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Laser-sonic Scanner Aims to Replace Mammograms for Finding Breast Cancer

06-18-18

A laser-sonic scanner, which uses photoacoustic computed tomography (PACT) developed by Lihong Wang, Bren Professor of Medical Engineering and Electrical Engineering, can find tumors in as little as 15 seconds by shining pulses of light into the breast. The laser-sonic scanner provides a safer way for finding breast cancer compared to mammogram technology. Mammograms expose patients to X-ray radiation and requires their breasts to be painfully pressed between plates. Many women avoid having their mammograms taken as often as they should because of the discomfort involved. PACT can provide a clear view of structures as small as a quarter of a millimeter at a depth of 4 centimeters. Mammograms cannot provide soft-tissue contrast with the level of detail in PACT images. The PACT scan is quick, and a clearer image can be developed. [Caltech story]

Tags: research highlights MedE Lihong Wang

Exact Optical Frequencies on Demand

06-11-18

Professor Kerry J. Vahala and colleagues have developed a prototype of a miniature device that synthesizes frequencies on demand with about 1 Hertz accuracy. It combines a frequency comb developed at the National Institute of Standards and Technology (NIST) with a "fine-toothed" frequency comb developed at Caltech. To create the finely spaced comb teeth, the Caltech resonator must be about 100 times larger than the NIST device. Its larger size can potentially make this comb very power hungry. "Too much power in a small space can damage any electronics to which the resonator is connected," Professor Vahala says. "Also, in the future, these synthesizer devices could operate on battery power in smartphone-sized devices where they cannot draw much power." But the Caltech comb can generate specific frequencies with minimal amounts of power. [Caltech story]

Tags: APhMS research highlights Kerry Vahala

Building the Starshot Sail

06-04-18

Professor Harry A. Atwater, Jr. is an advisor to a multi-disciplinary $100-million project aimed at designing a spacecraft that can be launched to planets surrounding other stars and reach them within our lifetime. The Breakthrough Starshot Program has three big technical challenges: The first is to build the so-called photon engine, the laser that's capable of propelling the sail; the second is to design the sail itself; and the third is to design the payload, which will be a tiny spacecraft capable of taking images and spectral data and then beaming them back to the earth. Professor Atwater’s role is to help the program define pathways to making a viable lightsail that's compatible with the other objectives of the whole program. [Caltech story]

Tags: APhMS research highlights Harry Atwater

Quantum and non-linear forces yield peculiar thermal expansion in silicon

05-16-18

Most materials expand when heated. At temperatures below room temperature, silicon shows the opposite behavior, shrinking as it is heated. Even at room temperature the normal thermal expansion of silicon is rather small. A team led by Professor Brent Fultz wanted to know why, and found that the unusual property is the result of quantum effects coupled by the nonlinear forces between atoms in silicon. [Read the paper]

Tags: APhMS research highlights Brent Fultz Dennis Kim

No Motor, No Battery, No Problem

05-15-18

Chiara Daraio, Professor of Mechanical Engineering and Applied Physics, and colleagues have developed robots capable of self-propulsion without using any motors, servos, or power supply. Instead, these first-of-their-kind devices paddle through water as the material they are constructed from deforms with temperature changes. "Combining simple motions together, we were able to embed programming into the material to carry out a sequence of complex behaviors," says Caltech postdoctoral scholar Osama R. Bilal, who is co-first author of the PNAS paper is titled "Harnessing bistability for directional propulsion of soft, untethered robots." [Caltech story]

Tags: research highlights Chiara Daraio MCE APh postdocs Osama Bilal

Solving Pieces of the Genetic Puzzle

05-09-18

Postdoctoral scholar Nathan Belliveau working in the laboratory of Professor Rob Phillips has applied a method called Sort-Seq to mutate small pieces of noncoding regions in E. coli and determined which regions contain binding sites. Binding sites are the locations where specialized proteins that are involved in transcription—the first step in the process of gene expression—attach to DNA. "Humans have such a wide variety of cells—muscle cells, neurons, photoreceptors, blood cells, to name a few," says Professor Phillips. "They all have the same DNA, so how do they each turn out so differently? The answer lies in the fact that genes can be regulated—turned on or off, dialed up and dialed down—differently in different tissues. Until now, there have been no general principles to help us understand how this regulation was encoded." [Caltech story]

Tags: research highlights Rob Phillips APh postdocs Nathan Belliveau

Butterfly Wings Inspire Light-Manipulating Surface for Medical Implants

04-30-18

 

Professor Hyuck Choo along with postdoctoral researchers Radwanul Hasan Siddique, and graduate student Vinayak Narasimhan working in the Choo lab have developed a synthetic analogue for eye implants that makes them more effective and longer-lasting. The work was inspired by tiny nanostructures on transparent butterfly wings. The eye implant is shaped like a tiny drum, the width of a few strands of hair. When inserted into an eye, its surface flexes with increasing eye pressure, narrowing the depth of the cavity inside the drum. That depth can be measured by a handheld reader, giving a direct measurement of how much pressure the implant is under. [Caltech story]

Tags: EE research highlights MedE Hyuck Choo Radwanul Hasan Siddique Vinayak Narasimhan

Graduate Student Wins AAAS Mass Media Fellowship

04-30-18

Giuliana Viglione, a graduate student in Professor Andrew Thompson’s group and a member of the first E111 class has been selected to join the 2018 American Association for the Advancement of Science (AAAS) Mass Media Science & Engineering Fellows Program. The fellows are placed at media organizations nationwide and trained to sharpening their abilities to communicate complex scientific issues to the public. In her research, Giuliana uses robots to investigate small-scale motions in the ocean and what their effect on climate may be.  She will be spending the summer working at King5, an NBC affiliate in Seattle, where she will use her expertise to report on the effects of climate change in the Pacific Northwest.

Tags: honors research highlights ESE Andrew Thompson Giuliana Viglione

Glowing Contact Lens Could Prevent A Leading Cause of Blindness

04-23-18

Hundreds of millions of people suffer from diabetes worldwide, putting them at risk for a creeping blindness, or diabetic retinopathy. Existing treatments, though effective, are painful and invasive, involving lasers and injections into the eyeball. Graduate student, Colin Cook working in Professor Yu-Chong Tai’s laboratory has invented a contact lens that when worn during sleep interrupts the process that destroys cells of the retina. He hopes his contact lenses will offer a solution that patients will be more willing to try because the effort involved is minimal, as are the side effects. [Caltech story]

Tags: research highlights MedE Yu-Chong Tai Colin Cook

Engineered Metasurfaces Replace Adhesive Tape in Specialized Microscope

02-28-18

The latest advance in a new type of optics aimed at improving microscopy started with a game of tennis three years ago between Mooseok Jang a graduate of Professor Changhuei Yang's lab and Yu Horie working with Professor Andrei Faraon. "The hope is that our work will prompt further interest in this area of optics and make this type of microscopy and its advantages feasible for practical, everyday use—not just as a proof of concept," says Josh Brake, a graduate student in Yang's lab who continues to work on the project with Faraon and Yang. [Caltech story]

Tags: EE research highlights Changhuei Yang MedE alumni Andrei Faraon Mooseok Jang APh Yu Horie Josh Brake