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In recent years, there has been a growing interest in advanced packaging films made from natural polymers. These films are integrated with pH-sensitive dyes, aiming to monitor the freshness of food. Specifically, the development of pH-adaptive intelligent packaging films, known as MC5/ZA5-Anth3%, involves using methylcellulose (MC) and zinc alginate (ZA) as the foundational materials, with anthocyanins (Anth) serving as the freshness indicators. The production of MC5/ZA5-Anth3% films has resulted in improved thermal stability, mechanical properties and water resistance, alongside a reduction in the transmission of ultraviolet–visible (UV–vis) light through the material. Importantly, these color-changing films undergo a noticeable change in color when subjected to pH changes or exposure to ammonia gas, making them suitable for detecting shifts in the pH of foods like pork and shrimp, the presence of volatile nitrogen compounds, and early signs of food degradation. Upon exposure to varying pH buffers, the color indicator film underwent a noticeable transition from a reddish-pink hue to blue, ultimately shifting to blue-green. Consequently, this pH-sensitive color indicator film emerges as a viable candidate for the smart, real-time monitoring of freshness in perishable foods such as pork and shrimp. [ABSTRACT FROM AUTHOR]

Nitrification is a vital process in the biological removal of inorganic nitrogen compounds. In order to ensure the stability and effectiveness of this process, buffer solutions should be added to the system to maintain neutral to slightly alkaline conditions. With a focus on the newly discovered comammox Nitrospira, this research investigates the transition of the nitrifying community within a biofilm reactor under different acidic levels (initiated at pH 6 and gradually decreased to pH 5). During the 305-day continuous operation experiment, it was observed that responsible ammonia oxidizers transitioned from ammonia-oxidizing bacteria (AOB) during the initial stages (setup stage and early stage of pH 6) to comammox Nitrospira under pH 5.5 and pH 5. Further analysis using next-generation sequencing targeting both the 16S rRNA region and amoA region revealed a shift in the dominant cluster of both Nitrospirae and comammox Nitrospira under varying pH conditions. Our study identified a distinct cluster of comammox Nitrospira that is phylogenetically closed to sequences found in acidic environments, but exhibits dissimilarity from known comammox Nitrospira isolates and the majority of environmental sequences. This cluster was found to be prevalent in the acidic biofilm reactor studied and thrived particularly well at pH 5. These findings underscore the potential significance of this distinct, uncultivated group of comammox Nitrospira in performing ammonia oxidation under acidic conditions. Key points: • Ammonia was effectively removed under pH 5.5 and 5 in the biofilm reactor • The dominant ammonia oxidizer was comammox Nitrospira when pH was 5.5 and 5 • A potential acidophilic cluster of comammox Nitrospira was identified in this acidic biofilm reactor [ABSTRACT FROM AUTHOR]

As a result of its high reactivity, furan-2(3H)-one derivative 2 can be selected as a versatile and suitable candidate for building of novel nitrogen heterocyclic compounds. Consequently, furan-2(3H)-one derivative 2 and some nitrogen nucleophiles were utilized as starting materials for the formation of new pyridazinone and pyrrolone derivatives bearing naphthalene moiety. The continuous buildup of insecticide resistance is the main obstacle facing pest control measures. Pyrrole-based insecticides are a favourable choice due to their unique mode of action and no cross-resistance with traditional neurotoxic insecticides. The larvicidal activities of pyrrolone derivatives were assessed against field and laboratory strains of Culex pipiens larvae in comparison with chlorfenapyr (pyrrole insecticide). Compounds 17 (21.05 µg/mL) > 9 (22.81 µg/mL) > 15 (24.39 µg/mL) > 10 (26.76 µg/mL) > 16 (32.09 µg/mL) were most effective against lab strain of C. pipiens larvae relative to chlorfenapyr (25.43 µg/mL). While in field strain, 17 and 15 were the most toxic compounds followed by 9 > 10 > 16 > 2 with LC50 of 9.87, 10.76, 11.52, 12.68, 15.32 and 18.37 µg/mL, respectively, compared with chlorfenapyr with 14.03 µg/mL. The cytochrome P-450 monooxygenase activities were significantly increased in treated larvae of lab and field strains relative to untreated. The great variations in toxicity of the synthesized compounds were interpreted by structure-activity relationship study. The pyrrolone derivatives are effective against field and insecticide-resistant strains. Therefore, they are considered promising compounds to be integrated into pest management programs. [ABSTRACT FROM AUTHOR]

The goal of this research was to assess the efficiency of the liquid digestate treatment conducted with algal, environmental isolates illuminated entirely with sunlight. The photobioreactor was exposed to natural conditions and evaluated based on the reduction of chemical oxygen demand (COD), nitrogen compounds, and soluble phosphates. Microalgal and bacterial communities growing during the treatment process were studied. A high removal rate of soluble COD (= 91%) and nutrients (= 86%) was achieved. The average concentrations of nitrogen, phosphates, and COD in the reactor effluent were 95 mgN/L, 49 mg/L, and 735 mg O2/L, respectively. The overall algae-bacteria biomass productivity of 22 mg/L/d, calculated on the total suspended solids (TSS) basis, was recorded. The microbial analysis revealed the dominance of Tetradesmus obliquus followed by Microglena sp. in the first 14 weeks of the experiment. At the end of the experimental run, Chlorella sorokiniana cells appeared as a result of illumination intensity changes. The dominating bacteria belonged to Firmicutes (26.31%), Patescibacteria (17.38%), and Actinobacteriota (14.86%) and could have been responsible for the transformation of nitrogen and oxidation of organic contaminants. The research demonstrated that natural sunlight can successfully be used for efficient liquid digestate treatment with the algae-bacterial community. [ABSTRACT FROM AUTHOR]

Nitrogen and phosphorous compounds are significant pollutants in urban stormwater runoff. In this study, three lab-scale bioretention cells, namely a control reactor CM, and reactors M1 and M2 containing Scrap Iron Filings (SIF) with granulated brick (M1) and pumice pellets (M2), respectively, were used to evaluate the simultaneous removal of nitrate, nitrite, ammonia, total nitrogen, phosphorous, and COD using simulated runoff. Under unsaturated conditions, M1 with the ZVI-brick combination removed 91.37% TP, while M2 with the ZVI-pumice combination removed 89.76% TP. Under saturated conditions, M2 removed 72.02% TN, and M1 removed 66.1% TN. It was found that the presence of saturation zones benefitted TN removal which can be attributed to the creation of anoxic conditions within saturation zones, which favoured denitrification, as well as the prolongation of influent retention and reaction time, while it hindered TP removal. TP removal percentages for CM, M1, and M2 declined from 86.77%, 91.37%, and 89.76% in unsaturated conditions to 63.99%, 83.67%, and 71.74% in saturated conditions due to the propensity of soil-bound P to leach in anoxic environments. The media amendments were further characterized using Scanning Electron Microscopy (SEM) and X Ray Diffraction analysis (XRD), as well as adsorption and leaching tests. Significantly, the highest pollutant leaching was observed in the assessed conditions for CM, underscoring the usefulness of including media like ZVI, brick powder, and pumice pellets. This incorporation not only heightened the effectiveness of pollutant removal but also fortified their retention in potential future stormwater events. In consideration of this, M1 emerged as the preferred design option, as its non-leaching characteristics were verified through flushing with distilled water after post-stormwater influent loading cycles when compared to traditional designs. [ABSTRACT FROM AUTHOR]

Molecular structure-editing through nitrogen insertion offers more efficient and ingenious pathways for the synthesis of nitrogen-containing compounds, which could benefit the development of synthetic chemistry, pharmaceutical research, and materials science. Substituted amines, especially nitrogen-containing alkyl heterocyclic compounds, are widely found in nature products and drugs. Generally, accessing these compounds requires multiple steps, which could result in low efficiency. In this work, a molecular editing strategy is used to realize the synthesis of nitrogen-containing compounds using aryl alkanes as starting materials. Using derivatives of O-tosylhydroxylamine as the nitrogen source, this method enables precise nitrogen insertion into the Csp2-Csp3 bond of aryl alkanes. Notably, further synthetic applications demonstrate that this method could be used to prepare bioactive molecules with good efficiency and modify the molecular skeleton of drugs. Furthermore, a plausible reaction mechanism involving the transformation of carbocation and imine intermediates has been proposed based on the results of control experiments. Substituted amines, especially nitrogen containing alkyl heterocyclic compounds, are widely found in nature products and drugs, but generally accessing these compounds requires multiple steps. Herein, the authors report a molecular editing strategy for the synthesis of nitrogen-containing compounds using aryl alkanes as starting materials. [ABSTRACT FROM AUTHOR]

Organosilicon compounds play a crucial role as essential building blocks and valuable organic molecules in various materials. They are extensively utilized as synthetic intermediates in chemical synthesis processes. Recent studies have highlighted the multifaceted role of silicon compounds, showcasing their significance not only as reactive participants or products but also as potent catalysts in various chemical reactions, as reported by researchers. In this comprehensive review, our objective is to provide a summary of recent advancements in synthesizing various organosilicon compounds in formation of silicon–carbon, silicon–oxygen, silicon–nitrogen and explore the applications of siliconic materials as catalysts in polymerization, reduction, and isomerization processes. Emphasizing the significant potential of this methodology, we aspire to inspire further research and applications in this rapidly emerging field. Furthermore, this review covers over 50 years of research on organosilicon chemistry in CCERCI under supervision of Prof. Seyed Mohammad Bolourtchian. [ABSTRACT FROM AUTHOR]

Context: In order to synthesize InN nanoparticles (NPs), we have simulated the co-implantation of indium (In) and nitrogen (N) ions on silicon (Si) and silicon oxide (SiO2) substrates with flat-top profiles. The choice of flat-top profile is to increase the possibility of creating homogeneous zone with well-distributed InN nanoparticles over the entire implanted layer. In this view and to obtain these flat-top profiles, we must do several implantations with different doses and energies optimized by our program. The simulation results performed on a silicon substrate < 111 > , give an average dose of 4.30 × 1016 at./cm2 and the implantation energies were In (10, 46, and 180 keV) and N (13 and 35 keV). But for the SiO2 substrate, the total mean dose is about 5.20 × 1016at./cm2 for each Indium and nitrogen ion. The respective implantation energies were In (23, 63, and 120 keV) and N (12 and 28 keV) in an average depth of approximately 100 nm. The implantations were performed in a 206-nm-thick (SiO2) layer thermally grown on < 100 > silicon. Subsequent thermal treatments (500–900 °C) lead to the formation of nanoparticles precipitates of the compound semiconductor (InN) and to cure the oxide defects during different periods of time. To verify that indium (In) and nitrogen (N) ions were located according to flat curves, we used RBS technical and study the formation (InN) stoichiometric compound several techniques, were used such as X-ray diffraction, UV–visible-IR, and photoluminescence (PL) spectroscopy. Methods: The simulated profiles have been chosen with the aim that the implanted element not exceeding 5–10 at %maximum concentration for each species. We have elaborated our program to simulate these profiles using data as input values from SRIM2008 code taking into account the sputtering factor. The optimal conditions are determined, which are the expected depth impact energies (Rp), the standard deviation (ΔRp) and the sputtering corrosion factor (Fs). Through these results, a simulation program has been created which allows building flat "distribution" curves for ion implantation for each element (In and N), so that each curve is obtained from three Gaussian functions whose values are carefully chosen in relation to the optimal experimental conditions. [ABSTRACT FROM AUTHOR]

The hydrothermal liquefaction (HTL) of composite household waste (CHW) was investigated at different temperatures in the range of 240–360 °C, residence times in the range of 30–90 min, and co-solvent ratios of 2–8 ml/g, by utilising ethanol, glycerol, and produced aqueous phase as liquefaction solvents. Maximum biocrude yield of 46.19% was obtained at 340 °C and 75 min, with aqueous phase recirculation ratio (RR) of 5 ml/g. The chemical solvents such as glycerol and ethanol yielded a biocrude percentage of 45.18% and 42.16% at a ratio of 6 ml/g and 8 ml/g, respectively, for 340 °C and 75 min. The usage of co-solvents as hydrothermal medium increased the biocrude yield by 35.30% and decreased the formation of solid residue and gaseous products by 19.82% and 18.74% respectively. Also, the solid residue and biocrude obtained from co-solvent HTL possessed higher carbon and hydrogen content, thus having a H/C ratio and HHV that is 1.01 and 1.23 times higher than that of water as hydrothermal medium. Among the co-solvents, HTL with aqueous phase recirculation resulted in higher carbon and energy recovery percentages of 9.36% and 9.78% for solid residue and 52.09% and 56.75% for biocrude respectively. Further qualitatively, co-solvent HTL in the presence of obtained aqueous phase yielded 33.43% higher fraction of hydrocarbons than the pure water HTL and 7.70–17.01% higher hydrocarbons when compared with ethanol and glycerol HTL respectively. Nitrogen containing compounds, such as phenols and furfurals, for biocrudes obtained from all HTL processes, were found to be present in the range of 8.30–14.40%. [ABSTRACT FROM AUTHOR]

This work studies the impact of foliar application of methyl jasmonate (MeJA) and methyl jasmonate plus urea (MeJA + Ur) on the evolution of amino acid content in 'Tempranillo' grapes during ripening, across two vintages. To achieve this goal, sample grapes were harvested at five different timing. Fol1: 1 day before first foliar application; Fol2: 1 day before second foliar application; Preharvest: 15 days after second foliar application; Harvest: the day of harvest; and Postharvest: 15 days after harvest. The effect of foliar treatments was season dependent, being effective to improve the amino acids content of grapes only in the first vintage. Among the treatments studied, foliar application of MeJA-Ur showed better results. The evolution of amino acids during ripening also was different among seasons. Overall, in the 2019, amino acids reached their highest content at Preharvest or Harvest samples, whereas in the 2020 season, these highest concentrations were reached at Postharvest. Asparagine might serve as a suitable amino acid for controlling grape ripening, as its content decreased from Fol1 to Postharvest in the two vintages. Moreover, differences on the total amino acids content at Harvest date between vintages were observed, probably due to different climatological conditions. Therefore, this study pioneers the examination of the impact of foliar applications of MeJA and MeJA + Ur on the amino acids evolution in 'Tempranillo' grapes during ripening. The need for further research is clear to comprehend the complex interaction between foliar treatments and grape amino acids dynamics for optimizing nitrogen quality of grapes. [ABSTRACT FROM AUTHOR]

Reaction of 4,6-dinitroresorcinol (1) and the nitrogen base 1,4-diazabicyclo[2·2·2]octane (2) affords the 1:2 salt and proton-transfer compound 1,4-diazabicyclo[2·2·2]octane-1,4-diium bis(5-hydroxy-2,4-dinitrophenolate) (3). Compound 3 crystallizes in the triclinic crystal system (space group P-1) with a = 8.3242(5) Å, b = 11.9915(7) Å, c = 12.4595(7) Å, α = 116.282(2)°, β = 100.576(3)°, γ = 101.051(2)°, 1042.30(11) Å3 and Z = 2. The dication 2- H 2 2 + forms charge assisted donating bifurcated N+−H⋅⋅⋅O− hydrogen bonds to the phenolate moieties of two monoanions of 1. The latter exhibit an intramolecular O−H⋅⋅⋅O hydrogen bond between the hydroxy group and the nitro group in ortho position. The crystal structure of 3 features pseudo B-centering of the lattice, which relates the two crystallographically distinct monoanions of 1 by a pseudo translation. The possible B-centring is broken by the ethylene groups of 2-H22+, which are related in neighbouring molecules by centres of symmetry. [ABSTRACT FROM AUTHOR]

The nanoporous compound SBA-15 was functionalized using (3-aminopropyl)trimethoxysilane (APTES). Then the obtained product was modified with ellagic acid (ELA), a bioactive polyphenolic compound. The structure of the prepared nanoporous composition SBA-15@ELA was extensively characterized and confirmed by various techniques, such as Fourier-transform infrared (FT-IR) spectroscopy, Energy dispersive X-ray (EDX) elemental analysis, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM) and N2 adsorption–desorption isotherms (BET). The novel, recoverable, heterogenous SBA-15@ELA nanoporous compound was used to investigate its catalytic effect in the synthesis of 4-oxo-quinazoline derivatives (19 examples) with high yields (78–96%), as an important class of nitrogen-containing heterocyclic compounds. The use of an inexpensive mesoporous catalyst with a high surface area, along with easy recovery by simple filtration are among the advantages of this catalysis research work. The catalyst has been used in at least 6 consecutive runs without a significant loss of its activity. [ABSTRACT FROM AUTHOR]

For two years, the contribution of fungi and bacteria to the process of net ammonification in soddy-podzolic soil of the sorrel–blueberry birch forest of Yaroslavl oblast was determined using inhibitory analysis. It was established that the litter is characterized by equal participation of fungi and bacteria in this process. In the humus horizon, a slight excess of fungi over bacteria was noted in years of normal moisture and there was a clear dominance of fungi in dry years. In the eluvial part of the profile, the close contribution of these groups was noted, with an insignificant prevalence of one of them over the years of study. The maximum air temperature is able to change the seasonal dynamics of the abundance of saprotrophic fungi in the soil and to some extent form the generic structure of the mycobiota in the horizons of the soil profile of the birch forest. [ABSTRACT FROM AUTHOR]

Recovering renewable chemicals from de-fatted microalgal residue derived from lipid extraction within the algal-derived biofuel sector is crucial, given the rising significance of microalgal-derived biodiesel as a potential substitute for petroleum-based liquid fuels. As a circular economy strategy, effective valorization of de-fatted biomass significantly improves the energetic and economic facets of establishing a sustainable algal-derived biofuel industry. In this scenario, this study investigates flash catalytic pyrolysis as a sustainable pathway for valorizing Scenedesmus sp. post-extraction residue (SPR), potentially yielding a bio-oil enriched with upgraded characteristics, especially renewable aromatic hydrocarbons. In the scope of this study, volatile products from catalytic and non-catalytic flash pyrolysis were characterized using a micro-furnace type temperature programmable pyrolyzer coupled with gas chromatographic separation and mass spectrometry detection (Py–GC/MS). Flash pyrolysis of SPR resulted in volatile products with elevated oxygen and nitrogen compounds with concentrations of 46.4% and 26.4%, respectively. In contrast, flash pyrolysis of lyophilized microalgal biomass resulted in lower concentrations of these compounds, with 40.9% oxygen and 17.3% nitrogen. Upgrading volatile pyrolysis products from SPR led to volatile products comprised of only hydrocarbons, while completely removing oxygen and nitrogen-containing compounds. This was achieved by utilizing a low-cost HZSM-5 catalyst within a catalytic bed at 500 °C. Catalytic experiments also indicate the potential conversion of SPR into a bio-oil rich in monocyclic aromatic hydrocarbons, primarily BETX, with toluene comprising over one-third of its composition, thus presenting a sustainable pathway for producing an aromatic hydrocarbon-rich bio-oil derived from SPR. Another significant finding was that 97.8% of the hydrocarbon fraction fell within the gasoline range (C5–C12), and 35.5% fell within the jet fuel range (C8–C16). Thus, flash catalytic pyrolysis of SPR exhibits significant promise for application in drop-in biofuel production, including green gasoline and bio-jet fuel, aligning with the principles of the circular economy, green chemistry, and bio-refinery. [ABSTRACT FROM AUTHOR]

The review concerns methods for modeling the crystal structure of polynitrogen compounds and their cocrystals. The state of the art in chemical research into (co)crystals of energetic compounds is described. Various structure modeling methods (including original ones) are considered and analyzed, and criteria for cocrystal formation at different co-former ratios are proposed. The results are discussed of studies on the search for crystal packings of various polynitrogen compounds and their cocrystals, on prediction of the possibility of cocrystal formation, and targeted synthesis of new substances. The predictive power of the developed structure modeling methods is confirmed by the results of X-ray diffraction studies of the synthesized cocrystals. Prospects for application of certain cocrystals as a basis for energetic materials are outlined. [ABSTRACT FROM AUTHOR]

The contribution of fungi and bacteria to the process of net ammonification in the soddy–podzolic soil of the wood sorrel–bilberry birch forest of Yaroslavl oblast has been determined using inhibitory analysis. Representatives of the genera Penicillium Link (70–99%) and Trichoderma Pers. (6–20%) dominate in the mycobiota of saprotrophic fungi. Seasonal changes in the total number of fungi and the content of Corg and Norg in the soil correlate only in the eluvial horizon, with r = (–0.8) and (–0.7). In horizons A0 and A2, total fungal abundance is negatively correlated with nitrogen accumulation, with r = (–0.85) to (–0.89). It has been established that the litter is characterized by an equal participation of fungi and bacteria in this process. In the humus horizon, a slight excess of the participation of fungi over bacteria is noted. In the eluvial part of the profile, the contribution of bacteria is slightly higher than the contribution of fungi. The maximum air temperature is able to regulate the seasonal dynamics of the number of saprotrophic fungi in the soil. [ABSTRACT FROM AUTHOR]

Organic matter in extraterrestrial samples is a complex material that might have played an important role in the delivery of prebiotic molecules to the early Earth. We report here on the identification of nitrogen-containing compounds such as amino acids and N-heterocycles within the recent observed meteorite fall Winchcombe by high-spatial resolution spectroscopy techniques. Although nitrogen contents of Winchcombe organic matter are low (N/C ~ 1–3%), we were able to detect the presence of these compounds using a low-noise direct electron detector. These biologically relevant molecules have therefore been tentatively found within a fresh, minimally processed meteorite sample by high spatial resolution techniques conserving the overall petrographic context. Carbon functional chemistry investigations show that sizes of aromatic domains are small and that abundances of carboxylic functional groups are low. Our observations demonstrate that Winchcombe represents an important addition to the collection of carbonaceous chondrites and still preserves pristine extraterrestrial organic matter. Important biomolecules from the birth of our Solar System such as amino acids and polyaromatic hydrocarbons were analysed in the UK meteorite fall Winchcombe by synchrotron and electron microscopy techniques with unique high energy resolution. [ABSTRACT FROM AUTHOR]

For more than a century, cutting-edge research in organic chemistry has been the discovery of novel, powerful synthetic procedures to create very significant N-heterocyclic scaffolds. Nitrogen-containing heterocyclic scaffolds owing to their extensive abundance in natural products and bioactive compounds has gathered a growing attention in both academical and industrial sectors in pursuit of development of highly efficient clinical targets and drug candidates. Given the significance of nitrogen-rich compounds in contemporary science, significant efforts have been conducted over the past few decades investigating effective techniques for synthesis of N-heterocycles. Due to its intrinsic flexibility and extensive range of applications, catalytic denitrogenative reaction employing transition metal has differentiated itself as a cornerstone among numerous initiatives. In the present article we have outlined the most recent breakthroughs in metal-catalyzed denitrogenative reactions, for proactive synthesis N-heterocycles. [ABSTRACT FROM AUTHOR]

Samples of water and bottom sediments of Lake Ladoga, collected in 2021, were studied to determine the concentrations of mineral and total phosphorus as well as ammonium ions. This study was prompted by the significance of Lake Ladoga as a crucial fisheries resource and a vital water supply source. Additionally, being situated in an economically developed region of Russia, the lake is subject to substantial influences from nearby settlements and enterprises. Throughout the research, samples were taken at 23 stations from two or three horizons, depending on the station's depth. The findings revealed that areas of the lake experiencing intense anthropogenic impact, such as Volkhov Bay, near Priozersk, and the mouth of the Burnaya River, exhibited higher values of the investigated parameters. Furthermore, the study identified a correlation between the hydrological features of the lake and the content of phosphorus and nitrogen compounds, indicating that certain biogens reach the central areas of Lake Ladoga, which are distant from direct anthropogenic influence. The study concluded that, on the whole, phosphorus concentrations in Ladoga's waters are at the mesotrophic level, consistent with recent trends. The concentrations of ammonium nitrogen showed no fundamental changes compared to previous years of observations. The accumulation of phosphorus and nitrogen compounds in soils is influenced by both their concentrations in the overlying water layers and the inherent properties of the soils themselves. [ABSTRACT FROM AUTHOR]

As a result of the study of the concentration levels of pollutants in the waters of the Nalchik River basin under changing climate conditions has provided data on the composition and quality of the water. The studies were carried out in the middle and lower reaches of the river; the results of annual observations, including all seasons of the year, are presented. The seasonal dynamics of the concentrations of ingredients was noted. The changes in the content of six trace elements Cr, Ni, Mn, Zn, Pb, Cu and three nitrogen compounds NO3–, NO2–, NH4+ were compared. The variability of the level of concentrations of microelements and inorganic nitrogen compounds is considered, the main pollutants are identified. [ABSTRACT FROM AUTHOR]

Leaf stacking fermentation involves enzymatic actions of many microorganisms and is an efficient and environmentally benign process for degrading macromolecular organic compounds. We investigated the dynamics of metabolite profiles, bacterial and fungal communities and their interactions during fermentation using cigar leaves from three geographic regions. The results showed that the contents of total sugar, reducing sugar, starch, cellulose, lignin, pectin, polyphenol and protein in cigar tobacco leaves was significantly decreased during fermentation. Notably, the furfural, neophytadiene, pyridine, benzyl alcohol, geranylacetone, 3-hydroxy-2-butanone, N-hexanal, 3-Methyl-1-butanol and 2,3-pentanedione were important features volatile aroma compounds during fermentation. The α-diversity of fungi and bacteria initially increased and then decreased during fermentation. An analysis of variance showed that microbial diversity was influenced by fermentation stages and growing locations, in which the all stages had greater impacts on α- and β-diversity than all regions. Microbiome profiling had identified several core bacteria including Sphingomonas, Bacillus, Staphylococcus, Pseudomonas, Ralstonia, Massilia and Fibrobacter. Fungal biomarkers included Aspergillus, Penicillium, Fusarium, Cladosporium and Trichomonascus. Interestingly, the molecular ecological networks showed that the core taxa had significant correlations with metabolic enzymes and physicochemical properties; bacteria and fungi jointly participated in the carbohydrate and nitrogen compound degrading and volatile aroma compound chemosynthesis processes during fermentation. These studies provide insights into the coupling of material conversion and microbial community succession during leaf fermentation. Key points: Furfural, neophytadiene, pyridine, benzyl alcohol, geranyl acetone, 2-butanone, 3-hydroxy-, N-hexanal, isoamylalcohol and 2,3-pentanedione were important features volatile aroma compounds. The Sphingomonas, Bacillus, Staphylococcus, Pseudomonas, Ralstonia, Massilia, Fibrobacter Aspergillus, Penicillium, Fusarium, Cladosporium and Trichomonascus play an important role in fermentation. The bacteria and fungi jointly participated in the the degradation of carbohydrate and nitrogen compounds in cigar tobacco leaves during fermentation. [ABSTRACT FROM AUTHOR]

The surface color of cigar tobacco leaves (CTLs) is largely determined by the browning response and is one of the most important quality traits affecting consumer preferences. The physiological changes and metabolic network of browning in CTLs after harvest have not been reported. We investigated the molecular mechanism of browning in CTLs by comparing the physiological characteristics and metabolites of CTLs browning at five postharvest periods. Phenotypic traits and browning-related enzyme activity data indicated that the browning reaction was most intense at approximately 12 d when polyphenol oxidase and peroxidase activities reached their maximum. Postharvest CTLs polyphenols, polyacids, and carbon and nitrogen compounds were rapidly degraded during the yellowing phase, and the biosynthesis rate of polyphenols and carotenoids was greater than the degradation rate during the browning phase. Metabolomic analysis discovered 2027 metabolites that were annotated mainly to lipids and lipid-like molecules, organic acids and their derivatives, and organic heterocyclic components. Hierarchical cluster analysis discovered glutamate, serine, threonine, ornithine, and arginine as the major amino acids involved in the browning reaction. KEGG pathway enrichment analysis indicated that the metabolic pathways with important effects on enzymatic browning were phenylpropanoid biosynthesis, flavonoid biosynthesis, isoquinoline alkaloid biosynthesis, phenylalanine metabolism, and linoleic acid metabolism. The metabolic pathway network was mined, and the main polyphenols involved in the browning reaction of CTLs were found to be cyanidin, rutin, caffeoylquinic acid, kaempferol, naringin, and neohesperidin. This study provides a reference for the browning physiology and metabolism network of postharvest CTLs. [ABSTRACT FROM AUTHOR]

Context: This article presents a theoretical study of three insensitive high explosives based on the FOX-7 moiety. A few heterocyclic five- and six-member nitrogen-rich compounds have been created in an effort to better serve as a potential insensitive high explosive. It has been addressed how these molecules should be optimised in terms of stability, sensitivity, detonation properties, IR frequency computations, formal charge calculations, and more. Comprehensive research has been done on these compounds' molecular density and energy of activation associated with the conversion from nitro (C-NO2) to nitrito (C-ONO) during the initial phase of their decomposition. The bond dissociation energy along with BSSE correction for the most reactive C-NO2 bond is examined. The two designed molecules have intra-molecular hydrogen-bonding while other does not have any intra-molecular hydrogen-bonding. The newly designed compounds exhibit higher detonation values compared to TNT, which suggests that they ought to be prepared in a laboratory by skilled experimenters. Methods: The stability of the C-NO2 link and the covalent character of the bonds have both been calculated using the atoms in molecule (AIM) method. The electronic structure calculations have been recovered at DFT method with aug-cc-pVDZ basis set using the Gaussian-16 quantum chemistry programme. [ABSTRACT FROM AUTHOR]

The article presents the results of a study of some adaptive properties of a bacterial isolate from wheat bran, identified by the 16S rRNA gene as an Arthrobacter agilis strain. According to the literature data, A. agilis does not belong to the dominant bacterial species of wheat microbial associations and activates growth at low ambient temperatures. The studied A. agilis strain showed poor growth in a microbial consortium when an aqueous suspension of wheat bran, partially fermented at 28 ± 1°C by the native microbiota, was plated on a dense MPA medium and produced the pigment after three weeks of storage at 4 ± 1°C. Moderate growth of bacteria without increased pigmentation was observed during its subsequent transfer after low-temperature storage on agar media containing carbohydrates and nitrogen compounds, mineral salts, and vitamins that were more easily utilized than native bran. The growth of colonies upon plating on such media increased in the series: thermally fermented wheat bran → HMF agar → LB (without salt). It was revealed that the A. agilis strain, which was not typical of the wheat bran microflora, under the influence of osmotic and/or temperature shock (in response to a sharp change in the NaCl concentration and/or a difference in ambient temperatures) produced pigments both in agar and liquid cultures. According to the results of spectral analysis, the pigment was assigned to carotenoids and tentatively identified as bacterioruberin. Quantitative evaluation showed that, under stress conditions during submerged cultivation, the studied strain A. agilis wb28 was able to synthesize the pigment at the level of 52.8 mg/L (17.2 mg/g biomass). [ABSTRACT FROM AUTHOR]

The combination of nitrogen and phosphorus compounds has synergistic flame retardant effect, but the addition of low phosphorus content compounds is large, which affects the mechanical properties of polymers. Phosphorus ammonium polyphosphate (APP) with high phosphorus content and graphitic carbon nitride (g-C3N4) doped with SiO2 were used for the flame retardant (CN-Si-APP) of polyamide 6 (PA6). CN-Si-APPs with different APP/CN mass ratio (1, 2.5 and 4) and dosage (7 and 12 wt%) were blended with PA6 via a twin-screw extruder, and their flame retardancy was investigated by limiting oxygen index (LOI), UL-94 test, muffle furnace carbonization test and raman spectroscopy. When only APP added, the coefficient of water absorption (CWA) of composites increased and its tensile strength greatly reduced by nearly 37.1% to 35.39 MPa. The addition of g-C3N4 inhibited the water absorption. When the addition dosage is 7%, the CWA of PA6/APP, PA6/CN-Si-APP2.5, PA6 and PA6/CN were 11.1, 6.86, 5.78 and 4.6%, respectively. SiO2 effectively improved the dispersion of g-C3N4 and the mechanical properties of composites. Thermogravimetric analysis (TGA) showed that the char residue of PA6 composites was improved significantly. The composite with 7 wt% CN-Si-APP4 passed the UL-94 V-0 rating. The LOI value and graphitization degree (ID/IG) of PA6/12 wt% CN-Si-APP2.5 reached 28.7% and 2.93 respectively. Under the same dosage, the graphitization degree of CN-Si-APP2.5 (3.51) was higher than that of g-C3N4 (3.98). The barrier protection of g-C3N4, catalytic effect of APP and SiO2 crosslinking network promoted PA6 to form a dense and stable char layer, which protected PA6 composites from the flame. The strategy of synergistic flame retardant in this paper provides a valuable solution for reducing the amount of flame retardant. [ABSTRACT FROM AUTHOR]

This article presents a quantitative structure–activity relationship (QSAR) approach for predicting the acid dissociation constant (pK a ) of nitrogenous compounds, including those within supramolecular complexes based on cucurbiturils. The model combines low-cost quantum mechanical calculations with QSAR methodology and linear regressions to achieve accurate predictions for a broad range of nitrogen-containing compounds. The model was developed using a diverse dataset of 130 nitrogenous compounds and exhibits excellent predictive performance, with a high coefficient of determination (R 2 ) of 0.9905, low standard error (s) of 0.3066, and high Fisher statistic (F) of 2142. The model outperforms existing methods, such as Chemaxon software and previous studies, in terms of accuracy and its ability to handle heterogeneous datasets. External validation on pharmaceutical ingredients, dyes, and supramolecular complexes based on cucurbiturils confirms the reliability of the model. To enhance usability, a script-like tool has been developed, providing a streamlined process for users to access the model. This study represents a significant advancement in pK a prediction, offering valuable insights for drug design and supramolecular system optimization. [ABSTRACT FROM AUTHOR]

Combining the unique advantages of two-dimensional transition metal carbon/nitrogen compounds (MXene) and the excellent surface-enhanced Raman scattering (SERS) performance of noble metal materials, MXene/Ag NPs films were proposed as nanocarriers for SERS-traceable drug delivery. The films were prepared by two-step self-assembly on positively charged silicon wafers using virtue of the high evaporation of ethyl acetate, the Marangoni effect, and an oil/water/oil three-phase system. With 4-mercaptobenzoic acid (4-MBA) as the probe molecule, the SERS detection limit was 10−8 M and had shown a good linear relationship in the range of 10−8–10−3 M. Simultaneously, the film had good uniformity, repeatability, and stability. When Ti3C2Tx/Ag NPs films were used as nanocarriers, the anticancer drug doxorubicin (DOX) was loaded onto the surface through 4-MBA, and the tracking and monitoring were realized by SERS. The addition of glutathione (GSH) triggered the thiol exchange reaction, resulting in the shedding of 4-MBA from the surface of the film, which indirectly achieved the efficient release of DOX. Furthermore, the loading of DOX and the drug release effect triggered by GSH maintained a certain stability in serum, which provided a potential possibility for the subsequent loading and release of drugs by films with three-dimensional structures as scaffolds in biological therapy. Self-assembled MXene/Ag NPs film nanocarriers for SERS-traceable drug delivery and GSH-triggered high-efficiency drug release [ABSTRACT FROM AUTHOR]

Indole and its derivatives are typical nitrogen heterocyclic compounds and have been of immense concern since they are known for the risk of their toxic, recalcitrant, and carcinogenic properties for human, animals and ecological environment. Bacteria play vital role in the degradation and biotransformation of such persistent organic and harmful pollutants. In this experiment, Acinetobacter towneri NTA1-2A and Acinetobacter guillouiae TAT1-6A were used to degrade indole. Indole-degradated metabolites were analyzed by metabolomics analysis of fermentation broth of these strains using LC-MS/MS. The metabolomics analysis showed indole-5-carbonitrile 3-benzoyl (C16H10N2O), dimethyl sulfoxide (C2H6OS), deoxyguanosine (C10H13N5O4), Leu (C6H13NO2), and N-nitroso-pyrrolidine were indole-degradated metabolites formed by A. towneri NTA1-2A while neurine (C5H13NO) and norvaline (C5H11NO2) are common metabolites of both strains. The two strains' degradation metabolites differed from those reported in other studies, demonstrating the diversity of the distinct microbial strains approach to the metabolism of indolic compounds. Extracellular enzymes released to culture medium by these bacteria were also identified. In conclusion, the two bacterial strains have a potential of converting notorious indole compound to non-toxic intermediates mediated by enzymes. Hence, future study should focus on biochemical pathway and genetic basis for indole-degradated metabolites in the two strains. [ABSTRACT FROM AUTHOR]

Methane is a potent greenhouse gas, which likely enabled the evolution of life by keeping the early Earth warm. Here, we demonstrate routes towards abiotic methane and ethane formation under early-earth conditions from methylated sulfur and nitrogen compounds with prebiotic origin. These compounds are demethylated in Fenton reactions governed by ferrous iron and reactive oxygen species (ROS) produced by light and heat in aqueous environments. After the emergence of life, this phenomenon would have greatly intensified in the anoxic Archean by providing methylated sulfur and nitrogen substrates. This ROS-driven Fenton chemistry can occur delocalized from serpentinization across Earth's humid realm and thereby substantially differs from previously suggested methane formation routes that are spatially restricted. Here, we report that Fenton reactions driven by light and heat release methane and ethane and might have shaped the chemical evolution of the atmosphere prior to the origin of life and beyond. Abiotic methane and ethane formation routes in aqueous environments driven by light and heat are identified. The released hydrocarbons may have contributed to the chemical evolution of the atmosphere from prior to the origin of life until today. [ABSTRACT FROM AUTHOR]

Recently nitrogen-hydrogen compounds have successfully been applied as co-catalysts for mild conditions ammonia synthesis. Ca2NH was shown to act as a H2 sink during reaction, with H atoms from its lattice being incorporated into the NH3(g) product. Thus the ionic transport and diffusion properties of the N–H co-catalyst are fundamentally important to understanding and developing such syntheses. Here we show hydride ion conduction in these materials. Two distinct calcium nitride-hydride Ca2NH phases, prepared via different synthetic paths are found to show dramatically different properties. One phase (β) shows fast hydride ionic conduction properties (0.08 S/cm at 600 °C), on a par with the best binary ionic hydrides and 10 times higher than CaH2, whilst the other (α) is 100 times less conductive. An in situ combined analysis techniques reveals that the effective β-phase conducts ions via a vacancy-mediated phenomenon in which the charge carrier concentration is dependent on the ion concentration in the secondary site and by extension the vacancy concentration in the main site. The detailed structures of two calcium nitride-hydride phases (Ca2NH) are explored and connected to their respective ionic conductivity. These materials have previously been investigated as a co-catalysts/support material for ammonia synthesis. [ABSTRACT FROM AUTHOR]

The review analyzes literature data published in the past 8 years on the synthesis of biologically active tetrahydroquinoline derivatives via the Povarov reaction and its three-component modification. [ABSTRACT FROM AUTHOR]

Pyrolysis is one of the most promising methods to treat waste tires. In this paper, a waste rubber model is established, and the pyrolysis process of rubber polymer at 1500–3000 k is investigated by molecular dynamics simulation. The whole pyrolysis process, the pyrolysis behavior of each component and the formation of S and N compounds are studied in detail. The results show that natural rubber (NR), styrene butadiene rubber (SBR) and nitrile rubber (NBR) are in the leading position in the pyrolysis process. When the carbon chain of rubber macromolecule breaks, many C and H atoms escape from it and combine with each other to form CH3, H radicals, CH4, H2, etc.; The pyrolysis products of waste rubber mainly include hydrocarbons CH4, C2H2, C4H2, C5H4, sulfur compounds H2S, CH3SH, HS, nitrogen compounds NH3, HCN and small molecule substances H2; The increase of temperature can promote the pyrolysis of rubber, promote the carbon chain fracture, and promote the formation of more H2S; For H2S formation, HS is an important intermediate. HS compounds are mainly formed through the gradual pyrolysis of thiophene and polysulfide rubber. HS is stabilized by the transfer of H atoms. For nitrogenous pollutants, HCN is an important component in the pyrolysis. With the increase of temperature, the amount of HCN increases because of the decomposition of complex nitrogen compounds. The amount of oxygen has little effect on sulfide and nitride. At high temperature, nitrogen will also participate in the pyrolysis reaction. This paper reveals the pyrolysis behavior of waste rubber and the formation mechanism of S and N pollutants through simulation research, which provides a reference for the further development of waste tire rubber pyrolysis recovery.Article Highlights: The whole pyrolysis process, the pyrolysis behavior of each component and the formation of S and N compounds are studied in detail. The increase of temperature can promote the pyrolysis of rubber, promote the carbon chain fracture, and promote the formation of more H2S. For H2S formation, HS is an important intermediate. HS is stabilized by the transfer of H atoms. For nitrogenous pollutants, HCN is an important component. With the increase of temperature, the amount of HCN increases. [ABSTRACT FROM AUTHOR]

Microbial metabolomics allows understanding and to comprehensively analyse metabolites, and their related cellular and metabolic processes, that are produced and released to the extracellular environment under specific conditions. In that regard, the main objective of this research is to understand the impact of culture media changes in the metabolic profile of Pedobacter lusitanus NL19 (NL19) and Pedobacter himalayensis MTCC 6384 (MTCC6384) and respective influence on the production of biotechnologically relevant compounds. Solid-phase microextraction combined with comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry with time-of-flight analyser (GC × GC-ToFMS) was applied to comprehensively study the metabolites produced by NL19 and MTCC6384 both in tryptic soy broth 100% (TSB100) and tryptic soy broth with 25% casein peptone (PC25). A total of 320 metabolites were putatively identified, which belong to different chemical families: alcohols, aldehydes, esters, ethers, hydrocarbons, ketones, nitrogen compounds, sulphur compounds, monoterpenes, and sesquiterpenes. Metabolites that were statistically different from the control (sterile medium) were selected allowing for the construction of the metabolic profile of both strains. A set of 80 metabolites was tentatively associated to the metabolic pathways such as the metabolism of fatty acids, branched-chain aminoacids, phenylalanine, methionine, aromatic compounds, and monoterpene and sesquiterpene biosynthesis. This study allowed to better understand how slight changes of the culture media and thus the composition of nutrients impair the metabolic profile of bacteria, which may be further explored for metabolomics pipeline construction or biotechnological applications. [ABSTRACT FROM AUTHOR]

In this research, the starting compounds tetrachloromonospirocyclotriphosphazenes, (BzSpiro-5)R1(N3P3)Cl4 [Bz: Benzyl; R1: Me (1) and R1: Et (2)], were synthesized from the reactions of hexachlorocyclotriphosphazene, N3P3Cl6 (HCCP, trimer) with N/N-donor type benzyldiamines. Both phosphazenes were reacted with 9-ethyl-N-methyl-3-carbazolyldiamines (3 and 4) to form dichloro trans/cisN/N-dispirocyclotriphosphazenes, [(BzSpiro-5)R1(N3P3)(CzSpiro-n)R2]Cl2 (Cz: Carbazolyl; R1, R2: Me or Et; n = 5 or 6; (5a–8a and 5b–8b), containing unsymmetrical diamino precursors. The structure of the cis-5b was clarified by single-crystal X-ray crystallography. The space group of the chiral cis-5b isomer is P−1, which is centrosymmetric, and both enantiomers must be present in the unit cell. Since the absolute configuration of an enantiomer is found as SR′ according to the X-ray crystallography, the other must be RS′. The chiralities of the compounds were also confirmed by 31P NMR spectroscopy recorded upon the addition of chiral solvating agent [(S)-(+)-2,2,2-trifluoro-1-(9′-anthryl)ethanol; CSA] (for 5a, 5b and 8b) and the circular dichroism (CD) (for 5a, 5b, 6a and 6b) spectra. All N/N-dispirocyclotriphosphazenes (5a–8b) bearing carbazole units exhibited a fluorescence profile with a lifetime of about 4.9–6.5 ns and a quantum yield in the range of 0.11–0.20. On the other hand, P. aeruginosa was sensitive to compounds 5b, 7a, 8a and 8b, while E. coli was sensitive to most of the phosphazenes. The cytotoxic activities of phosphazenes against Vero cells (healthy) and MDA-MB-231 breast cancer cells were determined. In addition, compounds 5a and 5b appear to have very high antioxidant activity with respect to radical scavenging activities of 55.1% and 68.3%, respectively. [ABSTRACT FROM AUTHOR]

To evaluate the effect of chemical structure on flame-retardant mechanisms, two types of flame retardants (FRs) containing both phosphorus and nitrogen groups such as N-(2-methoxyethyl)-N-methyl-P,P-diphenylphosphinic amide (PNOFR) and 2-(dimethylamino)ethyl diphenylphosphinate (PONFR) were synthesized and applied to polyvinyl chloride (PVC). PNOFR and PONFR exhibited the typical flame-retardant mechanism of FRs containing phosphorus and nitrogen compounds. It was observed that PNOFR and PONFR have different main flame-retardant mechanisms depending on the element combined with phosphorus in their chemical structures. In the condensed phase, PNOFR induced a denser crosslinked char layer with a higher phosphorus content compared with PONFR. By contrast, in the gas phase, PONFR released more PO2∙ and PO∙ radicals compared with PNOFR. Therefore, while PNOFR and PONFR have flame-retardant properties through both mechanisms, the dominant mechanisms for PNOFR and PONFR are different. This study presents an effective strategy for designing attractive chemical structures to prepare FRs for applications in various polymers. [ABSTRACT FROM AUTHOR]

State-of-the-art in the field of recovering high-molecular-mass hydrocarbon components of bituminous and shale rocks by intrastratum transformation into readily recoverable forms using sub- and supercritical water is analyzed. The phase composition of water and its properties in the critical state and the transformations of a number of substances in subcritical (SBW) and supercritical (SCW) water are discussed. The substances under consideration include model polycyclic and heteroatomic compounds containing nitrogen, sulfur, and oxygen, metal porphyrin complexes, asphaltenes, oil sands, and heavy oils and organic matter (OM) of kerogen-containing shale rocks. The preventing effect of hydrogen donors and catalysts for hydrogenation and oxidative cracking on the coking in the course of transformation of heavy hydrocarbons in SCW is compared. The catalytic effect of the mineral matrix of rocks in the course of generation of oil fractions from them is analyzed in detail. The published data concerning the possibility of using SBW and SCW for the transformation of high-molecular-mass components of high-carbon dense rocks from unconventional formations demonstrate high potential of hydrothermal and supercritical fluid technologies. [ABSTRACT FROM AUTHOR]

Colorimetric food freshness indicators (CFFIs) are important in food packaging for monitoring the quality of food products during storage and transportation. CFFIs can supplement the conventional "best before date" embedded in food product packages by providing real-time and naked-eye quality information to the stakeholders, thereby ensuring product safety and preventing food waste. Various cellulosic materials have been employed as the matrix/carrier in CFFIs. In addition to their transparency, nontoxicity, high water/dye absorption capacity, unique film-forming property, three-dimensional network formability, superior mechanical properties, easy processability, and widespread availability, cellulosic materials have various functional groups acting as ideal sites for the immobilization of the indicator dye, which play a crucial role in the efficiency of CFFIs. Furthermore, anionic cellulose-derived polymers can act as an electrostatic binding site for positively charged freshness biomarkers, such as total volatile basic nitrogen compounds. This review covers the most-significant peer-reviewed papers on cellulosic material-based CFFIs for meat, fruits, and milk to understand the current research trends and recently developed cellulosic material-based CFFIs. The challenges related to cellulosic material-based CFFIs are presented, including their efficiency and selectivity to other biomarkers and the safety concerns related to certain ingredients, including indicator dyes, crosslinkers, and plasticizers, employed in their fabrication. Solution casting is the most widely used laboratory method for the preparation of cellulosic material-based CFFIs. However, solution casting is not viable for mass production owing to its long drying time. The thickness, dimension, and location of CFFIs inside the food package (their distance from the analytes) affect their colorimetric response. Thus, industrially viable methodologies, such as contact-type CFFIs using innocuous materials such as cellulose and its derivatives doped with food-grade indicator dyes, must be developed. This review shows that cellulosic material-based CFFIs doped with bio-based natural indicator dyes such as anthocyanins (ACNs) offer viable options for intelligent food packaging. Different approaches for improving the sensitivity and reactivity of ACNs are also addressed. Owing to their viability and potential, cellulosic material-based CFFIs will continue to remain an important research topic in the future. [ABSTRACT FROM AUTHOR]

Chocolate malt is widely used in craft beer production to provide aroma and color. Headspace solid-phase microextraction coupled with gas chromatography mass spectrometry technology (HS-SPME–GC–MS) was employed for the determination of volatiles in ten kinds of chocolate malt. 45 volatile compounds were perceived, including 12 nitrogen-containing heterocyclic compounds, 10 aldehydes, 6 furans, 5 phenols, 5 acids, 5 phenols, 3 alcohols, and 2 ketones. In addition, volatiles of pilsner malt, caramel malt, crystal malt, and coffee malt were investigated for comparison. Results revealed that there were 31 volatile compounds existed in all 14 samples. According to the principal component analysis (PCA), 26 volatiles were associated with the aroma of chocolate malt. Partial least square-discriminant analysis (PLS-DA) was also performed and found that 14 volatiles with variable importance in the projection (VIP) > 1 could be used as key volatile compounds to distinguish chocolate malt. Finally, the aroma attributes for chocolate malt were described as smoky and burnt through sensory evaluation. [ABSTRACT FROM AUTHOR]

Atmospheric nitrogen (N) deposition is altering grassland productivity and community structure worldwide. Deposited N comes in different forms, which can have different consequences for productivity due to differences in their fertilization and acidification effects. We hypothesize that these effects may be mediated by changes in plant functional traits. We investigated the responses of aboveground primary productivity and community functional composition to addition of three nitrogen compounds (NH4NO3, [NH4]2SO4, and CO[NH2]2) at the rates of 0, 5, 10, 20 g N m−2 yr−1. We used structural equation modeling (SEM) to evaluate how functional structure influences the responses of productivity to the three N compounds. Nitrogen addition increased community-level leaf chlorophyll content but decreased leaf dry matter content and phosphorus concentration. These changes were mainly due to intra-specific variation. Functional dispersion of traits was reduced by N addition through changes in species composition. SEM revealed that fertilization effects were more important than soil acidification for the responses of productivity to CO(NH2)2 addition, which enhanced productivity by decreasing functional trait dispersion. In contrast, the effects of (NH4)2SO4 and NH4NO3 were primarily due to soil acidification, influencing productivity via community-weighted means of functional traits. Our results suggest that N forms with different fertilizing and acidifying effects influence productivity via different functional traits pathways. Our study also emphasizes the need for in situ experiments with the relevant N compounds to accurately understand and predict the ecological effects of atmospheric N deposition on ecosystems. [ABSTRACT FROM AUTHOR]

In this study, macro-ringed benzo-aza-oxa-crown ethers were synthesized by a cyclization reaction between 2,2′-dithiodianiline and mono/di/tri/tetraethylene glycol dichloride/dibromide with Cs2CO3 as a catalyst under nitrogen atmosphere by the SN2 mechanism using the microwave synthesis method, which is one of the green chemistry methods. Structural characterizations of the original 2,2′-dithiodibenzo crown ether derivatives were confirmed with melting point, FT-IR, 1H NMR, 13C NMR, LC-MS/MS, elemental analysis, UV and fluorescence spectroscopy methods. In addition, the inhibition effects of these synthesized four crown ethers on human erythrocyte carbonic anhydrase (hCA I–II) isoenzyme activities were investigated. The synthesized compounds include aromatic benzene rings, nitrogen, sulfur, and oxygen donor atoms. The effects of aromaticity, S,S′-disulfide bond, nitrogen and oxygen donor atoms on the activity of carbonic anhydrase isoenzyme have been studied. (1,8,11,18)-Tetraaza[2,3-6,7-12,13-16,17]tetrabenzo-(4,5,14,15)-tetrathiocycloeicosane showed the highest inhibition effect on hCA I (Ki = 0.353±0.154 µM) and hCA II (Ki = 1.588±0.998 µM) enzyme. [ABSTRACT FROM AUTHOR]

Phenotypic plasticity and local adaptation can adjust individual responses to environmental changes across species' ranges. Studies addressing the implications of such traits have been underrepresented in the marine environment. Sargassum cymosum represents an ideal model to test phenotypic plasticity, as populations along the southwestern Atlantic Ocean display a sharp decrease in abundance toward distributional range limits. We (1) characterized the macroecological environment of S. cymosum across a latitudinal gradient, (2) evaluated potential differences in ecophysiological adjustments (biomass, photosynthetic pigments, phenolic compounds, total soluble sugars and proteins, and carbon–nitrogen—CN—content), and (3) tested for differences in thermal tolerance based on time series analyses produced from the present to contrasting representative concentration pathways scenarios (RCP) of future climate changes. Our results showed distinct macroecological environments, corresponding to tropical and warm temperate conditions, driving biomass and ecophysiological adjustments of S. cymosum. Populations from the two environments displayed contrasting thermal tolerances, with tropical individuals better coping with thermal stress when compared to more temperate ones (lethal temperatures of 33 °C vs. 30 °C); yet both populations lose biomass in response to increasing thermal stress while increasing secondary metabolites (for example, carotenoids and phenolic compounds) and decrease chlorophyll's content, Fv/Fm, total soluble sugars concentration and CN ratio, owing to oxidative stress. Despite evidence for phenotypic plasticity, significant future losses might occur in both tropical and warm temperate populations, particularly under the no mitigation RCP scenario, also known as the business as usual (that is, 8.5). In this context, broad compliance with the Paris Agreement might counteract projected impacts of climate change, safeguarding Sargassum forests in the years to come. [ABSTRACT FROM AUTHOR]

Two diazotrophic cyanobacteria (Anabaena cylindrica PCC 7122 and Nostoc sp. PCC 7120) were cultivated to produce cyanophycin, a nitrogen reserve compound, under nitrogen fixing conditions. In preliminary continuous experiments, Nostoc sp. was shown to be more efficient, accumulating a higher amount of cyanophycin and showing a greater capability to fix atmospheric nitrogen in the biomass (67 mgN d−1 of fixed nitrogen per liter of culture). The operating conditions were then optimized to maximize the cyanophycin productivity: the effect of incident light intensity, residence time and nitrogen availability were investigated. Nitrogen availability and/or pH played a major role with respect to biomass production, whereas phosphorus limitation was the main variable to maximize cyanophycin accumulation. In this way, it was possible to achieve a stable and continuous production of cyanophycin (CGP) under diazotrophic conditions, obtaining a maximum cyanophycin productivity of 15 mgCGP L−1 d−1. Key points: • Diazotrophic cyanobacteria produce stable amount of cyanophycin in continuous PBR. • Nostoc sp. proved to be more efficient in producing cyanophycin than Anabaena sp. • P deprivation is the major variable to increase cyanophycin productivity in continuous. [ABSTRACT FROM AUTHOR]

To monitor recovery from acidification, water chemistry was sampled in 11 Dutch moorland pools from 1978 to 2018. Changes were assessed by visual inspection of time series and tested non-parametrically. As a net result of all inputs and outputs, the median sulphate and ammonium concentrations in the surface water dropped by about 90%. This was accompanied by increases in pH, acid neutralizing capacity, and dissolved organic matter, and decreased metals, particularly toxic aluminium. Decreases of ammonium and sulphate in the surface water are considerably higher than in deposition, indicating the importance of losses to sediments and the atmosphere. The changes were greatest in pools with relatively flat banks exposed to the air in extremely dry summers. After the extremely dry summer of 1976, the changes were dramatic due to acidification by oxidation of the reduced sulphur and nitrogen compounds stored in the moorland pool bottom. In later dry years, the changes in the pools with flat banks were less extreme, as the sulphur stock in the sediment was depleted by winterly discharge to groundwater. In pools with steep banks, the sulphur compounds are retained in the sediment and may cause eutrophication by the displacement of phosphorus from iron compounds. [ABSTRACT FROM AUTHOR]

Background and aims: Nitrogen (N) addition affects plant biodiversity and community structure, subsequently altering the stability of above-ground net primary productivity (ANPP) in grassland ecosystems. However, the effect of adding different nitrogen compounds and their subsequent interactions with mowing on the stability of both below-ground net primary productivity (BNPP) and total net primary productivity (TNPP) are largely unknown.This study compared the impact of adding two nitrogen compounds, NH4NO3 and urea, on the temporal stability of ANPP, BNPP, and TNPP in mowed and unmowed saline-alkaline grasslands.We found that the ANPP temporal stability in unmowed grasslands was not affected by NH4NO3 addition but increased with urea addition. Conversely, the ANPP temporal stability in mowed grasslands decreased with NH4NO3 addition and was not affected by urea addition. Mowing decoupled the ANPP and BNPP temporal stability responses to nitrogen addition. Without mowing, the BNPP temporal stability in response to adding different forms of nitrogen aligned with that of ANPP; however, with mowing, the BNPP temporal stability was not affected by adding NH4NO3 or urea, exhibiting an inconsistent trend of change in comparison to the ANPP temporal stability. The ANPP resistance indirectly regulates the response of the BNPP temporal stability to nitrogen addition in unmowed grasslands, whereas the BNPP temporal stability was not affected by plant above-ground indicators in mowed grasslands.Overall, our study addresses the scarcity of research on ecosystem temporal stability in saline-alkaline grasslands and demonstrates that mowing management can regulate the effects of different forms of nitrogen addition on ecosystem stability.Methods: Nitrogen (N) addition affects plant biodiversity and community structure, subsequently altering the stability of above-ground net primary productivity (ANPP) in grassland ecosystems. However, the effect of adding different nitrogen compounds and their subsequent interactions with mowing on the stability of both below-ground net primary productivity (BNPP) and total net primary productivity (TNPP) are largely unknown.This study compared the impact of adding two nitrogen compounds, NH4NO3 and urea, on the temporal stability of ANPP, BNPP, and TNPP in mowed and unmowed saline-alkaline grasslands.We found that the ANPP temporal stability in unmowed grasslands was not affected by NH4NO3 addition but increased with urea addition. Conversely, the ANPP temporal stability in mowed grasslands decreased with NH4NO3 addition and was not affected by urea addition. Mowing decoupled the ANPP and BNPP temporal stability responses to nitrogen addition. Without mowing, the BNPP temporal stability in response to adding different forms of nitrogen aligned with that of ANPP; however, with mowing, the BNPP temporal stability was not affected by adding NH4NO3 or urea, exhibiting an inconsistent trend of change in comparison to the ANPP temporal stability. The ANPP resistance indirectly regulates the response of the BNPP temporal stability to nitrogen addition in unmowed grasslands, whereas the BNPP temporal stability was not affected by plant above-ground indicators in mowed grasslands.Overall, our study addresses the scarcity of research on ecosystem temporal stability in saline-alkaline grasslands and demonstrates that mowing management can regulate the effects of different forms of nitrogen addition on ecosystem stability.Results: Nitrogen (N) addition affects plant biodiversity and community structure, subsequently altering the stability of above-ground net primary productivity (ANPP) in grassland ecosystems. However, the effect of adding different nitrogen compounds and their subsequent interactions with mowing on the stability of both below-ground net primary productivity (BNPP) and total net primary productivity (TNPP) are largely unknown.This study compared the impact of adding two nitrogen compounds, NH4NO3 and urea, on the temporal stability of ANPP, BNPP, and TNPP in mowed and unmowed saline-alkaline grasslands.We found that the ANPP temporal stability in unmowed grasslands was not affected by NH4NO3 addition but increased with urea addition. Conversely, the ANPP temporal stability in mowed grasslands decreased with NH4NO3 addition and was not affected by urea addition. Mowing decoupled the ANPP and BNPP temporal stability responses to nitrogen addition. Without mowing, the BNPP temporal stability in response to adding different forms of nitrogen aligned with that of ANPP; however, with mowing, the BNPP temporal stability was not affected by adding NH4NO3 or urea, exhibiting an inconsistent trend of change in comparison to the ANPP temporal stability. The ANPP resistance indirectly regulates the response of the BNPP temporal stability to nitrogen addition in unmowed grasslands, whereas the BNPP temporal stability was not affected by plant above-ground indicators in mowed grasslands.Overall, our study addresses the scarcity of research on ecosystem temporal stability in saline-alkaline grasslands and demonstrates that mowing management can regulate the effects of different forms of nitrogen addition on ecosystem stability.Conclusions: Nitrogen (N) addition affects plant biodiversity and community structure, subsequently altering the stability of above-ground net primary productivity (ANPP) in grassland ecosystems. However, the effect of adding different nitrogen compounds and their subsequent interactions with mowing on the stability of both below-ground net primary productivity (BNPP) and total net primary productivity (TNPP) are largely unknown.This study compared the impact of adding two nitrogen compounds, NH4NO3 and urea, on the temporal stability of ANPP, BNPP, and TNPP in mowed and unmowed saline-alkaline grasslands.We found that the ANPP temporal stability in unmowed grasslands was not affected by NH4NO3 addition but increased with urea addition. Conversely, the ANPP temporal stability in mowed grasslands decreased with NH4NO3 addition and was not affected by urea addition. Mowing decoupled the ANPP and BNPP temporal stability responses to nitrogen addition. Without mowing, the BNPP temporal stability in response to adding different forms of nitrogen aligned with that of ANPP; however, with mowing, the BNPP temporal stability was not affected by adding NH4NO3 or urea, exhibiting an inconsistent trend of change in comparison to the ANPP temporal stability. The ANPP resistance indirectly regulates the response of the BNPP temporal stability to nitrogen addition in unmowed grasslands, whereas the BNPP temporal stability was not affected by plant above-ground indicators in mowed grasslands.Overall, our study addresses the scarcity of research on ecosystem temporal stability in saline-alkaline grasslands and demonstrates that mowing management can regulate the effects of different forms of nitrogen addition on ecosystem stability. [ABSTRACT FROM AUTHOR]

Ionic liquids based on 1-butyl-3-methylimidazolium (bmim) cations are capable of completely dissolving lignocellulosic biomass at elevated temperatures and are considered promising "green" solvents for creating new technologies for processing renewable plant feedstock (biorefining). Lignins obtained in such processes are characterized by the presence of significant amounts of nitrogen, while the nature of nitrogen-containing compounds in their chemical composition has not been fully elucidated yet. In the present work, MALDI mass spectrometry, capable of selectively recording signals of nitrogen-containing compounds, is proposed to study ionic liquid lignins (ILL). Model preparations of ILs obtained by treating spruce dioxane lignin with a [bmim]OAc ionic liquid at temperatures of 80–150°C are chosen as test samples. The recorded MALDI mass spectra show signals from hundreds of nitrogen-containing lignin oligomers with molecular weights up to 1500 Da. A feature of tandem mass spectra obtained using the CID technique is the presence of bmim signals, which indicates the covalent binding of the ionic liquid cation with lignin oligomers. An assumption has been made about the mechanism of such binding, which proceeds mainly with the participation of carbonyl groups in the lignin structure. [ABSTRACT FROM AUTHOR]

Synthetic hydrogels have been replaced by natural hydrogels due to their properties such as being long-lasting, more capacity for water absorption, high strength, and resistance. Recently, hydrogels have been defined as two- or multi-component systems consisting of three-dimensional networks of polymer chains that fill the space between macromolecules. Their water absorption efficiency depends on both polymeric nature and the capacity of the polymer network connections. Because of climate change and frequent droughts, fresh water supply has become a limiting factor for sustainable aquaculture development in Iran. Therefore, wastewater treatment and reuse can be a reasonable solution to meet the required water for expanding the aquaculture industry. The present study assessed the efficiency of a new hydrogel prepared from sugarcane waste (bagasse) to remove nitrogen and phosphate compounds from the effluent of fish farms. First, the hydrogel was prepared during the polymerization process, and then, in order to determine the optimal absorption, it was tested in a discontinuous system by performing absorption isotherm calculations. In cellulose/chitosan nanocrystalline hydrogel nanosorbent, the removal rates for nitrate, nitrite, and phosphate were 84.3%, 86%, and 90.9%, respectively. Optimal adsorption was determined at acidity of 6, time of 30 min, temperature of 40 ℃, concentration of 100 mg/L, and adsorbent dose of 0.5 g. A comparison of adsorption isotherm models showed more conformity with Freundlich and Tamkin absorption models with correlation coefficients of 0.99 and 0.97 for nitrate, 0.98 and 0.91 for nitrite, and 0.99 and 0.93 for phosphate, respectively. [ABSTRACT FROM AUTHOR]

Background: The high amount of soluble carbohydrates and the reduced dry matter content in cactus pear can cause excessive fermentation, resulting in nutrient losses, when it is preserved in the silage form. Thus, the association of cactus pear with elephant grass in the production of mixed silages may reduce nutritional losses during the ensiling process. Thus, the aim was to evaluate the mineral profile, carbohydrates fractionation, nitrogen compounds, and in vitro gas production of elephant grass silages associated with a cactus pear levels (0, 150, 300, and 450 g/kg on dry matter basis). The study was carried out in a completely randomized design, with 4 treatments and 5 replications, totaling 20 experimental silos. Results: The increase in cactus pear levels in elephant grass silages composition provided an increase in the contents of K (P = 0.013), Ca (P < 0.001), Mg (P < 0.001), Na (P = 0.001), B (P = 0.044) and Zn (P = 0.016), reduced P (P = 0.039) and promoted a quadratic effect for Fe (P = 0.045) content. The addition of cactus pear levels in elephant grass silages increased the total carbohydrates (P < 0.001) and A + B1 fraction (P = 0.002) and promoted a quadratic effect for B2 fraction (P = 0.032). For nitrogen compounds, the increase in cactus pear levels in elephant grass silages composition reduced the B1 + B2 fraction (P = 0.002) and increased the C fraction (P = 0.007). There was no effect of cactus pear levels on the in vitro gas production of elephant grass silages (P > 0.05). Conclusions: Under the experimental conditions, the addition of cactus pear in elephant grass silage at levels up to 450 g/kg dry matter does not affect the in vitro gas production, however, it improves the mineral profile, contributes to the increase in the total carbohydrate content and the A + B1 fraction in the silages. Besides this, cactus pear addition reduces the B1 + B2 protein fraction, increasing the fraction C content in the silages, suggesting the necessity to supply an additional soluble nitrogen source for good ruminal functioning. [ABSTRACT FROM AUTHOR]

The main focus of synthetic chemistry is to develop safe and therapeutically active compounds by employing green synthetic reaction conditions. The azole nuclei have been the center of attention for decades owing to their diverse pharmacological activities. Various synthetic routes have been identified for the synthesis of pharmacologically active derivatives of azoles. Coupling reactions have gained much importance in synthetic chemistry the most basic type of joining two chemical species. The coupling reactions of azoles include alkylation and arylation of the nitrogen atom which yields many compounds possessing significant therapeutical potential, only having limitations related to expensive catalyst systems, bulky ligands, time constraints etc. These limitations can be overcome by employing safe and economical catalyst systems involving nanoparticles. These nanosystems are easy to formulate and offer the advantage of catalyzing the reaction more rapidly with significantly improved yield. In this review, two of the most important azole nuclei—triazole and benzimidazole—are discussed on the basis of their diverse pharmacological properties making them effective drug candidates for further development to overcome emerging diseases. In particular, 1,2,4-triazole and 2-methlybenzimidazole have wide range of therapeutic activities such as anti-inflammatory, antioxidant, antimicrobial, antidiabetic, anthelmintic, analgesic, antihypertensive, anticonvulsant, anticancer, antiulcer, antiprotozoal, antimycobacterial, anti-HIV and antipsychotic. [ABSTRACT FROM AUTHOR]

The hydro-fluctuation belt is a vital ecosystem with rich resources and environmental regulation ability. It plays a critical role in maintaining biodiversity, the balance in aquatic-terrestrial ecosystem and water purification. However, the water environmental system in the hydro-fluctuation belt is complex and dynamic with a large number of uncertain factors, and these factors are interrelated, which can be defined as a grey system. This paper evaluated the effects of environmental influencing factors on nitrogen diffusion fluxes at sediment-water interface and determined the main controlling factor by application of grey correlation analysis. The monitoring of nitrogen diffusion fluxes at sediment-water interface in the hydro-fluctuation belt of Danjiangkou reservoir lasted for one year, the index system of environment influencing factors were determined, and the procedures of the grey correlation analysis method were introduced. Analysis results indicate that the main controlling factors for diffusion flux of ammonium, nitrate, nitrite and inorganic nitrogen were dissolved oxygen, temperature, pH and pH, respectively. The nitrogen compounds accumulated in the sediment for a long duration can be transformed into ammonium nitrogen by microorganisms, which increased the nitrogen release risk. Therefore, it is an effective way to regulate the pH in the overlying water to control nitrogen pollution. Since the process of nitrogen migration and transformation can be affected by many direct and indirect influential factors, it is quite difficult to achieve satisfactory nitrogen removal effects by regulating single influential factor. However, it provided a possible new way for sediment nitrogen pollution evaluation and regulation. [ABSTRACT FROM AUTHOR]

The presence of carbon and nitrogenous compounds in mango processing by-products makes them excellent substrates for the biosynthesis of many microbial metabolites using the fermentation process. Pre-treatment of the substrate with retention of crucial microbial growth supporting compounds is vital for designing and optimizing fermentation media for enhanced production of desired metabolites. Keeping this in mind, we analyzed the effect of convective hot air drying (50, 60, 70, and 80 °C) conditions on the bioactive compounds (especially carbohydrates and nitrogen), physico-chemical attributes, mineral elements, fermentable sugar, and microbial safety of mango peels (Cv-chausa) powder. Results indicated that different drying temperatures insignificantly (P > 0.05) affected the carbohydrates and reducing sugar (except at 80 °C) along with nitrogen and protein contents. The pH, ascorbic acid, total phenolic, and antioxidant activity decreased with an increase in drying temperatures. Inductively coupled plasma-optical emission spectrometry analysis revealed increased concentrations of majority nutrients with incremental temperature, possibly due to excessive desiccation and substantial dry matter increase. After 30 days at room temperature storage, the microbial load was within safe limits, as samples were devoid of food pathogens. Briefly, the study suggests the effectiveness of convective hot air drying (at 70–80 °C) for efficient drying and prolonged storage of stable powdered form mango peels (MP). The obtained MP powder can be used as a feedstock (with safe storability, preserved bioactive, primarily carbon and nitrogen compounds) for the year-round use in the microbial fermentation process and potential development of functional food. [ABSTRACT FROM AUTHOR]