Recovery of Phenanthrene-Degrading Bacteria after Simulated in Situ Persulfate Oxidation in Contaminated Soil

A continuous-flow column study was conducted to investigate the long-term effects of persulfate oxidation on the abundance and activity of the indigenous microbial community and phenanthrene-degrading bacteria in contaminated soil from a former manufactured gas plant (MGP) site. Approximately six pore volumes of a 20 g/L persulfate solution were introduced into the column, followed by simulated groundwater for 500 d. Soil samples were collected from the surface of the soil bed and along the column length immediately before and after persulfate injection and up to 500 d following injection. Exposure to persulfate led to a two- to three-log reduction in total bacterial 16S rRNA genes, severe inhibition of 14C-acetate mineralization (as a measure of general microbial activity), and a decrease in community diversity. However, relatively rapid recovery of both bacterial gene abundance and activity was observed within 30 d after persulfate exposure. Mineralization of 14C-phenanthrene was also inhibited but did not recover until 100 d post-oxidation. Known phenanthrene-degrading bacterial groups decreased to below detection limits throughout the column, with recovery times from 100 d to 500 d after persulfate injection. These findings suggest that coupling biological processes with persulfate oxidation is possible, although recovery of specific contaminant degraders may occur much later than the general microbial community recovers. Furthermore, the use of total bacterial quantity or non-specific measures of activity as a surrogate for the recovery of contaminant degraders may be inappropriate for evaluating the compatibility of chemical treatment with subsequent bioremediation

The handbook for standardized field and laboratory measurements in terrestrial climate change experiments and observational studies (ClimEx)

1. Climate change is a world‐wide threat to biodiversity and ecosystem structure, functioning and services. To understand the underlying drivers and mechanisms, and to predict the consequences for nature and people, we urgently need better understanding of the direction and magnitude of climate change impacts across the soil–plant–atmosphere continuum. An increasing number of climate change studies are creating new opportunities for meaningful and high‐quality generalizations and improved process understanding. However, significant challenges exist related to data availability and/or compatibility across studies, compromising opportunities for data re‐use, synthesis and upscaling. Many of these challenges relate to a lack of an established ‘best practice’ for measuring key impacts and responses. This restrains our current understanding of complex processes and mechanisms in terrestrial ecosystems related to climate change. 2. To overcome these challenges, we collected best‐practice methods emerging from major ecological research networks and experiments, as synthesized by 115 experts from across a wide range of scientific disciplines. Our handbook contains guidance on the selection of response variables for different purposes, protocols for standardized measurements of 66 such response variables and advice on data management. Specifically, we recommend a minimum subset of variables that should be collected in all climate change studies to allow data re‐use and synthesis, and give guidance on additional variables critical for different types of synthesis and upscaling. The goal of this community effort is to facilitate awareness of the importance and broader application of standardized methods to promote data re‐use, availability, compatibility and transparency. We envision improved research practices that will increase returns on investments in individual research projects, facilitate second‐order research outputs and create opportunities for collaboration across scientific communities. Ultimately, this should significantly improve the quality and impact of the science, which is required to fulfil society's needs in a changing world

Remediation of Contaminated Soil from a former Manufactured Gas Plant with Heat-Activated Sodium Persulfate

Contaminated wastes from Manufactured Gas Plants (MGP's) are a widespread problem in the United States, and the surrounding soils are most likely contaminated with Polycyclic Aromatic Hydrocarbons (PAH's), some of which are known or suspected carcinogens. Soil from a former MGP site in Salisbiuy, NC, was studied in batch and column chemical oxidation experiments. Sodium persulfate was selected as the oxidant of interest due to its complex radical formation chemistry, yet relatively long persistence in the subsurface. Heat activation of the oxidant was chosen because of its documented effectiveness at remediating a variety of chemical contaminants. The depletion of oxidant in the subsurface is a function of the initial concentration, and therefore its relative concentration with respect to the soil. The maximum soil oxidant anion demand was 8.88 ± 0.70grams oxidant consumed per kg of soil, which occurred at 7 days, 40°C, and 40 g/kg sodium persulfate to soil. The total batch oxidant demand at 20 days was 31.52 ± 0.12 grams oxidant consumed per kg of soil at 40°C and 40 g/kg sodium persulfate to soil. The maximum PAH degradation in batch experiments were 44 ± 33% at 40°C and 55 ± 5% at 20°C. Because of the high fraction of non-extractable organic material in MGP soils, which can contain sorbed PAH's, the concentration of PAH's available to the per sulfate may only be a small fraction of the total concentration in a given soil. The total organic carbon must be taken into account in both batch and column experiments. Column experiments were conducted using a 50/50 dry weight ratio of Salisbury MGP soil and Accusand 40-50 quartz sand. Three to four ring PAH's were the most abundant and degraded of the group, yet some PAH's were pushed out of small column experiments in colloidal and fine particulate matter that had been oxidized. In a stainless steel column of 100-cm length and 10.2-cm diameter, PAH's were oxidized using 20 g/L sodium persulfate for 5.29 pore volumes at 40°C, and the vertical degradation profile was examined. The Influent, Port A, B, and C degradation percentages were 42 ± 33%, 19 ± 4.3%, 31 ± 4.0%, and 5.6 ± 0.9%, respectively. In order to model such experiments, further investigation is needed on reaction rates of sodium persulfate with contaminants of concern.Master of Science in Environmental Engineerin

Recovery of Phenanthrene-Degrading Bacteria after Simulated in Situ Persulfate Oxidation in Contaminated Soil

A continuous-flow column study was conducted to investigate the long-term effects of persulfate oxidation on the abundance and activity of the indigenous microbial community and phenanthrene-degrading bacteria in contaminated soil from a former manufactured gas plant (MGP) site. Approximately six pore volumes of a 20 g/L persulfate solution were introduced into the column, followed by simulated groundwater for 500 d. Soil samples were collected from the surface of the soil bed and along the column length immediately before and after persulfate injection and up to 500 d following injection. Exposure to persulfate led to a two- to three-log reduction in total bacterial 16S rRNA genes, severe inhibition of (14)C-acetate mineralization (as a measure of general microbial activity), and a decrease in community diversity. However, relatively rapid recovery of both bacterial gene abundance and activity was observed within 30 d after persulfate exposure. Mineralization of (14)C-phenanthrene was also inhibited but did not recover until 100 d post-oxidation. Known phenanthrene-degrading bacterial groups decreased to below detection limits throughout the column, with recovery times from 100 d to 500 d after persulfate injection. These findings suggest that coupling biological processes with persulfate oxidation is possible, although recovery of specific contaminant degraders may occur much later than the general microbial community recovers. Furthermore, the use of total bacterial quantity or non-specific measures of activity as a surrogate for the recovery of contaminant degraders may be inappropriate for evaluating the compatibility of chemical treatment with subsequent bioremediation

Be Yourself: Authenticity as a Long-Term Mating Strategy

We hypothesize that “being yourself” is the dating strategy of individuals that have successful long-term relationships. Study 1 examined the relationships between authenticity and personality variables that predict relationship outcome. Study 2 employed a two-part acts nomination design to enumerate “being yourself” while dating and to examine personality correlates of “being yourself”. Study 3 explored whether individuals being themselves are attractive and if being yourself results in assortative mating with authentic individuals. Study 4 determined the effect of “be yourself” mindset priming on “be yourself” dating behavior. Study 1 found that authenticity is associated with emotional intelligence and positive relational outcomes. Study 2 found that “being yourself” dating behavior is associated with authenticity, secure attachment, and low narcissism. Study 3 found that “be yourself” dating behavior is attractive and facilitates assortative mating with authentic individuals. Study 4 found that rejection sensitive individuals are more likely to engage in “be yourself” dating behavior when made to feel safe to be themselves. “Be yourself” is the dating strategy that authentic individuals use to facilitate successful long-term relationships

Gene therapy for neurological disorders: progress and prospects

Adeno-associated viral (AAV) vectors are a rapidly emerging gene therapy platform for the treatment of neurological diseases. In preclinical studies, transgenes encoding therapeutic proteins, microRNAs, antibodies or gene-editing machinery have been successfully delivered to the central nervous system with natural or engineered viral capsids via various routes of administration. Importantly, initial clinical studies have demonstrated encouraging safety and efficacy in diseases such as Parkinson disease and spinal muscular atrophy, as well as durability of transgene expression. Here, we discuss key considerations and challenges in the future design and development of therapeutic AAV vectors, highlighting the most promising targets and recent clinical advances