School of Humanities and Sciences
Showing 21-30 of 71 Results
-
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. -
Michael Penn
Teresa Hihn Moore Professor of Religious Studies and Professor, by courtesy, of Classics
BioMichael Penn, the Teresa Hihn Moore Professor of Religious Studies, is a specialist in the history of early Christianity with a particular focus on middle eastern Christians who wrote in the Aramaic dialect of Syriac.
Professor Penn’s first book, Kissing Christians: Ritual and Community in the Late Ancient Church, was published in 2005 by the University of Pennsylvania Press. In 2015 he published two books on Christian-Muslim relations: Envisioning Islam: Syriac Christians in the Early Muslim World (University of Pennsylvania Press) and When Christians First Met Muslims: A Source Book of the Earliest Syriac Writings on Islam (University of California Press). For these projects Professor Penn has received awards from the John Simon Guggenheim Foundation, the American Council for Learned Societies, the National Endowment for the Humanities, the National Humanities Center, the Institute for the Study of the Ancient World, the British Academy, the American Philosophical Association, the American Academy of Religion, and the Wabash Center for Teaching and Learning.
Professor Penn is currently working on an Andrew Mellon Foundation funded collaboration that uses recent advances in the computerized analysis of handwriting to help analyze ancient Aramaic manuscripts. In addition to this work in the digital humanities, Professor Penn has begun several related projects that focus on the history of Syriac Christianity and the manuscripts they produced.
Before joining Stanford, Professor Penn was on the faculty of Mount Holyoke College. He has also taught at Brandeis University, Haverford College, Bryn Mawr College, and Duke University. He has additional experience as a secondary school teacher, including six years as the director of forensics at Durham Academy High School, where he ran a nationally competitive policy debate team. Professor Penn has also held research positions at Apple Computers, the Weizmann Institute (Israel), the Palo Alto Veterans Hospital, and Ames Research Center, NASA.
Ph.D. (Religion) Duke University (1999)
A.B. (Molecular Biology) Princeton University (1993) -
Bissera Pentcheva
Professor of Art and Art History and, by courtesy, of Classics
On Leave from 10/01/2023 To 06/30/2024BioBissera Pentcheva's work focuses on Byzantium and the medieval Mediterranean, more specifically aesthetics, phenomenology, and acoustics. Her most recent book Hagia Sophia: Sound, Space and Spirit in Byzantium (Penn State University Press 2017) explores the interconnection among acoutsics, architecture, and liturgical rite. She has also edited, Aural Architecture in Byzantium: Music, Acoustics and Ritual (Ashgate, 2017). Pentcheva has published another two books with Pennsylvania State University Press: Icons and Power: The Mother of God in Byzantium, 2006 that won the John Nicholas Brown prize form the Medieval Academy of America in 2010 and The Sensual Icon: Space, Ritual, and the Senses in Byzantium, 2010. She has held a number of prestigious fellowships among them: J. S Guggenheim, American Academy of Rome, Wissenschaftskolleg zu Berlin, Mellon New Directions Fellowship for the study of Classical Arabic, Alexander von Humboldt (Germany), Onassis Foundation (Greece), Dumbarton Oaks, and Columbia University's Mellon Post-doctoral fellowship. Her work has been published at the Art Bulletin, Speculum, Gesta, and Res. Anthropology and Aesthetics, and Convivium.
-
Brittany Perham
Lecturer
BioBrittany Perham is the author of DOUBLE PORTRAIT (W.W. Norton, 2017), which received the Barnard Women Poets Prize; THE CURIOSITIES (Free Verse Editions, 2012); and, with Kim Addonizio, the collaborative chapbook THE NIGHT COULD GO IN EITHER DIRECTION (SHP, 2016). She was a Wallace Stegner Fellow from 2009-2011. She lives in San Francisco.
-
C. Ryan Perkins
Curator for South Asian Studies and Islamic Studies, Humanities Resource Group
Current Role at StanfordAs the Curator for South Asian and Islamic Studies I am responsible for building the library's collection of materials from and about South Asia and the Islamic world in English, European languages, and languages of the Middle East, Central Asia, and South Asia. This involves building and sustaining a network of antiquarian dealers, book vendors, scholars, publishers, and libraries in South Asia, Central Asia, and the Middle East. Apart from responding to faculty teaching needs I work in collaboration with the South Asia Center, the Abbasi Program in Islamic Studies, and their affiliates to provide research assistance to faculty, students, and other library users. I also oversee the Bahai collection.
