2019 Lay Science Talk Abstracts

Keynote: What Poison Frogs Teach Us About Fashion, Chemistry, and Parenting

Dr. Lauren O’Connell, Assistant Professor of Biology, Stanford

Poison frogs have bright coloration that advertises toxicity to potential predators and are active parents, giving tadpoles piggyback rides throughout the rainforest. I will discuss my journey from a community college student to being a professor at Stanford University and my lab’s work on studying poison frogs to unlock the some of the mysteries on how animals evolve new behaviors and physiology.

Feathers of a Bird Stick Together

Laura Matloff, PhD Student, Mechanical Engineering, Stanford

Feathers are the building blocks of a wing, allowing birds to drastically change their wing shapes mid-flight (morphing) to attain maximum flight performance and maneuverability. How do feathers, as separate individual panels, move together to form an aerodynamic wing? And can we understand how feathered bird wings morph to design better flying robots? To gain insight into the underlying mechanisms that coordinate flight feathers, we take a multi-scale approach, measuring feather interactions at different hierarchical levels of organization. We animated the feathers and bones in pigeon cadaver wings through the morphing motion, and measured their three-dimensional kinematic motion using high-resolution motion capture cameras. From the data, we found that feather angles change linearly with an input wrist angle during wing morphing. This means that birds do not control their feathers directly. Instead they move their skeleton and the feathers coordinate themselves naturally due to the elastic tissue connecting them to each other and to the bones. From these biological measurements, we designed feathered robotic wings which we test in a wind tunnel and in free outdoor flight. By understanding the biological concepts within a morphing feathered wing, we can use those principles as building blocks to design and build a successful flying bird robot.

Building Blocks on the Moon! How Microstructure Informs Material Design

Isa Rosa, PhD Student, Civil and Environmental Engineering, Stanford

Imagine you arrive on the Moon today and had to build a structure, what would you build it out of? This is what the project I’m part of investigates: materials to build shielding, roads and landing pads in extraterrestrial environments with limited resources, such as the moon and Mars. The material we focus on combines the abundant soil in these environments with water mined onsite and a biopolymer that can be farmed from microorganisms. After the water evaporates, the material produced has a strength similar to that of residential concrete. The material is called Biopolymer-bound Soil Composite or BSC.

In this talk I will tell the story of how research into the material’s microstructure helped us create a stronger material and changed our design methodology. My work deals with understanding BSC’s mechanical behavior (i.e., how it behaves and breaks under loads) in order to eventually create design tools that engineers can use to create lasting structures in extraterrestrial environments. At the end of my PhD, I hope to have laid building blocks in place so the next students can finish building the framework needed to actually lay BSC building blocks on the Moon.

Innate Immunity: The Building Blocks of Treating and Preventing Cancer

Sabrina Ergun, PhD Student, Biochemistry, Stanford

Every second of every day, potentially cancerous cells are forming within us. Yet, the vast majority of the time we do not get sick. For this we can thank our immune systems, which work tirelessly to protect us from these malignant cells. Our immune system contains two main branches: the innate and the adaptive. The entire immune system can be thought of like a fortress’ defense; always on the lookout for enemies and attacking when they come too close. The innate immune system is the siege walls and the sentries on lookout; the first alert of an incoming attack and the physical barriers that keep the invaders out. The adaptive immune system is the soldiers that respond to the alert and drive away the attackers. Most of the time, the defenses are strong and the castle is safe, but every once in a while, the invaders find a weakness and the cancer takes hold. In a breakthrough discovery, researchers found that we can take advantage of this natural defense mechanism to treat cancer. Essentially, we can aid the defending soldiers by giving them the supplies they need to fight off the invaders. This strategy completely cured the brain tumor of 92 year old former U.S. president Jimmy Carter, among many others. Unfortunately, it does not work for everyone. In many cases, the initial alert from the innate immune system never happens so there are no defending soldiers to aid. The wall has an unknown gap, and the invaders are able to sneak in undetected. To stop this from happening, we need to understand how the wall is built. My research goal is to understand the building blocks of this wall, the innate immune system, to determine how we can strengthen them to someday complete eradicate cancer.

Manifolds and Invariants

Ipsita Datta, PhD Student, Mathematics, Stanford

The world around us, from the surface of the earth to a coffee cup on your desk, is made up of shapes. In my field of research, called geometry and topology, we try to understand the shapes in the natural world by associating with them different structures and numbers, called invariants. One of the earliest ways of constructing such an invariant on surfaces was by breaking up the surface into triangles (in a meaningful and consistent manner) and counting “number of faces – number of edges + number of vertices.” This number can help us distinguish a sphere from a doughnut surface. That is, this number for a sphere will not match the number of a doughnut surface. This shows how powerful the idea of breaking up complicated surfaces into simple triangles can be. In my research I am interested in shapes that are more complicated than a donut. We call these and other more complex shapes manifolds. We try to break up manifolds into simpler objects which we can understand better. Then we try to use the information of how our manifold was built from these simpler ones or how these simpler objects reside in the manifold to develop invariants to understand it. So in some sense we are trying to understand the basic “building blocks” of objects in nature – what they are and how much can they tell us.

Assembling the Methane Cycle for Climate Mitigation

Dr. Gavin McNicol, Postdoc, Earth System Science, Stanford

My field, Earth system science, distills Earth’s complexity into cycles of energy and matter that are simple enough to sketch on the back of an envelope. As Earth scientists, we understand climate change as arising from a human perturbation to one of these cycles, the global carbon cycle. Though the biggest and most talked-about carbon cycle change driving climate warming is the increasing atmospheric concentrations of carbon dioxide, another carbon-based greenhouse gas, methane, is now receiving more attention.

Embedded within the larger carbon cycle, methane also cycles between the different Earth sub-systems, and its increasing concentration in the atmosphere accounts for about one-third of current climate warming. It also has an interesting history. Biological methane production is an ancient microbial metabolism that evolved billions of years ago, before oxygen was a major constituent of the atmosphere, and which persists today within microbial communities living in low-oxygen environments such as flooded wetlands, rice paddies, and cattle stomachs. Methane also has geologic sources, which we’ve tapped over the last two centuries for natural gas energy, and increasingly in recent years as hydraulic fracturing has proliferated across North America.

Today, atmospheric methane concentrations are increasing at a faster rate than ever before, and we can’t fully explain these trends. One big question is exactly how much methane is emitted from wetlands. At Stanford Earth, I’m working to apply AI to big datasets of wetland observations to improve global maps of wetland methane emissions. We hope that by reducing uncertainty in the global methane budget we can help improve climate predictions and policy decisions.

Revisiting the methane cycle also reveals why it’s a good starting point for climate change mitigation. Methane, unlike carbon dioxide, is destroyed in the atmosphere itself, due to photochemical interactions with solar radiation. A methane molecule entering the atmosphere will therefore only stick around for about 8 to 10 years, compared to over 100 years for carbon dioxide. If we can start reducing methane emissions soon, that may translate to a reduction in atmospheric concentrations within decades.

Taking a Big Look at Small Things – Understanding Material Behavior at the Nanoscale

Katherine Sytwu, PhD Student, Applied Physics, Stanford

Nanotechnology is starting to go beyond the research lab and penetrate into our daily lives – it’s why sunscreen blends in with your skin, it’s behind the brightest electronic screens, and it’s what makes the latest batteries charge faster and last longer. Nanoparticles, the small bits of matter that make all this possible, rely on their high surface area relative to their overall volume to improve performance and robustness over traditional, macroscopic materials. However, observing and measuring nanoscale phenomena is difficult with traditional microscopy due to the diffraction limit of light, which limits the length scale we can see. Instead, scientists turn to electron microscopes, which image specimens with electrons instead of light. On top of that, recent developments have transformed one such electron microscope, the transmission electron microscope (TEM), from its traditional role as an imaging tool to a new experimental lab. Nowadays, we can place nanoparticles in various experimental environments (like gas, liquid, heating, cooling, etc.) and study material transformations with near-atomic resolution in real time. These insights then help us better understand how nanoparticle size, shape, and structure can influence material behavior.

Making the Building Blocks of Our Body

Dr. Roberta Sala, Postdoc, Obstetrics & Gynecology/Stem Cell Institute, Stanford

Gametes are the cells that generate new individuals. They represent the initial building blocks of our bodies. Men and women have markedly different gametes, i.e. spermatozoa and oocytes, respectively. The process of fertilization happens when an oocyte and a spermatozoon fuse into a single cell, initiating the cascade of events (defined as embryonic development) that might lead to the birth of a new individual. The original cell divides multiple times to produce millions of additional cells that will form every part of our body. Cells that will eventually produce gametes arise during week 2-3 of embryonic development; therefore, obtaining embryos for analysis to study the early stages of gametes formation poses technical difficulties and ethical concerns. The generation of early stage gametes in the lab could overcome these challenges and is emerging as a frontier in regenerative medicine to help people who suffer from infertility conditions.

It has been shown that the generation of mature gametes is possible in mice, but the stages necessary to achieve this goal in humans still need to be determined. However, it is possible to generate early-stage human gametes, defined as primordial germ cells (PGCs), in the lab. Indeed, in our lab we successfully developed a simplified method to generate PGCs in just a few days. We are now characterizing PGCs that have been generated through this platform. We plan to look at different characteristics of these cells, from the specific regulation of their DNA, to comparing differences between male and female PGCs. Additionally, we aim to analyze their ability to produce functional gametes in vitro. We will first focus on producing functional spermatozoa using a system that allows us to successfully maintain testes biopsies from patients. We plan to produce PGCs and then inject them in these biopsies to track their development into mature sperm once they are in their natural environment.

The platforms that we are developing will possibly make a great impact in the field of regenerative medicine, specifically to treat infertility that occurs either naturally or as a side effect of other health conditions, such as cancer patients undergoing chemotherapy.

From Toilet to Tap: Building My Pipe Dream

Kirin Furst, PhD Student, Environmental Engineering & Science, Stanford

You aren’t going to like this, but hear me out before you freak out. The truth is, drinking water and wastewater aren’t as separate as you might want to think. Everyone pees and everyone poops, right? So if you get your drinking water from a lake or river, and you live downstream from anyone, or if your groundwater lies below someone’s septic field, well… I’ll let you finish that thought. The good news is, water treatment technologies are now so advanced that even straight-up wastewater can be made more pure than even the most attractively bottled spring water – and it’ll still be cheaper in the long run. Forget computer science – this is the Silicon Valley of environmental engineering, where you can already drink purified, delicious wastewater just south of here at the Santa Clara Advanced Water Purification Center! Ok, but I’m not done with the bad news – there are many cities in the US and abroad that can’t (or just won’t) invest in a fancy new drinking water plant. Sure, they can glug some bleach in to kill the bacteria and viruses (and I assure you that’s far better than nothing). But when there are a lot of small organic molecules still dissolved in the water, adding a disinfectant introduces new health concerns… small organic chemicals called disinfection byproducts (aka DBPs)! I am working on some cheap, simple solutions to minimize DBPs in wastewater while still killing all those germs. Let me tell you why I’m excited about sewage, and I’ll share with you how someone who got Cs in high school math and was certifiably “not a STEM person” eventually infiltrated a graduate engineering program at Stanford.

The Science Behind Gender Diversity

Grace Huckins, PhD Student, Neuroscience, Stanford

Popular ideas about sex gender are now changing rapidly, maybe more quickly than they ever have in history. Not only are more people openly and publicly transitioning from female to male, or vice versa, but suddenly innumerable in-between possibilities have opened up. In the span of just a few years, gender has transformed from a binary into a spectrum. As with any cultural change, however, this shift in how we understand gender has attracted critics, many of whom use biology as a defense for their views. We all learn in biology class, they attest, that humans come in two types: XX and XY. Nature has left no room for an in-between.

In my research, I have found that science supports the side of acceptance, diversity, and progress. Based on evidence from neuroscience, psychology, and endocrinology as well as the first-person experiences of trans individuals, I will argue that nature in fact abhors binaries. Not only is gender irreducibly complex and continuous, but it is also in fact impossible to separate a biological concept of “sex” from a cultural concept of “gender,” as is often believed. When we realize that sex and gender are inextricable, as the biological research emphatically demonstrates, we can see that we are not defying nature when we open up the gender spectrum. Rather, we are perhaps living more naturally than we ever have.

Magnetic Levitation of Cells: Looking for Malaria in the Field

Shreya Deshmukh, PhD Student, Bioengineering, Stanford

Malaria is a disease carried by mosquitoes and caused by a parasite that lives in blood cells. It infects 200 million people and kills half a million each year, mostly in developing countries (largely in Africa), where the lack of infrastructure makes it difficult to control and eradicate. One way to target this disease is proper diagnosis and testing, which involves identifying the parasites in a patient’s blood. The current malaria tests have various limitations, especially in field settings where malaria is found. In such places, which often lack electricity and running water, where people cannot afford even the most basic services, and where trained experts are hard to come by, malaria tests must still function, and need to give us better answers today than ever before. To solve this problem, we are working on an exciting new technology: magnetic levitation of cells to detect malaria. We add a tiny drop of blood to our device, which uses small magnets and other low-cost materials to levitate blood cells, and then use a cellphone camera to image the levitation pattern. We can analyse this pattern to identify if the blood is healthy or infected with parasites, all within 15-20 minutes, without needing a power supply, refrigeration, or skilled experts to operate the device. The concept is that different cells will levitate at different heights because of changes in density (which decides whether an object floats or sinks) and in magnetic susceptibility (which decides whether an object is attracted to, or repulsed from, a magnet). By combining biology and physics in this technology, and engineering it for resource-limited settings, our first goal is to develop a test for malaria. Then, we want to adapt this technology to answer other questions, such as counting the parasites, and predicting whether they will respond well to treatment -all things that the current tests struggle with. No one test can currently do all this together, and we hope to assemble those building blocks with our device to provide healthcare workers with a one-stop solution when they are working in the field.

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