#New metamaterial enables refractive index of zero Researchers at the Harvard John A. Paulson School of engineering and Applied sciences (SEAS) say they have made it easier to manipulate light at the nanoscale.
They have developed the first on-chip metamaterial with a refractive index of zero, meaning that the phase of light can travel infinitely fast.
The new metamaterial was developed in the lab of Eric Mazur, the Balkanski Professor of Physics and Applied Physics and Area Dean for Applied Physics AT SEAS,
and is described in the journal Nature Photonics. The metamaterial consists of low-aspect-ratio silicon pillar arrays embedded in a polymer matrix and clad by gold films.
This structure can be fabricated using standard planar processes over a large area in arbitrary shapes and can efficiently couple to photonic integrated circuits
and other optical elements. ight doesn typically like to be squeezed or manipulated but this metamaterial permits us to manipulate light from one chip to another, to squeeze,
bend, twist and reduce diameter of a beam from the macroscale to the nanoscale, said Mazur. his on-chip metamaterial opens the door to exploring the physics of zero index and its applications in integrated optics.
It a remarkable new way to manipulate light. Although this infinitely high velocity seems to break a fundamental rule of relativity
it does not. Besides the absolute speed of light passing from one point to another, light has speed another,
measured by how fast the crests of a wavelength move, known as phase velocity. This speed of light increases or decreases depending on the material it passes through.
what happens when a material refractive index is reduced to zero:""There is no phase advance, meaning light no longer behaves as a moving wave, traveling through space in a series of crests and troughs.
"This uniform phase allows the light to be stretched or squashed, twisted or turned, without losing energy.
A zero-index material that fits on a chip could have exciting applications, especially in the world of quantum computing.
"Integrated photonic circuits are hampered by weak and inefficient optical energy confinement in standard silicon waveguides.
This zero-index metamaterial offers a solution for the confinement of electromagnetic energy in different waveguide configurations
or waveguide to emit photons which are always in phase with one another, "said Philip Munoz,
a graduate student in the Mazur lab and co-author on the paper. t could also improve entanglement between quantum bits,
of those used in volume semiconductor production. In a paper published in the latest issue of Nature Photonics the IMEC
and University of Ghent team describes the development as the irst highly scalable monolithic solutionto a longstanding problem:
the team led by Ghent Dries Van Thourhout suggests that electrical injection-a necessity for true photonic integration-could be achieved readily with the incorporation of a suitable blend of narrow-bandgap semiconductor material in the future.
Van Thourhout and colleagues made an array of distributed feedback (DFB) indium phosphide (Inp) lasers on a 300 mm diameter wafer,
monolithic approach Previous efforts to combine the efficiency of compound semiconductor lasing structures with the scalability of a silicon substrate have focused largely on flip-chipping of prefabricated diodes,
The longstanding challenge has been to find a way to deposit the semiconductor material combination needed for lasing at the 1300 nm
Learning from recent attempts to combine III-V and silicon materials in Finfet electronic devices, the Belgian team grew their laser structures directly onto a standard silicon wafer.
tarting with millimeters-long Inp waveguides of high optical quality grown selectively onto a silicon substrate
including the definition of gratings on top of these waveguides, we fabricated DFB lasers exhibiting robust single-mode operation.
and compound semiconductors is to grow a so-called buffer layer on top of the silicon. But for the particularly large mismatch of Inp and silicon,
the IMEC team was able to produce high-quality Inp waveguides on top of a buffer layer just 20 nm thick.
Although that is not the ideal lasing wavelength for silicon waveguides, and electrical pumping must also be achieved for real applications,
Van Thourhout and colleagues outlined how these challenges could be met. he in-plane laser configuration employed makes it straightforward to adopt well-studied electrical injection schemes,
That approach would allow deposition of the compound semiconductor materials needed to red-shift the lasing wavelength into the telecoms realm at 1300 nm.
it is even possible to envisage butt-coupling the lasers to optical waveguides defined at the same level. n addition,
predicts the team. his also forms a route towards electrical injection for the device. Cutting data center power consumption They suggest that a wide range of applications stand to benefit from the kind of low-cost,
on-chip lasers that could be produced using the approach, concluding that: n particular, for on-chip optical interconnects, the demonstrated monolithic laser array,
together with the WDM technology, may finally pave the way to terascale computing. Photonic integrated circuits (PICS) based on the technology could dramatically change the architecture of fiber-optic transceivers used in data center optical interconnects, by pushing down the cost of chip-level data transfer between logic and memory devices.
That would in turn enable a radical scaling of a data center capacity, while simultaneously reducing increasingly colossal power demands with higher-efficiency data transfer.
According to analysts at the Yole Développement consultancy in France data centers are on track to consume more than 500 TWH of energy annually by 2020
but by implementing new technologies like silicon photonics this total could be cut by at least 10 per cent.
They suggest that the technology could start to feature from 2018 onwards. Importantly, the laser integration work was carried out in IMEC 300mm CMOS pilot line facility,
providing a path to large volume manufacturing and with the potential collaboration of key chip-making partners like Intel, Sony, Samsung and TSMC.
IMEC says that efforts are focused now on growing the more complex semiconductor layer stacks needed for electrical injection of the lasers and emission in the 1300 nm wavelength range d
#3d printed Pills Could Bring Bespoke Drugs to a Hospital Near You It a development that could spell the end of horse pills,
those large pharmaceuticals that seem impossible to swallow. Yesterday, the FDA approved the first drug to be manufactured using 3d printing.
In a buzzword-heavy press release that would make a venture capitalist swoon, Aprecia, the company that makes Spritam, the newly approved drug,
an existing anticonvulsant used to treat epilepsy that has been available as a generic in the U s. since 2008.
Being able to 3d print a tablet offers the potential to create bespoke drugs based on the specific needs of patients,
according to experts. or the last 50 years we have manufactured tablets in factories and shipped them to hospitals
and for the first time this process means we can produce tablets much closer to the patient, said Dr Mohamed Albed Alhnan, a lecturer in pharmaceutics at the University of Central Lancashire.
Today, most bespoke drugs are formulated at specialized compounding pharmacies that are frequently miles away from the hospitals and clinics in
which they are used. 3d printing could bring those capabilities into hospitals and clinics, cutting time off delivery and making custom pharmaceuticals easier to obtain b
#Liquid Water Likely Flows On the Salty Hills of Mars It almost as if our moon turned blood red last night to herald NASA latest Red planet news. At 11:30 EDT,
NASA Headquarters will hold a press conference to discuss their most recent finding: new data that suggests liquid water exists on Mars even today.
This could be the first time in mission history that we have definitive reason to believe there might be microbial life on our closest neighbor.
In 2011, Dr. Mcewen (a planetary geologist at the University of Arizona and principal investigator of images from the Mars Reconnaissance Orbiter) spotted dark streaks sloping down some of Mars canyons and mountains.
#Journey of an adorable hitchhiking robot itchbotended in Philadelphia A social research experimental robot named itchbotwas made by Dr. David Harris Smith of Mcmaster University in Hamilton, Ontario,
and Dr Frauke Zeller Ryerson University, Toronto to explore the streets and make new friends.
This human dependent adorable robot traversed the streets of Canada and Netherlands and made many friendly connections.
It was designed with all the latest equipments like GPS, video and audio, solar panels 3g facilities and foam arms to hug
and shake hand that made it more attractive and helped in socialising. The aim of the robot was to strike off the items from the bucket list by seeking help from the strangers throughout its journey from Salem to San francisco
000 Twitter followers and 48,000 Facebook ikes (Now more than 87,000) The tough town of Philadelphia did not treat the hitchhiking friendly robot so well.
According to Rose Ricciardelli, assistant professor of sociology at Memorial University in Newfoundland, who also authored the study,
According to Michael Cunningham, a psychologist who teaches in the Department of Communication at the University of Louisville,
#New uper-Tomatocan Fight Cancer, Heart disease, Diabetes and Alzheimer Scientists said that they have invented a uper-tomatowhich can fight cancer, heart disease, diabetes and Alzheimer.
The makers of this unique tomato said it has high quantities of disease-fighting antioxidant plant chemicals.
whereas genistein could help in prevention of some cancers, including breast cancer. The study published in the journal Nature Communications said that the super-tomatoes contain a protein called Atmyb12,
which is found in the garden weed thale cress. The researchers said when they introduced the proteins to the tomatoes they acted like opening a tap to boost levels of a group of antioxidants called phenylpropanoids
which are made by plants. Professor Cathie Martin from the John Innes Centre in Norwich said,
ur study provides a general tool for producing valuable phenylpropanoid compounds on an industrial scale in plants
and potentially production of other products derived from aromatic amino acids Martin further said their work could be used effectively in a number of areas including plant and microbe engineering, medicinal plant natural products,
The researchers also hope that the similar technique can be used to manufacture other compounds that form the basis of many medicines a
Researchers say the lab-on-chip device is a step toward creating quantum computers that could help design new drugs,
execute superfast database searches and perform otherwise intractable mathematics calculations that aren't possible for supercomputers.
Developed by a team from the University of Bristol and Nippon Telegraph and Telephone Corp. NTT) in Japan, the fully reprogrammable chip brings together a multitude of existing quantum experiments
and is said to be capable of implementing all possible linear optical protocols up to the size of the circuit.
The system consists of a cascade of 15 Mach-Zehnder interferometers with 30 thermo-optic phase shifters and 12 single-photon detectors.
"A whole field of research has essentially been put onto a single optical chip that is easily controlled,
"The implications of the work go beyond the huge resource savings. Now anybody can run their own experiments with photons,
much like they operate any other piece of software on a computer. They no longer need to convince a physicist to devote many months of their life to painstakingly build
"The team demonstrated the chip's capabilities by programming it to rapidly perform a number of different experiments, each
it took seconds to reprogram the chip, and milliseconds for the chip to switch to the new experiment,"said Jacques Carolan, a doctoral student at Bristol."
"We carried out a year's worth of experiments in a matter of hours. What we're really excited about is using these chips to discover new science that we haven't even thought of yet
#Color-Changing Substance Detects Biological, Mechanical Problems CAMBRIDGE, Mass. Sept. 9, 2015 Responsive to a range of stimuli, a color-changing metallic substance could help detect problems as varied as mechanical strain and pollution.
The material can be engineered to emit specific colors even pure white under different circumstances. In this way the material could be used to detect chemical or biological compounds as well as mechanical and thermal conditions."
"It's supersensitive to external parameters, "said Niels Holten-Andersen, an assistant professor of materials science and engineering at MIT."
"Whatever you do will change the bond dynamics, which will change the color.""Luminescent materials are shown under UV LIGHT,
emitting different colors that can be altered by environmental conditions. Courtesy of Tara Fadenrecht/MIT. The material comprises a metal from the lanthanide group, also known as rare-earth elements,
and a widely used polymer called polyethylene glycol, or PEG. Its light emission can be tailored to reflect very subtle changes in the environment,
providing a color-coded output that reveals details of those conditions. For example, the material could be engineered to detect specific pollutants, toxins or pathogens, with the results instantly visible through color emission.
The material can also detect mechanical changes and could be used to detect stresses in mechanical systems.
The material can be made in a gel, thin film or coating that could be applied to structures,
a professor of chemistry at Duke university who was involved not in this research.""The fact that the reference state can be made white is quite useful;
The findings could help identify ways to repair damaged neural connections in patients with spinal cord injuries or neurodegenerative diseases like amyotrophic lateral sclerosis (ALS), also known as Lou gehrig's disease.
Researchers at the Salk Institute for Biological Studies used a fluorescent tag that could be added to multiple neurons
Observing a mouse spinal cord through a microscope the researchers could watch in real time which cells were activated
"You don't need to do any kind of post-image processing to interpret this, "said Samuel Pfaff, a professor in Salk's Gene expression Laboratory."
"These are just raw signals you can see through the eyepiece of a microscope. It's really a jaw-dropping kind of visualization for a neuroscientist."
That's a key finding for research on how to treat spinal cord injuries and ALS,
Funding for the work came from the National institutes of health, Howard hughes medical institute, Christopher and Dana Reeve Foundation, Sol Goldman Trust and Marshall Heritage Foundation a
. in collaboration with engineers from the University of Bradford and with funding from Innovate U k.,a government funding agency.
Integrated into an injection molding system, the device is capable of generating more than 1. 7 million bar code configurations on anything from cellphones to pills.
The indentations are created by an array of pins that can be set at different heights using microactuators.
"said Dr. Ben Whiteside, a senior lecturer at Bradford.""While our system has been developed initially for products made from plastics or composites through injection molding,
it could also be used to stamp or emboss the code onto a product.""The resulting marks are virtually invisible to the naked eye
and wirelessly transmit the result to mobile devices. The patented technology is already generating interest from the electronics, automotive and pharmaceutical sectors,
where counterfeiting is a serious issue, its developers said. Many pharmaceutical companies are now developing tablets,
produced using an injection molding process, into which 3d bar codes could be incorporated e
#Fiber Sensors Improve Robot Touch Sensitivity Fiber optic sensors could give robots the sensitivity needed to handle delicate objects and work safely alongside humans.
A three-fingered, soft robotic hand features 14 embedded fiber optic strain sensors that enable the hand to determine where its fingertips are in contact
and to detect forces of less than a tenth of a newton. Meanwhile, a new stretchable optical sensing material (which was incorporated not in this version of the hand) could be used in a soft robotic skin to provide even more feedback."
"If you want robots to work autonomously and to react safely to unexpected forces in everyday environments,
you need robotic hands that have more sensors than is said typical today Yong-Lae Park,
an assistant professor of robotics at Carnegie mellon University who led the project.""Human skin contains thousands of tactile sensory units only in the fingertip,
and a spider has hundreds of mechanoreceptors on each leg, but even a state-of-the-art humanoid such as NASA's Robonaut has only 42 sensors in its hand and wrist,
"Park said. The robotic hand was developed in cooperation with Intelligent Fiber optic Systems Corp. of Santa clara, Calif,
It incorporates commercially available fiber Bragg grating sensors, which detect strain by measuring shifts in the wavelength of light propagating through optical fiber.
Conventional pressure or force sensors are problematic because their wiring can be complicated, prone to breaking and susceptible to electromagnetic interference.
Optical fiber, on the other hand, is immune to this interference, and one strand can contain several sensors. All of the sensors in each of the fingers of the robotic hand are connected with four fibers,
although, theoretically, a single fiber could do the job, Park said. Despite their advantages, conventional fiber optic sensors don't stretch much.
Glass fibers stretch hardly at all, and even polymer fibers stretch typically only 20 to 25 percent,
Park said. That is a limiting factor in a device such as a hand where a wide range of motion is essential.
Future versions of the hand could be made even more sensitive with artificial skin that incorporates stretchable fiber sensors based on commercially available silicone rubber.
Also developed in Park's lab, these soft waveguides are lined with reflective gold; as the silicone is stretched,
cracks develop in the reflective layer, allowing light to escape. By measuring the loss of light,
the researchers are able to calculate strain or other deformations. Industrial robots, working in a controlled environment where people aren't present,
are capable of extremely precise manipulation with only limited sensors. But as roboticists work to develop soft robots that can interact routinely and safely with humans,
increased attention to tactile and force sensing is said essential, Park. The work will be presented at the IEEE International Conference on Intelligent Robots and Systems this week in Hamburg
Germany y
#UV Catheter Plugs Holes in Hearts With help from UV LIGHT, a new catheter device could provide a way to repair defects in hearts and other organs without surgery.
The device has already been used successfully in animal studies. It was developed jointly by researchers from Boston Children's Hospital, Harvard university and Brigham and Women's Hospital."
"In addition to avoiding open-heart surgery, this method avoids suturing into the heart tissue, because we're just gluing something to it,
"said Dr. Pedro del Nido, chief of cardiac surgery at Boston Children's Hospital. The catheter is inserted through a vein in the neck or groin and directed to the area of the defect.
Once the catheter is in place, the clinician opens two positioning balloons: one around the front end of the catheter, passing through the hole,
and one on the other side of the organ wall. The clinician then deploys the patch and turns on the catheter's UV LIGHT.
The light reflects off of the balloon's shiny interior and activates the patch's adhesive coating.
As the glue cures, pressure from the balloons secures the patch it in place. Finally, both balloons are deflated
and the catheter is withdrawn. Over time, tissue grows over the patch and it dissolves.""This really is a completely new platform for closing wounds
or holes anywhere in the body,"said Harvard professor Dr. Conor Walsh.""The device is a minimally invasive way to deliver a patch
and then activate it using UV LIGHT, all within a matter of five minutes and in an atraumatic way that doesn't require a separate incision."
"Catheterizations are preferable to open-heart surgery because they don't require stopping the heart, putting the patient on bypass
and cutting into the heart. The biodegradable patch presents its own advantage. While medical devices that remain in the body may be jostled out of place
or fail to cover the hole as the body grows, the patch helps tissue create its own closure.
The rate at which the patch biodegrades can be slowed or accelerated depending on how quickly the surrounding tissue grows over it.
Further studies will reveal the appropriate lengths of time for different circumstances the researchers said.
The adhesive was developed in the lab of Dr. Jeff Karp, a bioengineer at Brigham and Women's Hospital.
The french company Gecko Biomedical, of which Karp is a founder, plans to test the adhesive in humans later this year r
#Camera Offers Hyperspectral Imaging for Consumers A consumer-grade multispectral camera could help users find the best avocado at the grocery store
or allow video games to distinguish between players by the features of their hands. Under development by the University of Washington and Microsoft Research, the Hypercam uses both visible and near-infrared light to peer beneath the surface
and reveal unseen details. Multispectral and hyperspectral cameras used in industrial applications typically cost several thousands to tens of thousands of dollars,
but Hypercam costs about $800 to build. As an add-on to a smartphone camera the cost could go as low as $50,
the developers said. Hypercam is a low-cost multispectral camera developed by the University of Washington
and Microsoft Research that reveals details that are difficult or impossible to see with the naked eye.
Courtesy of the University of Washington. Hypercam illuminates a scene with 17 wavelengths. Software analyzes the resulting images to present the user with the most useful information."
"It mines all the different possible images, and compares it to what a normal camera or the human eye will see
and tries to figure out what scenes look most different, "said Mayank Goel, a University of Washington doctoral student and Microsoft Research graduate fellow.
Compared to an image taken with a normal camera (top), a Hypercam image (bottom) reveals detailed vein and skin texture patterns unique to each individual.
Courtesy of the University of Washington. When Hypercam captured images of a person's hand, for instance,
it revealed detailed vein and skin texture patterns unique to that individual. This could aid in everything from gesture recognition to biometrics to distinguishing between two different people playing the same video game.
To test Hypercam's usefulness as a biometric tool, the developers imaged the hands of 25 different users,
and the system was able differentiate between them with 99 percent accuracy. In another test, the team took multispectral images of 10 different fruits, from strawberries to mangoes to avocados, over the course of a week.
The Hypercam images predicted the relative ripeness of the fruits with 94 percent accuracy, compared with only 62 percent for a typical camera."
"It's not there yet, but the way this hardware was built you can probably imagine putting it in a mobile phone,
"said University of Washington professor Shwetak Patel.""With this kind of camera, you could go to the grocery store
and know what produce to pick by looking underneath the skin and seeing if there's anything wrong inside.
It's like having a food safety app in your pocket.""One challenge is that the technology doesn't work particularly well in bright light,
Goel said. Next research steps will include addressing that problem and making the camera small enough to be incorporated into mobile devices,
he said. The team described its work at the Ubicomp 2015 conference last month in Osaka, Japan n
#Light-Sheet Microscope Pushes Resolution Limits With resolution seven times greater than conventional light-sheet microscopes, an advanced device can capture cell-level 3d images across entire small organisms.
Developed at the Howard hughes medical institute's Janelia Research Campus, the microscope also captures images quickly enough to watch the movement of developing embyronic cells or the flashes of neuronal circuits.
but the most useful data from each image can be combined computationally to generate a final image with good resolution in all dimensions.
The team developed new software capable of processing 10 terabytes of data from one hour of imaging in about two days.
#Antibiotic-Resistant Bacteria Are No Match For Medieval Potion Bloodletting, mercury cures, holes drilled in the headany ancient medical remedies seem ill-advised based on our modern understanding of medicine.
But researchers recently found that a thousand-year-old Anglo-saxon treatment for eye infections works as an antibiotic against one of today most notorious bacteria, Methicillin-resistant Staphylococcus aureus (MRSA.
The british researchers will present their findings this week at an annual microbiology conference held in the United kingdom. Christina Lee,
a professor in Viking studies at the University of Nottingham, translated the recipe from the Old english in Bald Leechbook,
which was written in the 9th century and is one of the earliest known medical textbooks. The researchers prepared four batches of the recipe,
which called for two species of garlic and onions, wine, and bile from a cow stomach brewed in a brass cauldron
and let sit for nine days before use. take cropleek and garlic, of both equal quantities, pound them well together,
let it stand nine days in the brass vessel, wring out through a cloth and clear it well,
The researchers tested the concoction on cultures of MRSA bacteria in synthetic wounds as well as in rats.
like the one in your smartphone, to the brains of blind rats. The rats learned to use the compass to find treats in a maze nearly as well as rats who could see.
Vision is really important to cultivating a sense of where your body is within the surrounding environment.
The electrodes sent electrical pulses to the rats neurons when their heads pointed north and south.
Blind rats without the digital implants never achieved more than a 50 percent chance of guessing the correct branch.
By their fourth day of training, bionic rats chose the correct branch 82 percent of the time,
Overtext Web Module V3.0 Alpha
Copyright Semantic-Knowledge, 1994-2011