Multi-layered Barium and Strontium Carbonate Structures Induced by the Small Organic Dye Acid Orange 7
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ABSTRACT:
SUBMITTER: Mader A
PROVIDER: S-EPMC8569680 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The physiological and transcriptomic response of the metal resistant bacterium Cupriavidus metallidurans strain CH34 in response to stable (non-radioactive) strontium ions (Sr) was investigated. C. metallidurans CH34 could survive and proliferate in the presence of relatively high concentrations of SrCl2 (D10 is 70mM, MIC is 120 mM). Precipitation of Sr as strontium carbonate was observed in the culture during aerobic growth of CH34 in the presence of 60 mM SrCl2. To identify the cellular mechanisms involved in the bioprecipitation process, gene expression in the cells was analyzed after short-time (30 min) exposure to low (5 mM) and high (60 mM) concentrations of SrCl2. The transcription of the gene clusters annotated as hmyFCBA and czcCBADRS, coding for ion efflux pumps, was significantly induced following exposure to Sr, and not with Ca. There were also significant changes is the transcription of the genes encoding TctCBA proteins involved in citrate uptake and two hypothetical porin coding genes following exposure Sr and Ca. These results highlight a specific molecular response of bacterium Cupriavidus metallidurans CH34 to Sr, including the identification of putative Sr specific efflux pumps, and thus the potential of this bacterium to distinguish Sr from Ca. These findings will help to better understand natural Sr (and Ca) microbial weathering or mineralization processes in the environment, and could be of interest for bioremediation or bioprocessing of (radioactive) Sr-containing water, soil or waste.
2012-06-07 | GSE29863 | GEO
Project description:The title compound, Sr0.6Ba0.4Nb2O6 (strontium barium niobium oxide), belongs to the group of strontium-barium niobates with varying composition of Sr and Ba. Their general formula can be written as Sr x Ba1 - x Nb2O6. Below the Curie temperature, T c , these materials indicate ferroelectric properties. The Curie temperature for SBN60 is equal to 346±0.5?K so the structure is in the ferroelectric phase at the measurement temperature of 100?K. Characteristic for this family of compounds is the packing along the z-axis. The NbO6 corner-sharing octa-hedra surround three types of vacancy tunnels with penta-gonal, square and triangular shapes. The Sr(2+) ions partially occupy two unique sites, the first one located inside the penta-gon and the second one in the square tunnels. Consequently, they are situated on the mirror plane and the inter-section of two glide planes, respectively. The site inside the penta-gonal tunnel is additionally disordered so that the same position is shared by Ba(2+) and Sr(2+) ions whereas another part of the Ba(2+) ion occupies a different position (relative occupancies 0.43:0.41:0.16). One of the Nb(V) atoms and three of the O(2-) ions occupy general positions. The second Nb(V) atom is located on the inter-section of the mirror planes. Two remaining O(2-) ions are located on the same mirror plane. Only the Nb(V) atom and one of the O(2-) ions which is located on the mirror plane are not disordered. Each of the remaining O(2-) ions is split between two sites, with relative occupancies of 0.52:0.48 (O(2-) ions in general positions) and 0.64:0.36 (O(2-) ion on the mirror plane).
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Project description:The physiological and transcriptomic response of the metal resistant bacterium Cupriavidus metallidurans strain CH34 in response to stable (non-radioactive) strontium ions (Sr) was investigated. C. metallidurans CH34 could survive and proliferate in the presence of relatively high concentrations of SrCl2 (D10 is 70mM, MIC is 120 mM). Precipitation of Sr as strontium carbonate was observed in the culture during aerobic growth of CH34 in the presence of 60 mM SrCl2. To identify the cellular mechanisms involved in the bioprecipitation process, gene expression in the cells was analyzed after short-time (30 min) exposure to low (5 mM) and high (60 mM) concentrations of SrCl2. The transcription of the gene clusters annotated as hmyFCBA and czcCBADRS, coding for ion efflux pumps, was significantly induced following exposure to Sr, and not with Ca. There were also significant changes is the transcription of the genes encoding TctCBA proteins involved in citrate uptake and two hypothetical porin coding genes following exposure Sr and Ca. These results highlight a specific molecular response of bacterium Cupriavidus metallidurans CH34 to Sr, including the identification of putative Sr specific efflux pumps, and thus the potential of this bacterium to distinguish Sr from Ca. These findings will help to better understand natural Sr (and Ca) microbial weathering or mineralization processes in the environment, and could be of interest for bioremediation or bioprocessing of (radioactive) Sr-containing water, soil or waste. Two-condition experiments. Comparing samples after induction with metals (Sr, Ca) versus non-induced samples. Biological triplicate. Each array contains 3 technical replicates.
2012-06-06 | E-GEOD-29863 | biostudies-arrayexpress
Project description:Hybrid structures with an interface between two different materials with properly aligned energy levels facilitate photo-induced charge separation to be exploited in optoelectronic applications. Particularly, the combination of 2D transition metal dichalcogenides (TMDCs) and dye molecules offers strong light-matter interaction, tailorable band level alignments, and high fluorescence quantum yields. In this work, we aim at the charge or energy transfer-related quenching of the fluorescence of the dye perylene orange (PO) when isolated molecules are brought onto monolayer TMDCs via thermal vapor deposition. Here, micro-photoluminescence spectroscopy revealed a strong intensity drop of the PO fluorescence. For the TMDC emission, in contrast, we observed a relative growth of the trion versus exciton contribution. In addition, fluorescence imaging lifetime microscopy quantified the intensity quenching to a factor of about 103 and demonstrated a drastic lifetime reduction from 3 ns to values much shorter than the 100 ps width of the instrument response function. From the ratio of the intensity quenching that is attributed to hole or energy transfer from dye to semiconductor, we deduce a time constant of several picoseconds at most, pointing to an efficient charge separation suitable for optoelectronic devices.
| S-EPMC10263002 | biostudies-literature
Project description:In this report, we explore the internal structural features of polyMOFs consisting of equal mass ratios of metal-coordinating poly(benzenedicarboxylic acid) blocks and non-coordinating poly(ethylene glycol) (PEG) blocks. The studies reveal alternating lamellae of metal-rich, crystalline regions and metal-deficient non-crystalline polymer, which span the length of hundreds of nanometers. Polymers consisting of random PEG blocks, PEG end-blocks, or non-coordinating poly(cyclooctadiene) (COD) show similar alternation of metal-rich and metal-deficient regions, indicating a universal self-assembly mechanism. A variety of techniques were employed to interrogate the internal structure of the polyMOFs, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and small-angle synchrotron X-ray scattering (SAXS). Independent of the copolymer architecture or composition, the internal structure of the polyMOF crystals showed similar lamellar self-assembly at single-nanometer length scales.
| S-EPMC8162296 | biostudies-literature
Project description:Photochemical activation is proposed as a general method for controlling the crystallization of sparingly soluble carbonates in space and time. The photogeneration of carbonate in an alkaline environment is achieved upon photo-decarboxylation of an organic precursor by using a conventional 365 nm UV LED. Local irradiation was conducted focusing the LED light on a 300 μm radius spot on a closed glass crystallization cell. The precursor solution was optimized to avoid the precipitation of the photoreaction organic byproducts and prevent photo-induced pH changes to achieve the formation of calcium carbonate only in the corresponding irradiated area. The crystallization was monitored in real-time by time-lapse imaging. The method is also shown to work in gels. Similarly, it was also shown to photo-activate locally the formation of barium carbonate biomorphs. In the last case, the morphology of these biomimetic structures was tuned by changing the irradiation intensity.
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Project description:Biomineralization is a ubiquitous process in organisms to produce biominerals, and a wide range of metallic nanoscale minerals can be produced as a consequence of the interactions of micro-organisms with metals and minerals. Copper-bearing nanoparticles produced by biomineralization mechanisms have a variety of applications due to their remarkable catalytic efficiency, antibacterial properties and low production cost. In this study, we demonstrate the biotechnological potential of copper carbonate nanoparticles (CuNPs) synthesized using a carbonate-enriched biomass-free ureolytic fungal spent culture supernatant. The efficiency of the CuNPs in pollutant remediation was investigated using a dye (methyl red) and a toxic metal oxyanion, chromate Cr(VI). The biogenic CuNPs exhibited excellent catalytic properties in a Fenton-like reaction to degrade methyl red, and efficiently removed Cr(VI) from solution due to both adsorption and reduction of Cr(VI). X-ray photoelectron spectroscopy (XPS) identified the oxidation of reducing Cu species of the CuNPs during the reaction with Cr(VI). This work shows that urease-positive fungi can play an important role not only in the biorecovery of metals through the production of insoluble nanoscale carbonates, but also provides novel and simple strategies for the preparation of sustainable nanomineral products with catalytic properties applicable to the bioremediation of organic and metallic pollutants, solely and in mixtures.
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Project description:This study investigates the impact of Sr doping on the tribocatalytic performance of BaTiO3 in degrading organic pollutants. Ba1-xSrxTiO3 (x = 0-0.3) nanopowders are synthesized and their tribocatalytic performance evaluated. By doping Sr into BaTiO3, the tribocatalytic performance was enhanced, resulting in an approximately 35% improvement in the degradation efficiency of Rhodamine B using Ba0.8Sr0.2TiO3. Factors such as the friction contact area, stirring speed, and materials of the friction pairs also influenced the dye degradation. Electrochemical impedance spectroscopy revealed that Sr doping improved BaTiO3's charge transfer efficiency, thereby boosting its tribocatalytic performance. These findings indicate potential applications for Ba1-xSrxTiO3 in dye degradation processes.
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Project description:A Metal-Organic Framework (MOF), iron-benzenetricarboxylate (Fe(BTC)), has been studied for the adsorptive removal of azo-dye Orange II from aqueous solutions, where the effect of various parameters was tested and isotherm and kinetic models were suggested. The adsorption capacities of Fe(BTC) were much higher than those of an activated carbon. The experimental data can be best described by the Langmuir isotherm model (R² > 0.997) and revealed the ability of Fe(BTC) to adsorb 435 mg of Orange II per gram of adsorbent at the optimal conditions. The kinetics of Orange II adsorption followed a pseudo-second-order kinetic model, indicating the coexistence of physisorption and chemisorption, with intra-particle diffusion being the rate controlling step. The thermodynamic study revealed that the adsorption of Orange II was feasible, spontaneous and exothermic process (-25.53 kJ·mol-1). The high recovery of the dye showed that Fe(BTC) can be employed as an effective and reusable adsorbent for the removal of Orange II from aqueous solutions and showed the economic interest of this adsorbent material for environmental purposes.
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Project description:Lactation length and weaning age provide important information about maternal investment, which can reflect the health and nutritional status of the mother, as well as broader reproductive strategies in mammals. Calcium-normalized strontium (Sr) and barium (Ba) concentrations in the growth layers of mammalian teeth differ for nursing animals and those consuming non-milk foods, thus can be used to estimate age-at-weaning. To date, this approach has been used only for terrestrial animals, and almost exclusively for primates.The goal of this study was to determine whether Sr and Ba concentrations in the cementum of Pacific walrus Odobenus rosmarus divergens teeth can be used to estimate weaning age. Teeth from 107 walruses were analysed using laser ablation inductively coupled plasma mass spectrometry, and calcium-normalized 88Sr and 137Ba concentrations were quantified.For most walruses, both Sr and Ba concentrations exhibited rapid changes in early life. Ba concentrations matched closely with expected patterns in the published literature, rapidly declining from high to low concentrations (typically from ~10 ppm to ~5 ppm). In contrast, Sr exhibited a pattern opposite to that presented in studies of terrestrial mammals, appearing nearly identical to Ba (typically declining from ~400 ppm to ~200 ppm). To explain these findings, we present conceptual models of the factors generating weaning signals in Sr and Ba for terrestrial mammals, as well as a new, hypothetical model for walruses. Both a visual and mathematical approach to weaning age estimation indicated a median weaning age of walruses at the end of the second year of life (in the second dark layer of the tooth cementum), with many walruses estimated to have weaned in their third year of life, and a smaller group weaning in their fourth or fifth year. This is later than expected, given a published estimate of walrus weaning at 18-24 months.These results do not conclusively support the use of tooth Sr and Ba for estimating weaning age in walruses, and further research is warranted to better understand the drivers of the observed patterns of Ba and Sr accumulation in walrus teeth.
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