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Schematic representation of the N-doped graphene as prepared and after light irradiation under ambient conditions. The blue spheres represent nitrogen atoms. The three different C–N bonding configurations inserted into the graphene network are evidenced in the as prepared G:N, as well as the typical carbon vacancy (blue area) and the Stone–Wales ( yellow area) defects. Following light irradiation, two new functionalities are introduced: Pyridine N-oxide and Pyridone. Among the three different tautomeric forms of pyridone it is emphasized the net charge separation in zwitterion pyridone-III as well as in pyridine N-oxide, thus resulting in a more p-doped.
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Nitrogen substitutional doping in the π-basal plane of graphene has been used to modulate the material properties and in particular the transition from hole to electron conduction, thus enlarging the field of potential applications. Depending on the doping procedure, nitrogen moieties mainly include graphitic-N, combined with pyrrolic-N and pyridin...
Citations
... When a proper amount of fertilizer was applied (138 kg/ha) it increased the pigment PS II and photosynthetic area of the leaf [2]. In the case of sugar beet, the highest content of chlorophyll and highest productivity was obtained when the application of Nitrogen was 120 kg/ha [34]. High nitrogen concentration increases potassium, phosphorus, iron, calcium, magnesium, and copper uptake in plants by promoting root growth, altering PH, stimulating microbial activity, and increasing the solubility of these fertilizers. ...
Plant growth and resilience to abiotic stresses, such as soil salinity and drought, depend intricately on nitrogen metabolism. This review explores nitrogen’s regulatory role in plant responses to these challenges, unveiling a dynamic interplay between nitrogen availability and abiotic stress. In the context of soil salinity, a nuanced relationship emerges, featuring both antagonistic and synergistic interactions between salinity and nitrogen levels. Salinity-induced chlorophyll depletion in plants can be alleviated by optimal nitrogen supplementation; however, excessive nitrogen can exacerbate salinity stress. We delve into the complexities of this interaction and its agricultural implications. Nitrogen, a vital element within essential plant structures like chloroplasts, elicits diverse responses based on its availability. This review comprehensively examines manifestations of nitrogen deficiency and toxicity across various crop types, including cereals, vegetables, legumes, and fruits. Furthermore, we explore the broader consequences of nitrogen products, such as N2O, NO2, and ammonia, on human health. Understanding the intricate relationship between nitrogen and salinity, especially chloride accumulation in nitrate-fed plants and sodium buildup in ammonium-fed plants, is pivotal for optimizing crop nitrogen management. However, prudent nitrogen use is essential, as overapplication can exacerbate nitrogen-related issues. Nitrogen Use Efficiency (NUE) is of paramount importance in addressing salinity challenges and enhancing sustainable crop productivity. Achieving this goal requires advancements in crop varieties with efficient nitrogen utilization, precise timing and placement of nitrogen fertilizer application, and thoughtful nitrogen source selection to mitigate losses, particularly urea-based fertilizer volatilization. This review article delves into the multifaceted world of plant nitrogen metabolism and its pivotal role in enabling plant resilience to nutritional stress and abiotic challenges. It offers insights into future directions for sustainable agriculture.
... The results of EPR measurements did not show any singlet oxygen generation, either after the exposure of the composite samples to blue or green light (Figure 3b). It was shown [59] that functional groups with N quench singlet oxygen. In our previous study [25], XPS analysis showed the presence of NCO and NH groups in BC-ChiD composites, which are responsible for the quenching of singlet oxygen. ...
In this study, nanochitosan dots (ChiDs) were synthesized using gamma rays and encapsulated in bacterial cellulose (BC) polymer matrix for antibiofilm potential in photodynamic therapy. The composites were analyzed for structural changes using SEM, AFM, FTIR, XRD, EPR, and porosity measurements. Additionally, ChiD release was assessed. The results showed that the chemical composition remained unaltered, but ChiD agglomerates embedded in BC changed shape (1.5–2.5 µm). Bacterial cellulose fibers became deformed and interconnected, with increased surface roughness and porosity and decreased crystallinity. No singlet oxygen formation was observed, and the total amount of released ChiD was up to 16.10%. Antibiofilm activity was higher under green light, with reductions ranging from 48 to 57% under blue light and 78 to 85% under green light. Methicillin-resistant Staphylococcus aureus was the most sensitive strain. The new photoactive composite hydrogels show promising potential for combating biofilm-related infections.
... The result of deconvoluting the high-resolution spectra of the overlapping of photoemission lines for N1s and Mo3p3/2 indicates the presence of components corresponding to the compounds MoN, MoO2, MoOx, and MoO3 (Table 4), which agrees with the results obtained in Figure 4a,b. 228.95 [43] 229.4 [44] 231.90 [45] 232.70 [46] 399.80 [47] 398.80 [47] 401.50 [47] 402.3 [47] 397.05 [43] * N5-pyrrole-like, N6-pyridine-like, and NG-graphite-like nitrogen; NP-pyridine oxide, N-Momolybdenum nitride. The analysis of the obtained results shows that the thickness of the nickel catalytic layer has a significant effect on the concentration of molybdenum nitride in Mo lower electrodes. ...
... The result of deconvoluting the high-resolution spectra of the overlapping of photoemission lines for N1s and Mo3p3/2 indicates the presence of components corresponding to the compounds MoN, MoO2, MoOx, and MoO3 (Table 4), which agrees with the results obtained in Figure 4a,b. 228.95 [43] 229.4 [44] 231.90 [45] 232.70 [46] 399.80 [47] 398.80 [47] 401.50 [47] 402.3 [47] 397.05 [43] * N5-pyrrole-like, N6-pyridine-like, and NG-graphite-like nitrogen; NP-pyridine oxide, N-Momolybdenum nitride. The analysis of the obtained results shows that the thickness of the nickel catalytic layer has a significant effect on the concentration of molybdenum nitride in Mo lower electrodes. ...
... The result of deconvoluting the high-resolution spectra of the overlapping of photoemission lines for N1s and Mo3p3/2 indicates the presence of components corresponding to the compounds MoN, MoO2, MoOx, and MoO3 (Table 4), which agrees with the results obtained in Figure 4a,b. 228.95 [43] 229.4 [44] 231.90 [45] 232.70 [46] 399.80 [47] 398.80 [47] 401.50 [47] 402.3 [47] 397.05 [43] * N5-pyrrole-like, N6-pyridine-like, and NG-graphite-like nitrogen; NP-pyridine oxide, N-Momolybdenum nitride. The analysis of the obtained results shows that the thickness of the nickel catalytic layer has a significant effect on the concentration of molybdenum nitride in Mo lower electrodes. ...
The chemical composition and stoichiometry of vertically aligned arrays of nitrogen- doped multi-walled carbon nanotubes (N-CNTs) were studied by photoelectron spectroscopy using laboratory and synchrotron X-ray sources. We performed careful deconvolution of high-resolution core-level spectra to quantify pyridine/pyrrole-like defects in N-CNTs, which are a key factor in the efficiency of the piezoelectric response for this material. It is shown that the XPS method makes it possible to estimate the concentration and type of nitrogen incorporation (qualitatively and quantitatively) in the "N-CNT/Mo electrode" system using both synchrotron and laboratory sources. The obtained results allow us to study the effect of the nickel catalytic layer thickness on the concentration of pyridine/pyrrole-like nitrogen and piezoelectric response in the nanotubes.
... Due to the presence of N atoms, the reaction centers at adjacent C atoms in functionalized C-N bonds can be activated for additional post reactions. In addition to changing the carrier density, the presence of N atoms in the graphene structure also provides interesting catalytic activity on its surface [15]. NG can be obtained by direct synthesis and postprocessing [16,17]. ...
Nitrogen doping is an effective way to improve the electrical and catalytic properties of graphene. Here, we used a non-thermal plasma technique with AC rotating arc to prepare nitrogen-doped graphene. This method does not need catalyst and can produce nitrogen-doped graphene in the atmospheric environment by large scale. CH4 as the carbon source and N2 as the nitrogen source, nitrogen-doped graphene was obtained by plasma direct synthesis. The nitrogen content in the product was analyzed by X-ray photoelectron spectroscopy and the doping level was about 1.19 at.%. It was found that H2 and CO2 as carrier gases can change the nitrogen doping type and content. When there was only N2, pyrrolic N and graphitic N were the main forms in the graphene. The addition of H2 improved the selectivity of pyridinic N and pyrrolic N, but decreased the nitrogen doping content. CO2 significantly increased the selectivity of pyrrolic N and increased the nitrogen doping content. In addition, the formation mechanism of nitrogen-doped graphene was briefly described in this paper. The key in this plasma production technology is to understand the effect of carrier gas on nitrogen doping, which is also instructive for mass production in industry.
... In nitrogen-doped graphene, depending on the doping procedure, the nitrogen moieties include graphitic N together with pyrrolic and pyridinic nitrogen and amino groups [37][38][39]. Bianco et al. reported recently that pyridine nitrogen can be a reactive center and activates other reactive centers at the adjacent carbon atoms in functionalized C-N bonds for additional post reactions such as oxidations [40]. Obtained FTIR and EDS results indicate that in the CQDs synthesized from o-phenylenediamine, NH 2 groups are dominantly bonded to the basal plane and the edges of the CQDs whereas pyrrolic and pyridinic nitrogen play only a minor role. ...
... But CQDs prepared from o-phenylenediamine do not generate singlet oxygen or OH radicals through energy or electron transfer, because the condensation process of these dots includes NH 2 groups in their structure whereas the presence of pyrrolic and pyridinic nitrogen is really minor. Thus reaction centers for ROS generation (dominantly pyridinic N) do not exist in o-phenylenediamine CQDs [40]. ...
Carbon quantum dots as a novel type of carbon nanomaterials have attracted the attention of many researchers because of their unique optical, antibacterial, and anticancer properties as well as their biocompatibility. In this study, for the first time, carbon quantum dots were prepared from o -phenylenediamine dissolved in toluene by a solvothermal route. Subsequently, the prepared carbon quantum dots were encapsulated into polyurethane films by a swelling–encapsulation–shrink method. Analyses of the results obtained by different characterization methods (AFM, TEM, EDS, FTIR, photoluminescence, and EPR) indicate the significant influence of the precursor on structural, chemical, and optical properties. Antibacterial and cytotoxicity tests showed that these dots did not have any antibacterial potential, because of the low extent of reactive oxygen species production, and showed low dark cytotoxicity. By investigating the cellular uptake, it was established that these dots penetrated the HeLa cells and could be used as probes for bioimaging.
... When doped with nitrogen, depending on the doping procedure, the nitrogen moieties may include graphitic-N along with pyrrolic and pyridinic nitrogen. Among these bonding configurations, graphitic-N induces an n-type doping effect, whereas pyrrolic-N and pyridinic-N may result in either weak n-type or p-type doping [83]; however, among all the possible nitrogen-doping configurations, the graphitic N doping could preserve the high carrier mobility due to minor distortion of the graphene lattice [84]. Moreover, it was also reported that N doping resulted in a shift of the conduction band to the fermi level, increasing the electrical conductivity of the material [85]. ...
Biomass-derived carbons are emerging materials with a wide range of catalytic properties, such as large surface area and porosity, which make them ideal candidates to be used as heterogeneous catalysts and catalytic supports. Their unique physical and chemical properties, such as their tunable surface, chemical inertness, and hydrophobicity, along with being environmentally friendly and cost effective, give them an edge over other catalysts. The biomass-derived carbon materials are compatible with a wide range of reactions including organic transformations, electrocatalytic reactions, and photocatalytic reactions. This review discusses the uses of materials produced from biomass in the realm of heterogeneous catalysis, highlighting the different types of carbon materials derived from biomass that are potential catalysts, and the importance and unique properties of heterogeneous catalysts with different preparation methods are summarized. Furthermore, this review article presents the relevant work carried out in recent years where unique biomass-derived materials are used as heterogeneous catalysts and their contribution to the field of catalysis. The challenges and potential prospects of heterogeneous catalysis are also discussed.
... Graphene edges are more reactive than the planar surface (Shenoy et al., 2008;Syama and Mohanan, 2019;Centi and Perathoner, 2022), and then oxidation processes should mostly occur along these regions. It is well known that because of oxidative reactions of graphene, hydroxyl, carboxyl, carbonyl, peroxide, and epoxide groups are generated giving hydrophilic graphene oxides (Marcano et al., 2010;Zhu et al., 2010;Nezakati et al., 2014;Wazir and Kundi, 2016;Abid et al., 2018;Banerjee, 1918;Bianco et al., 2022). Most oxidative changes are represented in the He-Klinowski-Forster-Lerf model of graphene oxide structure (He et al., 1998;Zhu et al., 2010). ...
... However, the curvature by hydrogenation has the disadvantage of generating saturated sp 3 C atoms, which decreases aromatic conjugation and could modify electronic properties, whereas conjugation is retained in curved graphene sheets by oxidation. Formation of pentagonal pyrrole ring is also possible (Bianco et al., 2022), and results in graphene curvature ( Figure 11). It must be noted that regarding graphene spirals, curvatures not only affecting the A or Z edges are possible, but also a curvature along both edges can occur simultaneously (Braga et al., 2004;Zhu and Li, 2013). ...
“Advances in Biology” presents original research results on the leading edge of medicine and biology research. Each article has been carefully selected in an attempt to present substantial research results across a broad spectrum.
Cytochrome c oxidase (CcO) is the terminal enzyme in the respiratory electron transport chain of aerobic organisms. It is a redox-driven proton pump that converts atmospheric oxygen to water and couples the oxygen reduction, generating a membrane proton gradient that subsequently drives ATP synthesis. The function of CcO as a biomolecular nanomachine that transforms the energy of redox reaction into protonmotive force across a biological membrane has been the subject of intense research, debate, and controversy. For a long time, the molecular mechanism of electron transfer coupled to proton pumping in CcO has been one of the central unsolved problems in biochemistry, molecular biology, and bioenergetics. The enzyme structure has been solved for several organisms; however, details of its molecular mechanism of proton pumping still remain elusive. Mainly, the nature and position of the proton-loading site, a key element of the mechanism, are under dispute. However, nowadays, many essential details and principles have emerged with the accelerating progress in this field. Recent calculations indicate that one of the histidine ligands of the CuB center, His291, may play the role of the pumping element. In this chapter, we review the first principles calculation used to study models of the catalytic center of CcO and calculate the pKa of the His291 residue for both the reduced and oxidized states of the enzyme catalytic center. The combined density functional theory (DFT) and continuum electrostatic calculations (QM/CE method) are employed to explore the coupling of the conformational changes of Glu242 residue, the primary proton donor of both chemical and pump protons, to its pKa, and the pKa of His291, a putative proton-loading site of the pumping model. The pKa values of His291 and Glu242, the two crucial residues of the model, are calculated for different redox states of the enzyme, and the influence of various factors on the pKas is analyzed in detail. To understand how different factors affect the apparent pKa values of His291 and Glu242, we have considered several computational QM/CE models of the membrane‒enzyme‒cavities‒solvent system and tested different dielectric properties of the water-filled cavities. In addition, the DFT is applied to two different sizes of quantum-mechanical (QM) systems of interest. We also review the structure and function of CcO, describe the proposed mechanism of proton pumping, identify the fundamental problems that can be addressed computationally in this area and describe the methods for their solution. The outstanding theoretical and computational challenges of the area are also discussed.
© 2023 Nova Sience Publishers, Inc.
Keywords: bioenergetics, heme-copper oxidases, nitric-oxide reductase, copper center, heme, binuclear complex, histidine ligand, bovine, proton pumping, molecular mechanism, redox-coupled pKa, pKa calculations, DFT, reaction and protein field.
Categories: 2022, Advances in Biology (Numbered Series) *** New in 2022 ***, Biology, Biology Books, Life Sciences, Newly Published Books, Nova, Science and Technology
... This interface between MP-MoS 2 and N-doped rGO, provided by nucleation of amorphous core particles on the defect sites of the N-doped rGO, was observed in the HRTEM images (Fig. 2). N-dopant plays a crucial role in enhancing the conductivity and subsequent electrochemical performance of the NGM nanocomposite [41,42]. Further, the distortion of the crystal lattice of the 1T/2H MoS 2 nanosheets provides high-energy sites for electrochemical reactions. ...
Mixed-phase (MP) metal disulfides have interesting electrochemical properties which originate from the generation of the abundance of electrochemically active sites and a higher structural stability as compared with crystalline materials. However, there is less exploration in the design and performance of the MP materials for supercapacitors application. Herein, nitrogen-doped reduced graphene oxide (N-rGO) with MP molybdenum disulfide (MoS2) nanoflower (NGM) nanocomposite was self-assembled in a one-pot hydrothermal synthesis. The NGM nanocomposites featured a high surface area and electrical conductivity governed by the uniform growth of nanoflowers on the conductive N-rGO sheets. Coupled with an interconnected network of charge transport channels, the robust ion transport and lowered charge transfer resistance at the electrode-electrolyte interphase significantly boost the electrochemical activity enabling the electrodes to deliver a high specific capacitance (539.5 F g⁻¹), exceptional energy and power densities (Pmax = 25.4 kW kg⁻¹, and Emax = 71.5 Wh kg⁻¹) and excellent capacitance retention of 95.3 % during long-term cycling.
... Surface charge is one of the important parameters that affects antibacterial activity as well. Bing et al. reported the antibacterial activity of three types of CQDs with different surface charges [67]. The obtained results showed the following: positively charged CQDs electrostatically interacted with negatively charged E. coli and disrupted the bacterial membrane; negatively charged CQDs had a weaker bactericidal effect on E. coli compared to positively charged CQDs, whereas the uncharged CQDs did not have any antibacterial activity against E. coli and B. suptilis. ...
Development of new types of antimicrobial coatings is of utmost importance due to increasing problems with pathogen transmission from various infectious surfaces to human beings. In this study, new types of highly potent antimicrobial polyurethane composite films encapsulated by hydrophobic riboflavin-based carbon polymer dots are presented. Detailed structural, optical, antimicrobial, and cytotoxic investigations of these composites were conducted. Low-power blue light triggered the composites to eradicate Escherichia coli in 30 min, whereas the same effect toward Staphylococcus aureus was reached after 60 min. These composites also show low toxicity against MRC-5 cells. In this way, RF-CPD composites can be used for sterilization of highly touched objects in the healthcare industry.
... The electron cloud surrounding graphene in the immediate region alters when nitrogen and boron are introduced. Furthermore, this increases the activity of these areas [197]. Similar to substitutional impurities, boron and nitrogen atoms have their own distinct features that affect graphene's properties. ...
Wearable sensors and invasive devices have been studied extensively in recent years as the demand for real-time human healthcare applications and seamless human-machine interaction has risen exponentially. An explosion in sensor research throughout the globe has been ignited by the unique features such as thermal, electrical, and mechanical properties of graphene. This includes wearable sensors and implants, which can detect a wide range of data, including body temperature, pulse oxygenation, blood pressure, glucose, and the other analytes present in sweat. Graphene-based sensors for real-time human health monitoring are also being developed. This review is a comprehensive discussion about the properties of graphene, routes to its synthesis, derivatives of graphene, etc. Moreover, the basic features of a biosensor along with the chemistry of sweat are also discussed in detail. The review mainly focusses on the graphene and its derivative based wearable sensors for the detection of analytes in sweat. Graphene-based sensors for health monitoring will be examined and explained in this study as an overview of the most current innovations in sensor designs, sensing processes, technological advancements, sensor system components, and potential hurdles. The future holds great opportunities for the development of efficient and advanced graphene-based sensors for the detection of analytes in sweat.
