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1.
Ecotoxicol Environ Saf ; 208: 111738, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396066

RESUMO

With an ever-increasing number of synthetic chemicals being manufactured, it is unrealistic to expect that they will all be subjected to comprehensive and effective risk assessment. A shift from conventional animal testing to computer-aided methods is therefore an important step towards advancing the environmental risk assessments of chemicals. The aims of this study are two-fold: firstly, it examines the relationships between structural and physicochemical features of a diverse set of organic chemicals, and their acute aquatic toxicity towards Daphnia magna and Oryzias latipes using a classification tree approach. Secondly, it compares the efficiency and accuracy of the predictions of two modeling schemes: local models that are inherently restricted to a smaller subset of structurally-related substances, and a global model that covers a wider chemical space and a number of modes of toxic action. The classification tree-based models differentiate the organic chemicals into either 'highly toxic' or 'low to non-toxic' classes, based on internal and external validation criteria. These mechanistically-driven models, which demonstrate good performance, reveal that the key factors driving acute aquatic toxicity are lipophilicity, electrophilic reactivity, molecular polarizability and size. A comparative analysis of the performance of the two modeling schemes indicates that the local models, trained on homogeneous data sets, are less error prone, and therefore superior to the global model. Although the global models showed worse performance metrics compared to the local ones, their applicability domain is much wider, thereby significantly increasing their usefulness in practical applications for regulatory purposes. This demonstrates their advantage over local models and shows they are an invaluable tool for modeling heterogeneous chemical data sets.


Assuntos
Testes de Toxicidade/métodos , Poluentes Químicos da Água/toxicidade , Animais , Daphnia/efeitos dos fármacos , Compostos Orgânicos/toxicidade , Relação Quantitativa Estrutura-Atividade , Medição de Risco
2.
Water Res ; 192: 116843, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33494041

RESUMO

Due to the increasing diversity of organic contaminants discharged into anoxic water environments, reactivity prediction is necessary for chemical persistence evaluation for water treatment and risk assessment purposes. Almost all quantitative structure activity relationships (QSARs) that describe rates of contaminant transformation apply only to narrowly-defined, relatively homogenous families of reactants (e.g., dechlorination of alkyl halides). In this work, we develop predictive models for abiotic reduction of 60 organic compounds with diverse reducible functional groups, including nitroaromatic compounds (NACs), aliphatic nitro-compounds (ANCs), aromatic N-oxides (ANOs), isoxazoles (ISXs), polyhalogenated alkanes (PHAs), sulfoxides and sulfones (SOs), and others. Rate constants for their reduction were measured using a model reductant system, Fe(II)-tiron. Qualitatively, the rates followed the order NACs > ANOs ≈ ISXs ≈ PHAs > ANCs > SOs. To develop QSARs, both conventional chemical descriptor-based and machine learning (ML)-based approaches were investigated. Conventional univariate QSARs based on a molecular descriptor ELUMO (energy of the lowest-unoccupied molecular orbital) gave good correlations within classes. Multivariate QSARs combining ELUMO with Abraham descriptors for physico-chemical properties gave slightly improved correlations within classes for NCs and NACs, but little improvement in correlation within other classes or among classes. The ML model obtained covers reduction rates for all classes of compounds and all of the conditions studied with the prediction accuracy similar to those of the conventional QSARs for individual classes (r2 = 0.41-0.98 for univariate QSARs, 0.71-0.94 for multivariate QSARs, and 0.83 for the ML model). Both approaches required a scheme for a priori classification of the compounds for model training. This work offers two alternative modeling approaches to comprehensive abiotic reactivity prediction for persistence evaluation of organic compounds in anoxic water environments.


Assuntos
Compostos Orgânicos , Relação Quantitativa Estrutura-Atividade , Compostos Ferrosos , Humanos , Aprendizado de Máquina , Água
3.
Toxicol Lett ; 340: 77-88, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33412251

RESUMO

Species within the viperid genus Macrovipera are some of the most dangerous snakes in the Eurasian region, injecting copious amounts of potent venom. Despite their medical importance, the pathophysiological actions of their venoms have been neglected. Particularly poorly known are the coagulotoxic effects and thus the underlying mechanisms of lethal coagulopathy. In order to fill this knowledge gap, we ascertained the effects of venom upon human plasma for Macrovipera lebetina cernovi, M. l. lebetina, M. l. obtusa, M. l. turanica, and M. schweizeri using diverse coagulation analysing protocols. All five were extremely potent in their ability to promote clotting but varied in their relative activation of Factor X, being equipotent in this study to the venom of the better studied, and lethal, species Daboia russelii. The Insoserp European viper antivenom was shown to be highly effective against all the Macrovipera venoms, but performed poorly against the D. russelii venom. Reciprocally, while Daboia antivenoms performed well against D. russelii venom, they failed against Macrovipera venom. Thus despite the two genera sharing a venom phenotype (Factor X activation) driven by the same toxin type (P-IIId snake venom metalloproteases), the surface biochemistries of the toxins differed significantly enough to impede antivenom cross- neutralization. The differences in venom biochemistry were reflected in coagulation co-factor dependence. While both genera were absolutely dependent upon calcium for the activation of Factor X, dependence upon phospholipid varied. The Macrovipera venoms had low levels of dependence upon phospholipid while the Daboia venom was three times more dependent upon phospholipid for the activation of Factor X. This suggests that the sites on the molecular surface responsible for phospholipid dependence, are the same differential sites that prevent inter-genera antivenom cross- neutralization. Due to cold-chain requirements, antivenoms may not be stocked in rural settings where the need is at the greatest. Thus we tested the efficacy of enzyme inhibitor Prinomastat as a field-deployable treatment to stabilise patients while being transported to antivenom stocks, and showed that it was extremely effective in blocking the Factor X activating pathophysiological actions. Marimastat however was less effective. These results thus not only shed light on the coagulopathic mechanisms of Macrovipera venoms, but also provide data critical for evidence-based design of snakebite management strategies.


Assuntos
Coagulação Sanguínea/efeitos dos fármacos , Venenos de Víboras/toxicidade , Viperidae/fisiologia , Animais , Antivenenos/farmacologia , Fator X/química , Fator X/metabolismo , Humanos , Ácidos Hidroxâmicos/farmacologia , Inibidores de Metaloproteinases de Matriz/farmacologia , Compostos Orgânicos/farmacologia , Fosfolipídeos/química , Especificidade da Espécie
4.
Sci Rep ; 11(1): 2224, 2021 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-33500453

RESUMO

Phylogenetic analysis has demonstrated that the etiologic agent of the 2020 pandemic outbreak is a betacoronavirus named SARS-CoV-2. For public health interventions, a diagnostic test with high sensitivity and specificity is required. The gold standard protocol for diagnosis by the Word Health Organization (WHO) is RT-PCR. To detect low viral loads and perform large-scale screening, a low-cost diagnostic test is necessary. Here, we developed a cost-effective test capable of detecting SARS-CoV-2. We validated an auxiliary protocol for molecular diagnosis with the SYBR Green RT-PCR methodology to successfully screen negative cases of SARS-CoV-2. Our results revealed a set of primers with high specificity and no homology with other viruses from the Coronovideae family or human respiratory tract pathogenic viruses, presenting with complementarity only for rhinoviruses/enteroviruses and Legionella spp. Optimization of the annealing temperature and polymerization time led to a high specificity in the PCR products. We have developed a more affordable and swift methodology for negative SARS-CoV-2 screening. This methodology can be applied on a large scale to soften panic and economic burden through guidance for isolation strategies.


Assuntos
/métodos , Compostos Orgânicos , Reação em Cadeia da Polimerase em Tempo Real/métodos , DNA de Cadeia Simples , Enterovirus , Genoma Viral , Humanos , Filogenia , Reação em Cadeia da Polimerase , Rhinovirus , Sensibilidade e Especificidade , Temperatura , Carga Viral
5.
Nat Commun ; 12(1): 218, 2021 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-33431882

RESUMO

Development of organic theranostic agents that are active in the second near-infrared (NIR-II, 1000-1700 nm) biowindow is of vital significance for treating deep-seated tumors. However, studies on organic NIR-II absorbing agents for photo-to-heat energy-converting theranostics are still rare simply because of tedious synthetic routes to construct extended π systems in the NIR-II region. Herein, we design a convenient strategy to engineer highly stable organic NIR-II absorbing theranostic nanoparticles (Nano-BFF) for effective phototheranostic applications via co-assembling first NIR (NIR-I, 650-1000 nm) absorbing boron difluoride formazanate (BFF) dye with a biocompatible polymer, endowing the Nano-BFF with remarkable theranostic performance in the NIR-II region. In vitro and in vivo investigations validate that Nano-BFF can serve as an efficient theranostic agent to achieve photoacoustic imaging guided deep-tissue photonic hyperthermia in the NIR-II biowindow, achieving dramatic inhibition toward orthotopic hepatocellular carcinoma. This work thus provides an insight into the exploration of versatile organic NIR-II absorbing nanoparticles toward future practical applications.


Assuntos
Temperatura Alta , Raios Infravermelhos , Luz , Compostos Orgânicos/química , Nanomedicina Teranóstica , Animais , Linhagem Celular Tumoral , Formazans/administração & dosagem , Formazans/farmacocinética , Camundongos Endogâmicos C57BL , Neoplasias/patologia , Neoplasias/terapia , Técnicas Fotoacústicas
6.
Ecotoxicol Environ Saf ; 208: 111689, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396021

RESUMO

Gunshot residue (GSR) stemming from the discharge of firearms has been essential to advancements in the field of forensic science however the human and environmental health impacts from GSR are far less researched. GSR represents a multifaceted concern: it contains a complex mixture of inorganic and organic components and produces airborne particles with variable sizes, depositions, and fates. Herein we evaluate studies in the literature examining GSR collection, deposition, composition, environmental contamination, and potential remediation techniques within the last two decades (2000 - 2020). Throughout we reflect upon key findings and weaknesses in relation to environmental characterization of GSR and associated firearm contaminants. Research focused on techniques to analyze both inorganic and organic GSR simultaneously has begun, but requires additional effort. A vast majority of the available environmental characterization literature focuses on soil contamination at outdoor firing ranges for a select number of elements (Cu, Pb, Sb) with comparisons between ranges or at different collection distances and depths. There is limited ability for between study comparisons due to collection and analysis differences as well as a lack of background soil sampling. Notably, these studies lack direct quantification of the contribution of contaminants from GSR as well as analysis of organic compounds. Currently, there is a need for air monitoring to determine the composition, deposition, and fate of GSR, particularly in outdoor settings. This review summarizes the collection, characterization, and environmental studies related to GSR and highlights areas of research needed to establish the environmental health impacts.


Assuntos
Poluentes Ambientais , Poluição Ambiental/análise , Recuperação e Remediação Ambiental/métodos , Armas de Fogo , Animais , Antimônio/análise , Poluentes Ambientais/análise , Poluentes Ambientais/química , Poluição Ambiental/prevenção & controle , Humanos , Chumbo/análise , Compostos Orgânicos/análise
7.
Sci Total Environ ; 763: 142937, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33498124

RESUMO

The properties and composition of soil dissolved organic matter (DOM) are highly affected by the adsorption and desorption of organic matter (OM) on soil minerals and heterotrophic microbial respiration. Organic acids (e.g., oxalic acid), components of root exudates, have been revealed to liberate organic matter (OM) by the dissolution of protective mineral phases and stimulate microbial degradation of OM. However, the effects of organic acids on the properties and composition of soil DOM molecules and the related mechanisms are still poorly understood. In this study, we conducted microcosm incubation experiments with and without oxalic acid addition, and aimed to elucidate the variations of DOM properties and composition, employing a combination of Fourier transform ion cyclotron resonance mass spectrometry, optical spectroscopy, and bacterial community composition analysis. Our results indicated that the released OM from the direct dissolution of protective mineral phases by oxalic acid further stimulated the microbial reductive release of Fe mineral-associated OM under anoxic conditions. Furthermore, the addition of oxalic acid enhanced the degradation of aliphatic compounds and lignins with low O/C ratios, and increased the accumulation of lignins with high O/C ratios, tannins, and condensed aromatics. Linking the bacterial community composition to DOM molecular properties and composition further suggested that the enhanced reductive release of Fe mineral-associated OM was highly related to the increased abundances of Proteobacteria and Actinobacteria. Overall, oxalic acid induced long-lasting impacts on soil DOM properties and composition under anoxic soil conditions in our study. We expect that our results will contribute to understanding the dynamics of soil DOM molecules in the environment.


Assuntos
Ácido Oxálico , Solo , Adsorção , Minerais , Compostos Orgânicos
8.
Anal Chem ; 93(3): 1498-1506, 2021 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-33355455

RESUMO

The identity of an unknown environmental pollutant is reflected by the mass and dissociation chemistry of its (quasi)molecular ion. Gas chromatography-atmospheric pressure chemical ionization-mass spectrometry (GC-APCI-MS) increases the yield of molecular ions (compared to conventional electron ionization) by collisional cooling. Scanning quadrupole data-independent acquisition (SQDIA) permits unbiased, unattended selection of (quasi)molecular ions and acquisition of structure-diagnostic collision-induced dissociation mass spectra, while minimizing interferences, by sequentially cycling a quadrupole isolation window through the m/z range. This study reports on the development of a suspect screening method based on industrial compounds with bioaccumulation potential. A comparison of false and correct identifications in a mixed standard containing 30 analytes suggests that SQDIA results in a markedly lower false-positive rate than standard DIA: 5 for SQDIA and 82 for DIA. Electronic waste dust was analyzed using GC and quadrupole time-of-flight MS with APCI and SQDIA acquisition. A total of 52 brominated, chlorinated, and organophosphorus compounds were identified by suspect screening; 15 unique elemental compositions were identified using nontargeted screening; 17 compounds were confirmed using standards and others identified to confidence levels 2, 3, or 4. SQDIA reduced false-positive identifications, compared to experiments without quadrupole isolation. False positives also varied by class: 20% for Br, 37% for Cl, 75% for P, and >99% for all other classes. The structure proposal of a previously reported halogenated compound was revisited. The results underline the utility of GC-SQDIA experiments that provide information on both the (quasi)molecular ions and its dissociation products for a more confident structural assignment.


Assuntos
Pressão Atmosférica , Poluentes Ambientais/análise , Compostos Orgânicos/análise , Cromatografia Gasosa-Espectrometria de Massas , Estrutura Molecular
9.
Sci Total Environ ; 754: 142103, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32920394

RESUMO

The degradation potential of micropollutants and transformation products in biological post-treatment after ozonation is partly unknown. A pilot plant with ozonation and subsequent biological treatment in a moving bed biofilm reactor (MBBR) was thus operated over 16 months to investigate the removal of micropollutants and the formation and removal of N-oxide transformation products. Lab-scale kinetic experiments were performed in parallel. At a moderate ozone dose of 0.5 g O3 g-1 DOC, further degradation of gabapentin and 3 iodinated contrast media (iomeprol, iopamidol, and iohexol) could be induced by the biofilm at prolonged exposure times. To facilitate comparison of feeding regimens in biofilm systems a new surface-related degradation rate constant was introduced. The availability of substrates in the pilot MBBR influenced the micropollutant degradation kinetics with increasing and decreasing degradation rates. N-oxides from erythromycin, clarithromycin, tramadol, and venlafaxine were formed during ozonation and could not be degraded by the biofilm.


Assuntos
Ozônio , Poluentes Químicos da Água , Biofilmes , Reatores Biológicos , Compostos Orgânicos , Eliminação de Resíduos Líquidos , Águas Residuárias/análise , Poluentes Químicos da Água/análise
10.
Food Chem ; 338: 127932, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32932080

RESUMO

An efficient and reliable duplex SYBR Green real-time quantitative PCR (qPCR) method for beef products adulteration detection was developed based on bovine specific and vertebrate universal primers. By analyzing the numbers, positions (Tm value) of melting curve peaks of the duplex PCR products, we simultaneously identified bovine and preliminary screened non-bovine in samples, and also semi-quantified the bovine percentage according to the area ratios of peaks. All of these were necessary for adulteration determination. The specific and universal primers were designed based on mitochondrial genes ND4 and 16S rRNA respectively, their amplicons Tm values were 72.6 ± 0.5 °C and 79-81 °C. There might be some other peaks at 74-78 °C and above 81 °C if non-bovine components existed. Thelimit of detectionwas 1 pgforbovineDNA, and1 - 30 pg fornon-bovineDNAbasedon differentspecies.


Assuntos
Compostos Orgânicos/metabolismo , Reação em Cadeia da Polimerase em Tempo Real/métodos , Carne Vermelha/análise , Animais , Bovinos , Primers do DNA/genética , Qualidade dos Alimentos
11.
Artigo em Inglês | MEDLINE | ID: mdl-33378253

RESUMO

Wastewater reuse has been widely discussed as an essential strategy to minimize the consumption of drinking water for less noble purposes. During biological wastewater treatment, organic matter is converted into a complex matrix containing a variety of soluble organic compounds. The objective of the present study was to evaluate the removal efficiency of the residual organic load in the final effluent from wastewater treatment plant with a conventional activated sludge process by different coagulants and parameters of coagulation-flocculation process, using dissolved organic carbon (DOC) concentration, molecular weight (MW) size distribution by size exclusion chromatography (SEC) coupled to mass spectrometry (MS), and zeta potential (ZP) analyses. The results showed a DOC removal efficiency up to 45% with iron chloride, and of 38% for aluminum sulfate and 31% for PAC coagulants. ZP was also measured during the procedures and authors conclude that the ZP also does not have a determining role in these removals. SEC and MS assessment was able to detect changes on secondary effluent molecular weight distribution profile after effluent coagulation-flocculation, this technique might be a promising tool to understand the composition of effluent organic matter and be helpful to estimate and optimize the performance of wastewater effluents treatment processes.


Assuntos
Floculação , Compostos Orgânicos/análise , Esgotos/química , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Purificação da Água/métodos , Compostos de Alúmen/química , Análise da Demanda Biológica de Oxigênio , Solubilidade
12.
Gene ; 767: 145178, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-33007378

RESUMO

Telomeres are highly repetitive regions capping the chromosomes and composed of multiple units of hexa-nucleotides, TTAGGG, making their quantification difficult. Most of the methods developed to estimate telomeres are extensively cumbersome or expensive. The quantitative polymerase chain reaction (qPCR) based assay is relatively easy and cheaper method that applies SyBr Green dye chemistry to measure telomere length. SyBr Green dye fluoresces after intercalation into the double stranded DNA (dsDNA), thus detection of unspecific products has been a limitation as it may affect quantitation of telomeres. To overcome this limitation of SyBr Green dye, we developed a dual labeled fluorescence probe based quantitative polymerase chain reaction (qPCR) to measure the telomere length. This highly efficient, yet cost effective and easy method, utilizes a probe that targets primarily the telomeric DNA and this increases accuracy of an existing qPCR method.


Assuntos
Reação em Cadeia da Polimerase/métodos , Telômero/genética , Telômero/metabolismo , DNA/genética , Fluorescência , Corantes Fluorescentes/química , Corantes Fluorescentes/metabolismo , Humanos , Hibridização in Situ Fluorescente/métodos , Compostos Orgânicos/química , Sequências Repetitivas de Ácido Nucleico/genética , Homeostase do Telômero/genética
13.
J Chromatogr A ; 1636: 461792, 2021 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-33340747

RESUMO

Chiral metal-organic cages (MOCs) are a new type of porous materials with unique molecular recognition ability, which have received research attention as a chiral stationary phase (CSP) for gas chromatography (GC). Herein, we report the detailed investigation of a chiral MOC ([Cu12(LPA)12(H2O)12], PA = L-phenylalanine, MOC-PA) as a novel stationary phase for GC separations. The MOC-PA capillary column exhibited a high-resolution performance for a wide range of analytes, including n-alkanes, n-alcohols, esters, aromatic compounds and the Grob mixture, positional isomers and racemates. In particular, MOC-PA coated column displayed good resolution and performance for amino acid derivatives. Moreover, the MOC-PA column showed excellent separation repeatability and reproducibility. The relative standard deviation (RSD) values for the retention times were in the range of 0.16-0.30% for run to run (n = 3), 0.31-0.77% for day-to-day (n = 3), and 3.6-4.7% for column-to-column (n = 3), respectively. The experimental results showed that MOC-PA had great potential as a GC stationary phase.


Assuntos
Cromatografia Gasosa/métodos , Metais/química , Compostos Orgânicos/química , Álcoois/química , Alcanos/química , Ésteres/química , Fenilalanina/química , Reprodutibilidade dos Testes , Espectroscopia de Infravermelho com Transformada de Fourier , Estereoisomerismo , Termogravimetria , Difração de Raios X
14.
Chemosphere ; 262: 127806, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32750591

RESUMO

In the view of green and efficient removal of chromium pollution, uniform fiber ball loaded with Fe(OH)3 (UFB-Fe(OH)3), was firstly synthesized and successfully used in the photoreduction of Cr(VI) by oxalate acid (Ox). The Cr(VI) removal in UFB-Fe(OH)3+Ox + UV system was examined by the effect of concentration of Ox, initial Cr(VI) concentration, dosage of UFB-Fe(OH)3 and the reusability of UFB-Fe(OH)3. By studying the impact of the initial pH in the solution, the relationship between the change in pH during the reaction and the removal efficiency of Cr(VI), the effect of coexisting ion (NO3-), and the free radicals quenching tests, the Cr(VI) removal mechanism in UFB-Fe(OH)3+Ox + UV system was further deduced. The results showed that UFB-Fe(OH)3 could greatly enhance the photoreduction of Cr(VI) by Ox, 1.5 mM Cr(VI) was completely removed in 6 min by UFB-Fe(OH)3+Ox + UV system. UFB-Fe(OH)3 had the feasibility of multiple use, it still exhibited the excellent enhancement in Cr(VI) removal by Ox after six cycles of use. The Cr(VI) photoreduction mechanism was consist of three part: i) Ox generate a part of CO2·- under the ultraviolet (UV) to reduce Cr(VI); ii) the Fe(III) dissolved by UFB-Fe(OH)3 formed FeOH2+ in the solution, and then generated very little Fe(II) under UV to remove Cr(VI); iii) the synergistic effect of UFB-Fe(OH)3 and Ox rapidly generated a large number of CO2·- and Fe(II) under UV excitation to reduce Cr(VI).


Assuntos
Cromo/química , Oxalatos/química , Poluentes Químicos da Água/química , Cromo/toxicidade , Ferro , Compostos Orgânicos , Oxirredução , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
15.
Food Chem ; 336: 127679, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32768903

RESUMO

This study investigated the effect of aqueous fat separation and defatting using organic solvents (99% methanol, ethanol, and n-hexane) on the characteristics and functionality of proteins extracted from Protaetia brevitarsis. The defatting efficiency, amino acid composition, protein solubility, and technical properties were the highest when proteins were defatted using n-hexane. Proteins defatted using ethanol were similar in foam capacity and emulsifying capacity. Surface hydrophobicity decreased when using organic solvents, and excessive fat content disrupted the functional properties of the extracted proteins. Proteins extracted using the different solvents displayed different pH values. The pH of the aqueous extract was the lowest. CIE L* a* b* color values also differed using the different extraction methods. Although n-hexane might be the most efficient solvent for defatting the proteins extracted from edible insects, ethanol could also be used to obtain similar foam and emulsifying capacities.


Assuntos
Besouros/química , Proteínas de Insetos/isolamento & purificação , Proteínas de Insetos/metabolismo , Larva/química , Compostos Orgânicos/química , Solventes/química , Aminoácidos/química , Animais , Ácidos Graxos/química , Interações Hidrofóbicas e Hidrofílicas , Proteínas de Insetos/química , Solubilidade
16.
Sci Total Environ ; 750: 141762, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32877789

RESUMO

Sulfonamides (SAs) are ubiquitous antibiotics that are increasingly detected in the aquatic environment, and may cause potential harm to the environment and humans. Indirect photodegradation has been considered to be a promising natural degradation process for antibiotics in the environment. Chromophoric dissolved organic matter (CDOM) is an important participant in the indirect photodegradation of antibiotics. Indirect photodegradation of sulfathiazole (ST) and sulfamerazine (SM) were studied in the presence of CDOM and marine factors (salinity, pH, nitrate (NO3-) and bicarbonate (HCO3-)) to simulate photodegradation of these compounds in the coastal seawater environment. The main findings are as follows. First, the indirect photodegradation rates of ST and SM in the presence of CDOM were significantly increased and followed the pseudofirst order kinetics. Second, 1O2 played a critical role in the indirect photodegradation of ST and its contribution rate was 54.2%; 3CDOM⁎ performed similarly in the case of SM with a 58.0% contribution rate. Third, CDOM was divided into four fluorescent components by excitation-emission matrix spectroscopy and parallel factor analysis (EEMs-PARAFAC), including three exogenous components and an autochthonous component. The exogenous components with high molecular weight and higher number of aromatic groups played a decisive role in the indirect photodegradation of ST and SM due to their ability to generate higher levels of reactive intermediates (RIs). Finally, seawater factors (salinity, pH, NO3- and HCO3-) influenced the indirect photodegradation of ST and SM by influencing the steady-state concentrations of RIs. This report is the first study of indirect photodegradation of ST and SM from the perspective of the CDOM components and simulated coastal waters.


Assuntos
Salinidade , Sulfamerazina , Bicarbonatos , Humanos , Concentração de Íons de Hidrogênio , Compostos Orgânicos , Fotólise , Água do Mar , Espectrometria de Fluorescência , Sulfatiazóis
17.
Sci Total Environ ; 752: 142001, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32892057

RESUMO

Generally, human oral exposure assessments of contaminants have not considered the absorption factor in the human gastrointestinal tract, thus overestimating human exposure and associated health risk. Currently, more researchers are adding the absorption factor into human exposure assessment, and bioaccessibility measured by in-vitro methods is generally replacing bioavailability for estimation because of the cheap and rapid determination. However, no single unified in-vitro method is used for bioaccessibility measurement of organic pollutants, although several methods have been developed for these pollutants and have shown good in vitro-in vivo correlation between bioaccessibility and bioavailability. The present review has focused on the development of in-vitro methods, validation of these methods through in-vivo assays, determination of factors influencing bioaccessibility, application of bioaccessibility in human exposure assessment, and the challenges faced. Overall, most in-vitro methods were validated using bioavailability, and better in vitro-in vivo correlations were obtained when absorption sinks were added to the digestion solution to mimic dynamic absorption of organic chemicals by small intestine. Incorporating bioaccessibility into the estimation of human exposure by oral ingestion significantly decreases the estimated exposure dose. However, more investigations on bioaccessibility of hydrophobic organic compounds are urgently needed because many challenges for in-vitro methods remain to be overcome.


Assuntos
Poluentes Ambientais , Poluentes do Solo , Disponibilidade Biológica , Humanos , Técnicas In Vitro , Compostos Orgânicos , Medição de Risco , Poluentes do Solo/análise
18.
Food Chem ; 339: 128063, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33152865

RESUMO

Dicarbonyls are reactive precursors of advanced glycation endproducts. They are formed endogenously and during food processing. Currently, a comprehensive database on dicarbonyls in foods that covers the entire range of food groups is lacking, limiting knowledge about the amount of dicarbonyls that is ingested via food. The aim of this study was to analyze the dicarbonyls methylglyoxal (MGO), glyoxal (GO), and 3-deoxyglucosone (3-DG) in commonly-consumed products in a Western diet. We validated a UHPLC-MS/MS method to quantify MGO, GO, and 3-DG. We present a dietary dicarbonyl database of 223 foods and drinks. Total dicarbonyl concentrations were highest in dried fruit, Dutch spiced cake, and candy bars (>400 mg/kg). Total dicarbonyl concentrations were lowest in tea, dairy, light soft drinks, and rice (<10 mg/kg). The presented database of MGO, GO, and 3-DG opens the possibility to accurately estimate dietary exposure to these dicarbonyls, and explore their physiological impact on human health.


Assuntos
Bebidas/análise , Bases de Dados Factuais , Análise de Alimentos/métodos , Compostos Orgânicos/análise , Manipulação de Alimentos , Humanos , Compostos Orgânicos/química , Espectrometria de Massas em Tandem
19.
Chemosphere ; 263: 128065, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33297070

RESUMO

Dielectric barrier discharge (DBD) plasma has been recently used for removal of synthetic organic compounds (SOCs) from aqueous environments. The removal of SOCs by alone DBD is significantly limited by its high electricity needs and inefficient mineralization, which affects the further application of DBD for SOCs. The combined application of DBD with other technologies and the addition of a supplementary substance for energy-saving were proposed to resolve these problems. The addition of catalysts is considered to be a promising and innovative approach to increase the energy yield of DBD, improve the environment friendly of DBD, develop the variety of goal SOCs, and improve the removal efficiency of DBD system. Despite the increasing use of the coupling form of DBD and catalysts, as catalytic dielectric barrier discharge (CDBD), but it still requires a comprehensive review to summarize the last studies and highlight the future perspectives in this area. Therefore, this work is the first literature review aimed to critically assess the latest developments of catalysts coupling with DBD employed in aqueous environments. Moreover, performance evaluation, energy yield, toxicity, eco-friendly, and future perspectives of the CDBD systems for SOCs removal were discussed and overviewed. The results showed that the coupling of catalysts with DBD presents synergistic effects and had excellent removal performance for aqueous SOCs. Overall, it can be concluded that the essential principles of environmental and economic sustainability have been addressed for the removal of persistent pollutants from aqueous environments in the CDBD systems.


Assuntos
Poluentes Químicos da Água , Catálise , Compostos Orgânicos , Plasma/química , Tecnologia , Poluentes Químicos da Água/análise
20.
Food Chem ; 334: 127585, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32711275

RESUMO

Glycerol monosterate (GMS) and stearic acid (SA) share a similar carbon chain structure while SA has a carboxyl head group and GMS has two free hydroxyl groups. The current research focuses on the relationship between GMS and SA chemical structure, nano and mesoscale crystal structure, and the oleogel macroscopic characteristics. Molecular analysis revealed the formation of different types of hydrogen bonds, which disappear upon temperature increase at different temperatures. Nano-structural analysis exhibited tight and ordered lamellar structures for SA compared with loosely packed short lamellar structures in GMS oleogel, presumably due to its larger hydrophilic head group. Microstructure imaging revealed ordered anisotropically orientated needle-like crystals in SA and isotopically ordered braid-like crystals in GMS oleogels. Mechanical analysis revealed that gel strength is enhanced when crystal structure is isotropically oriented, similar behavior seen is composite materials, where the structuring agent crystals behave like a reinforcing agent within the oil matrix.


Assuntos
Ácidos Esteáricos/química , Ligação de Hidrogênio , Nanoestruturas/química , Compostos Orgânicos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Termogravimetria , Difração de Raios X
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