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

Base de dados
País/Região como assunto
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
J Environ Qual ; 43(1): 110-20, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25602545

RESUMO

Sediment transport is important for ecology and water quality in receiving waters. Physically based channel erosion methods were implemented in the Soil and Water Assessment Tool version 2009 (SWAT2009) to improve sediment concentration (SS) results. In the study, the default simplified Bagnold sediment routing method (EQN-0) and the physically based simplified Bagnold sediment routing method (EQN-1) were compared with Pareto fronts from multiobjective calibration. Two SWAT models using EQN-0 and EQN-1 were set up for a small agricultural Danish catchment and calibrated with multiobjective calibration on daily and weekly flow-weighted SS (WF SS). Results showed that the Pareto front of EQN-1 was slightly closer to the optimal point than EQN-0 in the objective space. Trade-off between WF SS and daily flow in EQN-1 was smaller than in EQN-0. The EQN-0 method generated more surface erosion to improve WF SS. The EQN-1 method generated more base flow to improve WF SS. The EQN-1 method was less dependent on surface erosion and simulated peak and low values of WF SS better than EQN-0. Therefore, EQN-1 is more suitable than EQN-0 in modeling SS in small lowland catchments.

2.
Foods ; 12(7)2023 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-37048236

RESUMO

In contrast to their well-known physiological properties, phytochemicals, such as flavonoids, have been less frequently examined for their physiochemical properties (e.g., surface activity). A natural quercetin self-stabilizing Pickering emulsion was fabricated and characterized in the present study. The antisolvent precipitation method was used to modify quercetin (in dihydrate form), and the obtained particles were characterized by light microscope, atom force microscope, XRD, and contact angle. The antisolvent treatment was found to reduce the particle size, crystallinity, and surface hydrophobicity of quercetin. We then examined the effects of the antisolvent ratio, particle concentration, and oil fraction on the properties of the quercetin particle-stabilized emulsions. In addition, increasing the antisolvent ratio (1:1~1:10) effectively improved the emulsification performance of the quercetin particles. The emulsion showed good storage stability, and the particle size of the emulsion decreased with the rising particle concentration and increased with the rising oil phase ratio. The findings indicate that natural quercetin treated with antisolvent method has a good ability to stabilize Pickering emulsion, and this emulsion may have good prospective application potential for the development of novel and functional emulsion foods.

3.
J Agric Food Chem ; 70(17): 5408-5416, 2022 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-35439006

RESUMO

Recently, Pickering emulsions stabilized by edible particles have attracted significant attention from the scientific community and food industry owing to their surfactant-free character. However, those edible particles are mostly used for stabilizing oil-in-water emulsions, whereas those for water-in-oil emulsions are very limited. In this article, stable water-in-oil Pickering emulsions were prepared through dispersing phytosterol particles in oil phase, and the effects of antisolvent treatment, the type of oil, particle concentration, and water fraction on the stability, type, and morphology of these emulsions were investigated. In addition, the release profile of salt as a model aqueous compound from these emulsions has also been studied. Results showed that due to its higher water content, the antisolvent pretreatment of phytosterol in the ethanol/water system facilitated the dispersion of dried phytosterol particles into oil phase as microcrystals. Water-in-oil Pickering emulsions with droplet sizes of 80-100 µm were fabricated at phytosterol concentrations of 1.5-3% w/v and water fractions of 0.2-0.6. The dissolved phytosterol molecules in oil phase could help in emulsion stabilization through interfacial crystallization during emulsification, evidenced by polar microscopic observations. Moreover, the salt release from phytosterol-stabilized Pickering emulsions showed a temperature-dependent profile which could have potential application in a controlled-release system. The current study provided important information for fabrication of stable water-in-oil emulsion using natural particles.


Assuntos
Fitosteróis , Água , Emulsões/química , Tamanho da Partícula , Cloreto de Sódio , Cloreto de Sódio na Dieta , Água/química
4.
Nat Ecol Evol ; 4(8): 1060-1068, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32541802

RESUMO

Climate and land-use change drive a suite of stressors that shape ecosystems and interact to yield complex ecological responses (that is, additive, antagonistic and synergistic effects). We know little about the spatial scales relevant for the outcomes of such interactions and little about effect sizes. These knowledge gaps need to be filled to underpin future land management decisions or climate mitigation interventions for protecting and restoring freshwater ecosystems. This study combines data across scales from 33 mesocosm experiments with those from 14 river basins and 22 cross-basin studies in Europe, producing 174 combinations of paired-stressor effects on a biological response variable. Generalized linear models showed that only one of the two stressors had a significant effect in 39% of the analysed cases, 28% of the paired-stressor combinations resulted in additive effects and 33% resulted in interactive (antagonistic, synergistic, opposing or reversal) effects. For lakes, the frequencies of additive and interactive effects were similar for all spatial scales addressed, while for rivers these frequencies increased with scale. Nutrient enrichment was the overriding stressor for lakes, with effects generally exceeding those of secondary stressors. For rivers, the effects of nutrient enrichment were dependent on the specific stressor combination and biological response variable. These results vindicate the traditional focus of lake restoration and management on nutrient stress, while highlighting that river management requires more bespoke management solutions.


Assuntos
Ecossistema , Água Doce , Biota , Europa (Continente) , Rios
5.
Psychol Res Behav Manag ; 3: 65-74, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-22110330

RESUMO

The present study investigates the relationship of expression recognition and affective experience during facial expression processing by event-related potentials (ERP). Facial expressions used in the present study can be divided into three categories: positive (happy), neutral (neutral), and negative (angry). Participants were asked to finish two kinds of facial recognition tasks: one was easy, and the other was difficult. In the easy task, significant main effects were found for different valence conditions, meaning that emotions were evoked effectively when participants recognized the expressions in facial expression processing. However, no difference was found in the difficult task, meaning that even if participants had identified the expressions correctly, no relevant emotion was evoked during the process. The findings suggest that emotional experience was not simultaneous with expression identification in facial expression processing, and the affective experience process could be suppressed in challenging cognitive tasks. The results indicate that we should pay attention to the level of cognitive load when using facial expressions as emotion-eliciting materials in emotion studies; otherwise, the emotion may not be evoked effectively.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA