#New technique for'seeing'ions at work in a supercapacitor Researchers from the University of Cambridge, together with French collaborators based in Toulouse,
have developed a new method to see inside battery-like devices known as supercapacitors at the atomic level.
including electric cars, where they can be used alongside batteries to enhance a vehicle performance. By using a combination of nuclear magnetic resonance (NMR) spectroscopy
and tiny scales sensitive enough to detect changes in mass of a millionth of a gram,
the researchers were able to visualise how ions move around in a supercapacitor. They found that
while charging, different processes are at work in the two identical pieces of carbon pongewhich function as the electrodes in these devices, in contrast to earlier computer simulations.
Supercapacitors are used in applications where quick charging and power delivery are important, such as regenerative braking in trains and buses, elevators and cranes.
They are used also in flashes in mobile phones and as a complementary technology to batteries in order to boost performance.
For example when placed alongside a battery in an electric car, a supercapacitor is useful when a short burst of power is required,
such as when overtaking another car, with the battery providing the steady power for highway driving. upercapacitors perform a similar function to batteries
but at a much higher power they charge and discharge very quickly, said Dr John Griffin, a postdoctoral researcher in the Department of chemistry,
and the paper lead author. heye much better at absorbing charge than batteries, but since they have much lower density,
they hold far less of that charge, so theye not yet a viable alternative for many applications.
and that might make them a high-power alternative to batteries. At its most basic level, a battery is made of two metal electrodes (an anode and a cathode) with some sort of solution between them (electrolyte.
When the battery is charged, electrolyte ions are stored in the anode. As the battery discharges, electrolyte ions leave the anode
and move across the battery to chemically react with the cathode. The electrons necessary for this reaction travel through the external circuit,
generating an electric current. A supercapacitor is similar to a battery in that it can generate and store electric current,
but unlike a battery, the storage and release of energy does not involve chemical reactions: instead, positive and negative electrolyte ions simply tickto the surfaces of the electrodes when the supercapacitor is being charged.
When a supercapacitor is being discharged to power a device, the ions can easily opoff the surface
and move back into the electrolyte. The reason why supercapacitors charge and discharge so much faster is that the tickingand oppingprocesses happen much faster than the chemical reactions at work in a battery. o increase the area for ions to stick to,
we fill the carbon electrode with tiny holes, like a carbon sponge, said Griffin. ut it hard to know what the ions are doing inside the holes within the electrode we don know exactly what happens
when they interact with the surface. In the new study, the researchers used NMR to look inside functioning supercapacitor devices to see how they charge and store energy.
They also used a type of tiny weighing scale called an electrochemical quartz crystal microbalance (EQCM) to measure changes in mass as little as a millionth of a gram.
By taking the two sets of information and putting them together, the researchers were able to build a precise picture of
what happens inside a supercapacitor while it charges. n a battery, the two electrodes are different materials,
so different processes are said at work Griffin. n a supercapacitor, the two electrodes are made of the same porous carbon sponge,
so you think the same process would take place at both but it turns out the charge storage process in real devices is complicated more than we previously thought.
Previous theories had been made by computer simulations no one observed this in eal lifebefore. What the experiments showed is that the two electrodes behave differently.
In the negative electrode, there is the expected tickingprocess and the positive ions are attracted to the surface as the supercapacitor charges.
But in the positive electrode, an ion xchangehappens, as negative ions are attracted to the surface, while at the same time,
positive ions are repelled away from the surface. Additionally, the EQCM was used to detect tiny changes in the weight of the electrode as ions enter and leave.
This enabled the researchers to show that solvent molecules also accompany the ions into the electrode as it charges. e can now accurately count the number of ions involved in the charge storage process
and see in detail exactly how the energy is stored, said Griffin. n the future we can look at how changing the size of the holes in the electrode
and the ion properties changes the charging mechanism. This way we can tailor the properties of both components to maximise the amount of energy that is stored.
The next step, said Professor Clare P. Grey, the senior author on the paper, s to use this new approach to understand why different ions behave differently on charging, an ultimately design systems with much higher capacitances. i
#Smart insulin patch could replace injections for diabetes Painful insulin injections could become a thing of the past for the millions of Americans who suffer from diabetes, thanks to a new invention from researchers at North carolina State university and the University
of North carolina at Chapel hill, who have created the first mart insulin patchthat can detect increases in blood sugar levels
and secrete doses of insulin into the bloodstream whenever needed. The patch a thin square no bigger than a penny is covered with more than one hundred tiny needles, each about the size of an eyelash.
These icroneedlesare packed with microscopic storage units for insulin and glucose-sensing enzymes that rapidly release their cargo
when blood sugar levels get too high. The study found that the new, painless patch could lower blood glucose in a mouse model of type 1 diabetes for up to nine hours.
More preclinical tests and subsequent clinical trials in humans will be required before the patch can be administered to patients,
but the approach shows great promise. A paper describing the work is published in the Proceedings of the National Academy of Sciences. e have designed a patch for diabetes that works fast,
is easy to use, and is made from nontoxic, biocompatible materials, said co-senior author Zhen Gu, Phd, a professor in the Joint Department of Biomedical engineering at NC State and UNC-Chapel hill.
Gu also holds appointments in the UNC School of medicine the UNC Eshelman School of Pharmacy, and the UNC Diabetes Care Center. he whole system can be personalized to account for a diabetic weight and sensitivity to insulin,
he added, o we could make the smart patch even smarter. Diabetes affects more than 387 million people worldwide,
and that number is expected to grow to 592 million by the year 2035. Patients with type 1 and advanced type 2 diabetes try to keep their blood sugar levels under control with regular finger pricks and repeated insulin shots, a process that is painful and imprecise.
John Buse MD, Phd, co-senior author of the PNAS paper and the director of the UNC Diabetes Care Center, said,
njecting the wrong amount of medication can lead to significant complications like blindness and limb amputations,
or even more disastrous consequences such as diabetic comas and death. Researchers have tried to remove the potential for human error by creating losed-loop systemsthat directly connect the devices that track blood sugar
and administer insulin. However, these approaches involve mechanical sensors and pumps, with needle-tipped catheters that have to be stuck under the skin
and replaced every few days. Instead of inventing another completely manmade system Gu and his colleagues chose to emulate the body natural insulin generators known as beta cells.
These versatile cells act both as factories and warehouses, making and storing insulin in tiny sacs called vesicles.
They also behave like alarm call centers, sensing increases in blood sugar levels and signaling the release of insulin into the bloodstream. e constructed artificial vesicles to perform these same functions by using two materials that could easily be found in nature,
said PNAS first author Jiching Yu, a Ph d. student in Gu lab. The first material was hyaluronic acid or HA,
a natural substance that is an ingredient of many cosmetics. The second was 2-nitroimidazole or NI,
an organic compound commonly used in diagnostics. The researchers connected the two to create a new molecule,
with one end that was water-loving or hydrophilic and one that was water-fearing or hydrophobic.
A mixture of these molecules self-assembled into a vesicle, much like the coalescing of oil droplets in water,
with the hydrophobic ends pointing inward and the hydrophilic ends pointing outward. The result was millions of bubble-like structures, each 100 times smaller than the width of a human hair.
Into each of these vesicles the researchers inserted a core of solid insulin and enzymes specially designed to sense glucose.
In lab experiments, when blood sugar levels increased, the excess glucose crowded into the artificial vesicles.
The enzymes then converted the glucose into gluconic acid, consuming oxygen all the while. The resulting lack of oxygen or ypoxiamade the hydrophobic NI molecules turn hydrophilic, causing the vesicles to rapidly fall apart
and send insulin into the bloodstream. Once the researchers designed these ntelligent insulin nanoparticles, they had to figure out a way to administer them to patients with diabetes.
Rather than rely on the large needles or catheters that had beleaguered previous approaches, they decided to incorporate these balls of sugar-sensing,
insulin-releasing material into an array of tiny needles. Gu created these icroneedlesusing the same hyaluronic acid that was a chief ingredient of the nanoparticles,
only in a more rigid form so the tiny needles were stiff enough to pierce the skin.
They arranged more than one hundred of these microneedles on a thin silicon strip to create what looks like a tiny, painless version of a bed of nails.
When this patch was placed onto the skin, the microneedles penetrated the surface, tapping into the blood flowing through the capillaries just below.
The researchers tested the ability of this approach to control blood sugar levels in a mouse model of type 1 diabetes.
They gave one set of mice a standard injection of insulin and measured the blood glucose levels,
They also found that the patch did not pose the hazards that insulin injections do.
Injections can send blood sugar plummeting to dangerously low levels when administered too frequently. he hard part of diabetes care is not the insulin shots,
or the blood sugar checks, or the diet but the fact that you have to do them all several times a day every day for the rest of your life,
the director of the North carolina Translational and Clinical Sciences (NC Tracs) Institute and past president of the American Diabetes Association. f we can get these patches to work in people,
#Nanostructure design enables pixels to produce two different colors (Nanowerk News) Through precise structural control,
A*STAR researchers have encoded a single pixel with two distinct colors and have used this capability to generate a three-dimensional stereoscopic image("Three-dimensional plasmonic stereoscopic prints in full colour").
including ultrahigh-definition three-dimensional color displays and state-of-the-art anti-counterfeiting measures. So they set about designing a nanostructure architecture that could provide more bang for the buck. Having previously used plasmonic materials to generate color prints at the optical diffraction limit by carefully varying the nanostructure size and spacing
Yang thought polarization would be a promising direction to pursue. We decided to extend our research to prints that would exhibit different images depending on the polarization of the incident light,
Goh and Yang trialed two aluminum nanostructures as pixel arrays: ellipses and two squares separated by a very small space (known as coupled nanosquare dimers.
Each pixel arrangement had its own pros and cons. While the ellipses offered a broader color range
Furthermore, the researchers used these pixel arrays to generate a three-dimensional stereoscopic image. They achieved this by using ellipses as pixel elements,
carefully offsetting the images and choosing background colors that minimized cross-talk. Being able to print two images onto the same area and,
Complex nanostructures, including circularly asymmetric shapes, offer many more options. By employing additional circular polarizations, we could encode multiple images that is,
#Biomanufacturing of Cds quantum dots A team of Lehigh University engineers have demonstrated a bacterial method for the low-cost, environmentally friendly synthesis of aqueous soluble quantum dot (QD) nanocrystals at room temperature.
along with a team of chemical engineering, bioengineering, and material science students present this novel approach for the reproducible biosynthesis of extracellular,
water-soluble QDS in the July 1 issue of the journal Green Chemistry. This is the first example of engineers harnessing nature's unique ability to achieve cost effective and scalable manufacturing of QDS using a bacterial process.
and cadmium sulfide to provide a route to low-cost, scalable and green synthesis of Cds nanocrystals with extrinsic crystallite size control in the quantum confinement range.
The solution yields extracellular, water-soluble quantum dots from low-cost precursors at ambient temperatures and pressure.
The result is Cds semiconductor nanocrystals with associated size-dependent band gap and photoluminescent properties. This biosynthetic approach provides a viable pathway to realize the promise of green biomanufacturing of these materials.
The Lehigh team presented this process recently to a national showcase of investors and industrial partners at the Techconnect 2015 World Innovation Conference and National Innovation Showcase in Washington
D c. June 14-17.""Biosynthetic QDS will enable the development of an environmentally-friendly, bio-inspired process unlike current approaches that rely on high temperatures, pressures, toxic solvents and expensive precursors,
"Berger says.""We have developed a unique, 'green'approach that substantially reduces both cost and environmental impact."
"Quantum dots, which have use in diverse applications such as medical imaging, lighting, display technologies, solar cells, photocatalysts, renewable energy and optoelectronics, are typically expensive and complicated to manufacture.
In particular, current chemical synthesis methods use high temperatures and toxic solvents, which make environmental remediation expensive and challenging.
This newly described process allows for the manufacturing of quantum dots using an environmentally benign process and at a fraction of the cost.
Whereas in conventional production techniques QDS currently cost $1, 000-$10, 000 per gram, the biomanufacturing technique cuts that cost to about $1-$10 per gram.
The substantial reduction in cost potentially enables large-scale production of QDS viable for use in commercial applications."
"We estimate yields on the order of grams per liter from batch cultures under optimized conditions,
and are able to reproduce a wide size range of Cds QDS, "said Steven Mcintosh.
The research is funded by the National Science Foundation's Division of Emerging Frontiers in Research
and Innovation (EFRI Grant No. 1332349) and builds on the success of the initial funding,
supplied by Lehigh's Faculty Innovation Grant (FIG) and Collaborative Research Opportunity Grant (CORE) programs.
the expansion of this work to include a wide range of other functional materials. Functional materials are controlled those with composition
size, and structure to facilitate desired interactions with light, electrical or magnetic fields, or chemical environment to provide unique functionality in a wide range of applications from energy to medicine.
Mcintosh said, "While biosynthesis of structural materials is established relatively well, harnessing nature to create functional inorganic materials will provide a pathway to a future environmentally friendly biomanufacturing based economy.
We believe that this work is the first step on this path
#Nanoparticle'wrapper'delivers chemical that stops fatty buildup in rodent arteries In what may be a major leap forward in the quest for new treatments of the most common form of cardiovascular disease,
scientists at Johns Hopkins report they have found a way to halt and reverse the progression of atherosclerosis in rodents by loading microscopic nanoparticles with a chemical that restores the animals'ability to properly handle cholesterol.
Cholesterol is a fatty substance that clogs, stiffens and narrows the blood vessels, greatly diminishing their ability to deliver blood to the heart muscle and the brain.
The condition known as atherosclerotic vessel disease, is the leading cause of heart attacks and strokes that claim some 2. 6 million lives a year worldwide, according to the World health organization.
A report on the work, published online in the journal Biomaterials("Improved intervention of atherosclerosis
and cardiac hypertrophy through biodegradable polymer-encapsulated delivery of glycosphingolipid inhibitor), "builds on recent research by the same team that previously identified a fat-and-sugar molecule called GSL as the chief culprit behind a range of biological glitches that affect the body's ability to properly use, transport
and purge itself of vessel-clogging cholesterol. That earlier study showed that animals feasting on high-fat foods remained free of heart disease if pretreated with a man-made compound, D-PDMP,
which works by blocking the synthesis of the mischievous GSL. But the body's natural tendency to rapidly break down
and clear out D-PDMP was a major hurdle in efforts to test its therapeutic potential in larger animals and humans.
The newly published report reveals the scientists appear to have cleared that hurdle by encapsulating D-PDMP into tiny molecules,
which are absorbed faster and linger in the body much longer. In this case, the researchers say,
their experiments show that when encapsulated that way, D-PDMP's potency rose tenfold in animals fed with it.
Most strikingly the team reports, the nano version of the compound was potent enough to halt the progression of atherosclerosis.
but not potent enough to stop the disease from advancing. Perhaps, most importantly, the team says,
and pumping dysfunction, the hallmarks of advanced disease.""Our experiments illustrate clearly that while content is important,
"says lead investigator Subroto Chatterjee, Ph d.,a professor of medicine and pediatrics at the Johns hopkins university School of medicine and a metabolism expert at its Heart and Vascular Institute."
and its ability not merely to prevent disease but to mitigate some of its worst manifestations."
and track the nanoparticles'movement inside the animals'bodies by tagging them with a radioactive tracer that lit up on a CT SCAN.
D-PDMP treatment improved heart function in mice with advanced forms of atherosclerotic heart disease, marked by heart muscle thickening
Because the nanoparticles carrying D-PDMP are made of a common laxative ingredient and a naturally occurring sebacic acid,
#A novel scanning cavity microscope for nanosystems (Nanowerk News) Nanomaterials play an essential role in many areas of daily life.
when particle size falls to the range of a few ten nanometers where a single particle provides only a vanishingly small signal.
The possibility to study the optical properties of individual nanoparticles or macromolecules promises intriguing potential for many areas of biology, chemistry,
and nanoscience (Nature Communications,"A Scanning Cavity Microscope")."Intuitive illustration of the new method for imaging nanoparticles.
Graphic: MPQ, Laser spectroscopy Division) Spectroscopic measurements on large ensembles of nanoparticles suffer from the fact that individual differences in size, shape,
and molecular composition are washed out and only average quantities can be extracted. There is thus a large interest to develop single-particle-sensitive techniques.
Our approach is to trap the probe light used for imaging inside of an optical resonator,
where it circulates tens of thousands of times. This enhances the interaction between the light and the sample,
Because of the resonator, the signal gets enhanced by a factor of 50000. In the microscope, built by Dr. David Hunger and his team,
one side of the resonator is made of a plane mirror that serves at the same time as a carrier for the nanoparticles under investigation.
The counterpart is curved a strongly mirror on the end facet of an optical fibre. Laser light is coupled into the resonator through this fibre.
The plane mirror is moved point by point with respect to the fibre in order to bring the particle step by step into its focus.
For their first measurements, the scientists used gold spheres with a diameter of 40 nanometers.
By combining higher order modes, the scientists could even increase the resolution to around 800 nanometers.
In our experiment we use gold nanorods (34x25x25 nm) and we observe how the resonance frequency shifts depending on the orientation of the polarization.
resulting in two different resonance frequencies for both orthogonal polarizations explains Matthias Mader, Phd student at the experiment.
This birefringence can be measured very precisely and is a very sensitive indicator for the shape and orientation of the particle.
from the characterization of nanomaterials and biological nanosystems to spectroscopy of quantum emitters s
#Sensors and drones: hi-tech sentinels for crops (Nanowerk News) Sensors and drones can be among the farmers'best friends,
helping them to use less fertilizers and water, and to control the general condition of their crops.
Nowadays Piedmont, in north western Italy, is an open air laboratory where companies and research centres are testing these tools to improve the health and productivity of different cultivations.
Such as it happens in the small town of Agliano d'Asti, where the University of Turin,
the research centre CSP and four wine cooperatives are testing a decision support system (DSS) based on wireless sensor networks,
which helps agronomists to verify in real time if plants are enjoying good health. Infrared imagine of an experimental field of wheat in Cigliano, near Vercelli.
Image: University of Turin, Faculty of agriculture) We started about one and a half years ago, explains Andrea Molino,
in charge of the DSS research at CSP, installing in the vineyard five sensors that control the temperature and the humidity of air and soil,
to understand the state of health of the grapevines. Agronomists need to verify if a poor state of health is caused by disease or a lack of water anyway,
but now they have an app for tablets to collect data directly from the field.
In this way, previous data and the data gathered through apps and sensors are channelled into the same database,
says Molino, and it allows facts about different years to be compared. This research has involved also a company based in Ivrea,
and specialized in the use of drones for agriculture: They contribute to the early detection of diseases that affect grapevines,
such as flavescence dore and black wood, declares Stefano Sgrelli, Ceo of Salt&lemon. This is made possible by drones
which carry small cameras able to take near infrared images of crops. Healthy plants are rich in chlorophyll a pigment that reflects infrared quite well:
therefore, this technology, which is used already for scanning by plane, satellite or tractor, has become a precise,
noninvasive and more affordable tool to check how crops are doing. Moreover, it improves sustainability
because it detects whether a plant needs more or less watering, pesticides or plant foods. These sensors give us several indexes,
explains Sgrelli, such as the normalized difference vegetation index, also known as NDVI, which shows the health state of a plant:
the nearer it is to 1, the better the health of the plant. The camera shoots every two or three seconds:
then it needs to adjust the images, because drones normally swing while flying. A software program builds a mosaic made up of hundreds of images,
which shows in a single 3d picture the field flown over. Connecting these results with those gathered by agronomists and sensors on the ground,
the farmer can have a complete overview of what is going on. Even the Piattella bean, cultivated in Cortereggio,
a small town in the Canavese area, has benefited from this technology. The legume is a presidium of Slow food, the global organisation that supports the principles of organic agriculture
reducing pesticides, using traditional techniques and sustaining endangered quality production. The bean was lost almost a crop.
About 25 years ago a farmer, named Mario Boggio, gave some kilos of Piattella to the University of Turins germplasm bank,
to preserve the seed. Twenty years later the cultivation restarted, but the soil was changed. CSP, together with the Association Piattella Canavesana di Cortereggio"and the municipality of San Giorgio Canavese, started monitoring via sensors that control temperature and humidity at 10 and 40 centimetres underground,
and also via near infrared camera. All the data are was sent by digital mobile radio allowing agronomists and farmers to check the results in real time.
Despite the strict parameters that define a Slow food presidium, precision agriculture is a welcome tool: We stand for sustainable agriculture,
so we try to make the most of technology in each case, while of course ensuring that it doesn't infringe human rights
or have long-term environmental effects like GMOS, affirms Ursula Hudson, member of the Executive Committee of Slow food International l
#New device tracks chemical signals within cells Biomedical engineers at the University of Toronto have invented a new device that more quickly
and accurately"listens in on the chemical messages that tell our cells how to multiply. The tool improves our understanding of how cancerous growth begins,
and could identify new targets for cancer medications. Throughout the human body, certain signalling chemicals--known as hormones--tell various cells
when to grow, divide and proliferate. However, not all cells respond to these signals in the same manner.
In rare instances, the internal chemical response of a cell can cause unregulated cell growth
leading to cancer. To look into the responses of different cells, the U of T team harnessed the emerging power of digital microfluidics,
which involves shuttling tiny drops of water around on a series of small electrodes that looks like a miniature checkerboard.
Published today in Nature Communications, the paper explains how they were able to increase the speed at
which chemical changes can be detected by a factor of 100.""By applying the right sequence of voltages,
we can create electric fields that attract and move around droplets containing any chemical solution, "says first author Alphonsus Ng who recently graduated with a Phd from the U of T Institute of Biomaterials and Biomedical engineering (IBBME) and Donnelly Centre,
and is now a postdoctoral fellow in the lab of Professor Aaron Wheeler. Ng and his team's method allows the scientists to deliver a quick-fire sequence of chemicals to small groups of cells stuck to the surface of the board.
For example, the first drop might contain a hormone that tells cells to grow faster. Within seconds
this hormone sets off a chain reaction called a"phosphorylation cascade, "modifying certain proteins within the cell in a specific sequence.
They then deliver a third drop containing fluorescent antibodies that stick only to the proteins modified in the cascade.
Looking at the antibodies in a microscope provides a snapshot of what has changed and what hasn't. By building up a series of snapshots at different time intervals,
scientists can see how the cascade progresses.""It's like a flipboard; each snapshot gives us a static image,
or action,"says Dean Chamberlain, a postdoctoral researcher at IBBME, the Donnelly Centre and the Department of chemistry.
or proteins that could be targeted by drugs, eventually leading to new medicines to fight cancer r
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