60 research outputs found
Uranyl Peroxide Oxalate Cage and Core–Shell Clusters Containing 50 and 120 Uranyl Ions
Cage clusters built from uranyl hexagonal bipyramids
and oxalate
ligands crystallize from slightly acidic aqueous solution under ambient
conditions, facilitating structure analysis. Each cluster contains
uranyl ions coordinated by peroxo ligands in a bidentate configuration.
Uranyl ions are bridged by shared peroxo ligands, oxalate ligands,
or through hydroxyl groups. U<sub>50</sub>Ox<sub>20</sub> contains
50 uranyl ions and 20 oxalate groups and is a topological derivative
of the U<sub>50</sub> cage cluster that has a fullerene topology.
U<sub>120</sub>Ox<sub>90</sub> contains 120 uranyl ions and 90 oxalate
groups and is the largest and highest mass cluster containing uranyl
ions that has been reported. It has a core–shell structure,
in which the inner shell (core) consists of a cluster of 60 uranyl
ions and 30 oxalate groups, identical to U<sub>60</sub>Ox<sub>30</sub>, with a fullerene topology. The outer shell contains 12 identical
units that each consist of five uranyl hexagonal bipyramids that are
linked to form a ring (topological pentagon), with each uranyl ion
also coordinated by a side-on nonbridging oxalate group. The five-membered
rings of the inner and outer shells (the topological pentagons) are
in correspondence and are linked through K cations. The inner shell
topology has therefore templated the location of the outer shell rings,
and the K counterions assume a structure-directing role. Small-angle
X-ray scattering data demonstrated U<sub>50</sub>Ox<sub>20</sub> remains
intact in aqueous solution upon dissolution. In the case of clusters
of U<sub>120</sub>Ox<sub>90</sub>, the scattering data for dissolved
crystals indicates the U<sub>60</sub>Ox<sub>30</sub> core persists
in solution, although the outer rings of uranyl bipyramids contained
in the U<sub>120</sub>Ox<sub>90</sub> core–shell cluster appear
to detach from the cluster when crystals are dissolved in water
Uranyl Peroxide Oxalate Cage and Core–Shell Clusters Containing 50 and 120 Uranyl Ions
Cage clusters built from uranyl hexagonal bipyramids
and oxalate
ligands crystallize from slightly acidic aqueous solution under ambient
conditions, facilitating structure analysis. Each cluster contains
uranyl ions coordinated by peroxo ligands in a bidentate configuration.
Uranyl ions are bridged by shared peroxo ligands, oxalate ligands,
or through hydroxyl groups. U<sub>50</sub>Ox<sub>20</sub> contains
50 uranyl ions and 20 oxalate groups and is a topological derivative
of the U<sub>50</sub> cage cluster that has a fullerene topology.
U<sub>120</sub>Ox<sub>90</sub> contains 120 uranyl ions and 90 oxalate
groups and is the largest and highest mass cluster containing uranyl
ions that has been reported. It has a core–shell structure,
in which the inner shell (core) consists of a cluster of 60 uranyl
ions and 30 oxalate groups, identical to U<sub>60</sub>Ox<sub>30</sub>, with a fullerene topology. The outer shell contains 12 identical
units that each consist of five uranyl hexagonal bipyramids that are
linked to form a ring (topological pentagon), with each uranyl ion
also coordinated by a side-on nonbridging oxalate group. The five-membered
rings of the inner and outer shells (the topological pentagons) are
in correspondence and are linked through K cations. The inner shell
topology has therefore templated the location of the outer shell rings,
and the K counterions assume a structure-directing role. Small-angle
X-ray scattering data demonstrated U<sub>50</sub>Ox<sub>20</sub> remains
intact in aqueous solution upon dissolution. In the case of clusters
of U<sub>120</sub>Ox<sub>90</sub>, the scattering data for dissolved
crystals indicates the U<sub>60</sub>Ox<sub>30</sub> core persists
in solution, although the outer rings of uranyl bipyramids contained
in the U<sub>120</sub>Ox<sub>90</sub> core–shell cluster appear
to detach from the cluster when crystals are dissolved in water
A. Relationship between modeled NPP and observed NPP. B. Relationship between modeled NPP and other evaluations.
<p>A. Relationship between modeled NPP and observed NPP. B. Relationship between modeled NPP and other evaluations.</p
Difference analysis of ecosystem service values (ESVs) in the national nature reserves in Ningxia in 2000, 2005 and 2010.
<p>Difference analysis of ecosystem service values (ESVs) in the national nature reserves in Ningxia in 2000, 2005 and 2010.</p
Areas of land use types in the national nature reserves in Ningxia in 2000, 2005, and 2010.
<p>Areas of land use types in the national nature reserves in Ningxia in 2000, 2005, and 2010.</p
Distribution of land use types during 2000–2010.
<p>Distribution of land use types during 2000–2010.</p
Equivalent value per unit area of ecosystem services in China [26].
<p>Equivalent value per unit area of ecosystem services in China <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0089174#pone.0089174-Xie1" target="_blank">[26]</a>.</p
Dynamic rates of each land use type during 2000–2010.
<p>Dynamic rates of each land use type during 2000–2010.</p
Interaction of Ionic Liquids with a Lipid Bilayer: A Biophysical Study of Ionic Liquid Cytotoxicity
Ionic liquids (ILs) have been widely
considered and used as “green
solvents” for more than two decades. However, their ecotoxicity
results have contradicted this view, as ILs, particularly hydrophobic
ones, are reported to exhibit high toxicity. Yet the origin of their
toxicology remains unclear. In this work, we have investigated the
interaction of amphiphilic ILs with a lipid bilayer as a model cell
membrane to understand their cytotoxicity at a molecular level. By
employing fluorescence imaging and light and X-ray scattering techniques,
we have found that amphiphilic ILs could disrupt the lipid bilayer
by IL insertion, end-capping the hydrophobic edge of the lipid bilayer,
and eventually disintegrating the lipid bilayer at high IL concentration.
The insertion of ILs to cause the swelling of the lipid bilayer shows
strong dependence on the hydrophobicity of IL cationic alky chain
and anions and is strongly correlated with the reported IL cytotoxicity
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