No abstract

Many industrial processes produce waste with toxic and precious metal pollutants. Current remediation strategies lack the selectivity needed to effectively eliminate heavy metals. Thus, materials are needed to effectively treat waste streams and contaminated waterways. Sulfur is well known for its ability to selectively bind heavy metals. Additionally, excess sulfur is produced on large scales during petroleum refinement making it inexpensive and abundant. Inverse vulcanization enables surplus sulfur to be repurposed into high sulfur content materials without the need for solvents. These polysulfides have demonstrated many beneficial applications including heavy metal binding. However, they are plagued by low solubility and dominated by hydrophobic monomers. Here, elemental sulfur and charged monomers, including diallyl dimethylammonium chloride (DADMAC), were combined for the first time in a one-step reaction forming water-soluble polysulfides. The water solubility allows for complete interaction of dissolved metal ions with the polymer, rather than surface-level interaction as is the case for traditional inverse vulcanized polymers. Additionally, the charged polysulfides exhibit enhanced solubility in organic solvents, making solution-based characterization such as NMR more accurate. Poly­(S-DADMAC) has demonstrated selective binding to gold and silver inducing the formation of a macromolecular complex that precipitates from solution. Additionally, these polymers interact with other heavy metals including lead and copper demonstrating a visible color change at low concentrations that may be used to detect the presence of these metals in wastewater. The low cost, ease of preparation, and scalability make these polysulfides practical as well as functional.

Our results confirm the clinical value of fetal DNA measurement in maternal plasma during the second trimester as a supplement for the diagnosis of aneuploidies. Its use as a screening instrument for complications that develop later in pregnancy seems to be limited but needs further investigation. Although the QF-PCR assay has the advantage of being applicable to both female and male fetuses, this approach cannot be used for quantitation of cff DNA in maternal plasma samples.

Our data confirm that cff-DNA is cleared by the kidneys in detectable amounts, but due to its low concentration or problematic detection in maternal urine this source seems inappropriate for noninvasive prenatal diagnosis.

The most common conjunctival bacteria in newborns delivered by either vaginal birth or C-section were coagulase-negative Staphylococcus. The proportion of positive conjunctival cultures was higher for infants delivered vaginally than for C-section delivery.