Predicting Concentration- and Ionic-Strength-Dependent Air-Water Interfacial Partitioning Parameters of PFASs Using Quantitative Structure-Property Relationships (QSPRs).

Air-water interfacial retention of poly- and perfluoroalkyl substances (PFASs) is increasingly recognized as an important environmental process. Herein, column transport experiments were used to measure air-water interfacial partitioning values for several perfluoroalkyl ethers and for PFASs derived from aqueous film-forming foam, while batch experiments were used to determine equilibrium Kia data for compounds exhibiting evidence of rate-limited partitioning. Experimental results suggest a Freundlich isotherm best describes PFAS air-water partitioning at environmentally relevant concentrations (101-106 ng/L). A multiparameter regression analysis for Kia prediction was performed for the 15 PFASs for which equilibrium Kia values were determined, assessing 246 possible combinations of 8 physicochemical and system properties. Quantitative structure-property relationships (QSPRs) based on three to four parameters provided predictions of high accuracy without model overparameterization. Two QSPRs (R2 values of 0.92 and 0.83) were developed using an assumed average Freundlich n value of 0.65 and validated across a range of relevant concentrations for perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), and hexafluoropropylene oxide-dimer acid (i.e., GenX). A mass action model was further modified to account for the changing ionic strength on PFAS air-water interfacial sorption. The final result was two distinct QSPRs for estimating PFAS air-water interfacial partitioning across a range of aqueous concentrations and ionic strengths.

[PtZn2Ge18(Hyp)8] (Hyp = Si(SiMe3)3): A Neutral Polynuclear Chain Compound with Ge9(Hyp)3 Units.

The reaction of [ZnGe18(Hyp)6] (Hyp = Si(SiMe3)3) with Pt(PPh3)4 gives the neutral polynuclear complex of Ge9(Hyp)3 units [HypZn-Ge9(Hyp)3-Pt-Ge9(Hyp)3-ZnHyp], 1. Within 1, the central Pt atom is bound η3 to both Ge9(Hyp)3 units to which further ZnHyp units are bound again, symmetric η3, to the other side of the Ge9(Hyp)3 units, leading to the longest chain compound exhibiting Ge9(Hyp)3 units that is known to date. Dissolved crystals of 1 give a violet solution, showing an absorption maximum around 543 nm. Further UV-vis investigations on different M xGe9(Hyp)3 compounds show that the absorption maximum depends on the number of transition metal atoms bound to the Ge9(Hyp)3 unit, which is supported by TD-DFT calculations.

Safety and immunogenicity of Nanocovax, a SARS-CoV-2 recombinant spike protein vaccine: Interim results of a double-blind, randomised controlled phase 1 and 2 trial.

Background: Nanocovax is a recombinant severe acute respiratory syndrome coronavirus 2 subunit vaccine composed of full-length prefusion stabilized recombinant SARS-CoV-2 spike glycoproteins (S-2P) and aluminium hydroxide adjuvant. Methods: We conducted a dose-escalation, open label trial (phase 1) and a randomized, double-blind, placebo-controlled trial (phase 2) to evaluate the safety and immunogenicity of the Nanocovax vaccine (in 25 mcg, 50 mcg, and 75 mcg doses, aluminium hydroxide adjuvanted (0·5 mg/dose) in 2-dose regime, 28 days apart (ClinicalTrials.gov number, NCT04683484). In phase 1, 60 participants received two intramuscular injection of the vaccine following dose-escalation procedure. The primary outcomes were reactogenicity and laboratory tests to evaluate the vaccine safety. In phase 2, 560 healthy adults received either vaccine doses similar in phase 1 (25 or 50 or 75 mcg S antigen in 0·5 mg aluminium per dose) or adjuvant (0·5 mg aluminium) in a ratio of 2:2:2:1. One primary outcome was the vaccine safety, including solicited adverse events for 7 day and unsolicited adverse events for 28 days after each injection as well as serious adverse event or adverse events of special interest throughout the study period. Another primary outcome was anti-S IgG antibody response (Index unit/ml). Secondary outcomes were surrogate virus neutralisation (inhibition percentage), wild-type SARS-CoV-2 neutralisation (dilution fold), and T-cell responses by intracellular staining for interferon gamma (IFNg). Anti-S IgG and neutralising antibody levels were compared with convalescent serum samples from symptomatic Covid-19 patients. Findings: For phase 1 study, no serious adverse events were observed for all 60 participants. Most adverse events were grade 1 and disappeared shortly after injection. For phase 2 study, after randomisation, 480 participants were assigned to receive the vaccine with adjuvant, and 80 participants were assigned to receive the placebo (adjuvant only). Reactogenicity was absent or mild in the majority of participants and of short duration (mean ≤3 days). Unsolicited adverse events were mild in most participants. There were no serious adverse events related to Nanocovax. Regarding the immunogenicity, Nanocovax induced robust anti-S antibody responses. In general, there humoral responses were similar among vaccine groups which reached their peaks at day 42 and declined afterward. At day 42, IgG levels of vaccine groups were 60·48 [CI95%: 51·12-71·55], 49·11 [41·26-58·46], 57·18 [48·4-67·5] compared to 7·10 [6·32-13·92] of convalescent samples. IgG levels reported here can be converted to WHO international standard binding antibody unit (BAU/ml) by multiplying them to a conversion factor of 21·8. Neutralising antibody titre of vaccine groups at day 42 were 89·2 [52·2-152·3], 80·0 [50·8-125.9] and 95·1 [63·1-143·6], compared to 55·1 [33·4-91·0] of the convalescent group. Interpretation: Up to day 90, Nanocovax was found to be safe, well tolerated, and induced robust immune responses. Funding: This work was funded by the Coalition for Epidemic Preparedness Innovations (CEPI), the Ministry of Science and Technology of Vietnam, and Nanogen Pharmaceutical Biotechnology JSC.

Evaluating peats for their capacities to extract methyl tertiary butyl ether from contaminated water using solid-phase microextraction with gas chromatography.

Methyl tertiary butyl ether (MTBE), the most common fuel additive used to oxygenate gasoline, is being detected more frequently in drinking water supplies. This research investigates the capacities of 10 different types of highly characterized peats to extract MTBE from contaminated water. Peat samples were slurried for 24 hours under controlled conditions in aqueous solutions of MTBE. Liquid portions of the samples were analyzed for MTBE concentrations using a Solid-phase Microextraction GC/MS (SPME-GC/MS) method and were compared to samples of the MTBE solution (without peat addition) to determine the peats' MTBE sorption capacities. The SPME-GC/MS results indicate that all peats tested worked well at extracting MTBE from an aqueous solution. Although this was so, some peats tended to work better than others. The Loxahatchee Nymphaea and the Maine Sphagnum peats worked best, producing 92 and 88% MTBE reductions, respectively, while the Okefenokee Taxodium and the New York peats achieved the poorest results, producing only 50 and 47% MTBE reductions, respectively. In addition, the peats derived from herbaceous vegetation worked better than those derived from woody plants (except for the woody North Carolina peat). Overall, the peats that were the most effective at extracting MTBE from water tended to have higher hydraulic conductivities, microporosities, macroporosities, total porosities, and water holding capacities, but lower bulk densities, total ash contents, Ti contents, P contents, Si contents, K contents, Al contents, fulvic acid contents, total guaiacyl lignin contents, and total other ketones contents. Peats with higher MTBE extraction capacities also had humic acids contents that ranged between 4.6-7.1%. These results suggest that peats could be used as filtration, or sorption, media to remediate surface water or groundwater that is contaminated with MTBE. SPME-GC/MS analysis was found to be a reasonably inexpensive and efficient way to evaluate MTBE sorption capacities of peat samples.