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Molecules (Basel, Switzerland) Feb 2020Nitroxides are broadly used as molecular probes and labels in biophysics, structural biology, and biomedical research. Resistance of a nitroxide group bearing an...
Nitroxides are broadly used as molecular probes and labels in biophysics, structural biology, and biomedical research. Resistance of a nitroxide group bearing an unpaired electron to chemical reduction with low-molecular-weight antioxidants and enzymatic systems is of critical importance for these applications. The redox properties of nitroxides are known to depend on the ring size (for cyclic nitroxides) and electronic and steric effects of the substituents. Here, two highly strained nitroxides, 5-(-butyl)-5-butyl-2,2-diethyl-3-hydroxypyrrolidin-1-oxyl () and 2-(-butyl)-2-butyl-5,5-diethyl-3,4-bis(hydroxymethyl)pyrrolidin-1-oxyl (), were prepared via a reaction of the corresponding 2--butyl-1-pyrroline 1-oxides with butyllithium. Thermal stability and kinetics of reduction of the new nitroxides by ascorbic acid were studied. Nitroxide showed the highest resistance to reduction.
Topics: Antioxidants; Biomedical Research; Electron Transport; Nitrogen Oxides; Organometallic Compounds; Oxidation-Reduction; Oxides; Pyrroles
PubMed: 32075085
DOI: 10.3390/molecules25040845 -
Sensors (Basel, Switzerland) May 2021Semiconductor (SC)-based field-effect transistors (FETs) have been demonstrated as amazing enhancer gadgets due to their delicate interface towards surface adsorption.... (Review)
Review
Semiconductor (SC)-based field-effect transistors (FETs) have been demonstrated as amazing enhancer gadgets due to their delicate interface towards surface adsorption. This leads to their application as sensors and biosensors. Additionally, the semiconductor material has enormous recognizable fixation extends, high affectability, high consistency for solid detecting, and the ability to coordinate with other microfluidic gatherings. This review focused on current progress on the semiconductor-interfaced FET biosensor through the fundamental interface structure of sensor design, including inorganic semiconductor/aqueous interface, photoelectrochemical interface, nano-optical interface, and metal-assisted interface. The works that also point to a further advancement for the trademark properties mentioned have been reviewed here. The emergence of research on the organic semiconductor interface, integrated biosensors with Complementary metal-oxide-semiconductor (CMOS)-compatible, metal-organic frameworks, has accelerated the practical application of biosensors. Through a solid request for research along with sensor application, it will have the option to move forward the innovative sensor with the extraordinary semiconductor interface structure.
Topics: Biosensing Techniques; Metals; Oxides; Semiconductors; Transistors, Electronic
PubMed: 34065696
DOI: 10.3390/s21103467 -
Chemosphere Jan 2022Recently, modifications on reticulated vitreous carbon (RVC) have attracted attention as a promising strategy to produce low-cost, stable, and highly active electrodes... (Review)
Review
Recently, modifications on reticulated vitreous carbon (RVC) have attracted attention as a promising strategy to produce low-cost, stable, and highly active electrodes leading to significant advances in the water/wastewater treatment field compared with raw RVC. Modified RVC materials have been used as cathode, anode, and membrane. Improvements on physical and electrocatalytic properties are achieved by RVC modification via diverse strategies, including the deposition of metal oxides, the introduction of surface functional groups, and the formation of composites, which were used to remove organic contaminants and pathogens from water matrices, as summarized in this mini-review. This mini-review mainly focused on papers published from 2015 to 2020 that reported modified RVC electrodes to eliminate pollutants and pathogens from water matrices by electrochemical advanced oxidation processes. Likewise, news challenges and opportunities are discussed, and perspectives for the ongoing and future studies in this research field are also given.
Topics: Carbon; Electrodes; Oxidation-Reduction; Wastewater; Water; Water Purification
PubMed: 34303050
DOI: 10.1016/j.chemosphere.2021.131573 -
BMC Plant Biology Jun 2023Most nanoparticles (NPs) have a significant impact on the structure and function of the plant photosynthetic apparatus. However, their spectrum of action varies...
BACKGROUND
Most nanoparticles (NPs) have a significant impact on the structure and function of the plant photosynthetic apparatus. However, their spectrum of action varies significantly, from beneficial stimulation to toxicity, depending on the type of NPs, the concentration used and plant genotypic diversity. Photosynthetic performance can be assessed through chlorophyll a fluorescence (ChlF) measurements. These data allow to indirectly obtain detailed information about primary light reactions, thylakoid electron transport reactions, dark enzymatic stroma reactions, slow regulatory processes, processes at the pigment level. It makes possible, together with leaf reflectance performance, to evaluate photosynthesis sensitivity to stress stimuli.
RESULTS
We investigated effects of different metal and metal(oid) oxide nanoparticles on photosynthesis of oakleaf lettuce seedlings by monitoring the chlorophyll a fluorescence light radiation and reflectance from the leaves. Observations of ChlF parameters and changes in leaf morphology were carried out for 9 days in two-day intervals. Spectrophotometric studies were performed at 9 day. Suspensions of NPs with the following concentrations were used: 6% TiO, SiO; 3% CeO, SnO, FeO; 0.004% (40 ppm) Ag; 0.002% (20 ppm) Au. Nanoparticles were applied directly on the leaves which caused small symptoms of chlorosis, necrosis and leaf veins deformation, but the plants fully recovered to the initial morphological state at 9 day. Leaf reflectance analysis showed an increase in FRI for SiO-NPs and CeO-NPs treatments and ARI2 for FeO, however, WBI and PRI coefficients for the latter nanoparticle were lower than in control. Chlorophyll a fluorescence parameters have changed due to NPs treatment. FeO-NPs caused an increase in F/F, PI, ET/RC, DI/RC, ABS/RC in different time points in comparison to control, also Ag, Au and SnO treatment caused an increase in F/F, PI or ET/RC, respectively. On the other hand, TiO-NPs caused a decrease in F/F and F/F parameters, but an increase in DI/RC value was observed. SnO-NPs decreased PI, but increased ET/RC than compared to control. Nanoparticles affected the shape of the O-J-I-P curve in slight manner, however, further analyses showed unfavourable changes within the PSII antenna, manifested by a slowdown in the transport of electrons between the Chl molecules of the light-harvesting complex II and the active center of PSII due to NPs application.
CONCLUSION
Changes in ChlF parameters and leaf reflectance values clearly proved the significant influence of NPs on the functioning of the photosynthetic apparatus, especially right after NPs application. The nature of these changes was strictly depended on the type of nanoparticles and sometimes underwent very significant changes over time. The greatest changes in ChlF parameters were caused by FeO nanoparticles, followed by TiO-NPs. After slight response of O-J-I-P curves to treatment of the plants with NPs the course of the light phase of photosynthesis stabilized and at 9 day were comparable to the control curve.
Topics: Chlorophyll A; Chlorophyll; Lactuca; Oxides; Fluorescence; Silicon Dioxide; Photosystem II Protein Complex; Plant Leaves; Nanoparticles
PubMed: 37340375
DOI: 10.1186/s12870-023-04305-9 -
Scientific Reports Jun 2023Increased levels of nutrients and algae can cause drinking water problems in communities. Harmful algal blooms affect humans, fish, marine mammals, birds, and other...
Increased levels of nutrients and algae can cause drinking water problems in communities. Harmful algal blooms affect humans, fish, marine mammals, birds, and other animals. In the present study, we investigated the use of a combined system [Hydrodynamic Cavitation, Ozone (O), and Hydrogen Peroxide (HO)] on the removal of Chlorophyll a and Organic substances in the raw water was investigated. The Effect of different operating conditions such as pH, cavitation time, pressure, distance, flow rate, ozone dose, and hydrogen peroxide concentration was studied. Utilizing the Taguchi design method, experiments were planned and optimized. The combined system treatment yielded a maximum reduction in Chlorophyll a and Total Organic Carbon (TOC) at an optimum condition of pH 5, cavitation pressure 5 bar, flow rate of 1 m/h, a distance of 25 cm from the orifice plate, O 3 g/h and 2 g/l of HO concentrations. The most efficient factor in the degradation of TOC and Chlorophyll a, was cavitation pressure based on the percentage contributions of each parameter (38.64 percent and 35.05 percent, respectively). HO was found to have the most negligible impact on degradation efficiency (4.24 percent and 4.11 percent, respectively).
Topics: Humans; Chlorophyll A; Hydrogen Peroxide; Hydrodynamics; Ozone; Water Purification; Drinking Water; Water Pollutants, Chemical; Oxidation-Reduction
PubMed: 37344539
DOI: 10.1038/s41598-023-37167-0 -
Nature Communications Feb 2022Artificial photosynthesis of HO using earth-abundant water and oxygen is a promising approach to achieve scalable and cost-effective solar fuel production. Recent...
Artificial photosynthesis of HO using earth-abundant water and oxygen is a promising approach to achieve scalable and cost-effective solar fuel production. Recent studies on this topic have made significant progress, yet are mainly focused on using organic polymers. This set of photocatalysts is susceptible to potent oxidants (e.g. hydroxyl radical) that are inevitably formed during HO generation. Here, we report an inorganic Mo-doped faceted BiVO (Mo:BiVO) system that is resistant to radical oxidation and exhibits a high overall HO photosynthesis efficiency among inorganic photocatalysts, with an apparent quantum yield of 1.2% and a solar-to-chemical conversion efficiency of 0.29% at full spectrum, as well as an apparent quantum yield of 5.8% at 420 nm. The surface-reaction kinetics and selectivity of Mo:BiVO were tuned by precisely loading CoO and Pd on {110} and {010} facets, respectively. Time-resolved spectroscopic investigations of photocarriers suggest that depositing select cocatalysts on distinct facet tailored the interfacial energetics between {110} and {010} facets and enhanced charge separation in Mo:BiVO, therefore overcoming a key challenge in developing efficient inorganic photocatalysts. The promising HO generation efficiency achieved by delicate design of catalyst spatial and electronic structures sheds light on applying robust inorganic particulate photocatalysts to artificial photosynthesis of HO.
Topics: Catalysis; Hydrogen Peroxide; Photosynthesis; Semiconductors; Water
PubMed: 35210427
DOI: 10.1038/s41467-022-28686-x -
Biomolecules Mar 2021Heavy metals (HMs) toxicity represents a global problem depending on the soil environment's geochemical forms. Biochar addition safely reduces HMs mobile forms, thus,...
Heavy metals (HMs) toxicity represents a global problem depending on the soil environment's geochemical forms. Biochar addition safely reduces HMs mobile forms, thus, reducing their toxicity to plants. While several studies have shown that biochar could significantly stabilize HMs in contaminated soils, the study of the relationship of soil properties to potential mechanisms still needs further clarification; hence the importance of assessing a naturally contaminated soil amended, in this case with Paulownia biochar (PB) and Bamboo biochar (BB) to fractionate Pb, Cd, Zn, and Cu using short sequential fractionation plans. The relationship of soil pH and organic matter and its effect on the redistribution of these metals were estimated. The results indicated that the acid-soluble metals decreased while the fraction bound to organic matter increased compared to untreated pots. The increase in the organic matter metal-bound was mostly at the expense of the decrease in the acid extractable and Fe/Mn bound ones. The highest application of PB increased the organically bound fraction of Pb, Cd, Zn, and Cu (62, 61, 34, and 61%, respectively), while the BB increased them (61, 49, 42, and 22%, respectively) over the control. Meanwhile, Fe/Mn oxides bound represents the large portion associated with zinc and copper. Concerning soil organic matter (SOM) and soil pH, as potential tools to reduce the risk of the target metals, a significant positive correlation was observed with acid-soluble extractable metal, while a negative correlation was obtained with organic matter-bound metal. The principal component analysis (PCA) shows that the total variance represents 89.7% for the TCPL-extractable and HMs forms and their relation to pH and SOM, which confirms the positive effect of the pH and SOM under PB and BB treatments on reducing the risk of the studied metals. The mobility and bioavailability of these metals and their geochemical forms widely varied according to pH, soil organic matter, biochar types, and application rates. As an environmentally friendly and economical material, biochar emphasizes its importance as a tool that makes the soil more suitable for safe cultivation in the short term and its long-term sustainability. This study proves that it reduces the mobility of HMs, their environmental risks and contributes to food safety. It also confirms that performing more controlled experiments, such as a pot, is a disciplined and effective way to assess the suitability of different types of biochar as soil modifications to restore HMs contaminated soil via controlling the mobilization of these minerals.
Topics: Cadmium; Charcoal; Chemical Fractionation; Copper; Environmental Pollution; Ferric Compounds; Hydrogen-Ion Concentration; Lamiales; Lead; Manganese Compounds; Metals, Heavy; Microscopy, Electron, Scanning; Organic Chemicals; Oxides; Principal Component Analysis; Sasa; Soil; Spectrometry, X-Ray Emission; Zinc
PubMed: 33802758
DOI: 10.3390/biom11030448 -
Scientific Reports Dec 2022Conventional nitrogen removal in wastewater treatment requires a high oxygen and energy input. Anaerobic ammonium oxidation (anammox), the single-step conversion of...
Conventional nitrogen removal in wastewater treatment requires a high oxygen and energy input. Anaerobic ammonium oxidation (anammox), the single-step conversion of ammonium and nitrite to nitrogen gas, is a more energy and cost effective alternative applied extensively to sidestream wastewater treatment. It would also be a mainstream treatment option if species diversity and physiology were better understood. Anammox bacteria were enriched up to 80%, 90% and 50% relative abundance, from a single inoculum, under standard enrichment conditions with either stepwise-nitrite and ammonia concentration increases (R1), nitric oxide supplementation (R2), or complex organic carbon from mainstream wastewater (R3), respectively. Candidatus Brocadia caroliniensis predominated in all reactors, but a shift towards Ca. Brocadia sinica occurred at ammonium and nitrite concentrations > 270 mg NH-N L and 340 mg NO-N L respectively. With NO present, heterotrophic growth was inhibited, and Ca. Jettenia coexisted with Ca. B. caroliniensis before diminishing as nitrite increased to 160 mg NO-N L. Organic carbon supplementation led to the emergence of heterotrophic communities that coevolved with Ca. B. caroliniensis. Ca. B. caroliniensis and Ca. Jettenia preferentially formed biofilms on surfaces, whereas Ca. Brocadia sinica formed granules in suspension. Our results indicate that multiple anammox bacteria species co-exist and occupy sub-niches in anammox reactors, and that the dominant population can be reversibly shifted by, for example, changing nitrogen load (i.e. high nitrite concentration favors Ca. Brocadia caroliniensis). Speciation has implications for wastewater process design, where the optimum cell immobilization strategy (i.e. carriers vs granules) depends on which species dominates.
Topics: Wastewater; Carbon; Nitrites; Anaerobic Ammonia Oxidation; Nitrogen Dioxide; Oxidation-Reduction; Ammonium Compounds; Nitrogen; Bacteria; Biotransformation; Biofilms; Bioreactors; Anaerobiosis
PubMed: 36522527
DOI: 10.1038/s41598-022-26069-2 -
International Journal of Molecular... Oct 2022Cu nanoparticles were produced by using solid-state dewetting (dry) of a 1.3 nm Cu layer or laser ablation of a Cu solid target (wet) in acetone and methanol. The...
Cu nanoparticles were produced by using solid-state dewetting (dry) of a 1.3 nm Cu layer or laser ablation of a Cu solid target (wet) in acetone and methanol. The morphology and chemical composition of the nanoparticles were investigated as a function of the synthesis methods and their key parameters of the annealing temperature (200-500 °C) and the liquid environment during the ablation. Cu nanoparticles were then embedded in transparent conductive oxide (TCO) films as aluminum-doped zinc oxide (AZO) or zirconium-doped indium oxide (IZrO); the TCO/Cu nanoparticle/TCO structures were synthesized with all combinations of AZO and IZrO as the top and bottom layers. The goal was to achieve a plasmonic and conductive structure for photovoltaic applications via a comparison of the involved methods and all fabricated structures. In particular, solid-state dewetting produced faceted or spherical (depending on the annealing temperature) nanoparticles with an average size below 150 nm while laser ablation produced spherical nanoparticles below 250 nm. Dry and wet plasmonic conductive structures as a function of the TCOs employed and the temperature of annealing could reach a sheet resistance of 86 Ω/sq. The energy band-gap E, absorbance, transmittance, and reflectance of the plasmonic conductive structures were investigated in the UV-vis-NIR range. They showed a dependence on the sequence of the top and bottom TCO, with best transmittances of 89.4% for the dry plasmonic conductive structure and 84.7% for the wet plasmonic conductive structure. The latter showed a higher diffused transmittance of between 10-20% in the visible range.
Topics: Acetone; Aluminum; Methanol; Nanoparticles; Organic Chemicals; Oxides; Zinc; Zinc Oxide; Zirconium
PubMed: 36233188
DOI: 10.3390/ijms231911886 -
Organic Letters May 2020For decades, oxidative dearomatization has been employed as a key step in the synthesis of complex molecules. Challenges in controlling the chemo- and site-selectivity...
For decades, oxidative dearomatization has been employed as a key step in the synthesis of complex molecules. Challenges in controlling the chemo- and site-selectivity of this transformation have sparked the development of a variety of specialized oxidants; however, these result in stoichiometric amounts of organic byproducts. Herein, we describe a photocatalytic method for oxidative dearomatization using molecular oxygen as the stoichiometric oxidant. This provides environmentally benign entry to highly substituted -quinols, reactive intermediates which can be elaborated to a number of natural product families.
Topics: Benzaldehydes; Catalysis; Hydroquinones; Oxidants, Photochemical; Oxidation-Reduction; Photochemical Processes
PubMed: 32293185
DOI: 10.1021/acs.orglett.0c01207