Nitrogen Research Articles

Fate and Transformation of 15 Classes of Per- and Polyfluoroalkyl Substances in Aqueous Film-Forming Foam (AFFF)-Amended Soil Microcosms.

The environmental fate of per- and polyfluoroalkyl substances (PFAS) in aqueous film-forming foams (AFFFs), especially those synthesized by electrochemical fluorination (ECF) processes, remains largely unknown. This study evaluated the transformation of AFFF-derived ECF-based precursors in aerobic soil microcosms amended with a historically used AFFF formulation (3M Light WaterTM). Fifteen classes of PFAS, including AFFF components and transformation products, were identified or tentatively identified by suspect screening/nontargeted analysis (SSA/NTA) throughout a 308-day incubation. This study demonstrates that AFFF-derived ECF-based precursors serve as sources of perfluoroalkane sulfonamides (FASAs) and perfluoroalkyl acids (PFAAs), which are commonly detected at AFFF-impacted sites. Temporal sampling provided evidence for biotransformation of multiple precursors including tri- or dimethyl ammonio propyl perfluoroalkane sulfonamides. Additionally, the environmental stability (i.e., resistance to transformation) of ECF-based precursors was found to depend upon structural characteristics, including perfluoroalkyl chain length, presence of sulfonamide or carboxamide groups, and functional groups (e.g., a branch of carboxyalkyl group) attached to the nitrogen atoms. These findings provide insights into the transformation pathways of AFFF-derived PFAS and other structurally similar ECF-based PFAS, which will support the management and remediation of PFAS contamination at legacy AFFF-impacted sites.

Interfacial Characteristics of Ice-Supporting Substrates via Molecular Dynamics Simulations.

Ice accumulation on aircraft surfaces poses significant safety and performance risks, necessitating the development of coatings to prevent ice adhesion. The present work focuses on characterizing the interfacial properties of ice on various substrates through molecular descriptors. We follow the hypothesis that has been previously proposed in several experimental works according to which a disordered, quasi-liquid layer (QLL) of water at the substrate/ice interface is developed, which in turn acts as a self-lubricant reducing material's ice adhesion strength. To put this idea into the test, we conducted extensive molecular dynamics (MD) simulations on ice supported by different types of substrates, such as graphite, boron nitride, and a cross-linked epoxy polymer. Our findings reveal that the ice structure becomes disordered near the interface for all substrates, with a more pronounced effect in the polymer substrate. The formation of QLL at the interface was quantified using metrics such as local density, Q6 order parameter, and hydrogen bonding. The polymer substrate showed a thicker QLL compared to the two flat surfaces, as this was verified by both the significant differences in the local water density profiles and the distribution of the employed order parameter. The latter ones were directly correlated to the development of hydrogen bonds between the interfacial water molecules and the polymer substrate's polar atoms, which was found to induce a more intense disruption of ice's crystal structure. Moreover, our analysis revealed that the polymer's oxygen atoms contribute more to hydrogen bonding with the water molecules than the nitrogen atoms, with hydroxyl oxygens (-OH) contributing more compared to the epoxy ones (-O-). The analysis related to the dynamics of the interfacial water molecules revealed a substantial reduction in mobility on the epoxy, exceeding the slowdown observed on boron nitride, with graphite demonstrating the least reduction in dynamic behavior among the substrates studied.

CHEMICAL TRANSFORMATIONS OF PYRROLO-1,5-BENZODIAZEPINE DERIVATIVES

One of the most important tasks in modern organic chemistry is search and development of simple synthesis methods and study of the chemical properties of new biologically active substances. Pyrrolo-1,5-benzodiazepine derivatives refer to an important class of nitrogen-containing heterocycles with a wide range of biological activities. Based on the structure of the synthesized 4,5-dihydropyrrolo[1,2,3-e,f][1,5]-benzodiazepin-6(7H)-ones, it can be concluded that they possess high reactivity towards chemical transformations. This work examines the chemical properties of these derivatives (hydrolysis, transesterification, restoration, alkylation, amidation) and evaluates the acid-base properties of pyrrolo-1,5-benzodiazepine derivatives. As a result of the research we obtained two values for ionization constants that correspond to the protonation of the amide group of the diazepine ring and the indole part of the molecule. Protonation of the amide group of the diazepine ring can occur either on the nitrogen atom or the oxygen atom. However, O-protonation is more likely. In this case the mesomeric bonding of the electron pair of nitrogen atom with π/r-electron sextet of the benzene ring is not disrupted. These data provide valuable information on the reliance of the biological activity of the compound on its chemical structure and its chemical properties. The prospects for studying the biological activity of synthesized pyrrolo-1,5-benzodiazepine derivatives for their further use in medical practice is demonstrated.

Innovative Urea Formation Using Microwave Plasma-Water Interaction: A Study on Reactive Species and Plant Growth

Abstract This study explores the production of urea using microwave (MW) plasma-water interaction with air, N₂, CO₂, and a N₂ + CO₂ gas mixture to generate plasma-activated water (PAW). After 180 seconds of plasma exposure, air plasma reduced the pH to 3.3 and increased the oxidizing potential by 127.1%, making the water acidic and oxidizing, while the N₂ + CO₂ plasma raised the pH to 10.1 and reduced the oxidizing potential by 33.8%, creating basic and reducing conditions. PAW from air plasma produced the highest NO₂⁻ (51 mg L⁻¹) and NO₃⁻ (295 mg L⁻¹) concentrations, while the N₂ + CO₂ mixture generated the most NH₄⁺ (2250 mg L⁻¹), and CO₂ plasma produced the most CO₃²⁻ ions. Notably, urea formation (plasma urea) was observed only with CO₂ and N₂ + CO₂ plasmas, attributed to the formation of stable compounds like NH₄⁺ and NH₂COO⁻. In this process, NH₄⁺ ions formed via the reaction between atomic nitrogen and water, and their subsequent reaction with NH₂COO⁻ ions in the aqueous phase led to urea synthesis. The N₂ + CO₂ plasma produced 2991% more urea than CO₂ plasma. Plasma urea enhanced seed germination and plant growth, increasing germination rates for carrots by 10.67% and coriander by 15.6%. Shoot lengths grew by 38.6% for carrots and 30.8% for coriander, while root lengths improved by 24.24% and 37.5%, respectively, compared to controls. This study highlights MW plasma-water interaction as a sustainable, energy-efficient alternative to conventional urea production, offering significant environmental benefits and improved agricultural performance.

Isolation and Characterization of a New High-Yield Hydrogen-Producing Strain, Clostridium sulfidigenes CS3, from Anaerobic Sludge in the To Lich River

Hydrogen is a vital gas, recognized for its role as a renewable, clean energy source and its importance as a feedstock in multiple industries, leading to a significant rise in hydrogen production demand in recent years. In this context, a high-yield hydrogen-producing mesophilic bacterium, strain CS3, was isolated from sludge and identified as Clostridium sulfidigenes CS3 through 16S rRNA gene analysis and physio-biochemical testing, revealing novel characteristics of this species. This study systematically investigated various factors influencing biological hydrogen production through fermentation, including medium components (like substrates and nitrogen sources) and environmental conditions (initial pH, incubation temperature, duration, and agitation). The research also explored methods to boost hydrogen yield. The maximum yield of 2.1 mol H₂/mol glucose was obtained under optimal conditions: a medium with 10 g/L glucose, an initial pH of 7.0, incubation at 37°C for 48 hours, and agitation at 200 rpm, with supplementation of organic nitrogen sources (10 g/L peptone and 10 g/L yeast extract). The performance of C. sulfidigenes CS3 was compared with other known hydrogen-producing strains, highlighting the superior hydrogen productivity of this species. This is also considered a new discovery in the hydrogen-producing ability of this species. The findings suggest that C. sulfidigenes CS3 could be a promising candidate for biohydrogen production, providing an environmentally friendly alternative to fossil fuels.

Response of Microbiological Properties to Short-term Nitrogen Addition in Perennial Alpine Cultivated Grassland

Removing nitrogen limitation is necessary to increase plant productivity in alpine grasslands. A short-term nitrogen addition experiment was conducted to understand the effects of nitrogen addition on the soil physicochemical properties and microbial community structure of perennial alpine cultivated grassland in the region around Qinghai Lake. From June to August 2022, four N application gradients （T0： 0 kg·hm-2·a-1, T1： 22.5 kg·hm-2·a-1, T2： 45 kg·hm-2·a-1, T3： 67.5 kg·hm-2·a-1） were set up in a four-age perennial cultivated grassland, and soil samples were collected from the 0-20 cm soil layer. The soil physical and chemical properties and microbial community structure were determined under the different treatments. The results showed that soil water content （SWC）, soil organic carbon （SOC）, ammonium nitrogen （NH4+-N）, nitrate nitrogen （NO3--N）, available nitrogen （AN）, available phosphorus （AP）, total phosphorus （TP）, total nitrogen （TN）, and total carbon （TC） tended to increase with the increase in nitrogen application level and the T3 treatment significantly decreased the soil pH. Nitrogen addition did not significantly alter the Alpha diversity of soil microbial communities and different levels of nitrogen application affected the structure of soil microbial communities to different degrees. The T1 and T2 treatments increased the number of soil bacteria and fungi and T3 treatment decreased the number of soil bacteria and fungi. Nitrogen addition increased the relative abundance of the dominant flora of Actinobacteriota, Zygomycota, Blastococcus, and Gibberella and decreased the relative abundance of the dominant flora of Proteobacteria, Bacteroidota, Sphingomonas, and Claroideoglomus. RDA analysis showed that SOC and soil electrical conductivity （EC） were the key soil physicochemical factors affecting changes in soil bacterial communities, and soil pH was the main factor affecting the distribution of soil fungal communities. Collectively, 67.5 kg·hm-2·a-1 may be the optimal level of N application to improve the soil environment of perennial alpine cultivated grasslands.

Crystal Structures of Sulfobetaine-8 Solvates: Bend Hydrophobic Chains and Doubly Charge-Assisted Hydrogen Bonds N+CH⋯−O3S

Three novel solvatomorphs (C13H29NO3S•CH3OH, 1; C13H29NO3S•0.113(H2O), 2; C13H29NO3S•0.038(H2O), 3) of zwitterionic sulfobetaine-8 were obtained and their structures were determined using single-crystal X-Ray diffraction. In all cases dimethyl–amino substituted hydrophobic chains -(CH2)3-N+Me2-(CH2)7-Me exhibit kinks at nitrogen atoms resulted from strong intra- and intermolecular CH⋯O hydrogen bonds between negatively charged sulfonic anion -O3S- and positively charged tetraalkylammonium fragments. Periodic (solid state) DFT calculations for structure 1 showed that the energy of the intermolecular hydrogen bonds CH…O is very high, at about 17 kJ/mol. In hydrates 2 and 3, water molecules play the structure-forming role since they interconnect hydrophobic layers by HOH…-O3S hydrogen bonds. The location of only partially occupied water molecules in the interlayer space leads to low stability of both crystals 2 and 3 in open air.

Hexagonal Boron Nitride as a Two-Dimensional Surfactant: Low-Density Flame-Resistant Composites Based on Boron Nitride Exfoliated by an Interface Trapping Technique.

Hexagonal boron nitride (hBN) is a two-dimensional material isoelectric to graphene. It has a hexagonal structure with alternating boron and nitrogen atoms and is electrically insulating, thermally conductive, and chemically inert. However, like graphene, its use as a functional nanofiller requires exfoliation. Here, we present a method for exfoliating and dispersing hexagonal boron nitride (hBN) sheets within a polymer matrix. This is achieved by a solvent interface trapping method (SITM), where hBN exfoliates and spreads at a high-energy oil/water interface, separating the two phases and lowering the system's free energy. hBN thus acts as a surfactant, allowing us to form stable water-in-oil emulsions stabilized by films of overlapping hBN sheets. Polymerizing the continuous oil phase results in polymerized high internal phase emulsions (polyHIPE), with the foam cells lined with hBN. In the investigation presented here, we use acoustic spectroscopy, optical and electron microscopy, and image analysis to study the emulsion and polyHIPE formation mechanisms. We find that the amount of hBN used, the flake size of the hBN, the mixing time, the type of initiator used, and the oil-to-water ratio all play a role in the morphology of the final polyHIPE. Lastly, we demonstrate the flame-retardant properties of the hBN polyHIPEs and show that, at 1% loadings, the presence of hBN prevents dripping and relighting of the composites, even when the material is heated to a red glow.

DFT Study of Coordination of N-Monochlorosubstituation Derivatives of Biguanide

Biguanides [HN=C(NR1R2)-NH-C(NR3R4)=NH] constitute an important family of molecules used as drugs in the treatment of diabetes. It is known that some transition metal complexes with given organic compounds deeply increase both therapeutic actions of the metal and the organic compound. The chlorine atom, a preferred substitute in pharmacy, improves the effectiveness of drugs and reduces their side effects. The mesmeric +M effect of the chlorine atom would make it possible to enhance the nucleophilic character of any N-chlorosubstituted nitrogen. In this work a theoretical study of coordination of N-chlorine derivatives of biguanide is carried out mainly at the DFT/B3LYP/6-31G (d, p) level. The Gaussian 09 & 03, HyperChem softwares and the DCENT-QSAR program are used. The coordinating possibility of each ligand were studied analyzing some coordinating indicators as: interatomic bond lengths, atomic charges, molecular electrostatic potentials, frontier orbital structures and electrophilic superdelocalizability. Then, the formation of its complex with zinc (II) has been calculated. The results of the calculations revealed the imine nitrogen atoms as the most favorable coordination sites. Bioactive complexes of these ligands with Zn (II) are modelled. Testing the bioavailability of obtained complexes according to the Lipinski rules of 5, we noticed that they can be considered as drug-candidates.

Impact of Organic Fertilizer Substitution and Chemical Nitrogen Fertilizer Reduction on Soil Enzyme Activity and Microbial Communities in an Apple Orchard

Impact of Organic Fertilizer Substitution and Chemical Nitrogen Fertilizer Reduction on Soil Enzyme Activity and Microbial Communities in an Apple Orchard

8-(Pyridin-2-yl)quinolin-7-ol and Beyond: Theoretical Design of Tautomeric Molecular Switches with Pyridine as a Proton Crane Unit

Long-range proton transfer in several conjugated proton cranes, originating from 7-hydroxy quinoline as a proton transfer platform, has been investigated theoretically by means of DFT and TD-DFT methodology. Major emphasis was given to their applicability to provide clean switching upon irradiation. The border conditions require the existence of a single enol tautomer in the ground state, which under excitation through a series of consecutive exited and ground state intramolecular proton transfer steps is transferred to the keto tautomer. It was shown that the most suitable candidates are based on using iso-quinoline, pyrimidine and 4-nitropyridine as proton crane units. Their suitability is a function of aromaticity changes, the basicity of the nitrogen atom from the proton crane unit and the structural effects originating from their conjugation with 7-hydroxy quinoline.

Current Advances in Synthesis and Therapeutic Applications of Thiazole and its Derivatives

Thiazole, a five-membered heterocyclic compound with sulfur and nitrogen atoms, serves as a fundamental scaffold in medicinal chemistry. The aromatic nature and diverse substitution patterns of the thiazole ring system enable its extensive applications in drug development. Multiple synthetic routes, from classical Hantzsch synthesis to modern methods, yield varied thiazole derivatives under specific reaction conditions. The biological importance of thiazole-containing compounds extends to anticancer, antimicrobial, and antidepressant activities. Several thiazole-based drugs have demonstrated significant therapeutic effects - dasatinib and dabrafenib as antitumor agents target specific kinases to inhibit cancer cell growth, while ampicillin and myxothiazole exhibit broad-spectrum antimicrobial properties. Structure-activity relationship studies have revealed that substituents at different positions of the thiazole ring significantly influence the biological activity. For instance, attachment of thiourea linker at position 2 enhances anticancer properties, while aryl/alkyl substitutions affect chemical stability and pharmacokinetic properties. The mechanistic understanding of thiazole-based compounds has led to targeted drug development. Recent synthetic methods have produced novel thiazole derivatives with enhanced therapeutic properties, particularly in antimalarial activity where thiazolyl benzenesulfonamide carboxylates show promising results against Plasmodium falciparum

Cooperative Catalysis in Stereoselective O- and N-Glycosylations with Glycosyl Trichloroacetimidates Mediated by Singly Protonated Phenanthrolinium Salt and Trichloroacetamide.

The development of small-molecule catalysts that can effectively activate both reacting partners simultaneously represents a pivotal pursuit in advancing the field of stereoselective glycosylation reactions. We report herein the development of the singly protonated form of readily available phenanthroline as an effective cooperative catalyst that facilitates the coupling of a wide variety of aliphatic alcohols, phenols, and aromatic amines with α-glycosyl trichloroacetimidate donors. The glycosylation reaction likely proceeds via an SN2-like mechanism, generating β-selective glycoside products. The developed protocol provides access to O- and N-glycosides in good yields with excellent levels of β-selectivity and enables late-stage functionalization of O- and N-glycosides via cross-coupling reactions. Importantly, this method exhibits excellent β-selectivity that is unattainable through a C2-O-acyl neighboring group participation strategy, especially in the case of glycosyl donors already containing a C2 heteroatom or sugar unit. Kinetic studies demonstrate that the byproduct trichloroacetamide group plays a previously undiscovered pivotal role in influencing the reactivity and selectivity of the reaction. A proposed mechanism involving simultaneous activation of the glycosyl donor and acceptor by the singly protonated phenanthrolinium salt catalyst with the assistance of the trichloroacetamide group is supported by kinetic analysis and preliminary computational studies. This cooperative catalysis process involves four consecutive hydrogen bond interactions. The first interaction occurs between the carbonyl oxygen of the trichloroacetamide group and the hydroxyl group of alcohol nucleophile (C═O···HO). The second involves the trichloroacetamide-NH2 forming a hydrogen bond with the nitrogen atom of the phenanthroline (NH···N). The third involves the donor trichloroacetimidate (═NH) engaging in a hydrogen bond interaction with the phenanthrolinium-NH (NH···N═H). Lastly, the protonated trichloroacetimidate-NH2 forms a hydrogen bond with the fluorine atom of the tetrafluoroborate ion.

Biodegradation of various edible oils and fat by Staphylococcus petrasii sub sp. jettensis VSJK R1 for application in bioremediation of lipid rich restaurant wastewater.

The disposal of fat, oil, and grease (FOG) pollutants from various sources, including restaurants, food processing facilities, and domestic kitchens, poses significant challenges to wastewater treatment systems. In this study, we isolated and characterized a novel bacterial strain. The result of 16S rRNA gene and phylogenetic analysis showed that the isolate was Staphylococcus petrasii sub sp. jettensis and named as VSJK R1 (Fig. S1). It was tested for its biodegradation potential of FOG contaminants. Our investigation revealed that Staphylococcus petrasii sub sp. jettensis VSJK R1 effectively degraded a variety of edible oils, including soybean, sunflower, cottonseed, palm, groundnut, and butter, with notable efficiency. Optimization studies were conducted to determine the optimal conditions for biodegradation, including the effects of nitrogen, carbon, phosphorus, pH, temperature, and salt concentration. Results indicated that organic nitrogen sources and glucose as carbon source significantly enhanced biodegradation rates, while the addition of phosphorus further improved degradation efficiency within specific concentration ranges. Moreover, the optimal pH for biodegradation was found to be neutral, with temperature ranging between 22°C and 45°C favoring microbial activity. Remarkably, Staphylococcus petrasii sub sp. jettensis VSJK R1 exhibited resilience to high salt concentrations, making it suitable for treatment of wastewater with elevated salt content. Additionally, comparative studies with other microbial strains underscored the unique biodegradation capabilities of Staphylococcus petrasii sub sp. jettensis VSJK R1, particularly in degrading various edible oils. The results suggest promising applications of this novel isolate in bioremediation efforts targeting FOG pollutants in wastewater treatment plants and grease traps. Future research may focus on scaling up the bioremediation process and field testing the efficacy of Staphylococcus petrasii sub sp. jettensis VSJK R1 in real-world wastewater treatment scenarios.

Effect of mulching and organic manure on maize yield, water, and nitrogen use efficiency in the Loess Plateau of China.

Current agricultural practices prioritize intensive food production, often at the expense of environmental sustainability. This approach results in greenhouse gas emissions and groundwater pollution due to over-fertilization. In contrast, organic agriculture promotes a more efficient use of non-renewable energy, improves soil quality, and reduces ecological damage. However, the effects of mulching and organic manure on maize yield, water use efficiency (WUE), and nitrogen use efficiency (NUE) in China's Loess Plateau have not been sufficiently researched. In 2017 and 2018, an experiment utilizing a randomized complete block design with two factors (two mulching levels × three organic nitrogen application rates) was conducted. The water content of the upper soil layer was found to be 12.6% to 19.4% higher than that of the subsoil layer. Across all soil depths and years, the soil nitrate-N content in mulched treatments was 10% to 31.8% greater than in non-mulched treatments with varying organic nitrogen rates. Additionally, mulching resulted in an increase in grain yield of 9.4% in 2017 and 8.9% in 2018 compared to non-mulched treatments. A significant interaction was observed between mulching and organic nitrogen application rate concerning WUE, alongside a negative correlation between WUE and NUE. These findings suggest that the application of 270 kg N ha-1 of sheep manure in conjunction with mulching is a highly recommended practice for the Loess Plateau, thereby supporting sustainable agricultural strategies.

A text-based, generative deep learning model for soil reflectance spectrum simulation in the solar range (400–2499 nm)

Soil spectral reflectance is a necessary input for land surface and radiative transfer models, and can be used to infer soil properties. Numerous soil reflectance inversion models have been developed based on mechanistic approaches, each with their own limitations. Mechanistic models based on radiative transfer theory are usually based on only a few input soil properties, whereas data-driven approaches are limited by high non-uniformity of available published datasets that severely limits the amount of data usable for model calibration. To address these limitations, a fully data-driven soil optics generative model (SOGM) for simulation of soil reflectance spectra from soil property inputs was developed based on the denoising diffusion probabilistic model (DDPM). The model was trained on an extensive dataset comprising nearly 180,000 soil spectra-property set pairs from 17 published datasets. The model generates soil reflectance spectra from text-based inputs describing soil properties and their values rather than only numerical values and labels in binary vector format, which means the model can handle variable formats for property reporting. Because the model is generative, it can simulate reasonable output spectra based on an incomplete set of available input properties, which becomes more reliable as the input property set becomes more complete. Two additional sub-models were also built to complement the SOGM: a spectral padding model that can fill in the gaps for spectra shorter than the target solar range (400 to 2499 nm), and a wet soil spectra model that can estimate the effects of water content on soil reflectance spectra given the dry spectrum predicted by the SOGM. It can also be easily integrated with other soil–plant radiation models used for remote sensing research such as PROSAIL and Helios 3D plant modeling software. The testing results of the SOGM on new datasets not included in model training demonstrated that the model can generate reasonable soil reflectance spectra based on available property inputs. Results also show soil clay/sand/silt fraction, organic carbon content, nitrogen content, and iron content tended to be important properties for spectra simulation. Inclusion of some trace minerals like nickel as model inputs decreased model performance because of their low concentrations and large propensity for ground-truth measurement error.

Ionic Crosslinking of Linear Polyethyleneimine Hydrogels with Tripolyphosphate

In this work, the mechanical properties of hydrogels based on linear polyethyleneimine (PEI) chemically crosslinked with ethyleneglycoldiglycidyl ether (EGDE) were improved by the ionic crosslinking with sodium tripolyphosphate (TPP). To this end, the quaternization of the nitrogen atoms present in the PEI structure was conducted to render a network with a permanent positive charge to interact with the negative charges of TPP. The co-crosslinking process was studied by 1H high-resolution magic angle spinning (1H HRMAS) NMR and X-ray photoelectron spectroscopy (XPS) in combination with organic elemental analysis and inductively coupled plasma mass spectrometry (ICP-MS). In addition, the mobility and confinement of water molecules within the co-crosslinked hydrogels were studied by low-field 1H NMR. The addition of small amounts of TPP, 0.03 to 0.26 mmoles of TPP per gram of material, to the PEI-EGDE hydrogel resulted in an increase in the deformation resistance from 320 to 1080%, respectively. Moreover, the adsorption capacity of the hydrogels towards various emerging contaminants remained high after the TPP crosslinking, with maximum loading capacities (qmax) of 77, 512, and 55 mg g−1 at pH = 4 for penicillin V (antibiotic), methyl orange (azo-dye) and copper(II) ions (metal ion), respectively. A significant decrease in the adsorption capacity was observed at pH = 7 or 10, with qmax of 356 or 64 and 23 or 0.8 mg g−1 for methyl orange and penicillin V, respectively.

Atomic adsorption mechanism and initial growth of 2D GaN on graphene, h-BN and MoS2: A first principles study

Van der Waals epitaxial growth strategy on two-dimensional substrates presents a promising way for synthesizing hexagonal gallium nitride (h-GaN). This study investigates the most stable adsorption configurations of gallium (Ga) and nitrogen (N) atoms on graphene, h-BN, and MoS2 surfaces and further study the initial formation of GaN islands using the first-principles method. The interaction modes between Ga and N atoms with the substrates are analyzed using the Electron Localization Function (ELF), revealing the microscopic adsorption mechanism. Furthermore, diffusion behaviors of Ga and N atoms on the three substrates are evaluated via Climbing Image Nudged Elastic Band (CI-NEB) calculations, which shows that Ga diffuses via a sliding mechanism, while N diffusion involves bond-breaking and re-bonding events. N atom diffusion in the z-direction on these substrates are identified for the first time and the corresponding energy barriers are determined. Additionally, the growth morphology of 2D GaN on MoS2 is predicted by analyzing the competition between adatom-substrate and adatom-adatom interactions, and the possible morphology of initial 2D GaN islands is investigated. Our findings reveal that MoS2 is a favorable substrate for the growth of 2D h-GaN, providing theoretical insights to guide future experimental efforts.

Recent Progress in Isolating and Purifying Amide Alkaloids from their Natural Habitats: A Review

: Alkaloids are nitrogen-containing chemical compounds found in nature. Many alkaloids are heterocyclic in nature. They are nitrogen-based organic compounds with the nitrogen atoms enclosed in a heterocyclic ring. The chemical "pro alkaloid" is derived from the alkyl amines in it. Many ancient people, long before the advent of organic chemistry, recognized that many of these substances have measurable effects on the body's physiological functions. Alkaloids are a type of natural substances that are classified as secondary metabolites. Many different types of organisms create alkaloids, which are a class of natural products. Alkaloids showed antifungal, local anesthetic, anti-inflammatory, anticancer, analgesic, neuropharmacologic, antimicrobial, and many other activities. Amines, as opposed to alkaloids, are the more common classification for naturally occurring compounds that contain nitrogen in the exocyclic position (such as mescaline, serotonin, and dopamine). An amide molecule has a nitrogen atom that is chemically bound to a carbon atom in the carbonyl group. The -oic acid ending of the corresponding carboxylic acid is converted to -amide to form the correct nomenclature for an amide. This article offers an overview of numerous techniques for extracting, separating, and purifying alkaloids for use in natural medicine.

Involvement of CN Sites in Solvothermally Engineered Metal-Free Carbon Material From Weed Lantana camara for the Detection of Mercury Ions: Experimental and DFT Insights.

Embarking on a journey to decipher the role of active sites in the detection and removal of toxic mercury(II) ions from polluted water, the surface of thermally engineered biomass derived carbon matrix NC-180 was customized with nitrogen atoms. The HR-TEM and XRD analyses revealed the amorphous nature of Lantana camara derived carbon material with small spherical flakes embedded in it. XPS analysis indicated the presence of pyrrolic, pyridinic, and graphitic N atoms, which was further confirmed by FT-IR analysis. The material shows quenching effect in presence of Hg2+ ions resulting in the "turn off" effect with a detection limit of 7.2 nM. The activity of NC-180 was recovered through "turn on" effect in the presence of L-cysteine. Furthermore, the mystery of binding of mercury(II) ions with N-sites is clarified through its comparison with other materials bearing sulfur and oxygen functional groups designated as AC-180, SC-180, and NSC-180. The conclusive evidence for efficient binding of nitrogen sites in NC-180 with mercury(II) ions is derived from various analyses, including 1H-NMR, FT-IR, XPS, and density functional theory. Notably, sustainability is achieved through utilization of toxic weed L. camara for the preparation of this selective carbon material for detection and adsorption of mercury(II) ions.