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1.
J Am Soc Mass Spectrom ; 35(5): 839-854, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38587268

RESUMEN

Personal care products (PCPs) are integral components of daily human existence, including a large number of chemicals intentionally added for functional attributes (e.g., preservatives and fragrances) or unintentionally present, such as plasticizers. This investigation aimed to optimize the methodology for target and suspect screening via liquid chromatography-high-resolution mass spectrometry, focusing on nine prevalent organic additives (comprising bisphenols A, F, and S, methyl, ethyl, propyl, and butylparaben, 5-chloro-2-methyl-4-isothiazolin-3-one, and 4-hydroxybenzoic acid). A total of 50 high-selling PCPs were purchased from the local online market as samples. In detail, PCP samples were classified into body washes, shampoos, hair conditioners, facial cleansers, body lotions, and moisture creams. For calibration, the quality assurance and quality control results demonstrated a coefficient of determination (R2) surpassing 0.999, with detection and quantification limits ranging from 2.5 to 100.0 ng/g. For recovery experiments, replicate recoveries (n = 5) ranged from 61 to 134%. In purchased PCP samples, five of the nine target compounds were detected via a target screening. Methylparaben exhibited the highest concentration (7860 mg/kg) in a facial cleanser, which is known as an endocrine-disrupting chemical. A total of 248 suspects of organic additives were screened in PCPs, leading to a tentative identification of 9. Confirmation (confidence level 1) via reference standards was achieved for three suspects, while six were tentatively identified with a confidence level of 2. This two-step extraction methodology utilizing methyl tert-butyl ether and isopropyl alcohol enabled simultaneous analysis of diverse chemical groups with distinct properties.


Asunto(s)
Cosméticos , Parabenos , Cosméticos/química , Cosméticos/análisis , Parabenos/análisis , Cromatografía Liquida/métodos , Límite de Detección , Espectrometría de Masas/métodos , Fenoles/análisis , Fenoles/química , Compuestos de Bencidrilo/análisis , Compuestos de Bencidrilo/química , Tiazoles/análisis , Tiazoles/química , Humanos , Reproducibilidad de los Resultados , Espectrometría de Masas en Tándem/métodos
2.
Environ Sci Technol ; 58(1): 121-131, 2024 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-38118121

RESUMEN

The COVID-19 pandemic has resulted in huge amounts of face masks worldwide. However, there is a lack of awareness on the additives and their potential risk to aquatic ecosystems of face masks. To address this issue, the additives and their toxicity in 13 face masks (e.g., polypropylene, polyethylene, and polylactic acid) were determined using nontarget analysis and bioassays. A total of 826 organic additives including intermediates (14.8%), surfactants (9.3%), plasticizers (8.2%), and antioxidants (6.1%) were tentatively identified, with 213 compounds being assigned confidence levels of 1 and 2. Interestingly, polylactic acid masks contained more additives than most polypropylene or polyethylene masks. Among these additives, the concentration of tris(2-ethylhexyl) phosphate in masks was 9.4-978.2 ng/g with a 100% detection frequency. Furthermore, 13 metals such as zinc (up to 202.0 µg/g), copper (32.5 µg/g), and chromium (up to 5.7 µg/g) were detected in the face masks. The methanol extracts of the masks showed the developmental toxicity, swimming behavior, and/or endocrine disruption in embryos/larvae of Oryzias melastigma. The findings demonstrate that face masks contain various toxic additives to marine medaka, which deserves close attention to pollution by face masks.


Asunto(s)
Oryzias , Contaminantes Químicos del Agua , Animales , Humanos , Ecosistema , Máscaras , Pandemias , Polipropilenos , Polietilenos
3.
J Appl Microbiol ; 135(1)2024 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-38111211

RESUMEN

AIM: This study aimed to understand the morphological effects of (in)organic additives on microbially induced calcium carbonate precipitation (MICP). METHODS AND RESULTS: MICP was monitored in real time in the presence of (in)organic additives: bovine serum albumin (BSA), biofilm surface layer protein A (BslA), magnesium chloride (MgCl2), and poly-l-lysine. This monitoring was carried out using confocal microscopy to observe the formation of CaCO3 from the point of nucleation, in comparison to conditions without additives. Complementary methodologies, namely scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction, were employed to assess the visual morphology, elemental composition, and crystalline structures of CaCO3, respectively, following the crystals' formation. The results demonstrated that in the presence of additives, more CaCO3 crystals were produced at 100 min compared to the reaction without additives. The inclusion of BslA resulted in larger crystals than reactions containing other additives, including MgCl2. BSA induced a significant number of crystals from the early stages of the reaction (20 min) but did not have a substantial impact on crystal size compared to conditions without additives. All additives led to a higher content of calcite compared to vaterite after a 24-h reaction, with the exception of MgCl2, which produced a substantial quantity of magnesium calcite. CONCLUSIONS: The work demonstrates the effect of several (in)organic additives on MICP and sets the stage for further research to understand additive effects on MICP to achieve controlled CaCO3 precipitation.


Asunto(s)
Carbonato de Calcio , Sporosarcina , Carbonato de Calcio/metabolismo , Cloruro de Magnesio/metabolismo , Sporosarcina/metabolismo , Precipitación Química , Microscopía Electrónica de Rastreo
4.
Environ Technol ; : 1-14, 2023 Dec 12.
Artículo en Inglés | MEDLINE | ID: mdl-38084650

RESUMEN

The application of organic additives is an efficient strategy to promote the vermicomposting of organic wastes. This study investigated the changes in earthworm growth, nutrients, enzyme activities, microbial composition, and seedling growth during 60 days of vermicomposting of white wine distillers' grains (WWDG) mixed (50:50, w/w) with green waste (GW), green waste compost (GWC), or cow dung (CD). Our data showed that GW, GWC, and CD addition significantly enhanced the survival rate (73.33%-89.17%), growth, and reproduction of earthworms compared to the control treatment. The degradation rate of TOC, the increasing rate of nutriments (total N, total P, total K, available P, available K, humic acid, NH4+, NO3-), and the germination index were significantly higher in the additive treatments than in the control treatment. Dehydrogenase, phosphatases, and urease activities were significantly elevated in the vermicompost amended with additives. The additives remarkably stimulated bacteria, such as Streptomyces, Steroidobacter, Bacillus, Luteibacter, and Rhodanobacter, etc., which were closely related to the biocontrol of phytopathogens and the decomposing recalcitrant substances. Moreover, additives significantly promoted the generation and growth parameters of tomato and lettuce seedlings when compared with the control. In summary, these results indicated that all three additives facilitated the vermicomposting of WWDG and improved the compost quality by enhancing earthworm and enzyme activities as well as altering compost bacterial community, especially when the GWC addition yields the best compost quality and shows strong potential for future application. This study developed a new method for improving WWDG utilization rate and it will promote organic waste recycling in China.

5.
Water Res ; 242: 120272, 2023 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-37393811

RESUMEN

The environmental occurrence and impact of dissolved organic matter leached from microplastics (MP-DOM) has been the subject of increased research interest. Commercial plastics, which typically contain additives, are subject to natural weathering processes and can eventually lose their additives. However, the effects of organic additives in commercial microplastics (MPs) on the release of MP-DOM under UV irradiation remain poorly understood. In this study, four polymer MPs (polyethylene; PE, polypropylene; PP, polystyrene; PS, polyvinylchloride; PVC) and four commercial MPs, including a PE zip bag, a PP facial mask, a PVC sheet, Styrofoam, were subjected to leaching under UV irradiation, and the MP-DOM was characterized using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and fluorescence excitation emission matrix-parallel factor analysis (EEM-PARAFAC). Although UV light promoted the leaching of MP-DOM from both MP groups, the amount released was more pronounced for the polymer MPs than for the commercial MPs. The commercial MP-DOM was characterized by a prominent protein/phenol-like component (C1), while a humic-like component (C2) prevailed in the polymer MPs. FT-ICR-MS identified a higher number of unique molecular formulas for the commercial than for the polymer MP-DOM. The unique molecular formulas of commercial MP-DOM included known organic additives and other breakdown products, while the polymer MP-DOM featured more pronounced unsaturated carbon structures in its identified unique formulas. Several molecular-level parameters showed significant correlations with fluorescence properties, such as CHO formulas (%) with C1 and condensed aromatic structure (CAS-like, %) with C2, suggesting the potential application of fluorescent components as an optical descriptor for the complex molecular-level composition. This study also revealed the possible high environmental reactivity of both polymer MPs and fully weathered plastics due to the unsaturated structures generated in sunlit environments.


Asunto(s)
Microplásticos , Plásticos , Materia Orgánica Disuelta , Sustancias Húmicas/análisis , Polímeros , Espectrometría de Fluorescencia/métodos
6.
Micromachines (Basel) ; 14(6)2023 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-37374736

RESUMEN

In our work, we studied thin nickel films deposited by electroless plating for use as a barrier and seed layer in the through-silicon vias (TSV) technology. El-Ni coatings were deposited on a copper substrate from the original electrolyte and with the use of various concentrations of organic additives in the composition of the electrolyte. The surface morphology, crystal state, and phase composition of the deposited coatings were studied by SEM, AFM, and XRD methods. The El-Ni coating deposited without the use of an organic additive has an irregular topography with rare phenocrysts of globular formations of hemispherical shape and a root mean square roughness value of 13.62 nm. The phosphorus concentration in the coating is 9.78 wt.%. According to the results of the X-ray diffraction studies of El-Ni, the coating deposited without the use of an organic additive has a nanocrystalline structure with an average nickel crystallite size of 2.76 nm. The influence of the organic additive is seen in the smoothening of the samples surface. The root mean square roughness values of the El-Ni sample coatings vary within 2.09-2.70 nm. According to microanalysis data the phosphorus concentration in the developed coatings is ~4.7-6.2 wt.%. The study of the crystalline state of the deposited coatings by X-ray diffraction made it possible to detect two arrays of nanocrystallites in their structure, with average sizes of 4.8-10.3 nm and 1.3-2.6 nm.

7.
J Biomed Mater Res B Appl Biomater ; 111(8): 1488-1498, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-36880533

RESUMEN

NiFeMo alloy nanoparticles were synthesized by co-precipitation in the presence of organic additives. Nanoparticles thermal evolution shows that there is a significant increase in the average size (from 28 to 60 nm), consolidating a crystalline structure of the same type as the Ni3 Fe phase but with lattice parameter a = 0.362 nm. Measurements of magnetic properties follow this morphological and structural evolution increasing saturation magnetization (Ms) by 578% and reducing remanence magnetization (Mr) by 29%. Cell viability assays on as-synthesized revealed that nanoparticles (NPs) are not cytotoxic up to a concentration of 0.4 µg/mL for both non-tumorigenic (fibroblasts and macrophages) and tumor cells (melanoma).


Asunto(s)
Nanopartículas , Temperatura , Nanopartículas/química , Magnetismo , Fibroblastos , Fenómenos Magnéticos
8.
J Hazard Mater ; 442: 130051, 2023 01 15.
Artículo en Inglés | MEDLINE | ID: mdl-36179627

RESUMEN

Biodegradable plastics (BDP) are increasingly applied; however, there has been of concerns about their environmental safety, especially from nondegradable additive compositions. Until now, data of ecotoxicity of BDP additives is scarce. Here, nematode C. elegans was used to comparatively evaluate toxicity of an isocyanate additive, i.e., Hexamethylene diisocyanate (HDI), a maleic anhydride, i.e., Diallyl maleate (DIM), and other four BDP organic additives. These additives caused lethality of nematodes at µg L-1 level, of lowest LC50 value of HDI/DIM. Uniform exposure to these additives resulted in various degrees of inhibitions in body volumes and longevity, indicating developmental toxicity. Moreover, BDP additives induced significant elevations of gst-4 expression, especially mean 123.54 %/234.29 % increase in HDI/DIM group, but reduced ges-1 expression, which indicates oxidative damages and mitochondrial dysfunction. BDP additives further caused inhibition in locomotor and food intake/excretion behavior, and related damages of glutamatergic neurons and GABAergic neurons, indicating their neurotoxicity. We found HDI and DIM presented relatively strong effects on susceptible endpoints including lethality, gst-4, mean lifespan, food intake and excretion behavior. Overall, this study suggests prominent ecotoxic risk of isocyanates and maleic anhydrides as BDP additives, which is significant for the selection of environmentally friendly BDP additives.


Asunto(s)
Plásticos Biodegradables , Caenorhabditis elegans , Animales , Anhídridos Maleicos , Plásticos Biodegradables/farmacología , Isocianatos/farmacología , Maleatos/farmacología
9.
Waste Manag ; 153: 197-208, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-36108538

RESUMEN

The effects of synthetic fertilizer and nutrient leaching are causing serious problems impacting soil function and its fertility. Mitigation of nutrient leaching and use of chemical fertilizer is crucial as fertile land adds up sustainability to climate changes. Biochar produced from agricultural bio-waste and municipal solid waste has been used for crop production and when applied in combination with organic nutrients may support mitigation of nutrient loss and adverse effects of chemical fertilizers. Different types of biochar and their application for soil enhancement have been observed, pine needle and sewage sludge derived low-temperature biochar along with compost, organic fertilizer in the form of manure and microalgal biomass may interact with soil chemistry and plant growth to impact nutrient loss and compensate the hazardous effect of chemical fertilizer, but it has not been investigated yet. This present study elaborates application of sewage sludge and pine needle biochar produced at 400 °C in an application rate of 5 % w/w and 10 t h-1 in combination with compost, manure and microalgal biomasses of Closteriopsis acicularis (BM1) and Tetradesmus nygaardi (BM2) on the growth of Chickpea (Cicer arietinum) and Fenugreek (Trigonella foenum-graecum) crop assessed in a pot experiment over a two crop (Chickpea - Fenugreek) cycle in Pakistan. Results depict that the pine needle biochar with additives has increased plant height by 104.1 ± 2.76 cm and fresh biomass by 49.9 ± 1.02 g, buffered the soil pH to 6.5 for optimum growth of crops and enhance carbon retention by 36 %. This study highlights the valorization of sewage sludge and pine needle into biochar and the effect of biochar augmentation, its impact on soil nutrients and plant biomass enhancement. The greener approach also mitigates and helps in the sustainable management of solid wastes.


Asunto(s)
Aguas del Alcantarillado , Suelo , Carbono , Carbón Orgánico , Fertilizantes , Estiércol , Residuos Sólidos
10.
Molecules ; 27(16)2022 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-36014443

RESUMEN

An archaeological excavation in Prostejov (Czech Republic) revealed a workshop of a local potter with colourless, pink, and blue powders presumably used to produce faience/surface decoration. A comprehensive analytical study, which combined elemental and molecular analysis techniques, was performed to shed light on the chemical composition of these unique findings. Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM EDX), inductively coupled-plasma mass spectrometry (ICP MS), flow injection analysis (FIA) with electrospray ionisation mass spectrometry (ESI MS), laser desorption ionisation mass spectrometry (LDI MS), and Raman spectroscopy were applied to reveal the elemental composition of the powders and identify the colouring agents in the pink and blue powders. The colouring agents in the pink powder were probably iron and the agent in the blue powder is Prussian blue. On top of that, it was also possible to determine the organic additives in these powders through pyrolysis gas chromatography with mass spectrometric detection (Py GC/MS), atmospheric solids analysis probe ion mobility mass spectrometry (ASAP IM MS), and LDI MS. The organic constituents were identified as plant resin, beeswax, and fats. These results point to the preparation of faience/pigment mixtures as oil paint.


Asunto(s)
Pintura , Espectrometría de Masa por Ionización de Electrospray , Colorantes/análisis , Cromatografía de Gases y Espectrometría de Masas/métodos , Pintura/análisis , Polvos , Espectrometría de Masa por Ionización de Electrospray/métodos
11.
Materials (Basel) ; 15(6)2022 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-35329455

RESUMEN

The hydration kinetics of Portland-limestone cement pastes with organic additives in the form of acetic acid and sodium acetate were studied by using solid-state 13C, 27Al and 29Si NMR spectroscopy. The evolution of the relative content of various phases was monitored over the period of one month: amorphous and crystalline calcite (in 13C spectra), ettringite, aluminum in C-S-H gel, calcium aluminates and calcium hydroaluminates (in 27Al spectra), as well as alite, belite and silicon in C-S-H gel (in 29Si spectra). The retarding effect of the additives on cement hydration at early age was demonstrated. We show that the kinetics of phase assemblage formation is influenced by the acetate ion adsorption on the surface of the anhydrous cement components and hydrated phases. The kinetics of formation of ettringite in the cement paste, depending on the addition of acetic and or sodium acetate, is discussed in the context of potential thaumasite sulfate attack.

12.
Poult Sci ; 101(4): 101696, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35150942

RESUMEN

The poultry industry contributes significantly to bridging the nutritional gap in many countries because of its meat and eggs products rich in protein and valuable nutrients at a cost less than other animal meat sources. The natural antibiotics alternatives including probiotics, prebiotics, symbiotics, organic acids, essential oils, enzymes, immunostimulants, and phytogenic (phytobiotic) including herbs, botanicals, essential oils, and oleoresins are the most common feed additives that acquire popularity in poultry industry following the ban of antibiotic growth promoters (AGPs). They are commonly used worldwide because of their unique properties and positive impact on poultry production. They can be easily mixed with other feed ingredients, have no tissue residues, improve feed intake, feed gain, feed conversion rate, improve bird immunity, improve digestion, increase nutrients availability as well as absorbability, have antimicrobial effects, do not affect carcass characters, decrease the usage of antibiotics, acts as antioxidants, anti-inflammatory, compete for stress factors and provide healthy organic products for human consumption. Therefore, the current review focuses on a comprehensive description of different natural antibiotic growth promoters' alternatives, the mode of their action, and their impacts on poultry production.


Asunto(s)
Aceites Volátiles , Aves de Corral , Alimentación Animal/análisis , Animales , Antibacterianos/farmacología , Pollos , Óvulo
13.
Nanomaterials (Basel) ; 13(1)2022 Dec 30.
Artículo en Inglés | MEDLINE | ID: mdl-36616076

RESUMEN

To study their physicochemical and antimicrobial properties, zinc oxide nanoparticles were synthesized using a simple chemical route and 4-dimethylaminobenzaldehyde (4DB) as an organic additive. ZnO nanoparticles were characterized with XRD analysis, which confirmed the presence of a hexagonal wurtzite structure with different crystalline sizes. The SEM morphology of the synthesized nanoparticles confirmed the presence of nanorods in both modifications of ZnO nanoparticles. EDS analysis proved the chemical composition of the synthesized samples via different chemical approaches. In addition, the optical absorption results indicated that the use of 4DB increased the band gap energy of the synthesized nanoparticles. The synthesized Zn8O8 and Zn8O8:4DB clusters were subjected to HOMO-LUMO analysis, and their ionization energy (I), electron affinity (A), global hardness (η), chemical potential (σ), global electrophilicity index (ω), dipole moment (µ), polarizability (αtot), first-order hyperpolarizability (ßtot), and other thermodynamic properties were determined. Furthermore, the antimicrobial properties of the ZnO nanoparticles were studied against G+ (S. aureus and B. subtilis) and G- (K. pneumoniae and E. coli) bacteria in a nutrient agar according to guidelines of the Clinical and Laboratory Standards Institute (CLSI).

14.
J Genet Eng Biotechnol ; 19(1): 122, 2021 Aug 19.
Artículo en Inglés | MEDLINE | ID: mdl-34410556

RESUMEN

BACKGROUND: Terrestrial orchids belonging to the Orchis genus are difficult to propagate and are under great pressure in their natural habitats. Studies regarding the influence of photoperiod and temperature regimes on Orchis militaris germination and morphological changes during immature seed development in vitro are scarce. Our aim was to identify photoperiod, temperature, and different nutrient media requirements for optimization of O. militaris seed germination and vigorous seedling production. RESULTS: Post-germination morphological changes were recorded with O. militaris seeds collected from 32-day-old fruits, where the percentage of O. militaris seeds without embryo was 38.4%. The highest rate of O. militaris seed germination (82.6%) was obtained on Malmgren modified terrestrial orchid medium (mM), enriched by 5% coconut water, 5% birch sap, and 0.1% AC. Nine percent of seedlings were able to reach the advanced seedling stage (stage 6) after 12 months of maintenance on this medium. In all 3 modified media (Harvais, Knudson С and Malmgren), regeneration was via the production of protocorms and seedlings without callus formation. It was proved that more abundantly vigorous protocorms were formed on the modified Harvais 2 under continuous darkness, while the subculture in Knudson C medium with AC addition could be necessary to stimulate their further development. The regeneration success of the species for in vitro conditions was increased by following its natural seasonal cycle. CONCLUSION: This study demonstrated an efficient micropropagation system for O. militaris using immature seeds and thus widely opened the perspectives for its conservation in nature. The favorable conditions of seed germination periods for in vitro culture, identified as the definite shift of temperatures and photoperiod regimes intrinsic to the species in nature, could improve seedling survival of this medicinally important orchid.

15.
BMC Chem ; 15(1): 43, 2021 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-34281617

RESUMEN

BACKGROUND: The present study evaluated the compost quality from municipal solid waste (MSW) and organic additives of coffee by-products and leaf of Millettia ferruginea. Compost sample (n = 30) was taken from fresh compost materials and MSW and different organic additive treatments (T1, T2, T3, T4, and T5). Compost treatments phytotoxicity test was conducted using lettuce seed (Lactuca Sativa L. var. crispa). Analysis of variance (ANOVA) was performed using SPSS (version 22) on major compost quality characteristics. RESULTS: The compost Physico-chemical characteristics like temperature (26.4 °C), moisture content (45.5%), electrical conductivity (4.6 mS/cm), pH (7.9), total nitrogen (1.2%) and phosphorous content (2918 ppm) in T4 and T5 were analogous but both are significantly different from T3, T2 and T1 compost treatments. Phytotoxicity test using 100% compost treatment media showed that T4 (101%) and T5 (102%) are phytonutrient for lettuce plant. While, T3 and T2; and T1 compost treatments are non-phytotoxic and moderately phytotoxic respectively to lettuce plant. CONCLUSION: Therefore, compost from MSW + M. ferruginea (T4) and MSW + coffee pulp + M. ferruginea (T5) are important for improving the physico-chemical characteristics of compost and are phytonutrient for lettuce plant. Thus, for effectively management of the 75% of organic fraction of waste generated from households in the study area, recycling methods like composting with organic additives must be used at large.

16.
Mater Sci Eng C Mater Biol Appl ; 126: 112161, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-34082966

RESUMEN

Nowadays, the nanoparticle-based delivery approach is becoming more and more attractive in gene therapy due to its low toxicity and immunogenicity, sufficient packaging capacity, targeting, and straightforward, low-cost, large-scale good manufacturing practice (GMP) production. A number of research works focusing on multilayer structures have explored different factors and parameters that can affect the delivery efficiency of pDNA. However, there are no systematic studies on the performance of these structures for enhanced gene delivery regarding the gene loading methods, the use of additional organic components and cell/particle incubation conditions. Here, we conducted a detailed analysis of different parameters such as (i) strategy for loading pDNA into carriers, (ii) incorporating both pDNA and organic additives within one carrier and (iii) variation of cell/particle incubation conditions, to evaluate their influence on the efficiency of pDNA delivery with multilayer structures consisting of inorganic cores and polymer layers. Our results reveal that an appropriate combination of all these parameters leads to the development of optimized protocols for high transfection efficiency, compared to the non-optimized process (> 70% vs. < 7%), and shows a good safety profile. In conclusion, we provide the proof-of-principle that these multilayer structures with the developed parameters are a promising non-viral platform for an efficient delivery of nucleic acids.


Asunto(s)
ADN , Técnicas de Transferencia de Gen , Terapia Genética , Tamaño de la Partícula , Plásmidos/genética , Transfección
17.
Environ Sci Pollut Res Int ; 28(6): 7440-7449, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33033925

RESUMEN

The effect of organic components including ethanol, acetic acid, and benzene on ammonia-based selective non-catalytic reduction (SNCR) process has been investigated. Experiments were performed through a quartz tube reactor with simulated flue gas and conducted from 973 to 1373 K. The combustion and pyrolysis properties of organic components were carried out first, it was found that all the combustion processes were completed ahead of the pyrolysis, and the combustion and pyrolysis temperatures for benzene are the highest among the three organic components. Ethanol addition promoted the removal of NO in the temperature range of 973 to 1073 K, and the NO reaction temperature window was broadened, while NO removal was greatly inhibited under a higher temperature over 1100 K. With regard to the effect of addition of multiple organic components on NO removal, the combination of C2H6O and C2H4O2 significantly promoted this process, while the combination of C2H6O/C2H4O2 and C6H6 showed a negative effect on NO removal. The mechanism based on the radicals' reaction has been illustrated, showing the competition of these reactions under different situations.


Asunto(s)
Contaminantes Atmosféricos , Amoníaco , Contaminantes Atmosféricos/análisis , Cinética , Oxidación-Reducción , Temperatura
18.
Front Microbiol ; 11: 581118, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33552008

RESUMEN

Little is known about the direct effects of microplastics (MPs) and their organic additives on marine bacteria, considering their role in the nutrient cycles, e.g., N-cycles through the N2-fixation, or in the microbial food web. To fill this gap of knowledge, we exposed marine bacteria, specifically diazotrophs, to pure MPs which differ in physical properties (e.g., density, hydrophobicity, and/or size), namely, polyethylene, polypropylene, polyvinyl chloride and polystyrene, and to their most abundant associated organic additives (e.g., fluoranthene, 1,2,5,6,9,10-hexabromocyclododecane and dioctyl-phthalate). Growth, protein overproduction, direct physical interactions between MPs and bacteria, phosphorus acquisition mechanisms and/or N2-fixation rates were evaluated. Cyanobacteria were positively affected by environmental and high concentrations of MPs, as opposed to heterotrophic strains, that were only positively affected with high concentrations of ~120 µm-size MPs (detecting the overproduction of proteins related to plastic degradation and C-transport), and negatively affected by 1 µm-size PS beads. Generally, the organic additives had a deleterious effect in both autotrophic and heterotrophic bacteria and the magnitude of the effect is suggested to be dependent on bacterial size. Our results show species-specific responses of the autotrophic and heterotrophic bacteria tested and the responses (beneficial: the "good," deleterious: the "bad" and/or both: the "double-sword") were dependent on the type and concentration of MPs and additives. This suggests the need to determine the threshold levels of MPs and additives concentrations starting from which significant effects can be observed for key microbial populations in marine systems, and these data are necessary for effective environmental quality control management.

19.
Chemosphere ; 232: 496-505, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31170652

RESUMEN

To prevent the worldwide spread of invasive aquatic species, the ballast water of ships may be disinfected with either physical or chemical treatment systems. Excess chemicals, such as chlorine, are neutralized before the ballast water can be discharged. Unfortunately, disinfection byproducts (DBPs) formed during treatment are not neutralized and remain potentially toxic. In this study, DBPs obtained from land-based tests of seven different ballast water treatment systems (BWTSs) have been statistically analyzed. Effect of operational factors (treatment type, holding time, source of carbon and active substance dosages) and environmental variables (salinity, pH, temperature, organic matter) were related to the formation of DBPs, such as trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs) and aldehydes. THMs and HAAs were the groups with major occurrences and concentrations detected in all BWTSs. Treatment type and source of carbon were the operational factors with major significance on DBP production, especially in chlorination systems. Salinity is the main variable determining DBP composition, as it differs between brominated-DBPs and chlorinated-DBPs. Concentration and type of organic matter (dissolved and particulate) have also a significant influence on the formation of total DBPs. According to the specific group of DBPs, some factors get significance. For instance, THMs are significantly affected by pH, and the production of aldehydes correlates positively with oxidant dose.


Asunto(s)
Desinfectantes/química , Desinfección/métodos , Navíos , Aguas Residuales/química , Contaminantes Químicos del Agua/análisis , Purificación del Agua/métodos
20.
Appl Spectrosc ; 73(5): 479-491, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-30409028

RESUMEN

Organic compounds have frequently been added into lime mortars for property modifications, in order to satisfy various functional needs in building techniques. This study applies Fourier transform infrared (FT-IR) spectroscopy in transmission, reflection, and attenuated total reflection (ATR) modes to characterize lime-based mortar specimens containing oxblood, which has been used as additive as a common practice of long history in many parts of the world. The specimens were prepared basing upon a 19th-century Italian historic recipe, with the intention to have a better understanding on the possible characteristics of such mortars. Thermal analysis, color measurement, and static contact angle test were also used. After curing, the specimens show a distinctive dark-red color on the top surface, which is different from the bulk. Color measurements on the surface suggest that this color was formed at an early stage and was able to maintain stable for a relatively long period of time. Both transmission and reflection FT-IR confirm the preferential accumulation of proteins on the top surface, which should have induced their water repellency according to the static contact angle test. In addition, specimens show weaker calcite bands in FT-IR transmission, reflection, as well as ATR spectra; the pattern of ATR spectra after the thermal analysis to 500 °C suggests the formation of amorphous calcium carbonate, which is related to the presence of oxblood.

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