231 research outputs found
Antiproton modulation in the Heliosphere and AMS-02 antiproton over proton ratio prediction
We implemented a quasi time-dependent 2D stochastic model of solar modulation
describing the transport of cosmic rays (CR) in the heliosphere. Our code can
modulate the Local Interstellar Spectrum (LIS) of a generic charged particle
(light cosmic ions and electrons), calculating the spectrum at 1AU. Several
measurements of CR antiparticles have been performed. Here we focused our
attention on the CR antiproton component and the antiproton over proton ratio.
We show that our model, using the same heliospheric parameters for both
particles, fit the observed anti-p/p ratio. We show a good agreement with
BESS-97 and PAMELA data and make a prediction for the AMS-02 experiment
Microplastics, microfibres and nanoplastics cause variable sub-lethal responses in mussels (Mytilus spp.)
We compare the toxicity of microplastics, microfibres and nanoplastics on mussels. Mussels (Mytilus
spp.) were exposed to 500 ng mL-1 of 20 µm polystyrene microplastics, 10x30 µm polyamide
microfibres or 50 nm polystyrene nanoplastics for 24 h or 7 days. Biomarkers of immune response,
oxidative stress response, lysosomal destabilisation and genotoxic damage were measured in
haemolymph, digestive gland and gills. Microplastics and microfibres were observed in the digestive
glands, with significantly higher plastic concentrations after 7-days exposure (ANOVA, P<0.05).
Nanoplastics had a significant effect on hyalinocyte-granulocyte ratios (ANOVA, P<0.05), indicative of
a heightened immune response. SOD activity was significantly increased followed 24 h exposure to
plastics (two-way ANOVA, P<0.05), but returned to normal levels after 7-days exposure. No evidence
of lysosomal destabilisation or genotoxic damage was observed from any form of plastic. The study
highlights how particle size is a key factor in plastic particulate toxicity
Latitudinal Dependence of Cosmic Rays Modulation at 1 AU and Interplanetary-Magnetic-Field Polar Correction
The cosmic rays differential intensity inside the heliosphere, for energy
below 30 GeV/nuc, depends on solar activity and interplanetary magnetic field
polarity. This variation, termed solar modulation, is described using a 2-D
(radius and colatitude) Monte Carlo approach for solving the Parker transport
equation that includes diffusion, convection, magnetic drift and adiabatic
energy loss. Since the whole transport is strongly related to the
interplanetary magnetic field (IMF) structure, a better understanding of his
description is needed in order to reproduce the cosmic rays intensity at the
Earth, as well as outside the ecliptic plane. In this work an interplanetary
magnetic field model including the standard description on ecliptic region and
a polar correction is presented. This treatment of the IMF, implemented in the
HelMod Monte Carlo code (version 2.0), was used to determine the effects on the
differential intensity of Proton at 1\,AU and allowed one to investigate how
latitudinal gradients of proton intensities, observed in the inner heliosphere
with the Ulysses spacecraft during 1995, can be affected by the modification of
the IMF in the polar regions.Comment: accepted for publication inAdvances in Astronom
Suprathermal particle addition to solar wind pressure: possible influence on magnetospheric transmissivity of low energy cosmic rays?
Energetic (suprathermal) solar particles, accelerated in the interplanetary
medium, contribute to the solar wind pressure, in particular during high solar
activity periods. We estimated the effect of the increase of solar wind
pressure due to suprathermal particles on magnetospheric transmissivity of
galactic cosmic rays in the case of one recent solar event
Diversity of vaginal microbiome and metabolome during genital infections
We characterized the vaginal ecosystem during common infections of the female genital tract, as vulvovaginal candidiasis (VVC, n\u2009=\u200918) and Chlamydia trachomatis infection (CT, n\u2009=\u200920), recruiting healthy (HC, n\u2009=\u200921) and bacterial vaginosis-affected (BV, n\u2009=\u200920) women as references of eubiosis and dysbiosis. The profiles of the vaginal microbiome and metabolome were studied in 79 reproductive-aged women, by means of next generation sequencing and proton based-nuclear magnetic resonance spectroscopy. Lactobacillus genus was profoundly depleted in all the genital infections herein considered, and species-level analysis revealed that healthy vaginal microbiome was dominated by L. crispatus. In the shift from HC to CT, VVC, and BV, L. crispatus was progressively replaced by L. iners. CT infection and VVC, as well as BV condition, were mainly characterised by anaerobe genera, e.g. Gardnerella, Prevotella, Megasphaera, Roseburia and Atopobium. The changes in the bacterial communities occurring during the genital infections resulted in significant alterations in the vaginal metabolites composition, being the decrease of lactate a common marker of all the pathological conditions. In conclusion, according to the taxonomic and metabolomics analysis, we found that each of the four conditions is characterized by a peculiar vaginal microbiome/metabolome fingerprint
Distribution of ermB, ermF, tet(W), and tet(M) resistance genes in the vaginal ecosystem of women during pregnancy and puerperium
The inhabitants of the vaginal ecosystem can harbor genetic determinants conferring antimicrobial resistance. However, detailed data about the distribution of resistance genes in the vaginal microbiome of pregnant women are still lacking. Therefore, we assessed the presence of macrolide (i.e., erm genes) and tetracycline (i.e., tet genes) resistance markers in the vaginal environment of Caucasian women at different gestational ages. Furthermore, the detection of resistance genes was related to the composition of the vaginal microbiota. A total of 228 vaginal samples, collected at different trimesters of pregnancy or during the puerperium, were tested for the presence of ermB, ermF, tet(W), and tet(M) by in-house end-point PCR assays. The composition of the vaginal microbiota was assessed through a microscopic evaluation (i.e., Nugent score) and by means of sequencing V3–V4 hypervariable regions of the bacterial 16 rRNA gene. Overall, the most detected resistance gene was tet(M) (76.7%), followed by ermB (55.2%). In 17% of women, mainly with a ‘normal’ vaginal microbiota, no resistance genes were found. Except for tet(W), a significant correlation between the positivity of resistance genes and a dysbiotic vaginal status (i.e., bacterial vaginosis (BV)) was noticed. Indeed, samples positive for at least one resistance determinant were characterized by a decrease in Lactobacillus spp. and an increase of BV-related genera (Prevotella, Gardnerella, Atopobium, Sneathia). A high predominance of vaginal Lactobacillus spp. (>85%) was associated with a lower risk of tet(W) gene detection, whereas the presence of Megasphaera (>1%) increased the risk of positivity for all analyzed genes. Different types of vaginal microbiota are associated with peculiar resistance profiles, being a lactobacilli-dominated ecosystem poor in or free of resistance genes. These data could open new perspectives for promoting maternal and neonatal health
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