School of Humanities and Sciences
Showing 241-260 of 377 Results
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Robert Pecora
Professor of Chemistry, Emeritus
Current Research and Scholarly InterestsThe development of the basic principles behind the dynamic light scattering (DLS) technique and its application to a wide variety of liquid systems is one of Pecora's outstanding contributions to physical chemistry. DLS is now an indispensable tool in the repertoire of polymer, colloid and biophysical chemists. It is generally accepted to be one of the best methods for measuring the mutual diffusion coefficients and, in dilute systems, the hydrodynamic sizes of polymers and particulates in solution or suspension. It is widely used, among other things, for studying size distributions of polymer and colloid dispersions; for testing theories of polymer dynamics in dilute and concentrated systems; and for studying interactions between macromolecules and colloidal particles in liquid dispersions. The basic work that established the foundation of this technique was done in the 1960s. Pecora has revisited this area over the years-formulating theories, for instance, of scattering from hollow spheres, large cylindrically symmetric molecules and wormlike chains.
An experimental program began in the early seventies resulted in a now classic series of studies on the rotational dynamics of small molecules in liquids. This work, utilizing mainly depolarized DLS and carbon 13 nuclear magnetic relaxation, has had a wide impact in the area of liquid state dynamics.
It was also during this period that the theoretical foundation for the fluorescence correlation spectroscopy technique (FCS) was formulated. Because of recent advances in equipment and materials, this technique has recently been revived and is now a powerful tool in biophysics.
The experimental and theoretical techniques developed for the study of the dynamics of relatively simple small molecule liquids have been used to investigate more complex systems such as the rotation of small molecule solvents in glassy and amorphous polymers. The resonance- enhanced depolarized light scattering technique was also developed in this period.
Extensive studies using depolarized dynamic light scattering (using the Fabry-Perot interferometer) as well as photon correlation spectroscopy, NMR, FCS and small angle X-ray scattering to the dynamics of oligonucleotides have determined the hydrodynamic diameter of DNA and the internal bending angles of the bases. They also provided support for relations relating hydrodynamic parameters to molecular dimensions for short rodlike molecules and “polyelectrolyte effects” on the translational and rotational motions of these highly charged molecules.
A major area of experimental and theoretical study has been the study of the dynamics of rigid and semirigid rodlike polymers in both dilute and semidilute dispersions. The work on translation and rotation of poly (-benzyl-L-glutamate) in semidilute solution is a foremost early work in this area.
The Pecora group has synthesized and studied the dynamics of model
rigid rod/sphere composite liquids. Studies of the translation of dilute spheres through solutions of the rods as functions of the rod and sphere sizes and the rod concentrations have provided the stimulus for more experiment and theoretical work in this area. Transient electric birefringence decay studies of the rotation of dilute rigid rod polymers in suspensions of comparably sized spherical particles have revealed scaling laws for the rod rotation.
A unique feature of part of this work on rigid and semirigid rodlike polymers is the utilization of genetic engineering techniques to construct a monodisperse, homologous series of DNA restriction fragments. These biologically-produced fragments have served as well-characterized model macromolecules for solution studies of the dynamics of semirigid rodlike polymers.
The well-regarded book of Pecora and Berne on dynamic light scattering, first published in 1976, has become a major reference work. It is now a Dover paperback. -
Vahe Petrosian
Professor of Physics and of Applied Physics
BioHow do things evolve in the universe? How are particles accelerated in the universe?
Professor Petrosian’s research covers many topics in the broad area of theoretical astrophysics and cosmology, with a strong focus on high-energy astrophysical processes.
Cosmological studies deal with global properties of the universe, where the main focus is the understanding of the evolution of the universe at high redshifts, through studies of the evolutions of population of sources such as galaxies and quasars or active galactic nuclei, gamma-ray bursts, using new statistical techniques developed in collaboration with Prof. B. Efron of the Department of Statistics. Another area of research is the use of gravitational lensing in measuring mass in the universe.
High-energy astrophysics research involves interpretation of non-thermal astronomical sources where particles are accelerated to very high energies and emit various kinds of radiation. These processes occur on many scales and in all sorts of objects: in the magnetosphere of planets, in the interplanetary space, during solar and stellar flares, in the accretion disks and jets around stellar-size and super-massive black holes, at centers of galaxies, in gamma-ray bursts, in supernovae, and in the intra-cluster medium of clusters of galaxies. Plasma physics processes common in all these sources for acceleration of particles and their radiative signature is the main focus of the research here. -
Dmitri Petrov
Michelle and Kevin Douglas Professor in the School of Humanities and Sciences
Current Research and Scholarly InterestsEvolution of genomes and population genomics of adaptation and variation
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Eric Pop
Pease-Ye Professor, Professor of Electrical Engineering, Senior Fellow at the Precourt Institute for Energy and Professor, by courtesy, of Materials Science and Engineering and of Applied Physics
Current Research and Scholarly InterestsThe Pop Lab explores problems at the intersection of nanoelectronics and nanoscale energy conversion. These include fundamental limits of current and heat flow, energy-efficient transistors and memory, and energy harvesting via thermoelectrics. The Pop Lab also works with novel nanomaterials like carbon nanotubes, graphene, BN, MoS2, and their device applications, through an approach that is experimental, computational and highly collaborative.
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Manu Prakash
Associate Professor of Bioengineering, Senior Fellow at the Woods Institute for the Environment and Associate Professor, by courtesy, of Oceans and of Biology
BioWe use interdisciplinary approaches including theory and experiments to understand how computation is embodied in biological matter. Examples include cognition in single cell protists and morphological computing in animals with no neurons and origins of complex behavior in multi-cellular systems. Broadly, we invent new tools for studying non-model organisms with significant focus on life in the ocean - addressing fundamental questions such as how do cells sense pressure or gravity? Finally, we are dedicated towards inventing and distributing “frugal science” tools to democratize access to science (previous inventions used worldwide: Foldscope, Abuzz), diagnostics of deadly diseases like malaria and convening global citizen science communities to tackle planetary scale environmental challenges such as mosquito surveillance or plankton surveillance by citizen sailors mapping the ocean in the age of Anthropocene.
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Jonathan Pritchard
Bing Professor of Population Studies, Professor of Genetics and Biology
Current Research and Scholarly InterestsWe are interested in a broad range of problems at the interface of genomics and evolutionary biology. One current focus of the lab is in understanding how genetic variation impacts gene regulation and complex traits. We also have long-term interests in using genetic data to learn about population structure, history and adaptation, especially in humans.
FOR UP-TO-DATE DETAILS ON MY LAB AND RESEARCH, PLEASE SEE: http://pritchardlab.stanford.edu -
Xiaoliang Qi
Professor of Physics
BioMy current research interest is the interplay of quantum entanglement, quantum gravity and quantum chaos. The characterization of quantum information and quantum entanglement has provided novel understanding to space-time geometry, and relate the dynamics of chaotic many-body systems to the dynamics of space-time, i.e. quantum gravity theory. Based on recent progress in holographic duality (also known as AdS/CFT), my goal is to use tools such as tensor networks and solvable models to provide more microscopic understanding to the emergent space-time geometry from quantum states and quantum dynamics.
I am also interested in topological states and topological phenomena in condensed matter systems.
You can find my recent research topics in some talks online:
http://online.kitp.ucsb.edu/online/chord18/opgrowth/
https://www.youtube.com/watch?v=__9VBaLfC6Y&t=42s
http://online.kitp.ucsb.edu/online/qinfo_c17/qi/ -
Stephen Quake
Lee Otterson Professor in the School of Engineering and Professor of Bioengineering, of Applied Physics and, by courtesy, of Physics
Current Research and Scholarly InterestsSingle molecule biophysics, precision force measurement, micro and nano fabrication with soft materials, integrated microfluidics and large scale biological automation.
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Srinivas Raghu
Professor of Physics
BioI am interested in the emergent behavior of quantum condensed matter systems. Some recent research topics include non-Fermi liquids, quantum criticality, statistical mechanics of strongly interacting and disordered quantum systems, physics of the half-filled Landau level, quantum Hall to insulator transitions, superconductor-metal-insulator transitions, and the phenomenology of quantum materials.
Past contributions that I'm particularly proud of include the co-founding of the subject of topological photonics (with Duncan Haldane), scaling theories of non-Fermi liquid metals (with Shamit Kachru and Gonzalo Torroba), Euclidean lattice descriptions of Chern-Simons matter theories and their dualities in 2+1 dimensions (with Jing-Yuan Chen and Jun Ho Son), and 'dual' perspectives of quantum Hall transitions (with Prashant Kumar and Michael Mulligan). -
Alok Ranjan
Physical Science Research Scientist
BioAccomplished Research Scientist with a rich history (6-8 years) of spearheading cutting-edge research projects. Proficient in synthesizing and analyzing new compounds with therapeuIc potenIal. Experienced in uIlizing both structureand property-based strategies to idenIfy promising drug candidates. Led mulIdisciplinary teams to innovate soluIons, enhanced drug discovery efficiency by integraIng advanced computaIonal techniques. CommiYed to conInuous learning and staying well-informed of the latest trends in medicinal chemistry and drug design.
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Jianghong Rao
Professor of Radiology (Molecular Imaging Program at Stanford) and, by courtesy, of Chemistry
Current Research and Scholarly InterestsProbe chemistry and nanotechnology for molecular imaging and diagnostics
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Kristy Red-Horse
Professor of Biology
Current Research and Scholarly InterestsCardiovascular developmental biology
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Seung Yon Rhee
Professor (By Courtesy), Biology
BioSeung Yon (Sue) Rhee is a Senior Staff Member of Plant Biology Department at Carnegie Institution for Science and Professor (by courtesy) in Biology Department, Stanford University. Her group strives to uncover molecular mechanisms underlying adaptive traits in the face of heat, drought, nutrient limitation, and pests. Dr. Rhee’s group studies a variety of plants including models, crops, medicinal and desert plants. Her group employs computational modeling and targeted laboratory testing to study mechanisms of adaptation, functions of novel genes, organization and function of metabolic networks, and chemical and neuronal code of plant-animal interactions. Her group is also interested in developing translational research programs involving biomass maximization under drought in bioenergy crops. More recently, Dr. Rhee has spearheaded a grassroots community building effort called the Plant Cell Atlas initiative, which strives to map all the molecular determinants of plant cells in order to understand and engineer them. Dr. Rhee received her B.A. in biology from Swarthmore College in 1992 and a Ph.D. in biology from Stanford University in 1997. She has been an investigator at Carnegie’s Plant Biology Department since 1999.
