developing more powerful smartphones, tablets and other devices without having a fundamental meltdown in their operation due to overheating.”
The paper, “Formation of a protected sub-band for conduction in quantum point contacts under extreme biasing,” was published Jan. 19 in the journal Nature Nanotechnology. It is available at the following link:
http://bit.ly/1ikkkHg.
Source: http://www.buffalo.edu/

How To Reduce Recurrent Heart Attacks

Icahn School of Medicine at Mount Sinai designs a high-density lipoprotein HDL – nanoparticle to deliver statin medication inside inflamed blood vessels to prevent repeat heart attacks and stroke.
Mount Sinai‘s novel HDL nanoparticle (red), loaded with a statin drug, specifically targets and locally treats inflammatory macrophage cells (green) hiding inside high-risk plaque within blood vessels.
Up to 30 percent of heart attack patients suffer a new heart attack because cardiologists are unable to control inflammation inside heart arteries — the process that leads to clots rupturing and causing myocardial infarction or stroke.

In mouse studies, they show this HDL nanotherapy is capable of directly targeting and lowering dangerous inflammation in blood vessels.
Not only could the HDL nanotherapy potentially avert repeat heart attacks, it may also have the power to reduce recurrent strokes caused by clots in brain arteries, says the study’s senior investigator, Willem Mulder, PhD, Associate Professor of Radiology in the Translational and Molecular Imaging Institute at the Icahn School of Medicine at Mount Sinai.

HDL nanoparticleMount Sinai’s novel HDL nanoparticle (red), loaded with a statin drug, specifically targets and locally treats inflammatory macrophage cells (green) hiding inside high-risk plaque within blood vessels.
We envision that a safe and effective HDL nanotherapy could substantially lower cardiovascular events during the critical period of vulnerability after a heart attack or stroke,” says Dr. Mulder.
While we have much more to do to confirm clinical benefit in patients, our study shows how this nanotherapy functions biologically, and how this novel concept could potentially also work in the clinical setting to solve a critical problem”, he added. “This nanotherapy would be the first of its kind.”

Source; http://icahn.mssm.edu/

How To Tap The Sun’s Energy Through Heat

A new approach to harvesting solar energy, developed by MIT researchers, could improve efficiency by using sunlight to heat a high-temperature material whose infrared radiation would then be collected by a conventional photovoltaic cell. This technique could also make it easier to store the energy for later use, the researchers say. In this case, adding the extra step improves performance, because it makes it possible to take advantage of wavelengths of light that ordinarily go to waste.

A conventional silicon-based solar celldoesn’t take advantage of all the photons,” explains associate professor of mechanical engineering Evelyn Wang,. That’s because converting the energy of a photon into electricity requires that the photon’s energy level match that of a characteristic of the photovoltaic (PV) material called a bandgap. Silicon’s bandgap responds to many wavelengths of light, but misses many others. This basic concept has been explored for several years, since in theory such solar thermophotovoltaic (STPV) systems could provide a way to circumvent a theoretical limit on the energy-conversion efficiency of semiconductor-based photovoltaic devices. That limit, called the Shockley-Queisser limit, imposes a cap of 33.7 percent on such efficiency, but Wang says that with TPV systems, “the efficiency would be significantly higher — it could ideally be over 80 percent.
nanophotonic solar photovoltaicNanophotonic solar thermophotovoltaic device

Zhuomin Zhang, a professor of mechanical engineering at the Georgia Institute of Technology who was not involved in this research, says, “This work is a breakthrough in solar thermophotovoltaics, which in principle may achieve higher efficiency than conventional solar cells because STPV can take advantage of the whole solar spectrum. … This achievement paves the way for rapidly boosting the STPV efficiency.

The process is described in a paper published this week in the journal Nature Nanotechnology.
Source: http://web.mit.edu/

How To Produce Cheap Hydrogen Fuel

Humans have for ages taken cues from nature to build their own devices, but duplicating the steps in the complicated electronic dance of photosynthesis remains one of the biggest challenges and opportunities for chemists.

Currently, the most efficient methods we have for making fuel – principally, hydrogen – from sunlight and water involve rare and expensive metal catalysts, such as platinum. In a new study, researchers at the U.S. Department of Energy’s Argonne National Laboratory have found a new, more efficient way to link a less expensive synthetic cobalt-containing catalyst to an organic light-sensitive molecule, called a chromophore.
hydrogen-electric car

Although cobalt is significantly less efficient than platinum when it comes to light-induced hydrogen generation, the drastic price difference between the two metals makes cobalt the obvious choice as the foundation for a synthetic catalyst“, said Argonne chemist Karen Mulfort. “Cobalt doesn’t have to be as efficient as platinum because it is just so much cheaper“.

Source; http://www.anl.gov/