The homotopy groups πi(S0) of the 0-dimensional sphere are trivial for i > 0, because any base point preserving map from an i-sphere to a 0-sphere is a one-point mapping.
More generally, the i-th homotopy group, πi(X) begins with the pointed i-sphere (Si,s), and otherwise follows the same procedure.
The reason is that a continuous mapping from an i-sphere to an n-sphere with i n with a point removed; this is a contractible space, and any mapping to such a space can be deformed into a one-point mapping.
This alginate-nZVI sphere exhibited good separability in effective removal of Cr VI).
Hence, the alginate-nZVI sphere might be a promising agent for an emergent Cr VI) spill treatment by enhancing the dispersion, stabilization and separation properties of nZVI.
In this study, we designed and fabricated a hierarchical, ordered and macroporous structured alginate sphere to support in-situ synthesized zero-valent iron nanoparticle (the alginate-nZVI sphere).
In addition, the alginate-nZVI sphere was effective in Cr VI) removal in a wide range of pH from 3.0 to 11.0, by the merit of alginate substrate.
I see spheres of danger everywhere I look.... Tell me, Father, something useful about what I see".
Blue mesh, mFo-DFc omit map for GE (contoured at 2.5σ); blue sticks, GE; gray ribbons, RNAP backbone; green surfaces, RNAP residues at which substitutions confer GE-resistance; cyan sticks, additional RNAP residues that contact GE; gray and red sticks additional RNAP residues that coordinate Mg2+(I); violet sphere, Mg2+(I).
