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The Science of the Total Environment Jun 2024River invertebrate communities across Europe have been changing in response to variations in water quality over recent decades, but the underlying drivers are difficult...
River invertebrate communities across Europe have been changing in response to variations in water quality over recent decades, but the underlying drivers are difficult to identify because of the complex stressors and environmental heterogeneity involved. Here, using data from ~4000 locations across England and Wales, collected over 29 years, we use three approaches to help resolve the drivers of spatiotemporal variation in the face of this complexity: i) mapping changes in invertebrate richness and community composition; ii) structural equation modelling (SEM) to distinguish land cover, water quality and climatic influences; and iii) geographically weighted regression (GWR) to identify how the apparent relationships between invertebrate communities and abiotic variables change across the area. Mapping confirmed widespread increases in richness and the proportion of pollution-sensitive taxa across much of England and Wales. It also revealed regions where pollution-sensitive taxa or overall richness declined, the former primarily in the uplands. SEMs confirmed strong increases in average biochemical oxygen demand and nutrient concentrations related to urban and agricultural land cover, but only a minority of land cover's effect upon invertebrate communities was explained by average water chemistry, highlighting potential factors such as episodic extremes or emerging contaminants. GWR identified strong geographical variation in estimated relationships between macroinvertebrate communities and environmental variables, with evidence that the estimated negative impacts of nutrients and water temperature were increasing through time. Overall the results are consistent with widespread biological recovery of Britain's rivers from past gross organic pollution, whilst highlighting declines in some of the most diverse and least impacted streams. Modelling points to a complex and changing set of drivers, highlighting the multifaceted impacts of catchment land cover and the evolving role of different stressors, with the relationship to gross organic pollution weakening, whilst estimated nutrient and warming effects strengthened.
PubMed: 38955282
DOI: 10.1016/j.scitotenv.2024.174369 -
The Science of the Total Environment Jun 2024The stratification and turnover dynamics of a tropical lake were evaluated using field observations and 3D hydrodynamic simulations. Located in the Philippines, Sampaloc...
The stratification and turnover dynamics of a tropical lake were evaluated using field observations and 3D hydrodynamic simulations. Located in the Philippines, Sampaloc Lake is a 104-ha and 27-m deep volcanic crater lake with enclosed watershed, which is at risk of the impacts of intensive aquaculture, rapid urbanization and climate change. Temperature, dissolved oxygen (DO) and chlorophyll-a (Chl-a) were measured at seven sampling stations using a multiprobe. Kruskal-Wallis test revealed that the three parameters are not significantly different among stations, indicating that one sampling station can represent the water quality of the whole lake. Schmidt's Stability Index (SSI) and thermocline strength, together with DO and Chl-a gradients decreased from October 2022 (stratified) to January 2023 (turnover). After successfully verifying the 3D numerical model, sensitivity analyses of water temperature to varying weather, together with particle tracking simulations, were implemented to determine the timing of isothermal state, upwelling, partial mixing, and full turnover. Compared to air temperature (AT), variations in wind speed (WS) have more pronounced effects on the delay or progression of isothermal conditions in the lake based on SSI, Lake Number and Wedderburn Number. Isothermal conditions do not necessarily coincide with the timing of full turnover, with the latter being delayed by two days than the former, on average. Results revealed that full turnover can occur several weeks earlier with the decrease in AT and increase in WS. This study can advance the understanding of thermal and turnover dynamics of stratified tropical lakes, leading to better management of the water quality of these water bodies.
PubMed: 38955274
DOI: 10.1016/j.scitotenv.2024.174397 -
Nanotechnology Jul 2024The current work emphasizes the synthesis of a trimetallic core-shell Ag-TeO2@ZnO nanocomposites by thermo-mechanical method for the efficient photocatalytic degradation...
The current work emphasizes the synthesis of a trimetallic core-shell Ag-TeO2@ZnO nanocomposites by thermo-mechanical method for the efficient photocatalytic degradation of 2,4-Dichlorophenol and β-naphthol pollutants. The phase, crystallite size and morphological studies of the prepared Ag-TeO2@ZnO nanocomposites were studied by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. FE-SEM shows that Ag and TeO2 nanoparticles are deposited on the surface of ZnO nanotubes. The synthesized nanocomposite exhibited remarkable photocatalytic performance for the degradation of beta-naphthol (95.6%) in 40 min at the concentration of (0.6 mg/mL) and 2,4-DCP (99.6%) in 180 min (0.4 mg/mL) under natural sunlight. The electrochemical measurements were carried out using cyclic voltammetry and electrochemical impedance spectroscopy. Determination of reactive oxygen species (ROS) confirmed that the degradation of the pollutants by 5wt% Ag-TeO2@ZnO NCs was due to the formation of superoxide radicals. Electron paramagnetic resonance revealed the presence of sharp signals in pure ZnO nanoparticles at g ~1.9530 and oxygen vacancy peak at g~2.01 in 5 wt% Ag-TeO2@ZnO NCs. The reduction in the intensity of oxygen vacancy peak in 5 wt% Ag-TeO2@ZnO NCs resulted in higher ROS generation and, finally enhanced photocatalytic activity. To study the mechanism behind the degradation of pollutants, a scavenger test using histidine and ascorbic acid (ROS scavengers) was performed. The synthesized nanocomposites are highly stable and showed enhanced efficiency up to three cycles, confirming their reusability as a photocatalyst. We believe the synthesis method and the nanocomposite's high photocatalytic activity could be utilized extensively in wastewater treatment under natural sunlight.
PubMed: 38955171
DOI: 10.1088/1361-6528/ad5dc4 -
Nanotechnology Jul 2024Currently, 2D nanomaterials-based RRAMs are explored on account of their tunable material properties enabling fabrication of low power and flexible RRAM devices. In this...
Currently, 2D nanomaterials-based RRAMs are explored on account of their tunable material properties enabling fabrication of low power and flexible RRAM devices. In this work, hybrid MoS-GO based active layer RRAM devices are investigated. A facile hydrothermal co-synthesis approach is used to obtain the hybrid materials and a cost-effective spin coating method adopted for the fabrication of Ag/MoS-GO/ITO RRAM devices. The performance of the fabricated hybrid active layer RRAM device is analysed with respect to change in material properties of the synthesized hybrid material. The progressive addition of 0.5, 1.5, 2.5 and 4.5 weight % of GO to MoS, results in a hybrid active layer with higher intermolecular interaction, in the case of Ag/MoS-GO/ITO RRAM device, resulting in a unipolar resistive switching RRAM behavior with low SET voltage of 1.37 V and high I/Iof 200 with multilevel resistance states. A space charge limited conduction (SCLC) mechanism is obtained during switching, which may be attributed to the trap states present due to functional groups of GO. The increased number of conduction pathways on account of both Agions and oxygen vacancies (V), participating in the formation of conducting filament, results in higher I/I. This is the first report of unipolar Ag/MoS-GO/ITO RRAM devices, which are particularly important in realizing high density crossbar memories for neuromorphic and in-memory computing as well as enabling flexible 2D nanomaterials-based memristor applications.
PubMed: 38955133
DOI: 10.1088/1361-6528/ad5db6 -
Computers in Biology and Medicine Jul 2024This study delves into the therapeutic efficacy of A. pyrethrum in addressing vitiligo, a chronic inflammatory disorder known for inducing psychological distress and...
Inhibition of the Janus kinase protein (JAK1) by the A. Pyrethrum Root Extract for the treatment of Vitiligo pathology. Design, Molecular Docking, ADME-Tox, MD Simulation, and in-silico investigation.
This study delves into the therapeutic efficacy of A. pyrethrum in addressing vitiligo, a chronic inflammatory disorder known for inducing psychological distress and elevating susceptibility to autoimmune diseases. Notably, JAK inhibitors have emerged as promising candidates for treating immune dermatoses, including vitiligo. Our investigation primarily focuses on the anti-vitiligo potential of A. pyrethrum root extract, specifically targeting N-alkyl-amides, utilizing computational methodologies. Density Functional Theory (DFT) is deployed to meticulously scrutinize molecular properties, while comprehensive evaluations of ADME-Tox properties for each molecule contribute to a nuanced understanding of their therapeutic viability, showcasing remarkable drug-like characteristics. Molecular docking analysis probes ligand interactions with pivotal site JAK1, with all compounds demonstrating significant interactions; notably, molecule 6 exhibits the most interactions with crucial inhibition residues. Molecular dynamics simulations over 500ns further validate the importance and sustainability of these interactions observed in molecular docking, favoring energetically both molecules 6 and 1; however, in terms of stability, the complex with molecule 6 outperforms others. DFT analyses elucidate the distribution of electron-rich oxygen atoms and electron-poor regions within heteroatoms-linked hydrogens. Remarkably, N-alkyl-amides extracted from A. pyrethrum roots exhibit similar compositions, yielding comparable DFT and Electrostatic Potential (ESP) results with subtle distinctions. These findings underscore the considerable potential of A. pyrethrum root extracts as a natural remedy for vitiligo.
PubMed: 38955123
DOI: 10.1016/j.compbiomed.2024.108816 -
Redox Biology Jun 2024Ferroptosis, a lipid peroxidation-driven cell death program kept in check by glutathione peroxidase 4 and endogenous redox cycles, promises access to novel strategies...
Ferroptosis, a lipid peroxidation-driven cell death program kept in check by glutathione peroxidase 4 and endogenous redox cycles, promises access to novel strategies for treating therapy-resistant cancers. Chlorido [N,N'-disalicylidene-1,2-phenylenediamine]iron (III) complexes (SCs) have potent anti-cancer properties by inducing ferroptosis, apoptosis, or necroptosis through still poorly understood molecular mechanisms. Here, we show that SCs preferentially induce ferroptosis over other cell death programs in triple-negative breast cancer cells (LC ≥ 0.07 μM) and are particularly effective against cell lines with acquired invasiveness, chemo- or radioresistance. Redox lipidomics reveals that initiation of cell death is associated with extensive (hydroper)oxidation of arachidonic acid and adrenic acid in membrane phospholipids, specifically phosphatidylethanolamines and phosphatidylinositols, with SCs outperforming established ferroptosis inducers. Mechanistically, SCs effectively catalyze one-electron transfer reactions, likely via a redox cycle involving the reduction of Fe(III) to Fe(II) species and reversible formation of oxo-bridged dimeric complexes, as supported by cyclic voltammetry. As a result, SCs can use hydrogen peroxide to generate organic radicals but not hydroxyl radicals and oxidize membrane phospholipids and (membrane-)protective factors such as NADPH, which is depleted from cells. We conclude that SCs catalyze specific redox reactions that drive membrane peroxidation while interfering with the ability of cells, including therapy-resistant cancer cells, to detoxify phospholipid hydroperoxides.
PubMed: 38955113
DOI: 10.1016/j.redox.2024.103257 -
Talanta Jun 2024A modified development protocol and concomitant characterisation of a first generation biosensor for the detection of brain extracellular d-serine is reported....
A modified development protocol and concomitant characterisation of a first generation biosensor for the detection of brain extracellular d-serine is reported. Functional parameters important for neurochemical monitoring, including sensor sensitivity, O interference, selectivity, shelf-life and biocompatibility were examined. Construction and development involved the enzyme d-amino acid oxidase (DAAO), utilising a dip-coating immobilisation method employing a new extended drying approach. The resultant Pt-based polymer enzyme composite sensor achieved high sensitivity to d-serine (0.76 ± 0.04 nA mm. μM) and a low μM limit of detection (0.33 ± 0.02 μM). The in-vitro response time was within the solution stirring time, suggesting potential sub-second in-vivo response characteristics. Oxygen interference studies demonstrated a 1 % reduction in current at 50 μM O when compared to atmospheric O levels (200 μM), indicating that the sensor can be used for reliable neurochemical monitoring of d-serine, free from changes in current associated with physiological O fluctuations. Potential interference signals generated by the principal electroactive analytes present in the brain were minimised by using a permselective layer of poly(o-phenylenediamine), and although several d-amino acids are possible substrates for DAAO, their physiologically relevant signals were small relative to that for d-serine. Additionally, changing both temperature and pH over possible in vivo ranges (34-40 °C and 7.2-7.6 respectively) resulted in no significant effect on performance. Finally, the biosensor was implanted in the striatum of freely moving rats and used to monitor physiological changes in d-serine over a two-week period.
PubMed: 38955102
DOI: 10.1016/j.talanta.2024.126458 -
Spectrochimica Acta. Part A, Molecular... Jun 2024Hypochlorous acid (HClO) as a kind of reactive oxygen species (ROS) plays a vital role in many biological processes. Organic fluorescence probes have attracted great...
Hypochlorous acid (HClO) as a kind of reactive oxygen species (ROS) plays a vital role in many biological processes. Organic fluorescence probes have attracted great interests for the detection of HClO, due to their relatively high selectivity and sensitivity, satisfactory spatiotemporal resolution and good biocompatibility. Constructing fluorescence probes to detect HClO with advantages of large Stokes shift, wide emission gap, near infrared emission and good water solubility is still challenging. In this work, a new ratiometric fluorescence probe (named HCY) for HClO was developed. FRET-based HCY was constructed by bonding a coumarin and a flavone fluorophore. In absence of HClO, HCY exists FRET process, however, FRET is inhibited in the presence of HClO because the conjugated double bond broke. Due to the good match of the emission spectrum of the donor and the absorption spectrum of the acceptor, the FRET system appears favorable energy transfer efficiency. HCY showed high sensitivity and rapid response time. The linearity between the ratios of fluorescence intensity and concentration of HClO was established with a low limit of detection. What's more, HCY was also applied for fluorescence images of HClO in RAW264.7 cells.
PubMed: 38955067
DOI: 10.1016/j.saa.2024.124754 -
Journal of Environmental Management Jul 2024The development of sustainable advanced energy conversion technologies and efficient pollutant treatment processes is a viable solution to the two global crises of the... (Review)
Review
The development of sustainable advanced energy conversion technologies and efficient pollutant treatment processes is a viable solution to the two global crises of the lack of non-renewable energy resources and environmental harm. In recent years, the interaction of biological and chemical oxidation units to utilize biomass has been extensively studied. Among these systems, bio-electro-Fenton (BEF) and photo-bio-electro-Fenton (PBEF) systems have shown prospects for application due to making rational and practical conversion and use of energy. This review compared and analyzed the electron transfer mechanisms in BEF and PBEF systems, and systematically summarized the techniques for enhancing system performance based on the generation, transfer, and utilization of electrons, including increasing the anode electron recovery efficiency, enhancing the generation of reactive oxygen species, and optimizing operational modes. This review compared the effects of different methods on the electron flow process and fully evaluated the benefits and drawbacks. This review may provide straightforward suggestions and methods to enhance the performance of BEF and PBEF systems and inspire the reader to explore the generation and utilization of sustainable energy more deeply.
PubMed: 38955044
DOI: 10.1016/j.jenvman.2024.121633 -
Journal of Environmental Management Jul 2024Hydraulic mixing of stratified reservoirs homogenizes physicochemical gradients and microbial communities. This has potential repercussions for microbial metabolism and...
Hydraulic mixing of stratified reservoirs homogenizes physicochemical gradients and microbial communities. This has potential repercussions for microbial metabolism and water quality, not least in dams and hydraulically controlled waters. A better understanding of how key taxa respond to mixing of such stratified water bodies is needed to understand and predict the impact of hydraulic operations on microbial communities and nutrient dynamics in reservoirs. We studied taxa transitions between cyanobacteria and sulfur-transforming bacteria following mixing of stratified water columns in bioreactors and complemented the experimental approach with a biogeochemical model. Model predictions were consistent with experimental observations, suggesting that stable stratification of DO is restored within 24 h after episodic and complete mixing, at least in the absence of other more continuous disturbances. Subsequently, the concentration of S gradually return to pre-mixing states, with higher concentration at the surface and lower in the bottom waters, while the opposite pattern was seen for SO. The total abundance of sulfate-reducing bacteria and phototrophic sulfur bacteria increased markedly after 24h of mixing. The model further predicted that the rapid re-oxygenation of the entire water column by aeration will effectively suppress the water stratification and the growth of sulfur-transforming bacteria. Based on these results, we suggest that a reduction of thermocline depth by optimal flow regulation in reservoirs may also depress sulfur transforming bacteria and thereby constrain sulfur transformation processes and pollutant accumulation. The simulation of microbial nutrient transformation processes in vertically stratified waters can provide new insights about effective environmental management measures for reservoirs.
PubMed: 38955043
DOI: 10.1016/j.jenvman.2024.121651