Characterization of halogenated organic compounds by the Fourier transform ion cyclotron resonance mass spectrometry: A critical review.

Halogenated organic compounds (HOCs), widely present in various environments, are generally formed by natural processes (e.g., photochemical halogenation) and anthropogenic activities (e.g., water disinfection and anthropogenic discharge of HOCs), posing health and environmental risks. Therefore, in-depth knowledge of the molecular composition, transformation, and fate of HOCs is crucial to regulate and reduce their formation. Because of the extremely complex nature of HOCs and their precursors, the molecular composition of HOCs remains largely unknown. The Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) offers the most powerful resolution and mass accuracy for the simultaneous molecular-level characterization of HOCs and their precursors. However, there is still a paucity of reviews regarding the comprehensive characterization of HOCs by FT-ICR MS. Based on the FT-ICR MS, the formation mechanism, sample pretreatment, and analysis methods were summarized for two typical HOCs classes, namely halogenated disinfection byproducts and per- and polyfluoroalkyl substances in this review. Moreover, we have highlighted data analysis methods and some typical applications of HOCs using FT-ICR MS and proposed suggestions for current issues. This review will deepen our understanding of the chemical characterization of HOCs and their formation mechanisms and transformation at the molecular level in aquatic systems, facilitating the application of the state-of-the-art FT-ICR MS in environmental and geochemical research.

Pleomorphic Dematiomelanommayunnanense gen. et sp. nov. (Ascomycota, Melanommataceae) from grassland vegetation in Yunnan, China.

During a survey of microfungi associated with grasslands and related vegetation types from Yunnan Province in China, various ascomycetous and coelomycetous fungi were isolated. This study reports the discovery of four strains of ascomycetous and coelomycetous fungi from dead stalks of Hypericummonogynum L. (Hypericaceae) and Rubusparvifolius L. (Rosaceae) in the Zhaotong region of Yunnan Province, China. The isolates were characterized using multi-locus phylogenetic analyses and were found to represent a new monophyletic lineage in Melanommataceae (Pleosporales, Dothideomycetes). This new clade was named as Dematiomelanommayunnanense gen. et sp. nov. which consists of both sexual and asexual morphs. The sexual morph is characterized by globose to subglobose ascomata with a central ostiole, cylindrical asci with a pedicel and ocular chamber, and muriform, ellipsoidal to fusiform ascospores. The asexual morph has synanamorphs including both brown, muriform macroconidia and hyaline, round to oblong or ellipsoidal microconidia. These findings contribute to the understanding of fungal diversity in grasslands and related vegetation types in Yunnan Province, China.

Insights into the mechanisms involved in the fungal degradation of plastics.

Fungi are considered among the most efficient microbial degraders of plastics, as they produce salient enzymes and can survive on recalcitrant compounds with limited nutrients. In recent years, studies have reported numerous species of fungi that can degrade different types of plastics, yet there remain many gaps in our understanding of the processes involved in biodegradation. In addition, many unknowns need to be resolved regarding the fungal enzymes responsible for plastic fragmentation and the regulatory mechanisms which fungi use to hydrolyse, assimilate and mineralize synthetic plastics. This review aims to detail the main methods used in plastic hydrolysis by fungi, key enzymatic and molecular mechanisms, chemical agents that enhance the enzymatic breakdown of plastics, and viable industrial applications. Considering that polymers such as lignin, bioplastics, phenolics, and other petroleum-based compounds exhibit closely related characteristics in terms of hydrophobicity and structure, and are degraded by similar fungal enzymes as plastics, we have reasoned that genes that have been reported to regulate the biodegradation of these compounds or their homologs could equally be involved in the regulation of plastic degrading enzymes in fungi. Thus, this review highlights and provides insight into some of the most likely regulatory mechanisms by which fungi degrade plastics, target enzymes, genes, and transcription factors involved in the process, as well as key limitations to industrial upscaling of plastic biodegradation and biological approaches that can be employed to overcome these challenges.

Ultrastable Aluminum Nanoparticles with Enhanced Combustion Performance Enabled by a Polydopamine/Polyethyleneimine Nanocoating.

In national defense, aluminum nanoparticles (Al NPs) have better combustion performance than Al microparticles but are easily oxidized during processing, especially in oxidative liquids. Although some protective coatings have been reported, it is still challenging to obtain Al NPs stable in oxidative liquids (e.g., hot liquids) without scarifying combustion performance. Here, we report ultrastable Al NPs with enhanced combustion performance enabled by the crosslinked polydopamine/polyethyleneimine (PDA/PEI) nanocoating merely ∼15 nm in thickness and ∼0.24 wt % in mass. The Al@PDA/PEI NPs are fabricated by one-step rapid graft copolymerization of dopamine and PEI on Al NPs at room temperature. The formation mechanism of the nanocoating is discussed including reactions between dopamine and PEI and interactions of the nanocoating with Al NPs. The Al@PDA/PEI NPs show excellent stability in hot water, and the mechanism is interpreted by molecular dynamics simulation. The PDA/PEI nanocoating can also enhance the combustion heat and burning rate of Al NPs.

Up-regulation of ribosomal and carbon metabolism proteins enhanced pyrene biodegradation in fulvic acid-induced biofilm system.

The polycyclic aromatic hydrocarbons (PAHs) that enter the aqueous phase usually coexist with fulvic acid (FA). Therefore, we initiated this investigation to explore the influences of FA on bacterial biofilm formation and its potential to biodegrade pyrene (PYR), using electron microscopic techniques and isobaric tags for relative and absolute quantification (iTRAQ). Our results revealed that FA stimulated biofilm formation and enhanced the biodegradation of PYR. First, FA favored the three-dimensional proliferation of bacteria, with an OD590/OD600 value of up to 14.78, and the extracellular surfaces covered by a layer of biomaterials. Distinctive intracellular morphologies of texture and organization were accompanied by reduced inter-bacterial distances of less than 0.31 µm. The biofilms formed displayed interactions between FA and surficial proteins, as noted by band shifts for the C-O and CO groups. Strikingly, FA triggered the upregulation of 130 proteins that were either operational in biofilm formation or in metabolic adjustments; with the changes supported by the increasing intensity of free amino acids and the newly generated N-O bonds. The results above revealed that the enhanced biodegradation was related to the up-regulation of the proteins functioned for ribosomal and carbon metabolism, and the ultra-structural changes in FA-induced biofilm system.

Effect of γ-Fe2O3 nanoparticles on the composition of montmorillonite and its sorption capacity for pyrene.

Fe content and distribution on montmorillonite would probably enhance its sorption capacity for hydrophobic organic pollutants. Thus, Fe modified montmorillonites with different ratios of FeSO4·7H2O and Ca-montmorillonite were prepared. The results indicated that γ-Fe2O3 nanoparticles were not only generated at the montmorillonite surfaces, but that the γ-Fe2O3 also extended the edges of montmorillonite surfaces. The sorption capacities for pyrene were enhanced and even reached 834.79 µg g-1 with increase in ferrous iron content, but were then suppressed due to aggregation of γ-Fe2O3 on montmorillonite surfaces. Furthermore, pyrene was directly observed on γ-Fe2O3-montmorillonite surfaces with a lattice spacing parameter of approximately 0.27 nm, indicating that a new phase that mainly contained pyrene was generated during the sorption process. Additionally, after regenerating the γ-Fe2O3-montmorillonite composites, they could be reused for at least 5 cycles. It is therefore proposed that the prepared γ-Fe2O3-montmorillonite could be exploited as a potential green composite for remediation of hydrophobic organic pollutants in soil and sediment.

Fabrication of fluorescent magnetic Fe3O4@ZnS nanocomposites.

A novel Fe3O4@ZnS nanomaterial with fluorescent and superparamagnetic properties has been successfully fabricated via TOPO-TOP synthesis with an additional coordinating component (OAm). The adsorption of OAm on the preformed magnetite nanoparticles, which were prepared in phenyl ether with oleic acid and oleyl amine, played an essential role in directing the structure of the Fe3O4@ZnS composites. The obtained materials were characterized by FTIR, TEM, XRD, X-ray photoelectron spectroscopy (XPS), UV-vis, fluorescence spectrophotometer and VSM. The results indicated that the Fe3O4 nanoparticles were successfully combined with ZnS and the coating of ZnS can be controlled by adjusting the molar ratio of Fe3O4 to ZnS. The saturation magnetization values of Fe3O4, Fe3O4@ZnS (1:2) and Fe3O4@ZnS (1:5) nanoparticles are 57.0 emu g(-1), 44.4 emu g(-1) and 34.2 emu g(-1), respectively at 300 K and the nanocomposites exhibit better fluorescence without evident quenching. The combined magnetic and fluorescent properties endow the nanocomposites with great potential applications in "nano-conveyer-belt" platform technology for drug targeting, bioseparation, diagnostic analysis and so on.

Synthesis and antifungal activity of N-(substituted pyridinyl)-1-methyl(phenyl)-3-(trifluoromethyl)-1H-pyrazole-4-carboxamide derivatives.

A series of N-(substituted pyridinyl)-1-methyl(phenyl)-3-trifluoromethyl-1H-pyrazole-4-carboxamide derivatives were synthesized. All target compounds were characterized by spectral data (¹H-NMR, ¹³C-NMR, IR, MS) and elemental analysis and were bioassayed in vitro against three kinds of phytopathogenic fungi (Gibberella zeae, Fusarium oxysporum, Cytospora mandshurica). The results showed that some of the synthesized N-(substituted pyridinyl)-1-methyl-3-trifluoromethyl-1H-pyrazole-4-carboxamides exhibited moderate antifungal activities, among which compounds 6a, 6b and 6c displayed more than 50% inhibition activities against G. zeae at 100 µg/mL, which was better than that of the commercial fungicides carboxin and boscalid.

catena-Poly[[[2-(pyridin-2-yldisulfan-yl)pyridine-κN,S]copper(I)]-µ(1,5)-dicyanamido].

In the title compound, [Cu(C(2)N(3))(C(10)H(8)N(2)S(2))](n), the Cu(I) atoms are connected by bridging dicyanamide ligands, forming chains parallel to [100]. Each Cu(I) atom displays a tetra-hedral coordination environment, formed by one S atom and three N atoms from one 2-(pyridin-2-yldisulfan-yl)pyridine and two dicyanamide ligands. The crystal structure is stabilized by C-H⋯N hydrogen bonds, forming a three-dimensional network.