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An organo-photoredox catalyzed gem-difluoroallylation of glycine with α-trifluoromethyl alkenes via direct C(sp3)-H functionalization of glycine and C-F bond activation of α-trifluoromethyl alkenes has been described. As a consequence, a broad range of gem-difluoroalkene-containing unnatural amino acids are afforded in moderate to excellent yields. This reaction exhibits multiple merits such as readily available starting materials, broad substrate scope, and mild reaction conditions. The feasibility of this reaction has been highlighted by the late-stage modification of several peptides as well as the improved in vitro antifungal activity of compound 3v toward Valsa mali compared to that with commercial azoxystrobin.
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Aminoácidos , Glicina , Alcenos , Peptídeos , CatáliseRESUMO
Per- and poly fluoroalkyl substances (PFASs) are often encountered with nonaqueous phase liquid (NAPL) in the groundwater at fire-fighting and military training sites. However, it is unclear how PFASs affect the dechlorination performance of sulfidized nanoscale zerovalent iron (S-nFe0), which is an emerging promising NAPL remediation agent. Here, S-nFe0 synthesized with controllable S speciation (FeS or FeS2) were characterized to assess their interactions with PFASs and their dechlorination performance for trichloroethylene NAPL (TCE-NAPL). Surface-adsorbed PFASs blocked materials' reactive sites and inhibited aqueous TCE dechlorination. In contrast, PFASs-adsorbed particles with improved hydrophobicity tended to enrich at the NAPL-water interface, and the reactive sites were re-exposed after the PFASs accumulation into the NAPL phase to accelerate dechlorination. This PFASs-induced phenomenon allowed the materials to present a higher reactivity (up to 1.8-fold) with a high electron efficiency (up to 99%) for TCE-NAPL dechlorination. Moreover, nFe0-FeS2 with a higher hydrophobicity was more readily enriched at the NAPL-water interface and more reactive and selective than nFe0-FeS, regardless of coexisting PFASs. These results unveil that a small amount of yet previously overlooked coexisting PFASs can favor selective reductions of TCE-NAPL by S-nFe0, highlighting the importance of materials hydrophobicity and transportation induced by S and PFASs for NAPL remediation.
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Ferro , Ferro/química , Poluentes Químicos da Água/química , Halogenação , Água Subterrânea/químicaRESUMO
The first patient, a 10-year-old girl, presented with pancytopenia and recurrent epistaxis, along with a history of repeated upper respiratory infections, café-au-lait spots, and microcephaly. Genetic testing revealed compound heterozygous mutations in the DNA ligase IV (LIG4) gene, leading to a diagnosis of LIG4 syndrome. The second patient, a 6-year-old girl, was seen for persistent thrombocytopenia lasting over two years and was noted to have short stature, hyperpigmented skin, and hand malformations. She had a positive result from chromosome breakage test. She was diagnosed with Fanconi anemia complementation group A. Despite similar clinical presentations, the two children were diagnosed with different disorders, suggesting that children with hemocytopenia and malformations should not only be evaluated for hematological diseases but also be screened for other potential underlying conditions such as immune system disorders.
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Anormalidades Múltiplas , Humanos , Feminino , Criança , Anormalidades Múltiplas/genética , Pancitopenia/etiologia , Pancitopenia/genética , DNA Ligase Dependente de ATP/genética , DNA Ligase Dependente de ATP/deficiência , Trombocitopenia/genética , Trombocitopenia/etiologia , CitopeniaRESUMO
Mercury (Hg) pollution is a well-recognized global environmental and health issue and exhibits distinctive persistence, neurotoxicity, bioaccumulation, and biomagnification effects. As the largest global Hg reservoir, the Hg cumulatively stored in soils has reached as high as 250-1000 Gg. Even more concerning is that global soil-rice systems distributed in many countries have become central to the global Hg cycle because they are both a major food source for more than 3 billion people worldwide and the central bridge linking atmospheric and soil Hg circulation. In this review, we discuss the form distribution, transformation, and bioavailability of Hg in soil-rice systems by focusing on the Hg methylation and demethylation pathways and distribution, uptake, and accumulation in rice plants and the effects of Hg on the community structure and ecological functions of microorganisms in soil-rice systems. In addition, we clarify the mechanisms through which commonly used humus and biochar organic amendments influence Hg and its environmental effects in soil-rice systems. The review also elaborates on the advantages of sulfur-modified biochars and their critical role in controlling Hg migration and bioavailability in soils. Finally, we provide key information about Hg pollution in soil-rice systems, which is of great significance for developing appropriate strategies and mitigation planning to limit Hg bioconcentration in rice crops and achieving key global sustainable development goals, such as the guarantee of food security and the promotion of sustainable agriculture.
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Mercúrio , Compostos de Metilmercúrio , Oryza , Poluentes do Solo , Humanos , Mercúrio/análise , Compostos de Metilmercúrio/metabolismo , Solo/química , Oryza/metabolismo , Agricultura , Poluentes do Solo/análiseRESUMO
Wastewater irrigation is used to supplement agricultural irrigation because of its benefits and freshwater resource scarcity. However, whether wastewater irrigation for many years affects the electron transfer capacity (ETC) of natural organic matter in soil remains unclear, and organic matter could influence the decomposition and mineralization of substances with redox characteristics in soil through electron transfer, ultimately affecting the soil environment. The composition of soil humic substances (HS) is highly complex, and the effects of soil humic acid (HA) and fulvic acid (FA) on ETC is poorly understood. In this study, we separately evaluated the responses of the electron-accepting capacity (EAC) and electron-donating capacity (EDC) of soil HA and FA in agricultural fields to various durations of wastewater irrigation. Results showed that the EAC of HA and FA increased significantly with increasing the duration of wastewater irrigation. When wastewater irrigation lasted for 56 years, the EAC of HA showed a higher increment (590 %) than that of FA (223 %). The EDC of soil HA and FA, conversely, decreased compared to the control, with the highest reduction of 35.6 % for HA and 65.9 % for FA. Specifically, the EDC of HA gradually decreased starting from 29 years of wastewater irrigation, whereas the decrease in the EDC of FA exhibited no clear pattern in relation to the duration of wastewater irrigation. Increased soil organic matter and total nitrogen content under long-term wastewater irrigation led to an increase in sucrase and phosphatase activities, along with an increase in EAC and a decrease in EDC of HS. This suggests that soil enzyme activities may ultimately lead to changes in ETC. The results of this research provide practical insights into the redox system in soil and its driving role in soil organic matter transformation and nutrient cycling under wastewater irrigation.
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Phthalate esters (PAEs) are added to various products as plasticizers. Plastic waste containing PAEs enters landfills as they age with use. However, the influence of microenvironmental changes on the occurrence of PAEs during landfill stabilization is still unknown. In this study, we evaluated the relationship between the physical and chemical properties of leachate, the structure of bacterial communities and the chemical structure of dissolved organic matter (DOM), and the occurrence of PAEs and the mechanism underlying their responses to changes. Landfill leachate in different stabilization states had high Cl- and NH4+ contents and its metal element (Cr, Pb, and Zn) contents generally decreased with the increase in landfill ages. Proteobacteria, Bacteroidetes, and Firmicutes were important phyla and had an average relative abundance of 68.63%. The lignin/carboxylate-rich alicyclic molecule structure was the main component of DOM (56%-64%). Of the 6-priority controlled PAEs in leachate, di-n-butyl phthalate was the most abundant (1046 µg L-1), while butyl phthalate was not detected. The results showed that pH, the relative abundance of Chloroflexi, and the value of SUVA254 can directly influence the occurrence of PAEs in leachate. The positive and negative effects vary depending on the PAE content and molecular weight. DBP and DEHP have higher environmental risks in the aquatic system. These results are intended to provide a scientific basis for the evolutionary characterization of the microenvironment in complex environmental systems and the control of novel contaminants, such as PAEs.
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Phthalates (PAEs) are added to various products as a plasticizer. As these products age and are disposed of, plastic waste containing PAEs enters the landfill. The landfill environment is complicated and can be regarded as a "black box". Also, PAEs do not bind with the polymer matrix. Therefore, when a series of physical chemistry and biological reactions occur during the stabilization of landfills, PAEs leach from waste and migrate to the surrounding environmental media, thereby contaminating the surrounding soil, water ecosystems, and atmosphere. Although research on PAEs has achieved progress over the years, they are mainly concentrated on a particular aspect of PAEs in the landfill; there are fewer inquiries on the life cycle of PAEs. In this study, we review the presence of PAEs in the landfill in the following aspects: (1) the main source of PAEs in landfills; (2) the impact of the landfill environment on PAE migration and conversion; (3) distribution and transmedia migration of PAEs in aquatic ecosystems, soils, and atmosphere; and (4) PAE management and control in the landfill and future research direction. The purpose is to track the life cycle of PAEs in landfills, provide scientific basis for in-depth understanding of the migration and transformation of PAEs and environmental pollution control in landfills, and new ideas for the sustainable utilization of landfills.
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We describe the synthesis, crystal structure and semiconducting properties of a number of hexacyanidometallates with the formula A2[MFe(CN)6]·xH2O (A = Na, K; M = Mg, Ca, Sr and Ba). All crystal structures were studied via single-crystal or powder X-ray diffraction. The unexpectedly low-symmetric structures in these ferrocyanides are described and contrasted with analogous transition-metal compounds which have been reported to be strictly or nearly cubic. The amount of crystal water in the structure for powder samples was determined by the thermogravimetric analysis (TGA), supported by IR and Raman spectroscopy. Electronic-structure calculations of K2[MgFe(CN)6] and K2[CaFe(CN)6] are compared with experimental UV-Vis measurements. The large band gaps by advanced theory indicate that the smaller experimental band gaps are due to surface effects of impurity states. Mott-Schottky curves of K2[MgFe(CN)6], K2[CaFe(CN)6] and K2[BaFe(CN)6]·3H2O exhibit positive slopes, which characterizes these compounds as n-type semiconductors.
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Herb medicines are popular for safe application due to being a source of natural herbs. However, how to deliver them in an efficacious and convenient manner poses a big challenge to researchers. In this study, a new concept is demonstrated that the electrospun polymer-based hybrid films can be a platform for promoting the delivery of a mixture of active herb extract, i.e., Lianhua Qingwen Keli (LQK), also a commercial traditional Chinese patent medicine. The LQK can be co-dissolved with the filament-forming polymeric polyvinylpyrrolidone K60 and a sweeter sucralose to prepare an electrospinnable solution. A handheld electrospinning apparatus was explored to transfer the solution into solid nanofibers, i.e., the LQK-loaded medicated films. These films were demonstrated to be composed of linear nanofibers. A puncher was utilized to transfer the mat into circular membrane a diameter of 15 mm. Two self-created methods were developed for disclosing the dissolution performances of the electrospun mats. Both the water droplet experiments and the wet paper (mimic tongue) experiments verified that the hybrid films can rapidly disintegrate when they encounter water and release the loaded LQK in an immediate manner. Based on the reasonable selections of polymeric excipients, the present protocols pave a way for delivering many types of active herb extracts in an effective and convenient manner.
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Alcohols are ubiquitous in chemistry and are native functionalities in many natural products and bioactive molecules. As such, a strategy that utilizes hydroxy-containing compounds to develop bond disconnection and bond formation process would achieve molecular diversity. Herein we utilize bench-stable N-alkoxyphthalimides prepared from alcohols to couple with glycine derivatives via radical process under visible light irradiation, providing a variety of unnatural amino acid (UAA) and peptide derivatives. The approach allows to rapidly deconstruct molecular complexity via ß-fragmentation such as saclareolide, ß-pinene and camphor and provides products with unique scaffolds, which show inhibition toward the pathogenic fungi growth.
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Produtos Biológicos , Fabaceae , Aminoácidos , Cânfora , GlicinaRESUMO
The spatial distribution of phthalate acid esters (PAEs) in sediments of the Jiaozhou Bay and its relationships with anthropogenic activities and environmental variables were investigated in this work. Thirteen PAEs were prevalent in sediments and the total PAE concentrations ranged from 462.1 to 15,133.2 µg/kg. The PAE concentrations increased northeastward and northwestward from the bay mouth in saddle shapes and the highest concentrations were located in the northeastern region according to the spatial distribution patterns generated by geographic information systems. The rivers were the main routes for transporting pollutants into the bay and terrigenous PAEs diluted offshore, so the PAE distribution in sediments was originated from anthropogenic activity intensity. There were strong positive correlations among PAEs with each other, except for di-n-octyl phthalate, and the average residence time (ART) exerted a significant positive impact on the PAE concentrations by Pearson correlation and redundancy analysis. The dibutyl phthalate and di-(2-ethylhexyl) phthalate had high risks to organisms in the northeast and west regions according to the environmental risk limits and risk quotients. The results might provide new insights into the PAE researches and supply information for environmental management and remediation.
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Ésteres/análise , Ácidos Ftálicos/análise , Baías , China , Dibutilftalato/análise , Monitoramento Ambiental , Sedimentos Geológicos , RiosRESUMO
Spatial distribution and ecological risks of phthalate acid esters (PAEs) in sediments of the Laizhou Bay were investigated, and the relationships of PAEs with human activities and geochemical variables were studied in this work. Thirteen detectable PAEs were widespread occurrence, and the total PAE concentrations ranged from 813.1 to 11,975.6 µg/kg dry weight in sediments of the Laizhou Bay. Di-(2-ethylhexyl) phthalate (DEHP) and di-butyl phthalate (DBP) were predominant and accounted for 51.9% of ΣPAEs. The major sources of PAEs with their characteristic PAE congeners or composition could be classified as riverine runoff from catchments of the Yellow River and the rivers Xiaoqing & Zhimai, and direct discharge from the west coast and Binhai Zone, according to continuous PAE spatial distribution patterns generated by GIS techniques. The concentrations of most PAEs gradually decreased from west inshore to east offshore in inverted S shapes, which was consistent with the tide field of the Laizhou Bay. There are negative correlations between sediment depth and all PAEs, and nine PAEs exhibited negative correlations with salinity using Pearson correlation analysis. Depth and salinity exerted negative influence on PAEs (contributions of 55.8% and 32.0%, respectively) according to redundancy analysis. The DBP concentrations of 15.1% sites exceeded the ERLs and only one site had the DEHP concentration exceeded environmental risk limits. The DBP risk quotient values of 11.3% (for algae), 3.8% (for crustaceans) and 43.4% (for fish) sites exceeded 1, and most of these sites are near to four major sources. These results might benefit the implementation of effective environmental management and remediation practices.