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By working in part at the National Synchrotron Light Source (NSLS),
scientists from Los Alamos National Laboratory have produced a new
glass material by squeezing the metal zirconium under very high
pressures. This glass may be stronger and more resilient than
traditional glasses, and has the potential to be a better material
for medical, sports, and electronics products. The research is
published in the July 15, 2004, issue of Nature.
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Scientists have produced the first molecular-scale
images of DNA binding to an adenovirus enzyme — a step they believe is essential
for the virus to cause infection. The images, which appear on the cover of the
October 2004 issue of Molecular and Cellular Proteomics, show how binding to DNA
may stimulate the enzyme and are already being used to design new antiviral
drugs to block this interaction.
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Using small-angle x-ray diffraction and wide-angle x-ray diffraction, researchers have discovered
the pre-crystalline structures of polymer-blend materials containing both high molecular weight-polymers
that can crystallize and low molecular-weight polymers that cannot crystallize. In one particular blend
with a higher viscosity than the others, the crystallization precursor has a “shish-kebab” structure
the other blends don’t have. This result suggests that viscosity is an important factor that influences
the pre-crystalline structure of high molecular-weight polymers under a shear force.
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We probed titanium (Ti), tantalum (Ta), and scandium (Sc)
environments in the (1-x)Pb(Sc,Ta)O3 – xPbTiO3 relaxor ferroelectric
(PST-PT), which displays variable order–disorder, relaxor, a mixed
phase region, and normal ferroelectric behaviors as x is increased.
The abrupt structural phase transition from rhombohedral to
tetragonal is observed by x-ray diffraction at x = 0.45. According
to x-ray absorption fine structure (XAFS) studies, the structure
around Ta, Sc, or Ti atoms changes differently with x and there are
no abrupt changes at any concentration. No displacements of Ta or Sc
atoms from their oxygen octahedron centers were observed.
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High voltage-activated (HVA) Ca2+ channels in cell membranes
control diverse biological processes, such as muscle contraction and
hormone release. They are composed of α1, α2-δ, β, and sometimes
γ, subunits. The proper expression and function of HVA Ca2+ channels
are critically dependent on the β subunit, which binds directly to
the α interaction domain (AID) in α1, presumably through the β
interaction domain (BID). We have solved the crystal structure of
the conserved core region of β3, alone and in complex with AID, and
of β4 alone.
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We prepared supramolecular assembled fullerenol/poly(dimethylsiloxane)
nanocomposites by solution casting the complexes of fullerenol and
poly(dimethylsiloxane) (PDMS-di-NH2) at different molar ratios. The
results from our small-angle x-ray scattering (SAXS) study of the
nanocomposites indicate that nanodomains of fullerenol aggregates
are confined homogeneously in the PDMS matrix and grow in size when
fullerenol molecules are gradually added.
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