UNC PHYSICS AND ASTRONOMY WEEKLY CALENDAR

MONDAY, FEBRUARY 8

4:00 p.m., Room 265, Phillips Hall (UNC-CH)

(Refreshments at 3:30 p.m., Room 277, Phillips Hall)

Physics and Astronomy Colloquium

Edwin Bergin (University. of Michigan)

“The Formation and Survival of Water in the Terrestrial-Planet Forming Zone”

Abstract:  Despite its fundamental importance for life, the origin  of water on
our planet remains a mystery.    Recent astronomical observations
have revealed what may prove to be the ubiquity of water vapor during
the early stages of planet formation.   In this talk we will explore a
simple solution that shows that this water vapor forms in situ and is
capable of protecting itself from molecule-destroying stellar ultraviolet radiation.
We will outline new aspects regarding the dominance of Lyman alpha photons
in the radiation field and how the water chemistry is compensates for
water destruction by these photons.  We will also discuss some of the
implications of this result.   The absorption of this radiation
can control the gas thermodynamics in the upper layers of the protoplanetary
disk.  Similar to the Earth's ozone layer, which shelters the chemistry of life,
the water layer protects other molecules and allows for the presence of a rich
organic chemistry.   More broadly,  the survival of thousands of oceans in the natal
habitable zone potentially allows it to be incorporated into forming planetesimals.

TUESDAY, FEBRUARY 9

No Event Scheduled

WEDNESDAY, FEBRUARY 10

No Event Scheduled

THURSDAY, FEBRUARY 11

3:00 p.m., Room 258, Phillips Hall (UNC-CH)

UNC Condensed Matter Physics Seminar

Professor Robert Riehn (Department of Physics, North Carolina State University)

“A Nanofluidic Toolbox for DNA Analysis”

Abstract:  DNA stretching in nanofluidic channels that are round 100 nm in diameter and 100's of microns long is an emerging technique for the genetic  analysis of long nucleic acid molecules. We will explain why nanofluidic stretching differs from other single-molecule techniques, in particular how the ability to measure individuality is greatly enhanced by the fundamentally different averaging properties. We will present an overview of the basic physics that enables this exciting new technique, and discuss

proof-of-principle experiments that have demonstrated how genetic information can be gathered by the technique.

We will then describe progress in a number of ongoing projects that are based on the basic idea of nanofluidic manipulation of DNA. In particular, we have begun to develop a toolbox for connecting nanochannels into networks, and control the motion of single molecules by creating a spatially and

temporally modulated energy landscape.  In context we also discovered that polyelectrolytes in good solvents can be both stretched and contracted in a.c. electric fields if certain conditions are met.  We further studies the fluctuation spectrum of nanoconfined polymers. The second branch of our current research is the application of nanofluidic confinement to biological problems. In particular we will describe progress in reading the epigenetic code of chromatin, and work towards electric sequencing of DNA.

FRIDAY, FEBRUARY 12

No Event Scheduled