Contents of this Issue:
1. Science Highlight —
Faster than the Speed of Melting
(contacts: A.M. Lindenberg, aaronl@slac.stanford.edu and K.J. Gaffney,
kgaffney@slac.stanford.edu)
The process of melting has long been of interest to scientists. In the case of
indium antimonide (InSb), a semiconductor often used to study such processes,
the first steps in melting take a few hundred femtoseconds, a quadrillionth of
a second. But until recently, no one knew what happened after the initial
stages of a phase transition.
Now, in a study led by SLAC researcher Aaron Lindenberg, an international
collaboration of scientists has uncovered new clues about the first instants of
this process. The results are published in the April 4 edition of Physical
Review Letters.
The group used a laser to excite the sample and then measured the structure of
the disordered liquid using short x-ray pulses from the Sub-Picosecond Pulse
Source, a technique called "pump-probe." Lindenberg and colleagues found that
the structure of the disordered liquid was far different from what one would
have expected. Tiny atomic-scale bubbles, called nucleation events, form first
and seed the process, a unique transient state of matter in which large
fluctuations dominate the response of the material.
The group captured the process on a timescale 100 times shorter than any other
previous x-ray study. The results give scientists a deeper understanding of how
disordered materials behave on short timescales, and could lead to improved
materials processing techniques, such as electronics manufacturing.
To learn more about this research see the full scientific highlight at:
Hard X-ray Experiments at the LCLS Pump-Probe Station (XPP), June 20-21,
2008
Rooms may be reserved for these events at the Stanford Guest House for
$75/night at: http://www.stanford.edu/dept/rde/guesthouse/, (650) 926-2800
(group block for the AMO workshop will be released in early May).
—At Other Facilities:
On April 24-25, 2008, the Joint Center for Structural Genomics (JCSG) held its
7th annual meeting in La Jolla, California. Over 80 consortium members, close
collaborators and representatives of the NIH Protein Structure Initiative
program were in attendance, including 13 members of the JCSG Structure
Determination Core, which is based at SSRL. The title for this year's meeting
was "The Expanding Protein Universe". Talks focused on the tremendous
accomplishments of the last year, as JCSG has ramped up its production
activity, resulting in more than 200 novel protein structures being deposited
in the Protein Data Bank. Additional presentations focused on new opportunities
in the area of metagenomics, biomedical targets and interfacing with the
biological research community.
In the interest of fostering a safe and productive sample preparation
laboratory experience for SSRL users, new access policies have been developed
and implemented. Beginning with the next scheduling period (May 1, 2008) users
will continue to request lab access through the SSRL User Research
Administration office, but will receive access codes (which will change with
higher frequency) following review of a revised sample preparation laboratory
use agreement and a brief laboratory training session. The session will
introduce lab users to the organizational scheme within the labs and include
guidelines for the handling of chemicals and wastes. The process will be led
by Cynthia Patty, SSRL's new sample preparation laboratory manager and the
point-of-contact for any question regarding laboratory use at SSRL. We welcome
Cynthia and hope that these changes, coupled with ongoing improvements in the
laboratory equipment and practical organization, will benefit the SSRL user
community.
Proposal Submittal: X-ray/VUV proposals are due May 1. Proposals received by
this date will be peer reviewed and eligible for beam time beginning in
November 2008.
Users are invited to submit rapid access proposals at any time for Bio XAS on
BL7-3, MEIS XAS on BL11-2, Microprobe on BL2-3, and XRD on BL11-3 and
Macromolecular Crystallography on several beam lines. http://www-ssrl.slac.stanford.edu/users/user_admin/deadlines.html
The next deadline for submitting macromolecular crystallography proposals is
July 1. For beam time before fall 2008, please submit a Rapid Access proposal
or contact L. Dunn (lisa@slac.stanford.edu) for more information.
__________________________________________________________________________
SSRL Headlines is published electronically monthly to inform SSRL users,
sponsors and other interested people about happenings at SSRL. SSRL is a
national synchrotron user facility operated by Stanford University for the
U.S. Department of Energy Office of Basic Energy
Sciences. Additional support for
the structural biology program is provided by
the DOE
Office of Biological and Environmental Research, the NIH
National Center for Research Resources and the NIH Institute for General Medical
Sciences. Additional information about
SSRL and its operation and schedules is available from the SSRL WWW
site.
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X-ray diffuse scattering pattern measured on a CCD camera at various times
before and after laser excitation of the semiconductor InSb.
http://www-ssrl.slac.stanford.edu/research/highlights_archive/femtosecond_2008.html
2. Science Highlight —
Taming Asthma-related Proteins Could Lead to Easier
Breathing for Many
(contacts: S.L. LaPorte and K.C. Garcia, Stanford University)
Stanford University School of Medicine scientists working in part at SSRL's
Beam Line 11-1 have uncovered new molecular insights to the mechanism behind
immune disorders such as asthma. Using protein x-ray crystallography at 3.0
Angstrom resolution, researchers Sherry LaPorte and Chris Garcia solved three
structures of two signaling proteins known as "cytokines" in complex with their
shared receptors, where these molecules help regulate immune system activity.
The study was published as the cover story in the January 25 edition of
the journal Cell.
Interleukin-4 and Interleukin-13, cytokines critical to the development of
T cell-mediated humoral immune responses, exert their actions through different
combinations of shared receptors.
Cytokines are a family of proteins and peptides responsible for transmitting
information from cell to cell by binding with special receptors on cell
surfaces. In the current study, Garcia and colleagues worked out three
structures involving two separate cytokines-interleukin-4 (IL-4) and
interleukin-13 (IL-13), which are associated with allergic asthma. Although
both have very different signaling effects, IL-4 and IL-13 are known to bind
with some of the same receptors.
The study revealed that, despite sharing common receptors, very different
chemistries underlie the binding activities of IL-4 and IL-13, a feature that
may play a direct role in immune system disorders such as asthma. The discovery
could lead to future drug therapies that address these differences and help
down-regulate the immune response that results in the life-threatening risks
associated with an asthma attack.
To learn more about this research see the full scientific highlight at:
http://www-ssrl.slac.stanford.edu/research/highlights_archive/IL-4.html
3.
LCLS Proposal Preparation Workshops Announced
AMO and Other Soft X-ray Experiments, June 2-3, 2008
AMO diagnostics chamber
(contacts: H. O'Donnell, heleno@slac.stanford.edu, 650-926-3368 or J.
Bozek, jdbozek@slac.stanford.edu, 650-926-5091)
The Linac Coherent Light Source (LCLS) at SLAC is quickly approaching
completion with first light anticipated in July 2009. The Atomic, Molecular and
Optical (AMO) science end-station will become operational at the same time, and
the first round of proposals to use it are due in September 2008. A workshop
will be held at SLAC on June 2-3, 2008 to assist potential users in
understanding the unique nature of experiments at the LCLS and to prepare a
successful proposal to use the LCLS and the AMO instrumentation. The workshop
will offer participants the opportunity to learn about the LCLS and AMO
instrumentation. Topics to be discussed at the workshop include: Detailed
description of the AMO instrumentation; Expected LCLS FEL beam parameters;
Status of the construction; LCLS access policy; Scientific goals of the AMO
instrumentation; Plans for a soft x-ray beam line for condensed matter
research; Relevant experience from other facilities and techniques;
Presentations of proposed research projects from individual investigators;
Discussions of planned experiments. Given sufficient demand, the workshop may
be repeated in August. Further information will be posted on the web as it
becomes available.
http://www-ssrl.slac.stanford.edu/lcls/AMO
http://www-conf.slac.stanford.edu/amo/2008
(contacts: H. O'Donnell, heleno@slac.stanford.edu, 650-926-3368; D.
Fritz, dmfritz@slac.stanford.edu, 650-926-3779)
The LCLS X-ray Pump Probe (XPP) end-station will become operational in the
summer of 2010, and the first round of proposals to use it will be due in
December 2008. To assist potential users in preparing a successful proposal to
use the XPP instrument, a workshop will be held at SLAC on June 20-21, 2008.
The workshop will provide participants with information needed to write a
successful proposal and offer the opportunity to ask questions about the LCLS
and XPP instrumentation. Topics to be discussed at the workshop include:
Detailed description of the XPP instrumentation; Expected LCLS FEL beam
parameters; Status of the construction; LCLS access policy; Scientific goals of
the XPP instrument; Relevant experience from other facilities and techniques;
Presentations of proposed research projects from the XPP instrument team and
individual investigators; Discussions of planned experiments. Further
information will be posted on the web as it becomes available.
http://www-conf.slac.stanford.edu/xpp
X-ray Pump-Probe Instrument (XPP)
Additional information will be provided at the workshops held in conjunction
with the Joint SSRL and LCLS Users' Meeting on October 15-18, 2008.
4.
Other Upcoming Schools, Users' Meetings and Workshops
—At SLAC:
http://www-conf.slac.stanford.edu/uxss/2008/
http://www.aps.anl.gov/Users/Meeting/2008/
http://www.nsls.bnl.gov/users/meeting/2008/
http://www.lightsource.ca/medsi-sri2008/
5.
JCSG Annual Meeting
(contact: A. Deacon, adeacon@slac.stanford.edu)
6.
New Sample Preparation Laboratory Access Policies at SSRL
(contact: C. Patty, cpatty@slac.stanford.edu)
7.
User Administration Update
(contact: C. Knotts, knotts@slac.stanford.edu)
http://www-ssrl.slac.stanford.edu/users/user_admin/xray_vuv_proposal_guide.html
http://www-ssrl.slac.stanford.edu/users/user_admin/px_proposal_guide.html
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