Every great structure, from the Empire State Building to the Golden Gate Bridge, depends on specific mechanical properties to remain strong and reliable. Rigidity—a material's stiffness—is of particular importance for maintaining the robust functionality of everything from colossal edifices to the tiniest of nanoscale structures. In biological nanostructures, like DNA networks, it has been difficult to measure this stiffness, which is essential to their properties and functions. But scientists at the California Institute of Technology (Caltech) have recently developed techniques for visualizing the behavior of biological nanostructures in both space and time, allowing them to directly measure stiffness and map its variation throughout the network.

The skin is a human being's largest sensory organ, helping to distinguish between a pleasant contact, like a caress, and a negative sensation, like a pinch or a burn. Previous studies have shown that these sensations are carried to the brain by different types of sensory neurons that have nerve endings in the skin. Only a few of those neuron types have been identified, however, and most of those detect painful stimuli. Now biologists at the California Institute of Technology (Caltech) have identified in mice a specific class of skin sensory neurons that reacts to an apparently pleasurable stimulus.

When Matanya Horowitz started his undergraduate work in 2006 at University of Colorado at Boulder, he knew that he wanted to work in robotics—mostly because he was disappointed that technology had not yet made good on his sci-fi–inspired dreams of humanoid robots. "The best thing we had at the time was the Roomba, which is a great product, but compared to science fiction it seemed really diminutive," says Horowitz. He therefore decided to major in not just electrical engineering, but also economics, applied math, and computer science. "I thought that the answer to better robots would lie somewhere in the middle of these different subjects, and that maybe each one held a different key," he explains. Now a doctoral student at Caltech—he earned his masters in the same four years as his multiple undergrad degrees—Horowitz is putting his range of academic experience to work in the labs of engineers Joel Burdick and John Doyle to help advance robotics and intelligent systems

In December 2011, Caltech mineral-physics expert Jennifer Jackson reported that she and a team of researchers had used diamond-anvil cells to compress tiny samples of iron—the main element of the earth's core. By squeezing the samples to reproduce the extreme pressures felt at the core, the team was able to get a closer estimate of the melting point of iron. At the time, the measurements that the researchers made were unprecedented in detail. Now, they have taken that research one step further by adding infrared laser beams to the mix.