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Discharges to the aquatic environment of pharmaceuticals represent a hazard to the aquatic organisms. Subchronic assay with 17-alpha-ethinylestradiol (EE2) and in vitro essays with pharmaceuticals of environmental concern were conducted to examine the sensitivity of tissue acetylcholinesterase (AChE) and carboxylesterase (CbE) activities of Tinca tinca to them. Subchronic exposure to 17-alpha-EE2 caused significant effects on brain, liver, and muscle CbE, but no on AChE activities. Most of the pharmaceuticals tested in vitro were considered as weak inhibitors of tissular AChE activity. Depending on the tissues, some compounds were classified as moderate inhibitors of CbE activity while other were categorized as weak enzymatic inhibitors. An opposite trend was observed depending on the tissue, while brain and liver CbE activities were inhibited, the muscle CbE activity was induced. Changes experienced on enzymatic activities after exposure to pharmaceuticals might affect the physiological functions in which these enzymes are involved. In vitro exposure to 17-alpha-EE2 in tench could be an informative, but not a surrogate model to know the effect of this synthetic estrogen on AChE and CbE activities.
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Poluentes Químicos da Água , Animais , Poluentes Químicos da Água/toxicidade , Fígado/efeitos dos fármacos , Fígado/enzimologia , Cyprinidae , Acetilcolinesterase/metabolismo , Encéfalo/efeitos dos fármacos , Encéfalo/enzimologia , Inibidores da Colinesterase/toxicidade , Músculos/efeitos dos fármacos , Músculos/enzimologia , Carboxilesterase/metabolismo , Hidrolases de Éster Carboxílico/metabolismo , Hidrolases de Éster Carboxílico/antagonistas & inibidores , Colinesterases/metabolismoRESUMO
The aim of this study was to detect vector-borne pathogens (Anaplasmataceae family, Rickettsia genus, and Bartonella genus) in bats from Misiones (Argentina). Thirty-three specimens were captured over 8 days using mist nets. Twenty (60.6%) blood samples were positive (11/13 Artibeus lituratus, 4/10 Desmodus rotundus, 4/8 Carollia perspicillata, and 1/2 Myotis nigricans) by PCR for the gltA gene fragment of Bartonella. All samples were negative by PCR for the Anaplasmataceae family and Rickettsia genus. The phylogenetic analysis showed seven Bartonella genotypes. The three genotypes obtained from A. lituratus, 2 from C. perspicillata, and 1 from D. rotundus were related to Bartonella spp. from New World bats, while the sequence obtained from M. nigricans was related to Old World bats. We identified a considerable diversity of Bartonella genotypes in a small number of bats, thus further research is required to better understand the complex bat-pathogen interaction.
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Gas-phase and aqueous oxidations of formic and oxalic acids with ozone and OH radicals have been thoroughly examined by DFT methods. Such acids are not only important feedstocks for the iterative construction of other organic compounds but also final products generated by mineralization and advanced oxidation of higher organics. Our computational simulation unravels both common and distinctive reaction channels, albeit consistent with known H atom abstraction pathways and formation of hydropolyoxide derivatives. Notably, reactions with neutral ozone and OH radical proceed through low-energy concerted mechanisms involving asynchronous transition structures. For formic acid, carbonylic H-abstraction appears to be more favorable than the dissociative abstraction of the acid proton. Formation of long oxygen chains does not cause a significant energy penalty and highly oxygenated products are stable enough, even if subsequent decomposition releases environmentally benign side substances like O2 and H2O.
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This work reports the combination of ozone and solar radiation as an advanced oxidation process to remove the herbicide tritosufuron (TSF) in water. Firstly, the recalcitrance of TSF has been assessed, obtaining an ozonation second order rate constant of 5-154â¯M-1â¯min-1 in the range of pH from 5 to 8; while the rate constant with HO was found to be (1.8-3.1)·109â¯M-1â¯s-1. Secondly, the simultaneous application of simulated solar radiation in between 300 and 800â¯nm and ozone resulted positive in the oxidation rate of TSF. Mineralization extent was also higher. Less effective oxidation was achieved after limiting the radiation to the range 360-800â¯nm or 390-800â¯nm; also completely inappropriate for mineralization. Thirdly, the detected transformation products (TPs) demonstrated the vulnerability of TSF molecule to be attacked by HO in the sulfonylurea bridge. The combination of ozone and radiation of 300-800â¯nm led to the most effective removal of the TPs. Finally, after the photolytic ozonation treatment toxicity was also evaluated in terms of phytotoxicity towards the germination and root elongation of Lactuca Sativa seeds, and toxicity by immobilization tests of Daphnia Magna.
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Ozônio , Poluentes Químicos da Água , Animais , Hidrocarbonetos Fluorados , Oxirredução , Fotólise , Triazinas , Ureia/análogos & derivadosRESUMO
The treatment of slaughterhouse wastewater was investigated by both acid precipitations and by oxidation processes. Precipitation tests were developed using three acids (H2SO4, HCl and HNO3) at different operating pH (1-6). A decrease of the precipitation pH led to an increase of the conductivity values of the supernatant. Precipitation processes allowed the removal of chemical oxygen demand (COD) (41-97%), turbidity (56-99%) and total phosphorus (27-56%). Total phenols were removed (15-96%) from pHâ¯≥â¯2, depending on the precipitation process. Generally, precipitation processes decreased the hydroxide and bicarbonates species. Additionally, three different oxidation processes were tested at different concentrations (1-15â¯gâ¯L-1): Ca(ClO)2, H2O2 and CaO2. When Ca(ClO)2 and CaO2 were applied, an increase of the supernatant conductivity was achieved. COD removal ≥71% and turbidity elimination in the range of 85-100% were achieved by using oxidation processes. CaO2 was very effective to remove total phosphorus (81-96%). The increase of the oxidant concentration in H2O2 and Ca(ClO)2 oxidation processes led to a decrease in the removal of total phenols and bicarbonates species. Optical density of the microorganism cultures was efficiently eliminated (up to 100%) by oxidation processes. In addition, acid precipitation and oxidation allowed to remove total solids (TS), total volatile solids (TVS), total suspended solids (TSS), ammonia nitrogen, nitrates and biochemical oxygen demand (BOD5). Acid precipitation and oxidation produced sludge rich in organic matter and nutrients (Ca, Mg, P, Cl, Na and K). Despite the high removal efficiencies, a post-treatment following the precipitation and oxidation processes can be required.
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Matadouros , Águas Residuárias , Peróxido de Hidrogênio , Oxirredução , Esgotos , Eliminação de Resíduos LíquidosRESUMO
The use of graphene-based materials as catalysts in both ozone and ozone/radiation processes is creating interest among researchers devoted to the study of advanced oxidation processes (AOPs) for the degradation of organic pollutants in water. In this review, detailed explanations of catalytic and photocatalytic ozonation processes mediated by graphene-based materials are presented, focusing on aspects related to the preparation and characterization of catalysts, the nature of the water pollutants treated, the type of reactors and radiation sources applied, the influence of the main operating variables, catalyst activity and stability, and kinetics and mechanisms.
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Grafite/química , Ozônio/química , Poluentes Químicos da Água/química , Catálise , Oxirredução , Poluentes da Água/química , Purificação da Água/métodosRESUMO
In this work, primidone, a high persistent pharmacological drug typically found in urban wastewaters, was degraded by different ozone combined AOPs using TiO2 P25 and commercial WO3 as photocatalyst. The comparison of processes, kinetics, nature of transformation products, and ecotoxicity of treated water samples, as well as the influence of the water matrix (ultrapure water or a secondary effluent), is presented and discussed. In presence of ozone, primidone is rapidly eliminated, with hydroxyl radicals being the main species involved. TiO2 was the most active catalyst regardless of the water matrix and the type of solar (global or visible) radiation applied. The synergy between ozone and photocatalysis (photocatalytic ozonation) for TOC removal was more evident at low O3 doses. In spite of having a lower band gap than TiO2 P25, WO3 did not bring any beneficial effects compared to TiO2 P25 regarding PRM and TOC removal. Based on the transformation products identified during ozonation and photocatalytic ozonation of primidone (hydroxyprimidone, phenyl-ethyl-malonamide, and 5-ethyldihydropirimidine-4,6(1H,5H)-dione), a degradation pathway is proposed. The application of the different processes resulted in an environmentally safe effluent for Daphnia magna.
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Óxidos/química , Ozônio/química , Primidona/análise , Titânio/química , Tungstênio/química , Poluentes Químicos da Água/análise , Animais , Catálise , Daphnia/efeitos dos fármacos , Daphnia/crescimento & desenvolvimento , Radical Hidroxila/química , Cinética , Oxirredução , Processos Fotoquímicos , Luz Solar , Raios Ultravioleta , Água/química , Purificação da ÁguaRESUMO
An incipient advanced oxidation process, solar photocatalytic ozonation (SPO), is reviewed in this paper with the aim of clarifying the importance of this process as a more sustainable water technology to remove priority or emerging contaminants from water. The synergism between ozonation and photocatalytic oxidation is well known to increase the oxidation rate of water contaminants, but this has mainly been studied in photocatalytic ozonation systems with lamps of different radiation wavelength, especially of ultraviolet nature (UVC, UVB, UVA). Nowadays, process sustainability is critical in environmental technologies including water treatment and reuse; the application of SPO systems falls into this category, and contributes to saving energy and water. In this review, we summarized works published on photocatalytic ozonation where the radiation source is the Sun or simulated solar light, specifically, lamps emitting radiation to cover the UVA and visible light spectra. The main aspects of the review include photoreactors used and radiation sources applied, synthesis and characterization of catalysts applied, influence of main process variables (ozone, catalyst, and pollutant concentrations, light intensity), type of water, biodegradability and ecotoxicity, mechanism and kinetics, and finally catalyst activity and stability.
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Ozônio/química , Luz Solar , Raios Ultravioleta , Poluentes Químicos da Água/química , Purificação da Água/métodos , Biodegradação Ambiental , Catálise , Cinética , Oxirredução , Águas Residuárias/química , ÁguaRESUMO
A synthetic secondary effluent containing an aqueous mixture of emerging contaminants (ECs) has been treated by photocatalytic ozonation using Fe(3+) or Fe3O4 as catalysts and black light lamps as the radiation source. For comparative purposes, ECs have also been treated by ultraviolet radiation (UVA radiation, black light) and ozonation (pH 3 and 7). With the exception of UVA radiation, O3-based processes lead to the total removal of ECs in the mixture. The time taken to achieve complete degradation depends on the oxidation process applied. Ozonation at pH 3 is the most effective technique. The addition of iron based catalysts results in a slight inhibition of the parent compounds degradation rate. However, a positive effect is experienced when measuring the total organic carbon (TOC) and the chemical oxygen demand (COD) removals. Photocatalytic oxidation in the presence of Fe(3+) leads to 81% and 88% of TOC and COD elimination, respectively, compared to only 23% and 29% of TOC and COD removals achieved by single ozonation. The RCT concept has been used to predict the theoretical ECs profiles in the homogeneous photocatalytic oxidation process studied. Treated wastewater effluent was toxic to Daphnia magna when Fe(3+) was used in photocatalytic ozonation. In this case, toxicity was likely due to the ferryoxalate formed in the process. Single ozonation significantly reduced the toxicity of the treated wastewater.
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Ferro/química , Ozônio/química , Águas Residuárias/química , Poluentes Químicos da Água/análise , Poluentes da Água/química , Animais , Catálise , Oxirredução , Raios UltravioletaRESUMO
Our goal was to determine the presence of neutralizing antibodies against St. Louis encephalitis virus (SLEV) and West Nile virus (WNV) in sera of wild and domestic birds from Buenos Aires City, Argentina. From October 2012 to April 2013, 180 samples were collected and processed by the microneutralization technique. A 7.2% of the sampled birds were seropositive for SLEV, while no seropositive birds for WNV were detected.
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Anticorpos Antivirais/sangue , Aves/sangue , Vírus da Encefalite de St. Louis/imunologia , Vírus do Nilo Ocidental/imunologia , Animais , Argentina , Saúde da População UrbanaRESUMO
Sequential treatments consisting in a chemical process followed by a conventional biological treatment, have been applied to remove mixtures of nine contaminants of pharmaceutical type spiked in a primary sedimentation effluent of a municipal wastewater. Combinations of ozone, UVA black light (BL) and Fe(III) or Fe3O4 catalysts constituted the chemical systems. Regardless of the Advanced Oxidation Process (AOP), the removal of pharmaceutical compounds was achieved in 1 h of reaction, while total organic carbon (TOC) only diminished between 3.4 and 6%. Among selected ozonation systems to be implemented before the biological treatment, the application of ozone alone in the pre-treatment stage is recommended due to the increase of the biodegradability observed. The application of ozone followed by the conventional biological treatment leads high TOC and COD removal rates, 60 and 61%, respectively, and allows the subsequent biological treatment works with shorter hydraulic residence time (HRT). Moreover, the influence of the application of AOPs before and after a conventional biological process was compared, concluding that the decision to take depends on the characterization of the initial wastewater with pharmaceutical compounds.
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Óxido Ferroso-Férrico/química , Ferro/química , Ozônio/química , Preparações Farmacêuticas/química , Poluentes Químicos da Água/química , Catálise , Cidades , Oxirredução , Preparações Farmacêuticas/metabolismo , Esgotos/microbiologia , Raios Ultravioleta , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Poluentes Químicos da Água/metabolismoRESUMO
Removal of nine pharmaceutical compounds--acetaminophen (AAF), antipyrine (ANT), caffeine (CAF), carbamazepine (CRB), diclofenac (DCF), hydrochlorothiazide (HCT), ketorolac (KET), metoprolol (MET) and sulfamethoxazole (SMX)-spiked in a primary sedimentation effluent of a municipal wastewater has been studied with sequential aerobic biological and ozone advanced oxidation systems. Combinations of ozone, UVA black light and Fe(III) or Fe3O4 constituted the chemical systems. During the biological treatment (hydraulic residence time, HRT = 24 h), only AAF and CAF were completely eliminated, MET, SMX and HCT reached partial removal rates and the rest of compounds were completely refractory. With any ozone advanced oxidation process applied, the remaining pharmaceuticals disappear in less than 10 min. Fe3O4 or Fe(III) photocatalytic ozonation leads to 35% mineralization compared to 13% reached during ozonation alone after about 30-min reaction. Also, biodegradability of the treated wastewater increased 50% in the biological process plus another 150% after the ozonation processes. Both untreated and treated wastewater was non-toxic for Daphnia magna (D. magna) except when Fe(III) was used in photocatalytic ozonation. In this case, toxicity was likely due to the ferryoxalate formed in the process. Kinetic information on ozone processes reveals that pharmaceuticals at concentrations they have in urban wastewater are mainly removed through free radical oxidation.
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Ozônio/química , Preparações Farmacêuticas/química , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/toxicidade , Poluentes Químicos da Água/química , Animais , Biodegradação Ambiental , Carbono/química , Carbono/metabolismo , Daphnia/efeitos dos fármacos , Ferro/química , Cinética , Oxirredução , Testes de Toxicidade , Águas Residuárias/químicaRESUMO
During March 2013 a population of eared doves (Zenaida auriculata) was established in the center of City of Buenos Aires. Considering the role of these birds as host competent for Saint Louis encephalitis virus (SLEV), a CDC light trap was put in place to perform entomologic surveillance. During this month 5 pools of mosquitoes (n = 48) were collected and taxonomically determined. Three of them were classified as Culex pipiens (n = 10) and the other two were Culex spp. (n = 38). In this case, the mosquitoes species could not be determined due to that individuals were damaged. One of the Culex spp. pool was found to be positive for Saint Louis encephalitis virus by molecular techniques. This was then sequenced and classified as genotype III.
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Columbidae/virologia , Culex/virologia , Vírus da Encefalite de St. Louis/isolamento & purificação , Técnicas de Diagnóstico Molecular , Animais , Argentina , Reservatórios de Doenças/virologia , Vetores de Doenças/classificação , Vírus da Encefalite de St. Louis/classificação , Encefalite de St. Louis/transmissão , Genótipo , População UrbanaRESUMO
BACKGROUND: Rickettsioses, ehrlichioses and anaplasmoses are caused by Gram negative obligate intracellular bacteria and transmitted mainly by arthropods. AIM: To detect and perform the molecular characterization of these pathogens in ticks and domestic dogs in Bahia Blanca City (Buenos Aires, Argentina). METHODS: Fifty six blood samples from dogs and 82 ticks (75 Rhipicephalus sanguineus and 7 Amblyomma tigrinum) were studied. The samples were analyzed by PCR for Rickettsia (intergenic space 23S-5S rRNA), Ehrlichia/Anaplasma (16S rRNA), and Anaplasma platys (16S rRNA). RESULTS: 12% of R. sanguineus resulted positive for Rickettsia, identified by sequencing as Rickettsia massiliae; and 37.5% of the canine blood samples analyzed were positive for A. platys. Molecular characterization was also performed by amplification of the fragment of the citrate synthase gene (gltA) (Rickettsia genus) and the groESL gene (A. platys). Phylogenetic trees were constructed using the neighbor-joining method. These trees revealed that sequences obtained are similar to those from other geographical regions. CONCLUSION: The results indicate the presence of R. massiliae in R. sanguineus ticks for the second time in an urban area of South America and A. platys infection in dogs, being the southernmost region of Argentina where it has been notified.
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Anaplasma/genética , Anaplasmose/epidemiologia , Doenças do Cão/epidemiologia , Rhipicephalus sanguineus/microbiologia , Infecções por Rickettsia/veterinária , Rickettsia/genética , Infestações por Carrapato/veterinária , Animais , Argentina/epidemiologia , Doenças do Cão/microbiologia , Doenças do Cão/parasitologia , Cães , Filogenia , Infecções por Rickettsia/epidemiologia , Infestações por Carrapato/epidemiologia , Infestações por Carrapato/microbiologiaRESUMO
Aqueous solutions of four pharmaceutical compounds, belonging to the group of emergent contaminants of water: atenolol (ATL), hydrochlorothiazide (HCT), ofloxacin (OFX) and trimethoprim (TMP), have been treated with different oxidation systems, mainly, photocatalytic oxidation, ozonation and photocatalytic ozonation. TiO2 has been used as semiconductor for photocatalytic reactions both in the presence of air, oxygen or ozone-oxygen gas mixtures. Black light lamps mainly emitting at 365 nm were the source of radiation. In all cases, the influence of some variables (concentrations of semiconductor, ozone gas and pharmaceuticals and pH) on the removal of pharmaceuticals, total polyphenol content (TPC) and total organic carbon (TOC) was investigated. A discussion on the possible routes of pharmaceutical and intermediates (as TPC and TOC) elimination has been developed. Thus, OFX TiO2/UVA degradation mechanism seems to develop through the participation of non-hydroxyl free radical species. Furthermore, the presence of OFX inhibits the formation of hydroxyl radicals in the photocatalytic process. The most effective processes were those involving ozone that lead to complete disappearance of parent compounds in less than 30 min for initial pharmaceutical concentrations lower than 2.5 mg L(-1). In the ozonation systems, regardless of the pH and the presence of TiO2, pharmaceuticals are degraded through their direct reaction with ozone. Photocatalytic ozonation was the most efficient process for TPC and TOC removals (≥ 80% and ≥60% elimination after 2 h of treatment, respectively) as well as in terms of the ozone consumption efficiency (1, 5.5 and 4 mol of ozone consumed per mol of TOC mineralized, at pH 4, 7 and 9, respectively). Weakly acid conditions (pH 4) resulted to be the most convenient ones for TPC and TOC removal by photocatalytic ozonation. This was likely due to formation of hydroxyl radicals through the ozonide generated at these conditions.
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Atenolol/química , Hidroclorotiazida/química , Ofloxacino/química , Ozônio/química , Trimetoprima/química , Poluentes Químicos da Água/química , Adsorção , Atenolol/análise , Recuperação e Remediação Ambiental/métodos , Hidroclorotiazida/análise , Concentração de Íons de Hidrogênio , Ofloxacino/análise , Oxirredução , Oxigênio/química , Processos Fotoquímicos , Semicondutores , Titânio/química , Trimetoprima/análise , Raios Ultravioleta , Poluentes Químicos da Água/análiseRESUMO
A mixture of nine pharmaceuticals has been treated by means of the systems: UV-B(313 nm), O(3), UV-B(313 nm) + TiO(2), O(3) + UV-B(313 nm), and O(3) + UV-B(313 nm)+TiO(2). Simple photolytic or ozonation processes lead to a deficient total organic carbon (TOC) elimination after 120 min of exposure (25 and 30% conversions, respectively). Addition of a photocatalyst such as titanium dioxide significantly enhanced the mineralization degree, a 60% TOC conversion was obtained. A TiO(2) load optimum around 0.25 g L(-1) was observed. No loss in photoactivity was experienced after 2 reuses. Due to ozone photodegradation, the combination of ozone and radiation increased the generation of hydroxyl radicals. As a consequence, TOC removal was increased to a value in the proximity of 85%. The most complex system, O(3) + UV-B(313 nm) + TiO(2), achieved the highest TOC abatement (95%). Use of ozone in photocatalytic processes involves an increase in hydroxyl radical generation.
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Ozônio/química , Fotoquímica/métodos , Purificação da Água/métodos , Catálise/efeitos da radiação , Titânio/química , Raios Ultravioleta , Poluentes Químicos da Água/químicaRESUMO
Rabies is a zoonotic disease caused by the rabies virus (RABV) that causes fatal encephalitis in mammals. Bats can transmit the disease to urban canines and felines, which rarely infect humans, establishing a secondary link. The last case of human rabies in Argentina was transmitted by a dog in 2008. We present the first case of human rabies originating from an insectivorous bat, Tadarida brasiliensis, transmitted by a feral cat in Buenos Aires province, Argentina.
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Bats are reservoirs of diverse coronaviruses (CoVs), including progenitors of severe acute respiratory syndrome CoV (SARS-CoV) and SARS-CoV-2. In the Americas, there is a contrast between alphacoronaviruses (alphaCoVs) and betaCoVs: while cospeciation prevails in the latter, alphaCoV evolution is dominated by deep and recent host switches. AlphaCoV lineages are maintained by two different bat family groups, Phyllostomidae and Vespertilionidae plus Molossidae. In this study, we used a Bayesian framework to analyze the process of diversification of the lineages maintained by Molossidae and Vespertilionidae, adding novel CoV sequences from Argentina. We provide evidence that the observed CoV diversity in these two bat families is shaped by their geographic distribution and that CoVs exhibit clustering at the level of bat genera. We discuss the causes of the cocirculation of two independent clades in Molossus and Tadarida as well as the role of Myotis as the ancestral host and a major evolutionary reservoir of alphaCoVs across the continent. Although more CoV sampling efforts are needed, these findings contribute to a better knowledge of the diversity of alphaCoVs and the links between bat host species. IMPORTANCE Bats harbor the largest diversity of coronaviruses among mammals. In the Americas, seven alphacoronavirus lineages circulate among bats. Three of these lineages are shared by members of two bat families: Vespertilionidae and Molossidae. Uncovering the relationships between these coronaviruses can help us to understand patterns of cross-species transmission and, ultimately, which hosts are more likely to be involved in spillover events. We found that two different lineages cocirculate among the bat genera Molossus and Tadarida, which share roosts and have common viral variants. The bat genus Myotis functions as a reservoir of coronavirus diversity and, as such, is a key host. Although there were some spillovers recorded, there is a strong host association, showing that once a successful host jump takes place, it is transmitted onward to members of the same bat genus.
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Alphacoronavirus , COVID-19 , Quirópteros , Humanos , Animais , Teorema de Bayes , Filogenia , SARS-CoV-2/genética , AméricaRESUMO
This review renewed insight into the existing complex and contradictory mechanisms of catalytic ozonation by two-dimensional layered carbon-based materials (2D-LCMs) for degradation toxic refractory organics in aqueous solution. Migration and capture of active electrons are central to catalytic ozonation reactions, which was not studied or reviewed more clearly. Based on this perspective, the catalytic ozonation potential of 2D-LCMs synthesized by numerous methods is firstly contrasted to guide the design of subsequent carbon based-catalysts, and not limited to 2D-LCMs. Matching ROS to active sites is a key step in understanding the catalytic mechanism. The structure-activity relationships between reported numerous active sites and ROS evolution is then constructed. Result showed that OH could be produced by -OH, -C=O, -COOH groups, defective sites, immobilized metal atoms, doped heteroatoms and photo-induced electrons; and O2- could be produced by -OH groups and sp2-bonded carbon. The normalized model further be used to visually compare the contribution degree of various regulatory methods to performance improvement. More importantly, this review calls for 2D-LCMs-based catalytic ozonation to be studied without circumventing the issue of structural stability, which would lead to many proposals of catalysts and its involved catalytic reaction mechanism being meaningless.
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Ozônio , Poluentes Químicos da Água , Purificação da Água , Carbono , Catálise , Ozônio/química , Espécies Reativas de Oxigênio , Poluentes Químicos da Água/análiseRESUMO
Doxycycline (Dxy) and Norfloxacin (Nfx) have been oxidized by means of different technologies of increasing complexity. Preliminary experiments showed that activated carbon adsorption (1.0 g L⻹) of these antibiotics (C(Antibiotic) = 5 × 10â»5 M) led to a 60 and 85 % of total organic carbon (TOC) removal, however, a significant decrease in adsorption capacity was experienced after several reuses of the adsorbent. UV-C irradiation of Dxy (20 % removal in 2 h) or Nfx (90 % removal in 2 h) did not affect the initial TOC content of the solution while single ozonation (C(O3) gas inlet concentration = 15.0 ppm) led to the instantaneous disappearance of the parent compounds while TOC conversion values in the proximity of 40 % were obtained. Complex systems based on the combination of ozone, UV-C radiation, titanium dioxide and activated carbon led to similar TOC removals of the order of 70 and 65 % for Dxy and Nfx, respectively. An attempt has been made to calculate the quantum yield and direct ozonation rate constants for doxycycline and norfloxacin. Additionally, the best systems, i.e., the O3 and O3/UV-C processes, have been simulated by a pseudoempirical model by considering TOC as a surrogate parameter.