Highlights The Abbott IgM assay against SARS-CoV-2 is detected slightly earlier compared to IgG. Both Abbott IgM and IgG assays exhibit excellent sensitivity and specificity. Positive rate of IgM drops to 30.8% after 3 months of symptoms, in contrast to IgG which is sustained in 92.3% patients 3-6 months post symptom onset. In symptomatic patients who test negative by PCR for a SARS-CoV-2 infection, assessing IgM and IgG antibodies can aid in supporting a diagnosis of COVID-19.

Hydrothermal synthesis has afforded a family of five divalent metal succinate (suc) coordination polymers incorporating the kinked dipodal organodiimine 4,4′-dipyridylamine (dpa), which were structurally characterized by single-crystal X-ray diffraction and thermogravimetric analysis. [Co(suc)(dpa) 2 ] (1) manifests chiral helical one-dimensional (1-D) chains formed from the linkage of neighboring Co atoms through bischelating bisbridging succinate moieties, with pendant dpa ligands. {[Ni(dpa) 2 -(suc) 0.5 ]Cl} (2) possesses a rare self-interpenetrated 5-connected cationic framework with a unique 6 10 topology, constructed from the junction of quadruply interpenetrated adamantoid [Ni(dpa) 2 ] 2n+ networks via bischelating µ 2 -succinate ligands. {[Cu(suc)-(dpa)]‚0.5H 2 O} (3) exhibits a doubly interpenetrated CdSO 4 net (6 5 8 topology) containing both 1-D double braided cationic helical [Cu(dpa)] 2+ ribbons and orthogonally situated zigzag [Cu(suc)] chains. The quadruply interpenetrated three-dimensional (3-D) network structure (4 2 6 3 8 topology, SrAl 2 -type) of {[Zn(suc) 0.5/2 (dpa)]‚H 2 O} ( 4) is built from [Zn(suc) 0.5/2 ] chains interlocked with dpa tethers. {[Cd(suc)(dpa)]‚H 2 O} (5) displays doubly interpenetrated 6-connected R-Po networks based on {Cd 2 O 2 } dimers within [Cd(suc)] two-dimensional (2-D) layers, in turn pillared by dpa ligands. The coordination geometry about the metal atoms and the succinate binding modes and conformations in these compounds vary widely, playing a significant role in promoting the diversity of the observed structural motifs. Supramolecular hydrogen-bonding interactions through the dpa amine subunit are evident in all cases.

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We present an in-depth electrical characterization of contact resistance in carbon nanostructure via interconnects. Test structures designed and fabricated for via applications contain vertically aligned arrays of carbon nanofibers (CNFs) grown on a thin titanium film on silicon substrate and embedded in silicon dioxide. Current-voltage measurements are performed on single CNFs using atomic force microscope current-sensing technique. By analyzing the dependence of measured resistance on CNF diameter, we extract the CNF resistivity and the metal-CNF contact resistance.

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