REGISTRATION IS REQUIRED
DEADLINE: December 2, 2011
Keynote Speaker: V. Adrian Parsegian (UMass, Amherst)
Keynote Address: In the Age of Order, the Power of Disorder: Flexibility Crowding Transport
Invited Speakers: Moumita Das (SU/RIT), William Dichtel (Cornell), Jay Henderson (SU)
Parking Directions
Location: 701 Clark Hall, Cornell University (click
on directions to find out how to get to Cornell from anywhere in New York; click on maps to locate Clark
Hall.)
Time: 10:00 AM - 5:30 PM followed by informal
discussion and dinner (also to be organized informally)
Organizers: Mark Bowick, Cristina Marchetti, and Jen Schwarz
(Syracuse), Itai
Cohen and Abe Stroock (Cornell) and George Thurston (RIT).
Registration: Please send an email to cew2@cornell.edu to register
by Friday, December 2, 2011. Please include a title
and abstract for your "sound bite" - a three minute update
of your current research. The title and abstract should be in text form
in the body of your e-mail. There will be a $5/person charge to cover
coffee and lunch (to be paid by cash/check on the day of the meeting).
Goal: At this workshop we will have five talks from
researchers in the New York area as well as
one additional keynote speaker. The rest of the time will
be taken up by short (3 min.) presentations. These presentations should
give the audience
a flavor for the research topic and techniques used to
address the research problem discussed. The overall goal is
to give the audience an overview of the type of research
techniques being used and problems being studied in the New
York area. The rest of the time will be unstructured and
available for people to discuss possible collaborations or
other research interests. As such we hope and expect that
students will attend regardless of whether their faculty advisors can
attend.
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Registration: 9:30-10:00 AM
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Welcoming Remarks:
10:00 - 10:05 AM
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Talks: 10:05 - 11:05 AM Jay Henderson (SU), Active Cells Meet Active Materials: Mechanobiological Applications of Shape Memory Polymers in 2D and 3D
Abstract: In vitro studies have begun to elucidate the principles through which extracellular matrix (ECM) behavior supports and regulates tissue development, disease, and healing. Engineered 2D and 3D substrates and scaffolds have provided increasingly powerful tools with which to investigate the relationships between cell mechanical behavior and ECM composition and organization. As engineered in vitro environments become more accurate biochemical and biophysical tools for investigating and modeling in vivo environments, the critical next step for many areas of cell biomechanics and mechanobiology will be incorporation of increased programmable physical functionality into the environments. To this end, we have been investigating the use of shape memory polymers for the study and application of mechanobiology. Here we will present ongoing work on programmable cell culture substrates and scaffolds. The results demonstrate control of cell behavior through shape-memory-activated biophysical changes and introduce the use of such substrates and scaffolds for investigation of mechanotransduction, cell biomechanical function, and cell soft-matter physics. Furthermore, we will discuss the potential for these new approaches to be extended to tissue engineering and regenerative medicine.
Moumita Das (SU/RIT), The Cell Cytoskeleton as a Composite:
Mechanics and Force Transmission
Abstract: The mechanical response of most living cells is largely governed by their cytoskeleton, a composite polymeric scaffold made of a variety of stiff biopolymers and crosslinking proteins. Two major filament systems in the cytoskeleton are actin filaments (F-actin) and microtubules (MTs). Actin filaments are semiflexible, while the much stiffer MTs behave as rigid rods. In this talk I will discuss theories that can explain the synergistic mechanical interplay between F-actin and MTs observed in experiments. First, I will discuss how the direct coupling to the surrounding cytoskeleton allows intracellular MTs to bear large compressive forces ~ 100 pN, and controls the range of force transmission along the MTs which can be as large as tens of microns. Next, I will describe the collective mechanical properties of actin-microtubule composites. We find that stiff filaments such as MTs and stress fibers can not only enhance the stiffness of the cell cytoskeleton, but can also dramatically endow an initially nearly incompressible F-actin matrix with enhanced compressibility relative to its shear compliance with very important consequences for cell mechanics.
A second source of compositeness in the cell cytoskeleton is the presence of different types of crosslinking proteins. For example, some crosslinkers allow the crossing filaments to rotate freely, while others constrain the angle between crosslinked filaments. I shall conclude my talk by briefly discussing a theory that addresses the cooperativity and redundancy in the mechanics of such compositely crosslinked networks.
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Coffee Break: 11:05 - 11:25 AM
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Sound Bites: 11:25 - 12:25 PM
3 minute updates of current research
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Lunch: 12:25 - 1:30 PM (provided)
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Keynote Speaker: 1:30 - 2:30 PM, V. Adrian Parsegian (UMass, Amherst), In the Age of Order, the Power of Disorder: Flexibility Crowding Transport
Abtract: The triumph of modern molecular biology is built on the reasonable assumption that what can be seen in the test tube or cuvette can be seen in the cell. What we know is that this works a remarkable part of the time. What we also know is that we may be looking at features that do not reflect the confinement and crowding that we see in a cell or a virus.
A popular second stage in learning is now to ask, how differently do things work under "crowding" and distorting confinement? What laws and behaviors are preserved, what differ? When does test-tube logic break down?
I will describe the behavior of relatively simple polymers and of DNA under crowded conditions. They deform with energies of crowding that indicate local order and long-range disorder. They push each other for osmotic pressure and for transport - as whole molecules under dilute conditions, as small clusters or strings of "blobs" under crowded conditions. Big molecules push small ones into pores, revealing previously neglected classes of transport, to make us think in new ways about order arising from the entropic stress of disorder.
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Sound Bites: 2:30 PM - 3:30 PM
3 minute updates of current research
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Coffee Break: 3:30 - 3:50 PM
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Talk: 3:50 - 4:20 PM William Dichtel (Cornell), Bottom-up Synthesis of Structurally
Precise Organic Materials
Abstract: The continuing development of organic semiconductors will
bring about efficient solar cells, flexible displays, ubiquitous radio
frequency identification (RFID) tags, improved lighting technologies,
and more sensitive chemical sensors. Organic materials are inexpensive
and offer the promise of tuning device properties through rational
design and chemical synthesis. Simply controlling their chemical
structure is not sufficient, as molecular or polymer films must
achieve long-range overlap of their molecular orbitals to transport
charge efficiently. The organization of complementary organic
semiconductors into covalent organic frameworks (COFs) that have
two-dimensional layered morphologies ideal for photovoltaic
performance will be discussed.
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Informal Discussion: 4:20 - 5:30 PM
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