Murphymullen2696

Metal heteroanionic materials, such as oxyhalides, are promising photocatalysts in which band positions can be engineered for visible-light absorption by changing the halide identity. Advancing the synthesis of these materials, bismuth oxyhalides of the form BiOX (X = Cl, Br) have been prepared using rapid and scalable ultrasonic spray synthesis (USS). Central to this advance was the identification of small organohalide molecules as halide sources. When these precursors are spatially and temporally confined in the aerosol phase with molten salt fluxes, powders composed of single-crystalline BiOX nanoplates can be produced continuously. A mechanism highlighting the in situ generation of halide ions is proposed. These materials can be used as photocatalysts and provide proof-of-concept toward USS as a route to more complex bismuth oxyhalide materials.Non-heme iron complexes with cis-FeIII(OH)(SAr/OAr) coordination were isolated and examined for their reactivity with a tertiary carbon radical. The sulfur-ligated complex shows a temperature dependence on •OH versus ArS• transfer, whereas the oxygen-ligated complex does not. These results provide the first working model for C-S bond formation in isopenicillin N synthase and indicate that kinetic control may be a key factor in the selectivity of non-heme iron "rebound" processes.The solution-state interactions between octadentate hydroxypyridinone (HOPO) and catecholamide (CAM) chelating ligands and uranium were investigated and characterized by UV-visible spectrophotometry and X-ray absorption spectroscopy (XAS), as well as electrochemically via spectroelectrochemistry (SEC) and cyclic voltammetry (CV) measurements. Depending on the selected chelator, we demonstrate the controlled ability to bind and stabilize UIV, generating with 3,4,3-LI(1,2-HOPO), a tetravalent uranium complex that is practically inert toward oxidation or hydrolysis in acidic, aqueous solution. At physiological pH values, we are also able to bind and stabilize UIV to a lesser extent, as evidenced by the mix of UIV and UVI complexes observed via XAS. CV and SEC measurements confirmed that the UIV complex formed with 3,4,3-LI(1,2-HOPO) is redox inert in acidic media, and UVI ions can be reduced, likely proceeding via a two-electron reduction process.A novel nonprecious Fe2O3 nanoparticle decorated NiO nanosheet (Fe2O3 NPs@NiO NSs) composite has been obtained by a rapid one-pot electrochemical exfoliation method and can be used as an efficient oxygen evolution reaction (OER) catalyst. In the nanocomposite, the Fe2O3 NPs are uniformly anchored on the ultrathin graphene-like NiO nanosheets. At the same time, we also studied the influence of the Fe/Ni molar ratio on the morphology and catalytic activity. The Fe2O3 NPs@NiO NSs nanocomposite possessed a high BET surface area (194.1 m2 g-1), which is very conducive to the charge/mass transfer of electrolyte ions and O2. Owing to the unique two-dimensional (2D) heterostructures and rational Fe content, the as-prepared Fe2O3 NPs@NiO NSs show high catalytic performance, a low overpotential at 10 mA cm-2 (221 mV), a small Tafel slope (53.4 mV dec-1), and 2000 cycle and 20 h long-term durability. The introduction of Fe2O3 NPs is beneficial to accelerating charge transport, increasing the electrochemically active surface area (ECSA), and thus improving the release of oxygen bubbles from the electrode surface.The rapid emergence of antibiotic resistance genes (ARGs) has become an increasingly serious threat to public health. Previous studies illustrate the antibiotic-like effect of many substances. However, whether and how commonly used or existing non-antibiotic metalloids (e.g., selenate) would enhance ARG spread remains poorly known. Here, we tracked the long-term operation of a bioreactor continuously fed with selenate for more than 1000 days. Metagenomic sequencing identified 191 different ARGs, of which the total abundance increased significantly after the amendment of selenate. Network analyses showed that ARGs resisting multiple drugs had very similar co-occurrence patterns, implying a potentially larger health risk. Host classification not only indicated multidrug-resistant species but also distinguished the mechanism of ARG enrichment for vertical transfer and horizontal gene transfer. Genome reconstruction of an ARG host suggested that selenate and its bioreduction product selenite could stimulate the overproduction of intracellular reactive oxygen species, which was confirmed by the direct measurement. Bacterial membrane permeability, type IV pilus formation, and DNA repair and recombination were also enhanced, together facilitating the horizontal acquirement of ARGs. Overall, this study for the first time highlights the ARG emergence and dissemination induced by a non-antibiotic metalloid and identifies ARG as a factor to consider in selenate bioremediation.Climate warming is seldom considered in the transformation of pesticides on a plant leaf. This study investigated the effects of photodegradation temperature and spinach growth temperature from 15 to 21 °C on the photodegradation of bifenthrin, cypermethrin, fenvalerate, and deltamethrin on spinach leaves under xenon lamp irradiation in climate incubators. The photodegradation temperature had minor effects on pyrethroid photodegradation. Interestingly, the photodegradation rates decreased with increasing spinach growth temperature. For example, the photodegradation rate constant of bifenthrin on a spinach cultivated at 15 °C (3.73 (±0.59, 95% confidence level) × 10-2 h-1) was 1.9 times higher than that at 21 °C (1.96 (±0.17) × 10-2 h-1). Hydroxyl radicals (·OH) played a dominant role in the photodegradation. We speculate that ·OH originated from the degradation of hydroperoxide that was formed by oxidation of phenolic CH═CH, aliphatic CH3 and aromatic C-O-C, and subsequent hydrogen abstraction. The contents of these functional groups decreased with increasing growth temperature, which resulted in lower photodegradation rates at higher growth temperatures. A possible photodegradation pathway including ester bond cleavage, decyanation, and phenyl group removal was proposed. This work provides new insight into the effects of climate warming on the generation of reactive oxygen species and the transformation of pesticides on a plant leaf.Mössbauer spectroscopy has been used to characterize oxygenated myoglobins (oxy Mbs) reconstituted with native and chemically modified 57Fe-enriched heme cofactors with different electron densities of the heme Fe atom (ρFe) and to elucidate the effect of a change in the ρFe on the nature of the bond between heme Fe and oxygen (O2), i.e., the Fe-O2 bond, in the protein. Quadrupole splitting (ΔEQ) was found to decrease with decreasing ρFe, and the observed ρFe-dependent ΔEQ confirmed an increase in the contribution of the ferric-superoxide (Fe3+-O2-) form to the resonance hybrid of the Fe-O2 fragment with decreasing ρFe. These observations explicitly accounted for the lowering of O2 affinity of the protein due to an increase in the O2 dissociation rate and a decrease in the autoxidation reaction rate of oxy Mb through decreasing H+ affinity of the bound ligand with decreasing ρFe. Therefore, the present study demonstrated the mechanism underlying the electronic control of O2 affinity and the autoxidation of the protein through the heme electronic structure. Carbon monoxide (CO) adducts of reconstituted Mbs (CO-Mbs) were similarly characterized, and we found that the resonance between the two canonical forms of the Fe-CO fragment was also affected by a change in ρFe. Thus, the nature of the Fe-ligand bond in the protein was found to be affected by the ρFe.Black phosphorus (BP) has extensive applications in various fields. The release of BP into aquatic ecosystems and the potential toxic effects on aquatic organisms are becoming major concerns. Here, we investigated the developmental toxicity of few-layered BP toward the zebrafish. We found that BP could adsorb on the surface of the chorion and could subsequently penetrate within the embryo. After exposure of embryos to 10 mg/L BP, developmental malformations appeared at 96 hpf, especially heart deformities such as pericardial edema and bradycardia, accompanied by severe circulatory system failure. Using transgenic zebrafish larvae, we further characterized cardiovascular defects with cardiac enlargement and impaired cardiac vessels as indicators of damage to the cardiovascular system upon BP exposure. We performed transcriptomic analysis on zebrafish embryos treated with a lower concentration of 2 mg/L. The results showed disruption in genes associated with muscle development, oxygen involved processes, focal adhesion, and VEGF and MAPK signaling pathways. These alterations also indicated that BP carries a risk of developmental perturbation at lower concentrations. This study provides new insights into the effects of BP on aquatic organisms.To determine how the aryl hydrocarbon receptor (AhR) signaling acts along the gut-liver axis, we employed an integrated metagenomic and metabolomic approach to comprehensively profile the microbial and metabolic networks. Adult zebrafish were exposed to a model agonist of the AhR polychlorinated biphenyl (PCB) 126. The metagenomic analysis showed that PCB126 suppressed microbial activities related to primary bile acid metabolism in male intestines. Accordingly, a suite of primary bile acids consistently showed higher concentrations, suggesting that bacterial conversion of primary bile acids was blocked. PCB126 also disturbed bacterial metabolism of bile acids in female intestines, as revealed by higher concentrations of primary bile acids (e.g., chenodeoxycholic acid) and activation of the nuclear farnesoid X receptor signaling. In addition, PCB126 exposure impaired the metabolism of various essential vitamins (e.g., retinol, vitamin B6, and folate). Degradation of vitamin B6 by bacterial enzymes was inhibited in male intestines, resulting in its intestinal accumulation. However, PCB126 suppressed the bacterial metabolism of vitamins in female intestines, causing systematic deficiency of essential vitamins. Overall, we found that PCB126 exposure dysregulated gut microbial activities, consequently interrupting bile acid and vitamin metabolism along the gut-liver axis. The findings provided an insight of the AhR action in microbe-host metabolic communication related to PCBs.Due to the existence of some cross properties such as SHG (second-harmonic generation), ferroelectricity, piezoelectricity, and thermoelectricity, molecular ferroelectrics have been widely used as a composite multipurpose material. Particularly, organic-inorganic molecular ferroelectrics have received much interest recently because of their unique flexible structures, friendly environment, ease of synthesis, etc. Also, these hybrids show great flexibility in band-gap engineering. Here we report a new molecular halide, [C6H13N3SbBr5] n (1; C6H13N3 = 1-(3-aminopropyl)imidazole), which experiences a unique ferroelectric to paraelectric phase transition at around 230 K from space group P21 to P21/c. Significantly, compound 1 exhibits a narrow band gap with a value of 2.52 eV, large pronounced SHG-active, perfect rectangle hysteresis loops with a large spontaneous polarization of 6.86 μC/cm2. DSC (differential scanning calorimetry) and dielectric dependence on temperature tests and the volume change before and after the phase transition show that compound 1 is characterized by a second-order phase transition.