A new study by a team of scientists defines previously unknown properties of transmitted HIV-1, the virus that causes AIDS. The viruses that successfully pass from a chronically infected person to a new individual are both remarkably resistant to a powerful initial human immune-response mechanism, and they are blanketed in a greater amount of envelope protein that helps them access and enter host cells.
A dye-based imaging technique known as two-photon microscopy can produce pictures of...
A new study by a team of scientists defines previously unknown properties of...
Certain semiconductors, when imparted with energy, in turn emit light; they directly...
Leading nanoscientists created beautiful, tiled patterns with flat nanocrystals, but they were left with a mystery: Why did some sets of crystals arrange themselves in an alternating, herringbone style? To find out, they turned to experts in computer simulation at the University of Michigan and the Massachusetts Institute of Technology.
The allure of personalized medicine has made new, more efficient ways of sequencing genes a top research priority. One promising technique involves reading DNA bases using changes in electrical current as they are threaded through a nanoscopic hole. Now, a team led by University of Pennsylvania physicists has used solid-state nanopores to differentiate single-stranded DNA molecules containing sequences of a single repeating base.
Beyond serving as the backbone of modern biology, DNA has come to be a molecule of great interest to engineers. That a DNA sequence will naturally bind only with a complementary sequence could make it part of a configurable, and potentially programmable, building material. Researchers at the University of Pennsylvania have now used DNA to make a crystal that can switch into a more stable configuration under the right temperature conditions, much like heat-treated steel.
Wear is a fact of life. As surfaces rub against one another, they break down and lose their original shape. With less material to start with and functionality that often depends critically on shape and surface structure, wear affects nanoscale objects more strongly than it does their macroscale counterparts. Worse, the mechanisms behind wear processes aren't well understood for nanotech devices. Until now.
Last year, a team of University of Pennsylvania physicists showed how to undo the "coffee-ring effect," a commonplace occurrence when drops of liquid with suspended particles dry, leaving a ring-shaped stain at the drop's edges. Now the team is exploring how those particles stack up as they reach the drop's edge, and they discovered that different particles make smoother or rougher deposition profiles at the drop edge depending on their shape.
Directed assembly is a growing field of research in nanotechnology in which scientists and engineers aim to manufacture structures on the smallest scales without having to individually manipulate each component. Rather, they set out precisely defined starting conditions and let the physics and chemistry that govern those components do the rest. An interdisciplinary team of researchers from the University of Pennsylvania has shown a new way to direct the assembly of liquid crystals.
The field of metamaterials involves augmenting materials with specially designed patterns, enabling those materials to manipulate electromagnetic waves and fields in previously impossible ways. Now, researchers from the University of Pennsylvania have come up with a theory for moving this phenomenon onto the quantum scale, laying out blueprints for materials where electrons have nearly zero effective mass.
Electronic circuits are typically integrated in rigid silicon wafers, but flexibility opens up a wide range of applications. In a world where electronics are becoming more pervasive, flexibility is a highly desirable trait, but finding materials with the right mix of performance and manufacturing cost remains a challenge. Now a team of researchers from the University of Pennsylvania has shown that nanocrystals of the semiconductor cadmium selenide can be "printed" or "coated" on flexible plastics to form high-performance electronics.
One of the most promising innovations of nanotechnology has been the ability to perform rapid nanofabrication using nanoscale tips. The fabrication speed can be dramatically increased by using heat. High speed and high temperature have been known to degrade the tip, until now.
Making uniform coatings is a common engineering challenge, and, when working at the nanoscale, even the tiniest cracks or defects can be a big problem. New research from University of Pennsylvania engineers has shown a new way of avoiding such cracks when depositing thin films of nanoparticles based on spin-coating.
The colors of a butterfly's wings are unusually bright and beautiful and are the result of an unusual trait: The way they reflect light is fundamentally different from how color works most of the time. A team of researchers at the University of Pennsylvania has found a way to generate this kind of "structural color" that has the added benefit of another trait of butterfly wings: superhydrophobicity, or the ability to strongly repel water.
Nearly 100 years after a British neurologist first mapped the blind spots caused by missile wounds to the brains of soldiers, University of Pennsylvania scientists have perfected his map using modern-day technology. Their results create a map of vision in the brain based upon an individual's brain structure, even for people who cannot see. Their result could, among other things, guide efforts to restore vision using a neural prosthesis that stimulates the surface of the brain.
Computers may be getting faster every year, but those advances in computer speed could be dwarfed if their 1s and 0s were represented by bursts of light, instead of electricity. Researchers at the University of Pennsylvania have made an important advance in this frontier of photonics, fashioning the first all-optical photonic switch out of cadmium sulfide nanowires.
Many robotic designs take nature as their muse: sticking to walls like geckos, swimming through water like tuna, sprinting across terrain like cheetahs. Such designs borrow properties from nature, using engineered materials and hardware to mimic animals' behavior. Now, scientists at Massachusetts Institute of Technology and the University of Pennsylvania are taking more than inspiration from nature—they're taking ingredients.
Solar panels, like those commonly perched atop house roofs or in sun-drenched fields, quietly harvesting the sun's radiant energy, are one of the standard-bearers of the green energy movement. But could they be better—more efficient, durable, and affordable? That's what engineers from Drexel University and the University of Pennsylvania are trying to find out, with the aid of a little nanotechnology and a lot of mathematical modeling.
Researchers from the University of Pennsylvania, along with collaborators from Italy and Spain, have created a material that catalyzes the burning of methane 30 times better than currently available catalysts. The discovery offers a way to more completely exploit energy from methane, potentially reducing emissions of this greenhouse gas from vehicles that run on natural gas.
University of Pennsylvania researchers have developed an innovative solution to the problem of perfusion, or suffocation, in engineered tissue structures. Recently, they've shown that 3D printed templates of filament networks can be used to rapidly create vasculature and improve the function of engineered living tissues.
Memory devices for computers require a large collection of components that can switch between two states, which represent the 1s and 0s of binary language. Engineers hope to make next-generation chips with materials that distinguish between these states by physically rearranging their atoms into different phases. Researchers at the University of Pennsylvania have now provided new insight into how this phase change happens.
A team of engineers at Stanford University and the University of Pennsylvania has for the first time used plasmonic cloaking to create a device that can see without being seen—an invisible machine that detects light. It is the first example of what the researchers describe as a new class of devices that controls the flow of light at the nanoscale to produce both optical and electronic functions.
Most people take gravity for granted. But for University of Pennsylvania astrophysicist Bhuvnesh Jain, the nature of gravity is the question of a lifetime. As scientists have been able to see farther and deeper into the universe, the laws of gravity have been revealed to be under the influence of an unexplained force. By analyzing a well-studied class of stars in nearby galaxies, a team of astrophysicists have produced new findings that narrow down the possibilities of what this force could be.
A team of biomedical engineers and hematologists at the University of Pennsylvania has made large-scale, patient-specific simulations of blood function under the flow conditions found in blood vessels, using robots to run hundreds of tests on human platelets responding to combinations of activating agents that cause clotting.
Protein design is a technique that is increasingly valuable to a variety of fields, from biochemistry, to therapeutics, to materials engineering. University of Pennsylvania chemists have taken this kind of design a step further; using computational methods, they have created the first custom-designed protein crystal.
An ambitious new project to reinvent how robots are designed and produced is being funded by a $10 million grant from the National Science Foundation. A team of researchers from the Massachusetts Institute of Technology, Harvard University, and the University of Pennsylvania aims to develop a desktop technology that would make it possible for the average person to design, customize, and print a specialized robot in a matter of hours.
The University of Pennsylvania will lead a $10 million National Science Foundation project to make computer programming faster, easier, and more intuitive. Dubbed ExCAPE for Expeditions in Computer Augmented Program Engineering, the project is a collaborative effort that will involve multiple research institutions, partners in industry, and educational outreach to the next generation of computer scientists.
Computational sprinting is a new approach to smartphone power and cooling that could give users dramatic, brief bursts of computing capability to improve current applications and make new ones possible. Its developers at the University of Pennsylvania and the University of Michigan are pushing mobile chips beyond their sustainable operating limits, much like a sprinter who runs extremely fast for a relatively short distance.