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1.
J Hazard Mater ; 402: 123498, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32712366

RESUMO

N-doped nanoporous carbon (NC) with two-dimensional structure derived from Zn-ZIF-L via KCl exfoliation and carbonization at different temperature were prepared for adsorptive removal of tetracycline (TC). Characterizations revealed the effective dopant of N atoms and low degree of graphitization with more defects related to the enhanced adsorption capacity of the NC materials. Benefiting from the huge surface area (2195.57 m2 g-1), high porosity (1.34 cm3 g-1) and accessible sheeting structure, the NC-800 exhibited its fast and efficient adsorption of TC in 60 min. Meantime, the maximum adsorption of TC could reach 347.06 mg g-1. Effects of pH, humic acid (HA) and ionic strength (Na+, Ca2+) were studied along with the interactions among influencing factors investigated by response surface model (RSM). By optimizing experimental conditions from RSM, the adsorption capacity could increase to 427.41 mg g-1. Additionally, electrostatic interaction and hydrogen bond interaction might play a dominating role in adsorption reaction. The NC-800 could maintain a high adsorption level after four cycles. Therefore, the NC-800 with great adsorptive property and reusability could be considered as an effective adsorbent with promising potential in applications for water treatment.

2.
J Colloid Interface Sci ; 581(Pt A): 195-204, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32771731

RESUMO

Compared with the transition metal induced homogeneous catalytic system, the heterogeneous catalytic system based on transition metal-doped metal organic frameworks (MOFs) were stable for the efficient utilization of transition metal and avoiding the metal leaching. The aim of this work is to synthesize Co-doped MIL-53(Al) by one-step solvent thermal method and use it to activate peroxymonosulfate (PMS) to remove tetracycline (TC) in water. The successful synthesis of Co-MIL-53(Al) samples was demonstrated by XDR, SEM and FTIR characterizations. The 25% Co-MIL-53(Al)/PMS system showed the optimal TC removal effect compared to the PMS alone and MIL-53(Al)/PMS system. The catalytic performances of Co-MIL-53(Al)/PMS system in conditions of different pH, co-existing substances and water bodies were investigated. Quenching experiment and electron paramagnetic resonance (EPR) showed that the degradation mechanism by Co-MIL-53(Al) activation PMS was mainly attributed to sulfate radical (SO4•-) and singlet oxygen (1O2) non-radical. The degradation intermediates of TC were also identified and the possible degradation pathways were proposed. Co-MIL-53(Al) showed good activity after four cycles. These findings demonstrated that Co-MIL-53(Al) can be a promising heterogeneous catalyst for activating PMS to degrade TC.

3.
Sci Total Environ ; 741: 140470, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32886967

RESUMO

Chemical compositions of non-refractory submicron aerosol (NR-PM1) were measured via an Aerodyne Aerosol Chemical Speciation Monitor at the coastal city Xiamen during the 2017 BRICS summit from August 10 to September 10. Mean hourly concentration of NR-PM1 was 13.55 ± 8.83 µg m-3 during the study period, decreasing from 18.83 µg m-3 before-BRICS to 13.02 µg m-3 in BRCIS I and 8.42 µg m-3 in BRICS II. Positive matrix factor analyses resolved four organic aerosols (OA): a hydrocarbon-like OA (HOA, 14.78%), a cooking-related OA (COA, 28.21%), a biomass burning OA (BBOA, 18.00%), and an oxygenated OA (OOA, 39.22%). The contributions of local pollutants like nitrate and HOA reduced, while the proportions of sulfate and OOA increased during the control episodes. The diurnal patterns of NR-PM1 species and OA components in each episode were characterized. The results showed that BC, nitrate, COA, and HOA had peaks in the morning and evening, which became less obvious under the emission control. Moreover, the diurnal variations of all species in Ep 3 with emission control were much flatter due to the effect of transport. Backward trajectories analysis confirmed the long-range transport of air masses from the continent, which resulted in the high proportions of sulfate (43.69%) and OOA (50.28%) in Ep 3. Our study implies the significant effect of emission control on reducing primary pollutants, but the formation of particles during the long-range transport need to be paid more attention when set the air quality control strategies in coastal cities.

4.
Chin Med J (Engl) ; 133(17): 2090-2097, 2020 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-32784334

RESUMO

BACKGROUND: TOSO, also named Fas inhibitory molecule 3 (FAIM3), has recently been identified as an immunoglobulin M (IgM) Fc receptor (FcµR). Previous studies have shown that TOSO is specifically over-expressed in chronic lymphocytic leukemia (CLL). However, the functions of TOSO in CLL remain unknown. The B-cell receptor (BCR) signaling pathway has been reported to be constitutively activated in CLL. Here, we aimed to investigate the functions of TOSO in the BCR signaling pathway and the pathogenesis of CLL. METHODS: We over-expressed TOSO in B-cell lymphoma cell lines (Granta-519 and Z138) by lentiviral transduction and knocked down TOSO by siRNA in primary CLL cells. The over-expression and knockdown of TOSO were confirmed at the RNA level by polymerase chain reaction and protein level by Western blotting. Co-immunoprecipitation with TOSO antibody followed by liquid chromatography coupled with tandem mass spectrometry (IP/LCMS) was used to identify TOSO interacting proteins. Western blotting was performed to detect the activation status of BCR signaling pathways as well as B-cell lymphoma 2 (BCL-2). Flow cytometry was used to examine the apoptosis of TOSO-over-expressing B lymphoma cell lines and TOSO-down-regulated CLL cells via the staining of Annexin V and 7-AAD. One-way analyses of variance were used for intergroup comparisons, while independent samples t tests were used for two-sample comparisons. RESULTS: From IP/LCMS, we identified spleen tyrosine kinase (SYK) as a crucial candidate of TOSO-interacting protein and confirmed it by co-immunoprecipitation. After stimulation with anti-IgM, TOSO over-expression increased the phosphorylation of SYK, and subsequently activated the BCR signaling pathway, which could be reversed by a SYK inhibitor. TOSO knockdown in primary CLL cells resulted in reduced SYK phosphorylation as well as attenuated BCR signaling pathway. The apoptosis rates of the Granta-519 and Z138 cells expressing TOSO were (8.46 ±â€Š2.90)% and (4.20 ±â€Š1.21)%, respectively, significantly lower than the rates of the control groups, which were (25.20 ±â€Š4.60)% and (19.72 ±â€Š1.10)%, respectively (P < 0.05 for both). The apoptosis rate was reduced after knocking down TOSO in the primary CLL cells. In addition, we also found that TOSO down-regulation in primary cells from CLL patients led to decreased expression of BCL-2 as well as lower apoptosis, and vice versa in the cell line. CONCLUSIONS: TOSO might be involved in the pathogenesis of CLL by interacting with SYK, enhancing the BCR signaling pathway, and inducing apoptosis resistance.

5.
J Colloid Interface Sci ; 580: 470-479, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32711198

RESUMO

Herein, Mn-doped MIL-53(Fe) were fabricated via one-pot solvothermal method and used for peroxymonosulfate (PMS) activation towards tetracycline (TC) degradation from aqueous solution. The characterizations of SEM, FTIR and XRD were utilized to reveal the morphology and structure of the materials. The results showed that Mn-MIL-53(Fe)-0.3 displayed the optimal catalytic performance, the removal efficiency of TC could reach 93.2%. Moreover, the catalytic activity of Mn-MIL-53(Fe) towards TC under different initial pH values, co-existing anions (Cl-,CO32- and SO42-) and humic acid (HA) were investigated. The results of thermodynamic experiment suggested that the catalytic process was endothermic. In addition, integrated with capture experiments results and the characterization results of electron paramagnetic resonance (EPR), which revealed that SO4·- and HO- were the reactive radicals involving in the reaction. More importantly, the possible activation mechanism was discussed in detail based on the X-ray photoelectron spectroscopy results. The active species were generated by the active sites of Fe(II) and Mn(II) on Mn-MIL-53(Fe) effectively activated PMS. Furthermore, the degradation intermediates and possible degradation pathway were investigated by LC-MS. Finally, the catalyst also showed good performance in actual wastewater and demonstrated good recyclability. The Mn-MIL-53(Fe)/PMS system exhibited a promising application prospect for antibiotic-containing waste water treatment.

6.
iScience ; 23(7): 101294, 2020 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-32623339

RESUMO

Reliable and sensitive detection of lipase activity is essential for the early diagnosis and monitoring of acute pancreatitis or progression of digestive diseases. However, the available fluorescent probes for detection of lipase activity are only implemented in a hexane-water two-phase system due to the nature of heterogeneous catalysis of lipase, thus limiting their applications in direct imaging of lipase activity in living cells and tissues. Here we designed and synthesized a "turn on" fluorescent probe CPP based on self-assembled micelles for hydrolysis of lipase. The CPP probe exhibits high selectivity and excellent sensitivity for the detection of lipase in such a homogeneous system and is successfully applied for monitoring lipase activity in pancreatic AR42J cells, tissues, and serums. Taken together, the fluorescent CPP probe not only provides a tool for diagnostic potential in pancreatic disease but also demonstrates an application potential for micelle self-assembly-based development of biological probes.

7.
J Pharm Biomed Anal ; 188: 113383, 2020 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-32502956

RESUMO

This study aimed to identify the antiplatelet aggregation quality markers of Salvia yunnanensis (SY) based on an integrated approach. The effects of SY methanol extracts on platelet aggregation were measured to evaluate their in vitro biological activity. Chemical composition differences were determined by HPLC. Molecular docking methods were used to assess the action mechanism of the potential active compounds and target proteins in SY. The results showed that 12 batches of SY samples inhibited platelet aggregation. Sodium danshensu, protocatechuic aldehyde, rutin, rosmarinic acid, salvianolic acid B, dihydrotanshinone I, tanshinone I, cryptotanshinone, and tanshinone IIA components were identified using chemical fingerprints. Multivariate statistical analysis indicated that cryptotanshinone, dihydrotanshinone I, tanshinone I, tanshinone IIA, and rosmarinic acid may have been the active components for antiplatelet aggregation, and molecular docking showed that these five components could combine with P2Y12 protein on platelets. Furthermore, platelet aggregation inhibition activity of the five monomers was verified separately and it was obvious that cryptotanshinone and rosmarinic acid inhibited platelet aggregation. Therefore, cryptotanshinone and rosmarinic acid may be the quality markers of SY. This report describes a comprehensive, scientific, and feasible method for SY quality evaluation and provides a preliminary scientific basis for applying the antithrombotic activity of SY.

8.
J Histotechnol ; 43(3): 125-134, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32314671

RESUMO

Adipose-derived mesenchymal stem cells (ADSC) are adult pluripotent cells and important resources for cell-based therapies of animals. There are presently different kinds of somatic cells used as donor cells for clone successfully. However, studies on somatic cell nuclear transplantation (SCNT) using ADSC as donor cells from Mongolian sheep have not been reported up to now. This study tested optimal methods of isolating, purifying, and proliferating Mongolian sheep ADSC, and determine their multiple differentiation potentiality. Adipose tissue was removed from approximately 2-year-old sheep and ADSC were harvested by pancreatic enzyme decomposition and adherent culture method. The growth curves of the Passages 1, 5, and 10 cultures were plotted and the exponential growth was determined as a population doubling time of 34.1 h. The expression of OCT4, SOX2, and NANOG genes were increased at Passage 3 (P3) as seen by reverse transcription polymerase chain reaction (RT-PCR) analysis. ADSC from Passage 3 were induced to undergo neurogenesis and form cardiomyocytes and pancreatic islet-like cells under inductive environments in vitro. The differentiation properties of cardiomyocytes and islet-like cells were confirmed by histological staining with toluidine blue, periodic acid-Schiff, and dithizone. The expression of specific genes in these cells were also detected by RT-PCR. Our study results confirm that isolated cells were indeed ADSC and may provide valuable materials for somatic cell clone and transgenic research.

9.
Sci Total Environ ; 724: 138248, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32247117

RESUMO

In this work, we investigated the impact of iron nanoparticle, including magnetite nanoparticles (Fe3O4 NPs) and nanoscale zero-valent iron (nZVI), on the anaerobic digestion (AD) performance. Moreover, the evolutions of antibiotic resistance genes (ARGs), class 1 integrons-integrase (intI1) and potential hosts of ARGs were also investigated. The optimal addition of Fe3O4 NPs and nZVI to promote methane production was 0.5 g/L and 1 g/L, which led to 22.07% and 23.02% increase in methane yield, respectively. The degradation rate of organic matter was also enhanced with the addition of Fe3O4 NPs or nZVI. The results of high-throughput sequencing showed that the reactors with iron NPs exhibited significant differences in microbial community structure, compared to the reactors with the non­iron NPs. Iron NPs have caused the relative abundance of the dominant bacteria (Proteobacteria, Firmicutes and Actinobacteria) generally decreased, while the dominant archaea (Euryarchaeota) increased in AD sludge. Quantitative PCR results revealed that iron NPs accelerated the reductions in total absolute abundance of ARGs, especially a beta-lactamase resistance encoded gene (blaOXA). Network analysis displayed that the attenuation of ARGs was mainly attributed to the decline of potential hosts (Proteobacteria, Firmicutes and Actinobacteria). Meanwhile, environmental factors (such as pH, soluble chemical oxygen demand and heavy metals) were also strongly correlated with ARGs.


Assuntos
Integrons , Nanopartículas , Anaerobiose , Antibacterianos/farmacologia , Resistência Microbiana a Medicamentos/efeitos dos fármacos , Genes Bacterianos/efeitos dos fármacos , Integrases/farmacologia , Ferro/farmacologia , Esgotos
10.
Cell Prolif ; 53(5): e12814, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32346990

RESUMO

OBJECTIVES: Increasing evidences suggest that inducing mesenchymal stem cells to differentiate into osteoblasts has been as an especially important component in the prevention and therapy for degenerative bone disease. Here, we identify a novel lncRNA, linc02349, which increases significantly during osteogenic differentiation. MATERIALS AND METHODS: Human umbilical cord-derived stem cells (hUC-MSCs) and dental pulp mesenchymal stem cells were used. Overexpression and knockdown of linc02349 in cell lines were generated using lentiviral-mediated gene delivery method. Bioinformatics prediction, Ago2-RIP assay and dual-luciferase reporter system were employed to examine miRNA which interacts with linc02349. The RNA FISH assay was performed to identify the subcelluar location of linc02349. Alizarin Red S staining, ALP staining and qPCR were applied to identify the osteogenic differentiation. The potential linc02349-regulated genes, miR-25-3p and miR-33b-5p, were explored by ChIP, RIP and Western blotting assays. Micro-CT was used to measure the osteogenic content in bone formation assay in vivo. RESULTS: Linc02349 overexpression improves osteogenic differentiation by in vitro and in vivo analysis. Mechanistically, linc02349 acts as a molecular sponge for miR-25-3p and miR-33b-5p to control expression abundance of SMAD5 and Wnt10b, respectively, which eventually activated Dlx5/OSX pathway and hence promoted osteogenic differentiation. In addition, we revealed that STAT3 interacts with linc02349 promoter region and positively regulates the linc02349 transcriptional activity. CONCLUSION: These findings identify that linc02349 modulates the osteogenic differentiation through acting as a sponge RNA of miR-25-3p and miR-33b-5p and regulating SMAD5 and Wnt10b, and proposed a new interaction between STAT3 and linc02349, which could be a potential target in the process the osteogenesis of hUC-MSCs for future clinical application.


Assuntos
Células-Tronco Mesenquimais/patologia , MicroRNAs/genética , Osteogênese/genética , RNA Longo não Codificante/genética , Cordão Umbilical/patologia , Diferenciação Celular/genética , Células Cultivadas , Células HEK293 , Humanos , Osteoblastos/patologia , Regiões Promotoras Genéticas/genética , Fator de Transcrição STAT3/genética , Transcrição Genética/genética
11.
Waste Manag ; 108: 1-12, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32334329

RESUMO

Insulating strategies are indispensable for laboratory-scale composting reactors, however, current insulation methods interfere with the aerobic fermentation behaviors related to composting. To address this issue, a centre-oriented real-time temperature compensation strategy was designed in this study. Five 9 L reactors (R1-R5) with different insulation strategies were used for the co-composting of dewatered sludge and Phragmites australis and compared. The process performance was assessed by monitoring the temperature, O2 and CO2 emissions, the physical-chemical properties of the composting materials were evaluated by measuring the organic matter (OM), carbon nitrogen ratio (C/N), pH, electrical conductivity (EC), and fluorescence excitation-emission matrix (EEM) spectra. And a 16S rDNA analysis was used to quantify the evolution of bacterial community. The main findings are as follows. Compared with R1 as a control, the insulating strategies can increase the maximum temperature and prolong the thermophilic phase of composting. Comparing R1 and R3 showed that real-time temperature compensation can better restore the real fermentation of the compost. The results showed that R5 had the best composting effect, reaching 69.8 °C, which was 25.1%, 29.7%, 19.3%, and 17.3% higher than R1, R2, R3, and R4, respectively, and remaining in the thermophilic phase for 4.24 d, which is 1.4, 1.5, 1.3, and 0.2 times longer than R1, R2, R3, and R4, respectively. Furthermore, it can significantly reduce the temperature difference between the centre and edge of the reactor, which improved the composting material allocation efficiency and composting process control accuracy, further providing a basis for the actual full-scale composting operation.


Assuntos
Compostagem , Bactérias , Nitrogênio , Esgotos , Solo , Temperatura
12.
FEMS Microbiol Ecol ; 96(4)2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32129838

RESUMO

Biochar, a valuable product from the pyrolysis of agricultural and forestry residues, has been widely applied as soil amendment. However, the effect of different types of biochar on soil microorganisms and associated biochemical processes in paddy soil remains ambiguous. In this study, we investigated the impact of biochars derived from different feedstocks (rice straw, orange peel and bamboo powder) on the dynamics of short-chain fatty acids (SCFAs), iron concentration and bacterial community in paddy soil within 90 days of anaerobic incubation. Results showed that biochar amendment overall inhibited the accumulation of SCFAs while accelerating the Fe(III) reduction process in paddy soil. In addition, 16S rRNA gene sequencing results demonstrated that the α-diversity of the bacterial community significantly decreased in response to biochar amendments at day 1 but was relatively unaffected at the end of incubation, and incubation time was the major driver for the succession of the bacterial community. Furthermore, significant correlations between parameters (e.g. SCFAs and iron concentration) and bacterial taxa (e.g. Clostridia, Syntrophus, Syntrophobacter and Desulfatiglans) were observed. Overall, our findings demonstrated amendment with different types of biochar altered SCFA profile, Fe(III) reduction and bacterial biodiversity in rice paddy soil.


Assuntos
Oryza , Poluentes do Solo , Carvão Vegetal , Ácidos Graxos Voláteis , Compostos Férricos , RNA Ribossômico 16S/genética , Solo , Poluentes do Solo/análise
13.
Chem Commun (Camb) ; 2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-32182322

RESUMO

Herein two unprecedented octanuclear Co8 clusters are presented, [Cl@Co8 (TEOA)4(CH3CN)Cl3] (1) and [S@Co8(DEOA)6(NCS)2] (2) (H3TEOA = triethanolamine, H2DEOA = diethanolamine), in which tetrahedral µ4-chloride and in situ generated octahedral µ6-sulfide are used as templates. In spite of them being derivatives of cubes, eight Co atoms in 1 consist of two co-centered tetrahedra of different sizes, whereas in 2 they appear as a rhombohedron formed via elongating a cube along the C3-axis direction. Strong intra-cluster antiferromagnetic interactions were found.

14.
J Vis Exp ; (156)2020 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-32065162

RESUMO

This report described sample preparation methods that scanning and transmission electron microscope observations, demonstrated by preparing appendages of the woodboring beetle, Chlorophorus caragana Xie & Wang (2012), for both types of electron microscopy. The scanning electron microscopy (SEM) sample preparation protocol was based on sample chemical fixation, dehydration in a series of ethanol baths, drying, and sputter-coating. By adding Tween 20 (Polyoxyethylene sorbitan laurate) to the fixative and the wash solution, the insect body surface of woodboring beetle was washed more cleanly in SEM. This study's transmission electron microscopy (TEM) sample preparation involved a series of steps including fixation, ethanol dehydration, embedding in resin, positioning using fluorescence microscopy, sectioning, and staining. Fixative with Tween 20 enabled penetrate the insect body wall of woodboring beetle more easily than it would had been without Tween 20, and subsequently better fixed tissues and organs in the body, thus yielded clear transmission electron microscope observations of insect sensilla ultrastructures. The next step of this preparation was determining the positions of insect sensilla in the sample embedded in the resin block by using fluorescence microscopy to increase the precision of target sensilla positioning. This improved slicing accuracy.


Assuntos
Besouros/ultraestrutura , Microscopia Eletrônica de Varredura/métodos , Microscopia Eletrônica de Transmissão/métodos , Manejo de Espécimes , Animais , Sensilas , Fixação de Tecidos
15.
J Pineal Res ; 68(3): e12635, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32012354

RESUMO

Embryo culture conditions are crucial as they can affect embryo quality and even offspring. Oviductal extracellular vesicles (EVs) long been considered a major factor influencing interactions between the oviduct and embryos, and thus its absence is associated with inferior embryonic development in in vitro culture. Herein, we demonstrated that melatonin is present in oviduct fluids and oviduct fluid-derived EVs. Addition of either EVs (1.87 × 1011 particles/mL) or melatonin (340 ng/mL) led to a significant downregulation of reactive oxygen species (ROS) and 5-methylcytosine (5-mC), as well as an increase in the blastocyst rate of embryos, which was inhibited by the addition of luzindole-a melatonin receptor agonist. A combination of EVs (1.87 × 1010 particles/mL) and melatonin (at 34.3 pg/mL) led to the same results as well as a significant decrease in the apoptosis index and increase in the inner cell mass (ICM)/trophectoderm (TE) index. These results suggest that an EV-melatonin treatment benefits embryonic development. Our findings provide insights into the role of EVs and melatonin during cell communication and provide new evidence of the communication between embryos and maternal oviduct.

16.
Bioresour Technol ; 304: 123016, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32078907

RESUMO

The effects of four conductive nanomaterials (nano-carbon powder, nano-Al2O3, nano-ZnO, nano-CuO) on sludge anaerobic digestion (AD) performance and microbial community were investigated through a 36-day fermentation experiment. Results showed that biogas production enhanced by 16.9% and 23.4% with nano-carbon powder and nano-Al2O3 added but decreased by 90.2% and 17.3% with nano-ZnO and nano-CuO. Total solids (TS) removal efficiency was increased by 38.73% and 27.11% with nano-carbon powder and nano-Al2O3 added but decreased by 70.67% and 43.70% with nano-ZnO and nano-CuO. Kinetic analysis indicated four conductive nanomaterials could shorten the lag phase of AD sludge with an average rate of 51.75%. 16S rRNA amplicon sequencing results demonstrated microbes such as Syntrophomonas and Methanosaeta were enriched in nano-carbon powder and nano-Al2O3 reactors. However, microbial community diversity and richness were both inhibited by adding nano-ZnO and nano-CuO. Redundancy analysis (RDA) revealed that genera belong to Firmicutes and Chloroflexi could conduce to methanogenesis process.


Assuntos
Microbiota , Nanoestruturas , Anaerobiose , Reatores Biológicos , Cinética , Metano , RNA Ribossômico 16S , Esgotos
17.
Sci Total Environ ; 707: 136194, 2020 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-31972916

RESUMO

The quasi-stationary front is a significant weather system which influences East Asia in spring. The air quality deteriorated along with the moist circumstance when the quasi stationary front dominated the area. Surface meteorological parameters, air pollutants and PM2.5 chemical species were observed during the air pollution episode. Liquid water content and aerosol acidity were calculated by thermodynamic model in order to investigate heterogeneous/aqueous reactions for secondary aerosol formation. The episode was divided into four stages based on quasi-stationary front influences. Hourly PM2.5 concentrations were up to 150.2 µg·m-3 while O3 concentrations reached the minimum value of 1.27 µg·m-3, indicating that the precursor gas NOx participated in the different reactions during the episode. Nitrate proportion of water-soluble inorganic ions was 42.2%. High concentrations of secondary inorganic aerosol ions and the high sulfur oxidation ratio (SOR) and nitrogen oxidation ratio (NOR) indicated the increasing conversions from SO2 and NOx to their corresponding particulate phases. Ratios of [NO3-]/[SO42-] and [NH4+]/[SO42-] in the four stages declared that nitrate formation preferred heterogeneous conversions. A series of liquid water content (LWC) fitting equations between relative humidity and inorganic ions were conducted to verify heterogeneous aqueous reactions of NO2 and secondary nitrate formation. The results of this study highlighted the significance of LWC and chemical reactions associated with acidity during the specific synoptic situation in South China.

18.
ChemSusChem ; 13(3): 438, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-31961486

RESUMO

Invited for this month's cover is the group of Liangfang Zhu and Changwei Hu at Sichuan University. The image shows a general understanding on the solvent-controlled formation of oligomers (the possible precursors of humins) accompanying with formation of small-molecular carboxylic acids as by-products in the initial reaction stage of fructose dehydration. The Full Paper itself is available at 10.1002/cssc.201902309.

19.
ChemSusChem ; 13(3): 501-512, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-31557412

RESUMO

The degradative condensation of hexose, which originates from the C-C cleavage of hexose and condensation of degraded hexose fragment, is one of the possible reaction pathways for the formation of humins in hexose dehydration to 5-hydroxymethylfurfural (HMF). Herein, the impacts of several polar aprotic solvents on the degradative condensation of fructose to small-molecule carboxylic acids and oligomers (possible precursors of humins) are reported. In particular, a close relationship between the tautomeric distribution of fructose in solvents and the mechanism of degradative condensation is demonstrated. Typically, α-fructofuranose in 1,4-dioxane and acyclic open-chain fructose in THF favor the conversion of fructose to formic acid and oligomers; α-fructopyranose in γ-valerolactone or N-methylpyrrolidone favors levulinic acid and oligomers, whereas ß-fructopyranose in 4-methyl-2-pentanone favors acetic acid and corresponding oligomers. This close correlation highlights a general understanding of the solvent-controlled formation of oligomers, which represents an important step toward the rational design of effective solvent systems for HMF production.

20.
Talanta ; 206: 120196, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514893

RESUMO

Nitroxyl (HNO), generated from nitric oxide (NO) in biological system, plays distinct biological roles in physiological process, but the role of endogenous HNO in biosystems still remains unclear, because of lacking of specific and sensitive detector to monitor HNO in real time. The conventional methods indicate the level of HNO through detecting the ultimate product nitrous oxide (N2O) of HNO dimerization and dehydration, which could easily result in inaccurate data. Therefore, developing an assay that can directly apply to detect HNO is of significance for understanding the function mechanism of HNO in biological system. In this study, we describe a near-infrared fluorescent probe 4-(2-(4-(dicyanomethylene)-4H-chromen-2-yl)vinyl) phenyl-2-(diphenylphosphanyl)-benzoate (CPN) that employs (2-(4-hydroxystyryl) -4H-chromen-4-ylidene) malononitrile (CP-OH) as a fluorophore and 2-(diphenylphosphino) benzoate as a recognition group. This probe, CPN, shows rapid-response to HNO which compared to other current probes. The fluorescent intensity reaches plateau in 20 min in vitro and in 2 min in vivo, respectively, which is important to monitor dynamic and transient state of HNO in biological system. In addition, CPN probe with a large Stokes' shift (150 nm) and near-infrared emission (700 nm) that is suitable for biological imaging. This probe has a potential of elucidating the biological function of HNO in biosystem.


Assuntos
Corantes Fluorescentes/química , Nitrilos/química , Óxidos de Nitrogênio/análise , Compostos Organofosforados/química , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/toxicidade , Células HeLa , Humanos , Microscopia Confocal/métodos , Microscopia de Fluorescência/métodos , Nitrilos/síntese química , Nitrilos/toxicidade , Compostos Organofosforados/síntese química , Compostos Organofosforados/toxicidade
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