Comprehensive analysis of metal(loid)s and associated metal(loid) resistance genes in atmospheric particulate matter.

Despite global concerns about metal(loid)s in atmospheric particulate matter (PM), the presence of metal(loid) resistance genes (MRGs) in PM remains unknown. Therefore, we conducted a comprehensive investigation of the metal(loid)s and associated MRGs in PMs in two seasons (summer and winter) in Xiamen, China. According to the geoaccumulation index (I), most metal(loid)s, except for V and Mn, exhibited enrichment in PM, suggesting potential anthropogenic sources.

Insights into long-term changes of groundwater levels in the typical region of Zhangjiakou City, China.

Little information is available on the long-term changes of groundwater levels and their associated influencing factors. Zhangjiakou City was chosen as a case to reveal the temporal and spatial dynamics of groundwater level and its driving factors in the long term. Herein, the observation data of groundwater level from 56 wells was investigated from 1981 to 2015, including the collected meteorological data, socio-economic data, and groundwater resource exploitation situation.

Elevated nano-α-FeO enhances arsenic metabolism and dissolved organic carbon release of Microcystis aeruginosa under a phytate environment.

Little information is available on the effects of nano-α-FeO on arsenic (As) metabolism of algae and potential associated carbon (C) storage in As-contaminated water with dissolved organic phosphorus (DOP) as a phosphorus (P) source. In this study, Microcystis aeruginosa (M. aeruginosa) was used to investigate impacts of nano-α-FeO on cell growth and As metabolism of algae under a phytate (PA) environment as well as potential associated C storage.

Orientational Dependence of Cofacial Porphyrin-Quinone Electronic Interactions within the Strong Coupling Regime.

We examine the relative magnitudes of electronic coupling in two face-to-face rigid and diastereomeric (porphinato)zinc(II)-quinone (PZn-Q) assemblies, and , in which the six quinonyl carbon atoms lie in virtually identical arrangements relative to the PZn plane at sub-van der Waals donor-acceptor (D-A) interplanar separations. Steady-state and time-resolved transient optical data and computational studies show that minor differences in relative D-A cofacial orientation give rise to disparate magnitudes for both photoinduced charge separation (CS) and thermal charge recombination (CR). Time-dependent density functional theory (TDDFT) computations illuminate the nature of direct charge transfer states and the electronic structural factors that give rise to these differential s.

Two-photon absorption properties of proquinoidal D-A-D and A-D-A quadrupolar chromophores.

We report the synthesis, one- and two-photon absorption spectroscopy, fluorescence, and electrochemical properties of a series of quadrupolar molecules that feature proquinoidal π-aromatic acceptors. These quadrupolar molecules possess either donor-acceptor-donor (D-A-D) or acceptor-donor-acceptor (A-D-A) electronic motifs, and feature 4-N,N-dihexylaminophenyl, 4-dodecyloxyphenyl, 4-(N,N-dihexylamino)benzo[c][1,2,5]thiadiazolyl or 2,5-dioctyloxyphenyl electron donor moieties and benzo[c][1,2,5]thiadiazole (BTD) or 6,7-bis(3',7'-dimethyloctyl)[1,2,5]thiadiazolo[3,4-g]quinoxaline (TDQ) electron acceptor units. These conjugated structures are highly emissive in nonpolar solvents and exhibit large spectral red-shifts of their respective lowest energy absorption bands relative to analogous reference compounds that incorporate phenylene components in place of BTD and TDQ moieties.

Generalized Mulliken-Hush analysis of electronic coupling interactions in compressed pi-stacked porphyrin-bridge-quinone systems.

Donor-acceptor interactions were investigated in a series of unusually rigid, cofacially compressed pi-stacked porphyrin-bridge-quinone systems. The two-state generalized Mulliken-Hush (GMH) approach was used to compute the coupling matrix elements. The theoretical coupling values evaluated with the GMH method were obtained from configuration interaction calculations using the INDO/S method.

The degree of charge transfer in ground and charge-separated states revealed by ultrafast visible pump/mid-IR probe spectroscopy.

We demonstrate a new femtosecond visible pump/mid-IR probe spectroscopic approach to assess directly the ground- and excited-state degrees of charge transfer (CT) in donor-spacer-acceptor (D-Sp-A) structures. Two classes of (porphinato)zinc(II) (PZn)-based D-Sp-A compounds with either quinonyl (Q) or N-(N'-octyl)pyromellitic diimide (PI) electron acceptors were interrogated. Carbonyl antisymmetric stretching mode frequency domain transient-IR spectra of these species were recorded and analyzed for the Q/PI moieties.