Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 11.389
Filtrar
1.
Food Chem ; 303: 125390, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31450177

RESUMO

Cheddar cheese predicted to develop into different quality classes has been evaluated by time domain Nuclear Magnetic Resonance, Thermogravimetric analysis and quantitative sensory analysis. The water and fat proton signals in the transverse relaxation decay curves have been deconvoluted. Proton transverse relaxation values for both the water and fat fractions decrease and the relative %age of the proton peak area, predominantly from the fat increases over a 450-day ripening period. The thermodynamic free water percentage increases during maturation. Water and fat attributes can distinguish between Cheddar cheese batches after 56 days. Cheese batches which have lower transverse relaxation values for the water and fat proton fractions and a higher relative %age of the proton peak area predominantly from fat at 56 days, mature after 270 days to be more yellow, rubbery and smooth, have a less sour and lingering aftertaste and are also harder to form into a cheese ball.


Assuntos
Queijo/análise , Gorduras/análise , Manipulação de Alimentos , Água/análise , Espectroscopia de Ressonância Magnética , Paladar , Tempo
2.
Food Chem ; 302: 125338, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31434027

RESUMO

This study was designed to evaluate the baking performances of 25 edible dry bean (Phaseolus vulgaris L.) varieties and to investigate correlations among cookie features and rapid test indices (i.e., water and lactic acid retention capacities, oil binding capacity and Rapid Visco Analyzer indices). Two bean powder particle sizes (≤0.5 mm, ≤1.0 mm) were investigated. Cookies were evaluated in terms of nutritional, geometrical and textural properties. Bean powders doubled the amount of cookie protein and increased cookie resistant starch content. Baking potential varied according to bean genotype and powder particle size: coarse powders resulted in larger (+26%) and thinner (-19%) cookies characterized by easier breaking texture (fracture strengths of 41-157 vs. 48-226 kPa for fine powders). Water retention and oil binding capacities and pasting properties significantly (p < 0.05) correlated with cookie features. In conclusion, these accumulated findings can be used in designing value-added traditional and gluten-free cookies.


Assuntos
Phaseolus/química , Pós/química , Culinária , Dieta Livre de Glúten , Farinha , Ácido Láctico/análise , Ácido Láctico/química , Valor Nutritivo , Tamanho da Partícula , Amido/análise , Água/análise , Água/química
3.
Nature ; 575(7781): 169-174, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31666696

RESUMO

Two dry surfaces can instantly adhere upon contact with each other through intermolecular forces such as hydrogen bonds, electrostatic interactions and van der Waals interactions1,2. However, such instant adhesion is challenging when wet surfaces such as body tissues are involved, because water separates the molecules of the two surfaces, preventing interactions3,4. Although tissue adhesives have potential advantages over suturing or stapling5,6, existing liquid or hydrogel tissue adhesives suffer from several limitations: weak bonding, low biological compatibility, poor mechanical match with tissues, and slow adhesion formation5-13. Here we propose an alternative tissue adhesive in the form of a dry double-sided tape (DST) made from a combination of a biopolymer (gelatin or chitosan) and crosslinked poly(acrylic acid) grafted with N-hydrosuccinimide ester. The adhesion mechanism of this DST relies on the removal of interfacial water from the tissue surface, resulting in fast temporary crosslinking to the surface. Subsequent covalent crosslinking with amine groups on the tissue surface further improves the adhesion stability and strength of the DST. In vitro mouse, in vivo rat and ex vivo porcine models show that the DST can achieve strong adhesion between diverse wet dynamic tissues and engineering solids within five seconds. The DST may be useful as a tissue adhesive and sealant, and in adhering wearable and implantable devices to wet tissues.


Assuntos
Adesividade , Adesivos/química , Coração , Pulmão , Próteses e Implantes , Estômago , Molhabilidade , Resinas Acrílicas/química , Animais , Quitosana/química , Reagentes para Ligações Cruzadas/química , Dessecação , Gelatina/química , Coração/anatomia & histologia , Hidrogéis/química , Ligações de Hidrogênio , Pulmão/anatomia & histologia , Pulmão/química , Camundongos , Ratos , Eletricidade Estática , Estômago/anatomia & histologia , Estômago/química , Suínos , Fatores de Tempo , Água/análise , Água/química , Dispositivos Eletrônicos Vestíveis
4.
An Acad Bras Cienc ; 91(3): e20180578, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31596389

RESUMO

The aim of this study was to determine how often rural farmers in a watershed use no-tillage systems combined with crop rotation, contour farming and agricultural terraces. The study area was Paraná Watershed III (PB3) in the western region of Paraná State, and data from the 2006 Agricultural Census of the Brazilian Institute of Geography and Statistics were used. A frequency distribution analysis of farms as a function of the no-tillage (NT) area was conducted in combination with a cluster analysis of soil and water conservation practices (adoption of crop rotation, contour farming and agricultural terrace practices). The results showed that the farms in PB3 adopt adequate soil and water conservation practices, with 73% adopting NT combined with at least 2 other conservation practices; however, agricultural terracing was found to be the most neglected practice in the region. In addition, based on the soil and water conservation practices in the watershed, 5 groups of farms were identified, the worst of which, those located in the municipalities that mainly neglect conservation practices, live in areas with highly erodible soils.


Assuntos
Agricultura/métodos , Conservação dos Recursos Naturais/métodos , Produtos Agrícolas , Solo/química , Brasil , Água/análise , Abastecimento de Água
5.
Environ Monit Assess ; 191(10): 606, 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31485854

RESUMO

In this paper, 329 Landsat images combined with the Deeply Clear Water Extraction Index were applied to delineate boundaries of Hongjiannao Lake during 1986-2018. The net shoreline movement (NSM) and linear regression rate (LRR) achieved by Digital Shoreline Analysis System (DSAS) were employed to depict the distance and rate change of lake shorelines. Based on the waterline method and lake boundaries, the water levels were derived from ASTER GDEM V2. Water volume variations were evaluated using the combination of lake area and water level. The variations in Hongjiannao Lake can be grouped into three stages: (i) The lake area, water level, and volume variations slightly declined from 57.25 km2, 1211.15 m, and - 0.0220 km3 in 1986 to 56.36 km2, 1210.66 m, and - 0.036 km3 in 1997, respectively. The average degradation distance (NSM) and rate (LRR) of lake shorelines were 74.26 m and 3.48 m/a, respectively. Although these three aspects slightly decreased, they maintained a stable high level due to stability of natural factors. (ii) A rapid decrease in these three aspects during 1998-2015 was expressed by rates of - 1.15 km2/a (the total decrease was - 21.72 km2), - 0.18 m/a (the total decrease was - 3.45 m), and - 0.0068 km3/a (the total decrease was - 0.1419 km3), respectively. The average shrinkage distance (NSM) and rate (LRR) of lake boundaries were 1049.35 m and 55.00 m/a, respectively, and gradually intensifying human activities were the leading factor. (iii) These three aspects increased from 31.75 km2, 1207.03 m, and - 0.1852 km3 in 2016 to 36.19 km2, 1207.23 m, and - 0.1883 km3, respectively, in 2018. The average enlargement distance (NSM) and rate (LRR) of lake shorelines were 196.87 m and 67.85 m/a, respectively, mainly caused by closing of small mines, sluicing activities, and increase in annual precipitation.


Assuntos
Monitoramento Ambiental/métodos , Lagos/análise , Imagens de Satélites , Água/análise , Abastecimento de Água
6.
Environ Monit Assess ; 191(10): 639, 2019 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-31529378

RESUMO

Although indispensable, significant uncertainty still exists in the underlying processes of the formation, dynamics, and emission of greenhouse gases (GHGs), the critical elements needed for the accurate estimation of greenhouse gas fluxes in inland lakes and reservoirs. Seasonal changes in water thermal stratification and turbulence strongly influence the concentration and emission of dissolved GHGs in water columns. Here, we studied the stratification and overturn processes of water column in the subtropical Lianhe Reservoir during different seasons and determined the dynamics of dissolved CO2, CH4, and N2O in the reservoir. Observation of temperature and analysis of chlorofluorocarbons (CFCs) clearly suggested that stratification of water column occurred in summer, but not in winter. The results showed that while dissolved oxygen (DO) was high in the top 5-m layer (the upper epilimnion layer), it dropped considerably especially below 10 m, resulting in an increase in concentration of CO2 and CH4. The high concentrations of dissolved N2O and CH4 were related to the decomposition of organic matter in the hypolimnion layer under anaerobic conditions after stratification. In winter overturn period, vertical circulants of water not only homogenized the concentration of DO in the water column, but also potentially moved CO2, CH4, and N2O from the bottom to the surface of the reservoir. The estimated GHG flux from the reservoir was - 7.13 mmol m-2 day-1 in summer and 2.14 mmol m-2 day-1 in winter. There was the potential that CO2 fluxes from subtropical lakes and reservoirs are overestimated by traditional geochemical models.


Assuntos
Monitoramento Ambiental/métodos , Gases de Efeito Estufa/análise , Oxigênio/análise , Água/análise , Dióxido de Carbono/análise , Lagos/análise , Estações do Ano
7.
J Agric Food Chem ; 67(40): 11077-11088, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31525039

RESUMO

Cuticular wax accumulation in plants contributes to drought tolerance. Here, we compared the drought levels on two varieties with different genotypes in turnip (Brassica rapa var. rapa) and found that the drought tolerance was higher in the waxy KTRG-B48a than in the wax-free KTRG-B48b. A combination of PacBio and Illumina sequencing analyses revealed that differential transcripts were mainly enriched in the wax synthesis pathway, and a splice variant (BrrWSD1-X2) was identified in the waxy KTRG-B48a. BrrWSD1-X2 had a stronger ability to synthesize wax esters than BrrWSD1-X1 using heterologous expression in yeast (Saccharomyces cerevisiae) mutant H1246a. Then, we speculated that the T to C transversion of the third intron and the higher number of TA repeats in the third intron of BrrWSD1 DNA in the waxy KTRG-B48a may result in a lower efficiency of splicing recognition of the third intron, resulting in the emergence of BrrWSD1-X2 in waxy varieties.


Assuntos
Brassica rapa/fisiologia , Ésteres/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Ceras/metabolismo , Brassica rapa/genética , Secas , Processamento de RNA , Água/análise , Água/metabolismo
8.
Int J Food Microbiol ; 306: 108273, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31382055

RESUMO

Ochratoxin A (OTA) is a nephrotoxic mycotoxin naturally found in a wide range of food commodities throughout the world. Aspergillus carbonarius is the most important source of OTA in food commodities such as wine, grapes and dried vine fruits and is also responsible for the formation of OTA in coffee. The aim of this study was to determine the simultaneous effect of three culture media (Czapek Yeast Extract Broth (CYB); Synthetic Grape Juice Medium (SGM) and White grape juice (WGJ)) at three water activity (aw) levels (0.90; 0.95 and 0.98-0.99), and three incubation temperatures (15 °C, 25 °C and 35 °C) on the growth and OTA production by 16 strains of A. carbonarius. The strains were mainly isolated from grapes from areas with a Mediterranean climate. All the strains were confirmed for identity by sequencing of the calmodulin gene. The assay was performed in microtiter plates, determining the absorbance at 530 nm and the concentration of OTA after 1, 2, 4 and 10 days of incubation. No significant differences were observed in absorbance values between the strains. The highest absorbance values were recorded in CYB at 0.99 aw and at 0.95 aw after 10 days of incubation at 25 °C and 35 °C. None of the strains were able to grow at 0.90 aw and 15 °C in any culture media after 10 days of incubation. OTA concentration was statistically higher at 15 °C than at 25 °C or 35 °C. The highest significant OTA values were obtained at 0.98-0.99 aw and the best culture media for OTA production was CYB, followed by WGJ and SGM. While strains isolated from Mediterranean climate foods had a similar behavior despite being isolated from different geographical areas, OTA concentration produced by one Robusta coffee strain from Thailand was statistically higher at 25 °C than at 15 °C. This would suggest that the type of food matrices and consequently the adaptation of A. carbonarius strains to different climatic conditions would have a greater influence on the ecophysiology of the strains than only their geographical origin.


Assuntos
Aspergillus/crescimento & desenvolvimento , Aspergillus/metabolismo , Meios de Cultura/farmacologia , Micotoxinas/biossíntese , Ocratoxinas/biossíntese , Aspergillus/patogenicidade , Clima , Meio Ambiente , Microbiologia de Alimentos , Temperatura Ambiente , Tailândia , Vitis/microbiologia , Água/análise , Vinho/microbiologia
9.
Anal Bioanal Chem ; 411(26): 7039-7049, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31428817

RESUMO

Antibiotic compounds in natural waters are normally present at low concentrations. In this paper, an easy and highly sensitive screening method using graphene oxide-functionalized magnetic composites (GO@NH2@Fe3O4) combined with matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) was established for twelve quinolone antibiotics. GO@NH2@Fe3O4 composites were utilized as adsorbents for magnetic solid-phase extraction. This method combines the advantages of magnetic solid-phase extraction and MALDI-TOF MS, which allows for fast detection of quinolones at low concentrations. To improve absorption efficiency, the following parameters were individually optimized: sample acidity, extraction time, amount of adsorbent used, eluent used, and desorption time. Under the optimum conditions, the established method gave a low detection limit of 0.010 mg/L and allowed the high-throughput screening of twelve quinolone antibiotics (enoxacin, norfloxacin, ciprofloxacin, pefloxacin, fleroxacin, gatifloxacin, enrofloxacin, levofloxacin, sparfloxacin, danofloxacin, difloxacin, and lomefloxacin). The proposed method, having an easily prepared sorbent with a high affinity for quinolones and a convenient, high-throughput detection step, has been shown to have merit for the detection of antibiotics in water samples. Graphical abstract Schematic illustration of the (A) preparation of GO@NH2@Fe3O4 and (B) operating procedure for the MSPE and MALDI-TOF MS detection of QNs.


Assuntos
Antibacterianos/análise , Grafite/química , Quinolonas/análise , Extração em Fase Sólida/métodos , Poluentes Químicos da Água/análise , Antibacterianos/isolamento & purificação , Limite de Detecção , Imãs/química , Modelos Moleculares , Quinolonas/isolamento & purificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Água/análise , Poluentes Químicos da Água/isolamento & purificação
10.
Ecotoxicol Environ Saf ; 183: 109567, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31442802

RESUMO

Polycyclic aromatic hydrocarbons (PAHs) are universal organic pollutants in the agro ecosystems in China, therefore, it is important to understand the uptake and accumulation of PAHs in crops growing on PAHs contaminated soils for human health risk assessments. Water management is a common practice to maintain high grain yields during wheat production. However, the effects of soil water content on the accumulation and translocation of PAHs in wheat are still not clear. The main objectives of the present study were to investigate the effects of soil water content on the accumulation of three selected PAHs (Σ3PAHs, phenanthrene, anthracene and pyrene) in wheat during whole plant growth stage and on translocation or remobilization of Σ3PAHs from vegetative tissues to wheat grains. Winter wheat (Triticum aestivum cv. Xiaoyan22) were grown on Σ3PAHs spiked soils maintaining 80%, 60% or 40% water-holding capacity during the whole plant growth stage. Plant samplings were performed at jointing, anthesis or maturity stage, respectively. The present study showed that grain yield and biomass of the crop increased with soil water content increasing. Transpiration rate of wheat leaf under 80% and 60% water-holding capacity treatments was significantly (p < 0.05) higher than that under 40% water-holding capacity treatment at both anthesis and filling stage. Soil water content and plant growth stage had significant (p < 0.0001) effects on concentrations of phenanthrene, anthracene and pyrene in winter wheat. When exposed to 0, 15, 60, and 150 mg kg-1 Σ3PAHs in soils, Σ3PAHs concentrations in the grains under 60% water-holding capacity treatment were 46.6%, 69.9%, 89.5% and 81.7% of those under 80% water-holding capacity treatment, respectively. The highest concentrations of Σ3PAHs in the crop were recorded at anthesis stage. The distribution of PAHs in different tissues of wheat varied among different soil water treatments and plant growth stages. The present study indicated that optimizing soil water content during winter wheat production could apparently reduce concentrations of Σ3PAHs in grains via influence root uptake of Σ3PAHs and translocation of Σ3PAHs from stem or leaf into grain, suggesting the potential of water management to cope with PAHs contamination in crops growing on PAHs contaminated soils.


Assuntos
Antracenos/análise , Fenantrenos/análise , Pirenos/análise , Solo/química , Triticum/química , Água/análise , Antracenos/metabolismo , Transporte Biológico , Biomassa , China , Grão Comestível/química , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/metabolismo , Fenantrenos/metabolismo , Folhas de Planta/química , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Pirenos/metabolismo , Estações do Ano , Triticum/crescimento & desenvolvimento , Triticum/metabolismo , Água/metabolismo
11.
Anal Bioanal Chem ; 411(25): 6767-6775, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31420710

RESUMO

Nonylphenols (NP) are ubiquitous in the environment and show toxic effects and estrogenic activity. According to the corresponding framework directive in the field of water quality, isomers of NP (including 4-n-NP and branched 4-NP) are classified as priority hazardous substances and are regulated as a group of chain and ring isomers with a maximum acceptable concentration of 2 µg/L in inland and other surface waters. This study presents a new sensitive and innovative screening approach for estrogen active NP based on high-performance thin-layer chromatography. NP were focused in a single target zone on thin-layer plates by planar solid phase extraction (pSPE) and detected by a planar yeast estrogen screen (pYES) on the basis of their estrogenic activity. The mean limits of detection and quantitation were 14 and 26 ng per zone, respectively. After liquid-liquid extraction of water samples with dichloromethane, the mean recovery was close to 100% (relative standard deviation of 21% or less), and estrogen active NP were detectable down to 1 µg/L. Thus, pSPE-pYES provides both the detection and the quantitation of estrogenic NP in surface waters at the maximum acceptable concentration. Application of the approach on extracts of surface waters showed the use of pSPE-pYES for environmental samples, and no complex and time-consuming clean-up of the extracts was required. Estrogenic NP were not detectable in any of the investigated surface waters by means of the screening approach presented.


Assuntos
Disruptores Endócrinos/análise , Fenóis/análise , Poluentes Químicos da Água/análise , Cromatografia em Camada Delgada/métodos , Disruptores Endócrinos/efeitos adversos , Monitoramento Ambiental/métodos , Fenóis/efeitos adversos , Extração em Fase Sólida/métodos , Água/análise , Poluentes Químicos da Água/efeitos adversos , Leveduras/efeitos dos fármacos
12.
J Agric Food Chem ; 67(35): 9697-9704, 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31403787

RESUMO

In higher plants, seed size is an important parameter and agricultural trait in many aspects of evolutionary fitness. The loss of water-deficiency-induced crop yield is the largest among all natural hazards. Under water-deficient stress, the most prevalent response to terminal stress is to accelerate the early arrest of floral development and, thereby, to accelerate fruit/seed production, which consequently reduces seed size. This phenomenon is well-known, but its molecular mechanism is not well-reviewed and characterized. However, increasing evidence have indicated that water-deficient stress is always coordinated with three genetic signals (i.e., seed size regulators, initial seed size, and fruit number) that decide the final seed size. Here, our review presents new insights into the mechanism underlying cross-talk water-deficient stress signaling with three genetic signals controlling final seed size. These new insights may aid in preliminary screening, identifying novel genetic factors and future design strategies, or breeding to increase crop yield.


Assuntos
Sementes/citologia , Água/metabolismo , Secas , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Sementes/genética , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Estresse Fisiológico , Água/análise
13.
J Sci Food Agric ; 99(15): 6973-6980, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31414485

RESUMO

BACKGROUND: Plants activate defense mechanisms to cope with adverse environmental conditions, leading to the accumulation and / or depletion of general and specialized metabolites. In this study, a multiplatform untargeted metabolomics strategy was employed to evaluate metabolic changes in strawberry fruit of cv. Camarosa grown under osmotic stress conditions. Liquid chromatography-mass spectrometry (LC-MS/MS) and gas chromatography-mass spectrometry (GC-MS) data from strawberries grown under two water-deficit conditions, irrigated at 95% crop evapotranspiration (ETc) and 85% ETc, and one excess salt condition with a 80 mmol L-1 NaCl solution, were analyzed to determine treatment effects on fruit metabolism. RESULTS: Multivariate principal component analysis, orthogonal projections to latent structures - discriminant analysis (OPLS-DA), and univariate statistical analyses were applied to the data set. While multivariate analyses showed group separation by treatment, T-tests and fold change revealed 12 metabolites differentially accumulated in strawberries from different treatments - among them phenolic compounds, glycerophospholipids, phytosterols, carbohydrates, and an aromatic amino acid. CONCLUSION: Untargeted metabolomic analysis allowed for the annotation of compounds differentially accumulated in strawberry fruit from plants grown under osmotic stress and non-stressed plants. The metabolic disturbance in plants under stress involved metabolites associated with the inhibition of reactive oxygen species and cell-wall and membrane lipid biosynthesis, which might serve as osmotic stress biomarkers. © 2019 Society of Chemical Industry.


Assuntos
Fragaria/química , Frutas/metabolismo , Cromatografia Líquida , Fragaria/crescimento & desenvolvimento , Fragaria/metabolismo , Frutas/química , Frutas/crescimento & desenvolvimento , Cromatografia Gasosa-Espectrometria de Massas , Metabolômica , Pressão Osmótica , Cloreto de Sódio/análise , Cloreto de Sódio/metabolismo , Espectrometria de Massas em Tandem , Água/análise , Água/metabolismo
14.
Environ Pollut ; 254(Pt A): 113028, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31421575

RESUMO

Disinfection byproducts (DBPs) generated by ballast water treatment have become a concern worldwide because of their potential threat to the marine environment. Predicting the relative DBP concentrations after disinfection could enable better control of DBP formation. However, there is no appropriate method of evaluating DBP formation in a full-scale ballast water treatment system (BWTS). In this study, multiple regression models were developed for predicting the dibromochloromethane (DBCM) and bromoform (TBM) concentrations produced by an emergency BWTS using field experimental data from ballast water treatments conducted at Dalian Port, China. Six combinations of independent variables [including several water parameters and/or the total residual oxidant (TRO) concentration] were evaluated to construct mathematical prediction formulas based on a polynomial linear model and logarithmic regression model. Further, statistical analyses were performed to verify and determine the appropriate mathematical models for DBCM and TBM formation, which were ultimately validated using additional field experimental data. The polynomial linear model with four variables (temperature, salinity, chlorophyll, and TRO) and the logarithmic regression model with seven variables (temperature, salinity, dissolved oxygen, pH, turbidity, chlorophyll, and TRO) exhibited good reproducibility and could be used to predict the DBCM and TBM concentrations, respectively. The validation results indicated that the developed models could accurately predict DBP concentrations, with no significant statistical difference from the measured values. The results of this work could provide a theoretical basis and data reference for ballast water treatment control in engineering applications of emergency BWTSs.


Assuntos
Poluentes Químicos da Água/análise , Poluição da Água/estatística & dados numéricos , Purificação da Água/métodos , China , Desinfecção/métodos , Oxidantes , Oxirredução , Reprodutibilidade dos Testes , Salinidade , Navios , Trialometanos/análise , Água/análise
15.
Environ Pollut ; 254(Pt B): 113037, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31454567

RESUMO

Angola is one of the countries with a high rate of waterborne diseases, due to the scarcity and poor quality of water for human consumption. The watercourses are receptors of many effluents, mainly domestic sewage, due to a precarious or inexistent sanitation system and a small number of wastewater treatment plants. Therefore, this study aims: (i) to evaluate the water quality (physicochemical and microbiological parameters) of three Angolan rivers (Kwanza, Bengo and Dande) in locations where water is used as drinking water or abstracted for human consumption; (ii) to develop a new water quality index able to quantitatively express the water quality in those sites; and (iii) to assess the spatial distribution of water pollution through principal component analysis (PCA). Water quality assessment was performed by conducting four field surveys (campaigns I to IV); the first two campaigns took place in the dry season, while the last two ones took place in the rainy season. In the first two campaigns, the water quality was suitable to be treated for the production of drinking water, while in the last two campaigns, the water was unsuitable for that purpose (high levels of faecal coliforms were detected). The water quality index allowed to classify the water as generally excellent (campaigns I and II) and poor (campaigns III and IV). The rudimentary disinfection usually performed by individual water suppliers may improve the water quality, but it was not enough to achieve the parametric values required for human consumption in the rainy season (campaigns III and IV) except for Bengo sites. PCA identified sampling sites with the same water quality patterns, grouping into four groups (Kwanza sites) and two groups (Dande and Bengo sites). Therefore, the results of this study may support decision-makers as regards water supply management in the river stretches under study. The new developed Water Quality Index can support decision-makers in terms of water supply management, especially in countries with a high rate of waterborne diseases (e.g. Angola).


Assuntos
Água Potável/microbiologia , Monitoramento Ambiental/métodos , Poluentes Químicos da Água/análise , Angola , Água Potável/química , Fezes/química , Humanos , Chuva , Rios/química , Rios/microbiologia , Saneamento , Estações do Ano , Esgotos/análise , Águas Residuárias/análise , Água/análise , Microbiologia da Água , Poluição da Água/análise , Qualidade da Água , Doenças Transmitidas pela Água
16.
Nature ; 572(7767): 51-55, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31367029

RESUMO

The cooling of the Earth's climate through the effects of anthropogenic aerosols on clouds offsets an unknown fraction of greenhouse gas warming. An increase in the amount of water inside liquid-phase clouds induced by aerosols, through the suppression of rain formation, has been postulated to lead to substantial cooling, which would imply that the Earth's surface temperature is highly sensitive to anthropogenic forcing. Here we provide direct observational evidence that, instead of a strong increase, aerosols cause a relatively weak average decrease in the amount of water in liquid-phase clouds compared with unpolluted clouds. Measurements of polluted clouds downwind of various anthropogenic sources-such as oil refineries, smelters, coal-fired power plants, cities, wildfires and ships-reveal that aerosol-induced cloud-water increases, caused by suppressed rain formation, and decreases, caused by enhanced evaporation of cloud water, partially cancel each other out. We estimate that the observed decrease in cloud water offsets 23% of the global climate-cooling effect caused by aerosol-induced increases in the concentration of cloud droplets. These findings invalidate the hypothesis that increases in cloud water cause a substantial climate cooling effect and translate into reduced uncertainty in projections of future climate.


Assuntos
Aerossóis/análise , Aerossóis/química , Mudança Climática/estatística & dados numéricos , Atividades Humanas , Modelos Teóricos , Temperatura Ambiente , Água/análise , Água/química , Poluição do Ar/análise , Efeito Estufa/prevenção & controle , Efeito Estufa/estatística & dados numéricos , Chuva , Incerteza
17.
Food Chem ; 301: 125291, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31387031

RESUMO

Commission Regulation (EC) 543/2008 limits moisture and protein contents in poultry meat. However, this regulation leaves room for interpretation regarding sample homogenisation, potentially affecting comparability of laboratory results. Therefore, a proficiency test and sample homogenisation study were organised amongst 19 European National Reference Laboratories (NRL). In the proficiency test, three different pre-homogenised chicken samples (fillets, drumsticks and carcasses) were analysed. Only one NRL produced unsatisfactory results. In the homogenisation study, NRLs were supplied with uniform fillet, drumstick and carcass materials. Homogenisation was performed according to the NRLs in-house methods. Five NRLs did not return satisfactory results. As these NRLs produced satisfactory results in the proficiency test, their increase in z-scores was related to their homogenisation practices. Overall, scattering of individual results was higher for drumsticks compared to fillets and carcasses. Homogenisation practices for poultry meat introduced significant differences in moisture and protein results and standardisation is therefore advisable.


Assuntos
Análise de Alimentos/normas , Aves Domésticas , Proteínas/análise , Água/análise , Animais , Laboratórios , Carne/análise , Padrões de Referência
18.
Environ Monit Assess ; 191(9): 559, 2019 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-31402394

RESUMO

Various daily human activities can result in the release of pollutants of different chemical constituents and specific gravities into natural soils. Pollution of natural soils is a recurring occurrence in the environment and it contributes greatly to the alteration of soils properties. The results of an assessment of the effects of selected petroleum-derived and vegetable oils on soil physicochemical and hydraulic properties are presented in this work. Topsoil samples at a depth of 0-20 cm of the same textural class were collected from the order Lixisols and Nitisol within Ogun State, southwest Nigeria. Surface soil samples were collected and treated with petrol, diesel and palm oil at two different volumes (50 and 100 ml). Investigated soil properties include particle size distribution, soil pH, bulk density (BD), total porosity (TP), saturated hydraulic conductivity (Ksat), available water capacity (AWC), total carbon (TC), total nitrogen (TN), organic matter (OM) content, cation exchange capacity (CEC), potassium, sodium, and soil resistivity. Analysis of variance and Pearson's correlation were used to study the variations of the relationship of analyzed soil properties under different soil types and treatments. The regression analysis shows that all the generated models for predicting Ksat values under different soil treatments had R2 values ranging from 0.999 to 1.000. Results showed that treatment with either petroleum-derived or lipids has no effects on soil pH and textural class. Results further revealed that palm oil contamination at 50 ml recorded least values of Ksat in the two soil types. In all cases, BD and Ksat of the contaminated soils of the two sampling locations were reduced compared with their control values. Correlation coefficient showed expected strong negative correlation between TP and BD as well as between any two of organic parameters (TC, TN, and OM) and soil resistivity, TC, and TN at 1% level in both soil types. Two-way ANOVA showed that there were significant differences at 5% level between the two locations with respects to BD, TP, and CEC while significant differences in Ksat, pH, TC, TN, and OM occur between soils from the two locations under various treatments at 5% level.


Assuntos
Monitoramento Ambiental , Petróleo/análise , Poluentes do Solo/análise , Carbono/análise , Humanos , Nigéria , Nitrogênio/análise , Óleos Vegetais/análise , Solo/química , Água/análise
19.
Ying Yong Sheng Tai Xue Bao ; 30(8): 2607-2613, 2019 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-31418184

RESUMO

Using Granier-type thermal dissipation probes (TDP), we measured stem xylem sap flow of the natural dominant species Quercus liaotungensis and a reforestation species Robinia pseudoacacia from July to September in 2016 in the semiarid loess hilly region. Meteorological factors and soil water content were simultaneously monitored during the study period. Using cross-correlation analysis, time lag between diurnal patterns of sap flux density and vapor pressure deficit (VPD) was quantitatively estimated. Differences in the time lag between the two species and possible influence by different diameter classes and soil water contents were analyzed. The results showed that the diurnal courses of sap flux density were similar to those of meteorological factors, with daily peaks ear-lier than VPD. The peak of VPD lagged behind the sap flux densities of Q. liaotungensis and R. pseudoacacia 118.2 min and 39.5 min, respectively. The peak of PAR lagged behind the sap flux density of Q. liaotungensis 12.4 min, but was 68.5 min ahead of that for R. pseudoacacia. Time lag between sap flux density and VPD significantly varied between tree species and was affected by soil water content. Those during higher soil water content period were about 32.2 min and 68.2 min longer than those during the period with lower soil water content for the two species, respectively. There was no correlation between time lag and tree diameter classes. The time lag between VPD and sap flux density for R. pseudoacacia was about 21.4 min longer in smaller diameter trees than in larger trees, which was significantly different under the lower soil water content. Our results suggested that the time lag effect between VPD and sap flux densities in the two species reflected their sensitivities to driving factors of transpiration, and that higher soil water content was favorable to sap flux density reaching its peak early. The lower soil water content might lead to lower sensitivity of the trees to meteorological factors. R. pseudoacacia was more sensitive to changes of soil water content.


Assuntos
Transpiração Vegetal/fisiologia , Quercus/fisiologia , Robinia/fisiologia , China , Solo/química , Árvores , Água/análise
20.
J Agric Food Chem ; 67(33): 9399-9410, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31304753

RESUMO

This study investigated the feasibility of using hyperspectral imaging (HSI) to characterize the diffusion of acid and water within food structures during gastric digestion. Two different sweet potatoes (steamed and fried) and egg white gel (pH5 and pH9 EWGs) structures were exposed to in vitro gastric digestion before scanning by HSI. Afterward, the moisture or acid present in the digested sample was analyzed for calibration purposes. Calibration models were subsequently built using partial least-squares (PLS). The PLS models indicated that the full-wavelength spectral range (550-1700 nm) had a good ability to predict the spatial distribution of acid (Rcal2 > 0.82) and moisture (Rcal2 > 0.88). The spatiotemporal distributions of moisture and acid were mapped across the digested food, and they were shown to depend on the food composition and structure. The kinetic data revealed that the acid and moisture uptakes are governed by Fickian diffusion or by both diffusion and erosion-controlled mechanisms.


Assuntos
Ácidos/química , Clara de Ovo/química , Suco Gástrico/química , Ipomoea batatas/química , Ácidos/metabolismo , Animais , Galinhas , Difusão , Digestão , Suco Gástrico/metabolismo , Ipomoea batatas/metabolismo , Cinética , Água/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA