Colloquium 2018
Date | Speaker | Institution | Title |
Jan 19 | Xiaorui Zheng | The City Univ. of New York | Scanning Probe Nano-Lithography with SwissLitho's NanoFrazor |
Jan 26 | Taft Armandroff | McDonald Observatory & UT Austin | Progress and Prospects at the McDonald Observatory |
Feb 2 | Muhammad Bhatti | UTRGV | Cancer Treatment Using High Frequency Electromagnetic Waves |
Feb 9 | Matthew Shetrone | McDonald Observatory & UT Austin | Constraints on Milky Way halo formation using the most metal-rich halo stars |
Feb 16 | Diana Berman | University of North Texas | The Origin of Macroscale Superlubricity in Carbon Nanomaterials |
Feb 23 | Qian Niu | UT Austin | Geometrodynamics of Bloch electrons |
Mar 2 | Choongbae Park | Texas A&M Univ.-Kingsville | Micron-resolution Particle Image Velocimetry (µPIV) Analysis of Microfluidic Applications: Hydrodynamically Confined Flows and Opto-electrokinetic Flows |
Mar 9 | Kevin Stovall | Univ. of New Mexico, National Astronomy Observatory | PALFA Discovery of a Highly Relativistic Double Neutron Star Binary |
Mar 23 | Peter Armitage | Johns Hopkins University | On Ising's model of ferromagnetism |
Apr 20 | Mark Williams | Northeastern University | Single molecule DNA-protein interactions: Battling retroviruses and controlling genome access |
Sep 7 | Myoung-Hwan Kim | UTRGV | Finding Nano-blocks to control light |
Sep 14 | Ahmed Touhami | UTRGV | Biofilms and mechanics: Forces in Microbial Community |
Sep 21 | Weihong Qiu | Oregon State Univ | Kinesin-14s: Moving into a New Paradigm |
Sep 28 | Yuanbing Mao | UTRGV, Chemistry | Correlating the Synthesis-Structure-Property Relationship of Complex Metal Oxide Nanomaterials |
Oct 5 | Hyun-Chul Lee | UTRGV | Understanding of Galaxies Using the Four Corner Stellar Populations in the Color - Magnitude Diagram |
Oct 12 | Baofeng Feng | UTRGV, Math | Mathematical models and computations for ultrashort laser pulse propagation |
Oct 19 | Jun Yan | UMass Amherst | Multi-particle bound states in a two-dimensional semiconductor |
Oct 26 | Luis Grave De Peralta | Texas Tech Univ | Scanning Diffracted-Light (SDL) Imaging |
Nov 9 | Mohammad R. K. Mofrad | UC Berkeley | Physics of Signal Transduction in Living Cells: Conformational Switch, Activation and Clustering |
Nov 16 | Qing Gu | UT Dallas | From Nanoscale Emitters to Photonic Integrated Circuits |
Nov 30 | Marc Normandin | UTRGV | Data analysis methods for gravitational wave searches from binary inspirals and gamma-ray bursts |
Friday, January 19, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Scanning Probe Nano-Lithography with SwissLitho’s NanoFrazor
Progress in nanotechnology depends on the capability to fabricate, position and interconnect nanometer-scale structures. However, existing conventional lithography techniques pose limitations and challenges related to resolution, operational costs, and more importantly, the lack of flexibility to pattern novel materials such as graphene and transition-metal dichalcogenides. Since the first patterning experiments performed with a scanning probe microscope in the late 1980s, scanning probe lithography has emerged as an alternative type of lithography for academic research that provides striking capabilities to pattern three-dimensional relief structures with nanoscale features; the fabrication of the smallest field-effect transistor; or the patterning of proteins with 10-nm feature size. In this presentation, I will introduce the innovative NanoFrazor, the first commercialized scanning probe lithography platform, and focus on its great potential in the emerging research on two-dimensional materials.
Speaker: Dr. Xiaorui Zheng (The City University of New York and SwissLitho)
About the speaker: Dr. Xiaorui Zheng was awarded the degree of PhD at Swinburne University of Technology (Australia) for his thesis entitled “The optics and applications of graphene oxide.” Prior to his appointment as SwissLitho Postdoc Fellow, Xiaorui worked as a research fellow at University of California, San Diego. Xiaorui’s current research interests lie in the nano-photonics of low-dimensional materials for both functional photonic and bio-medical applications using the NanoFrazor.
Friday, January 26, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Progress and Prospects at the McDonald Observatory
Taft Armandroff has served as Director of the McDonald Observatory since June 2014. His talk will include recent progress at McDonald Observatory on new instruments, telescope and instrument upgrades, and plans for the future. A number of enhancements are underway or complete, including a wide-field upgrade and powerful new instrument suite for the Hobby-Eberly 10-meter Telescope. The University of Texas at Austin (UT Austin) is a significant partner in the Giant Magellan Telescope (GMT) in Chile, which will be the world’s largest optical / infrared telescope when it begins commissioning in 2023. GMT plans and prospects and will be reviewed. UT Austin is developing instrumentation for GMT.
Speaker: Dr. Taft Armandroff (McDonald Observatory and UT Austin)
Friday, February 2, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Cancer Treatment Using High Frequency Electromagnetic Waves
The primary objective of this research endeavor is to study and to understand the natural physics phenomenon of electromagnetic resonance in one end closed cavity for the eventual purpose of cancer treatment. Radio Frequency waves are discharged into a coaxial cavity with a small amount (1.532 mL) of breast cancer cells (BT549) and the reflection as well as the power input is measured to determine the absorption power into the vitro cancer cell experiment. When the reflection of the RF waves from the loaded sample of cancer cells is at its lowest power, the RF Frequency is noted and seen to be approximately close to the resonant frequency of that cavity. This cavity can potentially be used as a control method of testing RF frequencies on various types of cancer cells, such as the available BT549 cancer cell line from Biology department. The determined frequency for 1.532 mL of sample article is found to be in the range of radio frequency, but there is much room for improvement depending on the coaxial cavity design such as length and the radii of the coaxial tubes which are under investigation. Some preliminary results are obtained which show that the electromagnetic waves induce cancer cell death via a process known as apoptosis. The results of the experiment will be presented in the colloquium talk.
Speaker: Dr. Muhammad Bhatti (UTRGV)
Friday, February 9, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Constraints on Milky Way halo formation using the most metal-rich halo stars
The Milky Way halo is halo contains mostly very old stars but may still be in the process of construction via cannibalism. While most surveys have concentrated on the most metal-poor stars in the halo we have taken the opposite tactic by looking at the most metal-rich (relatively) stars. Using 6-10 meter class telescopes such as the Magellan, VLT and HET we have constructed a sample of faint, outer halo, metal-rich, in-situ stars for which we have obtained chemical abundance ratios. These abundance ratios reveal their star formation history. Using the SDSS-IV APOGEE survey and combing those results with the early GAIA results we can construct a second set of metal-rich stars in the inner or local halo. We leverage the power of the APOGEE survey by contrasting the abundances of these halo stars against those found in the Milky Way thick disk and bulge. By looking at the results for the metal-rich inner and outer halo stars we speculate on the possible growth mechanisms for the Milky Way halo.
Speaker: Dr. Matthew Shetrone (McDonald Observatory & UT Austin)
About the speaker:
Undergraduate degree: University of Texas at Austin 1991
Graduate degree: University of California, Santa Cruz 1996
Post-doc: ESO fellow (Chile) 1996-1997
Resident Astronomer and Senior Research Scientist for Hobby-Eberly Telescope 1998-2018
Current Service Duties: Science Operations Manager, Deputy Facility Manager
Current Research Duties: APOGEE architect, HET Parallel Scientist
Friday, February 16, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
The Origin of Macroscale Superlubricity in Carbon Nanomaterials.
Tribological systems are an integral part of any moving mechanical assembly, from nanoscale microelectromechanical systems to macroscale automotive and aerospace applications. Minimizing friction and wear-related mechanical failures in order to allow superior performance and long-lasting operation of moving mechanical systems remains the one of today’s greatest challenges. Despite intense research efforts superlubricity, or near zero friction, has seldom been achieved at engineering scales or in practical systems. Much of the difficulty has often been due to the very complex physical, chemical, and mechanical interactions that occur simultaneously at sliding interfaces of mechanical systems. In this study we evaluate tribological performance of carbon nanomaterials [1-2], and demonstrate realization of superlubricity regime at macroscale in an all-carbon-based ensemble when diamond nanoparticles are mixed with graphene and slide against diamond-like carbon (DLC) surface [3]. We show that during sliding in dry atmosphere, graphene patches wrap around tiny diamond nanoparticles and form nanoscrolls, thus dramatically reducing the contact area with a perfectly incommensurate DLC surface. The coefficient of friction reaches ultralow values (0.004) thus demonstrating the long-lasting superlubric regime. This superlubricity is stable over range of temperature, load, and sliding velocity conditions. Our large-scale molecular dynamic simulations elucidate the mesoscopic link between nanoscale mechanics and macroscopic experimental observations. The highlighted carbon-based superlubricity provides a fundamental basis for developing universal friction mechanism and offers a direct pathway for designing smart frictionless tribological systems for practical applications of industrial interest.
References:
[1] D. Berman, et al., special issue in Diamond and Related Materials, 54, 91 (2015).
[2] D. Berman, et al., Materials Today 17 (2014) 31-42.
[3] D. Berman, et al., Science, 348 (2015) 1118-1122
Speaker:
Dr. Diana Berman (University of North Texas)
Dr. Diana Berman is currently an Assistant Professor in the Department of Materials Science and Engineering at University of North Texas. Dr. Berman received her BS in Applied Physics and Math from Moscow Institute of Physics and Technology and PhD in Physics from North Carolina State University. During her PhD she was working on the first generation of RF MEMS switches and the adhesion and wear associated failures in them. Since 2012 she worked as a PostDoctoral researcher and then as a Research Associate in the Center for Nanoscale Materials at Argonne National Laboratory on understanding the fundamental mechanisms of superlubricity, the vanishing friction and wear regime. Dr. Berman’s research interests are in synthesis and characterization of nanostructures, surfaces, and interfaces of ceramic and carbon-based materials for precise control and improvement of their physical properties and performance. Dr. Berman is specifically interested in tribological performance of materials, such as nanoscale contact evolution, interaction of material with environment, and macroscale friction and wear of sliding systems. Dr. Berman has published several high-impact-factor papers with over 1000 citations (in journals Science, Nature Communications, Advanced Functional Materials, ACS Nano, etc) and given several plenary and invited talks and presentations (2017 APS/CNM Annual Meeting, 2016 Gordon Research Conference in Tribology, 2015 Argonne Tribology Workshop). Her work was recognized with TechConnect National Innovation Awards at 2016 and 2017 TechConnect's annual World Innovation Conferences and Expo. Dr. Berman has been an organizer and chair of several Conferences and Workshops (1 st Tribology Workshop and Poster Presentation of STLE North Texas Chapter, STLE Annual Meetings 2016-2017, NDNC 2014, 2015 APS/CNM User Meeting Workshop, 2014 Argonne PostDoctoral Symposium).
Friday, February 23, 2018
Time: 12pm - 1pm
Location: BSABH 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Geometrodynamics of Bloch electrons
Semiclassical dynamics of Bloch electrons in a crystal under slowly varying deformation is developed in the geometric language of a lattice bundle. Berry curvatures and gradients of energy are introduced in terms of lattice covariant derivatives, with the corresponding connections given by the gradient and rate of strain. A number of physical effects are discussed: an effective post-Newtonian gravity at band bottom, polarization induced by spatial gradient of strain, orbital magnetization induced by strain rate, and electron energy stress tensor.
Speaker: Dr. Qian Niu (The University of Texas at Austin)
Friday, March 2, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Micron-resolution Particle Image Velocimetry (μPIV) Analysis of Microfluidic Applications: Hydro-dynamically Confined Flows and Optoelectrokinetic Flows
Two microfluidic applications have been analyzed experimentally using micron-resolution particle image velocimetry (μPIV). The first application is microfluidic probe (MFP) that can be used to generate hydrodynamically confined microflows (HCMs) in open liquid environments. The MFP is immersed in a liquid reservoir and a flow is generated beneath the device. This allows for the application of microfluidic approaches to many biological applications that are typically performed in dishes and well plates. The direct measurement of in-plane velocity fields in the flow beneath an MFP will be presented. Secondly, the combination of AC electric fields and optical illumination allows for the easy and rapid creation of microvortex flows inside a microchannel for applications such as micropumping and micromixing. The manipulation and flow characterization of opto-electrokinetically generated microflows called twin opposing microvortex (TOMV) flows will be presented. This technique has the advantage of simpler construction than competing techniques. The measurement of the microvortex flows generated under non-uniform electric fields and a highly focused laser beam due to a unique characteristics of the TOMV flows will be presented.
Speaker: Dr. Choongbae Park (Texas A&M University - Kingsville)
Friday, March 9, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
PALFA Discovery of a Highly Relativistic Double Neutron Star Binary
In August 2017, the PALFA survey discovered a pulsar (PSR J1946+2052) with a 17 ms spin period in a 1.88 hour, eccentric (e~0.06) orbit with a ~1.2 solar mass companion. Soon after discovery, we used the Jansky Very Large Array to localize PSR J1946+2052 to a precision of 0.09 arcseconds using a new phase binning mode. This improved position allowed for us to measure a spin period derivative which indicates the pulsar has a weak magnetic field compared to "normal" pulsars and therefore has been recycled through mass transfer from a companion. This combined with the orbital eccentricity lead to the conclusion that PSR J1946+2052 is in a DNS system. Among all known radio pulsars in DNS systems, PSR J1946+2052 has the shortest orbital period and the shortest estimated merger timescale, 46 Myr; at that time it will display the largest spin effects on gravitational-wave waveforms of any such system discovered to date. In this talk, I will describe the PALFA survey, the discovery of J1946+2052, and discuss what is currently known about the system. I will also discuss the future plans for this pulsar system including other relativistic orbital parameters that we expect to be able to detect in the coming years.
Speaker: Dr. Kevin Stovall (The Univ. of New Mexico, National Radio Astronomy Observatory, Socorro)
Friday, March 23, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
On Ising's model of ferromagnetism
The 1D Ising model is a classical model of great historical significance for both classical and quantum statistical mechanics. Developments in the understanding of the Ising model have fundamentally impacted our knowledge of thermodynamics, critical phenomena, magnetism, conformal quantum field theories, particle physics, and emergence in many-body systems. Despite the theoretical impact of the Ising model there have been very few good 1D realizations of it in actual real material systems. However, it has been pointed out recently, that the material CoNb2O6, has a number of features that may make it the most ideal realization we have of the Ising model in one dimension. In this talk I will discuss the surprisingly complex physics resulting in this simple model and review the history of "Ising’s model” from both a scientific and human perspective. In the modern context I will review recent experiments by my group and others on CoNb2O6. In particular I will show how low frequency light in the THz range gives unique insight into the tremendous zoo of phenomena arising in this simple material system.
Speaker: Dr. Peter Armitage (Johns Hopkins University)
Friday, April 20, 2018
Time: 12pm - 1pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.106 (Edinburg)
Single molecule DNA-protein interactions: Battling retroviruses and controlling genome access
Optical tweezers allow us to probe the interactions of proteins with single DNA molecules and apply very small forces. Measurement of force-dependent DNA conformations allows us to quantify interactions that govern cellular function. Here we investigate the DNA interactions of human APOBEC3G, an innate antiviral immunity protein that functions as a cytidine deaminase. Our results show that the process of interconversion between monomeric and dimeric states regulates APOBEC3G’s deamination-dependent and deamination-independent inhibition of HIV-1 replication. I will then discuss the role of eukaryotic HMGB proteins in determining nucleosome accessibility, an important mechanism for regulating protein expression. We construct an array of nucleosomes on a single DNA molecule, measuring nucleosome stability in the presence of HMGB proteins. We find significant unwrapping of nucleosomes due to HMBG-DNA binding, the extent of which differs between different types of HMGB proteins. The extent of observed destabilization correlates with the presence of nucleosome-free regions in cells, revealing distinct functions for regulation of nucleosome accessibility by different HMGB proteins.
Speaker: Dr. Mark C. Williams (Northeastern University)
Friday, September 7, 2018
Time: 12pm - 1:30pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Finding Nano-blocks to Control Light
Metasurfaces have emerged in recent years as a platform for designing subwavelength-thick optical components. Such designer optical interfaces introduce spatially-varying optical responses which can mold the wavefronts of light. The reduced dimensionality of optical metasurfaces opens new physics and leads to novel functionalities distinctly different from those in three-dimensional optical materials. In this talk I will introduce the basic concept of metasurfaces to control light propagation in free space and in optical waveguides. Furthermore, I will present our recent experimental demonstration of a new metasurface platform with hyperbolic materials to control light localized on the surface. These metasurfaces can be the main building blocks in mid-/far infrared flat optics and integrated nanophotonics.
Speaker: Dr. Myoung-Hwan Kim (UTRGV)
Friday, September 14, 2018
Time: 12pm - 1:30pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Biofilms and Mechanics: Forces in Microbial Community
Speaker: Dr. Ahmed Touhami (UTRGV)
Friday, September 21, 2018
Time: 12pm - 1:30pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Kinesin-14s: Moving into a New Paradigm
Kinesin-14s are microtubule-based motor proteins that play important roles in cell division. They were originally thought to be minus-end-directed nonprocessive motors that exhibit directional preference toward the microtubule minus ends in multi-motor ensembles but are unable to generate processive (continuous) motility on single microtubules as individual motors. During the past five years, we and others have discovered several “unconventional” kinesin-14 motors that all contain the ability to generate processive motility as individual motors on single microtubules. In this talk, I will present a series of unexpected yet exciting findings from my lab that have markedly expanded current view of the design and operation principles of kinesin-14 motors.
Speaker: Dr. Weihong Qiu (Oregon State University)
Friday, September 28, 2018
Time: 12pm - 1:30pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Correlating the Synthesis-Structure-Property Relationship of Complex Metal Oxide Nanomaterials
Understanding the synthesis-structure-property relationship of functional materials has paramount importance in order to meet the materials needs and challenges of our evolving and expanding society. Complex metal oxides and their nanomaterials have attracted intensive attention due to their chemical composition and structural flexibility, more importantly, their fascinating properties and broad application potentials. In this colloquium, after a brief overview, two types of functional metal oxides will be discussed to exemplify our recent research effort within this context. As an example of advanced (photo)electrochemical materials, it is expected that delafossites with CuIMIIIO2 composition could serve as potential candidates for cost-effective and active electrode material based on cyclic voltammetry and electrochemical impedance spectroscopy measurements along with their onset potential, current density, Tafel slope, charge transfer resistance, and stability. For luminescent materials useful for solid-state lighting, X-ray scintillators, and bioimaging, focus will be placed on our recent studies on the controllable synthesis of A2M2O7 nanoparticles, and investigation of the morphology and composition influence on their photoluminescence and radioluminescence. We have achieved substantial tunability of their particle size, crystal phase, and more importantly, optical properties. In sum, advanced electrochemical and optical materials of complex metal oxides offer bright promise of producing innovative advances across multiple technologies, and thus will continue impacting our lives in substantial ways.
Speaker: Dr. Yuanbing Mao (UTRGV, Chemistry)
Friday, October 5, 2018
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Understanding of Galaxies Using the Four Corner Stellar Populations in the Color – Magnitude Diagram
The Four Corner Stellar Populations in the Color – Magnitude Diagram that I will present in the talk are the blue horizontal-branch stars on the upper left, the tip of the red giant branch stars and the thermally pulsing asymptotic giant branch stars on the upper right, the main-sequence knee feature on the lower right, and the white dwarf cooling sequence on the lower left. The blue horizontal-branch stars, the main-sequence knee feature, and the white dwarf cooling sequence play important roles for the age estimation of star clusters and the tip of the red giant branch stars and the thermally pulsing asymptotic giant branch stars are of importance for the distance measurement of galaxies. I will conclude with the plan for the CSI Galaxies (Center for Stellar populations In Galaxies) at the UTRGV.
Speaker: Dr. Hyun-chul Lee (UTRGV)
Friday, October 12, 2018
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Mathematical models and computations for ultrashort laser pulse propagation
The most recent advances in nonlinear optics include the generation and applications of ultra-short optical pulses, whose time duration is typically of the order of femtoseconds. In this talk, I will present a newly proposed model for describing the propagation of ultra-short pulses in femtosecond regime with a few cycles: the complex short pulse (CSP) equation and its coupled two-component generalization for polarized light in birefringent media. This newly proposed model can be viewed as an analogue, in ultra-short pulse regime, of the nonlinear Schrödinger (NLS) equation and coupled nonlinear Schrödinger (CNLS) equation. From the point view of physics, they are higher order models beyond slowly varying envelop approximation (SVEA). On the other hand, they are completely integrable, more amenable to rigorous analysis and possessing various exact solutions, from the point view of mathematics. Starting from the Maxwell equation, I will firstly derive the complex short pulse and coupled complex short pulse equations. Then I will construct multi-soliton solutions of both bright and dark type, as well as the rogue wave solutions. Secondly, I will propose integrable semi-discrete analogues of these models, where the spatial variable takes values in a lattice, while the integrability of the resulting equations is preserved. We will construct their various exact solutions and apply these semi-discrete model equations as a novel numerical method: integrability-preserved and self-adaptive moving mesh method for the simulations of the original model equations.
Speaker: Dr. Baofeng Feng (UTRGV, Math)
Friday, October 19, 2018
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Multi-particle bound states in a two-dimensional semiconductor
Since the mechanical isolation of graphene – a single atomic layer of carbon atoms arranged in a chicken-wire pattern – in 2004, the studies of atomically-thin two-dimensional (2D) crystals have evolved into a vibrant field with many interesting discoveries and surprises. In the talk, I will discuss our recent investigation of multi-particle bound states in monolayer tungsten diselenide, a 2D semiconductor. The valley and spin degrees of freedom make these bound states highly versatile, and the inherent Coulomb interaction of the high-quality samples we fabricate enables us to observe light emission due to two-, three-, four- and five-particle bound states. We unambiguously determine the spin and valley composition of these states. The luminescence further reveals 2s, 3s and 4s excited Rydberg states in high magnetic fields up to 31 Tesla. These studies pave way for new opportunities to build valleytronic quantum devices, and quantum communication platforms harnessing unique TMDC properties.
Speaker: Dr. Jun Yan (University of Massachusetts Amherst, Physics)
Friday, October 26, 2018
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Scanning Diffracted-Light (SDL) Imaging
Common cameras permit to obtain intensity images of objects; thus, are only sensible to the amplitude of the electric field. However, the phase of the electric field also carries information about the world around us. Intensity images of transparent objects reveal less about the structure of the objects than phase images. For instance, a large variety of living cells are clear; therefore, several phase-recovery imaging techniques have been developed for imaging the phase of light that passes through transparent tissues. The multitude of bright objects visible in the firmament are separated by a transparent and immense medium. The intensity images collected by telescopes give us amazing images of the bright objects filling our Universe. However, intensity images may not tell the complete history because intensity images carry few information about the transparent immensity that separates visible stars, galaxies, and mega structures. I will talk about a novel phase-recovery imaging technique that may allow developing a telescope for obtaining phase- images of the Cosmos. I will also discuss how SDL imaging may also allow developing the first phase-recovery optical nanoscope.
Speaker: Dr. Luis Grave de Peralta (Texas Tech University, Physics)
Friday, November 9, 2018
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Physics of Signal Transduction in Living Cells: Conformational Switch, Activation and Clustering
Living cells sense mechanical signals, and respond actively by changing their phenotype. This process, termed as cellular mechanotransduction, is mediated by a combination of biochemical and biophysical mechanisms via mechanically induced changes in the structure and function of specific molecules and molecular complexes. Our specific attention is on the role of three macromolecular systems in cellular mechanotransduction, namely the integrin-mediated focal adhesions bridging the cell with the extracellular matrix (ECM), and linkers of the nucleoskeleton and cytoskeleton (LINC complexes), and the nuclear pore complex (NPC) at the interface between the cytoplasm and nucleus. Focal adhesions are the immediate sites of cell interaction with the ECM, and as such they play a key role in mechanosensing and mechanotransduction at the edge of the cell. LINC complexes physically link the cytoskeleton and nucleoskeleton to regulate force transmission to the nucleus; their direct associations with focal adhesions through filamentous actin bundles results in ultrafast mechanotransduction. Nuclear pores could also play a role in the overall process of cellular mechanotransduction by exquisitely controlling the material transport in and out of the nucleus, thereby regulating gene expression and protein synthesis. In this seminar, I will present some of our recent efforts aimed at better understanding of these interconnected molecular systems in the context of cellular mechanotransduction.
Speaker: Dr. Mohammad R. K. Mofrad (UC Berkeley, Bioengineering and Mechanical Engineering)
Friday, November 16, 2018
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
From Nanoscale Emitters to Photonic Integrated Circuits
A crucial component in high-performance photonic integrated circuits (ICs) and other chip-scale photonic systems is an on-chip light source that is efficient, economical, silicon (Si)- compatible, and electronically addressable. In this talk, I will cover two types of light sources with the potential to be inserted into photonic ICs: III-V nano-antenna and perovskite microlasers. I will further discuss emerging physics and applications that can be enabled by these material systems, including topological states and unidirectional edge-modes for robust data transport, and metamaterials with hyperbolic dispersion for super-resolution imaging.
Speaker: Dr. Qing Gu (UT Dallas, Electrical and Computer Engineering)
Friday, November 30, 2018
Time: 12 pm - 1:30 pm
Location: BLHSB 1.104 (Brownsville), EACSB 1.104 (Edinburg)
Data analysis methods for gravitational wave searches from binary inspirals and gamma-ray bursts
We investigate and develop data analysis methods for gravitational wave searches from binary inspirals and gamma-ray bursts. The first technique is a low- latency fully coherent network analysis of gravitational wave detector data to infer information on compact binary coalescence. It uses the stationary phase approximation, optimizes using particle swarm optimization, and an implementation is developed for high-performance computing. The second technique concerns gamma-ray bursts. Given a set of observed astrophysical events, such as gamma ray bursts, it is possible to combine gravitational wave detector data that is temporally associated with these events to infer population properties of the sources. A method is presented for better integration of available non-gravitational wave data - mainly from the electromagnetic signature of the events - into such population studies. Given a population model for the gravitational wave emission properties of a class of astrophysical sources, the method combines gravitational and non-gravitational wave data into a joint likelihood function and obtains maximum likelihood estimates of the model parameters. A toy model is used to illustrate the application of the method.
Speaker: Marc Eric Normandin (UTRGV, Physics)