The H-02 wetland was constructed to treat building process water and storm runoff water from the Tritium Processing Facility on the Department of Energy's Savannah River Site (Aiken, SC). Monthly ...monitoring of copper (Cu) and zinc (Zn) concentrations and water quality parameters in surface waters continued from 2014 to 2016. Metal speciation was modeled at each sampling occasion. Total Cu and Zn concentrations released to the effluent stream were below the NPDES limit, and the average removal efficiency was 65.9% for Cu and 71.1% for Zn. The metal-removal processes were found out to be seasonally regulated by sulfur cycling indicated by laboratory and model results. High temperature, adequate labile organic matter, and anaerobic conditions during the warm months (February to August) favored sulfate reduction that produced sulfide minerals to significantly remove metals. However, the dominant reaction in sulfur cycling shifted to sulfide oxidation during the cool months (September to next March). High concentrations of metal-organic complexes were observed, especially colloidal complexes of metal and fulvic acid (FA), demonstrating adsorption to organic matter became the primary process for metal removal. Meanwhile, the accumulation of metal-FA complexes in the wetland system will cause negative effects to the surrounding environment as they are biologically reactive, highly bioavailable, and can be easily taken up and transferred to ecosystems by trophic exchange.
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•The metal removal process in the H-02 constructed wetland was season-related and regulated by sulfur dynamics.•Metals were removed with sulfide precipitation (warm months) and by adsorption to organic matter (cool months).•Metal bioavailability increased in cool months because concentrations of colloidal metal-fulvic acid complexes increased.•The H-02 constructed wetlands increased metal bioavailability and may cause negative effects to the surrounding ecosystems.
Excessive noise is becoming a significant problem for intensive care units (ICUs). This paper first reviews the impact of noise on patients' sleep in ICUs. Five previous studies have demonstrated ...such impacts, whereas six other studies have shown other factors to be more important. Staff conversation and alarms are generally regarded as the most disturbing noises for patients' sleep in ICUs. Most research in this area has focused purely on noise level, but work has been very limited on the relationships between sleep quality and other acoustic parameters, including spectrum and reverberation time. Sound-absorbing treatment is a relatively effective noise reduction strategy, whereas sound masking appears to be the most effective technique for improving sleep. For future research, there should be close collaboration between medical researchers and acousticians.
Sleep disturbances are common in critically ill patients and when sleep does occur it traverses the day-night periods. The reduction in plasma melatonin levels and loss of circadian rhythm observed ...in critically ill patients receiving mechanical ventilation may contribute to this irregular sleep-wake pattern. We sought to evaluate the effect of exogenous melatonin on nocturnal sleep quantity in these patients and, furthermore, to describe the kinetics of melatonin after oral administration in this patient population, thereby guiding future dosing schedules.
We conducted a randomised double-blind placebo-controlled trial in 24 patients who had undergone a tracheostomy to aid weaning from mechanical ventilation. Oral melatonin 10 mg or placebo was administered at 9 p.m. for four nights. Nocturnal sleep was monitored using the bispectral index (BIS) and was expressed in terms of sleep efficiency index (SEI) and area under the curve (AUC). Secondary endpoints were SEI measured by actigraphy and nurse and patient assessments. Plasma melatonin concentrations were measured in nine patients in the melatonin group on the first night.
Nocturnal sleep time was 2.5 hours in the placebo group (mean SEI = 0.26, 95% confidence interval CI 0.17 to 0.36). Melatonin use was associated with a 1-hour increase in nocturnal sleep (SEI difference = 0.12, 95% CI -0.02 to 0.27; P = 0.09) and a decrease in BIS AUC indicating 'better' sleep (AUC difference = -54.23, 95% CI -104.47 to -3.98; P = 0.04). Results from the additional sleep measurement methods were inconclusive. Melatonin appeared to be rapidly absorbed from the oral solution, producing higher plasma concentrations relative to similar doses reported in healthy individuals. Plasma concentrations declined biexponentially, but morning (8 a.m.) plasma levels remained supraphysiological.
In our patients, nocturnal sleep quantity was severely compromised and melatonin use was associated with increased nocturnal sleep efficiency. Although these promising findings need to be confirmed by a larger randomised clinical trial, they do suggest a possible future role for melatonin in the routine care of critically ill patients. Our pharmacokinetic analysis suggests that the 10-mg dose used in this study is too high in these patients and may lead to carryover of effects into the next morning. Reduced doses of 1 to 2 mg could be used in future studies.
Current Controlled Trials ISRCTN47578325.
At the beginning of each class, we attest to the virtues of writing with clarity, focus, and authority, yet we saddle students with a syllabus that lacks all these virtues. Added, our students are ...forced to reference it routinely throughout the semester to navigate the course. Admittedly, I myself perpetuate this type of course design. My 2022 resolution is to get my syllabus in order. Document design is a good place to start. If we follow Banwarshi’s guidance, we can start our collection and study of genres by placing our students at the center of each of the nested genres within the syllabus. What if the course requirements (project submission minimums, assignment deadlines, and the usual “thou shalts”) looked like real-world contracts students would have to acknowledge, sign, and abide? What if the assignment descriptions looked more like an informational brochure, tri-fold, tour guide, or prix fixe menu? What if our contact information was a digital business card with a link to provide an efficient path to our office? We could continue with our “what if’s” concerning the schedule of assignments, required texts, and all the remaining nested eggs in our syllabi. Importantly, would the resulting consequences help our students? I think so.
Water, sediment, and biota from two streams on the Savannah River Site were sampled to study mercury (Hg) biogeochemistry. Total and methyl- Hg (MHg) concentrations were measured for all samples, ...speciation models were used to explore Hg speciation in the water, and Diffusive gradients in thin films (DGT) were applied to indicate the vertical profiles of labile Hg (DGT-Hg). Trophic position (δ15N) was estimated for biota and used to establish MHg biomagnification model. The speciation model indicated Hg methylation in the water occurred on settling particles and the most bioavailable Hg species to bacteria were complexes of inorganic Hg and labile organic ligands. Correspondingly, dissolved organic carbon concentrations were positively related to MHg concentrations in the water. In the sediment, the sharp increase of DGT-Hg around the sediment water interface underscores the importance of this interface, which determines the differences in the accumulation and generation of labile Hg among different waterbodies. The positive correlation between sediment MHg and sulfate concentrations suggested possible methylation reaction by dissimilatory sulfate reducing bacteria in the sediment. The food web magnification factors of MHg were 9.6 (95% CI: 4.0–23.4) and 4.4 (95% CI: 2.5–7.7) for the two streams established with trophic data of biofilm, invertebrates, and fish. Meanwhile, DGT-Hg concentrations in the water were positively correlated to biofilm Hg concentrations, which can be combined with the MHg biomagnification model to generate a modified biomagnification model that estimate MHg bioaccumulation with only labile Hg concentrations in the water. With this approach, Hg accumulation in abiotic and biotic environmental compartments was connected and the different bioaccumulation patterns of Hg in different waterbodies were explained with both geochemical and biological factors.
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•Mercury (Hg) methylation in the water occurred on settling particles.•Complexes of Hg(II) and labile organic ligands were most bioavailable to SRB.•Labile and bioavailable Hg was mostly generated in the sediment water interface (SWI).•The SWI determines the differences in Hg accumulation among different waterbodies.•Concentrations of biofilm-Hg and DGT-Hg in the water were positively correlated.
We conducted an exposure experiment with Diffusive Gradients in Thin- Films (DGT), fathead minnow (Pimephales promelas), and yellow lampmussel (Lampsilis cariosa) to estimate bioavailability and ...bioaccumulation of Cu. We hypothesized that Cu concentrations measured by DGT can be used to predict Cu accumulation in aquatic animals and alterations of water chemistry can affect DGT's predict ability. Three water chemistries (control soft water, hard water, and addition of natural organic matter (NOM)) and three Cu concentrations (0, 30, and 60 μg/L) were selected, so nine Cu-water chemistry combinations were used. NOM addition treatments resulted in decreased concentrations of DGT-measured Cu and free Cu ion predicted by Biotic Ligand Model (BLM). Both hard water and NOM addition treatments had reduced concentrations of Cu ion and Cu-dissolved organic matter complexes compared to other treatments. DGT-measured Cu concentrations were linearly correlated to fish accumulated Cu, but not to mussel accumulated Cu. Concentrations of bioavailable Cu predicted by BLM, the species complexed with biotic ligands of aquatic organisms and, was highly correlated to DGT-measured Cu. In general, DGT-measured Cu fit Cu accumulations in fish, and this passive sampling technique is acceptable at predicting Cu concentrations in fish in waters with low NOM concentrations.
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•Addition of natural organic matter (NOM) resulted in decreased concentrations of DGT-measured Cu.•DGT-measured Cu included free Cu ion, inorganic Cu, and Cu-dissolved organic matter (DOM) complexes.•Elevated water hardness decreased concentrations of free Cu and Cu- DOM complexes in the water.•DGT can well predict Cu accumulation in fathead minnows, but not in yellow lampmussels.•DGT is acceptable at predicting Cu accumulations in the fish, especially with low NOM concentrations in the water.
Water chemistry is able to influence DGT's ability in predicting Cu accumulation by aquatic animals, since NOM addition and elevated water hardness can reduce concentrations of free Cu ion, Cu-dissolved organic matter complexes, and/or inorganic Cu in the water.
True morels (Morchella, Ascomycota) are arguably the most highly-prized of the estimated 1.5 million fungi that inhabit our planet. Field guides treat these epicurean macrofungi as belonging to a few ...species with cosmopolitan distributions, but this hypothesis has not been tested. Prompted by the results of a growing number of molecular studies, which have shown many microbes exhibit strong biogeographic structure and cryptic speciation, we constructed a 4-gene dataset for 177 members of the Morchellaceae to elucidate their origin, evolutionary diversification and historical biogeography. Diversification time estimates place the origin of the Morchellaceae in the middle Triassic 243.63 (95% highest posterior density HPD interval: 169.35–319.89) million years ago (Mya) and the divergence of Morchella from its closest relatives in the early Cretaceous 129.61 (95% HPD interval: 90.26–173.16) Mya, both within western North America. Phylogenetic analyses identified three lineages within Morchella: a basal monotypic lineage represented by Morchella rufobrunnea, and two sister clades comprising the black morels (Elata Clade, 26 species) and yellow morels (Esculenta Clade, 16 species). Morchella possesses a Laurasian distribution with 37/41 species restricted to the Holarctic. All 33 Holarctic species represented by multiple collections exhibited continental endemism. Moreover, 16/18 North American and 13/15 Eurasian species appeared to exhibit provincialism. Although morel fruit bodies produce thousands of explosively discharged spores that are well suited to aerial dispersal, our results suggest that they are poorly adapted at invading novel niches. Morels also appear to have retained the ancestral fruit body plan, which has remained remarkably static since the Cretaceous.
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