27 documents found, page 1 of 3
Assessing reactive oxygen and nitrogen species in atmospheric and aquatic envir...
Simões, Eliana F. C.; Almeida, Antoine S.; Duarte, Armando C.; Duarte, Regina M. B. O.Reactive oxygen and nitrogen species (ROS and RNS) play a crucial role in biotic and abiotic processes. In the atmosphere, ROS/RNS are usually associated with air pollution. The ability of certain air particulate matter constituents to influence the formation and cycling of ROS/RNS at the atmosphere-biosphere-hydrosphere interfaces is important for the observed linkages between atmospheric aerosols and adverse ...
Exploring water-soluble organic aerosols structures in urban atmosphere using a...
Duarte, Regina M. B. O.; Pu Duan; Jingdong Mao; Wenying Chu; Duarte, Armando C.; Schmidt-Rohr, KlausWater-soluble organic matter (WSOM) in air particles has profound effects on climate and human health. At the heart of this environmental significance of WSOM lies a complex set of compounds, of which a major fraction still often remains undeciphered. Yet, not all environmental problems require delving into the molecular-level identification of WSOM constituents. Understanding the contribution of different func...
Structural characterization of dissolved organic matter in permafrost peatland ...
Folhas, Diogo; Duarte, Armando C.; Pilote, Martin; Vincent, Warwick F.; Freitas, Pedro; Vieira, Gonçalo; Silva, Artur M. S.; Duarte, Regina M. B. O.Thermokarst lakes result from the thawing of ice-rich permafrost and are widespread across northern landscapes. These waters are strong emitters of methane, especially in permafrost peatland regions, where they are stained black by high concentrations of dissolved organic matter (DOM). In the present study, we aimed to structurally characterize the DOM from a set of peatland thermokarst lakes that are known to ...
Comprehensive multidimensional liquid chromatography for advancing environmenta...
Brandão, Pedro F.; Duarte, Armando C.; Duarte, Regina M. B. O.Chromatography is the separation method of choice in most laboratories worldwide. Nonetheless, the increasing need to decode complex samples has created a demand for better separation skills. The addition of extra separation dimensions to a conventional liquid chromatography system was one of the ways to answer to this demand. Although very common in proteomics and polymer research, the use of Multidimensional ...
Effect of soil organic matter, soil pH, and moisture content on solubility and ...
Gao, Xiaoyu; Rodrigues, Sónia M.; Spielman-Sun, Eleanor; Lopes, Sónia; Rodrigues, Sandra; Zhang, Yilin; Avellan, Astrid; Duarte, Regina M. B. O.The objectives of this research were to quantify the impact of organic matter content, soil pH and moisture content on the dissolution rate and solubility of copper oxide nanoparticles (CuO NPs) in soil, and to develop an empirical model to predict the dissolution kinetics of CuO NPs in soil. CuO NPs were dosed into standard LUFA soils with various moisture content, pH and organic carbon content. Chemical extra...
Structural features and pro-inflammatory effects of water-soluble organic matte...
Almeida, Antoine S.; Ferreira, Rita M. P.; Silva, Artur M. S.; Duarte, Armando C.; Neves, Bruno M.; Duarte, Regina M. B. O.The impact of inhalable fine particulate matter (PM2.5, aerodynamic diameter < 2.5 µm) on public health is of great concern worldwide. Knowledge on their harmful effects are mainly due to studies carried out with whole air particles, being the contribution of their different fractions largely unknown. Herein, a set of urban PM2.5 samples were collected during day and nighttime periods in Autumn and Spring, aimi...
Comparative study of atmospheric water-soluble organic aerosols composition in ...
Duarte, Regina M. B. O.; Piñeiro-Iglesias, Maria; López-Mahía, Purificación; Muniategui-Lorenzo, Soledad; Moreda-Piñeiro, Jorge; Silva, Artur M. S.This study investigates the structural composition and major sources of water-soluble organic matter (WSOM) from PM2.5 collected, in parallel, during summer and winter, in two contrasting suburban sites at Iberian Peninsula Coast: Aveiro (Portugal) and Coruña (Spain). PM10 samples were also collected at Coruña for comparison. Ambient concentrations of PM2.5, total nitrogen (TN), and WSOM were higher in Aveiro t...
Challenges in the identification and characterization of free amino acids and p...
Matos, Joao T. V.; Duarte, Regina M. B. O.; Duarte, Armando C.In the last decades, there has been an increasing interest in the presence of amino acids in atmospheric aerosols, either free or in combination (e.g., proteinaceous compounds). The fact that these compounds play an important role in the chemistry and physics of air particles and atmosphere, in atmosphere/biosphere nutrient cycling, and have a direct impact in human health has encouraged further studies. The di...
Two chemically distinct light-absorbing pools of urban organic aerosols: A comp...
Paula, Andreia S.; Matos, Joao T. V.; Duarte, Regina M. B. O.; Duarte, Armando C.The chemical and light-absorption dynamics of organic aerosols (OAs), a master variable in the atmosphere, have yet to be resolved. This study uses a comprehensive multidimensional analysis approach for exploiting simultaneously the compositional changes over a molecular size continuum and associated light-absorption (ultraviolet absorbance and fluorescence) properties of two chemically distinct pools of urban ...
Natural organic matter in urban aerosols: comparison between water and alkaline...
Matos, João T. V.; Freire, Sandra M. S. C.; Duarte, Regina M. B. O.; Duarte, Armando C.Understanding the complexity of Natural Organic Matter (NOM) in atmospheric aerosols has remained an important goal for the atmospheric research community. This work employs a Parallel Factor Model (PARAFAC) with Alternating Least Squares (ALS) algorithm to decompose and further compare sets of excitation-emission matrices fluorescence spectra of Water-soluble and Alkaline-soluble Organic Matter (WSOM and ASOM,...