image of prof. Shan X. Wang
April 2020

Professor Shan X. Wang helped author a paper titled, "A mountable toilet system for personalized health monitoring via the analysis of excreta" that was published in Nature Biomedical Engineering.

The 'smart toilet' is fitted with technology that can detect a range of disease markers in stool and urine, including those of some cancers, such as colorectal or urologic cancers. The device could be particularly appealing to individuals who are genetically predisposed to certain conditions, such as irritable bowel syndrome, prostate cancer or kidney failure, and want to keep on top of their health.

"Our concept dates back well over 15 years," said lead author Sanjiv "Sam" Gambhir, professor and chair of radiology. "When I'd bring it up, people would sort of laugh because it seemed like an interesting idea, but also a bit odd." With a pilot study of 21 participants now completed, Gambhir and his team have made their vision of a precision health-focused smart toilet a reality.

Gambhir's toilet is an ordinary toilet outfitted with gadgets inside the bowl. These tools, a suite of different technologies, use motion sensing to deploy a mixture of tests that assess the health of any deposits. Urine samples undergo physical and molecular analysis; stool assessment is based on physical characteristics.

The toilet automatically sends data extracted from any sample to a secure, cloud-based system for safekeeping. In the future, the system could be integrated into any health care provider's record-keeping system for quick and easy access.


Excerpted from "'Smart toilet' monitors for signs of disease," Stanford Medicine News Center, April 2020



image of professor Krishna Shenoy
April 2020

Researchers from Professor Krishna Shenoy's Group: Saurabh Vyas (Bioengineering PhD candidate), Daniel O'Shea (EE postdoctoral researcher), and Professor Stephen Ryu, M.D. have found that the brain is deeply interested in what happens before you make a movement. Their paper was published in's Neuron.

Existing theories focus on the practice part — the repetition — not the preparation.
In fact, prior to this study, neuroscientists had no reason to think this preparatory state played any part in learning, says Krishna Shenoy. "We're saying that preparation not only has something to do with learning, it might actually be one of the biggest parts of it," adds Krishna who is a Howard Hughes Medical Institute investigator.

To arrive at this new understanding, the researchers explored how monkeys learn a relatively simple motion: how to use a videogame joystick. In a series of experiments, they first trained the monkeys to use the joystick to direct a computer cursor toward a target on the screen. Next, the scientists altered how the joystick worked so that when the monkeys moved the joystick in the direction they thought was upward or leftward or rightward, the cursor moved in a different direction than expected. Thus, the animals had to learn to move the joysticks anew to get the cursor to the target.

Saurabh Vyas uses an analogy to explain the significance of these findings. Imagine LeBron practicing free throws. He shoots the ball, and gets close, and his learning system uses the error to make some changes in the brain. But if his brain activity is disrupted during the planning period — or he doesn't take an instant to pre-visualize the shot — his next attempt will not do as well because he wasn't mindful enough during the critical, pre-movement period.

These findings significantly advance our understanding of the neurological underpinnings of learning. It has long been known that motor and other areas in the brain become active prior to movement. During this preparatory phase, brain activity reflects precise details of how the body should complete a movement.

Consequently, giving the mind more time to prepare — more time to visualize the task at hand — substantially improves learning. From a purely practical standpoint, the findings could reshape how athletes, artists, musicians or anyone who moves their body gets better at what they do.

Ultimately, Krishna and Saurabh hope to apply this new understanding to their specialty: developing prosthetic devices that are controlled by chips implanted in the brain that transform an individual's thoughts into movement. Krishna adds, "The more we understand about how the brain learns new motor skills and performs movement calculations, the more lifelike and realistic we can make thought-controlled prosthetics."


Excerpted from Stanford Engineering,"A team of scientists explore how the brain trains muscles to move" February 26, 2020.



image of Cindy Nguyen, EE PhD candidate and Prof. Tsachy Weissman
March 2020

A collaboration on image compression between researchers and three high school students found human-powered image sharing proved more effective than an algorithm's work. Professor Tsachy Weissman realized the algorithm had hundreds of thousands of human engineering hours, but didn't include human-centric factors that three high schoolers had.


This was the seed for STEM to SHTEM– an internship program for high school students whose various backgrounds, brings tremendous benefit to the research collaboration.


The STEM to SHTEM program kicked off in 2019. 

All of the projects from summer 2019 are included in the "Journal for High Schoolers" which was produced by last year's interns and mentors. Several projects have resulted in papers submitted to scholarly journals, with one planning to be presented at the Human-Robot Interaction Conference in spring. The work also lives on in new collaborations between other research groups who may have remained unacquainted if not for STEM to SHTEM.

Professor Weissman, PhD candidates Cindy Nguyen and Kedar Tatwawadi are currently figuring out what workshops and presentations they and their colleagues can give to the interns this summer. Their goal is to offer sessions that are educational, fun and encouraging.

"During the process of designing what the program would look like, I thought about my experiences as a high school intern and as a first-generation, low-income undergraduate," said Cindy Nguyen (EE PhD candidate). "Being able to give other students the opportunity that I had is such a privilege."

With the program open for applications, the team hopes to draw broad interest from students – including those who lack confidence in their STEM skills, whose talents lie outside STEM or who aren't yet sure about their future academic plans after high school. The program also offers some financial support to students who would otherwise be unable to participate.

"We aim to give every student a taste of the college adventure," said Kedar Tatwawadi (EE PhD candidate). "It could inspire them to take that adventure on and, perhaps, they will even go for graduate studies."

2019 mentors and collaborators included producer and director Devon Baur, sketch artist Frank Hom, and professors Srabanti Chowdhury, Subhasish Mitra, Dorsa Sadigh, Debbie Senesky and Gordon Wetzstein, and the members of their labs.

Note on COVID-19 and STEM to SHTEM program: We plan to proceed with the program for the time being. If needed, we intend to take the program fully online (e.g. weekly lectures via video, mentoring meetings online, etc.) and possibly adapt the start and end date of the program to fit the summer schedules of high schools that are currently dismissed.


image of EE professors Dwight Nishimura and John Pauly
February 2020

Professors Dwight Nishimura, John Pauly, and Albert Macovski lead the Magnetic Resonance Systems Research Lab (MRSRL) in Electrical Engineering. Their lab designs new magnetic resonance imaging (MRI) techniques and equipment for improved disease diagnosis and treatment. These technologies enable MRI scanning with greater speed, clarity, contrast, and comfort. Students and staff work with physicians on imaging solutions for major health problems such as cancer, heart disease, blood vessel disease, and joint pain.

Recently, Dwight and John joined the Medical and Scientific Advisory Board of HeartVista, a pioneer in AI-assisted MRI solutions. The company uses technology that originated in their research lab, MRSRL. Additional details on the MRSRL research can be found on the lab's website: mrsrl.stanford.eduBoth Dwight and John are recipients the highest honor from the International Society for Magnetic Resonance in Medicine – the Gold Medal.

Photo source:


image of professor Shanhui Fan and postdoc researcher Avik Dutt
February 2020


Professor Shanhui Fan and postdoctoral researcher Avik Dutt describe their discovery in an article published in Science.

Essentially, the researchers tricked the photons — which are intrinsically non-magnetic — into behaving like charged electrons. They accomplished this by sending the photons through carefully designed mazes in a way that caused the light particles to behave as if they were being acted upon by what the scientists called a "synthetic" or "artificial" magnetic field.

In the short term, this control mechanism could be used to send more internet data through fiber optic cables. In the future, this discovery could lead to the creation of light-based chips that would deliver far greater computational power than electronic chips. "What we've done is so novel that the possibilities are only just beginning to materialize," said EE postdoc Avik Dutt.

Although still in the experimental stage, these structures represent an advance on the existing mode of computing. Storing information is all about controlling the variable states of particles, and today, scientists do so by switching electrons in a chip on and off to create digital zeroes and ones. A chip that uses magnetism to control the interplay between the photon's color (or energy level) and spin (whether it is traveling in a clockwise or counterclockwise direction) creates more variable states than is possible with simple on-off electrons. Those possibilities will enable scientists to process, store and transmit far more data on photon-based devices than is possible with electronic chips today.

To bring photons into the proximities required to create these magnetic effects, the Stanford researchers used lasers, fiber optic cables and other off-the-shelf scientific equipment. Building these tabletop structures enabled the scientists to deduce the design principles behind the effects they discovered. Eventually they'll have to create nanoscale structures that embody these same principles to build the chip. In the meantime, reports Shanhui Fan, "we've found a relatively simple new mechanism to control light, and that's exciting."

Excerpted from ScienceBlog "What If We Could Teach Photons To Behave Like Electrons?"


Related News

February 2020

The Future of Everything

Professor Jelena Vučković is a Jensen Huang Professor in Global Leadership in the School of Engineering, a Professor of Electrical Engineering and by courtesy of Applied Physics at Stanford, where she leads the Nanoscale and Quantum Photonics Lab. She is a director of Q-FARM (Quantum Science and Engineering Initiative), and is also affiliated with Ginzton Lab, PULSE Institute, SIMES Institute, Stanford Photonics Research Center (SPRC), SystemX Alliance, and Bio-X at Stanford.

Jelena joins podcast host Professor Russ Altman to discuss the power and promise of photonics. Transcript available 


Related News

January 2020

A team led by professor Jelena Vučković explained how they carved a nanoscale channel out of silicon, sealed it in a vacuum and sent electrons through this cavity while pulses of infrared light – to which silicon is as transparent as glass is to visible light – were transmitted by the channel walls to speed the electrons along. Their research is published in the January 3 issue of Science. The accelerator-on-a-chip demonstrated in Science is just a prototype, but Vučković said its design and fabrication techniques can be scaled up to deliver particle beams accelerated enough to perform cutting-edge experiments in chemistry, materials science and biological discovery that don't require the power of a massive accelerator.

"The largest accelerators are like powerful telescopes. There are only a few in the world and scientists must come to places like SLAC to use them," Vučković said. "We want to miniaturize accelerator technology in a way that makes it a more accessible research tool."

Team members liken their approach to the way that computing evolved from the mainframe to the smaller but still useful PC. Accelerator-on-a-chip technology could also lead to new cancer radiation therapies, said physicist Robert Byer, a co-author of the Science paper. Again, it's a matter of size. Today, medical X-ray machines fill a room and deliver a beam of radiation that's tough to focus on tumors, requiring patients to wear lead shields to minimize collateral damage.

"In this paper we begin to show how it might be possible to deliver electron beam radiation directly to a tumor, leaving healthy tissue unaffected," said Byer, who leads the Accelerator on a Chip International Program, or ACHIP, a broader effort of which this current research is a part.

The researchers want to accelerate electrons to 94 percent of the speed of light, or 1 million electron volts (1MeV), to create a particle flow powerful enough for research or medical purposes. This prototype chip provides only a single stage of acceleration, and the electron flow would have to pass through around 1,000 of these stages to achieve 1MeV. But that's not as daunting at it may seem, said Vučković, because this prototype accelerator-on-a-chip is a fully integrated circuit. That means all of the critical functions needed to create acceleration are built right into the chip, and increasing its capabilities should be reasonably straightforward.

The researchers plan to pack a thousand stages of acceleration into roughly an inch of chip space by the end of 2020 to reach their 1MeV target. Although that would be an important milestone, such a device would still pale in power alongside the capabilities of the SLAC research accelerator, which can generate energy levels 30,000 times greater than 1MeV. But Byer believes that, just as transistors eventually replaced vacuum tubes in electronics, light-based devices will one day challenge the capabilities of microwave-driven accelerators.

Meanwhile, in anticipation of developing a 1MeV accelerator on a chip, EE professor Olav Solgaard, a co-author on the paper, has already begun work on a possible cancer-fighting application. Today, highly energized electrons aren't used for radiation therapy because they would burn the skin. Solgaard is working on a way to channel high-energy electrons from a chip-sized accelerator through a catheter-like vacuum tube that could be inserted below the skin, right alongside a tumor, using the particle beam to administer radiation therapy surgically.

"We can derive medical benefits from the miniaturization of accelerator technology in addition to the research applications," Solgaard said.


Excerpted from Stanford News, "Stanford researchers build a particle accelerator that fits on a chip, miniaturizing a technology that can now find new applications in research and medicine". January 2, 2020.


Related News

January 2020

During Fall quarter, professors Abbas El Gamal, Electrical Engineering (EE) and Ram Rajagopal, Civil and Environmental Engineering (CEE), co-organized an interdisciplinary seminar / project course, Battery Systems for Transportation and Grid Services (EE/CEE 292X).

The course provided a holistic view of the subject with particular attention to interactions between different aspects of a battery system. It is intended for those who wish to research, design, analyze, model, apply or just learn about battery systems.


"We connected with our industry speakers to collect relevant projects for the students to work on in the class", shares Thomas Navidi (pictured right), teaching assistant for 292X. "This led to a wide variety of high quality projects ranging from cell thermal design to the economics of grid storage systems. The students worked hard to tackle these problems in a short time and made excellent discoveries.
Many projects have the potential to continue into well developed research papers. We are excited to see how our students can contribute to the research around revolutionary applications of battery technology."

The lectures provided an overview of the design, modeling, analysis, and operation of battery systems for transportation and grid services, and were organized into three parts.

  • Part One: Academic experts (including 5 Stanford faculty) introduced the key building blocks of the battery system.
  • Part Two: Experts from national labs discussed thermal and safety issues in battery systems.
  • Part Three: Industry experts (including from Waymo, Tesla, EVGo, and EPRI) provided an overview of use cases and critical concerns for battery systems being implemented in EVs and the grid, including its economics and lifecycle value. 


"We both are students from industry, and took this class to expand our knowledge in areas that directly relate to our professional roles."

Project Title, "Techno-economic Feasibility of a Hybrid Storage System at Stanford", Jack Pigott, SCPD graduate student and Ushakar Jha, SCPD graduate student 

Students also had to the opportunity to visit Tesla's Gigafactory (pictured at top) in Sparks, NV, for a factory tour and lectures from Tesla engineers on battery cell engineering and production.

TA and PhD candidate Thomas Navidi adds, "The wide variety of knowledgable guest speakers provided a unique opportunity for students to learn a broad range of perspectives about the applications of batteries in transportation and the grid. The industry experts provided insights into the manufacturing and financial aspects that are hard to learn without direct industry experience. The academic speakers provided insight on the state of the art research for batteries performed at academic institutions and the challenges they face."

The course culminated with a student research poster session. There were 22 featured projects spanning a very broad range of topics from battery technology and modeling to applications to transportation and the grid.


"The industry speakers were great; the topics covered and speakers' deep knowledge of their area provided important insights. We appreciated the time for Q and A, and the real-world examples. Working together was also great – we know one another from other classes, and doing this project together was a lot of fun."

Project Title, "Ancillary Services with Vehicle-to-Grid Charging", Michaela Levine, MS candidate, Civil and Environmental Engineering, Velvet Gaston, MS candidate, Civil and Environmental Engineering, and Michelle Solomon, PhD candidate, Materials Science and Engineering



Honors Cooperative Program (HCP), enables qualified working professionals to pursue the MS in Electrical Engineering on a part-time basis. Many classes are offered online, and it is possible to complete the MS degree requirements entirely from a distance. This program is offered in partnership with the Stanford Center for Professional Development (SCPD).

professor Krishna Shenoy
December 2019

Professor Krishna Shenoy and neurosurgeon Jaime Henderson, MD lead a team of researchers that implanted multi-electrode arrays in the brains of study participants who suffered from severe limb weakness. In a recently published study, they found that "two neural population dynamics features previously reported for arm movements were also present during speaking: a component that was mostly invariant across initiating different words, followed by rotatory dynamics during speaking. This suggests that common neural dynamical motifs may underlie movement of arm and speech articulators." Read study

The scientists were able to design software that could differentiate among different syllables uttered by two of the implanted participants who retained the power of speech.

By analyzing neural activity across nearly 200 electrodes, the scientists found they could identify which of several syllables a participant was saying – with more than 80% accuracy in the case of one participant.

The implication here is that someday it may be possible to figure out what people who, for one or another reason, can't speak are trying to say – and get a device to say it for them.

"There aren't a lot of opportunities to make measurements from inside someone's brain while they talk," said postdoctoral research fellow, Sergey Stavisky. If these two people hadn't just happened to have multi-electrode arrays implanted in the part of the brain responsible for hand-movement control, that area's connection to speech might never have surfaced.


image credit: Photos by Peter Barreras/Howard Hughes Medical Institute

Stavisky, Shenoy and Henderson's work could one day help scientists build medical devices that help people who cannot speak. Photo by Peter Barreras/Howard Hughes Medical Institute.


Excerpted from Stanford Medicine's SCOPE Blog, "Why we talk with our hands — and how that may help give speech to the speechless" by Bruce Goldman. 

professor Jelena Vučković
December 2019

Professor Jelena Vučković and team recently published "4H-silicon-carbide-on-insulator for integrated quantum and nonlinear photonics" in Nature Photonics.

Photonic chips could become the basis for light-based quantum computers that could, in theory, break codes and solve certain types of problems beyond the capabilities of any electronic computer.

In recent months Jelena has created a prototype photonic chip made of diamond. Now, however, in experiments described in Nature Photonics, she and her team demonstrate how to make a light-based chip from a material nearly as hard as diamond but far less exotic — silicon carbide.

"These are early stage but promising results with a material that is already familiar to industry," Jelena said.

Commonly used in brake pad linings, silicon carbide is a tough material that has carved out a new niche in electronics, where it is used to make chips for high-voltage, high-heat applications, such as electric car power supplies, that are too extreme for ordinary silicon chips.

Like most chip-making materials, silicon carbide is a crystal — a group of specific atoms arranged in a consistent lattice. In a silicon carbide crystal, every silicon atom is joined to four carbon atoms to form a strong, three-dimensional lattice. The stability of this lattice helps makes silicon carbide useful for high-heat applications, whether that involves dealing with friction in brake pad linings or high currents flowing through chips.

Daniil Lukin (EE PhD candidate), Constantin Dory (EE PhD candidate) and Melissa Guidry (AP PhD candidate) led the effort to make this crystal useful as a photonic chip. They removed silicon atoms at strategic locations throughout the lattice. Each vacancy in the lattice created a subatomic trap that captured a single electron from one of the surrounding carbon atoms. To make the light-based chip work, the researchers sent a stream of photons through the lattice. Whenever a photon struck a trapped electron, the collision between those two particles sent a photon spinning off at a particular energy level, or what scientists call a quantum. Interactions between photons and electrons create what scientists call a qubit, or quantum bit. A qubit is roughly analogous to the transistor in an electronic chip — the fundamental unit that makes the system work.

Many hurdles must still be overcome before photonic chips made of silicon carbide, or diamond for that matter, might become useful as the building blocks for a quantum computing system. "Hype tends to get ahead of science," Vuckovic says. But within the next five years or so, she envisions using photonic chips to send data via quantum light through fiber optic cables, making such communications more secure by making it possible to detect efforts to tap into the flow of information.

As the director of Q-FARM — short for Quantum Fundamentals, Architecture and Machines — Jelena is helping to bring together researchers from Stanford and the SLAC National Accelerator Laboratory to solve the nitty-gritty hardware and software challenges necessary to make quantum technology a reality.

"We're trying to take small, practical steps," she says, "while we try to push beyond the limits of our current understanding and discover new platforms for quantum technologies."

Excerpted from Stanford Engineering's "Can we develop computer chips that run on light?" December 2, 2019. 


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