Community College Participants and Projects: 2017
Undergraduate Researcher: Anthony Augustin
Intended Major: Energy Engineering
Home Institution: City College of San Francisco
Research Project: Growth Mechanism of Atom-Thin MoS2 by CVD Method
Faculty Advisor: Prof. Alex Zettl
Postdoctoral Mentor: Dr. Aiming Yan
UC Berkeley Department: Department of Physics
Project Abstract: 2D materials, which are usually between one and a few atomic layers thick, possess many novel properties due to dimensional confinements. Because of their extreme thickness, they could potentially revolutionize many industries, including consumer electronics. However, finding a controllable and scalable synthesis method has been challenging. This research investigated several of the factors influencing the chemical vapor deposition (CVD) synthesis method of atomically thin molybdenum disulfide (MoS2, a 2D transition metal compound with semi-conducting properties).It was found that the granularity of the prepared MoO3 precursor materially impacted the synthesis of MoS2. Additionally, changes to the flow rate during the ‘growth’ and cool-down stages altered the shape of the synthesized MoS2 layers.Poster Presentation
Undergraduate Researcher: Philip Brown
Intended Major: Electrical Engineering and Computer Science
Home Institution: Laney College
Research Project: Measuring the Anomalous Hall Effect in GdCo Nanodots
Faculty Advisor: Prof. Jeff Bokor
Graduate Student Mentor: Amal El-Ghazaly
UC Berkeley Department: Electrical Engineering and Computer Science
Project Abstract: Until very recently, magnetic nanodots used in both magnetic logic and magnetic random access memory have required spin-polarized currents to transfer the angular momentum needed to switch the magnetization, and thereby switch the magnetic logic bit. This particular switching process, however, is limited to nanosecond or greater timescales – much too slow for future electronics. All-Optical Switching accomplishes this phenomenon 1000 times faster: at femtosecond timescales. Since the electronics of the future will be smaller in scale, it is also necessary to characterize the magnetization switching in small-scale devices. The switching is measured using nanodots arranged on anomalous Hall effect crossbars. Various anomalous Hall effect crossbar designs are examined and detection of single nanodot switching of the gadolinium cobalt (GdCo) nanodots is demonstrated. This work helps advance technology by helping to bring about ultrafast and energy efficient memory storage. Poster Presentation
Undergraduate Researcher: Shannon Brown
Intended Major: Environmental Engineering
Home Institution: City College of San Francisco
Research Project: Isolation and Characterization of Plant Growth Promoting Seed Endophytic Bacteria
Research Advisor: Prof. Romy Chakraborty
Postdoctoral Mentor: Dr. Minita Shrestha
UC Berkeley Department: Lawrence Berkeley National Laboratory
Project Abstract: Endophytes are bacteria that actively colonize the internal tissues of host plants and establish lifelong associations without causing any apparent damage or harm. Some endophytes directly promote plant growth through processes like nitrogen fixation, pathogen resistance, and plant hormone production. Additionally, seed endophytes are of special interest as they may be transmitted from generation to generation. Maize (Zea mays), also known as corn, is not only a staple food in many parts of the world, but is also used as a feed crop, to produce ethanol, and is the largest source of agricultural income in the US. Switchgrass (Panicum virgatum L.) is a perennial warm season grass that is used for forage, bioremediation, and bioenergy, increasing its importance to agriculture and soil health [1]. The goal is to isolate, identify, and characterize bacterial endophytes that reside within maize and switchgrass seeds to extend our knowledge of PGP (plant growth promoting) bacterial endophytes. In order to isolate a wide range of endophytes from the seeds, various media were tested and pure isolates were characterized and taxonomically identified using the 16s rRNA gene. Poster Presentation
Undergraduate Researcher: Kimberly Ferry
Intended Major: Bioengineering
Home Institution: Napa Valley College
Research Project: Identification of Glucoside Exporters in Saccharomyces cerevisiae
Faculty Advisor: Prof. John Dueber
Graduate Student Mentors: Tammy Hsu, Parry Grewal
UC Berkeley Department: Department of Bioengineering
Project Abstract: Saccharomyces cerevisiae, commonly known as brewer’s yeast, can be used as a powerful producer of many industrial materials. This project worked towards identifying the transporters in yeast responsible for the export of glucosides. Using glucosides with distinct coloration or fluorescence, ATPase inhibitor and gene knockout procedures can be performed to assess the ability of the export process in the yeast. Gene knockouts can be done by identifying prospective transporters in the cells through literature and using CRISPR to remove the corresponding genes. The cells and supernatants were analyzed using a spectrophotometer for presence of glucosides in and outside the cell. This information can aid in the industrial production of glucosides, and it can help provide information for future research using yeast cells. Poster Presentation
Undergraduate Researcher: Jocelyn Garduno
Intended Major: Mechanical Engineering
Home Institution: Los Angeles Trade-Technical College
Research Project: Understanding Flow and Transport Around a Blood Clot the Oak Ridge Field Research Center
Faculty Advisor: Prof. Shawn Shadden
Postdoctoral Mentor: Dr. Debanjan Mukherjee
UC Berkeley Department: Department of Mechanical Engineerring
Project Abstract: Blood flow plays a key role in the initiation and progression of thrombosis. Being able to understand blood flow, hemodynamic loading, and flow-induced transport around a thrombus enables a better understanding of the disease and its treatment. The goal of this study is to characterize blood flow and transport in the neighborhood of a thrombus having realistic, and arbitrary, geometry and microstructure. We performed computational fluid dynamic simulations using experimentally derived clot geometries and characterized the interaction of unsteady pulsatile flow with the clot. Thereafter, we extracted local transport features as Lagrangian Coherent Structures obtained from computation of Finite Time Lyapunov Exponents for the flow. Finally, we employed tracer particle dynamics to characterize mixing in the thrombus vicinity. Three sets of thrombus geometries – an idealized sphere, and two thrombus models obtained from microfluidic channel experiments – were tested. The results provide valuable insights regarding the transport of proteins, biochemical agents, or thrombolytic drug in the neighborhood of realistic macro-scale blood clots. Poster Presentaion
Undergraduate Researcher: Jonathan Kim
Intended Major: Electrical Engineering and Computer Science
Home Institution: Bakersfield College
Research Project: Synthesis and Characterization of Transition Metal Dichalcogenide and Carbon Nanotube Coaxial Heterostructures
Faculty Advisor: Professor Alex Zettl
Graduate Student Mentor: Scott Meyer
UC Berkeley Department: Department of Chemistry/ Department of Phsyics
Project Abstract: Carbon nanotubes (CNTs) have many fascinating electronic and mechanical properties, such as high electrical conductivity, high tensile strength, and high thermal conductivity. Transition metal dichalcogenides (TMDs) can be grown in a similar tube structure, but exhibit different electronic and mechanical properties. Depending on their elemental composition, these TMD nanotubes can be semiconducting, metallic, or insulating, resulting in tunable properties.1 Coaxial heterostructure composites of a TMD nanotube grown around a CNT would exhibit a unique combination of CNT and TMD properties. Therefore, synthetic approaches of TMD/CNT heterostructure growth via chemical vapor deposition (CVD) are being explored. Raman, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are being used to determine ideal growth conditions for consistent and uniform coaxial heterostructure growth, and to reduce production of non-tubular structures. When these heterostructures can be controllably grown, new transport properties can be explored for potential use in electronics, such as smaller and more efficient battery and solar cells. Poster Presentation
Undergraduate Researcher: Caitlyn Lee
Intended Major: Mechanical Engineering
Home Institution: El Camino College
Research Project: Laser Cutter Fabrication of Repulsive-Force Electrostatic Actuators
Faculty Advisor: Dr. Ronald Fearing
Graduate Student Mentor: Ethan Schaler
UC Berkeley Organization: Biomimetic Millisystems Laboratory
Project Abstract: In recent years, a new class of planar, repulsive-force electrostatic actuators have been designed in the millimeter to centimeter scale. These actuators consist of layers with two conductive electrodes separated by an insulating film. By stacking multiple layers and charging to high voltages (1000-5000 V), these layers produce a repulsive force and separate. Previous fabrication methods use a relatively expensive and time consuming flex-PCB manufacturing process, which entails etching copper-coated plastics into the desired electrode patterns1. This research aims to create the same actuators using the faster, easier, and more cost-effective process for assembling the layers: laser cutting the electrodes from a metallized plastic film or metal sheet and laminating them onto an insulating film substrate. Fabricated actuators successfully generated >4 mN of force at 1000 V, and are then used to power a centimeter-sized mobile robot. Poster Presentation
Undergraduate Researcher: Stephanie Leon
Intended Major: Biomedival Engineering
Home Institution: Woodland Community College
Research Project: Utilization of Substrates in Post Fire Soil by Pyronema omphalodes
Faculty Advisor: Prof. Thomas Bruns
Graduate Student Mentor: Akiko Carver
UC Berkeley Department: Department of Plant and Microbial Biology
Project Abstract: With an increasing frequency and intensity of fires happening around the world, the need to increase knowledge of post-fire soil microbial ecology has become urgent. Fires are detrimental to the soil, leaving it dry, deteriorated, and hydrophobic with diverse substrates that prevent organisms from being able to recolonize it. The soil hydrophobicity can also cause erosion, which is another reason it becomes uninhabitable. However, a group of pyrophilous fungi, including Pyronema omphalodes, has adapted to the post-fire environment. This fungal species’ ability to survive in this soil is important because it can provide nutrients to a new succession of soil-colonizing organisms. There are many substrates present in the soil following a fire, so it is essential to determine which substrates are utilized by P. omphalodes. To do this, cultures of P. omphalodes were grown on minimal media with different carbon sources, including xylose, pectin, peptone, avicel, and carnauba wax, corresponding to substrates that are found in the post-fire environment. Measurements will be made of colony diameter and biomass volume in order to determine growth rates on the various media, with the goal of discovering which substrate it best utilizes. If we can deduce what P. omphalodes grows best on, we can correlate those findings with genomic analysis to infer what enzymes it uses to break down those substrates. Those enzymes are critical as we can use them to remove the pyrolyzed material from the soil and restore the forests after a fire at a faster rate. Poster Presentation
Undergraduate Researcher: Blake McMahon
Intended Major: Biochemistry
Home Institution: Diablo Valley College
Research Project: Investigating the Inhibitory Range of Type II-A Cas9 Inhibitors
Faculty Advisor: Prof. Jennifer A. Doudna
Postdoctoral Mentor: Dr. Kyle Watters
UC Berkeley Organization: Department of Molecular and Cell Biology
Project Abstract: The field of genome engineering was revolutionized by the discovery of CRISPR (clustered regularly interspaced short palindromic repeats) systems, adaptive immune systems found in bacteria and archaea to defend against phage infection. CRISPR systems cleave foreign DNA or RNA using a CRISPR associated (Cas) protein guided by an RNA strand called gRNA, which allows the system to target highly specific sequences. The most commonly used Cas protein, Cas9, is now being used as a genome editing tool in a variety of organisms. Specifically, the Cas9 homolog from the Type II-A CRISPR system in Streptococcus pyogenes is most frequently used. Recently, four anti-CRISPR proteins from bacteriophages were discovered to inhibit the CRISPR system in Listeria monocytogenes[1], two of which were shown to inhibit the Cas9 from S. pyogenes. However, little is known about the diversity of Cas9 proteins that these anti-CRISPRs can inhibit. Therefore, we tested the inhibitory range of the known Type II-A anti-CRISPRs with multiple Cas9 homologs using a cleavage assay. By investigating the ability of these anti-CRISPRs to inhibit a variety of Type II-A Cas9 homologs, this work will set the stage for future efforts to develop broadly inhibiting Cas9 anti-CRISPR proteins. Poster Presentation
Undergraduate Researcher: Slavyana Nedelcheva
Intended Major: Computer Science
Home Institution: College of the Desert
Research Project: Implementing KUKA IIWA Arm Robot into Telemedicine
Faculty Research Advisor: Prof. Ruzena Bajcsy
Postdoctoral Mentor: Dr. David Anton
UC Berkeley Department: Department of Electrical Engineering and Computer Science
Project Abstract: Telemedicine has been established as a means to provide remote medical consultation and training. By using three-dimensional (3D) telepresence technology and robotic systems, it is possible to allow doctors or medical advisors to operate remotely in situations when physical presence is not achievable and time is crucial. The advanced KUKA robot is controlled, which is a model consisting of a seven-joints arm with built-in sensors and smooth edges that provides flexible collaboration with a human operator. A medical advisor, physician, or technician at the remote site can control and interact through this robot. The goal is to attach a 3D camera to the KUKA robot that will retrieve depth images to generate a 3D mesh reconstruction of the patient side and stream it to the remote medical advisor. The proposed solution emphasizes the importance of remote real-time robotic interaction as a solution to improve medical care in rural areas and assistance in emergency situations. Poster Presentation
Undergraduate Researcher: Daisy O’Mahoney
Intended Major: Chemical Engineering
Home Institution: Santa Barbara City College
Research Project:Characterization of Ultrafast Switching Behavior with Scaling of GdCo Nanomagnetic Dots
Faculty Advisor: Prof. Jeffrey Bokor
Graduate Student Mentor: Amal El-Ghazaly
UC Berkeley Department: 2Department of Electrical Engineering and Computer Sciences
Project Abstract: This work aims to bring research closer to faster computing by characterizing the ultrafast femtosecond switching behavior of nanomagnetic GdCo memory bits without the use of spin-polarized currents, by using ultrafast optical laser pulses. While all-optical magnetization reversal was demonstrated in large GdFeCo magnetic dots using only linearly polarized light, it is important to characterize the switching behavior of these dots as they are scaled down dramatically in size. A Ti-Sapphire laser was directed at arrays of GdCo dots varying in diameter from 5µm to 50nm and was used to measure the all-optical switching, hysteresis loops, and time-domain switching behavior of these dots as a function of their size. Poster Presentation
Undergraduate Researcher: Angelica Perlas
Intended Major: Engineering Physics
Home Institution: Ventura College
Research Project: Characterization of Low-Voltage Micro-Electro-Mechanical Relay Integrated Circuits
Faculty Advisor : Prof. Tsu-Jae King Liu
Graduate Student Mentor: Zhixin Alice Ye
UC Berkeley Department: Department of Electrical Engineering and Computer Science
Project Abstract: With the emergence of the Internet of Things, the search for more energy-efficient semiconductor devices has begun. Micro-electro-mechanical (MEM) switches, or relays, have been proposed as alternatives to complementary metal-oxide-semiconductor (CMOS) transistors for ultra-low-power digital logic applications, such as in very-large-scale integrated circuits. This is because the relay mechanism imposes no subthreshold leakage, a switching behavior that CMOS transistors cannot achieve due to the 60 mV/decade minimum subthreshold swing at room temperature. Previous research has successfully demonstrated that a single-relay-based inverter circuit actuates reliably with a sub-100 mV switching voltage1. We aim to demonstrate the reliable low-voltage operation of relay-based integrated circuits. To do this, we characterized different pass-gate logic circuits operating in body bias mode, which enables lower switching voltage. A 2-to-1 multiplexer, or mux, and an OR gate are investigated. The demonstration of MEM switches integrated in low-voltage digital circuits will enable scientists and engineers to design more energy-efficient computer chips. Poster Presentation
Undergraduate Researcher: Sergio Rocha-Fernandez
Intended Major: Chemical Engineering
Home Institution: Cabrillo College
Research Project: Transfer of Ferroelectric Films Using Laser Exfoliation Process
Faculty Advisor: Prof. Sayeef Salahuddin
Postdoctoral Mentor: Dr. Ajay Yadav
UC Berkeley Department: Department off Electrical Engineering and Computer Science
Project Abstract: Improving fabrication methods of transistors has been an area of interest for the integration of ferroelectric materials onto silicon. Incorporating ferroelectric materials into the oxide layer of transistors could potentially open up the path to extremely low-energy electronics. Directly depositing a ferroelectric material like lead zirconate titanate (PZT) onto silicon (Si) poses a challenge due to several factors. In order to circumvent such challenges, we attempt a novel transfer method of laser exfoliation. Standard methods, such as pulsed laser deposition (PLD), were used to deposit PZT on lanthanum strontium manganite (LSMO) on strontium titanate (STO). Using laser light of wavelength 532 nm we can ablate LSMO successfully. Having a transparent layer such as polymethyl methacrylate (PMMA, which can also be used a transfer layer) on top of PZT is then deposited using spin coating method. This whole stack of PMMA/PZT/LSMO/STO was then subjected to laser exposure, which removes LSMO from the substrate STO, leaving behind the PZT on PMMA. This PZT on PMMA can later be transferred onto any substrate such as silicon. By using X-ray diffraction (XRD) we ensure that the materials (PZT, LMSO, and PMMA) have not undergone any undesired changes in any of the processes’ steps. Poster Presentations
Undergraduate Researcher: Pariya Samandi
Intended Major: Electrical Engineering and Computer Science
Home Institution: West Valley College
Research Project: Haptic Feedback for Real-Time Telemedicine Platform
Faculty Advisor : Prof. Ruzena Bajcsy
Postdoctoral Mentor: Dr. David Anton
UC Berkeley Department: Department of Electrical Engineering and Computer Science
Project Abstract: Telemedicine has been developed to provide remote monitoring as well as audio and video conferencing between physicians and patients; however, its deficiency to provide the sense of presence and the lack of human touch calls for more advanced development. With the growing use of novel virtual reality (VR) and augmented reality (AR) technologies, researchers are orienting their efforts to develop new frameworks that improve the sense of presence. These developments will reduce the burden of adversities in efficient communication between medical professionals and patients, eventually providing faster and more cost effective treatments. By creating a telemedicine research prototype that integrates a haptic device with a VR station and an AR station to provide haptic feedback, we enable users to feel remote textures, surfaces, and forces. A framework like this will allow individuals to have advanced and enhanced communication, while experiencing a deeper sense of presence. Poster Presentation
Undergraduate Researcher: Merawhit Temesgen
Intended Major: Software Engineering
Home Institution: Laney College
Research Project: Calculation of Energy Loss in the Left Ventricle from Color Doppler Ultrasound
Faculty Advisor : Prof. Shawn Shadden
Graduate Student Mentor: Sarah Frank
UC Berkeley Department: Department of Mechanical Engineering
Project Abstract: Cardiovascular diseases have been associated with blood flow structures in the heart; however, how these flow structures contribute to the progression of these diseases is poorly understood. Here, color-Doppler ultrasound was employed to assess blood flow in the left ventricle by evaluating kinetic energy losses. Color-Doppler ultrasound is a commonly used clinical tool to measure blood flow, but provides limited data, with velocity information only available in a single dimension. This research seeks to assess whether diagnostic values can be calculated directly from color-Doppler ultrasound data or if it is necessary to reconstruct the flow field by investigating energy losses. Energy losses were calculated in synthetic flow fields and ultrasound data. Preliminary results show there is a predictable relationship between the energy losses found using only the radial velocity and those found using reconstructed velocity fields. Poster Presentation