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1.
Food Chem ; 336: 127717, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32763740

RESUMO

Continued industrialization and increasing environmental problems have highlighted the need to research new eco-friendly solvents, also known as deep eutectic solvents (DESs). To implement these solvents in industrial processes, the knowledge of their molecular organization and thermophysical properties must be enhanced. In this work, two DESs have been characterized: d-glucose:choline chloride:water (GCH) and d-glucose:citric acid:water (GCiH). NMR techniques were used to analyse both the supramolecular structure and the role of water and to calculate the diffusion coefficients. Moreover, seven thermophysical properties at several temperatures were evaluated. As a second aim, the solubility of quercetin was determined. NMR studies showed a stronger supramolecular structure of GCH and a high ratio of ß-glucose in both DESs. Based on the thermophysical results, the solvent with choline chloride had the most compact fluid structure. Finally, the solubility of quercetin in the DESs was higher than in water, especially for GCH.


Assuntos
Glucose/química , Solventes/química , Colina/química , Ácido Cítrico/química , Espectroscopia de Ressonância Magnética , Quercetina/química , Solubilidade , Temperatura , Termodinâmica , Água/química
2.
Sci Total Environ ; 751: 141663, 2021 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-32866831

RESUMO

Beyond the contact and respiratory transmission of the COVID-19 virus, it has recently been reported in the literature that humidity, temperature, and air pollution may be effective in spreading the virus. However, taking the measurements regionally suspects the accuracy or validity of the data. In this research, climate values (temperature, humidity, number of sunny days, wind intensity) of 81 provinces in Turkey were collected in March 2020. Also, the population, population density of the provinces, and average air pollution data were taken. The findings of the study showed that population density and wind were effective in spreading the virus and both factors explained for 94% of the variance in virus spreading. Air temperature, humidity, the number of sunny days, and air pollution did not affect the number of cases. Besides, population density mediated the effect of wind speed (9%) on the number of COVID-19 cases. The finding that COVID-19 virus, invisible in the air, spreads more in windy weather indicates that the virus in the air is one threatening factor for humans with the wind speed that increases air circulation.


Assuntos
Infecções por Coronavirus , Pandemias , Pneumonia Viral , Vento , Betacoronavirus , Cidades , Humanos , Umidade , Densidade Demográfica , Temperatura , Turquia/epidemiologia
3.
Food Chem ; 334: 127614, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32711282

RESUMO

Pectin polysaccharide is an important phytochemical with potential biomedical applications. It is commonly measured by time-consuming destructive chemical methods. This work demonstrates the feasibility of using visible and near-infrared hyperspectral imaging (HSI) techniques to rapidly measure pectin polysaccharides in intact mulberry fruits. Based on spatial information provided by HSI images, the representative spectrum of each whole mulberry was accurately extracted without background. The effects of storage temperature on two varieties of mulberries for model establishment were studied. The performances of two spectral ranges obtained by Si and InGaAs CCD detectors for pectin prediction were compared. The best predictions were obtained from dilute alkali soluble pectin and total soluble pectin in Dashi mulberry fruit stored at room temperature, with residual predictive deviation values of 2.317 and 1.935, respectively. Our results show that HSI is a promising alternative to the chemical method to rapidly and nondestructively measure the pectin content.


Assuntos
Análise de Alimentos/métodos , Frutas/química , Morus/química , Pectinas/análise , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Armazenamento de Alimentos , Processamento de Imagem Assistida por Computador , Modelos Biológicos , Pectinas/química , Temperatura
4.
Food Chem ; 335: 127673, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32745844

RESUMO

This research focused on the effect of temperature (25-75 °C), extraction time (40-120 min) and solvent/solid ratio (15-45 mL/g) and the enzyme assisted extraction on protein extraction efficiency from by-product of sugar beet. 3 different methods were applied in protein isolation and the highest protein yield (34.55%) was obtained by the isoelectric-ammonium sulfate precipitation method. At the optimized condition of temperature 54.25 °C, 81.35 min, and solvent/solid ratio of 27.65 mL/g, the protein yield was found 55.15%. The protein yield has reached 79.01% with an increase of 43.27% with the aid of the enzyme assisted extraction. The physicochemical properties were determined for revealing its potential use in food industry. It is promising that the isolated protein concentrates (SPC-IAP) show high protein content (69.08% d.b) as well as high solubility (98.71% at pH 7.5). SPC-IAP's high brightness (L* = 79.55), low redness (a* = 0.33) and low yellowness (b* = 13.27) values are encouraging for food industry.


Assuntos
Beta vulgaris/química , Fracionamento Químico/métodos , Enzimas/química , Folhas de Planta/química , Proteínas de Plantas/isolamento & purificação , Enzimas/metabolismo , Indústria de Processamento de Alimentos/métodos , Concentração de Íons de Hidrogênio , Proteínas de Plantas/química , Pós/análise , Pós/química , Solubilidade , Solventes/química , Temperatura
5.
Food Chem ; 336: 127597, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32763732

RESUMO

In this study, bacterial cellulose nanocrystals (BCNCs) were obtained from bacterial cellulose nanofibers (BCNFs) by controlled hydrolysis of sulfuric and hydrochloric acids. The influence of hydrolysis temperature and acid type with the addition of the post-treatment step was studied. The obtained BCNCs were analyzed based on the structural characterization and the properties of the nanocrystals. The BCNCs crystallinity increased, and the size of nanocrystals decreased with increasing 10 °C hydrolysis temperature for both acid hydrolysis conditions. Hydrolysis conditions with neutralization post-treatment did not alter the thermal stability of nanocrystals, and BCNCs had high thermal stability like raw BCNFs. Elemental analysis results indicated that sulfur content (S %) was very low for sulfuric acid hydrolyzed samples, and X-ray results did not show any sulfate salt peaks. Thermal stable BCNCs with high crystallinity were successfully produced to meet the process requirements in various applications, especially in the food industry.


Assuntos
Celulose/química , Ácido Clorídrico/química , Nanopartículas/química , Ácidos Sulfúricos/química , Bactérias/metabolismo , Hidrólise , Temperatura
6.
Food Chem ; 336: 127625, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32771897

RESUMO

The solubility of carbon dioxide (CO2) in the moisture and protein components of cheese matrices and the influence of changing pH, salt and temperature levels remains unclear. In this study, model casein matrices were prepared, by renneting of micellar casein concentrate (MCC), with modulation of salt and pH levels by adding salt and glucono delta-lactone, respectively, to the MCC solutions prior to renneting. Different moisture-to-protein levels were achieved by freeze-drying, incubation of samples at different relative humidities, or by applying varying pressures during gel manufacture. The CO2 solubility of samples decreased linearly with both increasing temperature and salt-in-moisture content, whereas solubility of CO2 increased with increasing pH. A non-linear relationship was observed between CO2 solubility and the moisture-to-protein ratio of experimental samples. Overall, such knowledge may be applied to improve the quality and consistency of eye-type cheese, and in particular to avoid development of undesirable slits and cracks.


Assuntos
Dióxido de Carbono/química , Caseínas/química , Cloreto de Sódio/química , Água/química , Queijo/análise , Concentração de Íons de Hidrogênio , Pressão Parcial , Solubilidade , Temperatura
7.
Food Chem ; 336: 127707, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32763737

RESUMO

Anthocyanins (ACNs) are naturally derived colorants and antioxidants added to manufactured foods. ACNs were encapsulated in nanocomplexes with chitosan hydrochloride (CHC), carboxymethyl chitosan (CMC) and whey protein isolate (WPI). The ACN-loaded CHC/CMC-WPI nanocomplexes (ACN-CHC/CMC-WPI) showed a preferred particle size (332.20 nm) and zeta potential (+23.65 mV) and a high encapsulation efficiency (60.70%). ACN-CHC/CMC-WPI nanocomplexes exhibited a smooth spherical shape by transmission electron microscopy. Fourier transform infrared (FT-IR) and Raman spectroscopy confirmed interactions between the ACNs and the encapsulation materials (CHC/CMC-WPI). The nanocomplexes or the nanocomplexes incorporated into coffee beverage better protected ACNs at high temperature compared to the unencapsulated ACNs. In simulated gastrointestinal fluids, the ACNs in the ACN-CHC/CMC-WPI were more stable and more slower released over time. The nanocomplexes maintained high DPPH and hydroxyl free radical scavenging activities. This study indicated that CHC/CMC-WPI nanocomplexes can improve the thermal stability and slow the release of ACNs added to food products.


Assuntos
Antocianinas/farmacocinética , Quitosana/química , Café/química , Nanoestruturas/química , Proteínas do Soro do Leite/química , Antioxidantes/química , Quitosana/análogos & derivados , Digestão , Humanos , Microscopia Eletrônica de Transmissão , Tamanho da Partícula , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Temperatura
8.
Food Chem ; 336: 127716, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32768910

RESUMO

Jackfruit seed starch (JFSS) was modified by an improved extrusion cooking technology (IECT), and the supramolecular structure, molecular weight, debranched chain length distributions, relative crystallinity (Rc), and amylose content, were studied. During IECT, the α-1.4-glycosidic bond in amylopectin was broken, which led to decreased radius of gyration (Rg), number-average molar mass (Mn), weight-average molar mass (Mw), long chains and Rc. The medium and short chains and PI (Mw/Mn) increased, while the amylose content hardly changed. The crystalline structure of JFSS was converted from A-type to V-type. Increasing the temperature and screw speed during the treatment significantly increased the medium and short chains and Rg, while it decreased the long chains, amylose, Mn, Mw, PI, and Rc. However, the opposite effect was observed when increasing the moisture content. The in vitro digestibility of JFSS was significantly improved after IECT, due to destruction of starch supramolecular structure according to principal component analysis.


Assuntos
Artocarpus/química , Sementes/química , Amido/química , Amilopectina/química , Amilose/análise , Amilose/química , Culinária/métodos , Digestão , Peso Molecular , Análise de Componente Principal , Temperatura
9.
Food Chem ; 336: 127711, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32777656

RESUMO

Wrinkled and round peas (two varieties each type) cultivated in two locations were milled to obtain fine and coarse wrinkled (WPF) and round pea flour (RPF). WPF exhibited markedly increased pasting viscosities at 120 and 140 °C compared with 95 °C. Overall, the pasting properties of WPF were considerably lower than those of RPF. Resistant starch (RS) contents of cooked WPF (17.2-22.2%, dsb) were significantly larger than those of RPF (7.9-11.4%), resulting from higher starch gelatinization temperatures, greater amylose contents, and presence of more protein and fiber in WPF. The two particle sizes affected the water-holding capacity (WHC) of WPF, gelatinization enthalpy changes (ΔH) of WPF and RPF, and pasting properties and starch digestibility of RPF. Pearson correlation and principal component analysis (PCA) were conducted to reveal the relationships among the techno-functional parameters of pea flours. Wrinkled pea showed promise to generate new pea flours with distinct functionality and enhanced nutritional value.


Assuntos
Farinha , Ervilhas/química , Amilose/química , Fibras na Dieta/metabolismo , Digestão , Farinha/análise , Valor Nutritivo , Tamanho da Partícula , Proteínas de Vegetais Comestíveis/análise , Amido/química , Amido/farmacocinética , Temperatura , Viscosidade
10.
Food Chem ; 336: 127636, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32805513

RESUMO

Deposition of both lignin and cellulose accompanied by juice sac granulation is widespread in harvested citrus fruit. Hence, measures to suppress postharvest granulation of 'Majiayou' pummelo is of great importance. The fruit was treated with 1.5% chitosan and then stored at room temperature (20 ± 2 °C) for 150 d. As compared to the control fruits, chitosan coating significantly suppressed granulation index and maintained good quality. Chitosan coating inhibited lignification by suppressing the activities and expression levels of lignin synthesis-related enzymes (PAL, CAD and POD). By contrast, chitosan treatment enhanced the activities and expression levels of cell wall degrading enzymes, including PME, PG, Cx, XTH and ß-Gal, which might contribute to the decrease in cellulose. In a nutshell, chitosan coating can effectively suppress juice sac granulation and fruit senescence of pummelo fruits, and play a crucial role in maintaining the cell wall modification.


Assuntos
Parede Celular/efeitos dos fármacos , Quitosana/farmacologia , Citrus/efeitos dos fármacos , Armazenamento de Alimentos , Frutas/efeitos dos fármacos , Parede Celular/química , Parede Celular/metabolismo , Celulose/metabolismo , Citrus/metabolismo , Enzimas/genética , Enzimas/metabolismo , Conservantes de Alimentos/farmacologia , Frutas/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Lignina/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Análise de Componente Principal , Temperatura
11.
Food Chem ; 338: 127834, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32810810

RESUMO

The use of starters during fermentation has been gaining momentum as it can warrant high-quality chocolate. The objective of this study was to investigate the influence of Saccharomyces cerevisiae (Sc) and Pichia kudriavzevii (Pk) during on-farm fermentation on physico-chemical and microbiological characteristics and levels of methylxanthines and bioactive amines of cocoa. Four treatments were used: ScPk (1:1), only Sc, only Pk, and no starter (control). The starters lead to changes throughout fermentation, but provided fermented cocoa with similar pH, titratable acidity, reducing sugars and phenolic compounds. ScPk shortened fermentation time by 24 h. The ScPk fermented and dried cocoa had higher levels of monomeric phenols, methylxanthines, phenylethylamine and lower levels of the putrefactive amines - putrescine and cadaverine (p < 0.05). The results were confirmed by multivariate analysis. Based on these results, the mixture of both yeasts species is a promising starter for cocoa fermentation decreasing duration time and modulating high-quality components.


Assuntos
Cacau/química , Cacau/microbiologia , Chocolate/microbiologia , Pichia , Saccharomyces cerevisiae , Aminas/metabolismo , Cafeína/análise , Catequina/análise , Fazendas , Fermentação , Microbiologia de Alimentos , Concentração de Íons de Hidrogênio , Fenóis/análise , Temperatura , Teobromina/análise , Teofilina/análise , Fatores de Tempo
12.
Food Chem ; 338: 127731, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32810811

RESUMO

Pleurotus tuoliensis is a popular edible and medical mushroom, but it is highly perishable during postharvest storage. The quality parameters, chemical composition, malondialdehyde (MDA) concentration, and activity of metabolic enzymes were studied during 12 days of storage at 4 °C and 6 days of storage at 25 °C. Degradation was well described by changes in quality parameters, losses in nutritional value, increased metabolic enzyme activity, the accumulation of MDA concentrations, and the increase of total phenolic (TP) content. The phenylalanine ammonia lyase (PAL) significantly positively correlated with TP, which suggested an underlying mechanism of browning that the increased PAL activity stimulates the biosynthesis of phenols through the phenylalanine pathway. These results suggest that increased activity of laccase, lipoxygenase, PAL, TP and MDA accumulation, together with polysaccharide degradation, are the main factors involved in the deterioration of P. tuoliensis during storage.


Assuntos
Armazenamento de Alimentos , Pleurotus/química , Pleurotus/metabolismo , Aminoácidos/análise , Enzimas/análise , Enzimas/metabolismo , Proteínas Fúngicas/análise , Lacase/análise , Lacase/metabolismo , Malondialdeído/análise , Malondialdeído/metabolismo , Valor Nutritivo , Fenóis/análise , Fenilalanina Amônia-Liase/análise , Fenilalanina Amônia-Liase/metabolismo , Temperatura
13.
Chemosphere ; 262: 127836, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32805657

RESUMO

Polyacrylonitrile fiber was successfully modified with triazine-based dendrimer via grafting method as a promising adsorbent for removal of mercury species from aqueous media. The prepared adsorbent was characterized by elemental analysis, scanning electron microscope, Fourier transform infrared spectroscopy, porous structure analysis and X-ray photoelectron spectroscopy, providing the evidence of successful fabrication. The adsorption conditions were found via varying pH, dosage, coexisting substances, contact time, temperature and concentration. Adsorption performance, described better by the pseudo-second-order kinetics with intraparticle diffusion as rate controlling step and Langmuir isotherm model, indicated a chemisorption process with the maximum Langmuir adsorption amount of 227.64 mg g-1 for mercury ions. Thermodynamically, adsorption of mercury ions was spontaneous and endothermic. Desorption and regeneration experiments demonstrated that it could be reused in five successive adsorption cycles without significant loss of its original performance. Experimental data and density functional theory calculation disclosed the coordination geometries and chelating mechanism between the adsorbent and mercury ions. The proposed study would provide a new prospect for the purification of mercury in aqueous system by functionalizing commercial polyacrylonitrile fiber with dendrimers.


Assuntos
Resinas Acrílicas/química , Dendrímeros/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Difusão , Concentração de Íons de Hidrogênio , Íons/análise , Cinética , Mercúrio/análise , Temperatura , Termodinâmica , Águas Residuárias/química , Água/química , Poluentes Químicos da Água/análise
14.
Chemosphere ; 262: 127602, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32750589

RESUMO

A 1 L lab-scale anaerobic ammonium oxidation (anammox) biofilm reactor with nitrogen loading rate of 0.11 g/L d was run for 110 days with the operation temperature declining from 36 °C to 15 °C. The total inorganic nitrogen removal efficiency showed a reduction from 80% to 66%, when the temperature declined from 36 °C to 15 °C. N-acyl-l-homoserine lactones (AHLs) concentrations, especially C8-HSL and C6-HSL, declined in both water and biomass phases, and this decline indicated that the quorum sensing weakened. Microbial community analysis revealed that Candidatus Kuenenia was the predominant anammox bacteria during the entire operating period. The abundance of Candidatus Kuenenia increased from 1.43% to 22.89% when the temperature decreasing from 36 °C to 15 °C. The correlation between microbial genus and AHLs was complicated. Overall, the temperature decrease weakened the quorum sensing so that the nitrogen removal performance deteriorated, and increasing the anammox activity might be an efficient way to improve performance.


Assuntos
Reatores Biológicos/microbiologia , Homosserina/metabolismo , Lactonas/metabolismo , Microbiota , Bactérias/classificação , Biofilmes , Biomassa , Nitrogênio , Oxirredução , Percepção de Quorum , Temperatura
15.
Chemosphere ; 262: 127895, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32799151

RESUMO

In order to improve the adsorption efficiency of ammonia nitrogen in low temperature wastewater, the modified activated carbon (Fe-AC) was prepared by impregnation-calcination modification of Fe(NO3)3. The characterization results indicated that the total pore volume, specific surface area and the point of zero charge of activated carbon increased after modification. A better adsorption effect was achieved under neutral condition than under alkaline or acidic condition. The effect of Ca2+ on competitive adsorption of NH4+ was greater than that of Na+ when both cations were present. Pseudo-first-order kinetic model was confirmed to be consistent with Fe-AC adsorption kinetic data, and Langmuir model was consistent with adsorption isotherm data. The adsorption thermodynamics demonstrated that the ammonia nitrogen adsorption process by Fe-AC was spontaneous and low-temperature was helpful to improve the adsorption capacity. The mechanism of adsorption of ammonia nitrogen by Fe-AC was the comprehensive effect of physical adsorption and chemical adsorption, which was the essential reason for improving the adsorption efficiency of ammonia nitrogen by Fe-AC at a low temperature. This research offered a new way for the modification of activated carbon and a new method for the removal of ammonia nitrogen at a low temperature.


Assuntos
Amônia/química , Carvão Vegetal/química , Águas Residuárias/química , Poluentes Químicos da Água/química , Adsorção , Temperatura Baixa , Ferro/química , Cinética , Nitrogênio/química , Temperatura , Termodinâmica , Poluentes Químicos da Água/análise
16.
Chemosphere ; 262: 127904, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32799153

RESUMO

Manganese accumulated in corrosion scales on drinking water distribution systems (DWDSs) can be released into bulk water, causing discolouration and thereby leading to customer concerns about drinking water quality. A static release experiment was conducted on iron pipe scales under three different temperatures, pH values, alkalinity values, sulfate (SO42-) concentrations, and disinfectants to study the separate effect of these factors on Mn release from pipe scales under stagnant conditions. Results showed that more Mn was released from corrosion scales under the conditions of lower pH, lower alkalinity, higher temperature, and higher SO42- concentrations. Three commonly used disinfectants, sodium hypochlorite (NaClO), chlorine dioxide (ClO2), and monochloramine (NH2Cl) were found to inhibit the release of Mn from iron corrosion scales, with the ranked order of inhibitory effect of ClO2≈NaClO > NH2Cl under the same CT (product of disinfectant concentration and contact time) value. The orthogonal experimental results indicated that SO42- and alkalinity had extremely significant effects on the release of Mn from pipe scales, while pH and disinfectant type had a significant impact on the release of Mn from pipe scales. Thus, the SO42- concentration and alkalinity of the bulk water should be determined to avoid excessive release of Mn into drinking water. However, further investigation of the effect of disinfectants on Mn release in DWDSs is necessary. This research helps establish a systematic understanding of the influential factors in Mn release from pipe scales into bulk water, as well as their significant relationships.


Assuntos
Água Potável/química , Manganês/análise , Poluentes Químicos da Água/análise , Compostos Clorados , Corrosão , Desinfetantes/análise , Concentração de Íons de Hidrogênio , Ferro , Óxidos , Sulfatos/análise , Temperatura , Qualidade da Água , Abastecimento de Água
17.
Chemosphere ; 262: 127924, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32805661

RESUMO

Cr(VI) compounds at high temperature usually tend to decompose and reduce into Cr(III) due to thermodynamically instability for Cr(VI). This study found Cr(VI) could be reduced into Cr(V) instead of Cr(III) in the presence of CaO during heating solid waste containing Cr(VI). CaCrO4 is prepared and mixed with CaO as simulated solid waste containing Cr(VI). It was found that CaCrO4 reacted with CaO and formed a new product Ca5(CrO4)3O0.5 at temperature range of 800 and 1000 °C. The valence state of Cr in Ca5(CrO4)3O0.5 is determined to be +5 b y XPS analysis, and the color for new formed Cr(V) is observed in green, similar to Cr(III) compounds. The temperature and CaO are two keys to arouse the reduction reaction of Cr(VI) into Cr(V). In particular, the reduction of Cr(VI) into Cr(V) is strongly depended on temperature (800-1000 °C), this reaction can be balanced within 10 min, while prolonging sintering time has little help for promoting the reduction of Cr(VI) to Cr(V). Additionally, it was found Cr(V) can keep stable and not be re-oxidized into Cr(VI) at 800-1000 °C. Above results offers some new understanding and knowledge about the formation of Cr(V) in presence of much CaO or CaCO3 during heating solid waste containing Cr(VI).


Assuntos
Cromo/química , Eliminação de Resíduos/métodos , Hidróxido de Cálcio/química , Calefação , Temperatura Alta , Oxirredução , Resíduos Sólidos , Temperatura
18.
Sci Total Environ ; 751: 141728, 2021 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-32890797

RESUMO

Trees significantly impact land-atmosphere feedbacks through evapotranspiration, photosynthesis and isoprene emissions. These processes influence the local microclimate, air quality and can mitigate temperature extremes and sequester carbon dioxide. Despite such importance, currently only 5 out of 15 atmospheric chemistry climate models even partially account for the presence of cropland trees. We first show that the tree cover over intensely farmed regions in Asia, Australia and South America is significantly underestimated (e.g. only 1-3% tree cover over north-India) in the Model of Emissions of Gases and Aerosol from Nature (MEGAN) and absent in Noah land-surface module of the Weather Research and Forecasting (WRF-Chem) Model. By including the actual tree cover (~10%) over the north-west Indo Gangetic Plain in the Noah land-surface module of the WRF-Chem and the MEGAN module, during the rice growing monsoon season in August, we find that the latent heat flux alone increases by 100%-300% while sensible heat flux reduces by 50%-100%, leading to a reduction in daytime boundary layer height by 200-400 m. This greatly improves agreement between the modelled and measured temperature, boundary layer height and surface ozone, which were earlier overestimated and isoprene and its oxidation products which were earlier underestimated. Mitigating peak daytime temperatures and ozone improves rice production by 10 to 20%. Our findings from north west Indo-Gangetic Plain establish that such plantations mitigate heat stress, and have beneficial effects on crop yields while also sequestering carbon. Expanding agroforestry practices to 50% of the cropland area could result in up to 40% yield gain regionally. Implementing such strategies globally could increase crop production and sequester 0.3-30 GtC per year, and therefore future climate mitigation and food security efforts should consider stakeholder participation for increased cropland agroforestry in view of its beneficial effects.


Assuntos
Poluentes Atmosféricos , Ozônio , Poluentes Atmosféricos/análise , Ásia , Atmosfera , Austrália , Produtos Agrícolas , Monitoramento Ambiental , Índia , Ozônio/análise , América do Sul , Temperatura , Árvores
19.
Sci Total Environ ; 750: 141484, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32829260

RESUMO

The SARS-CoV-2 is a novel coronavirus identified as the cause of COVID-19 and, as the pandemic evolves, many have made parallels to previous epidemics such as SARS-CoV (the cause of an outbreak of severe acute respiratory syndrome [SARS]) in 2003. Many have speculated that, like SARS, the activity of SARS-CoV-2 will subside when the climate becomes warmer. We sought to determine the relationship between ambient temperature and COVID-19 incidence in Canada. We analyzed over 77,700 COVID-19 cases from four Canadian provinces (Alberta, British Columbia, Ontario, and Quebec) from January to May 2020. After adjusting for precipitation, wind gust speed, and province in multiple linear regression models, we found a positive, but not statistically significant, association between cumulative incidence and ambient temperature (14.2 per 100,000 people; 95%CI: -0.60-29.0). We also did not find a statistically significant association between total cases or effective reproductive number of COVID-19 and ambient temperature. Our findings do not support the hypothesis that higher temperatures will reduce transmission of COVID-19 and warns the public not to lose vigilance and to continue practicing safety measures such as hand washing, social distancing, and use of facial masks despite the warming climates.


Assuntos
Infecções por Coronavirus , Pandemias , Pneumonia Viral , Alberta , Betacoronavirus , Colúmbia Britânica/epidemiologia , Humanos , Incidência , Ontário , Quebeque , Temperatura
20.
Sci Total Environ ; 752: 141705, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32892039

RESUMO

E. coli survival in biosolids storage may present a risk of non-compliance with guidelines designed to ensure a quality product safe for agricultural use. The storage environment may affect E. coli survival but presently, storage characteristics are not well profiled. Typically biosolids storage environments are not actively controlled or monitored to support increased product quality or improved microbial compliance. This two-phased study aimed to identify the environmental factors that control bacterial concentrations through a long term, controlled monitoring study (phase 1) and a field-scale demonstration trial modifying precursors to bacterial growth (phase 2). Digested and dewatered biosolids were stored in operational-scale stockpiles to elucidate factors controlling E. coli dynamics. E. coli concentrations, stockpile dry solids, temperature, redox and ambient weather data were monitored. Results from ANCOVA analysis showed statistically significant (p < 0.05) E. coli reductions across storage periods with greater die-off in summer months. Stockpile temperature had a statistically significant effect on E. coli survival. A 4.5 Log reduction was measured in summer (maximum temperature 31 °C). In the phase 2 modification trials, covered stockpiles were able to maintain a temperature >25 °C for a 28 day period and achieved a 3.7 Log E. coli reduction. In winter months E. coli suppression was limited with concentrations >6 Log10 CFU g-1 DS maintained. The ANCOVA analysis has identified the significant role that physical environmental factors, such as stockpile temperature, has on E. coli dynamics and the opportunities for control.


Assuntos
Escherichia coli , Esgotos , Agricultura , Bactérias , Biossólidos , Contagem de Colônia Microbiana , Temperatura
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