Laboratory diagnosis of rabies by the fluorescent antibody test applied to brain tissues of experimentally inoculated mice and either preserved in formalin or under refrigeration

Avaliou-se a adequação do emprego de cérebros preservados em formol para o estabelecimento rápido do diagnóstico da raiva pela reação de imunofluorescência direta, utilizando a técnica de digestão enzimática de pepsina e tripsina e método de impressão para o preparo de lâminas. O delineamento proposto contou com fragmentos de cérebros de camundongos experimentalmente infectados submetidos a diferentes tratamentos de conservação, com o uso de soluções de formol com pH corrigidos, ou submetidos à refrigeração; os testes de imunofluorescência foram realizados em 10 fases experimentais, por um período de 28 dias. Os resultados da prova de imunofluorescência variaram de 58.0% a 90.0% de positividade, dependendo dos tratamentos dispensados. Nas condições do experimento, os materiais destinados à prova de imunofluorescência podem ser conservados em temperatura de refrigeração por até 96 horas; após este período aumentam os resultados irregulares devido à degradação tissular. Nos tecidos mantidos em formol e após digestão enzimática, com a aplicação do método de impressão, observou-se o fenômeno de restauração da antigenicidade do vírus rábico, permitindo uma adequada identificação através da prova de imunofluorescência; no entanto, estes procedimentos não devem substituir os métodos atualmente empregados para o diagnóstico rápido da raiva.The fitness of formalin - treated materials for use in rapid rabies diagnosis was evaluated through Fluorescent Antibody (FA) test, using the digestion technique of pepsin and trypsin and the impression method of slide preparation. To achievc this proposal, brain fragments of experimentally rabid mice were submitted to different treatments of brain preservation by either using. pH adjusted formalin solutions or refrigeration, and the FA tests were run at ten experimental phases for a test period of 28 days. The results of FA reactivity ranged from 90.0% to 58.0%, depending on the treatments submitted; under the condition of the experiment, brain specimens should be maintained at refrigerating temperature until 96 hours for suitable FA examination, over this period the results should be irregular due to tissue degradation. The preservation of brain fragments in formalin, with further enzymatic digestion of pepsin and trypsin and the use of impression method did not mask or alter the virus antigenicity for adequate identification through FA technique, although the procedures should never substitute the existing methods of rapid rabies diagnosis

Demonstração da presença de antigeno rábico nas glândulas salivares submaxilares e parótidas de cães naturalmente infectados. Emprego da reação de imunofluorescência direta em impressões de tecido glandular semimacerado

Submaxillary and parotid glands of 30 naturally rabies infected dogs were examined using the direct fluorescent antibody (FA) technique on tissue smears of semi-ground salivary glands. Mouse inoculation (MI) tests of all examined salivary glands were run in parallel and the rabies diagnosis was confirmed by means of FA and MI tests of materials taken from the Ammon's horn. Specimens taken from the submaxilar glands and Ammon's horn were 100.0% positive for FA and MI tests, however, for the specimens taken from the parotid glands it was found one negative result with both FA and MI test and 11 discrepancies: five FA negative – MI positive results and six FA positive – MI negative results. The results found in this experiment demonstrated the practicality of the FA test using smears of semi-ground salivary glands. This technique should become an alternative tool for the study of rabies pathogenesis, especially for the search of the rabies virus associated with the organs involved in the virus transmission.As glândulas salivares submaxilares e parótidas de 30 cães, naturalmente infectados pelo vlrus da raiva, foram examinadas mediante a reação de imunofluorescência direta (IFD), aplicada a raiva em impressões obtidas do tecido glandular semi-macerado. Os controles adotados foram o exame de tais glândulas através da técnica de inoculação intracerabral em camundongos (IIC) e a pesquisa da presença do vírus rábico no corno de Ammon dos respectivos animais, segundo as técnicas de IFD e de IIC. As glândulas salivares submaxilares e o corno de Ammon foram positivos em todas as oportunidades para as técnicas de IFD e IIC. As glândulas salivares parátidas revelaram um resultado negativo frente às duas técnicas referidas e 11 resultados discordantes, dos quais cinco IFD negativa – IIC positiva e seis IFD positiva - IIC negativa. Os valores observados demonstraram um bom comportamento para o exame das glândulas salivares submaxilares pela IFD aplicada à raiva em impressõe s do tecido glandular semi-macerado. Esta metodologia oferece um novo instrumento para o estudo da patogenia da raiva, particularmente em investigações que procurem esclarecer apresença do vírus ao nivel dos órgãos envolvidos com a sua transmissão

Alkylation of methyl linoleate with propene in ionic liquids in the presence of metal salts

Vegetable oils and fatty acid esters are suitable precursor molecules for the production of a variety of bio-based products and materials, such as paints and coatings, plastics, soaps, lubricants, cosmetics, pharmaceuticals, printing inks, surfactants, and biofuels. Here, we report the possibility of using Lewis acidic ionic liquids (ILs) to obtain polyunsaturated ester dimerization-oligomerization and/or, in the presence of another terminal alkene (propene), co-polymerization. In particular, we have tested the Lewis acidic mixtures arising from the addition of a proper amount of GaCl3 (X > 0.5) to two chloride-based (1-butyl-3-methylimidazolium chloride, [bmim]Cl, and 1-butylisoquinolium chloride, [BuIsoq]Cl) or by dissolution of a smaller amount of Al(Tf2N)3 (X = 0.1) in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [bmim][Tf2N]. On the basis of product distribution studies, [bmim][Tf2N]/Al(Tf2N)3 appears the most suitable medium in which methyl linoleate alkylation with propene can compete with methyl linoleate or propene oligomerization

Influência do tratamento com hormônio corticosteróide sobre a sensibilidade do cão à infecção experimental, via intramuscular, com vúus rábico de “rua”

Sixteen dogs (1 -2 years old and 8 -1 0 kg) were used. Nine of them were individually treated with 25 milligrams/day of hydrocortison acetate through the subcutaneous route three days before and on the day of rabies virus inoculation. Seven dogs were used as controls being not treated with hormone. Results showed that eight animals presented signs of rabies and died from 13 to 23 days after challenge, all of them were positive for rabies tested by the immunofluorescence and mouse inoculation tests; only one of these dogs belonged to the control group. The remaining eight animals without signs of the disease (six of them not treated with hormone), were sacrificed from 38 to 88 days after the virus challenge being observed that they were negative for the same rabies laboratory tests described above. Thus the number of dogs positive for rabies was significantly higher in animals treated with corticosteroid hormone.De 16 cães adultos experimentalmente infectados com o vírus rábico de “rua”, via intramuscular, nove receberam hormônio corticosteróide e sete constituíram o grupo controle, sem tratamento hormonal. A dosificação de hormônio consistiu da aplicação diária de 25 miligramas de acetato de delta hidrocortisona em suspensão, via subcutânea, por animal, nos três dias que antecederam e por ocasião da inoculação do vírus. Após um período de observação variável entre 13 e 23 dias da inoculação do vírus, sete dos nove animais do grupo que recebeu hormônio sucumbiram em consequência da raiva, a qual foi confirmada através dás provas de imunofluorescência direta e de inoculação intracerebral em camundongos, enquanto que apenas um dos sete animais do grupo controle, manifestou a doença. Decorrido um período de observação variável entre 38 e 88 dias após a inoculação virai, os oito animais remanescentes, dois dos quais tratados com corticosteróide e seis do grupo controle, não apresentaram sinais da raiva e foram sacrificados, mostrando-se negativos nos exames laboratoriais para diagnóstico da raiva, realizados após o sacrifício. A análise estatística dos resultados obtidos revelou que o número de animais mortos em consequência da raiva, durante os períodos de observação adotados, foi Significativamente maior para o grupo que recebeu hormônio (p < 0,05)

Biodegradation and toxicity of waste from anaerobic fermentation of stillage

Several studies have been carried out to produce biofuels by anaerobic digestion of stillage from ethanol fermentation. This type of process, known as ABE Fermentation, generates by-products such as acetone, butanol and ethanol. This fermentation can use pure or mixed cultures of anaerobic bacteria, mainly of the genus Clostridium. In this context, there is the need for deeper studies for proper disposal of the residue resulting from Anaerobic Fermentation of ethanolic stillage, hereinafter referred to as AF stillage (stillage from Anaerobic Fermentation), obtained after this fermentation. Thus, the aim of this study was to evaluate the biodegradation and toxicity of stillage from Anaerobic Fermentation. The biodegradation of AF stillage in soil samples in the presence and absence of commercial inoculum was evaluated using a respirometric method described by Bartha & Pramer, according to the standard NBR 14283 (ABNT, 1999). The production of CO2 was evaluated for 57 days. Additionally, quantification of microorganisms was carried out at the beginning and end of the experiment. Toxicity tests were performed with the microcrustacean Daphnia similis using raw AF stillage and leachate from the respirometry test, according to the standard NBR 12713 (ABNT, 2009). The results of the respirometry test showed that, after 13 days of incubation, the biodegradation efficiency of all samples was above 30%. Using the Friedman statistical test, results showed that adding the inoculum caused no statistically significant difference in the biodegradation of AF stillage. The acute toxicity tests were performed on raw AF stillage and on the leachates showed that toxicity was removed after biodegradation in soil at all concentrations used. Thus, discharge of AF stillage into soil is an alternative viable disposal.16371863187

Recent Developments and Applications of Acoustic Infrasound to Monitor Volcanic Emissions

Volcanic ash is a well-known hazard to population, infrastructure, and commercial and civil aviation. Early assessment of the parameters that control the development and evolution of volcanic plumes is crucial to effective risk mitigation. Acoustic infrasound is a ground-based remote sensing technique—increasingly popular in the past two decades—that allows rapid estimates of eruption source parameters, including fluid flow velocities and volume flow rates of erupted material. The rate at which material is ejected from volcanic vents during eruptions, is one of the main inputs into models of atmospheric ash transport used to dispatch aviation warnings during eruptive crises. During explosive activity at volcanoes, the injection of hot gas-laden pyroclasts into the atmosphere generates acoustic waves that are recorded at local, regional and global scale. Within the framework of linear acoustic theory, infrasound sources can be modelled as multipole series, and acoustic pressure waveforms can be inverted to obtain the time history of volume flow at the vent. Here, we review near-field (<10 km from the vent) linear acoustic wave theory and its applications to the assessment of eruption source parameters. We evaluate recent advances in volcano infrasound modelling and inversion, and comment on the advantages and current limitations of these methods. We review published case studies from different volcanoes and show applications to new data that provide a benchmark for future acoustic infrasound studies.Silvio De Angelis and Alejandro Diaz-Moreno are funded by NERC grant number NE/P00105X/1. Luciano Zuccarello has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 798480

Uncertainty in Detection of Volcanic Activity Using Infrasound Arrays: Examples From Mt. Etna, Italy

SD and LZ acknowledge the support from the EUROVOLC project under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 731070). The authors thank the staff of the Istituto Nazionale di Geofisica e Vulcanologia Sezione di Catania, in particular Salvo Rapisarda, Daniele Pellegrino, Mario Pulvirenti, and Danilo Contrafatto for their valuable support in the field.The injection of gas and pyroclastic material from volcanic vents into the atmosphere is a prolific source of acoustic waves. Infrasound arrays offer efficient, cost-effective, and near real-time solutions to track the rate and intensity of surface activity at volcanoes. Here, we present a simple framework for the analysis of acoustic array data, based on least-squares beamforming, that allows to evaluate the direction and speed of propagation of acoustic waves between source and array. The algorithms include a new and computationally efficient approach for quantitative assessment of the uncertainty on array measurements based on error propagation theory. We apply the algorithms to new data collected by two 6-element infrasound arrays deployed at Mt. Etna during the period July–August 2019. Our results demonstrate that the use of two infrasound arrays allowed detecting and tracking acoustic sources from multiple craters and active vents associated with degassing and ash-rich explosions, vigorous and frequent Strombolian activity, opening of new eruptive fractures and emplacement of lava flows. Finally, we discuss the potential use of metrics based on infrasound array analyses to inform eruption monitoring operations and early warning at volcanoes characterized by episodic intensification of activity.NERC Natural Environment Research Council NE/P00105X/1European Union (EU)Geoscientists without Borders grant from the Society of Exploration Geophysic

Source Mechanism of Seismic Explosion Signals at Santiaguito Volcano, Guatemala:New Insights From Seismic Analysis and Numerical Modeling

Volcanic activity at the Santiaguito dome complex (Guatemala) is characterized by lava extrusion interspersed with small, regular, gas-and-ash explosions that are believed to result from shallow magma fragmentation; yet, their triggering mechanisms remain debated. Given that the understanding of source processes at volcanoes is essential to risk assessments of future eruptions, this study seeks to shed light on those processes. We use data from a permanent seismic and infrasound network at Santiaguito volcano, Guatemala, established in 2018 and additional temporary stations, including a seismic array deployed during a 13-day field investigation in January 2019 to analyze and resolve the source characteristics of fragmentation leading to gas-and-ash explosions. Seismic data gathered within a distance of 4.5 km from the vent show a weak seismic signal 2–6 s prior to the explosions and associated main seismic signal. To resolve the source location and origin of the seismic signals, we first used ambient noise analysis to assess seismic velocities in the subsurface and then used two-dimensional spectral element modeling (SPECFEM2D) to simulate seismic waveforms. The analyzed data revealed a two-layer structure beneath the array, with a shallow, low-velocity layer (v$_{s}$ = 650 m/s) above deeper, high-velocity rocks (v$_{s}$ = 2,650 m/s). Using this velocity structure, possible source mechanisms and depths were constrained using array and particle motion analyses. The comparison of simulated and observed seismic data indicated that the precursory signal is associated with particle motion in the RZ-plane, pointing toward the opening of tensile cracks at a depth of ∼600 m below the summit; in contrast, the main signal is accompanied by a vertical single force, originating at a shallow depth of about ∼200 m. This suggests that the volcanic explosions at Santiaguito are following a bottom-up process in which tensile fractures develop at depth and enable rapid gas rise which leads to the subsequent explosion. The result indicates that explosions at Santiaguito do not occur from a single source location, but from a series of processes possibly associated with magma rupture, gas channeling and accumulation, and fragmentation. Our study provides a good foundation for further investigations at Santiaguito and shows the value of comparing seismic observations with synthetic data calculated for complex media to investigate in detail the processes leading up to gas-ash-rich explosions found at various other volcanoes worldwide