Stanford University
Showing 101-200 of 331 Results
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Keith Hodgson
David Mulvane Ehrsam and Edward Curtis Franklin Professor of Chemistry and Professor of Photon Science
BioCombining inorganic, biophysical and structural chemistry, Professor Keith Hodgson investigates how structure at molecular and macromolecular levels relates to function. Studies in the Hodgson lab have pioneered the use of synchrotron x-radiation to probe the electronic and structural environment of biomolecules. Recent efforts focus on the applications of x-ray diffraction, scattering and absorption spectroscopy to examine metalloproteins that are important in Earth’s biosphere, such as those that convert nitrogen to ammonia or methane to methanol.
Keith O. Hodgson was born in Virginia in 1947. He studied chemistry at the University of Virginia (B.S. 1969) and University of California, Berkeley (Ph.D. 1972), with a postdoctoral year at the ETH in Zurich. He joined the Stanford Chemistry Department faculty in 1973, starting up a program of fundamental research into the use of x-rays to study chemical and biological structure that made use of the unique capabilities of the Stanford Synchrotron Radiation Lightsource (SSRL). His lab carried out pioneering x-ray absorption and x-ray crystallographic studies of proteins, laying the foundation for a new field now in broad use worldwide. In the early eighties, he began development of one of the world's first synchrotron-based structural molecular biology research and user programs, centered at SSRL. He served as SSRL Director from 1998 to 2005, and SLAC National Accelerator Laboratory (SLAC) Deputy Director (2005-2007) and Associate Laboratory Director for Photon Science (2007-2011).
Today the Hodgson research group investigates how molecular structure at different organizational levels relates to biological and chemical function, using a variety of x-ray absorption, diffraction and scattering techniques. Typical of these molecular structural studies are investigations of metal ions as active sites of biomolecules. His research group develops and utilizes techniques such as x-ray absorption and emission spectroscopy (XAS and XES) to study the electronic and metrical details of a given metal ion in the biomolecule under a variety of natural conditions.
A major area of focus over many years, the active site of the enzyme nitrogenase is responsible for conversion of atmospheric di-nitrogen to ammonia. Using XAS studies at the S, Fe and Mo edge, the Hodgson group has worked to understand the electronic structure as a function of redox in this cluster. They have developed new methods to study long distances in the cluster within and outside the protein. Studies are ongoing to learn how this cluster functions during catalysis and interacts with substrates and inhibitors. Other components of the protein are also under active study.
Additional projects include the study of iron in dioxygen activation and oxidation within the binuclear iron-containing enzyme methane monooxygenase and in cytochrome oxidase. Lab members are also investigating the role of copper in electron transport and in dioxygen activation. Other studies include the electronic structure of iron-sulfur clusters in models and enzymes.
The research group is also focusing on using the next generation of x-ray light sources, the free electron laser. Such a light source, called the LCLS, is also located at SLAC. They are also developing new approaches using x-ray free electron laser radiation to image noncrystalline biomolecules and study chemical reactivity on ultrafast time scales. -
Wray Huestis
Professor of Chemistry, Emerita
BioProfessor Wray Huestis’ research concerns the molecular mechanisms whereby cells control their shape, motility, deformability and the structural integrity of their membranes. Metabolic control of interprotein and protein-lipid interactions is studied by a variety of biochemical, spectroscopic and radiochemical techniques, including fluorescence and EPR spectrometry, autoradiography and electron microscopy. The role of lipid metabolism and transport in regulating the fluid dynamics of cell suspensions (red blood cells, platelets, lymphocytes) is examined using circulating cells and cells grown in culture. Cell-cell and cell-liposome interactions are studied using model membrane systems with widely differing physical properties. Complexes of liposomes and encapsulated viruses are used as selective vectors to deliver water-soluble compounds across the membranes of intact cells. The particular projects described in the listed publications have as a common goal an understanding of the molecular workings of the cell membrane.
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Matthew Kanan
Professor of Chemistry
BioAssociate Professor of Chemistry Matthew Kanan develops new catalysts and chemical reactions for applications in renewable energy conversion and CO2 utilization. His group at Stanford University has recently developed a novel method to create plastic from carbon dioxide and inedible plant material rather than petroleum products, and pioneered the study of “defect-rich” heterogeneous electro-catalysts for converting carbon dioxide and carbon monoxide to liquid fuel.
Matthew Kanan completed undergraduate study in chemistry at Rice University (B.A. 2000 Summa Cum Laude, Phi Beta Kappa). During doctoral research in organic chemistry at Harvard University (Ph.D. 2005), he developed a novel method for using DNA to discover new chemical reactions. He then moved into inorganic chemistry for his postdoctoral studies as a National Institutes of Health Postdoctoral Research Fellow at the Massachusetts Institute of Technology, where he discovered a water oxidation catalyst that operates in neutral water. He joined the Stanford Chemistry Department faculty in 2009 to continue research into energy-related catalysis and reactions. His research and teaching have already been recognized in selection as one of Chemistry & Engineering News’ first annual Talented 12, the Camille Dreyfus Teacher-Scholar Award, Eli Lilly New Faculty Award, and recognition as a Camille and Henry Dreyfus Environmental Mentor, among other honors.
The Kanan Lab addresses fundamental challenges in catalysis and synthesis with an emphasis on enabling new technologies for scalable CO2 utilization. The interdisciplinary effort spans organic synthesis, materials chemistry and electrochemistry.
One of the greatest challenges of the 21st century is to transition to an energy economy with ultra-low greenhouse gas emissions without compromising quality of life for a growing population. The Kanan Lab aims to help enable this transition by developing catalysts and chemical reactions that recycle CO2 into fuels and commodity chemicals using renewable energy sources. To be implemented on a substantial scale, these methods must ultimately be competitive with fossil fuels and petrochemicals. With this requirement in mind, the group focuses on the fundamental chemical challenge of making carbon–carbon (C–C) bonds because multi-carbon compounds have higher energy density, greater value, and more diverse applications that one-carbon compounds. Both electrochemical and chemical methods are being pursued. For electrochemical conversion, the group studies how defects known as grain boundaries can be exploited to improve CO2/CO electro-reduction catalysis. Recent work has unveiled quantitative correlations between grain boundaries and catalytic activity, establishing a new design principle for electrocatalysis, and developed grain boundary-rich copper catalysts with unparalleled activity for converting carbon monoxide to liquid fuel. For chemical CO2 conversion, the group is developing C–H carboxylation and CO2 hydrogenation reactions that are promoted by simple carbonate salts. These reactions provide a way to make C–C bonds between un-activated substrates and CO2 without resorting to energy-intensive and hazardous reagents. Among numerous applications, carbonate-promoted carboxylation enables the synthesis of a monomer used to make polyester plastic from CO2 and a feedstock derived from agricultural waste.
In addition to CO2 chemistry, the Kanan group is pursuing new strategies to control selectivity in molecular catalysis for fine chemical synthesis. Of particular interest in the use of electrostatic interactions to discriminate between competing reaction pathways based on their charge distributions. This effort uses ion pairing or interfaces to control the local electrostatic environment in which a reaction takes place. The group has recently shown that local electric fields can control regioselectivity in isomerization reactions catalyzed by gold complexes. -
Hemamala Karunadasa
J.G. Jackson and C.J. Wood Professor of Chemistry
BioProfessor Hema Karunadasa works with colleagues in materials science, earth science, and applied physics to drive the discovery of new materials with applications in clean energy. Using the tools of synthetic chemistry, her group designs materials that couple the structural tunability of organic molecules with the diverse electronic and optical properties of extended inorganic solids. This research targets materials such as sorbents for capturing environmental pollutants, phosphors for solid-state lighting, and absorbers for solar cells.
Hemamala Karunadasa studied chemistry and materials science at Princeton University (A.B. with high honors 2003; Certificate in Materials Science and Engineering 2003), where her undergraduate thesis project with Professor Robert J. Cava examined geometric magnetic frustration in metal oxides. She moved from solid-state chemistry to solution-state chemistry for her doctoral studies in inorganic chemistry at the University of California, Berkeley (Ph.D. 2009) with Professor Jeffrey R. Long. Her thesis focused on heavy atom building units for magnetic molecules and molecular catalysts for generating hydrogen from water. She continued to study molecular electrocatalysts for water splitting during postdoctoral research with Berkeley Professors Christopher J. Chang and Jeffrey R. Long at the Lawrence Berkeley National Lab. She further explored molecular catalysts for hydrocarbon oxidation as a postdoc at the California Institute of Technology with Professor Harry B. Gray. She joined the Stanford Chemistry Department faculty in September 2012. Her research explores solution-state routes to new solid-state materials.
Professor Karunadasa’s lab at Stanford takes a molecular approach to extended solids. Lab members gain expertise in solution- and solid-state synthetic techniques and structure determination through powder- and single-crystal x-ray diffraction. Lab tools also include a host of spectroscopic and electrochemical probes, imaging methods, and film deposition techniques. Group members further characterize their materials under extreme environments and in operating devices to tune new materials for diverse applications in renewable energy.
Please visit the lab website for more details and recent news. -
Chaitan Khosla
Wells H. Rauser and Harold M. Petiprin Professor and Professor of Chemistry and, by courtesy, of Biochemistry
Current Research and Scholarly InterestsResearch in this laboratory focuses on problems where deep insights into enzymology and metabolism can be harnessed to improve human health.
For the past two decades, we have studied and engineered enzymatic assembly lines called polyketide synthases that catalyze the biosynthesis of structurally complex and medicinally fascinating antibiotics in bacteria. An example of such an assembly line is found in the erythromycin biosynthetic pathway. Our current focus is on understanding the structure and mechanism of this polyketide synthase. At the same time, we are developing methods to decode the vast and growing number of orphan polyketide assembly lines in the sequence databases.
For more than a decade, we have also investigated the pathogenesis of celiac disease, an autoimmune disorder of the small intestine, with the goal of discovering therapies and related management tools for this widespread but overlooked disease. Ongoing efforts focus on understanding the pivotal role of transglutaminase 2 in triggering the inflammatory response to dietary gluten in the celiac intestine. -
Eric Kool
George A. and Hilda M. Daubert Professor of Chemistry
Current Research and Scholarly Interests• Design of cell-permeable reagents for profiling, modifying, and controlling RNAs
• Developing fluorescent probes of DNA repair pathways, with applications in cancer, aging, and neurodegenerative disease
• Discovery and development of small-molecule modulators of DNA repair enzymes, with focus on cancer and inflammation -
Jason Kronenfeld
Ph.D. Student in Chemistry, admitted Autumn 2021
BioJason Kronenfeld holds a Bachelors of Science in Chemistry with minors in French and Math from The University of Arizona (Graduated May 2021, Summa Cum Laude with Honors). Jason spent his time at UArizona conducting research in Benjamin J. Renquist's group and working with Honors students as a Resident Assistant.
He joined the Renquist research group in 2017 where he has worked on projects related to lactation, metabolic rate, hyperinsulinemia and insulin resistance, asthma, and more. He led work on two projects. 1) Understanding the mechanism by which heat suppresses food intake as an effect of global warming. Increasing heat-stressed food intake is proposed to increase milk production in lactating mammals, increase animal efficiency, and decrease milk production costs. 2) Creating a novel approach to address glycemic control for treatment of type two diabetes mellitus – a collaboration with Dr. Khanna's research group to conduct in silico, in vivo, and in vitro testing of the novel approach.
In Fall 2021, Jason entered the Stanford University PhD program in chemistry, to be eventually followed with a post-doctoral fellowship with the ultimate goal of acting as a principal investigator in academia. He performs research in the DeSimone Lab focused on applications of high-resolution continuous liquid interface production (CLIP) under a National Science Foundation Graduate Research Fellowship. Outside of the lab, Jason is involved in research ethics and public communication initiatives as well as a student-led waltz performance group (Stanford Committee on Research, The Civilian, and the Viennese Ball Opening Committee, respectively). -
Yangjie Li
Postdoctoral Scholar, Chemistry
Current Research and Scholarly Interests1. Fragment correlation mass spectrometry for correlating ion pairs generated from the same fragmentation pathway, achieved by covariance mapping of tandem mass spectra
2. Use mass spectrometry for synthesis and analysis in microdroplets and at solid surfaces, focusing on air/solution, solid/solution, and liquid/liquid interfaces -
Fang Liu
Assistant Professor of Chemistry
Current Research and Scholarly InterestsThe group will develop scalable and controllable processes to produce low dimensional materials and their artificial structures, and unravel their novel static and dynamical properties of broad interest to future photonic, electronic and energy technologies. The topics will include: a) Unraveling time-resolved dynamics in light-induced electronic response of two dimensional (2D) materials artificial structures. b) Fabrication of 1D atomically thin nanoribbon arrays and characterization of the electronic and magnetic properties for the prominent edge states. c) Lightwave manipulation with 2D superlattices. These research projects will provide participating students with broad interdisciplinary training across physics, chemistry, and materials science.
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Lin Liu
Postdoctoral Scholar, Chemistry
BioI finished my undergraduate study in general chemistry at Shandong Normal University in 2014. Later, I continued to my master’s studies in organic chemistry at Lanzhou University. In 2018, I moved to Baylor University conducting research under the mentorship of Professor John L. Wood. During my graduate studies, I mainly focused on the total syntheses of natural products. In 2024, I joined the Khosla lab and Cui lab as a joint postdoc. Outside the lab, I like cooking, playing basketball, and watching movies
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Kang Yong Loh
Ph.D. Student in Chemistry, admitted Autumn 2018
BioI am a PhD graduate student and a Stanford ChEM-H Chemistry/Biology Interface Predoctoral Trainee at Stanford University, Department of Chemistry under the supervision of D.H. Chen Professor of Bioengineering Karl Deisseroth. I am interested in developing new chemical/protein tools to study neuroscience.
I was previously a research assistant at the Institute of Materials Research and Engineering and the Department of Chemistry at the National University of Singapore under the supervision of Provost's Chair Professor of Chemistry Xiaogang Liu. I was an Arnold and Mabel Beckman Fellow at the Beckman Institute of Advanced Science and Technology, University of Illinois at Urbana-Champaign under the supervison of Jay and Ann Schenck Professor of Chemistry Yi Lu on bio-inspired nanomaterials, metalloDNAzymes and sensors. Prior to this, in 2010, I joined the Institute of Bioengineering and Nanotechnology in the laboratories of Professor Ying Jackie Yi-Ru, Professor Zhiqiang Gao and Principal Research Scientist Yanbing Zu to work on ultrasensitive DNA nanoparticle based biosensors. Subsequently in 2014, I worked on upconversion nanomaterials for biological applications under the supervision of Professor Xiaogang Liu at the National University of Singapore and the Institute of Materials Research and Engineering. In Summer 2015, Kang Yong returned to the National University of Singapore, the Institute of Materials Research and Engineering and the Institute of Molecular and Cell Biology under the supervision of Professor Yin Thai Chan to work on semiconductor quantum dots and microfluidics applications.
I obtained my B.S. degree in Chemistry (Highest Distinction and Edmund J. James Scholar Honors) from the University of Illinois at Urbana-Champaign in 2017. -
Gabriela Lomeli
Postdoctoral Scholar, Chemistry
BioGabriela is a Propel Postdoctoral Scholar, co-advised by Professor Carolyn Bertozzi and Professor Polly Fordyce. Gabriela earned her PhD from the UC Berkeley – UC San Francisco Graduate Program in Bioengineering and holds a BS in Chemical Engineering from Stanford University. Her research is broadly centered on the development of microfluidic tools for protein analysis and protein engineering. At present, her main project seeks to engineer proteases to target mucins using a high-throughput microfluidic platform.
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Art Lyubimov
Engineering Science Research Associate (Staff Scientist)
BioI work on developing and supporting new X-ray diffraction data collection, monitoring, and processing software, predominantly for use at synchrotron (SSRL) beamlines but also applicable for X-ray free electron laser experiments.
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Thomas Markland
Associate Professor of Chemistry
Current Research and Scholarly InterestsOur research centers on problems at the interface of quantum and statistical mechanics. Particular themes that occur frequently in our research are hydrogen bonding, the interplay between structure and dynamics, systems with multiple time and length-scales and quantum mechanical effects. The applications of our methods are diverse, ranging from chemistry to biology to geology and materials science. Particular current interests include proton and electron transfer in fuel cells and enzymatic systems, atmospheric isotope separation and the control of catalytic chemical reactivity using electric fields.
Treatment of these problems requires a range of analytic techniques as well as molecular mechanics and ab initio simulations. We are particularly interested in developing and applying methods based on the path integral formulation of quantum mechanics to include quantum fluctuations such as zero-point energy and tunneling in the dynamics of liquids and glasses. This formalism, in which a quantum mechanical particle is mapped onto a classical "ring polymer," provides an accurate and physically insightful way to calculate reaction rates, diffusion coefficients and spectra in systems containing light atoms. Our work has already provided intriguing insights in systems ranging from diffusion controlled reactions in liquids to the quantum liquid-glass transition as well as introducing methods to perform path integral calculations at near classical computational cost, expanding our ability to treat large-scale condensed phase systems. -
Todd Martinez
David Mulvane Ehrsam and Edward Curtis Franklin Professor of Chemistry and Professor of Photon Science
On Leave from 10/01/2024 To 06/30/2025Current Research and Scholarly InterestsAb initio molecular dynamics, photochemistry, molecular design, mechanochemistry, graphical processing unit acceleration of electronic structure and molecular dynamics, automated reaction discovery, ultrafast (femtosecond and attosecond) chemical phenomena
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W. E. Moerner
Harry S. Mosher Professor and Professor, by courtesy, of Applied Physics
Current Research and Scholarly InterestsLaser spectroscopy and microscopy of single molecules to probe biological systems, one biomolecule at a time. Primary thrusts: fluorescence microscopy far beyond the optical diffraction limit (PALM/STORM/STED), methods for 3D optical microscopy in cells, and trapping of single biomolecules in solution for extended study. We explore protein localization patterns in bacteria, structures of amyloid aggregates in cells, signaling proteins in the primary cilium, and dynamics of DNA and RNA.
