1,205 research outputs found
Process for the preparation of calcium superoxide
Calcium superoxide is prepared in high yields by spreading a quantity of calcium peroxide diperoxyhydrate on the surface of a container, positioning said container in a vacuum chamber on a support structure through which a coolant fluid can be circulated, partially evacuating said vacuum chamber, allowing the temperature of the diperoxyhydrate to reach the range of about 0 to about 40 C; maintaining the temperature selected for a period of time sufficient to complete the disproproriation of the diperoxyhydrate to calcium superoxide, calcium hydroxide, oxygen, and water; constantly and systematically removing the water as it is formed by sweeping the reacting material with a current of dry inert gas and/or by condensation of said water on a cold surface; backfilling the chamber with a dry inert gas; and finally, recovering the calcium superoxide produced
An Overview of the Kauffman Firm Survey: Results From the 2004-2008 Data
Presents findings from longitudinal data on new businesses founded in 2004, including financing structure; products, services, and innovations; and characteristics of the owners. Examines indicators of growth and survival and effects of the recession
An Overview of the Kauffman Firm Survey: Results From the 2004-2007 Data
Based on surveys conducted over four years, provides an overview of trends among U.S. firms established in 2004 and the business and owner characteristics associated with survival and growth, including level of innovation, structure, and financing
Domain Wall Spin Dynamics in Kagome Antiferromagnets
We report magnetization and neutron scattering measurements down to 60 mK on
a new family of Fe based kagome antiferromagnets, in which a strong local spin
anisotropy combined with a low exchange path network connectivity lead to
domain walls intersecting the kagome planes through strings of free spins.
These produce unfamiliar slow spin dynamics in the ordered phase, evolving from
exchange-released spin-flips towards a cooperative behavior on decreasing the
temperature, probably due to the onset of long-range dipolar interaction. A
domain structure of independent magnetic grains is obtained that could be
generic to other frustrated magnets.Comment: 5 pages, 4 figure
Magnetic properties of the honeycomb oxide NaCoTeO
We have studied the magnetic properties of NaCoTeO, which
features a honeycomb lattice of magnetic Co ions, through macroscopic
characterization and neutron diffraction on a powder sample. We have shown that
this material orders in a zig-zag antiferromagnetic structure. In addition to
allowing a linear magnetoelectric coupling, this magnetic arrangement displays
very peculiar spatial magnetic correlations, larger in the honeycomb planes
than between the planes, which do not evolve with the temperature. We have
investigated this behavior by Monte Carlo calculations using the
-- model on a honeycomb lattice with a small interplane
interaction. Our model reproduces the experimental neutron structure factor,
although its absence of temperature evolution must be due to additional
ingredients, such as chemical disorder or quantum fluctuations enhanced by the
proximity to a phase boundary.Comment: 9 pages, 13 figure
Formation of collective spins in frustrated clusters
Using magnetization, specific heat and neutron scattering measurements, as
well as exact calculations on realistic models, the magnetic properties of the
\lacuvo compound are characterized on a wide temperature range. At high
temperature, this oxide is well described by strongly correlated atomic =1/2
spins while decreasing the temperature it switches to a set of weakly
interacting and randomly distributed entangled pseudo spins and
. These pseudo-spins are built over frustrated clusters, similar to
the kagom\'e building block, at the vertices of a triangular superlattice, the
geometrical frustration intervening then at different scales.Comment: 10 page
Magnetic dipolar ordering and quantum phase transition in Fe8 molecular magnet
We show that a crystal of mesoscopic Fe8 single molecule magnets is an
experimental realization of the Quantum Ising Phase Transition (QIPT) model in
a transverse field, with dipolar interactions. Quantum annealing has enabled us
to explore the QIPT at thermodynamical equilibrium. The phase diagram and
critical exponents we obtain are compared to expectations for the mean-field
QIPT Universality class.Comment: 5 pages 4 figure
Effect of HER2 Expression on NUPL2 Protein in Cervical Cancer Cells
Recurring cervical cancer patients frequently present overexpressed Human Epidermal Growth Factor Receptor 2 (HER2) protein, which promotes the growth of the cancer. Some HER2-expressing cells and cervical cancer patients have enhanced gene expression of Nucleoporin-like 2 (NUPL2). As part of the nuclear pore complex, the NUPL2 protein serves to selectively export substances from the nucleus to the cytoplasm. In this experiment, HER2 was expressed in cervical cancer cells to examine its effect on NUPL2 protein expression and localization. Interestingly, there was no difference in NUPL2 protein levels between HER2-expressing and non-expressing cells. Importantly, consistent instances of NUPL2 protein localization specific to the nucleus occurred in a large sampling of HER2-expressing cells. This is significant because it suggests a mechanism as to how HER2 promotes excessive cell growth, via changes in NUPL2 localization, potentially impacting its function and ability to selectively export substances that modulate cell growth
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