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1.
Anal Chim Acta ; 1189: 339254, 2022 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-34815033

RESUMO

Sulfolane is explored as a novel stationary phase for use in analytical separations by capillary column gas chromatography with flame ionization detection (GC-FID). Stainless steel capillaries were found to provide a good substrate for coating and retaining a sulfolane phase, whereas fused silica tubing did not perform well for this. In general, the phase was found to be stable for several hours of use when using elevated carrier gas pressures (90 psi) and a small restriction (25 µm I.D. tubing) at the outlet. This normally provided good performance at temperatures up to about 200 °C with very little background interference in the FID. Given its separation properties, a short 2 m × 100 µm I.D. column was found to be preferable for most separations in this study. Measurements indicated the coating procedure yielded a sulfolane film near 4 µm thick on this column, which produced 4400 plates for benzene with a sample capacity near 30 µg. The sulfolane phase yielded good retention and peak shape for many analytes including alkanes, aromatics, alcohols, bases, sulfides, phosphites, thiols, and others. Compared to longer conventional GC columns, the relatively short sulfolane column was found to offer improved selectivity in the separation of unsaturated, aromatic, and alkane test analytes. As such the method was successfully applied to the analysis of aromatics in gasoline headspace. Results suggest that sulfolane could be a potentially useful stationary phase to further explore in GC separations.


Assuntos
Alcanos , Tiofenos , Cromatografia Gasosa , Ionização de Chama
2.
J Environ Manage ; 301: 113933, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34731951

RESUMO

The long-alkanes biodegradation rate was generally found slow during widely used pre-oxidation combined with biodegradation for oil contamination treatment, resulting in long and unsustainable removal. In this study, different chitosan content was used to produce iron catalysts for pre-oxidation, and nutrients were added for the long-alkanes biodegradation experiment. Mechanism of Fenton pre-oxidation and improvement in the biodegradation rate of long-alkanes were studied by analyzing the change in organic matter and bacterial community structure, the amount and activity of bacteria in the biological stage, and the degradation amount long-alkanes hydrocarbon before and after pre-oxidation. Results showed that the destruction of bacteria greatly reduced when hydroxyl radical intensity decreased to 4.40 a.u.. Also, the proportion of humic acid-like was high (40.88%), and the community structure was slightly changed with the pre-oxidation for the fast biodegradation (FB) group. In the subsequent biodegradation, it was found that the degradation rate of each long-alkanes in the FB group increased significantly (C30: 4.18-8.32 mg/(kg·d)) with the increase of the degradation of long-alkanes (10-50%). Further studies showed that the high nutrient dynamics (6.05 mg/(kg·d)) of the FB group resulted in high bacteria performance rate (0.53 mol CO2 × log CFU/(104 g2 d)), which further accelerated the substrate transformation(41%). Therefore, the biodegradation rate of long-alkanes was increased (43.8 mg/(kg·d)) with the removal rate of long-alkanes of 76%. The half-life of long-alkanes for the FB group (64 d) was 33 d shorter than the slow biodegradation group (99 d). These results exhibited that pre-oxidation regulation can shorten the bioremediation cycle by improving the biodegradation rate of long-alkanes. This research has good engineering application value.


Assuntos
Alcanos , Petróleo , Bactérias , Biodegradação Ambiental , Hidrocarbonetos
3.
Chemosphere ; 287(Pt 2): 132147, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34492415

RESUMO

Pathogenic fungi have been used worldwide to control crop pests and are assumed to pose negligible threats to the survival of pollinators. Although eusocial stingless bees provide essential pollination services and might be exposed to these biopesticides in tropical agroecosystems, there is a substantial knowledge gap regarding the side effects of fungal pathogens on behavioural traits that are crucial for colony functioning, such as guarding behaviour. Here, we evaluated the effect of Beauveria bassiana on the sophisticated kin recognition system of Tetragonisca angustula, a bee with morphologically specialized entrance guards. By combining behavioural assays and chemical analyses, we show that guards detect pathogen-exposed nestmates, preventing them from accessing nests. Furthermore, cuticular profiles of pathogen-exposed foragers contained significantly lower amounts of linear alkanes than the unexposed ones. Such chemical cues associated with fungal conidia may potentially trigger aggression towards pathogen-exposed bees, preventing pathogen spread into and among colonies. This is the first demonstration that this highly abundant native bee seems to respond in a much more adaptive way to a potentially infectious threat, outweighing the costs of losing foraging workforce when reducing the chances of fungal pathogen outbreaks within their colonies, than honeybees do.


Assuntos
Agentes de Controle Biológico , Comportamento de Nidação , Alcanos , Animais , Abelhas , Fungos , Polinização
4.
Arch Microbiol ; 203(10): 5937-5950, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34599404

RESUMO

Mycoremediation is an important process that targets the removal of petroleum hydrocarbons by fungi. Fungi have advantages with their extensive enzymatic systems, rapid adaptation to toxic organic pollutants, and to adverse environmental conditions. In this study, the colorimetric method was used for the preliminary investigation of petroleum degradation with ten fungal strains. Petroleum degradation ability of spore suspension, live biomass (fungal pellet and disc) and cell-free culture supernatant of the potent A. ochraceus strain were investigated by gravimetric analysis. It was found that the fungal disc (94%) was more successful than the spore suspension (87%) in petroleum degradation under physiological conditions determined as pH:5.0, 1% of petroleum concentration, 5% (v/v) of inoculum concentration (with spore suspension) and 1 g/100 mL of inoculum amount (with fungal disc) and 7 days of the incubation period. The degradation rate constant and half-life period of spore suspension were calculated as 0.291 day-1 and t1/2 = 0.340 and of the fungal disc were 0.401 day-1 and t1/2 = 0.247. Although, 7.5% and 10% (v/v) concentration of cell-free culture supernatant achieved more than 80% petroleum removal, it was not as effective as a fungal disc. According to gas chromatography/mass spectrometry analysis, the fungal disc of A. ochraceus strain degraded long-chain n-alkanes such as C35 and C36 more effectively than n-alkanes in the range of C22-C34. The fact that the A. ochraceus NRRL 3174 strain has a high petroleum degradation capacity as well as being a potent biosurfactant producer will provide a different perspective to advanced mycoremediation studies.


Assuntos
Petróleo , Poluentes do Solo , Alcanos , Aspergillus ochraceus , Biodegradação Ambiental , Hidrocarbonetos
5.
J Chromatogr A ; 1657: 462556, 2021 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-34601256

RESUMO

Ionic liquid bonded polysiloxanes (PILs) are a class of polysiloxanes whose side chains contain ionic liquid (IL) moieties. They not only inherit the character of "dual nature" from ILs but also inherit the excellent film-forming ability and thermal stability from polysiloxanes. In this paper, the solvation parameter model is introduced to investigate the interaction characteristics of PILs. The experimental results show that the b values of PILs occur in a wider range than those previously reported for the stationary phases. The hydrogen bond acidity can be effectively adjusted by varying the ionic liquid content or substituents. Hindering the formation of the hydrogen-bonded networks and increasing the exposed hydrogens may be intrinsic to the strong hydrogen bond acidity of PILs. Subsequently, the separation performances of these PIL stationary phases were demonstrated by separating various mixed samples of aromatic isomers, dichloroanilines, substituted alkanes, alcohols, esters, etc. The results show that the PILs with strong hydrogen bond acidity have excellent selectivity performances for aromatic position isomers, alcohols, and substituted alkanes. This study is significant for understanding the hydrogen bond acidity and broadening the range of hydrogen bond acidity of ionic liquid stationary phases.


Assuntos
Líquidos Iônicos , Alcanos , Cromatografia Gasosa , Ligação de Hidrogênio , Siloxanas
6.
Appl Microbiol Biotechnol ; 105(21-22): 8019-8032, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34655320

RESUMO

Nitroalkanes such as nitromethane, nitroethane, 1-nitropropane (1NP), and 2-nitropropane (2NP), derived from anthropogenic activities, are hazardous environmental pollutants due to their toxicity and carcinogenic activity. In nature, 3-nitropropionate (3NPA) and its derivatives are produced as a defense mechanism by many groups of organisms, including bacteria, fungi, insects, and plants. 3NPA is highly toxic as its conjugate base, propionate-3-nitronate (P3N), is a potent inhibitor of mitochondrial succinate dehydrogenase, essential to the tricarboxylic acid cycle, and can inhibit isocitrate lyase, a critical enzyme of the glyoxylate cycle. In response to these toxic compounds, several organisms on the phylogenetic scale express genes that code for enzymes involved in the catabolism of nitroalkanes: nitroalkane oxidases (NAOs) and nitronate monooxygenases (NMOs) (previously classified as nitropropane dioxygenases, NPDs). Two types of NMOs have been identified: class I and class II, which differ in structure, catalytic efficiency, and preferred substrates. This review focuses on the biochemical properties, structure, classification, and physiological functions of NMOs, and offers perspectives for their in vivo and in vitro applications. KEY POINTS: • Nitronate monooxygenases (NMOs) are key enzymes in nitroalkane catabolism. • NMO enzymes are involved in defense mechanisms in different organisms. • NMO applications include organic synthesis, biocatalysts, and bioremediation.


Assuntos
Alcanos , Oxigenases de Função Mista , Oxigenases de Função Mista/genética , Filogenia
7.
J Chromatogr A ; 1658: 462611, 2021 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-34666270

RESUMO

This work presents the investigation of using the amphiphilic triblock copolymer composed of poly(ethylene oxide)(PEO)-poly(propylene oxide) (PPO)-poly(ethylene oxide) (PEO) (denoted as EPE) as the stationary phase for gas chromatographic (GC) analyses. The EPE capillary column exhibited moderate polarity and column efficiency of 4348 plates/m determined by naphthalene at 120 °C (k = 11.52). Different from the PEG and polysiloxane homopolymers, it showed high-resolution performance towards a wide range of aliphatic and aromatic isomers in terms of polarity and acid-base properties. Particularly, the EPE column displayed distinct advantages for separating the critical isomers of alkanes, anilines and phenols and the components of the lemon essential oil over the commercial PEG and polysiloxane columns. In addition, the EPE column exhibited excellent separation repeatability and reproducibility with the relative standard deviation (RSD) values in the range of 0.03% - 0.08% for run-to-run, 0.14% - 0.61% for day-to-day and 3.1% - 4.0% for column-to-column, respectively. Moreover, the EPE column was investigated in terms of thermal stability, the minimum allowable operating temperature (MiAOT) and sample loadability. Its application to GC-MS analysis of the essential oil demonstrated its feasibility for practical analyses. This work demonstrates the promising future of triblock copolymers as a new class of selective stationary phases for GC analyses, which is barely reported up to date. The findings of this work is of important value for fundamental researches and practical applications.


Assuntos
Óleos Voláteis , Alcanos/análise , Cromatografia Gasosa , Isomerismo , Reprodutibilidade dos Testes
8.
Environ Monit Assess ; 193(10): 633, 2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34490544

RESUMO

Diagnostic ratios and compound-specific isotopic analysis (CSIA) are two tools that can help identify and differentiate the petrogenic and biogenic sources of hydrocarbons found in environmental samples. The present study aims to evaluate the concentration and type of n-alkanes and isoprenoids found in the oligotrophic waters of the Gulf of Mexico (n = 14), and through the typical diagnostic ratios reported for n-alkanes and its carbon isotopic composition (δ13C) to establish and differentiate the possible source of the hydrocarbons. Additionally, crude oil samples (n = 10) extracted in the Gulf of Mexico were evaluated by CSIA as a possible source of hydrocarbons to the study area. We found that the CSIA of δ13C for n-alkanes (n-C11 to n-C30) and isoprenoids (pristane and phytane) found in the surface water samples varied from - 25.55 to - 37.59‰ and from - 23.78 to - 33.97‰ in the crude oil samples, values which are more related to petrogenic sources. An analysis of the δ13C for pristane vs. phytane suggests that only three surface water samples show an origin in common that those observed in crude oils of the Gulf of Mexico. A low incidence of odd- and even-numbered n-alkanes higher than n-C25 in the water samples indicate low to negligible presence of terrigenous sources into the area, which was supported by the carbon isotopic composition of the individual n-alkanes.


Assuntos
Petróleo , Poluentes Químicos da Água , Alcanos/análise , Isótopos de Carbono/análise , Monitoramento Ambiental , Sedimentos Geológicos , Golfo do México , Petróleo/análise , Terpenos , Poluentes Químicos da Água/análise
9.
J Hazard Mater ; 416: 126202, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492965

RESUMO

The present study was conducted to compare the efficiency of different microbial mixed-cultures consists of fifteen oil-degrading microorganisms with different combinations. The investigation was targeted toward the removal of 500 mg/l pyrene and 1% w/v tetracosane, as single compounds or mixture. Sequential Fungal-Bacterial Mixed-Culture (SMC) in which bacteria added one week after fungi, recorded 60.76% and 73.48% degradation for pyrene and tetracosane; about 10% more than Traditional Fungal-Bacterial Mixed-Culture (TMC). Co-degradation of pollutants resulted in 24.65% more pyrene degradation and 6.41% less tetracosane degradation. The non-specified external enzymes of fungi are responsible for initial attacks on hydrocarbons. Delayed addition of bacteria and co-contamination would result in higher growth of fungi which increases pyrene degradation. The addition of Rhamnolipid potently increased the extent of pyrene and tetracosane degradation by approximately 16% and 23% and showed twice better performance than Tween-80 in 20 times less concentration. The results indicated the importance of having sufficient knowledge on the characteristics of the contaminated site and its contaminants as well as oil-degrading species. Gaining this knowledge and using it properly, such as the later addition of bacteria (new method of mixed-cultures inoculation) to the contaminated culture, can serve as a promising approach.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Poluentes do Solo , Alcanos , Bactérias , Biodegradação Ambiental , Fungos , Hidrocarbonetos Policíclicos Aromáticos/análise , Pirenos , Microbiologia do Solo , Poluentes do Solo/análise
10.
Chem Commun (Camb) ; 57(77): 9807-9819, 2021 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-34486592

RESUMO

(1,n) annulation reactions using (de)-hydrogenative coupling with alcohols or diols represent a straightforward technique for the synthesis of cyclic moieties. Utilization of such renewable resources for chemical transformations in a one-pot manner is the main focus, which avoids generation of stoichiometric waste. Application of such (1,n) annulation approaches drives the catalysis research in a more sustainable way and generates dihydrogen and water as by-products. This feature article highlights the recent (from 2015 to March 2021) progress in the synthesis of stereo-selective cycloalkanes and cycloalkenes, saturated and unsaturated N-heterocycles (cyclic amine, imide, lactam, tetrahydro ß-carboline, quinazoline, quinazolinone, 1,3,5-triazines etc.) and other N-heterocycles with the formation of multiple bonds in a one pot operation. Mechanistic studies, new catalytic approaches, and synthetic applications including drug synthesis and post-drug derivatization, scope, and limitations are discussed.


Assuntos
Álcoois/química , Elementos de Transição/química , Alcanos/síntese química , Alcanos/química , Alcenos/síntese química , Alcenos/química , Catálise , Compostos Heterocíclicos/síntese química , Compostos Heterocíclicos/química , Hidrogenação , Estrutura Molecular
11.
Molecules ; 26(15)2021 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-34361724

RESUMO

Orchids are rich treasure troves of various important phytomolecules. Among the various medicinal orchids, Ansellia africana stands out prominently in the preparing of various herbal medicines due to its high therapeutic importance. The nodal explants of A. africana were sampled from asymbiotically germinated seedlings on basal Murashige and Skoog (MS) medium and were micropropagated in MS medium supplemented with 3% sucrose and 10 µM meta topolin (mT) + 5 µM naphthalene acetic acid (NAA) +15 µM indole butyric acid (IBA) + 30 µM phloroglucinol (PG). In the present study, the essential oil was extracted by hydrodistillation and the oleoresins by the solvent extraction method from the micropropagated A. africana. The essential oil and the oleoresins were analysed by Gas Chromatography (GC) and GC/MS (Mass spectrometry). A total of 84 compounds were identified. The most predominant components among them were linoleic acid (18.42%), l-ascorbyl 2,6-dipalmitate (11.50%), linolenic acid (10.98%) and p-cresol (9.99%) in the essential oil; and eicosane (26.34%), n-butyl acetate (21.13%), heptadecane (16.48%) and 2-pentanone, 4-hydroxy-4-methyl (11.13%) were detected in the acetone extract; heptadecane (9.40%), heneicosane (9.45%), eicosane (6.40%), n-butyl acetate (14.34%) and styrene (22.20%) were identified and quantified in the ethyl acetate extract. The cytotoxic activity of essential oil and oleoresins of micropropagated A. africana was evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium Bromide) assay on Vero cells compared to the standard drug doxorubicin chloride. The present research contains primary information about the therapeutic utility of the essential oil and oleoresins of A. africana with a promising future research potential of qualitative and quantitative improvement through synchronised use of biotechnological techniques.


Assuntos
Citotoxinas/isolamento & purificação , Óleos Voláteis/isolamento & purificação , Orchidaceae/química , Extratos Vegetais/isolamento & purificação , Plântula/química , Acrilatos/isolamento & purificação , Alcanos/isolamento & purificação , Animais , Ácido Ascórbico/isolamento & purificação , Sobrevivência Celular/efeitos dos fármacos , Chlorocebus aethiops , Cresóis/isolamento & purificação , Meios de Cultura/química , Meios de Cultura/farmacologia , Citotoxinas/farmacologia , Cromatografia Gasosa-Espectrometria de Massas , Hidroponia/métodos , Ácido Linoleico/isolamento & purificação , Extração Líquido-Líquido/métodos , Óleos Voláteis/farmacologia , Orchidaceae/metabolismo , Palmitatos/isolamento & purificação , Pentanóis/isolamento & purificação , Pentanonas/isolamento & purificação , Extratos Vegetais/farmacologia , Plantas Medicinais , Plântula/metabolismo , África do Sul , Estireno/isolamento & purificação , Células Vero , Ácido alfa-Linoleico/isolamento & purificação
12.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 29(4): 1028-1033, 2021 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-34362478

RESUMO

OBJECTIVE: To investigate the role of petroleum ether extract of Rhizoma Amorphophalli (SLG) in inhibiting proliferation and promoting apoptosis and differentiation of leukemia K562 cells. METHODS: K562 cells were processed by SLG and PD98059 which was the ERK signaling pathway blocker. Then cell vitality was tested by MTT. Cell apoptosis rate and positive percentage of antigen expression related with differentiation were detected by flow cytometry. The protein expression levels of ERK1/2 and pERK1/2 were detected by Western blot. RESULTS: The proliferation activity of K562 was reduced by 50, 100, 200 mg/L SLG in a concentration dependent manner (r=0.9997). The apoptosis rate and positive expression rate of CD11b, CD14 and CD42b which were related with differentiation were raised by SLG, as well as the expression of pERK1/2, while PD98059 could reverse the promoting effect of SLG on apoptosis and differentiation partially. CONCLUSION: SLG can inhibit the proliferation and promote apoptosis and differentiation of K562 cells through ERK signaling pathway.


Assuntos
Petróleo , Alcanos , Apoptose , Proliferação de Células , Humanos , Células K562 , Extratos Vegetais/farmacologia
13.
J Chem Inf Model ; 61(9): 4259-4265, 2021 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-34378385

RESUMO

The hydrogen abstraction reactions of the hydroxyl radical with alkanes play an important role in combustion chemistry and atmospheric chemistry. However, site-specific reaction constants are difficult to obtain experimentally and theoretically. Recently, machine learning has proved its ability to predict chemical properties. In this work, a machine learning approach is developed to predict the temperature-dependent site-specific rate constants of the title reactions. Multilayered neural network (NN) models are developed by training the site-specific rate constants of 11 reactions, and several schemes are designed to improve the prediction accuracy. The results show that the proposed NN models are robust in predicting the site-specific and overall rate constants.


Assuntos
Alcanos , Radical Hidroxila , Hidrogênio , Cinética , Aprendizado de Máquina
14.
Environ Sci Technol ; 55(17): 11859-11873, 2021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34378915

RESUMO

Toxicological data suggest a significant developmental toxicity of per- and polyfluoroalkyl substances (PFASs); however, evidence in humans remains inconclusive. Furthermore, the effects of prenatal exposure to PFASs on hormones in the growth hormone (GH)/insulin-like growth factor (IGF) axis of newborns remain largely unclear. We aimed to investigate the associations of prenatal exposure to PFASs with the neonatal birth size, GH, IGF-1, and IGF-binding protein 3 (IGFBP-3). The concentrations of 22 PFASs were measured in the plasma of 224 pregnant women collected within 3 days before delivery (39.3 weeks) in Guangzhou, China, and the anthropometric data were gathered from medical records. Paired cord blood was collected at delivery to determine GH, IGF-1, and IGFBP-3 levels. Multivariable linear regression models revealed the inverse associations of several long-chain PFASs with birth weight and ponderal index as well as the significant associations of perfluorobutanoic acid and perfluorooctanoic acid (PFOA) with IGFBP-3 levels. The Bayesian kernel machine regression confirmed the association of perfluorooctane sulfonate with birth weight and ponderal index and of PFOA with IGFBP-3 and identified an inverse joint effect of exposure to a mixture of multiple PFASs on birth weight. The findings provide the first comprehensive evidence on the individual and joint effects of multiple PFASs on the neonatal birth size and hormones in the GH/IGF axis, which requires further confirmation.


Assuntos
Alcanos , Hormônio do Crescimento , Hidrocarbonetos Fluorados , Efeitos Tardios da Exposição Pré-Natal , Alcanos/efeitos adversos , Alcanos/sangue , Teorema de Bayes , China , Feminino , Sangue Fetal , Humanos , Hidrocarbonetos Fluorados/efeitos adversos , Hidrocarbonetos Fluorados/sangue , Recém-Nascido , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina , Fator de Crescimento Insulin-Like I , Gravidez
15.
Bull Environ Contam Toxicol ; 107(3): 466-474, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34379137

RESUMO

In this study, the hydrocarbons (HCs) levels in sediments from Lagoa Mirim, situated in the south of Brazil, were verified. The methodology brought together stages of pre-sonification, soxhlet extraction, and determination by gas chromatography coupled with mass spectrometry (GC/MS). Ten sample points were evaluated where ∑n-alkanes varied between 1.46 µg kg-1 ± 4.0% and 10.10 µg kg-1 ± 17.6%. Diagnostic indexes were calculated, being: Carbon Preferential Index (CPI), terrestrial/aquatic ratio (TAR), unresolved complex mixture (UCM), UCM/∑n-alkanes ratio, and n-alkane ratio with Low molecular weight hydrocarbon and High molecular weight hydrocarbons (HMW/LMW). In general, the results of this study indicate a low anthropogenic impact in the environment.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , Alcanos/análise , Brasil , Monitoramento Ambiental , Sedimentos Geológicos , Hidrocarbonetos/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes Químicos da Água/análise
16.
J Biochem Mol Toxicol ; 35(9): e22850, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34405489

RESUMO

Sodium houttuyfonate (SH) is a chemical compound synthesized by houttuynin and sodium bisulfite. As it has antinflammatory effects, SH has been widely used to treat autoimmune diseases, including post events following traumatic brain injury (TBI). Meanwhile, NOD-like receptor with pyrin domain containing-3 (NLRP3) inflammasomes in microglia may play a central role in TBI. But to date, the intracellular mechanisms involved in the anti-inflammatory effects of SH in TBI remain unknown, especially whether regulating NLRP3. To gain an insight into this possibility, we conducted cell culture and biochemical studies on the effect of SH on NLRP3 inflammasome in microglia. The results showed that SH inhibited TLR4 and NLRP3 inflammasome activation in the microglia cell. In parallel, phosphorylation of ERK and NF-κB p65, which play a key role in NLRP3 inflammasome formation, was decreased. Intraperitoneal injection of SH into TBI mice significantly reduced the modified neurological severity score (mNSS), as well as the degree of microglia apoptosis post-controlled cortical impact (CCI). Immunohistochemistry, Western blot analysis, and reverse-transcription polymerase chain reaction (RT-PCR) revealed that SH markedly reduced NLRP3 inflammasome activation, TLR4 activity, phosphorylation of ERK and NF-κB. Moreover, SH significantly inhibited microglia activation post-CCI, but effectively promoted the astrocyte activation and angiopoiesis. Taken together, our research provides evidence that SH attenuated neurological deficits post TBI through inhibiting NLRP3 inflammasome activation, via influencing the TLR4/NF-κB signaling pathway. These findings explain the intracellular mechanism of the anti-inflammatory activity caused by SH treatment following TBI.


Assuntos
Alcanos/farmacologia , Lesões Encefálicas Traumáticas , Inflamassomos/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Microglia , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Sulfitos/farmacologia , Animais , Apoptose/efeitos dos fármacos , Lesões Encefálicas Traumáticas/tratamento farmacológico , Lesões Encefálicas Traumáticas/metabolismo , Lesões Encefálicas Traumáticas/patologia , Masculino , Camundongos , Microglia/metabolismo , Microglia/patologia , Receptor 4 Toll-Like/metabolismo , Fator de Transcrição RelA/metabolismo
17.
Chemistry ; 27(59): 14730-14737, 2021 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-34402568

RESUMO

Mechanistic studies are performed on the alkane hydroxylation with m-CPBA (m-chloroperbenzoic acid) catalyzed by nickel(II) complexes, NiII (L). In the oxidation of cycloalkanes, NiII (TPA) acts as an efficient catalyst with a high yield and a high alcohol selectivity. In the oxidation of adamantane, the tertiary carbon is predominantly oxidized. The reaction rate shows first-order dependence on [substrate] and [NiII (L)] but is independent on [m-CPBA]; vobs =k2 [substrate][NiII (L)]. The reaction exhibited a relatively large kinetic deuterium isotope effect (KIE) of 6.7, demonstrating that the hydrogen atom abstraction is involved in the rate-limiting step of the catalytic cycle. Furthermore, NiII (L) supported by related tetradentate ligands exhibit apparently different catalytic activity, suggesting contribution of the NiII (L) in the catalytic cycle. Based on the kinetic analysis and the significant effects of O2 and CCl4 on the product distribution pattern, possible contributions of (L)NiII -O. and the aroyloxyl radical as the reactive oxidants are discussed.


Assuntos
Alcanos , Níquel , Catálise , Clorobenzoatos , Hidroxilação , Cinética , Ligantes , Oxirredução
18.
J Phys Chem B ; 125(33): 9610-9620, 2021 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-34402618

RESUMO

Salt ion valency and concentration vary in actual oil reservoirs, which play an important role in the functionalities of surfactant formula during chemical flooding processes to enhance oil recovery. Herein, we report a molecular dynamics (MD) study to investigate the ion valency and concentration effect on the structural and thermodynamic properties of brine-decane interfaces with anionic surfactant (SDS), under typical reservoir conditions (353 K and 200 bar). We use two different cations (Na+ and Ca2+) and a wide range of ion concentrations (up to 3.96 M) to simulate reservoir conditions. We find that ion valency has a significant effect on the molecular configurations, which further influences the thermodynamic properties. Ca2+ ions can have a strong adsorption at the interface due to the strong electrostatic interactions between Ca2+ ions and SDS, which also results in the Cl- ion enrichment at the interface. Furthermore, Ca2+ ions can form pentagon-like SDS-Ca2+ complexes through SDS-Ca2+-SDS cation bridging, which renders a nonuniform distribution of SDS at the interface. On the other hand, the cation bridging density monotonically increases as ion concentration increases for the systems without Ca2+ ions, while first increases, then decreases for the systems with Ca2+ ions. This is because the accumulation of Cl- ions at the interface at high salt concentrations can melt SDS-Ca2+ complexes. This work should provide new insights into the structural and thermodynamic properties of brine-oil interfaces with an anionic surfactant, which can facilitate the optimization of chemical flooding processes.


Assuntos
Tensoativos , Alcanos , Cátions , Sais , Termodinâmica
19.
Nat Commun ; 12(1): 5032, 2021 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-34413314

RESUMO

Methane, along with other short-chain alkanes from some Archean metasedimentary rocks, has unique isotopic signatures that possibly reflect the generation of atmospheric greenhouse gas on early Earth. We find that alkane gases from the Kidd Creek mines in the Canadian Shield are microbial products in a Neoarchean ecosystem. The widely varied hydrogen and relatively uniform carbon isotopic compositions in the alkanes infer that the alkanes result from the biodegradation of sediment organic matter with serpentinization-derived hydrogen gas. This proposed process is supported by published geochemical data on the Kidd Creek gas, including the distribution of alkane abundances, stable isotope variations in alkanes, and CH2D2 signatures in methane. The recognition of Archean microbial methane in this work reveals a biochemical process of greenhouse gas generation before the Great Oxidation Event and improves the understanding of the carbon and hydrogen geochemical cycles.


Assuntos
Bactérias/metabolismo , Planeta Terra , Gases/química , Sedimentos Geológicos/química , Hidrogênio/química , Hidrogênio/metabolismo , Metano/metabolismo , Fenômenos Microbiológicos , Alcanos/química , Alcanos/metabolismo , Biodegradação Ambiental , Canadá , Isótopos de Carbono/química , Ecossistema , Metano/química , Oxirredução
20.
Environ Sci Technol ; 55(17): 11693-11702, 2021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34431673

RESUMO

This study provides guidance on using polyurethane foam-based passive air samplers (PUF-PASs) for atmospheric nonane chlorinated paraffins (C9-CPs) and short-chain CPs (SCCPs) and reports SCCP concentrations in air in the Greater Toronto Area (GTA), Canada. We estimated the partition coefficients between PUF and air (KPUF-A) and between octanol and air (KOA) for C9-CP and SCCP congeners using the COSMO-RS method, so that PUF disk uptake profiles for each formula group could be calculated. We then measured SCCP concentrations in PUF disk samples collected from distinct source sectors in urban air across the GTA. Concentrations in samplers were used to calculate C9-CP and SCCP concentrations in air and the PUF disk uptake profiles revealed that time-weighted linear phase sampling was possible for congeners having log KOA values greater than 8.5. The highest SCCP concentrations, with an annual average concentration of 35.3 ng/m3, were measured at the industrial site, whereas lower but comparable SCCP concentrations were found in residential and background sites, with annual averages of 7.73 and 10.5 ng/m3, respectively. No consistent seasonal variation in SCCP concentrations was found in the six distinct source sectors. Direct measurements of KPUF-A and KOA values as a function of temperature could be used to increase accuracy in future studies.


Assuntos
Poluentes Atmosféricos , Hidrocarbonetos Clorados , Poluentes Atmosféricos/análise , Alcanos , China , Monitoramento Ambiental , Hidrocarbonetos Clorados/análise , Parafina/análise , Poliuretanos/análise
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