Previous Editions__________________________________________________________________________SSRL Headlines Vol. 9, No. 9 March, 2009__________________________________________________________________________
Contents of this Issue:
Seasonal influenza kills more than 250,000 people worldwide each year. A
pandemic influenza, such as the highly pathogenic avian influenza (HPAI) H5N1,
poses a grave threat to society. Each seasonal flu vaccine contains three
influenza viruses: one A (H3N2) virus, one A (H1N1) virus, and one B virus. The
viruses in the vaccine change each year based on international surveillance and
scientists' estimations about which types and strains of viruses will circulate
in a given year. However, flu vaccines are not always effective - due in part
to the rapid change of the globular head of hemagglutinin (HA or H), the major
antigen on the surface of flu virus.
Using x-ray crystallography, the team solved the crystal structure of a potent
antibody F10 in complex with hemagglutinin H5. The heavy chain of F10 binds to
a highly conserved pocket, near the fusion peptide, in the stem of
hemagglutinin. Binding of antibody F10 disables HA's ability to induce fusion
between the viral membrane and the host cell membrane, a critical step in
influenza virus infection. The F10 epitope is common among many different types
of flu viruses, which explains its broad spectrum of neutralization against
many different types of flu viruses.
One of the strangest consequences of quantum mechanics is the seemingly
instantaneous communication of subatomic particles over long distances. Known
as quantum entanglement, pairs or groups of particles can become linked so that
any changes made to one will cause the others to respond quicker than the time
it takes for light to travel between them.
Scientists are interested in finding a material that shows quantum entanglement
on a macroscopic scale but which is neither a superconductor nor a superfluid.
Dubbed a topological insulator, this theorized, exotic state of matter would
have unusual conducting properties. For example, changes in the shape of the
surface or edge of this material would not affect its conductance, unlike
typical insulators. Such a material is both interesting as an exotic new state
of matter and could have application to quantum computers since its information
processing properties are insensitive to the presence of impurities, making
quantum operations naturally fault-tolerant.
An international collaboration of scientists led by M. Zahid
Hasan of Princeton
University performed angle-resolved photoemission spectroscopy studies on
SSRL's Beam Line 5-4 to measure the properties of the entangled electrons in a
proposed topological insulator material made from bismuth and antimony.
Combined with data from experiments performed at the COPHEE beam line of the
Swiss Light Source, the study confirmed that the material is fully quantum
entangled. This is the first example of a three-dimensional topological
insulator in nature.
Additionally, this study defined a general method for identifying and
characterizing other topological insulator states of matter. Their results were
published in the February 13 edition of Science.
The Department of Energy's SLAC National Accelerator Laboratory will receive
$68.3 million in funds from President Obama's American Recovery and
Reinvestment Act funds, allowing the laboratory to accelerate the acquisition
of major research equipment and perform seismic upgrades to laboratory
infrastructure. Included is funding for seismic retrofit work on SSRL
buildings. Read full press release at:
http://home.slac.stanford.edu/pressreleases/2009/20090323.htm
see also: Energy Secretary Chu's Announcement regarding $1.2 Billion in
Recovery Act Funding for Science http://www.lightsources.org/cms/?pid=1003391
"The people at SSRL really make it stand out from other facilities," said
Pierre Kennepohl, a University of British Columbia chemist studying sulfur
oxidation at Beam Line 4-3.
That may be because SSRL's staff scientists have an unusual amount of
independence; they spend only half their time helping users launch and maintain
experiments in the beam lines. The other half is dedicated to pursuing their
own research topics, which vary as widely as the specialties of the visiting
users. "The biggest thing is that they understand not just what you're trying
to do, but why you're trying to do it," Kennepohl said. "It really does make a
difference when you're working with people who do their own research." As
accomplished researchers in their own right, SSRL's staff scientists can offer
help beyond instrumentation improvements, that is, provide direct scientific
support and insights.
"It's a pretty strong presence, and a lot of interesting results," said SIMES
Director Zhi-Xun Shen, who attended the meeting. "It's fair to say that,
through the SIMES institute, SLAC now has one of the strongest condensed matter
physics programs in the world."
SLAC scientists also presented new techniques from SSRL and LCLS that will help
condensed-matter physicists glean information about exotic states of matter.
The meeting's talks and poster sessions provided an excellent opportunity to
mix with like-minded researchers from other institutions. "It's important to
get to know the state-of-the-art of the field," said Yves Acremann, a staff
scientist from the joint SLAC-Stanford PULSE Institute for Ultrafast Energy
Science. "We learn what we could do to address problems in solid state physics
with the methods which are unique to SLAC."
Please contact Jackie Kerlegan (jackie@slac.stanford.edu) in the SSRL User
Research Administration group to get a SLAC ID and instructions for logging
into the SLAC Training System. If this is your first time collecting data at
SSRL you must also register as a user at:
see also:
http://www-ssrl.slac.stanford.edu/userresources/check_in_procedures.html
In response to user requests, we have increased the frequency of calls for
proposals and streamlined the process to submit a proposal to conduct X-ray/VUV
experiments at SSRL. Users can now submit new proposals June 1, September 1, or
December 1. In addition, we eliminated the distinction between single
experiment and program proposals, so that we have just one type of standard
proposal valid for two years. All existing proposals are now eligible to
request a one-time extension of two additional years based on the SSRL Proposal
Review Panel's review of the proposal's progress and future plans. We shortened
the proposal body length in the current word document to 3 pages. (We are
developing a web-interface to submit proposals which will launch later this
year). We have reduced the maximum number of external reviewers to six, and we
will more actively seek assistance of SSRL proposal spokespersons in the
external peer review process. For more information on proposal deadlines,
instructions, and forms see
__________________________________________________________________________
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.
__________________________________________________________________________
To leave the SSRL-HEADLINES distribution, send email as shown below:
To: LISTSERV@SSRL.SLAC.STANFORD.EDU
Subject: (blank, or anything you like)
The message body should read
SIGNOFF SSRL-HEADLINES
That's all it takes. (If we have an old email address for you that is
forwarded to your current address, the system may not recognize who
should be unsubscribed. In that case please write to
ssrl-headlines-request@ssrl.slac.stanford.edu and we'll try to figure out
who you are so that you can be unsubscribed.)
If a colleague would like to subscribe to the list, he or she should send
To: LISTSERV@SSRL.SLAC.STANFORD.EDU and use the message body
SUBSCRIBE SSRL-HEADLINES
SSRL Welcome
Page | Science Highlights | Beam Lines |
User Admin | News & Events |
Safety
|
