Tag Archives: Resolution™

Improving the quality of sight in artificial retinas

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Researchers at France’s Centre national de la recherche scientifique (CNRS) and elsewhere have taken a step forward to improving sight derived from artificial retinas according to an Aug. 25, 2016 news item on Nanowerk (Note: A link has been removed),

A major therapeutic challenge, the retinal prostheses that have been under development during the past ten years can enable some blind subjects to perceive light signals, but the image thus restored is still far from being clear. By comparing in rodents the activity of the visual cortex generated artificially by implants against that produced by “natural sight”, scientists from CNRS, CEA [Commissariat à l’énergie atomique et aux énergies alternatives is the French Alternative Energies and Atomic Energy Commission], INSERM [Institut national de la santé et de la recherche médicale is the French National Institute of Health and Medical Research], AP-HM [Assistance Publique – Hôpitaux de Marseille] and Aix-Marseille Université identified two factors that limit the resolution of prostheses.

Based on these findings, they were able to improve the precision of prosthetic activation. These multidisciplinary efforts, published on 23 August 2016 in eLife (“Probing the functional impact of sub-retinal prosthesis”), thus open the way towards further advances in retinal prostheses that will enhance the quality of life of implanted patients.

An Aug. 24, 2015 CNRS press release, which originated the news item, expands on the theme,

A retinal prosthesis comprises three elements: a camera (inserted in the patient’s spectacles), an electronic microcircuit (which transforms data from the camera into an electrical signal) and a matrix of microscopic electrodes (implanted in the eye in contact with the retina). This prosthesis replaces the photoreceptor cells of the retina: like them, it converts visual information into electrical signals which are then transmitted to the brain via the optic nerve. It can treat blindness caused by a degeneration of retinal photoreceptors, on condition that the optical nerve has remained functional1. Equipped with these implants, patients who were totally blind can recover visual perceptions in the form of light spots, or phosphenes.  Unfortunately, at present, the light signals perceived are not clear enough to recognize faces, read or move about independently.

To understand the resolution limits of the image generated by the prosthesis, and to find ways of optimizing the system, the scientists carried out a large-scale experiment on rodents.  By combining their skills in ophthalmology and the physiology of vision, they compared the response of the visual system of rodents to both natural visual stimuli and those generated by the prosthesis.

Their work showed that the prosthesis activated the visual cortex of the rodent in the correct position and at ranges comparable to those obtained under natural conditions.  However, the extent of the activation was much too great, and its shape was much too elongated.  This deformation was due to two separate phenomena observed at the level of the electrode matrix. Firstly, the scientists observed excessive electrical diffusion: the thin layer of liquid situated between the electrode and the retina passively diffused the electrical stimulus to neighboring nerve cells. And secondly, they detected the unwanted activation of retinal fibers situated close to the cells targeted for stimulation.

Armed with these findings, the scientists were able to improve the properties of the interface between the prosthesis and retina, with the help of specialists in interface physics.  Together, they were able to generate less diffuse currents and significantly improve artificial activation, and hence the performance of the prosthesis.

This lengthy study, because of the range of parameters covered (to study the different positions, types and intensities of signals) and the surgical problems encountered (in inserting the implant and recording the images generated in the animal’s brain) has nevertheless opened the way towards making promising improvements to retinal prostheses for humans.

This work was carried out by scientists from the Institut de Neurosciences de la Timone (CNRS/AMU) and AP-HM, in collaboration with CEA-Leti and the Institut de la Vision (CNRS/Inserm/UPMC).

Artificial retinas

© F. Chavane & S. Roux.

Activation (colored circles at the level of the visual cortex) of the visual system by prosthetic stimulation (in the middle, in red, the insert shows an image of an implanted prosthesis) is greater and more elongated than the activation achieved under natural stimulation (on the left, in yellow). Using a protocol to adapt stimulation (on the right, in green), the size and shape of the activation can be controlled and are more similar to natural visual activation (yellow).

Here’s a link to and a citation for the paper,

Probing the functional impact of sub-retinal prosthesis by Sébastien Roux, Frédéric Matonti, Florent Dupont, Louis Hoffart, Sylvain Takerkart, Serge Picaud, Pascale Pham, and Frédéric Chavane. eLife 2016;5:e12687 DOI: http://dx.doi.org/10.7554/eLife.12687 Published August 23, 2016

This paper appears to be open access.

A new lens (made from nanobeads) for seeing subwavelength images at visible frequencies

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The image which illustrates the research is quite intriguing but I don’t think it makes much sense until you read about the research. From an Aug. 12, 2016 news item on ScienceDaily,

Nanobeads are all around us- and are, some might argue, used too frequently in everything from sun-screen to white paint, but a new ground-breaking application is revealing hidden worlds.

A paper in Science Advances provides proof of a new concept, using new solid 3D superlenses to break through the scale of things previously visible through a microscope.

Illustrating the strength of the new superlens, the scientists describe seeing for the first time, the actual information on the surface of a Blue Ray DVD. That shiny surface is not as smooth as we think. Current microscopes cannot see the grooves containing the data- but now even the data itself is revealed.

Now the image,

(a) Conceptual drawing of nanoparticle-based metamaterial solid immersion lens (mSIL) (b) Lab made mSIL (c) SEM image of 60 nm sized imaging sample (d) corresponding superlens imaging of the 60 nm samples by the developed mSIL. Courtesy: Bangor University

(a) Conceptual drawing of nanoparticle-based metamaterial solid immersion lens (mSIL) (b) Lab made mSIL (c) SEM image of 60 nm sized imaging sample (d) corresponding superlens imaging of the 60 nm samples by the developed mSIL. Credit: ©BangorUniversity Fudan University

An Aug. 13, 2016 Bangor University press release (also on EurekAlert with an Aug. 12, 2016 publication date), which originated the news item, describes the work in more detail,

Led by Dr Zengbo Wang at Bangor University UK and Prof Limin Wu at Fudan University, China, the team created minute droplet-like lens structures on the surface to be examined. These act as an additional lens to magnify the surface features previously invisible to a normal lens.

Made of millions of nanobeads, the spheres break up the light beam. Each bead refracts the light, acting as individual torch-like minute beam. It is the very small size of each beam of light which illuminate the surface, extending the resolving ability of the microscope to record-breaking levels. The new superlens adds 5x magnification on top of existing microscopes.

Extending the limit of classical microscope’s resolution has been the ‘El Dorado’ or ‘Holy Grail’ of microscopy for over a century. Physical laws of light make it impossible to view objects smaller than 200 nm – the smallest size of bacteria, using a normal microscope alone. However, superlenses have been the new goal since the turn of the millennium, with various labs and teams researching different models and materials.

“We’ve used high-index titanium dioxide (TiO2) nanoparticles as the building element of the lens. These nanoparticles are able to bend light to a higher degree than water. To explain, when putting a spoon into a cup of this material, if it were possible, you’d see a larger bend where you spoon enters the material than you would looking at the same spoon in a glass of water,” Dr Wang says.

Nanoparticles splitting single incident beam into multiple=Nanoparticles splitting single incident beam into multiple beams which provides optical super-resolution in imaging.“Each sphere bends the light to a high magnitude and splits the light beam, creating millions of individual beams of light. It is these tiny light beams which enable us to view previously unseen detail.”

Wang believes that the results will be easily replicable and that other labs will soon be adopting the technology and using it for themselves.

The advantages of the technology is that the material, titanium dioxide, is cheap and readily available, and rather than buying a new microscope, the lenses are applied to the material to be viewed, rather than to the microscope.

“We have already viewed details to a far greater level than was previously possible. The next challenge is to adapt the technology for use in biology and medicine. This would not require the current use of a combination of dyes and stains and laser light- which change the samples being viewed. The new lens will be used to see germs and viruses not previously visible.”

Here’s a link to and a citation for the paper,

Three-dimensional all-dielectric metamaterial solid immersion lens for subwavelength imaging at visible frequencies by Wen Fan, Bing Yan, Zengbo Wang, and Limin Wu. Science Advances  12 Aug 2016: Vol. 2, no. 8, e1600901 DOI: 10.1126/sciadv.1600901

This paper is open access.

Coffee-powered athletic gear, courtesy ASICS

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Describing the upcoming collection (2015) of athletic gear from ASICS as coffee-powered is a bit of an exaggeration but at least some of the new gear is derived from coffee beans according to a Sept. 22, 2014 news item on Yahoo Philippines news,

A workout fueled by caffeine, but not in the way you’d guess: Highlights of Asics’ newly announced collection include the patented new textile technology Ecoline, made of repurposed coffee beans which makes for a moisture wicking, breathable polyester.

The entire Sept. 18, 2014 ASICS America press release, available on a Reuters website, which originated the news item, provides more details,

… Exciting standout introductions this season include “ECOLINE®,” a new technology from ASICS utilizing recycled polyester fabric from repurposed coffee beans with sweat-wicking and climate-control benefits, and the new GEL-FujiRunnegade™ running footwear with an anti-gravel tongue to prevent debris from getting into the footwear during off-road runs. No matter the level of competitor or athlete, consumers will find the Spring 2015 collection an unmatched companion in their training, practice, and competition.

The press release doesn’t offer any more details about the repurposed coffee bean-based athletic wear but there is a reference to socks designed with NanoGLIDE® technology which have sweat-wicking and climate control benefits,

… Favorites of ASICS elite tennis athletes like Sam Stosur and Gael Monfils also appear in the collection, including the GEL-Solution® Speed 2, voted “Best Game Day Shoe” by Tennis Magazine, the ASICS Team Performance apparel line and the Resolution™ sock designed for court play with NanoGLIDE®1 technology.

The NanoGLIDE company produces textiles for athletic garments. Here is a bit more information about the socks and the technology from the company’s FAQs (frequently asked questions) page,

Is this technology permanent or a finish?

NanoGLIDE® technology is permanent because it is incorporated into the yarn or fiber from the very beginning of the polyester or nylon fiber manufacturing process. The benefits of the technology will be retained or improved over the life of the garment or sock. Unlike topical finishes, or nano chemistry which are added in the dye bath during fabric finishing or in the wash cycle when socks are laundered before shipping; NanoGLIDE® will not wash off or wear out.

…

What are the benefits of NanoGLIDE® technology when used in apparel and socks?

There is a large demand for performance fabrics and socks that provide multiple benefits in one product. To date, these performance features have largely been obtained through finishing fabrics or washing socks with various chemical additives.

In some cases, there are multiple finishing stages which end up costing additional dollars and sacrificing hand /aesthetics/performance and time. NanoGLIDE® fiber/fabrics were developed to provide multiple attributes (Hand-Loft-Softness-Evaporative Cooling/Moister Management-UV Protection-Friction-Abrasion-Heat Management) that are permanently in the fiber and will not wash out.

Getting back to ASICS and its Ecoline technology, there was an Aug. 2, 2013 press release on Global Newswire.com featuring Ecoline and a coconut-based technology,

Designed for the adventurous trail explorer who demands durable and sustainable clothing to match the elements, a revolutionary addition to the spring 2014 collection is the new Ecoline® fabric with Cocona®1 Technology, which uses natural active particles derived from coconuts and minerals to enhance the performance of the fabrics by increasing breathability, odor management and UV protection.

Whether or not those are nanoparticles being derived from the coconut and minerals is not revealed.