Celtic Knot Designs Inspire Polymer Breakthrough

A slow-motion method of controlling the synthesis of polymers, inspired by trees and Celtic Knot designs, could open up new possibilities in areas including medical devices, drug delivery, elastics, and adhesives.

A new slow-motion method of controlling the synthesis of polymers opens up new possibilities in areas including medical devices, drug delivery, elastics and adhesives. (Credit: National University of Ireland, Galway)

Scientists at the Network of Excellence for Functional Biomaterials in the National University of Ireland, Galway, say that their new polymerization technique could be used to create complex, multi-functional, branched compounds, and allow them to tailor polymer properties, such as structure, functionality, strength, size, density and degradation with ease.

The researchers use their technique to build up “Celtic Knots”, materials having chains that only link to themselves in an interlaced pattern. In addition, the new technique can also create hyper-branching polymers, which spread outwards like trees.

They say that for the first time, tree-like polymers can be synthesized in bulk, with branch points after every few monomers of the build process, which allows a far higher degree of branching than previously obtainable, and opens up new possibilities for the use of polymers for biomedical applications such as cross-linkable hydrogel materials and skin adhesives.

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Space Stethoscope Makes Sound Signals Clearer

A team of engineering students at Johns Hopkins University, Baltimore, MD, were challenged to design a new stethoscope to deliver more accurate heart and body sounds for NASA doctors who will be trying to assess astronauts’ health on long missions. In the average spacecraft, much of the ambient noise from fans, computers, and instruments, could interfere with a standard stethoscope’s ability to get a clear signal.

Johns Hopkins mechanical engineering students developed these components for a stethoscope to be used in a noisy space vessel. (Credit: Will Kirk/homewoodphoto.jhu.edu)

The students developed a stethoscope that uses both electronic and mechanical strategies to help the device’s internal microphone pick up sounds that are clear and discernible, even when the device is not placed perfectly correctly on the astronaut’s body. The project was developed during a two-semester mechanical engineering senior design course. The device also includes many other performance-enhancing improvements, including low power consumption, rechargeable batteries, mechanical exclusion of ambient noise, and a suction cup to allow it to adhere to the patient’s chest.

Though developed for use by NASA, the stethoscope could also be used in combat situations, where ambient noise is abundant.

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Robotics Gain Insight from Seahorse Design

Sea horses get their exceptional flexibility from the structure of their bony plates, which form its armor. The plates slide past each other. Here the seahorse’s skeleton, as well as the bony plates, are shown though a micro CT-scan of the animal.

Inspired by the tail of a seahorse, which can be compressed to half its size without damage, scientists at the University of California, San Diego, are attempting to use similar engineering to create a flexible robotic gripper arm equipped with polymer muscles that could be used in medical devices. Led by materials science professors, they say that the study of natural materials can lead to new materials and structures that are stronger, tougher, lighter, and more flexible.

The researchers found that the ridge parts of the tail are the hardest, the plates are free to glide or pivot, and the joints between plates and vertebrae are extremely flexible with nearly six degrees of freedom.

They plan to use 3D printing to create artificial bony plates, which would then be equipped with polymers to act as muscles, and build a robotic arm that would be a unique hybrid between hard and soft robotic devices. The protected, flexible arm would be able to grasp a variety of objects of different shapes and sizes.

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Revolutionary Spray-On Optical Lens Created

Nearly all lenses, whether natural, like the lens in your eye, or man-made, such as in a camera or microscope, are curved, which limits the amount of light that enters. But, using a sprayon technology, a team of researchers made an advancement in flat lens technology that could revolutionize the way optical lenses are made and used.

A sample object placed on a flat slab of the ultraviolet metamaterial, when illuminated with UV light (purple), is projected as a 3D image floating in free space on the other side of the slab. Here a ring-shaped opening in an opaque sheet on the left of the slab is replicated in light on the right. (Credit: Lezec/NIST)

Scientists working at the National Institute of Standards and Technology have demonstrated, for the first time, a new type of lens that bends and focuses ultraviolet light in an unusual way to create ghostly, 3D images of objects that float in space. They say that the easy-to-build lens could lead to improved photolithography, nanoscale manipulation and manufacturing, even high-resolution 3D imaging, and more.

The new lens is formed from a flat slab of metamaterial with special characteristics that cause light to flow backward—a counterintuitive situation in which waves and energy travel in opposite directions, creating a negative refractive index.

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Creating 3D Shapes Using Hand Gestures

Shapes like these can be created using a new design tool that interprets hand gestures, enabling designers and artists to create and modify 3-D shapes using just their hands as a “natural user interface” instead of keyboard and mouse. The tool was created by Purdue researchers. (Credit: Purdue University image/ C Design Lab)

A new design tool that can interpret hand gestures, enables designers at Purdue University, West Lafayette, IN, to create and modify three-dimensional shapes using only their hands as a “natural user interface” instead of using a keyboard and mouse. The tool, called Shape-It-Up, uses specialized computer algorithms and a depth-sensing camera to observe and interpret hand gestures. The user creates shapes in a computer by interacting with a virtual workspace as the shape is displayed and manipulated on a monitor. The creations can then be produced using a 3D printer.

The engineers call the underlying technique shape–gesture–context interplay, and say that the tool could have applications in areas including engineering design, games, architecture, and more.

It uses the Microsoft Kinect camera, which senses 3D space. The researchers created advanced algorithms that recognize hand gestures, understand that the hand is interacting with the shape, and then modify the shape in response to the hand interaction. For more information, visit here.

New Class of Transparent, Stretchable Electrodes Created

This is an LED fitted soft eye contact lens. (Credit: UNIST)

Ulsan National Institute of Science & Technology (UNIST), South Korea, has created contact lenses fitted with inorganic light-emitting diode, and tested them on a live rabbit with no side effects. This new class of hybrid transparent and stretchable electrodes, they say, could pave the way for flexible displays, solar cells, and electronics.

By combining graphene with silver nanowires to form thin, transparent, and stretchable electrodes, the researchers state that this overcame the weaknesses of each individual material, resulting in a new class of electrodes with a wide range of possible applications including picture taking and scanning using soft contact lenses.

The hybrid material presented good electrical and optical performance with mechanical flexibility and stretchability for flexible electronics. The scientists said that there was almost no change in its resistance when bent and folded. And, the hybrid material preserved its electrical and optical properties against thermal oxidation.

In an in vivo study, the contact lens was worn by a rabbit for five hours with no irritation or ill effects observed.

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