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The Lead

Liquid-crystal-based compound lenses work like insect eyes

May 18, 2015 10:37 am | by Evan Lerner, Univ. of Pennsylvania | Videos | Comments

The compound eyes found in insects and some sea creatures are marvels of evolution. There, thousands of lenses work together to provide sophisticated information without the need for a sophisticated brain. Human artifice can only begin to approximate these naturally self-assembled structures, and, even then, they require painstaking manufacturing techniques.

Researchers develop custom artificial membranes

May 8, 2015 8:06 am | by Evan Lerner, Univ. of Pennsylvania | News | Comments

Decorating the outside of cells like tiny antenna, a diverse community of sugar molecules acts...

Researchers match physical and virtual atomic friction experiments

May 7, 2015 12:00 pm | by Evan Lerner, Univ. of Pennsylvania | News | Comments

Technological limitations have made studying friction on the atomic scale difficult, but...

Engineers invent 2-D liquid

April 2, 2015 11:55 am | by Evan Lerner, Univ. of Pennsylvania | News | Comments

Where water and oil meet, a 2-D world exists. This interface presents a potentially useful set...

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Team discovers new liquid crystal configurations

April 1, 2015 8:08 am | by Evan Lerner, Univ. of Pennsylvania | News | Comments

Oil-based liquid crystals are ubiquitous; an understanding of their properties is behind the displays in most electronics. Water-based liquid crystals are less well understood, though their biocompatibility makes them a candidate for a variety of applications. New research has advanced the field's understanding of these materials, demonstrating never-before-seen configurations by confining a water-based liquid crystal in a cylinder.

Genomewide screen of learning in zebrafish identifies enzyme important in neural circuit

March 23, 2015 11:37 am | by Karen Kreeger, Univ. of Pennsylvania | News | Comments

Researchers at the Univ. of Pennsylvania describe the first set of genes important in learning in a zebrafish model in Neuron. Using in-depth analysis of one of the genes, the team has revealed an important signaling pathway. According to the researchers, the proteins in this pathway could provide new insights into the development of novel pharmacological targets.

Researchers address mysteries behind anti-wear motor oil additive

March 13, 2015 1:41 pm | by Evan Lerner, Univ. of Pennsylvania | News | Comments

The pistons in your car engine rub up against their cylinder walls thousands of times a minute; without lubrication in the form of motor oil, they and other parts of the engine would quickly wear away, causing engine failure. Motor oil contains chemical additives that extend how long engines can run without failure, but, despite decades of ubiquity, how such additives actually work to prevent this damage have remained a mystery.

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New technique developed for making graphene competitor, molybdenum disulphide

February 20, 2015 7:59 am | by Evan Lerner, Univ. of Pennsylvania | News | Comments

Graphene is often touted as a replacement for silicon in electronic devices due to its extremely high conductivity and unbeatable thinness. But graphene isn’t the only 2-D material that could play such a role. Univ. of Pennsylvania researchers have made an advance in manufacturing one such material, molybdenum disulphide.

Research shows way to design digital metamaterials

December 1, 2014 2:39 pm | by Evan Lerner, Univ. of Pennsylvania | Videos | Comments

Metamaterials, precisely designed composite materials that have properties not found in natural ones, could be used to make light-bending invisibility cloaks, flat lenses and other otherwise impossible devices. Figuring out the necessary composition and internal structure to create these unusual effects is a challenge but new research from the Univ. of Pennsylvania presents a way of simplifying things.

Mixing light at the nanoscale

November 17, 2014 3:46 pm | by Evan Lerner, Univ. of Pennsylvania | News | Comments

The race to make computer components smaller and faster and use less power is pushing the limits of the properties of electrons in a material. Photonic systems could eventually replace electronic ones, but the fundamentals of computation, mixing two inputs into a single output, currently require too much space and power when done with light.

Research shows how giant clams harness the sun

October 3, 2014 9:39 am | News | Comments

Beneath the waves, many creatures sport iridescent structures that rival what scientists can make in the laboratory. A research team has now shown how giant clams use these structures to thrive, operating as exceedingly efficient, living greenhouses that grow symbiotic algae as a source of food. This understanding could have implications for alternative energy research, paving the way for new solar panels or improved ways to grow biofuel.

Engineers advance understanding of graphene’s friction properties

September 8, 2014 8:09 am | News | Comments

On the macroscale, adding fluorine atoms to carbon-based materials makes for water-repellant, non-stick surfaces, such as Teflon. However, on the nanoscale, adding fluorine to graphene vastly increased the friction experienced when sliding against the material. Through a combination of physical experiments and atomistic simulations, a Univ. of Pennsylvania research team has discovered the mechanism behind this surprising finding.

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Understanding graphene’s electrical properties on an atomic level

July 22, 2014 7:38 am | by Evan Lerner, Univ. of Pennsylvania | Videos | Comments

Graphene, a material that consists of a lattice of carbon atoms, one atom thick, is widely touted as being the most electrically conductive material ever studied. However, not all graphene is the same. With so few atoms comprising the entirety of the material, the arrangement of each one has an impact on its overall function.

Research develops “onion” vesicles for drug delivery

June 10, 2014 11:22 am | by Evan Lerner, Univ. of Pennsylvania | News | Comments

One of the defining features of cells is their membranes. Each cell’s repository of DNA and protein-making machinery must be kept stable and secure from invaders and toxins. Scientists have attempted to replicate these properties, but, despite decades of research, even the most basic membrane structures, known as vesicles, still face many problems when made in the laboratory.

The motion of the medium matters for self-assembling particles

April 10, 2014 8:16 am | by Evan Lerner, Univ. of Pennsylvania | News | Comments

By attaching short sequences of single-stranded DNA to nanoscale building blocks, researchers can design structures that can effectively build themselves. The building blocks that are meant to connect have complementary DNA sequences on their surfaces, ensuring only the correct pieces bind together as they jostle into one another while suspended in a test tube.

New gel permits targeted therapy after heart attack

April 1, 2014 8:17 am | News | Comments

Combatting the tissue degrading enzymes that cause lasting damage following a heart attack is tricky. Each patient responds to a heart attack differently and damage can vary from one part of the heart muscle to another, but existing treatments can’t be fine-tuned to deal with this variation. Univ. of Pennsylvania researchers have developed a way to address this problem via a material that can be applied directly to the damaged heart tissue.

Researchers “design for failure” with model material

February 24, 2014 11:02 am | News | Comments

When deciding what materials to use in building something, determining how those materials respond to stress and strain is often the first task. A material’s macroscopic, or bulk, properties in this area is generally the product of what is happening on a microscopic scale. When stress causes a material’s constituent molecules to rearrange in a way such that they can't go back to their original positions, it is known as plastic deformation.

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Geophysicist teams with mathematicians to describe how river rocks round

February 13, 2014 10:27 am | News | Comments

For centuries, geologists have recognized that the rocks that line riverbeds tend to be smaller and rounder further downstream. But these experts have not agreed on the reason these patterns exist. Does abrasion reduce the size of rocks significantly, or is it that smaller rocks are simply more easily transported downstream? A new study has arrived at a resolution to this puzzle.

Optogenetic toolkit goes multicolor

February 10, 2014 7:39 am | News | Comments

Optogenetics allows scientists to control neurons’ electrical activity with light by engineering them to express light-sensitive proteins, called opsins. Most opsins respond to light in the blue-green range. Now, a team has discovered an opsin that is sensitive to red light, which allows researchers to independently control the activity of two populations of neurons at once, enabling much more complex studies of brain function.  

Tweaking MRI to track creatine may spot heart problems earlier

January 13, 2014 10:41 am | News | Comments

A new MRI method to map creatine at higher resolutions in the heart may help clinicians and scientists find abnormalities and disorders earlier than traditional diagnostic methods, researchers at the Univ. of Pennsylvania suggest in a recent study. The preclinical findings show an advantage over less sensitive tests and point to a safer and more cost-effective approach than those with radioactive or contrasting agents.

Research lays out theory for metamaterial that acts as an analog computer

January 10, 2014 8:39 am | News | Comments

The field of metamaterials has produced structures with unprecedented abilities, including flat lenses, invisibility cloaks and even optical metatronic devices that can manipulate light in the way electronic circuitry manipulates the flow of electrons.  Now, the birthplace of the digital computer, ENIAC, is using this technology in the rebirth of analog computing.

Researchers grow liquid crystal “flowers” that can be used as lenses

December 23, 2013 11:17 am | News | Comments

In earlier studies, a team from the Univ. of Pennsylvania produced nanoscale grids and rings of “defects,” or useful disruptions in the repeating patterns found in liquid crystals. Their latest study adds a more complex pattern out of an even simpler template: A 3-D array in the shape of a flower. This advances the use of liquid crystals as a medium for assembling structures.

Team identifies mechanism of cancer spread

December 13, 2013 9:59 am | News | Comments

Cancer involves a breakdown of normal cell behavior. Cell reproduction and movement go haywire, causing tumors to grow and spread through the body. A new finding by Univ. of Pennsylvania scientists has identified key steps that trigger this disintegration of cellular regulation. Their discovery—that a protein called Exo70 has a split personality—points to new possibilities for diagnosing cancer metastasis.

New material could make solar panels cheaper, more efficient

December 11, 2013 3:10 pm | News | Comments

A unique solar panel design made with a new ceramic material points the way to potentially providing sustainable power cheaper, more efficiently, and requiring less manufacturing time. It also reaches a four-decade-old goal of discovering a bulk photovoltaic material that can harness energy from visible and infrared light, not just ultraviolet light.

Researchers uncover mechanism behind blood stem cells’ longevity

November 26, 2013 11:38 am | News | Comments

The blood stem cells that live in bone marrow are at the top of a complex family tree. Such stem cells split and divide down various pathways that ultimately produce red cells, white cells and platelets. These “daughter” cells must be produced at a rate of about one million per second to constantly replenish the body’s blood supply. Researchers have long wondered what allows these stem cells to persist for decades, until now.

Team demonstrates new paradigm for solar cell construction

November 12, 2013 8:53 am | News | Comments

Researchers from the Univ. of Pennsylvania and Drexel Univ. have experimentally demonstrated a new method for solar cell construction which may ultimately make them less expensive, easier to manufacture and more efficient at harvesting energy from the sun. The breakthrough, which is the result of five years of focused research, relies on specifically designed perovskite crystals that deliver a “bulk” photovoltaic effect.

New method for harvesting energy from light

September 10, 2013 7:42 am | News | Comments

Researchers from the Univ. of Pennsylvania have demonstrated a new mechanism for extracting energy from light, a finding that could improve technologies for generating electricity from solar energy and lead to more efficient optoelectronic devices used in communications.

Computer model to help design flexible touchscreens

September 4, 2013 7:33 am | News | Comments

Electronic devices with touchscreens rely on transparent conductors made of indium tin oxide, or ITO. But cost and the physical limitations of this material are limiting progress in developing flexible touchscreens. A research collaboration between the Univ. of Pennsylvania and Duke Univ. is exploring the use of nanowires to replace ITO, and are using simulation tools to determine how they might work.

Researchers set the stage for “programmable matter” using nanocrystals

July 29, 2013 9:56 am | News | Comments

Nanoscientists who recently created beautiful, tiled patterns with flat nanocrystals faced a mystery: Why did crystals arrange themselves in an alternating, herringbone style, even though it wasn’t the simplest pattern? Help from computer simulations have given them a new tool for controlling how objects one-millionth the size of a grain of sand arrange themselves into useful materials.

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