Human brain organoid models create unprecedented opportunities for study of neurological diseases and early neurologic development. Unfortunately, such a promising system often exhibits impaired growth and suboptimal structure in traditional culture due to the insufficient diffusion of oxygen and nutrients within organoids. To improve solute transport and supply, many engineering tools including hyperoxic incubation and fluidic flow have been routinely incorporated in organoid culture. While these physiological stimuli are known to play an equally important role as their chemical counterparts (e.g., growth factors), their impacts on organoid development are relatively undefined. As a result, effectively engineering the culture microenvironment to optimize organoid differentiation remains challenging. We investigated the individual and combined impacts of flow and hyperoxia, two essential solute transport enhancement tools, by culturing forebrain organoids either in static wells or in our unique culture device in both normoxic and hyperoxic environments. The samples were collected at various time points for various characterizations. Compared to the static normoxia control, we found that organoids cultured in flow and hyperoxia had a significant increase in size and neural architecture, with the maximal benefit imparted by both stimuli together (i.e., flow + hyperoxia). We observed that flow led to an enhanced growth of the cortical plate region due to increased mechanotransduction on the periphery of the organoids. Our results suggest that flow and hyperoxia culture produce structurally improved organoids, suggesting the importance of modulating environmental stimulation in organoid differentiation.

New methods of spacecraft propulsion have been continuously studied since the emergence of astronautics in order to make space travel cheaper and faster, while still collecting data that teaches us more about the universe. Solar sails utilize the momentum of reflected photons to accelerate low mass spacecraft to unprecedented speeds without needing to carry onboard fuel, meaning that they are not limited by the rocket equation as compared to a chemically or electrically propelled vehicle. If successful, a vehicle powered by a solar sail would accelerate near the sun and be able to fly at solar latitudes outside the ecliptic plane and obtain new information about the Sun. To effectively accelerate, it must be ultra lightweight and reflect as much light as possible, it should also be made of a material that withstands extreme temperatures close to the sun while passively cooling the spacecraft and that which it carries. This requires a low density material with a low solar absorptivity and high thermal emissivity. Coating an ultrathin metal such as titanium nitride with an inorganic substrate such as carbon or boron nitride nanotube combines the strength and reflectivity of the metal with the thermal emissivity of the substrate, allowing for a material that could make up a functional solar sail. Here I will overview our work on design and fabrication of such thin films. I will show that ~1 micron thick films can be fabricated by solution process methods and transferred onto various substrates for subsequent post processing.

Common methods of radio frequency (RF) device authentication, such as RFID tags, cost time or energy. An ideal authentication scheme identifies transmitters from data collected in situ. We investigate such a scheme here. Due to hardware imperfections, identically manufactured RF devices transmit slightly different signals. We attempt to extract this discrepancy for use as a fingerprint. A dataset was created consisting of data collected from seven transmitters sending WLAN packets to one receiver. Since wireless channels can distort these transmitter fingerprints, we also introduced the effects of seven different channels on the signals. The received short and long training fields were extracted and used as input to train a neural network to classify the transmitters and evaluate the effect on accuracy of the channels. Further work may be aimed towards eliminating channel distortion.

Evidence spanning decades indicates that weak magnetic fields affect various types of organisms in many different ways. For example, this is seen in animals that display magnetoreception, which is the ability to detect the Earth’s magnetic field navigation during migration season. However, more research is needed to determine how magnetic fields interact with or affect smaller organisms at the cellular level. We seek to determine how weak magnetic fields are altering the physiology of organisms. We also aim to systematize and corroborate or refute the evidence found in previously published experiments. Towards that goal, we are first constructing our own 3-Axes Helmholtz Coils to have greater control over the way the magnetic field interacts with a given cell culture. After building the coils, we will test their efficiency, making sure they perform relatively close to our simulations. Finally, the instrument will be placed inside an incubator. Up to 4 standard 12-well cell culture plates will be hosted within the Helmholtz Coils, and we will observe any changes on them as a function of DC magnetic field strength and exposure times. Preliminary results done with a one-directional Helmholtz coil on Actin, Tubulin, and Mitochondria within smooth muscle cells for 4 hours with a magnetic field of 6 mT show some deformation of mitochondrial and actin structures.

Compliant mechanisms are parts or systems of parts that flex and bend to achieve desired motions. They are often manufactured as a single piece, eliminating sliding and rubbing motions between separate components; this significantly reduces wear and friction. As a result, compliant mechanisms require less maintenance and can be designed to have a longer lifespan than dynamically-equivalent, rigid mechanisms. Additionally, compliant mechanisms are incredibly precise, and can maintain this high precision throughout their entire lifespan. Consequently, in fields where maintenance, lifespan, and precision are top priorities, compliant mechanisms may be superior to rigid, over-constrained alternatives. A caged hinge is a particular type of compliant mechanism that permits rotation about one axis via elastic deformation, while remaining strong in tension along that same axis. Caged hinges have applications in industrial robot arms, wind turbines, satellites, and medical devices. However, there is currently no analytical tool to assist in the design of application-specific caged hinges. In this work, we present a model for predicting maximum stress in caged hinges of different sizes. More specifically, our model maps the relationship between geometry and load to both maximum stress and rotational stiffness. To build this model, we first performed finite element analysis (FEA) in ABAQUS on 65 mechanisms of different geometries, under varying loads. We then used linear-regression gradient-descent optimizations and simple neural networks to construct a multi-step model. Our model predicts maximum stress within a margin of error of 5% compared to FEA results. Future work includes validating stiffness values.

The intersection of magnetism and topological electronic structure in momentum space has gained great interest in the field of condensed matter physics and quantum electronics. There has been great effort in observing magnetic ordering within 2D and quasi-2D materials since their discovery. Novel phenomena such as the anomalous quantum Hall effect, Weyl Fermions and axion insulator phases can be realized in such systems, only that it has proven difficult to engineer well controlled doping concentrations over large areas. MnBi2Te4 and its family MnBi2nTe3n+1 overcome these difficulties as it is easily synthesized into uniform bulk single crystals. Using a laser, photons are directed onto the MnBi2Te4 sample to have its back scattered photons collected and sorted by wavelength within a spectrometer. A charge couple device then detects the number of photons, or intensity, per wavelength to provide a unique signature of the molecule. The Raman signatures of MnBi2Te4 demonstrate the E modes at 27 cm-1, 67 cm-1, & 104 cm-1 and A modes at 47 cm-1, 124 cm-1 and 140 cm-1 with the newly observed E mode peak measured at 27cm-1. A 1D scan of the MnBi2Te4 is performed on silicon substrate using a motorized stage to provide a gradient of each material’s intensity across the sample’s surface. With this enhancement of the Raman spectrum to MBT-124, the pronouncement of the vibrational modes will provide a new scope in observing its magnetic ordering when subjected to a range of cryogenic temperature and magnetic field variances.