Inferring high-resolution human mixing patterns for disease modeling.

Mathematical and computational modeling approaches are increasingly used as quantitative tools in the analysis and forecasting of infectious disease epidemics. The growing need for realism in addressing complex public health questions is, however, calling for accurate models of the human contact patterns that govern the disease transmission processes. Here we present a data-driven approach to generate effective population-level contact matrices by using highly detailed macro (census) and micro (survey) data on key socio-demographic features. We produce age-stratified contact matrices for 35 countries, including 277 sub-national administratvie regions of 8 of those countries, covering approximately 3.5 billion people and reflecting the high degree of cultural and societal diversity of the focus countries. We use the derived contact matrices to model the spread of airborne infectious diseases and show that sub-national heterogeneities in human mixing patterns have a marked impact on epidemic indicators such as the reproduction number and overall attack rate of epidemics of the same etiology. The contact patterns derived here are made publicly available as a modeling tool to study the impact of socio-economic differences and demographic heterogeneities across populations on the epidemiology of infectious diseases.

HPLC-CUPRAC post-column derivatization method for the determination of antioxidants: a performance comparison between porous silica and core-shell column packing.

BACKGROUND: An HPLC method employing a post-column derivatization strategy using the cupric reducing antioxidant capacity reagent (CUPRAC reagent) for the determining antioxidants in plant-based materials leverages the separation capability of regular HPLC approaches while allowing for detection specificity for antioxidants. METHODS: Three different column types, namely core-shell and porous silica including two chemically different core-shell materials (namely phenyl-hexyl and C18), were evaluated to assess potential improvements that could be attained by changing from a porous silica matrix to a core-shell matrix. Tea extracts were used as sample matrices for the evaluation specifically looking at catechin and epigallocatechin gallate (EGCG). RESULTS: Both the C18 and phenyl-hexyl core-shell columns showed better performance compared to the C18 porous silica one in terms of separation, peak shape, and retention time. Among the two core-shell materials, the phenyl-hexyl column showed better resolving power compared to the C18 column. CONCLUSIONS: The CUPRAC post-column derivatization method can be improved using core-shell columns and suitable for quantifying antioxidants, exemplified by catechin and EGCG, in tea samples.

Experimental and Theoretical Aspects of Anion Complexes with a Thiophene-Based Cryptand.

Selective recognition of anions has received a tremendous attention in recent years because of their significant importance in biology and environment. This article highlights our recent research on a thiophene-based azacryptand that has been shown to effectively bind anions including iodide, bromide, chloride, nitrate and sulfate. Structural studies indicate that the ligand forms inclusion complexes with chloride and iodide. On the other hand, it forms cleft-like complexes with nitrate and sulfate, where three anions are bound between the cyclic arms. The ligand binds each anion with a 1:1 binding mode in water, exhibiting strong selectivity for sulfate; which is further supported by ESI-MS and DFT calculations.

Solution and structural binding studies of phosphate with thiophene-based azamacrocycles.

Two thiophene-based monocyclic receptors L1 and L2 have been studied for phosphate binding in solutions (D2O and DMSO-d6 ) by 1H NMR and 31P NMR titrations, and in the solid state by single crystal X-ray analysis. Results from 1H NMR titrations suggest that the ligands bind phosphate anions in a 1:2 binding mode in DMSO-d6 , with the binding constants of 5.25 and 4.20 (in log K), respectively. The binding of phosphate to L1 and L2 was further supported by 31P NMR in D2O at pH = 5.2. The crystal structure of the phosphate complex of L1 reveals unambiguous proof for the formation of a ditopic complex via multiple hydrogen bonds from NH···O and CH···O interactions.

Colorimetric and Optical Discrimination of Halides by a Simple Chemosensor.

A thiophene-based tripodal copper(II) complex has been synthesized as a new colorimetric and optical chemosensor for naked-eye discrimination of halides in acetonitrile and an acetonitrile-water mixture. The binding interactions of the new receptor with several anions were analyzed by UV-Vis titrations, electrospray ionization mass spectrometric (ESI-MS) experiments and density functional theory (DFT) calculations. The results from UV-Vis titrations indicate that the coordinative unsaturated copper(II) complex strongly binds a halide at its vacant copper(II) centre via a metal-ligand bond forming a 1:1 complex, exhibiting binding affinities in the order of fluoride > chloride > bromide > iodide. The interactions of the receptor with halides were further confirmed by ESI-MS, showing a distinct signal corresponding to a 1:1 complex for each halide, suggesting that the noncovalent interactions also exist in the gas phase. In addition, time-dependent DFT (TD-DFT) calculations were also carried out to understand the excited-state properties of the chemosensor complexes. A detailed analysis of the TD-DFT calculations shows a consistent red-shift in the first optically-allowed transition, consistent with the observed colorimetric experiments.

Crystal structure of 5,5'-bis-(di-methyl-amino)-N,N'-(3-methyl-3-aza-pentane-1,5-di-yl)di(naphthalene-1-sulfonamide).

In the title compound, C29H37N5O4S2, two arms substituted with dansyl derivatives are connected to a central tertiary amine, where the dihedral angle between the planes of two dansyl units is 56.39 (4)°. Each arm contains a sulfonamide functional group and both N-H groups in the compound are pointed to the same side. The central part of the mol-ecule is disordered over three sets of sites with a refined occupancy ratio of 0.547 (4):0.328 (4):0.125 (3). No intra-molecular π-π or hydrogen-bonding inter-actions are observed. In the crystal, mol-ecules are linked via pairs of N-H⋯O inter-actions involving the same acceptor atom, forming inversion dimers. In addition, C-H⋯O inter-actions exist between molecules, providing further stabilization of dimers.

Molecular Recognition of Perchlorate Anion With a Cryptand-Based Synthetic Receptor.

Perchlorate anion is a highly toxic environmental contaminant, which is implicated in various health related problems. This paper reports a cryptand-based synthetic molecule (L) prepared from the reaction of tris (2-aminoethyl) amine and 2,5-thiophenedicarboxaldehyde under a high dilution condition, providing a well-defined cavity for a guest species. The hexaprotonated receptor [H6L]6+ has been obtained from the addition of six equivalents of tosylic acid to L, which has been studied for perchlorate anion by proton NMR studies in water. The results demonstrate that the receptor strongly binds the negatively charged perchlorate via hydrogen bonding and electrostatic interactions in solution forming a supramolecular anion complex. This molecule can be useful for the future application in the environmental remediation of toxic perchlorate anion.

N (1)-(Thio-phen-2-ylmeth-yl)-N (3),N (3)-bis-[3-(thio-phen-2-yl-methyl-ammonio)-prop-yl]propane-1,3-di-ammonium hexa-fluorido-silicate methanol tris-olvate.

In the title compound, C24H40N4S3 (4+)·2SiF6 (2-)·3CH3OH, the central tertiary amine function is protonated and is connected to three thio-phen-2-yl-methyl-amino-n-propyl groups, forming the arms of a T-shaped cation that has two pockets. Each arm contains one protonated secondary amine function, and each pocket is occupied by one SiF6 (2-) anion bonded via two N-H⋯F inter-actions with the protonated amine group on the middle arm, while two methanol solvent mol-ecules are N-H⋯O hydrogen-bonded with the other secondary protonated amine groups on the side arms. Weak O-H⋯O and O-H⋯F hydrogen bonds between the solvent mol-ecules and between the solvent mol-ecules and the anions, respectively, are also observed. All three thio-phene groups in the arms are disordered over two sets of sites, with occupancy ratios of 0.828 (3):0.172 (3), 0.910 (2):0.090 (2) and 0.890 (3):0.110 (3).

A self-assembled fluoride-water cyclic cluster of [F(H2O)]4(4-) in a molecular box.

We present an unprecedented fluoride-water cyclic cluster of [F(H(2)O)](4)(4-) assembled in a cuboid molecular box formed by two large macrocycles. Structural characterization reveals that [F(H(2)O)](4)(4-) is assembled by strong H-bonding interactions [OH···F = 2.684(3)-2.724(3) Å], where a fluoride anion plays the topological role of a water molecule in the classical cyclic water octamer. The interaction of fluoride was further confirmed by (19)F NMR and (1)H NMR spectroscopies, indicating the encapsulation of the anionic species within the cavity in solution. High-level DFT calculations and Bader topological analyses fully support the crystallographic results, demonstrating that the bonding arrangement in the fluoride-water cluster arises from the unique geometry of the host.