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1.
Sensors (Basel) ; 21(19)2021 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-34640662

RESUMO

Over the past few decades, the concentrating photovoltaic systems, a source of clean and renewable energy, often fully integrated into the roof structure, have been commonly installed on private houses and public buildings. The purpose of those panels is to transform the incoming solar radiation into electricity thanks to the photovoltaic effect. The produced electric power is affected, in the first instance, by the solar panel efficiency and its technical characteristics, but it is also strictly dependent on site elevation, the meteorological conditions and on the presence of the atmospheric constituents, i.e., clouds, hydrometeors, gas molecules and sub-micron-sized particles suspended in the atmosphere that can scatter and absorb the incoming shortwave solar radiation. The Aerosol Optical Depth (AOD) is an adimensional wavelength-dependent atmospheric column variable that accounts for aerosol concentration. AOD can be used as a proxy to evaluate the concentration of surface particulate matter and atmospheric column turbidity, which in turn affects the solar panel energy production. In this manuscript, a new technique is developed to retrieve the AOD at 550 nm through an iterative process: the atmospheric optical depth, incremented in steps of 0.01, is used as input together with the direct and diffuse radiation fluxes computed by Fu-Liou-Gu Radiative Transfer Model, to forecast the produced electric energy by a photovoltaic panel through a simple model. The process will stop at that AOD value (at 550 nm), for which the forecast electric power will match the real produced electric power by the photovoltaic panel within a previously defined threshold. This proof of concept is the first step of a wider project that aims to develop a user-friendly smartphone application where photovoltaic panel owners, once downloaded it on a voluntary basis, can turn their photovoltaic system into a sunphotometer to continuously retrieve the AOD, and more importantly, to monitor the air quality and detect strong air pollution episodes that pose a threat for population health.


Assuntos
Poluição do Ar , Energia Solar , Aerossóis , Poluição do Ar/análise , Atmosfera , Material Particulado
2.
Sensors (Basel) ; 21(19)2021 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-34640731

RESUMO

The features of the atmospheric γ-background reaction to liquid atmospheric precipitation in the form of bursts is investigated, and various forms of them are analyzed. A method is described for interpreting forms of the measured γ-background response with the determination of the beginning and ending time of precipitation, the distinctive features of changes in the intensity of precipitation and the number of single (separate) events that form one burst. It is revealed that a change in the intensity of precipitation in one event leads to a change in the γ-radiation dose rate increase speed (time derivative). A method of estimating the average value of the intensity and amount of precipitation for one event, reconstructing the intensity spectrum from experimental data on the dynamics of the measured dose rate of γ-radiation, is developed. The method takes into account the radioactive decay of radon daughter products in the atmosphere and on the soil surface during precipitation, as well as the purification of the atmosphere from radionuclides. Recommendations are given for using the developed method to correct for changes (daily variations) in radon flux density from the ground surface, which lead to variations in radon in the atmosphere. Experimental verification of the method shows good agreement between the values of the intensity of liquid atmospheric precipitation, calculated and measured with the help of shuttle and optical rain precipitation gauges.


Assuntos
Poluentes Radioativos do Ar , Radônio , Poluentes Radioativos do Ar/análise , Atmosfera , Raios gama , Chuva
3.
Anal Chim Acta ; 1179: 338835, 2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-34535252

RESUMO

Although electron impact ionization (EI) remains the standard ionization source for GC-MS, it presents extensive fragmentation as its main limitation. The potential of a novel plasma-based soft ionization source named controlled-atmosphere flexible microtube plasma (CA-FµTP) has been evaluated in this work for the determination of monoaromatic volatile BTEX group (namely benzene, toluene, ethylbenzene, and o-, m- and p-xylenes) in olive oil, based on headspace technique. The obtained results show an attractive advantage over EI due to no fragmentation was observed. A nitrosated ion [M + NO]+ is obtained as the most abundant species. Thus, the BTEX mass spectrum identification can be carried out without major effort. In general, the sensitivity for CA-FµTP was comparable to those obtained by EI, achieving LODs ranged from 0.6 to 1.0 µg kg-1. The potential usefulness of GC-CA-FµTP-MS for the detection of BTEX was demonstrated by analyzing olive oil samples and identifying traces of these compounds in one sample. Therefore, the proposed plasma-based soft ionization is suitable for BTEX analysis in fatty complex matrixes as olive oil.


Assuntos
Derivados de Benzeno , Xilenos , Atmosfera , Benzeno/análise , Derivados de Benzeno/análise , Cromatografia Gasosa-Espectrometria de Massas , Espectrometria de Massas , Azeite de Oliva , Tolueno/análise , Xilenos/análise
4.
Molecules ; 26(17)2021 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-34500555

RESUMO

The deterioration of food quality due to lipid oxidation is a serious problem in the food sector. Oxidation reactions adversely affect the physicochemical properties of food, worsening its quality. Lipid oxidation products are formed during the production, processing, and storage of food products. In the human diet, the sources of lipid oxidation products are all fat-containing products, including goose meat with a high content of polyunsaturated fatty acids. This study aims at comparing the fatty acid profile of goose breast muscle lipids depending on the storage conditions: type of atmosphere, temperature, and storage time. Three-way variance analysis was used to evaluate changes in the fatty acids profile occurring in goose meat. The health aspect of fatty acid oxidation of goose meat is also discussed. In general, the fatty acid composition changed significantly during storage in the meat packed in the high-oxygen modified atmosphere at different temperatures (1 °C and 4 °C). Higher temperature led to a higher degree of lipid oxidation and nutrient loss. During the storage of samples in vacuum, no changes in the fatty acid content and dietary indices were found, regardless of the storage temperature, which indicates that the anaerobic atmosphere ensured the oxidative stability of goose meat during 11 days of refrigerated storage.


Assuntos
Ácidos Graxos/metabolismo , Gansos/metabolismo , Carne/análise , Animais , Atmosfera , Dieta/métodos , Embalagem de Alimentos/métodos , Qualidade dos Alimentos , Metabolismo dos Lipídeos/fisiologia , Lipídeos/química , Oxirredução , Músculos Peitorais/metabolismo , Temperatura , Vácuo
6.
J Agric Food Chem ; 69(38): 11440-11450, 2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34520209

RESUMO

Two simple and low-cost QuEChERS approaches were optimized and validated for multimycotoxin determination in grains by UPLC-MS/MS and applied to assess effectiveness of controlled atmosphere (CA) storage in preventing mycotoxin contamination. Common bean, soybean, and maize samples were stored for 6 months. CA treatments were conducted varying O2 and CO2 partial pressures, temperatures, and moisture contents of the chambers. In the validation study for common bean and maize, 8 out of 11 mycotoxins were successfully validated. For soybean, 10 out of 11 mycotoxins were validated. Aflatoxin B1 was detected in all commodities. Statistical tests suggest that storage temperature played a key role in aflatoxin B1 concentrations in common bean and soybean, but had no influence on maize. Maize was also positive for fumonisins B1 and B2. Differences in fumonisin concentrations were not significant among different treatments. Concentrations of aflatoxin B1 in some samples exceeded legislation's maximum levels. Thus, some of the CA treatments applied were effective in preventing mycotoxin contamination in common bean and soybean but were not effective for maize.


Assuntos
Micotoxinas , Atmosfera , Cromatografia Líquida , Contaminação de Alimentos/análise , Micotoxinas/análise , Espectrometria de Massas em Tandem
7.
Nature ; 597(7876): 366-369, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34526704

RESUMO

Southeast Australia experienced intensive and geographically extensive wildfires during the 2019-2020 summer season1,2. The fires released substantial amounts of carbon dioxide into the atmosphere3. However, existing emission estimates based on fire inventories are uncertain4, and vary by up to a factor of four for this event. Here we constrain emission estimates with the help of satellite observations of carbon monoxide5, an analytical Bayesian inversion6 and observed ratios between emitted carbon dioxide and carbon monoxide7. We estimate emissions of carbon dioxide to be 715 teragrams (range 517-867) from November 2019 to January 2020. This is more than twice the estimate derived by five different fire inventories8-12, and broadly consistent with estimates based on a bottom-up bootstrap analysis of this fire episode13. Although fires occur regularly in the savannas in northern Australia, the recent episodes were extremely large in scale and intensity, burning unusually large areas of eucalyptus forest in the southeast13. The fires were driven partly by climate change14,15, making better-constrained emission estimates particularly important. This is because the build-up of atmospheric carbon dioxide may become increasingly dependent on fire-driven climate-carbon feedbacks, as highlighted by this event16.


Assuntos
Dióxido de Carbono/análise , Imagens de Satélites , Incêndios Florestais/estatística & dados numéricos , Atmosfera/química , Austrália , Teorema de Bayes , Monóxido de Carbono/análise , Mudança Climática , Eucalyptus , Florestas , Pradaria , Incerteza
8.
Sensors (Basel) ; 21(18)2021 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-34577238

RESUMO

In this paper, we describe the possibility of using the energy of a compressed air flow, where cryogenic temperatures are achieved within the flow behind the nozzle, when reaching a critical flow in order to maximize the energy gained. Compared to the energy of compressed air, the energy obtained thermoelectrically is negligible, but not zero. We are therefore primarily aiming to maximize the use of available energy sources. Behind the aperture separating regions with a pressure difference of several atmospheres, a supersonic flow with a large temperature drop develops. Based on the Seebeck effect, a thermocouple is placed in these low temperatures to create a thermoelectric voltage. This paper contains a mathematical-physical analysis for proper nozzle design, controlled gas expansion and ideal placement of a thermocouple within the flow for best utilization of the low temperature before a shockwave formation. If the gas flow passes through a perpendicular shockwave, the velocity drops sharply and the gas pressure rises, thereby increasing the temperature. In contrast, with a conical shockwave, such dramatic changes do not occur and the cooling effect is not impaired. This article also contains analyses for proper forming of the head shape of the thermocouple to avoid the formation of a detached shockwave, which causes temperature stagnation resulting in lower thermocouple cooling efficiency.


Assuntos
Ar Comprimido , Atmosfera , Temperatura Baixa , Pressão , Temperatura
9.
Nature ; 597(7876): 370-375, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34526706

RESUMO

Droughts and climate-change-driven warming are leading to more frequent and intense wildfires1-3, arguably contributing to the severe 2019-2020 Australian wildfires4. The environmental and ecological impacts of the fires include loss of habitats and the emission of substantial amounts of atmospheric aerosols5-7. Aerosol emissions from wildfires can lead to the atmospheric transport of macronutrients and bio-essential trace metals such as nitrogen and iron, respectively8-10. It has been suggested that the oceanic deposition of wildfire aerosols can relieve nutrient limitations and, consequently, enhance marine productivity11,12, but direct observations are lacking. Here we use satellite and autonomous biogeochemical Argo float data to evaluate the effect of 2019-2020 Australian wildfire aerosol deposition on phytoplankton productivity. We find anomalously widespread phytoplankton blooms from December 2019 to March 2020 in the Southern Ocean downwind of Australia. Aerosol samples originating from the Australian wildfires contained a high iron content and atmospheric trajectories show that these aerosols were likely to be transported to the bloom regions, suggesting that the blooms resulted from the fertilization of the iron-limited waters of the Southern Ocean. Climate models project more frequent and severe wildfires in many regions1-3. A greater appreciation of the links between wildfires, pyrogenic aerosols13, nutrient cycling and marine photosynthesis could improve our understanding of the contemporary and glacial-interglacial cycling of atmospheric CO2 and the global climate system.


Assuntos
Monitoramento Ambiental , Eutrofização , Fitoplâncton/crescimento & desenvolvimento , Fitoplâncton/isolamento & purificação , Incêndios Florestais/estatística & dados numéricos , Aerossóis/análise , Aerossóis/química , Atmosfera/química , Austrália , Clorofila A/análise , Imagens de Satélites , Estações do Ano , Fuligem/análise
10.
J Hazard Mater ; 416: 126168, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492944

RESUMO

As an issue of great concern, microplastics pollution has emerged as a key environmental challenge of our time. The atmosphere is a significant compartment in the global cycle of microplastics, however, studies on the transport and deposition of airborne microplastics is limited. In the present work, atmospheric wet and dry deposition of microplastics were analyzed over one year in an urban environment of megacity Guangzhou, China. The atmospheric deposition fluxes of microplastics ranged from 51 to 178 particles/m2/d (mean: 114 ± 40 particles/m2/d). Fibers, fragments, films and microbeads were observed in the deposition samples, with fibers being the most abundant microplastics, accounting for 77.6 ± 19.1% of the total. The chemical composition of microplastics were identified using micro Fourier transform infrared spectrometer. 78.7% of the fibrous microplastics were derived from petrochemicals and most were polyethylene terephthalate (polyester), suggesting that textiles (e.g., clothes and curtains) were likely the main source. The results of back-trajectory analysis indicated that city rivers may act as secondary sources of airborne microplastics. Though no significant correlation was found between atmospheric microplastic deposition and meteorological factors such as rainfall and wind events, these factors were suggested to be positive drivers for the transport and deposition of airborne microplastic.


Assuntos
Microplásticos , Poluentes Químicos da Água , Atmosfera , Monitoramento Ambiental , Plásticos , Rios , Poluentes Químicos da Água/análise
11.
Huan Jing Ke Xue ; 42(10): 4602-4610, 2021 Oct 08.
Artigo em Chinês | MEDLINE | ID: mdl-34581102

RESUMO

To reveal the characteristics of photochemical pollution in North China, adsorbing columns with 2, 4-dinitrophenylhydrazine(DNPH) were used to sample carbonyl compounds in Shijiazhuang and Xinglong between May 2018 and April 2019. The samples were analyzed by high-performance liquid chromatography to understand the composition, volume fraction, source, ·OH loss rate, and ozone formation potential of the carbonyl compounds. A total of 13 carbonyl compounds containing carbonyl groups were determined, of which acetone, formaldehyde, and acetaldehyde were highest at(6.46±5.25)×10-9, (3.76±2.29×10-9), and(2.65±1.74)×10-9 in Shijiazhuang compared to(1.85±1.27)×10-9, (1.29±1.02)×10-9, and(0.72±0.48)×10-9 in Xinglong, respectively. The estimated maximum ozone formation potential(OFP) of formaldehyde was much higher than that of acetaldehyde; the C1/C2 and C2/C3 ozone formation potential(OFP) of formaldehyde was much higher than that of acetaldehyde; and the C1/C2 and C2/C3 values showed that vehicle exhaust and fossil fuel combustion were the main sources in Shijiazhuang in association with the higher level of industrialization. In Xinglong, the carbonyl compounds mainly originated from natural sources. Acetaldehyde(1.77 s-1), formaldehyde(1.57 s-1), and butyraldehyde(0.42 s-1) contributed most to L·OH in Shijiazhuang, and formaldehyde(0.53 s-1), acetaldehyde(0.47 s-1), and butyraldehyde(0.12 s-1) were the three main contributors to L·OH in Xinglong. The carbonyl compounds contributing most to O3 production were formaldehyde and acetaldehyde at(34.61×10-9 O3) and (16.73×10-9 O3) in Shijiazhuang, compared to (11.77×10-9 O3) and (4.47×10-9 O3) in Xinglong, respectively.


Assuntos
Poluentes Atmosféricos , Poluentes Atmosféricos/análise , Atmosfera , China , Monitoramento Ambiental , Emissões de Veículos/análise
12.
J Agric Food Chem ; 69(35): 10281-10291, 2021 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-34432462

RESUMO

Food wastage represented by the deterioration of perishable food like fruits and vegetables is a serious global problem with tremendous ethical, financial, and environmental costs. The atmosphere (CO2 and O2) has a crucial role in food storage and can regulate physiological food metabolism and microbial growth. Modified atmosphere packaging (MAP) is a promising method used to extend shelf life and preserve the quality of perishable food; yet, its use depends on the specific gas permeability and selectivity of polymer membranes to generate an atmosphere desirable for storage. In this study, we established and validated a new plant leaf-mimetic shellac-based MAP membrane embedded with chitosan porous microspheres loaded with antimicrobial tannic acid (TA-CPM) as gas "switches" for regulating O2 and CO2 permeability and CO2/O2 selectivity. The effects of different amounts of TA-CPM added into the hybrid membranes were examined for litchi preservation at room temperature. Our results showed that this hybrid TA-CPM/shellac packaging membrane could regulate the internal CO2 and O2 concentrations and the CO2/O2 ratio within the packages containing litchis by adjusting the addition amount of TA-CPM. The 0.05% TA-CPM/shellac and 0.10% TA-CPM/shellac packages, especially 0.05% TA-CPM/shellac, generated a more desirable CO2 and O2 atmosphere for litchi preservation compared with controls, which was reflected by the delaying of browning and rotting, maintaining of the natural color of the litchi pericarp, preservation of pulp quality, inhibition of polyphenol oxidase and guaiacol peroxidase activities, and reduction of oxidative cell damage in litchis. The results suggested that 0.05% TA-CPM/shellac and 0.10% TA-CPM/shellac packaging membranes, especially 0.05% TA-CPM/shellac, could generate an ideal atmosphere for litchi storage at room temperature, demonstrating that this permeation-controlled hybrid membrane has great potential in food preservation and other applications requiring a modified atmosphere.


Assuntos
Litchi , Atmosfera , Microbiologia de Alimentos , Embalagem de Alimentos , Conservação de Alimentos , Frutas , Microesferas , Oxigênio , Porosidade
13.
J Phys Chem A ; 125(35): 7705-7715, 2021 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-34459596

RESUMO

Pyrethroid, a pesticide widely used worldwide, could mimic, block, or synergize the effects of endogenous hormones in humans or mammals after entering into the atmosphere and after being sprayed and applied in large quantities. This research aims to study the mechanism, kinetics, and eco-toxicity evaluation of the ozonolysis of permethrin (PER)-one of the typical pyrethroid (type I) pesticides. Existing experimental studies only predicted that ozonolysis of PER could generate a cycloperoxy analogue of PER (IM13-1-11), and the reaction mechanism has not yet been completed. To make up for the lack of experimental results, the 13 primary reaction pathways of PER and ozone, as well as the subsequent reactions of Criegee intermediates with small molecules such as NOx, COx, SO2, and O2, have been studied to propose new reaction paths by quantum chemical calculations in this work. We calculated the total reaction rate constant of PER and ozone at 298 K and 1 atm based on the calculated thermodynamic data and the transition state theory (TST), which was compared with the experimental values to prove the reliability of our results. Based on the quantitative structure and activity relationship, we predicted the acute and chronic toxicity of PER and its products of ozonolysis to three representative organisms-fish, daphnia, and green algae to avoid animal experiments. The results show that ozonolysis products of PER are still extremely harmful to the environment and should be taken seriously, although the products have less toxicity than PER.


Assuntos
Atmosfera/química , Ozônio/química , Permetrina/química , Permetrina/toxicidade , Humanos , Cinética , Reprodutibilidade dos Testes , Termodinâmica
14.
J Environ Radioact ; 237: 106690, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34358898

RESUMO

The particle size distributions of airborne aerosols with 7Be were measured using cascade impactors at Dazaifu, a city in western Japan, in 2018 to observe their seasonal variation. Beryllium-7 was found to be adsorbed to aerosols with a particle size of less than 2.1 µm; in general, particles sized 0.43-0.65 µm had the highest 7Be activity concentrations. The activity median aerodynamic diameter (AMAD) of 7Be fluctuated less over the year within the range of 0.40-0.52 µm, which is the size range of particles that can reach human alveoli, and had an annual mean of 0.43 ± 0.034 µm. The activity concentrations of 7Be were significantly lower in summer, which affected 7Be activity concentration for each particle size fraction. The particle size distribution of 7Be-carrying aerosols was also affected by that of the aerosol particles in the atmosphere. Finally, findings suggest that 7Be was mainly adsorbed to sulfate aerosols (particularly ammonium sulfate aerosols).


Assuntos
Poluentes Radioativos do Ar , Monitoramento de Radiação , Aerossóis/análise , Poluentes Radioativos do Ar/análise , Atmosfera , Humanos , Japão , Tamanho da Partícula
15.
Anal Methods ; 13(34): 3799-3805, 2021 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-34368829

RESUMO

A system for controlled generation of peracetic acid (PAA) atmospheres used to test and evaluate sampling and measurement devices was developed and characterized. Stable atmospheric conditions were maintained in a dynamic flow system for hours while multiple sensors were simultaneously exposed to equivalent atmospheres of PAA vapors. Atmospheres characterized by a range of PAA concentrations at a controlled flow rate, temperature, and humidity were generated. Presented herein is a system for vaporization of PAA solutions to generate controlled atmospheres with less than 3% relative standard deviation (RSD) of the PAA concentrations over time.


Assuntos
Atmosfera , Ácido Peracético
16.
Food Res Int ; 147: 110483, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34399479

RESUMO

This study aimed to evaluate the effects of low oxygen partial pressure (pO2) and high carbon dioxide partial pressure (pCO2) combined with different temperatures on the oil acidity and peroxide values of two soybean cultivars (NA 5909 RG and FEPAGRO 37 RR). The volatile compounds correlated to lipid oxidation were also evaluated. Soybeans were stored for seven months under ambient and controlled atmosphere (CA) conditions at three temperatures (20, 25, and 30 °C). Storage under ambient conditions increased acidity and peroxide value regardless of the temperature. CA storage with low pO2 reduced oil acidity and its combination with high pCO2 had no positive effects on oil acidity and peroxide values. Grains of FEPAGRO 37 RR stored under ambient air showed higher 1-octne-3-ol amount compared to CA. The higher storage temperature increased (E)-2-heptenal and decanal amount in grains of cultivar NA 5909 RG. In addition, the ambiente air storage provide higher γ-Butyrolactone in relation to CA storage. Moreover, in both cultivars the CA storage technique provides lower (E)-2-hexenal content. This compound, together with hexanal are potential lipid deterioration markers of soybeans. CA storage is a promising tool for soybean grains preservation and the effect is mainly due to the oxygen reduction, with no additional effect of CO2 increasing.


Assuntos
Atmosfera , Soja , Lipídeos , Oxirredução , Temperatura
17.
Food Res Int ; 147: 110491, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34399487

RESUMO

The present study aimed to investigate the effect of chitosan edible coating containing 0.15% oregano essential oil (OEO) or 0.60% cinnamon essential oil (CEO) on the quality characteristics and dynamic changes in the bacterial community of roast duck slices under modified atmosphere packaging (MAP, 30% CO2/70% N2) during 21 days of storage at 2 ± 2 °C. The results showed that the application of chitosan coating (CH) alone inhibited the growth of microorganisms and prevented lipid oxidation throughout storage. Moreover, the storage stability was further improved by including OEO or CEO, which lowered (P < 0.05) values for total viable count (TVC), Enterobacteriaceae, 2-thiobarbituric acid reactive substance (TBARS) and total volatile basic nitrogen (TVB-N). Based on the microbiological results, the shelf-life of CH-OEO and CH-CEO treated roast duck slices was prolonged by at least 7 days compared to that of the control. In addition, packaging types applied in this study played a major role in the bacterial community development. Notably, Vibrio spp. were the most predominant bacteria in all samples, when TVC values approached the shelf-life threshold, suggesting that this bacterium may be the main contributor to the spoilage of roast duck. The growth inhibition of Vibrio spp. in the CH-OEO and CH-CEO treatments during the early period of chilled storage might be the reason for the extension of the shelf life. Taken together, CH incorporated with OEO or CEO could be developed as prospective edible packaging materials to preserve roast duck meat.


Assuntos
Quitosana , Óleos Voláteis , Origanum , Animais , Atmosfera , Bactérias , Quitosana/farmacologia , Cinnamomum zeylanicum , Patos , Microbiologia de Alimentos , Embalagem de Alimentos , Conservação de Alimentos , Carne , Óleos Voláteis/farmacologia , Estudos Prospectivos
18.
Talanta ; 234: 122712, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34364504

RESUMO

In the atmosphere, fluorine element in rocks is hard to detect using fluorine atomic emission spectrum in laser-induced breakdown spectroscopy. In this study, a novel radical synthesis method based on laser ablation was proposed, by which strontium-fluorine (SrF) radical spectrum was collected to quantify fluorine element in rocks instead of fluorine atom spectrum. A pure strontium carbonate was placed orthogonally to the sample, and ablated by an additional laser to provide sufficient strontium atoms for promoting SrF radical formation. The fluorine content in rocks was sensitively and accurately determined by SrF radical emission signal. The coefficient of determination, average relative standard deviation, root mean square error, limit of detection, and limit of qualification were 0.996, 4.68%, 0.0068 wt%, 6.36 µg g-1, and 21.2 µg g-1, respectively. This work proved that this novel method provides a new way to promote radical synthesis and has considerable potential for detecting fluorine in rocks in geological exploration.


Assuntos
Flúor , Lasers , Atmosfera , Luz , Análise Espectral
19.
Artigo em Inglês | MEDLINE | ID: mdl-34435946

RESUMO

Species belonging to the genus Sphingomonas have been isolated from environments such as soil, water and plant tissues. Many strains are known for their capability of degrading aromatic molecules and producing extracellular polymers. A Gram-stain-negative, strictly aerobic, motile, red-pigmented, oxidase-negative, catalase-positive, rod-shaped strain, designated DH-S5T, has been isolated from pork steak packed under CO2-enriched modified atmosphere. Cell diameters were 1.5×0.9 µm. Growth optima were at 30 °C and at pH 6.0. Phylogenetic analyses based on both complete 16S rRNA gene sequence and whole-genome sequence data revealed that strain DH-S5T belongs to the genus Sphingomonas, being closely related to Sphingomonas alpina DSM 22537T (97.4 % gene sequence similarity), followed by Sphingomonas qilianensis X1T (97.4 %) and Sphingomonas hylomeconis GZJT-2T (97.3 %). The DNA G+C content was 64.4 mol%. The digital DNA-DNA hybridization value between the isolate strain and S. alpina DSM 22537T was 21.0 % with an average nucleotide identity value of 77.03 %. Strain DH-S5T contained Q-10 as the ubiquinone and major fatty acids were C18 : 1 cis 11 (39.3 %) and C16 : 1 cis 9 (12.5 %), as well as C16 : 0 (12.1 %) and C14 : 0 2-OH (11.4 %). As for polar lipids, phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, dimethylphosphatidylethanolamine and sphingoglycolipid could be detected, alongside traces of monomethylphosphatidylethanolamine. Based on its phenotypic, chemotaxonomic and phylogenetic characteristics, strain DH-S5T (=DSM 110829T=LMG 31606T) is classified as a representative of the genus Sphingomonas, for which the name Sphingomonas aliaeris sp. nov. is proposed.


Assuntos
Filogenia , Carne de Porco , Sphingomonas , Animais , Atmosfera , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Microbiologia de Alimentos , Alemanha , Fosfolipídeos/química , Pigmentação , Carne de Porco/microbiologia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Sphingomonas/classificação , Sphingomonas/isolamento & purificação , Suínos
20.
Sci Rep ; 11(1): 16852, 2021 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-34413343

RESUMO

The COVID-19 pandemic caused disruptions of public life and imposed lockdown measures in 2020 resulted in considerable reductions of anthropogenic aerosol emissions. It still remains unclear how the associated short-term changes in atmospheric chemistry influenced weather and climate on regional scales. To understand the underlying physical mechanisms, we conduct ensemble aerosol perturbation experiments with the Community Earth System Model, version 2. In the simulations reduced anthropogenic aerosol emissions in February generate anomalous surface warming and warm-moist air advection which promotes low-level cloud formation over China. Although the simulated response is weak, it is detectable in some areas, in qualitative agreement with the observations. The negative dynamical cloud feedback offsets the effect from reduced cloud condensation nuclei. Additional perturbation experiments with strongly amplified air pollution over China reveal a nonlinear sensitivity of regional atmospheric conditions to chemical/radiative perturbations. COVID-19-related changes in anthropogenic aerosol emissions provide an excellent testbed to elucidate the interaction between air pollution and climate.


Assuntos
COVID-19/epidemiologia , Clima , SARS-CoV-2/fisiologia , Aerossóis , Poluentes Atmosféricos , Atmosfera , COVID-19/transmissão , China , Controle de Doenças Transmissíveis , Extremo Oriente , Humanos , Pandemias , Tempo (Meteorologia)
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