Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Filtrar
Mais filtros











Base de dados
Intervalo de ano de publicação
1.
Sci Total Environ ; 815: 152880, 2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-34998760

RESUMO

Developing an accurate crop yield predicting system at a large scale is of paramount importance for agricultural resource management and global food security. Earth observation provides a unique source of information to monitor crops from a diversity of spectral ranges. However, the integrated use of these data and their values in crop yield prediction is still understudied. Here we proposed the combination of environmental data (climate, soil, geography, and topography) with multiple satellite data (optical-based vegetation indices, solar-induced fluorescence (SIF), land surface temperature (LST), and microwave vegetation optical depth (VOD)) into the framework to estimate crop yield for maize, rice, and soybean in northeast China, and their unique value and relative influence on yield prediction was assessed. Two linear regression methods, three machine learning (ML) methods, and one ML ensemble model were adopted to build yield prediction models. Results showed that the individual ML methods outperformed the linear regression methods, the ML ensemble model further improved the single ML models. Moreover, models with more inputs achieved better performance, the combination of satellite data with environmental data, which explained 72%, 69%, and 57% of maize, rice, and soybean yield variability, respectively, demonstrated higher yield prediction performance than individual inputs. While satellite data contributed to crop yield prediction mainly at the early-peak of the growing season, climate data offered extra information mainly at the peak-late season. We also found that the combined use of EVI, LST and SIF has improved the model accuracy compared to the benchmark EVI model. However, the optical-based vegetation indices shared similar information and did not provide much extra information beyond EVI. The within-season yield forecasting showed that crop yields can be satisfactorily forecasted at two to three months prior to harvest. Geography, topography, VOD, EVI, soil hydraulic and nutrient parameters are more important for crop yield prediction.


Assuntos
Agricultura , Produtos Agrícolas , Clima , Estações do Ano , Zea mays
2.
Molecules ; 25(18)2020 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-32962127

RESUMO

Novel imidazole derivatives were designed, prepared, and evaluated in vitro for antitumor activity. The majority of the tested derivatives showed improved antiproliferative activity compared to the positive control drugs 5-FU and MTX. Among them, compound 4f exhibited outstanding antiproliferative activity against three cancer cell lines and was considerably more potent than both 5-FU and MTX. In particular, the selectivity index indicated that the tolerance of normal L-02 cells to 4f was 23-46-fold higher than that of tumor cells. This selectivity was significantly higher than that exhibited by the positive control drugs. Furthermore, compound 4f induced cell apoptosis by increasing the protein expression levels of Bax and decreasing those of Bcl-2 in a time-dependent manner. Therefore, 4f could be a potential candidate for the development of a novel antitumor agent.


Assuntos
Antineoplásicos/síntese química , Apoptose/efeitos dos fármacos , Imidazóis/química , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Fluoruracila/farmacologia , Humanos , Imidazóis/síntese química , Imidazóis/farmacologia , Relação Estrutura-Atividade
3.
Bioorg Chem ; 99: 103837, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32299019

RESUMO

A novel of quarternary amine around a quinolinium iodide combined with even number alkyl chain were prepared in a several step in moderate yield starting from malonic ester and benzo[d][1,3]dioxol-5-amine. All of the active structure compounds were identified by nuclear magnetic resonance (NMR), such as 1H NMR, 13C NMR, infrared radiation (IR), high resolution mass spectrometry (HR-MS) and Carlo Erba Instruments CHNS-O EA1108 spectra analysis. With regard to the anticancer properties, the in vitro cytotoxicity against three human cancer cell lines (A-549, Hela and SGC-7901) were evaluated. The antibacterial properties against two human bacterial strains, Escherichia coli (ATCC 29213) and Staphylococcus aureus (ATCC 8739), along with minimum inhibitory concentration (MIC) values were evaluated. The target compounds, 5-12, exhibited significant antitumor and antibacterial activity, of which compound 12 was found to be the most potent derivative with IC50 values of 5.18 ± 0.64, 7.62 ± 1.05, 17.59 ± 0.41, and 54.45 ± 4.88 against A-549, Hela, SGC-7901, and L-02 cells, respectively, stronger than the positive control 5-FU and MTX. Furthermore, compound 12 had the most potent inhibitory activity. The MIC of this compound against Escherichia coli (ATCC 29213) and Staphylococcus aureus (ATCC 8739) was 3.125 nmol·mL-1, which was smaller than that of the reference agents, amoxicillin and ciprofloxacin.


Assuntos
Antibacterianos/farmacologia , Antineoplásicos/farmacologia , Desenho de Fármacos , Escherichia coli/efeitos dos fármacos , Quinolinas/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Antibacterianos/síntese química , Antibacterianos/química , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Quinolinas/síntese química , Quinolinas/química , Relação Estrutura-Atividade
4.
ChemMedChem ; 15(7): 600-609, 2020 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-32068948

RESUMO

A series of novel quinoline and quinolinium iodide derivatives were designed and synthesized to discover potential anticancer and antibacterial agents. With regard to anticancer properties, in vitro cytotoxicities against three human cancer cell lines (A-549, HeLa and SGC-7901) were evaluated. The antibacterial properties against two strains, Escherichia coli (ATCC 29213) and Staphylococcus aureus (ATCC 8739), along with minimum inhibitory concentration (MIC) values were evaluated. The target alkyliodine substituted compounds exhibited significant antitumor and antibacterial activity, of which compound 8-((4-(benzyloxy)phenyl)amino)-7-(ethoxycarbonyl)-5-propyl-[1,3]dioxolo[4,5-g]quinolin-5-ium (12) was found to be the most potent derivative with IC50 values of 4.45±0.88, 4.74±0.42, 14.54±1.96, and 32.12±3.66 against A-549, HeLa, SGC-7901, and L-02 cells, respectively, stronger than the positive controls 5-FU and MTX. Furthermore, compound 12 had the most potent bacterial inhibitory activity. The MIC of this compound against both E. coli and S. aureus was 3.125 nmol ⋅ mL-1 , which was smaller than that against the reference agents amoxicillin and ciprofloxacin.


Assuntos
Antibacterianos/farmacologia , Antineoplásicos/farmacologia , Desenho de Fármacos , Iodetos/farmacologia , Quinolinas/farmacologia , Compostos de Quinolínio/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Escherichia coli/efeitos dos fármacos , Humanos , Iodetos/síntese química , Iodetos/química , Testes de Sensibilidade Microbiana , Estrutura Molecular , Quinolinas/síntese química , Quinolinas/química , Compostos de Quinolínio/síntese química , Compostos de Quinolínio/química , Sais/síntese química , Sais/química , Sais/farmacologia , Staphylococcus aureus/efeitos dos fármacos
5.
J Enzyme Inhib Med Chem ; 34(1): 1210-1217, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31286781

RESUMO

In this study, a series of 4,5-bis(substituted phenyl)-4H-1,2,4-triazol-3-amine compounds was designed, synthesised, and evaluated to determine their potential as anti-lung cancer agents. According to the results of screening of lung cancer cell lines A549, NCI-H460, and NCI-H23 in vitro, most of the synthesised compounds have potent cytotoxic activities with IC50 values ranging from 1.02 to 48.01 µM. Particularly, compound 4,5-bis(4-chlorophenyl)-4H-1,2,4-triazol-3-amine (BCTA) was the most potent anti-cancer agent, with IC50 values of 1.09, 2.01, and 3.28 µM against A549, NCI-H460, and NCI-H23 cells, respectively, meaning many-fold stronger anti-lung cancer activity than that of the chemotherapeutic agent 5-fluorouracil. We also explored the effects of BCTA on apoptosis in lung cancer cells by flow cytometry and western blotting. Our results indicated that BCTA induced apoptosis by upregulating proteins BAX, caspase 3, and PARP. Thus, the potential application of compound BCTA as a drug should be further examined.


Assuntos
Aminas/química , Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Neoplasias Pulmonares/patologia , Triazóis/síntese química , Triazóis/farmacologia , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Espectroscopia de Prótons por Ressonância Magnética , Espectrometria de Massas por Ionização por Electrospray , Triazóis/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA