Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 317
Filtrar
1.
Environ Res ; 238(Pt 1): 117126, 2023 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-37716383

RESUMO

Given the rise in both usage and disposal of dangerous electronics, there is a catastrophic rise in assemblage of electronic waste (e-waste). E-waste including various plastic resins are among the most frequently discarded materials in electronic gadgets. In current digital era, managing e-waste has become universal concern. From the viewpoint of persisting lacuna of e-waste managing methods, the current study is designed to fabricate an eco-friendly e-waste treatment with native soil bacteria employing an enrichment culture method. In the presence of e-waste, indigenous soil microbes were stimulated to degrade e-waste. Microbial cultures were isolated using enrichment medium containing acrylonitrile-butadiene styrene (ABS) as the primary carbon source. Priestia aryabhattai MGP1 was found to be the most dominant e-polymer degrading bacterial isolate, as it was reported to degrade ABS plastic in disposed-off television casings. Furthermore, to increase degradation potential of MGP1, Response Surface Methodology (RSM) was adopted which resulted in optimized conditions (pH 7, shaking-speed 120 rpm, and temperature 30 °C), for maximum degradation (18.88%) after 2 months. The structural changes induced by microbial treatment were demonstrated by comparing the findings of Field emission scanning electron microscopy (FESEM) images and Fourier Transform Infrared (FTIR) spectra confirming the disappearance of ≡ C─H peaks along with C-H, C=C and C ≡N bond destabilization following degradation. Energy-dispersive X-ray (EDX) analyzers of the native and decomposed e-polymer samples revealed a considerable loss in elemental weight % of oxygen by 8.4% and silica by 0.5%. Magnesium, aluminium and chlorine which were previously present in the untreated sample, were also removed after treatment by the bacterial action. When seeds of Vigna radiata were screened using treated soil in the presence of both e-waste and the chosen potent bacterial strain, it was also discovered that there was reduced toxicity in terms of improved germination and growth metrics as a phytotoxicity criterion.


Assuntos
Acrilonitrila , Resíduo Eletrônico , Estireno , Plásticos , Acrilonitrila/química , Butadienos/química , Biodegradação Ambiental , Solo , Resíduo Eletrônico/análise , Polímeros , Bactérias
2.
Ecotoxicol Environ Saf ; 252: 114570, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36706528

RESUMO

With styrene and acrylonitrile in ABS plastic toys as examples, this paper introduces to the development of a systematic strategy for studying the chemical migration risk in toys. The approach, included the detection method, establishment of migration model, model verification, and the practical application of the model in risk assessment. First, simple and sensitive methods for detecting analyte residues and migration were developed by headspace GC-MS. Then, the migration models were established based on the migration data from 5 min to 168 h and verified using 11 ABS samples. The results showed that the predicted values of the models and the experimental values had a good fit (RMSE=0.10-8.72 %). Subsequently, the migration of analytes in 94 ABS toys was predicted with these models at specific migration times. The daily average exposure level to styrene and acrylonitrile were estimated for children (3 months to 3 years). At last, the migration models reasonably predicted that the cancer risk of styrene and acrylonitrile in ABS toys were 1.6 × 10-8-1.4 × 10-6 and 3.1 × 10-8-1.6 × 10-6, respectively. This research contributes to promote toy safety and child health by enriching migration models and risk assessments.


Assuntos
Acrilonitrila , Estireno , Criança , Humanos , Estireno/química , Acrilonitrila/química , Plásticos/química , Butadienos , Medição de Risco
3.
Environ Technol ; 44(22): 3331-3341, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35316146

RESUMO

Acrylonitrile wastewater was an organic wastewater with strong toxicity and poor biodegradability. Therefore, electro-catalytic technology became a promising acrylonitrile wastewater treatment technology because of no secondary pollution, wide application range and low water quality requirements. The optimal Mn-Sn modified Ru-Ir electrode material was synthesized by thermal method and applied in electro-catalytic treatment of acrylonitrile wastewater. The electrode materials were characterized by SEM, TEM, XRD, XPS and electrochemical characterization. SEM, TEM, XRD and XPS indicated that Mn and Sn were capable of incorporating and replacing the part of Ru or Ir and could alter the microstructure of Ru-Ir and the types of Mn and Sn oxides, raising the oxygen evolution potential (OEP) and voltampere charge. When the molar ratio of Mn-Sn was 1:1, OEP, voltampere charge and exchange current density could reach 1.303 V, 1.51 C/cm2 and 6.29×10-4 A/cm2, respectively. The co-doping of Mn-Sn had significant influence on the electrocatalytic performance of Ru-Ir electrode materials. The optimum synthesis conditions of Mn-Sn modified Ru-Ir electrode were as follows: the molar ratio of Mn-Sn was 1:1, calcination time was 4.0 hours, calcination temperature was 450℃, and solvent was water. Under certain conditions, the removal rate of acrylonitrile with Mn-Sn modified Ru-Ir electrode was 100%. Mn-Sn modified Ru-Ir electrode had high oxygen evolution potential and good removal effect of acrylonitrile, which was higher than that of ruthenium iridium electrode and RuO2 electrode.


Assuntos
Acrilonitrila , Acrilonitrila/química , Águas Residuárias , Cloretos , Eletrodos , Oxigênio
4.
Waste Manag ; 149: 1-10, 2022 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-35689973

RESUMO

The mismanagement of waste electrical and electronic equipment (WEEE) resulted in numerous discarded plastics in the natural environment, and these waste plastics might experience aging, breaking, and migration, which becomes a crucial microplastic source. Sustainable management of WEEE plastics presents a considerable opportunity for resource recovery and microplastic pollution prevention. Flotation separation is a significant process of mechanical recycling, while most flotation methods can only deal with binary plastic mixtures. In this work, an advanced, stepwise, and sustainable flotation method was advocated to separate multi-plastics by polymeric aluminum chloride (PAC) modification. The abundant hydrophilic groups and environmental friendliness of PAC prompted us to further investigate the wetting effect. PAC had varied hydrophilization effects on acrylonitrile butadiene styrene (ABS) and polystyrene (PS) surfaces, but polyethylene terephthalate (PET) retained hydrophobicity. Treatment conditions, including PAC dosage, temperature, time, and pH were optimized. 100% of PET could be purified after primary separation, and the purities of ABS and PS could reach 100% and 97.4% after secondary separation, respectively. The strength of the interaction was determined by the different surface potentials and functional groups. In PAC solution, long-chain molecules or ions might interact with plastic surfaces electrostatically, and Al3+ could bridge long-chain molecules and plastic surfaces, thereby strengthening the polymer hydrophilicity. We further improved the PAC treatment process, and the reuse of PAC reduced modifier usage to 84.4 g/ton waste plastics, which was cost-effective in industrial applications. A preliminary evaluation of the energy consumption and environmental impact indicated that PAC treatment was superior to other modification methods. This work is an initial attempt at the stepwise separation of waste plastic and shows promising prospects for recycling plastic waste.


Assuntos
Acrilonitrila , Eliminação de Resíduos , Acrilonitrila/química , Cloreto de Alumínio , Eletrônica , Microplásticos , Plásticos/química , Polietilenotereftalatos , Polímeros/química , Poliestirenos/química , Reciclagem , Eliminação de Resíduos/métodos
5.
Molecules ; 27(7)2022 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-35408448

RESUMO

Five focused compound libraries (forty-nine compounds), based on prior studies in our laboratory were synthesized and screened for antibiotic and anti-fungal activity against S. aureus, E. coli, K. pneumoniae, P. aeruginosa, A. baumannii, C. albicans and C. neoformans. Low levels of activity, at the initial screening concentration of 32 µg/mL, were noted with analogues of (Z)-2-(3,4-dichlorophenyl)-3-phenylacrylonitriles which made up the first two focused libraries produced. The most promising analogues possessing additional substituents on the terminal aromatic ring of the synthesised acrylonitriles. Modifications of the terminal aromatic moiety were explored through epoxide installation flowed by flow chemistry mediated ring opening aminolysis with discreet sets of amines to the corresponding amino alcohols. Three new focused libraries were developed from substituted anilines, cyclic amines, and phenyl linked heterocyclic amines. The aniline-based compounds were inactive against the bacterial and fungal lines screened. The introduction of a cyclic, such as piperidine, piperazine, or morpholine, showed >50% inhibition when evaluated at 32 µg/mL compound concentration against methicillin-resistant Staphylococcus aureus. Examination of the terminal aromatic substituent via oxirane aminolysis allowed for the synthesis of three new focused libraries of afforded amino alcohols. Aromatic substituted piperidine or piperazine switched library activity from antibacterial to anti-fungal activity with ((Z)-2-(3,4-dichlorophenyl)-3-(4-(2-hydroxy-3-(4-methylpiperazin-1-yl)propoxy)phenyl)acrylonitrile), ((Z)-2-(3,4-dichlorophenyl)-3-(4-(2-hydroxy-3-(4-(4-hydroxyphenyl)piperazin-1-yl)propoxy)-phenyl)acrylonitrile) and ((Z)-3-(4-(3-(4-cyclohexylpiperazin-1-yl)-2-hydroxypropoxy)-phenyl)-2-(3,4-dichlorophenyl)-acrylonitrile) showing >95% inhibition of Cryptococcus neoformans var. grubii H99 growth at 32 µg/mL. While (Z)-3-(4-(3-(cyclohexylamino)-2-hydroxypropoxy)phenyl)-2-(3,4-dichlorophenyl)-acrylonitrile, (S,Z)-2-(3,4-dichlorophenyl)-3-(4-(2-hydroxy-3-(piperidin-1-yl)propoxy)phenyl)acrylonitrile, (R,Z)-2-(3,4-dichlorophenyl)-3-(4-(2-hydroxy-3-(piperidin-1-yl)propoxy)phenyl)acrylonitrile, (Z)-2-(3,4-dichlorophenyl)-3-(4-(2-hydroxy-3-(D-11-piperidin-1-yl)propoxy)phenyl)-acrylonitrile, and (Z)-3-(4-(3-(4-cyclohexylpiperazin-1-yl)-2-hydroxypropoxy)-phenyl)-2-(3,4-dichlorophenyl)-acrylonitrile 32 µg/mL against Staphylococcus aureus.


Assuntos
Acrilonitrila , Staphylococcus aureus Resistente à Meticilina , Acrilonitrila/química , Amino Álcoois , Antibacterianos/química , Antifúngicos/química , Escherichia coli , Klebsiella pneumoniae , Testes de Sensibilidade Microbiana , Piperazina , Pseudomonas aeruginosa , Staphylococcus aureus , Relação Estrutura-Atividade
6.
Artigo em Inglês | MEDLINE | ID: mdl-34780321

RESUMO

Styrene-acrylonitrile-copolymer (SAN) and acrylonitrile-butadiene-styrene-copolymer (ABS) are gaining in importance as food contact materials. Oligomers and other non-intentionally added substances can migrate into foodstuffs. Five SAN and four ABS samples from the German market and manufacturers were extracted and the extractable oligomers were characterised by high performance liquid chromatography-mass spectrometry/ultraviolet detection/chemiluminescence nitrogen detection/fluorescence detection and gas chromatography-mass spectrometry. Trimers, formed from acrylonitrile and styrene units, were determined to be the dominating group of extractable oligomers in SAN and ABS in concentrations of about 4900-15800 mg/kg material. Furthermore, styrene-acrylonitrile dimers, styrene oligomers, styrene monomer and ethylbenzene were identified in the sample extracts. Migration testing with three consecutive migrations for multiple use articles was performed for two SAN articles. Migration of trimers into water, 3% acetic acid, 10% and 20% ethanol under hot-fill conditions (70°C, 2 h) was not detectable above 9 µg/dm2, while 50% ethanol acting as a food simulant for milk (124 µg/dm2 trimers during the third migration) was shown to overestimate the actual migration into milk (< 11 µg/dm2 trimers at 70°C, 2 h). 2-Amino-3-methyl-1-naphthalenecarbonitrile (AMNC), an oligomer degradation product and a primary aromatic amine, was detected in all material sample extracts (0.3-17.1 mg/kg material) and was released into food simulants in low amounts (< 0.014 µg/dm2 during the third migration into 50% ethanol at 70°C, 2 h).


Assuntos
Acrilonitrila/isolamento & purificação , Butadienos/isolamento & purificação , Análise de Alimentos , Contaminação de Alimentos/análise , Polímeros/isolamento & purificação , Estireno/isolamento & purificação , Acrilonitrila/química , Butadienos/química , Polímeros/química , Estireno/química
7.
Eur J Med Chem ; 222: 113590, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34139625

RESUMO

Microtubules (MTs) are the principal target for drugs acting against mitosis. These compounds, called microtubule targeting agents (MTAs), cause a mitotic arrest during G2/M phase, subsequently inducing cell apoptosis. MTAs could be classified in two groups: microtubule stabilising agents (MSAs) and microtubule destabilising agents (MDAs). In this paper we present a new series of (E) (Z)-2-(5,6-difluoro-(1H)2H-benzo[d] [1,2,3]triazol-1(2)-yl)-3-(R)acrylonitrile (9a-j, 10e, 11a,b) and (E)-2-(1H-benzo[d] [1,2,3]triazol-1-yl)-3-(R)acrylonitrile derivatives (13d,j), which were recognised to act as MTAs agents. They were rationally designed, synthesised, characterised and subjected to different biological assessments. Computational docking was carried out in order to investigate the potential binding to the colchicine-binding site on tubulin. From this first prediction, the di-fluoro substitution seemed to be beneficial for the binding affinity with tubulin. The new fluorine derivatives, here presented, showed an improved antiproliferative activity when compared to the previously reported compounds. The biological evaluation included a preliminary antiproliferative screening on NCI60 cancer cells panel (1-10 µM). Compound 9a was selected as lead compound of the new series of derivatives. The in vitro XTT assay, flow cytometry analysis and immunostaining performed on HeLa cells treated with 9a showed a considerable antiproliferative effect, (IC50 = 3.2 µM), an increased number of cells in G2/M-phase, followed by an enhancement in cell division defects. Moreover, ß-tubulin staining confirmed 9a as a MDA triggering tubulin disassembly, whereas colchicine-9a competition assay suggested that compound 9a compete with colchicine for the binding site on tubulin. Then, the co-administration of compound 9a and an extrusion pump inhibitor (EPI) was investigated: the association resulted beneficial for the antiproliferative activity and compound 9a showed to be client of extrusion pumps. Finally, structural superimposition of different colchicine binding site inhibitors (CBIs) in clinical trial and our MDA, provided an additional confirmation of the targeting to the predicted binding site. Physicochemical, pharmacokinetic and druglikeness predictions were also conducted and all the newly synthesised derivatives showed to be drug-like molecules.


Assuntos
Acrilonitrila/farmacologia , Antineoplásicos/farmacologia , Microtúbulos/efeitos dos fármacos , Triazóis/farmacologia , Acrilonitrila/química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Células HeLa , Humanos , Mitose/efeitos dos fármacos , Simulação de Acoplamento Molecular , Estrutura Molecular , Relação Estrutura-Atividade , Triazóis/química
8.
Food Chem ; 359: 129925, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-33964657

RESUMO

A modified QuEChERS method for determining cyenopyrafen in strawberries, mandarins and their processed products was established with a good linearity (R2 > 0.9981), accuracy (recoveries of 83% to 111%) and precision (relative standard deviations of 0.9% to 14%). The limit of quantification (LOQ) was 0.01 mg/kg. Field results showed that the half-lives of cyenopyrafen were 6.8 and 11.8 d in strawberry and mandarin respectively, and that the final residues were within established maximum residue limits (MRLs). The household processing factors (PFs) for cyenopyrafen residues in strawberry and mandarin fruits were also studied: residues increased in strawberry jam (PF 1.51) and mandarin juice (1.31) but decreased in strawberries (0.58) and mandarin pulp (<0.17) after washing and peeling, respectively. A risk assessment showed that the risk from long-term dietary exposures to cyenopyrafen was 73.73%, indicating that consuming these products was unlikely to present a public health concern.


Assuntos
Acrilonitrila/análogos & derivados , Citrus sinensis/química , Fragaria/química , Frutas/química , Resíduos de Praguicidas/química , Pirazóis/química , Acrilonitrila/análise , Acrilonitrila/química , Exposição Dietética , Resíduos de Praguicidas/análise , Pirazóis/análise , Medição de Risco
9.
Int J Mol Sci ; 22(5)2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33668139

RESUMO

New 2-(thien-2-yl)-acrylonitriles with putative kinase inhibitory activity were prepared and tested for their antineoplastic efficacy in hepatoma models. Four out of the 14 derivatives were shown to inhibit hepatoma cell proliferation at (sub-)micromolar concentrations with IC50 values below that of the clinically relevant multikinase inhibitor sorafenib, which served as a reference. Colony formation assays as well as primary in vivo examinations of hepatoma tumors grown on the chorioallantoic membrane of fertilized chicken eggs (CAM assay) confirmed the excellent antineoplastic efficacy of the new derivatives. Their mode of action included an induction of apoptotic capsase-3 activity, while no contribution of unspecific cytotoxic effects was observed in LDH-release measurements. Kinase profiling of cancer relevant protein kinases identified the two 3-aryl-2-(thien-2-yl)acrylonitrile derivatives 1b and 1c as (multi-)kinase inhibitors with a preferential activity against the VEGFR-2 tyrosine kinase. Additional bioinformatic analysis of the VEGFR-2 binding modes by docking and molecular dynamics calculations supported the experimental findings and indicated that the hydroxy group of 1c might be crucial for its distinct inhibitory potency against VEGFR-2. Forthcoming studies will further unveil the underlying mode of action of the promising new derivatives as well as their suitability as an urgently needed novel approach in HCC treatment.


Assuntos
Acrilonitrila/química , Carcinoma Hepatocelular/tratamento farmacológico , Neoplasias Hepáticas/tratamento farmacológico , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Tiofenos/farmacologia , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Proliferação de Células , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Células Hep G2 , Humanos , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Simulação de Acoplamento Molecular , Estrutura Molecular , Relação Estrutura-Atividade , Tiofenos/química
10.
J Mol Recognit ; 34(4): e2880, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33166010

RESUMO

In this work, seven acrylonitrile derivatives were selected as potential inhibitors of fat and obesity-related proteins (FTO) by the aid of fluorescence spectroscopy, ultraviolet visible spectroscopy, molecular docking, and cytotoxicity methods. Results show that the interaction between 3-amino-2-(4-chlorophenyl)-3-phenylacrylonitrile (1a) and FTO was the strongest among these derivatives. Thermodynamic analysis and molecular modeling show that the main force between 1a and FTO is hydrophobic interaction. The cytotoxicity test showed that the IC50 value of 1a was 46.64 µmol/L, which indicated 1a had the smallest IC50 value and had the best inhibitory effect on the proliferation of leukemia K562 cells among the seven derivatives. Both our previous results and this work show that chlorine atoms play important role in the binding of small molecules and FTO. This work brings new information for the study of FTO inhibitors.


Assuntos
Acrilonitrila/química , Acrilonitrila/metabolismo , Dioxigenase FTO Dependente de alfa-Cetoglutarato/química , Dioxigenase FTO Dependente de alfa-Cetoglutarato/metabolismo , Cloro/química , Acrilonitrila/farmacologia , Antineoplásicos/química , Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Fluorescência , Humanos , Células K562 , Modelos Moleculares , Espectrometria de Fluorescência/métodos , Espectrofotometria Ultravioleta , Termodinâmica
11.
Eur J Med Chem ; 211: 113003, 2021 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-33248847

RESUMO

We present the design, synthesis and biological activity of novel N-substituted benzimidazole based acrylonitriles as potential tubulin polymerization inhibitors. Their synthesis was achieved using classical linear organic and microwave assisted techniques, starting from aromatic aldehydes and N-substituted-2-cyanomethylbenzimidazoles. All newly prepared compounds were tested for their antiproliferative activity in vitro on eight human cancer cell lines and one reference non-cancerous assay. N,N-dimethylamino substituted acrylonitriles 30 and 41, bearing N-isobutyl and cyano substituents placed on the benzimidazole nuclei, showed strong and selective antiproliferative activity in the submicromolar range of inhibitory concentrations (IC50 0.2-0.6 µM), while being significantly less toxic than reference systems docetaxel and staurosporine, thus promoting them as lead compounds. Mechanism of action studies demonstrated that two most active compounds inhibited tubulin polymerization. Computational analysis confirmed the suitability of the employed benzimidazole-acrylonitrile skeleton for the binding within the colchicine binding site in tubulin, thus rationalizing the observed antitumor activities, and demonstrated that E-isomers are active substances. It also provided structural determinants affecting both the binding position and the matching affinities, identifying the attached NMe2 group as the most dominant in promoting the binding, which allows ligands to optimize favourable cation∙∙∙π and hydrogen bonding interactions with Lys352.


Assuntos
Acrilonitrila/farmacologia , Antineoplásicos/farmacologia , Benzimidazóis/farmacologia , Teoria da Densidade Funcional , Tubulina (Proteína)/metabolismo , Acrilonitrila/síntese química , Acrilonitrila/química , Antineoplásicos/síntese química , Antineoplásicos/química , Benzimidazóis/síntese química , Benzimidazóis/química , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Estrutura Molecular , Polimerização/efeitos dos fármacos , Relação Estrutura-Atividade , Células Tumorais Cultivadas
12.
Bioorg Med Chem ; 28(21): 115605, 2020 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-33065441

RESUMO

One of the most prevailing metabolic disorder diabetes mellitus has become the global health issue that has to be addressed and cured. Different marketed drugs have been made available for the treatment of diabetes but there is still a need of introducing new therapeutic agents that are economical and have lesser or no side effects. The current study deals with the synthesis of indole acrylonitriles (3-23) and the evaluation of these compounds for their potential for α-glucosidase inhibition. The structures of these synthetic molecules were deduced by using different spectroscopic techniques. Acarbose (IC50 = 2.91 ± 0.02 µM) was used as standard in this study and the synthetic molecules (3-23) have shown promising α-glucosidase inhibitory activity. Compounds 4, 8, 10, 11, 14, 18, and 21 displayed superior inhibition of α-glucosidase enzyme in the range of (IC50 = 0.53 ± 0.01-1.36 ± 0.04 µM) as compared to the standard acarbose. Compound 10 (IC50 = 0.53 ± 0.01 µM) was the most effective inhibitor of this library and displayed many folds enhanced activity in contrast to the standard. Molecular docking of synthetic compounds was performed to verify the binding interactions of ligand with the active site of enzyme. This study had identified a number of potential α-glucosidase inhibitors that can be used for further research to identify a potent therapeutic agent against diabetes.


Assuntos
Inibidores de Glicosídeo Hidrolases/química , Hipoglicemiantes/síntese química , Indóis/química , alfa-Glucosidases/metabolismo , Acrilonitrila/química , Sítios de Ligação , Domínio Catalítico , Diabetes Mellitus/tratamento farmacológico , Inibidores de Glicosídeo Hidrolases/metabolismo , Inibidores de Glicosídeo Hidrolases/uso terapêutico , Humanos , Hipoglicemiantes/metabolismo , Hipoglicemiantes/uso terapêutico , Indóis/metabolismo , Indóis/uso terapêutico , Simulação de Acoplamento Molecular , Solubilidade , Relação Estrutura-Atividade , alfa-Glucosidases/química
13.
J Vis Exp ; (164)2020 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-33104072

RESUMO

Three-dimensional (3D) printing as a type of additive manufacturing shows continuing increase in application and consumer popularity. The fused filament fabrication (FFF) is an inexpensive method used most frequently by consumers. Studies with 3D printers have shown that during the printing process particulate and volatile substances are released. Handheld 3D printing pens also use the FFF method but the consumer's proximity to the 3D pens gives reason to higher exposure compared to a 3D printer. At the same time, 3D printing pens are often marketed for children who could be more sensitive to the printing emission. The aim of this study was to implement a low cost method to analyze the emissions of 3D printing pens. Polylactide (PLA) and acrylonitrile butadiene styrene (ABS) filaments of different colors were tested. In addition, filaments containing metal and carbon nanotubes (CNTs) were analyzed. An 18.5 L chamber and sampling close to the emission source was used to characterize emissions and concentrations near the breathing zone of the user. Particle emissions and particle size distributions were measured and the potential release of metal particles and CNTs investigated. Particle number concentrations were found in a range of 105 - 106 particles/cm3, which is comparable to previous reports from 3D printers. Transmission electron microscopy (TEM) analysis showed nanoparticles of the different thermoplastic materials as well as of metal particles and CNTs. High contents of metal were observed by inductively coupled plasma mass spectrometry (ICP-MS). These results call for a cautious use of 3D pens due to potential risk to the consumers.


Assuntos
Material Particulado/análise , Impressão Tridimensional/instrumentação , Acrilonitrila/química , Aerossóis/análise , Butadienos/química , Metais/análise , Nanotubos de Carbono , Tamanho da Partícula , Poliésteres/química , Espectrofotometria Atômica , Estireno/química
14.
J Biol Inorg Chem ; 25(6): 903-911, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32812122

RESUMO

An Fe-type nitrile hydratase α(ɛ) protein complex from Rhodococcus equi TG328-2 (ReNHase) was discovered and shown by MALDI-TOF to form a 1:1 complex. As isolated, the α(ɛ) protein complex exhibited no detectable NHase activity even in the presence of iron. The addition of the ReNHase ß-subunit and Fe(II) to the ReNHase apo-α(ε) complex, provided an enzyme with a kcat value of 0.7 ± 0.1 s-1 using acrylonitrile as the substrate, indicating that the ß-subunit is important for the reconstitution of NHase activity. The addition of the reducing agent TCEP enhanced the activity by more than 50% (kcat of 1.7 ± 0.2 s-1). As the (ɛ) protein was previously shown to bind and hydrolyze GTP, the addition of GTP to the as-purified α(ε) complex provided a kcat value of 1.1 ± 0.2 s-1, in the presence of Fe(II) and ß-subunit. The addition of TCEP to this combination further enhanced the activity (kcat of 2.1 ± 0.3 s-1). Apo α-subunit was expressed in purified and added to the (ɛ) protein and ß-subunits plus Fe(II) and TCEP resulting in a kcat value of 0.7 ± 0.2 s-1 suggesting an α(ɛ) complex can form in vitro. The addition of GTP to this sample increased the observed rate of nitrile hydration by ~ 30%, while TCEP free samples exhibited no activity. Taken together, these data provide insight into the role of the (ɛ) protein and the newly discovered α(ɛ) complex in NHase metallocenter assembly.


Assuntos
Proteínas de Bactérias/química , Hidroliases/química , Ferro/química , Rhodococcus equi/enzimologia , Acrilonitrila/química , Catálise , Ativação Enzimática , Hidrólise , Cinética , Ligação Proteica , Conformação Proteica , Rhodococcus equi/genética
15.
Int J Biol Macromol ; 164: 2312-2322, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32810531

RESUMO

In this work, lignin was grafted with acrylonitrile to control the molecular weights and molecular architecture of polyacrylonitrile (PAN)/lignin copolymer. Lignin-acrylonitrile monomer (LA-AN) and its copolymers with AN were synthesized successfully. First, lignin was aminated (LA) and then grafted with 2-chloroacrylonitrile to prepare LA-AN. The copolymerization of LA-AN and AN was carried out using 2,2-azobis(2-methylpropionitrile) as initiator. The modification, grafting, and copolymerization were confirmed with Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and X-ray photoelectron spectroscopy. Contrary to the previous studies, gel permeation chromatography showed that the molecular weight of the copolymers was increased significantly due to the presence of lignin (up to 203,944). Viscosity analysis revealed that the addition of lignin reduces the viscosity of the copolymer solution. While thermogravimetric analysis showed improvement in the degradation temperature, and lowering of the melt temperature, as revealed by differential scanning calorimetry. These findings indicated that the attaching acrylonitrile on lignin molecules result in control of the molecular weight and molecular structure of PAN/Lignin copolymers which results in enhanced solubility, spinnability, and other properties associated with molecular weight.


Assuntos
Resinas Acrílicas/química , Lignina/química , Polímeros/química , Acrilonitrila/análogos & derivados , Acrilonitrila/química , Varredura Diferencial de Calorimetria/métodos , Peso Molecular , Fenômenos Físicos , Polimerização , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Temperatura , Viscosidade
16.
Int J Biol Macromol ; 164: 2038-2050, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32739512

RESUMO

In this study, the effect of cellulose nanocrystals (CNCs) incorporation on the structure-properties of acrylonitrile-butadiene rubber (NBR films), with particular focus on curing enhancement and reinforcing potential, was investigated. The NBR crosslinking efficiency, observed from nuclear magnetic resonance analysis, increased with successive CNC concentration increases due to better dispersion of ZnO from Zn-cellulose complex formation. Energy dispersive X-ray and transmission electron microscope analysis of the films revealed increasingly well-dispersed ZnO with increasing CNC. The increase in the crosslinking density in conjuncture with the reinforcing capability of CNCs resulted in increases in the tensile strength, stiffness, toughness, tear strength and elongation by 203, 8300, 664, 179, and 14%, respectively for films containing 3 phr CNC compared to the neat NBR. The incorporation of 0.5 phr CNC reduced the water absorption of neat CNC by 250%. Overall, water absorption of the nanocomposite films was considerably lower than that of the neat NBR through CNC consolidation of the rubber particles by reducing free volume in the NBR structure. The nanocomposite films show promise for glove and other dipped product applications where improved tear resistance and overall physical properties improvement are needed without compromising the integrity.


Assuntos
Acrilonitrila/química , Butadienos/química , Celulose/química , Nanopartículas/química , Borracha/química , Água/química , Nanocompostos/química , Resistência à Tração , Óxido de Zinco/química
17.
Carbohydr Polym ; 245: 116505, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32718616

RESUMO

In this work, chitin nanowhiskers with high crystallinity index were obtained from shrimp shells waste using acid hydrolysis method and then comprehensively characterized. Subsequently, the impact of chitin nanowhisker content on processing and performance of acrylonitrile-butadiene rubber based nanocomposites was evaluated. The results showed that the addition of chitin nanowhiskers increased tensile strength and tear strength of nanocomposites by 116 % and 54 %, which was related to suitable dispersion of chitin nanowhiskers in matrix. Reinforcing effect of chitin nanowhiskers in acrylonitrile-butadiene rubber was also confirmed by Wolff activity coefficient, glass transition temperature and equilibrium swelling measurements. Moreover, it was found that higher content chitin nanowhiskers significantly improve the thermal stability of studied nanocomposites. The incorporation of chitin nanowhiskers resulted in increase of 74 °C for onset degradation temperature. This work confirmed that shrimp shell waste can be upcycled into chitin nanowhiskers - promising green filler in NBR for high-performance elastomeric applications.


Assuntos
Acrilonitrila/química , Exoesqueleto/química , Butadienos/química , Quitina/química , Nanocompostos/química , Penaeidae/química , Borracha/química , Animais , Elasticidade , Hidrólise , Resistência à Tração , Temperatura de Transição
18.
Steroids ; 160: 108659, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32439407

RESUMO

Four novel deoxycholic acid tethered α-cyanostilbenes were designed, synthesized and characterized using detailed spectroscopic analysis. The synthesized deoxycholic acid tethered α-cyanostilbene derivatives formed stable gels with a variety of solvents, such as xylene, toluene, mesitylene, decane, dodecane etc. The stable gels showed lamellar sheet type structures stacked over each other, consisting of entangled fibres as evident from SEM, TEM and Fluorescence Microscopy images; The synthesized compounds exhibited AIEE behaviour in H2O/THF mixture, with the maximum emission observed in 70% H2O/THF fraction along with a bathochromic shift. A solvent thickening experiment was perform to establish the mechanism of AIEE and the AIEE property was explored for bacterial bio-imaging. The synthesized derivatized steroids proved their potential as multifunctional organic materials.


Assuntos
Acrilonitrila/análogos & derivados , Ácido Desoxicólico/química , Corantes Fluorescentes/química , Imagem Molecular , Serratia marcescens/isolamento & purificação , Staphylococcus aureus/isolamento & purificação , Acrilonitrila/química , Corantes Fluorescentes/síntese química , Géis/síntese química , Géis/química , Microscopia de Fluorescência , Conformação Molecular , Peso Molecular
19.
Molecules ; 25(6)2020 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-32204541

RESUMO

Heterojunction nanofibers of PAN decorated with sulfate doped Ag3PO4 nanoparticles (SO42--Ag3PO4/PAN electrospun nanofibers) were successfully fabricated by combining simple and versatile electrospinning technique with ion exchange reaction. The novel material possessing good flexibility could exhibit superior antibacterial property over sulfate undoped species (Ag3PO4/PAN electrospun nanofibers). FESEM, XRD, FTIR, XPS and DRS were applied to characterize the morphology, phase structure, bonding configuration, elemental composition, and optical properties of the as fabricated samples. FESEM characterization confirmed the successful incorporation of SO42--Ag3PO4 nanoparticles on PAN electrospun nanofibers. The doping of SO42- ions into Ag3PO4 crystal lattice by replacing PO43- ions can provide sufficient electron-hole separation capability to the SO42--Ag3PO4/PAN heterojunction to generate reactive oxygen species (ROS) under visible light irradiation and enhances its antibacterial performance. Finally, we hope this work may offer a new paradigm to design and fabricate other types of flexible self-supporting negative-ions-doped heterojunction nanofibers using electrospinning technique for bactericidal applications.


Assuntos
Resinas Acrílicas/química , Acrilonitrila/análogos & derivados , Antibacterianos/síntese química , Prata/farmacologia , Sulfatos/química , Acrilonitrila/química , Antibacterianos/química , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Nanopartículas Metálicas , Testes de Sensibilidade Microbiana , Nanocompostos/química , Tamanho da Partícula , Prata/química , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento
20.
ChemMedChem ; 15(6): 490-505, 2020 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-32012442

RESUMO

Lead (Z)-N-(4-(2-cyano-2-(3,4-dichlorophenyl)vinyl)phenyl)acetamide, 1 showed MCF-7 GI50 =30 nM and 400-fold selective c.f. MCF10A (normal breast tissue). Acetamide moiety modification (13 a-g) to introduce additional hydrophobicity was favoured with MCF-7 breast cancer cell activity enhanced at 1.3 nM. Other analogues were potent against the HT29 colon cancer cell line at 23 nM. Textbook SAR data was observed in the MCF-7 cell line, in an MTT assay, via the ortho (17 a), meta (17 b) and para (13 f). The amino alcohol -OH moiety was pivotal, but no stereochemical preference noted. But, these data did not fit our homology modelling expectations. Aberrant MTT ((3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) screening results and metabolic interference confirmed by sulforhodamine B (SRB) screening. Interfering analogues resulted in 120 and 80-fold CYP1A1 and CYP1A2 amplification, with no upregulation of SULT1A1. This is consistent with activation of the AhR pathway. Piperidine per-deuteration reduced metabolic inactivation. 3-OH / 4-OH piperidine analogues showed differential MTT and SRB activity supporting MTT assay metabolic inactivation. Data supports piperidine 3-OH, but not the 4-OH, as a CYP substrate. This family of ß-amino alcohol substituted 3,4-dichlorophenylacetonitriles show broad activity modulated via the AhR pathway. By SRB analysis the most potent analogue was 23 b, (Z)-3-(4-(3-(4-phenylpiperidin-1-yl)-2-hydroxypropoxy)phenyl)-2-(3,4-dichlorophenyl)-acrylonitrile.


Assuntos
Acrilonitrila/farmacologia , Amino Álcoois/farmacologia , Antineoplásicos/farmacologia , Fatores de Transcrição Hélice-Alça-Hélice Básicos/agonistas , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Receptores de Hidrocarboneto Arílico/agonistas , Receptores de Hidrocarboneto Arílico/metabolismo , Acrilonitrila/análogos & derivados , Acrilonitrila/química , Amino Álcoois/química , Antineoplásicos/química , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Estrutura Molecular , Fenótipo , Relação Estrutura-Atividade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...