Posts belonging to Category Universities



Carbon Nanotubes Self-Assemble Into Tiny Transistors

Carbon nanotubes can be used to make very small electronic devices, but they are difficult to handle. University of Groningen (Netherlands) scientists, together with colleagues from the University of Wuppertal and IBM Zurich, have developed a method to select semiconducting nanotubes from a solution and make them self-assemble on a circuit of gold electrodes. The results look deceptively simple: a self-assembled transistor with nearly 100 percent purity and very high electron mobility. But it took ten years to get there. University of Groningen Professor of Photophysics and Optoelectronics Maria Antonietta Loi designed polymers which wrap themselves around specific carbon nanotubes in a solution of mixed tubes. Thiol side chains on the polymer bind the tubes to the gold electrodes, creating the resultant transistor.

polymer wrapped nanotube

In our previous work, we learned a lot about how polymers attach to specific carbon nanotubes, Loi explains. These nanotubes can be depicted as a rolled sheet of graphene, the two-dimensional form of carbon. ‘Depending on the way the sheets are rolled up, they have properties ranging from semiconductor to semi-metallic to metallic.’ Only the semiconductor tubes can be used to fabricate transistors, but the production process always results in a mixture.

We had the idea of using polymers with thiol side chains some time ago‘, says Loi. The idea was that as sulphur binds to metals, it will direct polymer-wrapped nanotubes towards gold electrodes. While Loi was working on the problem, IBM even patented the concept. ‘But there was a big problem in the IBM work: the polymers with thiols also attached to metallic nanotubes and included them in the transistors, which ruined them.’

Loi’s solution was to reduce the thiol content of the polymers, with the assistance of polymer chemists from the University of Wuppertal. ‘What we have now shown is that this concept of bottom-up assembly works: by using polymers with a low concentration of thiols, we can selectively bring semiconducting nanotubes from a solution onto a circuit.’ The sulphur-gold bond is strong, so the nanotubes are firmly fixed: enough even to stay there after sonication of the transistor in organic solvents.

Over the last years, we have created a library of polymers that select semiconducting nanotubes and developed a better understanding of how the structure and composition of the polymers influences which carbon nanotubes they select’, says Loi. The result is a cheap and scalable production method for nanotube electronics. So what is the future for this technology? Loi: ‘It is difficult to predict whether the industry will develop this idea, but we are working on improvements, and this will eventually bring the idea closer to the market.’

The results were published in the journal Advanced Materials on 5 April.
Source: http://www.rug.nl/
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https://www.eurekalert.org/

‘Spray-On’ Memory for Paper, Fabric, Plastic

USB flash drives are already common accessories in offices and college campuses. But thanks to the rise in printable electronics, digital storage devices like these may soon be everywhere – including on our groceries, pill bottles and even clothingDuke University researchers have brought us closer to a future of low-cost, flexible electronics by creating a new “spray-on digital memory device using only an aerosol jet printer and nanoparticle inks. The device, which is analogous to a 4-bit flash drive, is the first fully-printed digital memory that would be suitable for practical use in simple electronics such as environmental sensors or RFID tags. And because it is jet-printed at relatively low temperatures, it could be used to build programmable electronic devices on bendable materials like paper, plastic or fabric.

PrintingMemory

Duke University researchers have developed a new “spray-on” digital memory (upper left) that could be used to build programmable electronics on flexible materials like paper, plastic or fabric. They used LEDS to demonstrate a simple application.

We have all of the parameters that would allow this to be used for a practical application, and we’ve even done our own little demonstration using LEDs,” said Duke graduate student Matthew Catenacci, who describes the device in a paper published online in the Journal of Electronic Materials. At the core of the new device, which is about the size of a postage stamp, is a new copper-nanowire-based printable material that is capable of storing digital information.

Memory is kind of an abstract thing, but essentially it is a series of ones and zeros which you can use to encode information,” said Benjamin Wiley, an associate professor of chemistry at Duke and an author on the paper.

Source: https://today.duke.edu/

Artificial Embryo From Stem Cells

Scientists at the University of Cambridge have managed to create a structure resembling a mouse embryo in culture, using two types of stem cells – the body’s ‘master cells’ – and a 3D scaffold on which they can grow. Understanding the very early stages of embryo development is of interest because this knowledge may help explain why a significant number of human pregnancies fail at this time.

Once a mammalian egg has been fertilised by a sperm, it divides multiple times to generate a small, free-floating ball of stem cells. The particular stem cells that will eventually make the future body, the embryonic stem cells (ESCs) cluster together inside the embryo towards one end: this stage of development is known as the blastocyst. The other two types of stem cell in the blastocyst are the extra-embryonic trophoblast stem cells (TSCs), which will form the placenta, and primitive endoderm stem cells that will form the so-called yolk sac, ensuring that the foetus’s organs develop properly and providing essential nutrients.

Using a combination of genetically-modified mouse ESCs and TSCs, together with a 3D scaffold known as an extracellular matrix, Cambridge researchers were able to grow a structure capable of assembling itself and whose development and architecture very closely resembled the natural embryo.  There is a  remarkable degree of communication between the two types of stem cell: in a sense, the cells are telling each other where in the embryo to place themselves.

artificial embryo

We knew that interactions between the different types of stem cell are important for development, but the striking thing that our new work illustrates is that this is a real partnership – these cells truly guide each other,”  says Professor Zernicka-Goetz. “Without this partnership, the correct development of shape and form and the timely activity of key biological mechanisms doesn’t take place properly.”

Comparing their artificial ‘embryo’ to a normally-developing embryo, the team was able to show that its development followed the same pattern of development. The stem cells organise themselves, with ESCs at one end and TSCs at the other.

The study has been published in the journal Science.

Source: http://www.cam.ac.uk/

NanoCar Race

The NanoCar Race is an event in which molecular machines compete on a nano-sized racetrack. These “NanoCars” or molecule-cars can have real wheels, an actual chassis…and are propelled by the energy of electric pulses! Nothing is visible to the naked eye, however a unique microscope located in Toulouse (France) will make it possible to follow the race. A genuine scientific prowess and international human adventure, the race is a one-off event, and will be broadcast live on the web, as well as at the Quai des Savoirs, science center in Toulouse.

nanocars

The NanoCar race takes place on a very small scale, that of molecules and atoms: the nano scale…as in nanometer! A nanometer is a billionth of a meter, or 0.000000001 meters or 10 -9 m. In short, it is 500,000 times thinner then a line drawn by a ball point pen; 30,000 times thinner than the width of a hair; 100 times smaller than a DNA molecule; 4 atoms of silicon lined up next to one another.

A very powerful microscope is necessary to observe molecules and atoms: the scanning tunneling microscope (STM) makes this possible, and it is also responsible for propelling the NanoCars. The scanning tunneling microscope was invented in 1981 by Gerd Binnig and Heinrich Rohrer, and earned them the Nobel Prize in Physics in 1986. The tunnel effect is a phenomenon in quantum mechanics: using a tip and an electric current, the microscope will use this phenomenon to determine the electric conductance between the tip and the surface, in other words the amount of current that is passing through.

nanocar in movement Screening provides an electronic map of the surface and of each atom or molecule placed on it.At the CNRS‘s Centre d’élaboration de matériaux et d’études structurales (CEMES) in Toulouse, it is the one of a kind STM microscope that makes the race possible: the equivalent of four scanning tunneling microscopes, this device is the only one able to simultaneously and independently map four sections of the track in real time, thanks to its four tungsten tips.

Source: http://nanocar-race.cnrs.fr/

A Brain-computer Interface To Combat The Rise of AI

Elon Musk is attempting to combat the rise of artificial intelligence (AI) with the launch of his latest venture, brain-computer interface company NeuralinkLittle is known about the startup, aside from what has been revealed in a Wall Street Journal report, but says sources have described it as “neural lace” technology that is being engineered by the company to allow humans to seamlessly communicate with technology without the need for an actual, physical interface. The company has also been registered in California as a medical research entity because Neuralink’s initial focus will be on using the described interface to help with the symptoms of chronic conditions, from epilepsy to depression. This is said to be similar to how deep brain stimulation controlled by an implant helps  Matt Eagles, who has Parkinson’s, manage his symptoms effectively. This is far from the first time Musk has shown an interest in merging man and machine. At a Tesla launch in Dubai earlier this year, the billionaire spoke about the need for humans to become cyborgs if we are to survive the rise of artificial intelligence.

cyborg woman

Over time I think we will probably see a closer merger of biological intelligence and digital intelligence,”CNBC reported him as saying at the time. “It’s mostly about the bandwidth, the speed of the connection between your brain and the digital version of yourself, particularly output.” Transhumanism, the enhancement of humanity’s capabilities through science and technology, is already a living reality for many people, to varying degrees. Documentary-maker Rob Spence replaced one of his own eyes with a video camera in 2008; amputees are using prosthetics connected to their own nerves and controlled using electrical signals from the brain; implants are helping tetraplegics regain independence through the BrainGate project.

Former director of the United States Defense Advanced Research Projects Agency (DARPA), Arati Prabhakar, comments: “From my perspective, which embraces a wide swathe of research disciplines, it seems clear that we humans are on a path to a more symbiotic union with our machines.

Source: http://www.wired.co.uk/

Quadriplegic Man Moves Again Just By Thinking

Bill Kochevar grabbed a mug of water, drew it to his lips and drank through the straw. His motions were slow and deliberate, but then Kochevar hadn’t moved his right arm or hand for eight years. And it took some practice to reach and grasp just by thinking about it. Kochevar, who was paralyzed below his shoulders in a bicycling accident, is believed to be the first person with quadriplegia in the world to have arm and hand movements restored with the help of two temporarily implanted technologies.

A brain-computer interface with recording electrodes under his skull, and a functional electrical stimulation (FES) system activating his arm and hand, reconnect his brain to paralyzed muscles. Holding a makeshift handle pierced through a dry sponge, Kochevar scratched the side of his nose with the sponge. He scooped forkfuls of mashed potatoes from a bowl—perhaps his top goal—and savored each mouthful. Kochevar (56, of Cleveland) is the focal point of research led by Case Western Reserve University, the Cleveland Functional Electrical Stimulation (FES) Center at the Louis Stokes Cleveland VA Medical Center and University Hospitals Cleveland Medical Center (UH).


brain implant2

For somebody who’s been injured eight years and couldn’t move, being able to move just that little bit is awesome to me,” said Kochevar. “It’s better than I thought it would be.”

 

He’s really breaking ground for the spinal cord injury community,” commented Bob Kirsch, chair of Case Western Reserve’s Department of Biomedical Engineering, executive director of the FES Center and principal investigator (PI) and senior author of the research. “This is a major step toward restoring some independence.”

A study of the work has been published in the The Lancet.

Source: http://thedaily.case.edu/

Nanocoatings Reduce Dental Implant Bacterial Infection By 97%

According to the American Academy of Implant Dentistry (AAID), 15 million Americans have crown or bridge replacements and three million have dental implants – with this latter number rising by 500,000 a year. The AAID estimates that the value of the American and European market for dental implants will rise to $4.2 billion by 2022. Dental implants are a successful form of treatment for patients, yet according to a study published in 2005, five to ten per cent of all dental implants fail. The reasons for this failure are several-fold – mechanical problems, poor connection to the bones in which they are implanted, infection or rejection. When failure occurs the dental implant must be removed. The main cause for dental implant failure is peri-implantitis. This is the destructive inflammatory process affecting the soft and hard tissues surrounding dental implants. This occurs when pathogenic microbes in the mouth and oral cavity develop into biofilms, which protects them and encourages growth. Peri-implantitis is caused when the biofilms develop on dental implants.

A research team comprising scientists from the School of Biological and Marine Sciences, Peninsula Schools of Medicine and Dentistry and the School of Engineering at the University of Plymouth, have joined forces to develop and evaluate the effectiveness of a new nanocoating for dental implants to reduce the risk of peri-implantitis.

dentistIn this cross-Faculty study we have identified the means to protect dental implants against the most common cause of their failure. The potential of our work for increased patient comfort and satisfaction, and reduced costs, is great and we look forward to translating our findings into clinical practice,”  commented Professor Christopher Tredwin, Head of Plymouth University Peninsula School of Dentistry.

In the study, the research team created a new approach using a combination of silver, titanium oxide and hydroxyapatite nanocoatings. The application of the combination to the surface of titanium alloy implants successfully inhibited bacterial growth and reduced the formation of bacterial biofilm on the surface of the implants by 97.5 per cent.

Not only did the combination result in the effective eradication of infection, it created a surface with anti-biofilm properties which supported successful integration into surrounding bone and accelerated bone healing.

The results of their work are published in the journal Nanotoxicology.

Source: https://www.plymouth.ac.uk/

Clean Renewable Source Of Hydrogen Fuel For Electric Car

Rice University scientists have created an efficient, simple-to-manufacture oxygen-evolution catalyst that pairs well with semiconductors for solar water splitting, the conversion of solar energy to chemical energy in the form of hydrogen and oxygen.

anode RiceA photo shows an array of titanium dioxide nanorods with an even coating of an iron, manganese and phosphorus catalyst. The combination developed by scientists at Rice University and the University of Houston is a highly efficient photoanode for artificial photosynthesis. Click on the image for a larger version

The lab of Kenton Whitmire, a Rice professor of chemistry, teamed up with researchers at the University of Houston and discovered that growing a layer of an active catalyst directly on the surface of a light-absorbing nanorod array produced an artificial photosynthesis material that could split water at the full theoretical potential of the light-absorbing semiconductor with sunlight. An oxygen-evolution  catalyst splits water into hydrogen and oxygen. Finding a clean renewable source of hydrogen fuel is the focus of extensive research, but the technology has not yet been commercialized.

The Rice team came up with a way to combine three of the most abundant metalsiron, manganese and phosphorus — into a precursor that can be deposited directly onto any substrate without damaging it. To demonstrate the material, the lab placed the precursor into its custom chemical vapor deposition (CVD) furnace and used it to coat an array of light-absorbing, semiconducting titanium dioxide nanorods. The combined material, called a photoanode, showed excellent stability while reaching a current density of 10 milliamps per square centimeter, the researchers reported.

The results appear in two new studies. The first, on the creation of the films, appears in Chemistry: A European Journal. The second, which details the creation of photoanodes, appears in ACS Nano.

Source: http://news.rice.edu/

NanoMachine Lifts 15 times Its Weight

Using advanced 3-D printing, Dartmouth College researchers have unlocked the key to transforming microscopic nanorings into smart materials that perform work at human-scaleNanomachines (nanocomputers) can already deliver medication and serve as computer memories at the tiny nanometer scale. By integrating a 3-D printing technique pioneered at Dartmouth’s Ke Functional Materials Group, researchers may unlock even greater potential for these mini-machines.

3D printing nanomachines

A 3-D printed gel structure lifts and lowers a U.S. dime when alternately exposed to water and DMSO solvent

Up until now, harnessing the mechanical work of nanomachines has been extremely difficult. We are slowly getting closer to the point that the tiny machines can operate on a scale that we can see, touch and feel.” said Chenfeng Ke, Assistant Professor for Chemistry at Dartmouth College and principle investigator for the research.

In an example provided by Ke, the first-generation smart material lifted a dime weighing 2.268g. The coin, 15 times the weight of the that lifted it, was raised 1.6 mm– the equivalent of a human lifting a car. “Creating nanomachine-based smart material is still extraordinarily complex and we are only just beginning, but this new technique could allow the design and fabrication of complex smart devices that are currently beyond our grasp,” said Ke.

The research was published on March 22 in the online edition of Angewandte Chemie, the journal of the German Chemical Society.

Source: http://www.keresearchgroup.com/
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http://onlinelibrary.wiley.com/

Cheap, Non-Toxic, Super Efficient Solar Cell

In the future, solar cells can become twice as efficient by employing a few smart little nano-tricks. Researchers are currently developing the environment-friendly solar cells of the future, which will capture twice as much energy as the cells of today. The trick is to combine two different types of solar cells in order to utilize a much greater portion of the sunlight.

solar_nano

These are going to be the world’s most efficient and environment-friendly solar cells. There are currently solar cells that are certainly just as efficient, but they are both expensive and toxic. Furthermore, the materials in our solar cells are readily available in large quantities on Earth. That is an important point,” says Professor Bengt Svensson of the Department of Physics at the University of Oslo (UiO) and Centre for Materials Science and Nanotechnology (SMN) in Norway.

Using nanotechnology, atoms and molecules can be combined into new materials with very special properties. The goal is to utilize even more of the spectrum of sunlight than is possible at present. Ninety-nine per cent of today’s solar cells are made from silicon, which is one of the most common elements on Earth. Unfortunately, silicon solar cells only utilize 20 per cent of the sunlight. The world record is 25 per cent, but these solar cells are laced with rare materials that are also toxic. The theoretical limit is 30 per cent. The explanation for this limit is that silicon cells primarily capture the light waves from the red spectrum of sunlight. That means that most of the light waves remain unutilized.

The new solar cells will be composed of two energy-capturing layers. The first layer will still be composed of silicon cells. “The red wavelengths of sunlight generate electricity in the silicon cells in a highly efficient manner. We’ve done a great deal of work with silicon, so there is only a little more to gain.” The new trick is to add another layer on top of the silicon cells. This layer is composed of copper oxide and is supposed to capture the light waves from the blue spectrum of sunlight.

Source: http://www.apollon.uio.no/

A Smartphone App To Loose Weight

Psychologists at the University of Exeter (UK) have found that less than ten minutes a day of ‘brain training’ using a game they have devised can slow impulses to reach for unhealthy snacks, and reduce calorie intake. Using neuroscience and lab trials to devise a proven method of curbing unhealthy food intake, Professor Natalia Lawrence’s Food Trainer app is being launched this week free to the public, in a month when people traditionally make resolutions to lose weight and cut down on junk foodDr Natalia Lawrence is a cognitive neuroscientist at Exeter University. She designed the app after using brain imaging to study how the brain’s reward system responded to pictures of unhealthy food.

food trainer

It’s very exciting to see that our free and simple training can change eating habits and have a positive impact on some people’s lives,” she said. “It’s a tool to help people make healthier choices. In an age where unhealthy food is so abundant and easily available and obesity is a growing health crisis, we need to design innovative ways to support people to live more healthily. We are optimistic that the way this app is devised will actually encourage people to opt for healthy food such as fruit and vegetables rather than junk food.

Among those to have used the training is Fiona Furness, a studios manager for a charity providing studios for artists, who went from around 11 stone to around nine stone after taking part in a trial of the food training game. She said the “pounds just melted way”. “I used to feel really guilt about my bad snacking habits. I’d often be rushing about, and I’d grab something high calorie and unsatisfying – often a pack of crisps. I’d be hungry again really soon afterwards so it became a vicious cycle. The results have been remarkable,” she explained. “These days, if I am feeling peckish I’ll go for a banana or a pack of almonds. That’s the food I’m craving. I’m now closer to nine stone than 11 – the pounds just melted away over eight or nine months without me even noticing. The weight loss wasn’t really my goal though – I feel younger and more energetic. Perhaps I’m particularly susceptible to this kind of brain training, but it has been transformative for me.

A study of 83 adults showed that people who played the game online just 4 times in one week lost weight and ate an average of 220 kcal less per day – roughly equivalent to a chocolate-iced doughnut.The academics found in trials that playing the game without distractions for a few minutes a day can train the brain to control impulses to reach for chocolate, cakes, crisps or alcohol. The release of the free app will allow dieters or those who want to cut consumption of junk food or alcohol to try it and in the process generate more anonymous data to help psychologists measure how effective an app version of the brain-training programme can be.

The basis of the app is published research showing that people are more inclined to choose foods or drink high in sugar and fat because they activate the brain’s reward system, stimulating the release of dopamine and endorphins, which can produce feelings of pleasure and make the person want more. Research has found that the more people activate brain areas associated with reward when they see foods, the more they eat and the more weight they gain. Once triggered, these impulses can be hard to control.

Source: http://www.exeter.ac.uk/

Virtual Images that Blend In And Interact With The Real-World

Avegant, a Silicon Valley startup that sells a pair of headphones equipped with a VR-like portable screen, is breaking into augmented reality. The company today announced that it’s developed a new type of headset technology powered by a so-called light field display.

Avegant ARCLICK ON THE IMAGE TO ENJOY THE VIDEO

The research prototype, which Avegant eventually plans on turning into a consumer product, is based on the company’s previous work with its Glyph projector. That device was a visor of sorts that floats a virtual movie screen in front of your eyes, and developing it gave Avegant insight into how to build an AR headset of its own.

Like Microsoft’s HoloLens and the supposed prototype from secretive AR startup Magic Leap, Avegant’s new headset creates virtual images that blend in and interact with the real-world environment. In a demo, the company’s wired prototype proved to be superior in key ways to the developer version of the HoloLens. Avegant attributes this not to the power of its tethered PC, but to the device’s light field display — a technology Magic Leap also claims to have developed, yet has never been shown off to the public.

The demo I experienced featured a tour of a virtual Solar System, an immersion within an ocean environment, and a conversation with a virtual life-sized human being standing in the same room. To be fair, Avegant was using a tethered and bulky headset that wasn’t all that comfortable, while the HoloLens developer version is a refined wireless device. Yet with that said, Avegant’s prototype managed to expand the field of view, so you’re looking through a window more the size of a Moleskine notebook instead of a pack of playing cards. The images it produced also felt sharper, richer, and more realistic.

In the Solar System demo, I was able to observe a satellite orbiting an Earth no larger than a bocce ball and identify the Big Red Spot on Jupiter. Avegant constructed its demo to show off how these objects could exist at different focal lengths in a fixed environment — in this case a converted conference room at the company’s Belmont, California office. So I was able to stand behind the Sun and squint until the star went out of focus in one corner of my vision and a virtual Saturn and its rings became crystal clear in the distance.

Source: http://www.theverge.com/