Background Two outbreaks of mastitis due to the yeast-like alga Prototheca zopfii recently occurred in dairy herds in Lombardia (Italy) involving 180 and 150 lactating cows, respectively. Objectives ...To determine the in vitro susceptibility of Prototheca isolates to conventional antifungal agents and to essential oils. Methods Twenty P. zopfii isolated from milk during these outbreaks, six P. zopfii isolated from fresh water and two Prototheca sp. reference strains were submitted to antifungal susceptibility testing by broth microdilution assay following the CLSI guidelines for yeasts. Results The tested isolates were shown to be resistant to fluconazole and caspofungin. A wide range of voriconazole MICs was observed. In contrast, amphotericin B, itraconazole and posaconazole appeared active with MICs ≤ 1 mg/L. Bergamot and tea tree oils seemed to exert an interesting activity against this yeast-like alga. Conclusions Difficulties in treating animals with conventional drugs and the potent in vitro activity of essential oils demonstrated here raise the interest in further investigations on the therapeutic use of these non-conventional natural products.
The CYGNO/INITIUM experiment Amaro, F. D.; Baracchini, Elisabetta; Benussi, L. ...
SciPost physics proceedings,
07/2023
12
Journal Article
Recenzirano
Odprti dostop
The CYGNO project for the development of a high precision optical readout gaseous TPC for directional Dark Matter search and solar neutrino spectroscopy will be presented. It is to be hosted at ...Laboratori Nazionali del Gran Sasso. CYGNO peculiar features are the use of sCMOS cameras and PMTs coupled to GEMs amplification of a helium-based gas mixture at atmospheric pressure, in order to achieve 3D tracking with head tail capability and background rejection down to O(keV) energy, to boost sensitivity to low WIMP masses. The latest R&D results within the CYGNO project will be discussed along with the underground installation and operation of a 50 l prototype, soon to be followed by a O(1) m3 experiment demonstrator in 2024-2026. The latest results on the negative ion drift operation at atmospheric pressure within CYGNO optical readout approach will be illustrated, which is the aim of the ERC Consolidator Grant project INITIUM.
CYGNO is an international collaboration with the aim of operating a ▪ optical time projection chamber (TPC) for directional Dark Matter (DM) searches and solar neutrino spectroscopy, to be deployed ...at the Laboratori Nazionali del Gran Sasso (LNGS). A ▪/▪ (60/40) mixture is used, along with a triple Gas Electron Multiplier (GEM) cascade to amplify the ionisation signal. The scintillation produced in the electron avalanches is read out using a scientific complementary metal–oxide–semiconductor (sCMOS) camera. This solution has proven to provide very high sensitivity to interactions in the few ▪ energy range. The inclusion of a hydrogen-based gas will offer an even lighter target, resulting in a more efficient energy transfer in a DM particle collision, and consequently, a lower detection threshold. Additionally, longer track lengths of light nuclear recoils are easier to detect with a clearer direction. However, the addition of such gas will contribute to quenching the scintillation, jeopardizing the TPC performance. In this work, we demonstrate the feasibility of adding 1% to 5% isobutane to the ▪/▪ (60/40) mixture by measuring the respective absolute scintillation yield output. The overall scintillation produced in the charge avalanches is not drastically suppressed by quenching due to the isobutane addition. The presence of Penning transfer from excited He atoms to isobutane molecules increases the number of electrons in the avalanches, partially compensating for the loss of scintillation due to quenching. For the highest applied GEM voltage, the total number of photons produced in the avalanche per ▪ deposited in the absorption region presents a decrease of only a factor of about three, from 2.30(20)×104 to 8.2(4)×103▪, as the isobutane content increases from 0 to 5%. The quantification of the visible component of the scintillation shows that isobutane quenches both visible and ultraviolet (UV) photons emitted by ▪/▪.
CYGNO is an international collaboration with the aim of operating a Image 3 optical time projection chamber (TPC) for directional Dark Matter (DM) searches and solar neutrino spectroscopy, to be ...deployed at the Laboratori Nazionali del Gran Sasso (LNGS). A Image 1/Image 2 (60/40) mixture is used, along with a triple Gas Electron Multiplier (GEM) cascade to amplify the ionisation signal. The scintillation produced in the electron avalanches is read out using a scientific complementary metal–oxide–semiconductor (sCMOS) camera. This solution has proven to provide very high sensitivity to interactions in the few Image 4 energy range. The inclusion of a hydrogen-based gas will offer an even lighter target, resulting in a more efficient energy transfer in a DM particle collision, and consequently, a lower detection threshold. Additionally, longer track lengths of light nuclear recoils are easier to detect with a clearer direction. However, the addition of such gas will contribute to quenching the scintillation, jeopardizing the TPC performance. In this work, we demonstrate the feasibility of adding 1% to 5% isobutane to the Image 1/Image 2 (60/40) mixture by measuring the respective absolute scintillation yield output. The overall scintillation produced in the charge avalanches is not drastically suppressed by quenching due to the isobutane addition. The presence of Penning transfer from excited He atoms to isobutane molecules increases the number of electrons in the avalanches, partially compensating for the loss of scintillation due to quenching. For the highest applied GEM voltage, the total number of photons produced in the avalanche per Image 4 deposited in the absorption region presents a decrease of only a factor of about three, from 2.30(20)×104 to 8.2(4)×103 Image 5, as the isobutane content increases from 0 to 5%. The quantification of the visible component of the scintillation shows that isobutane quenches both visible and ultraviolet (UV) photons emitted by Image 1/Image 2.
The Time Projection Chamber (TPC) is an ideal candidate to finely study the charged particle ionization in a gaseous medium. Large volume TPCs can be readout with a suitable number of channels ...offering a complete 3D reconstruction of a charged particle track, that is the sequence of its energy releases in the TPC gas volume. Moreover, He-based TPCs are very promising to study keV energy particles as nuclear recoils, opening the possibility for directional searches of Dark Matter (DM) and the study of Solar Neutrinos (SN).
In this paper we report the analysis of the data acquired with a small TPC prototype (named LEMOn) built by the CYGNO collaboration that was exposed to a beam of 450 MeV electrons at the Beam Test Facility of National Laboratories of Frascati. LEMOn is operated with a He-CF4 mixture at atmospheric pressure and is based on a Gas Electron Multipliers amplification stage that produces visible light collected by the high granularity and very good sensitivity of scientific CMOS camera. This type of readout – in conjunction with a fast light detection – allows a 3D reconstruction of the electrons tracks. The electrons are leaving a trail of clusters of ionizations corresponding to a few keV energy release each. Their study leads to predict a keV energy threshold and 1–10 mm longitudinal and 0.1–0.3 mm transverse position resolution (sigma) for nuclear recoils, very promising for the application of optically read out TPC to DM searches and SN measurements.
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