Evaluation of strategies to minimize ecotoxic side-effects of sorbent-based sediment remediation.
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ABSTRACT:
SUBMITTER: Han Z
PROVIDER: S-EPMC5516141 | biostudies-other | 2017 Aug
REPOSITORIES: biostudies-other
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Project description:Thin-layer capping using activated carbon has been described as a cost-effective in situ sediment remediation method for organic contaminants. We compared the capping efficiency of powdered activated carbon (PAC) against granular activated carbon (GAC) using contaminated sediment from Oskarshamn harbor, Sweden. The effects of resuspension on contaminant retention and cap integrity were also studied. Intact sediment cores were collected from the outer harbor and brought to the laboratory. Three thin-layer caps, consisting of PAC or GAC mixed with clay or clay only, were added to the sediment surface. Resuspension was created using a motor-driven paddle to simulate propeller wash from ship traffic. Passive samplers were placed in the sediment and in the water column to measure the sediment-to-water release of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and metals. Our results show that a thin-layer cap with PAC reduced sediment-to-water fluxes of PCBs by 57% under static conditions and 91% under resuspension. Thin-layer capping with GAC was less effective than PAC but reduced fluxes of high-molecular weight PAHs. Thin-layer capping with activated carbon was less effective at retaining metals, except for Cd, the release of which was significantly reduced by PAC. Resuspension generally decreased water concentrations of dissolved cationic metals, perhaps because of sorption to suspended sediment particles. Sediment resuspension in treatments without capping increased fluxes of PCBs with log octanol-water partitioning coefficient (KOW ) > 7 and PAHs with log KOW of 5-6, but resuspension reduced PCB and PAH fluxes through the PAC thin-layer cap. Overall, PAC performed better than GAC, but adverse effects on the benthic community and transport of PAC to nontarget areas are drawbacks that favor the use of GAC. Environ Toxicol Chem 2022;41:1096-1110. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
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Project description:This study tested two sediment amendments with active sorbents: injection of aluminum (Al) into sediments and thin-layer capping with Polonite (calcium-silicate), with and without the addition of activated carbon (AC), for their simultaneous sequestration of sediment phosphorus (P), hydrophobic organic contaminants (HOCs), and metals. Sediment cores were collected from a eutrophic and polluted brackish water bay in Sweden and incubated in the laboratory to measure sediment-to-water contaminant release and effects on biogeochemical processes. We used diffusive gradients in thin-film passive samplers for metals and semi-permeable membrane devices for the HOC polychlorinated biphenyls and polycyclic aromatic hydrocarbons. Al injection into anoxic sediments completely stopped the release of P and reduced the release of cadmium (Cd, -97%) and zinc (Zn, -95%) but increased the sediment fluxes of PAH (+49%), compared to the untreated sediment. Polonite mixed with AC reduced the release of P (-70%), Cd (-67%), and Zn (-89%) but increased methane (CH4) release. Adding AC to the Al or Polonite reduced the release of HOCs by 40% in both treatments. These results not only demonstrate the potential of innovative remediation techniques using composite sorbent amendments but also highlight the need to assess possible ecological side effects on, for example, sedimentary microbial processes.
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Project description:The global decline of mutualists such as pollinators and seed dispersers may cause negative direct and indirect impacts on biodiversity. Mutualistic network models used to understand the stability of mutualistic systems indicate that species with low partner diversity are most vulnerable to coextinction following mutualism disruption. However, existing models have not considered how species vary in their dependence on mutualistic interactions for reproduction or survival, overlooking the potential influence of this variation on species' coextinction vulnerability and on network stability. Using global databases and field experiments focused on the seed dispersal mutualism, we found that plants and animals that depend heavily on mutualistic interactions have higher partner diversity. Under simulated network disruption, this empirical relationship strongly reduced coextinction because the species most likely to lose mutualists depend least on their mutualists. The pattern also reduced the importance of network structure for stability; nested network structure had little effect on coextinction after simulations incorporated the empirically derived relationship between partner diversity and mutualistic dependence. Our results highlight a previously unknown source of stability in mutualistic networks and suggest that differences among species in their mutualistic strategy, rather than network structure, primarily accounts for stability in mutualistic communities.
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Project description:Although awareness of side effects over the course of psychotherapy is growing, side effects are still not always reported. The purpose of the present study was to examine side effects in a randomized controlled trial comparing Metacognitive Training for Depression (D-MCT) and a cognitive remediation training in patients with depression. 84 patients were randomized to receive either D-MCT or cognitive remediation training (MyBrainTraining) for 8 weeks. Side effects were assessed after the completion of each intervention (post) using the Short Inventory of the Assessment of Negative Effects (SIAN) and again 6 months later (follow-up) using the Negative Effects Questionnaire (NEQ). D-MCT and MyBrainTraining did not differ significantly in the number of side effects. At post assessment, 50% of the D-MCT group and 59% of the MyBrainTraining group reported at least one side effect in the SIAN. The most frequently reported side effect was disappointment in subjective benefit of study treatment. At follow-up, 52% reported at least one side effect related to MyBrainTraining, while 34% reported at least one side effect related to the D-MCT in the NEQ. The most frequently reported side effects fell into the categories of "symptoms" and "quality". Our NEQ version was missing one item due to a technical error. Also, allegiance effects should be considered. The sample size resulted in low statistical power. The relatively tolerable number of side effects suggests D-MCT and MyBrainTraining are safe and well-received treatment options for people with depression. Future studies should also measure negative effects to corroborate our results.
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Project description:Sediment microbial fuel cells (SMFCs) generate electricity through the oxidation of reduced compounds, such as sulfide or organic carbon compounds, buried in anoxic sediments. The ability to remove sulfide suggests their use in the remediation of sediments impacted by point source organic matter loading, such as occurs beneath open pen aquaculture farms. However, for SMFCs to be a viable technology they must remove sulfide at a scale relevant to the environmental contamination and their impact on the sediment geochemistry as a whole must be evaluated. Here we address these issues through a laboratory microcosm experiment. Two SMFCs placed in high organic matter sediments were operated for 96 days and compared to open circuit and sediment only controls. The impact on sediment geochemistry was evaluated with microsensor profiling for oxygen, sulfide, and pH. The SMFCs had no discernable effect on oxygen profiles, however porewater sulfide was significantly lower in the sediment microcosms with functioning SMFCs than those without. Depth integrated sulfide inventories in the SMFCs were only 20% that of the controls. However, the SMFCs also lowered pH in the sediments and the consequences of this acidification on sediment geochemistry should be considered if developing SMFCs for remediation. The data presented here indicate that SMFCs have potential for the remediation of sulfidic sediments around aquaculture operations.
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Project description:Phase separation is a physiological process occurring spontaneously when single-phase molecular complexes separate in two phases, a concentrated phase and a more diluted one. Eukaryotic cells employ phase transition strategies to promote the formation of intracellular territories not delimited by membranes with increased local RNA concentration, such as nucleolus, paraspeckles, P granules, Cajal bodies, P-bodies, and stress granules. These organelles contain both proteins and coding and non-coding RNAs and play important roles in different steps of the regulation of gene expression and in cellular signaling. Recently, it has been shown that most human RNA-binding proteins (RBPs) contain at least one low-complexity domain, called prion-like domain (PrLD), because proteins harboring them display aggregation properties like prion proteins. PrLDs support RBP function and contribute to liquid-liquid phase transitions that drive ribonucleoprotein granule assembly, but also render RBPs prone to misfolding by promoting the formation of pathological aggregates that lead to toxicity in specific cell types. Protein-protein and protein-RNA interactions within the separated phase can enhance the transition of RBPs into solid aberrant aggregates, thus causing diseases. In this review, we highlight the role of phase transition in human disease such as amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and in cancer. Moreover, we discuss novel therapeutic strategies focused to control phase transitions by preventing the conversion into aberrant aggregates. In this regard, the stimulation of chaperone machinery to disassemble membrane-less organelles, the induction of pathways that could inhibit aberrant phase separation, and the development of antisense oligonucleotides (ASOs) to knockdown RNAs could be evaluated as novel therapeutic strategies for the treatment of those human diseases characterized by aberrant phase transition aggregates.
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Project description:BACKGROUND:People seek information on the Web for managing their colorectal cancer (CRC) risk but retrieve much personally irrelevant material. Targeting information pertinent to this cohort via a frequently asked question (FAQ) format could improve outcomes. OBJECTIVE:We identified and prioritized colorectal cancer information for men and women aged 35 to 74 years (study 1) and built a website containing FAQs ordered by age and gender. In study 2, we conducted a randomized controlled trial (RCT) to test whether targeted FAQs were more influential on intention to act on CRC risk than the same information accessed via a generic topic list. Secondary analyses compared preference for information delivery, usability, relevance, and likelihood of recommendation of FAQ and LIST websites. METHODS:Study 1 determined the colorectal cancer information needs of Australians (N=600) by sex and age group (35-49, 50-59, 60-74) through a Web-based survey. Free-text responses were categorized as FAQs: the top 5 issues within each of the 6 cohorts were identified. Study 2 (N=240) compared the impact of presentation as targeted FAQ links to information with links presented as a generic list (LIST) and a CONTROL (no information) condition. We also tested preference for presentation of access to information as FAQ or LIST by adding a CHOICE condition (a self-selected choice of FAQs or a list of information topics). RESULTS:Study 1 showed considerable consistency in information priorities among all 6 cohorts with 2 main concerns: treatment of CRC and risk factors. Some differences included a focus on general risk factors, excluding diet and lifestyle, in the younger cohort, and on the existence of a test for CRC in the older cohorts. Study 2 demonstrated that, although respondents preferred information access ordered by FAQs over a list, presentation in this format had limited impact on readiness to act on colorectal cancer risk compared with the list or a no-information control (P=.06). Both FAQ and LIST were evaluated as equally usable. Those aged 35 to 49 years rated the information less relevant to them and others in their age group, and information ordered by FAQs was rated, across all age groups and both sexes, as less relevant to people outside the age group targeted within the FAQs. CONCLUSIONS:FAQs are preferred over a list as a strategy for presenting access to information about CRC. They may improve intention to act on risk, although further research is required. Future research should aim to identify better the characteristics of information content and presentation that optimize perceived relevance and fully engage the target audience. TRIAL REGISTRATION:Australian New Zealand Clinical Trials Registry: ACTRN12618000137291; https://www.anzctr.org. au/Trial/Registration/TrialReview.aspx?id=374129 (Archived by WebCite at http://www.webcitation.org/6x2Mr6rPC).
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Project description:BACKGROUND: A comprehensive evaluation and remediation program is an essential component of any residency program. The evaluation system should identify problems accurately and early and allow residents with problems to be assigned to a remediation program that effectively deals with them. Elements of a proactive remediation program include a process for outlining deficiencies, providing resources for improvement, communicating clear goals for acceptable performance, and reevaluating performance against these goals. INTERVENTION: In recognition of the importance of early detection and prompt remediation of the struggling resident, we sought to develop a multifaceted approach to resident evaluation with the aim of early identification and prompt remediation of difficulties. This article describes our comprehensive evaluation program and remediation program, which uses resources within our radiology department and institutional graduate medical education office. DISCUSSION: An effective evaluation system should identify problems accurately and early, whereas a proactive remediation program should effectively deal with issues once they are identified.
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