The photoreactivity of treated wastewater effluent organic matter differs from that of natural organic matter, and the indirect phototransformation rates of micropollutants originating in wastewater ...are expected to depend on the fractional contribution of wastewater to total stream flow. Photodegradation rates of four common compounds of wastewater origin (sulfamethoxazole, sulfadimethoxine, cimetidine and caffeine) were measured in river water, treated municipal wastewater effluent and mixtures of both to simulate various effluent-stream water mixing conditions that could occur in environmental systems. Compounds were chosen for their unique photodegradation pathways with the photochemically produced reactive intermediates, triplet-state excited organic matter (3OM*), singlet oxygen (1O2), and hydroxyl radicals (OH). For all compounds, higher rates of photodegradation were observed in effluent relative to upstream river water. Sulfamethoxazole degraded primarily via direct photolysis, with some contribution from OH and possibly from carbonate radicals and other unidentified reactive intermediates in effluent-containing samples. Sulfadimethoxine also degraded mainly by direct photolysis, and natural organic matter appeared to inhibit this process to a greater extent than predicted by light screening. In the presence of effluent organic matter, sulfadimethoxine showed additional reactions with OH and 1O2. In all water samples, cimetidine degraded by reaction with 1O2 (>95%) and caffeine by reaction with OH (>95%). In river water mixtures, photodegradation rate constants for all compounds increased with increasing fractions of effluent. A conservative mixing model was able to predict reaction rate constants in the case of hydroxyl radical reactions, but it overestimated rate constants in the case of 3OM* and 1O2 pathways. Finally, compound degradation rate constants normalized to the rate of light absorption by water correlated with E2/E3 ratios (sample absorbance at 254 nm divided by sample absorbance at 365 nm), suggesting that organic matter optical properties may hold promise to predict indirect compound photodegradation rates for various effluent mixing ratios.
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•Sulfamethoxazole, sulfadimethoxine, cimetidine and caffeine photodegradation rates were greater in effluent than river water.•Compound photodegradation rates increased with increasing fraction of effluent in river water.•Compound photodegradation reactions via 3OM* or 1O2 pathways were quenched by river water organic matter.•Indirect photodegradation rate constants correlated with water optical properties (E2/E3).
Bone defects are a common clinical issue, but therapeutic efficiency can be challenging in cases of more considerable traumas or elderly patients with degenerated physiological metabolism. To address ...this issue, a more suitable cell‐biomaterial construct promoting bone regeneration has been extensively investigated, with the chitosan scaffold being considered a potential candidate. In this study, chitosan was crosslinked with different doses of glucose (CTS‐10~50%Glc) using a modified Maillard reaction condition to develop a more appropriate cell‐biomaterial construct. Mouse MC3T3‐E1 pre‐osteoblasts were seeded onto the scaffolds to examine their osteoinductive capability. The results showed that CTS‐Glc scaffolds with higher glucose contents effectively improved the adhesion and survival of mouse MC3T3‐E1 pre‐osteoblasts and promoted their differentiation and mineralization. It was further demonstrated that the membrane integrin α5 subunit of pre‐osteoblasts is the primary adhesion molecule that communicates with CTS‐Glc scaffolds. After that, Akt signaling was activated, and then bone morphogenetic protein 4 was secreted to initiate the osteoinduction of pre‐osteoblasts. The prepared CTS‐Glc scaffold, with enhanced osteoinduction capability and detailed mechanism elucidations, offers a promising candidate material for advancing bone tissue engineering and clinical regenerative medicine. As a result, this study presents a potential tool for future clinical treatment of bone defects.
Dissolved organic matter (DOM) originating from the extensive Arctic tundra is an important source of organic material to the Arctic Ocean. Chemical characteristics of whole water dissolved organic ...matter (DOM) and the fulvic acid fraction of DOM were studied from nine surface waters in the Arctic region of Alaska to gain insight into the extent of microbial and photochemical transformation of this DOM. All the fulvic acids had a strong terrestrial/higher plant signature, with uniformly depleted δ13C values of −28‰, and low fluorescence indices around 1.3. Several of the measured chemical characteristics of the Arctic fulvic acids were related to water residence time, a measure of environmental exposure to sunlight and microbial activity. For example, fulvic acids from Arctic streams had higher aromatic contents, higher specific absorbance values, lower nitrogen content, lower amino acid–like fluorescence and were more depleted in δ15N relative to fulvic acids isolated from lake and coastal surface waters. The differences in the nitrogen signature between the lake and coastal fulvic acids compared to the stream fulvic acids indicated that microbial contributions to the fulvic acid pool increased with increasing water residence time. The photo‐lability of the fulvic acids was positively correlated with water residence time, suggesting that the fulvic acids isolated from source waters with larger water residence times (i.e., lakes and coastal waters) have experienced greater photochemical degradation than the stream fulvic acids. In addition, many of the initial differences in fulvic acid chemical characteristics across the gradient of water residence times were consistent with changes observed in fulvic acid photolysis experiments. Taken together, results from this study suggest that photochemical processes predominantly control the chemical character of fulvic acids in Arctic surface waters. Our findings show that hydrologic transport in addition to biogeochemical alteration of the organic matter must be considered in order to predict the ultimate fate of Arctic DOM.
Aim
This study was designed to investigate the feasibility, acceptability, and preliminary efficacy of a nurse‐led communication intervention among surrogates in the intensive care unit (ICU) guided ...by the COMFORT (Connect; Options; Making meaning; Family caregivers; Openings; Relating; Team) communication model.
Background
As frontline communicators, nurses experience communication difficulties with surrogates who face complex informational and emotional barriers when making decisions for critically ill patients in the ICU. However, research on effective nurse communication focusing on both curative and end‐of‐life (EOL) care is lacking in the literature.
Design
A single‐centre two‐group pretest‐posttest quasi‐experiment.
Method
The total sample included 41 surrogates of adult ventilated patients. Twenty participants were allocated to the intervention group who received a daily 20‐min telephone call with content based on the COMFORT communication model. Twenty‐one participants comprised the control group who received usual care. Participants completed a questionnaire before and after the study measuring satisfaction, anxiety and depression, decisional conflict, and quality of communication. The Transparent Reporting of Evaluations with Nonrandomized Designs (TREND) checklist was followed for nonrandomised controlled trials.
Result
The intervention was feasible, with 19 of 20 surrogates completing the follow‐up surveys, and 48 telephone conversations completed (48% of the planned phone calls). Surrogates' satisfaction was higher in the intervention group than in the control group after adjusting for the selected covariates (25.43 and 24.15, respectively; p = .512). Preliminary efficacy outcomes favouring the intervention included quality of communication with healthcare providers, but not surrogates' perceived depression/anxiety and decisional conflicts.
Conclusion
Implementation of the intervention is feasible, acceptable, and favourable among surrogates to improve quality of communication with healthcare providers in the ICU. Further research is needed to determine whether the intervention could be implemented by nurses to improve surrogates' outcomes in other ICUs.
The ice‐cover period in lakes is increasingly recognized for its distinct combination of physical and biological phenomena and ecological relevance. Knowledge gaps exist where research areas of ...hydrodynamics, biogeochemistry and biology intersect. For example, density‐driven circulation under ice coincides with an expansion of the anoxic zone, but abiotic and biotic controls on oxygen depletion have not been disentangled, and while heterotrophic microorganisms and migrating phytoplankton often thrive at the oxycline, the extent to which physical processes induce fluxes of heat and substrates that support under‐ice food webs is uncertain. Similarly, increased irradiance in spring can promote growth of motile phytoplankton or, if radiatively driven convection occurs, more nutritious diatoms, but links between functional trait selection, trophic transfer to zooplankton and fish, and the prevalence of microbial versus classical food webs in seasonally ice‐covered lakes remain unclear. Under‐ice processes cascade into and from the ice‐free season, and are relevant to annual cycling of energy and carbon through aquatic food webs. Understanding the coupling between state transitions and the reorganization of trophic hierarchies is essential for predicting complex ecosystem responses to climate change. In this interdisciplinary review we describe existing knowledge of physical processes in lakes in winter and the parallel developments in under‐ice biogeochemistry and ecology. We then illustrate interactions between these processes, identify extant knowledge gaps and present (novel) methods to address outstanding questions.
Plain Language Summary
Winter is an important but poorly understood period for lake ecosystems at high latitudes. Incoming solar radiation is diminished by ice and (often) snow, flows of oxygen and substrates such as organic matter or nutrients from outside the lake are limited, and wind no longer causes turbulent mixing of the water column. The sediments become a source of heat as well as of solutes which drive denser water toward the bottom. The resulting density stratification creates a template for the development of winter ecosystems. Distinct oxygenated and oxygen‐depleted zones will affect microbial community structure and the habitat and behavior of zooplankton and fish. Conditions can rapidly change in spring with increased irradiance and incoming snowmelt. This paper reviews how physical, biogeochemical and biological processes act together to shape aquatic ecosystems in winter and in spring. In addition, we present an overview of the unknowns regarding the interactions between the different processes, which can now be posed due to improved understanding of under‐ice hydrodynamics and the nature of lake ice, of biogeochemistry, and of ecology. However, work to date has largely been conducted within distinct disciplines. We therefore outline interdisciplinary approaches that can bridge current knowledge gaps in winter limnology.
Key Points
Ecosystems of seasonally ice‐covered lakes are governed by poorly understood interactions between abiotic and biotic processes
Density‐driven currents enable gradients in redox potential, create niche habitats and redistribute substrates and organisms under ice
Winter limnology has tended to progress within disciplines; an interdisciplinary approach is necessary to resolve extant knowledge gaps
•Deprotonated phenol moieties are mainly responsible for persulfate activation.•Redox-active carbonyl moieties activate persulfate when they are reduced.•Terrestrial humic substances (HS) had the ...highest persulfate activation capacities.•High-molecular-weight HS scavenged more radicals than they produced.•Phenol and reduced ketones had different persulfate activation mechanisms.
Persulfate activation through electron transfer from humic substances (HS) was investigated. Persulfate consumption in the presence of standard HS and HS model compounds linearly correlated with the phenol contents of the HS. Redox-active carbonyl groups such as aromatic ketones and quinone also contributed to persulfate consumption by donating electrons while being reduced. Phenols activated persulfate through direct electron transfer from the phenolate forms but reduced ketones activated persulfate through reactions between their organic radicals and persulfate. Persulfate was activated more by terrestrially derived aquatic HS containing large numbers of phenol groups than by other species, and this caused more benzene oxidation to occur in the presence of terrestrially derived aquatic HS than in the presence of other species. Larger amounts of sulfate radicals were scavenged by soil-derived HS than other types of HS because soil-derived HS were composed of larger molecules than other types of HS. The fluorescence regional integration volume for HS reacted with persulfate linearly correlated with persulfate consumption. Decreases in the fluorescence regional integration value could be used to predict persulfate activation through electron transfer from HS to persulfate if the electron-donating capacity cannot be determined. Persulfate activation by HS is expected to be stoichiometrically more advantageous than conventional persulfate–Fe2+ processes when treating an aquifer containing large amounts of electron-rich HS.
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Abstract
Objectives
Observational studies have demonstrated associations between gout and hypertension, but whether they are causal remains unclear. Our work aims to assess the causal relationship ...between gout and hypertension.
Methods
We obtained genetic information from the Taiwan Biobank, including 88,347 participants and 686,439 single-nucleotide polymorphisms (SNPs). A novel model of Mendelian randomisation (MR) with coarsened exposures was used to examine the causality between the liability of gout on hypertension and vice versa, using 4 SNPs associated with gout and 10 SNPs associated with hypertension after removal of SNPs associated with measured confounders. The binary exposure (gout/hypertension) can be considered a coarsened approximation of a latent continuous trait. The inverse-variance weighted (IVW) and polygenic risk score (PRS) methods were used to estimate effect size. The MR analysis with coarsened exposures was performed with and without adjustments for covariates.
Results
Of the 88,347 participants, 3253 (3.68%) had gout and 11,948 (13.52%) had hypertension (men, 31.9%; mean age 51.1 SD, 11.1 years). After adjusting to measured confounders, MR analysis with coarsened exposures showed a significant positive causal effect of the liability of gout on hypertension in both the IVW method (relative risk RR, 1.10; 95% confidence interval CI, 1.03–1.19;
p
= 0.0077) and the PRS method (RR, 1.10; 95% CI, 1.02–1.19;
p
= 0.0092). The result of causality was the same before and after involving measured confounders. However, there was no causal effect of the liability of hypertension on gout.
Conclusions
In this study, we showed that the liability of gout has a causal effect on hypertension, but the liability of hypertension does not have a causal effect on gout. Adequate management of gout may reduce the risk of developing hypertension.
Computational thinking (CT), a way to think about solving problems, is recognized as a basic skill for the 21st century. Although game-based learning (GBL) has been shown to improve student's CT ...skills, students may fail to self-evaluate or debate as they play games, thus failing to develop higher-order thinking. Also not widely explored is how teachers are to practice the CT core competencies during the learning process to cultivate students' problem-solving thinking. As the adoption of student-generated questions (SGQ) is an instructional strategy to promote higher-order thinking, we develop a GBL platform that uses this strategy to enhance students' CT skills, learning motivation, and learning confidence. For this purpose, fifty-three primary school students were recruited for this study, and data were collected during four classes of experimental CT activities. This study shows that the experimental group using the SGQ strategy with a GBL platform exhibited significantly higher CT skills than the control group. In addition, with respect to learning motivation and learning confidence it is found that the experimental group also outperformed the control group. This confirms that integrating the SGQ strategy and CT core competencies fosters higher-order cognitive thinking in students in problem-solving through gamification of the learning environment, resulting in higher motivation and confidence to complete experimental activities.
•This study used student-generated questions (SGQ) in game-based learning platform.•This study integrated five core competencies of computational thinking into SGQ.•This result indicated that SGQ enhanced student's computational thinking skills.•It was studied that SGQ could improve student's learning motivation and confidence.•This study confirmed the contribution of SGQ to computational thinking skills.
We hypothesized that epigenetics is a link between smoking/allergen exposures and the development of Asthma and chronic obstructive pulmonary disease (ACO). A total of 75 of 228 COPD patients were ...identified as ACO, which was independently associated with increased exacerbations. Microarray analysis identified 404 differentially methylated loci (DML) in ACO patients, and 6575 DML in those with rapid lung function decline in a discovery cohort. In the validation cohort, ACO patients had hypermethylated PDE9A (+ 30,088)/ZNF323 (- 296), and hypomethylated SEPT8 (- 47) genes as compared with either pure COPD patients or healthy non-smokers. Hypermethylated TIGIT (- 173) gene and hypomethylated CYSLTR1 (+ 348)/CCDC88C (+ 125,722)/ADORA2B (+ 1339) were associated with severe airflow limitation, while hypomethylated IFRD1 (- 515) gene with frequent exacerbation in all the COPD patients. Hypermethylated ZNF323 (- 296) / MPV17L (+ 194) and hypomethylated PTPRN2 (+ 10,000) genes were associated with rapid lung function decline. In vitro cigarette smoke extract and ovalbumin concurrent exposure resulted in specific DNA methylation changes of the MPV17L / ZNF323 genes, while 5-aza-2'-deoxycytidine treatment reversed promoter hypermethylation-mediated MPV17L under-expression accompanied with reduced apoptosis and decreased generation of reactive oxygen species. Aberrant DNA methylations may constitute a determinant for ACO, and provide a biomarker of airflow limitation, exacerbation, and lung function decline.
Inland waters are increasingly recognized as critical sites of methane emissions to the atmosphere, but the biogeochemical reactions driving such fluxes are less well understood. The Prairie Pothole ...Region (PPR) of North America is one of the largest wetland complexes in the world, containing millions of small, shallow wetlands. The sediment pore waters of PPR wetlands contain some of the highest concentrations of dissolved organic carbon (DOC) and sulfur species ever recorded in terrestrial aquatic environments. Using a suite of geochemical and microbiological analyses, we measured the impact of sedimentary carbon and sulfur transformations in these wetlands on methane fluxes to the atmosphere. This research represents the first study of coupled geochemistry and microbiology within the PPR and demonstrates how the conversion of abundant labile DOC pools into methane results in some of the highest fluxes of this greenhouse gas to the atmosphere ever reported. Abundant DOC and sulfate additionally supported some of the highest sulfate reduction rates ever measured in terrestrial aquatic environments, which we infer to account for a large fraction of carbon mineralization in this system. Methane accumulations in zones of active sulfate reduction may be due to either the transport of free methane gas from deeper locations or the co‐occurrence of methanogenesis and sulfate reduction. If both respiratory processes are concurrent, any competitive inhibition of methanogenesis by sulfate‐reducing bacteria may be lessened by the presence of large labile DOC pools that yield noncompetitive substrates such as methanol. Our results reveal some of the underlying mechanisms that make PPR wetlands biogeochemical hotspots, which ultimately leads to their critical, but poorly recognized role in regional greenhouse gas emissions.
Wetland sediments recovered from the Prairie Pothole Region of North America host microbial communities catalyzing some of the highest sulfate reduction rates ever measured. Concurrently, these same sediments drive some of the highest methane fluxes to atmosphere ever measured. Together, these data indicate that the PPR may play an oversized role in carbon cycling and greenhouse gas fluxes to the atmosphere.
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