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1.
J Agric Food Chem ; 68(8): 2297-2305, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-31995372

RESUMO

We previously discovered a method to estimate the groundwater mean residence time using the changes in the enantiomeric ratio of metolachlor ethanesulfonic acid (MESA), (2-[(2-ethyl-6-methylphenyl)(2-methoxy-1-methylethyl)amino]-2-oxoethanesulfonic acid), a metabolite of the herbicide metolachlor. However, many grab samples would be needed for each watershed over an extended period, and this is not practical. Thus, we examined the use of a polar organic chemical integrative sampler (POCIS) deployed for 28 days combined with a modified liquid chromatography-mass spectrometry LC-MS/MS method to provide a time-weighted average of the MESA enantiomeric ratio. POCISs equipped with hydrophilic-lipophilic-balanced (HLB) discs were deployed at five sites across the United States where metolachlor was used before and after 1999 and compared the effectiveness of the POCIS to capture MESA versus grab samples. In addition, an in situ POCIS sampling rate (Rs) for MESA was calculated (0.15 L/day), the precision of MESA extraction from stored POCIS discs was determined, and the effectiveness of HLB to extract MESA was examined. Finally, using molecular modeling, the influence of the asymmetric carbon of metolachlor degradation on the MESA enantiomeric ratio was predicted to be negligible. Results of this work will be used in projects to discern the groundwater mean residence times, to evaluate the delivery of nitrate-N from groundwater to surface waters under various soil, agronomic, and land use conditions, and to examine the effectiveness of conservation practices.


Assuntos
Acetamidas/química , Alcanossulfonatos/química , Monitoramento Ambiental/métodos , Água Subterrânea/química , Herbicidas/química , Compostos Orgânicos/química , Poluentes Químicos da Água/química , Cromatografia Líquida de Alta Pressão/métodos , Estereoisomerismo , Espectrometria de Massas em Tandem/métodos
2.
Eur J Med Chem ; 186: 111861, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31734025

RESUMO

Respiratory syncytial virus (RSV) and influenza A virus (IAV) are two of the most common viruses that cause substantial morbidity and mortality in infants, young children, elderly persons, and immunocompromised individuals worldwide. Currently, there are no licensed vaccines or selective antiviral drugs against RSV infections and most IAV strains become resistant to clinical anti-influenza drug. Here, we described the discovery of a series of 2-((1H-indol-3-yl)thio)-N-phenyl-acetamide as novel and potent RSV and IAV dual inhibitors. Thirty-five derivatives were designed, prepared, and evaluated for their anti-RSV and anti-IAV activities. Among the tested compounds, 14'c, 14'e, 14'f, 14'h, and 14'i exhibited excellent activity against both RSV and IAV, which showed low micromolar to sub-micromolar EC50 values. Further, compounds 14'c and 14'e were identified as the most promising dual inhibitors with lesser cytotoxicity than the clinical drug, ribavirin. These findings may contribute to the development of a lead compound for the treatment of RSV and/or IAV infections.


Assuntos
Acetamidas/farmacologia , Antivirais/farmacologia , Desenho de Drogas , Influenzavirus A/efeitos dos fármacos , Vírus Sincicial Respiratório Humano/efeitos dos fármacos , Acetamidas/síntese química , Acetamidas/química , Antivirais/síntese química , Antivirais/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Células HEK293 , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Relação Estrutura-Atividade , Replicação Viral/efeitos dos fármacos
3.
Eur J Med Chem ; 186: 111867, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31757525

RESUMO

Using the principle of bioisosteric replacement, we present a structure-based design approach to obtain new Axl kinase inhibitors with significant activity at the kinase and cellular levels. Through a stepwise structure-activity relationships exploration, a series of 6,7-disubstituted quinoline derivatives, which contain 1,3,4-oxadiazol acetamide moiety as novel Linker, were ultimately synthesized with Axl as the primary target. Most of them exhibited moderate to excellent activity, with IC50 values ranging from 0.032 to 1.54 µM against the tested cell lines. Among them, the most promising compound 47e, as an Axl kinase inhibitor (IC50 = 10 nM), shows remarkable cytotoxicity against A549, HT-29, PC-3, MCF-7, H1975 and MDA-MB-231 cell lines. More importantly, 47e also shows a significant inhibitory effect on EGFR-TKI resistant NSCLC cell lines H1975/gefitinib. Meanwhile, this study provides a novel type of linker for Axl kinase inhibitors, namely 1,3,4-oxadiazol acetamide moiety, which is out of the scope of the "5- atoms role ".


Assuntos
Acetamidas/farmacologia , Antineoplásicos/farmacologia , Desenho de Drogas , Oxidiazóis/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Acetamidas/síntese química , Acetamidas/química , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Estrutura Molecular , Oxidiazóis/síntese química , Oxidiazóis/química , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Proteínas Proto-Oncogênicas/metabolismo , Receptores Proteína Tirosina Quinases/metabolismo , Relação Estrutura-Atividade
4.
Chemosphere ; 240: 124761, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31546190

RESUMO

The formation and control of haloacetamides (HAcAms) in drinking water have raised high attention due to their high genotoxicity and cytotoxicity, especially the most cytotoxic one, diiodoacetamide (DIAcAm). In this study, the degradation of DIAcAm by UV/chlorination was investigated in terms of degradation kinetics, efficiency, influencing factors, oxidation products and toxicity evaluation. Results revealed that the degradation of DIAcAm by UV/chlorine process followed pseudo-first-order kinetics, and the rate constant between DIAcAm and OH radicals was determined as 2.8 × 109 M-1 s-1. The contribution of Cl to DIAcAm degradation by UV/chlorine oxidation was negligible. Increasing chlorine dosage and decreasing pH significantly promoted the DIAcAm degradation during UV/chlorine oxidation, but the presence of bicarbonate (HCO3-) and natural organic matter (NOM) inhibited it. The mass balance analysis of iodine species was also evaluated during UV/chlorine oxidation of DIAcAm. In this process, with DIAcAm decreasing from 16.0 to 0.8 µM-I in 20 min, IO3-, I- and HOI/I2 increased from 0 to 6.3, 6.1 and 0.5 µM-I, respectively. The increase of CHO cell viability during DIAcAm degradation indicated that the toxicity of DIAcAm could be decreased by chlorination, UV irradiation and UV/chlorine oxidation treatments, in which UV/chlorine oxidation was more effective on toxicity reduction than chlorination and UV irradiation alone.


Assuntos
Acetamidas/química , Poluentes Químicos da Água/química , Cloro/análise , Halogenação , Cinética , Oxirredução , Raios Ultravioleta , Água , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade , Purificação da Água/métodos
5.
Biosci Biotechnol Biochem ; 84(1): 25-30, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31516064

RESUMO

The Japanese orange fly, Bactrocera tsuneonis, infests various citrus crops. While male pheromone components accumulated in the rectal glands are well characterized for Bactrocera, but information regarding the chemical factors involved in the life cycles of B. tsuneonis remains scarce. Herein, several volatile chemicals including a γ-decalactone, (3R,4R)-3-hydroxy-4-decanolide [(3R,4R)-HD], were identified as major components, along with acetamide and spiroketals as minor components in the rectal gland complexes of male B. tsuneonis flies. The lactone (3R,4R)-HD was also identified in female rectal gland complexes. The amount of this compound in mature males was significantly higher than those observed in females and immature males. The lactone (3R,4R)-HD was detected in flies fed with sucrose only, indicating that this lactone is not derived from dietary sources during adulthood, but biosynthesized in vivo. The predominant accumulation of (3R,4R)-HD in mature males also suggests a possible role in reproductive behavior.


Assuntos
Lactonas/química , Glândula de Sal/química , Tephritidae/fisiologia , Acetamidas/síntese química , Acetamidas/química , Animais , Cromatografia Gasosa , Citrus , Dieta , Feminino , Furanos/síntese química , Furanos/química , Japão , Lactonas/síntese química , Masculino , Espectrometria de Massas , Reprodução/fisiologia , Atrativos Sexuais/química , Comportamento Sexual Animal/fisiologia , Compostos de Espiro/síntese química , Compostos de Espiro/química , Sacarose
6.
Eur J Med Chem ; 185: 111827, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31732256

RESUMO

Human African trypanosomiasis (HAT), caused by the parasitic protozoa Trypanosoma brucei, is one of the fatal diseases in tropical areas and current medicines are insufficient. Thus, development of new drugs for HAT is urgently needed. Leucyl-tRNA synthetase (LeuRS), a recently clinically validated antimicrobial target, is an attractive target for development of antitrypanosomal drugs. In this work, we report a series of α-phenoxy-N-sulfonylphenyl acetamides as T. brucei LeuRS inhibitors. The most potent compound 28g showed an IC50 of 0.70 µM which was 250-fold more potent than the starting hit compound 1. The structure-activity relationship was also discussed. These acetamides provided a new scaffold and lead compounds for the further development of clinically useful antitrypanosomal agents.


Assuntos
Acetamidas/farmacologia , Desenho de Drogas , Inibidores Enzimáticos/farmacologia , Leucina-tRNA Ligase/antagonistas & inibidores , Tripanossomicidas/farmacologia , Trypanosoma brucei brucei/efeitos dos fármacos , Acetamidas/síntese química , Acetamidas/química , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Leucina-tRNA Ligase/metabolismo , Estrutura Molecular , Testes de Sensibilidade Parasitária , Relação Estrutura-Atividade , Tripanossomicidas/síntese química , Tripanossomicidas/química , Trypanosoma brucei brucei/enzimologia
7.
Eur J Med Chem ; 185: 111866, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31734023

RESUMO

Introducing pyrimidine bases, the basic components of nucleic acid, to P2 ligands might enhance the potency of Human Immunodeficiency Virus-1 (HIV-1) protease inhibitors because of the carbonyl and amino groups promoting the formation of extensive hydrogen bonding interactions. In this work, we provide evidence that inhibitor 10e, with N-2-(2,4-Dioxo-3,4-dihydropyrimidin-1(2H)-yl) acetamide as the P2 ligand and a 4-methoxylphenylsulfonamide as the P2' ligand, displayed remarkable enzyme inhibitory and antiviral activity, with the IC50 2.53 nM in vitro and a promising inhibition ratio with 68% against wild-type HIV-1 in vivo, with low cytotoxicity. This inhibitor also exhibited appreciable antiviral activity against DRV-resistant HIV-1 variants, which was of great value for further study.


Assuntos
Acetamidas/farmacologia , Aminas/farmacologia , Fármacos Anti-HIV/farmacologia , Protease de HIV/metabolismo , HIV-1/efeitos dos fármacos , Inibidores de Proteases/farmacologia , Pirimidinas/farmacologia , Acetamidas/síntese química , Acetamidas/química , Aminas/síntese química , Aminas/química , Fármacos Anti-HIV/síntese química , Fármacos Anti-HIV/química , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Células HEK293 , HIV-1/enzimologia , Humanos , Ligantes , Testes de Sensibilidade Microbiana , Estrutura Molecular , Inibidores de Proteases/síntese química , Inibidores de Proteases/química , Pirimidinas/síntese química , Pirimidinas/química , Relação Estrutura-Atividade
8.
Eur J Med Chem ; 185: 111874, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31735575

RESUMO

The fragment hopping approach is widely applied in drug development. A series of diarylpyrimidines (DAPYs) were obtained by hopping the thioacetamide scaffold to novel human immunodeficiency virus type 1 (HIV-1) nonnucleoside reverse transcriptase inhibitors (NNRTIs) to address the cytotoxicity issue of Etravirine and Rilpivirine. Although the new compounds (11a-l) in the first-round optimization possessed less potent anti-viral activity, they showed much lower cytotoxicity. Further optimization on the sulfur led to the sulfinylacetamide-DAPYs exhibiting improved anti-viral activity and a higher selectivity index especially toward the K103N mutant strain. The most potent compound 12a displayed EC50 values of 0.0249 µM against WT and 0.0104 µM against the K103N mutant strain, low cytotoxicity (CC50 > 221 µM) and a high selectivity index (SI WT > 8873, SI K103N > 21186). In addition, this compound showed a favorable in vitro microsomal stability across species. Computational study predicted the binding models of these potent compounds with HIV-1 reverse transcriptase thus providing further insights for new developments.


Assuntos
Acetamidas/farmacologia , Fármacos Anti-HIV/farmacologia , Transcriptase Reversa do HIV/antagonistas & inibidores , HIV-1/efeitos dos fármacos , Pirimidinas/farmacologia , Inibidores da Transcriptase Reversa/farmacologia , Acetamidas/síntese química , Acetamidas/química , Fármacos Anti-HIV/síntese química , Fármacos Anti-HIV/química , Relação Dose-Resposta a Droga , Descoberta de Drogas , Transcriptase Reversa do HIV/metabolismo , HIV-1/enzimologia , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Pirimidinas/síntese química , Pirimidinas/química , Inibidores da Transcriptase Reversa/síntese química , Inibidores da Transcriptase Reversa/química , Relação Estrutura-Atividade
9.
Molecules ; 24(19)2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31575030

RESUMO

The Pd-catalyzed intramolecular carbene C-H insertion of α-diazo-α-(methoxycarbonyl)acetamides to prepare oxindoles as well as ß-lactams was studied. In order to identify what factors influence the selectivity of the processes, we explored how the reactions are affected by the catalyst type, using two oxidation states of Pd and a variety of ligands. It was found that, in the synthesis of oxindoles, ((IMes)Pd(NQ))2 can be used as an alternative to Pd2(dba)3 to catalyze the carbene CArsp2-H insertion, although it was less versatile. On the other hand, it was demonstrated that the Csp3-H insertion leading to ß-lactams can be effectively promoted by both Pd(0) and Pd(II) catalysts, the latter being most efficient. Insight into the reaction mechanisms involved in these transformations was provided by DFT calculations.


Assuntos
Acetamidas/química , Compostos de Diazônio/química , Paládio/química , Catálise , Modelos Moleculares , Estrutura Molecular , Oxindois/metabolismo , Paládio/metabolismo , beta-Lactamas/metabolismo
10.
Ecotoxicol Environ Saf ; 185: 109702, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31585394

RESUMO

The purpose of our work was to determine the acute and chronic toxicity of three of the EU's most common herbicides - mesotrione, S-metolachlor, terbuthylazine - and their mixtures by Aliivibrio fischeri ecotoxicological assays. While comparing the sensitivity of the acute (30 min) Microtox® standard assay with the chronic (25 h) test adapted to microtiter plate, joint effects (antagonism, additive effect and synergism) to the bioluminescence inhibition (consequently the metabolic damage) in A. fischeri were also determined by Combination Index (CI) method. 30 min of exposure to mesotrione and S-metolachlor resulted in a relatively low acute toxicity (EC50 values were 118 and 265 mg/L), while terbuthylazine did not cause bioluminescence inhibition at all. Results showed that the chronic toxicity of S-metolachlor and terbuthylazine to A. fischeri (EC5010h = 59.2 and 4.9 mg/L and EC5015h = 54.0 and 9.6 mg/L, respectively) is larger by at least one order of magnitude than that after 30 min of contact time. Considering mesotrione no significant difference was experienced in toxicity. Regarding the EC50 values, all of the mixtures had synergistic joint effects in the acute assay. However, in the chronic test all the mixtures showed antagonistic responses with the exception of mesotrione and S-metolachlor (ratio 1:1) combination, which also had additive and synergistic effects after 10 and 15 h of exposure, similarly to the short-term test. This is also the first report of the joint effects of these herbicides. The chronic test is a more sensitive indicator to the active ingredients; both acute and chronic assays supply valuable data of the toxic properties of the pesticides. Moreover, the short- and long-term joint effects of their mixtures supporting a more accurate and reliable risk assessment.


Assuntos
Acetamidas/toxicidade , Aliivibrio fischeri/efeitos dos fármacos , Cicloexanonas/toxicidade , Herbicidas/toxicidade , Triazinas/toxicidade , Poluentes Químicos da Água/toxicidade , Acetamidas/química , Bioensaio , Cicloexanonas/química , Relação Dose-Resposta a Droga , Ecotoxicologia , Herbicidas/química , Testes de Toxicidade Aguda , Testes de Toxicidade Crônica , Triazinas/química , Poluentes Químicos da Água/química
11.
J Chromatogr Sci ; 57(9): 769-777, 2019 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-31504301

RESUMO

Acetamide is a potential genotoxic impurity; it should control in drug substance based on daily dosage level. It forms from base-contaminated acetonitrile and by-product of some drug substances. The available methods for acetamide in drug substance and water samples were determined by GC-MS using internal standard with critical procedures. These developed and validated methods can assist in evaluating the reaction between acetonitrile and different bases and also determine trace level acetamide in drug substances. The method development was initiated with DB-624, 30 m, 0.32 width and 1.0-µm column. The column was used to validate at the 600 ppm TTC value. Similarly, the CP-SIL 5CB, 60 m, 0.32 width, the 5-µm column was used for the remaining TTC values. The validation study was performed for all TTC limits. The % RSD for precision at 600, 60, 20, 10 and 2.5 ppm was <15%. The % recovery at all TTC level was in between the 70 and 130%. Solution stability study was performed up to the 24 h. At 2.5 ppm, the results were <15% variation from the initial value. The linearities from the 50 to 150% concerning TTC values were more than limit of 0.98 correlation coefficient. The limit of detection and limit of quantitation values were 0.4 to the 1.3 ppm, respectively, for 2.5 ppm TTC limit method.


Assuntos
Acetamidas/análise , Acetonitrilos/análise , Contaminação de Medicamentos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Preparações Farmacêuticas/química , Acetamidas/química , Acetonitrilos/química , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes
12.
Eur J Med Chem ; 183: 111699, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31561045

RESUMO

The recent burst of explorations on heat shock protein 90 (HSP90) in virus research supports its emergence as a promising target to overcome the drawbacks of current antiviral therapeutic regimen. In continuation of our efforts towards the discovery of novel anti-retroviral molecules, we designed, synthesized fifteen novels 2-isoxazol-3-yl-acetamide based compounds (2a-o) followed by analysis of their anti-HIV activity and cytotoxicity studies. 2a-b, 2e, 2j, and 2l-m were found to be active with inhibitory potentials >80% at their highest non-cytotoxic concentration (HNC). Further characterization of anti-HIV activity of these molecules suggests that 2l has ∼3.5 fold better therapeutic index than AUY922, the second generation HSP90 inhibitor. The anti-HIV activity of 2l is a cell type, virus isolate and viral load independent phenomena. Interestingly, 2l does not significantly modulate viral enzymes like Reverse Transcriptase (RT), Integrase (IN) and Protease (PR) as compared to their known inhibitors in a cell free in vitro assay system at its HNC. Further, 2l mediated inhibition of HSP90 attenuates HIV-1 LTR driven gene expression. Taken together, structural rationale, modeling studies and characterization of biological activities suggest that this novel scaffold can attenuate HIV-1 replication significantly within the host and thus opens a new horizon to develop novel anti-HIV therapeutic candidates.


Assuntos
Acetamidas/farmacologia , Androstenóis/farmacologia , Fármacos Anti-HIV/farmacologia , Descoberta de Drogas , HIV-1/efeitos dos fármacos , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Acetamidas/síntese química , Acetamidas/química , Androstenóis/síntese química , Androstenóis/química , Fármacos Anti-HIV/síntese química , Fármacos Anti-HIV/química , Relação Dose-Resposta a Droga , HIV-1/metabolismo , Proteínas de Choque Térmico HSP90/metabolismo , Testes de Sensibilidade Microbiana , Estrutura Molecular , Relação Estrutura-Atividade , Replicação Viral/efeitos dos fármacos
13.
Molecules ; 24(18)2019 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-31547416

RESUMO

Various types of σ-hole bond complexes were formed with FX, HFY, H2FZ, and H3FT (X = Cl, Br, I; Y = S, Se, Te; Z = P, As, Sb; T = Si, Ge, Sn) as Lewis acid. In order to examine their interactions with a protein, N-methylacetamide (NMA), a model of the peptide linkage was used as the base. These noncovalent bonds were compared by computational means with H-bonds formed by NMA with XH molecules (X = F, Cl, Br, I). In all cases, the A-F bond, which lies opposite the base and is responsible for the σ-hole on the A atom (A refers to the bridging atom), elongates and its stretching frequency undergoes a shift to the red with a band intensification, much as what occurs for the X-H bond in a H-bond (HB). Unlike the NMR shielding decrease seen in the bridging proton of a H-bond, the shielding of the bridging A atom is increased. The spectroscopic changes within NMA are similar for H-bonds and the other noncovalent bonds. The C=O bond of the amide is lengthened and its stretching frequency red-shifted and intensified. The amide II band shifts to higher frequency and undergoes a small band weakening. The NMR shielding of the O atom directly involved in the bond rises, whereas the C and N atoms both undergo a shielding decrease. The frequency shifts of the amide I and II bands of the base as well as the shielding changes of the three pertinent NMA atoms correlate well with the strength of the noncovalent bond.


Assuntos
Calcogênios/química , Halogênios/química , Proteínas/química , Acetamidas/química , Hidrogênio/química , Ligações de Hidrogênio , Ácidos de Lewis/química , Ressonância Magnética Nuclear Biomolecular , Espectrofotometria Infravermelho
14.
Environ Sci Process Impacts ; 21(10): 1729-1735, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31478540

RESUMO

Soot is an important carbonaceous nanoparticle (CNP) frequently found in natural environments. Its entry into surface waters can occur directly via surface runoff or infiltration, as well as via atmospheric deposition. Pristine soot is likely to rapidly undergo aggregation and subsequent sedimentation in aquatic environments. Further, soot can sorb a variety of organic contaminants, such as S-metolachlor (log KD = 3.25 ± 0.12). During atmospheric transport, soot can be chemically transformed by reactive oxygen species including NO2. The presence of natural organic matter (NOM) in surface waters can further affect the aquatic fate of soot. To better understand the processes driving the fate of soot and its interactions with contaminants, pristine and NO2-transformed model soot suspensions were investigated in the presence and absence of NOM. NO2-oxidized soot showed a smaller particle size, a higher number of particles remaining in suspension, and a decreased sorption of S-metolachlor (log KD = 2.47 ± 0.40). In agreement with findings for other CNPs, soot stability against aggregation was increased for both pristine and NO2 transformed soot in the presence of NOM.


Assuntos
Acetamidas/química , Dióxido de Nitrogênio/química , Fuligem/química , Acetamidas/análise , Nanopartículas , Tamanho da Partícula , Fuligem/análise , Suspensões
15.
Molecules ; 24(16)2019 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-31409035

RESUMO

There have been developments in the optimization of polyether sulfone (PES) membranes, to provide antifouling and mechanically stable surfaces which are vital to water purification applications. There is a variety of approaches to prepare nanocomposite PES membranes. However, an optimized condition for making such membranes is in high demand. Using experimental design and statistical analysis (one-half fractional factorial design), this study investigates the effect of different parameters featured in the fabrication of membranes, as well as on the performance of a nanocomposite PES/TiO2 membrane. The optimized parameters obtained in this study are: exposure time of 60 s, immersion time above 10 h, glycerol time of 4 h, and a nonsolvent volumetric ratio (isopropanol/water) of 30/70 for PES and dimethylacetamide (PES-DMAc) membrane and 70/30 for PES and N-methyl-2-pyrrolidone (PES-NMP) membrane. A comparison of the contributory factors for different templating agents along with a nanocomposite membrane control, revealed that F127 triblock copolymer resulted in an excellent antifouling membrane with a higher bovine serum albumin rejection and flux recovery of 83.33%.


Assuntos
Nanocompostos/química , Polímeros/química , Sulfonas/química , Titânio/química , 2-Propanol/química , Acetamidas/química , Análise Fatorial , Glicerol/química , Humanos , Membranas Artificiais , Nanocompostos/ultraestrutura , Pirrolidinonas/química , Soroalbumina Bovina/química , Água/química , Purificação da Água/métodos
16.
Chemosphere ; 237: 124513, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31401429

RESUMO

The ability of contaminated farmland soils reclaimed by remediation to dissipate pesticides and thus to mitigate their unwanted environmental effects, i.e., leaching and run-off, was studied. Novel EDTA-based soil washing technology (EDTA and process waters recycling; no toxic emissions) removed 79 and 73% of Pb from acidic and calcareous soil with 740 and 2179 mg kg-1 Pb, respectively. The dissipation kinetics of four herbicides: mecoprop-P, isoproturon, bentazon and S-metolachlor was investigated under field conditions in beds with maize (Zea mays) and barley (Hordeum vulgare). The biphasic First-Order Multi-Compartment (FOMC) model was used to fit experimental data and calculate the herbicides' half-life (DT50) in soil. Remediation significantly (up to 64%) decreased dehydrogenase activity assessed as a marker of soil microbial activity and prolonged the DT50 of herbicides in acidic soils from 16% (isoproturon) to 111% (S-metachlor). Remediation had a less significant effect on herbicide dissipation in calcareous soils; i.e., mecoprop-P DT50 increased by 3%, while isoproturon and S-metachlor DT50 decreased by 29%. Overall, the dissipation from remediated soils was faster than the average DT50 of tested herbicides published in the Pesticides Properties DataBase. Results demonstrate that EDTA-based remediation of the studied soils does not pose any threat of extended herbicide persistence.


Assuntos
Ácido Edético/química , Herbicidas/análise , Metais Pesados/análise , Poluentes do Solo/análise , Ácido 2-Metil-4-clorofenoxiacético/análogos & derivados , Ácido 2-Metil-4-clorofenoxiacético/análise , Ácido 2-Metil-4-clorofenoxiacético/química , Acetamidas/análise , Acetamidas/química , Benzotiadiazinas/análise , Benzotiadiazinas/química , Recuperação e Remediação Ambiental , Herbicidas/química , Metais Pesados/química , Compostos de Fenilureia/análise , Compostos de Fenilureia/química , Solo/química , Microbiologia do Solo , Poluentes do Solo/química , Zea mays
17.
Environ Sci Pollut Res Int ; 26(26): 26706-26720, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31297708

RESUMO

Since decades, surface water bodies have been exposed to pesticides from agriculture. In many places, retention systems are regarded as an important mitigation strategy to lower pesticide pollution. Hence, the processes governing the transport of pesticides in and through a retention system have to be understood to achieve sufficient pesticide attenuation. In this study, the temporal dynamics of metazachlor and its transformation products metazachlor-oxalic acid (OA) and -sulphonic acid (ESA) were observed in an agricultural retention pond and hydrologic tracers helped to understand system-inherent processes. Pesticide measurements were carried out for 80 days after their application during transient flow conditions. During a short-term (3 days) experiment, the tracers bromide, uranine and sulphorhodamine B were used to determine hydraulic conditions, residence times and sorption potential. A long-term experiment with sodium naphthionate (2 months) and isotopes (12 months) provided information about inputs via interflow and surface-groundwater interactions. During transient conditions, high concentration pulses of up to 35 µg L-1 metazachlor, 14.7 µg L-1 OA and 22.5 µg L-1 ESA were quantified that enduringly raised solute concentrations in the pond. Mean residence time in the system accounted for approximately 4 h showing first tracer breakthrough after 5 min and last tracer concentrations 72 h after injection. While input via interflow was confirmed, no evidence for surface-groundwater interaction was found. Different tracers illustrated potentials for sorption and photolytic degradation inside the system. This study shows that high-resolution sampling is essential to obtain robust results about retention efficiency and that hydrological tracers may be used to determine the governing processes.


Assuntos
Acetamidas/análise , Herbicidas/análise , Hidrologia/métodos , Poluentes Químicos da Água/análise , Acetamidas/química , Agricultura , Biodegradação Ambiental , Brometos/análise , Fluoresceína/análise , Alemanha , Água Subterrânea , Herbicidas/química , Ácido Oxálico/química , Tanques , Rodaminas/análise , Ácidos Sulfônicos/química , Poluentes Químicos da Água/química , Poluição Química da Água/prevenção & controle
18.
Sci Total Environ ; 690: 181-188, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31288109

RESUMO

Agricultural chemicals are normally used as mixtures of several isomers, e.g., enantiomers. In theory, in order to minimize the pesticides dose, it is desirable to use the most target-active isomer. Metolachlor is a typical multichiral herbicide belonging to amide herbicides. An asymmetric carbon atom and a chiral axis yield four stereoisomers. In this study, a novel laboratory method was developed to prepare the S-metolachlor and the four stereoisomers using high performance liquid chromatography. The separated isomers had a purity of >99%, with their absolute configurations assigned by electronic circular dichroism. The enantioseparation by ultra performance convergence chromatography tandem mass spectrometry was also performed for the rapid and sensitive detection of metolachlor stereoisomers. The enantioselective herbicidal activity toward the target weed (Echinochloa crusgalli) was systematically assessed for the first time by measuring the morphology of the weed after treatment with rac-, S-metolachlor and the four stereoisomers, respectively. Among the commercial pesticides, S-metolachlor was more effective in weed inhibition than rac-metolachlor, and to the four stereoisomers, the herbicidal activities were ranked as: SS > SR ≫ RS > RR, and the RR-isomer even had some stimulative effect to the weed growth at lower concentration (1 ppm). Thus, we concluded that in these cases, the chiral carbon feature played a major role in herbicidal activity rather than the chiral axis feature, and the higher bioactivity of the S-isomers was confirmed by more effective uptake and stronger interaction with target enzymes that were involved in the gibberellic acid biosynthesis. Although the SS-isomer shows the highest herbicidal activity, controlling the major chiral feature is still much easier and more economical than controlling two chiral features.


Assuntos
Acetamidas/toxicidade , Agroquímicos/toxicidade , Echinochloa/efeitos dos fármacos , Herbicidas/toxicidade , Acetamidas/química , Agroquímicos/química , Relação Dose-Resposta a Droga , Herbicidas/química , Estereoisomerismo
19.
Environ Sci Pollut Res Int ; 26(25): 25874-25882, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31273652

RESUMO

Up-flow biological activated carbon (UBAC) filter has been widely used in waterworks due to its less hydraulic loss, stronger biodegradation ability, and the prevention of excessive biomass growth relative to down-flow BAC treatment. In this study, the different removal efficiency (DRE) of disinfection byproduct precursors between dichloroacetonitrile (DCAN) and dichloroacetamide (DCAcAm) was evaluated when UBAC filter was used as advanced treatment process. Results showed that the UBAC filter with approximately 36 months of usage time had a poor performance in the removal of DCAcAm formation potential (FP) (i.e. 9.3-19.1%) compared to DCAN FP (i.e., 22.5-34.1%). After chlorination of UBAC effluent, the hydrolysis of DCAN to form DCAcAm only partly contributed to the DRE variations of both DCAN FP and DCAcAm FP. Using the high-throughput sequencing technology and the redundancy analysis (RDA), the second dominant genus Bacillus in UBAC filter, which may transform precursors of DCAN into inorganic matters, could be another reason that led to the DRE in DCAN and DCAcAm FP. The formation and leakage of soluble microbial products (SMPs) was identified by excitation-emission matrix (EEM) peak intensities as well as variation of biological index (BIX). The SMPs released into UBAC effluent, favoring the formation of DCAcAm, also contributed to the precursors of both DCAN and DCAcAm, causing a poor removal performance in DCAcAm FP by UBAC filter.


Assuntos
Acetamidas/análise , Acetonitrilos/análise , Carvão Vegetal/química , Desinfecção/métodos , Acetamidas/química , Acetonitrilos/química , Biodegradação Ambiental , Halogenação
20.
Org Biomol Chem ; 17(33): 7694-7705, 2019 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-31328213

RESUMO

Membranous organelles are major endogenous sources of reactive oxygen and nitrogen species. When present at high levels, these species can cause macromolecular damage and disease. To better detect and scavenge free radical forms of the reactive species at their sources, we investigated whether nitrone spin traps could be selectively targeted to intracellular membranes using a bioorthogonal imaging approach. Electron paramagnetic resonance imaging demonstrated that the novel cyclic nitrone 5-dodecylcarbamoyl-5-N-dodecylacetamide-1-pyroline-N-oxide (diC12PO) could be used to target the nitrone moiety to liposomes composed of phosphatidyl choline. To test localization with authentic membranes in living cells, fluorophores were introduced via strain-promoted alkyne-nitrone cycloaddition (SPANC). Two fluorophore-conjugated alkynes were investigated: hexynamide-fluoresceine (HYA-FL) and dibenzylcyclooctyne-PEG4-5/6-sulforhodamine B (DBCO-Rhod). Computational and mass spectrometry experiments confirmed the cycloadduct formation of DBCO-Rhod (but not HYA-FL) with diC12PO in cell-free solution. Confocal microscopy of bovine aortic endothelial cells treated sequentially with diC12PO and DBCO-Rhod demonstrated clear localization of fluorescence with intracellular membranes. These results indicate that targeting of nitrone spin traps to cellular membranes is feasible, and that a bioorthogonal approach can aid the interrogation of their intracellular compartmentalization properties.


Assuntos
Acetamidas/química , Teoria da Densidade Funcional , Fluorescência , Imagem Óptica , Acetamidas/síntese química , Animais , Bovinos , Células Cultivadas , Espectroscopia de Ressonância de Spin Eletrônica , Estrutura Molecular
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