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1.
Nat Commun ; 11(1): 4547, 2020 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-32917880

RESUMO

Biodiversity loss can alter ecosystem functioning; however, it remains unclear how it alters decomposition-a critical component of biogeochemical cycles in the biosphere. Here, we provide a global-scale meta-analysis to quantify how changes in the diversity of organic matter derived from plants (i.e. litter) affect rates of decomposition. We find that the after-life effects of diversity were significant, and of substantial magnitude, in forests, grasslands, and wetlands. Changes in plant diversity could alter decomposition rates by as much as climate change is projected to alter them. Specifically, diversifying plant litter from mono- to mixed-species increases decomposition rate by 34.7% in forests worldwide, which is comparable in magnitude to the 13.6-26.4% increase in decomposition rates that is projected to occur over the next 50 years in response to climate warming. Thus, biodiversity changes cannot be solely viewed as a response to human influence, such as climate change, but could also be a non-negligible driver of future changes in biogeochemical cycles and climate feedbacks on Earth.


Assuntos
Biodiversidade , Aquecimento Global , Compostos Orgânicos/química , Plantas/química , Biodegradação Ambiental , Biomassa , Florestas , Pradaria , Áreas Alagadas
2.
Ecotoxicol Environ Saf ; 203: 110946, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888619

RESUMO

Zebrafish embryos are highly sensitive to toxicant exposure and have been used to evaluate the potential eco-toxicity caused by organic pollutants in the aquatic environment. This study was to develop four quantitative structure-activity relationship (QSAR) models based on norm descriptors for acute toxicity of different exposure times toward zebrafish embryo of organic compounds with various structures. Norm descriptors were obtained by calculating the norm index of the atomic distribution matrix, which was composed of atomic spatial distribution and atomic properties. These norm index-based QSAR models presented satisfactory results with R2 of 0.8549, 0.9162, 0.8335 and 0.8119 for 48, 96, 120 and 132 h, respectively. Validation results including cross validation, external validation, Y-randomized test and applicability domain analysis indicated that the proposed models were stable, robust and reliable. Accordingly, these norm descriptors might be effective in predicting the acute toxicity of various organics to zebrafish embryos, which might be useful for evaluating the potential hazards of organic pollutants to aquatic environment.


Assuntos
Embrião não Mamífero/efeitos dos fármacos , Compostos Orgânicos , Relação Quantitativa Estrutura-Atividade , Peixe-Zebra , Animais , Compostos Orgânicos/química , Compostos Orgânicos/toxicidade , Testes de Toxicidade Aguda
3.
J Environ Pathol Toxicol Oncol ; 39(3): 201-212, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32865912

RESUMO

Acute and chronic effects of ultraviolet radiation (UVR) on human health have long been a concern. It is well known that acute UVR causes epidermal hyperplasia, erythema, delayed tanning, pigment darkening, and free-radical formation. Apart from acute effects of UVR, its chronic effects involve immunosuppression, photoaging, exacerbation, photodermatoses, and photocarcinogenesis. To protect skin from harmful effects of UVR, UV filters were developed. But these may cause harmful effects in humans and on the environment; adverse effects of these chemicals have been evaluated for > 20 yr. Studies show that UV filters may lead to endocrine disruption, hepatotoxicity, mutagenicity, and systemic toxicity. Literature on environmental effects of UV filters suggests that they are bioaccumulative, pseudopersistent, and possibly toxic to aquatic ecosystems. The objective of this review is to summarize toxic effects and safety concerns of organic UV filters on human beings and the environment. We focus on UV filters' organic endocrine-disrupting effects by reviewing both in vivo and in vitro studies.


Assuntos
Disruptores Endócrinos/toxicidade , Compostos Orgânicos/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Reprodução/efeitos dos fármacos , Protetores Solares/toxicidade , Animais , Biotransformação , Disruptores Endócrinos/química , Disruptores Endócrinos/farmacocinética , Humanos , Estrutura Molecular , Compostos Orgânicos/química , Compostos Orgânicos/farmacocinética , Protetores Solares/química , Protetores Solares/farmacocinética
4.
Nat Commun ; 11(1): 3880, 2020 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-32759942

RESUMO

Geological sources of H2 and abiotic CH4 have had a critical role in the evolution of our planet and the development of life and sustainability of the deep subsurface biosphere. Yet the origins of these sources are largely unconstrained. Hydration of mantle rocks, or serpentinization, is widely recognized to produce H2 and favour the abiotic genesis of CH4 in shallow settings. However, deeper sources of H2 and abiotic CH4 are missing from current models, which mainly invoke more oxidized fluids at convergent margins. Here we combine data from exhumed subduction zone high-pressure rocks and thermodynamic modelling to show that deep serpentinization (40-80 km) generates significant amounts of H2 and abiotic CH4, as well as H2S and NH3. Our results suggest that subduction, worldwide, hosts large sources of deep H2 and abiotic CH4, potentially providing energy to the overlying subsurface biosphere in the forearc regions of convergent margins.


Assuntos
Ecossistema , Hidrogênio/química , Metano/química , Minerais/química , Compostos Orgânicos/química , Termodinâmica , Amônia/química , Fenômenos Químicos , Fenômenos Geológicos , Sulfeto de Hidrogênio/química , Fenômenos Mecânicos , Fenômenos de Química Orgânica , Alcaloides de Triptamina e Secologanina/química , Erupções Vulcânicas
5.
J Chromatogr A ; 1625: 461277, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709329

RESUMO

The influence of impregnation the chromatographic plate adsorbent layer, silica, with hen's egg white albumin (OVA) or bovine serum albumin (BSA) on the retention of some popular medicines (paracetamol, aminophenazone, theophylline, caffeine, acetanilide, ciprofloxacin, tramadol, acetylsalicylic acid, acebutolol) is investigated. The effect of composition and buffer pH of the mobile phase on solute separation selectivity is also studied. The chromatographic systems with and without above mentioned albumins and their influence on investigated drug retention are compared. In general, it has been turned out that retention of tested medicines in systems with the sorbent impregnated with albumin significantly increase relative to those with non-impregnated.


Assuntos
Cromatografia em Camada Delgada/métodos , Clara de Ovo/química , Preparações Farmacêuticas/análise , Soroalbumina Bovina/química , Sílica Gel/química , Adsorção , Animais , Bovinos , Galinhas , Feminino , Concentração de Íons de Hidrogênio , Metanol/química , Compostos Orgânicos/química , Solventes/química , Espectroscopia de Infravermelho com Transformada de Fourier , Tolueno/química
6.
J Chromatogr A ; 1625: 461280, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709331

RESUMO

Polysaccharide-based chiral stationary phases (CSPs) are outstandingly suitable to play a key role in chiral HPLC method selection strategies, since they provide high success rates. One reason for this ability is that they adopt a diversity of higher order structures in various eluents, resulting in versatile chiral environments. A potential to extend this versatility further was expected and examined in the present study, based on the recently discovered hysteretic behavior of a widely used chiral selector (CS), amylose tris(3,5-dimethylphenylcarbamate). The hindered transitions of its structure, which are behind the history dependence of its separation ability, were used as a tool to identify distinct states of the chiral selector in order to exploit an extended selectivity space. The identification was carried out using a single diagnostic compound, as opposed to the common approach where testing a library of compounds is required. Eluent mixtures consisting of 2-propanol and either methanol or ethanol were scrutinized in terms of stability and robustness of the observed retentions. The solvent mixtures that were eligible for practical application in these respects were used to construct a screening sequence, including identical compositions combined with different column pretreatment. The gain achievable by using the proposed sequence was then evaluated using 15 enantiomer pairs with focus on resolution, enantiomer elution order and chemoselectivity.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Compostos Orgânicos/química , 2-Propanol/química , Amilose/análogos & derivados , Amilose/química , Etanol/química , Indanos/química , Metanol/química , Oxidiazóis/química , Fenilcarbamatos/química , Solventes/química , Estereoisomerismo , Estilbenos/química
7.
SAR QSAR Environ Res ; 31(8): 585-596, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32613864

RESUMO

The n-octanol/buffer solution distribution coefficient (or n-octanol/water partition coefficient) is of critical importance for measuring lipophilicity of drug candidates. After 4885 molecular descriptor generation, 15 molecular descriptors were selected to develop quantitative structure-property relationship (QSPR) models for distribution coefficients at pH 7.4 (log D 7.4) of a large data set consisting of 1043 organic compounds, which was divided into a training set (600 compounds) and a test set (443 compounds). Support vector machine (SVM) based on genetic algorithm was used to develop a model for log D 7.4 that has coefficient of determination r 2 of 0.919 for the training set and 0.893 for the test set. The results suggest that the SVM model is accurate in predicting log D 7.4.


Assuntos
Compostos Orgânicos/química , Relação Quantitativa Estrutura-Atividade , Máquina de Vetores de Suporte
8.
Ecotoxicol Environ Saf ; 203: 110983, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32678760

RESUMO

Chelating agents have been considered as an important phytoremediation strategy to enhance heavy metal extraction from contaminated soil. A pot experiment was conducted to explore the effects of low molecular weight organic acids (LMWOAs) on the phytoremediation efficiency of copper (Cu) by castor bean, and soil enzyme activities. Results indicated that the addition of all the three kinds of LMWOAs (citric, tartaric, oxalic acids) did not decrease the biomass of castor bean, despite the fact they reduced the concentration of chlorophyll-a in leaves compared to the control. The Cu concentrations in the roots and shoots significantly increased by 6-106% and 5-148%, respectively, in the LMWOAs treatments so that the total accumulation of Cu by whole plants in all the LMWOAs treatments increased by 21-189% in comparison with the control. The values of the translocation factor (TF) and bio-concentration factor (BCF) of Cu in castor bean also rose following the addition of LMWOAs, indicating that the LMWOAs enhanced the uptake and transportation of Cu. Moreover, the application of LMWOAs did not significantly change the soil pH but significantly increased the activity of soil enzymes (urease, catalase, and alkaline phosphatase). The addition of exogenous LMWOAs increased the available Cu significantly in the soil, thus promoted the phytoextraction efficiency of Cu by castor bean. These results will provide some new insights into the practical use of LMWOAs for the phytoremediation of heavy-metal-contaminated soil employing castor bean.


Assuntos
Bioacumulação , Semente de Rícino/metabolismo , Quelantes/química , Cobre/metabolismo , Compostos Orgânicos/química , Poluentes do Solo/metabolismo , Solo/química , Ácidos/administração & dosagem , Ácidos/química , Biodegradação Ambiental , Semente de Rícino/efeitos dos fármacos , Quelantes/administração & dosagem , Peso Molecular , Compostos Orgânicos/administração & dosagem
9.
Nat Commun ; 11(1): 3743, 2020 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-32719350

RESUMO

Ions are ubiquitous biological regulators playing a key role for vital processes in animals and plants. The combined detection of ion concentration and real-time monitoring of small variations with respect to the resting conditions is a multiscale functionality providing important information on health states. This multiscale functionality is still an open challenge for current ion sensing approaches. Here we show multiscale real-time and high-sensitivity ion detection with complementary organic electrochemical transistors amplifiers. The ion-sensing amplifier integrates in the same device both selective ion-to-electron transduction and local signal amplification demonstrating a sensitivity larger than 2300 mV V-1 dec-1, which overcomes the fundamental limit. It provides both ion detection over a range of five orders of magnitude and real-time monitoring of variations two orders of magnitude lower than the detected concentration, viz. multiscale ion detection. The approach is generally applicable to several transistor technologies and opens opportunities for multifunctional enhanced bioelectronics.


Assuntos
Amplificadores Eletrônicos , Sistemas Computacionais , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Íons/análise , Compostos Orgânicos/química , Transistores Eletrônicos , Eletricidade , Humanos , Íons/sangue , Potássio/análise
10.
Nature ; 583(7815): 253-258, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32612230

RESUMO

The cortex organizes sensory information to enable discrimination and generalization1-4. As systematic representations of chemical odour space have not yet been described in the olfactory cortex, it remains unclear how odour relationships are encoded to place chemically distinct but similar odours, such as lemon and orange, into perceptual categories, such as citrus5-7. Here, by combining chemoinformatics and multiphoton imaging in the mouse, we show that both the piriform cortex and its sensory inputs from the olfactory bulb represent chemical odour relationships through correlated patterns of activity. However, cortical odour codes differ from those in the bulb: cortex more strongly clusters together representations for related odours, selectively rewrites pairwise odour relationships, and better matches odour perception. The bulb-to-cortex transformation depends on the associative network originating within the piriform cortex, and can be reshaped by passive odour experience. Thus, cortex actively builds a structured representation of chemical odour space that highlights odour relationships; this representation is similar across individuals but remains plastic, suggesting a means through which the olfactory system can assign related odour cues to common and yet personalized percepts.


Assuntos
Odorantes/análise , Córtex Olfatório/anatomia & histologia , Córtex Olfatório/fisiologia , Condutos Olfatórios , Compostos Orgânicos/análise , Compostos Orgânicos/química , Animais , Masculino , Camundongos , Bulbo Olfatório/citologia , Bulbo Olfatório/fisiologia , Córtex Olfatório/citologia , Percepção Olfatória/fisiologia , Olfato
11.
BMC Bioinformatics ; 21(1): 309, 2020 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-32664863

RESUMO

BACKGROUND: Despite continued efforts using chemical similarity methods in virtual screening, currently developed approaches suffer from time-consuming multistep procedures and low success rates. We recently developed a machine learning-based chemical binding similarity model considering common structural features from molecules binding to the same, or evolutionarily related targets. The chemical binding similarity measures the resemblance of chemical compounds in terms of binding site similarity to better describe functional similarities that arise from target binding. In this study, we have shown how the chemical binding similarity could be used in virtual screening together with the conventional structure-based methods. RESULTS: The chemical binding similarity, receptor-based pharmacophore, chemical structure similarity, and molecular docking methods were evaluated to identify an effective virtual screening procedure for desired target proteins. When we tested the chemical binding similarity method with test sets of 51 kinases, it outperformed the traditional structural similarity-based methods as well as structure-based methods, such as molecular docking and receptor-based pharmacophore modeling, in terms of finding active compounds. We further validated the results by performing virtual screening (using the chemical binding similarity and receptor-based pharmacophore methods) against a completely blind dataset for mitogen-activated protein kinase kinase 1 (MEK1), ephrin type-B receptor 4 (EPHB4) and wee1-like protein kinase (WEE1). The in vitro kinase binding assay confirmed that 6 out of 13 (46.2%) for MEK1 and 2 out of 12 (16.7%) for EPHB4 were newly identified only by the chemical binding similarity model. CONCLUSIONS: We report that the virtual screening results could further be improved by combining the chemical binding similarity model with 3D-QSAR pharmacophore and molecular docking models. Not only the new inhibitors are identified in this study, but also many of the identified molecules have low structural similarity scores against already reported inhibitors and that show the revelation of novel scaffolds.


Assuntos
Simulação de Acoplamento Molecular , Relação Quantitativa Estrutura-Atividade , Área Sob a Curva , Sítios de Ligação , Humanos , Aprendizado de Máquina , Compostos Orgânicos/química , Compostos Orgânicos/metabolismo , Preparações Farmacêuticas/química , Preparações Farmacêuticas/metabolismo , Ligação Proteica , Proteínas Quinases/química , Proteínas Quinases/metabolismo , Curva ROC
12.
Ecotoxicol Environ Saf ; 201: 110817, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32512417

RESUMO

Cellular exposure to xenobiotic human-made products will lead to oxidative stress that gives rise to DNA damage, as well as chemical or mechanical damage. Distinguishing the chemicals that will induce oxidative stress and predicting their toxicity is necessary. In the present study, 4270 compounds in the ARE-bla assay were investigated to predict active and inactive compounds by using simple algorithms, namely, recursive partitioning (RP) and binomial logistic regression, and to develop the quantitative structure-activity relationship (QSAR) models of chemicals that activate the ARE pathway to induce oxidative stress and exert toxic effects on cells. A decision tree based on scaffold-based fragments obtained through RP analysis showed the best identification accuracy. However, the overall identification accuracy of this model for active compounds was unsatisfactory due to limited fragments. Furthermore, a binomial logistic regression model was developed from 638 active compounds and 3632 inactive chemicals. The model with a cutoff of 0.15 could predict chemicals that were active or inactive with the prediction accuracy of 69.1%. Its area under the receiver operating characteristic (ROC) curve metric (AUROC) was 0.762, which indicated the acceptable predictive ability of this model. The parameters nBM (number of multiple bonds) and H% (percentage of H atom) played dominant roles in the prediction of the activity (inactive or active) of chemicals. A global QSAR model was developed to predict the toxicity of active chemicals. However, the model displayed an unsatisfactory result with R2 = 0.316 and R2ext = 0.090. Active chemicals were then classified on the basis of structure. A total of 79 compounds with carbon chains could be predicted with acceptable performance by using a QSAR model with six descriptors (R2 = 0.722, R2ext = 0.798, Q2Loo = 0.654, Q2Boot = 0.755, Q2ext = 0.721). The simple models established here contribute to efforts on identification compounds inducing oxidative stress and provide the scientific basis for risk assessment to organisms in the environment.


Assuntos
Compostos Orgânicos , Estresse Oxidativo/efeitos dos fármacos , Algoritmos , Elementos de Resposta Antioxidante/genética , Bioensaio , Bases de Dados Factuais , Genes Reporter , Humanos , Modelos Logísticos , Compostos Orgânicos/química , Compostos Orgânicos/toxicidade , Estresse Oxidativo/genética , Relação Quantitativa Estrutura-Atividade , beta-Lactamases/genética
13.
Chemosphere ; 258: 127338, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32544813

RESUMO

This study aimed to explore the catalytic effect of co-dissolved organic compounds on the tetracycline degradation by Fenton process both in the acidic and neutral environment. The experiments were carried out at [Fe2+]/[H2O2] of 50 µM/50 µM and 50 µM/100 µM. The humic acid, citrate and α-cyclodextrin were selected as the co-dissolved organic compounds. The best removal efficiency of 71% was observed at [Fe2+]/[H2O2] of 50 µM/100 µM without the presence of co-dissolved organic compounds. In the presence of co-dissolved organic compounds, the competition effect occurred and tetracycline removal efficiency was reduced to different extents depending on the H2O2 concentrations and chemical properties of the co-dissolved organic substances. The mechanistic exploration confirmed that the complex-forming interactions among Fe2+, tetracycline and organic co-dissolved molecules kept the catalytic ferrous/ferric redox cycle operating to generate hydroxyl radicals for tetracycline degradation at neutral condition, and this phenomenon was more obvious when the H2O2 concentration was higher. Complex formation also contributed to the overall tetracycline removal in addition to oxidation reactions. By comparing to the mass spectra of citrate, the α-cyclodextrin having a larger molecular structure might react with hydroxyl radicals at a higher probability, resulting in an apparent difference in degradation efficiency despite of the equality of their existing amount in the beginning of the experiment.


Assuntos
Recuperação e Remediação Ambiental/métodos , Peróxido de Hidrogênio/química , Compostos Orgânicos/química , Poluentes Químicos da Água/química , Catálise , Substâncias Húmicas , Ferro/química , Oxirredução , Tetraciclina/química , Poluentes Químicos da Água/análise
14.
Food Chem ; 328: 127123, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32480261

RESUMO

Protein- and lipid oxidation were investigated in whey protein based oleogels with varying water addition. Lipid oxidation was low (~30 mmol O2/kg lipid hydroperoxides after 6 weeks) in gels with < 0.23% water and a high (>1,000 mmol O2/kg lipid hydroperoxides after 4 weeks) in gels with > 2.4% water addition. In systems with > 2.4% water addition fluorescence (excitation 325 nm / emission 410 nm) as indicator of tyrosine oxidation and carbonyl content significantly increased and remained at low levels in oleogels with < 0.23% water addition. Primary amines as indicator for protein backbone breakage increased in early stages of oxidation in high water oleogels and decreased after 28 days. Degradation has been suggested to occur through interactions with reactive secondary lipid oxidation products and was confirmed by spiking experiments using respective compounds. The results suggest that secondary lipid oxidation markers are masked dependent on water addition in the presence of proteins.


Assuntos
Lipídeos/química , Água/química , Proteínas do Soro do Leite/química , Aminas/química , Géis/química , Compostos Orgânicos/química , Oxirredução
15.
Arch Biochem Biophys ; 689: 108435, 2020 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-32485153

RESUMO

Actinoporins are a family of pore-forming toxins produced by sea anemones as part of their venomous cocktail. These proteins remain soluble and stably folded in aqueous solution, but when interacting with sphingomyelin-containing lipid membranes, they become integral oligomeric membrane structures that form a pore permeable to cations, which leads to cell death by osmotic shock. Actinoporins appear as multigenic families within the genome of sea anemones: several genes encoding very similar actinoporins are detected within the same species. The Caribbean Sea anemone Stichodactyla helianthus produces three actinoporins (sticholysins I, II and III; StnI, StnII and StnIII) that differ in their toxic potency. For example, StnII is about four-fold more effective than StnI against sheep erythrocytes in causing hemolysis, and both show synergy. However, StnIII, recently discovered in the S. helianthus transcriptome, has not been characterized so far. Here we describe StnIII's spectroscopic and functional properties and show its potential to interact with the other Stns. StnIII seems to maintain the well-preserved fold of all actinoporins, characterized by a high content of ß-sheet, but it is significantly less thermostable. Its functional characterization shows that the critical concentration needed to form active pores is higher than for either StnI or StnII, suggesting differences in behavior when oligomerizing on membrane surfaces. Our results show that StnIII is an interesting and unexpected piece in the puzzle of how this Caribbean Sea anemone species modulates its venomous activity.


Assuntos
Venenos de Cnidários/química , Proteínas Citotóxicas Formadoras de Poros/química , Anêmonas-do-Mar/química , Sequência de Aminoácidos , Animais , Venenos de Cnidários/metabolismo , Hemólise/efeitos dos fármacos , Modelos Moleculares , Compostos Orgânicos/química , Compostos Orgânicos/metabolismo , Proteínas Citotóxicas Formadoras de Poros/metabolismo , Anêmonas-do-Mar/metabolismo , Alinhamento de Sequência , Ovinos
16.
Proc Natl Acad Sci U S A ; 117(27): 15473-15481, 2020 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-32571948

RESUMO

The development of sustainable methods for the degradation of pollutants in water is an ongoing critical challenge. Anthropogenic organic micropollutants such as pharmaceuticals, present in our water supplies in trace quantities, are currently not remediated by conventional treatment processes. Here, we report an initial demonstration of the oxidative degradation of organic micropollutants using specially designed nanoparticles and visible-wavelength sunlight. Gold "Janus" nanorods (Au JNRs), partially coated with silica to enhance their colloidal stability in aqueous solutions while also maintaining a partially uncoated Au surface to facilitate photocatalysis, were synthesized. Au JNRs were dispersed in an aqueous solution containing peroxydisulfate (PDS), where oxidative degradation of both simulant and actual organic micropollutants was observed. Photothermal heating, light-induced hot electron-driven charge transfer, and direct electron shuttling under dark conditions all contribute to the observed oxidation chemistry. This work not only provides an ideal platform for studying plasmonic photochemistry in aqueous medium but also opens the door for nanoengineered, solar-based methods to remediate recalcitrant micropollutants in water supplies.


Assuntos
Nanopartículas Metálicas/efeitos da radiação , Fotólise/efeitos da radiação , Luz Solar , Poluentes Químicos da Água/química , Poluição Química da Água/prevenção & controle , Ouro/química , Ouro/efeitos da radiação , Nanopartículas Metálicas/química , Nanotecnologia/métodos , Nanotubos/química , Nanotubos/efeitos da radiação , Compostos Orgânicos/química , Compostos Orgânicos/toxicidade , Oxirredução/efeitos da radiação , Dióxido de Silício/química , Dióxido de Silício/efeitos da radiação , Água/química , Poluentes Químicos da Água/toxicidade
17.
J Chromatogr A ; 1624: 461240, 2020 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-32540078

RESUMO

In this work, the use of different solvents and temperatures was explored, aiming to evaluate their influence on the enantioseparation of pesticides by HPLC in polar-organic conditions, employing a column containing immobilized amylose tris(3-chloro-5-methylphenyl-carbamate). The chiral separation of seventeen different pesticides widely used as herbicides, fungicides, insecticides and precursors were studied. The mobile phases included methanol, ethanol, iso-propanol, n-propanol and acetonitrile; either pure or containing additives such as diethylamine, trifluoroacetic acid, formic acid, acetic acid or mixtures thereof. We studied the influence of these eluents on chiral separation of those pesticides in terms of retention factor, enantioselectivity, enantioresolution and peak symmetry. Regarding temperature influence, evaluated within the range 5 - 40 °C, nearly all the compounds decreased their retention and selectivity factors with the increase in temperature, although the effect was dependent on the mobile phase solvent. Moreover, estimation of thermodynamic parameters was performed based on linear van´t Hoff plots.


Assuntos
Amilose/análogos & derivados , Compostos Orgânicos/química , Praguicidas/química , Praguicidas/isolamento & purificação , Fenilcarbamatos/química , Temperatura , Amilose/química , Cromatografia Líquida de Alta Pressão , Padrões de Referência , Solventes/química , Estereoisomerismo
18.
Ecotoxicol Environ Saf ; 201: 110827, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32535366

RESUMO

Numerous experimental and epidemiological studies have demonstrated that exposure to PM2.5 may result in pathogenesis of several major cardiovascular diseases (CVDs), which can be attributed to the combined adverse effects induced by the complicated components of PM2.5. Organic materials, which are major components of PM2.5, contain thousands of chemicals, and most of them are environmental hazards. However, the contamination profile and contribution to overall toxicity of PM2.5-bound organic components (OCs) have not been thoroughly evaluated yet. Herein, we aim to provide an overview of the literature on PM2.5-bound hydrophobic OCs, with an emphasis on the chemical identity and reported impairments on the cardiovascular system, including the potential exposure routes and mechanisms. We first provide an update on the worldwide mass concentration and composition data of PM2.5, and then, review the contamination profile of PM2.5-bound hydrophobic OCs, including constitution, concentration, distribution, formation, source, and identification. In particular, the link between exposure to PM2.5-bound hydrophobic OCs and CVDs and its possible underlying mechanisms are discussed to evaluate the possible risks of PM2.5-bound hydrophobic OCs on the cardiovascular system and to provide suggestions for future studies.


Assuntos
Poluentes Atmosféricos/toxicidade , Doenças Cardiovasculares/induzido quimicamente , Sistema Cardiovascular/efeitos dos fármacos , Monitoramento Ambiental/métodos , Compostos Orgânicos/toxicidade , Material Particulado/toxicidade , Poluentes Atmosféricos/química , Humanos , Interações Hidrofóbicas e Hidrofílicas , Compostos Orgânicos/química , Material Particulado/química
19.
Ecotoxicol Environ Saf ; 202: 110891, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32593097

RESUMO

Organophosphate ester contaminants, including organophosphate pesticides (OPPs) and organophosphate flame retardants (OPFRs) are ubiquitous in surface water and pose a significant risk to aquatic organisms, thus it is important to develop effective methods for long-term monitoring of these emerging compounds. Polar organic chemical integrative sampler (POCIS) has become a promising monitoring tool for waterborne contaminants, yet recent studies found that the commonly used polyethersulfone (PES) membrane strongly sorbed some moderately hydrophobic compounds, resulting in long lag-phase for chemical accumulation in POCIS. In the present study, 0.45-µm nylon membranes was selected as POCIS diffusion-limiting membrane to design a new POCIS-Nylon configuration for analyzing moderately hydrophobic OPPs and OPFRs in water. The POCIS-Nylon had negligible lag-phase due to low sorption of OPPs and OPFRs to nylon membrane. Meanwhile, linear accumulation time and sensitivity for target contaminants using POCIS-Nylon retained similar to the traditional POCIS. Water velocity and chemical concentration had little impact on sampling rate (Rs), validating that the POCIS-Nylon was suitable for various water conditions. Finally, the occurrence of OPPs and OPFRs in urban waterways of Guangzhou, China was evaluated using the POCIS-Nylon with Rs values that were calibrated in the laboratory. The average concentration of OPPs was 4.97 ± 1.35 ng/L (range: 2.64 ± 1.28-6.54 ± 0.18 ng/L) and the average concentration of OPFRs was 400 ± 88 ng/L (range: 316 ± 24-615 ± 36 ng/L) across nine sampling sites. The present study provides a way to resolve the inherent challenge of accumulating hydrophobic substances by POCIS.


Assuntos
Monitoramento Ambiental/métodos , Nylons/química , Poluentes Químicos da Água/análise , Calibragem , China , Retardadores de Chama/análise , Interações Hidrofóbicas e Hidrofílicas , Compostos Orgânicos/química , Organofosfatos/análise , Polímeros , Sulfonas
20.
PLoS One ; 15(6): e0234115, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32544157

RESUMO

The variation of the HOMO-LUMO band gap is explored for varying packing arrangements of the 4mod BT-4TIC donor-acceptor molecule pair, by means of a high-throughput ab-initio random structure search of packing possibilities. 350 arrangements of the dimer have been relaxed from initial random dispositions, using non-local density-functional theory. We find that the electronic band gap varies within 0.3 eV, and that this magnitude, the binding energy, and the geometry are not significantly correlated. A clearly favoured structure is found with a binding energy of 1.75±0.07 eV, with all but three other arrangements displaying values of less than one third of this highest binding one, which involves the aliphatic chain of 4TIC.


Assuntos
Compostos Orgânicos/química , Energia Solar , Teoria da Densidade Funcional , Tiadiazóis/química , Tiofenos/química
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