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This study contributes to the collective evaluation of SARS-CoV-2 RNA persistence and removal along the wastewater treatment stages of a treatment plant in San Antonio, Texas.

Fecal pollution of surface waters in the karst-dominated Edwards aquifer is a serious concern as contaminated waters can rapidly transmit to groundwaters, which are used for domestic purposes. Although microbial source tracking (MST) detects sources of fecal pollution, integrating data related to environmental processes (precipitation) and land management practices (septic tanks) with MST can provide better understanding of fecal contamination fluxes to implement effective mitigation strategies. Here, we investigated fecal sources and their spatial origins at recharge and contributing zones of the Edwards aquifer and identified their relationship with nutrients in different environmental/land-use conditions. During March 2019 to March 2020, water samples (

A multivariate aspect has hampered the clarification of structure-performance relationships in heterogeneous Ziegler-Natta olefin polymerization catalysis. Here, 16 catalyst samples were prepared using Mg(OEt)2 support precursors with different particle architectures. They were fingerprinted based on a series of characterization and analytical methods. In a pairwise correlation analysis, none of structural features (such as particle size and pore volume) exhibited a clear correlation with ethylene polymerization performance. However, compound features created among different structural features reasonably reproduced the ethylene polymerization activity as well as 1-hexene incorporation efficiency, where a negative influence of pores with the size below 10 nm was dictated.

Stormwater control measures such as detention basins are used to mitigate the negative effects of urban stormwater resulting from watershed development. In this study, the performance of a detention basin in mitigating nitrogen pollution was examined and the abundance of N-cycling genes (amoA, nirK, nosZ, hzsB and Ntsp-amoA) present in the soil media of the basin was measured using quantitative PCR. Results showed a net export of nitrogen from the basin, however, differences between in- and outflow concentrations were not significant. Furthermore, the quantitative PCR showed that nirK (denitrification gene) was more abundant in the winter season, whereas amoA (nitrification gene) was more abundant in the summer season. The abundance of nirK, Ntsp-amoA and hzsB genes also varied with the sampling depth of soil and based on 16S rRNA gene sequencing of soil samples, Actinobacteria and Proteobacteria were the most dominant phyla. Species diversity appeared higher in summer, while the top and bottom layer of soil clustered separately based on the bacterial community structure. These results underline the importance of understanding nitrogen dynamics and microbial processes within stormwater control measures to enhance their design and performance.

The purpose of this study was to conduct a preliminary assessment of the levels of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in wastewater at the Salitrillo Wastewater Treatment Plant in Texas during the initial peak of coronavirus disease 2019 (COVID-19) outbreak. Raw wastewater influent (24 h composite, time-based 1 L samples, n = 13) was collected weekly during June–August 2020. We measured SARS-CoV-2 RNA in wastewater by reverse transcription droplet digital PCR using the same N1 and N2 primer sets as employed in COVID-19 clinical testing. Virus RNA copies for positive samples (77%) ranged from 1.4 × 102 to 4.1 × 104 copies per liter of wastewater, and exhibited both increasing and decreasing trends, which corresponded well with the COVID-19 weekly infection rate (N1: ρ = 0.558, P = 0.048; N2: ρ = 0.487, P = 0.092). A sharp increase in virus RNA concentrations was observed during July sampling dates, consistent with the highest number of COVID-19 cases reported. This could be attributed to an increase in the spread of COVID-19 infection due to the Fourth of July holiday week gatherings (outdoor gatherings were limited to 100 people during that time). Our data show that wastewater surveillance is an effective tool to determine trends in infectious disease prevalence, and provide complementary information to clinical testing.

The short-term effects of Mn

A one-pot, four-component methodology have been developed for the synthesis of coumarin-linked triazolyl-dihydropyrimidinones (DHPM). The Biginelli reaction was combined with the click reaction for the first time in a sequential multicomponent tandem reaction approach. A series of ten such compounds have been synthesised and examined for their fluorescent properties. These were found to emit violet-blue light in the visible region of the spectrum with very high Stoke's shift values. The compounds have demonstrated high quantum yields which makes them attractive targets for their utilization as new fluorescent probes. The electronic structure of these coumarin-based donor-pi-acceptor (D-pi-A)-type organic dyes have been studied by Density Functional Theory (DFT). Thermal analysis of few of the compounds show that they are stable up to temperature range of 0-290 degrees C. The synthesised compounds have been characterised by NMR and mass spectrometry.

In this study, novel α-truxillic and β-truxinic acid-based, bio-derived diesters have been developed as internal donors for preparing Ziegler-Natta (ZN) catalysts. Impacts of these bio-derived diesters were investigated on the chemical composition, the morphology, the mode of adsorption, and the propylene polymerization performance of the catalysts in comparison to the most widely used fourth-generation catalyst containing dibutyl phthalate. The molecular structures of the diesters and the particle morphology of the catalysts were preserved in the catalyst preparation. The bio-derived diesters afforded ZN catalysts with a reasonable activity and stereospecificity in propylene polymerization along with similarly broad molecular weight distribution (MWD) as the phthalate-based catalyst. Another promising feature of the catalysts was an opposite hydrogen response in terms of expansion of MWD upon the addition of H2.

A novel approach for the stabilization of polypropylene (PP) has been proposed, which is based on the addition of a hyperbranched polymer (HBP) to reversibly trap stabilizer molecules in the dendritic interior and to prevent their volatilization. The lifetime of PP was at maximum 493% elongated by the addition of a small amount of HBP, which itself never suppressed the oxidative degradation, but effectively delayed the volatilization of stabilizers. The stabilization effect of HBP was further signified in the case of PP/SiO2 nanocomposites: HBP was grafted to SiO2 surfaces during melt mixing and was better dispersed through the nanoparticles in the matrix, providing 776% improvement in the lifetime. The versatility of the strategy was also confirmed for a variety of hindered phenols.

A library of novel 1, 2, 4-oxadiazole linked coumarin dyes have been synthesised via condensation of corresponding acid 6 and N ’-hydroxybenzimidamide 8 . This new class of organic compounds were examined for their fluorescent properties and found to emit blue light in the visible region of the spectrum with very high Stoke's shift values. Most of these compounds demonstrated high quantum yields and fluorescence life time in nano -second range which makes them quite lucrative to be used as new fluorescent probes. The highest quantum yield of 0.68 was shown by compound 9j which also shows high Stoke's shift value. The electronic structure of these coumarin-based donor–π–acceptor (D–π–A)-type organic dyes have been examined by Density Functional Theory (DFT). TGA analysis of few of the compounds show that they are stable up to temperature range of 0–245 °C. The synthesised compounds were characterised by NMR and mass spectrometry and the structure of two of these compounds have been confirmed by X-ray crystallography.

An efficient, catalyst-free, microwave-assisted approach has been developed for the synthesis of 2-aryl/alkyl-3-(1H-benzo[d]imidazol-2-yl)-2,3-dihydroquinazolin-4(1H)-one derivatives by condensing 2-aminobenzamides with various aliphatic, aromatic, and heterocyclic aldehydes. This catalyst-free approach exhibited good functional group compatibility and produced the desired products in good to excellent yields in just 10–20 min. This approach can be seen as a better alternative of the metal-catalyzed protocols used for the synthesis of this class of compounds. The formation of desired compound has also been confirmed by X-ray analysis.

An efficient, catalyst free, microwave assisted approach has been developed for the synthesis of 2-aryl/alkyl-3-(1H-benzo[d]imidazol-2-yl)-2,3-dihydroquinazolin-4(1H)-one derivatives by condensing 2-aminobenzamides with various aliphatic, aromatic and heterocyclic aldehydes. This catalyst free approach exhibited good functional group compatibility and produced the desired products in good to excellent yields in just 10-20 minutes. This approach can be seen as a better alternative of the metal catalyzed protocols used for the synthesis of this class of compounds. The formation of desired compound has also been confirmed by X-ray analysis.

The short-term effects of Mn2O3 nanoparticles (NPs) were examined for nitrifying bacterial enrichments exposed under low and high dissolved oxygen (DO) conditions using substrate (ammonia) specific oxygen uptake rates (sOUR), reverse transcriptase – quantitative polymerase chain reaction (RT-qPCR) assays, and by analysis of 16S rRNA sequences. Samples from nitrifying bioreactor were exposed in batch vessels to Mn2O3 NPs (1, 5 and 10 mg/L) for either 1 or 3 h under no additional aeration or 0.25 L/min aeration. There was increase in nitrification inhibition as determined by sOUR with increasing dosages of Mn2O3 NPs for both low and high DO. At 10 mg/L Mn2O3 NPs, the inhibition was about 7–10% for 1 and 3 h exposure in both cases. There was notable reduction in the transcript levels of amoA, hao and nirK for 10 mg/L of Mn2O3 NPs under 3 h, high DO exposure, which corresponded well with sOUR. The 16S rRNA sequencing showed that there was an inhibitory effect on ammonia oxidizers activity upon exposure to 10 mg/L of Mn2O3 NPs. Collectively, the findings in this study advanced understanding of the different effects of Mn2O3 NPs on nitrifying bacteria.

The Edwards Aquifer serves as a primary source of drinking water to more than 2 million people in south-central Texas, and as a karst aquifer, is vulnerable to human and animal fecal contamination which poses a serious risk to human and environmental health. A one-year study (Jan 2018 – Feb 2019) was conducted to determine the primary sources of fecal pollution along the Balcones and Leon Creek within the Edwards Aquifer recharge and contributing zones using general (E. coli, enterococci, and universal Bacteriodales) and host-associated (human-, dog-, cow- and chicken/duck-associated Bacteriodales) microbial source tracking (MST) assays. Additionally, sites were classified based on surrounding land use as a potential source predictor and marker levels were correlated with rain events and water quality parameters. Levels for the three general indicators were highest and exhibited similar trends across the sampling sites, suggesting that the sole use of these markers is not sufficient for specific fecal source identification. Among the host-associated markers, highest concentrations were observed for the dog marker (BacCan) in the Leon Creek area and the cow marker (BacCow) in the Balcones Creek area. Additionally, Chicken/Duck-Bac, BacCan and BacCow all exhibited higher concentrations during the spring season and the end of fall/early winter. Relatively lower concentrations were observed for the human-associated markers (HF183 and BacHum), however, levels were higher in the Leon Creek area and highest following rainfall events. Additionally, relatively higher levels in HF183 and BacHum were observed at sites having greater human population and septic tank density and may be attributed to leaks or breaks in these infrastructures. This study is the first to examine and compare fecal contamination at rural and urban areas in the recharge and contributing zones of the Edwards Aquifer using a molecular MST approach targeting Bacteroidales 16S rRNA gene-based assays. The Bacteroidales marker assays, when combined with land use and weather information, can allow for a better understanding of the sources and fluxes of fecal contamination, which can help devise effective mitigation measures to protect water quality.

In this research, Black TiO2 (BTiO2), which consisted of Rutile Based Inorganic Hollow Microspheres (RBIHM) and hydrogenated anatase TiO2 nanoparticles, decorated with MoS2 nanosheets (HBTiO2/RBIHM-MoS2 photocatalyst) was synthesized using Pulsed Laser Ablation in Liquid (PLAL) followed by microwave irradiation. Formation of vertically aligned MoS2 nanosheets, RBIHM and HBTiO2 nanoparticles were confirmed by different characterization techniques. The spectroscopic analysis revealed phase transitions in HBTiO2/RBIHM nano and microstructures along with the formation of different crystal disorders such as amorphous layers, oxygen vacancies, trivalent titanium ions and formation of molybdenum oxide (MoO3-x) in MoS2. In addition, MoS2 films in HBTiO2/RBIHM-MoS2 nanocomposite showed both Mo5+ and Mo6+ oxidation state, which was inferred that these films have a p-type conductive behavior. Furthermore, the interconnected layers of MoS2 nanosheets led to the formation of a porous like 3D nanostructure in HBTiO2/RBIHM-MoS2, which could significantly improve its photocatalytic performance. Arsenite photooxidation efficiencies of 70.3% and 96.6% and arsenate adsorption capacities of 1600 and 5200 μg g−1 were obtained for HBTiO2/RBIHM and HBTiO2/RBIHM-MoS2, respectively. The synergetic effects originated from making RBIHM-HBTiO2, RBIHM-MoS2 and MoS2–HBTiO2 heterojunctions along with the surface and morphology modification in MoS2 NSs and HBTiO2/RBIHM can explain the nanocomposite superior photocatalytic performance. The present work can trigger a broad interest in the cost-effective nanoarchitecture of visible light driven heterostructured photocatalysts.

© The Royal Society of Chemistry 2015. A novel copper(i) catalyzed, microwave-assisted one-pot, four-component sequential reaction between a propargyloxybenzaldehyde, a substituted phenyl azide, a substituted aniline and thioglycolic acid has been developed for the synthesis of 3-phenyl-2-[4-{(1-phenyl-1H-1,2,3-triazol-4-yl)methoxy}phenyl]thiazolidin-4-ones. This journal is ispartof: RSC Advances vol:5 issue:2 pages:1628-1639 status: published

In order to improve the ethylene polymerization activity and branching ability of Phillips catalysts, various bimetallic catalysts were synthesized on the basis of co-impregnation of chromium and second metal salts. The activity and branching ability of the catalysts were enhanced by the introduction of zirconium, zinc, and vanadium, while deteriorated by the introduction of molybdenum and tungsten. On the other hand, the structure of metal salt precursors did not greatly affect the catalytic performances. X-ray photoelectron spectroscopy (XPS) clarified a tendency that second metal with lower electronegativity decreased the electron density on chromium species, resulting in higher polymerization activity of the bimetallic catalysts plausibly due to enhanced ethylene activation. On the other hand, the branching ability of the catalyst improved as the catalyst activity increased due to more facile formation of α-olefin co-monomer.

A novel copper(I) catalyzed, microwave-assisted one-pot, four-component sequential reaction between a propargyloxybenzaldehyde, a substituted phenyl azide, a substituted aniline and thioglycolic acid has been developed for the synthesis of 3-phenyl-2-[4-{(1-phenyl-1H-1,2,3-triazol-4-yl)methoxy}phenyl]thiazolidin-4-ones.